Peripheral arterial disease: morbidity and mortality implications

Leveraging Artificial Intelligence to Optimize the Care of Peripheral Artery Disease Patients

Peripheral artery disease is a major atherosclerotic disease that is associated with poor outcomes such as limb loss, cardiovascular morbidity, and death. Artificial intelligence (AI) has seen increasing integration in medicine, and its various applications can optimize the care of peripheral artery disease (PAD) patients in diagnosis, predicting patient outcomes, and imaging interpretation. In this review, we introduce various AI applications such as natural language processing, supervised machine learning, and deep learning, and we analyze the current literature in which these algorithms have been applied to PAD.

The Double Burden: Deciphering Chronic Limb-Threatening Ischemia in End-Stage Renal Disease

BACKGROUND

Chronic limb-threatening ischemia (CLTI) in patients with end-stage renal disease (ESRD) poses significant challenges in clinical management due to its unique pathology and poor treatment outcomes. This review calls for a tailored classification and risk assessment for these patients to guide better revascularization choices with early minor amputation as a first-line strategy in advanced stages.

METHODS

This review consolidates key findings from recent literature on CLTI in ESRD, focusing on disease mechanisms, treatment options, and patient outcomes. It evaluates the literature to clarify the decision-making process for managing CLTI in ESRD.

RESULTS

CLTI in ESRD patients often results in worse clinical outcomes, such as nonhealing wounds, increased limb loss, and higher mortality rates. While the literature reveals ongoing debates regarding the optimal revascularization method, recent retrospective studies and meta-analyses suggest potential benefits of endovascular treatment (EVT) over open bypass surgery (OB) in reducing mortality and wound complications, with comparable amputation-free survival rates.

CONCLUSIONS

The selection of revascularization methods in ESRD patients with CLTI is complex, necessitating individualized strategies. The importance of early detection and timely intervention is critical to decelerate disease progression and improve revascularization outcomes. There is a shift in these treatment strategies toward less invasive endovascular procedures, acknowledging the limitations these patients face with open revascularization surgeries. Considering early minor amputations after revascularization could prevent worse consequences, reflecting a shift in the approach to managing CLTI in ESRD patients.

A Platelet Reactivity ExpreSsion Score derived from patients with peripheral artery disease predicts cardiovascular risk

Platelets are key mediators of atherothrombosis, yet, limited tools exist to identify individuals with a hyperreactive platelet phenotype. In this study, we investigate the association of platelet hyperreactivity and cardiovascular events, and introduce a tool, the Platelet Reactivity ExpreSsion Score (PRESS), which integrates platelet aggregation responses and RNA sequencing. Among patients with peripheral artery disease (PAD), those with a hyperreactive platelet response (>60% aggregation) to 0.4 µM epinephrine had a higher incidence of the 30 day primary cardiovascular endpoint (37.2% vs. 15.3% in those without hyperreactivity, adjusted HR 2.76, 95% CI 1.5-5.1, p = 0.002). PRESS performs well in identifying a hyperreactive phenotype in patients with PAD (AUC [cross-validation] 0.81, 95% CI 0.68 -0.94, n = 84) and in an independent cohort of healthy participants (AUC [validation] 0.77, 95% CI 0.75 -0.79, n = 35). Following multivariable adjustment, PAD individuals with a PRESS score above the median are at higher risk for a future cardiovascular event (adjusted HR 1.90, CI 1.07-3.36; p = 0.027, n = 129, NCT02106429). This study derives and validates the ability of PRESS to discriminate platelet hyperreactivity and identify those at increased cardiovascular risk. Future studies in a larger independent cohort are warranted for further validation. The development of a platelet reactivity expression score opens the possibility for a personalized approach to antithrombotic therapy for cardiovascular risk reduction.

Long-term clinical efficacy of drug-coated balloon angioplasty for TASCII C/D femoropopliteal lesions in older patients with chronic limb-threatening ischemia: A retrospective study

This study aimed to evaluate the long-term clinical outcomes of drug-coated drug (DCB) angioplasty for long femoropopliteal lesions in older patients with chronic limb-threatening ischemia (CLTI). In this multi-center retrospective study, we enrolled 119 patients with CLTI due to Trans-Atlantic Inter-Society Consensus (TASCII) C/D femoropopliteal lesions who underwent DCB angioplasty. A total of 119 patients with 122 limbs (TASCII C = 67, 54.9%; TASCII D = 55, 45.1%) were enrolled. At 36-month follow-up, primary patency, assisted primary patency, secondary patency, and freedom from target lesion revascularization were 47.3%, 49.8%, 59.5%, and 62.7%, respectively, and there was a significant improvement over baseline in Rutherford class (P < .001) and ankle-brachial index measurements (P < .001). Complex target lesions (P = .017) and 1 stenosis-free outflow vessel (P = .001) were risk predictors of freedom from clinically driven target lesion revascularization. Complex target lesions (P = .044), diabetes (P = .007), and 1 stenosis-free outflow vessel (P = .003) were risk predictors of restenosis. At 2 months, the ulcer healing rate was 96.3% (26/27). At 36 months, the limb salvage and survival rates were 85.8% and 83.3%, respectively. DCB angioplasty were safe and effective for older patients with CLTI attributable to femoropopliteal TASCII C/D lesions.

Relationship of the modified Glasgow Prognostic Score with peripheral artery disease severity and procedure success in patients who had undergone endovascular treatment

OBJECTIVES

The modified Glasgow Prognostic Score (mGPS) is one type of inflammation-based index; it includes data on elevated C-reactive protein and reduced albumin content. The predictive value of mGPS for outcomes is investigated in various diseases such as cancer, heart failure, myocardial infarction, acute pulmonary embolism, and inflammatory bowel diseases. This study aimed to evaluate the link between mGPS and the severity and complexity of peripheral arterial disease (PAD) as determined by the Transatlantic Intercommunal Consensus Document (TASC-II) classification and the prediction value of mGPS for procedural success in patients undergoing endovascular treatment (EVT).

METHODS

Our study included 203 consecutive patients receiving EVT for atherosclerotic obstruction of aortoiliac, femoro-popliteal, and below-knee arteries between January 2019 and February 2020. The lesion characteristics were determined according to categories in the TASC-II. Operational failure is the inability to position the guidewire through the occluded lesion following percutaneous intervention or achieve distal perfusion following EVT.

RESULTS

In our study, we observed 136 patients (%6) with TASC A-B lesions and 67 patients (%33) with TASC C-D lesions. EVT was performed on the femoro-popliteal artery in 59.4% of the patients, on the aortoiliac artery in 30.7%, and on the below-the-knee artery in 9.9%. mGPS was an independent predictor of severe PAD (OR: 17.943, 95% CI: 5.120-62.882; p < .001) and procedural success (odds ratio: 0.004; 95% CI: 0.001-0.099; p < .001). Additionally, we identified age and the presence of a TASC D lesion as independent predictors of interventional success (OR: 0.938, 95% CI: 0.819-0.979; p: .034; OR: 0.104, 95% CI: 0.107-0.643; p: .015, respectively).

CONCLUSION

We determined that mGPS independently predicts PAD complexity and severity based on TASC-II classification; the EVT success rate is lower in patients with high mGPS.

Impact of hyper-polypharmacy due to non-cardiovascular medications on long-term clinical outcomes following endovascular treatment for lower limb artery disease: A sub-analysis of the I-PAD Nagano registry

BACKGROUND

Lower limb artery disease (LEAD) is accompanied by multiple comorbidities; however, the effect of hyperpolypharmacy on patients with LEAD has not been established. This study investigated the associations between hyperpolypharmacy, medication class, and adverse clinical outcomes in patients with LEAD.

METHODS

This study used data from a prospective multicenter observational Japanese registry. A total of 366 patients who underwent endovascular treatment (EVT) for LEAD were enrolled in this study. The primary endpoints were major adverse cardiac events (MACE), including myocardial infarction, stroke, and all-cause death.

RESULTS

Of 366 patients with LEAD, 12 with missing medication information were excluded. Of the 354 remaining patients, 166 had hyperpolypharmacy (≥10 medications, 46.9 %), 162 had polypharmacy (5-9 medications, 45.8 %), and 26 had nonpolypharmacy (<5 medications, 7.3 %). Over a 4.7-year median follow-up period, patients in the hyperpolypharmacy group showed worse outcomes than those in the other two groups (log-rank test, p < 0.001). Multivariate analysis revealed that the total number of medications was significantly associated with an increased risk of MACE (hazard ratio per medication increase 1.07, 95 % confidence interval 1.02-1.13 p = 0.012). Although an increased number of non-cardiovascular medications was associated with an elevated risk of MACE, the increase in cardiovascular medications was not statistically significant (log-rank test, p = 0.002 and 0.35, respectively).

CONCLUSIONS

Hyperpolypharmacy due to non-cardiovascular medications was significantly associated with adverse outcomes in patients with LEAD who underwent EVT, suggesting the importance of medication reviews, including non-cardiovascular medications.

Colchicine for cardiovascular and limb risk reduction in Medicare beneficiaries with peripheral artery disease: emulation of target trials

Aims

Recent evidence from randomized trials demonstrates that colchicine can reduce the risk of major adverse cardiovascular events (MACE) in patients with coronary artery disease. Colchicine's effect on lower-extremity peripheral artery disease (PAD) is not known.

