A retrospective study was conducted in March 2019 after taking the clearance from the Institutional Review and Ethics committee (approval letter number 4240/19). The medical records from December 2004 to December 2017 were reviewed retrospectively. There were 27 patients who were admitted with a diagnosis of RSOV for trans-catheter closure of the defect. Of these trans-catheter device closure was performed on 24 patients and 3 patients were referred for surgical closure due to associated cardiac lesions requiring surgery (one patient had infundibular pulmonary stenosis, the second had moderate sized sub-aortic ventricular septal defect not amenable to trans-catheter device closure and the third patient had a large PDA which could not be closed with a device). After the routine blood investigations, electrocardiography, chest radiography, transthoracic and transesophageal echocardiography, the patients were admitted for trans-catheter device closure once written consent was obtained.

The data regarding patient’s demographic details, chief symptoms at presentation, electrocardiography reports, echocardiographic details and details about follow-up were obtained from the medical records. Procedural details were collected from the medical records and by reviewing the angiographic images.

All continuous variables are expressed as mean values and standard deviation or median with range as appropriate, and discrete variables are presented as percentages.

There were 24 patients who underwent trans-catheter device closure of RSOV [Table/Fig-1]. There were 18 males (75%). The median age of the patients was 34.5 years. Most of the patients were in NYHA class II (n=19), 4 patients were in NYHA class III/IV (in heart failure) and one patient was in NYHA class I. The most common symptom was dyspnea which was found in 20 patients (83.3%) [Table/Fig-2]. The mean diameter of the defect as measured by echocardiogram prior to the procedure was 6.3±1.7 mm. In 17 (71%) patients the RSOV was from the right coronary cusp and in 7 (29%) patients it was from the non-coronary cusp. In majority the RSOV was draining into the right ventricle in 13 (54.1%) patients [Table/Fig-3]. The median hospital stay was 3 days.

[Table/Fig-1]:

This depicts the total number of patients in whom RSOV device closure was attempted.

The mean diameter of the defect according to the angiographic measurement was 6.3±1.7 mm [Table/Fig-3]. An arterio-venous guide wire circuit was created in all patients [Table/Fig-4] except one in whom the RSOV was draining into the left ventricle and hence an arterio-arterial guidewire circuit had to be established. In 21 patients Heart and CeraLifetech PDA occluder (both ShenZhenLifetech Scientific Inc., China) sizes ranging from 10 to 18 mm were used, in 2 patients Cardi-O-Fix PDAOccluder (Starway Medical Corporation, China), sizes of 12 and 14 mm were used and in one patient AmplatzerTM Vascular Plug II of size 8 mm (AGA Medical Corporation, Golden Valley, Minnesota, USA) was used, as shown in [Table/Fig-5]. The median fluoroscopic time was 13.5 minutes and the mean procedure time was 62.8±17.8 minutes. Access site haemostasis was achieved by manual compression in all cases.

[Table/Fig-4]:

AV loop.

a. Aortogram in LAO view

b. Aortogram in RAO view

(Blue arrow indicates the defect in both the views)

c. Establishing Arteriovenous (AV) guidewire circuit (Orange arrow indicates the AV loop)

d. RAO view showing the device positioned across the defect

e. RAO view showing final aortogram and no residual flow across the shunt

(Red arrow shows the device after successful deployment)

[Table/Fig-5]:

a) It shows the devices used (all except one was PDA occluder). b) Various PDA occluder device sizes used.

Post procedure there was no increase in aortic regurgitation in any of the patients-five patients (20.8%) had trivial shunt at the end of the device closure angiographically, 1 patient had intra-procedure rupture of the aneurysmal sac during device deployment resulting in mortality. One patient had significant shunt at the end of the procedure which persisted beyond 1 week and was subsequently referred for surgical closure. A third patient had to be referred for surgery because of device embolization into branch pulmonary artery on the left side, detected by echo on day 2 post procedure. There were no access site complications, stroke, or coronary occlusions due to device impingement in any of the patients. One patient developed pulmonary oedema post procedure which was successfully managed medically.

The median follow-up was after 8 months. All patients except one, had no residual shunt as assessed by transthoracic echocardiogram at 6 months follow-up. The one patient with a residual shunt had a gradient of 96 mm Hg across the shunt, suggesting that the shunt was restrictive. All patients who successfully underwent trans-catheter device closure were in NYHA class I at follow-up and asymptomatic. All patients had normal LV systolic function and normal LV dimensions at follow-up.

In the present series, successful device deployment without immediate or intermediate complications was achieved in 21 of the 24 patients (87.5%) in whom the procedure was attempted. All but one patient had complete occlusion of the defect and no residual shunt across the defect at 6 months follow-up. The rate of successful closure of RSOV in the present series was similar compared to data from other studies which are approximately 75-85% [4-7].

RSOVs are more common in Asian males and various reports have quoted a male: female ratio ranging from 1.7:1 to 4:1 [8,9]. In the present series the male: female ratio was 3:1. Clinical presentation of RSOVs can be myriad-ranging from asymptomatic individuals to patients with overt heart failure. In the present series the most common symptom was dyspnea followed by palpitations. All patients were admitted for cardiac catheterization study with intent to perform a device closure. However, in 3 patients the procedure was not performed due to reasons stated earlier and they were referred for surgical closure.

There are multiple variables that affect the probability of a successful device closure including the size and morphology of the defect, the proximity of defect to the respective coronary arteries, the degree of aortic valve incompetence, vascular accessibility and the choice of device used for the procedure [7]. In the present series an arteriovenous guidewire circuit was established in all patients but one in whom the defect was draining into the left ventricle and consequently an arterio-arterial guidewire circuit was established. PDA occluders were used in 23 patients (95.8%) with sizes ranging from 12/10 mm to 18/16 mm and in one patient an Amplatzer Vascular plug II-8 mm size was used. PDA occluders are cost effective and also offer the advantage of being available across a wide range of sizes which made us choose them more often over the other available devices. In the study by Mahimarangaiah J et al., PDA devices were used in 70% of the patients [7].

There are a number of complications that have been reported after trans-catheter device closure of RSOV. Some of them include device slippage and embolization requiring surgical retrieval, aortic valve regurgitation, coronary occlusion due to device impingement, right ventricular outflow tract obstruction due to protrusion of the device, device infection, haemolysis, and Left Ventricular (LV) systolic dysfunction post procedure [4-7]. The patient with pulmonary oedema post procedure, secondary to LV systolic dysfunction, had normal LV systolic function at 3 month follow-up.

This was a single center retrospective analysis and the sample size is relatively small. Given that the disease is uncommon, we have tried to analyse data of last 13 years. Considering that the study was done in a large tertiary care referral centre, an inherent referral bias cannot be excluded. Follow-up echocardiogram data, though not available for all patients at 6 months post procedure, was available at varying time periods during the course of their follow-up.

From the results of the data we can conclude that trans-catheter device closure of RSOVs is a safe, feasible and effective modality of definitive treatment with favourable short and intermediate outcomes in carefully selected patients. Hence the procedure provides an attractive alternative to surgical closure, thereby avoiding the inherent morbidity of sternotomy and risks of cardiopulmonary bypass.