Association of arterial calcification with chronic limb ischemia in patients with peripheral artery disease

Metabolic dysfunction-associated steatotic liver disease (MASLD) biomarkers and progression of lower limb arterial calcification in patients with type 2 diabetes: a prospective cohort study

BACKGROUND

Studies have demonstrated that both lower limb arterial calcification and metabolic dysfunction-associated steatotic liver disease (MASLD) are linked to the development of peripheral artery disease. However, the potential relationship between MASLD biomarkers and progression of lower limb arterial calcification in individuals with type 2 diabetes (T2D) remains unclear. This study aimed to investigate whether the biomarkers of MASLD included in the FibroMax® panels are associated with the progression of lower limb arterial calcification in patients with T2D.

METHODS

The lower limb arterial calcification score (LLACS) was evaluated through computed tomography at baseline and after an average follow-up of 31.2 ± 3.7 months in a cohort of 150 patients with T2D. We also measured the serum biomarkers included in the FibroMax® panels (SteatoTest®, FibroTest®, NashTest®, ActiTest®). The predictive ability of these biomarkers of MASLD on LLACS progression was assessed through univariate and multivariate linear regression models, principal component regression analysis, as well as machine learning algorithms.

RESULTS

During the follow-up period, LLACS increased in 127 (85%) of the 150 patients with T2D. In univariate analysis, the annualized change in LLACS was positively and mainly correlated with baseline LLACS (r = 0.860, p < 0.0001), the FibroTest® score (r = 0.304, p = 0.0002), and age (r = 0.275, p = 0.0006), and negatively correlated with glomerular filtration rate (r = - 0.242, p = 0.003). In multivariate analysis, the FibroTest® score remained independently associated with the annualized change in LLACS, after adjusting for baseline LLACS and risk factors for lower extremity artery disease (β coefficient [95% confidence interval]: 988 [284-1692], p = 0.006). This association persisted even after adjustment for variables selected by principal component analysis (β = 1029 [289-1768], p = 0.007). Two advanced machine learning models identified the FibroTest® score as the second most important predictor of annualized change in LLACS, following baseline LLACS.

CONCLUSIONS

This study represents the first demonstration of an independent relationship between a non-invasive liver fibrosis test and the progression of lower limb arterial calcification in patients with T2D. Beyond its utility in assessing liver fibrosis, the FibroTest® could be a valuable and easy-to-use biomarker for predicting the risk of worsening lower limb arterial calcification.

TRIAL REGISTRATION

ClinicalTrials.gov identifier NCT02431234.

Predictive value of tibial and coronary artery calcification scores for cardiac and lower extremity events

OBJECTIVE

The extent of calcification in tibial and coronary arteries predicts major ischemic events. Tibial calcification predicts ischemic events in a manner independent of the degree of associated atherosclerotic occlusive disease while coronary calcification can improve risk stratification in patients at intermediate risk for cardiovascular disease. We thus assessed the relationship between tibial and coronary calcification, the influence of cardiovascular risk factors on their extent, and their individual predictive value on major adverse limb and cardiac events (MALE and MACE).

METHODS

We retrospectively reviewed images and collected demographic and cardiovascular risk factor data of patients who underwent CT scans of the lower extremities and chest. Calcification in the tibial and coronary arteries were identified and scored using a semi-automated method. A spearman correlation coefficient was calculated using tibial and coronary artery calcification scores (TAC and CAC). Ordinal logistic regression and multiple linear regression were performed using cardiovascular and demographic factors as covariates. Log-rank test and Kaplan-Meier estimate were completed to assess MACE and MALE free probability.

RESULTS

A total of 101 patients were identified who met inclusion criteria. There was a strong correlation (r=0.76) between CAC and TAC scores. Severe CAC (defined as > 400) and severe TAC (defined as > 500) scores were both associated with advanced age, male sex, a history of smoking, and diabetes. Renal disease was associated with a high TAC score but not CAC. An increasing TAC score was associated with increased MACE (p<0.0001) and MALE (p=0.039). However, increasing CAC was only associated with increased MACE (p=0.0036).

CONCLUSION

We provide data suggesting that TAC and CAC share similar risk factors and are highly correlated. Interestingly, TAC predicts both MACE and MALE, while CAC is best at predicting coronary, but not lower extremity events. Further studies are needed to understand the contributions of arterial calcification to myocardial and lower extremity ischemia.

Aortic calcium score predicts early outcomes in aortoiliac revascularization

BACKGROUND

Calcium scores were evaluated in the lower limbs of patients with clinical limb ischemia after aortoiliac revascularization. The aortic calcium score was related to the short-term outcomes of amputation and subsequent revascularization. Similarly, the calcium score in below-the-knee arteries was associated with revascularization and amputation at 12 months. ■ The calcium score can be calculated using computed tomography angiography. ■ The aortic calcium score was associated with amputation and subsequent revascularization within 30 days. ■ The calcium score in below-the-knee arteries was higher in the patients who underwent subsequent revascularization and amputation at 12 months.

OBJECTIVE

To evaluate the association between lower limb artery calcium scores in preoperative computed tomography angiography and outcomes of patients with critical limb ischemia who underwent revascularization procedures in the aortoiliac segment.

METHODS

We retrospectively reviewed 14 interventions performed on 11 patients. The calcium score was calculated in segments of the aorta, iliac, femoropopliteal, and below-the-knee arteries. The evaluated outcomes included amputation, patency, death, subsequent revascularization, and readmission. Major adverse limb events were defined as amputation, subsequent revascularization, or readmission. The patients were followed through a 12-month period.

RESULTS

Higher aortic calcium scores were associated with amputation within 30 days (5,767.6 versus 805.3; p=0.02). Amputation during the first year correlated with a higher below-the-knee arteries calcium score (672.4 versus 163.25; p=0.04). Subsequent revascularization within 30 days was associated with a higher aortic calcium score (3,686.8 versus 645.2; p=0.008), while below-the-knee arteries calcium scores were associated with revascularization within 30 days (155.5 versus 817; p=0.05) and 12 months (158.875 versus 679.4; p=0.019). Readmissions within 1 year were more prevalent with higher below-the-knee arteries calcium scores (882.4 versus 32; p=0.011). Major adverse limb events were related to below-the-knee arteries calcium scores at 30 days (158.875 versus 679.4; p=0.019) and 1 year (12.3 versus 910.1; p=0.002).

