Risk Models and Scores in Patients with Peripheral Artery Disease and Chronic Limb-threatening Ischemia: A Comprehensive Review

Modification of Peripheral Blood Flow and Angiogenesis by CO2 Water-Bath Therapy in Diabetic Skeletal Muscle with or without Ischemia

Previously, it was shown that both blood flow and angiogenesis in the ischemic hind limb of diabetic rats were increased upon CO2 treatment for 4 weeks. In the present study, we have compared the effects of 6 weeks CO2 therapy in diabetic rats with or without peripheral ischemia. Diabetes was induced in rats by a tail vein injection of streptozotocin (65 mg/kg body weight), whereas peripheral ischemia was produced by occluding the femoral artery at 2 weeks of inducing diabetes. Both diabetic and diabetic-ischemic animals were treated with or without CO2 water-bath at 37 °C for 6 weeks (30 min/day; 5 days/week) starting at 2 weeks, after the induction of ischemia. CO2 treatment did not affect heart rate and R-R interval as well as plasma levels of creatine kinase, glucose, cholesterol, triglycerides and high density lipoproteins. Unlike the levels of plasma Ox-LDL, MDA and TNF-α, the levels of NO in diabetic group were increased by CO2 water-bath treatment. On the other hand, the levels of plasma Ox-LDL and MDA were decreased whereas that of NO was increased without any changes in TNF-α level in diabetic-ischemic animals upon CO2 therapy. Treatment of diabetic animals with CO2 increased peak, mean and minimal blood flow by 20, 49 and 43% whereas these values were increased by 53, 26 and 80% in the diabetic-ischemic group by CO2 therapy, respectively. Blood vessel count in diabetic and diabetic-ischemic skeletal muscles was increased by 73 and 136% by CO2 therapy, respectively. These data indicate that peripheral ischemia augmented the increase in blood flow and development of angiogenesis in diabetic skeletal muscle upon CO2 therapy. It is suggested that greater beneficial effects of CO2 therapy in diabetic-ischemic animals in comparison to diabetic group may be a consequence of difference of changes in the redox-sensitive signal transduction mechanisms.

Application of machine learning algorithms in electronic medical records to predict amputation-free survival after first revascularization in patients with peripheral artery disease

BACKGROUND

This study aimed to apply eight machine learning algorithms to develop the optimal model to predict amputation-free survival (AFS) after first revascularization in patients with peripheral artery disease (PAD).

METHODS

Among 2130 patients from 2011 to 2020, 1260 patients who underwent revascularization were randomly assigned to training set and validation set in an 8:2 ratio. 67 clinical parameters were analyzed by lasso regression analysis. Logistic regression, gradient boosting machine, random forest, decision tree, eXtreme gradient boosting, neural network, Cox regression, and random survival forest (RSF) were applied to develop prediction models. The optimal model was compared with GermanVasc score in testing set comprising patients from 2010.

RESULTS

The postoperative 1/3/5-year AFS were 90%, 79.4%, and 74.1%. Age (HR:1.035, 95%CI: 1.015-1.056), atrial fibrillation (HR:2.257, 95%CI: 1.193-4.271), cardiac ejection fraction (HR:0.064, 95%CI: 0.009-0.413), Rutherford grade ≥ 5 (HR:1.899, 95%CI: 1.296-2.782), creatinine (HR:1.03, 95%CI: 1.02-1.04), surgery duration (HR:1.03, 95%CI: 1.01-1.05), and fibrinogen (HR:1.292, 95%CI: 1.098-1.521) were independent risk factors. The optimal model was developed by RSF algorithm, with 1/3/5-year AUCs in training set of 0.866 (95% CI:0.819-0.912), 0.854 (95% CI:0.811-0.896), 0.844 (95% CI:0.793-0.894), in validation set of 0.741 (95% CI:0.580-0.902), 0.768 (95% CI:0.654-0.882), 0.836 (95% CI:0.719-0.953), and in testing set of 0.821 (95%CI: 0.711-0.931), 0.802 (95%CI: 0.684-0.919), 0.798 (95%CI: 0.657-0.939). The c-index of the model outperformed GermanVasc Score (0.788 vs 0.730). A dynamic nomogram was published on shinyapp (https://wyy2023.shinyapps.io/amputation/).

