ABSTRACT
This experimental study aimed to evaluate the ex-vivo three-dimensional (3-D) motion of the Inverted Arch Ring (IAR), an innovative new design concept for a flexible incomplete annuloplasty prosthesis with an incorporated stabilizing rigid arch that can be used in correcting mitral valve regurgitation. Twenty explanted porcine hearts were placed in a circulation simulation system. Ultrasonometry transducers implanted in the mitral annulus were used to measure the 3-D valvular motion during a simulated cardiac cycle. Annular distance measurements were recorded and compared in each heart before and after the implantation of the IAR prosthesis at pressures corresponding to mid-systole and mid-diastole. Distances measured in mid-systole and mid-diastole demonstrated no significant differences in annular motion or in valve areas either prior to or after IAR implantation. Therefore, the results of this study confirm the minimal effects exerted by the IAR prosthesis on the mitral valve's 3-D motion during a simulated cardiac cycle.
ABSTRACT
Acute cardiac failure caused by myocardial infarction or inadequate cardioprotection during heart surgery is associated with increased mortality and morbidity. Levosimendan is a new drug used in heart failure though it is limited by the systemic hypotension, which develops with intravenous administration. Intracoronary (IC) administration however should affect systemic circulation less while maintaining the beneficial cardiac effects of the drug. We herewith report the results from the first such clinical series. Levosimendan was administered IC in 33 consecutive patients who developed cardiogenic shock during heart surgery and were unable to wean off cardiopulmonary bypass despite maximal support. Preadministration/postadministration coronary graft flows, hemodynamic parameters, left ventricular function, and metabolic requirements were measured and compared. Levosimendan significantly increased graft flows and improved hemodynamic parameters. Systolic blood pressure (93 ± 26.4 vs. 106 ± 18.2 mm Hg, P < 0.05) and cardiac index (2.0 ± 0.5 vs. 3.1 ± 0.2, P < 0.001) were increased, whereas systemic vascular resistance (1470.7 ± 114 vs. 1195.8 ± 112, P < 0.01) was reduced. Better myocardial perfusion improved metabolic requirements, with myocardial oxygen extraction and glucose uptake increasing by 72% and 74%, respectively, whereas lactate production was reduced by 64%. Echocardiography demonstrated additional ventricular segment recruitment. Therefore, IC Levosimendan administration in acute heart failure is safe and efficacious producing improved cardiac function without significant detrimental hypotension.
