Tibial artery calcification as a marker of amputation risk in patients with peripheral arterial disease

Influence of a Novel Morphology-Driven Classification on Limb Salvage after Isolated Tibial Intervention for Chronic Limb Threatening Ischemia

BACKGROUND

Infra-popliteal interventions for chronic limb-threatening ischemia (CLTI) can be impacted by the morphology of the tibial vessels. The aim of this study was to examine the impact of a novel morphology-driven classification on the outcomes of isolated tibial intervention for CLTI.

METHODS

A database of patients undergoing isolated tibial interventions for CLTI at a single center between 2010 and 2020 was retrospectively queried. Patients with isolated infra-popliteal disease were identified, and their anatomy was scored as present or absent for lesion calcification (1 point), target vessel diameter<3.0 mm (1 point), lesion length>300 mm (1 point), and poor pedal runoff score (1 point). Patients were then divided into 3 groups: low risk (0 or 1 points), moderate risk (2 points), and high risk (3 or 4 points). Intention to treat analysis by the patient was performed. Limb-based patency (the absence of reintervention, occlusion, critical stenosis [>70%], or hemodynamic compromise with ongoing symptoms of CLTI as it related to the patency of the preoperatively determined target artery pathway) was assessed. Patient-oriented outcomes of amputation-free survival (AFS; survival without major amputation) and freedom from major adverse limb events (MALE; above ankle amputation of the index limb or major reintervention: new bypass graft, jump/interposition graft revision) were evaluated.

RESULTS

1,607 patients (55% male, average age 60 years, 3,846 vessels) underwent tibial intervention for CLTI. The majority of the patients were diabetic and of Hispanic origin. Morphologically, 27%, 31%, and 42% of the vessels were categorized as low risk, moderate risk, and high risk, respectively. There was a significant worsening of the infra-popliteal Global Limb Anatomic Staging System (GLASS) grading as the morphological risk increased. The 30-day major adverse cardiac events (MACE) were equivalent across the groups and were under the stated objective performance goal (OPG) of ≤10%. In contrast, both the 30-day MALE and the 30-day major amputations were significantly different across the groups, with the low-risk group remaining under the OPG of ≤9% and ≤4%, respectively, while the moderate risk and high risk exceeded the goal threshold. For the OPG, freedom from MALE was 60 ± 5%, 46 ± 5%, and 22 ± 9% at 5 years for low-, moderate-, and high-risk groups, respectively (mean ± standard error of the mean; P = 0.008). Overall AFS was 55 ± 5%, 37 ± 6%, and 18 ± 7% at 5 years for low-, moderate-, and high-risk groups, respectively (mean ± standard error of the mean; P = 0.003).

CONCLUSIONS

Tibial anatomic morphology impacts isolated tibial endovascular intervention with adverse morphology associated with poorer short- and long-term outcomes. Risk stratification based on anatomic predictors should be an additional consideration as one intervenes on infra-popliteal vessels for CLTI.

Pedal medial arterial calcification influences the outcomes of isolated infra-malleolar interventions for chronic limb-threatening ischemia

OBJECTIVE

Inframalleolar disease is present in most diabetic patients presenting with tissue loss. Inframalleolar (pedal) artery disease and pedal medial arterial calcification (pMAC) are associated with major amputation in patients with chronic limb-threatening ischemia (CLTI). This study aimed to examine the impact of pMAC on the outcomes after isolated inframalleolar (pedal artery) interventions.

METHODS

A database of lower extremity endovascular intervention for patients with tissue loss between 2007 and 2022 was retrospectively queried. Patients with CLTI were selected, and those undergoing isolated inframalleolar intervention on the dorsalis pedis and medial and lateral tarsal arteries and who had foot x-rays were identified. X-rays were assessed blindly for pMAC and scored on a scale of 0 to 5. Patients with concomitant superficial femoral artery and tibial interventions were excluded. Intention to treat analysis by the patient was performed. Amputation-free survival (survival without major amputation) was evaluated.

RESULTS

A total of 223 patients (51% female; 87% Hispanic; average age, 66 years; 323 vessels) underwent isolated infra-malleolar intervention for tissue loss. All patients had diabetes, 96% had hypertension, 79% had hyperlipidemia, and 63% had chronic renal insufficiency (55% of these were on hemodialysis). Most of the patients had Wound, Ischemia, and foot Infection (WIfI) stage 3 disease and had various stages of pMAC: severe (score = 5) in 48%, moderate (score = 2-4) in 31%, and mild (score = 0-1) in 21% of the patients. Technical success was 94%, with a median of one vessel treated per patient. All failures were in severe pMAC. Overall, major adverse cardiovascular events was 0.9% at 90 days after the procedure. Following the intervention, most patients underwent a planned forefoot amputation (single digit, multiple digits, ray amputation, or trans-metatarsal amputation). WIfI ischemic grade was improved by 51%. Wound healing at 3 months was 69%. Those not healing underwent below-knee amputations. The overall 5-year amputation-free survival rate was 35% ± 9%. The severity of pMAC was associated with decreased AFS.

CONCLUSIONS

Increasing severity of pMAC influences the technical and long-term outcomes of infra-malleolar intervention in diabetes. Severe pMAC is associated with amputation and should be considered as a variable in the shared decision-making of diabetic patients with CLTI.

A prospective observational study to evaluate a possible relationship between vitamin K antagonist therapy and risk of peripheral arterial disease in patients with type 2 diabetes

AIM

The use of vitamin K antagonists (VKAs) may increase the risk of peripheral arterial disease (PAD) because vitamin K is a strong inhibitor of medial arterial calcification. Type 2 diabetes (T2D) exposes patients to an increased risk of PAD. We examined how the use of VKAs modulates the risk of incident PAD in people with T2D.

MATERIALS AND METHODS

SURDIAGENE is a French cohort including 1468 patients with T2D with a prospective follow-up from 2002 to 2015. The primary outcome of the current analysis was the first occurrence of PAD, a composite of lower-limb amputation (LLA) or lower-limb revascularization. LLA and lower-limb revascularization were considered individually as secondary outcomes.

RESULTS

During a 7-year median follow-up, PAD occurred in 147 (10%) of the 1468 participants. The use of VKAs was not significantly associated with the risk of PAD [multivariable adjusted hazard ratio (HR) 1.42, 95% confidence interval (CI), 0.88-2.31]. During the study period, LLA and lower-limb revascularization occurred in 82 (6%) and 105 (7%) participants, respectively. The use of VKAs was significantly associated with increased risk of LLA [multivariable adjusted HR 1.90 (95% CI, 1.04-3.47)], but not lower-limb revascularization [multivariable adjusted HR 1.08 (95% CI, 0.59-1.97)].

CONCLUSIONS

In this prospective study, we did not observe any excess risk of PAD requiring lower-limb revascularization in people with type 2 diabetes using VKAs. However, our data suggest a high risk of LLA in VKA users. Further studies are required to confirm this observation.

Effect of Doxycycline on Progression of Arterial Calcification in the Noninvasive Treatment of Abdominal Aortic Aneurysm Clinical Trial (N-TA(3)CT)

BACKGROUND

Doxycycline has been shown to prevent arterial calcification via attenuation of matrix metalloproteinases (MMP) in preclinical models. We assessed the effects of doxycycline on progression of arterial calcification in patients enrolled in the Non-Invasive Treatment of Abdominal Aortic Aneurysm Clinical Trial (N-TA3CT).

METHODS

Two hundred and sixty-one patients were randomized to 100 mg doxycycline twice daily or placebo. Arterial calcification was measured in abdominal vessels on noncontrast computed tomography scans. Patients with baseline computed tomography scan and 1 or more follow-up scans within the 2-year study were included for analysis. For individual arteries, mean change in iliofemoral artery calcification over time was calculated via linear regression. Serum MMP-3 and MMP-9 levels were measured at baseline and 6 months.

RESULTS

Sixty-five patients in the doxycycline and 66 in the placebo arm were included in this analysis. Baseline characteristics between the groups were similar. The unadjusted mean change in iliofemoral calcium score per year trended toward higher values in patients treated with doxycycline compared with placebo (322 ± 399 units/year vs. 217 ± 307 units/year, P = 0.09). After 6 months, changes in serum MMP-3 and MMP-9 levels were not significantly different between study arms.

CONCLUSIONS

In patients with small aortic aneurysm, treatment with doxycycline 100 mg twice daily did not decrease circulating levels of the matrix degrading enzymes MMP-3 and 9 or alter the progression of arterial calcification.