CONCLUSION

Below-the-knee arteries calcium score is a predictor of long-term revascularization, amputation, readmission, and major adverse limb events. The aortic calcium score was associated with amputation and subsequent revascularization within the first 30 days.

Association of Iliofemoral Calcium Score and Major Vascular Complications within the First Year after Lower Limb Endovascular Revascularization

BACKGROUND

The accumulation of calcium load in peripheral lower extremity arteries has been associated with increased severity of peripheral artery disease (PAD) and mortality. While calcium scores are commonly calculated from non-contrast computed tomography (CT) scans, patients with PAD often undergo contrast-enhanced CT scans. This study aims to explore the association between a length-adjusted calcium score (LACS) of the iliofemoral arteries, determined through pre-intervention contrast-enhanced CT, and major adverse events in patients with chronic limb-threatening ischemia (CLTI).

METHODS

A cohort of CLTI patients subjected to endovascular revascularization between 2005 and 2017 at a tertiary referral center were categorized into 2 groups. The complication group experienced one of the composite outcomes (reintervention, above-the-ankle amputation, and/or all-cause mortality within 1 year of the primary endovascular procedure), while control patients did not encounter this composite endpoint. Patients from the complication group were matched one-to-one with controls based on sex and Fontaine classification. LACS was calculated (Ca volume[mm3]/length[cm]) at 3 arterial segments; 1. the common iliac artery (CIA), 2. the external iliac artery and common femoral artery (EIA + CFA), and 3. the superficial femoral artery plus the popliteal artery (SFA + PA). Binary logistic regression analysis was conducted to investigate the association between LACS in the different arterial segments and the occurrence of the composite binary outcome (complication and control) and LACS of the different segments, adjusting influences of age, sex, BMI >25, Fontaine classification, diabetes mellitus type 1 & 2, chronic kidney disease stage, and hemodialysis treatment.

RESULTS

Sixty-four CLTI patients were included in this study (complication group [n = 32], and control group [n = 32]). A significant difference (higher LACS was found for the complication group in the CIA, the SFA + PA, as well as the total trajectory. CLTI patients with high LACS in the SFA + PA or the total trajectory were more likely to suffer adverse events (SFA + PA: OR: 1.010, 95% CI: 1.000-1.020, P = 0.04; Total LACS: OR: 1.008, 95% CI: 1.000-1.017, P = 0.05).

CONCLUSIONS

Patients with a high calcium load in the ilio-femoral arteries are at increased risk of major adverse events during 1 year after endovascular revascularization. The calcium score, derived from contrast-enhanced CT scans, holds potential utility in decision making for CLTI patients.

Predictive Ability of the Pedal Medial Arterial Calcification Score for Major Adverse Limb Events Among Patients with Chronic Limb-Threatening Ischemia

BACKGROUND

Pedal medial arterial calcification (pMAC) is a potential predictor of major adverse limb events (MALEs) among patients with critical limb-threatening ischemia (CLTI). This study aims to validate the prognostic value of the pMAC score in predicting major lower-limb amputation (MLLA) and need for redo revascularisation.

METHODS

A single-center study involving 196 patients diagnosed with CLTI, reviewed between 2012 and 2022. Patients' pMAC scores were obtained through X-ray assessments. Correlations between pMAC scores and the incidence of MALE and redo revascularization, were analyzed. A power analysis using G∗ Power 3 software determined a needed sample size of 157 participants. Statistical analysis employed SPSS 26, utilizing descriptive statistics, Chi Square, Mann-Whitney, Kaplan-Meier with log-rank test, and Cox regression for predictor identification.

RESULTS

The cohort was predominantly male (79.1%) and diabetic (59.2%). Redo revascularization need was 15.3%, increasing with pMAC scores: 3.3% (low), 24.5% (medium), and 50% (high) (P < 0.001). MLLA frequency also rose with pMAC scores: 6.7%, 27.5%, and 50% respectively (P < 0.001). Higher pMAC scores correlated with a higher incidence of MALE (P = 0.029). Multivariate analysis showed medium pMAC (hazard ratio (HR) 4.159, P = 0.002), high pMAC (HR 7.366, P = 0.015), and Global Limb Anatomic Staging System (GLASS) stage 3 (HR 3.529, P = 0.011) as independent MLLA predictors. Redo revascularization predictors included female sex (HR 2.106, P = 0.063), Black race (HR 64.498, P = 0.001), medium pMAC (HR 6.812, P = 0.002), high pMAC (HR 11.455, P = 0.008), and GLASS stage 3 (HR 2.899, P = 0.037).

CONCLUSIONS

The pMAC score effectively predicts MALE in CLTI patients and enhances risk stratification. Using both, pMAC scores and GLASS stages enhances predictive accuracy, identifying patients at higher risk for MLLA, informing clinical decision-making and therapeutic strategies.

Medial arterial calcification of the lower limbs in diabetes: Time for awareness? A short narrative review

In patients with diabetes, peripheral arterial disease, particularly below the knee, is associated with medial arterial calcification. This is a frequent and potentially serious complication, affecting all types of diabetes. In recent years, our understanding of the pathophysiology and clinical significance of medial arterial calcification has improved considerably. Here, we offer a short narrative review of the epidemiology, clinical consequences, and pathophysiology of this complication. Now that medial arterial calcification of the lower limbs is better understood, we also focus on the prospect of treatments targeting arterial calcification.

Dichotomous grouping of peripheral arterial calcification grades: A practical predictor of outcome after endovascular therapy in peripheral arterial disease

BACKGROUND

There is a general agreement that arterial calcification affects the results of endovascular therapy for peripheral arterial disease (PAD). In addition to lacking evidence for their impact, existing calcification scores are complex, and not practical in everyday decision making. The global limb anatomic staging system (GLASS) adopted dichotomous grouping of calcification grades.

OBJECTIVE

In this study we aim to investigate the impact of peripheral arterial calcification scoring after dichotomous grouping on midterm outcomes following endovascular therapy for PAD.

METHODS

This prospective study included all consecutive patients with PAD indicated for endovascular therapy procedure who presented to our tertiary referral center in the period between October 2020 and October 2021. Patients were grouped into Group A (n = 40): with no-to mild calcification (PACSS grade 0,1 and 2), and Group B (n = 53): with severe calcification (PACSS grades 3 and 4). Primary endpoints included technical success rate, primary patency rates, and major adverse limb events rate (MALE) during 2 years of follow-up.

