Cardiac transplantation

The Disconnect Between Extracorporeal Circulation and the Microcirculation: A Review

Extracorporeal circulation (ECC) procedures, such as cardiopulmonary bypass (CPB) and extracorporeal membrane oxygenation (ECMO), take over the function of one or more organs, providing clinicians time to treat underlying pathophysiological conditions. ECMO and CPB carry significant mortality rates for patients, despite prior decades of research focused on the resulting failure of critical organs. Since the focus of these procedures is to support blood flow and provide oxygen-rich blood to tissues, a shift in research toward the effects of ECMO and CPB on the microcirculation is warranted. Along with provoking systemic responses, both procedures disrupt the integrity of red blood cells, causing release of hemoglobin (Hb) from excessive foreign surface contact and mechanical stresses. The effects of hemolysis are especially pronounced in the microcirculation, where plasma Hb leads to nitric oxide scavenging, oxidization, formation of reactive oxygen species, and inflammatory responses. A limited number of studies have investigated the implications of ECMO in the microcirculation, but more work is needed to minimize ECMO-induced reduction of microcirculatory perfusion and consequently oxygenation. The following review presents existing information on the implications of ECMO and CPB on microvascular function and proposes future studies to understand and leverage key mechanisms to improve patient outcomes.

Balancing the tug of war: intraoperative and postoperative management of multiorgan transplantation

PURPOSE OF REVIEW

Multiorgan heart transplants (MOHT) have steadily increased and account for approximately 4% of all heart transplants performed. Although long-term outcomes of MOHT are similar to heart transplant alone, perioperative management remains an issue with nearly double the rate of prolonged hospitalization. Better understanding of hemodynamic environments encountered and appropriate therapeutic targets can help improve perioperative management.

RECENT FINDINGS

Accurate and precise hemodynamic monitoring allows for early identification of complications and prompt assessment of therapeutic interventions. This can be achieved with a multimodal approach using traditional monitoring tools, such a pulmonary artery catheter and arterial line in conjunction with transesophageal echocardiography. Specific targets for optimizing graft perfusion are determined by phase of surgery and organ combination. In some circumstances, the surgical sequence of transplant can help mitigate or avoid certain detrimental hemodynamic environments.

SUMMARY

With better understanding of the array of hemodynamic environments that can develop during MOHT, we can work to standardize hemodynamic targets and therapeutic interventions to optimize graft perfusion. Effectively navigating this perioperative course with multimodal monitoring including transesophageal echocardiography can mitigate impact of complications and reduce prolonged hospitalization associated with MOHT.

Anesthesia for Heart Transplantation

This article seeks to evaluate current practices in heart transplantation. The goals of this article were to review current practices for heart transplantation and its anesthesia management. The article reviews current demographics and discusses the current criteria for candidacy for heart transplantation. The process for donor and receipt selection is reviewed. This is followed by a review of mechanical circulatory support devices as they pertain to heart transplantation. The preanesthesia and intraoperative considerations are also discussed. Finally, management after transplantation is also reviewed.

A review of cardiac transplantation

Perioperative anesthetic management for cardiac transplantation is reviewed. Recent developments in adult cardiac transplantation are noted. This review includes demographics and historical results, recipient and donor selection and evaluation, mechanical circulatory support and heart transplantation techniques, and patient management immediately postimplantation.

Assisting the failing heart

Anesthesiologists increasingly encounter patients who have a spectrum of heart failure ranging from stable chronic heart failure to acute heart failure to cardiogenic shock. Improved medical therapy has increased the survival of patients who have chronic heart failure but not of patients who have acute heart failure. New surgical techniques and mechanical devices may offer alternatives to certain patients who have refractory heart failure This article provides an overview of established and newer pharmacologic and nonpharmacologic therapies and surgical interventions to manage patients who have heart failure, including the perioperative management of heart transplantation and ventricular assist devices.

An Overview of Solid Organ Transplantation

Once a medical curiosity, solid organ transplantation is now a commonplace occurrence, with more than 27,000 procedures performed in the United States in 2004 alone. This article offers an overview of the various solid organ transplant procedures to provide a context within which subsequent articles on pulmonary complications can be viewed.