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.

Pancreas Transplantation for Type 2 Diabetes: A Systematic Review, Critical Gaps in the Literature, and a Path Forward.

Pancreas transplantation in patients with type 2 diabetes (T2D) remains relatively uncommon compared with pancreas transplantation in patients with type 1 diabetes (T1D); however, several studies have suggested similar outcomes between T2D and T1D, and the practice has become increasingly common. Despite this growing interest in pancreas transplantation in T2D, no study has systematically summarized the data to date. We systematically reviewed the literature on pancreas transplantation in T2D patients including patient and graft survival, glycemic control outcomes, and comparisons with outcomes in T2D kidney transplant alone and T1D pancreas transplant recipients. We searched biomedical databases from January 1, 2000, to January 14, 2021, and screened 3314 records, of which 22 full texts and 17 published abstracts met inclusion criteria. Full-text studies were predominantly single center (73%), whereas the remaining most often studied the Organ Procurement and Transplantation Network database. Methodological quality was mixed with frequent concern for selection bias and concern for inconsistent definitions of both T2D and pancreas graft survival across studies. Overall, studies generally reported favorable patient survival, graft survival, and glycemic control outcomes for pancreas transplantation in T2D and expressed a need to better characterize the T2D patients who would benefit most from pancreas transplantation. We suggest guidance for future studies, with the aim of supporting the safe and evidence-based treatment of end-stage T2D and judicious use of scarce resources.