Risk from low blood pressure in frail older adults: diastolic pressure and pulse pressure are important.

Blood pressure measurement with a cuff in patients with stiff arteries can be misleading, with false elevation of the diastolic pressure. Coronary flow, and most of the cerebral blood flow occur during diastole. There is a marked diastolic J curve in patients with diastolic pressure <60 mmHg and pulse pressure >60 mmHg. Aiming for a systolic target of 120 mmHg is not safe in some frail older patients.