Limb-based patency as a measure of effective revascularization for chronic limb-threatening ischemia.

OBJECTIVE: In 2019, the Global Vascular Guidelines on chronic limb-threatening ischemia (CLTI) introduced the concept of limb-based patency (LBP) defined as maintained patency of a target artery pathway after intervention. The purpose of this study was to investigate the relationship between LBP and major adverse limb events (MALE) after infrainguinal revascularization for CLTI. METHODS: Consecutive patients undergoing revascularization for CLTI between 2016 and 2019 at a single tertiary institution with a dedicated limb preservation team were included. Subjects with aortoiliac disease, prior infrainguinal stents, or existing bypass grafts were excluded. Demographics, Global Limb Anatomic Staging System scores, Wound, Ischemia, foot Infection (WIfI) stages, revascularization details, and limb-specific outcomes were reviewed. LBP was defined by the absence of reintervention, occlusion, critical stenosis (>70%), or hemodynamic compromise with ongoing symptoms of CLTI. MALE included thrombectomy or thrombolysis, new bypass, open surgical graft revision and/or major amputation. RESULTS: We analyzed 184 unique limbs in 163 patients. This cohort was composed of 66.9% male patients with a mean age of 72 years. Baseline characteristics included diabetes (66%), tissue loss (91%), and advanced WIfI stages (30% stage 3, 51% stage 4). Global Limb Anatomic Staging System stage 3 anatomic patterns were common (n = 119 [65%]). Sixty limbs were treated with open bypass (65% involving tibial targets) and 124 underwent endovascular intervention (70% including infrapopliteal targets). The 12-month freedom from MALE and loss of LBP were 74.0% ± 3.7% and 48.6% ± 4.2%, respectively. Diabetes (hazard ratio [HR], 2.56; 95% confidence interval [CI], 1.13-5.83; P = .025) and loss of LBP (HR, 4.12; 95% CI, 1.96-8.64; P < .001) were independent predictors of MALE in a Cox proportional hazard model. Loss of LBP was the sole independent predictor of major limb amputation after revascularization (HR, 4.97; 95% CI, 1.89-13.09; P = .001). Loss of LBP impacted both intermediate-risk limbs (HR, 2.85; 95% CI, 1.02-7.97; P = .047 in WIfI stages 1-3) and high-risk limbs (HR, 3.99; 95% CI, 1.32-12.11; P = .014 in WIfI stage 4). However, the loss of LBP had the greatest impact on patients presenting with WIfI stage 4 disease (31% vs 8% major limb amputation at 12 months in limbs without vs with maintained LBP). CONCLUSIONS: The anatomic durability of revascularization, as measured by LBP, is a key determinant of treatment outcomes in CLTI regardless of the initial mode of intervention undertaken. Loss of LBP is most detrimental in patients presenting with advanced limb threat (WIfI stage 4).

Applicability of the Vascular Quality Initiative mortality prediction model for infrainguinal revascularization in a tertiary limb preservation center population.

OBJECTIVE: Patients undergoing revascularization for chronic limb-threatening ischemia (CLTI) are at elevated risk for both mortality and limb loss. To facilitate therapeutic decision-making, a mortality prediction model derived from the Vascular Quality Initiative (VQI) database has stratified patients into low, medium, and high risk, defined by 30-day mortality estimates of ≤3%, 3%-5%, or >5% and 2-year mortality estimates of ≤30%, 30%-50%, or ≥50%, respectively. The purpose of this study was to compare expected mortality risk derived from this model with observed outcomes in a tertiary center. METHODS: Consecutive patients treated at a single center between 2016 and 2019 were analyzed. Baseline demographics, approach, and mortality events were reviewed. Observed mortality was obtained using life-table methods and compared using a log-rank test with the expected mortality risk that was calculated using the VQI model. RESULTS: This study cohort consisted of 195 revascularization procedures in 169 unique patients stratified into 128 (66%) low-, 50 (26%) medium-, and 17 (8%) high-risk cases based on the VQI model. Ninety percent of revascularizations were performed for tissue loss. Compared with the VQI population, comorbidities were prevalent and included unstable angina or myocardial infarction within 6 months (6% vs 2.4% in VQI; P < .001), congestive heart failure (30% vs 23%; P < .001), and dialysis dependence (14% vs 0.9%; P < .001). Patients were also older (31% vs 21% ≥80 years old; P < .001) and more likely to be frail (45% vs 64% independent; P < .001). High-risk patients were more prevalent in the endovascular group (11% of 132 endovascular interventions vs 3% of 63 bypasses; P = .056). Thirty-day observed mortality exceeded expected VQI prediction model mortality in all groups, although was not statistically significant. The VQI model adequately stratified the studied population into risk groups (P < .001). Low-risk patients with CLTI (65% of the overall cohort) experienced 2-year mortality of 18.9%. However, observed mortality rates for medium- and high-risk VQI strata were similar. After a median follow-up of 28 months, medium-risk patients incurred a significantly higher mortality than predicted (53.5% ± 2.1% vs 36.8% ± 1.1%; P = .016). CONCLUSIONS: The VQI mortality prediction model discriminates mortality risk after limb revascularization in CLTI, accurately identifying a majority subgroup of patients who are suitable for either open or endovascular intervention. However, it may underestimate mortality in a tertiary referral population with high comorbidity burden and was not well calibrated for the medium-risk group. It may be more appropriate to dichotomize patients with CLTI who are candidates for limb salvage into an average-risk and high-risk group.

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.