Anatomical and clinical factors associated with infrapopliteal arterial bypass outcomes in patients with chronic limb-threatening ischemia

The aim of this study was to identify anatomical and clinical factors associated with limb-based patency (LBP) loss, major adverse limb events (MALEs), and poor amputation-free survival (AFS) after an infrapopliteal arterial bypass (IAB) surgery according to the Global Limb Anatomic Staging System. A retrospective analysis of patients undergoing IAB surgery between January 2010 and December 2021 at a single institution was performed. Two-year AFS, freedom from LBP loss, and freedom from MALEs were assessed using the Kaplan-Meier method. Anatomical and clinical predictors were assessed using multivariate analysis. The total number of risk factors was used to calculate risk scores for subsequent categorization into low-, moderate-, and high-risk groups. IABs were performed on 103 patients. The rates of two-year freedom from LBP loss, freedom from MALEs, and AFS were 71.3%, 76.1%, and 77.0%, respectively. The multivariate analysis showed that poor run-off beyond the ankle and a bypass vein caliber of < 3 mm were significantly associated with LBP loss and MALEs. Moreover, end-stage renal disease, non-ambulatory status, and a body mass index of < 18.5 were significantly associated with poor AFS. The rates of freedom from LBP loss and MALEs and the AFS rate were significantly lower in the high-risk group than in the other two groups (12-month low-risk rates: 92.2%, 94.8%, and 94.4%, respectively; 12-month moderate-risk rates: 58.6%, 84.6%, and 78.3%, respectively; 12-month high-risk rates: 11.1%, 17.6%, and 56.2%, respectively; p < 0.001, p < 0.001, and p < 0.001, respectively). IAB is associated with poor clinical outcomes in terms of LBP, MALEs, and AFS in high-risk patients. Risk stratification based on these predictors is useful for long-term prognosis.

Smooth muscle cell-specific matrix metalloproteinase 3 deletion reduces osteogenic transformation and medial artery calcification

AIMS

Vascular calcification is highly prevalent in atherosclerosis, diabetes, and chronic kidney disease. It is associated with increased morbidity and mortality in patients with cardiovascular disease. Matrix metalloproteinase 3 (MMP-3), also known as stromelysin-1, is part of the large matrix metalloproteinase family. It can degrade extracellular matrix components of the arterial wall including elastin, which plays a central role in medial calcification. In this study, we sought to determine the role of MMP-3 in medial calcification.

METHODS AND RESULTS

We found that MMP-3 was increased in rodent models of medial calcification as well as in vascular smooth muscle cells (SMCs) cultured in a phosphate calcification medium. It was also highly expressed in calcified tibial arteries in patients with peripheral arterial disease (PAD). Knockdown and inhibition of MMP-3 suppressed phosphate-induced SMC osteogenic transformation and calcification, whereas the addition of a recombinant MMP-3 protein facilitated SMC calcification. In an ex vivo organ culture model and a rodent model of medial calcification induced by vitamin D3, we found that MMP-3 deficiency significantly suppressed medial calcification in the aorta. We further found that medial calcification and osteogenic transformation were significantly reduced in SMC-specific MMP-3-deficient mice, suggesting that MMP-3 in SMCs is an important factor in this process.

CONCLUSION

These findings suggest that MMP-3 expression in vascular SMCs is an important regulator of medial calcification and that targeting MMP-3 could provide a therapeutic strategy to reduce it and address its consequences in patients with PAD.

Clinical Utility of Infrapopliteal Calcium Score for the Evaluation of Severity of Peripheral Artery Disease

PURPOSE

To identify associations between computed tomography (CT)-based lower-extremity calcium score (LECS) across different anatomic segments and the presence, severity, and clinical outcomes of peripheral artery disease (PAD).

MATERIALS AND METHODS

In a mixed retrospective and prospective cohort study, 139 patients without prior lower-extremity intervention who underwent CT angiography of the aorta and lower extremities were identified. Subjects were classified as asymptomatic, claudicants, or having chronic limb-threatening ischemia (CLTI). LECS was measured using the Agatston method. Univariate and multivariate analyses were performed across categories of PAD severity. Receiver operating characteristic (ROC) analysis was performed, and an optimal cutoff point for LECS was identified. Claudicants were followed prospectively for CLTI and mortality.

RESULTS

Higher infrapopliteal calcium score (CS) was independently associated with CLTI versus claudication (odds ratio [OR], 3.24 per unit increase in log10-transformed CS; P < .001) in addition to hemodialysis dependence and poor functional status. One hundred eighty-eight Agatston units was identified as the optimal cutoff for infrapopliteal CS in assessing the risk of CLTI versus claudication (area under the ROC curve, 0.84 [SD ± 0.049]). This cutoff was validated in an independent cohort to be associated with progression to CLTI (OR, 12.8; P = .0039). In the claudicant group followed prospectively, infrapopliteal CS ≥188 predicted increased risk of CLTI or death after adjusting for functional status and hemodialysis dependence (Cox hazard ratio, 4.92; P = .0202).

CONCLUSIONS

Higher infrapopliteal CS was associated with CLTI among those with symptomatic PAD. An infrapopliteal CS cutoff of 188 Agatston units may serve as a useful tool to identify patients with increased risk of CLTI and mortality.

An ultrasound-based femoral artery calcification score

Objective

Duplex ultrasound (US) of the lower extremities is commonly used to assess patients with lower extremity atherosclerosis. Arterial calcification can often be visualized in these images; however, efforts to quantify its extent have been limited. We, thus, sought to develop a new scoring system to measure calcification on duplex US studies of the femoral artery and correlate it with standard computed tomography (CT)-based methods. We then made preliminary attempts to correlate US-based femoral artery calcification scores with limb-specific outcomes in patients with peripheral arterial disease.

Methods

Patients who underwent CT evaluation of the lower extremities and arterial duplex US of either lower extremity within 6 months of each examination were included in the study. CT-based calcium scores of the femoral artery were generated using calcium scoring software. To determine the US score, five standard arterial segments (ie, common femoral artery, proximal superficial femoral artery [SFA], mid-SFA, distal SFA, and above the knee popliteal artery) were scored using a scale of 0 to 2 (0, a completely normal vessel segment; 1, a vessel with hyperechoic irregularities of the vessel wall; and 2, clear anechoic shadowing). The available scores were then averaged to yield a single femoral calcium score for each leg. Predictors of femoral calcification scores were then assessed and compared with the CT-based methods. The correlation between the US- and CT-based femoral calcification was assessed, and then the association between the US-based femoral calcification score and limb outcomes was evaluated.

Results

A total of 113 patients met the inclusion criteria and were included in the final analysis. US-based calcification scores were increased in patients with diabetes, renal failure, and the presence of chronic limb threatening ischemia similar to CT-based femoral calcification. The US- and CT-based calcification scores showed a moderate to strong correlation (r = 0.64). An elevated US-based femoral artery calcification score was associated with decreased amputation-free survival.

Conclusions

A novel US-based method shows promise as a simple method for quantifying the extent of femoral artery calcification in patients with peripheral arterial disease. The US-based method correlates with standard CT-based methods. Preliminary studies show that it could be useful for predicating outcomes for patients with peripheral arterial disease.

Circumferential degree of tibial artery calcification is associated with infrapopliteal endovascular revascularization outcomes in patients with chronic limb-threatening ischemia

BACKGROUND

Tibial artery calcification (TAC) is correlated with an increased risk of amputation and mortality in patients with chronic limb-threatening ischemia (CLTI). The association between calcification characteristics and adverse limb events of CLTI. However, it has not been assessed. This study aims to assess the relationship between the characteristics of TAC based on computed tomography angiography (CTA) scans and postoperative outcomes in patients with CLTI undergoing infrapopliteal endovascular therapy.

METHODS

This was a retrospective study of patients who underwent infrapopliteal endovascular revascularization for CLTI and had a preoperative CTA scan. Based on CTA, TAC was divided into the following categories: annularity, thickness, continuity and severity. Cox regression models using generalized estimating equations were performed to assess the relationship between calcification characteristics and postoperative outcomes. The outcomes evaluated were the occurrence of all cause mortality (ACM) and unplanned amputation.

RESULTS

Among the 148 patients undergoing endovascular, there were 50 (33.8%) patients died and 26 (17.6%) patients underwent unplanned amputation. Annular calcification was more common in the ACM group than in the non-ACM group. No significant differences were found between the two groups with regard to the probability of calcification in the thickness and the continuity (P>0.05). Patients in the unplanned amputation group had significantly annular, thin and continuity calcifications (P<0.05) than those in the non-unplanned amputation group. The presence of annular calcification was an independent predictor of ACM (hazard ratio (HR), 3.186; 95% confidence interval (CI), 1.781-5.702; P<0.001) and unplanned amputation (HR, 3.739; 95% CI, 1.707-8.191; P<0.05).

CONCLUSIONS

Among patients with CLTI, the occurrence of annular calcification in the tibial artery are related to a greater chance of ACM and unplanned amputation in the postoperative period. The circumferential degree of TAC of the operated limb can be considered as a marker of clinical prognosis in this group of patients.

