Circadian Blood Pressure Changes and Cardiac Abnormalities in IgA Nephropathy

Abstract

The absence of diurnal blood pressure rhythm is characteristic of patients with chronic glomerulonephritis already before they develop hypertension. The prognostic importance and possible target organ-damaging effect of the absence are unknown. Simultaneously, 24-hour ambulatory blood pressure monitoring and echocardiographic investigations were done in 12 normotensive and 38 hypertensive IgA nephropathy patients. The hypertensive patients were treated with either angiotensin-converting enzyme inhibitor (ACEI) alone or in combination with a non-dihydropyridine calcium channel blocker. The absence of a night-time blood pressure reduction was frequent in both groups (5/12 vs. 20/38). In the hypertensive patients, blood pressure and left ventricular mass index were higher (124.6 ± 23.3/81.2 ± 15.3 vs. 106.6 ± 33.4/67.4 ± 21.8 mm Hg, p < 0.001, and 124.1 ± 46.2 vs. 89.2 ± 45.6 g/m², p < 0.01). Diastolic left ventricular function was better in normotensive patients, in whom E wave/A wave ratio (E/A) and decelaration time values correlated closely with the diastolic diurnal index (E/A, r = 0.86, p < 0.01; DT, r = –0.70, p < 0.01). In the hypertensive patients, both the left ventricular wall thickness and diastolic function were significantly related to nighttime blood pressure and diurnal index values, but there was no relationship with daytime blood pressure. In conclusion, in IgA nephropathy patients there are mild cardiac abnormalities before they develop hypertension, the abnormalities bearing the closest correlation with the decrease in diurnal blood pressure rhythm. These data suggest the inefficacy of ACEI and calcium channel blockers in treating nighttime hypertension and in reestablishing diurnal rhythm. These phenomena are of great importance in the development of left ventricular hypertrophy and diastolic malfunction.