Use of Protamine for Anticoagulation During Carotid Endarterectomy: A Meta-analysis

IMPORTANCE

Protamine sulfate can be administered at the conclusion of carotid endarterectomy (CEA) to reverse the anticoagulant effects of heparin and to limit the risk for postoperative bleeding. Protamine use remains controversial owing to concern for increased thrombotic complications with its use.

OBJECTIVE

To review the evidence for and against protamine use, both in its association with increased thrombotic complications and with decreased bleeding.

DATA SOURCES

We searched Medline (1946-2014), EMBASE (1966-2014), Cochrane Library (1972-2014), clinical trial registries (World Health Organization International Clinical Trials Registry and clinicaltrials.gov), and abstracts from conferences of the Society of Vascular Surgery (2002-2014) and American Heart Association Scientific Sessions (1980-2014) in November 2014. No language restrictions were applied.

STUDY SELECTION

We included clinical trials and observational studies comparing reversal of heparin with protamine sulfate vs no reversal in patients undergoing carotid revascularization and reporting stroke during hospitalization. Of 360 records screened, 12 studies (3%) of CEA were eligible for data pooling.

DATA EXTRACTION AND SYNTHESIS

Two reviewers extracted data and assessed quality. Random-effects models were used to summarize relative risks (RRs).

MAIN OUTCOME AND MEASURE

Stroke after CEA.

RESULTS

We included 12 observational studies involving 10,621 patients in the meta-analysis. Event rates did not differ significantly between patients who received protamine vs those who did not for the following outcomes: stroke (RR, 0.84; 95% CI, 0.55-1.29; I(2) = 15%; 9 studies), myocardial infarction (RR, 0.89; 95% CI, 0.53-1.51; I(2) = 0%; 3 studies), or mortality (RR, 0.9, 95% CI, 0.62-1.29; I(2) = 0%; 7 studies). The use of protamine was associated with a significant decrease in major bleeding complications requiring reoperation (RR, 0.57; 95% CI, 0.39-0.84; I(2) = 32%; 10 studies).

CONCLUSIONS AND RELEVANCE

Based on available evidence, the use of protamine following CEA is associated with a reduction in bleeding complications, without increasing major thrombotic outcomes, including stroke, myocardial infarction, or death.

Comparing Long-term Mortality After Carotid Endarterectomy vs Carotid Stenting Using a Novel Instrumental Variable Method for Risk Adjustment in Observational Time-to-Event Data

IMPORTANCE

Choosing between competing treatment options is difficult for patients and clinicians when results from randomized and observational studies are discordant. Observational real-world studies yield more generalizable evidence for decision making than randomized clinical trials, but unmeasured confounding, especially in time-to-event analyses, can limit validity.

OBJECTIVES

To compare long-term survival after carotid endarterectomy (CEA) and carotid artery stenting (CAS) in real-world practice using a novel instrumental variable method designed for time-to-event outcomes, and to compare the results with traditional risk-adjustment models used in observational research for survival analyses.

DESIGN, SETTING, AND PARTICIPANTS

A multicenter cohort study was performed. The Vascular Quality Initiative, an observational quality improvement registry, was used to compare long-term mortality after CEA vs CAS. The study included 86 017 patients who underwent CEA (n = 73 312) or CAS (n = 12 705) between January 1, 2003, and December 31, 2016. Patients were followed up for long-term mortality assessment by linking the registry data to Medicare claims. Medicare claims data were available through September 31, 2015.

EXPOSURE

Procedure type (CEA vs CAS).

MAIN OUTCOMES AND MEASURES

The hazard ratios (HRs) of all-cause mortality using unadjusted, adjusted, propensity-matched, and instrumental variable methods were examined. The instrumental variable was the proportion of CEA among the total carotid procedures (endarterectomy and stenting) performed at each hospital in the 12 months before each patient's index operation and therefore varies over the study period.

RESULTS

Participants who underwent CEA had a mean (SD) age of 70.3 (9.4) years compared with 69.1 (10.4) years for CAS, and most were men (44 191 [60.4%] for CEA and 8117 [63.9%] for CAS). The observed 5-year mortality was 12.8% (95% CI, 12.5%-13.2%) for CEA and 17.0% (95% CI, 16.0%-18.1%) for CAS. The unadjusted HR of mortality for CEA vs CAS was 0.67 (95% CI, 0.64-0.71), and Cox-adjusted and propensity-matched HRs were similar (0.69; 95% CI, 0.65-0.74 and 0.71; 95% CI, 0.65-0.77, respectively). These findings are comparable with published observational studies of CEA vs CAS. However, the association between CEA and mortality was more modest when estimated by instrumental variable analysis (HR, 0.83; 95% CI, 0.70-0.98), a finding similar to data reported in randomized clinical trials.

CONCLUSIONS AND RELEVANCE

The study found a survival advantage associated with CEA over CAS in unadjusted and Cox-adjusted analyses. However, this finding was more modest when using an instrumental variable method designed for time-to-event outcomes for risk adjustment. The instrumental variable-based results were more similar to findings from randomized clinical trials, suggesting this method may provide less biased estimates of time-dependent outcomes in observational analyses.

Association of Adoption of Transcarotid Artery Revascularization With Center-Level Perioperative Outcomes

IMPORTANCE

Transcarotid artery revascularization (TCAR) may serve as a safer alternative to carotid endarterectomy (CEA) for certain patients with carotid artery stenosis.

