PAPVC is a rare congenital anomaly with a prevalence in the adult population of 0.1 and 0.31% when detected by MDCT and magnetic resonance imaging, respectively [1, 2]. In the adult population, PAPVCs originating from the pulmonary lobes are distributed in the following order of frequency: left upper lobe in 47%, right upper lobe in 38%, right lower lobe in 13%, and left lower lobe in 2% of cases; PAPVC originating from the right upper lobe has a propensity to be moderately associated with sinus venous ASD [1]. Isolated PAPVC to the RA can occur in approximately 5% of the adult and pediatric population with PAPVC to the right side of the heart, as reported by Gustafson et al. [3]. Isolated PAPVC to the RA in adults was absent in a retrospective review, as reported by Majdalany et al. [4]. TTE may not always detect PAPVC due to its limited acoustic window. However, TEE might be a valuable adjunct in terms of the accurate delineation of congenital malformations, with the exclusion of difficulty in identifying left PAPVC. MDCT has been an effective imaging modality that is able to provide reliable information for confirming the diagnosis and making an efficient surgical plan with regards to complex pulmonary venous anatomy [5].
According to the 2015 European Society of Cardiology and the European Respiratory Society guidelines for the diagnosis and treatment of pulmonary hypertension, surgery may be considered in patients with prevalent systemic-to-pulmonary shunting. The correction of congenital heart disease is recommended if PVR is less than 2.3 Wood Units but not recommended if the PVR is more than 4.6 Wood Units [6]. The 2018 American Heart Association and American College of Cardiology guidelines for the management of adults with congenital heart disease state that surgical repair is recommended for patients with PAPVC under certain conditions, which involved a Qp/Qs of more than 1.5, a Rp/Rs of less than one third, and a Pp/Ps of less than 0.5 [7]. Based on the criteria for shunt closure and clinical presentation, surgical intervention was deemed appropriate in the present patient. In patients with pulmonary artery hypertension associated with congenital heart disease which include Eisenmenger syndrome and high surgical risks due to multiple comorbidities, surgery is contraindicated. In this situation, medical treatment with pulmonary artery vasodilator therapies had been proposed, as it has been suggested that the use of Bosentan, phosphodiesterase inhibitors, and intravenous epoprostenol shows favorable functional and hemodynamic improvements [6]. Dimopoulos et al. suggests that the “treat-and-repair” concept, which combines advanced pulmonary artery vasodilator therapies with surgical repair of the defect, may be considered as an alternative approach in highly selected patients, but available data is still limited [8]. In the case that a patient is refractory to medical treatment, heart-lung or lung translation with heart surgery may be the only curative option.
If the anomalous pulmonary veins are connected to the RA only, the blood stream of the anomalous pulmonary veins can be diverted through the ASD and into the LA with the intra-atrial baffle, with less likelihood of rhythm disturbances. Given that the intact atrial septum was halfway between the right and left pulmonary venous orifices, and the right anomalous pulmonary veins maintained their normal anatomical positional relationship with the adjacent structures in this patient, an extensive baffle was necessary to reroute from the orifices of the right pulmonary veins to the surgically created ASD. Since the pressure in the newly formed LA was predicted to increase postoperatively, it was important to choose an appropriate size and design for the intra-atrial baffle. A convex bowing of the newly formed inter-atrial septum towards the RA, particularly when its size is large, may result in stenosis or obstruction of the SVC or IVC. Regarding the intra-atrial baffle, a polytetrafluoroethylene patch or untreated autologous pericardial patch are generally used [9]. However, we have adopted the repositioning of the flap of the interatrial septum so as to take advantage of the antithrombogenicity, ensuring a non-redundant baffle and avoiding potential baffle shrinkage, without removing a portion of the atrial septum or using other types of intra-atrial patches. In the present case, the length of the atrial flap was shorter than the distance between the right upper pulmonary vein and right lower pulmonary vein orifices. In order to maintain the strength of the suture, minimize the risk of tissue disruption, and complete the baffle with the interatrial septum flap alone, the flap was reinforced with suture plication and the enlarged RA was mobilized carefully in the circumference of the intracardiac anastomotic site. It was thought to be of the utmost importance that the endocardial layer between the LA and the RA was reconstructed while maintaining an extroverted configuration to prevent thrombus formation of the excised end of the atrial septum. Moreover, this additional manipulation plays an important role in allowing a shorter and straightforward pathway between the orifice of right lower anomalous pulmonary vein and the excised atrial septum. This careful placement of the intended suture bites would attribute to the relief of unbalanced turbulent blood flow into the LA during the diversion of the anomalous pulmonary venous connection.
The selection of the flap from the interatrial septum as an intra-atrial baffle, redirected from the orifices of right anomalous pulmonary veins to the surgically created ASD, could be considered as an effective alternative for patients undergoing surgical repair in an isolated PAPVC to the RA. The present case highlights the importance of high suspicion and accurate diagnosis of PAPVC in adult patients who remain undiagnosed. Additionally, the early detection of PAPVC undoubtedly would lead to the subsequent surgical treatment as a conceivable therapeutic option.