Patients with aortic stenosis: Cardiac complications in non-cardiac surgery
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PURPOSE: To reassess the risk of patients with aortic stenosis (AS) undergoing non-cardiac surgery. METHODS: Following institutional approval, a retrospective chart audit of all patients with AS who underwent non-cardiac surgery in Hamilton between 1992 and 1994 was performed. For each AS case, a matching control was randomly selected. Data pertaining to pre-operative cardiac risk factors, intra-operative, and post-operative management were recorded. Complications were defined as the onset of congestive heart failure (CHF), myocardial infarction (MI), or dysrhythmias requiring cardioversion within seven post-operative days; unplanned or prolonged intensive care unit (ICU) stay due to cardiac cause; and cardiac death. Categorical data were compared using discordant data pairs and binomial distribution, with theta = 0.5. Parametric data were compared using students' t test. All comparisons were two-tailed, with alpha < 0.05 considered significant. RESULTS: 55 patients (32 male, 23 female, mean age 73 yr) with AS (mean aortic valve area 0.9 cm2) were studied. Cases and controls were identical for eight of nine pre-operative risk factors. Differences in perioperative management were found. Cardiac complications occurred in five cases and six control patients (P = 1.00). CONCLUSIONS: The current study, involving 55 patients with AS undergoing non-cardiac surgery, showed no difference in the risk of cardiac complications compared with matched controls. However, the intensification of management in the AS patients may have attenuated the risk in this group. The sample size was adequate to detect a fourfold increase in risk.