OBJECTIVE

To determine the center-level association of TCAR adoption with overall perioperative outcomes for TCAR and CEA combined at centers performing both procedures.

DESIGN, SETTING, AND PARTICIPANTS

This comparative-effectiveness research was conducted with a difference-in-difference analysis using retrospective data from 2015 to 2019 from the Vascular Quality Initiative registry, a consortium of more than 400 centers in North America. Included patients underwent TCAR or CEA for carotid artery stenosis. Patients who underwent transfemoral carotid stenting were excluded. Data were analyzed from December 2019 through August 2020.

EXPOSURES

Center-level adoption of TCAR vs not.

MAIN OUTCOMES AND MEASURES

The rate of major adverse cardiovascular events (MACE), a composite of in-hospital stroke, myocardial infarction, or death at 30 days, was measured.

RESULTS

Among 86 027 patients who underwent revascularization for carotid artery stenosis, 7664 patients (8.9%) underwent TCAR (mean [SD] age, 73.1 [9.6] years; 2788 [36.4%] women; 6938 White patients [90.6%]; and 3741 patients with symptoms [48.8%]) and 78 363 patients (91.1%) underwent CEA (mean [SD] age, 70.6 [9.2] years; 30 928 [39.5%] women; 70 663 White patients [90.2%]; and 37 883 patients with symptoms [48.3%]). The number of centers performing both TCAR and CEA increased from 15 centers in 2015 to 247 centers in 2019, a more than 16-fold increase. The proportion of all carotid procedures that were TCARs increased from 90 of 12 276 (0.7%) in 2015 to 2718 of 15 956 (17.0%) in 2019, a 24-fold increase. Overall, the crude rate of MACE was similar for TCAR and CEA (178 patients [2.3%] after TCAR vs 1842 patients [2.4%] after CEA; P = .91). However, the rate of MACE over time decreased for CEA (406 of 16 404 patients [2.5%] in 2015 vs 189 of 10 097 patients [1.9%] in 2019; P for trend < .001). The rate of MACE over time decreased for TCAR as well, but the change was not statistically significant (4 of 128 patients [3.1%] in 2016 vs 59 of 2718 patients [2.2%] in 2019; P for trend = .07). Difference-in-difference analysis demonstrated that centers that adopted TCAR had a 10% decrease in the likelihood of MACE at 12 months after TCAR adoption vs if those centers had continued to perform CEA alone (odds ratio, 0.90; 95% CI, 0.81-0.99; P = .04).

CONCLUSIONS AND RELEVANCE

This comparative-effectiveness study of a cohort of patients who underwent TCAR or CEA found that availability of TCAR at a hospital was associated with a decrease in the likelihood of perioperative MACE after carotid revascularization.

A regional quality improvement effort to increase beta blocker administration before vascular surgery

OBJECTIVE

To determine if a regional quality improvement effort can increase beta-blocker utilization prior to vascular surgery and decrease the incidence of postoperative myocardial infarction (POMI).

METHODS

A quality improvement effort to increase perioperative beta blocker utilization was implemented in 2003 at centers participating in the Vascular Study Group of New England (VSGNE). A 90% target was set and feedback given at biannual meetings. Beta blocker utilization (<1 month preoperative versus chronic) and POMI rates were prospectively collected for patients undergoing open abdominal aortic aneurysm (AAA) repair (n = 926) and lower extremity bypass (LEB; n = 2,123) from 2003 through 2008. Predictors of POMI were determined using multivariate logistic regression. Rates of beta blocker administration and POMI were analyzed over time, and across strata of patient risk based on a multivariate model.

RESULTS

Perioperative beta blocker treatment increased from 68% of patients in the first 3 months of 2005 to 88% by the last 3 months of 2008 (P < .001). In 2003, 44% of patients not on chronic beta blockers were treated with preoperative beta blockers; by 2008, 78% of patients not on chronic beta blockers were started perioperatively on these medications (P < .001). Beta blocker utilization increased across all centers and surgeons participating during the study period, and increased in patients of low, medium, and high cardiac risk. However, the rate of POMI did not change over time (5.2% in 2003, 5.5% in 2008; P = .876), although a trend towards lower POMI rate was seen in patients on preoperative beta blockers (4.4% in 2003-2005, 2.6% in 2006-2008; P = .43). In multivariable modeling we found that age >70 (odds ratio [OR], 2.1), positive stress test (OR, 2.2), congestive heart failure (CHF; OR, 1.7), chronic beta blocker administration (OR, 1.7), resting heart rate <70 (OR, 1.8), and diabetes (OR, 1.6) were associated with POMI. Resting heart rate was similar for patients on chronic (67), preoperative (70), and no beta blockers (70; P = .521).

CONCLUSIONS

Our regional quality improvement effort successfully increased perioperative beta blocker utilization. However, this was not associated with reduced rates of POMI or resting heart rate. While this demonstrates the effectiveness of regional quality improvement efforts in changing practice patterns, further work is necessary to more precisely identify those patients who will benefit from beta blockade at the time of vascular surgery.

Completion imaging after carotid endarterectomy in the Vascular Study Group of New England

OBJECTIVES

We studied surgeons' practice patterns in the use of completion imaging (duplex or arteriography), and their association with 30-day stroke/death and 1-year restenosis after carotid endarterectomy (CEA).

METHODS

Using a retrospective analysis of 6115 CEAs, we categorized surgeons based on use of completion imaging as rarely (<5% of CEAs), selective (5% to 90%), or routine (≥90%). Crude and risk-adjusted 30-day stroke/death and 1-year restenosis rates were examined across surgeon practice patterns. Finally, we audited 90 operative reports of patients who underwent re-exploration and characterized findings and interventions. We analyzed the effect of re-exploration on outcomes.

