Relationship between blood pressure and cardiac events in patients with a healed myocardial infarction

This study investigated the association between blood pressure (diastolic [DBP] and systolic [SBP]) and cardiac events in a total of 6,602 patients with a healed myocardial infarction (MI) (5,320 men, 1,282 women; mean age, 58.9 +/- 10.4 years), including in-patients and out-patients, from January 1986 to January 1999. The primary endpoints (cardiac events) were recurrent MI (fatal and non-fatal), death from congestive heart failure, or sudden death. The total number of cardiac events was 195 (3.0%) and the incidences of the 3 cardiac events were compared among the 3 DBP groups (DBP low group, < 70 mmHg; DBP middle group, 70-89 mmHg; DBP high group, greater than or equal to 90 mmHg). There were some significant differences in the characteristics of patients among the 3 groups, but no significant difference in cardiac death and total mortality was found among the 3 groups. Cardiac events occurred in 59 of 1,780 patients (3.3%, 33.9/1,000 person years) in the DBP low group, tended to be reduced in number in the DBP middle group (87 of 3,549 patients 2.5%, 21.4/1,000 person years) and were slightly increased in number in the DBP high group (24 of 642 patients 3.7%, 35.2/1,000 person years). Although this correlation between BP and cardiac events appears to be J-shaped, because there is no statistically significant difference in the rate of cardiac events among the 3 groups, we conclude that DBP does not influence the occurrence of cardiac events. The prevalence of cardiac events tended to be greater with a SBP less than 120 mmHg.