ASAIO journal : a peer-reviewed journal of the American Society for Artificial Internal Organs
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Arterial blood pressure and echocardiography may provide useful physiological information regarding cardiac support in patients with continuous-flow left ventricular assist devices (cf-LVADs). We investigated the accuracy and characteristics of noninvasive blood pressure during cf-LVAD support. Noninvasive arterial pressure waveforms were recorded with Nexfin (BMEYE, Amsterdam, The Netherlands). ⋯ The dicrotic notch in the pressure waveform was a better predictor of aortic valve opening (area under the curve [AUC] = 0.87) than pulse pressure (AUC = 0.64) and (dP(art)/dt)max (AUC = 0.61). Patients with partial support rather than full support at 9,000 rpm had a significant change in systolic pressure, pulse pressure, and (dP(art)/dt)max during ramp studies, while echocardiographic measures did not change. Blood pressure measurements by Nexfin were reliable and may thereby act as a compliment to the assessment of the cf-LVAD patient.
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Our goal was to develop a less invasive total cavopulmonary connection (TCPC) sheep model for testing total cavopulmonary assist (CPA) devices. Thirteen sheep underwent a right fourth intercostal lateral thoracotomy. In series I (n = 6), a polytetrafluoroethylene (PTFE) extracardiac conduit (ECC) was connected to inferior vena cava (IVC) and superior vena cava (SVC) by end-to-side anastomosis. ⋯ In each series, one sheep died of bleeding. In five sheep in series I and six sheep in series II, the TCPC model was successfully created with significantly increased central venous pressure and significantly decreased PA pressure/arterial blood pressure. Our acute TCPC sheep model has a less traumatic right thoracotomy with no cardiopulmonary bypass and less blood loss with no blood transfusion, facilitating future long-term CPA device evaluation.
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Although ventricular assist devices (VADs) are lifesaving therapy for patients with severe heart failure, complications such as pump thrombosis can occur. In this report, we present a case of VAD thrombosis following recovery of left ventricular (LV) function. ⋯ The patient underwent successful VAD explant and examination of the pump revealed thrombus on the rotor. We propose that abnormal flow through the VAD seen with recovery of LV function may contribute to VAD thrombosis.
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Left ventricular assist devices (LVADs) are fast becoming standard of care for patients with advanced heart failure. However, despite continuous improvement in VAD technology, there remains a significant early postoperative morbidity and mortality in this extreme patient group. The aim of the current study was to explore the short-term outcomes and predictors for 90 day mortality in the patients after implantation of continuous-flow LVAD. ⋯ All-cause 90 day mortality was 17.1%. Multivariate analysis revealed higher preoperative central venous pressure (odds ratio [OR], 1.18; 95% confidence interval [CI], 1.014-1.378; p = 0.033) and higher age (OR, 1.14; 95% CI, 1.01-1.38; p = 0.045) as the only independent predictors for 90 day mortality. Optimization of preoperative volume status, preload, and right heart function as well as age-based selection of candidates for LVAD support are the critical factors influencing early outcome after continuous-flow LVAD implantation.
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Implantation of ventricular assist devices (VADs) for the treatment of end-stage heart failure (HF) falls decidedly short of clinical demand, which exceeds 100,000 HF patients per year. Ventricular assist device implantation often requires major surgical intervention with associated risk of adverse events and long recovery periods. To address these limitations, HeartWare, Inc. has developed a platform of miniature ventricular devices with progressively reduced surgical invasiveness and innovative patient peripherals. ⋯ Anatomic fit and surgical approach were demonstrated using human cadavers (n = 4). Efficacy was demonstrated in acute (n = 2) and chronic (n = 1) bovine model experiments and assessed by improvements in hemodynamics, biocompatibility, flow dynamics, and histopathology. Potential advantages of the MVAD Pump include flow support in the same direction as the native ventricle, elimination of cardiopulmonary bypass, and minimally invasive implantation.