Asian Cardiovasc Thorac Ann 1998;6:17-22
© 1998 Asia Publishing EXchange Pte Ltd
The Influence of Prior Median Sternotomy on Outcome of Heart Transplantation
Nobuhiro Handa, MD,
Shafi Mussa, MB, BS,
W Michael O'Fallon, PhD1,
Richard C Daly, MD,
Christopher GA McGregor, MB, FRCS
Division of Thoracic and Cardiovascular Surgery
1 Section of Biostatistics Mayo Clinic and Foundation Rochester, Minnesota, USA
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Christopher GA McGregor, MB, FRCS Cardiothoracic Transplantation Mayo Clinic and Mayo Foundation 200 First Street SW Rochester, MN 55905, USA Tel:1 507 255 6038 Fax:1 507 255 4500 Email:mcgregor.christopher{at}mayo.edu
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ABSTRACT
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This study is a retrospective analysis of the influence of previous cardiac surgery on the outcome of heart transplantation in 118 consecutive recipients from January 1988 to December 1996. Group 1 consisted of 67 patients who had no previous sternotomy, group 2 was 33 patients who had one previous sternotomy, and group 3 was 18 patients who had two or more previous sternotomies. The three groups were demographically similar apart from the indication for transplantation and the sex distribution. Preoperative hemodynamic data, except systolic pulmonary artery pressure, were similar among the three groups. There was no significant difference in hospital mortality, 1-year and 5-year actuarial survival rates, incidence of renal dysfunction requiring dialysis, prolonged respiratory support, elevated total bilirubin, re-exploration for bleeding, incidence of mediastinitis, or postoperative hospital stay between the groups. The rejection-free and infection-free survival rates were similar in the three groups. However, previous sternotomy resulted in significantly longer cardiopulmonary bypass times and increased requirement for blood and blood products. The use of a cell saver limited the need for stored red blood cells. This study demonstrated no survival disadvantage of previous sternotomy in patients undergoing heart transplantation.
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INTRODUCTION
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The steady improvement in short-term and long-term survival following heart transplantation has led to 1-year and 5-year survival rates of 79% and 63% respectively, according to the Registry of the International Society of Heart and Lung Transplantation.1 An increasing number of patients with end-stage heart failure are now waiting for heart transplantation, which includes a significant proportion of potential recipients who have a history of previous cardiac procedures.2 The influence of a previous cardiac operation on short-term and long-term survival in heart transplant recipients remains controversial.3–7 In addition to the perioperative risks associated with redo sternotomy and dissection of dense adhesions, it has been suggested that an increased risk of rejection might also be expected because of an increased requirement of blood products perioperatively.4,5 As the supply of donor organs is limited, optimal allocation of donor organs compatible with a good outcome is desirable. If previous cardiac surgery significantly increased morbidity and mortality after heart transplantation this factor should be considered in patient selection. The purpose of this study was to assess the effect of a previous cardiac procedure on mortality and morbidity following heart transplantation.
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METHODS
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From January 1988 to December 1996, all 118 consecutive isolated heart transplant procedures were analyzed. Heart transplantation was the primary cardiac procedure (no previous sternotomy) in 67 patients (group 1). Thirty-three transplant recipients had one previous cardiac procedure requiring sternotomy (group 2). Eighteen patients had two or more previous cardiac procedures (group 3). For this retrospective study, operative notes, anesthesia records, clinical case histories, transfusion records, and laboratory investigations were reviewed. Follow-up data were collected from clinical medical records. A total of 97 clinical and hemodynamic variables were entered into a computerized database and analyzed.
Heart transplantation was undertaken using standard techniques.8 All patients who required bicaval anastomosis because of congenital anomalies had conventional biatrial anastomoses, except for one patient in group 2. For redo sternotomy, both sides of the groin were prepared for femoral cannulation. This was needed in 6 patients in group 2 and 2 patients in group 3. An extra assistant surgeon was scrubbed in redo situations to facillitate femorofemoral bypass if necessary. Redo sternotomy was performed using an oscillating saw. A standard aprotinin protocol was used in the majority of patients in group 2 (32/33) and group 3 (17/18). An additional 30 minutes was reserved for dissection of the mediastinum in redo recipients when synchronizing donor and recipient operations. The ischemic time was defined as the period between aortic cross-clamping of the donor heart and aortic declamping of the recipient. An extracellular crystalloid cardioplegic solution (Plegisol; Abbott Laboratories, Abbott Park, IL, USA) was employed for cardiac preservation.
