Institutional volumes and coronary angioplasty outcomes before and after the introduction of stenting.
Background: An increasing number of patients undergoing percutaneous transluminal coronary angioplasty (PTCA) are receiving coronary stents.
Objective: To assess whether the introduction of coronary stenting has changed hospital mortality or same-admission coronary artery bypass grafting (CABG) and whether the hospital's procedure volume affects these outcomes.
Methods: Observational study using hospital claims. Methods: Nonfederal hospitals that performed PTCA in California in 1993 and 1996. Methods: 35,350 patients who underwent PTCA in 1993 (before the introduction of stenting) and 43,040 patients who had PTCA in 1996 (43% of whom received stents). Methods: Hospital stenting volumes for 1996 were divided into terciles; total PTCA procedures per year were categorized as low (< or = 200), medium (201 to 400), or high (> 400). Outcome variables included hospital death and coronary artery bypass grafting (CABG) performed during the same admission. Patients with a principal diagnosis of acute myocardial infarction (AMI) were analyzed separately from those without such a diagnosis.
Results: From 1993 to 1996, the characteristics of patients undergoing PTCA did not change substantially. The use of same-admission CABG decreased by 13% (from 6.0% to 5.2%; P = 0.008) in the AMI group and by 30% (from 3.7% to 2.6%; P < 0.001) in the no-AMI group. Hospital mortality did not change significantly in either group. Procedure volume was not related to hospital mortality. However, rates of same-admission CABG were significantly lower at hospitals with high annual stenting volumes than at low-volume centers (1.3% vs. 2.3% among patients in the no-AMI group; P < 0.001).
Conclusions: Hospital mortality rates after PTCA have not changed considerably since the introduction and diffusion of coronary stenting. However, rates of same-admission CABG have decreased in recent years and are lowest at hospitals with high procedure volumes.