Study of right ventricular outflow tract gradient in immediate postoperative period following intracardiac repair for tetralogy of Fallot

Background: Surgical repair of tetralogy of Fallot (TOF) consists of adequate ventricular septal defect closure and relief of right ventricular outflow tract (RVOT) obstruction to the greatest extent possible. The residual RVOT gradient can be due to dynamic and fixed obstruction, and high gradient is sometimes seen even after a satisfactory RVOT resection often confirmed with intraoperative TransEsophageal Echocardiogram (TEE). Aim: The present study was conducted to study the changes in RVOT residual gradient in the early postoperative period. We analyzed the change in residual gradient by invasive monitoring intraoperatively after separating from cardiopulmonary bypass (CPB) in a case of intracardiac repair (ICR) for TOF and compared the readings 24 h after extubating the patients in intensive care unit (ICU). Materials and Methods: This was an observation study done in the Department of CTVS, Advanced Cardiac Centre, PGIMER, and Chandigarh from February 2018 to March 2019. A total of thirty patients with preoperative diagnosis of TOF were included in the study. After ICR for TOF, postseparation from CPB, RVOT gradient was measured using 23G needle connected to pressure transducer and compared with RVOT gradient measured 24 h postextubating using invasive line kept intraoperatively in pulmonary artery and RVOT. Results: There was a significant decrease in residual RVOT gradient postoperatively in ICU after 24 h of extubating, in comparison to intraoperative postbypass residual RVOT gradient. Postbypass residual RVOT gradient was 11.33 ± 1.39 that decreased to 7.81 ± 1.29 24 h after extubating (P < 0.05). Patients in whom pulmonary valve was preserved had greater postbypass residual RVOT gradient (12.44 ± 1.13) than patients with transannular patch (10.5 ± 0.90). However, both decreased after 24 h of extubating (9 ± 0.7 and 6.9 ± 0.8, respectively). Conclusion: Once satisfactory RVOT resection for fixed obstruction is done and is confirmed using TEE, the residual gradient, if marginally high, can be ignored as residual gradient significantly decreases after extubation and hemodynamic improvement is seen in postoperative period.