RESULTS

The mean age of the studied cases (n = 93) was 59.31 ± 6.46 years (range 50-75). 70 patients (75.3%) were males, and 23 (24.7%) were females. There was no statistically significant difference between the two groups regarding technical success rate (97.5% in group A versus 94.33% in Group B, p = .457). The Primary patency rate after 1 year was lower in group B (74%) compared to group A (89.7%), but this difference was not statistically significant (p = .059). However, the 2-year primary patency rate was significantly lower in group B compared to group A (64% versus 84.6% respectively, p = .034). MALE rate after 2 years was significantly higher in group B (28%) as compared to group A (10.4%), P = .048. Studying suspected risk factors revealed that severe calcification was more common in patients with ischemic heart disease (34%) and chronic kidney disease (11%), P= .003 and .002 respectively. Logistic regression analysis showed that patients suffered from IHD and those with length of lesion ≥ 5 cm are about five times more likely to have severe calcification compared to their counterparts (OR = 4.875, 95%CI = 1.293-18.383, p = .019, and OR = 4.513, 95% CI = 11.138-17.893, p = .032), respectively.

CONCLUSION

The presence of severe calcification is associated with significantly lower midterm primary patency rates and higher rate of major adverse limb events after endovascular intervention for lower limb denovo arterial lesions.

Inter- and Intra-observer Agreement of the Peripheral Arterial Calcium Scoring System in Patients Undergoing (Infra)Popliteal Endovascular Interventions

PURPOSE

Peripheral arterial calcification is an important predictor of outcomes after both conservative and endovascular treatment. Digital subtraction angiography (DSA)-based calcification scores are limited by low sensitivity and inter-observer agreement. The Peripheral Arterial Calcium Scoring System (PACSS) assesses the severity of target lesion calcification. The newly introduced modified PACSS (mPACSS) also evaluates target vessel calcification. This study aimed to assess the inter- and intra-observer reliability of PACSS and mPACSS on computed tomography angiography (CTA) in (infra)popliteal endovascular interventions.

METHODS

A random sample of 50 limbs from the prospective multicenter Dutch Chronic Lower Limb-Threatening Ischemia Registry (THRILLER) were included. Three experienced independent raters scored PACSS on CTA. Three months later, one blinded rater assessed the same 50 CTA scans, keeping track of assessment time. The reliability of the original 5-step PACSS, a simplified binary PACSS (0-2 vs 3-4) and the 7-step mPACSS were tested using Cohen's and Fleiss' kappa statistics.

RESULTS

In total, 50 limbs (mean age 70.1 ± 11.0, 29 men) with 41 popliteal and 40 infrapopliteal lesions were scored. Inter-observer agreement of PACSS and binary PACSS were moderate (κ = 0.60) and substantial (κ = 0.72), respectively, while intra-observer agreement was almost perfect in both scores (κ = 0.86). Inter- and intra-observer agreement of mPACSS were moderate (κ = 0.48) and substantial (κ = 0.77), respectively. Mean assessment time for an experienced rater was 3.43 ± 0.93 min per CTA scan.

CONCLUSION

Both the semi-quantitative PACSS and mPACSS scores for (infra)popliteal arteries can be performed reliably on pre-operative CTA.

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.

The Association between Fatty Liver Index and Lower Limb Arterial Calcification in Patients with Type 2 Diabetes Mellitus

Background

Peripheral arterial calcification is a prevalent condition in patients with type 2 diabetes mellitus (T2DM), resulting in lower-limb amputation and reduced life quality. Non-alcoholic fatty liver disease (NAFLD), which can be simply evaluated using the fatty liver index (FLI), is closely associated with T2DM development. In this study, we aimed to explore the relationship between FLI and lower limb arterial calcification (LLAC) in T2DM patients and to reveal the value of T2DM patients with NAFLD in predicting the occurrence of LLAC.

Methods

A total of 77 T2DM patients with LLAC who underwent comprehensive physical and health examinations, serological examinations, as well as lower limb computed tomography imaging at Sun Yat-sen Memorial Hospital of Sun Yat-sen University between January 2018 and January 2019 were enrolled in this study. The FLI was calculated using body mass index, waist circumference, triglycerides, and γ-glutamyl transferase. Additionally, LLAC was evaluated using computed tomography with the Agatston scoring algorithm. The patients were divided into three groups based on their FLI values: Non-liver disease group (FLI <30, n = 29), borderline-liver disease group (30 ≤ FLI < 60, n = 32), and NAFLD group (FLI ≥60, n = 16). Univariate and multivariate binary logistic regression analyses were employed to investigate the association between FLI and LLAC in T2DM patients. Furthermore, differences in LLAC among groups were analyzed using post-hoc multiple comparisons and ordinal logistic regression model analysis.

Results

Univariate and multivariate analyses showed that age and FLI influenced LLAC severity in T2DM patients. Moreover, T2DM patients in the NAFLD group had significantly lower LLAC scores than those in the Non-liver disease group. The correlation analysis showed that FLI was negatively associated with LLAC scores (R = -0.31, p = 0.006), while age was positively associated (R = 0.361, p = 0.001).

Conclusions

Our study revealed an inverse relationship between FLI and the degree of LLAC. This indicates that, based on evidence in the current research, NAFLD may not be reliable as a predictor of LLAC in T2DM patients.

Intravascular lithotripsy in infra-popliteal peripheral artery disease

Chronic limb-threatening ischemia (CLTI) carries a significant risk of limb loss and thus demands urgent attention. Calcified atherosclerotic disease affecting the infra-popliteal (IP) arteries poses a formidable challenge for effective revascularization due to the narrow vessel diameter and the common presence of extensively calcified, long occlusive lesions. Intravascular lithotripsy (IVL) is an endovascular treatment that induces microfractures in the medial calcifications of blood vessels, thereby facilitating the clearance of calcified obstructive arterial lesions. This review assesses the growing body of evidence from multiple prospective studies that have investigated the role of IVL in the treatment of peripheral arterial disease (PAD) involving the IP segment. The clinical efficacy of IVL has been extensively studied and validated in various trials and real-world experiences. These studies consistently demonstrate IVL's ability to achieve vessel preparation, with excellent procedural success rates and low rates of major adverse events. Moreover, IVL has shown remarkable versatility, proving effective across a wide spectrum of PAD, including iliac artery disease, femoropopliteal disease and IP calcified disease. The available results from existing literature are encouraging and demonstrates safety and efficacy of the technology in treating calcified PAD. Additional studies on a larger scale are needed to better understand its long-term effects.

