Hospital vascular surgery volume and procedure mortality rates in California, 1982-1994

Purpose: Little is known about the long-term growth and outcomes of vascular surgery procedures over time. Trends in the use of three major vascular surgery procedures by a general population-lower extremity arterial bypass (LEAB), carotid endarterectomy (CEA), and abdominal aortic aneurysm repair (AAA)-are described. The extent to which these procedures are being performed in low-, moderate-, and high-volume hospitals is examined. Methods: California hospital discharge records for LEAB, CEA, AAA, lower extremity angioplasty, coronary angioplasty, and coronary bypass surgery (CABG) were studied in all non-federal hospitals between 1982 and 1994. The data were age- and sex-adjusted to describe procedure growth. In-hospital mortality rates for LEAB, CEA, and AAA are related to overall hospital procedure volume, using logistic regression to control for risk factors and time trends. Results: Growth in the number of vascular procedures performed in California was modest between 1982 and 1994, with no age-adjusted growth. Lower extremity angioplasty grew considerably in the 1980s and has since plateaued. Annual in-hospital death rates declined for all procedures except ruptured AAA. Comparing the two 5-year periods of 1982-1986 and 1990-1994, in-hospital death rates decreased from 4.2% to 3.3% for LEAB, from 9.2% to 6.2% for unruptured AAA, and from 1.6% to 1.0% for CEA (p < 0.0001). The odds of dying for patients treated in high-volume hospitals for LEAB and CEA procedures compared with patients treated in hospitals performing fewer than 20 procedures in a year were 66.7% (p = < 0.0001) and 66.1% (p < 0.0001), respectively. For patients with ruptured and unruptured AAA procedures, the odds of dying in hospitals with at least 50 AAA procedures in a year were 49.1% (p < 0.0001) and 83.8% (p = 0.016), respectively, compared with the odds of dying in low-volume hospitals. Conclusions: In-hospital mortality rates for CEA, LEAB, and unruptured AAA have been significantly decreasing over time. Mortality is inversely related to hospital volume and directly related to patient age and emergency status. Mortality trends over time for ruptured AAA remains unchanged; however, mortality is less in high-volume hospitals. Coronary angioplasty (PTCA) has not had an impact on rates for LEAB.