Volume Standards for Open Abdominal Aortic Aneurysm Repair Are Not Associated With Improved Clinical Outcomes.

BACKGROUND: Volume-outcome relationships exist for many complex surgical procedures, prompting institutions to adopt surgical volume standards for credentialing. The current Leapfrog Group Hospital volume standard for open abdominal aortic aneurysm repair (OAR) is 15 per year. However, this is primarily based on data from the 1990s and may not be appropriate given the dramatic decline in OAR. We sought to quantify the proportion of hospitals meeting volume standards, the difference in perioperative outcomes between low-volume and high-volume hospitals, and the potential travel burden of volume credentialing on patients. METHODS: We identified Medicare beneficiaries for individuals aged ≥65 years undergoing OAR in 2013-2014. Hospital "all-payer" annual volume was estimated based on the national proportion of patients undergoing OAR covered by Medicare in the Vascular Quality Initiative. Hospital annual OAR volume was characterized as <5/year, 5-9/year, 10-14/year, and ≥15/year (high volume). Adjusted rates of postoperative morbidity, reoperation, failure to rescue, and mortality in 2014 were compared across volume cohorts. Distance between patients' home zip code and high-volume hospitals was calculated. RESULTS: A total of 21,191 OARs were performed at 1,445 hospitals between 2013 and 2014. The average hospital OAR annual volume was 7.8 (standard deviation [SD] ± 9.3) with a median of 4.5. Among the 1,445 hospitals, only 190 (13.1%) performed ≥15 OARs per year whereas 756 hospitals (53.3%) performed <5 per year. Among patients who underwent OAR in 2014, 5,395 (53.3%) received care at a hospital that performed <15 per year. There was no difference in complication, reoperation, or failure to rescue rates between high-volume and low-volume hospitals. Mortality did not significantly differ among OAR volume cohorts. Hospitals performing <5 OARs per year had a mortality rate of 5.7% compared with 5.6% at high-volume hospitals (P = 0.817). One-quarter of patients who received care at a low-volume hospital would have had to travel more than 60 miles to reach a high-volume hospital. CONCLUSIONS: By conservative estimates, only 13% of hospitals performing OAR meet current volume standards. Triaging all patients to high-volume hospitals would require shifting over 5,000 patients annually with no associated improvement in perioperative outcomes. Implementation of the current OAR hospital volume standard may significantly burden patients and hospitals without improving surgical outcomes.

Predictors of compliance with surveillance after endovascular aneurysm repair and comparative survival outcomes.

OBJECTIVE: Although imaging surveillance is mandatory for all patients after endovascular aneurysm repair (EVAR), many patients are not compliant with follow-up. We sought to determine predictors of compliance with EVAR surveillance and to examine how compliance with current surveillance protocols correlates with survival. METHODS: We analyzed 188 patients who underwent EVAR at our institution for infrarenal abdominal aortic aneurysms (AAAs) between 2001 and 2011. The primary end point was compliance with post-EVAR surveillance recommendations. Univariate analysis included patient demographics and socioeconomic information, AAA characteristics, EVAR hospital course variables, late complications and secondary interventions, length of follow-up, smoking status, family history of AAA, driving distances, primary care providers, and medical comorbidities. Mortality was determined by the Social Security Death Index. Multinomial logistic regressions were fit to identify independent predictors of compliance. Survival plots were generated with the Kaplan-Meier method and compared with the log-rank test. Univariate and multivariate Cox regression analysis was used to determine effect of compliance on survival after adjusting for confounders. RESULTS: Of 188 patients, 89 (47.3%) were 100% compliant with follow-up visits and imaging, 21 (11.1%) were moderately compliant by missing appointments, and 78 (41.4%) were lost to follow-up completely. Overall median age was 74 years, and 81.9% of patients were male. Late complications occurred in 77 patients (40.9%), secondary interventions were performed in 32 patients (17%), and 5-year mortality was 21.2%. Mean follow-up interval was >40 months for 100% compliant and moderately compliant patients and <20 months for those lost to follow-up (P < .0001). In adjusted analysis, late complications (odds ratio [OR], 2.71; 95% confidence interval [CI], 1.32-5.55; P = .007), absence of social work consultation (OR, 2.43; 95% CI, 1.12-5.27; P = .024), and family history of AAA (OR, 2.67; 95% CI, 1.06-6.75; P = .037) were associated with 100% compliance, whereas shorter driving distances (P = .051) and shorter hospital stay (P = .056) approached significance. Transient ischemic attack or stroke (OR, 3.59; 95% CI, 1.18-10.91; P = .024) was the only variable independently associated with moderate compliance. Compared with patients lost to follow-up, 100% compliant patients had worse survival (log-rank test, P = .033), whereas moderately compliant patients' survival was not significantly different (log-rank test, P = .149). In adjusted Cox regression analysis, 100% compliant patients had decreased survival duration (rate ratio, 2.67; 95% CI, 1.18-6.06; P = .018) compared with those lost to follow-up. CONCLUSIONS: Follow-up surveillance is incomplete for more than half of patients who undergo EVAR at our institution, and patient compliance can be predicted by covariates mentioned before. Compliance with current surveillance regimens does not confer a survival benefit. Further research individualizing surveillance protocols based on risk level of late complications and noncompliance and prospective studies examining resulting survival benefits of compliance are warranted.