Methods and results

To make inferences about the real-world effectiveness of colchicine in PAD, we emulated two target trials leveraging the variable prescribing practice of adding colchicine vs. a non-steroidal anti-inflammatory drug (NSAID) to urate-lowering therapy in patients with gout and PAD. Emulated Trial 1 compared colchicine initiators with NSAID initiators. Emulated Trial 2 compared long-term (indefinite) and short-term (3 months) treatment strategies after initiating colchicine. Eligible individuals were those continuously enrolled in Medicare receiving care at a multicentre academic health system between July 2007 and December 2019. The primary outcome for both trials was a 2 year composite of major adverse limb events (MALE), MACE, and all-cause mortality. Secondary outcomes included MALE and death, MACE and death, and individual components of the primary outcome. Inverse probability weighting was used to adjust for confounding. Percentile-based 95% confidence intervals (CIs) were estimated using non-parametric bootstrapping. A total of 1820 eligible patients were included; the mean age was 77 years [standard deviation (SD) 7], 32% were female, and 9% were non-White. The mean (SD) duration of colchicine and NSAID therapy was 247 (345) and 137 (237) days, respectively. In the emulation of Trial 1, the risk of the primary composite outcome of MALE, MACE, and death at 2 years was 29.9% (95% CI 27.2%, 32.3%) in the colchicine group and 31.5% (28.3%, 34.6%) in the NSAID group, with a risk difference of -1.7% (95% CI -6.5%, 3.1%) and a risk ratio of 0.95 (95% CI 0.83, 1.07). Similar findings were noted in the emulation of Trial 2, with a risk of the primary composite outcome at 2 years of 30.7% (95% CI 23.7%, 38.1%) in the long-term colchicine group and 33.4% (95% CI 29.4%, 37.7%) in the short-term group, with a risk difference of -2.7% (95% CI -10.3%, 5.4%) and risk ratio of 0.92 (95% CI 0.70, 1.16).

Conclusion

In a real-world sample of patients with PAD and gout, estimates of the effect of colchicine were consistent across two analyses and provided no conclusive evidence that colchicine decreased the risk of adverse cardiovascular or limb events and death. The cardiovascular and limb benefits of colchicine in older, comorbid populations with PAD and advanced systematic atherosclerosis remain uncertain.

Post-stroke cognitive impairment and brain hemorrhage are augmented in hypertensive mice

Hypertension is a major risk factor for both stroke and cognitive impairment, but it is unclear whether it may specifically affect post-stroke cognitive impairment. We assessed the effect of hypertension and/or stroke on brain injury, cognitive outcome, and the brain transcriptomic profile. C57BL/6J mice (n = 117; 3-5 mo.) received s.c. infusion of either saline or angiotensin II followed by sham surgery or photothrombotic stroke targeting the prefrontal cortex seven days later. Cognitive function was assessed with the Barnes maze and RNA sequencing was used to quantify transcriptomic changes in the brain. Angiotensin II treatment produced spontaneous hemorrhaging after stroke. In the Barnes maze, hypertensive mice that received stroke surgery had an increased escape latency compared to other groups (day 3: hypertensive + stroke = 166.6 ± 6.0 s vs. hypertensive + sham = 122.8 ± 13.8 s vs. normotensive + stroke = 139.9 ± 10.1 s vs. normotensive + sham = 101.9 ± 16.7 s), consistent with impaired cognition. RNA sequencing revealed >1500 differentially expressed genes related to neuroinflammation in hypertensive + stroke vs. normotensive + stroke, which included genes associated with apoptosis, microRNAs, autophagy, anti-cognitive biomarkers and Wnt signaling. Overall, we show that the combination of hypertension and stroke resulted in greater learning impairment and brain injury.

Impact of a Quality Improvement Initiative on Medical Management of Veterans With Peripheral Artery Disease

Guideline-directed medical therapy (GDMT) for peripheral artery disease (PAD) remains severely underused. Prevention of Amputation in Veterans Everywhere (PAVE) is a screening program designed to prevent or delay major lower extremity amputation. This study aimed to determine whether diagnosis of PAD through the PAVE program improves the prescription of GDMT in veterans with asymptomatic PAD. Patients enrolled into the PAVE program from our institution from 2020 to 2021 were included. Patients with an abnormal ankle-brachial index (ABI), defined as ABI <0.9 or >1.2, were selected for further analysis. Primary outcome was adherence to GDMT, following class I and class IIa recommendations. Secondary outcomes included changes in low-density lipoprotein (LDL), blood pressure, and hemoglobin A1c (HbA1c). A total of 6,313 patients were enrolled into the PAVE program between 2020 and 2021. Of these, 211 had abnormal ABI and were included in our analysis. With enrollment into PAVE, there was significant increase in the prescription of aspirin (74.4% vs 64.9%, p = 0.044) and statins (91.5% vs 82%, p = 0.006). The overall adherence to GDMT significantly increased (56.9% vs 38.9%, p <0.001). The number of patients needed to enroll in PAVE to improve GDMT adherence is 5.6 (95% confidence interval 3.6 to 12.3). Patients enrolled into PAVE program saw significant decreases in HbA1c, with mean decrease of 0.3 (p = 0.012) and a decrease in LDL, with a mean decrease of 6.2 (p = 0.01). In conclusion, enrollment into an amputation prevention program secondarily increased adherence to GDMT, driven by increases in the prescription of statins and aspirin, with resulting decreases in HbA1c and LDL.

Remnant Cholesterol, Not LDL Cholesterol, Explains Peripheral Artery Disease Risk Conferred by apoB: A Cohort Study

BACKGROUND

Elevated apoB-containing lipoproteins (=remnants+LDLs [low-density lipoproteins]) are a major risk factor for atherosclerotic cardiovascular disease, including peripheral artery disease (PAD) and myocardial infarction. We tested the hypothesis that remnants and LDL both explain part of the increased risk of PAD conferred by elevated apoB-containing lipoproteins. For comparison, we also studied the risk of chronic limb-threatening ischemia and myocardial infarction.

METHODS

apoB, remnant cholesterol, and LDL cholesterol were measured in 93 461 individuals without statin use at baseline from the Copenhagen General Population Study (2003-2015). During up to 15 years of follow-up, 1207 had PAD, 552 had chronic limb-threatening ischemia, and 2022 had myocardial infarction in the Danish National Patient Registry. Remnant and LDL cholesterol were calculated from a standard lipid profile. Remnant and LDL particle counts were additionally measured with nuclear magnetic resonance spectroscopy in 25 347 of the individuals. Results were replicated in 302 167 individuals without statin use from the UK Biobank (2004-2010).

RESULTS

In the Copenhagen General Population Study, multivariable adjusted hazard ratios for risk of PAD per 1 mmol/L (39 mg/dL) increment in remnant and LDL cholesterol were 1.9 (95% CI, 1.5-2.4) and 1.1 (95% CI, 1.0-1.2), respectively; corresponding results in the UK Biobank were 1.7 (95% CI, 1.4-2.1) and 0.9 (95% CI, 0.9-1.0), respectively. In the association from elevated apoB to increased risk of PAD, remnant and LDL cholesterol explained 73% (32%-100%) and 8% (0%-46%), respectively; corresponding results were 63% (30%-100%) and 0% (0%-33%) for risk of chronic limb-threatening ischemia and 41% (27%-55%) and 54% (38%-70%) for risk of myocardial infarction; results for remnant and LDL particle counts corroborated these findings.

CONCLUSIONS

PAD risk conferred by elevated apoB-containing lipoproteins was explained mainly by elevated remnants, while myocardial infarction risk was explained by both elevated remnants and LDL.

Prevalence and Associations of Peripheral Arterial Disease in China: The Beijing Eye Study

PURPOSE

To explore the prevalence and associations of peripheral arterial disease (PAD) in China.

DESIGN

Population-based incidence estimate and cross-sectional study.

METHODS

The participants (n=3468) of the Beijing Eye Study underwent a detailed ophthalmologic and systemic examination including assessment of the ankle-brachial index (ABI). PAD was defined by an ABI of less than 0.9.

RESULTS

Blood pressure measurements of both arms and ankles were available for 1078 (31.1%) individuals. An ABI (mean: 1.09±0.11; median: 1.10; range: 0.25, 1.36) of <0.9 and <0.95 was found in 32 of 1078 participants (3.0%, 95% CI 2.0, 4.0) and 70 of 1078 individuals (6.5%, 95% CI 5.0, 8.0), respectively. Higher PAD prevalence (multivariable analysis) was associated with older age (odds ratio [OR] 1.08, 95% CI 1.02, 1.15; P = .009), lower level of education (OR 0.62, 95% CI 0.43, 0.90; P = .01), lower quality of life (OR 0.67, 95% CI 1.11, 2.32), higher glucose serum concentration (OR 1.36, 95% CI 1.09, 1.58; P = .006), lower estimated glomerular filtration rate (OR 0.98, 95% CI 0.96, 0.99; P = .04), and higher prevalence of retinal vein occlusions (OR 7.30, 95% CI 1.63, 32.6; P = .009). PAD prevalence was not associated with the prevalence of glaucoma (P = .53) (open-angle glaucoma: P = .42; angle-closure glaucoma: P = .57) and age-related macular degeneration (any AMD: P = .39; early AMD: P = .31; intermediate AMD: P = .92; late AMD: P = .99), prevalence (P = .26) and stage (P = .07) of diabetic retinopathy, prevalence (P = .38) and degree (P = .68) of nuclear cataract, prevalence (P = .39) and degree (P = .72) of cortical cataract, prevalence of subcapsular cataract (P = .86), prevalence of pseudoexfoliation (P = .65), intraocular pressure (P = .50), axial length (P = .56), and peripapillary retinal nerve fiber layer thickness (P = .68).

CONCLUSIONS

The PAD prevalence (3.0%, 95% CI 2.0%, 4.0%) was relatively low in this cohort from rural and urban Beijing, with older age, lower educational level, lower quality of life, higher glucose serum concentration, lower estimated glomerular filtration rate, and higher prevalence of retinal vein occlusions as main associated factors.

