Andrew W. Hoel

Under-representation of Women and Ethnic Minorities in Vascular Surgery Randomized Controlled Trials

OBJECTIVES Gender and ethnicity are factors affecting the incidence and severity of vascular disease as well as subsequent treatment outcomes. Although well studied in other fields, balanced enrollment of patients with relevant demographic characteristics in vascular surgery randomized controlled trials (RCTs) is not well known. This study describes the reporting of gender and ethnicity data in vascular surgery RCTs and analyzes whether these studies adequately represent our diverse patient population. METHODS We conducted a retrospective review of United States-based RCTs from 1983 through 2007 for three broadly defined vascular procedures: aortic aneurysm repair (AAR), carotid revascularization (CR), and lower extremity revascularization (LER). Included studies were examined for gender and ethnicity data, study parameters, funding source, and geographic region. The Nationwide Inpatient Sample (NIS) database was analyzed to obtain group-specific procedure frequency as an estimate of procedure frequency in the general population. RESULTS We reviewed 77 studies, and 52 met our inclusion criteria. Only 85% reported gender, and 21% reported ethnicity. Reporting of ethnicity was strongly associated with larger (>280 participants), multicenter, government-funded trials (P < .001 for all). Women are disproportionately under-represented in RCTs for all procedure categories (AAR, 9.0% vs 21.5%; CR, 30.0% vs 42.9%; LER, 22.4% vs 41.3%). Minorities are under-represented in AAR studies (6.0% vs 10.7%) and CR studies (6.9% vs 9.5%) but are over-represented in LER studies (26.0% vs 21.8%, P < .001 for all). CONCLUSIONS Minority ethnicity and female gender are under-reported and under-represented in vascular surgery RCTs, particularly in small, non-government-funded and single-center trials. The generalizability of some trial results may not be applicable to these populations. Greater effort to enroll a balanced study population in RCTs may yield more broadly applicable results.

Variation in smoking cessation after vascular operations

OBJECTIVE Smoking is the most important modifiable risk factor for patients with vascular disease. The purpose of this study was to examine smoking cessation rates after vascular procedures and delineate factors predictive of postoperative smoking cessation. METHODS The Vascular Study Group of New England registry was used to analyze smoking status preoperatively and at 1 year after carotid endarterectomy, carotid artery stenting, lower extremity bypass, and open and endovascular abdominal aortic aneurysm repair between 2003 and 2009. Of 10,734 surviving patients after one of these procedures, 1755 (16%) were lost to follow-up and 1172 (11%) lacked documentation of their smoking status at follow-up. The remaining 7807 patients (73%) were available for analysis. Patient factors independently associated with smoking cessation were determined using multivariate analysis. The relative contribution of patient and procedure factors including treatment center were measured by χ-pie analysis. Variation between treatment centers was further evaluated by calculating expected rates of cessation and by analysis of means. Vascular Study Group of New England surgeons were surveyed regarding their smoking cessation techniques (85% response rate). RESULTS At the time of their procedure, 2606 of 7807 patients (33%) were self-reported current smokers. Of these, 1177 (45%) quit within the first year of surgery, with significant variation by procedure type (open abdominal aortic aneurysm repair, 50%; endovascular repair, 49%; lower extremity bypass, 46%; carotid endarterectomy, 43%; carotid artery stenting, 27%). In addition to higher smoking cessation rates with more invasive procedures, age >70 years (odds ratio [OR], 1.90; 95% confidence interval [CI], 1.30-2.76; P < .001) and dialysis dependence (OR, 2.38; 95% CI, 1.04-5.43; P = .04) were independently associated with smoking cessation, whereas hypertension (OR, 1.23; 95% CI, 1.00-1.51; P = .051) demonstrated a trend toward significance. Treatment center was the greatest contributor to smoking cessation, and there was broad variation in smoking cessation rates, from 28% to 62%, between treatment centers. Cessation rates were higher than expected in three centers and significantly lower than expected in two centers. Among survey respondents, 78% offered pharmacologic therapy or referral to a smoking cessation specialist, or both. The smoking cessation rate for patients of these surgeons was 48% compared with 33% in those who did not offer medications or referral (P < .001). CONCLUSIONS Patients frequently quit smoking after vascular surgery, and multiple patient-related and procedure-related factors contribute to cessation. However, we note significant influence of treatment center on cessation as well as broad variation in cessation rates between treatment centers. This variation indicates an opportunity for vascular surgeons to impact smoking cessation at the time of surgery.