Endovascular Skills for Trauma and Resuscitative Surgery (ESTARS) course: curriculum development, content validation, and program assessment.

BACKGROUND: The management of hemorrhage shock requires support of central aortic pressure including perfusion to the brain and heart as well as measures to control bleeding. Emerging endovascular techniques including resuscitative endovascular balloon occlusion of the aorta serve as potential lifesaving adjuncts in this setting. The Endovascular Skills for Trauma and Resuscitative Surgery (ESTARS) course was developed to provide fundamental endovascular training for trauma surgeons. METHODS: ESTARS 2-day course incorporated pretest/posttest examinations, precourse materials, lectures, endovascular and open vascular instruments, Vascular Intervention System Trainer endovascular simulator, and live animal laboratories for training and testing. Curriculum included endovascular techniques for trauma; review of wires, sheaths, and catheters; as well as regional vascular injury management. Animal laboratories integrated arterial access, angiography, coil embolization, resuscitative endovascular balloon occlusion of the aorta, control of iliac artery injury, and vascular shunt placement. Students completed a knowledge test (precourse/postcourse) and a summative skills assessment. The test measured knowledge and judgment in vascular injury management as defined in the course objectives. Vascular Intervention System Trainer and animal laboratory were used for final examinations. Subjective performance was graded by expert observers using a global assessment scale and performance metrics. RESULTS: Four pilot ESTARS courses were completed, with four participants each. Knowledge and performance significantly improved after ESTARS. Mean test examination scores increased by 77% to 85%, with a mean change of 9 percentage points [paired t (15) = 7.82, p < 0.0001]. The test was unidimensional (Cronbach's α = 0.67). Technical skill significantly improved for both endovascular simulation and live animal laboratory examinations. All participants passed the live animal laboratory practical examination. CONCLUSION: The ESTARS curriculum is effective at teaching a basic set of endovascular skills for resuscitation and hemorrhage control to trauma surgeons. ESTARS was confirmed as a stepwise and hierarchical curriculum demonstrating measurable improvements in performance metrics and should serve as a model for future competency-based structured training in endovascular trauma skills.

Specialized vascular floors after open aortic surgery: cost containment while preserving quality outcomes.

BACKGROUND: Postoperative care of open abdominal aortic surgery (OAAS) traditionally involves the intensive care unit (ICU). We hypothesized that in patients without an indication for postoperative ICU admission, admission to a specialized vascular floor unit (hemodynamic monitoring, 2:1 nursing) offers cost savings to both payer and institution without compromising care. METHODS: The electronic medical record was used to collect perioperative data for patients who underwent OAAS between July 2007 and July 2011. The university's cost accounting system provided information on revenue, total margin, and professional billing. Patients with ICU indications (spinal drain, Swan-Ganz monitoring, vasopressors, intubation, or blood product resuscitation) were excluded. Comparative cost and outcome analysis was performed on vascular ward and ICU admissions using the Fisher's exact test for dichotomous categorical variables and the Student's t-test for continuous variables. Long-term survival comparison was calculated using Kaplan-Meier survival estimates. RESULTS: One hundred thirty of 215 patients were included for analysis (85 excluded, 51 floor, 79 ICU). Perioperative data amongst the floor and ICU cohorts were similar. Day of operation professional billing fees were comparable (ICU $13,365 vs. floor $12,626; P = 0.18); however, postoperative professional fees were significantly higher in the ICU cohort (ICU $3,258 vs. floor $2,101; P = 0.001) primarily because of intensivist billing. The hospital generated an average of 8.7% more revenue from the ICU cohort (ICU $37,770 vs. floor $34,756; P = 0.023). This was offset by greater expenses in the ICU cohort (ICU $30,756 vs. floor $25,144; P = 0.02), yielding a hospital profit margin of 107.5% favoring floor admission (ICU $2,858 vs. floor $5,931; P = 0.19). Duration of stay was similar (ICU 8.0 days vs. floor 7.8 days; P = 0.86). Kaplan-Meier survival analysis was not significantly different between cohorts (ICU 10.1%, median follow-up, 1,070 days vs. floor 0%, median follow-up, 405 days; P = 0.13). CONCLUSIONS: Postoperative admission to the ICU is not always necessary after OAAS. Specialized vascular floors offer a financial savings to both payer and institution, which allows for simultaneous cost containment while preserving quality outcomes.

