Discrete Event Simulation Model for Cost-Effectiveness Evaluation of Screening for Asymptomatic Patients with Lower Extremity Arterial Disease

Lower limb ischemic disease (LEAD) affects a significant portion of the population, with most patients being asymptomatic. Patient screening is necessary because LEAD patients have an increased risk of occurrence of other cardiovascular events and manifestations of disease, in terms of leg symptoms such as intermittent claudication, critical limb ischemia, or amputation. The aim of this work was to evaluate the cost-effectiveness of screening using ABI diagnostics in asymptomatic patients and its impact on limb symptoms associated with LEAD. A discrete event simulation model was created to capture lifetime costs and effects. Costs were calculated from the perspective of the health care payer, and the effects were calculated as QALYs. A cost-effectiveness analysis was performed to compare ABI screening examination and the situation without such screening. A probabilistic sensitivity analysis and scenario analysis were carried out to evaluate the robustness of the results. In the basic setting, the screening intervention was a more expensive intervention, at a cost of CZK 174,010, compared to CZK 70,177 for the strategy without screening. The benefits of screening were estimated at 14.73 QALYs, with 14.46 QALYs without screening. The final ICER value of CZK 389,738 per QALY is below the willingness to pay threshold. Likewise, the results of the probabilistic sensitivity analysis and of the scenario analysis were below the threshold of willingness to pay, thus confirming the robustness of the results. In conclusion, ABI screening appears to be a cost-effective strategy for asymptomatic patients aged 50 years when compared to the no-screening option.

The Global Limb Anatomic Staging System is associated with outcomes of infrainguinal revascularization in chronic limb threatening ischemia

OBJECTIVE

The Global Limb Anatomic Staging System (GLASS) has been proposed to facilitate clinical decision-making regarding revascularization for chronic limb threatening ischemia (CLTI). The purpose of the present study was to define its relationship to the treatment outcomes in CLTI.

METHODS

Consecutive patients who had undergone peripheral angiography for rest pain or tissue loss from January 2017 to July 2019 at a tertiary referral center with a dedicated limb preservation program were reviewed. Subjects with significant aortoiliac disease, previous infrainguinal stenting or functioning bypass grafts, or GLASS stage 0 were excluded. The GLASS score was assigned from the preintervention angiography findings, and the treating surgeon determined the primary infrapopliteal target artery pathway for the limb at risk. The demographic data, procedural details, and clinical outcomes were analyzed.

RESULTS

The study cohort included 167 patients and 194 limbs, of which 175 of 194 limbs (90%) had presented with tissue loss and 149 of 182 limbs (83%) with WIfI (Wound, Ischemia and foot Infection) stage 3 or 4. The GLASS stage was GLASS 1 in 14%, GLASS 2 in 18%, and GLASS 3 in 68%. GLASS 3 anatomy was present in 85% of 52 limbs treated by bypass and 55% of 108 limbs treated by endovascular intervention (EVI; P < .001). Revascularization was not performed in 34 limbs, most of which were GLASS 3 (85%). Immediate technical failure for EVI (ie, failure to establish target artery pathway) occurred exclusively in the setting of GLASS 3 anatomy (n = 13; 22%). After a median follow-up of 10 months, limb-based patency after EVI was significantly lower in GLASS 3 than in GLASS 1 or 2 limbs (42% vs 59%; P = .018). GLASS 3 was associated with reduced major adverse limb events-free survival in both the EVI group (P = .002) and the overall revascularized cohort (P = .001). GLASS 3 was also associated with significantly reduced overall survival, amputation-free survival, and reintervention-free survival. In a Cox proportional hazards model, GLASS 3 (hazard ratio, 2.35; 95% confidence interval, 1.30-4.24; P = .005) and WIfI wound grade 3 (hazard ratio, 2.64; 95% confidence interval, 1.26-5.53; P = .010) were independent predictors of reduced major adverse limb events-free survival after revascularization.

CONCLUSIONS

GLASS stage 3 was strongly associated with major adverse clinical outcomes after revascularization in patients with CLTI.

In Situ Vein Bypass Is Superior to Endovascular Treatment of Femoropopliteal Lesions in Chronic Limb-Threatening Ischemia

BACKGROUND

The objective of the study was to compare bypass surgery and endovascular revascularization of the femoropopliteal segment in patients with peripheral arterial disease and critical limb-threatening ischemia (CLTI).

METHODS

This is a single-center study including patients undergoing first-time lower extremity intervention with peripheral bypass surgery or percutaneous transluminal angioplasty with or without stenting (PTA/S) of the femoropopliteal segment because of CLTI from 2011 to 2015. Based on prospective entered data from the Danish Vascular Registry, the primary end points were amputation-free survival, overall mortality, and reinterventions.