Ultrasound-detected tibial artery calcification as a marker of cardiovascular and lower-limb risk in asymptomatic patients with type-2 diabetes

BACKGROUND

Medial arterial calcification (MAC) is a vascular disease distinct from atherosclerosis. Recently, several studies have demonstrated that MAC is an important marker of cardiovascular events. We aim to assess the presence of MAC during ultrasound screening of lower-limb vasculature and its association with both cardiovascular (CV) and lower-limb events in patients with type-2 diabetes.

METHODS

A retrospective cohort study was conducted on 1119 patients with type-2 diabetes free from CV disease. A CV work-up, including vascular ultrasound, was performed for each patient. The presence of MAC was assessed on posterior tibial arteries and ankle-brachial index (ABI) was measured. Major acute CV events (MACEs) and lower-limb events (MALEs) were recorded as a composite endpoint for a 5-year period.

RESULTS

We identified MAC among 212 (18.9%) patients. The independent determinants of MAC were age and diabetic retinopathy. Over a period of 5 years, 125 MACEs and 22 MALEs occurred. MAC was significantly associated with the composite outcome MACE + MALE (HR = 1.94; 95% CI: 1.23, 3.08, p = 0.005) or with MACE (HR = 1.85; 95% CI: 1.16, 2.95, p = 0.010). Adjusted for ABI and diabetic foot wound, MAC remained a determinant of MALE (HR = 5.49; 95% CI: 2.19, 13.76, p < 0.001). Considering each ABI group, MAC was associated with both MACE and MALE in the normal ABI group.

CONCLUSIONS

Ultrasound-detected MAC on tibial arteries seems to be a determinant of both CV and lower-limb events, independent from ABI. MAC helps to refine the CV risk in patients with normal ABI.

Medial arterial calcification score is associated with increased risk of major limb amputation

OBJECTIVE

The pedal medial arterial calcification (MAC) score has been associated with risk of major limb amputation in patients with chronic limb-threatening ischemia. This study aimed to validate the pedal MAC scoring system in a multi-institutional analysis to validate its usefulness in limb amputation risk prediction.

METHODS

A multi-institution, retrospective study of patients who underwent endovascular or open surgical infrainguinal revascularization for chronic limb-threatening ischemia was performed. MAC scores of 0 to 5 were assigned based on visible calcified arteries on foot X ray then trichotomized (0-1, 2-4, 5) for analysis. The primary outcome was major limb amputation at 6 months. Adjusted Kaplan-Meier models were used to analyze time-to-major amputation across groups.

RESULTS

There were 176 patients with 184 affected limbs (mean age, 66 years; 61% male; 60% White), of whom 97% presented with a wound. The MAC score was 0 in 41%, 1 in 9%, 2 in 13%, 3 in 11%, 4 in 13%, and 5 in 13% of the limbs. There were 26 major amputations (14%) and 16 deaths (8.7%) within 6 months. Patients with MAC 5 had a significantly higher risk of major limb amputation than both the 0 to 1 and 2 to 4 groups (P = .001 and P = .044, respectively), and lower overall amputation-free survival (log-rank P = .008).

CONCLUSIONS

Pedal MAC score is a reproducible and generalizable measure of inframalleolar arterial disease that can be used with Wound, Ischemia, and foot Infection staging to predict major limb amputation in patients with chronic limb-threatening ischemia.

Evaluation of Lower Extremity Calcium Score as a Measure of Peripheral Arterial Disease Burden and Amputation Risk

BACKGROUND

The ankle-brachial pressure index (ABI) and toe-brachial pressure index (TBI) are commonly used diagnostic tools for peripheral artery disease (PAD) that are unreliable in the presence of calcified vessels. In this study, we aimed to demonstrate the utility of the lower extremity calcium score (LECS) in addition to ABI and TBI in measuring disease burden and predicting the risk of amputation in patients with PAD.

METHODS

Patients who were evaluated in the vascular surgery clinic at Emory University for PAD and who underwent noncontrast computed tomography of the aorta and lower extremities were included in the study. Aortoiliac, femoral-popliteal, and tibial calcium scores were measured using the Agatston method. ABI and TBI that were obtained within 6 months of the computed tomography scan were noted and divided into categories of PAD severity. Associations between ABI, TBI, and LECS of each anatomic segment were evaluated. Univariate and multivariate ordinal regression analyses were performed to predict the outcome of amputation. Receiver operating characteristic analysis was performed to compare LECS with other variables in its ability to predict amputation.

RESULTS

Fifty patients included in the study cohort were divided into LECS quartiles, with 12-13 patients in each quartile. The highest quartile tended to be older (P = 0.016), had a higher percentage of diabetics (P = 0.034), and had a higher frequency of major amputations (P = 0.004) compared to the other quartiles. Patients in the highest quartile of tibial calcium score were more likely to have stage 3 chronic kidney disease (CKD) or greater (P = 0.011) and also had a higher frequency of amputation (P < 0.005) and mortality (P = 0.041). We found no significant association between each anatomic LECS and ABI/TBI categories. On univariate analysis, CKD (Odds Ratio [OR] 12.92 (95% CI 2.01 to 82.83), P = 0.007), diabetes mellitus (OR 5.47 (95% CI 1.27 to 23.64), P = 0.023), tibial calcium score (OR 6.62 (95% CI 1.79 to 24.54), P = 0.005), and total bilateral calcium score (OR 6.32 (95% CI 1.18 to 33.78), P = 0.031) were associated with increased risk of amputation. On multivariate stepwise ordinal regression, TBI and tibial calcium score were identified as important predictors of amputation, with hyperlipidemia and CKD increasing the overall prediction of the model. On Receiver operating characteristic analysis, the addition of the tibial calcium score (area under the curve 0.94, standard error 0.048) significantly improved the prediction of amputation compared to hyperlipidemia, CKD, and TBI alone (area under the curve 0.82, standard error 0.071, P = 0.022).

CONCLUSIONS

The addition of tibial calcium score to other known PAD risk factors may improve the prediction of amputation in patients with PAD.

Human Cadaveric Model for Vessel Preparation Device Testing in Calcified Tibial Arteries

To describe an ex vivo model for vessel preparation device testing in tibial arteries. We performed orbital atherectomy (OA), intravascular lithotripsy (IVL), and plain balloon angioplasty (POBA) on human amputated limbs with evidence of concentric tibial artery calcification. The arterial segments were then harvested for ex vivo processing which included imaging with microCT, decalcification, and histology. The model was tested out in 15 limbs and was successful in 14 but had to be aborted in 1/15 case due to inability to achieve wire access. A total of 22 lesions were treated with OA on 3/22 lesions, IVL on 8/22, and POBA without vessel preparation on the remaining 11/22. Luminal gain was assessed with intravascular ultrasound and histology was able to demonstrate plaque disruption, dissections, and cracks within the calcified lesions. A human cadaveric model using amputated limbs is a feasible, high-fidelity option for evaluating the performance of vessel preparation devices in calcified tibial arteries.

Treatment of Difficult, Calcified Lesions: Plaque Modification Strategies

Endovascular management of peripheral arterial disease is continually evolving. Most changes focus on addressing the challenges that hinder optimal patient outcomes; one of the most significant is how to best treat calcified lesions. Hardened plaque results in a variety of technical issues including impaired device delivery, decreased luminal revascularization, poor stent expansion, heightened risk of in-stent stenosis or thrombosis, and increased procedural time and cost. For this reason, plaque modification devices have been developed to mitigate this issue. This paper will describe these strategies and provide the reader with an overview of devices that can be used to treat chronically hardened lesions.

Detection of Multi-Vessel Calcific Disease Progression in a Patient with Chronic Limb-Threatening Ischemia Using 18F-Sodium Fluoride Positron Emission Tomography Imaging

Vascular calcification contributes to morbidity and poor clinical outcomes for patients with peripheral artery disease; however, the traditional assessment of the calcium burden using computed tomography (CT) imaging or angiography represents already established disease. In the present report, we describe a 69-year-old man with chronic limb-threatening ischemia who had undergone positron emission tomography/CT imaging with fluorine-18 sodium fluoride to evaluate the relationship between baseline levels of positron emission tomography-detectable active vascular microcalcification and CT-detectable calcium progression 1.5 years later. CT imaging at follow-up identified progression of existing lesions and the formation of new calcium in multiple arteries that had demonstrated elevated fluorine-18 sodium fluoride uptake 1.5 years earlier.