Risk Factors for Ankle Brachial Index and Carotid Artery Stenosis in Patients with Type 2 Diabetes

Type 2 diabetes mellitus (T2DM) significantly increases the risk of atherosclerotic cardiovascular disease. Ankle brachial index (ABI) and carotid artery stenosis are non-invasive indicators of generalized atherosclerosis. This study aimed to explore the risk factors for ABI and carotid artery stenosis and discover which factors simultaneously influence both conditions in T2DM. The study included a total of 101 patients with T2DM. ABI was performed via Doppler ultrasound, and both common carotid arteries were examined via ultrasound to obtain the percentage of carotid artery stenosis. A negative correlation was noted between the ABI and the percentage of carotid artery stenosis (p = 0.043). ABI correlated significantly negatively with waist circumference (p = 0.031), total cholesterol (p = 0.003), low-density lipoprotein (LDL) cholesterol (p = 0.003), and C-reactive protein (CRP) (p = 0.017), whereas the percentage of carotid artery stenosis correlated with the smoking habit (p = 0.017) and CRP (p = 0.042). The best model for predicting the ABI value (R2 = 0.195) obtained from stepwise regression analysis included waist circumference, LDL cholesterol, triglycerides, and CRP, while the best model for the percentage of the carotid artery stenosis (R2 = 0.112) included smoking and CRP. CRP influenced the ABI value with a negative parameter estimate of -0.008962 (p = 0.053) and the percentage of the carotid artery stenosis with a positive parameter estimate of 0.443655 (p = 0.006) relative to a one-unit change of it, presenting the negatively significant impact of CRP on the association between carotid artery stenosis and low ABI. Our results suggest that CRP is the most important risk factor that connects ABI and carotid artery stenosis, which are important non-invasive indicators of generalized atherosclerosis in T2DM.

Tailored risk assessment and forecasting in intermittent claudication

BACKGROUND

Guidelines recommend cardiovascular risk reduction and supervised exercise therapy as the first line of treatment in intermittent claudication, but implementation challenges and poor patient compliance lead to significant variation in management and therefore outcomes. The development of a precise risk stratification tool is proposed through a machine-learning algorithm that aims to provide personalized outcome predictions for different management strategies.

METHODS

Feature selection was performed using the least absolute shrinkage and selection operator method. The model was developed using a bootstrapped sample based on patients with intermittent claudication from a vascular centre to predict chronic limb-threatening ischaemia, two or more revascularization procedures, major adverse cardiovascular events, and major adverse limb events. Algorithm performance was evaluated using the area under the receiver operating characteristic curve. Calibration curves were generated to assess the consistency between predicted and actual outcomes. Decision curve analysis was employed to evaluate the clinical utility. Validation was performed using a similar dataset.

RESULTS

The bootstrapped sample of 10 000 patients was based on 255 patients. The model was validated using a similar sample of 254 patients. The area under the receiver operating characteristic curves for risk of progression to chronic limb-threatening ischaemia at 2 years (0.892), risk of progression to chronic limb-threatening ischaemia at 5 years (0.866), likelihood of major adverse cardiovascular events within 5 years (0.836), likelihood of major adverse limb events within 5 years (0.891), and likelihood of two or more revascularization procedures within 5 years (0.896) demonstrated excellent discrimination. Calibration curves demonstrated good consistency between predicted and actual outcomes and decision curve analysis confirmed clinical utility. Logistic regression yielded slightly lower area under the receiver operating characteristic curves for these outcomes compared with the least absolute shrinkage and selection operator algorithm (0.728, 0.717, 0.746, 0.756, and 0.733 respectively). External calibration curve and decision curve analysis confirmed the reliability and clinical utility of the model, surpassing traditional logistic regression.

CONCLUSION

The machine-learning algorithm successfully predicts outcomes for patients with intermittent claudication across various initial treatment strategies, offering potential for improved risk stratification and patient outcomes.

Anatomical Distribution Patterns of Peripheral Arterial Disease in the Upper Extremities According to Patient Characteristics: A Retrospective Cohort Study

Purpose

Peripheral arterial disease (PAD) greatly affects the patients' quality of life. We aimed to investigate the affected anatomical sites and distribution patterns in upper extremity PAD using computed tomography angiography (CTA). Furthermore, we sought to identify the correlations between patient characteristics and the identified patterns.

Patients and Methods

This was a retrospective chart review of upper limb CTA findings from patients with symptomatic PAD aged >18 years. Significant variables from univariate logistic regression analysis were further tested using multivariate logistic regression analysis. Statistical significance was set at p < 0.05, with confidence intervals of 95%.

Results

The mean age of the 102 included patients with upper extremity PAD was 55.45 years. Laterality analysis revealed that the upper left limb segments were more affected than the upper right limb segments (42 vs 63; left-to-right ratio, 3:2). The forearm was the segment most affected by stenotic PAD (62 segments, 3.37%). The arm was the segment most affected by occlusive PAD (14 segments, 0.76%). Diabetes mellitus (DM) and hypertension (HTN) were significant predictors of PAD (p = 0.046). In patients with DM, the occlusive form of PAD was dominant in the arm (18.18%); however, the stenotic form prevailed in the forearm (72.72%). In patients with HTN, the occlusive form of PAD was predominant in the arm (45.45%); however, the stenotic form tended to occur in the arm and forearm (90.90%).

Conclusion

The distribution patterns of upper extremity PAD are linked to its underlying pathophysiology. HTN and DM are the most frequent comorbidities in patients with upper extremity PAD. Angiographically, PAD in these patients is likely to present as stenosis rather than as occlusion. This is vital for interventionists who deviate from radial arterial access in patients with PAD. Therefore, targeted screening standards are required, and further studies on PAD are warranted.

Autologous angiogenic therapy with cultured mesenchymal stromal cells in platelet-rich plasma for critical limb ischemia

Introduction

The prevalence of diabetes mellitus is increasing globally, including in Japan. Patients with diabetes often experience microangiopathy and macroangiopathy, which lead to difficult-to-treat foot ulcers and diabetic gangrene. Conventional cellular therapies have limited safety and are invasive. In this study, we investigated the use of cultured autologous mesenchymal stromal cells derived from the bone marrow and grown in platelet-rich plasma as a potential treatment for diabetic complications.

Methods

A prospective clinical trial was conducted to assess safety as the primary endpoint and efficacy as the secondary endpoint of the aforementioned therapy in five patients with critical limb ischemia, with or without hemodialysis.

Results

Five patients with critical limb ischemia were enrolled between 2016 and 2019, three of whom underwent hemodialysis. Platelet-rich plasma was obtained from 288 ± 39.6 mL of blood/patient, yielding 31.6 ± 1.67 mL of platelet-rich plasma. Bone marrow aspiration yielded 18.4 ± 4.77 mL/patient, and 4.64 ± 1.51 × 107 cells were incubated for 16 ± 2.8 days to obtain 3.26 ± 0.33 × 107 mesenchymal stromal cells. Although several adverse events were observed, none were directly attributed to cell therapy. Clinical severity, as assessed by both the Fontaine stage and Rutherford category, improved significantly following therapy. This improvement was accompanied by enhancements in the 6-min walking distance, dorsal skin perfusion pressure, ankle transcutaneous partial oxygen pressure, and ankle brachial pressure index.

Conclusion

Autologous angiogenic therapy with cultured mesenchymal stromal cells derived from the bone marrow and grown in platelet-rich plasma is a safe and feasible, and was expected as a potential treatment for critical limb ischemia.

Global disease burden and its attributable risk factors of peripheral arterial disease

Peripheral arterial disease (PAD) is a prevalent subtype of atherosclerotic cardiovascular diseases. It is crucial to assess the PAD-related burden and its attributable risk factors. We use the Global Burden of Disease study 2019 database to calculate the incidence, prevalence, mortality, disability-adjusted life years (DALY), attributable risk factors and estimated annual percentage change. The disease burden of PAD grows significantly with age accompanied by prominent heterogeneity between male and female. Despite the increase in the absolute numbers of disease burden from 1990 to 2019, the global PAD-related age-standardized death rate (ASDR) and age-standardized disability-adjusted life years rate (ASDALYR) have a mild downward trend from 1990 to 2019, which negatively correlated with sociodemographic index (SDI). Smoking and high systolic blood pressure (SBP) were the primary attributable risk factors for males (ASDR: 33.4%; ASDALYR: 43.4%) and females (ASDR: 25.3%; ASDALYR: 27.6%), respectively. High fasting plasma glucose (FPG) had become the second risk factor for ASDR (males: 28.5%; females: 25.2%) and ASDALYR (males: 29.3%; females: 26.3%) with an upward tendency. Low-middle SDI regions were predicted to have the most remarkable upward trend of PAD-related burden caused by high FPG. Smoking caused more disease burden in males before 85-90 years old and females before 65-70 years old, while high FPG and high SBP caused more burden after that. The patterns of PAD-related burden and its attributable risk factors are heterogeneous across ages, genders, and SDI regions. To reduce disease burden, tailored strategies should be implemented.

The CathPilot: Performance Validation and Preclinical Safety and Feasibility Assessment

OBJECTIVES

Peripheral endovascular revascularization procedures often fail due to technical limitations of guidewire support, steering, and visualization. The novel CathPilot catheter aims to address these challenges. This study assesses the safety and feasibility of the CathPilot and compares its performance to conventional catheters for peripheral vascular interventions.

METHODS

The study compared the CathPilot to non-steerable and steerable catheters. The success rates and access times for a relevant target inside a tortuous vessel phantom model were assessed. The reachable workspace within the vessel and the guidewire's force delivery capabilities were also evaluated. To validate the technology, chronic total occlusion tissue samples were used ex vivo to compare crossing success rates with conventional catheters. Finally, in vivo experiments in a porcine aorta were conducted to evaluate safety and feasibility.

RESULTS

The success rates for reaching the set targets were 31%, 69%, and 100% with the non-steerable catheter, the steerable catheter, and the CathPilot, respectively. CathPilot had a significantly larger reachable workspace, and allowed for up to four times higher force delivery and pushability. In crossing of chronic total occlusion samples, the CathPilot achieved a success rate of 83% and 100%, for fresh and fixed lesions respectively, which was also significantly higher than conventional catheters. The device was fully functional in the in vivo study, and there were no signs of coagulation or damage to the vessel wall.

CONCLUSION

This study shows the safety and feasibility of the CathPilot system and its potential to reduce failure and complication rates in peripheral vascular interventions. The novel catheter outperformed conventional catheters in all defined metrics. This technology can potentially improve the success rate and outcome of peripheral endovascular revascularization procedures.

Preoperative Depression is Associated with Worse Outcomes after The Lower Extremity Revascularization

OBJECTIVE

This retrospective study sought to describe the association between preoperative diagnosis of depression and major adverse events after infrainguinal bypass surgery or peripheral vascular intervention (PVI).

