Physiologic Changes in the Heart Following Cessation of Mechanical Ventilation in a Porcine Model of Donation After Circulatory Death: Implications for Cardiac Transplantation.

Hearts donated following circulatory death (DCD) may represent an additional source of organs for transplantation; however, the impact of donor extubation on the DCD heart has not been well characterized. We sought to describe the physiologic changes that occur following withdrawal of life-sustaining therapy (WLST) in a porcine model of DCD. Physiologic changes were monitored continuously for 20 min following WLST. Ventricular pressure, volume, and function were recorded using a conductance catheter placed into the right (N = 8) and left (N = 8) ventricles, and using magnetic resonance imaging (MRI, N = 3). Hypoxic pulmonary vasoconstriction occurred following WLST, and was associated with distension of the right ventricle (RV) and reduced cardiac output. A 120-fold increase in epinephrine was subsequently observed that produced a transient hyperdynamic phase; however, progressive RV distension developed during this time. Circulatory arrest occurred 7.6±0.3 min following WLST, at which time MRI demonstrated an 18±7% increase in RV volume and a 12±9% decrease in left ventricular volume compared to baseline. We conclude that hypoxic pulmonary vasoconstriction and a profound catecholamine surge occur following WLST that result in distension of the RV. These changes have important implications on the resuscitation, preservation, and evaluation of DCD hearts prior to transplantation.

Hearts from DCD donors display acceptable biventricular function after heart transplantation in pigs.

Cardiac transplantation is in decline, in contrast to other solid organs where the number of solid organ transplants from donors after circulatory death (DCD) is increasing. Hearts from DCD donors are not currently utilized due to concerns that they may suffer irreversible cardiac injury with resultant poor graft function. Using a large animal model, we tested the hypothesis that hearts from DCD donors would be suitable for transplantation. Donor pigs were subjected to hypoxic cardiac arrest (DCD) followed by 15 min of warm ischemia and resuscitation on cardiopulmonary bypass, or brainstem death (BSD) via intracerebral balloon inflation. Cardiac function was assessed through load-independent measures and magnetic resonance imaging and spectroscopy. After resuscitation, DCD hearts had near normal contractility, although stroke volume was reduced, comparable to BSD hearts. DCD hearts had a significant decline in phosphocreatine and increase in inorganic phosphate during the hypoxic period, with a return to baseline levels after reperfusion. After transplantation, cardiac function was comparable between BSD and DCD groups. Therefore, in a large animal model, the DCD heart maintains viability and recovers function similar to that of the BSD heart and may be suitable for clinical transplantation. Further study is warranted on optimal reperfusion strategies.

Cardiopulmonary bypass and deep hypothermic circulatory arrest in a massively obese patient.

As a consequence of the rising global prevalence and magnitude of obesity, a greater proportion of patients presenting for cardiac surgery is morbidly obese. Being overweight (body mass index; BMI 25-29.9 kg/m(2)) or obese (BMI 30-35 kg/m(2)) appears to confer some survival benefit following cardiac surgery. By contrast, morbid obesity (BMI >40 kg/m(2)) is associated with an increased likelihood of postoperative complications and prolonged intensive care unit and hospital length of stay. The physical difficulties encountered when managing this group of patients is exemplified by those undergoing complex, multiple procedures requiring prolonged cardiopulmonary bypass (CPB) and deep hypothermic circulatory arrest (DHCA). We present the successful management of a massively obese 19-year-old male (BMI 45 kg/m(2)) with Marfan's syndrome who required aortic root and arch replacement under DHCA. The selection of extracorporeal circuit components to accommodate a large circulating volume and permit high CPB flow rates (>9 l/min) is discussed.

Aortic valve replacement for late infective endocarditis after heart-lung transplantation.

Infective endocarditis is a rare but life-threatening complication of heart and heart-lung transplantation. We describe a 32-year-old woman who developed aortic valvular endocarditis following heart-lung transplantation. Enterococcus was the infective organism. The patient's condition was successfully managed using prolonged intravenous antibiotic therapy and aortic valve replacement.

Lethal mesenteric ischaemia after cardiopulmonary bypass: a common complication?