Intravascular Lithotripsy in Calcified Peripheral Lesions: Single-Center JEN-Experience

Peripheral artery disease (PAD) shows increasing need for revascularization therapy. Interventional success in calcified lesions is limited. Here, intravascular lithotripsy (IVL), modifying intimal and medial calcium, is a promising treatment approach. A single-center, prospective all-comers registry for patients undergoing peripheral IVL was established to examine treatment success in PAD with severe vessel calcification. Periprocedural safety events as well as short-term and intermediate follow-up clinical data were evaluated. Between December 2018 and January 2021 all consecutive patients receiving peripheral lithotripsy at our center were analyzed. Clinical and angiographic data were evaluated. Angiographic images were analyzed using a semiautomatic software for quantitative vessel analysis. Eighty-five lesions in 61 limbs were treated with IVL in 51 patients presenting with Rutherford classes 2 to 5. Most lesions (68%) were localized in the superficial femoral artery. Mean calcified lesion length was 102.5 mm (10-390 mm), with a median peripheral arterial calcium score of 3, indicating a highly calcified status. In 58% of the patients, IVL was used as a stand-alone therapy. IVL resulted in a mean acute luminal gain of 2.6 ± 0.9 mm, resulting in stenosis reduction by 42.1 ± 15%. Mean ankle brachial index (ABI) improved significantly from 0.6 to 0.8 ( p  < 0.0001) on day 1 after the intervention and remained stable at 6 months. This large real-world data of peripheral IVL reports compelling safety in a complex patient cohort. For the first time, clinical follow-up data demonstrated a sustained significant improvement in ABI after 6 months.

Medial artery calcification in peripheral artery disease

Medial artery calcification (MAC) is a distinct, highly regulated process that is often identified in small and mid-sized arteries of the lower extremities. It is associated with advanced age, diabetes, and chronic kidney disease. MAC often occurs in conjunction with atherosclerotic occlusive disease in lower extremity arteries, and when seen together or in isolation, long-term limb outcomes are negatively affected. In patients with peripheral artery disease (PAD), the extent of MAC independently correlates with major amputation and mortality rates, and it predicts poor outcomes after endovascular interventions. It is associated with increased arterial stiffness and decreased pedal perfusion. New endovascular methods aimed at treating calcified lower-extremity lesions may improve our ability to treat patients with limb-threatening ischemia. Although recent developments have increased our understanding of the mechanisms contributing to MAC, further investigations are needed to understand the role of medial calcification in PAD, and to develop strategies aimed at improving patient outcomes.

Vessel-by-vessel analysis of lower extremity 18F-NaF PET/CT imaging quantifies diabetes- and chronic kidney disease-induced active microcalcification in patients with peripheral arterial disease

BACKGROUND

Positron emission tomography (PET)/computed tomography (CT) imaging with fluorine-18 (¹⁸F)-sodium fluoride (NaF) provides assessment of active vascular microcalcification, but its utility for evaluating diabetes mellitus (DM)- and chronic kidney disease (CKD)-induced atherosclerosis in peripheral arterial disease (PAD) has not been comprehensively evaluated. This study sought to use ¹⁸F-NaF PET/CT to quantify and compare active microcalcification on an artery-by-artery basis in healthy subjects, PAD patients with or without DM, and PAD patients with or without CKD. Additionally, we evaluated the contributions of DM, CKD, statin use and established CT-detectable calcium to ¹⁸F-NaF uptake for each lower extremity artery.

METHODS

PAD patients (n = 48) and healthy controls (n = 8) underwent lower extremity ¹⁸F-NaF PET/CT imaging. Fused PET/CT images guided segmentation of arteries of interest (i.e., femoral-popliteal, anterior tibial, tibioperoneal trunk, posterior tibial, and peroneal) and quantification of ¹⁸F-NaF uptake. ¹⁸F-NaF uptake was assessed for each artery and compared between subject groups. Additionally, established calcium burden was quantified for each artery using CT calcium mass score. Univariate and multivariate analyses were performed to evaluate DM, CKD, statin use, and CT calcium mass as predictors of ¹⁸F-NaF uptake in PAD.

RESULTS

PAD patients with DM or CKD demonstrated significantly higher active microcalcification (i.e., ¹⁸F-NaF uptake) for all arteries when compared to PAD patients without DM or CKD. Univariate and multivariate analyses revealed that concomitant DM or CKD was associated with increased microcalcification for all arteries of interest and this increased disease risk remained significant after adjusting for patient age, sex, and body mass index. Statin use was only associated with decreased microcalcification for the femoral-popliteal artery in multivariate analyses. Established CT-detectable calcium was not significantly associated with ¹⁸F-NaF uptake for 4 out of 5 arteries of interest.

CONCLUSIONS

¹⁸F-NaF PET/CT imaging quantifies vessel-specific active microcalcification in PAD that is increased in multiple lower extremity arteries by DM and CKD and decreased in the femoral-popliteal artery by statin use. ¹⁸F-NaF PET imaging is complementary to and largely independent of established CT-detectable arterial calcification. ¹⁸F-NaF PET/CT imaging may provide an approach for non-invasively quantifying vessel-specific responses to emerging anti-atherogenic therapies or CKD treatment in patients with PAD.

The posterior tibial artery free flap for head and neck reconstruction

PURPOSE

The posterior tibial artery free flap (PTAFF) has been a mainstay of lower extremity reconstruction. Over the past 30 years, it has been intermittently used for head and neck reconstruction with recent renewed interest given its versatility.

RECENT FINDINGS

Use of the PTAFF in head and neck reconstruction is expanding along with the continued evolution of microvascular techniques. Differences in overall health, incidence of smoking, and body habitus can impact the utility of this flap and should be taken into consideration when choosing to use it.

SUMMARY

The PTAFF for head and neck reconstruction is a useful tool for the head and neck/reconstructive surgeon. Understanding the potential pitfalls and caveats to use of the PTAFF is important for successful use of this versatile flap.

Responsiveness and Inter-Rater Reliability of the Pulse Volume Recording Upstroke Ratio (PVRr)

The objective of this study was to evaluate a measure of the responsiveness and reliability of the pulse volume recording upstroke ratio (PVRr). A database of 389 subjects undergoing lower extremity revascularization was analyzed. Subjects were included in the analysis if they had undergone pedal radiographs, had PVRs performed pre- and postlower extremity revascularization, and had regular pulsatile digital waveforms with a pressure recording on both PVRs. The responsiveness of the PVRr was assessed by means of the postoperative percent change in comparison to the digital pressures. A statistically significant negative correlation was observed (Pearson -0.421; p = .007) indicating that as digital pressures increased, the PVRr decreased. Further, measurement of the reliability of the PVRr was performed on a selection of 10 recordings by 2 residents and 3 board-certified surgeons. The observed intraclass correlation coefficient of measurements was 0.960. Results of this investigation provide evidence in support of the responsiveness and inter-rater reliability in the calculation of the pulse volume recording upstroke ratio.

Predicting Stenosis Aggravation in Follow-Up High-Resolution Magnetic Resonance Images of Patients with Intracranial Atherosclerosis

BACKGROUND

High-resolution magnetic resonance imaging (HRMRI) can provide information on the histopathological characteristics of intracranial atherosclerotic lesions causing arterial stenosis; however, its clinical application in intracranial atherosclerosis lacks standardization for predicting stenosis. Therefore, this study investigated the characteristics of HRMRI that can predict progression based on comparisons of follow-up HRMRI.

METHODS

We retrospectively enrolled patients who underwent HRMRI within 7 days of symptom onset to evaluate the characteristics associated with intracranial stenotic lesions. Among them, patients diagnosed with severe stenosis due to atherosclerosis and who underwent follow-up HRMRI 12-24 months after initial HRMRI were included in the final study. We analyzed distinct features, such as stenosis aggravation, the presence of initial plaque enhancement, increment of plaque enhancement, the existence of both eccentric and concentric plaques, and the presence of initial intraplaque hematoma on initial and follow-up HRMRI.

RESULTS

Among 442 patients who underwent HRMRI for severe stenosis due to atherosclerosis, 35 underwent follow-up HRMRI 12-24 months later. Patients with stenosis aggravation showed a higher incidence of plaque enhancement (87.5% vs. 3.7%, p < 0.001) and the presence of both concentric and eccentric plaques (75.0% vs. 11.1%; p = 0.001). The area under the curve for the increment of plaque enhancement was 0.92 (95% confidence interval [CI] 0.78-1.00, p ≤ 0.001), while that for the presence of both concentric and eccentric plaques was 0.82 (95% CI 0.63-1.00, p < 0.007).

CONCLUSIONS

The presence of both concentric and eccentric plaques and an increase in plaque enhancement were the strongest predictors of aggravation of intracranial artery stenosis.