METHODS

We retrospectively analyzed a consecutive series of all patients undergoing PVI and/or infrainguinal bypass surgery at a single tertiary institution between 2010 and 2019. Propensity matching and Cox regression analysis were conducted to examine the impact of comorbid depression on the incidence of major adverse events (MAEs), defined as re-intervention, major amputation, or death, within 2 years of surgery.

RESULTS

Of all patients (n = 512) undergoing intervention at our institution, 166 (32.4%) suffered an MAE and 169 (33.0%) patients had a preoperative diagnosis of depression. After propensity score matching, univariate (HR, 1.7; 95% CI, 1.1-2.7) and multivariable hazard analyses (aHR, 1.50; [1.1-2.2]) demonstrate that there is a statistically significant relationship between the diagnosis of depression and increased MAE.

CONCLUSION

Over one-third of our lower extremity revascularization patients were noted to have a preoperative diagnosis of depression. After intervention, these patients had worse outcomes compared to patients without depression; this finding was more evident in patients who underwent PVI mainly due to high overall mortality rate. Prospective studies are necessary to better understand this association and to ascertain if early intervention can improve post-procedure vascular outcomes.

Global burden of peripheral artery disease and its risk factors, 1990-2019: a systematic analysis for the Global Burden of Disease Study 2019

BACKGROUND

Peripheral artery disease is a growing public health problem. We aimed to estimate the global disease burden of peripheral artery disease, its risk factors, and temporospatial trends to inform policy and public measures.

METHODS

Data on peripheral artery disease were modelled using the Global Burden of Disease, Injuries, and Risk Factors Study (GBD) 2019 database. Prevalence, disability-adjusted life years (DALYs), and mortality estimates of peripheral artery disease were extracted from GBD 2019. Total DALYs and age-standardised DALY rate of peripheral artery disease attributed to modifiable risk factors were also assessed.

FINDINGS

In 2019, the number of people aged 40 years and older with peripheral artery disease was 113 million (95% uncertainty interval [UI] 99·2-128·4), with a global prevalence of 1·52% (95% UI 1·33-1·72), of which 42·6% was in countries with low to middle Socio-demographic Index (SDI). The global prevalence of peripheral artery disease was higher in older people, (14·91% [12·41-17·87] in those aged 80-84 years), and was generally higher in females than in males. Globally, the total number of DALYs attributable to modifiable risk factors in 2019 accounted for 69·4% (64·2-74·3) of total peripheral artery disease DALYs. The prevalence of peripheral artery disease was highest in countries with high SDI and lowest in countries with low SDI, whereas DALY and mortality rates showed U-shaped curves, with the highest burden in the high and low SDI quintiles.

INTERPRETATION

The total number of people with peripheral artery disease has increased globally from 1990 to 2019. Despite the lower prevalence of peripheral artery disease in males and low-income countries, these groups showed similar DALY rates to females and higher-income countries, highlighting disproportionate burden in these groups. Modifiable risk factors were responsible for around 70% of the global peripheral artery disease burden. Public measures could mitigate the burden of peripheral artery disease by modifying risk factors.

FUNDING

Bill & Melinda Gates Foundation.

Vascular regeneration and skeletal muscle repair induced by long-term exposure to SDF-1α derived from engineered mesenchymal stem cells after hindlimb ischemia

Despite recent progress in medical and endovascular therapy, the prognosis for patients with critical limb ischemia (CLI) remains poor. In response, various stem cells and growth factors have been assessed for use in therapeutic neovascularization and limb salvage in CLI patients. However, the clinical outcomes of cell-based therapeutic angiogenesis have not provided the promised benefits, reinforcing the need for novel cell-based therapeutic angiogenic strategies to cure untreatable CLI. In the present study, we investigated genetically engineered mesenchymal stem cells (MSCs) derived from human bone marrow that continuously secrete stromal-derived factor-1α (SDF1α-eMSCs) and demonstrated that intramuscular injection of SDF1α-eMSCs can provide long-term paracrine effects in limb ischemia and effectively contribute to vascular regeneration as well as skeletal muscle repair through increased phosphorylation of ERK and Akt within the SDF1α/CXCR4 axis. These results provide compelling evidence that genetically engineered MSCs with SDF-1α can be an effective strategy for successful limb salvage in limb ischemia.

High-intensity interval training in patients with intermittent claudication

OBJECTIVE

Provision, uptake, adherence, and completion rates for supervised exercise programs (SEP) for intermittent claudication (IC) are low. A shorter, more time-efficient, 6-week, high-intensity interval training (HIIT) program may be an effective alternative that is more acceptable to patients and easier to deliver. The aim of this study was to determine the feasibility of HIIT for patients with IC.

METHODS

A single arm proof-of-concept study, performed in secondary care, recruiting patients with IC referred to usual-care SEPs. Supervised HIIT was performed three times per week for 6 weeks. The primary outcome was feasibility and tolerability. Potential efficacy and potential safety were considered, and an integrated qualitative study was undertaken to consider acceptability.

RESULTS

A total of 280 patients were screened: 165 (59%) were eligible, and 40 (25%) were recruited. The majority (n = 31; 78%) of participants completed the HIIT program. The remaining nine patients were withdrawn or chose to withdraw. Completers attended 99% of training sessions, completed 85% of sessions in full, and performed 84% of completed intervals at the required intensity. There were no related serious adverse events. Maximum walking distance (+94 m; 95% confidence interval, 66.6-120.8 m) and the SF-36 physical component summary (+2.2; 95% confidence interval, 0.3-4.1) were improved following completion of the program.

CONCLUSIONS

Uptake to HIIT was comparable to SEPs in patients with IC, but completion rates were higher. HIIT appears feasible, tolerable, and potentially safe and beneficial for patients with IC. It may provide a more readily deliverable, acceptable form of SEP. Research comparing HIIT with usual-care SEPs appears warranted.

Prospective Assessment of the Diagnostic Accuracy of Multi-site Photoplethysmography Pulse Measurements for Diagnosis of Peripheral Artery Disease in Primary Care

Peripheral arterial disease (PAD) is associated with cerebral and coronary artery disease. Symptomatic PAD affects about 5% of people over 55 years; many more have asymptomatic PAD. Early detection enables modification of arterial disease risk factors. Diagnostically, assessment of symptoms or signs can be unreliable; ankle brachial pressure index (ABPI) testing is time-consuming and few healthcare professionals are properly trained. This study assessed the diagnostic accuracy of multi-site photoplethysmography (MPPG), an alternative non-invasive test for PAD, in primary care. PAD patients identified from general practice registers were age- and sex-matched with controls. Participants were assessed using MPPG, ABPI and duplex ultrasound (DUS). Outcome measures were sensitivity and specificity of MPPG and ABPI (relative to DUS) and concordance. MPPG test results were available in 249 of 298 eligible participants from 16 practices between May 2015 and November 2016. DUS detected PAD in 101/249 (40.6%). MPPG sensitivity was 79.8% (95% confidence interval [CI] 69.9-87.6%), with specificity 71.9% (95% CI 63.7-79.2%). ABPI sensitivity was 80.2% (95% CI 70.8-87.6%), with specificity 88.6% (95% CI 82-93.5%). With comparable sensitivity to ABPI, MPPG is quick, automated and simpler to do than ABPI; it offers the potential for rapid and accessible PAD assessments in primary care.

Caught Between Heart and Limbs: Navigating the Treatment of Patients With CAD and PAD in an Overwhelmed Healthcare System

Peripheral arterial disease (PAD) and coronary artery disease (CAD) are manifestations of atherosclerosis, affecting a substantial proportion of the population. Despite their interrelation, the prevalence of CAD in severe PAD varies, prompting the need to understand their complex relationship. This study retrospectively analyzes prospectively collected data from a high-volume vascular center to assess CAD prevalence, risk factors, and implications for patients undergoing vascular surgery. Among 667 arterial disease patients, 19.5% underwent coronary angiography, with CAD detected in 61.5% of cases. CAD varied across vascular beds. Decision-making around preoperative coronary angiography and revascularization remains complex, with benefits for high-risk patients still being debated. In accordance with current guidelines, the routine practice of coronary revascularization preceding vascular surgery is generally discouraged. This study underscores the need for risk stratification to identify patients who might benefit from coronary revascularization prior to vascular surgery while adhering to cost-effectiveness and avoiding unnecessary and time-consuming diagnostics in the majority of patients. Patient demographics, risk factors, and clinical presentation were analyzed alongside hospital stay, mortality, and complications. The study highlights the challenges in managing patients with concurrent CAD and PAD and calls for improved protocols for treating this high-risk group.

Anesthetic management for lower extremity vascular bypass procedures: The impact of general or regional anesthesia on clinical outcomes

PURPOSE

Postoperative complications after major surgery, especially vascular procedures, are associated with a significant increase in costs and mortality. Previous studies evaluating general anesthesia versus regional or neuraxial anesthesia for infrainguinal bypass have produced conflicting results. The main aim of the present study is to review current evidence on the application of regional or general anesthesia in patients undergoing infrainguinal bypass surgery and its potential favorable effects on postoperative outcomes.

CONTENTS

Patients undergoing vascular surgery often have multiple comorbidities, and it is important to outline both benefits and risks of regional anesthesia techniques. Neuraxial anesthesia in vascular surgery allows overall avoidance of general anesthesia and does provide short-term benefits beyond analgesia. Previous observational studies suggest that neuraxial anesthesia for lower limb revascularization may reduce morbidity and length of stay. However, evidence of long-term benefits is lacking in most procedures and further work is still warranted.

CONCLUSIONS

Neuraxial anesthesia is usually an effective anesthesia technique for infrainguinal bypass surgery. Elderly patients and those with underlying respiratory problems may display some benefit from neuraxial anesthesia. Further evaluation within institutions should be performed to identify which patients would most benefit from regional techniques. Notably, systemic antithrombotic and anticoagulation therapy is common among this population and may affect anesthetic choices.

