Microvascular Disease, Peripheral Artery Disease, and Amputation

Diuretics and risk of major adverse limb events in patients with type-2 diabetes: An observational retrospective study

AIM

In patients with type-2 diabetes mellitus (T2DM), sodium-glucose co-transporter 2 inhibitors are suspected to increase the risk of amputation. "Traditional" diuretics may increase major adverse limb events (MALEs), but the evidence is weak. We studied the association between common diuretics (i.e. thiazides, loop- and potassium-sparing diuretics) and MALEs/amputations in patients with T2DM.

METHODS

Consecutive T2DM patients without cardiovascular history referred to our center for cardiovascular check-ups were retrospectively studied. Follow-up data on MALEs were collected. We used Cox models to assess the association between diuretics and MALEs, or amputation alone. A propensity score with inverse probability of diuretic treatment weighting (IPTW) analysis was performed.

RESULTS

We studied 1309 patients, (59.5 ± 10.7 years, 51 % females) with diabetes duration of 9.1 ± 8.5 years, among whom 402 (30 %) were taking diuretics. During a follow-up of 3.8 ± 1.64 years, 121 (9.1 %) had MALEs, including 19 (1.4 %) amputations. Death occurred in 111 patients and the proportion of death was significantly different between groups: patients with diuretics n = 49, 44.1% vs patients without diuretics n = 62, 55.9 %, P = 0.001. Diuretics, in multivariable analysis, were associated with MALEs (aHR[95 %CI] 1.96[1.32;2.91] P = 0.001), even after adjustment on propensity score (aHR 1.66[1.08;2.56] P = 0.02) and IPTW analysis (aHR 1.76[1.67;1.84] P < 0.0001). This risk was particularly increased in case of an abnormal ankle-brachial index (aHR 2.29[1.32;3.96], P = 0.003) at baseline. Looking at diuretic classes separately, the adjusted risk was increased with loop diuretics (aHR 2.56[1.16;5.64] P = 0.020), thiazides (aHR 2.21[1.37;3.57] P = 0.001) or potassium sparing diuretics (aHR 2.56[1.16;5.64] P = 0.020).

CONCLUSION

Diuretic treatment weighting may be associated with increased risk of MALEs. We identified several markers of increased risk of limb events where the use of diuretics should be considered with caution.

Peripheral artery disease and risk of kidney outcomes: The Atherosclerosis Risk in Communities (ARIC) study

BACKGROUND AND AIMS

The potential impact of peripheral artery disease (PAD) on kidney outcomes is not well understood. The aim of this study was to explore the association between PAD and end-stage kidney disease (ESKD) and chronic kidney disease (CKD).

METHODS

Among 14,051 participants (mean age 54 [SD 6 years]) from the Atherosclerosis Risk in Communities study, we categorized PAD status as symptomatic PAD (intermittent claudication or leg revascularization), asymptomatic PAD (ankle-brachial index [ABI] ≤0.90 without clinical history of symptoms), and ABI 0.91-1.00, 1.01-1.10, 1.11-1.20 (reference), 1.21-1.30, and >1.30. We evaluated their associations with two kidney outcomes: ESKD (the need of renal replacement therapy or death due to kidney disease) and CKD (ESKD cases or an estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m2 with a ≥25 % decline from the baseline) using multivariable Cox proportional hazards models.

RESULTS

Over ∼30 years of follow-up, there were 598 cases of incident ESKD and 4686 cases of incident CKD. After adjusting for potential confounders, both symptomatic PAD and asymptomatic PAD conferred a significantly elevated risk of ESKD (hazard ratio 2.28 [95 % confidence interval 1.23-4.22] and 1.75 [1.19-2.57], respectively). Corresponding estimates for CKD were 1.54 (1.14-2.09) and 1.63 (1.38-1.93). Borderline low ABI 0.91-1.00 also showed elevated risk of adverse kidney outcomes after adjustment for demographic variables. Largely consistent results were observed across demographic and clinical subgroups.

CONCLUSIONS

Symptomatic PAD and asymptomatic PAD were independently associated with an elevated risk of ESKD and CKD. These results highlight the importance of monitoring kidney function in persons with PAD, even when symptoms are absent.

Competing risk analysis to estimate amputation incidence and risk in lower-extremity peripheral artery disease

Background: Patients with peripheral artery disease face high amputation and mortality risk. When assessing vascular outcomes, consideration of mortality as a competing risk is not routine. We hypothesize standard time-to-event methods will overestimate major amputation risk in chronic limb-threatening ischemia (CLTI) and non-CLTI. Methods: Patients undergoing peripheral vascular intervention from 2017 to 2018 were abstracted from the Vascular Quality Initiative registry and stratified by mean age (⩾ 75 vs < 75 years). Mortality and amputation data were obtained from Medicare claims. The 2-year cumulative incidence function (CIF) and risk of major amputation from standard time-to-event analysis (1 - Kaplan-Meier and Cox regression) were compared with competing risk analysis (Aalen-Johansen and Fine-Gray model) in CLTI and non-CLTI. Results: A total of 7273 patients with CLTI and 5095 with non-CLTI were included. At 2-year follow up, 13.1% of patients underwent major amputation and 33.4% died without major amputation in the CLTI cohort; 1.3% and 10.7%, respectively, in the non-CLTI cohort. In CLTI, standard time-to-event analysis overestimated the 2-year CIF of major amputation by 20.5% and 13.7%, respectively, in patients ⩾ 75 and < 75 years old compared with competing risk analysis. The standard Cox regression overestimated adjusted 2-year major amputation risk in patients ⩾ 75 versus < 75 years old by 7.0%. In non-CLTI, the CIF was overestimated by 7.1% in patients ⩾ 75 years, and the adjusted risk was overestimated by 5.1% compared with competing risk analysis. Conclusions: Standard time-to-event analysis overestimates the incidence and risk of major amputation, especially in CLTI. Competing risk analyses are alternative approaches to estimate accurately amputation risk in vascular outcomes research.

Correlation of cerebral small vessel disease burden with outcome after lower extremity amputation

AIMS

This study assessed whether changes associated with cerebral small vessel disease (CSVD) evaluated from head computed tomography (CT) images captured for non-related clinical purposes predict overall survival (OS), leg salvage (LS), and amputation-free survival (AFS) after lower extremity amputation (LEA).

METHODS

We retrospectively included a cohort of 240 patients who had undergone a lower extremity amputation in Tampere University Hospital between the years 2007 and 2020 and had a head CT scan (within one year before amputation). A neuroradiologist graded the white matter lesions (WMLs) and reported infarcts, and the latter's effects on OS, LS, and AFS were evaluated.

RESULTS

Altogether, 162 (67.5 %) and 91 (38.1 %) patients had WMLs and infarcts, respectively. Mild/moderate (HR 1.985, CI 95 % 1.317-2.992) and severe (HR 2.259, CI 95 % 1.501-3.399) WMLs and infarcts (HR 1.413, CI 95 % 1.029-1.940) were associated with inferior OS. After a minor amputation, mild/moderate (HR 2.012, CI 95 % 1.054-3.843) and severe (HR 3.879, CI 95 % 2.096-7.180) WMLs were similarly associated with inferior AFS.

CONCLUSIONS

Overall, WML and infarcts detected on head CT scans were associated with impaired OS after LEA and AFS after minor LEA. Evaluation of CSVD could provide useful prognostic information for clinicians.

Predictive model for novel subtypes of patients undergoing lower extremity amputation for peripheral artery disease: An unsupervised machine learning study

Background

Peripheral artery disease (PAD) represents the frequently seen circulatory condition related to a risk of critical limb ischemia and amputation. Critical lower extremity ischemia may require amputation, and the outcomes vary. In this study, we developed an artificial intelligence (AI)-driven predictive model for PAD subtypes to assess risk among patients more precisely and accurately to predict disease progression.

Methods

The present retrospective study examined clinical data in PAD patents undergoing lower extremity amputation. The data were analyzed using an unsupervised machine learning algorithm (UMLA) for subgroup identification and risk stratification. The clustering result accuracy was validated by analyzing the follow-up data of clusters. Finally, we built the prediction model with binary logistic regression.

Results

In total, we enrolled 507 cases into this work. Two distinct subgroups, consisting of Clusters 1 and 2, were identified by UMLA; those from Cluster 1 showed markedly poorer conditions and prognostic outcomes compared with those from Cluster 2. With regard to the new PAD subtype, we established a nomogram with eight predictive factors, including gender, age, smoking history, diabetes and coronary heart disease history, albumin levels, endovascular intervention, and amputation level. The nomogram could accurately categorize patients into two identified clusters, and the area under receiver operating characteristic curve was 0.861 (95 % confidence interval: 0.830-0.893).

Conclusion

In this study, UMLA was used to identify new phenotypic subgroups among PAD cases who showed different risks of amputation. Our constructed AI-driven predictive model for PAD subtypes showed that it can be used for risk stratification and clinical management with high accuracy and reliability.

Role of long noncoding RNAs in diabetes-associated peripheral arterial disease

Diabetes mellitus (DM) is a metabolic disease that heightens the risks of many vascular complications, including peripheral arterial disease (PAD). Various types of cells, including but not limited to endothelial cells (ECs), vascular smooth muscle cells (VSMCs), and macrophages (MΦs), play crucial roles in the pathogenesis of DM-PAD. Long non-coding RNAs (lncRNAs) are epigenetic regulators that play important roles in cellular function, and their dysregulation in DM can contribute to PAD. This review focuses on the developing field of lncRNAs and their emerging roles in linking DM and PAD. We review the studies investigating the role of lncRNAs in crucial cellular processes contributing to DM-PAD, including those in ECs, VSMCs, and MΦ. By examining the intricate molecular landscape governed by lncRNAs in these relevant cell types, we hope to shed light on the roles of lncRNAs in EC dysfunction, inflammatory responses, and vascular remodeling contributing to DM-PAD. Additionally, we provide an overview of the research approach and methodologies, from identifying disease-relevant lncRNAs to characterizing their molecular and cellular functions in the context of DM-PAD. We also discuss the potential of leveraging lncRNAs in the diagnosis and therapeutics for DM-PAD. Collectively, this review provides a summary of lncRNA-regulated cell functions contributing to DM-PAD and highlights the translational potential of leveraging lncRNA biology to tackle this increasingly prevalent and complex disease.