RESULTS

Practice patterns in completion imaging varied: 51% of surgeons performed completion imaging rarely, 22% selectively, and 27% routinely. Crude 30-day stroke/death rates were highest among surgeons who routinely used completion imaging (rarely: 1.7%; selectively: 1.2%, routinely: 2.4%; P = .05). However, after adjusting for patient characteristics predictive of stroke/death, the effect of surgeon practice pattern was not statistically significant (odds ratio [OR] for routine-use surgeons, 1.42; 95% CI, 0.93-2.17; P = .10; selective-use surgeons, 0.75; 95% CI, 0.40-1.41; P = .366). Stenosis >70% at 1 year showed a trend toward lowest rates for surgeons who performed completion imaging (rarely: 2.8%, selectively: 1.1%, and routinely: 1.1%; P = .09). This effect became statistically significant for selective-use surgeons after adjustment (hazard risk [HR] for selective-use surgeons, 0.52; 95% CI, 0.29-0.92; P = .02). Overall, 178 patients (2.9%) underwent operative re-exploration. Routine-use surgeons were most likely to perform re-exploration (7.6% routine, 0.8% selective, 0.9% rare; P < .001). An audit of 90 re-explored patients demonstrated technical problems, the most common being flap, debris, and plaque. Rates of stroke/death were higher among patients who underwent re-exploration (3.9% vs 1.7%; P = .03); however, this affect was attenuated after adjustment (OR, 2.1; 95% CI, 0.9-5.0; P = .08).

CONCLUSIONS

The use of completion imaging during CEA varies widely across our region. There is little evidence that surgeons who use completion imaging have lower rates of 30-day stroke/death, although selective use of completion imaging is associated with a small but a significant reduction in stenosis 1 year after surgery. We also demonstrate an association between re-exploration and higher risk of 30-day stroke/death, although this effect was attenuated after adjustment for patient-level predictors of stroke/death. Future work is needed to direct the selective use of completion imaging to prevent stroke, rather than cause unnecessary re-exploration.

Preoperative symptom type influences the 30-day perioperative outcomes of carotid endarterectomy and carotid stenting in the Society for Vascular Surgery Vascular Registry

OBJECTIVE

The objective of this study was to determine the effect of presenting symptom types on 30-day periprocedural outcomes of carotid endarterectomy (CEA) and carotid artery stenting (CAS) in contemporary vascular practice.

METHODS

Retrospective review was undertaken of the Society for Vascular Surgery Vascular Registry database subjects who underwent CEA or CAS from 2004 to 2011. Patients were grouped by discrete 12-month preprocedural ipsilateral symptom type: stroke, transient ischemic attack (TIA), transient monocular blindness (TMB), or asymptomatic (ASX). Risk-adjusted odds ratios (ORs) were used to compare the likelihood of the 30-day outcomes of death, stroke, and myocardial infarction (MI) and the composite outcomes of death + stroke and death + stroke + MI.

RESULTS

Symptom type significantly influences risk-adjusted 30-day outcomes for carotid intervention. Presentation with stroke predicted the poorest outcomes (death + stroke + MI composite: OR, 1.3; 95% confidence interval [CI], 0.83-2.03 vs TIA; OR, 2.56; 95% CI, 1.18-5.57 vs TMB; OR, 2.12; 95% CI, 1.46-3.08 vs ASX), followed by TIA (death + stroke + MI composite: OR, 1.97; 95% CI, 0.91-4.25 vs TMB; OR, 1.63; 95% CI, 1.14-2.33 vs ASX). For both CAS and CEA patients, presentation with stroke or TIA predicted a higher risk of periprocedural stroke than in ASX patients. Presentation with stroke predicted higher 30-day risk of death with CAS but not with CEA. MI rates were not affected by presenting symptom type. The 30-day outcomes for the TMB and ASX patient groups were equivalent in both treatment arms.

CONCLUSIONS

Presenting symptom type significantly affects the 30-day outcomes of both CAS and CEA in contemporary vascular surgical practice. Presentation with stroke and TIA predicts higher rates of periprocedural complications, whereas TMB presentation predicts a periprocedural risk profile similar to that of ASX disease.

Effectiveness of Blood Lipid Management in Patients With Peripheral Artery Disease

BACKGROUND

Low-density lipoprotein cholesterol (LDL-C) is associated with heightened risk of major adverse cardiovascular events (MACE) and major adverse limb events (MALE) in peripheral artery disease (PAD). Lipid-lowering therapies (LLT) that reduce LDL-C decrease this risk.

OBJECTIVES

The authors examined LLT use and actual achieved LDL-C in PAD.

METHODS

PAD patients in MarketScan from 2014 to 2018 were identified. Outcomes included LLT use, defined as high-intensity (HI) (high-intensity statin, statin plus ezetimibe, or PCSK9 inhibitor), low-intensity (any other lipid regimen), or no therapy, and follow-up LDL-C. Factors associated with LDL-C <70 mg/dl were identified with multivariable logistic regression.

