Critical analysis and limitations of resting ankle-brachial index in the diagnosis of symptomatic peripheral arterial disease patients and the role of diabetes mellitus and chronic kidney disease.

BACKGROUND: The ankle-brachial index (ABI) may underestimate the severity of peripheral arterial disease (PAD) in patients with noncompressible vessels. This study analyzed limitations of the ABI and toe-brachial index (TBI), if done alone, in patients with symptomatic PAD, diagnosed by duplex ultrasound (DUS) examination, particularly in patients with diabetes and chronic kidney disease (CKD). METHODS: This is a retrospective review of prospectively collected data. All patients underwent resting ABIs, TBI, and/or DUS. An ABIs of 0.90 or less in either leg was considered abnormal, and the term inconclusive ABIs (noncompressibility) was used if the ABI was 1.3 or greater. The sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy (OA) of ABIs in detecting 50% or greater stenosis of any arterial segment based on DUS were determined. A TBI of less than 0.7 was considered abnormal. RESULTS: We included 2226 ABIs and 1383 DUS examinations: 46% of patients had diabetes, 16% had CKD, and 39% had coronary artery disease. Fifty-three percent of the ABIs were normal, 34% were abnormal, and 13% were inconclusive. For patients with limb-threatening ischemia, 40% had normal ABIs, 40% abnormal ABIs, and 20% were inconclusive. The sensitivity and OA for ABIs in detecting 50% or greater stenosis in the whole series were 57% (95% confidence interval [CI], 53.7-61.2) and 74% (95% CI, 71.9-76.6); for diabetics 51% (95% CI, 46.1-56.3) and 66% (95% CI, 62.3-69.8); nondiabetics 66% (95% CI, 59.9-70.9) and 81% (95% CI, 78.2-83.9). For patients with CKD, the sensitivity and OA for ABIs in detecting 50% or greater stenosis was 43% (95% CI, 34.3-52.7) and 67% (95% CI, 60.2-73.0) versus patients with no CKD 60% (95% CI, 56.3-64.6) and 76% (95% CI, 73.1-78.1). If patients with inconclusive ABIs were excluded, these values were 69% (95% CI, 65.2-72.9) and 80% (95% CI, 77.2-81.9) in the whole series; 67% (95% CI, 61.6-72.7) and 75% (95% CI, 70.5-78.4) for diabetics; and 63% (95% CI, 51.3-73.0) and 78% (95% CI, 70.6-83.9) for patients with CKD. Thirty-three percent of TBIs were normal and 67% were abnormal. The sensitivity and OA for abnormal TBI in detecting 50% or greater stenosis were 85% (95% CI, 78.9-90.0) and 75% (95% CI, 70.1-80.2) in the whole series; 84% (95% CI, 76.0-90.3) and 74% (95% CI, 67.1-80.2) for diabetics; and 77% (95% CI, 61.4-88.2) and 72% (95% CI, 59.9-82.3) for patients with CKD. For those with inconclusive ABIs, these values for TBI were 75% and 69%. CONCLUSIONS: Of symptomatic patients with PAD with 50% or greater stenosis on DUS examination, 43% had normal/inconclusive resting ABIs (49% in diabetics and 57% in CKD). TBI may help in patients with inconclusive ABIs. These patients should undergo further imaging to determine proper treatment.

Anatomical and technical predictors of perioperative clinical outcomes after carotid artery stenting.

BACKGROUND: A few other studies have reported the effects of anatomical and technical factors on clinical outcomes of carotid artery stenting (CAS). This study analyzed the effect of these factors on perioperative stroke/myocardial infarction/death after CAS. METHODS: This was a retrospective analysis of prospectively collected data of 409 of 456 patients who underwent CAS during the study period. A logistic regression analysis was used to determine the effects of anatomical and technical factors on perioperative stroke, death, and myocardial infarction (major adverse events [MAEs]). RESULTS: The MAE rate for the entire series was 4.7% (19 of 409), and the stroke rate was 2.2% (9 of 409). The stroke rate for asymptomatic patients was 0.46% (1 of 218; P = .01). The MAE rates for patients with transient ischemic attack (TIA) were 7% (11 of 158) vs 3.2% (8 of 251) for other indications (P = .077). The stroke rates for heavily calcified lesions were 6.3% (3 of 48) vs 1.2% (4 of 332) for mildly calcified/noncalcified lesions (P = .046). Differences in stroke and MAE rates regarding other anatomical features were not significant. The stroke rate for patients with percutaneous transluminal angioplasty (PTA) before embolic protection device (EPD) insertion was 9.1% (2 of 22) vs 1.8% (7 of 387) for patients without (P = .07) and 2.6% (9 of 341) for patients with poststenting PTA vs 0% (0 of 68) for patients without. The MAE rate for patients with poststenting PTA was 5.6% (19 of 341) vs 0% (0 of 68) for patients without (P = .0536). The MAE rate for patients with the ACCUNET (Abbott, Abbott Park, Ill) EPD was 1.9% (3 of 158) vs 6.7% (16 of 240) for others (P = .029). The differences between stroke and MAE rates for other technical features were not significant. A regression analysis showed that the odds ratio for stroke was 0.1 (P = .031) for asymptomatic indications, 13.7 (P = .014) for TIA indications, 6.1 (P = .0303) for PTA performed before EPD insertion, 1.7 for PTA performed before stenting, and 5.4 (P = .0315) for heavily calcified lesions. The MAE odds ratio was 0.46 (P = .0858) for asymptomatic indications, 2.1 for PTAs performed before EPD insertion, 2.2 for poststent PTAs, and 2.2 (P = .1888) for heavily calcified lesions. A multivariate analysis showed that patients with TIA had an odds ratio of stroke of 11.05 (P = .029). Patients with PTAs performed before EPD insertion had an OR of 6.15 (P = .062). Patients with heavily calcified lesions had an odds ratio of stroke of 4.25 (P = .0871). The MAE odds ratio for ACCUNET vs others was 0.27 (P = .0389). CONCLUSIONS: Calcific lesions and PTA before EPD insertion or after stenting were associated with higher stroke or MAE rates, or both. The ACCUNET EPD was associated with lower MAE rates. There was no correlation between other anatomical/technical variables and CAS outcome.