Standardization and clinical applications of retinal imaging biomarkers for cardiovascular disease: a Roadmap from an NHLBI workshop

The accessibility of the retina with the use of non-invasive and relatively low-cost ophthalmic imaging techniques and analytics provides a unique opportunity to improve the detection, diagnosis and monitoring of systemic diseases. The National Heart, Lung, and Blood Institute conducted a workshop in October 2022 to examine this concept. On the basis of the discussions at that workshop, this Roadmap describes current knowledge gaps and new research opportunities to evaluate the relationships between the eye (in particular, retinal biomarkers) and the risk of cardiovascular diseases, including coronary artery disease, heart failure, stroke, hypertension and vascular dementia. Identified gaps include the need to simplify and standardize the capture of high-quality images of the eye by non-ophthalmic health workers and to conduct longitudinal studies using multidisciplinary networks of diverse at-risk populations with improved implementation and methods to protect participant and dataset privacy. Other gaps include improving the measurement of structural and functional retinal biomarkers, determining the relationship between microvascular and macrovascular risk factors, improving multimodal imaging 'pipelines', and integrating advanced imaging with 'omics', lifestyle factors, primary care data and radiological reports, by using artificial intelligence technology to improve the identification of individual-level risk. Future research on retinal microvascular disease and retinal biomarkers might additionally provide insights into the temporal development of microvascular disease across other systemic vascular beds.

The Effect of Revascularization on Lower Limb Circulation Parameters in Symptomatic Peripheral Arterial Disease

Background: The prevalence of peripheral arterial disease and the number of revascularization procedures performed in symptomatic patients are steadily increasing. However, uncertainties remain regarding hemodynamic monitoring after revascularization and the prediction of clinical outcomes. This study aimed to investigate hemodynamic parameters with a focus on the microvasculature. Methods: This prospective, single-center study included 29 patients (15 with intermittent claudication [IC] and 14 with chronic limb-threatening ischemia [CLTI]). Before and after the revascularization procedure, in addition to the ankle-brachial index (ABI), microperfusion parameters, including microvascular blood flow, capillary oxygen saturation (SO2), and relative hemoglobin content (rHb), were assessed with lightguide spectrophotometry combined with laser Doppler flowmetry using an oxygen-to-see (O2C) device in the horizontal and elevated leg positions. Results: At baseline, SO2 in the elevated leg position was significantly lower in patients with CLTI than in those with IC (p = 0.0189), whereas the other microcirculatory parameters and ABI values were not significantly different. Patients with diabetes mellitus had a higher flow rate than those without in the horizontal leg position (p = 0.0162) but not in the elevated leg position. After successful revascularization, the flow increased immediately and significantly in both positions, whereas SO2, rHb, and the ABI did not. Conclusions: Elevated leg SO2 was significantly lower in CLTI than in clinically compensated peripheral arterial disease, whereas microvascular flow was a suitable surrogate parameter indicating successful revascularization. In studies using surgical or interventional revascularization procedures, noninvasive hemodynamic monitoring of the microcirculation at the foot level might be beneficial.

Risk factors and predictors of prolonged hospital stay in the clinical course of major amputations of the upper and lower extremity a retrospective analysis of a level 1-trauma center

PURPOSE

The objective was to analyze the treatment and complications of the patients after a major amputation of the upper and lower extremities. Risk factors and predictors of a prolonged hospital stay should be outlined.

METHODS

This is a retrospective study of a national Level-1 Trauma center in Germany. In a 10-year period, patients were identified by major amputations in the upper and lower extremities. The medical reports were considered and the results were split into four main groups with analysis on basic-, clinical data, the course on intensive care unit and the outcome. A recovery index was established. The patients' degree of recovery was summed up. Statistical analysis was performed.

RESULTS

81 patients were included. A total of 39 (48.1%) major amputations were carried out on the lower leg and 34 (42.0%) involved the thigh. There were two instances (2.5%) of hip joint disarticulation. 6 major amputations were done on the upper extremities (n = 3 on the upper arm, n = 3 on the forearm). 13.83 ± 17.10 days elapsed between hospital admission and major amputation. The average length of hospital stay was 38.49 ± 26,75 days with 5.06 ± 11.27 days on intensive care unit. Most of the patients were discharged home followed by rehabilitation. A significant correlation was found between the hospital length of stay and the increasing number of operations performed (p = 0.001). The correlation between the hospital length of stay and the CRP level after amputation was significant (p = 0.003).

CONCLUSIONS

Major amputations in trauma patients lead to a prolonged stay in hospital due to severe diseases and complications. Especially infections and surgical revisions cause such lengthenings.

2024 ACC/AHA/AACVPR/APMA/ABC/SCAI/SVM/SVN/SVS/SIR/VESS Guideline for the Management of Lower Extremity Peripheral Artery Disease: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

The "2024 ACC/AHA/AACVPR/APMA/ABC/SCAI/SVM/SVN/SVS/SIR/VESS Guideline for the Management of Lower Extremity Peripheral Artery Disease" provides recommendations to guide clinicians in the treatment of patients with lower extremity peripheral artery disease across its multiple clinical presentation subsets (ie, asymptomatic, chronic symptomatic, chronic limb-threatening ischemia, and acute limb ischemia).

METHODS

A comprehensive literature search was conducted from October 2020 to June 2022, encompassing studies, reviews, and other evidence conducted on human subjects that was published in English from PubMed, EMBASE, the Cochrane Library, CINHL Complete, and other selected databases relevant to this guideline. Additional relevant studies, published through May 2023 during the peer review process, were also considered by the writing committee and added to the evidence tables where appropriate.

STRUCTURE

Recommendations from the "2016 AHA/ACC Guideline on the Management of Patients With Lower Extremity Peripheral Artery Disease" have been updated with new evidence to guide clinicians. In addition, new recommendations addressing comprehensive care for patients with peripheral artery disease have been developed.

2024 ACC/AHA/AACVPR/APMA/ABC/SCAI/SVM/SVN/SVS/SIR/VESS Guideline for the Management of Lower Extremity Peripheral Artery Disease: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

The "2024 ACC/AHA/AACVPR/APMA/ABC/SCAI/SVM/SVN/SVS/SIR/VESS Guideline for the Management of Lower Extremity Peripheral Artery Disease" provides recommendations to guide clinicians in the treatment of patients with lower extremity peripheral artery disease across its multiple clinical presentation subsets (ie, asymptomatic, chronic symptomatic, chronic limb-threatening ischemia, and acute limb ischemia).

METHODS

A comprehensive literature search was conducted from October 2020 to June 2022, encompassing studies, reviews, and other evidence conducted on human subjects that was published in English from PubMed, EMBASE, the Cochrane Library, CINHL Complete, and other selected databases relevant to this guideline. Additional relevant studies, published through May 2023 during the peer review process, were also considered by the writing committee and added to the evidence tables where appropriate.

STRUCTURE

Recommendations from the "2016 AHA/ACC Guideline on the Management of Patients With Lower Extremity Peripheral Artery Disease" have been updated with new evidence to guide clinicians. In addition, new recommendations addressing comprehensive care for patients with peripheral artery disease have been developed.

Multi-modality imaging for assessment of the microcirculation in peripheral artery disease: Bench to clinical practice

Peripheral artery disease (PAD) is a highly prevalent disorder with a high risk of mortality and amputation despite the introduction of novel medical and procedural treatments. Microvascular disease (MVD) is common among patients with PAD, and despite the established role as a predictor of amputations and mortality, MVD is not routinely assessed as part of current standard practice. Recent pre-clinical and clinical perfusion and molecular imaging studies have confirmed the important role of MVD in the pathogenesis and outcomes of PAD. The recent advancements in the imaging of the peripheral microcirculation could lead to a better understanding of the pathophysiology of PAD, and result in improved risk stratification, and our evaluation of response to therapies. In this review, we will discuss the current understanding of the anatomy and physiology of peripheral microcirculation, and the role of imaging for assessment of perfusion in PAD, and the latest advancements in molecular imaging. By highlighting the latest advancements in multi-modality imaging of the peripheral microcirculation, we aim to underscore the most promising imaging approaches and highlight potential research opportunities, with the goal of translating these approaches for improved and personalized management of PAD in the future.

Clinical physiology: the crucial role of MRI in evaluation of peripheral artery disease

Peripheral artery disease (PAD) is a common vascular disease that primarily affects the lower limbs and is defined by the constriction or blockage of peripheral arteries and may involve microvascular dysfunction and tissue injury. Patients with diabetes have more prominent disease of microcirculation and develop peripheral neuropathy, autonomic dysfunction, and medial vascular calcification. Early and accurate diagnosis of PAD and disease characterization are essential for personalized management and therapy planning. Magnetic resonance imaging (MRI) provides excellent soft tissue contrast and multiplanar imaging capabilities and is useful as a noninvasive imaging tool in the comprehensive physiological assessment of PAD. This review provides an overview of the current state of the art of MRI in the evaluation and characterization of PAD, including an analysis of the many applicable MR imaging techniques, describing the advantages and disadvantages of each approach. We also present recent developments, future clinical applications, and future MRI directions in assessing PAD. The development of new MR imaging technologies and applications in preclinical models with translation to clinical research holds considerable potential for improving the understanding of the pathophysiology of PAD and clinical applications for improving diagnostic precision, risk stratification, and treatment outcomes in patients with PAD.

