Objectives: Hypotension is common immediately following cardiopulmonary bypass. Experimentally, MTR-105 (S-ethylisothiuronium diethylphosphate), a fast-acting synthetic nitric oxide synthase inhibitor, rapidly increases blood pressure. The purpose of the current study was to assess the influence of MTR-105 on hemodynamics early after cardiopulmonary bypass in patients undergoing open-heart surgery. Methods:Thirty-six patients with an ejection fraction >50% undergoing open-heart surgery were randomly assigned to either 50 µg kg^–1 min^–1 MTR-105 (M50, n = 12), 10 µg kg^–1 min^–1 MTR-105 (M10, n = 12) or buffered phosphate solution (placebo control, n = 12). Half suffered from atrial fibrillation and 75% had severe tricuspid regurgitation. Patients received the drug for 6 h after cross-clamp removal. Hemodynamic variables were measured before drug administration until 24 h after operation. Adverse events were recorded from study drug initiation through 30 days after the operation. Results:Compared with control, both MTR-105 doses were associated with an immediate increase in systemic blood pressure (16%) and systemic vascular resistance and a decrease in cardiac index. Half-life time of MTR-105 was calculated to be 4.1 ± 0.8 h (M10) and 4.45 ± 0.92 h (M50). Three patients died during hospitalization, unrelated to the study medication. Conclusions:At the doses employed, MTR-105 appears hemodynamically active in increasing both blood pressures.

Background. Heart failure (HF) is a well-defined risk factor for early mortality and morbidity after cardiac surgery.We aimed to analyze the evolution of the clinical phenotype of HF at an early stage after heart surgery.Methods. The study included 126 consecutive patients with established chronic HF who fulfilled the cardiac rehabilitation program after undergoing heart surgery (62.23±8.59 years, 67.5% - men). Subjects were divided into 3 groups according to the clinical phenotype of HF: group 1 - HF with reduced left ventricular (LV) ejection fraction (EF) (HFrEF), group 2 - HF with mildly reduced LV EF (HFmrEF) and group 3 - HF with preserved LV EF (HFpEF). All patients were investigated by electrocardiography, transthoracic echocardiography, 6 minutes walk test and assessment of serum NT-proBNP level. Results. Preoperatively, 23.9% of patients had HFrEF, 24.8% - HFmrEF and 51.3% - HFpEF. Analyzing the evolution of the HF phenotype in the early postoperative period, we found that most patients remained in the same group. However, among patients with preoperative HFmrEF, in 22.2% of patients there was an increase in LV EF over 50% and in 22.2% of patients was determined a reduced LV EF, p<0.001. The most obvious positive dynamic of the HF phenotype was attested in patients with HFrEF, where 37% of them presented a mildly reduced LV EF postoperatively, p <0.001. 78.9% of individuals with HFpEF remained in the same group, but 21% showed a decrease in LV EF, p<0.001. Conclusions. At the early stage after cardiac surgery, the most positive evolution of HF phenotype was noticed in the group of patients with HFrEF. Of the 44.4% of patients with HFmrEF who switched to another HF phenotype, only a half reported an increase in LV EF over 50%. The vast majority of patients with HFpEF had the same HF phenotype postoperatively.