Repair of partial atrioventricular canal defect in adult patients: two-year follow-up outcomes of a retrospective study

During the study period, there were finally 46 patients enrolled in the study, of which 10(21.7%) were male patients. The characteristics of all the patients are summarized in Table 1. The mean weight and mean age at surgery were 53.1 ± 8.7 kg and 37.6 ± 12.4 years respectively. Besides ASD and mitral valve regurgitation, most adult PAVC patients had developed tricuspid regurgitation and some had developed arrythmia. There were 41 patients with TR, among which 21(45.7%) were mild, 15(32.6%) were moderate and 5(10.9%) were severe. All patients had MR, and 15(32.6%) were mild, 19(41.3%) were moderate and 12(26.1%) were severe. 8(17.4%) patients had atrial fibrillation, 2(4.3%) had third degree A-V block and 1(2.2%) had left bundle branch block. Transthoracic echocardiography demonstrated that the mean left atrial diastolic diameter was 40.1 ± 11.1 mm, the mean right atrial diastolic diameter was 54.2 ± 12.1 mm and the mean right ventricular diastolic diameter was 35.4 ± 6.4 mm. They all significantly exceeded reference value according to the result of t-test (P < 0.05) [5, 6]. However, it witnessed no dilatation of left ventricle with mean diastolic diameter of 42.3 ± 7.1 mm. According to NYHA (New York Heart Association) classification, the patients’ functional capabilities were divided into four classes, that was 5(10.9%) class I patients, 24(52.2%) class II patients, 16(34.8%) class III patients and 1(2.2%) class IV patient.

The operations of the 46 patients were mainly performed by 2 experienced surgeons (5 operations were by another two surgeons). Almost all operations were performed via median sternotomy except for two thoracoscopic PAVC repair surgeries. Cardiopulmonary bypass was routinely instituted via direct bicaval and aortic cannulation for each patient and St. Thomas cardioplegia was used at 20-min intervals as cold antegrade perfusion to protect myocardium during the surgery. Mean CBP time and mean cross-clap time were 73.3 ± 13.0 min and 48.8 ± 12.8 min respectively(Table 2). Mean minimal venous blood temperature during the cross-clap period was 32 ± 3.1 °C. Except for one suture closure, all the primum atrial septal defects were repaired with patch, 24(52.2%) patients used 0.6% glutaraldehyde soaked autologous pericardium patch, 10(21.7%) used Darcon patch and 11(23.9%) used tissue engineered bovine pericardium patch of Bal Medic. 10 patients had secundum ASDs, of which 1 was repaired with 0.6% glutaraldehyde soaked autologous pericardium, 2 were repaired with bovine pericardium and the rest were repaired with suture closure. There were 9 patients with PFOs and they were repaired with suture closure. All patch repaired ASDs were closed with McGoon procedure to protect the conducting bundles and there were no A-V block caused by the surgery. Most MRs were caused by leaflet cleft and some were caused by leaflet cleft and annular dilation. 40(87%) patients’ mitral valve clefts were repaired with intermittment suture, of which 6(13%) underwent mitral valve ring annuloplasty and 1 underwent posterior leaflet extension simultaneously. 6(13%) patients received mitral valve replacement though we tried valve repairs which ended in >moderate regurgitations because of valve incrassation and shrinkage. All mitral valve replacements were done prior to chest closure. 9(19.6%) patients underwent De Vega valvuloplasty for tricuspid valve regurgitation while 13 (28.3%) patients received ring annuloplasty. 2(4.3%) patients had muscular VSDs and both were repaired with suture closure. One patient underwent CoA(Coarctation of aorta) balloon dilatation prior to the PAVC repair.

The average collective duration of hospital stay was 15.0 ± 5.6 days. During this period, two patients still had atrial fibrillation which existed prior to surgery. Both patients received a cardioversion in operation but not successful. One patient with peri-operative A-V block and one with peri-operative left bundle branch block required pacemaker placement. Patients received proper treatment for the arrythmia. A patient had recurrent severe mitral valve regurgitation 2 days after the primary operation and received re-operation. We found three intermittent stiches on edge of the cleft teared off and repaired the cleft again and finally this patient discharged with mild regurgitation. One patient died for malignant ventricular arrythmia about 10 h after the surgery. The patient had atrial fibrillation prior to surgery and received successful mitral valve replacement, tricuspid repair and cardioversion. After the surgery, the patient had mild MR and mild TR and no longer had atrial fibrillation. The reason for the malignant arrythmia was not clear (Table 3). Every patient was routinely supported with mechanical ventilation, vasoactive drugs, diuretics and antibiotics if necessary. There were no severe infections, some patients had mild or moderate infections which recovered quickly after appropriate treatment and did not interfere with discharge.

The mean follow-up year was 2.96 ± 2.08 years. There was one early mortality and no late mortalities. One patient gained pericardial effusion 1 month after the surgery and underwent pericardiocentesis and drainage tube placement. Most recent echocardiographic findings about mitral valve revealed that there were 25(55.6%) patients with mild regurgitation, 3(6.7%) patients with moderate regurgitation and 2(4.4%) with severe regurgitation (Fig. 1 ). As for tricuspid valve regurgitation according to follow-up data, there were 33(73.3%) patients with none or trace regurgitations, 11(24.4%) with mild regurgitations and 1(2.2%) with moderate regurgitations (Fig. 2). The mitral regurgitations as well as the tricuspid regurgitations were significantly improved compared to preoperative situation (P < 0.05, tested by Pearson’s chi-squared test). Compared with preoperative NYHA functional classes, there were 34(75.6%) patients in class Iand 11(24.4%) patients in class II, which improved significantly(P < 0.05, tested by Pearson’s chi-squared test). It was found during follow-up that mean diameter of diastolic left ventricles relatively dilated to 46.5 ± 5.0 mm, which was 4.10 ± 8.14 mm larger than the preoperative size (P = 0.003)and still with normal limits. Mean diameter of diastolic right atriums and diastolic right ventricles recovered to 37.8 ± 7.5 mm and 19.8 ± 8.2 mm, decreased by 16.83 ± 11.83 mm (P < 0.001) and 15.62 ± 8.17 mm (P < 0.001) respectively(Table 4). But the mean diameter of diastolic left atriums was 41.3 ± 8.5 mm with no significant reduction(P = 0.519) (Fig. 3 ). A patient who received primary mitral repair underwent secondary mitral valve replacement for recurrent severe mitral valve regurgitation after discharge. Two patients underwent permanent pacemaker implantation for third degree A-V block and left bundle branch block. Both were transvenous. And all the reoperation patients had good follow-up outcomes with <moderate MRs and NYHA class I functional capabilities till the end of the retrospective study.