The aim of the present study was to develop a standardized contrast-enhanced duplex ultrasound (CE-DUS) protocol to assess lower-extremity muscle perfusion before and after exercise and determine relationships of perfusion with clinical and functional measures. CE-DUS (EPIQ 5G, Philips) was used before and immediately after a 10-minute, standardized bout of treadmill walking to compare microvascular perfusion of the gastrocnemius muscle in older (55-82 years) peripheral arterial disease (PAD) patients (n=15, mean ± SEM ABI=0.78±0.04) and controls (n=13). Microvascular blood volume (MBV) and microvascular flow velocity (MFV) were measured at rest and immediately following treadmill exercise, and the Modified Physical Performance Test (MPPT) was used to assess mobility function. In the resting state (pre-exercise) MBV in PAD patients was not significantly different than normal controls (5.17±0.71 vs. 6.20±0.83 arbitrary units (AU) respectively; P=0.36); however, after exercise, MBV was ∼40% lower in PAD patients compared with normal controls (5.85±1.13 vs. 9.53±1.31 AU respectively; P=0.04). Conversely, MFV was ∼60% higher in PAD patients compared with normal controls after exercise (0.180±0.016 vs. 0.113±0.018 AU respectively; P=0.01). There was a significant between-group difference in the exercise-induced changes in both MBV and MFV (P≤0.05). Both basal and exercise MBV directly correlated with MPPT score in the PAD patients (r=0.56-0.62, P<0.05). This standardized protocol for exercise stress testing of the lower extremities quantifies calf muscle perfusion and elicits perfusion deficits in PAD patients. This technique objectively quantifies microvascular perfusion deficits that are related to reduced mobility function and could be used to assess therapeutic efficacy in PAD patients.

Major adverse cardiac events (MACEs) were common complications after endovascular aortic repair (EVAR) causing significant post-operative morbidity and mortality. The aim of the study was to evaluate the cardiac risk after elective EVAR for uncomplicated non infected infrarenal abdominal aortic aneurysm (iAAA) in a large multicenter cohort. This is a multicenter, retrospective, financially unsupported physician-initiated observational cohort study conducted by four academic tertiary referral hospitals from January 2018 to March 2021. Baseline, perioperative, and postoperative information of elective EVARs was evaluated. The primary outcome was the incidence of MACE after EVAR, which was defined as acute coronary syndrome, non-ST-elevation myocardial infarction, unstable angina pectoris, de novo atrial fibrillation, hospitalization for heart failure and revascularization as well as cardiovascular death. Secondary outcomes were one year overall survival (all-cause mortality) and freedom from aorta-related mortality. Comparative analysis was conducted between MACE and overall population and univariate and multivariate logistic regression analyses were used to analyse factors associated with the risk of MACE occurrence and early 1-year mortality. The study has enrolled 497 patients (35 females, 7%) with a mean age of 75.3±7.8 years. MACE rate was 6.4% (32/497, events/patients) and the majority of the events were recorded in the post-operative period (24/32, 75%, overall 24/497, 4.8%). One-year survival from all-cause mortality was 94% (95%CI 91-96) and MACEs population showed a significant lower survival estimation rate (Overall-MACEs, 95.8% [95%CI 93-97] - 67.9% [95%CI 47-82], log-rank 41.950, p= .0001). Freedom from aorta-related mortality was 99.3% (95%CI 98-100). The perioperative needing for red blood cells (RBC) transfusions was strongly related to MACEs occurrence (odds ratio [OR] 2.67, 95%CI 1.52-4.68, p= .001) and one-year mortality (hazard ratio [HR] 2.14, 95%CI 1.48-3.09, p= .0001). MACEs represent a common complication in the post-operative and early period after elective EVAR. Blood loss requiring RBC transfusions is associated with increased post-operative MACEs and early mortality, suggesting that all the efforts should be carried out to reduce the bleeding during and after elective interventions.