Toward predictive modeling of catheter-based pulmonary valve replacement into native right ventricular outflow tracts.

2018

2018 Nov 15

1522-726X

<p><strong>BACKGROUND: </strong>Pulmonary insufficiency is a consequence of transannular patch repair in Tetralogy of Fallot (ToF) leading to late morbidity and mortality. Transcatheter native outflow tract pulmonary valve replacement has become a reality. However, predicting a secure, atraumatic implantation of a catheter-based device remains a significant challenge due to the complex and dynamic nature of the right ventricular outflow tract (RVOT). We sought to quantify the differences in compression and volume for actual implants, and those predicted by pre-implant modeling.</p>

<p><strong>METHODS: </strong>We used custom software to interactively place virtual transcatheter pulmonary valves (TPVs) into RVOT models created from pre-implant and post Harmony valve implant CT scans of 5 ovine surgical models of TOF to quantify and visualize device volume and compression.</p>

<p><strong>RESULTS: </strong>Virtual device placement visually mimicked actual device placement and allowed for quantification of device volume and radius. On average, simulated proximal and distal device volumes and compression did not vary statistically throughout the cardiac cycle (P = 0.11) but assessment was limited by small sample size. In comparison to actual implants, there was no significant pairwise difference in the proximal third of the device (P &gt; 0.80), but the simulated distal device volume was significantly underestimated relative to actual device implant volume (P = 0.06).</p>

<p><strong>CONCLUSIONS: </strong>This study demonstrates that pre-implant modeling which assumes a rigid vessel wall may not accurately predict the degree of distal RVOT expansion following actual device placement. We suggest the potential for virtual modeling of TPVR to be a useful adjunct to procedural planning, but further development is needed.</p>

10.1002/ccd.27962

Catheter Cardiovasc Interv

30444053

Implantation of the Medtronic Harmony Transcatheter Pulmonary Valve Improves Right Ventricular Size and Function in an Ovine Model of Postoperative Chronic Pulmonary Insufficiency.

2016

2016 Oct

1941-7632

<p><strong>BACKGROUND: </strong>Pulmonary insufficiency is the nexus of late morbidity and mortality after transannular patch repair of tetralogy of Fallot. This study aimed to establish the feasibility of implantation of the novel Medtronic Harmony transcatheter pulmonary valve (hTPV) and to assess its effect on pulmonary insufficiency and ventricular function in an ovine model of chronic postoperative pulmonary insufficiency.</p>

<p><strong>METHODS AND RESULTS: </strong>Thirteen sheep underwent baseline cardiac magnetic resonance imaging, surgical pulmonary valvectomy, and transannular patch repair. One month after transannular patch repair, the hTPV was implanted, followed by serial magnetic resonance imaging and computed tomography imaging at 1, 5, and 8 month(s). hTPV implantation was successful in 11 animals (85%). There were 2 procedural deaths related to ventricular fibrillation. Seven animals survived the entire follow-up protocol, 5 with functioning hTPV devices. Two animals had occlusion of hTPV with aneurysm of main pulmonary artery. A strong decline in pulmonary regurgitant fraction was observed after hTPV implantation (40.5% versus 8.3%; P=0.011). Right ventricular end diastolic volume increased by 49.4% after transannular patch repair (62.3-93.1 mL/m(2); P=0.028) but was reversed to baseline values after hTPV implantation (to 65.1 mL/m(2) at 8 months, P=0.045). Both right ventricular ejection fraction and left ventricular ejection fraction were preserved after hTPV implantation.</p>

<p><strong>CONCLUSIONS: </strong>hTPV implantation is feasible, significantly reduces pulmonary regurgitant fraction, facilitates right ventricular volume improvements, and preserves biventricular function in an ovine model of chronic pulmonary insufficiency. This percutaneous strategy could potentially offer an alternative for standard surgical pulmonary valve replacement in dilated right ventricular outflow tracts, permitting lower risk, nonsurgical pulmonary valve replacement in previously prohibitive anatomies.</p>

10.1161/CIRCINTERVENTIONS.116.003920

Circ Cardiovasc Interv

27662847