OBJECTIVES: The purpose of the study was twofold: (1) to identify the incidence of acute mesenteric ischaemia (A.M.Isc.) following cardiopulmonary bypass and (2) to identify factors associated with its development. METHODS: A retrospective review of all autopsy reports from 1st January 1994 to 31st December 2000 was undertaken. Fifty-two patients were identified with acute mesenteric ischaemia at post-mortem following cardiac surgery. Demographic, pre-, intra- and post-operative variables were collected from their case notes. Four age, sex and period matched controls [n=208 (4 x 52)] were randomly selected for each case. Conditional logistic regression was used to compare the cases and controls. RESULTS: A total of 11,202 patients underwent surgery requiring cardiopulmonary bypass (CPB) during the study period with an overall mortality rate of 3%. The autopsy rate was 95% throughout the study period. From autopsy reports 52 patients (corrected for autopsy rate: 0.49% of group) were identified with A.M.Isc. Comparing controls with A.M.Isc. cases by univariate analysis, significant associations (P

Atrial transplantation for recurrent cardiac sarcoma.

Cardiac transplantation for sarcomas has met with little success and the surgical treatment remains controversial. We describe the case of a 56-year-old woman who was referred for transplantation after two procedures in which undifferentiated atrial sarcoma was locally excised successfully. The patient underwent atrial homograft transplantation, the first reported to date. Advantages of the procedure include wide atrial resection and no need for immune suppression.

Improved outcome with organs from carbon monoxide poisoned donors for intrathoracic transplantation.

BACKGROUND: The success of intrathoracic organ transplantation has lead to a growing imbalance between the demand and supply of donor organs. Accordingly, there has been an expansion in the use of organs from nonconventional donors such as those who died from carbon monoxide poisoning. We describe our experience with 7 patients who were transplanted using organs after fatal carbon monoxide poisoning. METHODS: A retrospective study of the 1,312 intrathoracic organ transplants between January 1979 and February 2000 was completed. Seven of these transplants (0.5%) were fulfilled with organs retrieved from donors after fatal carbon monoxide poisoning. There were six heart transplants and one single lung transplant. The history of carbon monoxide inhalation was obtained in all of these donors. RESULTS: Five of 6 patients with heart transplant are alive and well with survival ranging from 68 to 1,879 days (mean, 969 +/- 823 days). One patient (a 29-year-old male) died 12 hours posttransplant caused by donor organ failure. The patient who had a right single lung transplant did well initially after the transplant, but died after 8 months caused by Pneumocystis carinii pneumonia. All those recipients who were transplanted from carbon monoxide poisoned donors and ventilated for more than 36 hours, survived for more than 30 days. Moreover, these donors were assessed and optimized by the Papworth donor management protocol. CONCLUSIONS: Carbon monoxide poisoned organs can be considered for intrathoracic transplantation. In view of the significant risk of donor organ failure, a cautious approach is still warranted. Ideally, the donor should be hemodynamically stable for at least 36 hours from the time of poisoning and on minimal support. A formal approach of invasive monitoring and active management further improves the chances of successful outcome.

Two-decade analysis of cardiac storage for transplantation.

OBJECTIVE: Cardiac storage solutions and methods remain unstandardized. We have surveyed the literature to establish how the subject has progressed, addressing models of preservation and measures of outcome. Since a lot of the literature on cardiac storage is generated in the laboratory, we were particularly interested to evaluate to what extent bench work finds its way into and clinical practice. The discussion focuses in addition to new areas of research and introduces the concept of integrated organ preservation. METHODS: Five representative journals (J Thorac Cardiovasc Surg, Circulation, J Heart Lung Transplant, Eur J Cardio-thorac Surg and Ann Thorac Surg) were searched by hand for papers published between 1980-1999. All laboratory, animal experimental and clinical studies focused on prolonged cardiac preservation and storage were selected. RESULTS: Two hundred and forty-nine publications were identified using preset criteria. Of these, 196 (79%) were studies performed in animal models and 10 (4%) were experiments carried out on animal tissue. One hundred and five experiments (42% of all studies) were performed in small animals. The most common animal model was of ischemia followed by ex vivo reperfusion (121 studies, 49% of publications). The measures of outcome were classified as biochemical, functional, morphologic and endothelial; the majority of studies had one (48%) or two (40%) end-points. Twenty-five studies (10%) had endothelial measures of outcome, alone or in combination with other types of outcomes. Human clinical work was represented by 34 (14%) studies of clinical transplantation and nine (4%) experiments on human tissue only. There were five randomized clinical trials, representing 2% of all papers and 15% of all clinical research. CONCLUSION: In conclusion, most of the surgical publications on prolonged cardiac preservation result from animal research. Small animal models of ex vivo ischemia and reperfusion are predominant.

