729-3 Left Ventricular Hypertrophy in Essential Hypertension Depends on ACE Genotype

Abstract

A deletion/insertion polymorphism in the ACE gene accounts for approximately 50% of the variance in plasma angiotensin converting enzyme (ACE) concentration, and may be linked to tissue ACE activity. The deletion allele (D) occurs with increased frequency in patients with hypertrophic and dilated cardiomyopathy. Left ventricular hypertrophy (LVH) is a recognised complication of essential hypertension, and is associated with increased morbidity and mortality. Angiotensin II, which is produced by ACE, promotes myocyte growth and collagen deposition, and has been causally linked with the development of LVH. To examine the contribution of ACE genotype to the development of left ventricular hypertrophy in patients with essential hypertension. Eighty-five consecutive patients (58 males, [59.5%]; mean age 53.8 years) attending the out-patient hypertension clinic were studied. Blood pressure was measured using a semi-automatic sphygmomanometer. Echocardiography was performed and left ventricular mass (indexed for height and weight) was calculated from M-mode measurements according to the Penn convention. DNA was extracted from peripheral blood leucocytes by a commercially available method, and ACE genotype determined by the polymerase chain reaction using standard primers and conditions. DD (n = 25) ID (n = 41) II (n = 19) LVMI (g/M 2 ) † (27.5) 116.1 (42.9) 116.5 (48.2) 108.0 SBP (mmHg) † 149.2 (22.4) 159.1 (28.6) 156.3 (26.5) Relationship of LVMI to SBP p < 0.001 P = 0.002 P = 0.729 D = ACE gene deletion allele; I = ACE gene insertion allele. † Results expressed as mean ± standard deviation There is a significant correlation between LVM and SBP in patients with the deletion allele, but not in homozygotes for the insertion allele. The deletion homozygotes have a similar left ventricular mass to the heterozygotes, but for a lower mean SBP. These data suggest that systolic blood pressure is a major determinant of left ventricular mass in hypertension, but the relationship is expressed only in the presence of the deletion allele.