14-week single blind, double baseline, forced-titration, cross-over comparison of the cardiac benefits of Coreg CR compared to valsartan added to existing ACE inhibition

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).

Inclusion Criteria:

• Subjects with residual (uncontrolled) hypertension on lisinopril monotherapy, defined as 24-hour ambulatory diastolic BP >85 mmHg.

Exclusion Criteria:

A subject meeting any of the following conditions will be excluded from the study:

• History of serious adverse effects with ACE inhibitor, Coreg, or valsartan
• Known or suspected causes of secondary hypertension (e.g., renovascular stenosis, primary hyperaldosteronism)
• Known ischemic heart disease requiring beta-blocker therapy (includes angina, prior transmural myocardial infarction, coronary artery bypass graft surgery or percutaneous transluminal coronary angioplasty or stenting within 6 months prior to study entry).
• Heart failure (NYHA Functional Class II-IV)
• Obstructive valvular heart disease or obstructive hypertrophic cardiomyopathy
• Presence of clinically significant ventricular or supraventricular arrhythmias (e.g. atrial fibrillation/flutter), pre-excitation syndrome, second or third degree AV block, other conduction defects necessitating the implantation of a permanent cardiac pacemaker, or sick sinus syndrome.
• Chronic kidney disease (serum creatinine >2.5 within past 6 months)
• Uncontrolled diabetes mellitus (i.e., a fasting blood glucose >200 mg/dL [>11.1 mmol/L] or hemoglobin A1c > 10%
• History of alcohol or other drug abuse within 6 months prior to enrollment
• Concomitant treatment or probable need for treatment with prohibited medications. NSAIDs, diabetes medications and other chronic meds are permitted if continued throughout study without dosage change.
• Any other medical condition which renders the subject unable to complete the study or which would interfere with optimal participation in the study or produce a significant risk to the subject
• Those with persistent systolic BP elevations above 179 mmHg will be discontinued from the study as will those with any significant adverse effect of medication.
• Positive pregnancy test or failure to practice adequate contraception in women of child-bearing potential
• Bronchospastic asthma requiring chronic steroid or inhaler therapy
• Any women with child-bearing potential

Since all 30 participants will receive both drugs, the effects of the 2 drugs on the experimental endpoints will be compared by paired t-test. The 2 study arms refer to the randomization of sequential drug use (ARB first or beta-blocker first), which is designed to guard against the order (carryover) bias that might occur is the same drug sequence was used for all participants.

9 weeks (duration of the crossover study, including 4 weeks each of valsartan or carvedilol in random order and 1 week of follow-up)

Standard definitions

Short duration of trial may miss long-term effects. Statistical powering for primary outcome may preclude secondary analyses.

Drugs names omitted on patient bottles