Tourniquet use for people with peripheral arterial disease undergoing major lower limb amputations

BACKGROUND

At least 7000 major lower limb amputations (MLLAs) are performed in the UK each year, 80% of which are due to peripheral arterial disease (PAD). Intraoperative blood loss can have a deleterious effect on patient outcomes, and its replacement with transfused blood is not without risk. Tourniquets can be used in lower limb surgical procedures to provide a bloodless surgical field, minimise intraoperative blood loss, and reduce perioperative blood transfusion requirements. Although their safety has been demonstrated in certain orthopaedic operations, their use among people with PAD undergoing MLLA remains controversial. Many clinicians are concerned about tourniquets potentially compromising perfusion of the stump and thereby impacting wound healing through direct tissue injury, damage to the arterial supply of the wound, or both.

OBJECTIVES

To assess the safety and effectiveness of tourniquet use in people undergoing MLLA for complications of PAD, specifically with regard to intraoperative blood loss, change in haemoglobin levels, transfusion rates, wound healing, need for revision surgery, and postoperative complications including mortality.

SEARCH METHODS

We searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase, and CINAHL databases and World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials registers from inception to 17 May 2022.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing tourniquet use to no tourniquet use among people with PAD undergoing MLLA.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Primary outcomes were intraoperative blood loss, fall in haemoglobin levels, and perioperative blood transfusion requirement. Secondary outcomes were primary wound-healing rates, stump revision rates, other postoperative complications defined as per Clavien-Dindo classification, and postoperative mortality at 30 days and at maximal follow-up. We used GRADE to assess the certainty of evidence for each outcome.

MAIN RESULTS

One RCT met our inclusion criteria, which was a prospective randomised blinded controlled trial conducted in Sheffield, UK in 2006. In total 64 participants undergoing transtibial amputation for non-reconstructable PAD were randomised to either tourniquet or no tourniquet to assess for intraoperative blood loss, fall in haemoglobin, transfusion requirement, wound healing, stump breakdown and revision. Ten participants were excluded postrandomisation (five from the tourniquet group and five from the no tourniquet group). The reported median volume of intraoperative blood loss was significantly less in the tourniquet group (255 mL (interquartile range (IQR) 150 to 572.5 mL))) compared to the control group (550 mL (IQR 255 to 1050 mL)) (P = 0.014). There was a significantly lower median drop in haemoglobin concentration in the tourniquet group (1.0 g/dL (IQR 0.6 to 2.4 g/dL)) compared to the control group (1.8 g/dL (IRQ 0 to 1.2 g/dL)) (P = 0.035). There was a significantly lower perioperative blood transfusion requirement in the tourniquet group (8 participants, 32%) compared to the control group (14 participants, 48%) (P = 0.047). There were no clear differences in wound breakdown, stump revision, primary wound healing at six weeks, postoperative complications (myocardial infarction, cardiac arrhythmias, pulmonary oedema), and death between groups. We assessed the one included study as at low risk of bias for sequence generation and blinding of outcome assessors; high risk of bias for incomplete outcome data and selective outcome reporting; and unclear risk of bias for allocation concealment, blinding of participants and personnel, and other sources of bias. We assessed the certainty of the evidence as low or very low due to risk of bias, small sample size, and the study being insufficiently powered for most outcomes.

AUTHORS' CONCLUSIONS

This review identified only one small historical RCT evaluating tourniquet use in MLLA. Tourniquets appeared to reduce intraoperative blood loss, drop in haemoglobin, and blood transfusion requirements following transtibial amputations for people with PAD. However, it is unclear whether tourniquets affect wound healing, stump revision rates, postoperative complications, or mortality. High-certainty evidence is required to inform clinical decision-making for the use of tourniquets in these patients.

Lower Extremity Peripheral Arterial Disease and Its Relationship with Adverse Outcomes in Kidney Transplant Recipients: A Retrospective Cohort Study

The purpose of the study was to characterize lower extremity peripheral arterial disease (LEPAD) in a series of kidney transplant patients and to assess the impact on adverse outcomes. A retrospective cohort study was conducted including kidney transplant recipient patients who underwent screening for LEPAD. The outcomes evaluated were classified as perioperative and post-transplant, including cardiovascular events, amputation, mortality, and loss of the graft. A total of 141 renal transplant patients screened for LEPAD were identified, with an average follow-up of 3 years. LEPAD occurred in 14.2% (20/141). No differences in cardiovascular risk factors were found between the groups, except for smoking (45% vs. 24%, p < 0.05). In the group with LEPAD, the most compromised anatomical segment was the infrapopliteus, with no iliac involvement found. The Cox proportional hazards model indicated that the variables age, gender, and weight were significant in patients with LEPAD. There were no differences between the groups in terms of graft loss and death. The infrapopliteal segment is the area of greatest stenosis in kidney transplant patients with LEPAD. Together with smoking, they can explain the presence of major amputations in kidney transplant patients; however, they had no impact on graft functionality or death.

Mast cell activation and degranulation in acute artery injury: A target for post-operative therapy

The increasing incidence of cardiovascular disease (CVD) has led to a significant ongoing need to address this surgically through coronary artery bypass grafting (CABG) and percutaneous coronary interventions (PCI). From this, there continues to be a substantial burden of mortality and morbidity due to complications arising from endothelial damage, resulting in restenosis. Whilst mast cells (MC) have been shown to have a causative role in atherosclerosis and other vascular diseases, including restenosis due to vein engraftment; here, we demonstrate their rapid response to arterial wire injury, recapitulating the endothelial damage seen in PCI procedures. Using wild-type mice, we demonstrate accumulation of MC in the femoral artery post-acute wire injury, with rapid activation and degranulation, resulting in neointimal hyperplasia, which was not observed in MC-deficient KitW-sh/W-sh mice. Furthermore, neutrophils, macrophages, and T cells were abundant in the wild-type mice area of injury but reduced in the KitW-sh/W-sh mice. Following bone-marrow-derived MC (BMMC) transplantation into KitW-sh/W-sh mice, not only was the neointimal hyperplasia induced, but the neutrophil, macrophage, and T-cell populations were also present in these transplanted mice. To demonstrate the utility of MC as a target for therapy, we administered the MC stabilizing drug, disodium cromoglycate (DSCG) immediately following arterial injury and were able to show a reduction in neointimal hyperplasia in wild-type mice. These studies suggest a critical role for MC in inducing the conditions and coordinating the detrimental inflammatory response seen post-endothelial injury in arteries undergoing revascularization procedures, and by targeting the rapid MC degranulation immediately post-surgery with DSCG, this restenosis may become a preventable clinical complication.

Peripheral Ischemia Imprints Epigenetic Changes in Hematopoietic Stem Cells to Propagate Inflammation and Atherosclerosis

BACKGROUND

Peripheral ischemia caused by peripheral artery disease is associated with systemic inflammation, which may aggravate underlying comorbidities such as atherosclerosis and heart failure. However, the mechanisms of increased inflammation and inflammatory cell production in patients with peripheral artery disease remain poorly understood.

METHODS

We used peripheral blood collected from patients with peripheral artery disease and performed hind limb ischemia (HI) in Apoe-/- mice fed a Western diet and C57BL/6J mice with a standard laboratory diet. Bulk and single-cell RNA sequencing analysis, whole-mount microscopy, and flow cytometry were performed to analyze hematopoietic stem and progenitor cell (HSPC) proliferation, differentiation, and relocation.

RESULTS

We observed augmented numbers of leukocytes in the blood of patients with peripheral artery disease and Apoe-/- mice with HI. RNA sequencing and whole-mount imaging of the bone marrow revealed HSPC migration into the vascular niche from the osteoblastic niche and their exaggerated proliferation and differentiation. Single-cell RNA sequencing demonstrated alterations in the genes responsible for inflammation, myeloid cell mobilization, and HSPC differentiation after HI. Heightened inflammation in Apoe-/- mice after HI aggravated atherosclerosis. Surprisingly, bone marrow HSPCs expressed higher amounts of the receptors for IL (interleukin)-1 and IL-3 after HI. Concomitantly, the promoters of Il1r1 and Il3rb had augmented H3K4me3 and H3K27ac marks after HI. Genetic and pharmacological inhibition of these receptors resulted in suppressed HSPC proliferation, reduced leukocyte production, and ameliorated atherosclerosis.

CONCLUSIONS

Our findings demonstrate increased inflammation, HSPC abundance in the vascular niches of the bone marrow, and elevated IL-3Rb and IL-1R1 (IL-1 receptor 1) expression in HSPC following HI. Furthermore, the IL-3Rb and IL-1R1 signaling plays a pivotal role in HSPC proliferation, leukocyte abundance, and atherosclerosis aggravation after HI.

Demographic and regional trends of peripheral artery disease-related mortality in the United States, 2000 to 2019

INTRODUCTION

Peripheral artery disease (PAD) is a common progressive atherosclerotic disease associated with significant morbidity and mortality in the US; however, data regarding PAD-related mortality trends are limited. This study aims to characterize contemporary trends in mortality across sociodemographic and regional groups.

METHODS

The Centers for Disease Control and Prevention Wide-Ranging OnLine Data for Epidemiologic Research (CDC WONDER) was queried for data regarding PAD-related deaths from 2000 to 2019 in the overall sample and different demographic (age, sex, race/ethnicity) and regional (state, urban-rural) subgroups. Crude and age-adjusted mortality rates (CMR and AAMR, respectively) per 100,000 people were calculated. Associated annual percentage changes (APC) were computed using Joinpoint Regression Program Version 4.9.0.0 trend analysis software.

RESULTS

Between 2000 and 2019, a total of 1,959,050 PAD-related deaths occurred in the study population. Overall, AAMR decreased from 72.8 per 100,000 in 2000 to 32.35 per 100,000 in 2019 with initially decreasing APCs followed by no significant decline from 2016 to 2019. Most demographic and regional subgroups showed initial declines in AAMRs during the study period, with many groups exhibiting no change in mortality in recent years. However, men, non-Hispanic (NH) Black or African American individuals, people aged ⩾ 85 years, and rural counties were associated with the highest AAMRs of their respective subgroups. Notably, there was an increase in crude mortality rate among individuals 25-39 years of age from 2009 to 2019.

