Blood pressure load and target organ effects in patients with essential hypertension.

The ambulatory blood pressure load has been defined as the elevated systolic and/or diastolic pressures over a 24-h period. This parameter, in a sense, represents the chronic pressure overload that induces myocardial and vascular damage associated with the hypertensive disease process. In recent years, blood pressure load has been arbitrarily defined as the percentage of blood pressures greater than 140/90 mmHg while awake and greater than 120/80 mmHg during sleeping hours or the integrated area under the blood pressure curve above the same values. Recent data presented here demonstrate that blood pressure load, expressed as a percentage value in mild hypertensives or as an integrated area under the curve in more moderate and severe hypertensives, is a better determinant of cardiac or vascular abnormalities than either casual or mean ambulatory blood pressure.