The patients had induction therapy with 2.5 mg OKT-3 daily for 14 days and conventional triple-drug therapy (cyclosporine, azathioprine, and prednisone) for immunosuppression. The cardiac biopsy schedule was: once a week for 6 weeks; once every 2 weeks from 6 weeks to 3 months; and once a month between 3 and 6 months. Thereafter, surveillance biopsy was performed once every 3 months. Rejection was graded according to the histopathologic grading system of the International Society of Heart and Lung Transplantation.9 Grade II or more rejection was treated with augmented immunosuppression.
Patient groups were compared with regard to several characteristics using Wilcoxon's rank sum test for continuous variables (such as age) and Fisher's exact test for categorical variables. Rates of occurrence of certain events (death, rejection, infection) were estimated using the KaplanMeier product limit method and the groups were compared using log-rank tests.
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RESULTS
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PREOPERATIVE DATA ASSESSMENT
The demographic characteristics of the three groups are shown in Table 1
. In comparing preoperative variables among the groups, no significant difference was found in age, status at transplant (status 1 versus status 2), serological status of cytomegalovirus, Epstein-Barr virus, or toxoplasmosis. All three groups were predominantly male but there were significant differences in the male to female ratios within the groups. There was no significant difference in the number of patients who were anticoagulated preoperatively with warfarin or in the mean prothrombin times and activated partial thromboplastic times.
Recipient diagnoses are shown in Table 2. Idiopathic cardiomyopathy was the most common diagnosis in group 1, whereas ischemic cardiomyopathy was the most common diagnosis in groups 2 and 3. In group 2, coronary artery bypass grafting was the most common reason for a previous sternotomy (52%). Other operations were valve replacement or repair, correction of congenital heart disease, insertion of mechanical circulatory support, and septal myectomy. In group 3, 16 patients had two previous sternotomies, one patient had three sternotomies, and one had four previous sternotomies. Forty-four percent of patients in this group had undergone coronary artery bypass grafting twice, 39% of patients had multiple sternotomies for correction of congenital heart abnormalities. Preoperative hemodynamic data are detailed in Table 3. Pulmonary systolic pressure was higher in group 1 compared with group 2. The other parameters such as transpulmonary pressure gradient, cardiac index, and pulmonary vascular resistance index were similar in the three groups. The three groups were also similar with respect to the age and sex of the donors.
SURGERY
Variables associated with surgery are shown in Table 4. Graft ischemia times were similar in groups 1, 2 and 3. However, cardiopulmonary bypass times and operation times were significantly longer in groups 2 and 3 than in group 1. Transfusion of red blood cells including those from the intraoperative cell saver and total blood products during the first 48 hours were significantly higher in groups 2 and 3 than in group 1. The mean total red blood cells required by group 1 was 5.5 ± 3.3 units, the mean for group 2 was 9.2 ± 10.3 units, and for group 3 it was 10.0 ± 5.9 units. The transfusion of total blood products in the first 48 hours for group 1 was 8.6 ± 9.4 units, for group 2 it was 31.7 ± 54.9 units, and for group 3 it was 27.4 ± 21.6 units. Excluding units from the cell saver, the actual requirements for preoperatively stored autologous or homologous red blood cells were not significantly different in the three groups.
OUTCOME
Overall hospital mortality was 2 cases out of 118 (1.7%) and there was no significant difference between the three groups (1.5% versus 0% versus 5.6%). Postoperative complications are detailed in Table 5. The most common postoperative complications were bradycardia requiring permanent pacemaker placement, respiratory insufficiency requiring prolonged ventilatory support (intubation for longer than 72 hours), and hyperbilirubinemia. No significant differences were found between the three groups in any individual complication. Reexploration for bleeding was a rare complication in this series occurring in only 2 cases. No significant differences were observed in duration of intubation or hospital stay.
Kaplan-Meier survival analysis are shown in Figure 1. One-year and 5-year survival rates showed no significant difference between the three groups. The causes of late death are shown in Table 6. Rejection was the cause of late death in one patient in group 1 and one in group 2. Seven patients died in group 1 during a total follow-up of 2937 months. Two patients died of malignancy; one with lung cancer and the other with lymphoma. Two other patients died from infectious complications; one from aspergillosis, the other from liver failure associated with acute hepatitis C originating from the donor organ. One patient developed progressive dementia and the family decided to cease immunosuppressive therapy. The only late death in group 3 was a sudden death of unknown cause.
The rejection-free survival curves are shown in Figure 2. No significant differences were observed between the three patient groups. The proportion of patients experiencing a rejection episode within one year was also similar among the three groups. Table 5
includes infectious complications during hospitalization. Cytomegaloviremia and bacterial pneumonitis were the most common infections in this study. One case of mediastinitis was observed in group 3 but none in groups 1 and 2. Infection-free survival curves are shown in Figure 3. No significant difference was observed between the three groups.
