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In-hospital mortality is similar for cardiac surgery patients treated at either medium- or high-volume hospitals

Hospitals that perform a high volume of cardiac surgeries (400 or more cases per year) are considered to have better quality of care and patient outcomes than hospitals that perform fewer such surgeries. However, requiring a minimum hospital surgery volume may no longer be an appropriate way to improve quality of cardiac care, according to a recent study. The researchers found no evidence of higher in-hospital deaths in patients undergoing coronary angioplasty at medium-volume hospitals (200 to 299 cases per year) compared with patients treated at high-volume hospitals.

The 400 volume threshold was based on data in the late 1980s and early 1990s that identified increased mortality risk for patients treated at hospitals that performed fewer than 400 coronary angioplasties per year. In the past 5 to 10 years, however, there have been notable changes in angioplasty practice, including the adoption and widespread use of stents (scaffold-like mesh tubes that keep arteries propped open following angioplasty to allow free blood flow), new medications such as glycoprotein IIb/IIIa inhibitors, and an increase in the overall use of angioplasty, explains Andrew J. Epstein, M.P.P., of the Department of Health Care Systems, Wharton School of Business. His work was supported in part by the Agency for Healthcare Research and Quality (National Research Service Award training grant T32 HS00009).

Dr. Epstein and his colleagues retrospectively analyzed AHRQ's Nationwide Inpatient Sample (NIS) hospital discharge database to evaluate in-hospital deaths among 362,748 patients who underwent coronary angioplasty between 1998 and 2000 at low-(5 to 199 cases per year), medium-, high-, and very high- (1,000 cases or more per year) volume hospitals. Crude in-hospital mortality rates were 2.56 percent in low-volume hospitals (21 percent higher than high-volume hospitals, after adjustment for patient characteristics). Yet, mortality rates were similar among medium-volume (1.83 percent), high-volume (1.64 percent), and very high-volume hospitals (1.36 percent).

See "Hospital percutaneous coronary intervention volume and patient mortality, 1998 to 2000: Does the evidence support current procedure volume minimums?" by Dr. Epstein, Saif S. Rathore, M.P.H., Kevin G. Volp, M.D., Ph.D., and Harlan M. Krumholz, M.D., S.M., F.A.C.C., in the May 19, 2004, Journal of the American College of Cardiology 43(10), pp. 1755-1762.

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