Aggressive Blood Pressure Lowering Is Dangerous: The J-Curve

Controversies in Hypertension 29H istorically, the possibility that reducing blood pressure (Bp) might have harmful effects has gone through 3 temporal steps. in the first half of the last century, it was a widespread belief that an elevated Bp provided the necessary hydraulic gradient to preserve organ perfusion in the face of an increase in systemic vascular resistance, the implication being that hypertension was a compensatory mechanism and no Bp-lowering intervention was justified. 13]456 the possibility that antihypertensive treatment might produce harm rather than benefit resurfaced in the late 70s and 80s, 7,8 however, due in particular to a report that in patients with a high cardiovascular risk the incidence of myocardial infarction was diminished by reducing diastolic Bp to 85 to 90 mm Hg but increased when a more pronounced reduction occurred. 8Despite its important limitations (small number of patients, few cardiac events, and retrospective nature of the observations), the report was widely referred to and revived the popularity that has since characterized the J-curve phenomenon, that is, the possible J-shaped rather than linear relationship of Bp reductions by treatment with incident cardiovascular events.the present article will argue in favor of this hypothesis.it will be acknowledged that at present this is not supported by undisputable evidence such as that provided by randomized trials.it will be emphasized, however, that the J-curve hypothesis is supported by common sense, physiological data, and results from large-scale observational studies, often derived from antihypertensive treatment trials on individuals at high or very high cardiovascular risk.this makes it not just a remote but a real possibility, which deserves to be addressed by future studies. 9its important implications for clinical practice should make investigation on the J-curve phenomenon a priority for cardiovascular medicine.