RITZ-5: Randomized intravenous TeZosentan (an endothelin-A/B antagonist) for the treatment of pulmonary edema - A prospective, multicenter, double-blind, placebo-controlled study

Objectives The objective of this study was to evaluate the addition of intravenous (IV) tezosentan to standard therapy for patients with pulmonary edema. Background Tezosentan is an IV nonselective endothelin (ET)-1 antagonist that yields favorable hemodynamic effects in patients with acute congestive heart failure (CHF). Methods Pulmonary edema was defined as acute CHF leading to respiratory failure, as evidenced by an oxygen saturation (SO2)<90% by pulse oxymeter despite oxygen treatment. All patients received oxygen 81/min through a face mask, 3 mg of IV morphine, 80 mg of furosemide, and 1 to 3 mg/h continuous drip isosorbide-dinitrate according to their blood pressure level and were randomized to receive a placebo or tezosentan (50 or 100 mg/h) for up to 24 h. Results Eighty-four patients were randomized. The primary end point, the change in SO2 from baseline to 1 h, was 9.1 +/- 6.3% in the placebo arm versus 7.6 +/- 10% in the tezosentan group (p=NS). The incidence of death, recurrent pulmonary edema, mechanical ventilation, and myocardial infarction during the first 24 h of treatment was 19% in both groups. Reduced baseline SO2, lower echocardiographic ejection fraction, high baseline mean arterial blood pressure (MAP), and inappropriate vasodilation (MAP reduction at 30 min of <5% or >30%) correlated with worse outcomes. A post-hoc analysis revealed that the outcome of patients who received only 50 mg/h tezosentan was better than patients in the placebo group whereas patients receiving 100 mg/h had the worst outcomes. Conclusions In the present study, tezosentan (an ET-1 antagonist) did not affect the outcome of pulmonary edema, possibly because of the high dose used.