Even after undergoing treatment, hypertensive patients remain at increased risk for morbidity and mortality from cardiovascular disease. The principal reason for this is believed to be inadequate therapy, since at least two thirds of patients with treated hypertension have blood pressure levels persistently higher than 140/90 mm Hg. Many authors have expressed concern that lowering blood pressure excessively may be hazardous, and the optimal target levels for blood pressure reduction have never been established. In addition, the role of aspirin therapy in hypertensive patients has not been defined. The controversy concerning aspirin centers on balancing its benefits in preventing stroke and myocardial infarction against the increased risk of cerebral hemorrhage. The international Hypertension Optimal Treatment trial conducted by Hansson and colleagues assessed the optimal reduction in blood pressure and the role of aspirin in the management of hypertension.
The study involved 18,790 patients in 26 countries. Participants were 50 to 80 years of age (mean age: 61.5 years) and had confirmed hypertension with diastolic pressures between 100 and 115 mm Hg. All patients were treated with felodipine, with the dosage adjusted or additional agents (angiotensin converting enzyme inhibitors or beta blockers) added to achieve target diastolic blood pressures of less than 90 mm Hg (6,264 patients), less than 85 mm Hg (6,264 patients) or less than 80 mm Hg (6,262 patients). All blood pressures were measured using standardized and stringent criteria. The mean follow-up time was 3.8 years. Only 2.6 percent of patients were lost to follow-up and, at the end of the study, 78 percent of patients were still taking the medication.
The major cardiovascular events were lowest at a blood pressure level of 138.5/82.6 mm Hg. For myocardial infarction, no defined minimum blood pressure could be established, but the optimal systolic blood pressure was calculated to be 142.2 mm Hg. For all types of cardiovascular mortality, the risk was lowest at 138.8/86.5 mm Hg. For stroke, the optimal systolic blood pressure was 142.2 mm Hg, and the optimal diastolic blood pressure was below 80 mm Hg.
In addition to blood pressure reduction agents, over 9,000 patients were randomly assigned to receive either placebo or aspirin, 75 mg per day. Aspirin therapy was associated with a 15 percent reduction in major cardiovascular events and, most significantly, a 36 percent reduction in myocardial infarction. No difference was observed in stroke or in fatal bleeding events, but the aspirin group had 129 major events, which was significantly greater than the 70 nonfatal bleeding events in the group receiving placebo.
The authors conclude that lowering blood pressure with medication was highly beneficial to hypertensive patients, with the optimal effect at 140/85 mm Hg or lower. The addition of small dosages of aspirin reduced the risk of myocardial infarction. The benefits were particularly marked in patients with diabetes.