The complete management of extremity vascular injury in a local population: a wartime report from the 332nd Expeditionary Medical Group/Air Force Theater Hospital, Balad Air Base, Iraq.

BACKGROUND: Although the management of vascular injury in coalition forces during Operation Iraqi Freedom has been described, there are no reports on the in-theater treatment of wartime vascular injury in the local population. This study reports the complete management of extremity vascular injury in a local wartime population and illustrates the unique aspects of this cohort and management strategy. METHODS: From September 1, 2004, to August 31, 2006, all vascular injuries treated at the Air Force Theater Hospital (AFTH) in Balad, Iraq, were registered. Those in noncoalition troops were identified and retrospectively reviewed. RESULTS: During the study period, 192 major vascular injuries were treated in the local population in the following distribution: extremity 70% (n=134), neck and great vessel 17% (n=33), and thoracoabdominal 13% (n=25). For the extremity cohort, the age range was 4 to 68 years and included 12 pediatric injuries. Autologous vein was the conduit of choice for these vascular reconstructions. A strict wound management strategy providing repeat operative washout and application of the closed negative pressure adjunct was used. Delayed primary closure or secondary coverage with a split-thickness skin graft was required in 57% of extremity wounds. All patients in this cohort remained at the theater hospital through definitive wound healing, with an average length of stay of 15 days (median 11 days). Patients required an average of 3.3 operations (median 3) from the initial injury to definitive wound closure. Major complications in extremity vascular patients, including mortality, were present in 15.7% (n=21). Surgical wound infection occurred in 3.7% (n=5), and acute anastomotic disruption in 3% (n=4). Graft thrombosis occurred in 4.5% (n=6), and early amputation and mortality rates during the study period were 3.0% (n=4) and 1.5% (n=2), respectively. CONCLUSIONS: To our knowledge, this study represents the first large report of wartime extremity vascular injury management in a local population. These injuries present unique challenges related to complex wounds that require their complete management to occur in-theater. Vascular reconstruction using vein, combined with a strict wound management strategy, results in successful limb salvage with remarkably low infection, amputation and mortality rates.

Diffusion of new technology for the treatment of renovascular hypertension in the United States: surgical revascularization versus catheter-based therapy, 1988-2001.

BACKGROUND: Trends in the management of renovascular hypertension were evaluated by using a representative national database to determine whether a shift in treatment technology and outcomes has occurred. METHODS: Clinical information regarding the treatment of renovascular hypertension in 5433 patients from 1988 to 2001 was derived from the Nationwide Inpatient Sample (NIS) database. Patients were classified into 3 groups: combined aortic and renal revascularization, isolated renal revascularization, and catheter-based procedures (angioplasty with or without stenting). Population-based trends were determined by using sampling weights for each year to estimate the total number of each intervention in the United States. Outcomes were compared using multivariate logistic regression analysis for risk-adjustment. RESULTS: A 73% decrease in combined aortic and renal revascularizations ( P = .033) and a 56% decrease in isolated renal revascularizations ( P < .001) occurred during the study period. Catheter-based procedures have increased 173% from 0.4 to 1.1 procedures per 100,000 adults during this same time period ( P < .001). Predictors favoring catheter-based treatment were admission acuity, increasing age, nonwhite race, and high socioeconomic status. Predictors of mortality for all 3 treatment groups included increasing age, emergent admission, and nonwhite race. CONCLUSIONS: A significant change in the management of patients with renovascular hypertension has occurred, with a shift towards less invasive catheter-based interventions. A better understanding of the diffusion of this technology in the treatment of individuals with renovascular hypertension will influence the training and distribution of future vascular specialists responsible for these patients.

Diffusion of new technology in health care: the case of aorto-iliac occlusive disease.

BACKGROUND: The objective of the current study was to characterize temporal trends in the treatment of aorto-iliac occlusive disease (AIOD) and the impact of the introduction of less invasive therapy on overall intervention rates. METHODS: Patients with diagnostic codes for AIOD, and procedure codes for aortofemoral bypass (AFB) or iliac artery angioplasty and stenting were selected from the Nationwide Inpatient Sample for 1996 to 2000. Utilization rates of both intervention types were determined. Outcome variables including in-hospital mortality and duration of stay were assessed. RESULTS: The rate of iliac artery angioplasty and stenting increased 850%, from 0.4 to 3.4 cases per 100,000 adults (P <.001). The rate of AFB declined 15.5%, from 5.8 to 4.9 cases per 100,000 adults (P <.005). Older age, white race, and higher-income patients were more likely to undergo angioplasty and stenting. AFB had a higher mortality rate, longer duration of stay, and higher hospital charges compared to angioplasty and stenting. CONCLUSIONS: Iliac artery angioplasty and stenting has rapidly gained a large market share in the treatment of AIOD. Acceptable clinical outcomes have likely lowered the threshold for treatment and contributed to the rapid diffusion of this technology for the treatment of AIOD.