Variation in the elective management of small abdominal aortic aneurysms and physician practice patterns.

OBJECTIVE: Recent vascular societal guidelines have recommended an abdominal aortic aneurysm (AAA) size threshold for elective intervention; however, limited data have documented how well these AAA diameter benchmarks are being met. The objective of this study was to analyze variation in management of AAAs based on diameter and to determine the physician's rationale for intervention on small AAAs in relation to recommended treatment guidelines. METHODS: A retrospective review of a statewide vascular surgery registry of all elective endovascular or open surgical AAA repairs from January 2012 to January 2016 was performed. Patients were dichotomized on the basis of aortic diameter at time of intervention into either guideline size AAAs or small AAAs, which were defined as <5.5 cm in men, <5.0 cm in women, or with growth <1.0 cm/y. An internal review was conducted of all small AAAs to determine the physician's rationale for intervention. The primary outcomes were variation in adherence to recommended treatment guidelines and the physician's rationale for treatment of small AAAs. Risk-adjusted major complication and mortality rates were calculated at 30 days and 1 year using a propensity score matching analysis. RESULTS: Among the 3932 patients who underwent an elective AAA repair, 485 (12.3%) were repaired at diameters smaller than recommended by guidelines. The median AAA size in the small AAA cohort was 5.1 cm (interquartile range, 4.7-5.3 cm) vs 5.6 cm (interquartile range, 5.2-6.1 cm) in the guideline-based group. Percentage of small AAA repairs varied widely between hospitals from 1.4% to 44.4%. The physician's rationale for the majority of early interventions included the patient's anxiety (12.0%), combined aortoiliac occlusive disease (14.8%), aneurysm anatomy (28.2%), and does not adhere to guidelines (30%). The small AAA cohort had no significant difference in the 30-day or 1-year risk-adjusted mortality in comparison to guideline size AAAs. CONCLUSIONS: Despite well-established aortic diameter threshold guidelines, marked variation exists both at the hospital level and in terms of the physician's rationale for the management of elective AAA repairs. These findings demonstrate the challenge of providing uniform care for patients with AAAs despite established guidelines.

The Association of Peri-Procedural Blood Transfusion with Morbidity and Mortality in Patients Undergoing Percutaneous Lower Extremity Vascular Interventions: Insights from BMC2 VIC.

OBJECTIVE: To determine the predictors of periprocedural blood transfusion and the association of transfusion on outcomes in high risk patients undergoing endoluminal percutaneous vascular interventions (PVI) for peripheral arterial disease. METHODS/RESULTS: Between 2010-2014 at 47 hospitals participating in a statewide quality registry, 4.2% (n = 985) of 23,273 patients received a periprocedural blood transfusion. Transfusion rates varied from 0 to 15% amongst the hospitals in the registry. Using multiple logistic regression, factors associated with increased transfusion included female gender (OR = 1.9; 95% CI: 1.6-2.1), low creatinine clearance (1.3; 1.1-1.6), pre-procedural anemia (4.7; 3.9-5.7), family history of CAD (1.2; 1.1-1.5), CHF (1.4; 1.2-1.6), COPD (1.2; 1.1-1.4), CVD or TIA (1.2; 1.1-1.4), renal failure CRD (1.5; 1.2-1.9), pre-procedural heparin use (1.8; 1.4-2.3), warfarin use (1.2; 1.0-1.5), critical limb ischemia (1.7; 1.5-2.1), aorta-iliac procedure (1.9; 1.5-2.5), below knee procedure (1.3; 1.1-1.5), urgent procedure (1.7; 1.3-2.2), and emergent procedure (8.3; 5.6-12.4). Using inverse weighted propensity matching to adjust for confounders, transfusion was a significant risk factor for death (15.4; 7.5-31), MI (67; 29-150), TIA/stroke (24; 8-73) and ARF (19; 6.2-57). A focused QI program was associated with a 28% decrease in administration of blood transfusion (p = 0.001) over 4 years. CONCLUSION: In a large statewide PVI registry, post procedure transfusion was highly correlated with a specific set of clinical risk factors, and with in-hospital major morbidity and mortality. However, using a focused QI program, a significant reduction in transfusion is possible.

The association of perioperative transfusion with 30-day morbidity and mortality in patients undergoing major vascular surgery.