Perioperative Risk Factors for Early Major Amputation Following First-Time Diabetic Forefoot Amputation

BACKGROUND

Despite a meticulous multidisciplinary team approach, limb salvage remains uncertain even after the initial forefoot amputation in patients with end-stage diabetes. Which of many factors strongly influence the early failure of the limb salvage strategy remains unknown. This study aimed to analyze perioperative independent risk factors for major amputation within 1 year following first-time diabetic forefoot amputation.

METHODS

Perioperative variables of 808 diabetic forefoot amputations performed in a tertiary referral center specialized for organ transplantation and end-stage diabetes were analyzed. Major amputations were performed in 104 patients (12.9%) throughout follow-up, and 77 (74%) of 104 patients had their major amputation within 1 year. Cox proportional hazards were examined to assess the risk factors for major amputation performed within 1 year.

RESULTS

In univariate analysis, 18 possible risk factors significantly differed between patients with and without early major amputation. In stepwise multivariable analysis, chronic renal failure (CRF), peritoneal dialysis, and bilateral initial amputation were strong risk factors for early major amputation, with hazard ratios of 2.973 (95% CI 1.805-4.896, P < .0001), 2.558 (95% CI 1.113-5.881, P = .027), and 2.515 (95% CI 1.318-4.798, P = .005), respectively.

CONCLUSION

Regardless of kidney transplantation (KT) status, CRF strongly predicts >20% chance of major amputation within 1 year after the first diabetic forefoot amputation.

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.

Intravascular lithotripsy in peripheral lesions with severe calcification and its use in TAVI procedure - a meta-analysis

Background: Heavily calcified peripheral artery lesions increase the risk of vascular complications, constituting a severe challenge for the operator during catheter-based cardiovascular interventions. Intravascular Lithotripsy (IVL) technology disrupts subendothelial calcification by using localized pulsative sonic pressure waves and represents a promising technique for plaque modification in patients with severe calcification in peripheral arteries. Purpose: Our aim was to systematically review and summarize available data regarding the safety and efficacy of IVL in preparing severely calcified peripheral arteries and its use in Transcatheter Aortic Valve Implantation (TAVI). Patients and methods: This study was conducted according to the PRISMA guidelines. We systematically searched PubMed, SCOPUS, and Cochrane databases from their inception to February 23, 2023, for studies assessing the characteristics and outcomes of patients undergoing IVL in the peripheral vasculature. The diameter of the vessel lumen before and after IVL was estimated. The occurrence of peri-procedural complications was assessed using a random-effects model. Results: 20 studies with a total of 1,223 patients with heavily calcified peripheral lesions were analysed. The mean age of the cohort was 70.6 ± 17.4 years. Successful IVL delivery achieved in 100% (95% CI: 100%-100%, I2 = 0%), with an increase in the luminal diameter (SMD: 4.66, 95% CI: 3.41-5.92, I2 = 90.8%) and reduction in diameter stenosis (SMD: -4.15, 95% CI: -4.75 to -3.55, I2 = 92.8%), and a concomitant low rate of complications. The procedure was free from dissection in 97% (95% CI: 91%-100%, I2 = 81.4%) while dissections of any type (A, B, C, or D) were observed in 6% (95% CI: 2%-10%, I2 = 85.3%) of the patients. Several rare cases of abrupt closure, no-reflow phenomenon, perforation, thrombus formation, and distal embolization were recorded. Finally, the subgroup analysis of patients who underwent a TAVI with IVL assistance presented successful implantation in 100% (95% CI: 100%-100%, I2 = 0%) of the cases, with only 4% (95% CI: 0%-12%, I2 = 68.96%) presenting dissections of any sort. Conclusions: IVL seems to be an effective and safe technique for modifying severely calcified lesions in peripheral arteries and it is a promising modality in TAVI settings. Future prospective studies are needed to validate our results.

Clinical implications of diverse calcification patterns in endovascular therapy for femoral-popliteal arterial occlusive disease

OBJECTIVE

The aim of this study was to investigate whether intimal arterial calcification (IAC) and medial arterial calcification (MAC) are correlated with the various clinical outcomes following endovascular therapy (EVT) for peripheral arterial disease (PAD).

METHODS

This single-center retrospective study comprised 154 consecutively hospitalized individuals with PAD who underwent EVT for de novo femoral-popliteal calcific lesions from January 2016 to July 2021. The predominant calcification patterns of IAC and MAC were assessed using a semi-quantitative computed tomography scoring system. The Kaplan-Meier method and Cox regression were conducted to evaluate the correlations between calcification patterns and medium- to long-term outcomes.

RESULTS

The distribution of calcification patterns was as follows: IAC in 111 patients (72%) and MAC in 43 patients (28%). No remarkable variation was noted between the IAC and MAC groups regarding age (P = .84) and gender (P = .23). The MAC group indicated lower rates of 4-year primary patency, assisted primary patency, secondary patency, and amputation-free survival (AFS) compared with the IAC group (24% ± 7% vs 40% ± 6%; P = .003; 30% ± 8% vs 51% ± 6%; P = .001; 51% ± 8% vs 65% ± 5%; P = .004; and 43% ± 9% vs 76% ± 5%; P < .001, respectively). There was no significant difference in the rate of freedom from clinically driven target lesion revascularization between the MAC and IAC groups (63% ± 10% vs 73% ± 5%; P = .26). Stepwise multivariable Cox regression analysis demonstrated that MAC was associated with poor patency (hazard ratio, 1.81; 95% confidence interval, 1.12-2.93; P = .016) and AFS (hazard ratio, 2.80; 95% confidence interval, 1.52-5.16; P = .001).

CONCLUSIONS

Compared with IAC, MAC is independently associated with lower medium- to long-term patency and AFS after EVT for de novo femoral-popliteal occlusive lesions.

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.

