[When lowering blood pressure is risky. Cerebral infarct--the paradox of prevention and acute therapy].

The value of a sustained lowering of elevated blood pressure below 140/80 mmHg for primary and secondary prevention of stroke has been demonstrated in controlled studies. In contrast, active lowering of blood pressure in the acute phase of a cerebral infarction is associated with the risk of causing further damage to the brain by reducing perfusion in the region of disordered vascular autoregulation surrounding the ischemic area ("penumbra"). The recommendations of a European Consensus Conference therefore apply, that in the first three days following an acute stroke the blood pressure should be cautiously lowered only when a systolic pressure of 220 mmHg or a diastolic pressure of 120 mmHg is exceeded.