OBJECTIVE: Blood transfusions are common among patients undergoing major vascular surgery. Prior studies suggest an association between blood transfusion and increased morbidity and mortality among patients undergoing cardiac surgery. The predictors of perioperative transfusion and its impact on patients undergoing vascular surgery have been poorly defined. METHODS: We examined data from a large multicenter quality improvement vascular surgical registry of all patients undergoing elective or urgent open peripheral arterial disease procedures, endovascular aneurysm repair, or open abdominal aortic aneurysm (AAA) repair between January 2012 and December 2013. Emergency cases, carotid endarterectomy, and carotid artery stenting were excluded. Univariate and multivariate logistic regression modeling was used to identify predictors of transfusion and association of transfusion with outcomes. All regression models had Hosmer-Lemeshow P > .05 and area under the receiver operating characteristic curve of >0.8, confirming excellent goodness of fit and discrimination. RESULTS: Our study population comprised 2946 patients who underwent open peripheral arterial disease procedures (n = 1744), open AAA repair (n = 175), or endovascular aneurysm repair (n = 1027) at 22 hospitals. The overall transfusion rate was 25%, at a median nadir hemoglobin level of 7.7 g/dL. Independent factors predicting transfusion included female gender (odds ratio [OR], 2.6; 95% confidence interval [CI], 2.1-3.2), nonwhite race (OR, 2.7; 95% CI, 1.4-5.2), preoperative admission status (ie, acute care hospital) (OR, 2.6; 95% CI, 1.3-5.3), preoperative anemia (OR, 4.2; 95% CI, 3.3-5.1), congestive heart failure (OR, 1.4; 95% CI, 1.1-1.9), prior myocardial infarction (OR, 1.3; 95% CI, 1.01-1.6), clopidogrel (OR, 1.4; 95% CI, 1.2-1.8), open AAA repair (OR, 25; 95% CI, 17-39), open bypass (OR, 3.5; 95% CI, 2.7-4.6), and urgent procedures (OR, 1.4; 95% CI, 1.1-1.8). With adjustment for major covariates, perioperative transfusion was independently associated with death (OR, 6.9; 95% CI, 3.2-15), myocardial infarction (OR, 8; 95% CI, 3.7-17), and pneumonia (OR, 7.4; 95% CI, 3.3-17). CONCLUSIONS: Perioperative transfusion in vascular surgical patients is independently associated with increased 30-day morbidity and mortality. Given indeterminate causation, these data suggest the need for a prospective transfusion threshold study in vascular surgical patients.

Vascular function and carotid intimal-medial thickness in children with insulin-dependent diabetes mellitus.

OBJECTIVES: The objective of this study was to evaluate endothelium-dependent vasodilation and carotid intimal-medial thickness (IMT) in children with insulin-dependent diabetes mellitus. BACKGROUND: Diabetes mellitus is an established risk factor for atherosclerosis. Vascular complications of diabetes are not clinically evident in diabetic children. However, preclinical atherosclerosis is more common in young subjects exposed to cardiovascular risk factors. Endothelial function and carotid IMT, known to be abnormal in preclinical atherosclerosis, have not been studied concurrently in a pediatric population exposed to a risk factor for atherosclerosis. METHODS: We studied 31 diabetic teenagers (age 15.0 +/- 2.4 years; duration of diabetes 6.8 +/- 3.9 years) and 35 age-matched healthy children (age 15.7 +/- 2.7 years). Using high-resolution vascular ultrasound, we compared carotid IMT and brachial artery responses to reactive hyperemia (endothelium-dependent vasodilation) and to sublingual nitroglycerin (endothelium-independent vasodilation). RESULTS: There was no difference in baseline brachial artery diameter between the two groups. Endothelium-dependent vasodilation was significantly lower in diabetic children compared with healthy children (4.2 +/- 3.8% vs. 8.2 +/- 4.2%, p < 0.001). There was no difference in endothelium-independent vasodilation (17 +/- 6% vs. 18 +/- 6%, p = NS) or mean carotid IMT between the groups (0.33 +/- 0.05 vs. 0.32 +/- 0.08 mm, p = NS). Endothelium-dependent brachial vasodilation correlated with blood glucose levels (r = 0.58, p = 0.001) and was weakly and inversely related to the duration of diabetes (r = -0.4, p = 0.02), total cholesterol, and low-density lipoprotein cholesterol levels. CONCLUSIONS: Endothelial function is impaired in children with diabetes mellitus within the first decade of its onset and precedes an increase in carotid IMT. The relative timing of these events is important in the evaluation of strategies to prevent progression of atherosclerosis and other vascular complications in this patient population.

Intraoperative insertion of Greenfield filters: lessons learned in a personal series of 152 cases.