RESULTS

Among 250,103 PAD patients, 20.5% and 39.5% were treated at baseline with HI and low-intensity LLT, respectively; 40.0% were on no LLT. Over a 15-month median follow-up period, HI LLT use increased by 1.5%. Among 18,747 patients with LDL-C data, at baseline, 25.1% were on HI LLT, median LDL-C was 91 mg/dl, and 24.5% had LDL-C <70 mg/dl. Within the HI LLT subgroup, median LDL-C was 81 mg/dl, and 64% had LDL-C ≥70 mg/dl. At follow-up, HI LLT use increased by 3.7%, median LDL-C decreased by 4.0 mg/dl, and an additional 4.1% of patients had LDL-C <70 mg/dl. HI LLT use was greater after follow-up MACE (55.0%) or MALE (41.0%) versus no ischemic event (26.1%). After MACE or MALE, LDL-C was <70 mg/dl in 41.5% and 36.1% of patients, respectively, versus 27.1% in those without an event. Factors associated with follow-up LDL-C <70 mg/dl included smoking, hypertension, diabetes, prior lower extremity revascularization, and prior myocardial infarction but not prior acute or critical limb ischemia.

CONCLUSIONS

In PAD, LLT use is suboptimal, LDL-C remains elevated, and LLT intensity is a poor surrogate for achieved LDL-C. Less aggressive lipid management was observed in PAD versus cardiovascular disease, highlighting missed opportunities for implementation of proven therapies in PAD.

Late outcomes after endovascular and open repair of large abdominal aortic aneurysms

OBJECTIVE

The risk of aortic abdominal aneurysm (AAA) rupture increases with an increasing aneurysm diameter. However, the effect of the AAA diameter on late outcomes after aneurysm repair is unclear. Therefore, we assessed the association of a large AAA diameter with late outcomes for patients undergoing open and endovascular AAA repair.

METHODS

We identified all patients who had undergone elective open or endovascular infrarenal aneurysm repair from 2003 to 2016 in the Vascular Quality Initiative linked to Medicare claims for long-term outcomes. A large AAA diameter was defined as a diameter >65 mm. We assessed the 5-year reintervention, rupture, mortality, and follow-up rates. We constructed propensity scores and used inverse probability-weighted Kaplan-Meier estimations and Cox proportional hazard models to identify independent associations between large AAA repair and our outcomes.

RESULTS

Of the 21,119 aneurysm repairs identified, 15.2% were for large AAAs. Of the 21,119 repairs, 19,017 were endovascular and 2102 were open. The large AAA cohort was less likely to have undergone endovascular aneurysm repair (EVAR; 84.9% vs 91%; P < .001), more likely to be older (median age, 76 vs 75 years; P < .001), and were less likely to be women (16.2% vs 21.7%; P < .001). After EVAR, patients with large AAAs had had lower adjusted 5-year freedom from reintervention (73.9% vs 84.6%; P < .001), freedom from rupture (88.5% vs 93.6%; P < .001), survival (58.0% vs 66.4%; P < .001), and freedom from loss to follow-up (77.7% vs 83.3%; P < .001) compared with patients with smaller AAAs. However, after open repair, the adjusted 5-year freedom from reintervention (95.8% vs 93.3%; P = .11), freedom from rupture (97.4% vs 97.8%; P = .32), survival (70.4% vs 74.0%; P = .13), and loss to follow-up (60.5% vs 62.8%; P = .86) were similar to the results for patients with smaller AAAs. For patients with large AAAs, the adjusted 5-year survival was lower after EVAR than that after open repair (55.3% vs 63.7%) but not after smaller AAA repair (67.3% vs 70.6%).

CONCLUSION

The 5-year adjusted reintervention, ruptures, mortality, and loss to follow-up rates for patients who had undergone large AAA EVAR were higher than those for patients who had undergone small AAA EVAR and large AAA open repair. Therefore, for patients with large AAAs who are medically fit, open repair should be strongly considered. Furthermore, these findings highlight the necessity for rigorous long-term follow-up after EVAR.

Carotid endarterectomy in asymptomatic patients with limited life expectancy

BACKGROUND AND PURPOSE

Data from randomized trials assert that asymptomatic patients undergoing carotid endarterectomy (CEA) must live 3 to 5 years to realize the benefit of surgery. We examined how commonly CEA is performed among asymptomatic patients with limited life expectancy.

METHODS

Within the American College of Surgeons National Quality Improvement Project we identified 8 conditions associated with limited life expectancy based on survival estimates using external sources. We then compared rates of 30-day stroke, death, and myocardial infarction after CEA between asymptomatic patients with and without life-limiting conditions.

RESULTS

Of 12,631 CEAs performed in asymptomatic patients, 2525 (20.0%) were in patients with life-limiting conditions or diagnoses. The most common conditions were severe chronic obstructive pulmonary disease and American Society of Anesthesiologists Class IV designation. Patients with life-limiting conditions had significantly higher rates of perioperative complications, including stroke (1.8% versus 0.9%, P<0.001), death (1.4% versus 0.3%, P<0.001), and stroke/death (2.9% versus 1.1%, P<0.001). Even after adjustment for other comorbidities, patients with life-limiting conditions were nearly 3 times more likely to experience perioperative stroke or death than those without these conditions (OR, 2.8; 95% CI, 2.1-3.8; P<0.001).

CONCLUSION

CEA is performed commonly in asymptomatic patients with life-limiting conditions. Given the high rates of postoperative stroke/death in these patients as well as their limited life expectancy, the net benefit of CEA in this population remains uncertain. Health policy research examining the role of CEA in asymptomatic patients with life-limiting conditions is necessary and may serve as a potential source for significant healthcare savings in the future.

