Tissue Engineered Transcatheter Pulmonary Valved Stent Implantation: Current State and Future Prospect

Patients with the complex congenital heart disease (CHD) are usually associated with right ventricular outflow tract dysfunction and typically require multiple surgical interventions during their lives to relieve the right ventricular outflow tract abnormality. Transcatheter pulmonary valve replacement was used as a non-surgical, less invasive alternative treatment for right ventricular outflow tract dysfunction and has been rapidly developing over the past years. Despite the current favorable results of transcatheter pulmonary valve replacement, many patients eligible for pulmonary valve replacement are still not candidates for transcatheter pulmonary valve replacement. Therefore, one of the significant future challenges is to expand transcatheter pulmonary valve replacement to a broader patient population. This review describes the limitations and problems of existing techniques and focuses on decellularized tissue engineering for pulmonary valve stenting.

Intravascular ultrasound for peri-procedural geometric orifice area measurement during transcatheter pulmonary valve replacement

Introduction Large imaging filed intravascular ultrasound (IVUS) offering superior online tomographic perspective and visual accuracy could guide transcatheter pulmonary valve replacement (TPVR) for right ventricular outflow tract (RVOT) insufficiency. It is unknown whether geometric orifice area (GOA) measured by IVUS corresponds with effective orifice area (EOA) measure by transthoracic echocardiography (TTE) after successful TPVR. Purpose To compare minimal inner-leaflets cross-sectional area delineated in systole (min GOA) measured by IVUS versus EOA calculated = right ventricle stroke volume (measured in baseline cardiac magnetic resonance) / pulmonary valve velocity time integral (measured early post-procedure by Vivid e95). Methods After successful TPVR a 10MHz Vision PV 0.035" (60mm imaging field) IVUS catheter was slowly pulled from the distal pulmonary artery to the right ventricle with continuous imaging of RVOT. IVUS measurements included inner-valve dimension for several evenly spaced cross-sections along the entire length and perpendicular to RVOT long axis. Measured were outer-frame diameters (minimal and maximal) and its cross-sectional area, and cross-sectional area of the visual orifice (min GOA) identified exclusively at the coaptation site (Fig 1). Results There were 11 pts (median age 30 [25–36] yrs, 4 ♀, all but one with Tetralogy of Fallot) who had undergone prior corrective surgery (5 transannular patch, 2 bioprosthetic valve or 4 pulmonary homograft). Overall, 176 cross-sections were analyzed. Overall, min GOA measured 3.7±1.0cm2, and was 68%±9% of the valve-outer area (5.5±1.5cm2). It was substantially larger than calculated EOA (3.7±1.0cm2 vs 2.0±0.5cm2; p<0.001). The ratio of max/min GOA diameter was 1.11±0.11 signifying low eccentricity and was not related to EAO. Conclusions After successful balloon-expandable valve implantation to treat RVOT insufficiency, geometric orifice dimension was significantly smaller then outer valve frame dimension. Visual measure of geometric orifice area during the procedure using IVUS documented its circularity and indicated that it was larger than EOA calculated upon functional measure. FUNDunding Acknowledgement Type of funding sources: Public hospital(s). Main funding source(s): This work was supported by the research grant (2.4/VI/18) founded by the National Institute of Cardiology in Warsaw (Poland). IVUS visualization of ES3.

A Hybrid Strategy for Geometrical Reshaping of the Main Pulmonary Artery and Transcatheter Pulmonary Valve Replacement

Transcatheter pulmonary valve replacement has become an attractive alternative to surgical approach in patients with dysfunctional right ventricular outflow tract. However, in certain cases, an unfavorable anatomy might complicate optimal valve deployment and stability. Several techniques have been described to reshape the landing zone and allow proper implantation of the transcatheter valve. Among them, the hybrid approach has gained attention as an interesting method for off-pump pulmonary valve replacement in patients with dilated right ventricular outflow tract. But to date, there is no standardized method to resize and reshape the landing zone for the stented valve. Here, we describe a reproducible method based on simple geometric rules to allow adequate remodeling of the main pulmonary artery to the desired dimensions in a single attempt, followed by perventricular implantation of a Venus P-valve.

Case report: successful emergent transcatheter pulmonary valve replacement within failing pulmonary artery conduit in the setting of cardiogenic shock with extracorporeal membrane oxygenation support

Background To the best of our knowledge, this is the first reported case of transcatheter pulmonary valve replacement (TPVR) with extracorporeal membrane oxygenation (ECMO) support with successful decannulation as a bridge to recovery in a young adult with complex congenital heart disease. Case summary We describe a 24-year-old male patient with a history of D-transposition of the great arteries with ventricular septal defect status post-Rastelli repair at age three lost to follow-up and presenting with severe biventricular failure, left ventricular thrombus, and critical pulmonary conduit stenosis, deemed non-surgical and non-transplant candidate, who underwent conduit stenting and TPVR in the setting of cardiogenic shock. Upon intubation for general anaesthesia, the patient suffered from ventricular tachycardia arrest requiring cardiopulmonary resuscitation and veno-arterial ECMO. Once stabilized, conduit stenting and TPVR was performed with significant haemodynamic improvement and immediate ECMO decannulation with subsequent biventricular function improvement. Discussion In critically ill patients with complex congenital heart disease that are neither surgical nor transplant candidates, ECMO support can be used as a means of support during a transcatheter intervention to improve haemodynamics and a bridge to recovery, allowing time for future potential candidacy for surgery or transplantation as indicated. Patients with congenital heart disease need regular follow-up in specialty clinics to prevent the development of such critical illness.