Systematic reviews and meta-analyses for more profitable strategies in peripheral artery disease

Cost-effectiveness of diagnostic imaging modalities in symptomatic patients with lower limb peripheral arterial disease: discrete event simulation model

Objective

Lower limb peripheral arterial disease in the symptomatic stage has a significant effect on patients´ functional disability. Before an intervention, an imaging diagnostic examination is necessary to determine the extent of the disability. This study evaluates cost-effectiveness of duplex ultrasonography (DUS), digital subtraction angiography (DSA), computed tomography angiography (CTA) and magnetic resonance angiography (MRA) in the diagnostics of symptomatic patients with lower limb peripheral arterial disease indicated for endovascular or surgical intervention.

Methods

Discrete event simulation was used to capture lifetime costs and effects. Costs were calculated from the perspective of the health care payer, and the effects were calculated as quality-adjusted life year's (QALY's). The cost-effectiveness analysis was performed to pairwise compare CTA, MRA and DSA with DUS as the baseline diagnostic modality. A scenario analysis and probabilistic sensitivity analysis were carried out to evaluate the robustness of the results.

Results

In the basic case, the DUS diagnostic was the least expensive modality, at a cost of EUR 10,778, compared with EUR 10,804 for CTA, EUR 11,184 for MRA, and EUR 11,460 for DSA. The effects of DUS were estimated at 5.542 QALYs compared with 5.554 QALYs for both CTA and MRA, and 5.562 QALYs for DSA. The final incremental cost-effectiveness ratio (ICER) value of all evaluated modalities was below the cost-effectiveness threshold whereas CTA has the lowest ICER of EUR 2,167 per QALY. However, the results were associated with a large degree of uncertainty, because iterations were spread across all cost-effectiveness quadrants in the probabilistic sensitivity analysis.

Conclusion

For imaging diagnosis of symptomatic patients with lower limb peripheral arterial disease, CTA examination appears to be the most cost-effective strategy with the best ICER value. Baseline diagnostics of the DUS modality has the lowest costs, but also the lowest effects. DSA achieves the highest QALYs, but it is associated with the highest costs.

Clinical recurrence and antiplatelet drug resistance among patients with lower limb ischemia

There is a high prevalence rate of peripheral artery disease worldwide, with estimated cases exceeding 200 million. Most patients are under-diagnosed and under-treated, and there is a lack of knowledge regarding the best therapeutic regimen and therapy duration, which leads to many cases of recurrence, complications, and amputations. This study aims to explore clinical recurrence, which was defined as the worsening of chronic peripheral artery disease requiring hospital admission, and its relationship with antiplatelet drug resistance among patients with lower limb ischemia. This cohort study includes both retrospective and prospective recruitment of patients with chronic lower limb ischemia. Platelet aggregation tests were offered to the patients. Between February 2018 and November 2020, 147 patients were recruited from King Abdullah University Hospital and followed up for at least 1 year. Platelet aggregation tests were done for 93 patients who agreed to participate in this part of the study. The prevalence of chronic lower limb ischemia was higher in young male patients who are current smokers with co-morbid diseases such as hypertension, diabetes mellitus, and/or dyslipidemia. There was a significant association only of clinical recurrence with younger age (P = .011) and with low platelets count in severe stages of the disease (P = .047). No significant association was found in terms of laboratory resistance. The clinical recurrence rates of chronic lower limb ischemia were higher in younger patients and among those with low platelet counts in the severe stages of the disease. Despite the laboratory responsiveness to anti-platelet therapy, we observed significant clinical resistance and increased recurrence rates.

Keratose Hydrogel Drives Differentiation of Cardiac Vascular Smooth Muscle Progenitor Cells: Implications in Ischemic Treatment