Patient Experience of Recovery After Major Leg Amputation for Arterial Disease

Objectives:

To date, studies of vascular amputees primarily examine quantitative outcomes following limb loss. Less is known about the patient’s perspective after major lower limb amputation. Here, we define and describe the postamputation recovery period.

Methods:

Qualitative study using purposive, maximum variation sampling on the variables of amputation level and times since surgery. We first conducted structured interviews with 20 participants (median age: 65 years, range: 45-88 years; 85% male; below knee amputation n = 14; above knee amputation n = 6; median time from amputation to interview = 16 months, range: 4-51 months). Findings were validated via a focus group with 5 amputees. Data were coded, analyzed, and interpreted by 2 reviewers.

Results:

All participants expressed the desire to have an active role in the decision to undergo amputation, even while acknowledging that limb salvage options were exhausted. Following amputation, participants described a 6-month recovery period when they learned to modify daily activities to accommodate their new functional and psychological needs. Participants defined recovery as when they had regained functional independence, which was described as a level of mobility that allowed them to perform daily activities with minimal assistance. Concerns that participants felt were poorly addressed included uncontrolled pain, feeling unprepared to live with an amputation, and questions about prosthetics. Two of the 5 focus group participants stated a preference for amputation earlier in the treatment course.

Conclusions:

Postamputation recovery has an early (up to 6 months) and late phase (after 6 months) and concludes when amputees regain what they perceive as independence. Patients desire to participate in amputation decision-making; in this study, some would have preferred amputation earlier in their clinical course. Attention to the domains that impact quality of life, and fostering a shared decision-making process, are opportunities to enhance postamputation recovery.

Association of Sex With Repair Type and Long-term Mortality in Adults With Abdominal Aortic Aneurysm

IMPORTANCE

Sex-based differences exist in the prevalence and clinical presentation of abdominal aortic aneurysm (AAA). However, it is unclear if sex is associated with AAA repair type and long-term mortality.

OBJECTIVE

To investigate whether a sex-related difference exists in mortality risk after AAA repair owing to differences in repair type.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study uses data from the Vascular Quality Initiative, a national clinical registry, and Medicare claims to investigate endovascular and surgical repair procedures performed between January 1, 2003, and September 30, 2015, in patients aged 65 years or older with AAA. The data were analyzed from October 1, 2018, to November 19, 2019.

EXPOSURE

Sex of the patient.

MAIN OUTCOMES AND MEASURES

Endovascular (EVR) or open surgical AAA repair type and subsequent long-term, all-cause mortality.

RESULTS

In this cohort study of 16 386 patients, 12 757 (77.9%) were men and 3629 (22.1%) were women. Women were more likely than men to be older (mean [SD] age, 77 [6.5] years vs 75 [6.6] years; P < .001), active smokers (33% vs 28%; P < .001), and to have smaller aneurysms (mean [SD] diameter, 57 [11.7] mm vs 59 [17.7] mm; P < .001). Surgical AAA repair was performed in 27% (983 of 3629) of women compared with 18% (2328 of 12 757) of men (P < .001). After inverse probability weighting for risk adjustment, women were more likely to receive open surgical repair than EVR repair (risk ratio, 1.65; 95% CI, 1.51-1.80). The 10-year unadjusted survival rate after EVR repair was 14% lower in women than in men (23% vs 37%; log-rank P < .001), but the rates were comparable after open surgical repair (36% in men vs 32% in women; log-rank P = .22). Risk-adjusted analysis showed that women were associated with higher mortality rates after EVR repair (hazard ratio, 1.13; 95% CI, 1.03-1.24), whereas both men and women had a similar risk of death after open surgical repair (hazard ratio, 0.94; 95% CI, 0.84-1.06). After further stratification by symptom severity, higher risk of mortality among women was limited to elective EVR and open surgical repair for ruptured AAA.

CONCLUSIONS AND RELEVANCE

In this study, women were 65% more likely than men to undergo open surgical repair. After EVR repair, women were 13% more likely to die than men, although no sex-based difference in mortality was found after open surgical repair. The differential treatment benefit of EVR repair in women is concerning given the shift toward an EVR-first approach to AAA repair.

Development of a Natural Language Processing Engine to Generate Bladder Cancer Pathology Data for Health Services Research

OBJECTIVE

To take the first step toward assembling population-based cohorts of patients with bladder cancer with longitudinal pathology data, we developed and validated a natural language processing (NLP) engine that abstracts pathology data from full-text pathology reports.

METHODS

Using 600 bladder pathology reports randomly selected from the Department of Veterans Affairs, we developed and validated an NLP engine to abstract data on histology, invasion (presence vs absence and depth), grade, the presence of muscularis propria, and the presence of carcinoma in situ. Our gold standard was based on an independent review of reports by 2 urologists, followed by adjudication. We assessed the NLP performance by calculating the accuracy, the positive predictive value, and the sensitivity. We subsequently applied the NLP engine to pathology reports from 10,725 patients with bladder cancer.

RESULTS

When comparing the NLP output to the gold standard, NLP achieved the highest accuracy (0.98) for the presence vs the absence of carcinoma in situ. Accuracy for histology, invasion (presence vs absence), grade, and the presence of muscularis propria ranged from 0.83 to 0.96. The most challenging variable was depth of invasion (accuracy 0.68), with an acceptable positive predictive value for lamina propria (0.82) and for muscularis propria (0.87) invasion. The validated engine was capable of abstracting pathologic characteristics for 99% of the patients with bladder cancer.

