Revascularization use and survival outcomes after cardiac catheterization in British Columbia and Alberta

Alberta and British Columbia have comprehensive cardiac databases that provide detailed demographic, clinical and procedural data, including coronary anatomy, on all patients undergoing cardiac catheterization.

To examine the baseline clinical characteristics of patients undergoing cardiac catheterization, describe the use of revascularization treatments (percutaneous coronary intervention [PCI] and coronary artery bypass grafting [CABG]) following catheterization, and describe survival after cardiac catheterization, stratified by treatment strategy received and proposed, using cardiac databases from Alberta and British Columbia.

All patients between 20 and 105 years of age, admitted to hospital for their first coronary angiography between April 1, 1995, and March 31, 2001, with angiographic evidence of coronary disease were included in the study. Procedure volumes, baseline characteristics and therapy received within one year of cardiac catheterization are described by province. Stepwise, multivariate logistic regression analysis was used to model determinants of the revascularization modality. Kaplan-Meier curves of one-year survival after index cardiac catheterization were estimated for the therapy received (Alberta and British Columbia) and the therapy proposed (British Columbia only).

Patients were predominantly men (70%), commonly presented with two- or three-vessel disease, and frequently had hypertension, a history of myocardial infarction and dyslipidemia. Within one year of catheterization, 21% to 26% underwent CABG and 32% to 42% underwent PCI. Emergency or urgent status at the time of catheterization was associated with receiving PCI, while three-vessel and left main disease were associated with receiving CABG. Patients who did not undergo revascularization within one year (presumed medical therapy) had the lowest one-year survival rate (93.4%; 95% CI 92.1% to 94.7%); this group comprised patients receiving medical therapy as proposed (one-year survival rate of 95.7%, 95% CI 94.6% to 96.8%), as well as patients receiving medical therapy at variance with the proposal for revascularization (84.6%; 95% CI 80.5% to 88.9%).

Between 53.1% and 67.5% of patients presenting for cardiac catheterization undergo revascularization within one year. Urgent status increased the probability of PCI, and anatomy (ie, three-vessel and left main) increased the probability of CABG. Patients not undergoing proposed revascularization by one year had poorer outcomes, in contrast with those proposed for medical therapy, who had excellent outcomes.