Glomerular hyperfiltration indicates early target organ damage in essential hypertension

One consequence of hypertension (high blood pressure) can be kidney damage, and identification of kidney disease (nephropathy) in its earliest stages is highly desirable. The glomerular filtration rate, the rate at which fluid is filtered by the glomeruli (small structures in the kidney through which fluid passes on its way to becoming urine), may be such an indicator. Increases in the rate (hyperfiltration) are known to precede the development of some kidney diseases. To evaluate whether glomerular filtration rate could be a good predictor of nephropathy, 111 patients with mild to moderate hypertension (diastolic blood pressure consistently higher than 90 mm Hg after resting) were studied. Patients underwent echocardiography (ultrasound examination of the heart) to measure the chambers of their hearts; certain findings are known to be correlated with the risk of vascular disease in hypertensive patients. In 52 patients, invasive studies were performed to evaluate kidney function. Results showed a significant correlation between glomerular filtration rate and the mass and cross-sectional area of the left ventricle (the chamber of the heart that pumps blood to the body). Patients with left ventricular hypertrophy (enlargement) had higher glomerular filtration rates than patients who did not have ventricular hypertrophy. The patients had normal kidney function. Whether glomerular hyperfiltration is an early stage of nephropathy remains to be determined; however, it appears to be related to at least one other variable (left ventricular hypertrophy) that is associated with structural change in hypertensive patients. (Consumer Summary produced by Reliance Medical Information, Inc.)