Limitations of Vascular Quality Initiative-derived models to predict the outcomes of intervention for infrapopliteal limb-threatening ischemia

Artificial Intelligence to Predict Quality-of-Life Outcomes for Vascular Intervention of the Leg

BACKGROUND

Artificial intelligence (AI) tools created to enhance decision-making may have a significant impact on treatment algorithms for peripheral arterial disease (PAD). A Markov-based AI model was developed to predict optimal therapy based on maximization of calculated quality of life (cQoL), a patient-centered system of assessment designed to report outcomes directly linked to health-related quality of life.

STUDY DESIGN

The AI model was prospectively interrogated immediately after individual interventions for PAD over a 12-year period to test predictive performance. Patient cQoL was determined at each patient follow-up visit.

RESULTS

A total of 1,143 consecutive patients were evaluated, with a median follow-up of 18 months. Observed mean annualized cQoL was higher than predicted by the model (0.85 ± 0.38 vs 0.79 ± 0.18, p < 0.0001). Of 5 potential clinical outcomes, the AI model correctly predicted final status in 71.3% of patients, with insignificant model performance deterioration over time (-0.15% per month, r = -0.49, p = 0.063). The chance of having the condition predicted by the model was 0.57 ± 0.32, compared with a theoretical maximum of 0.70 ± 0.19 (p < 0.0001, mean ratio 0.79). The AI model performed better in patients with claudication than limb-threatening ischemia (75.5% vs 63.6%, p = 0.014) but equally well for open or endovascular intervention (69.8% vs 70.5%, p = 0.70). Graft or artery patency and amputation-free survival were better for patients with claudication and those treated with endovascular techniques.

CONCLUSIONS

AI can successfully predict treatment for PAD that maximizes patient quality of life in most cases. Future application of AI incorporating better estimates of patient anatomic and physiological risk factors and refinement of model structure should further enhance performance.

Analysis of Lower Extremity Amputations from the SerbVasc Registry

BACKGROUND

Peripheral arterial disease (PAD) and diabetes are the major causes of lower extremity amputations (LEAs) worldwide. Morbidity and mortality in patients with LEAs are high with an associated significant burden on the global health system. The aim of this article is to report the overall morbidity and mortality rates after major and minor LEAs from the Serbian Vascular Registry (SerbVasc), with an analysis of predictive factors that influenced adverse outcomes.

MATERIALS AND METHODS

SerbVasc was created in 2019 as a part of the Vascunet collaboration that is aiming to include all vascular procedures from 21 hospitals in Serbia. Prevalence of diabetes among patients with LEAs, previous revascularization procedures, the degree and the type of foot infection and tissue loss, and overall morbidity and mortality rates were analyzed, with a special reference to mortality predictors.

RESULTS

In the period from January 2020 to December 2022, data on 702 patients with LEAs were extracted from the SerbVasc registry, mean age of 69.06±10.63 years. Major LEAs were performed in 59%, while minor LEAs in 41% of patients. Diabetes was seen in 65.1% of the patients, with 44% of them being on insulin therapy. Before LEA, only 20.3% of patients had previous peripheral revascularization. Soft tissue infection, irreversible acute ischemia, and Fontaine III and IV grade ischemia were the most common causes of above-the-knee amputations while diabetic foot was the most common cause of transphalangeal and toe amputations. The infection rate was 3.7%, the re-amputation rate was 5.7%, and the overall mortality rate was 6.9%, with intrahospital mortality in patients with above-the-knee amputation of 11.1%. The most significant intrahospital mortality predictors were age >65 years (p<0.001), chronic kidney disease (CKD) (p<0.001), ischemic heart disease (IHD) (p=0.001), previous myocardial revascularization (p=0.017), emergency type of admission (p<0.001), not using aspirin (p=0.041), using previous anticoagulation therapy (p=0.003), and postoperative complications (p<0.001).

CONCLUSIONS

The main predictors of increased mortality after LEAs from the SerbVasc registry are age >65 years, CKD, IHD, previous myocardial revascularization, emergency type of admission, not using aspirin, using previous anticoagulation therapy, and postoperative complications. Taking into account high mortality rates after LEAs and a small proportion of previous peripheral revascularization, the work should be done on early diagnosis and timely treatment of PAD hopefully leading to decreased number of LEAs and overall mortality.

CLINICAL IMPACT

Mortality after lower limb amputation from the SerbVasc register is high. A small number of previously revascularized patients is of particular clinical importance, bearing in mind that the main reasons for above-the-knee amputations were irreversible ischemia, Fontaine III and Fontaine IV grade ischemia. Lack of diagnostics procedures and late recognition of patients with PAD, led to subsequent threating limb ischemia and increased amputation rates. The work should be done on early diagnosis and timely treatment of PAD in Serbia, hopefully leading to an increased number of PAD procedures, decreased number of LEAs, and lower overall mortality.

Propensity-score-matched analysis of dual antiplatelet treatment and alternative antiplatelet regimens after transcarotid revascularizations

OBJECTIVE

Dual antiplatelet therapy (DAPT) continues to be the preferred medication regimen after the placement of a carotid stent using the transcarotid revascularization (TCAR) technique despite a dearth of quality data. Therefore, this investigation was performed to define the risks associated with antiplatelet choice.

