The concept of the J-curve effect has been around for a long time and is a subject of contention among various investigators. The J-curve effect describes an inverse relation between low blood pressure (BP) and cardiovascular complications. Because the coronary arteries are perfused during diastole, this effect is seen mostly with low diastolic BP in the range of 70 to 80 mm Hg, depending on preexisting coronary artery disease, hypertension, or left ventricular hypertrophy. Although national and international guidelines recommend aggressive BP control to <140/90 mm Hg for uncomplicated hypertension or <130/80 mm Hg for hypertension associated with coronary artery disease, diabetes, or chronic kidney disease, recent large clinical outcomes trials have observed a J-curve effect between diastolic BP <80 mm Hg as well as systolic BP <130 mm Hg and have cast some doubt regarding the aggressive BP treatment, or "the lower the better," concept. Other recent studies have shown no benefit with respect to cardiovascular complications between aggressive and less aggressive BP control. In contrast to cardiovascular complications, no J-curve effect has been noted for strokes. A Medline search of English-language reports published from 1992 to 2010 regarding this topic was conducted, and 11 reports were selected and are discussed in this brief review, together with collateral published research. In conclusion, most of the reviewed publications suggest a J-curve effect with low diastolic and systolic BP for cardiovascular disease complications but not stroke complications.
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