CONCLUSION

NLP had high accuracy for 5 of 6 variables and abstracted data for the vast majority of the patients. This now allows for the assembly of population-based cohorts with longitudinal pathology data.

Association of Smoking With Postprocedural Complications Following Open and Endovascular Interventions for Intermittent Claudication

Importance

Smoking is a key modifiable risk factor in the development and progression of peripheral artery disease, which often manifests as intermittent claudication (IC). Smoking cessation is a first-line therapy for IC, yet a minority of patients quit smoking prior to elective revascularization.

Objective

To assess if preprocedural smoking is associated with an increased risk of early postprocedural complications following elective open and endovascular revascularization.

Design, Setting, and Participants

This retrospective cohort study used nearest-neighbor (1:1) propensity score matching of 2011 to 2019 data from the Veterans Affairs Surgical Quality Improvement Program, including all cases with a primary diagnosis of IC and excluding emergent cases, primary procedures that were not lower extremity revascularization, and patients with chronic limb-threatening ischemia within 30 days of the intervention. All data were abstracted June 18, 2020, and analyzed from July 26, 2020, to June 30, 2021.

Exposures

Preprocedural cigarette smoking.

Main Outcomes and Measures

Any and organ system-specific (ie, wound, respiratory, thrombosis, kidney, cardiac, sepsis, and neurological) 30-day complications and mortality, overall and in prespecified subgroups.

Results

Of 14 350 included cases of revascularization, 14 090 patients (98.2%) were male, and the mean (SD) age was 65.7 (7.0) years. A total of 7820 patients (54.5%) were smoking within the preprocedural year. There were a total of 4417 endovascular revascularizations (30.8%), 4319 hybrid revascularizations (30.1%), and 5614 open revascularizations (39.1%). A total of 1594 patients (11.1%) had complications, and 57 (0.4%) died. Among 7710 propensity score-matched cases (including 3855 smokers and 3855 nonsmokers), 484 smokers (12.6%) and 34 nonsmokers (8.9%) experienced complications, an absolute risk difference (ARD) of 3.68% (95% CI, 2.31-5.06; P < .001). Compared with nonsmokers, any complication was higher for smokers following endovascular revascularization (26 [4.3%] vs 52 [2.1%]; ARD, 2.19%; 95% CI, 0.77-3.60; P = .003), hybrid revascularization (204 [17.3%] vs 163 [14.1%]; ARD, 3.18%; 95% CI, 0.23-6.13; P = .04), and open revascularization (228 [15.4%] vs 153 [10.3%]; ARD, 5.18%; 95% CI, 2.78-7.58; P < .001). Compared with nonsmokers, respiratory complications were higher for smokers following endovascular revascularization (20 [1.7%] vs 6 [0.5%]; ARD, 1.17%; 95% CI, 0.35-2.00; P = .009), hybrid revascularization (33 [2.8%] vs 10 [0.9%]; ARD, 1.93%; 95% CI, 0.85-3.02; P = .001), and open revascularization (32 [2.2%] vs 19 [1.3%]; ARD, 0.89%; 95% CI, 0-1.80; P = .06). Wound complications and graft failure were higher for smokers compared with nonsmokers following open interventions (wound complications: 146 [9.9%] vs 87 [5.8%]; ARD, 4.05%; 95% CI, 2.12-5.99; P < .001; graft failure: 33 [2.2%] vs 11 [0.7%]; ARD, 1.50%; 95% CI, 0.63-2.37; P = .001). In a sensitivity analysis, compared with active smokers (n = 5173; smoking within 2 weeks before the procedure), the risk of any complication was decreased by 65% for never smokers (n = 1197; adjusted odds ratio, 0.45; 95% CI, 0.34-0.59) and 29% for former smokers (n = 4755; cessation more than 1 year before the procedure; adjusted odds ratio, 0.71; 95% CI, 0.61-0.83; P = .001 for interaction).

Conclusions and Relevance

In this cohort study, more than half of patients with IC were smoking prior to elective revascularization, and complication risks were higher across all modalities of revascularization. These findings stress the importance of smoking cessation to optimize revascularization outcomes.

Outcomes of infrainguinal bypass determined by age in the Vascular Study Group of New England

BACKGROUND

Many believe extremes of age correlate with poorer outcomes in treatment for lower extremity peripheral arterial disease (PAD). We hypothesized that the youngest patients would have significantly poorer outcomes compared with older cohorts due to the precocious nature of their PAD.

METHODS

We studied all patients in the Vascular Study Group of New England database undergoing infrainguinal bypass for PAD between 2003 and 2013. Age was grouped by <50 years, 50 to 79 years, and ≥80 years. Our primary outcomes were 1-year freedom from a major adverse limb event (MALE), defined as ipsilateral amputation or need for secondary intervention, and amputation-free survival. A second analysis was performed to analyze the subgroup of patients aged <50 years with critical limb ischemia (CLI), which included a Cox regression model to determine risk factors for MALE or death at 1 year.

