Complete transposition of the great arteries with severe pulmonary hypertension increses late mortality after artery switch operation

Objective The postoperative outcomes of transposition of the great arteries with severe pulmonary hypertension (PH) are still controversial. Based on relative large data, we evaluated the relationship between preoperative pulmonary hypertension and postoperative early and midterm clinical outcomes. Methods In this retrospective study, a cohort of consecutive patients with TGA was studied. One hundred and one patients underwent artery switch operation between February 2004 and October 2007. Preoperative medical records were reviewed. The mean follow-up period was 22.6 months. All artery switch operations were performed through a median sternotomy utilizing extracorporeal circulation. Deep hypothermia and circulatory arrest were used in 6 patients. After sternotomy, pulmonary arterial pressure was measured directly. According preoperative mean pulmonary pressure ( mPAP), patients were divided into three groups: normal group ( mPAP ＜25mmHg, n =43), moderate PH group ( mPAP between 25 to 50mmHg, n = 47) and severe PH group ( mPAP ≥50mmHg, n = 11 ). The methods of coronary anastomosis were "open trap door" ( 39 cases), "bay window" (61 cases) and "pulmonary artery tunnel" ( 1 case)techniques. Besides repairing of atrial septal defect and ventricular septal defect, ligation of patent ductus arteriosus, concomitsnt operations also involved mitral valvuloplasty (5 patients), tricuspid valvuloplasty (2 patients), pulmonary valvuloplasty (5 patients), pulmonary artery transplantation ( 1 patient ), subvalvular membrane resection ( 2 patients), widening of the right ventricular outflow tract ( 1 patient ) and collateral circulation occlusion ( 1 patient). The early and late postoperative results were compared among different groups. Results After operation, mPAP in severe PH group decreased from (61.2 ± 8.6 ) mmHg to ( 34.6 ± 13.6 ) mmHg( P ＜ 0.01 ). In moderate PH group it decreased from ( 34.5 ± 6.7 ) mmHg to ( 21.3 ± 5.6) mmHg( P ＜ 0.0l ). mPAP was not significantly changed in the control group. Operative mortality was 7.9% ( 8 patients ).The causes of early death were low output syndrome in 3 patients, septicemia in 4, central nervous system complications in 1.There was no difference in the postoperative complication rates among three groups. Also, no significant differences were found between groups regarding the early operative mortality (control group: 7.0%, moderate PH group: 8.5%, severe PH group:9.1%, P = 0.953 ). Combined abnormity contributed to postoperative death. Patients with ventricular septal defect and patent ductus arteriosus had a higher mortality rate. During follow-up 8 patients died: 5 in control group ( 11.6% ), 5 in moderate PH group ( 10.6% ) and 6 in severe PH group (54.5% ), P ＜ 0.01. Causes of midterm death were sudden death in 10, progressive heart failure in 4, pneumonia in 2. The rates of midterm mortality of the three groups were significantly different ( 11.6%,10.6% and 54.5% for control, moderate PH and severe PH group, respectively, P = 0.001 ). Kaplan-Meier survival analysis for patients with different age groups showed that survival rate in group with age older than 1 year was lower ( P = 0.029 ).Conclusion In TGA/PH patients, mPAP lower than 50 mmHg is suitable for artery switch operation and can get satisfying postoperative outcomes. If mPAP higher than 50 mmHg, even though the operation may decrease the pulmonary pressure, radical artery switch operation should not be recommended because of higher late mortality. Key words: Transposition of great vessels; Cardiac surgical procedures; Hypertesion, pulmonary; Follow-up studies