BackgroundLow cardiac output syndrome (LCOS) is a severe condition which can occur after cardiac surgery, especially among patients with pre-existing left ventricular dysfunction. Dobutamine, its first-line treatment, is associated with sinus tachycardia. This study aims to assess the ability of intravenous ivabradine to decrease sinus tachycardia associated with dobutamine infused for LCOS after coronary artery bypass graft (CABG) surgery.MethodsIn a phase 2, multi-center, single-blind, randomized controlled trial, patients with left ventricular ejection fraction below 40% presenting sinus tachycardia of at least 100 beats per minute (bpm) following dobutamine infusion for LCOS after CABG surgery received either intravenous ivabradine or placebo (three ivabradine for one placebo). Treatment lasted until dobutamine weaning or up to 48 h. The primary endpoint was the proportion of patients achieving a heart rate (HR) in the 80- to 90-bpm range. Secondary endpoints were invasive and non-invasive hemodynamic parameters and arrhythmia events.ResultsNineteen patients were included. More patients reached the primary endpoint in the ivabradine than in the placebo group (13 (93%) versus 2 (40%); P = 0.04). Median times to reach target HR were 1.0 h in the ivabradine group and 5.7 h in the placebo group. Ivabradine decreased HR (112 to 86 bpm, P <0.001) while increasing cardiac index (P = 0.02), stroke volume (P <0.001), and systolic blood pressure (P = 0.03). In the placebo group, these parameters remained unchanged from baseline. In the ivabradine group, five patients (36%) developed atrial fibrillation (AF) and one (7%) was discontinued for sustained AF; two (14%) were discontinued for bradycardia.ConclusionIntravenous ivabradine achieved effective and rapid correction of sinus tachycardia in patients who received dobutamine for LCOS after CABG surgery. Simultaneously, stroke volume and systolic blood pressure increased, suggesting a beneficial effect of this treatment on tissue perfusion.Trial registrationEuropean Clinical Trials Database: EudraCT 2009–018175-14. Registered February 2, 2010.Electronic supplementary materialThe online version of this article (10.1186/s13054-018-2124-8) contains supplementary material, which is available to authorized users.
We prospectively evaluated the diagnostic accuracy of a new rapid assay (STic Expert HIT) alone or in combination with a clinical score in 90 HIT-suspected patients. The 4Ts score was calculated, and ELISA and serotonin-release assay (SRA) were performed; the average time taken for test results were 2 and 5 days for ELISA and SRA, respectively. The STic test was performed in our laboratory as an evaluation exercise and the result was available in 1 hour, but results were not communicated to the clinicians so as to not influence management. Diagnostic performance of STic test was assessed, alone and in combination with 4Ts score. HIT was diagnosed in 19 patients. The sensitivity, specificity, and positive and negative predictive values for the STic test alone were 95%, 92%, 75%, and 98%, respectively, with an accuracy of 92%. The likelihood ratio for positive and negative results with the STic test was 11.2 and 0.06. The combination of the 4Ts score and the STic test results had a negative predictive value of 100% and a negative likelihood ratio of 0. The favorable performance of the STic test may allow for the rapid exclusion of HIT in combination with a low to intermediate pretest clinical probability. During the subsequent year, using the STic test in real time to rapidly exclude the diagnosis, we observed a 50% reduction in danaparoid administration in HIT-suspected patients.
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