CONCLUSION

The optimal prediction model for AFS after first revascularization in patients with PAD was developed by RSF algorithm, which exhibited outstanding prediction performance.

Health-related quality of life after a one-year follow-up of patients undergoing endovascular leg revascularization

BACKGROUND

Lower limb revascularization not only improves walking distance, but also disease-specific and general health-related quality of life (HRQoL). Therefore, we analyzed changes in HRQoL after endovascular leg revascularization in patients with chronic lower limb ischemia during a one-year follow-up.

PATIENTS AND METHODS

The WHOQOL-BREF questionnaire was completed by 50 patients with intermittent claudication (IC) and 50 patients with chronic limb-threatening ischemia (CLTI) who underwent endovascular revascularization with a stent implantation, as well as 40 patients with IC not requiring endovascular intervention who received medical management only. The survey was completed before and then 3 and 12 months after an intervention.

RESULTS

Patients with CLTI before endovascular intervention had the lowest HRQoL in the somatic, psychological, social, and environmental domains. After endovascular revascularization, these patients achieved the greatest improvement in HRQoL. Scores in the HRQoL domains correlated with Rutherford class, ankle-brachial index, and walking distance. The initial score in the somatic domain predicted the risk of target lesion revascularization (TLR) during the one-year follow-up.

CONCLUSIONS

Endovascular leg revascularization improved patients' functioning, not only in the physical, but also in the psychological, environmental and social domains of HRQoL. A higher score in the somatic domain of HRQoL before and at 3 months after an intervention predicted the risk of TLR during the one-year follow-up. It is recommended that scores for general HRQoL domains are added to the standard measures of the direct outcome of leg revascularization due to their one-year prognostic value.

A Systematic Review and Meta-analysis on the Efficacy and Safety of Direct Oral Anticoagulants in Patients with Peripheral Artery Disease

BACKGROUND-OBJECTIVE

PAD is a significant cause of morbidity and mortality affecting over 200 million people worldwide. Current guidelines recommend at least a single antiplatelet or anticoagulant agent in symptomatic PAD and lifelong antithrombotic treatment after a revascularization procedure. The aim of this systematic review and meta-analysis was to investigate the efficacy and safety of direct oral anticoagulants (DOACs) in patients with peripheral artery disease (PAD). PAD is a significant cause of morbidity and mortality affecting over 200 million people worldwide.

METHODS

The present systematic review and meta-analysis was performed according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines. Risk ratios (RR) were calculated using the random effects model.

RESULTS

Overall, ten studies were included in this systematic review and meta-analysis. In four studies, 14,257 patients with PAD were enrolled and they were assigned to receive either aspirin (ASA)+/- clopidogrel (N=5,894) or DOAC+/- anti-platelet (e.g., ASA, clopidogrel) (N=8,363). Non DOAC users were found to have higher reintervention rates (RR 1.12; 95% CI 1.01-1.24; p=0.025) compared to DOAC users. No statistically significant difference was observed between the two groups, in terms of major bleeding (RR 0.78; 95% CI 0.50-1.23; p=0.285), all-cause mortality (RR 0.98; 95% CI: 0.83-1.16; p=0.818) and cardiovascular mortality (RR: 0.99; 95% CI: 0.73-1.333; p=0.946) mortality. In addition, two real-world studies comparing DOAC with warfarin showed decreased rates of major cardiovascular events in the DOAC group.

CONCLUSIONS

DOAC use alone or combined with an anti-platelet agent could be associated with lower re-intervention rates, without increasing the risk for adverse bleeding events. However, this study failed to detect any difference in terms of all-cause mortality, MACEs and MALEs between DOAC users and DOAC naïve patients. Future studies are needed to better determine the efficacy and safety of DOACs in patients with PAD.