Peripheral artery disease (PAD) is a common vascular disorder in the extremity of limbs with limited clinical treatments. Stem cells hold great promise for the treatment of PAD, but their therapeutic efficiency is limited due to multiple factors, such as poor engraftment and non-optimal selection of cell type. To date, stem cells from a variety of tissue sources have been tested, but little information is available regarding vascular smooth muscle cells (VSMCs) for PAD therapy. The present study examines the effects of keratose (KOS) hydrogels on c-kit+/CD31- cardiac vascular smooth muscle progenitor cell (cVSMPC) differentiation and the therapeutic potential of the resultant VSMCs in a mouse hindlimb ischemic model of PAD. The results demonstrated that KOS but not collagen hydrogel was able to drive the majority of cVSMPCs into functional VSMCs in a defined Knockout serum replacement (SR) medium in the absence of differentiation inducers. This effect could be inhibited by TGF-β1 antagonists. Further, KOS hydrogel increased expression of TGF-β1-associated proteins and modulated the level of free TGF-β1 during differentiation. Finally, transplantation of KOS-driven VSMCs significantly increased blood flow and vascular densities of ischemic hindlimbs. These findings indicate that TGF-β1 signaling is involved in KOS hydrogel-preferred VSMC differentiation and that enhanced blood flow are likely resulted from angiogenesis and/or arteriogenesis induced by transplanted VSMCs.

Role of Lipid-Lowering Therapy in Peripheral Artery Disease

Atherosclerosis is a multifactorial, lipoprotein-driven condition that leads to plaque formation within the arterial tree, leading to subsequent arterial stenosis and thrombosis that accounts for a large burden of cardiovascular morbidity and mortality globally. Atherosclerosis of the lower extremities is called peripheral artery disease and is a major cause of loss in mobility, amputation, and critical limb ischemia. Peripheral artery disease is a common condition with a gamut of clinical manifestations that affects an estimated 10 million people in the United States of America and 200 million people worldwide. The role of apolipoprotein B-containing lipoproteins, such as LDL and remnant lipoproteins in the development and progression of atherosclerosis, is well-established. The focus of this paper is to review existing data on lipid-lowering therapies in lower extremity atherosclerotic peripheral artery disease.

Efficacy and safety of drug-coated balloon versus non-drug-coated balloon combined with bare metal stent implantation in treatment of patients with occlusions of the superficial femoral artery: a retrospective study in clinical practice

OBJECTIVE

To assess the efficacy and safety of drug-coated balloon and non-drug-coated balloon combined with bare metal stent implantation for the treatment of patients with occlusions of the superficial femoral artery.

METHODS

In this retrospective study, 83 patients with occlusions of the superficial femoral artery were included. Among them, 41 patients received paclitaxel drug coated balloon treatment combined with bare metal stent implantation treatment (experimental group), the remaining 42 received non-drug-coated balloon treatment (control group). Patients were followed up at 1, 6, and 12 months after surgery. The primary clinical assessments, including ankle brachial index (ABI), RutherFord grade, Doppler ultrasound, or CT angiography (CTA), were used to observe the patency of target vessels, perioperative and postoperative complications.

RESULTS

All the diseased vessels were successfully opened. There were no serious intraoperative complications such as vascular rupture or acute thrombosis. There was no significant difference in ankle brachial index, RutherFord grade, and total score between the two groups at one month and six months after operation (P>0.05). There was no significant difference in mortality, amputation rate, or thrombosis between the two groups (P>0.05). Twelve months after the operation, the ankle brachial index, Rutherford grade and total score of the experimental group were better than those of the control group (P<0.05). There was no significant difference in mortality, amputation rate, or thrombosis between the two groups (P>0.05).

CONCLUSION

Paclitaxel coated balloon is safe and effective in the treatment of superficial femoral arteriosclerosis occlusion. It can significantly improve the ABI and Rutherford grades of patients, and it had a higher patency rate and lower reconstruction rate, but it may affect the healing ability of foot ulcer.

Collateral Arteriogenesis Involves a Sympathetic Denervation That Is Associated With Abnormal α-Adrenergic Signaling and a Transient Loss of Vascular Tone