Doppler Sonographic Characteristics and Clinical Outcomes of Diabetic Foot Syndrome: A 5-Year Audit from a Tertiary Hospital in Northern Nigeria

Background

Diabetes foot syndrome is one of the common complications of diabetes. Detailed information on the clinical and vascular characteristics of patients with diabetic foot disease in relation to the outcome of the care provided to these patients will be useful to policymakers and clinicians in early detection and timely interventions for the prevention of disabling complications.

Materials and Methods

This is a review of patients with diabetic foot managed in Aminu Kano Teaching Hospital over 5 years (January 2017-May 2022). The sociodemographic characteristics, Wagner classification of the foot, Doppler sonographic characteristics and clinical outcomes, etc., were reviewed.

Results

A total of 51 patients were reviewed. Males and females accounted for 56.8% and 43.1%, respectively. Twenty-five patients had Wagner grade 4 ulcers, and fewer patients had Wagner grade 1 and 5-foot ulcers. The mean ± standard deviation Doppler arterial intimal media thickness was 1.53 ± 0.33 (range 0.90-2.40 mm). The majority of DFS patients had Doppler sonographic lesions on the right lower limb 28 (54.9%) only, and 11 (21.6%) of the lesions were bilateral. The posterior tibial artery 11 (21.6%) was the most involved arterial segment with plaques, followed by a combination of popliteal and tibial arterial 10 (19.6%) segments. At 6 months, 45.2% had limb amputation, 17.6% healed ulcers, 17.6% delayed wound healing, and 9.8% died.

Conclusion

There is an unacceptably high prevalence of poor treatment outcomes, thus, contributing to a huge burden of care to patients living with diabetes. There is a strong association between severe arterial stenosis detected by Doppler ultrasound and higher rates of amputations.

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.

Novel Glycomimetics Protect against Glycated Low-Density Lipoprotein-Induced Vascular Calcification In Vitro via Attenuation of the RAGE/ERK/CREB Pathway

Heparan sulphate (HS) can act as a co-receptor on the cell surface and alterations in this process underpin many pathological conditions. We have previously described the usefulness of mimics of HS (glycomimetics) in protection against β-glycerophosphate-induced vascular calcification and in the restoration of the functional capacity of diabetic endothelial colony-forming cells in vitro. This study aims to investigate whether our novel glycomimetic compounds can attenuate glycated low-density lipoprotein (g-LDL)-induced calcification by inhibiting RAGE signalling within the context of critical limb ischemia (CLI). We used an established osteogenic in vitro vascular smooth muscle cell (VSMC) model. Osteoprotegerin (OPG), sclerostin and glycation levels were all significantly increased in CLI serum compared to healthy controls, while the vascular calcification marker osteocalcin (OCN) was down-regulated in CLI patients vs. controls. Incubation with both CLI serum and g-LDL (10 µg/mL) significantly increased VSMC calcification vs. controls after 21 days, with CLI serum-induced calcification apparent after only 10 days. Glycomimetics (C2 and C3) significantly inhibited g-LDL and CLI serum-induced mineralisation, as shown by a reduction in alizarin red (AR) staining and alkaline phosphatase (ALP) activity. Furthermore, secretion of the osteogenic marker OCN was significantly reduced in VSMCs incubated with CLI serum in the presence of glycomimetics. Phosphorylation of cyclic AMP response element-binding protein (CREB) was significantly increased in g-LDL-treated cells vs. untreated controls, which was attenuated with glycomimetics. Blocking CREB activation with a pharmacological inhibitor 666-15 replicated the protective effects of glycomimetics, evidenced by elevated AR staining. In silico molecular docking simulations revealed the binding affinity of the glycomimetics C2 and C3 with the V domain of RAGE. In conclusion, these findings demonstrate that novel glycomimetics, C2 and C3 have potent anti-calcification properties in vitro, inhibiting both g-LDL and CLI serum-induced VSMC mineralisation via the inhibition of LDLR, RAGE, CREB and subsequent expression of the downstream osteogenic markers, ALP and OCN.

Peripheral arterial disease treatment planning using noninvasive and invasive imaging methods

With the growing prevalence and mortality of peripheral arterial disease, preoperative assessment, risk stratification, and determining the correct indication for endovascular and open surgical procedures are essential for therapeutic decision-making. The effectiveness of interventional procedures is significantly influenced by the plaque composition and calcification pattern. Therefore, the identification of patients for whom endovascular treatment is the most appropriate therapeutic solution often remains a challenge. The most commonly used imaging techniques have their own limitations and do not provide findings detailed enough for specific, personalized treatment planning. Using state-of-the-art noninvasive and invasive imaging modalities, it is now possible to obtain a view, not only of the complex vascular anatomy and plaque burden of the lower extremity arterial system, but also of complex plaque structures and various pathologic calcium distribution patterns. In the future, as these latest advancements in diagnostic methods become more widespread, we will be able to obtain more accurate views of the plaque structure and anatomic complexity to guide optimal treatment planning and device selection. We reviewed the implications of the most recent invasive and noninvasive lower extremity imaging techniques and future directions.

Lower limb arterial calcification and its clinical relevance with peripheral arterial disease

Lower limb arterial calcification (LLAC) is associated with an increased risk of mortality and it predicts poor outcomes after endovascular interventions in patients with peripheral artery disease (PAD). Detailed histological analysis of human lower artery specimens pinpointed the presence of LLAC in two distinct layers: the intima and the media. Intimal calcification has been assumed to be an atherosclerotic pathology and it is associated with smoking and obesity. It becomes instrumental in lumen stenosis, thereby playing a crucial role in disease progression. On the contrary, medial calcification is a separate process, systematically regulated and linked with age advancement, diabetes, and chronic kidney disease. It prominently interacts with vasodilation and arterial stiffness. Given that both types of calcifications frequently co-exist in PAD patients, it is vital to understand their respective mechanisms within the context of PAD. Calcification can be easily identifiable entity on imaging scans. Considering the highly improved abilities of novel imaging technologies in differentiating intimal and medial calcification within the lower limb arteries, this review aimed to describe the distinct histological and imaging features of the two types of LLAC. Additionally, it aims to provide in-depth insight into the risk factors, the effects on hemodynamics, and the clinical implications of LLAC, either occurring in the intimal or medial layers.

