George J. Magovern

Extracorporeal membrane oxygenation for adult cardiac support: the allegheny experience

BACKGROUND A mix of cardiac assist options is necessary to meet the diverse indications for cardiac support in a comprehensive heart failure program. At our institution, an adult extracorporeal membrane oxygenation (ECMO) system comprising a centrifugal pump and hollow fiber membrane oxygenator is used for short-term and temporary cardiac assist. METHODS Between December 1991 and August 1997, 82 adult cardiac patients were supported on ECMO. Indications for cardiac assist included postcardiotomy cardiogenic shock (PCCS, 55 patients), high-risk cardiology intervention (27 patients), perioperative cardiac graft failure (4 patients), and emergency cardiac resuscitation (6 patients). Data for analysis were collected by prospective completion of standardized ECMO report forms and retrospective review of hospital charts. RESULTS The ECMO system was inexpensive to operate, uncomplicated to implant, and adaptable for diverse indications. Survival in PCCS was 20 of 55 patients (36%), with an increased survival rate of 56% (18 of 32 patients) in patients with PCCS after isolated coronary bypass. Catheter-based revascularizations were successfully performed in 26 of 27 (96%) high-acuity patients temporarily supported by ECMO, and 23 of 27 patients (85%) survived to discharge. Survival in the cardiac graft failure group was 2 of 4 (50%). No patient supported on ECMO for cardiac resuscitation survived. CONCLUSIONS ECMO provides good cardiopulmonary and end-organ support; survival rates are similar to or higher than those seen with centrifugal pump support in comparable patient populations.

Clinical cardiomyoplasty: review of the ten-year United States experience.

BACKGROUND Clinical trials of dynamic cardiomyoplasty were pioneered at Allegheny General Hospital beginning in September 1985. Data from 9 years of experience with the procedure at this institution and more recent data from newer cardiomyoplasty centers have been analyzed for outcome analysis and future trends. METHODS Each patient underwent a cardiomyoplasty procedure using the left or right latissimus dorsi muscle. Thirty-four patients were studied at Allegheny: 5 patients implanted with dual chamber pacemakers as single stimulus myostimulators, 11 patients composing the phase I Food and Drug Administration trial of the Medtronic burst myostimulator, and 18 patients entered in the phase II Medtronic trial. Patients from seven additional centers entered the phase II trial in 1991. Fifty-seven patients completed follow-up studies to 1 year after operation in this trial. RESULTS Operative mortality was 5/57 (11%) in the American phase II group and 5/34 (15%) in the Allegheny group (1/18, 6% for Allegheny phase II). Nineteen patients (19/57, 33%) from the combined phase II population died in the first year, and 10/34 (29%) in the Allegheny study. The predominant cause of postdischarge death was arrhythmia (12/19, 63% American; 7/10, 70% Allegheny). In all groups significant improvement was seen in quality of life and functional class. Phase II patients demonstrated significant increases in ejection fraction and stroke work. CONCLUSIONS Failure to sustain improvement and arrhythmia-related death are complex challenges for this procedure; however, realistic solutions have been proposed and are under investigation.

Use of the BioMedicus Centrifugal Pump in Traumatic Tears of the Thoracic Aorta

Traumatic blunt thoracic aortic injury is a clinical entity of increasing incidence. After the diagnosis of traumatic tear of the aorta is made, there is some controversy over whether the aorta should be repaired using cardiopulmonary bypass, a heparinized shunt, or cross-clamping and graft interposition without a shunt or bypass. At Allegheny General Hospital, 19 patients were treated for traumatic tears of the thoracic aorta between July 1, 1977, and June 30, 1983. They can be divided into two groups: Group 1 (July 1, 1977, through October 31, 1981), in which no shunt or bypass or only a heparinized shunt was used, and Group 2 (November 1, 1981, through June 30, 1983), in which left atrium-femoral artery bypass was performed using a BioMedicus heparinless pump and tubing. Among the 10 patients in Group 1, 4 died and 2 had paraplegia postoperatively. Among the 9 patients in Group 2, 1 died and none experienced paraplegia following operation. We believe that the BioMedicus centrifugal pump is a simple, safe means of perfusing the lower body, kidneys, and spinal column without necessitating heparinization in a patient with multiple injuries or the placement of a cumbersome heparinized shunt. Because of the simplicity and the reliability demonstrated, this pump should be considered for use in all patients with traumatic tears of the thoracic aorta.

Paced skeletal muscle for dynamic cardiomyoplasty

Four patients, each with a history of myocardial infarction and diffuse coronary artery disease, underwent application of left latissimus dorsi (LD) muscle with intact neurovascular bundle to the anterolateral wall of the left ventricle. The muscle was conditioned over a six-week period subsequent to operation in 3 patients and was conditioned preoperatively with a burst stimulus in the fourth. Biopsy specimens confirm the experimental data that human skeletal muscle can be electrically conditioned over a six- to ten-week period to contain mainly fatigue-resistant type I fibers. All patients survived the procedure, and 3 showed improvement secondary to aneurysmectomy. In Patient 1, a modified resection was performed, and at 28 months after operation, at the 75-W level of exercise, the ejection fraction was 54% paced versus 45% nonpaced. In Patient 2, at 12 months, the ejection fraction at rest was 44% paced versus 30% nonpaced. Doppler echo studies confirmed the presence of the flap and its function in the paced and nonpaced mode. The third patient died of a sudden ventricular arrhythmia 2 months following operation. An infected, nonfunctioning, degenerated flap was found at autopsy. Patient 4 did not have an aneurysm. She received a bypass graft to the right coronary artery and underwent cardiomyopexy in an attempt to relieve medically refractory incapacitating chronic congestive heart failure. Ten months postoperatively, ejection fraction at rest was 33% paced versus 25% nonpaced. Constrictive myopathy has not been encountered in any of these patients.