METHODS

We queried all patients who underwent TCAR captured by the Vascular Quality Initiative from September 2016 to June 2022, to determine the association between antiplatelet choice and outcomes. Patients maintained on DAPT were compared with those receiving alternative regimens consisting of single antiplatelet, anticoagulation, or a combination of the two. A 1:1 propensity-score match was performed with respect to baseline comorbidities, functional status, anatomic/physiologic risk, medications, and intraoperative characteristics. In-hospital and 1-year outcomes were compared between the groups.

RESULTS

During the study period, 29,802 procedures were included in our study population, with 24,651 (82.7%) receiving DAPT and 5151 (17.3%) receiving an alternative antiplatelet regimen. A propensity-score match with respect to 29 variables generated 4876 unique pairs. Compared with patients on DAPT, in-hospital ipsilateral stroke was significantly higher in patients receiving alternative antiplatelet regimens (1.7% vs 1.1%, odds ratio [95% confidence interval]: 1.54 [1.10-2.16], P = .01), whereas no statistically significant difference was noted with respect to mortality (0.6% vs 0.5%, 1.35 [0.72-2.54], P = .35). A composite of stroke/death was also more likely in patients receiving an alternative regimen (2.4% vs 1.7%, 1.47 [1.12-1.93], P = .01). Immediate stent thrombosis (2.75 [1.16-6.51]) and a nonsignificant trend toward increased return to the operating room were more common in the alternative patients. Conversely, the incidence of perioperative myocardial infarction was lower in the alternative regimen group (0.4% vs 0.7%, 0.53 [0.31-0.90], P = .02). At 1 year after the procedure, we observed an increased risk of mortality (hazard ratio [95% confidence interval]: 1.34 [1.11-1.63], P < .01) but not stroke (0.52 [0.27-0.99], P = .06) in patients treated with an alternative medication regimen.

CONCLUSIONS

This propensity-score-matched analysis demonstrates an increased risk of in-hospital stroke and 1-year mortality after TCAR in patients treated with an alternative medication regimen instead of DAPT. Further studies are needed to elucidate the drivers of DAPT failure in patients undergoing TCAR to improve outcomes for carotid stenting patients.

Predictors of 30-Day Stroke and Death After Transcarotid Revascularization

INTRODUCTION

Much of the previous robust analyses of the results associated with transcarotid revascularization (TCAR) derives from industry-sponsored trials or the Vascular Quality Initiative (VQI). This investigation was performed to identify preoperative predictors of 30-day stroke and death using institutional databases.

METHODS

A retrospective analysis was performed of carotid revascularization databases created at two high-volume TCAR centers and maintained independently of the VQI carotid module between December 2015 and December 2021. The primary outcome of interest was a composite of perioperative (30-day) stroke and death. Univariate regression analyses, followed by multivariate regression analyses, were performed to identify potential predictors of adverse events.

RESULTS

During the study period, 750 TCAR procedures were performed at our combined health systems, resulting in 24 (3.2%) individuals who experienced either stroke and/or death in the perioperative period. Of these, we observed nine (1.2%) mortality events and 18 (2.4%) strokes. On univariate analysis, candidate protectors of stroke/death were found to be coronary artery disease (odds ratio [OR], 0.43; 95% confidence interval [CI], 0.18-1.01; P = 0.05) and protamine reversal (0.51; 0.21-1.21; P = 0.15). Candidate predictors of the primary outcome were anticoagulant usage (3.03; 1.26-7.24; P = 0.01), postprocedural debris in the filter (2.30; 0.97-5.43; P = 0.06), symptomatic carotid lesion (2.03; 0.90-4.50), and cardiac arrhythmia (1.98; 0.80-4.03; P = 0.14). On multivariate analysis, two predictors remained, cardiac arrhythmia (4.21; 1.10-16.16; P = 0.04) and symptomatic carotid lesion (14.49; 1.80-116.94; P = 0.01).

CONCLUSIONS

A symptomatic carotid lesion, and to a lesser extent cardiac arrhythmia, are strong predictors of 30-day stroke/death after TCAR. Surgeons should be cognizant of the increased risk of adverse events in the perioperative period in these patients.

External validation of the Vascular Quality Initiative prediction model for survival in no-option chronic limb-threatening ischemia patients

OBJECTIVE

Chronic limb-threatening ischemia (CLTI) is associated with high morbidity and mortality rates. More than 50% of all CLTI patients die within 5 years after presentation. Patient-specific survival prediction is critical for informing treatment strategies, even for those without a clear option for revascularization. We validated a survival prediction model, developed in a revascularized Vascular Quality Initiative (VQI) cohort, in a Western European no-option CLTI cohort.

METHODS

The VQI survival prediction model was applied to the validation cohort (N = 150) to compare estimated mortality and observed mortality at 2 years after baseline. Performance of the VQI model was tested by evaluating discrimination using the receiver operating characteristic area under the curve and calibration using the Hosmer-Lemeshow goodness-of-fit test.

RESULTS

The 2-year survival rate was 79% in the validation cohort compared with 83% in the VQI cohort. Baseline characteristics were significantly different for 13 of 17 variables. The C statistic was 0.86 (95% confidence interval, 0.78-0.95), which indicates good discrimination. The Hosmer-Lemeshow goodness-of-fit test had a P value of .30, which indicates good fit.

CONCLUSIONS

This is the first external validation of the VQI survival prediction model. The good model performance suggests that this model can be used in different CLTI populations, including no-option CLTI, and underlines its contributory role in this challenging population.