Five-Year Outcomes after Paclitaxel Drug-Coated Balloon Treatment of Femoropopliteal Lesions in Diabetic and Chronic Limb-Threatening Ischemia Cohorts: IN.PACT Global Study Post Hoc Analysis

PURPOSE

To summarize the 5-year outcomes of drug-coated balloon (DCB) for the treatment of femoropopliteal lesions in patients with diabetes mellitus (DM) or chronic limb-threatening ischemia (CLTI) compared to non-DM and intermittent claudication (IC).

METHODS

The IN.PACT Global study was a real-world prospective, multicenter, international, single-arm study that enrolled 1535 participants. Post hoc analyses were conducted for participants with DM (n = 560) versus non-DM (n = 842) and CLTI (n = 156) versus IC (n = 1246). Assessments included freedom from clinically driven target lesion revascularization (CD-TLR) through 60 months, a composite safety outcome (freedom from device- and procedure-related death through 30 days, and freedom from major target limb amputation and freedom from CD-target vessel revascularization within 60 months), and major adverse events (MAEs).

RESULTS

Kaplan-Meier estimates of 60-month freedom from CD-TLR were 67.7% and 70.5% (p = 0.25) in the DM and non-DM cohorts; and 60.7% and 70.5% (p = 0.006) in the CLTI and IC cohorts. The Kaplan-Meier 60-month composite safety outcomes were 65.1% DM versus 68.9% non-DM (p = 0.12); 53.2% CLTI versus 69.1% IC (p < 0.001). Between DM and non-DM, MAE rates were not significantly different through 60 months except for all-cause mortality which was higher in DM (23.8% versus 16.6%; p < 0.001). Participants with CLTI had a higher cumulative incidence of major target limb amputation (6.8% versus 1.1%; p < 0.001) and all-cause mortality (37.4% versus 17.4%; p < 0.001) through 60 months compared to IC.

CONCLUSIONS

In this real-world study, 5-year reintervention rates following DCB angioplasty were similar between DM and non-DM, but mortality rates were expectedly higher in patients with DM. Reintervention, mortality, and amputation rates were all higher in CLTI patients compared to IC, which is consistent with the known frailty of this patient population.

LEVEL OF EVIDENCE

Level 3, Non-randomized controlled cohort/follow-up study.

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.

High relative amount of nodular calcification in femoral plaques is associated with milder lower extremity arterial disease

BACKGROUND

Clinical implications of different types of vascular calcification are poorly understood. The two most abundant forms of calcification, nodular and sheet calcification, have not been quantitatively analyzed in relation to the clinical presentation of lower extremity arterial disease (LEAD).

METHODS

The study analyzed 51 femoral artery plaques collected during femoral endarterectomy, characterized by the presence of > 90% stenosis. Comprehensive clinical data was obtained from patient records, including magnetic resonance angiography (MRA) images, toe pressure and ankle brachial index measurements and laboratory values. The plaques were longitudinally sectioned, stained with Hematoxylin and Eosin and digitized in a deep learning platform for quantification of the relative area of nodular and sheet calcification to the plaque section area. A deep learning artificial intelligence algorithm was designed and independently validated to reliably quantify nodular calcification and sheet calcification. Vessel measurements and quantity of each calcification category was compared to the risk factors and clinical presentation.

RESULTS

On average, > 90% stenosed vessels contained 22.4 ± 12.3% of nodular and 14.5 ± 11.8% of sheet calcification. Nodular calcification area proportion in lesions with > 90% stenosis is associated with reduced risk of critically low toe pressure (< 30 mmHg) (OR = 0.910, 95% CI = 0.835-0.992, p < 0.05), severely lowered ankle brachial index (< 0.4) (OR = 0.912, 95% CI = 0.84-0.986, p < 0.05), and semi-urgent operation (OR = 0.882, 95% CI = 0.797-0.976, p < 0.05). Sheet calcification did not show any significant association.

CONCLUSIONS

Large amount of nodular calcification is associated with less severe LEAD. Patients with nodular calcification may have better flow reserves despite local obstruction.

Analysis of repeated lesions after diabetic forefoot amputation

AIM

This study was performed to analyze the clinical characteristics, related factors, and prognosis of repeated lesions after diabetic forefoot amputation.

METHODS

The medical records of 998 patients who underwent forefoot amputation because of their diabetic feet from March 2002 to February 2021 were retrospectively analyzed. Of the 508 selected patients with a follow-up period of at least 6 months, 288 had repeated lesions in the forefoot, and 220 did not have repeated lesions. The related factors of repeated lesions were compared and analyzed. Of the patients with repeated lesions, 142 and 104 on the ipsilateral and contralateral sides, respectively were also compared and examined.

RESULTS

Repeated lesions were statistically significant in diabetic polyneuropathy, vascular calcification, and dialysis. However, the anatomical positions of diabetic foot lesions, causes of lesions, anatomical amputation levels, number of surgeries, and management duration had no significant differences. Contralateral lesions occurred 8 months later than ipsilateral lesions, but reamputation above the Lisfranc joint was more frequent and prognosis was poorer.

CONCLUSIONS

Repeated lesions were affected by general conditions, and the contralateral side must be carefully examined after diabetic forefoot amputation.

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.

Impact of Sodium-Glucose Cotransporter 2 (SGLT2) Inhibitors on Arterial Stiffness and Vascular Aging-What Do We Know So Far? (A Narrative Review)

Vascular aging, early vascular aging or supernormal vascular aging are concepts used for estimating the cardiovascular risk at a certain age. From the famous line of Thomas Sydenham that "a man is as old as his arteries" to the present day, clinical studies in the field of molecular biology of the vasculature have demonstrated the active role of vascular endothelium in the onset of cardiovascular diseases. Arterial stiffness is an important cardiovascular risk factor associated with the occurrence of cardiovascular events and a high risk of morbidity and mortality, especially in the presence of diabetes. Sodium-glucose cotransporter 2 inhibitors decrease arterial stiffness and vascular resistance by decreasing endothelial cell activation, stimulating direct vasorelaxation and ameliorating endothelial dysfunction or expression of pro-atherogenic cells and molecules.

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.