Clinical Outcome of Carotid Artery Stenting According to Provider Specialty and Volume.

BACKGROUND: Several studies have demonstrated better outcomes for carotid endarterectomy with high-volume hospitals and providers. However, only a few studies have reported on the impact of operator specialty/volume on the perioperative outcome of carotid artery stenting (CAS). This study will analyze the correlation of CAS outcomes and provider specialty and volume. METHODS: Prospectively collected data of CAS procedures done at our institution during a 10-year period were analyzed. Major adverse events (MAEs; 30-day stroke, myocardial infarction, and death) were compared according to provider specialty (vascular surgeons [VSs], interventional cardiologists [ICs], interventional radiologists [IRs], interventional vascular medicine [IVM]), and volume (≥5 CAS/year vs. <5 CAS/year). RESULTS: Four hundred fourteen CAS procedures (44% for symptomatic indications) were analyzed. Demographics/clinical characteristics were somewhat similar between specialties. MAE rates were not significantly different between various specialties: 3.1% for IC, 6.3% for VS, 7.1% for IR, 6.7% for IVM (P = 0.3121; 6.3% for VS and 3.8% for others combined, P = 0.2469). When physicians with <5 CAS/year were excluded: the MAE rates were 3.1% for IC, 4.7% for VS, and 6.7% for IVM (P = 0.5633). When VS alone were compared with others, and physicians with <5 CAS/year were excluded, the MAE rates were 4.7% for VS vs. 3.6% for non-VS (P = 0.5958). The MAE rates for low-volume providers, regardless of their specialty, were 9.5% vs. 4% for high-volume providers (P = 0.1002). Logistic regression analysis showed that the odds ratio of MAE was 0.4 (0.15-1.1, P = 0.0674) for high-volume providers, while the odds ratio for VS was 1.3 (0.45-3.954, P = 0.5969). CONCLUSIONS: Perioperative MAE rates for CAS were similar between various providers, regardless of specialties, particularly for vascular surgeons with similar volume to nonvascular surgeons. Low-volume providers had higher MAE rates.

Compliance of postendovascular aortic aneurysm repair imaging surveillance.

OBJECTIVE: Imaging surveillance after endovascular aortic aneurysm repair (EVAR) is critical. In this study we analyzed compliance with imaging surveillance after EVAR and its effect on clinical outcomes. METHODS: Retrospective analysis of prospectively collected data of 565 EVAR patients (August 2001-November 2013), who were followed using duplex ultrasound and/or computed tomography angiography. Patients were considered noncompliant (NC) if they did not have any follow-up imaging for 2 years and/or missed their first post-EVAR imaging over 6 months. A Kaplan-Meier analysis was used to compare compliance rates in EVAR patients with hostile neck (HN) vs favorable neck (FN) anatomy (according to instructions for use). A multivariate analysis was also done to correlate compliance and comorbidities. RESULTS: Forty-three percent were compliant (7% had no follow-up imaging) and 57% were NC. The mean follow-up for compliant patients was 25.4 months (0-119 months) vs 31.4 months for NC (0-140 months). The mean number of imaging was 3.5 for compliant vs 2.6 for NC (P < .0001). Sixty-four percent were NC for HN patients vs 50% for FN patients (P = .0007). The rates of compliance at 1, 2, 3, 4, and 5 years for all patients were 78%, 63%, 55%, 45%, and 32%; and 84%, 68%, 61%, 54%, and 40% for FN patients; and 73%, 57%, 48%, 37%, and 25% for HN patients (P = .009). The NC rate for patients with late endoleak and/or sac expansion was 58% vs 54% for patients with no endoleak (P = .51). The NC rate for patients with late reintervention was 70% vs 53% for patients with no reintervention (P = .1254). Univariate and multivariate analyses showed that patients with peripheral arterial disease had an odds ratio of 1.9 (P = .0331), patients with carotid disease had an odds ratio of 2 (P = .0305), and HN patients had an odds ratio of 1.8 (P = .0007) for NC. Age and residential locations were not factors in compliance. CONCLUSIONS: Overall, compliance of imaging surveillance after EVAR was low, particularly in HN EVAR patients, and additional studies are needed to determine if strict post-EVAR surveillance is necessary, and its effect on long-term clinical outcome.