CONCLUSION

Despite initial improvement, PAD-related mortality has remained stagnant in recent years. Disparities have persisted across several demographic and regional groups, requiring further investigation.

Correlation between Coronary Artery Disease with Other Arterial Systems: Similar, Albeit Separate, Underlying Pathophysiologic Mechanisms

Atherosclerosis is a multifactorial systemic disease that affects the entire arterial tree, although some areas are more prone to lipid deposits than others. Moreover, the histopathological composition of the plaques differs, and the clinical manifestations are also different, depending on the location and structure of the atherosclerotic plaque. Some arterial systems are correlated with each other more than in that they simply share a common atherosclerotic risk. The aim of this perspective review is to discuss this heterogeneity of atherosclerotic impairment in different arterial districts and to investigate the current evidence that resulted from studies of the topographical interrelations of atherosclerosis.

Peripheral artery disease and extracorporeal membrane oxygenation: Examining a high-risk cohort over time

OBJECTIVE

Venoarterial extracorporeal membrane oxygenation (VA-ECMO) is a resource-intensive approach for the management of refractory cardiogenic shock. Within this population exists a substantial cohort of patients with peripheral artery disease (PAD), which independently increases the risk of complications and all-cause mortality. We studied 10-year national trends of the impact of PAD among VA-ECMO recipients to better understand the prevalence of PAD and implications on outcomes in this vulnerable population.

METHODS

This 10-year retrospective, propensity score-matched study identified all adult patients (≥18) who underwent VA-ECMO between 2009 and 2018, from a large US database (National Inpatient Sample). Patients with an ICD diagnosis of PAD were identified. The primary endpoints of in-hospital mortality, bleeding complications and major limb loss (above- or below-knee amputation) were compared between patients with PAD to those without.

RESULTS

A total of 6768 patients were identified, of which 342 (5.3%) had PAD. The median age at admission was significantly higher in PAD patients [64 years vs. 55 years; p < .01], as was male gender [71% vs. 64%; p < .01]. Patients with PAD had higher rates of smoking (38.9% vs. 23.3%), hypertension (71.1% vs. 50%), diabetes (37.4% vs. 27.0%), chronic kidney disease (30.1% vs. 18.0%), coronary artery disease (76.0% vs. 35.0%) and dyslipidemia (76.0% vs. 35.0); all p < .01. After propensity-matching 2:1 for comorbidities, PAD patients were found to have significantly greater overall complications, including in-hospital mortality, bleeding, surgical wound infections, pseudoaneurysms, and major adverse limb events [71.9% vs. 63.9%; p < .01]. Subgroup analysis revealed greater in-hospital mortality [62.2% vs. 55.3%; p < .05], major amputations [4.1% vs. 0.3%; p < .01] and blood transfusions [32.2% vs. 26.2%; p < .05] in PAD patients. Over 2014-2018, the non-PAD group demonstrated statistically discernable trends in a 51.1% decrease in overall complications and a 28.1% increase in survival to discharge (all p < .01). Over the same time period the PAD cohort experienced a modest, nonsignificant, decrease in complications [7.0%, p = .40] and a decrease in those surviving to discharge [47.1% vs. 40.5%, p = .91].

CONCLUSION

Patients with PAD on VA-ECMO are sicker at baseline and experience significantly greater major amputations and higher in-hospital mortality. They have not benefitted from the considerable decrease in complication rates and increase in survival to discharge over time as compared to their non-PAD counterparts. These findings demonstrate the substantial frailty of the PAD population within an already high-risk cohort, and highlight the need for better procedural approaches and innovative technologies.

Joint effect of highly-sensitive cardiac troponin T and ankle-brachial index on incident cardiovascular events: The MESA and CHS

Background

Elevated highly-sensitive cardiac troponin-T (hs-cTnT≥14 ng/L) and low ankle-brachial index (ABI<0.9) are risk factors for atherosclerotic cardiovascular diseases (ASCVD) but their joint effect on the risk of ASCVD events is unknown.

Methods

We used data from the two population-based cohort studies, the Multi-Ethnic study of Atherosclerosis (MESA) and Cardiovascular Heart Study (CHS) among 10,897 participants free of CVD events at baseline (mean age 66.3 years, 44.7% males). Incident ASCVD was defined as CHD (fatal/non-fatal MI or revascularization), transient ischemic attack, or stroke,. Hazard ratio (HR) and 95% CI was calculated from a Cox regression model. Interaction on the additive scale was assessed using relative excess risk due to interaction (RERI) and interaction on the multiplicative scale was assessed by Likelihood ratio (LR) test.

Results

At baseline (2000-2002 for MESA and 1989-1990 for CHS), 10.2% of participants had elevated hs-cTnT and 7.5% had low ABI. During a median follow-up of 13.6 years (interquartile range, 7.5-14.7 years), there were 2590 incident ASCVD and 1542 incident CHD events. The hazard of CHD and ASCVD was higher in participants with both elevated hs-cTnT and low ABI [HR(95% CI): CHD: 2.04 (1.45, 2.88), ASCVD: 2.05 (1.58, 2.66)] than those with only elevated hs-cTnT [CHD: 1.65 (1.37, 1.99), ASCVD: 1.67 (1.44, 1.99)] or only low ABI [CHD: 1.87 (1.52, 2.31), ASCVD: 1.67 (1.42, 1.97)]. Antagonistic multiplicative interaction was observed for CHD (LR test p-value=0.042) but not for ASCVD (LR test p-value =0.08). No significant additive interaction was detected for CHD and ASCVD (RERI p-value ≥0.23).

Conclusion

The observed joint effect of elevated cTnT and low ABI on ASCVD risk was smaller (i.e., antagonistic interaction) than that expected by the combined independent effects of each risk factor.

A Severe Necrotizing Inflammatory Reaction of Leg Wounds Following Autologous Peripheral Blood Total Nucleated Cells Treatment in an Old Patient With Rheumatoid Arthritis and No-Option Chronic Limb-Threatening Ischemia: Is Cell Therapy Suitable for All Patients?

Chronic limb-threatening ischemia (CLTI) represents an unfavorable evolution of peripheral artery disease, characterized by pain at rest, ulceration, and gangrene and also by an increased risk of cardiovascular events, amputations, and death. According to scientific literature, in almost one third of cases affected by CLTI, defined as no-option CLTI patients, revascularization strategies are not feasible. In the past decade, several studies investigated the role of therapeutic angiogenesis through cell autologous therapy, administered through intramuscular injections or multiple local intralesional and perilesional injections. In this article, we report the case of a necrotizing inflammatory reaction in a patient affected by CLTI and chronic leg wounds that occurred on the multiple injection sites after autologous peripheral blood-derived mononuclear cells (PB-TNCs) transplantation. Since the patient was affected by corticosteroid-induced skin atrophy and rheumatoid arthritis, we hypothesize that an increased skin fragility and a mechanism of immune-mediated pathergy could have been main factors leading to worsening of wounds. This case report strongly suggests the urgent need to better define the indications and contraindications of cell therapy, and further studies of adequate methodology are required to definitively assess the efficacy and safety of autologous cell therapy by local injections of PB-TNCs in patients with chronic inflammatory disorder, such as rheumatoid arthritis, especially in case of concomitant marked skin atrophy. Pending definitive evidence from literature, a strong caution is needed in patients affected by chronic systemic inflammatory diseases, since multiple injections, acting as mechanical stimulus and pathergy trigger, might exacerbate a severe and uncontrolled inflammatory response.

Experimental Protocol and Phantom Design and Development for Performance Characterization of Conventional Devices for Peripheral Vascular Interventions

Conventional catheter-based interventions for treating peripheral artery disease suffer high failure and complication rates. The mechanical interactions with the anatomy constrain catheter controllability, while their length and flexibility limit their pushability. Also, the 2D X-ray fluoroscopy guiding these procedures fails to provide sufficient feedback about the device location relative to the anatomy. Our study aims to quantify the performance of conventional non-steerable (NS) and steerable (S) catheters in phantom and ex vivo experiments. In a 10 mm diameter, 30 cm long artery phantom model, with four operators, we evaluated the success rate and crossing time in accessing 1.25 mm target channels, the accessible workspace, and the force delivered through each catheter. For clinical relevance, we evaluated the success rate and crossing time in crossing ex vivo chronic total occlusions. For the S and NS catheters, respectively, users successfully accessed 69 and 31% of the targets, 68 and 45% of the cross-sectional area, and could deliver 14.2 and 10.2 g of mean force. Using a NS catheter, users crossed 0.0 and 9.5% of the fixed and fresh lesions, respectively. Overall, we quantified the limitations of conventional catheters (navigation, reachable workspace, and pushability) for peripheral interventions; this can serve as a basis for comparison with other devices.

Specialty Balloons for Vessel Preparation During Infrainguinal Endovascular Revascularization Procedures: A Review of Literature

Balloon angioplasty with/without utilizing drug eluting technology or stenting constitutes the treatment of choice for a significant percentage of patients with peripheral artery disease requiring an intervention. However, in cases of diffuse disease and plaque complexity, angioplasty may lead to dissection, recoil, and/or early restenosis, making vessel preparation a key component for successful and durable endovascular revascularization outcome. This review of literature aims to present contemporary data for several commercially available specialty balloons that have been designed to minimize the arterial wall stress of conventional balloon angioplasty and facilitate technical success, as well as long-term patency.

Applications of artificial intelligence for patients with peripheral artery disease

OBJECTIVE

Applications of artificial intelligence (AI) have been reported in several cardiovascular diseases but its interest in patients with peripheral artery disease (PAD) has been so far less reported. The aim of this review was to summarize current knowledge on applications of AI in patients with PAD, to discuss current limits, and highlight perspectives in the field.

METHODS

We performed a narrative review based on studies reporting applications of AI in patients with PAD. The MEDLINE database was independently searched by two authors using a combination of keywords to identify studies published between January 1995 and December 2021. Three main fields of AI were investigated including natural language processing (NLP), computer vision and machine learning (ML).