Association between Statin use and Incident Peripheral Artery Disease According to Race, Age, and Presence of Depression in the Multi-Ethnic Study of Atherosclerosis

BACKGROUND

Peripheral artery disease (PAD) is associated with high morbidity and mortality and has been commonly described as a coronary heart disease equivalent. Statin medications are recommended for primary prevention of atherosclerotic cardiovascular disease (CVD) among other indications. Therefore, understanding the longitudinal relationship of incident PAD is necessary to inform future research on how to prevent the disease. Depression complicates CVD patients' ability to properly adhere to their medications, yet the effect of depression on the relationship between statin use and incident PAD is understudied. People with PAD have a higher incidence of depressive symptoms than people without PAD. Black American and Hispanic populations are disproportionately affected by both PAD and depression yet research on the modifying effect of either race or depression on the relationship between statin use and onset of PAD is minimal. While statin utilization is highest for ages 75-84 years, there is minimal evidence of favorable risk-benefit balance. Consequently, in this project, we examined the relationship between statin use and incident PAD and whether this relationship is modified by race/ethnicity, depressive symptoms, or age.

METHODS

We used data on participants from the Multi-Ethnic Study of Atherosclerosis from visit 1 (2000) through study visit 6 (2020) who had three separate measurements of the ankle-brachial index (ABI) taken at visit 1, visit 3, and visit 5. Incident PAD was defined as 1) incident lower extremity amputation or revascularization or 2) ABI less than 0.90 coupled with ABI decrease greater than 0.15 over the follow-up period. Statin use was noted on the study visit prior to incident PAD diagnosis while depressive symptoms were measured at exam 1, visit 3, and visit 5. Propensity score matching was implemented to create balance between the participants in the two treatment groups, that is, statin-treated and statin-untreated groups, to reduce the problem of confounding by indication. Propensity scores were calculated using multivariate logistic regression model to estimate the probability of receiving statin treatment. We used Cox proportional hazards regression to investigate the relationship between time-dependent statin use as well as other risk factors with incident PAD, overall and stratified by 1) race, 2) depression status, and 3) age.

RESULTS

A total of 4,210 participants were included in the final matched analytic cohort. There were 810 incident cases (19.3%) of PAD that occurred over an average (mean) of 11.3 years (SD = 5.7) of follow-up time. In the statin-treated group, and with an average follow-up time of 12.5 years (SD = 5.6), there were 281 cases (13.4%) of incident PAD with the average follow-up time of 10.1 years (SD = 5.5), whereas in the statin-untreated group, there were 531 cases (25.2%) (P < 0.001). Results demonstrate a lower risk of PAD event in the statin-treated group compared to the untreated group (hazard ratio [HR] = 0.45, 95% confidence interval [CI]: 0.33-0.62) over the span of 18.5 years. The interactions between 1) depression and 2) race with statin use for incident PAD were not significant. However, other risk factors which were significant included Black American race that had approximately 30% lower hazard of PAD compared to non-Hispanic White (HR = 0.70, 95% CI: 0.58-0.84); age-stratified models were also fitted, and stain use was still a significant treatment factor for ages 45-54 (HR = 0.45, 95% CI: 0.33-0.63), 55-64 (HR = 0.61, 95% CI: 0.46-0.79), and 65-74 years (HR = 0.61, 95% CI: 0.48-0.78) but not for ages 75-84 years.

CONCLUSIONS

Statin use was associated with a decreased risk of incident PAD for those under the age of 75 years. Neither race nor depression significantly modified the relationship between statin use and incident PAD; however, the risk of incident PAD was lower among Black Americans. These findings highlight that the benefit of statin may wane for those over the age of 75 years. Findings also suggest that statin use may not be compromised in those living with depression.

Non-coronary peripheral arterial complications in people with type 2 diabetes: a Swedish retrospective cohort study

Background

Few studies have explored long-term trends and risk factors for peripheral arterial complications in type 2 diabetes compared to the general population. Our research focuses on identifying optimal risk factors, their significance, risk associated with multifactorial risk factor control, and trends for these complications in diabetic patients versus general controls.

Methods

This study included persons with type 2 diabetes mellitus entered into the Swedish National Diabetes Register 2001-2019 and controls matched for age-, sex- and county of residence. Outcomes comprised of extracranial large artery disease, aortic aneurysm, aortic dissection, lower extremity arterial disease and diabetes foot disease. Standardized incidence rates and Cox regression were used for analyses.

Findings

The study comprises 655,250 persons with type 2 diabetes mellitus; average age 64.2; 43.8% women. Among persons with type 2 diabetes mellitus, the incidence rates per 100,000 person years for each non-coronary peripheral arterial complication event changed between 2001 and 2019 as follows: extracranial large artery disease 170.0-84.9; aortic aneurysm 40.6-69.2; aortic dissection 9.3 to 5.6; lower extremity artery disease from 338.8 to 190.8; and diabetic foot disease from 309.8 to 226.8. Baseline hemoglobin A1c (HbA1c), systolic blood pressure (SBP), smoking status and lipid levels were independently associated with all outcomes in the type 2 diabetes mellitus cohort. Within the cohort with type 2 diabetes mellitus, the risk for extracranial large artery disease and lower extremity artery disease increased in a stepwise fashion for each risk factor not within target. Excess risk for non-coronary peripheral arterial complications in the entire cohort for persons with type 2 diabetes mellitus, compared to matched controls, were as follows: extracranial large artery disease adjusted hazard ratio (HR) 1.69 (95% confidence interval (CI), 1.65-1.73), aortic aneurysm HR 0.89 (95% CI, 0.87-0.92), aortic dissection HR 0.51 (95% CI, 0.46-0.57) and lower extremity artery disease HR 2.59 (95% CI, 2.55-2.64).

Interpretation

The incidence of non-coronary peripheral arterial complications has declined significantly among persons with type 2 diabetes mellitus, with the exception of aortic aneurysm. HbA1c, smoking and blood pressure demonstrated greatest relative contribution for outcomes and lower levels of cardiometabolic risk factors are associated with reduced relative risk of outcomes.

Funding

Swedish Governmental and the County support of research and education of doctors, the Swedish Heart-Lung Foundation and Åke-Wibergs grant.

Pedal medial arterial calcification in diabetic foot ulcers: A significant risk factor of amputation and mortality

AIMS

Pedal medial arterial calcification (MAC) is frequently observed in individuals with diabetic foot ulcers (DFUs). However, the impact of pedal MAC on individuals with DFUs remains uncertain. The main aim of this study was to evaluate the association between pedal MAC with amputation and mortality outcomes.

METHODS

A prospective, observational cohort study was conducted at West China Hospital from January 2012 to December 2021. Logistic regression analyses, Kaplan-Meier survival method, and Cox proportional hazards models were employed to evaluate the relationship between pedal MAC and amputation as well as mortality.

RESULTS

A total of 979 patients were enrolled in the study. Peripheral artery disease (PAD) was observed in 53% of patients with DFUs, and pedal MAC was found in 8%. Over a median follow-up of 46 (23-72) months, foot amputation was performed on 190 patients, and mortality occurred in 246 patients. Pedal MAC showed a significant association with amputation both in unadjusted analysis (odds ratio [OR] = 2.98, 95% confidence interval [CI] = 1.86-4.76, p < .001) and after adjusting sex, age, albumin levels, hemoglobin levels, and diabetic retinopathy status (OR 2.29, 95% CI 1.33-3.93, p = .003). The risk of amputation was found to be twofold higher in individuals with PAD and pedal MAC compared to those with PAD alone (OR 2.05, 95% CI 1.10-3.82, p = .024). Furthermore, the presence of pedal MAC was significantly associated with an increased risk of mortality (p = .005), particularly among individuals with DFUs but without PAD (HR 4.26, 95% CI 1.90-9.52, p < .001), rather than in individuals presenting with both DFUs and PAD.

CONCLUSION

The presence of pedal MAC is significantly associated with both amputation and mortality in individuals with DFUs. Moreover, pedal MAC could provide additional value to predict amputation other than PAD.

Comparison of Postoperative Complications in Patients Undergoing Limb Salvage Reconstructive Surgery Based on Estimated Prevalence of Preexisting Peripheral Arterial Disease

BACKGROUND

Limb salvage after lower extremity (LE) trauma requires optimal blood flow for successful microsurgical reconstruction. Peripheral arterial disease (PAD) decreases LE perfusion, affecting wound healing. Patients who present with LE trauma may have undiagnosed PAD, particularly those with atherosclerotic risk factors. This study assesses outcomes after LE salvage in patients at risk for PAD.

METHODS

This retrospective review evaluated patients who underwent LE reconstruction at a level 1 trauma center between 2007 and 2022. Patients with a nontraumatic mechanism of injury, missing postoperative records, and unspecified race were excluded. Demographics, flap characteristics, and postoperative complications were abstracted. The prevalence of LE PAD was calculated using a validated risk assessment tool.

RESULTS

At our institution, 285 LE flaps performed on 254 patients were included in the study. Patients were categorized by prevalence of PAD, including 12 (4.7%) with high risk, 45 (17.7%) with intermediate risk, and 197 (77.6%) patients with low risk. The high-risk cohort had higher rates of partial flap necrosis ( P = 0.037), flap loss ( P = 0.006), and amputation ( P < 0.001) compared with the low-risk group. Fewer high-risk patients achieved full ambulation compared with the low-risk ( P = 0.005) cohort. Overall flap survival and limb salvage rates were 94.5% and 96.5%, respectively. Among the intermediate- and high-risk cohorts, only 50.9% of patients received a preoperative vascular assessment, and 3.8% received a vascular surgery consultation.

CONCLUSIONS

Peripheral arterial disease represents a reconstructive challenge to microvascular surgeons. Patients with high-risk for PAD had higher rates of partial flap necrosis, flap loss, and amputation. In the setting of trauma, emphasis should be placed on preoperative vascular assessment for patients at risk of having undiagnosed PAD. Prospective studies collecting ankle-brachial index assessments and/or angiography will help validate this study's findings.

Identifying the highest risk vascular patients: Insights from the XATOA registry

BACKGROUND

Patients with coronary and peripheral artery disease (PAD) have a residual risk of major adverse cardiovascular and limb events despite standards of care. Among patients with coronary artery disease (CAD) and/or PAD selected for low dose rivaroxaban (2.5 mg BID) and aspirin, we sought to determine the highest risk vascular patients.

