Use of ranolazine in patients with incomplete revascularization after percutaneous coronary intervention: design and rationale of the Ranolazine for Incomplete Vessel Revascularization Post-Percutaneous Coronary Intervention (RIVER-PCI) trial.

BACKGROUND: Incomplete revascularization (ICR) after percutaneous coronary intervention (PCI) is common and is associated with increased rates of rehospitalization, revascularization, and mortality. Adjunctive pharmacotherapy with ranolazine, an inhibitor of the late sodium current with anti-ischemic properties, may be effective in reducing recurrent events after PCI in patients with ICR. TRIAL DESIGN: RIVER-PCI is a phase 3, randomized, double-blind, placebo-controlled, international event-driven clinical trial evaluating the efficacy of ranolazine in patients with a history of chronic angina and ICR after PCI. Approximately 2,600 participants with ICR post-PCI will be randomized in a 1:1 ratio to ranolazine or matched placebo within 14 days of an index PCI. The primary end point of the trial is time to the first occurrence of ischemia-driven revascularization or ischemia-driven hospitalization without revascularization. Participants will be followed up for a minimum of 1 year and until at least 720 confirmed primary end point events have occurred. Secondary end points include sudden cardiac death, cardiovascular death, myocardial infarction, and measures of quality of life and cost-effectiveness. The evaluation of long-term safety will include all-cause mortality, stroke, transient ischemic attack, and hospitalization for heart failure. Enrollment commenced in November 2011 and was completed in summer 2013. CONCLUSIONS: RIVER-PCI is a novel, large-scale, international, randomized, double-blind, placebo-controlled clinical trial evaluating the role of ranolazine in the long-term medical management of patients with ICR post-PCI.

Effect of ketoconazole on the pharmacokinetic profile of ambrisentan.

Ambrisentan is an endothelin type A (ET(A))-selective receptor antagonist that is metabolized primarily by glucuronidation but also undergoes oxidative metabolism by CYP3A4. The potential for ketoconazole, the archetypal strong inhibitor of CYP3A4, to alter the pharmacokinetic profile of ambrisentan and its oxidative metabolite, 4-hydroxymethyl ambrisentan, was assessed in an open-label, nonrandomized, 2-period, single-sequence study in 16 healthy men. Participants received a single dose of ambrisentan 10 mg alone and after 4 days of ketoconazole 400 mg administered once daily. In the presence of multiple doses of ketoconazole, single-dose ambrisentan AUC(0-infinity) estimate was increased by 35.3%, whereas C(max) was increased by 20.0%. For the 4-hydroxymethyl ambrisentan metabolite, AUC(0-infinity) estimate was decreased by 4.0%, whereas C(max) was decreased by 16.5%. Concomitant administration of ambrisentan and ketoconazole was well tolerated. In summary, ketoconazole had no clinically significant effect on the pharmacokinetics or safety profile of ambrisentan; therefore, no changes in ambrisentan dose should be necessary when the drug is administered concomitantly with known CYP3A4 inhibitors.

Valvular myofibroblast activation by transforming growth factor-beta: implications for pathological extracellular matrix remodeling in heart valve disease.

The pathogenesis of cardiac valve disease correlates with the emergence of muscle-like fibroblasts (myofibroblasts). These cells display prominent stress fibers containing alpha-smooth muscle actin (alpha-SMA) and are believed to differentiate from valvular interstitial cells (VICs). However, the biological factors that initiate myofibroblast differentiation and activation in valves remain unidentified. We show that transforming growth factor-beta1 (TGF-beta1) mediates differentiation of VICs into active myofibroblasts in vitro in a dose-dependent manner, as determined by a significant increase in alpha-SMA and the dramatic augmentation of stress fiber formation and alignment. Additionally, TGF-beta1 and increased mechanical stress function synergistically to enhance contractility. In turn, contractile valve myofibroblasts exert tension on the extracellular matrix, resulting in a dramatic realignment of extracellular fibronectin fibrils. TGF-beta1 also inhibits valve myofibroblast proliferation without enhancing apoptosis. Our results are consistent with activation of a highly contractile myofibroblast phenotype by TGF-beta1 and are the first to connect valve myofibroblast contractility with pathological valve matrix remodeling. We suggest that the activation of contractile myofibroblasts by TGF-beta1 may be a significant first step in promoting alterations to the valve matrix architecture that are evident in valvular heart disease.