RESULTS

Of 5265 patients who were treated with infrainguinal bypass for PAD, 324 (6.2%) were aged <50 years. The mean age was 44.6 years, and 66.4% were male. The proportion of African Americans was significantly higher in the youngest age group (<50 years: 6.8% vs 50-79 years: 3.5%, P = .002; vs ≥80 years: 3.5%, P = .013). More bypasses were done for claudication than acute limb ischemia in patients aged <50 years (33.3% vs 11.4%). More vein grafts were used vs prosthetic (<50 years: 72.1% vs 50-79 years: 65.9%, P = .024; vs ≥80 years: 62.6%, P = .002). Fewer concomitant proximal procedures were performed compared with the older groups (<50 years: 37.7% vs 50-79 years: 51.1%, P < .001; vs ≥80 years: 39.5%, P = .045). More young patients returned to the operating room within their initial hospitalization for early graft thrombosis (<50 years: 5.6% vs 50-79 years: 2.9%, P = .001; vs ≥80 years: 2.4%, P = .009) and revision (<50 years: 4.7% vs 50-79 years: 2.2%, P = .012; vs ≥80 years: 1.4%, P = .002) compared with the older patients. Overall, MALE-free survival was similar across age groups (P = .323), as were patency and amputation rates. When considering only patients with CLI, MALE-free survival in the youngest patients was again similar (P = .171) but with significantly more major amputations at 1 year (P = .022).

CONCLUSIONS

For patients aged <50 undergoing infrainguinal bypass surgery, this large series demonstrates similar overall medium-term graft-related outcomes compared with older cohorts. Further, although the youngest patients with CLI have similar MALEs, their amputation rates are higher than in older cohorts.

Implementation of a pilot accountable care organization payment model and the use of discretionary and nondiscretionary cardiovascular care

BACKGROUND

Accountable care organizations (ACOs) seek to reduce growth in healthcare spending while ensuring high-quality care. We hypothesized that accountable care organization implementation would selectively limit the use of discretionary cardiovascular care (defined as care occurring in the absence of indications such as myocardial infarction or stroke), while maintaining high-quality care, such as nondiscretionary cardiovascular imaging and procedures.

METHODS AND RESULTS

The intervention group was composed of fee-for-service Medicare patients (n=819 779) from 10 groups participating in a Medicare pilot accountable care organization, the Physician Group Practice Demonstration (PGPD). Matched controls were patients (n=934 621) from nonparticipating groups in the same regions. We compared use of cardiovascular care before (2002-2004) and after (2005-2009) PGPD implementation, studying both discretionary and nondiscretionary carotid and coronary imaging and procedures. Our main outcome measure was the difference in the proportion of patients treated with imaging and procedures among patients of PGPD practices compared with patients in control practices, before and after PGPD implementation (difference-in-difference). For discretionary imaging, the difference-in-difference between PGPD practices and controls was not statistically significant for discretionary carotid imaging (0.17%; 95% confidence interval, -0.51% to 0.85%; P=0.595) or discretionary coronary imaging (-0.19%; 95% confidence interval, -0.73% to 0.35%; P=0.468). Similarly, the difference-in-difference was also minimal for discretionary carotid revascularization (0.003%; 95% confidence interval, -0.008% to 0.002%; P=0.705) and coronary revascularization (-0.02%; 95% confidence interval, -0.11% to 0.07%; P=0.06). The difference-in-difference associated with PGPD implementation was also essentially 0 for nondiscretionary cardiovascular imaging or procedures.

CONCLUSION

Implementation of a pilot accountable care organization did not limit the use of discretionary or nondiscretionary cardiovascular care in 10 large health systems.

Transabdominal open abdominal aortic aneurysm repair is associated with higher rates of late reintervention and readmission compared with the retroperitoneal approach

OBJECTIVE

Limited data exist comparing the transabdominal and retroperitoneal approaches to open abdominal aortic aneurysm (AAA) repair, especially late mortality and laparotomy-related reinterventions and readmissions. Therefore, we compared long-term rates of mortality, reintervention, and readmission after open AAA repair through a transabdominal compared with a retroperitoneal approach.

METHODS

We identified all patients in the Vascular Quality Initiative (VQI) undergoing open AAA repair from 2003 to 2015. Patients with rupture or supraceliac clamp were excluded. We used the VQI linkage to Medicare to ascertain rates of long-term outcomes, including rates of AAA-related and laparotomy-related (ie, hernia, bowel obstruction) reinterventions and readmissions. We used multivariable Cox regression to account for differences in comorbidities, aneurysm details, and operative characteristics.

RESULTS

We identified 1282 patients in the VQI with linkage to Medicare data, 914 (71%) who underwent a transperitoneal approach and 368 (29%) who underwent a retroperitoneal approach. Patients who underwent a retroperitoneal approach were slightly more likely to have preoperative renal insufficiency but were otherwise similar in terms of demographics and comorbidities. They more often had a clamp above at least one renal artery (61% vs 36%; P < .001) and underwent concomitant renal revascularization (9.5% vs 4.3%; P < .001). Patients who underwent a transabdominal approach more often presented with symptoms (14% vs 9.0%; P < .01) and had a femoral distal anastomosis (15% vs 7.1%; P < .001). There was no difference in 5-year survival (62% vs 61%; log-rank, P = .51). However, patients who underwent a transabdominal approach experienced higher rates of repair-related reinterventions and readmissions (5-year: 42% vs 34%; log-rank, P < .01), even after adjustment for demographic and operative differences (hazard ratio, 1.5; 95% confidence interval, 1.1-1.9; P < .01).

CONCLUSIONS

A transabdominal exposure for AAA repair is associated with higher rates of late reintervention and readmission than with the retroperitoneal approach, which should be considered when possible in operative decision-making.

Factors affecting operative time and outcome of carotid endarterectomy in the Vascular Quality Initiative

OBJECTIVE

Prior studies have suggested a relationship between operative (Op) time and outcome after major vascular procedures. This study analyzed factors associated with Op time and outcome after carotid endarterectomy (CEA) in the Vascular Quality Initiative (VQI) registry.