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Figure 2. Previous sternotomy and cardiac transplantation: Kaplan-Meier rejection-free survival analysis.
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Figure 3. Previous sternotomy and cardiac transplantation: Kaplan-Meier infection-free survival analysis.
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DISCUSSION
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Heart transplantation is widely accepted as a routine therapeutic modality for selected patients with end-stage heart failure. According to the Registry of the International Society for Heart and Lung Transplantation more than 3000 heart transplants worldwide have been reported annually since 1988.1 However, it is clear that the number of cardiac transplant operations has reached a plateau because the number of available donor organs has continued to be limited over the last five years.9 Continuous improvement in heart transplant outcomes resulting in 1-year and 3-year survival rates of 79% and 71% respectively, have widened the indication for this procedure and an increasing number of patients with end-stage heart failure are waiting cardiac transplantation.1,2 As the supply of donor hearts is limited, risk stratification is helpful in optimizing the use of this precious resource. Risk factors for 1-year heart transplantation mortality analyzed for USA transplant patients did not include a previous history of cardiac surgery.1 However, it is accepted that second operations in general cardiac surgery carry an increased risk.10,11 The effect of previous cardiac surgery on mortality and morbidity in heart transplant patients is still controversial. Two previous studies suggested that previous cardiac procedures increased the rates of early death and postoperative complications,4,5 whereas other studies failed to confirm these findings.3,6,7
The present study did not show any particular increased risk in transplant recipients with previous cardiac surgery in terms of short-term morbidity and mortality as well as long-term survival. Heart transplant recipients who have cardiomegaly and poor cardiac function are at risk of direct cardiac injury during the initial dissection. This is reflected in the longer surgical times and the longer cardiopulmonary bypass times seen in this study. In addition, patients with previous cardiac surgery required increased amounts of red blood cells and blood products in the perioperative period. Interestingly, total requirements for autologous or homologous stored blood were not different between the groups. Therefore, the use of a cell saver is important in reducing transfusion requirements in redo heart transplantation. Previous reports mentioned that reexploration for bleeding was more frequent in patients with prior cardiac surgery.3–5 This was not found in our study. Speculation that increased requirements for blood products, reexploration, and postoperative mediastinitis would be encountered was not supported by our findings. Only two patients needed re-exploration for excessive bleeding after surgery and only one patient developed mediastinitis. Aprotinin was used in the majority of patients in groups 2 and 3 and seemed to be effective in reducing bleeding and requirements for blood products. Other types of infectious complications such as pneumonitis and cytomegalovirus infection were observed in a small number of cases perioperatively but no differences were detected among the three groups.
Bradycardia requiring permanent pacemaker placement, prolonged respiratory support, and hyperbilirubinemia were the most common perioperative complications. The use of older donors in our series resulted in the increased need for permanent pacemaker insertion, but there was no difference between the groups.12 Length of hospital stay was similar among the three groups. Uthoff and colleagues4 suggested that poorer outcomes in patients who had previous cardiac procedures were due to early deaths from graft failure. In our study, right heart failure was an infrequent postoperative complication and it was not associated with hospital mortality. Careful measurement of pulmonary vascular resistance preoperatively is critical in assessing the reversibility of preoperative pulmonary hypertension.13
With respect to long-term follow-up data, no significant differences were observed among the three groups in terms of survival analysis and infection-free or rejection-free survival analyses. One limitation in this study was that the three groups had different preoperative diagnoses. No patient with congenital heart disease had heart transplantation as a primary procedure. This study shows that similar short-term and long-term results can be achieved in patients with previous open-heart surgery compared to those having first-time cardiac operations. Therefore, prior cardiac surgery is not a contraindication for heart transplant candidacy.
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REFERENCES
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Hosenpud JD, Novick RJ, Bennett LE, et al. The Registry of the International Society for Heart and Lung Transplantation: thirteenth official report 1996. J Heart Lung Transplant
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Lytle BW, Loop FD, Cosgrove DM, et al. Fifteen hundred coronary reoperations. Results and determinants of early and late survival. J Thorac Cardiovasc Surg
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Chau EMC, McGregor CGA, Rodeheffer RJ, et al. Increased incidence of chronotropic incompetence in older donor hearts. J Heart Lung Transplant
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Chau EMC, Bailey KR, Mahoney DW, et al. Predictors of reversibility of pulmonary hypertension in cardiac transplant recipients in the first postoperative year. Circulation
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ABSTRACT
INTRODUCTION