METHODS

Xarelto pluc Acetylsalicylic acid: Treatment patterns and Outcomes in patients with Atherosclerosis (XATOA) is a single-arm registry of CAD and/or PAD patients. All participants were initiated on low dose rivaroxaban (2.5 mg BID) and aspirin. We report the incidence risk of major adverse cardiovascular events (MACE) or major adverse limb events (MALE) and major bleeding. A classification and regression tree analysis determined independent subgroups.

RESULTS

Between November 2018 and May 2020, 5,808 participants were enrolled in XATOA; 5,532 were included in the full analysis. The median follow-up (interquartile range) was 462 (371-577) days. The incidence risk per 100 patient-years of MACE or MALE was highest among participants with polyvascular disease (2 or more vascular beds affected, n = 2,889). The incidence risk was 9.16 versus 2.48 per 100 patient-years in polyvascular and nonpolyvascular patients respectively. Other subgroups of high-risk patients included participants 75 years or older, with a history of diabetes, heart failure, or chronic renal insufficiency (CRI). Rates of major bleeding were low overall. A classification and regression tree analysis showed that polyvascular disease was the most dominant factor separating higher from lower risk participants, and this was heightened with CRI or diabetes.

CONCLUSION

Patients with polyvascular disease represent a substantial subset of patients in clinical practice and should be prioritized to receive maximal medical therapy including low dose rivaroxaban (2.5 mg BID) and aspirin.

Can acupuncture increase microcirculation in peripheral artery disease and diabetic foot syndrome? - a pilot study

Background

Globally, diabetes mellitus (DM) and peripheral artery disease (PAD) have an increasing incidence and a high prevalence and are both associated with high morbidity and complication rates, e.g., as chronic non-healing peripheral ulcers. Impaired macro- and microcirculation and peripheral neuropathy lead to an increased risk of foot ulcers and infections. These complications are difficult to treat, have a high risk of becoming chronic and often lead to lower limb amputation. The aim of this planned study was to investigate the potential effects of acupuncture on improving microcirculation in patients with Diabetic Foot Syndrome (DFS) and PAD.

Materials and methods

In 18 patients with chronic non-healing peripheral ulcers and diagnosed DM or PAD, data on 8 microcirculatory parameters were collected simultaneously on intact skin close to the wound margin. Microcirculation was assessed using an O2C device combining laser Doppler shift and white light spectroscopy (LEA Medizintechnik GmbH, Giessen, Germany). Unilateral and bilateral acupuncture was performed on the connecting line between acupuncture points Stomach 14 and Stomach 15.

Results

After unilateral acupuncture (ipsilateral to the wound side), a statistically significant improvement in 7 out of 8 microcirculatory parameters was demonstrated compared to baseline measurements before acupuncture. After bilateral acupuncture, there was an additional improvement and statistical significance in all parameters in both DFS and PAD patients.

Discussion

These results show an improvement in the microcirculation and peripheral blood flow at the edges of the wound. As impaired micro- and macrocirculation is considered to be a critical prognostic factor for the healing of a peripheral lesion, the intervention could have a positive impact on the healing of (chronic) peripheral wounds.

2024 Heart Disease and Stroke Statistics: A Report of US and Global Data From the American Heart Association

BACKGROUND

The American Heart Association (AHA), in conjunction with the National Institutes of Health, annually reports the most up-to-date statistics related to heart disease, stroke, and cardiovascular risk factors, including core health behaviors (smoking, physical activity, nutrition, sleep, and obesity) and health factors (cholesterol, blood pressure, glucose control, and metabolic syndrome) that contribute to cardiovascular health. The AHA Heart Disease and Stroke Statistical Update presents the latest data on a range of major clinical heart and circulatory disease conditions (including stroke, brain health, complications of pregnancy, kidney disease, congenital heart disease, rhythm disorders, sudden cardiac arrest, subclinical atherosclerosis, coronary heart disease, cardiomyopathy, heart failure, valvular disease, venous thromboembolism, and peripheral artery disease) and the associated outcomes (including quality of care, procedures, and economic costs).

METHODS

The AHA, through its Epidemiology and Prevention Statistics Committee, continuously monitors and evaluates sources of data on heart disease and stroke in the United States and globally to provide the most current information available in the annual Statistical Update with review of published literature through the year before writing. The 2024 AHA Statistical Update is the product of a full year's worth of effort in 2023 by dedicated volunteer clinicians and scientists, committed government professionals, and AHA staff members. The AHA strives to further understand and help heal health problems inflicted by structural racism, a public health crisis that can significantly damage physical and mental health and perpetuate disparities in access to health care, education, income, housing, and several other factors vital to healthy lives. This year's edition includes additional global data, as well as data on the monitoring and benefits of cardiovascular health in the population, with an enhanced focus on health equity across several key domains.

RESULTS

Each of the chapters in the Statistical Update focuses on a different topic related to heart disease and stroke statistics.

CONCLUSIONS

The Statistical Update represents a critical resource for the lay public, policymakers, media professionals, clinicians, health care administrators, researchers, health advocates, and others seeking the best available data on these factors and conditions.

Endothelial Senescence: From Macro- to Micro-Vasculature and Its Implications on Cardiovascular Health

Endothelial cells line at the most inner layer of blood vessels. They act to control hemostasis, arterial tone/reactivity, wound healing, tissue oxygen, and nutrient supply. With age, endothelial cells become senescent, characterized by reduced regeneration capacity, inflammation, and abnormal secretory profile. Endothelial senescence represents one of the earliest features of arterial ageing and contributes to many age-related diseases. Compared to those in arteries and veins, endothelial cells of the microcirculation exhibit a greater extent of heterogeneity. Microcirculatory endothelial senescence leads to a declined capillary density, reduced angiogenic potentials, decreased blood flow, impaired barrier properties, and hypoperfusion in a tissue or organ-dependent manner. The heterogeneous phenotypes of microvascular endothelial cells in a particular vascular bed and across different tissues remain largely unknown. Accordingly, the mechanisms underlying macro- and micro-vascular endothelial senescence vary in different pathophysiological conditions, thus offering specific target(s) for therapeutic development of senolytic drugs.

An exercise stress test for contrast-enhanced duplex ultrasound assessment of lower limb muscle perfusion in patients with peripheral arterial disease

OBJECTIVE

The aim of the present study was to develop a standardized contrast-enhanced duplex ultrasound (CE-DUS) protocol to assess lower-extremity muscle perfusion before and after exercise and determine relationships of perfusion with clinical and functional measures.

METHODS

CE-DUS (EPIQ 5G, Philips) was used before and immediately after a 10-minute, standardized bout of treadmill walking to compare microvascular perfusion of the gastrocnemius muscle in older (55-82 years) patients with peripheral arterial disease (PAD) (n = 15, mean ankle-brachial index, 0.78 ± 0.04) and controls (n = 13). Microvascular blood volume (MBV) and microvascular flow velocity (MFV) were measured at rest and immediately following treadmill exercise, and the Modified Physical Performance Test (MPPT) was used to assess mobility function.

RESULTS

In the resting state (pre-exercise), MBV in patients with PAD was not significantly different than normal controls (5.17 ± 0.71 vs 6.20 ± 0.83 arbitrary units (AU) respectively; P = .36); however, after exercise, MBV was ∼40% lower in patients with PAD compared with normal controls (5.85 ± 1.13 vs 9.53 ± 1.31 AU, respectively; P = .04). Conversely, MFV was ∼60% higher in patients with PAD compared with normal controls after exercise (0.180 ± 0.016 vs 0.113 ± 0.018 AU, respectively; P = .01). There was a significant between-group difference in the exercise-induced changes in both MBV and MFV (P ≤ .05). Both basal and exercise MBV directly correlated with MPPT score in the patients with PAD (r = 0.56-0.62; P < .05).

CONCLUSIONS

This standardized protocol for exercise stress testing of the lower extremities quantifies calf muscle perfusion and elicits perfusion deficits in patients with PAD. This technique objectively quantifies microvascular perfusion deficits that are related to reduced mobility function and could be used to assess therapeutic efficacy in patients with PAD.

Examining Outcomes in Patients Admitted With Comorbid Peripheral Artery Disease and Microvascular Disease

BACKGROUND

Peripheral artery disease (PAD) and microvascular disease (MVD) are highly prevalent conditions that share common risk factors. This observational study aimed to characterize patients with both conditions and determine the impact of comorbid PAD/MVD on outcomes.

METHODS AND RESULTS

Patients admitted across 31 states January 2011 through December 2018 with a primary or secondary diagnosis of PAD or MVD were included from the National Readmissions Database and weighted to approximate a national sample. Those age <18 years or with nonatherosclerotic leg injuries were excluded. Patients were divided into 3 groups: PAD-only, MVD-only, or comorbid PAD/MVD. Multiple logistic regression was used to evaluate associations with major and minor amputations, major adverse cardiac events, and in-hospital mortality. Cox regression was used to evaluate associations with readmission within 1 year. The PAD group was used as reference. The final cohort included 33 972 772 admissions: 9.1 million with PAD, 21.3 million with MVD, and 3.6 million with both. Annual admissions for PAD/MVD increased to >500 000 in 2018. Major and minor amputations increased ≈50% for PAD/MVD between 2011 and 2018. Compared with PAD-only, PAD/MVD was associated with a higher risk for major amputation (odds ratio [OR], 1.30 [95% CI, 1.28-1.32]), minor amputation (OR, 2.15 [95% CI, 2.12-2.18]), major adverse cardiac events (OR, 1.04 [95% CI, 1.03-1.04]), in-hospital mortality (OR, 1.07 [95% CI, 1.05-1.09]), and readmission (hazard ratio, 1.02 [95% CI, 1.02-1.02]) after adjustment for baseline factors.

CONCLUSIONS

Comorbid MVD is present in a large and growing number of patients with PAD and is associated with augmented risk for adverse outcomes. Further prospective research is merited to understand this vulnerable population.