Participation in the Vascular Quality Initiative is associated with improved perioperative medication use, which is associated with longer patient survival

OBJECTIVE Medical management (MM) with antiplatelet (AP) and statin therapy is recommended for most patients undergoing vascular surgery and has been advocated by the Vascular Quality Initiative (VQI). We analyzed the effect of VQI participation on perioperative (preoperative and postoperative) MM use over time and the effect of discharge MM on patient survival. METHODS We studied VQI patients treated with MM preoperatively and at discharge from 2005 to 2014, including all elective carotid endarterectomy/carotid stenting (n = 28,092), suprainguinal/infrainguinal bypass (n = 11,362), peripheral vascular interventions (n = 24,476), open/endovascular abdominal aortic aneurysm repair (n = 13,503), and thoracic endovascular aneurysm repair (n = 702). We examined trends of MM use over time, as well as the effect of duration of VQI participation on MM use. Multivariable logistic regression analysis was performed to identify factors associated with MM use. In addition, the Cox proportional hazards model was used to identify factors associated with 5-year survival. RESULTS MM with AP and statin preoperatively and postoperatively across VQI centers improved from 55% in 2005 to 68% in 2009, with a subsequent overall decline to 62% by 2014, coincident with many new centers with lower MM rates joining VQI in 2010. Longer center participation in VQI was associated with improved perioperative MM overall. This was also noted across all procedure types, with MM increasing from 47% to 82% for aneurysm repairs and 69% to 83% for carotid procedures from 1 to 12 years of participation in VQI. After multivariable adjustment, centers in VQI ≥3 years were 30% more likely to have patients on MM (odds ratio, 1.3, 95% confidence interval [CI], 1.3-1.4). Importantly, discharge on AP and statin therapy was associated with improved 5-year survival, compared with discharge on neither medication (82% [95% CI, 81%-83%] vs 67% [95% CI, 62%-72%]), and an adjusted hazard ratio for death of 0.6 (95% CI, 0.5-0.7; P < .001). Discharge on a single medication was associated with intermediate survival at 5 years (AP only: 77% [95% CI, 75%-79%]; statin only: 73% [95% CI, 68%-77%]). CONCLUSIONS These data demonstrate that MM is associated with improved survival after a number of vascular procedures. Importantly, VQI participation improves the use of MM, demonstrating that involvement in an organized quality effort can affect patient outcomes.

Outcomes of Thoracic Endovascular Aortic Repair and Subclavian Revascularization Techniques

BACKGROUND Practice guidelines for management of the left subclavian artery (LSA) during thoracic endovascular aortic repair (TEVAR) are based on low-quality evidence, and there is limited literature that addresses optimal revascularization techniques. The purpose of this study was to compare outcomes of LSA coverage during TEVAR and revascularization techniques. STUDY DESIGN We performed a single-center retrospective cohort study from 2001 to 2013. Patients were categorized by LSA revascularization and by revascularization technique, carotid-subclavian bypass (CSB), or subclavian-carotid transposition (SCT). Thirty-day and mid-term stroke, spinal cord ischemia, vocal cord paralysis, upper extremity ischemia, primary patency of revascularization, and mortality were compared. RESULTS Eighty patients underwent TEVAR with LSA coverage, 25% (n = 20) were unrevascularized and the remaining patients underwent CSB (n = 22 [27.5%]) or SCT (n = 38 [47.5%]). Mean follow-up time was 24.9 months. Comparisons between unrevascularized and revascularized patients were significant for a higher rate of 30-day stroke (25% vs 2%; p = 0.003) and upper extremity ischemia (15% vs 0%; p = 0.014). However, there was no difference in 30-day or mid-term rates of spinal cord ischemia, vocal cord paralysis, or mortality. There were no statistically significant differences in 30-day or midterm outcomes for CSB vs SCT. Primary patency of revascularizations was 100%. Survival analysis comparing unrevascularized vs revascularized LSA was statistically significant for freedom from stroke and upper extremity ischemia (p = 0.02 and p = 0.003, respectively). After adjustment for advanced age, urgency, and coronary artery disease, LSA revascularization was associated with lower rates of perioperative adverse events (odds ratio = 0.23; p = 0.034). CONCLUSIONS During TEVAR, LSA coverage without revascularization is associated with an increased risk of stroke and upper extremity ischemia. When LSA coverage is required during TEVAR, CSB and SCT are equally acceptable options.

