Diastolic blood pressure as a major determinant of tissue perfusion: potential clinical consequences.

Blood pressure measuring represents a routine investigation in general medicine. In the last decades large studies have determined average blood pressure values all around the world. Large clinical trials have shown that blood pressure reduction irrespective of the used type of therapeutic intervention reduces mortality. Based on the outcomes of these trials current guidelines for hypertension encourage more "aggressive" hypertension treatment compared to recommendations from the past. In clinical practice blood pressure is sometimes reduced even below normotensive values (at least in comparison with pre-treatment levels). However there is evidence that achieving too low levels of diastolic blood pressure during antihypertensive treatment has undesirable effects. Especially in the elderly a diastolic blood pressure reduction below 70 mm Hg should be avoided, because it is associated with increased mortality. A possible explanation of this phenomenon could be that antihypertensive treatment disequilibriates the balance between sufficient perfusion pressure and arteriolar vasodilation, both of which are required for adequate tissue perfusion. Impaired microcirculation, especially in the coronary bed may account for the increased mortality in hypertensive patients with low diastolic blood pressure levels. Thus we support the idea of cautious blood pressure reduction in the elderly. Furthermore, we suggest, that monitoring the level of tissue perfusion in treated hypertensive patients might help to provide individually tailored therapy (Fig. 1, Ref. 9). Full Text (Free, PDF) www.bmj.sk.