Transcatheter sinus venosus defect (SVD) closure carries a procedural success rate of 97%, according to a new study, which noted that the use of long, premounted, covered stents simplified the procedure. The investigation, which was published Monday online, also attributes the high success rate to recent technical modifications, which decreased procedural complexity and invasiveness, and increased patient inclusion without compromising safety. Other deciding factors include pulmonary vein protection and including patients with high-draining additional veins, which researchers said broadened the scope of this procedure. On reducing the procedure’s complexity, they said: “Intubation anesthesia and continuous TEE [transesophageal echocardiogram] monitoring was replaced by a brief conscious TEE imaging in limited patients with residual shunt on pulmonary venography. “Pressure measurements and angiogram from the RUPV [right upper pulmonary vein] catheter provided similar information,” the paper’s authors continued. “Avoiding intubation benefitted high-risk patients with morbid obesity and pulmonary arterial hypertension.” Main study findings Led by Pramod Sagar, MD, from the Institute of Cardiovascular Diseases, Madras Medical Mission in Chennai, India, the team enrolled 100 patients who underwent SVD closure after balloon interrogation. Among 57 patients balloon interrogated in the first 5 years, 70% underwent transcatheter closure, with two failures with RUPV occlusion causing the exclusions. Inclusions improved to 94% among the subsequent 65 balloon interrogations when RUPV protection was implemented, with one failure. The research team added that stent embolization caused the three failures warranting surgery. Recent modifications included limited TEE without anesthesia, avoiding venovenous circuit, among others resulted in no deaths. “The feasibility of transcatheter closure improved to 94% after pulmonary vein protection and including patients with additional high-draining veins,” added the paper’s authors, which was published in the June 4 issue of the Journal of the American College of Cardiology. “This rate was higher than in previous reports. Trans-septal pulmonary vein protection was safe without complications in our experience. “Protective balloon in RUPV inflated at 10 to 12 atm prevented its narrowing by the covered stent expanded at 3 to 4 atm,” they added. “Additional high draining veins that were not amenable for a redirection were left to drain into the SVC [superior vena cava] during surgery.” Updating efforts Ryan Callahan, MD, and Matthew J. Gillespie, MD, from the Children’s Hospital of Philadelphia, and University of Pennsylvania Perelman School of Medicine in Philadelphia, applauded the team for consistently updating their technical modifications and reporting complications of transcatheter SVD closure over the past decade. “Their work has led to this comprehensive summary, which boasts the largest sample size and longest follow-up to date,” they said in an accompanying editorial comment. “Most impressive is the increase in patient eligibility through modifications in balloon interrogation and pulmonary vein protection and their limited use of general anesthesia.” However, the experts described the overall eligibility as “ill defined.” The experts pointed out that the descriptions of caudal extension and large high-draining additional vein were not fully delineated and that the number of patients fulfilling those criteria were not presented. Need for bailout stents Other issues with the study methodology included the need for bailout stents and the presence of residual shunts, most of which were thought to be clinically insignificant. “This again speaks to the variability of the anatomy and the balance between adequately securing the stent in the compliant nonstenotic SVC while simultaneously attempting to cover the defect in the right atrium, possibly with stents shorter than desired,” the two commenters said. “Although the use of longer stents may prevent these issues in most patients, there will never be one size that fits all.” Also noteworthy were the newly reported patients with stent thrombus and the issues related to temporary SVC occlusion. Callahan and Gillespie said further investigation was needed to determine who was at highest risk, with special attention to patients with bilateral SVCs. “Balloon interrogation, at this point, is an integral procedural component,” they added. “Efforts should be made to recognize patients intolerant to temporary SVC occlusion and identify strategies to limit inflation time. The experts concluded by stating that as experience continues to flourish, the hope is to have SVD phenotype-specific devices, either in currently available stents or in novel lesion-specific devices, which continue to simplify the procedure and optimize patient outcomes. Study methodology The single-center study enrolled a total of 100 patients with a median age of 35 years (interquartile range: 4-69 years), of whom nine patients were ≤12 years old. Forty-nine (49%) of these patients were female. Patients were included if balloon interrogation of the cavoatrial junction confirmed closure of the SVD and redirected the RUPV to the left atrium. These patients were monitored to summarize the procedural modifications over 8 years. TEE on follow-up was done to identify residual shunt, RUPV flows and stent thrombosis. The median follow-up duration was 19 months, and the longest follow-up was 90 months. Fifty-six cases completed 1 year of follow-up. Sources: Sagar P, Sivakumar K, Thejaswi P, et al. Transcatheter Covered Stent Exclusion of Superior Sinus Venosus Defects. J Am Coll Cardiol. 2023;83:2179–2192. Callahan R, Gillespie MJ. Transcatheter Superior Sinus Venosus Defect Closure: Experience Increases Patient Eligibility. J Am Coll Cardiol. 2023;83:2193–2195. Image Credit: Bipul Kumar – stock.adobe.com