The impact of angiotensin-converting enzyme (ACE) gene polymorphism on neurohormonal dose response to ACE inhibitor therapy is unclear.

ACE Insertion (I) or Deletion (D) genotype was determined in 74 patients with chronic heart failure who were randomly assigned to receive either high-dose or low-dose enalapril over a period of 6 months. Monthly pre-enalapril and post-enalapril neurohormone levels (serum ACE activity (sACE), plasma angiotensin II (A-II), plasma renin activity (PRA), and serum aldosterone (ALDO) were compared between genotype subgroups and between patients who received high- or low-dose enalapril within each genotype subgroup.

At baseline, predose/postdose sACE and postdose PRA were significantly higher in the DD genotype. At 6-month follow-up, postdose sACE was reduced in a dose-dependent fashion in all three genotypes (P < .05). However, predose and postdose ALDO and A-II levels did not differ between each genotype subgroup at baseline or by enalapril dose within each genotype subgroup. ALDO escape and A-II reactivation were not affected by ACE genotype or enalapril dosage.

Predose sACE were consistently higher in the DD genotype when compared with ID or II subgroups. Despite a dose-dependent suppression of sACE, there were no observed statistically significant differences in ALDO and A-II suppression or escape with escalating doses of enalapril within each subgroup.