Intraoperative Management of an Orthotopic Porcine-to-Human Cardiac Xenotransplant.

We report the intraoperative management of an orthotopic cardiac xenotransplant in a 57-year-old man with nonischemic cardiomyopathy requiring venoarterial extracorporeal membrane oxygenation. Transesophageal echocardiography was used for preharvest assessment. Continuous ex vivo perfusion of the heart was performed. Steps were taken to avoid potential xenozoonosis transmission to other patients and staff. Preclinical experience guided our intraoperative management in controlling hemodynamics and using prophylactic antiarrhythmic medications. Echocardiography aided in the diagnosis of aortic dissection in the patient after transplant. Intraoperative cardiac function was excellent. The patient was weaned from all mechanical support 4 days after transplant.

Reevaluating the Ethical Issues in Porcine-to-Human Heart Xenotransplantation.

A major limiting factor with heart allotransplantation remains the availability of organs from deceased donors. Porcine heart xenotransplantation could serve as an alternative source of organs for patients with terminal heart failure. A first-in-human porcine xenotransplantation that occurred in January 2022 at the University of Maryland Medical Center provided an opportunity to examine several ethical issues to guide selection criteria for future xenotransplantation clinical trials. In this article, the authors, who are clinicians at UMMC, discuss the appropriate balancing of risks and benefits and the significance, if any, of clinical equipoise. The authors also review the alleged role of the psychosocial evaluation in identifying patients at an elevated risk of posttransplant noncompliance, and they consider how the evaluation's implementation might enhance inequities among diverse populations. The authors argue that, based on the principle of reciprocity, psychosocial criteria should be used, not to exclude patients, but instead to identify patients who need additional support. Finally, the authors discuss the requirements for and the proper assessment of informed and voluntary consent from patients being considered for xenotransplantation.

Patients with ischemic heart disease.

Ischemic heart disease (IHD) occurs when myocardial oxygen supply is not adequate for myocardial oxygen demand. Patients with IHD who are undergoing surgery are at risk for development of perioperative cardiac events (PCEs), and this risk depends on the type of surgery, the presence of clinical risk factors, and functional status of the patients. Appropriate perioperative management of medications such as dual antiplatelet therapy and ß-blockers has a significant impact on outcomes. Perioperative management decisions should be communicated clearly between the surgeon, cardiologist, and anesthesiologist in charge of the patient. Appropriate perioperative management reduces the incidence of PCEs.

Aortic valve bypass surgery: midterm clinical outcomes in a high-risk aortic stenosis population.

BACKGROUND: Aortic valve bypass (AVB; apicoaortic conduit) surgery relieves aortic stenosis (AS) by shunting blood from the apex of the left ventricle to the descending thoracic aorta through a valved conduit. We have performed AVB surgery as an alternative to conventional aortic valve replacement for high-risk AS patients. METHODS AND RESULTS: Between 2003 and 2007, 31 high-risk AS patients were treated with AVB surgery. Twenty-two patients (71%) were undergoing reoperation with patent coronary bypass grafts, and 5 (16%) had a porcelain ascending aorta. The average age was 81 years. Cardiopulmonary bypass was used for 19 of 31 patients (61%); the median duration of cardiopulmonary bypass was 19 minutes. Cross-clamp time for all patients was 0 minutes. Perioperative mortality was 13% (4 of 31 patients); no perioperative deaths occurred in the last 16 consecutive patients. One patient experienced a stroke related to intraoperative hypotension. No strokes have occurred during follow-up. Renal function was unchanged after AVB (preoperative creatinine, 1.3+/-0.5 mg/dL; postoperative creatinine, 1.2+/-0.5 mg/dL). The mean gradient across the native aortic valve decreased from 43.5+/-15 to 10.4+/-5.4 mm Hg. Echocardiographically determined conduit flow expressed as a percentage of total cardiac output was 72+/-12%. CONCLUSIONS: AVB surgery is an important therapeutic option for high-risk patients with symptomatic AS. Ventricular outflow is distributed in a predictable fashion between the conduit and the left ventricular outflow tract, and AVB surgery reliably relieves AS. Stroke and renal dysfunction were uncommon.

Aortic valve bypass for the high-risk patient with aortic stenosis.

BACKGROUND: Interest in percutaneous therapy of heart valve disease has focused attention on the high-risk patient with aortic stenosis. Aortic valve bypass (apicoaortic conduit) surgery is the construction of a vascular graft containing a bioprosthetic valve from the apex of the left ventricle to the descending thoracic aorta. We have undertaken a programmatic effort to perform aortic valve bypass surgery as an alternative to conventional aortic valve replacement in selected high-risk patients, and now report our recent experience. METHODS: Between April 2003 and May 2005, 14 patients with aortic stenosis underwent aortic valve bypass surgery at two institutions. All patients selected for aortic valve bypass surgery were deemed to be at very high risk for conventional aortic valve replacement. These patients represented 14 (5.8%) of all 243 patients undergoing isolated aortic valve surgery during the same time period. Mean Society of Thoracic Surgeons predicted risk for operative mortality (11%) was between the 90th and 95th percentile. RESULTS: Twelve of 14 patients had previous cardiac surgery with patent bypass grafts. Average age was 78 years. Mean aortic valve area was 0.68 cm2. All operations were performed through a left thoracotomy on the beating heart (cross-clamp time, 0 minutes). Cardiopulmonary bypass was used for 6 patients (median cardiopulmonary bypass time, 15 minutes). There were 2 perioperative deaths. Median postoperative length of stay was 9 days. Two noncardiac late deaths occurred. Nine of 10 surviving patients are functional class I and are living independently. Early postoperative echocardiography confirms excellent aortic valve bypass function with preservation of ventricular ejection performance. CONCLUSIONS: Treatment of high-risk aortic stenosis patients with aortic valve bypass surgery is promising. Avoidance of sternotomy and cardiopulmonary bypass supports broader application to moderate-risk patients with aortic stenosis and as a control arm for studies of novel interventional therapies.