The objective of this study was to define outcomes of 151 patients who underwent insertion of 152 Greenfield filters in the operating room by general and vascular surgery residents with supervision by one attending vascular surgeon. Each patient was taken to the operating room for inferior vena cava (IVC) interruption immediately after a vena cavagram was performed. One patient required a subsequent return to the operating room after developing paradoxical arterial embolism from a large venous thromboembolism which was trapped by and spanned both sides of the first IVC filter. In this case a second suprarenal filter was placed at the time of arterial embolectomy. In each of these 152 cases intraoperative venacavography was performed using a mobile C-arm. Complications such as hemothorax, filter misplacement, and vena cava perforation were identified. Late survival was defined using the Social Security Death Index. Of the 151 patients undergoing intraoperative insertion of Greenfield filters there was one hemothorax from attempts at acquiring venous access via percutaneous puncture of the internal jugular vein. This required transfusion but not thoracotomy, and IVC interruption was achieved. A separate patient had insertion of a Greenfield filter into a gonadal vein which required placement of a second filter into the IVC. There was one IVC perforation from a transfemoral filter insertion which required placement of a second filter above this perforation and laparotomy to retrieve the filter and repair the IVC. In one more patient the IVC filter initially failed to open, and a second filter was placed above the first filter. In this experience the misplacement rate was 0.7 per cent and the serious complication rate was 1.3 per cent. None of the patients was adversely affected per se by transfer to the operating room for Greenfield filter insertion. No patient died from filter insertion, but in two cases serious associated complications contributed to the adverse outcomes in these already terminally ill patients. Overall 30-day mortality rate was 6.6 per cent. Late survival was defined as follows: survival at one year after filter insertion was 75 per cent, at 2 years 63 per cent, at 3 years 60 per cent, at 4 years 57 per cent, and at 5 years 54 per cent. Mean survival after filter placement was 4.96 years. We conclude that Greenfield filters can be inserted in the operating room by general and vascular surgery residents with attending supervision with reasonable safety and with a low rate of filter misplacement. The caval perforation and gonadal vein filter misplacement could both have been avoided by use of an over-the-wire filter deployment system, which at the time of these specific complications was not available. Vena cava filter insertion should remain within the scope of practice of surgeons and can be done with reasonable safety under C-arm guidance in the operating room. Use of over-the-wire systems could have helped reduce the likelihood of all but one of the filter-related complications experienced in this series.

Very late survival after vascular surgery.

PURPOSE: The aim of this study was to define very late survival in veterans who routinely underwent preoperative assessment of left ventricular function using radionuclide ventriculography (RNVG) before elective major vascular surgery from 7/84 to 7/88 at one Veterans Affairs Medical Center. METHODS: RNVG defined left ventricular ejection fraction (EF) and determined the presence of ventricular wall motion abnormalities. Patients undergoing elective vascular surgery (n = 310) who had preoperative RNVG were then followed over the years using direct contact, VA administrative databases, and, most recently, the Social Security Death Index. RESULTS: Follow-up was 6.64 +/- 4.62 years (range 0 to 16.2 years). Current survival is 10% (11/107) after carotid surgery, 12% (10/82) after aortic aneurysm repair, 15% (17/111) after extremity reconstruction, and 0% (0/10) after visceral artery reconstruction (ns). There was no statistically significant difference in mortality between the different types of vascular surgery at 30 days or at 1, 5, and 10 years after surgery (ns). Actual survival rates at 5 years after carotid surgery, aneurysm repair, extremity reconstruction, and visceral reconstruction were 55, 61, 59, and 50%, respectively. Stepwise logistic regression analysis was performed which included preoperatively defined cardiovascular risk factors, type of surgery, and results of RNVG. The final regression model indicated that age, diabetes, smoking at the time of surgery, and low EF were independently associated with overall mortality while angina, prior myocardial infarction (MI), and type of operation were not. Mean survival duration with normal EF (>50%) was 7.99 years versus 4.78 years with low EF (P < 0.001). No patient with severe left ventricular dysfunction (EF < or = 35%; n = 39) or who had postoperative cardiac complications (MI, CHF, ventricular arrhythmia; n = 38) survived to the present. CONCLUSIONS: Very late survival after major vascular surgery was related to the presence of diabetes, active smoking at the time of surgery, left ventricular function, and postoperative cardiac complications. Since there was no association of overall mortality with angina or prior MI, an aggressive approach to coronary evaluation in such patients might not alter very late survival.

Variation in death rate after abdominal aortic aneurysmectomy in the United States: impact of hospital volume, gender, and age.

OBJECTIVE: To determine whether high-volume hospitals (HVHs) have lower in-hospital death rates after abdominal aortic aneurysm (AAA) repair compared with low-volume hospitals (LVHs). SUMMARY BACKGROUND DATA: Select statewide studies have shown that HVHs have superior outcomes compared with LVHs for AAA repair, but they may not be representative of the true volume-outcome relationship for the entire United States. METHODS: Patients undergoing repair of intact or ruptured AAAs in the Nationwide Inpatient Sample (NIS) for 1996 and 1997 were included (n = 13,887) for study. The NIS represents a 20% stratified random sample representative of all U.S. hospitals. Unadjusted and case mix-adjusted analyses were performed. RESULTS: The overall death rate was 3.8% for intact AAA repair and 47% for ruptured AAA repair. For repair of intact AAAs, HVHs had a lower death rate than LVHs. The death rate after repair of ruptured AAA was also slightly lower at HVHs. In a multivariate analysis adjusting for case mix, having surgery at an LVH was associated with a 56% increased risk of in-hospital death. Other independent risk factors for in-hospital death included female gender, age older than 65 years, aneurysm rupture, urgent or emergent admission, and comorbid disease. CONCLUSIONS: This study from a representative national database documents that HVHs have a significantly lower death rate than LVHs for repair of both intact and ruptured AAA. These data support the regionalization of patients to HVHs for AAA repair.