Michael S. Sweeney

Device-supported myocardial revascularization: Safe help for sick hearts☆

Although advances in both the technology of artificial oxygenation and our understanding of myocardial preservation have made aortocoronary bypass operations safer, clinical settings remain where even these improvements have limited efficacy. We have recently treated 43 severely ill patients with aortocoronary bypass, using a ventricular assist device for intraoperative hemodynamic support and ventricular decompression. For 34 of the patients, preoperative ejection fractions (multigated acquisition) ranged from 0.12 to 0.28 (average, 0.22); 6 patients manifested cardiogenic shock preoperatively, and emergency operations precluded multigated acquisition studies. Twenty-nine patients had preoperative evidence of congestive heart failure, 10 had a prior bypass operation, 9 had major chronic obstructive pulmonary disease, and 2 were Jehovahs Witnesses. The operative technique involved minimal doses of heparin (1 to 1.5 mg/kg), no cardioplegia, and no cardiopulmonary bypass. Revascularization was accomplished on beating, nonworking hearts, with right (40 of 43) and left (43 of 43) ventricles supported by Nimbus Hemopumps (4 of 43) or Bio-Medicus centrifugal ventricular assist devices for an average of 112 minutes. In each case, the patients lungs were used as the oxygenator. An average of 3.7 bypass grafts per patient were constructed. The left internal mammary artery was used in 41 patients, whereas at least one coronary endarterectomy was required in 20. Six patients had concomitant placement of an automatic implantable cardioverter defibrillator. Two patients (4.6%) died: 1 (with preoperative cardiogenic shock) of low cardiac output on postoperative day 1, and 1 of a severe neurologic deficit on day 8. Follow-up ranged from 2 to 18 months (average, 8.9 months), with all survivors demonstrating improvement in cardiac function in both the early and late postoperative periods.(ABSTRACT TRUNCATED AT 250 WORDS)

Improved Multiorgan Function After Prolonged Univentricular Support

Eleven cardiac transplant candidates (all male; mean age, 43.3 years) with multiorgan (hepatic, pulmonary, and/or renal) dysfunction were sustained for prolonged periods (> 30 days) with the HeartMate (Thermo Cardiosystems, Inc, Woburn, MA) left ventricular assist device. We evaluated the effect of extended support on end-organ recovery and on the ultimate outcome of cardiac transplantation. In addition to cardiac failure, 9 patients had hepatic dysfunction, 8 had pulmonary dysfunction, and 6 had renal dysfunction (4 of whom required hemodialysis before left ventricular assist device support). Mean duration of support was 115 days (range, 31 to 233 days). All patients underwent successful transplantation; 10 of these patients survived a mean of 24 months. One patient, who had required hemodialysis and ventilatory support during and after support, experienced progressive multiorgan failure and died 7 weeks after transplantation. Two late deaths after transplantation were unrelated to the device. Overall, patients experienced improvement in cardiac functional class status, and most participated in cardiac rehabilitation programs before transplantation. During left ventricular assist device support, hepatic function returned to normal in 8 patients, pulmonary function recovered in 7, and renal function returned to normal in 4. One patient who required hemodialysis underwent renal transplantation after cardiac transplantation and had complete recovery of renal function. In the current era of donor shortages, gravely ill patients can benefit from a strategy of prolonged left ventricular assist device support. This strategy has proved safe, has allowed for reversal of multiorgan dysfunction, and has produced healthier transplant candidates.

Apicoaortic Conduits for Complex Left Ventricular Outflow Obstruction: 10-Year Experience

We interposed valved conduits between the left ventricular apex and aorta in 38 patients over a 10-year period. Indications included tunnel subaortic stenosis, aortic annular hypoplasia, tubular supravalvular aortic hypoplasia, and severe calcification of the ascending aorta. Operative mortality was 11%, but 78% of the survivors were alive at 5 years, and 70% had had no major complication. The results were better in adolescents and adults than in young children. Although complications included calcific degeneration of the valve and disruption of the conduit at the site of insertion into the ventricular apex, we continue to believe in the utility of this procedure in a few patients with complex left ventricular outflow tract obstruction.

Transvalvular left ventricular assistance in cardiogenic shock secondary to acute myocardial infarction: Evidence for recovery from near fatal myocardial stunning