RESULTS

NLP and ML brought new tools to improve the screening, the diagnosis and classification of the severity of PAD. ML was also used to develop predictive models to better assess the prognosis of patients and develop real-time prediction models to support clinical decision-making. Studies related to computer vision mainly aimed at creating automatic detection and characterization of arterial lesions based on Doppler ultrasound examination or computed tomography angiography. Such tools could help to improve screening programs, enhance diagnosis, facilitate presurgical planning, and improve clinical workflow.

CONCLUSIONS

AI offers various applications to support and likely improve the management of patients with PAD. Further research efforts are needed to validate such applications and investigate their accuracy and safety in large multinational cohorts before their implementation in daily clinical practice.

Relationship between Arachidonate 5-Lipoxygenase-Activating Protein Gene and Peripheral Arterial Disease in Elderly Patients Undergoing General Surgery: A Retrospective Observational Study

Patients with peripheral arterial disease (PAD) are at a higher risk of developing postoperative complications. Arachidonate 5-lipoxygenase-activating protein (ALOX5AP) plays an important role in atherosclerosis pathogenesis. In this study, the relationship between PAD and several single nucleotide polymorphisms (SNPs) of ALOX5AP (rs17216473, rs10507391, rs4769874, rs9551963, rs17222814, and rs7222842) was investigated in elderly patients undergoing general surgery. The medical records of 129 patients aged > 55 years who underwent elective general surgery between May 2018 and August 2019 were retrospectively reviewed. The A/A in rs17216473, A/A in rs10507391, G/G in rs4769874, and A/A in rs9551963 were calculated as 0 points and the rest as 1 point to define the genetic risk score. The prevalence of PAD tended to increase with higher genetic risk scores (patients had less ALOX5AP gene polymorphism of A/A in rs17216473, A/A in rs10507391, G/G in rs4769874, or A/A in rs9551963) (p = 0.005). Multivariate logistic regression analysis revealed that the genetic risk score (p = 0.009) and age (p = 0.007) were positively correlated with the prevalence of PAD. Genetic polymorphisms of ALOX5AP and age were associated with the prevalence of PAD in this study.

The association of depression with mortality and major adverse limb event outcomes in patients with peripheral artery disease: A systematic review and meta-analysis

BACKGROUND

Peripheral artery disease (PAD) is highly prevalent and associated with poor outcomes. Depression is a risk factor for adverse outcomes in patients with coronary artery disease. Despite evidence showing that depression is common in patients with PAD, less is known about its association with adverse prognostic outcomes. To address this, we conducted a systematic review and meta-analysis to summarize the association between depression and outcomes in patients with PAD.

METHODS

We performed a systematic search of eight databases to January 2022 including studies that reported a risk estimate for the association of depression or depressive symptoms with all-cause mortality or major adverse limb events (MALE) in patients with PAD and pooled results in a meta-analysis. Risk of bias was assessed using ROBINS-I.

RESULTS

Of the 7048 articles screened, 5 observational studies with 119,123 patients were included. A total of 16.2 % had depression or depressive symptoms. Depression was associated with a statistically significant increased risk of all-cause mortality (HR 1.24, confidence interval 1.07-1.25, p = .005). The association between depression and MALE was not significant but trended toward a positive association.

LIMITATIONS

Due to lack of data, results were limited by a single study with a large sample size, overrepresentation of men, and lack of information of depression severity or treatment status.

CONCLUSION

Depression or depressive symptoms are associated with a 24 % increased risk of all-cause mortality in patients with PAD. Future work should explore the mechanisms and directionality of this association and identify depression as an important comorbidity to address for patients with PAD.

REGISTRATION

PROSPERO CRD 42021223694.

Temporal Trends in Patients with Peripheral Artery Disease Influenced by COVID-19 Pandemic

Background: The COVID-19 pandemic influences the health care management of acute and chronic diseases. Data concerning the influence of the pandemic on hospitalizations of patients with peripheral artery disease (PAD) are sparse. Methods: We analysed all patients hospitalized due to PAD between 1 January 2019 and 31 December 2020 in Germany. Hospitalizations of PAD patients during the pre-pandemic year 2019 were compared to the pandemic year 2020. Results: Overall, 361,029 hospitalizations of PAD patients in the years 2019 and 2020 (55.4% aged ≥70 years; 36.6% females) were included in this study. In the pre-pandemic year of 2019, a total of 25,501 (13.2%) more hospitalizations due to PAD were detected compared to the COVID-19 pandemic year of 2020 (2019: 192,765 [53.4%] vs. 2020: 168,264 [46.6%], p = 0.065). Overall, in 610 (0.4%) of the hospitalization cases, a COVID-19 infection was diagnosed. Regarding interventional/surgical treatments, total numbers of peripheral endovascular intervention of the lower extremity decreased by 9.9% (83,845 vs. 75,519, p < 0.001), surgical peripheral artery revascularization of the lower extremity by 11.4% (32,447 vs. 28,754, p = 0.041) and amputations by 4.0% (20,612 vs. 19,784, p < 0.001) in 2020 compared to 2019. The case fatality rate (2.6% vs. 2.4%, p < 0.001), as well as MACCE rate (3.4% vs. 3.2%, p < 0.001), were slightly higher during the pandemic year 2020 compared to the pre-pandemic year 2019. Conclusions: The COVID-19 pandemic influenced the number of hospitalizations of PAD patients with a 13.2% reduction in hospital admissions and decreased total numbers of revascularization and amputation treatments.

Preoperative evaluation and perioperative management of patients undergoing major vascular surgery

Patients undergoing major vascular surgery have an increased risk of perioperative major adverse cardiovascular events (MACE). Accordingly, in this population, it is of particular importance to appropriately risk stratify patients' risk for these complications and optimize risk factors prior to surgical intervention. Comorbidities that portend a higher risk of perioperative MACE include coronary artery disease, heart failure, left-sided valvular heart disease, and significant arrhythmic burden. In this review, we provide a current approach to risk stratification prior to major vascular surgery and describe the strengths and weaknesses of different cardiac risk indices; discuss the role of noninvasive and invasive cardiac testing; and review perioperative pharmacotherapies.

Temporal trends in patients with peripheral artery disease influenced by diabetes mellitus in Germany

INTRODUCTION

In patients with peripheral artery disease (PAD) the presence of diabetes mellitus (DM) is associated with higher morbidity and mortality. Because huge efforts are made to improve medical care of patients with DM including chronic disease programs, the aim of the present study was to investigate temporal trends regarding the clinical burden of DM on PAD patients within a 15-year observational period.

METHODS

We analyzed all patients hospitalized because of PAD between 2005 and 2019 in Germany stratified regarding DM.

RESULTS

Overall, 2 654 871 hospitalizations of PAD patients (865 823 with DM) were included. Hospitalizations based on PAD inclined from 142 778 in 2005 to 190 135 in 2019 (β 3956 per year; 95% confidence interval [CI] 3034-4878, p < .001) with simultaneous increase of hospitalizations of PAD patients with DM (2005: 41609 (29.1%) versus 2019: 65 302 (34.3%); β 2019 per year [95% CI 1593-2446], p < .001). Amputation rates (β -0.42 [95% CI -0.44 to -0.40]; p < .001) as well as in-hospital case-fatality rate (2005: 4.7%, 2019: 2.8%; β -0.64 [95% CI -0.69 to -0.59]; p < .001) decreased in diabetic PAD patients during the observational time. In spite of improved morbidity and mortality in the last years of the observational period, patients with DM still suffered from an increased risk for morbidity and mortality during the observational period compared to nondiabetic PAD patients.

CONCLUSIONS

Despite the progress in DM treatments, DM still was associated with an unfavorable clinical patient profile and remained a substantial risk factor for morbidity and mortality in hospitalized patients with PAD and DM in Germany between 2005 and 2019.

Aortic calcification index predicts mortality and cardiovascular events in operatively treated patients with peripheral artery disease A prospective PUREASO cohort follow-up study

OBJECTIVE

Present study evaluates the association of aortic calcification to mortality and major adverse cardiovascular and leg events (MACE and MALE) in patients with peripheral artery disease (PAD). The risk for mortality and MACE and MALE events is considered in clinical decision making.

METHODS

This cohort found in 2012 - 2013 consists of 226 symptomatic PAD patients referred to Turku University Hospital for invasive treatment. Follow-up data about mortality and survival without MACEs and MALEs was collected up to 5 years from inclusion date and aortic calcification index (ACI) was measured from patients with available imaging studies (164 of 226). ACIs association with events and mortality was evaluated in Cox regression, Kaplan-Meier and Classification and regression tree analysis.

RESULTS

All-cause mortality at 1, 3 and 5 years was 13.7%, (31), 26.1% (59) and 46.9% (106), respectively. In multivariable Cox regression analysis ACI and ACI>43 were independent risk factors for all-cause mortality (HR 1.13 per 10 units 95%CI, 1.00-1.22 and HR 1.83, 95%CI, 1.01-3.32, respectively) and for MACE (HR 1.10 per 10 units, 95%CI, 1.00-1.22 and HR 3.14, 95%CI, 1.67-5.91, respectively), but not for MALES. Classification and regression tree analysis showed that ACI 43 best divides cohort in relation to mortality. Kaplan-Meier analyses showed that ACI>43 is associated with greater mortality and occurrence of MACEs compared to those who have ACI≤43 (log-rank p-value 0.005 and 0.0012, respectively).

CONCLUSION

Risk for mortality and MACEs is associated with high ACI. ACI can expose PAD patients' risk for further cardiovascular events and mortality.