Approximation of the Ankle-Brachial Index in the Setting of Medial Arterial Calcific Sclerosis

The presence of medial arterial calcific sclerosis is known to cause inaccuracy in the interpretation of noninvasive vascular testing. This substantially limits the utility of an important baseline diagnostic test for peripheral arterial disease. Therefore, the objective of this investigation was to derive a method to effectively factor out calcification in the interpretation of the ankle and digital brachial indices. The noninvasive vascular testing results of 160 subjects were stratified into the absence of calcification, mild calcification, moderate calcification, and severe calcification based on plain film radiographic findings of the infrageniculate vessels. Measurements were then performed of the pulse volume recording (PVR) waveforms at brachial, ankle and digital anatomic levels to include PVR wavelength and PVR upstroke length, with a calculation of the ratio of PVR upstroke length to PVR wavelength. These measurements were compared between groups and then correlated to the ankle and digital brachial indices. A significant difference was observed in the PVR upstroke ratio between the 3 anatomic levels (0.1818 vs 0.2622 vs 0.3191; p < .001), but not between the 4 calcification groups (0.2457 vs 0.2363 vs 0.2694 vs 0.2631; p = .242). A significant negative correlation was observed between the PVR upstroke ratio and the ankle brachial index (ABI) (Pearson -0.454; p = .002) with linear regression indicating the relationship is defined by the formula: Effective ankle brachial index = 1.17 - (1.33 × PVR upstroke ratio at ankle level). A significant negative correlation was also observed between the PVR upstroke ratio and the digital brachial index (Pearson -0.553; p < .001) with linear regression indicating the relationship is defined by the formula: Effective toe brachial index = 1.04 - (1.61 × PVR upstroke ratio at digital level). The results of this investigation demonstrate the feasibility of, and provide equations to approximate, the effective ankle brachial and toe brachial indices in the setting of medial arterial calcification.

Quantification of Calcium in Peripheral Arteries of the Lower Extremities: Comparison of Different CT Scanners and Scoring Platforms

OBJECTIVES

The aim of this study was to investigate the interscanner and interscoring platform variability of calcium quantification in peripheral arteries of the lower extremities.

MATERIALS AND METHODS

Twenty human fresh-frozen legs were scanned using 3 different computed tomography (CT) scanners. The radiation dose (CTDIvol) was kept similar for all scanners. The calcium scores (Agatston and volume scores) were quantified using 4 semiautomatic scoring platforms. Comparative analysis of the calcium scores between scanners and scoring platforms was performed by using the Friedman test; post hoc analysis was performed by using the Wilcoxon signed rank test with Bonferroni correction.

RESULTS

Sixteen legs had calcifications and were used for data analysis. Agatston and volume scores ranged from 12.1 to 6580 Agatston units and 18.2 to 5579 mm3. Calcium scores differed significantly between Philips IQon and Philips Brilliance 64 (Agatston: 19.5% [P = 0.001]; volume: 14.5% [P = 0.001]) and Siemens Somatom Force (Agatston: 18.1% [P = 0.001]; volume: 17.5% [P = 0.001]). The difference between Brilliance 64 and Somatom Force was smaller (Agatston: 5.6% [P = 0.778]; volume: 7.7% [P = 0.003]). With respect to the interscoring platform variability, OsiriX produced significantly different Agatston scores compared with the other 3 scoring platforms (OsiriX vs IntelliSpace: 14.8% [P = 0.001] vs Syngo CaScore: 13.9% [P = 0.001] vs iX viewer: 13.2% [P < 0.001]). For the volume score, the differences between all scoring platforms were small ranging from 2.9% to 4.0%. Post hoc analysis showed a significant difference between OsiriX and IntelliSpace (3.8% [P = 0.001]).

CONCLUSIONS

The use of different CT scanners resulted in notably different Agatston and volume scores, whereas the use of different scoring platforms resulted in limited variability especially for the volume score. In conclusion, the variability in calcium quantification was most evident between different CT scanners and for the Agatston score.

Calcium Score Predicts Mortality After Revascularization in Critical Limb Ischemia

PURPOSE

The calcium score is a measure of vessel wall calcification and has clinical applications when studied in different vascular beds. The presence of vascular calcification in the arteries of the lower limbs is very common in patients with peripheral arterial disease; however, its relationship with the postoperative outcomes in patients undergoing lower limb revascularization is still poorly studied. The aim of this study is to evaluate association between the calcium score of lower limbs and the postoperative outcomes in patients with peripheral arterial disease undergoing revascularization procedures.

METHODOLOGY

We retrospectively analyzed 88 lower limb revascularization procedures in 72 patients with critical limb ischemia who had enhanced computed tomography for preoperative evaluation. The calcium score was calculated, from the angiographic phase of preoperative computed tomography, in the segments of the aorta, iliac, femoropopliteal, and infrapopliteal. It was also calculated the calcium score of the operated limb, and the total calcium score using a standardized method. The outcomes evaluated were the occurrence of acute myocardial infarction, amputation, patency, technical success, and death from any cause. Patients were followed up through a 12 month period.

RESULTS

Among the 88 procedures performed, 31 (43.1%) lesions were classified as Trans-Atlantic Inter-Society Consensus Document II D. There were 66 (75%) endovascular procedures, 16 (18.2%) open surgery, and 6 (6.8%) hybrid interventions. No statistically significant relationship was found between the calcium score of the segments (aorta, iliac, femoropopliteal, infrapopliteal, the operated limb, and total calcium score) and the outcomes of acute myocardial infarction, amputation, patency, and technical success in any of the periods analyzed. The calcium score of the operated limb was higher in patients who died within 30 days and 6 months (6571 vs 2590.6; p=0.026) and (5227.8 vs 2335.3; p=0.036).

CONCLUSION

A standardized calcium score calculation method with the angiographic phase of the computed tomography is feasible and reproducible. Higher values of the calcifications of the operated limb are related to a greater chance of death in the postoperative period. The calcium score of the operated limb can be considered as a marker of clinical severity and prognosis in this group of patients.

Pedal arterial calcification score is associated with the risk of major amputation in chronic limb-threatening ischemia

OBJECTIVE

The medial arterial calcification (MAC) score is a simple metric that describes the burden of inframalleolar calcification using a plain foot radiograph. We hypothesized that a higher MAC score would be independently associated with the risk of major amputation in patients with chronic limb-threatening ischemia (CLTI).

METHODS

We performed a single-institution, retrospective study of 250 patients who had undergone infrainguinal revascularization for CLTI from January 2011 to July 2019 and had foot radiographs available for MAC score calculation. A single blinded reviewer assigned MAC scores of 0 to 5 using two-view minimum plain foot radiographs, with 1 point each for calcification of >2 cm in the dorsalis pedis, plantar, and metatarsal arteries and >1 cm in the hallux and non-hallux digital arteries.

RESULTS

The MAC score was 0 in 36%, 1 in 5.2%, 2 in 8.4%, 3 in 14%, 4 in 14%, and 5 in 21%. The MAC score was trichotomized to facilitate analysis and clinical utility (mild, MAC score 0-1; moderate, MAC score 2-4; and severe, MAC score 5). The variables independently associated with a higher MAC score were male sex, diabetes, end-stage renal disease, and the global limb anatomic staging system pedal score. The MAC score was not associated with the Society for Vascular Surgery WIfI (wound, ischemia, foot infection) grade or overall WIfI stage (P = .58). The median follow-up was 759 days (interquartile range, 264-1541 days). A higher MAC score was significantly associated with the risk of major amputation (P < .0001). In a Cox proportional hazards multiple regression model for major amputation that included the trichotomized MAC score, diabetes, end-stage renal disease, and WIfI stage (1-3 vs 4). The MAC score (MAC score 5: hazard ratio [HR], 4.9; 95% confidence interval [CI], 1.9-13.1; P = .001; MAC score 2-4: HR, 3.4; 95% CI, 1.3-8.8; P = .01) and WIfI stage (WIfI stage 4: HR, 2.1; 95% CI, 1.1-3.9; P = .03) were significantly associated with the risk of major amputation. In the subsets of patients with the most advanced WIfI stage of 3 to 4 (191 of 250; 76%) and patients with diabetes (185 of 250; 74%), the MAC score further stratified the risk of major amputation on univariate and multivariate analyses.

CONCLUSIONS

The MAC score is a simple, practical tool and a strong independent predictor of major amputation in patients with CLTI. It provides novel clinical data that are currently unmeasured using any validated CLTI staging system. The MAC score is a promising standardized measure of inframalleolar disease burden that can be used in conjunction with the WIfI staging system to help improve outcomes stratification and determine the optimal treatment strategies for patients with CLTI.

Hand osteomyelitis in arterial calcification, diabetes mellitus and end-stage renal failure: a comparison of 210 cases over 12 years

We present 210 patients with hand osteomyelitis in 246 rays over 12 years, including detailed analysis of 29 patients in this cohort with digital artery calcification evident on plain X-ray. Overall 71 patients had diabetes mellitus and/or end-stage renal failure, including 28 of 29 patients with calcification. In the calcification group, 17 patients had ipsilateral arteriovenous fistulae, five had steal syndrome and 15 had digital ulceration or skin necrosis. Compared with 181 controls, patients with calcification had more affected bones, polymicrobial infections, surgical procedures, phalanges and digits amputated and had higher mortality at 1 year (12 of 29) and 5 years (20 of 29), as a result of comorbidities. Absence of calcification in 43 patients with diabetes and/or end-stage renal failure was associated with better outcomes on all the above parameters. Early amputation to maximize disease-free survival may be appropriate for patients with hand osteomyelitis and arterial calcification.Level of evidence: IV.