Effect of surgical training on outcome and hospital costs in coronary surgery.

BACKGROUND: There is a perceived conflict between the need for service provision and surgical training within the National Health Service (NHS). Trainee surgeons tend to be slower (thereby reducing theatre throughput), and may have more complications (increasing hospital stay and costs). OBJECTIVE: To quantify the effect of training on outcome and costs. DESIGN: Data on 2740 consecutive isolated coronary artery bypass (CABG) operations were analysed retrospectively. Redo and emergency procedures were excluded. The seniority of the operating surgeon was related to operating times, risk stratified outcome, and overall hospital costs. SETTING: Regional cardiothoracic surgery unit. MAIN OUTCOME MEASURES: Postoperative mortality; hospital costs. RESULTS: Consultants, senior trainees, intermediate trainees, and junior trainees performed 1524, 759, 434, and 23 procedures, respectively. Trainees at the three different levels were directly supervised by a consultant in 55%, 95%, and 100% of cases. The unadjusted mortalities were 3.2%, 2.0%, 2.3%, and 4.3%, respectively (NS). There were no significant differences between the groups with respect to time in the intensive care unit and length of hospital stay. The mean cost per patient was pound6619, pound6572, pound6494, and pound6404 (NS). CONCLUSIONS: Trainees performed 44.4% of all CABG operations. There was no detrimental effect on patient outcome, length of hospital stay, or overall hospital costs. There need be little conflict between service and training needs, even in hospitals with extensive training programmes.

Heart-lung transplantation for Eisenmenger syndrome: early and long-term results.

BACKGROUND: Heart-lung transplantation (HLT) for Eisenmenger syndrome (ES) provides superior early and intermediate survival when compared with other forms of transplantation. The early risk factors and long-term outcome of HLT for ES are less well defined. METHODS: We analyzed 263 patients who had undergone HLT at our institution during more than 15 years. Fifty-one consecutive patients with ES who underwent HLT, 33 (65%) of which had simple anatomy, were compared with 212 cases having HLT for other indications (non-ES). RESULTS: Female sex and previous thoracotomy were more prevalent in the ES group. Patients with ES had greater postoperative blood loss and returned more frequently to the operating room for control of bleeding. There were 8 (16%) early deaths in the ES group compared with 27 (13%) in non-ES (p = 0.65). One-, 5-, and 10-year survival rates for ES were 72.6%, 51.3%, and 27.6%, respectively, compared with non-ES of 74.1%, 48.1%, and 26.0%, respectively, and there was no difference in survival overall (p = 0.54). Among ES patients, previous thoracotomy was a risk factor for hospital death. A subgroup analysis based on simple versus complex type of ES did not show statistically significant differences in terms of postoperative course or early or late survival. CONCLUSIONS: Heart-lung transplantation is a successful procedure for ES. Despite a greater frequency of risk factors and a more difficult operative course, early and late outcome with HLT is comparable to non-ES recipients.

Relocation of the internal mammary artery graft in a case of coronary-subclavian steal.

Reverse flow in the internal mammary artery coronary graft in the presence of subclavian stenosis is rare. We describe a 67-year-old man who 7 years after coronary artery surgery was admitted with left subclavian artery stenosis and retrograde flow in the pedicled left internal mammary artery graft. Subsequent redo triple coronary artery bypass grafts included regrafting the left internal mammary artery graft to a new vein conduit.