Stimulating collateral arteriogenesis is an attractive therapeutic target for peripheral artery disease (PAD). However, the potency of arteriogenesis-stimulation in animal models has not been matched with efficacy in clinical trials. This may be because the presence of enlarged collaterals is not sufficient to relieve symptoms of PAD, suggesting that collateral function is also important. Specifically, collaterals are the primary site of vascular resistance following arterial occlusion, and impaired collateral vasodilation could impact downstream tissue perfusion and limb function. Therefore, we evaluated the effects of arteriogenesis on collateral vascular reactivity. Following femoral artery ligation in the mouse hindlimb, collateral functional vasodilation was impaired at day 7 (17 ± 3 vs. 60 ± 8%) but restored by day 28. This impairment was due to a high resting diameter (73 ± 4 μm at rest vs. 84 ± 3 μm dilated), which does not appear to be a beneficial effect of arteriogenesis because increasing tissue metabolic demand through voluntary exercise decreased resting diameter and restored vascular reactivity at day 7. The high diameter in sedentary animals was not due to sustained NO-dependent vasodilation or defective myogenic constriction, as there were no differences between the enlarged and native collaterals in response to eNOS inhibition with L-NAME or L-type calcium channel inhibition with nifedipine, respectively. Surprisingly, in the context of reduced vascular tone, vasoconstriction in response to the α-adrenergic agonist norepinephrine was enhanced in the enlarged collateral (−62 ± 2 vs. −37 ± 2%) while vasodilation in response to the α-adrenergic antagonist prazosin was reduced (6 ± 4% vs. 22 ± 16%), indicating a lack of α-adrenergic receptor activation by endogenous norepinephrine and suggesting a denervation of the neuroeffector junction. Staining for tyrosine hydroxylase demonstrated sympathetic denervation, with neurons occupying less area and located further from the enlarged collateral at day 7. Inversely, MMP2 presence surrounding the enlarged collateral was greater at day 7, suggesting that denervation may be related to extracellular matrix degradation during arteriogenesis. Further investigation on vascular wall maturation and the functionality of enlarged collaterals holds promise for identifying novel therapeutic targets to enhance arteriogenesis in patients with PAD.

Evaluation of TurboHawk Plaque Rotation System in Treatment of Superficial Femoral Atherosclerosis

BACKGROUND To investigate the curative effect and utility of the TurboHawk plaque circumcision system in the treatment of patients with superficial femoral atherosclerosis (SFA). MATERIAL AND METHODS We retrospectively analyzed 60 cases of superficial femoral atherosclerotic stenosis and occlusion treated with the TurboHawk plaque circumcision system for endovascular ablation of the superficial femoral artery in the People's Hospital of Xinjiang Uygur Autonomous Region between January 2016 and December 2017. RESULTS The sample comprised of 50 male and 10 female patients with an average age of 65±4.5 years (range 47 to 70 years). This group of patients had varying degrees of limb ischemia, with disease duration ranging from 1 week to 3 years. The main symptoms included markedly cooler lower-extremity skin temperature, pale and cyanotic, intermittent claudication (10 cases), resting pain (31 cases), distal limb mild ischemic ulcer (14 cases), and tissue ischemic necrosis and gangrene (5 cases). All cases were in stages 3-6 of the Rutherford classification. Almost half (28 patients, 47%) had a significant improvement in their affected limbs and more than half (32 cases, 53%) had a moderate improvement in clinical symptoms after the intervention. After surgery, lumen stenosis decreased and ankle brachial index (ABI) increased significantly (P<0.05). CONCLUSIONS The TurboHawk plaque circumcision system is a feasible and effective method for the treatment of SFA with the advantages of less trauma and better safety, and shows a significant curative effect in a short period.

Disease-specific characteristics of vascular cell adhesion molecule-1 levels in patients with peripheral artery disease

Peripheral arterial disease (PAD) is one of the most common manifestations of systemic atherosclerosis. The prevalence of unrecognized PAD is high, leading to a lack of opportunity to detect subjects at a high risk for cardiovascular events. Inflammatory processes play an important role in the disease initiation as well as in the disease progression. Vascular cell adhesion molecule 1 (VCAM-1), a biomarker of endothelial dysfunction, appears to be an important mediator in inflammatory processes. Therefore, we hypothesized that in patients with PAD, circulating VCAM-1 might be elevated due to its function in mediating adhesion of immune cells to the vascular endothelium in the process of endothelial dysfunction and inflammation, and, therefore, applicable as a diagnostic biomarker. A total of 126 non-consecutive patients were enrolled in this study, of whom 51 patients had typical clinical manifestations of PAD and as controls 75 patients with no history of PAD or cardiovascular disease. All serum samples were obtained either during hospitalization or during out-patient visits and analyzed for VCAM-1 by the ELISA. Compared with controls, median levels of VCAM-1 were significantly elevated in patients suffering from PAD (953 vs. 1352 pg/ml; p < 0.001). Furthermore, VCAM-1 appeared to be highly discriminative for the detection of PAD (AUC = 0.76; CI 0.67-0.83). We could not observe dynamics related to increasing disease stages according to Rutherford classes in patients with apparent PAD. VCAM-1 was shown to be a potential discriminator and biomarker for the severity of systemic atherosclerosis. In a logistic regression analysis, VCAM-1 was robustly associated with the diagnosis of PAD, even after correction for clinically relevant cofounders (namely age, arterial hypertension, diabetes and LDL levels). Thusly, VCAM-1 might serve as a biomarker for PAD screening and detection.

