Intensive care of the cardiac transplant recipient

Perioperative care of heart transplant recipients undergoing non-cardiac surgery

The life expectancy of patients with end-stage heart disease undergoing Orthotopic Heart Transplantation (OHT) has increased significantly in the recent decades since its original introduction into the medical practice in 1967. Substantial advances in post-operative intensive care, surgical prophylaxis, and anti-rejection drugs have clearly impacted survivability after OHT, therefore the volume of patients presenting for non-cardiac surgical procedures is expected to continue to escalate in the upcoming years. There are a number of caveats associated with this upsurge of post-OHT patients requiring non-cardiac surgery, including presenting to healthcare facilities without the resources and technology necessary to manage potential perioperative complications or that may not be familiar with the care of these patients, facilities in which a cardiac anesthesiologist is not available, patients presenting for emergency procedures and so forth. The perioperative care of patients after OHT introduces several challenges to the anesthesiologist including preoperative risk assessments different to the general population and intraoperative management of a denervated organ with altered response to medications and drug-drug interactions. The present review aims to synopsize current data of patients presenting for non-cardiac surgery after OHT, surgical aspects of the transplant that may impact perioperative care, physiology of the transplanted heart as well as anesthetic considerations.

Anesthetic considerations in the patient with a heart transplant

As programs to increase the awareness of organ donation grow, more patients undergo cardiac transplantation. Because immunosuppressive therapy and postoperative care are improved, the 1-year survival rate of these patients has increased to more than 80%. Not surprisingly, these patients may, either coincidentally or as a result of medications, require other procedures using anesthesia, frequently at hospitals other than the highly specialized institution that performed the transplant. Because the denervated heart responds differently than the normal heart to many perioperative drugs, physicians, including cardiologists who are frequently consulted preoperatively, must have a special awareness of the particular problems in this group of patients.

Anesthesia for Noncardiac Surgery in Pediatric Patients Following Cardiac Transplantation

Pediatric cardiac transplantation has been performed with increasing frequency to treat hypoplastic left heart syn drome and other types of congenital heart disease. A large number of these patients will require anesthesia posttrans plantation for noncardiac surgery. A review of our series of 92 anesthetics in 46 patients has better defined periopera tive risk factors, anesthetic management, common surgical procedures, and complications associated with noncardiac surgery in posttransplantation patients. Anesthetic manage ment concerns include allograft coronary artery disease, graft rejection, denervation, cardiac dysrhythmias, immuno suppression, cyclosporine-induced hypertension, drug inter actions, renal dysfunction, and intravenous access prob lems. Preoperative evaluation must include the possibility and definition of these problems. Medically stable patients undergoing noncardiac/nonthoracic surgery after cardiac transplantation undergo the same surgical procedures as similarly aged nontransplantation patients. Similar induc tion techniques can be used as in nontransplantation pa tients. These patients may also be scheduled for same-day surgery if other significant medical problems are not present and the difficulty of the surgery is compatible with an out patient setting. Patients with more complex medical prob lems, including chronic rejection, significant coronary artery disease, or a history of congestive failure may need over night monitoring in a hospital setting despite that only a minor surgical procedure is being performed.

Anaesthesia for non-cardiac surgery in heart-transplanted patients

This review documents the anaesthetic management, haemodynamic function and outcome in 18 of 86 heart-transplanted recipients, who returned for 32 non-cardiac surgical procedures at the Toronto Hospital from 1985 to 1990. General anaesthesia was administered in eight of the 27 elective operations and four of the five emergency operations. Induction medications included thiopentone (2-4 mg.kg-1), fentanyl (1-7 micrograms.kg-1) and succinylcholine (1-1.5 mg.kg-1). Anaesthesia was maintained with a combination of oxygen/nitrous oxide and isoflurane or enflurane. Muscle relaxation was maintained with vecuronium or pancuronium. No delayed awakening or unplanned postoperative ventilation was observed. Neurolept-anaesthesia was administered to 63.0% and 20.0% of the elective and emergency operations, respectively. The anaesthetics included fentanyl (25-100 micrograms) and midazolam (0.5-1.5 mg) or diazemuls (2.5-5.0 mg). Spinal anaesthesia (75 mg lidocaine) was administered to only two of the 27 elective operations. No important haemodynamic changes were observed in any anaesthetic group, but lower systolic BP was found after induction and during maintenance periods in the patients who received general anaesthesia than in those who received neurolept-anaesthesia. However, no anaesthesia-related morbidity or mortality was noted. This suggests that general, neurolept- and spinal anaesthesia do not affect haemodynamic function or postoperative outcome in heart-transplanted recipients undergoing subsequent non-cardiac surgery.

[Anesthesia for non-specific surgery in a post-transplantation patient]

The increase of non specific surgeries in transplanted patients may be related to the better survival achieved by the efficacy of immunosuppressive therapy and improved surgical and intensive care conditions. Therefore, the anaesthetist may be mandated to give anaesthesia in such patients, treated in hospitals which are not involved in transplantation procedures. The ignorance of the main physiologic and pharmacological changes in the new grafted organ as well as the knowledge of high risks of rejection or infection contribute to the anxiety often encountered in front of these patients. The denervated heart is unable to respond to stimulations requiring the integrity of autonomic neural mechanisms. Modulation of cardiac output depends on intrinsic activity (Frank-Starling mechanism) and therefore of end diastolic volume (preload). The denervated transplanted lung shows inability to elicit cough reflex; the latter is totally abolished in case of tracheal anastomosis. These physiologic changes have no deleterious effects on early cardiac and pulmonary functions following transplantation. In the same way, renal, liver or pancreatic functions are restored after respective replacement. However chronic rejection occurs frequently in 50% of patients in a mean time of 5 years following surgery except for liver transplanted patients which seem to be better protected. It results in a progressive decrease in organ function tests. The preoperative assessment requires primary contact with the transplant center. This communication should give precious information about the last biological and functional results as well as about the immunosuppressive therapy. Standard preoperative investigations include measurements of haemoglobin, urea, electrolyte and creatinine concentrations, liver tests, ECG, chest X-ray and coagulation pattern. Previsible difficult intubation should be detected in case of previous pancreas transplantation. Immunosuppressive therapy and other treatments should not be disrupted until surgery. Usual premedication may be used. Previsional peroperative transfusion requires specific packed red blood cells, fresh frozen plasma and platelets in order to reduce CMV contamination and GVH reactions. Locoregional or general anaesthesia may be used with respect to usual contraindications. Special attention should be given in cardiac transplanted patients in order to maintain adequate preload. As atropine is ineffective, bradycardia may be treated by isoprenaline. Patients with lung transplants require a reduction of vascular loading and of hydratation and early postoperative pulmonary physiotherapy. Pancreas transplanted patients often suffer from severe cardiac diseases (coronaropathy). The immunosuppressive therapy modifies the pharmacological behavior of many anaesthetic agents. Ciclosporine enhances mainly the effects of muscle relaxants. Peroperative invasive monitoring requires full aseptic techniques. Invasive monitoring should be discussed in terms of benefit-risk ratio.(ABSTRACT TRUNCATED AT 400 WORDS)