Microvascular dysfunction and neurovascular uncoupling are exacerbated in peripheral artery disease, increasing the risk of cognitive decline in older adults

Peripheral artery disease (PAD) is a vascular pathology with high prevalence among the aging population. PAD is associated with decreased cognitive performance, but the underlying mechanisms remain obscure. Normal brain function critically depends on an adequate adjustment of cerebral blood supply to match the needs of active brain regions via neurovascular coupling (NVC). NVC responses depend on healthy microvascular endothelial function. PAD is associated with significant endothelial dysfunction in peripheral arteries, but its effect on NVC responses has not been investigated. This study was designed to test the hypothesis that NVC and peripheral microvascular endothelial function are impaired in PAD. We enrolled 11 symptomatic patients with PAD and 11 age- and sex-matched controls. Participants were evaluated for cognitive performance using the Cambridge Neuropsychological Test Automated Battery and functional near-infrared spectroscopy to assess NVC responses during the cognitive n-back task. Peripheral microvascular endothelial function was evaluated using laser speckle contrast imaging. We found that cognitive performance was compromised in patients with PAD, evidenced by reduced visual memory, short-term memory, and sustained attention. We found that NVC responses and peripheral microvascular endothelial function were significantly impaired in patients with PAD. A positive correlation was observed between microvascular endothelial function, NVC responses, and cognitive performance in the study participants. Our findings support the concept that microvascular endothelial dysfunction and neurovascular uncoupling contribute to the genesis of cognitive impairment in older PAD patients with claudication. Longitudinal studies are warranted to test whether the targeted improvement of NVC responses can prevent or delay the onset of PAD-associated cognitive decline.NEW & NOTEWORTHY Peripheral artery disease (PAD) was associated with significantly decreased cognitive performance, impaired neurovascular coupling (NVC) responses in the prefrontal cortex (PFC), left and right dorsolateral prefrontal cortices (LDLPFC and RDLPFC), and impaired peripheral microvascular endothelial function. A positive correlation between microvascular endothelial function, NVC responses, and cognitive performance may suggest that PAD-related cognitive decrement is mechanistically linked, at least in part, to generalized microvascular endothelial dysfunction and subsequent impairment of NVC responses.

Ex Vivo Evaluation of the Cranial Tibial Artery and Its Compression through Fragment Rotation during Tibia Plateau Levelling Osteotomy: An Angiographic Three-Dimensional Reconstruction

OBJECTIVE

 To illustrate the arterial vascularity of the proximal tibia three-dimensionally and to evaluate the impact of fragment rotation on the cranial tibial artery by tibia plateau levelling osteotomy (TPLO).

METHOD

 Radiographic angiography and computed tomography (CT) were performed on 12 pelvic limbs from six large-breed canine cadavers before and after TPLO. Three-dimensional (3D) models of the stifle, including osseous and vascular structures, were obtained, and the integrity of the cranial tibial artery was assessed. Post-TPLO CT images were used to analyze compression of the cranial tibial artery by the rotated fragment.

RESULTS

 The uncompressed cranial tibial artery caliber, measured proximally and distally to the osteotomy, was 9.52 mm² (6.07-18.90 mm²). In all adequately rotated fragments, the mean caliber of the artery on the level of the osteotomy was 1.57 mm² (0.89-2.93 mm²) after TPLO. This represented a significant decrease of approximately 81%. Only slight cross-sectional area decrease (8.8%) was seen in one limb, which was revealed to have insufficient fragment rotation (2.83 mm). Another limb only showed signs of stretching of the artery (31.51%), which was under-rotated and medially displaced. Pre-TPLO 3D reconstructions were mainly consistent with previous anatomic studies except for the distance between tibial cortex and cranial tibial artery, which appeared closer.

CONCLUSION

 Sufficient fragment rotation leads to compression of the cranial tibial artery. Intraoperative hemorrhage can be caused by laceration of the main cranial tibial artery or by multiple small branches reaching craniolaterally.

Pro-Calcific Environment Impairs Ischaemia-Driven Angiogenesis

Peripheral arterial disease (PAD) is characterised by accelerated arterial calcification and impairment in angiogenesis. Studies implicate vascular calcification as a contributor to PAD, but the mechanisms remain unclear. We aimed to determine the effect of calcification on ischaemia-driven angiogenesis. Human coronary artery endothelial cells (ECs) were treated with calcification medium (CM: CaCl₂ 2.7 mM, Na₂PO₄ 2.0 mM) for 24 h and exposed to normoxia (5% CO₂) or hypoxia (1.2% O₂; 5% CO₂ balanced with N₂). In normoxia, CM significantly inhibited tubule formation and migration and upregulated calcification markers of ALP, BMP2, and Runx2. CM elevated levels of calcification-protective gene OPG, demonstrating a compensatory mechanism by ECs. CM failed to induce pro-angiogenic regulators VEGFA and HIF-1α in hypoxia and further suppressed the phosphorylation of endothelial nitric oxide synthase (eNOS) that is essential for vascular function. In vivo, osteoprotegerin-deficient mice (OPG^−/−), a calcification model, were subjected to hind-limb ischaemia (HLI) surgery. OPG^−/− mice displayed elevated serum alkaline phosphatase (ALP) activity compared to wild-type controls. OPG^−/− mice experienced striking reductions in blood-flow reperfusion in both 8-week-old and 6-month-old mice post-HLI. This coincided with significant impairment in tissue ischaemia and reduced limb function as assessed by clinical scoring (Tarlov). This study demonstrated for the first time that a pro-calcific environment is detrimental to ischaemia-driven angiogenesis. The degree of calcification in patients with PAD can often be a limiting factor with the use of standard therapies. These highly novel findings require further studies for full elucidation of the mechanisms involved and have implications for the development of therapies to suppress calcification in PAD.

A PON for All Seasons: Comparing Paraoxonase Enzyme Substrates, Activity and Action including the Role of PON3 in Health and Disease

Paraoxonases (PONs) are a family of hydrolytic enzymes consisting of three members, PON1, PON2, and PON3, located on human chromosome 7. Identifying the physiological substrates of these enzymes is necessary for the elucidation of their biological roles and to establish their applications in the biomedical field. PON substrates are classified as organophosphates, aryl esters, and lactones based on their structure. While the established native physiological activity of PONs is its lactonase activity, the enzymes’ exact physiological substrates continue to be elucidated. All three PONs have antioxidant potential and play an important anti-atherosclerotic role in several diseases including cardiovascular diseases. PON3 is the last member of the family to be discovered and is also the least studied of the three genes. Unlike the other isoforms that have been reviewed extensively, there is a paucity of knowledge regarding PON3. Thus, the current review focuses on PON3 and summarizes the PON substrates, specific activities, kinetic parameters, and their association with cardiovascular as well as other diseases such as HIV and cancer.

The Nevada Peripheral Artery Disease Screening Effort in a Medicare Advantage Population and Subsequent Mortality and Major Adverse Cardiovascular Event Risk

INTRODUCTION

There is a lack of contemporary estimates of undetected asymptomatic lower-extremity peripheral artery disease (PAD) in the community and its association with adverse outcomes in the population. We aimed to study the long-term association between previously undetected PAD and subsequent all-cause mortality and major adverse cardiovascular events (MACE) in Medicare advantage beneficiaries 65 years and older in a large metropolitan area characterized by concentrations of atherosclerotic risk factors along with a more vulnerable socio-economic risk profile.

METHODS

Data was derived from electronic medical records and linked with claims outcomes data for 13,971 Medicare advantage beneficiaries 65 years and older who underwent PAD screening in 2016 as part of patients' routine annual health assessment in the greater Las Vegas, Nevada metropolitan area. PAD screenings were performed with their primary care provider using volume plethysmography system (VPS) methods. The association between PAD screen status and one-year and 3-year all-cause mortality and MACE rates was documented.

RESULTS

The cohort had a mean age of 75.3±6.6 years and 57.7% of them were female. A total of 4,351 out of 13,768 (31.6%) had a positive PAD screening result. Almost 60% had a lower socio-economic income level, with 15.1% living under the poverty level. The risk estimates associated with a positive vs. a negative PAD screening for both all-cause mortality and MACE was (unadjusted HR mortality=2.17, 95% Confidence Interval, 95%CI 1.79-2.63; unadjusted HR MACE=2.00, 95%CI 1.15-3.49) at 1 year, and (unadjusted HR mortality=2.04, 95%CI 1.84-2.26; unadjusted HR MACE=1.67, 95%CI 1.37-2.02) at 3 year, respectively. Following multivariable adjustment, all associations persisted (P-values <.001) ranging from 1.41-1.69, except for 1-year MACE (similar risk estimate, but P=0.09).

CONCLUSION

A positive screening result of previously undetected lower extremity PAD was independently associated with short-term and long-term increased risks for mortality and MACE in individuals aged 65 years and older living in a large, metropolitan area.

Predictors of long-term mortality in left-sided infective endocarditis: an historical cohort study in 414 patients

INTRODUCTION

Very limited data are available on the long-term outcome of infective endocarditis (IE) and its determinants. The aim of this study was to identify the predictors of long-term mortality in patients affected by left sided IE (LSIE).

METHODS

This was an historical retrospective observational study on prospectively collected data from patients with LSIE hospitalized in our Unit (January 2000-December 2017). Multiple variables relevant to history, physical examination, laboratory tests, echocardiography, comorbidities, complications and outcome were analysed by Cox regression to identify predictors of long-term mortality.

RESULTS

414 patients were included, and followed up for a median of 39 months [IQR 11-74]. Median age was 59 years [range 3-89], and most patients were male. Over 50% showed at least one comorbidity. Hyperglycaemia, increased creatinine and an indication for surgery predicted in-hospital mortality, while a prior myocardial infarction, chronic kidney disease (CKD) on hemodialysis and a larger vegetation were independent predictors of 1-year mortality. At multivariate analysis, peripheral arterial disease (p= 0.017), hyperglycemia on admission (p=0.013) and a higher BMI (p=0.009) were independent predictors of long-term mortality in 1-year survivors. At multivariable Cox proportional hazard regression, peripheral arterial disease (p=0.002), hyperglycemia (p=0.041) and CKD on hemodialysis (p=0.025) confirmed to be independently associated with an increased risk of long-term mortality in the overall 414 patient cohort.

CONCLUSIONS

Cardiovascular and metabolic risk signals, specifically peripheral arterial disease and hyperglicemia, affect long-term mortality of LSIE. An active and long-term follow up seems warranted in IE survivors showing these conditions at outset.