Results of transcaval embolization for sac expansion from type II endoleaks after endovascular aneurysm repair.

OBJECTIVE Management of type II endoleaks after endovascular aneurysm repair can be problematic. This study reports our experience with a relatively novel strategy to treat this complication, transcaval coil embolization (TCCE) of the aneurysm sac. METHODS We reviewed 29 consecutive patients undergoing TCCE from 2010 to 2013. Demographics, operative details, and outcomes were assessed. RESULTS Since 2006, 29 TCCEs have been performed at our institution in 26 patients for sac expansion from type II endoleaks. Patients were male (83%) and former or current smokers (88%), with an average age of 78 ± 7.1 years. TCCE was performed a mean of 4.2 ± 4 years after initial endovascular aneurysm repair. Endoleaks resulted in a mean sac growth of 1.2 ± 1 cm in diameter and 37% ± 32% by volume. Forty-six percent had prior procedures (5 translumbar, 3 transarterial, 3 transcaval, 1 aortic cuff, and 1 iliac limb extension). Two patients had no flow identified in the aneurysm sac after puncture was successful, and one was found to have a hygroma rather than arterial flow. An additional two patients had ultimate embolization from sac access between the endograft iliac limb and arterial wall after transcaval puncture failed, for a 90% procedural success (83% for transcaval technical success). Mean fluoroscopy time was 27 ± 13 minutes with 29 ± 21 mL of contrast material used and a median of 10 coils per case. Additional adjuncts included thrombin injection (17%), intravascular ultrasound (14%), sac pressure measurements (28%), and on-table integrated computed tomography (17%). Median length of stay was 1 day (range, 0-5 days). There were no procedural adverse events. Reintervention was required in five cases (three repeated TCCEs, two graft relinings). One-year freedom from reintervention was 95%. At a mean 16.5 months of follow-up, 70% experienced no further endoleak and had stable or decreasing sac diameters. There have been no ruptures during follow-up. CONCLUSIONS In this series, TCCE for treatment of aneurysm enlargement due to type II endoleaks was safe and relatively effective despite prior failed interventions in nearly half of the cases. TCCE is a useful alternative in cases in which the anatomy makes other approaches difficult or impossible.

A comparison of results with eversion versus conventional carotid endarterectomy from the Vascular Quality Initiative and the Mid-America Vascular Study Group.

OBJECTIVE Carotid endarterectomy (CEA) is usually performed with eversion (ECEA) or conventional (CCEA) technique. Previous studies report conflicting results with respect to outcomes for ECEA and CCEA. We compared patient characteristics and outcomes for ECEA and CCEA. METHODS Deidentified data for CEA patients were obtained from the Society for Vascular Surgery Vascular Quality Initiative (SVS VQI) database for years 2003 to 2013. Second (contralateral) CEA, reoperative CEA, CEA after previous carotid stenting, or CEA concurrent with cardiac surgery were excluded, leaving 2365 ECEA and 17,155 CCEA for comparison. Univariate analysis compared patients, procedures, and outcomes. Survival analysis was also performed for mortality. Multivariate analysis was used selectively to examine the possible independent predictive value of variables on outcomes. RESULTS Groups were similar with respect to sex, demographics, comorbidities, and preoperative neurologic symptoms, except that ECEA patients tended to be older (71.3 vs 69.8 years; P < .001). CCEA was more often performed with general anesthesia (92% vs 80%; P < .001) and with a shunt (59% vs 24%; P < .001). Immediate perioperative ipsilateral neurologic events (ECEA, 1.3% vs CCEA, 1.2%; P = .86) and any ipsilateral stroke (ECEA, 0.8% vs CCEA, 0.9%; P = .84) were uncommon in both groups. ECEA tended to take less time (median 99 vs 114 minutes; P < .001). However, ECEA more often required a return to the operating room for bleeding (1.4% vs 0.8%; P = .002), a difference that logistic regression analysis showed was only partly explained by differential use of protamine. Life-table estimated 1-year freedom from any cortical neurologic event was similar (96.7% vs 96.7%). Estimated survival was similar comparing ECEA with CCEA at 1 year (96.7% vs 95.9%); however, estimated survival tended to decline more rapidly in ECEA patients after ∼2 years. Cox proportional hazards modeling confirmed that independent predictors of mortality included age, coronary artery disease, chronic obstructive pulmonary disease, and smoking, but also demonstrated that CEA type was not an independent predictor of mortality. The 1-year freedom from recurrent stenosis >50% was lower for ECEA (88.8% vs 94.3%, P < .001). However, ECEA and CCEA both had a very high rate of freedom from reoperation at 1 year (99.5% vs 99.6%; P = .67). CONCLUSIONS ECEA and CCEA appear to provide similar freedom from neurologic morbidity, death, and reintervention. ECEA was associated with significantly shorter procedure times. Furthermore, ECEA obviates the expenses, including increased operative time, associated with use of a patch in CCEA, and a shunt, more often used in CCEA in this database. These potential benefits may be reduced by a slightly greater requirement for early return to the operating room for bleeding.

