Cardioprotective Benefits of Carvedilol-CR or Valsartan Added to Lisinopril

Combination drug therapy is necessary for optimal blood pressure reduction and current guidelines mandate the concomitant use of ACE inhibitors and β-blockers in most patients at significant risk for cardiovascular disease (CVD) events. There is also continuing interest in combining angiotensin receptor blockers (ARBs) with ACE inhibitors in hypertension based on the unsubstantiated belief that "more complete" renin-angiotensin system inhibition is desirable. It is more attractive physiologically to combine a long-acting β-blocker with vasodilatory actions (carvedilol CR) with an ACE inhibitor because this combination addresses more directly the two fundamental hemodynamic changes needed to reduce CVD events: lowering systolic BP (afterload) and lowering heart rate; the product of the two is a reliable surrogate for reduced cardiac work. In fact, clinical trial data suggest that there is no appreciable additional BP lowering when ARBs are added to ACE inhibitors and neither class lowers heart rate. The present proposal is designed to demonstrate the superior "cardioprotection" of carvedilol CR compared to ARB (valsartan) when each is added to background ACE inhibitor therapy. Principal dependent variables include ambulatory cardiac work (24-hour mean ambulatory systolic BP x heart rate) and laboratory stress responses (central systolic time-tension indices derived from arterial tonometry pre- and post-bicycle exercise). Secondary hemodynamic variables will define changes in flow and pressure (e.g. central systolic BP and forward and reflected pressure wave estimations).