METHODS

Elective, primary CEAs without high anatomic risk or concomitant procedures from 2012 to 2015 in the VQI were analyzed (N = 26,327, performed by 1188 surgeons from 249 centers). Multivariable analysis was used to identify patient, procedure, and surgeon factors associated with Op time and major adverse events (MAEs), categorized as either technical (ipsilateral stroke, cranial nerve injury, reoperation) or cardiac (myocardial infarction, congestive heart failure, dysrhythmia requiring treatment, surgical site infection, and death).

RESULTS

The mean CEA Op time in the VQI was 114 minutes, with the mean Op time for individual surgeons ranging from 37 to 305 minutes. Procedural factors and the surgeon's volume were responsible for much of the variation in overall Op time (patient factors that reflected demographics and comorbidities each added 5.9 to 6.8 minutes; procedural factors, such as patch angioplasty and completion duplex ultrasound, each added 5.5 to 16.4 minutes; the lowest quartile of the surgeon's annual case volume added 24 minutes). Chi-pie analysis demonstrated that patient factors accounted for 17% of variability in Op time; procedural factors, 44%; and the surgeon's annual volume, 39%. Increasing Op time was highly associated with increased rates of MAEs (P < .001 for cardiac, technical, and death rates). Based on hierarchical multiple logistic regression, cardiac complications were independently associated with increased Op time (comparing surgeons in highest quartile of Op time with those in the lowest: odds ratio, 2.16 for cardiac MAE; 95% confidence interval, 1.59-2.95; P < .001) but not with the surgeon's annual volume. Technical complications were independently associated with a surgeon's low volume (comparing surgeons with the highest annual case volume by quartile against the lowest: odds ratio, 1.25 for technical MAE; 95% confidence interval, 1.06-1.48; P < .001) but not with Op time.

CONCLUSIONS

Op time for elective, primary CEAs varies substantially across surgeons in the VQI. Increased Op time is associated with a surgeon's lower annual CEA volume in addition to patient variables and techniques employed. Cardiac complications after CEA are associated with longer Op time, whereas technical complications are associated with a surgeon's low annual volume.

Using vascular quality initiative as a platform for organizing multicenter, prospective, randomized clinical trials: OVERPAR trial

BACKGROUND

We describe the organization of a prospective, randomized, multicenter trial comparing the effectiveness of open popliteal artery aneurysm repair (OPAR) and endovascular popliteal artery aneurysm repair (EPAR) of asymptomatic popliteal artery aneurysms (PAAs) as an example for how to use the Vascular Quality Initiative (VQI) framework. Given that many centers participate in the VQI, this model can be used to perform multicenters' prospective trials on very modest budget.

METHODS

VQI prospectively collects data on many vascular procedures. These data include many important perioperative, intraoperative, and postoperative details regarding both patients and their procedures. We describe a study where minimal changes to the collected data by participating centers can provide level-1 evidence regarding a significant clinical question. Data will be collected using modified VQI forms within the existing VQI data reporting structure. We plan to enroll 148 patients with asymptomatic PAAs into the open and endovascular surgery cohorts. Patients from participating VQI centers will be randomized 1:1 to either OPAR or EPAR and will be followed for an average of 2.5 years. Our primary hypothesis is that major adverse limb event-free survival is lower in the EPAR cohort and that EPAR is associated with more secondary interventions, improved quality of life, and decreased length of stay. The budget for this trial is fixed at $10,000/year for the course of the study, and the trial is judged to be feasible because of the functionality of the VQI platform.

CONCLUSIONS

Using the existing VQI infrastructure, Open versus Endovascular Repair of Popliteal Artery Aneurysm will provide level 1 data for PAA treatment on a modest budget. The proposed trial has an adequately powered comparative design that will use objective performance goals to describe limb-related morbidity and procedural reintervention rates.

The impact of frequent cystoscopy on surgical care and cancer outcomes among patients with low-risk, non-muscle-invasive bladder cancer

BACKGROUND

Surveillance recommendations for patients with low-risk, non-muscle-invasive bladder cancer (NMIBC) are based on limited evidence. The objective of this study was to add to the evidence by assessing outcomes after frequent versus recommended cystoscopic surveillance.

METHODS

This was a retrospective cohort study of patients diagnosed with low-risk (low-grade Ta (AJCC)) NMIBC from 2005 to 2011 with follow-up through 2014 from the Department of Veterans Affairs. Patients were classified as having undergone frequent versus recommended cystoscopic surveillance (>3 vs 1-3 cystoscopies in the first 2 years after diagnosis). By using propensity score-adjusted models, the authors estimated the impact of frequent cystoscopy on the number of transurethral resections, the number of resections without cancer in the specimen, and the risk of progression to muscle-invasive cancer or bladder cancer death.

RESULTS

Among 1042 patients, 798 (77%) had more frequent cystoscopy than recommended. In adjusted analyses, the frequent cystoscopy group had twice as many transurethral resections (55 vs 26 per 100 person-years; P < .001) and more than 3 times as many resections without cancer in the specimen (5.7 vs 1.6 per 100 person-years; P < .001). Frequent cystoscopy was not associated with time to progression or bladder cancer death (3% at 5 years in both groups; P = .990).

CONCLUSIONS

Frequent cystoscopy among patients with low-risk NMIBC was associated with twice as many transurethral resections and did not decrease the risk for bladder cancer progression or death, supporting current guidelines.