10. Cardiovascular Disease and Risk Management: Standards of Care in Diabetes-2024

The American Diabetes Association (ADA) "Standards of Care in Diabetes" includes the ADA's current clinical practice recommendations and is intended to provide the components of diabetes care, general treatment goals and guidelines, and tools to evaluate quality of care. Members of the ADA Professional Practice Committee, an interprofessional expert committee, are responsible for updating the Standards of Care annually, or more frequently as warranted. For a detailed description of ADA standards, statements, and reports, as well as the evidence-grading system for ADA's clinical practice recommendations and a full list of Professional Practice Committee members, please refer to Introduction and Methodology. Readers who wish to comment on the Standards of Care are invited to do so at professional.diabetes.org/SOC.

Deletion of the aryl hydrocarbon receptor in endothelial cells improves ischemic angiogenesis in chronic kidney disease

Chronic kidney disease (CKD) is a strong risk factor for peripheral artery disease (PAD) that is associated with worsened clinical outcomes. CKD leads to the accumulation of tryptophan metabolites that are associated with adverse limb events in PAD and are ligands of the aryl hydrocarbon receptor (AHR), which may regulate ischemic angiogenesis. To test if endothelial cell-specific deletion of the AHR (AHRecKO) alters ischemic angiogenesis and limb function in mice with CKD subjected to femoral artery ligation. Male AHRecKO mice with CKD displayed better limb perfusion recovery and enhanced ischemic angiogenesis compared with wild-type mice with CKD. However, the improved limb perfusion did not result in better muscle performance. In contrast to male mice, deletion of the AHR in female mice with CKD had no impact on perfusion recovery or angiogenesis. With the use of primary endothelial cells from male and female mice, treatment with indoxyl sulfate uncovered sex-dependent differences in AHR activating potential and RNA sequencing revealed wide-ranging sex differences in angiogenic signaling pathways. Endothelium-specific deletion of the AHR improved ischemic angiogenesis in male, but not female, mice with CKD. There are sex-dependent differences in Ahr activating potential within endothelial cells that are independent of sex hormones.NEW & NOTEWORTHY This study provides novel insights into the mechanisms by which chronic kidney disease worsens ischemic limb outcomes in an experimental model of peripheral artery disease. Deletion of the aryl hydrocarbon receptor (AHR) in the endothelium improved ischemic angiogenesis suggesting that AHR inhibition could be a viable therapeutic target; however, this effect was only observed in male mice. Subsequent analysis in primary endothelial cells reveals sex differences in Ahr activating potential independent of sex hormones.

Blood Oxygen Level-Dependent MR Imaging of Lower Extremities in Peripheral Artery Disease and Its Correlation With Walking Performance

BACKGROUND

A noninvasive and reliable approach to quantitatively measure muscle perfusion of lower extremity is needed to aid the diagnosis and treatment of peripheral artery disease (PAD).

PURPOSE

To verify the reproductivity of using blood oxygen level-dependent (BOLD) imaging to evaluate perfusion in lower extremities, and explore its correlation with walking performance in patients with PAD.

STUDY TYPE

Prospective observational study.

SUBJECTS

Seventeen patients with lower extremity PAD (mean age: 67 ± 6 years, 15 males) and eight older adults (controls).

FIELD STRENGTH/SEQUENCE

Dynamic multi-echo gradient echo T2* weighted imaging at 3T.

ASSESSMENT

Perfusion was analyzed in regions of interest according to muscle groups. Perfusion parameters were measured, such as minimum ischemia value (MIV), time to peak (TTP), and gradient during reactive hyperemia (Grad) by two independent users. Walking performance experiments including short physical performance battery (SPPB) and 6-minute walk were tested in patients.

STATISTICAL TESTS

BOLD parameters were compared using Mann-Whitney U test and Kruskal-Wallis test. Relations between parameters and walking performance were assessed by Mann-Whitney U test and Spearman's correlation coefficient.

RESULTS

Good to perfect agreement was demonstrated for all perfusion parameters of interuser reproducibility, and the interscan reproducibility of MIV, TTP, and Grad was good. The TTP of the patients was longer than that of the controls (87.85 ± 38.85 s vs. 36.54 ± 7.27 s), while the Grad of patients was smaller (0.16 ± 0.12 msec/s vs. 0.24 ± 0.11 msec/s). Among PAD patients, the MIV was significantly lower in the low SPPB subgroup (score 6-8) than in the high SPPB group (score 9-12), and the TTP was negatively correlated with 6-minute walk distance (ρ = -0.549).

DATA CONCLUSION

BOLD imaging method had overall good reproducibility for the perfusion assessment of calf muscles. The perfusion parameters were different between PAD patients and controls, and were correlated with lower extremity function.

EVIDENCE LEVEL

2 TECHNICAL EFFICACY: Stage 2.

Therapeutic Potential for Beta-3 Adrenoreceptor Agonists in Peripheral Arterial Disease and Diabetic Foot Ulcers

Annually, peripheral arterial disease is estimated to cost over USD 21 billion and diabetic foot disease an estimated at USD 9-13 billion. Mirabegron is a TGA-approved beta-3 adrenoreceptor agonist, shown to be safe and effective in the treatment of overactive bladder syndrome by stimulating bladder smooth muscle relaxation. In this review, we discuss the potential use of beta-3 adrenoreceptor agonists as therapeutic agents repurposed for peripheral arterial disease and diabetic foot ulcers. The development of both conditions is underpinned by the upregulation of oxidative stress pathways and consequential inflammation and hypoxia. In oxidative stress, there is an imbalance of reactive oxygen species and nitric oxide. Endothelial nitric oxide synthase becomes uncoupled in disease states, producing superoxide and worsening oxidative stress. Agonist stimulation of the beta-3 adrenoreceptor recouples and activates endothelial nitric oxide synthase, increasing the production of nitric oxide. This reduces circulating reactive oxygen species, thus decreasing redox modification and dysregulation of cellular proteins, causing downstream smooth muscle relaxation, improved endothelial function and increased angiogenesis. These mechanisms lead to endothelial repair in peripheral arterial disease and an enhanced perfusion in hypoxic tissue, which will likely improve the healing of chronic ulcers.

Incidence, Microbiological Studies, and Factors Associated With Prosthetic Joint Infection After Total Knee Arthroplasty

Importance

Despite the frequency of total knee arthroplasty (TKA) and clinical implications of prosthetic joint infections (PJIs), knowledge gaps remain concerning the incidence, microbiological study results, and factors associated with these infections.

Objectives

To identify the incidence rates, organisms isolated from microbiological studies, and patient and surgical factors of PJI occurring early, delayed, and late after primary TKA.

Design, Setting, and Participants

This cohort study obtained data from the US Department of Veterans Affairs (VA) Corporate Data Warehouse on patients who underwent elective primary TKA in the VA system between October 1, 1999, and September 30, 2019, and had at least 1 year of care in the VA prior to TKA. Patients who met these criteria were included in the overall cohort, and patients with linked Veterans Affairs Surgical Quality Improvement Program (VASQIP) data composed the VASQIP cohort. Data were analyzed between December 9, 2021, and September 18, 2023.

Exposures

Primary TKA as well as demographic, clinical, and perioperative factors.

Main Outcomes and Measures

Incident hospitalization with early, delayed, or late PJI. Incidence rate (events per 10 000 person-months) was measured in 3 postoperative periods: early (≤3 months), delayed (between >3 and ≤12 months), and late (>12 months). Unadjusted Poisson regression was used to estimate incidence rate ratios (IRRs) with 95% CIs of early and delayed PJI compared with late PJI. The frequency of organisms isolated from synovial or operative tissue culture results of PJIs during each postoperative period was identified. A piecewise exponential parametric survival model was used to estimate IRRs with 95% CIs associated with demographic and clinical factors in each postoperative period.

Results

The 79 367 patients (median (IQR) age of 65 (60-71) years) in the overall cohort who underwent primary TKA included 75 274 males (94.8%). A total of 1599 PJIs (2.0%) were identified. The incidence rate of PJI was higher in the early (26.8 [95% CI, 24.8-29.0] events per 10 000 person-months; IRR, 20.7 [95% CI, 18.5-23.1]) and delayed periods (5.4 [95% CI, 4.9-6.0] events per 10 000 person-months; IRR, 4.2 [95% CI, 3.7-4.8]) vs the late postoperative period (1.3 events per 10 000 person-months). Staphylococcus aureus was the most common organism isolated overall (489 [33.2%]); however, gram-negative infections were isolated in 15.4% (86) of early PJIs. In multivariable analyses, hepatitis C virus infection, peripheral artery disease, and autoimmune inflammatory arthritis were associated with PJI across all postoperative periods. Diabetes, chronic kidney disease, and obesity (body mass index of ≥30) were not associated factors. Other period-specific factors were identified.

Conclusions and Relevance

This cohort study found that incidence rates of PJIs were higher in the early and delayed vs late post-TKA period; there were differences in microbiological cultures and factors associated with each postoperative period. These findings have implications for postoperative antibiotic use, stratification of PJI risk according to postoperative time, and PJI risk factor modification.

The Mechanism of Effort Intolerance in Patients with Peripheral Arterial Disease: A Combined Stress Echocardiography and Cardiopulmonary Exercise Test

AIM

We used a combined stress echocardiography and cardiopulmonary exercise test (CPET) to explore effort intolerance in peripheral arterial disease (PAD) patients.

METHODS

Twenty-three patients who had both PAD and coronary artery disease (CAD) were compared with twenty-four sex- and age-matched CAD patients and fifteen normal controls using a symptom-limited ramp bicycle CPET on a tilting dedicated ergometer. Echocardiographic images were obtained concurrently with gas exchange measurements along predefined stages of exercise. Oxygen extraction was calculated using the Fick equation at each activity level.