Preoperative antiplatelet and statin treatment was not associated with reduced myocardial infarction after high-risk vascular operations in the Vascular Quality Initiative

OBJECTIVE Medical management with antiplatelet (AP) and statin therapy is recommended for nearly all patients undergoing vascular surgery to reduce cardiovascular events. We assessed the association between preoperative use of AP and statin medications and postoperative in-hospital myocardial infarction (MI) in patients undergoing high-risk open surgery. METHODS We studied patients who underwent elective suprainguinal (n = 3039) and infrainguinal (n = 8323) bypass and open infrarenal abdominal aortic aneurysm repair (n = 3007) in the Vascular Quality Initiative (VQI, 2005-2014). We assessed the association between AP or statin use and in-hospital postoperative MI and MI/death. Multivariable logistic analyses were performed to identify the patient, procedure, and preoperative medication factors associated with postoperative MI and MI/death across procedures and patient cardiac risk strata. Secondary end points included bleeding, transfusion, and thrombotic complications. RESULTS Most patients were taking both AP and statin preoperatively (56% both agents vs 19% AP only, 13% statin only, and 12% neither agent). Use of both agents was more common for patients in the highest cardiac risk stratum (low, 54%; intermediate, 59%; high, 61%; P < .01). Increased cardiac risk was associated with higher MI rates (1.8% vs 3.8% vs 6.5% for low, intermediate, and high risk; P < .01). By univariate analysis, MI rate was paradoxically higher for patients taking both agents (3.7%, vs statin only 2.8%, AP only 2.6%, or neither AP nor statin 2.4%; P = .003). After multivariable adjustment, rates of MI in patients taking preoperative AP only (odds ratio [OR], 0.9; 95% confidence interval [CI], 0.7-1.2) and statin only (OR, 0.8; 95% CI, 0.6-1.2) were not different from those in patients taking either or neither medication (neither agent compared with taking both agents: OR, 1.0; 95% CI, 0.7-1.4; P > .05 for all). Similarly, rates of MI/death were not associated with medication status after multivariable adjustment. Estimated blood loss >1 liter (OR, 2.4; 95% CI, 1.6-3.7; P < .01) and transfusions of 1 or 2 units (OR, 2.5; 95% CI, 2.0-3.3; P < .01) and ≥3 units (OR, 4.0; 95% CI, 3.1-5.3; P < .01) were highly associated with MI, with similar findings related to composite MI/death in multivariable analysis. Rates of blood loss were slightly higher with AP use for all procedures; however, increased transfusions occurred only for infrainguinal bypass with AP use. Rates of reoperation for bleeding, graft thrombosis, or graft revision did not differ by preoperative AP use. CONCLUSIONS Preoperative AP and statin medications as used in VQI were not associated with the rate of in-hospital MI/death after major open vascular operations. Rather, predicted cardiac risk and operative blood loss were significantly associated with in-hospital MI or MI/death. AP and statin medications appear to be more useful in reducing late mortality than early postoperative MI/death in VQI. However, they were not harmful, so their long-term benefit argues for continued use.