Optimal medical management before lower extremity bypass for claudication in the veteran population

OBJECTIVE

Optimizing medical management through glucose control, smoking cessation, and drug therapy (ie, antiplatelet and statin agents) is recommended as first-line therapy for patients with claudication. The aims of this study were to determine how frequently veterans with claudication received optimal medical management (OMM) before undergoing elective open lower extremity bypass procedures nationwide and whether preoperative OMM was associated with improved surgical outcomes.

METHODS

We reviewed all patients within the Veterans Affairs (VA) Surgical Quality Improvement Program database who underwent elective open lower extremity bypass procedures for claudication at nationwide VA medical centers from 2005 until 2015. We defined OMM as a claudicant's having documentation of receiving all of the following within 12 months before surgery: prescriptions for antiplatelet, statin, and smoking cessation therapy (if a smoker) and monitoring of hemoglobin A_1c (if diabetic). Outcome measures included occurrence of any 30-day VA Surgical Quality Improvement Program complication, amputation-free survival, and 30-day and 1-year mortality. We used multivariate regression and Cox proportional hazards models incorporating inverse probability treatment weighting to analyze the effect of OMM on outcome measures after adjusting for patient-level confounding.

RESULTS

Among 10,271 lower extremity bypass procedures performed, 2265 (22%) were undertaken in claudicants with a median age of 63 years (interquartile range, 58-68 years). Of claudicants, 839 (37%) were diabetic, and 1333 (59%) patients smoked within 12 months before surgery. OMM was achieved in only 581 (26%) claudicants before they underwent surgery, although adherence to individual components was variable: antiplatelet, 55%; statin, 63%; smoking cessation, 58%; and hemoglobin A_1c monitoring, 92%. In risk-adjusted analyses, there were no statistically significant differences in complication rates, amputation-free survival, or mortality outcomes among patients who received OMM compared with non-OMM patients.

CONCLUSIONS

Only a quarter of veterans with claudication were documented as receiving OMM within the year before undergoing open lower extremity bypass across nationwide VA medical centers, highlighting the need for strategies to ensure that medical therapy is intensified before surgical revascularization. Nevertheless, our data showed that documentation of preoperative OMM did not lead to improved short- or long-term postoperative outcomes in these patients, suggesting that more objective measures of medical management are needed to ensure that peripheral arterial disease goals are achieved.

Analysis of novel cardiovascular biomarkers in patients with peripheral artery disease

BACKGROUND

Peripheral artery disease (PAD) is a common form of manifestation of atherosclerosis. PAD has a considerable impact on morbidity, hospitalization rates and health-care costs. Biomarkers have been introduced in many cardiovascular disease entities over the last years. However, an analysis on the correlation of biomarker levels and PAD is still lacking.

METHODS

A total of 106 patients were enrolled in this current study, 51 that were diagnosed with PAD and 55 with excluded coronary and peripheral artery disease as controls. During outpatient visits, plasma samples of all patients were obtained and analyzed for sST2 (hemodynamics and inflammation), galectin-3 (fibrosis and remodeling), GDF-15 (remodeling and inflammation), suPAR (inflammation), and fetuin-A (vascular calcification) by use of ELISA after informed consent.

RESULTS

Compared with controls, patients with PAD showed significantly higher levels of sST2 (5248 vs. 7503 pg/mL, P<0.001), suPAR (2267 vs. 2414 pg/mL, P=0.02), galectin-3 (2795 vs. 4494 pg/mL, P<0.001), and GDF-15 (549 vs. 767 pg/mL, P<0.001). Fetuin-A showed a trend towards lower levels in patients with PAD (117 vs. 100 ng/mL, P=0.119).

CONCLUSIONS

Circulating levels of sST2, suPAR, galectin-3, and GDF-15 were significantly elevated in PAD patients. In contrast, fetuin-A levels showed a decrease in PAD patients indicating increased vascular calcification. Thus, by incorporating different pathophysiological processes present in PAD, tested novel biomarkers facilitate a more precise diagnosis as well as a more accurate evaluation of disease severity and progression.