The clinical significance of somatic pain tolerance in patients with coronary artery disease

Background: This study was undertaken to evaluate the clinical and prognostic significance of individual differences in somatic pain tolerance in patients with coronary disease. Methods: Two hundred seventy-one patients with a recent acute coronary event underwent pain tolerance testing using the tourniquet test. Baseline ambulatory and exercise electrocardiography, and stress thallium scintigraphy were performed, and patients were followed prospectively for a mean of 33 ± 8 months for the occurrence of unstable angina, nonfatal myocardial infarction (MI), or cardiac death. Results: Patients with lower tolerance to somatic pain were significantly older (P = 0.001), had more clinical angina (P = 0.04), and on multivariate analysis had poorer exercise tolerance (P = 0.002) than those with higher pain tolerance. Low and high pain tolerance patients demonstrated similar degrees of myocardial ischemia on noninvasive testing and had similar cardiac event rates (death, nonfatal MI, or unstable angina) during the follow-up period. Conclusions: Despite demonstrating a similar frequency of myocardial ischemia and similar prognosis as patients with high pain tolerance, individuals with low pain tolerance were more likely to experience clinical symptoms and functional impairment, providing evidence that individual differences in somatic pain tolerance influence the symptomatic expression of coronary disease.