OBJECTIVES The purpose of this study was to test the hypothesis that transvalvular left ventricular assistance would support the circulation in patients with cardiogenic shock secondary to acute myocardial infarction and allow recovery of function in patients with a reversibly damaged (stunned) left ventricle. BACKGROUND Cardiogenic shock occurs in 7.5% of patients presenting with acute myocardial infarction, resulting in survival of only 20%. Despite the use of aggressive interventional therapy in patients with shock secondary to anterior myocardial infarction, survival remains as low as 33%. METHODS We studied 11 patients with acute myocardial infarction and cardiogenic shock, as defined by a cardiac index < 2 liters/min per m2, pulmonary capillary wedge pressure > 18 mm Hg and systolic blood pressure < 90 mm Hg during positive inotropic therapy. Patients were 57 +/- 13 years old (mean +/- SD) and had a mean left ventricular ejection fraction of 25 +/- 11%, mean arterial pressure of 69 +/- 13 mm Hg and mean cardiac index of 1.6 +/- 0.4 liters/min per m2 on admission to the study. RESULTS During the 1st 24 h of left ventricular assistance, pulmonary capillary wedge pressure decreased from 26 +/- 4 to 16 +/- 4 mm Hg (p = 0.01), cardiac index increased from 1.6 +/- 0.4 to 2.4 +/- 0.4 liters/min per m2, and the dopamine hydrochloride dose decreased from 51 +/- 92 to 18 +/- 12 micrograms/kg body weight per min. In survivors, cardiac index improved to 3.2 +/- 0.5 liters/min per m2 (p = 0.01), and left ventricular ejection fraction improved to 34 +/- 5% (p < 0.05). The overall survival in the study group was 4 (36%) of 11 patients (95% confidence interval [CI] 8% to 65%), and 4 (66%) of 6 patients (95% CI 29% to 100%) with a Q wave anterior myocardial infarction survived. CONCLUSIONS Transvalvular left ventricular support during cardiogenic shock complicating acute myocardial infarction is feasible and results in significant hemodynamic and functional improvement.

Blunt trauma to the heart: The pathophysiology of injury

Blunt injuries to the heart are common and potentially lethal. These injuries often go undetected while more obvious problems are treated. A cardiac injury should be suspected in any patient who sustains severe chest trauma. The spectrum of cardiac trauma ranges from injuries with no actual cellular damage (myocardial concussion) to cardiac chamber rupture. The pathophysiology, diagnosis, and treatment of these injuries are discussed.

The Treatment of Advanced Cardiac Allograft Rejection

Severe cardiac allograft rejection remains a serious problem despite the advances of cyclosporine-based immunosuppression. This study analyzes our experience with 202 recipients of cardiac allografts who were treated primarily with cyclosporine and prednisone. Failure of such therapy in 86 patients (43%) resulted in 105 episodes of advanced cardiac allograft rejection as diagnosed by endomyocardial biopsy. Of 101 rejection episodes that were initially treated with intravenous pulse therapy, 48 (48%) were successfully resolved, yet 60% of these successes were associated with major infections. Patients in whom steroid therapy failed or was contra-indicated received intravenous antithymocyte globulin (ATG) or intravenous monoclonal antibody (OKT3). ATG and OKT3 successfully reversed severe rejection in 26 (81%) of 32 and in 13 (93%) of 14 episodes, respectively. Infectious complication rates were 54% and 21%, respectively. Because the majority (87%) of these rejection episodes occurred within the first 30 days after treatment, many of them may have resulted from inadequate immunosuppressive induction therapy. Based on our results, we believe that advanced cardiac allograft rejection may be managed best by individualizing immunosuppressive therapy, thus enhancing prevention, and by adding OKT3 to the regimen when rejection occurs.

Kearns-Sayre syndrome and cardiac anesthesia

T HE KEARNS-SAYRE Syndrome (KSS) is a rare form of mitochondrial myopathy (MM) where ophthalmoplegia is associated with a variety of cardiac conduction and neural and retinal disorders. ~ There are few case reports of anesthesia for patients with KSS. 2-5 Discussed as a case of a patient with KSS who presented for cardiac surgery. The implications for anesthesia include atrioventricular node and infranodal conduction abnormalities, 6 hypoventilation secondary to ventdatory drive depression, 7 potential myopathic or neuropathic changes, 8 possible mahgnant hyperthermia susceptibility, 9 and undue sensitwity to anesthetic induction agents. 2,3

Infections in heart transplantation. III.

Abstract Cardiac allograft recipients, like all transplant patients, are predisposed to infections. Moreover, heart transplant recipients are especially jeopardized by the lack of a fail-safe support system should their grafts be rejected. The subsequent tendency to strongly immunosuppress these recipients results in perhaps a higher overall incidence of postoperative infections and certainly an increase in the number of severe and unusual infections. Management of these patients is complex. It is important to exclude rejection as cause of fever and then evaluate the infectious causes of the febrile episode. In our practice, this evaluation begins by determining the number of days since transplantation, because certain infectious agents and sites characterize each of the three periods of the post-operative course. This approach allows for a rapid and correct diagnosis and augments the creation of a cost-effective and successful therapeutic plan.

Surgical Treatment of Complex Left Ventricular Outflow Obstruction

A few patients with aortic stenosis cannot be managed successfully by conventional techniques. Included in this group are those with fibrous tunnel obstruction of the left ventricular outflow tract, hypoplasia of the aortic annulus, and tubular hypoplasia of the ascending aorta. Patients with recurrent aortic valvar stenosis, after prior attempts at aortic root repair or valvotomy, may also be considered for radical outflow tract reconstruction, especially if infection has contributed to the failure of the previous procedure. Angina pectoris, syncope, easy fatigability, and dyspnea on exertion are all said to be common symptoms; yet many patients are asymptomatic. Whether symptoms are impressive or not, left heart failure and sudden death may occur unless appropriate relief of the obstruction is achieved.