Discussion
SVC stenosis in pediatric population is usually because of postoperative sequelae to prior cardiac surgery.1 “True” Congenital SVC stenosis is an extremely rare entity. To the best of our knowledge, co-existence of this anomaly with obstructed TAPVC, has never been reported. We believe the etiology in our case was transmural fibrosis emanating from the draining ostium of common chamber, involving SVC circumferentially.
Symptomatic SVC obstruction may increase venous pressure, depicted as SVC syndrome, but the degree and severity of symptoms depend on the extent and rate of progression of narrowing.2 In our case disproportionate edema in the SVC distribution was absent, indicating gradual development of narrowing in-utero. Also massive dilation of proximal SVC, could have acted as a reservoir. In the era when a TTE is performed as a standalone test, subtle findings can be overlooked.4 Disproportionate edema or dilated veins in the SVC distribution are critical physical findings that should prompt focused evaluation for this etiology. Focused TTE and CT can readily establish the diagnosis in these sick infants.
Neonates and infants with obstructed TAPVC can present with severe cyanosis, pulmonary hypertension, and low cardiac output, requiring emergency surgical intervention.5 In our patient, the drainage of CC was almost atretic, but the lungs were not congested. Coexisting critical SVC stenosis can limit the amount of blood going towards the common chamber. We are not sure, whether coexisting SVC stenosis can decrease the severity of pulmonary venous hypertension, by limiting the amount of blood flow into the obstructed common chamber.
Management of SVC obstruction needs to be tailored according to the etiology and coexisting malformations. For isolated SVC stenosis, stenting is becoming the modality of choice compared to surgery due to its reduced post-procedure morbidity and faster recovery time.2 Intravascular stent placement is safe and effective even in term infants.3 However lack of growth potential and recurrence of sympyoms, mandates reinterventions. Considering the small vessel size as well the growth potential in pediatric population, surgical repair with patch augmentation is ideal, especially in the setting of an associated CHD which needs surgical correction. In our patient, associated obstructed supracardiac TAPVC mandated surgical intervention for SVC stenosis. We resorted to pericardial patch augmentation of SVC along with anastomosis of common chamber to the posterior wall of LA.
The hemodynamic effect produced by a combination of systemic venous hypertension and pulmonary venous hypertension can be extremely lethal especially in infants. Clinical condition should prompt focused evaluation by TTE and CECT. We believe surgical repair with a pericardial patch, can be curative for SVC stenosis in pediatric population, by providing growth potential.