RESULTS

A total of 679 patients with CLTI were included of which 35% (n = 239) were treated with PTA/S, 54% (n = 363) with vein bypass, and 11% (n = 77) with synthetic bypass. After 3 years, amputation-free survival was significantly better with a vein bypass (41.8% [95% CI: 35-48.4]) than both PTA/S (29.7% (95% CI: 22.7-37)) and synthetic bypass (31.7% [95% CI: 19-45.1]). Overall, the endovascular-treated patients faced more than 50% increased risk of major amputation or death than that of a vein bypass, after adjusting for comorbidity and Trans-Atlantic Inter-Society Consensus (TASC) classification (HR: 1.56 [95% CI: 1.21-2.05]). As expected, postoperative complications, length of hospital stay, and reinterventions were more frequent in the bypass groups.

CONCLUSIONS

In this nonrandomized study, autologous vein bypass was superior to both PTA/S and synthetic bypass in regard to amputation-free survival and overall mortality. Despite the increased frequency of surgical complications, a vein bypass appears justified in both shorter (TASC B-C) and longer (TASC D) femoropopliteal lesions.

Viabahn Stent Graft for the Endovascular Treatment of Occlusive Lesions in the Femoropopliteal Artery: A Retrospective Cohort Study with 4-Year Follow-Up

BACKGROUND

The polytetrafluoroethylene-covered Viabahn stent may be effective for the endovascular treatment of patients with femoropopliteal artery occlusive lesions. However, the long-term efficacy of Viabahn stent remains unclear. The aim of the study is to evaluate the long-term patency of Viabahn stent grafts in patients with occlusive lesions in the femoropopliteal artery.

METHODS

Consecutive patients with occlusive lesions in the femoropopliteal artery who had been treated with Viabahn stent grafts during the period from June 2013 to December 2016 at our center were retrospectively included. Accumulative incidences of primary patency and secondary patency were estimated by Kaplan-Meier survival analysis, and the predictors of primary patency were evaluated by Cox regression analysis.

RESULTS

A total of 66 patients underwent successful endovascular treatment and were included in the study. Endovascular treatment with a Viabahn stent was associated with a complication rate of 9.1% and a 30-day mortality rate of 1.5%. Sixty-one patients were followed for a mean duration of 29.5 months. The 1-year, 2-year, 3-year, and 4-year primary patency rates were 81.7%, 74.7%, 67.6%, and 58.9%, respectively. The secondary patency rates were 94.9%, 92.9%, 90.1%, and 90.1%, respectively. The overall major amputation rate was 5.0%. The results of multivariate Cox regression analyses showed that stent location was the only independent predictor of primary patency (P = 0.001). Implantation of a Viabahn stent above the knee, compared with implantation below the knee, was associated with a higher rate of primary patency.

CONCLUSIONS

The Viabahn stent graft is associated with a satisfactory rate of long-term patency for the endovascular treatment of occlusive lesions in the femoropopliteal artery, especially for those located above the knee.

Comparison of Bypass and Endovascular Intervention for Popliteal Occlusion with the Involvement of Trifurcation for Critical Limb Ischemia

BACKGROUND

The aim of this study is to analyze the technical aspects and outcomes of the treatment of occlusion of the popliteal artery with the involvement of the trifurcation treated with a bypass (open) and endovascular (endo) approach.

METHODS

Overall, 108 consecutive procedures were enrolled retrospectively. Patients were evaluated in 2 groups: the endo group (65 patients) and the open group (43 patients). Primary outcome were MALE (major adverse limb events), amputation-free survival, and early mortality (until 30 days). Secondary outcome was overall survival in 3 years. Inclusion criteria were Rutherford 4 and 5 and occlusion of the popliteal artery with the involvement of trifurcation and, at least, 1 infrapopliteal artery of runoff.

RESULTS

Technical success was achieved in 100% of patients in the open and 96.9% of patients in the endo group. Freedom from MALE was 73.5% and 68.5% for 1 and 3 years respectively for the endo group, and 84.3% and 77.2% respectively for the open group (P = 0.413). Considering the total number of major reinterventions executed until 3 years, the reinterventions was statistically more performed in the endo compared to the open group (P = 0.0459). Amputation-free survival for the endo group in 30 days, 1 year, and 3 years was 93.7%, 79.3%, and 66.0%, respectively, and the amputation-free survival for the open group was 88.4%, 77.4%, and 64.3% (P = 0.726). Early mortality was 9.3% for the open group and 1.5% for the endo group (P = 0.060). In 3 years, the overall survival was 75.1% in the open group and 84.3% in the endo group.

CONCLUSIONS

In 3 years, follow-up endovascular treatment of occlusion of the popliteal artery with the involvement of the trifurcation has similar time freedom from MALE compared to open approach. Overall and amputation-free survival was not different between the groups besides more reinterventions in patients who underwent endovascular approach.