RESULTS

Along the stages of exercise (unloaded; anaerobic threshold; peak), in PAD + CAD patients compared with CAD or controls, diastolic function worsened (p = 0.051 and p = 0.013, respectively), and oxygen consumption (p < 0.001 and p < 0.001, respectively) and oxygen pulse (p = 0.0024 and p = 0.0027, respectively) were reduced. Notably, oxygen pulse was blunted due to an insufficient increase in both stroke volume (p = 0.025 and p = 0.028, respectively) and peripheral oxygen extraction (p = 0.031 and p = 0.038, respectively). Chronotropic incompetence was more prevalent in PAD patients and persisted after correction for beta-blocker use (62% vs. 42% and 11%, respectively).

CONCLUSIONS

In PAD patients, exercise limitation is associated with diastolic dysfunction, chronotropic incompetence and peripheral factors.

Risk Factors for Lower Extremity Amputation in Patients with End-Stage Kidney Disease: A Nationwide Cohort Study

Individuals with end-stage kidney disease (ESKD) on dialysis are at a high risk of developing foot ulcerations and undergoing subsequent lower extremity amputation (LEA), which can exert significant impacts on their quality of life and contribute to rising healthcare costs. We aimed to identify risk factors associated with LEA in patients with ESKD to predict LEA progression and eventually prevent it. We used 18 years (2002-2019) of data from the Korean National Health Insurance Service (KNHIS). Data were collected from patients with ESKD who underwent renal replacement therapy (RRT) and had no history of amputation caused by trauma or toxins. The risk factors were compared between patients with or without LEA. We collected data from 220,838 patients newly diagnosed with ESKD, including 6348 in the LEA group and 214,490 in the non-LEA group. The total incidence of LEA was 2.9%. Older age, male gender, lower income, non-metropolitan residence, diabetes mellitus, dialysis treatment (compared to kidney transplantation), microvascular disease, peripheral vascular disease, endovascular procedure, and endovascular operation were associated with an increased risk of LEA. Thus, individuals with ESKD who are at a higher risk for LEA should be closely monitored, and kidney transplantation should be considered as a preventative measure.

Association between serum uric acid levels and peripheral artery disease in Chinese adults with hypertension

Background

Higher serum uric acid (SUA) can cause gout, which is principally characterized by arthritis due to monosodium urate crystal deposition in the lower extremities. High levels of SUA have been linked to endothelial dysfunction, oxidative stress, and inflammation, all of which are involved in the pathogenesis of peripheral artery disease(PAD). To date, the relationship between SUA levels and PAD is still poorly understood.

Method

An analysis of 9,839 Chinese adults with essential hypertension from the ongoing China H-type Hypertension Registry Study was conducted in this cross-sectional study. Patients with an ABI ≤0.9 was diagnosed with PAD. Hyperuricemia was defined as SUA levels >420 mol/L in men and >360 mol/L in women. The association between SUA levels and PAD was evaluated using multivariable logistic regression models based on odds ratios (ORs) and their 95% confidence intervals (CIs).

Results

The enrolled subjects ranged in age from 27 to 93 years, with a mean age of 63.14 ± 8.99 years. The proportion of male patients was 46.22%, and the prevalence of hyperuricemia was 50.72%. In males, hyperuricemia was positively associated with the risk of PAD (adjusted OR per SD increase: 1.72, 95% CI 1.17 to 2.53, P =0.006). Males in the highest SUA tertile were significantly more likely to have PAD (adjusted OR: 2.63, 95% CI 1.42 to 4.86, P = 0.002; P for trend = 0.001). However, this positive relationship was not observed in females (adjusted OR: 1.29, 95% CI 0.77 to 2.17, P = 0.327; P for trend = 0.347).

Conclusion

According to this cross-sectional study, higher SUA levels were positively associated with PAD in male hypertensive patients, while this positive relationship disappeared in female participants.

The Influence of Diabetes Mellitus on Mortality of Patients After Lower Extremity Amputation: A Systematic Review and Meta-analysis

OBJECTIVE

The influence of diabetes mellitus (DM) on mortality following lower extremity amputation (LEA) remains controversial. This systematic review and meta-analysis aimed to determine the influence of DM on long-term mortality (LTM) and short-term mortality (STM) after amputation.

MATERIALS AND METHODS

The Medline, the Cochrane library, and Embase databases were searched. The primary and secondary outcomes were LTM and STM following amputation. One-year and 30-day all-cause mortality after amputation were considered as LTM and STM, respectively. A random-effects model was utilized to pool results. To evaluate the stability of results, subgroup analyses and sensitivity analyses were conducted.

RESULTS

Twenty-three cohort studies with a total of 58,219 patients were included, among which 31,750 (54.5%) patients had DM. The mean score of included studies evaluated by Newcastle-Ottawa Scale was 7.65, indicating moderate to high quality. The pooled results showed no significant difference in 1-year LTM (risk ratio [RR], 0.96; 95% CI 0.86-1.07) after amputation. However, 3-year (RR, 1.22; 95% CI 1.01-1.47) and 5-year (RR, 1.18; 95% CI 1.07-1.31) LTMs of DM patients were obviously higher than that of NDM (non-diabetes mellitus) patients. The STM of the DM group was significantly lower than the NDM group (RR, 0.80; 95% CI 0.64-0.98).

CONCLUSIONS

The current study revealed that DM patients had an obvious lower STM following LEA, but the risk of DM on LTM after amputation was gradually increased with time. More attention should be paid to the long-term survival of DM patients after LEA.

Activation of the Aryl Hydrocarbon Receptor in Endothelial Cells Impairs Ischemic Angiogenesis in Chronic Kidney Disease

Rationale

Chronic kidney disease (CKD) is a strong risk factor for peripheral artery disease (PAD) that is associated with worsened clinical outcomes. CKD leads to accumulation of tryptophan metabolites that associate with adverse limb events in PAD and are ligands of the aryl hydrocarbon receptor (AHR) which may regulate ischemic angiogenesis.

Objectives

To test if endothelial cell-specific deletion of the AHR (AHRecKO) alters ischemic angiogenesis and limb function in mice with CKD subjected to femoral artery ligation.

Findings

Male AHRecKO mice with CKD displayed better limb perfusion recovery and enhanced ischemic angiogenesis compared to wildtype mice with CKD. However, the improved limb perfusion did not result in better muscle performance. In contrast to male mice, deletion of the AHR in female mice with CKD had no impact on perfusion recovery or angiogenesis. Using primary endothelial cells from male and female mice, treatment with indoxyl sulfate uncovered sex-dependent differences in AHR activating potential and RNA sequencing revealed wide ranging sex-differences in angiogenic signaling pathways.

Conclusion

Endothelium-specific deletion of the AHR improved ischemic angiogenesis in male, but not female, mice with CKD. There are sex-dependent differences in Ahr activating potential within endothelial cells that are independent of sex hormones.

Health Disparities in Peripheral Artery Disease: A Scientific Statement From the American Heart Association

Peripheral artery disease (PAD) affects 200 million individuals worldwide. In the United States, certain demographic groups experience a disproportionately higher prevalence and clinical effect of PAD. The social and clinical effect of PAD includes higher rates of individual disability, depression, minor and major limb amputation along with cardiovascular and cerebrovascular events. The reasons behind the inequitable burden of PAD and inequitable delivery of care are both multifactorial and complex in nature, including systemic and structural inequity that exists within our society. Herein, we present an overview statement of the myriad variables that contribute to PAD disparities and conclude with a summary of potential novel solutions.

Activation of the Aryl Hydrocarbon Receptor in Muscle Exacerbates Ischemic Pathology in Chronic Kidney Disease

BACKGROUND

Chronic kidney disease (CKD) accelerates the development of atherosclerosis, decreases muscle function, and increases the risk of amputation or death in patients with peripheral artery disease (PAD). However, the mechanisms underlying this pathobiology are ill-defined. Recent work has indicated that tryptophan-derived uremic solutes, which are ligands for AHR (aryl hydrocarbon receptor), are associated with limb amputation in PAD. Herein, we examined the role of AHR activation in the myopathy of PAD and CKD.

METHODS

AHR-related gene expression was evaluated in skeletal muscle obtained from mice and human PAD patients with and without CKD. AHRmKO (skeletal muscle-specific AHR knockout) mice with and without CKD were subjected to femoral artery ligation, and a battery of assessments were performed to evaluate vascular, muscle, and mitochondrial health. Single-nuclei RNA sequencing was performed to explore intercellular communication. Expression of the constitutively active AHR was used to isolate the role of AHR in mice without CKD.

RESULTS

PAD patients and mice with CKD displayed significantly higher mRNA expression of classical AHR-dependent genes (Cyp1a1, Cyp1b1, and Aldh3a1) when compared with either muscle from the PAD condition with normal renal function (P<0.05 for all 3 genes) or nonischemic controls. AHRmKO significantly improved limb perfusion recovery and arteriogenesis, preserved vasculogenic paracrine signaling from myofibers, increased muscle mass and strength, as well as enhanced mitochondrial function in an experimental model of PAD/CKD. Moreover, viral-mediated skeletal muscle-specific expression of a constitutively active AHR in mice with normal kidney function exacerbated the ischemic myopathy evidenced by smaller muscle masses, reduced contractile function, histopathology, altered vasculogenic signaling, and lower mitochondrial respiratory function.

CONCLUSIONS

These findings establish AHR activation in muscle as a pivotal regulator of the ischemic limb pathology in CKD. Further, the totality of the results provides support for testing of clinical interventions that diminish AHR signaling in these conditions.

Assessment of revascularization impact on microvascular oxygenation and perfusion using spatial frequency domain imaging

The microvasculature (with vessels <100 μm in diameter) plays a crucial role in tissue oxygenation, perfusion and wound healing in the lower limb. While this holds clinical significance, microvasculature evaluation in the limbs is not a standard practice. Surgical interventions focus on reestablishing blood flow in larger vessels affected by the peripheral artery disease (PAD). Nevertheless, the impact of revascularization on tissue oxygenation and perfusion in severe microvascular disease (MVD) is still unknown. We present the cases of two patients who underwent surgical revascularization for peripheral blood flow with different outcomes. Patient A had PAD, while B had PAD, severe MVD and a non-healing wound. Although both showed improvements in ankle-brachial index post-op, spatial frequency domain imaging metrics (which measure microvascular oxygenation and perfusion) remained unchanged in B, indicating a potential gap in assessing the surgical efficacy in MVD using ankle brachial index and emphasizing microcirculation evaluation in optimizing wound healing outcomes.

