W. Kao

Role of Maximal Oxygen Consumption in Establishment of Heart Transplant Candidacy for Heart Failure Patients With Intermediate Exercise Tolerance

Maximal exercise oxygen consumption (VO2max) was measured in patients with chronic congestive heart failure undergoing evaluation for heart transplantation. Although VO2max correlated with survival for the group as a whole, it did not demonstrate survival discrimination for patients in the intermediate range (VO2max = 12 to 17 ml/kg/min) and should therefore not be used as a benchmark test for determination of appropriateness for cardiac transplantation in this group of patients.

Failure Of An Implantable Left Ventricular Assist Device: A Distinctive Electrocardiographic Pattern Before Malfunction

Long-term implantable left ventricular assist devices (LVADs) have revolutionized the care of patients with heart failure who are awaiting transplantation. 2 The HeartMate Vented Electric (VE) (Thermo Cardiosystems Inc., Woburn, Mass.) Left Ventricular Assist System (LVAS) consists of an implanted LVAD with a percutaneous drive line that connects the internal pump to the external power supply and controller, as well as providing a vent for the internal chamber to the atmosphere. The system is capable of supplying full circulatory support for the left ventricle and is currently being evaluated both as a bridge to transplantation and as a permanent alternative to transplantation in patients with irreversible heart failure. We report a case of primary pump failure that was heralded by a distinctive pattern on the electrocardiogram (ECG). Although device-related failures with currently available implantable LVADs have been extremely uncommon, we believe the ECG findings described, which occurred before device failure, may serve a predictive function and thereby avoid a catastrophic outcome. Clinical summary. The patient was a 60-year-old man who had an acute anterior wall myocardial infarction approximately 4 months before evaluation at our institution. Despite timely thrombolytic therapy and urgent coronary balloon angioplasty of an occluded left anterior descending coronary artery, the infarction progressed and the patient was left with severe residual left ventricular dysfunction, with an estimated left ventricular ejection fraction of approximately 20% by radionuclide ventriculography. After his referral to our institution, he was rehospitalized on two subsequent occasions for decompensated heart failure, which was responsive only to parenteral inotropic agents and diuretics. Despite aggressive medical support, his hemodynamic status continued to deteriorate and he was listed for heart transplantation. Seven months after the infarction, right heart catheterization revealed the following pressures while the patient was maintained on a continuous milrinone infusion: right atrium 8 mm Hg, pulmonary artery 75/39 mm Hg (mean 55 mm Hg), pulmonary artery wedge 40 mm Hg, cardiac index 1.3 L z min z m, and systemic blood pressure 75/50 mm Hg. The patient was judged to have heart failure refractory to maximal medical therapy and the decision was made to proceed with implantation of an LVAD as a bridge to transplantation. The patient’s blood type was O1 and the preoperative panel reactive antibody level was 68%. The device was implanted in the standard fashion with the LVAD positioned in a preperitoneal subcostal pocket with the inflow catheter placed in the left ventricular apex and the outflow graft anastomosed to the proximal ascending aorta. The combined power and control cable exited percutaneously above the left iliac crest in the left lower quadrant of the abdomen. The postoperative course was unremarkable and the patient quickly resumed his preoperative activity level with physical therapy. Anticoagulation consisted of 325 mg of aspirin per day. LVAD flow rates remained at 5 to 6 L/min off all cardiac medications. Renal and pulmonary function remained normal. On postoperative day 82, the patient reported a vague feeling of generalized uneasiness, and the LVAD flow rates indicated on the external console demonstrated a decrease to approximately 3 L/min. Systemic blood pressure remained within normal ranges. An intravenous bolus of normal saline solution was administered, after which the LVAD flow rates returned to baseline and the patient’s symptoms transiently resolved. A 12-lead ECG was obtained (Fig. 1). Approximately 45 minutes later, the patient became acutely unresponsive with minimal meaFrom the Departments of Cardiovascular-Thoracic Surgery, Cardiology, and Pathology, Rush-Presbyterian-St. Luke’s Medical Center, Chicago, Ill.

MANAGEMENT OF ACUTE HEART FAILURE EXACERBATION

Patients with decompensated heart failure should be managed in an aggressive and proactive manner, using predominantly hemodynamic and end-organ function goals. This management is in contrast to the chronic maintenance therapy of patients with heart failure, where a neuroendocrine approach is indicated. Underlying anatomic targets for intervention should be sought aggressively and addressed. Patients who prove resistant to standard measures should be considered for early referral to heart transplant centers for more definitive measures, including evaluation for heart transplantation and mechanical circulatory support if necessary.

Sudden death in heart failure patients: effects of optimized medical therapy

Although medical therapy, particularly with angiotensin-converting enzyme (ACE) inhibitors, has been demonstrated to prolong life in patients with chronic heart failure, the effect of standard medical therapy on sudden unexpected death in patients with heart failure is less well understood. Recent clinical trials have provided new insights into this growing problem. The impact of modern medical therapy for heart failure, including ACE inhibitors, beta-adrenergic antagonists, digoxin, calcium channel antagonists, and antiarrhythmic interventions will be discussed.

Is outcome after heart transplantation influenced by ethnicity? A comparison of African Americans versus Caucasians.

transplantation increases the risk of postoperative complications. The purpose of our current study was to test this hypothesis by evaluating 50 patients who were transplanted at our facility over the past six years. Seventeen (34%) of these patients had received amiodarone prior to transplantation while the remaining thirtythree (64%)had not. Endpoints of the study included: length of hospital stay, survival to hospital discharge, 30 day mortality, 6 month mortality, 1 year mortality, number of days ventilated, ARDS, hepatic failure, number of days paced, need for permanent pacemaker, refractory hypotension, and bleeding complications. There were no significant differences between the two groups in age, sex, etiology of heart failure, LVEF, preoperative platelet or INR values. Patients in the amiodarone group, however, were more likely to be on an assist device or IABP prior to transplantation compared to the non-amiodarone group (47% vs 12%, p50.005). There were no significant differences between the amiodarone and non-amiodarone groups in length of stay (21 vs 17 days, p50.72), 6 month mortality (29% vs 15%, p50.19), 1 year mortality (27% vs 18%, p50.5), days ventilated (8 vs 6, p50.7), ARDS (6% vs 0, p50.16), hepatic failure (18% vs 9%, p50.4), days paced (2 vs 2, p50.67), need for permanent pacemaker (0 vs 3%, p50.47), or refractory hypotension (18% vs 9%, p50.4). Amiodarone patients were less likely to survive to hospital disharge (71% vs 94%, p50.02) and a trend was seen for 30 day mortality (18% vs 3%, p50.07). They were also more likely to experience a bleeding complication (41% vs 9%, p50.007), even when patients on mechanical assist devices were excluded (33% vs 7%, p50.04). In conclusion, amiodarone patients were not at increased risk of ARDS, bradycardia, hepatic failure, or refractory hypotension. Amiodarone patients did experience more bleeding complications in the postoperative period. This finding has important clinical implications for many cardiac transplantation patients and warrants further investigation.