Automatic measurement of vascular calcifications in patients with aorto-iliac occlusive disease to predict the risk of re-intervention after endovascular repair

OBJECTIVE

There is currently a lack of consensus and tools to easily measure vascular calcification using computed tomography angiography (CTA). The aim of this study was to develop a fully automatic software to measure calcifications and to evaluate the interest as predictive factor in patients with aorto-iliac occlusive disease.

METHODS

This study retrospectively included 171 patients who had endovascular repair of an aorto-iliac occlusive lesion at the University Hospital of Nice between January 2011 and December 2019. Calcifications volumes were measured from CT-angiography (CTA) using an automatic method consisting in 3 sequential steps: image pre-processing, lumen segmentation using expert system and deep learning algorithms and segmentation of calcifications. Calcification volumes were measured in the infrarenal abdominal aorta and the iliac arterial segments, corresponding to the common and the external iliac arteries.

RESULTS

Among 171 patients included with a mean age of 65 years, the revascularization was performed on the native external and internal iliac arteries in respectively: 83 patients (48.5%); 107 (62.3%) and 7 (4.1%). The mean volumes of calcifications were 2759 mm³ in the infrarenal abdominal aorta, 1821 mm³ and 1795 mm³ in the right and left iliac arteries. For a mean follow up of 39 months, TLR was performed in 55 patients (32.2%). These patients had higher volume of calcifications in the right and left iliac arteries, compared with patients who did not have a re-intervention (2274 mm³ vs 1606 mm³, p=0.0319 and 2278 vs 1567 mm³, p=0.0213).

CONCLUSION

The development of a fully automatic software would be useful to facilitate the measurement of vascular calcifications and possibly better inform the prognosis of patients.

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.

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.

Resveratrol Alleviates Vascular Endothelial Damage Caused by Lower-Extremity Ischemia Reperfusion (I/R) through Regulating Keap1/Nrf2 Signaling-Mediated Oxidative Stress

The present study aims to investigate the protective effects of Resveratrol (RSV) against vascular endothelial damage caused by lower-extremity I/R and the underlying preliminary mechanism. The in vitro hypoxia reoxygenation (HR) model was established on HUVECs. Lower-extremity I/R model was established on rats followed by being treated with RSV and the pathological state of artery was evaluated by HE and EVG staining, while the apoptotic state of artery was detected by TUNEL assay. The cell viability was detected by MTT assay and the apoptotic state of cells was determined by Hoechst test and flow cytometry assay. DCFH-DA staining was used to measure the level of ROS and the production of MDA and SOD was measured by commercial kits. The expression level of Nrf2, Keap1, HO-1, Bcl-2, Bax, and Caspase-3 in cells was determined by Western blot. Nrf2 was knocked down by siRNA technology. Overall, our data indicated that increased cell viability, declined apoptotic rate, and alleviated oxidative stress were observed in RSV treated HR HUVECs, which were significantly reversed by knocking down Nrf2. Animal experiment revealed that the pathological and apoptotic state of femoral artery were dramatically ameliorated by the treatment of RSV, accompanied by the alleviated oxidative stress, which were abolished by the co-administration of ML385, an inhibitor of Nrf2. Taken together, our data revealed that RSV might alleviate vascular endothelial injury induced by lower-extremity I/R injury through regulating Keap1/Nrf2 signaling-mediated oxidative stress.

Pilot study of contrast-free MRI reveals significantly impaired calf skeletal muscle perfusion in diabetes with incompressible peripheral arteries

Patients with diabetes mellitus (DM) are more likely to have densely calcified lesions in the below-the-knee tibial arteries. However, the relationship between peripheral arterial calcification and local skeletal muscle perfusion has not been explored. Thirty subjects were prospectively recruited into three groups in this pilot study: (1) Non-DM: 10 people without DM; (2) DM, ABI < 1.3: 10 people with DM and normal ankle-brachial index (ABI) (0.9-1.3); and (3) DM, ABI ⩾ 1.3: 10 people with DM and ABI ⩾ 1.3. All subjects underwent calf perfusion measurements at rest and during an isometric plantarflexion contraction exercise within the magnetic resonance imaging (MRI) system. The noncontrast MRI techniques were applied to quantitatively assess skeletal muscle blood flow (SMBF) and oxygen extraction fraction (SMOEF) in medial gastrocnemius and soleus muscles. Both SMBF and SMOEF reserves were calculated as the ratio of the exercise value to the resting value. Exercise SMBF and SMOEF values in the medial gastrocnemius muscle were lower in the two DM groups than in the non-DM group (p < 0.05). The SMBF reserve in medial gastrocnemius was significantly lower in the DM, ABI ⩾ 1.3 group compared to the DM, ABI < 1.3 group (p < 0.05). This study demonstrates that people with DM and calcified arteries had lower perfusion in gastrocnemius muscle compared to those without DM and those with DM and a normal ABI.

Circulating Levels of Dephosphorylated-Uncarboxylated Matrix Gla Protein in Patients with Acute Coronary Syndrome

Vascular calcification contributes to the pathogenesis of coronary artery disease while matrix Gla protein (MGP) was recently identified as a potent inhibitor of vascular calcification. MGP fractions, such as dephosphorylated-uncarboxylated MGP (dp-ucMGP), lack post-translational modifications and are less efficient in vascular calcification inhibition. We sought to compare dp-ucMGP levels between patients with acute coronary syndrome (ACS), stratified by ST-elevation myocardial infarction (STEMI) and non-ST-elevation myocardial infarction (NSTEMI) status. Physical examination and clinical data, along with plasma dp-ucMGP levels, were obtained from 90 consecutive ACS patients. We observed that levels of dp-ucMGP were significantly higher in patients with NSTEMI compared to STEMI patients (1063.4 ± 518.6 vs. 742.7 ± 166.6 pmol/L, p < 0.001). NSTEMI status and positive family history of cardiovascular diseases were only independent predictors of the highest tertile of dp-ucMGP levels. Among those with NSTEMI, patients at a high risk of in-hospital mortality (adjudicated by GRACE score) had significantly higher levels of dp-ucMGP compared to non-high-risk patients (1417.8 ± 956.8 vs. 984.6 ± 335.0 pmol/L, p = 0.030). Altogether, our findings suggest that higher dp-ucMGP levels likely reflect higher calcification burden in ACS patients and might aid in the identification of NSTEMI patients at increased risk of in-hospital mortality. Furthermore, observed dp-ucMGP levels might reflect differences in atherosclerotic plaque pathobiology between patients with STEMI and NSTEMI.

