Motonobu Nishimura

Importance of luxury flow for critically ill patients receiving a left ventricular assist system

The presence of a significant organ dysfunction does not immediately exclude patients from consideration for treatment with a left ventricular assist system (LVAS). However, in treating morbid circulatory shock patients with multiple organ failure, it is important to know the preoperative and postoperative factor or factors related to the recovery of the damaged organ function. In this study, we retrospectively analyzed patients receiving a LVAS at our institution and tried to determine the important factors related to the survival of patients with multisystem failure. Twenty-seven patients who underwent LVAS placement at Saitama Medical School Hospital between 1993 and 2003 were included in this study. The preoperative risk factors analyzed were renal dysfunction, respiratory dysfunction, hepatic dysfunction, the existence of active infection, and the combination of all four factors. As a postoperative factor, the pump flow index (mean LVAS pump flow during the first 2 weeks after LVAS surgery divided by the body surface area) was analyzed. None of the analyzed preoperative factors could predict survival after LVAS surgery, but a pump flow index of less than 2.5 l/min/m2 had a significant relationship with death after LVAS surgery. Further analysis revealed that all the patients with a pump flow index of 3.0 l/min/m2 or more could overcome preoperative organ dysfunction. Congestive heart failure patients with multisystem failure need luxury pump flow for successful LVAS surgery; this factor could be especially important in device selection and postoperative management.

Successful bridge to resynchronization therapy with a left ventricular assist system in a patient with idiopathic dilated cardiomyopathy

Implantation of a left ventricular assist system (LVAS) in patients with idiopathic dilated cardiomyopathy (DCM) may improve cardiac function and allow explantation of the device. Generally, an ejection fraction of more than 40% is considered necessary for successful weaning from an LVAS, but less than 10% of DCM patients with an LVAS can achieve such a significant recovery of cardiac function. Cardiac resynchronization therapy, or atrial-synchronized biventricular pacing, has been found to treat congestive heart failure and ventricular dyssynchrony effectively. Here we report on a patient with an LVAS, in whom enough functional recovery could be obtained with resynchronization therapy for the device to be explanted successfully. A 32-year-old man was implanted with a Toyobo-NCVC paracorporeal LVAS to treat his intractable heart failure caused by idiopathic dilated cardiomyopathy. While on the LVAS for 8 months, his cardiac function recovered to some extent. The ejection fraction of his left ventricle (LVEF) improved from 9% to 41%. He chose explantation of the device rather than heart transplantation. Because he occasionally showed a wide QRS pattern on his ECG, epicardial biventricular pacing leads as well as a biventricular pacemaker were implanted on LVAS explantation surgery. An echocardiogram 2 weeks after explantation showed a marked difference in his LVEF by switching his biventricular pacing on and off (40% with biventricular pacing on and 29% with it off). Biventricular pacing may help recovery of cardiac function in selected LVAS patients and contribute to the increase in bridge to recovery cases.

Japanese multicenter clinical evaluation of the HeartMate vented electric left ventricular assist system

Implantable left ventricular assist device systems (LVAS) are increasingly being used to bridge patients to heart transplantation because of the limited number of available donor hearts. This prospective, multicenter trial was designed to evaluate the usefulness of the HeartMate vented electric (VE) LVAS as a bridge to transplantation in Japan. Between November 2001 and June 2003, six patients with end-stage heart failure [New York Heart Association (NYHA) class IV] were supported with the LVAS and five of the six were able to implement the evaluation (one dropped out). The five were men with an average age of 38.6 years and were supported for 2390 cumulative days (6.6 years). Average preimplant cardiac index improved from 1.93 l/min/m2 to a 3.79 l/min/m2 VAD flow index at the end of the clinical trial. All five patients improved to NYHA class I or II, survived more than 1 year, and one patient was discharged from the hospital. Mean LVAS support duration was 478 days (range 390–575 days) and four patients remain supported. One patient died from cardiac failure and sepsis. Device-related complications included: infections (four patients), thromboembolism (one patient), hemolysis (two patients), and repeat operation for bleeding (two patients). There was one case of inflow valve incompetence and two pump motor malfunctions. We conclude that the LVAS can effectively support patients as they await cardiac transplantation and offers improvement to the patient’s quality of life.

Fifteen-month circulatory support for sustained ventricular fibrillation by left ventricular assist device

1. Pennington DG, McBride LR, Peigh PS, Miller LW, Swartz MT. Eight years’ experience with bridging to cardiac transplantation. J Thorac Cardiovasc Surg. 1994;107:472-81. 2. Peterze B, Lonn U, Jansson K, Rutberg H, Casimir-Ahn H, Nylander E. Long-term follow-up of patients treated with an implantable left ventricular assist device as an extended bridge to heart transplantation. J Heart Lung Transplant. 2002;21:604-7. 3. Bank AJ, Mir SH, Nguyen DQ, Bolman RM 3rd, Shumway SJ, Miller LW, et al. Effects of left ventricular assist devices on outcomes in patients undergoing heart transplantation. Ann Thorac Surg. 2000;69: 1369-75. 4. Sun BC, Catanese KA, Spanier TB, Flannery MR, Gardocki MT, Marcus LS, et al. 100 long-term implantable left ventricular assist devices: the Columbia Presbyterian interim experience. Ann Thorac Surg. 1999;68:688-94. 5. Massad MG, McCarthy PM, Smedira NG, Cook DJ, Ratliff NB, Goormastic M, et al. Does successful bridging with the implantable left ventricular assist device affect cardiac transplantation outcome? J Thorac Cardiovasc Surg. 1996;112:1275-83.

Lethal thrombus in the carotid artery during operation for acute aortic dissection with cerebral malperfusion.

A drowsy patient with acute type A aortic dissection and cerebral malperfusion required emergency operation. Because the right carotid artery was totally obstructed, cerebral perfusion was first restored by cannulating it and the left femoral artery before midline sternotomy. However, a long fresh thrombus was found flowing backward from the obstructed carotid artery. This thrombus was removed, and both arteries were connected through a Y-shaped extracorporeal circulation circuit to reperfuse the brain. During the subsequent aortic procedure, both arteries were used for arterial inflow. Such thrombi can cause grave postoperative neurologic dysfunction. Carotid artery cannulation is mandatory in such cases.