National variation in preoperative imaging, carotid duplex ultrasound criteria, and threshold for surgery for asymptomatic carotid artery stenosis

OBJECTIVE Carotid endarterectomy (CEA) for asymptomatic carotid artery stenosis is among the most common procedures performed in the United States. However, consensus is lacking regarding optimal preoperative imaging, carotid duplex ultrasound criteria, and ultimately, the threshold for surgery. We sought to characterize national variation in preoperative imaging, carotid duplex ultrasound criteria, and threshold for surgery for asymptomatic CEA. METHODS The Society for Vascular Surgery Vascular Quality Initiative (VQI) database was used to identify all CEA procedures performed for asymptomatic carotid artery stenosis between 2003 and 2014. VQI currently captures 100% of CEA procedures performed at >300 centers by >2000 physicians nationwide. Three analyses were performed to quantify the variation in (1) preoperative imaging, (2) carotid duplex ultrasound criteria, and (3) threshold for surgery. RESULTS Of 35,695 CEA procedures in 33,488 patients, the study cohort was limited to 19,610 CEA procedures (55%) performed for asymptomatic disease. The preoperative imaging modality used before CEA varied widely, with 57% of patients receiving a single preoperative imaging study (duplex ultrasound imaging, 46%; computed tomography angiography, 7.5%; magnetic resonance angiography, 2.0%; cerebral angiography, 1.3%) and 43% of patients receiving multiple preoperative imaging studies. Of the 16,452 asymptomatic patients (89%) who underwent preoperative duplex ultrasound imaging, there was significant variability between centers in the degree of stenosis (50%-69%, 70%-79%, 80%-99%) designated for a given peak systolic velocity, end diastolic velocity, and internal carotid artery-to-common carotid artery ratio. Although 68% of CEA procedures in asymptomatic patients were performed for an 80% to 99% stenosis, 26% were performed for a 70% to 79% stenosis, and 4.1% were performed for a 50% to 69% stenosis. At the surgeon level, the range in the percentage of CEA procedures performed for a <80% asymptomatic carotid artery stenosis is from 0% to 100%. Similarly, at the center level, institutions range in the percentage of CEA procedures performed for a <80% asymptomatic carotid artery stenosis from 0% to 100%. CONCLUSIONS Despite CEA being an extremely common procedure, there is widespread variation in the three primary determinants-preoperative imaging, carotid duplex ultrasound criteria, and threshold for surgery-of whether CEA is performed for asymptomatic carotid stenosis. Standardizing the approach to care for asymptomatic carotid artery stenosis will mitigate the significant downstream effects of this variation on health care costs.

Aneurysmal Disease: Thoracic Aorta

Thoracic aortic aneurysms are clinically significant for their high mortality risk in the face of rupture. This article reviews the natural history and pathophysiology of thoracic and thoracoabdominal aortic aneurysms, discusses the evaluation of these patients, and details the treatment options. Specifically discussed are treatment advances arising from the development of endovascular technology.

Restenosis after carotid endarterectomy performed with routine intraoperative duplex ultrasonography and arterial patch closure: a contemporary series

The restenosis rates of 5% to 15% have been reported after carotid endarterectomy (CEA). We undertook this investigation to determine whether the routine practice of carotid artery patch closure and intraoperative completion duplex ultrasonography would result in lower rates of carotid restenosis after CEA. All consecutive carotid endarterectomies performed between 2000 and 2004 at a single institution were reviewed retrospectively. Patients underwent CEA using a longitudinal arteriotomy, followed by routine patching and intraoperative completion duplex ultrasonography. Only patients with at least one postoperative duplex scan performed at a minimum of 180 days after CEA were included. During the 5-year study period, 407 consecutive carotid endarterectomies were performed, with a combined 30-day stroke and mortality rate of 2.5%; 217 patients (53%) had one or more duplex ultrasound examinations performed at least 180 days after CEA. The mean follow-up duration was 692 days. Of the patients who underwent intraoperative intervention based on the results of the completion duplex study, none experienced restenosis, stroke, or death. CEA that is performed with routine patching and intraoperative duplex completion ultrasonography is a safe, durable operation with restenosis rates below those commonly reported.