The Global Limb Anatomic Staging System (GLASS) for CLTI: Improving Inter-Observer Agreement

Objective: The 2020 Global Vascular Guidelines aim at improving decision making in Chronic Limb-Threatening Ischemia (CLTI) by providing a framework for evidence-based revascularization. Herein, the Global Limb Anatomic Staging System (GLASS) serves to estimate the chance of success and patency of arterial pathway revascularization based on the extent and distribution of the atherosclerotic lesions. We report the preliminary feasibility results and observer variability of the GLASS. GLASS is a part of the new global guideline and posed as a promising additional tool for EBR strategies to predict the success of lower extremity arterial revascularization. This study reports on the consistency of GLASS scoring to maximize inter-observer agreement and facilitate its application. Methods: GLASS separately scores the femoropopliteal (FP) and infrapopliteal (IP) segment based on stenosis severity, lesion length and the extent of calcification within the target artery pathway (TAP). In our stepwise approach, we used two angiographic datasets. Each following step was based on the lessons learned from the previous step. The primary outcome was inter-observer agreement measured as Cohen’s Kappa, scored by two (step 1 + 2) and four (step 3) blinded and experienced observers, respectively. Steps 1 (n = 139) and 2 (n = 50) were executed within a dataset of a Dutch interventional RCT in CLTI. Step 3 (n = 100) was performed in randomly selected all-comer CLTI patients from two vascular centers in the United States. Results: In step 1, kappa values were 0.346 (FP) and 0.180 (IP). In step 2, applied in the same dataset, the use of other experienced observers and a provided TAP, resulted in similar low kappa values 0.406 (FP) and 0.089 (IP). Subsequently, in step 3, the formation of an altered stepwise approach using component scoring, such as separate scoring of calcification and adding a ruler to the images resulted in kappa values increasing to 0.796 (FP) and 0.730 (IP). Conclusion: This retrospective GLASS validation study revealed low inter-observer agreement for unconditioned scoring. A stepwise component scoring provides acceptable agreement and a solid base for further prospective validation studies to investigate how GLASS relates to treatment outcomes.

Calcification patterns in femoral and carotid atheromatous plaques: A comparative morphometric study

This comparative study was designed to focus on the mineral patterns in human atherosclerotic plaques based on quantitative measurements of calcium deposits through the morphometric method. A total of 101 atherosclerotic plaques were harvested by conventional transluminal angioplasty from the carotid artery (CA) and different segments of the femoral-popliteal axis (FPA), fixed in formalin and sent for histological processing. The histological grade of the atherosclerotic plaque and the calcification pattern were evaluated, followed by a morphometric analysis of the mineral deposits. Regarding the localization, the advanced plaques (VII and VIII types) developed predominantly at the level of the superficial femoral artery (SFA) compared to the CA (P<0.001). This significant difference was maintained even if they were divided into low grade (IV and V) and high grade categories (VI, VII and VIII) (P<0.05). Compared with that in the carotid plaques, in the FPA plaques the mineralized surface increased in parallel with the narrowing of the vascular lumen diameter. The image analysis of the total pathological calcification score (pCS) showed a significant difference between the CA plaques and distal SFA (dSFA) plaques (P=0.038) and between the proximal SFA (pSFA) and dSFA plaques (P=0.013). In the case of the simple nodular pattern, calcification occupied significantly larger areas in the plaques developed in the dSFA and popliteal artery (PA) in comparison with the CA plaques (P=0.0007 and P=0.0009). pCSs calculated in plaques with extensive calcification pattern showed a lower value in the CA vs. the pSFA plaques (P=0.004). A less pronounced, but significant difference was observed between the pCS of pSFA and dSFA plaques (P=0.017). Femoral and carotid plaques exhibited different morphology and tendency for calcification. In parallel with the narrowing of the vascular lumen diameter, the mineralized surface increased at the level of different FPA segments. These results suggest that the mechanism is site-specific, and wall structure-dependent.

Recovery of limb perfusion and function after hindlimb ischemia is impaired by arterial calcification

Medial artery calcification results from deposition of calcium hydroxyapatite crystals on elastin layers, and osteogenic changes in vascular smooth muscle cells. It is highly prevalent in patients with chronic kidney disease, diabetes, and peripheral artery disease (PAD), and when identified in lower extremity vessels, it is associated with increased amputation rates. This study aims to evaluate the effects of medial calcification on perfusion and functional recovery after hindlimb ischemia in rats. Medial artery calcification and acute limb ischemia were induced by vitamin D3 (VitD3 ) injection and femoral artery ligation in rats. VitD3 injection robustly induced calcification in the medial layer of femoral arteries in vivo. Laser Doppler perfusion imaging revealed that perfusion decreased and then partially recovered after hindlimb ischemia in vehicle-injected rats. In contrast, VitD3 -injected rats showed markedly impaired recovery of perfusion following limb ischemia. Accordingly, rats with medial calcification showed worse ischemia scores and delayed functional recovery compared with controls. Immunohistochemical and histological staining did not show differences in capillary density or muscle morphology between VitD3 - and vehicle-injected rats at 28 days after femoral artery ligation. The evaluation of cardiac and hemodynamic parameters showed that arterial stiffness was increased while cardiac function was preserved in VitD3 -injected rats. These findings suggest that medial calcification may contribute to impaired perfusion in PAD by altering vascular compliance, however, the specific mechanisms remain poorly understood. Reducing or slowing the progression of arterial calcification in patients with PAD may improve clinical outcomes.

Advances in Revascularization for Peripheral Artery Disease: Revascularization in PAD

Effective revascularization of the patient with peripheral artery disease is about more than the procedure. The approach to the patient with symptom-limiting intermittent claudication or limb-threatening ischemia begins with understanding the population at risk and variation in clinical presentation. The urgency of revascularization varies significantly by presentation; from patients with intermittent claudication who should undergo structured exercise rehabilitation before revascularization (if needed) to those with acute limb ischemia, a medical emergency, who require revascularization within hours. Recent years have seen the rapid development of new tools including wires, catheters, drug-eluting technology, specialized balloons, and biomimetic stents. Open surgical bypass remains an important option for those with advanced disease. The strategy and techniques employed vary by clinical presentation, lesion location, and lesion severity. There is limited level 1 evidence to guide practice, but factors that determine technical success and anatomic durability are largely understood and incorporated into decision-making. Following revascularization, medical therapy to reduce adverse limb outcomes and a surveillance plan should be put in place. There are many hurdles to overcome to improve the efficacy of lower extremity revascularization, such as restenosis, calcification, microvascular disease, silent embolization, and tools for perfusion assessment. This review highlights the current state of revascularization in peripheral artery disease with an eye toward technologies at the cusp, which may significantly impact current practice.

Evaluating the Impact of Medial Arterial Calcification on Outcomes of Infrageniculate Endovascular Interventions for Treatment of Diabetic Foot Ulcers

BACKGROUND

Medial arterial calcification (MAC) of the tibial and pedal arteries has been associated with an increased risk of amputation among people with diabetes. Endovascular interventions on infrageniculate vessels are frequently performed with the intent of treating peripheral artery disease (PAD) and decreasing the risk of amputation in those with diabetes. This study aimed to investigate how the extent of MAC impacts outcomes of endovascular procedures in people with diabetic foot ulcers (DFU).

METHODS

We identified all patients who had undergone infrageniculate angioplasty in the setting of DFU at our institution between 2009 and 2019. Subjects were assigned a MAC score based on the severity of MAC in each vessel visualized on plain radiographs of the ankle and foot. We evaluated the relationship between MAC and the primary outcome, major adverse limb event (MALE), using stratified Cox proportional modeling.

RESULTS

Among 99 subjects with DFU who had undergone infrageniculate angioplasty, MALE occurred in 50% (95% confidence interval [CI] 38%-61%) of patients within 1 year of intervention. On univariate Cox regression analysis, each 1 point increment in MAC score (hazard ratio [HR], 1.09; 95% CI 1.01-1.18), the third tertile of MAC score (HR, 2.27; 95% CI 1.01-5.11), age (HR 0.96; 95% CI 0.93-0.99), and wound grade (HR, 5.34; 95% CI 2.17-13.14), were significantly associated with increased risk of MALE. On adjusted analysis stratified by wound grade, MAC score was found to be associated with MALE only in patients with a low wound grade.

CONCLUSION

Increased severity of MAC is associated with increased risk of MALE for subjects undergoing infrageniculate angioplasty with a low wound grade. Further research is needed to better understand the complex relationships of MAC, PAD, DFU, and interventions aimed at promoting healing of DFU.