Chronic activation of the aryl hydrocarbon receptor in muscle exacerbates ischemic pathology in chronic kidney disease

Chronic kidney disease (CKD) accelerates the development of atherosclerosis, decreases muscle function, and increases the risk of amputation or death in patients with peripheral artery disease (PAD). However, the cellular and physiological mechanisms underlying this pathobiology are ill-defined. Recent work has indicated that tryptophan-derived uremic toxins, many of which are ligands for the aryl hydrocarbon receptor (AHR), are associated with adverse limb outcomes in PAD. We hypothesized that chronic AHR activation, driven by the accumulation of tryptophan-derived uremic metabolites, may mediate the myopathic condition in the presence of CKD and PAD. Both PAD patients with CKD and mice with CKD subjected to femoral artery ligation (FAL) displayed significantly higher mRNA expression of classical AHR-dependent genes ( Cyp1a1 , Cyp1b1 , and Aldh3a1 ) when compared to either muscle from the PAD condition with normal renal function ( P <0.05 for all three genes) or non-ischemic controls. Skeletal-muscle-specific AHR deletion in mice (AHR mKO ) significantly improved limb muscle perfusion recovery and arteriogenesis, preserved vasculogenic paracrine signaling from myofibers, increased muscle mass and contractile function, as well as enhanced mitochondrial oxidative phosphorylation and respiratory capacity in an experimental model of PAD/CKD. Moreover, viral-mediated skeletal muscle-specific expression of a constitutively active AHR in mice with normal kidney function exacerbated the ischemic myopathy evidenced by smaller muscle masses, reduced contractile function, histopathology, altered vasculogenic signaling, and lower mitochondrial respiratory function. These findings establish chronic AHR activation in muscle as a pivotal regulator of the ischemic limb pathology in PAD. Further, the totality of the results provide support for testing of clinical interventions that diminish AHR signaling in these conditions.

Peripheral arterial disease: A small and large vessel problem

Peripheral arterial disease (PAD) is one clinical manifestation of systemic atherosclerosis and is very common. Despite its prevalence, PAD remains underdiagnosed, undertreated, and understudied. The most common symptom in patients with PAD is intermittent claudication (IC), or pain in the lower extremities with walking or exertion, which is relieved after a short period of rest. Many patients with confirmed PAD are asymptomatic or have symptoms other than IC. Regardless of symptoms, patients with PAD have poor cardiovascular outcomes. PAD has largely been viewed a disease of large vessel atherosclerosis but what is becoming clear is that arterial plaques and occlusions are only one piece of the puzzle. Recent work has shown that abnormalities in the microvasculature contribute to the outcome of patients with PAD. From the perspective of the leg, limitation in blood flow is not the only problem as patients have a myriad of other problems, including muscle fibrosis, neuropathic changes, changes in the cellular respiration machinery and dysfunction of the small vessels that perfuse skeletal muscle and the supporting structures. Supervised exercise training remains one of the most effective tool to treat patients with PAD, however, the mechanisms behind its effectiveness are still being elucidated and use of structured exercise programs is not widespread. Medical therapy to treat systemic atherosclerosis is underutilized in patients with PAD. Invasive therapies are used only when patients with PAD have reached an advanced stage. While invasive strategies are effective in some patients with PAD, these strategies are costly, carry risk, and many patients are not amenable to invasive therapy. Appreciating the complex pathophysiology of PAD will hopefully spur new research and development of effective therapies for PAD.

Impact of microvascular complications on the outcomes of diabetic foot in type 2 diabetic patients with documented peripheral artery disease

PURPOSE

Microvascular disease (MVD) is associated with amputation linked to peripheral artery disease (PAD) in the general population. No study evaluated the impact of diabetic microvascular complications on the outcomes of vascular diabetic foot ulcers (DFU). The aim of the study was to investigate whether retinopathy, nephropathy, and polyneuropathy can predict the outcomes of DFU in type 2 diabetic patients with PAD.

METHODS

Three hundred and thirty-one consecutive patients with vascular DFU were enrolled and followed up for 44.1 ± 23.9 months.

RESULTS

The prevalence of retinopathy was significantly higher in subjects with ulcer persistence (45.2%; p < 0.01), minor amputation (48.9%; p < 0.001), and major amputation (57.9%; p < 0.001) than in healed patients (23.3%), and in non-survivors than in survivors (64.9 versus 20.5%; p < 0.001). The prevalence of nephropathy was significantly greater in subjects with ulcer persistence (83.9%; p < 0.01), minor amputation (86.7%; p < 0.001), and major amputation (94.7%; p < 0.001) than in those with healed DFU (64.4%), and in non-survivors than in survivors (88.3 versus 65.7%; p < 0.001). The prevalence of polyneuropathy was significantly higher in non-survivors than in survivors (76.6 versus 61.0%; p = 0.012). Multivariate analysis showed that absence of retinopathy (OR: 0.451; 95% CI: 0.250-0.815; p < 0.001) and nephropathy (OR: 0.450; 95% CI: 0.212-0.951; p = 0.036) were independently associated with healing. Moreover, retinopathy was a predictor both of minor amputation (OR: 2.291; 95% CI: 1.061-4.949; p = 0.034) and mortality (OR: 5.274; 95% CI: 2.524-11.020; p < 0.001). Polyneuropathy never entered the regression model.

CONCLUSIONS

Diabetic microvascular complications, in particular retinopathy, may predict the outcomes of vascular DFU. Longitudinal studies should confirm this finding.

Prolonged sitting and peripheral vascular function: potential mechanisms and methodological considerations

Sitting time is associated with increased risks for subclinical atherosclerosis and cardiovascular disease development, and this is thought to be partially due to sitting-induced disturbances in macro- and microvascular function as well as molecular imbalances. Despite surmounting evidence supporting these claims, contributing mechanisms to these phenomena remain largely unknown. In this review, we discuss evidence for potential mechanisms of sitting-induced perturbations in peripheral hemodynamics and vascular function and how these potential mechanisms may be targeted using active and passive muscular contraction methods. Furthermore, we also highlight concerns regarding the experimental environment and population considerations for future studies. Optimizing prolonged sitting investigations may allow us to not only better understand the hypothesized sitting-induced transient proatherogenic environment but to also enhance methods and devise mechanistic targets to salvage sitting-induced attenuations in vascular function, which may ultimately play a role in averting atherosclerosis and cardiovascular disease development.

Lower-limb peripheral arterial disease and amputations in people with diabetes: Risk factors, prognostic value and management

Lower-limb peripheral arterial disease (PAD), is a common manifestation of systemic atherosclerosis, resulting from a partial or complete obstruction of at least one lower-limb arteries. PAD is a major endemic disease with an excess risk of major cardiovascular events and death. It also leads to disability, high rates of lower-limb adverse events and non-traumatic amputation. In patients with diabetes, PAD is particularly frequent and has a worse prognosis than in patients without diabetes. The risk factors of PAD are comparable to those for cardiovascular disease. The ankle-brachial index is usually recommended to screen PAD despite its limited performance in patients with diabetes, affected by the presence of peripheral neuropathy, medial arterial calcification, incompressible arteries and infection. Toe brachial index and toe pressure emerge as alternative screening tools. The management of PAD requires strict control of cardiovascular risk factors including diabetes, hypertension and dyslipidaemia, the use of antiplatelet agents and lifestyle management, to reduce cardiovascular adverse events, but few randomized controlled trials have evaluated the benefits of these treatments in PAD. Several advances have been achieved in endovascular and surgical revascularization procedures, with obvious improvement in PAD prognosis. Further studies are required to increase our understanding of the pathophysiology of PAD and to evaluate the interest of different therapeutic strategies in the occurrence and progression of PAD in patients with diabetes. Here, we present a narrative and contemporary review to synthesize the key epidemiology findings, screening and diagnosis methods, and major therapeutic advances regarding PAD in patients with diabetes.

Moderate dose of dietary nitrate improves skeletal muscle microvascular function in patients with peripheral artery disease

Peripheral artery disease (PAD) is an atherosclerotic disease characterized by compromised lower-extremity blood flow that impairs walking ability. We showed that a moderate dose of dietary nitrate in the form of beetroot juice (BRJ, 0.11 mmol/kg) can improve macrovascular function and maximal walking distance in patients with PAD. However, its impacts on the microcirculation and autonomic nervous system have not been examined. Therefore, we investigated the impacts of this dose of dietary nitrate on skeletal muscle microvascular function and autonomic nervous system function and further related these measurements to 6-min walking distance, pain-free walking distance, and exercise recovery in patients with PAD. Patients with PAD (n = 10) ingested either BRJ or placebo in a randomized crossover design. Heart rate variability, skeletal muscle microvascular function, and 6-min walking distance were performed pre- and post-BRJ and placebo. There were significant group × time interactions (P < 0.05) for skeletal muscle microvascular function, 6-min walking distance, and exercise recovery, but no changes (P > 0.05) in heart rate variability or pain-free walking distance were noted. The BRJ group demonstrated improved skeletal muscle microvascular function (∆ 22.1 ± 7.5 %·min-1), longer 6-min walking distance (Δ 37.5 ± 9.1 m), and faster recovery post-exercise (Δ -15.3 ± 4.2 s). Furthermore, changes in skeletal muscle microvascular function were positively associated with changes in 6-min walking distance (r = 0.5) and pain-free walking distance (r = 0.6). These results suggest that a moderate dose of dietary nitrate may support microvascular function, which is related to improvements in walking distance and claudication in patients with PAD.

Prediction of outcomes in subjects with type 2 diabetes and diabetic foot ulcers in Catalonian primary care centers: a multicenter observational study

BACKGROUND

Diabetic foot and lower limb complications are an important cause of morbidity and mortality among persons with diabetes mellitus. Very few studies have been carried out in the primary care settings. The main objective was to assess the prognosis of diabetic foot ulcer (DFU) in patients from primary care centers in Catalonia, Spain, during a 12-month follow-up period.

