Exploring the effects of ACE inhibitor tissue penetration on vascular inflammation following acute myocardial infarction.

BACKGROUND: Questions remain as to the existence of a class effect amongst angiotensin converting enzyme (ACE) inhibitors, and some literature suggests that pharmacological effects and outcomes may be determined by an ACE inhibitor's propensity to penetrate and inhibit the ACE enzyme at the vascular tissue level. Because vascular inflammation contributes to adverse outcomes following acute myocardial infarction (AMI), and angiotensin II influences inflammation at the vascular level, we hypothesized that high-tissue penetrating ACE inhibitors would provide more favorable effects on C-reactive protein (CRP) after AMI compared to low-tissue penetrating ACE inhibitors. METHODS AND RESULTS: In a randomized open-label trial, patients received the high-tissue penetrating quinapril (n = 15) or low-tissue penetrating enalapril (n = 15) following AMI. C-reactive protein was measured at baseline and periodically over 14 days following drug initiation. All baseline characteristics and blood pressure response to treatment between groups were equivalent. Prior to initiating study medication, CRP concentrations (mg/g) were similar between enalapril and quinapril (0.327 +/- 0.571 versus 0.273 +/- 0.380, respectively, p = 0.77). The percent magnitude of change in CRP concentrations favored quinapril at all time points, starting 12 h after treatment initiation. When characterizing CRP production during treatments, the time courses were significantly different and demonstrated lower CRP concentrations with quinapril (p = 0.0107). CONCLUSIONS: Overall, this investigation into the importance of ACE inhibitor tissue penetration on a common marker of vascular inflammation, suggests a potential vascular anti-inflammatory benefit with a more highly tissue penetrating ACE inhibitor following AMI. Further investigation into the true pharmacological similarities and differences amongst this class of drugs is warranted.