Association of infrapopliteal medial arterial calcification with lower-limb amputations in high-risk patients: A systematic review and meta-analysis

Medial arterial calcification (MAC) is a known risk factor for cardiovascular morbidity. The association between vascular calcifications and poor outcome in several vascular districts suggest that infrapopliteal MAC could be a risk factor for lower-limb amputation (LLA). This study's objective is to review the available literature focusing on the association between infrapopliteal MAC and LLA in high-risk patients. The PubMed and Embase databases were systematically searched. We selected original studies reporting the association between infrapopliteal MAC and LLAs in patients with diabetes and/or peripheral artery disease (PAD). Estimates were pooled using either a fixed-effects or a random-effects model meta-analysis. Heterogeneity was evaluated using the Q and I² statistics. Publication bias was investigated with a funnel plot and Egger test. The trim-and-fill method was designed to estimate the possibly missing studies. Influence analysis was conducted to search studies influencing the final result. Test of moderators was used to compare estimates in good versus non-good-quality studies. Fifteen articles satisfied the selection criteria (n = 6489; median follow-up: 36 months). MAC was significantly associated with LLAs (pooled adjusted risk ratio (RR): 2.27; 95% CI: 1.89-2.74; I² = 25.3%, Q-test: p = 0.17). This association was kept in the subgroup of patients with diabetes (RR: 2.37; 95% CI: 1.76-3.20) and patients with PAD (RR: 2.48; 95% CI: 1.72-3.58). The association was maintained if considering as outcome only major amputations (RR: 2.11; 95% CI: 1.46-3.06). Our results show that infrapopliteal MAC is associated with LLAs, thus suggesting MAC as a possible new marker of the at-risk limb.

Atherectomy with balloon angioplasty compared to balloon angioplasty alone for the treatment of chronic limb threatening ischemia: A national surgical quality improvement program database analysis

OBJECTIVES

To compare perioperative outcomes related to atherectomy with percutaneous transluminal angioplasty versus percutaneous transluminal angioplasty alone for the treatment of lower extremity chronic limb threatening ischemia using a national patient database.

METHODS

Patients with chronic limb threatening ischemia treated with atherectomy and percutaneous transluminal angioplasty or percutaneous transluminal angioplasty alone from 2011 to 2016 in the National Surgical Quality Improvement Program database were identified. Primary outcomes were major adverse limb events (30-day untreated loss of patency, major reintervention, major amputation) and major adverse cardiac events (cardiac arrest, composite outcome of myocardial infarction or stroke). Secondary outcomes included 30-day mortality, length of stay, and any unplanned readmission within 30 days. Multivariate regression analyses were performed to determine independent predictors of outcome. Propensity score matched cohort analysis was performed. A p-value <0.05 was considered statistically significant. Subgroup analyses of femoropopliteal and infrapopliteal interventions were performed.

RESULTS

In total, 2636 (77.2%) patients were treated with percutaneous transluminal angioplasty and 778 (22.8%) were treated with atherectomy and percutaneous transluminal angioplasty. Multivariate analyses of the unadjusted cohort revealed no significant differences in major adverse cardiac events or major adverse limb events between the two groups (p-value >0.05). Subgroup analysis of femoropopliteal interventions demonstrated a significantly decreased likelihood of untreated loss of patency in 30 days in the atherectomy group compared to the percutaneous transluminal angioplasty group (1.1% vs. 2.7%, respectively; p-value = 0.034), which persisted on propensity score matched analysis (1.1% vs. 3.1%, respectively; p-value = 0.026).

CONCLUSION

Atherectomy with balloon angioplasty of femoropopliteal disease provides a significant decrease in untreated loss of patency compared to balloon angioplasty alone.

Circulating Receptor Activator of Nuclear Factor kB Ligand and triglycerides are associated with progression of lower limb arterial calcification in type 2 diabetes: a prospective, observational cohort study

Background

Lower limb arterial calcification is a frequent, underestimated but serious complication of diabetes. The DIACART study is a prospective cohort study designed to evaluate the determinants of the progression of lower limb arterial calcification in 198 patients with type 2 diabetes.

Methods

Lower limb arterial calcification scores were determined by computed tomography at baseline and after a mean follow up of 31.20 ± 3.86 months. Serum RANKL (Receptor Activator of Nuclear factor kB Ligand) and bone remodeling, inflammatory and metabolic parameters were measured at baseline. The predictive effect of these markers on calcification progression was analyzed by a multivariate linear regression model.

Results

At baseline, mean ± SD and median lower limb arterial calcification scores were, 2364 ± 5613 and 527 respectively and at the end of the study, 3739 ± 6886 and 1355 respectively. Using multivariate analysis, the progression of lower limb arterial log calcification score was found to be associated with (β coefficient [slope], 95% CI, p-value) baseline log(calcification score) (1.02, 1.00–1.04, p < 0.001), triglycerides (0.11, 0.03–0.20, p = 0.007), log(RANKL) (0.07, 0.02–0.11, p = 0.016), previous ischemic cardiomyopathy (0.36, 0.15–0.57, p = 0.001), statin use (0.39, 0.06–0.72, p = 0.023) and duration of follow up (0.04, 0.01–0.06, p = 0.004).

Conclusion

In patients with type 2 diabetes, lower limb arterial calcification is frequent and can progress rapidly. Circulating RANKL and triglycerides are independently associated with this progression. These results open new therapeutic perspectives in peripheral diabetic calcifying arteriopathy.

Trial registration NCT02431234

The risk factors for calcification vary among the different sections of the lower extremity artery in patients with symptomatic peripheral arterial disease

BACKGROUND

Peripheral arterial disease (PAD) is associated with considerable mortality and morbidity worldwide. The present study explored the risk factors for arterial calcification among the different sections of the lower extremity in patients with PAD and analyzed their correlations with the extent of arterial stenosis at the corresponding section.

METHODS

This study enrolled symptomatic PAD patients from our hospital from March 2017 to March 2018. The lower extremity arterial calcification score (LEACS) and lower extremity arterial stenosis index (LEASI), representing the extent of arterial stenosis, were measured on computed tomography (CT) and the correlations between them were analyzed using Spearman's correlation analysis. The relationships between risk factors and calcification were analyzed among the different sections of the lower extremity artery.

RESULTS

In total, 209 patients were included. The LEACSs of the total lower extremity, aortoiliac artery, and femoropopliteal and infrapopliteal arteries were correlated with the LEASI (all P < 0.05), but their correlation was relatively weak in the aortoiliac artery. Univariate analysis showed that hypertension was associated with the total (P = 0.019) and aortoiliac (P = 0.012) LEACSs. Diabetes was related to both femoropopliteal (P = 0.001) and infrapopliteal (P = 0.002) LEACSs. The infrapopliteal LEACS was higher in male patients (P = 0.011). After adjustment for age, the above relationships were maintained among the different sections, but not in the total lower extremity artery.

CONCLUSIONS

The LEACS is associated with the LEASI in all arterial sections, but that of the aortoiliac artery was relatively weak. Different factors have different effects on calcification among the various sections of the lower extremity artery.

Balloon Angioplasty of Infrapopliteal Arteries: A Systematic Review and Proposed Algorithm for Optimal Endovascular Therapy

Endovascular revascularization has been increasingly utilized to treat patients with chronic limb-threatening ischemia (CLTI), particularly atherosclerotic disease in the infrapopliteal arteries. Lesions of the infrapopliteal arteries are the result of 2 different etiologies: medial calcification and intimal atheromatous plaque. Although several devices are available for endovascular treatment of infrapopliteal lesions, balloon angioplasty still comprises the mainstay of therapy due to a lack of purpose-built devices. The mechanism of balloon angioplasty consists of adventitial stretching, medial necrosis, and dissection or plaque fracture. In many cases, the diffuse nature of infrapopliteal disease and plaque complexity may lead to dissection, recoil, and early restenosis. Optimal balloon angioplasty requires careful attention to assessment of vessel calcification, appropriate vessel sizing, and the use of long balloons with prolonged inflation times, as outlined in a treatment algorithm based on this systematic review. Further development of specific devices for this arterial segment are warranted, including devices for preventing recoil (eg, dedicated atherectomy devices), treating dissections (eg, tacks, stents), and preventing neointimal hyperplasia (eg, novel drug delivery techniques and drug-eluting stents). Further understanding of infrapopliteal disease, along with the development of new technologies, will help optimize the durability of endovascular interventions and ultimately improve the limb-related outcomes of patients with CLTI.