METHODS

We included participants with type 2 diabetes and a new DFU between February 2018 and July 2019. We estimated the incidence of mortality, amputations, recurrence and healing of DFU during the follow-up period. A multivariable analysis was performed to assess the association of these outcomes and risk factors.

RESULTS

During the follow-up period, 9.7% of participants died, 12.1% required amputation, 29.2% had a DFU recurrence, and 73.8% healed. Having a caregiver, ischemia or infection were associated with higher mortality risk (hazard ratio [HR]:3.63, 95% confidence interval [CI]:1.05; 12.61, HR: 6.41, 95%CI: 2.25; 18.30, HR: 3.06, 95%CI: 1.05; 8.94, respectively). Diabetic retinopathy was an independent risk factor for amputation events (HR: 3.39, 95%CI: 1.37; 8.39). Increasing age decreased the risk for a DFU recurrence, while having a caregiver increased the risk for this event (HR: 0.97, 95%CI: 0.94; 0.99). The need for a caregiver and infection decreased the probability of DFU healing (HR: 0.57, 95%CI: 0.39; 0.83, HR: 0.64, 95%CI: 0.42; 0.98, respectively). High scores for PEDIS (≥7) or SINBAD (≥3) were associated with an increased risk for DFU recurrence and a lower probability of DFU healing, respectively.

CONCLUSIONS

We observed high morbidity among subjects with a new DFU in our primary healthcare facilities. Peripheral arterial disease, infection, and microvascular complications increased the risk of poor clinical outcomes among subjects with DFU.

Heart Disease and Stroke Statistics-2023 Update: A Report From the American Heart Association

BACKGROUND

The American Heart Association, in conjunction with the National Institutes of Health, annually reports the most up-to-date statistics related to heart disease, stroke, and cardiovascular risk factors, including core health behaviors (smoking, physical activity, diet, and weight) and health factors (cholesterol, blood pressure, and glucose control) that contribute to cardiovascular health. The Statistical Update presents the latest data on a range of major clinical heart and circulatory disease conditions (including stroke, congenital heart disease, rhythm disorders, subclinical atherosclerosis, coronary heart disease, heart failure, valvular disease, venous disease, and peripheral artery disease) and the associated outcomes (including quality of care, procedures, and economic costs).

METHODS

The American Heart Association, through its Epidemiology and Prevention Statistics Committee, continuously monitors and evaluates sources of data on heart disease and stroke in the United States to provide the most current information available in the annual Statistical Update with review of published literature through the year before writing. The 2023 Statistical Update is the product of a full year's worth of effort in 2022 by dedicated volunteer clinicians and scientists, committed government professionals, and American Heart Association staff members. The American Heart Association strives to further understand and help heal health problems inflicted by structural racism, a public health crisis that can significantly damage physical and mental health and perpetuate disparities in access to health care, education, income, housing, and several other factors vital to healthy lives. This year's edition includes additional COVID-19 (coronavirus disease 2019) publications, as well as data on the monitoring and benefits of cardiovascular health in the population, with an enhanced focus on health equity across several key domains.

RESULTS

Each of the chapters in the Statistical Update focuses on a different topic related to heart disease and stroke statistics.

CONCLUSIONS

The Statistical Update represents a critical resource for the lay public, policymakers, media professionals, clinicians, health care administrators, researchers, health advocates, and others seeking the best available data on these factors and conditions.

Diabetic Peripheral Neuropathy Associated with Foot Ulcer: One of a Kind

Significance: Diabetic peripheral neuropathy (DPN) associated with a diabetic foot ulcer (DFU) is likely to be complicated with critical factors such as biofilm infection and compromised skin barrier function of the diabetic skin. Repaired skin with a history of biofilm infection is known to be compromised in barrier function. Loss of barrier function is also observed in the oxidative stress affected diabetic and aged skin. Recent Advances: Loss of barrier function makes the skin prone to biofilm infection and cellulitis, which contributes to chronic inflammation and vasculopathy. Hyperglycemia favors biofilm formation as glucose lowering led to reduction in biofilm development. While vasculopathy limits oxygen supply, the O2 cost of inflammation is high increasing hypoxia severity. Critical Issues: The host nervous system can be inhabited by bacteria. Because electrical impulses are a part of microbial physiology, polymicrobial colonization of the host's neural circuit is likely to influence transmission of action potential. The identification of perineural apatite in diabetic patients with peripheral neuropathy suggests bacterial involvement. DPN starts in both feet at the same time. Future Directions: Pair-matched studies of DPN in the foot affected with DFU (i.e., DFU-DPN) compared with DPN in the without ulcer, and intact skin barrier function, are likely to provide critical insight that would help inform effective care strategies. This review characterizes DFU-DPN from a translational science point of view presenting a new paradigm that recognizes the current literature in the context of factors that are unique to DFU-DPN.

Pilot study of optical coherence tomography angiography-derived microvascular metrics in hands and feet of healthy and diabetic people

Optical coherence tomography angiography (OCTA) is a non-invasive, high-resolution imaging modality with growing application in dermatology and microvascular assessment. Accepted reference values for OCTA-derived microvascular parameters in skin do not yet exist but need to be established to drive OCTA into the clinic. In this pilot study, we assess a range of OCTA microvascular metrics at rest and after post-occlusive reactive hyperaemia (PORH) in the hands and feet of 52 healthy people and 11 people with well-controlled type 2 diabetes mellitus (T2DM). We calculate each metric, measure test-retest repeatability, and evaluate correlation with demographic risk factors. Our study delivers extremity-specific, age-dependent reference values and coefficients of repeatability of nine microvascular metrics at baseline and at the maximum of PORH. Significant differences are not seen for age-dependent microvascular metrics in hand, but they are present for several metrics in the foot. Significant differences are observed between hand and foot, both at baseline and maximum PORH, for most of the microvascular metrics with generally higher values in the hand. Despite a large variability over a range of individuals, as is expected based on heterogeneous ageing phenotypes of the population, the test-retest repeatability is 3.5% to 18% of the mean value for all metrics, which highlights the opportunities for OCTA-based studies in larger cohorts, for longitudinal monitoring, and for assessing the efficacy of interventions. Additionally, branchpoint density in the hand and foot and changes in vessel diameter in response to PORH stood out as good discriminators between healthy and T2DM groups, which indicates their potential value as biomarkers. This study, building on our previous work, represents a further step towards standardised OCTA in clinical practice and research.

Stratification of Microvascular Disease Severity in the Foot Using Spatial Frequency Domain Imaging

BACKGROUND

Microvascular disease (MVD) describes systemic changes in the small vessels (~100 um diameter) that impair tissue oxygenation and perfusion. MVD is a common but poorly monitored complication of diabetes. Recent studies have demonstrated that MVD: (i) is an independent risk factor for ulceration and amputation and (ii) increases risk of adverse limb outcomes synergistically with PAD. Despite the clinical relevance of MVD, microvascular evaluation is not standard in a vascular assessment.

METHODS

We evaluated 299 limbs from 153 patients seen clinically for possible lower extremity PAD. The patients were assessed by ankle brachial index (ABI), toe brachial index (TBI), and spatial frequency domain imaging (SFDI). These measurements were evaluated and compared to patient MVD status, defined by clinical diagnoses of (in ascending order of severity) no diabetes; diabetes; diabetes + neuropathy; diabetes + neuropathy + retinopathy.

RESULTS

SFDI-derived parameters HbT1 and StO2 were significantly different across the MVD groups (P < .001). A logistic regression model based on HbT1 and StO2 differentiated limbs with severe MVD (diabetes+neuropathy+retinopathy) from the larger group of limbs from patients with only diabetes (P = .001, area under the curve = 0.844). Neither ABI nor TBI significantly differentiated these populations.

CONCLUSIONS

Standard assessment of PAD using ABI and TBI are inadequate for detecting MVD in at-risk populations. SFDI-defined HbT1 and StO2 are promising tools for evaluating MVD. Prospective studies with wound-based outcomes would be useful to further evaluate the role MVD assessment could play in routine clinical evaluation of patients at risk for lower extremity complications.

Microvascular Burden and Incident Heart Failure Among Middle-Aged and Older Adults With Type 1 or Type 2 Diabetes

OBJECTIVE

To examine the association between microvascular disease (MVD) and risk of heart failure (HF) among individuals with type 1 diabetes mellitus (T1DM) or type 2 diabetes mellitus (T2DM).

RESEARCH DESIGN AND METHODS

We included 1,713 and 28,624 participants with T1DM and T2DM, respectively, from the UK Biobank who were free of HF during enrollment. MVD burden reflected by the presence of retinopathy, peripheral neuropathy, and chronic kidney disease (CKD) at baseline was prospectively evaluated for the association with incidence of HF. Hazard ratios (HRs) and 95% CIs of HF were estimated by Cox regression models adjusted for multiple traditional risk factors.

RESULTS

There were 145 and 2,515 incident cases of HF recorded among participants with T1DM and T2DM, respectively, during a median follow-up of 11.5 years. The association between the number of MVD and HF was stronger among participants with T1DM than among those with T2DM (P for interaction <0.001). Compared with participants with no MVD, those with all three MVD had an adjusted HR (95% CI) of 11.37 (5.62, 22.99) in T1DM and 3.66 (2.74, 4.88) in T2DM. In T1DM, HRs (CIs) were 2.69 (1.75, 4.14) for retinopathy, 2.11 (1.38, 3.23) for peripheral neuropathy, and 2.21 (1.53, 3.18) for CKD. The corresponding estimates in T2DM were 1.24 (1.13, 1.36), 1.63 (1.36, 1.96), and 1.73 (1.59, 1.89), respectively.

CONCLUSIONS

While a heavier burden of MVD was associated with excess risk of HF both in T1DM and T2DM, the association was evidently more pronounced in T1DM.