Postprandial silent ischaemia following a fatty meal in patients with recently diagnosed coronary artery disease

Abstract

Silent myocardial ischaemia (SI) is recognised as an important prognostic factor in patients with coronary artery disease (CAD). Postprandial angina is related to severity of CAD. The effect of postprandial metabolic changes in the pathogenesis of SI is unclear. We studied the postprandial changes in glucose, insulin and triglyceride, and non-esterified fatty acids (NEFA) in relation to postprandial SI and exercise capacity, in patients with CAD. Forty elderly volunteers (63 ± 1 years) mean age ± s.e.m., with a history of angina were selected on the basis of a Rose questionnaire and a positive exercise stress test (modified Bruce protocol). The test meal contained 45% fat. The meal was consumed at 9.00 am and hourly blood samples were taken for glucose, insulin, triglyceride and NEFA. Continuous Holter monitoring for SI was conducted using a Spacelabs 2000 monitor. Twenty-five percent of the subjects had episodes of silent ischaemia. Postprandial glucose, insulin, triglyceride, and NEFA were not significantly different in the patients with SI (group 1, n = 10) compared with those without SI (group 2, n = 30). The mean exercise time was 6.1 ± 0.8 min in group 1 compared with 6.8 ± 0.5 minutes in group 2 (P = 0.48). The time to onset of ST depression during exercise test was also not significantly different in the two groups. The occurrence of postprandial SI cannot be related to changes in plasma levels of glucose, triglyceride, insulin, and NEFA. The explanation is not apparent from this study but may relate to a haemodynamic changes such as mesenteric steal.