Mechanical Support of the Failing Heart

Mechanical ventricular assist with a centrifugal pump with or without anticoagulation for an extended period has been used in 41 patients with postcardiotomy ventricular failure. Left ventricular, right ventricular, and biventricular assist were required. The efficacy and safety of mechanical ventricular assist have been documented. Marked improvement in survival has been observed in the more recent part of this series, and is attributed to earlier employment of the assist device, maintenance of better flow rates near physiological levels, and use of biventricular assist to provide effective circulatory support. Mechanical ventricular assist is easy to use, and the conversion from ordinary cardiopulmonary bypass is also easy. Therefore, mechanical assist provides a very effective means of temporary circulatory assist.

Partial versus full sternotomy for aortic valve replacement.

BACKGROUND Recent trends suggest that smaller incisions reduce postoperative morbidity. This study tests the hypothesis that a partial upper sternotomy improves patient outcome for aortic valve replacement. METHODS A group of 50 patients who underwent aortic valve surgery through a partial upper sternotomy (group I) were compared to 50 patients who underwent aortic valve replacement through a median sternotomy during the same time period (group II). The mean age (60+/-2 versus 63+/-2 years; mean +/- SEM) and preoperative ejection fractions (53+/-2 versus 54+/-2) were similar. Operations were performed with central cannulation, and antegrade/retrograde blood cardioplegia. RESULTS There was one death in each group. No differences were found in aortic occlusion time, mediastinal drainage, transfusion incidence, narcotic requirement, length of stay, or cost. The incidence of pleural and pericardial effusions was increased (18.4% versus 3.9%, p < 0.03), and the need for postoperative inotropic support was higher (38.7% versus 19.6%, p < 0.03) in the partial sternotomy group. CONCLUSIONS Aortic valve replacement can be performed through a partial sternotomy with results comparable to full sternotomy. The partial sternotomy offers a cosmetic benefit, but does not significantly reduce postoperative pain, length of stay, or cost.

Paced latissimus dorsi used for dynamic cardiomyoplasty of left ventricular aneurysms.

Two patients are described, each with a large left ventricular aneurysm and severe coronary artery disease, and each with an ejection fraction lower than 30% and in congestive heart failure. In both, the left latissimus dorsi (LD) muscle was used in the repair of the ventricular aneurysm because preoperative studies demonstrated that there was concomitant coronary artery disease, and there was a strong suggestion that resection of the entire aneurysm would seriously compromise the residual ventricular capacity. One patient had an 18-year history of coronary occlusion with two infarctions. A large, calcified ventricular aneurysm developed, and despite vigorous medical treatment, intractable congestive heart failure and angina persisted. The diffuse coronary artery disease made this patient a poor candidate for bypass grafting. The other patient sustained an acute myocardial infarction 5 months prior to operation. The left anterior descending coronary artery was totally occluded, and a large apical aneurysm developed along with an akinetic anterior wall and septum. After his heart attack, the patient had progressive dyspnea on exertion. Following operation in both patients, the transpositioned LD, then a component in the repair of the left ventricular wall, was electrically trained to synchronously contract with each systole, driven by a standard dual-chamber cardiac pacemaker. Steady improvement and a return to normal activities were observed in both patients. There was an indication of improved ejection fraction with synchronous contraction of the skeletal muscle.

Percutaneous cardiopulmonary bypass for the treatment of hypothermic circulatory collapse

Environmentally induced hypothermia has a very high mortality. Cardiopulmonary bypass affords the best chance of survival from hypothermia but can be time-consuming to institute. We have utilized percutaneous cardiopulmonary bypass with recently developed bypass catheters to resuscitate a patient with profound hypothermia complicated by circulatory collapse. Percutaneous cardiopulmonary bypass appears to be the treatment of choice for profound hypothermia.

Infectious Complications and Cost-Effectiveness of Open Resuscitation in the Surgical Intensive Care Unit after Cardiac Surgery

From July, 1982, to May, 1984, 2,412 patients underwent cardiac surgery. Open resuscitation through a midline sternotomy was performed in the surgical intensive care unit (SICU) 88 times in 64 patients one minute to 10 days after admission. There were 49 initial survivors; 31 patients had primary closure in the SICU (Group 1), and 18 patients had delayed closure (Group 2). In Group 1 there was 1 death. Wound infection developed in 2 of the 30 survivors--Escherichia coli in 1 and Staphylococcus epidermidis in 1. The latter required subsequent debridement. In Group 2 there were 8 survivors and no wound infections. Fifteen patients could not be resuscitated because of ventricular arrhythmia (13%), asystole (33%), cardiogenic shock (47%), and tamponade (7%). Only 2 of 38 patients, or 5%, experienced wound infections. This study demonstrates that open resuscitation in the SICU is a safe, rapid, and cost-effective procedure that will allow earlier intervention, diagnosis, and treatment. In no instance was death attributed to wound infection, and at our institution, this method resulted in cost savings of more than

Twenty-five-year review of the Magovern-Cromie sutureless aortic valve

1,000 per patient.