Intramural Ventricular Septal Defect Is a Distinct Clinical Entity Associated With Postoperative Morbidity in Children After Repair of Conotruncal Anomalies

Abstract

Background Intramural ventricular septal defects (VSDs) are interventricular communications through right ventricular free wall trabeculations that can occur after repair of conotruncal anomalies. We assessed the prevalence of residual intramural VSDs and their effect on postoperative course. Methods and Results Children who underwent biventricular repair of a conotruncal anomaly from 1/1/06 to 6/30/13 and had a post-operative transthoracic echocardiogram were included. Images were reviewed for residual intramural or non-intramural VSDs. The primary outcome was a composite of mortality, extracorporeal membrane oxygenation (ECMO) use, and need for subsequent catheter or surgical VSD closure. The secondary outcome was post-operative hospital length of stay (PLOS). A residual VSD was present in 256 of the 442 subjects (58%), of which 231 (90%) were <2mm in size. Forty-nine (11%) had intramural VSDs and 207 (47%) had non-intramural VSDs. Patients with intramural VSDs were more likely to reach the primary composite outcome compared to those with non-intramural VSDs or no residual VSD (14/49 [29%] vs 15/207 [7%] vs 6/186 [3%], p<0.0001). In addition, those with intramural VSDs had longer PLOS compared to those with non-intramural VSDs or no residual VSD (20 days [IQR 11-42] vs 7 days [5-14] vs 6 [4-11], p=0.0001). These associations remained significant after adjusting for known risk factors for poor outcomes, including residual VSD size and operative complexity. Conclusions Among residual VSDs after repair of conotruncal anomalies, intramural VSDs are uniquely associated with postoperative morbidity, mortality, and longer PLOS. It is important to recognize intramural VSDs in the postoperative period.

Intramural Ventricular Septal Defect

“…Children with hemodynamically significant intramural VSDs are reported to have a substantially higher rate of postoperative morbidity, mortality, and hospital stays. Intramural VSDs are also reported to be larger than other residual VSDs that might lead to increased clinical sequels [1,2]. The prevalence, risk factors and outcomes of these unusual residual defects are not well defined in the literature.…”

“…In the study by Patel et al, an 11% of studied population were found to have intramural VSDs after repair of conotruncal abnormalities accounting for 19% of residual VSDs. Most of the affected patients had undergone total correction for tetralogy of Fallot as it is the most common type of conotruncal abnormality but a higher incidence in the more complex conotruncal pathologies should be expected [1]. Diagnosis could be far more challenging than other types of residual VSDs.…”

“…Deep transgastric views with smooth short axis rotations may better envision the defects during transesophageal echocardiography [4,5]. Even in intramural VSDs that seem hemodynamically insignificant early after operation, close follow up with transthoracic echocardiography is recommended, as there is a possibility for gradual enlargement and increase in the ventricular level blood shunting, with a common cause being consistent regression of RV hypertrophy following corrective surgery for RV outflow tract stenosis [1][2][3]. There are no large-scale studies on preferred method of repair of hemodynamically significant intramural VSDs.…”

“…If the patch is inserted somewhere within the hyper trabeculated RV wall far from the aortic valve, leakage of blood through the inter-trabecular recesses and the insertion site leads to left to right shunting. During repair of conotruncal abnormalities, this could happen more commonly due to characteristic multiple hypertrophied muscle bundles and course trabeculations in the right ventricle [1][2][3]. Here we present a typical case with a history of frequent surgeries and intramural VSDs.We also review the deficient existing literature in this regard.…”

Impact of anatomic characteristics and initial biventricular surgical strategy on outcomes in various forms of double-outlet right ventricle

“…Nevertheless, the IVR, with or without enlargement of VSD, carries a high risk for reoperation for VSD residual (or modification of baffle repair) ahead of DORVs or all types of conotruncal abnormalities. 17 We believe this surgical parameter requires a particularly precise surgical management (size and localization of septal resection) to avoid risks in the short term (conduction disorders, residual VSD) and long term (subaortic obstruction). In regard to reoperation for left ventricular outflow obstruction, one may conclude that an aggressive approach with almost routine VSD enlargement may decrease late left ventricular outflow obstruction.…”