Calcifying characteristics of peripheral vascular smooth muscle cells of chronic kidney disease patients with critical limb ischemia

The role of vascular smooth muscle cells (VSMCs) in vascular calcification, which is related to chronic kidney disease (CKD), has been studied in greater detail in the major arteries relative to the peripheral arteries. We compared the calcifying characteristics of peripheral VSMCs relative to non-pathologic major VSMCs in patients with severe peripheral artery disease (PAD). We isolated peripheral VSMCs from the posterior tibial artery of 10 patients with CKD who underwent below-knee amputation for critical limb ischemia (CLI). Using normal human aortic VSMCs as a control group, we cultured the cells in normal and high phosphate media for 10 days, and subsequently tested by immunofluorescence staining. We compared the calcification levels between the two groups using various assays, tests for cell viability, and scanning electron microscopy. As a result, calcification of pathologic peripheral VSMCs increased significantly with time (p = 0.028) and was significantly higher than that in human aortic VSMCs in calcium assays (p = 0.043). Dead cells in the pathologic VSMC group were more distinct in high phosphate media than in human aortic VSMCs. In conclusion, VSMCs from the peripheral artery of patients with severe CKD and CLI who underwent amputation surgery showed marked calcifying characteristics compared to normal human aortic VSMCs.

Early and Midterm Experience With the Absorb Everolimus-Eluting Bioresorbable Vascular Scaffold in Asian Patients With Chronic Limb-Threatening Ischemia: One-Year Clinical and Imaging Outcomes From the DISAPEAR Registry

Purpose: To report an experience with the Absorb bioresorbable vascular scaffold (BVS) in an Asian cohort with chronic limb-threatening ischemia (CLTI) from the DISAPEAR (Drug Impregnated Bioresorbable Stent in Asian Population Extremity Arterial Revascularization) registry. Materials and Methods: A retrospective analysis was conducted of 41 patients (median age 64 years; 23 men) with CLTI owing to >50% de novo infrapopliteal lesions (n=53) treated with the Absorb BVS between August 2012 and June 2017. The majority of patients (37, 90%) had diabetes, 24 (59%) had ischemic heart disease, and 39 (95%) had Rutherford category 5/6 ischemia with tissue loss. The mean lesion length was 22.7±17.2 mm; 10 (24%) lesions were severely calcified. Assessments included technical success, primary patency, freedom from clinically-driven target lesion revascularization (CD-TLR), amputation-free survival, limb salvage, complete wound healing, resolution of rest pain, and resolution of CLTI without TLR at 6 and 12 months after the index intervention. Results: Overall, 69 scaffolds were implanted in the 53 lesions, with 100% technical success. There were no deaths within 30 days of the index procedure. The primary patency rates at 6 and 12 months were 95% and 86%, respectively. The corresponding rates of freedom from CD-TLR were 98% and 93%, respectively. Freedom from major amputation was 98% at both time points, and amputation-free survival was 93% and 85% at 6 and 12 months after the index procedure. Wound healing occurred in 31 patients (79%) with Rutherford category 5/6 ischemia by the end of 12 months. Conclusion: The Absorb BVS demonstrated good 1-year patency and clinical outcomes in CLTI patients with complex infrapopliteal disease.

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.

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.

CT calcification patterns of peripheral arteries in patients without known peripheral arterial disease

PURPOSE

In the last few years histologic studies of peripheral arteries have shown that both intimal and medial calcifications are found in patients in an early, asymptomatic stage and that differentiation between medial and intimal calcifications is possible. The aim of this study was to assess the computed tomography (CT) calcification characteristics in peripheral arteries and to explore potential patterns in subjects without peripheral arterial disease (PAD).

METHOD

Retrospectively, 204 patients without known PAD were studied. The thin slice CT-imaging characteristics severity, annularity, thickness and continuity were scored in the following arteries: plantar and dorsal, crural, femoro-popliteal, iliac and the abdominal aorta. Interrelation was assessed using linear regression and significance was tested by Chi-Square tests.

RESULTS

In the crural arteries two calcification patterns with strong associations were found. Pattern 1: continuous-annular 93.5 % (29/31), continuous-thin and thin-annular both 73 % (27/37, p < 0.001) and pattern 2: thick-discontinuous 91.7 % (44/48), thick-dotted 68.8 % (33/48), patchy-dotted 59.3 % (16/27, p < 0.001). Similar associations were found in the femoro-popliteal artery, but not in the plantar, dorsal, iliac arteries and aorta.

CONCLUSIONS

In the crural and femoropopliteal arteries at least two morphological patterns can be distinguished on CT that, compared to a CT-histologically validated score, may represent an intimal and medial calcification pattern.

Lower Limb Arterial Calcification and Acute Thrombosis Risk in Patients with Peripheral Artery Disease

BACKGROUND

Calcification is closely related to in situ thrombosis secondary to plaque rupture in the coronary artery. However, the association between calcification in lower extremity arteries and acute thrombosis has not been assessed. We thus sought to determine whether lower limb arterial calcification (LLAC) was correlated with acute thrombosis in patients with symptomatic peripheral artery disease (PAD).

METHODS

We retrospectively reviewed consecutive patients presenting with symptomatic PAD between April 2017 and March 2018 who underwent lower extremity arterial evaluation by computed tomography (CT) angiography. Patient characteristics and cardiovascular risk factors were recorded, and LLAC scores were determined by noncontrast CT scans. Univariate and multivariate logistic regression was used to identify factors associated with acute thrombosis.

RESULTS

The record search identified 201 patients with symptomatic PAD, including 24 with acute thrombosis and 177 without. Patients in the acute thrombosis group were significantly younger (P = 0.04) and had less diabetes mellitus (P = 0.04). Patients with acute thrombosis had more advanced ischemia at presentation (P < 0.01) and higher amputation rate within 30 days (P < 0.01). Univariate regression showed a significant association among acute thrombosis and age, diabetes mellitus, and LLAC score; in multivariable analysis, only the LLAC score (odds ratio 0.60, 95% confidence interval 0.37-0.98) maintained an association with acute thrombosis after adjusting for relevant risk factors.

CONCLUSIONS

The LLAC score is independently and inversely associated with acute thrombosis in patients with PAD.