Controversies in hypertension: is lower blood pressure always better?

Abstract

Cardiovascular disease risk is continuously related to BP over the range of about 115/75 to 185/115 mmHg, yet all clinical guidelines use arbitrary cutoffs to determine acceptable antihypertensive therapy. There is substantial conflict in the results of clinical trials with respect to how low the most appropriate BP threshold should be to reduce CVD and renal risk. This divergence should not be surprising given the intrinsic differences in circulatory anatomy and physiology among the heart, brain, vessels, and kidney. In the real world, however, discreet BP targets or even ranges may be a tolerable practical necessity as long as it is recognized that any arbitrary threshold in a continuous relationship can serve as both a stimulus and a barrier to effective treatment. Overall, it may be necessary to assess risk differentially by organ or disease process; lower systolic pressure is most beneficial in preventing recurrent stroke and heart failure episodes, benefits on kidney function and ischemic heart disease are less demonstrable for a variety of scientific and experimental design reasons. It may also be a good time for practice guideline writers and individual physicians to re-evaluate the benefits of lower BP targets.