Infrapopliteal Anatomic Severity and Delayed Wound Healing in Patients With Chronic Limb-Threatening Ischemia in the Era of the Global Limb Anatomic Staging System

Purpose: To investigate the prognostic impact of infrapopliteal (IP) artery anatomic severity according to the Global Limb Anatomic Staging System (GLASS) on delayed wound healing in patients with chronic limb-threatening ischemia (CLTI). Materials and Methods: This study retrospectively analyzed 639 limbs with tissue loss in 484 CLTI patients (mean age 74±10 years; 300 men) presenting IP lesions treated with endovascular therapy between April 2010 and December 2015. Two-thirds of patients had diabetes (323, 67%) and over half were on hemodialysis (255, 53%). More than a third of the limbs (251, 39%) were classified as clinical stage 4 according to the Wound, Ischemia, and foot Infection (WIfI) system. IP anatomic severity was classified based on preprocedural angiography according to the GLASS. Severity of arterial calcification was assessed using high-intensity fluoroscopy and classified into 3 groups: none (grade 0), unilateral (grade 1), and bilateral (grade 2). Poor below-the-ankle (BTA) runoff was defined as the lack of a pedal arch with 0 to 1-vessel runoff within the dorsal pedis artery and the lateral and medial plantar arteries. The outcome measure was 1-year wound healing. The association of anatomic characteristics with delayed wound healing was evaluated using Cox proportional hazards regression analysis. Outcomes are presented as the adjusted hazard ratio (HR) with 95% confidence interval (CI). Results: During a mean follow-up of 22±19 months, the 1-year cumulative wound healing rate was estimated to be 59.0% (95% CI 54.5% to 63.5%). Multivariable analysis demonstrated independent associations between delayed wound healing and IP calcification grade (HR 1.24, 95% CI 1.02 to 1.50, p=0.027) and poor BTA runoff (HR 1.39, 95% CI 1.04 to 1.85, p=0.025) but not the GLASS IP grade (HR 0.92, 95% CI 0.82 to 1.14, p=0.21). Conclusion: The current study revealed that IP arterial calcification and poor BTA runoff were significantly associated with delayed wound healing, whereas the GLASS was not predictive of wound healing.

Oral Anticoagulants and Antiplatelet Agents in Patients With Atrial Fibrillation and Concomitant Critical Limb Ischemia: A Nationwide Cohort Study

BACKGROUND

Evidence of clinical outcomes for oral anticoagulants and antiplatelet treatment (APT) in patients with atrial fibrillation (AF) and critical limb ischemia (CLI) is very limited.

METHODS

In this nationwide retrospective cohort study collected from Taiwan National Health Insurance Research Database, 1223 patients with AF and CLI taking direct-acting oral coagulants (DOACs), warfarin, or APT were identified from June 1, 2012, to December 31, 2017. We used propensity score stabilized weighting (PSSW) to balance covariates across study groups.

RESULTS

After PSSW, DOAC (n = 446) was associated with lower risks of ischemic stroke/systemic embolism (IS/SE), all major adverse limb events, and all major bleeding events compared with warfarin (n = 237). DOAC was associated with lower risks of IS/SE, acute myocardial infarction (AMI), and all major adverse limb events and a comparable risk of major bleeding events compared with APT (n = 540). DOAC has a lower risk of composite net-clinical-benefit outcome (IS/SE, AMI, all major adverse limb events, plus all major bleeding events) compared with warfarin (hazard ratio [HR]: 0.48; 95% confidence interval [CI]: 0.35-0.65; P < 0.0001) or APT (HR: 0.44; 95% CI: 0.34-0.56; P < 0.0001). The composite net-clinical-benefit outcome was comparable for warfarin vs APT. The reduced risk of net-clinical-benefit outcome for DOAC vs warfarin or APT persisted in high subgroups including age > 75 years, presence of diabetes mellitus, or chronic kidney disease.

CONCLUSIONS

DOAC was associated with a significantly lower risk of composite net-clinical-benefit outcome than either warfarin or APT in patients with AF and concomitant CLI. Further prospective study is necessary to validate the findings in the future.

Effectiveness, safety, and major adverse limb events in atrial fibrillation patients with concomitant diabetes mellitus treated with non-vitamin K antagonist oral anticoagulants

BACKGROUND

Evidence of adverse clinical outcomes for non-vitamin K antagonist oral anticoagulant (NOACs) and warfarin in patients with atrial fibrillation (AF) and diabetes mellitus are limited. We investigated the effectiveness, safety, and major adverse limb events for NOACs versus warfarin among diabetic AF patients.

METHODS

In this nationwide retrospective cohort study collected from Taiwan National Health Insurance Research Database, we identified a total of 20,967 and 5812 consecutive AF patients with diabetes taking NOACs and warfarin from June 1, 2012, to December 31, 2017, respectively. We used propensity-score stabilized weighting to balance covariates across study groups.

RESULTS

NOAC was associated with a lower risk of major adverse cardiovascular events (MACE) (adjusted hazard ratio (aHR):0.88; [95% confidential interval (CI) 0.78-0.99]; P = 0.0283), major adverse limb events (MALE) (aHR:0.72;[95% CI 0.57-0.92]; P = 0.0083), and major bleeding (aHR:0.67;[95% CI 0.59-0.76]; P < 0.0001) compared to warfarin. NOACs decreased MACE in patients of ≥ 75 but not in those aged < 75 years (P interaction = 0.01), and in patients with ischemic heart disease (IHD) compared to those without IHD (P interaction < 0.01). For major adverse limb events, the advantage of risk reduction for NOAC over warfarin persisted in high risk subgroups including age ≥ 75 years, chronic kidney disease, IHD, peripheral artery disease, or use of concomitant antiplatelet drugs.

CONCLUSION

Among diabetic AF patients, NOACs were associated with a lower risk of thromboembolism, major bleeding, and major adverse limb events than warfarin. Thromboprophylaxis with NOACs should be considered in the diabetic AF population with a high atherosclerotic burden.

Warfarin Accelerates Medial Arterial Calcification in Humans

Objective:

Warfarin is associated with medial arterial calcification in humans, but the magnitude and specificity of this effect and the role of other risk factors are unknown. Using serial mammograms, progression of arterial calcification was compared in women receiving no anticoagulants, warfarin, or other anticoagulants, and before, during, and after warfarin use.

Approach and Results:

Warfarin users with mammograms were identified by computerized searches of medical records that included renal function and diabetes mellitus. Lengths of calcified arterial segments were measured, with progression expressed as millimeters per breast per year and presented as medians and interquartile range (IQR). In women with normal renal function (estimated glomerular filtration rate >60 mL/minute per 1.73 m 2 ), progression was 3.9-fold greater in warfarin users: 9.9 (3.8–16) versus 2.5 (0.7–6.7) in controls, P =0.0003, but not increased in users of other anticoagulants. In longitudinal analyses, progression increased from 2.1 (IQR, 0.3–3.9) to 13.8 (IQR, 7.8–38.7; P =0.011) after starting warfarin (n=11) and decreased from 8.8 (IQR, 1.1–10) to 1.9 (IQR, −10 to 6.7; P =0.024) after discontinuation of warfarin (n=13). Progression of calcification was similar in warfarin users with chronic kidney disease (7.3 [IQR, 3.6–17], n=29) but markedly accelerated in warfarin users with end-stage renal disease (47 [IQR, 31–183], n=11; P =0.0002). Progression was similar in diabetic and nondiabetic warfarin users (10.1 [IQR, 3.8–24] versus 7.8 [IQR, 3.6–15]) and did not correlate with age ( r =0.09) or duration of warfarin therapy ( r =0.12).

Conclusions:

Warfarin significantly accelerates medial arterial calcification in humans. This effect is markedly augmented in end-stage renal disease.

Percutaneous Impella Mechanical Circulatory Support Delivery Using Intravascular Lithotripsy

Intravascular lithotripsy (IVL) may be useful to deliver Impella devices in patients with peripheral arterial disease. Twelve patients were treated with peripheral IVL prior to Impella insertion. A total of 100% of patients underwent successful device implantation with no IVL complications. IVL can facilitate transfemoral access for Impella insertion. (Level of Difficulty: Advanced.).

Diagnostic Tests for Vascular Calcification

Vascular calcification (VC) is the heterogeneous endpoint of multiple vascular insults, which varies by arterial bed, the layer of the arterial wall affected, and is propagated by diverse cellular and biochemical mechanisms. A variety of in vivo and ex vivo techniques have been applied to the analysis of VC in preclinical studies, but clinical examination has principally relied on a number of noninvasive and invasive imaging modalities for detection and quantitation. Most imaging methods suffer from suboptimal spatial resolution, leading to the inability to distinguish medial from intimal VC and insufficient sensitivity to detect microcalcifications that are indicative of active mineral deposition and of vulnerable plaques which may be prone to rupture. Serum biomarkers lack specificity for VC and cannot discriminate pathology. Overall, uncertainties surrounding the sensitivity and specificity of different VC testing modalities, the absence of a clear cause-effect relationship, and lack of any evidence-based diagnostic or therapeutic protocols in relation to VC testing in chronic kidney disease has yielded weak or ungraded recommendations for their use in clinical practice. While VC is recognized as a key manifestation of chronic kidney disease-mineral and bone disorder and those with an increasing burden of VC are considered to be at higher cardiovascular risk, routine screening is not currently recommended.