Atrioventricular septal defects (AVSDs) are common among congenital heart diseases and they account for 3% of all major congenital cardiac defects. AVSDs are classified into three categories: complete, partial and transitional . Operation via median sternotomy to repair AVSDs was first introduced in 1955 . As more than 60 years passed, the surgical technique and medical technology have advanced . Partial atrioventricular canal defect repair is relatively mature now. In open heart surgery, the surgical procedures mainly encompass mitral valve cleft suture and primum atrial septal defect repair [3, 10, 11]. According to the reports, most patients only need the two procedures in surgery and the survival following surgeries revealed excellent results.
The optimal timing of elective surgery repair remains controversial. Although different centers have not come to an agreement, most of the reports state that the optimal time for repair is during the early childhood [4, 10]. Therefore, most patients undergo operation in childhood. There is a lack of reports about the outcomes of patients who undergo PAVC operation when they are already adults. This retrospective study was aimed at reviewing the mid-term survival, reoperation incidence and complications caused by delayed operation in adult PAVC patients.
A long-term retrospective study by Najdawi et al. reported a 2% mortality rate in 30 days and a 6% mortality rate 5 years after surgery . A single-institute retrospective study including 86 patients demonstrated two deaths in long-term follow-up . Most of the studies about PAVC operation revealed good follow-up results [3, 4, 12, 13]. In our study, there was no late mortality. One patient died at the night of operation because of malignant ventricular arrythmia. The mortality rate was 2.2%. Though delayed diagnoses and treatments, results of our study were very good.
During the follow-up period, 4(8.7%) patients need reinterventions: 2 for permanent pacemaker implantation and 2 for recurrent severe mitral valve regurgitation. In published studies, the reoperation rates ranged around 10–15% [3, 4, 10, 11, 13]. The reoperation rate in this study was acceptable. The reasons for reoperations or reinterventions in adult patients were different from those of young children. According to the reports, the reasons leading to reoperations in patients who received surgeries in childhood were most likely to be left ventricular outflow tract obstructions, mitral valve insufficiency or stenosis, residual atrial septal defects or the implantations of pacemakers [4, 11, 14]. For patients who underwent operations in adulthood, the main reasons were recurrent severe mitral valve regurgitations and implantations of permanent pacemakers [15, 16].
The mortality and reoperation rate were excellent. However, the delayed operations gave rise to additional complications. There were few PAVCs combined with tricuspid valve regurgitations in previous reports about patients underwent operations in childhood [10, 11]. In our study, there were 41(89.1%) patients had tricuspid valve regurgitations, of which 20(43.5%) were moderate or severe. 22(47.8%) patients underwent tricuspid repair in PAVC repair surgery simultaneously. The follow-up outcomes showed there were only one patient still having moderate regurgitation and none had severe regurgitation any longer. Tricuspid valvuloplasty is very effective in adult PAVSD patients.
According to the result, the mean diastolic diameter of left atriums, right atriums and right ventricles obviously increased, while the mean diastolic diameter of left ventricles stayed normal. Patients’ preoperative NYHA classes decreased significantly to class II(24, 52.6%), class III(16, 34.8%) and class IV(1, 2.2%)(P < 0.001, tested by Pearson’s chi-squared test). Arrythmia especially atrial fibrillations were common among these patients. On the other hand, there were few reports demonstrating significant atriums’ or ventricles’ dilation in young partial AVSD patients, and the arrythmias were relatively infrequent [10, 11]. Delayed operations seemed to induce additional preoperative complications in patients. Post operation, according to most recent result, the condition of tricuspid valve regurgitations, dilated right atriums and right ventricles and arrythmia were all improved. However, dilation of left atriums saw no change, which had influence on heart function . The reason and mechanism behind and the long-term effect of dilated left atriums on postoperative adult PAVC patients need further studies.