Morphometric investigation of intramyocardial arterioles in right septal endomyocardial biopsy of patients with arterial hypertension and left ventricular hypertrophy.

A reduced maximal coronary vasodilatator capacity is reported in patients with hypertensive heart disease, suggesting structural abnormalities of intramyocardial arterioles. Right septal endomyocardial catheter biopsies (EMCB) of 30 patients with arterial hypertension and of 10 heart donors were investigated morphometrically. In hypertension, the mean external diameter (21.9 +/- 3.0 vs. 17.4 +/- 2.9 microns, p less than or equal to 0.01) of arterioles and the mean arterial wall area (284 +/- 80 vs. 167 +/- 69 microns2, p less than or equal to 0.05) were increased as compared with heart donors. Perivascular fibrosis was markedly increased (260 +/- 183 vs. 41 +/- 30 microns2, p less than or equal to 0.05) as well as volume density of fibrosis (3.0 +/- 1.7 vs. 0.9 +/- 0.8 Vv%, p less than or equal to 0.01) in hypertensive heart disease. There was no significant correlation between echocardiographically determined left ventricular mass index (115 +/- 25 g/m2 for men and 104 +/- 12 g/m2 for women) and mean arteriolar wall area (r = +0.17) or volume density of fibrosis (r = +0.2) in hypertensive heart disease. Our investigations show that in patients with arterial hypertension there is a thickening of intramyocardial arteriolar walls and an increase in fibrosis. Intramyocardial vascular alterations seem to manifest in hypertension independent from left ventricular hypertrophy.