Novel percutaneous technique for creation of porcine model of tricuspid regurgitation via two routes

Abstract

Objective: To develop an experimental porcine model of tricuspid regurgitation using two induction routes: the inferior vena cava and superior vena cava.

Methods: Tricuspid regurgitation was generated using the loop wire cutting method. The tricuspid regurgitation jet direction was controlled by accessing the valve through the inferior (n = 7) or superior (n = 6) vena cava. The occurrence, direction, and progression of tricuspid regurgitation were assessed postoperatively, and echocardiography was performed at 4 to 6 weeks. Right heart dilatation was assessed using computed tomography after 6 weeks.

Results: Moderate to severe or torrential tricuspid regurgitation occurred immediately after the procedure in 12 of 13 animals. The jet was directed toward the septum in five of seven animals in the inferior vena cava group and toward the posterolateral side in four of six animals in the superior vena cava group. The dimensions of the right heart (right atrium, ventricle, and tricuspid valve annulus) were significantly enlarged at the 4- to 6-week follow-up echocardiographic examination and confirmed to be enlarged by computed tomography, independent of the route used.

Conclusion: The loop wire cutting method successfully induced a disease model of tricuspid regurgitation while controlling the regurgitation jet direction via two procedural routes.

Keywords: Animal disease model; functional tricuspid regurgitation; loop wire cutting method; regurgitation jet; survival model; tricuspid valve disease.

Figure 1.

Schematic illustration of the two routes and the damaged tricuspid valve structure. (a, b) IVC route. (a) A wire-guided catheter and a snare are introduced through the IVC and placed along the narrow space among the tricuspid valve chordae tendineae between the RA and RV. A loop cutter is then formed to inflict damage to the tricuspid valve structure. (b) Pulling the loop through the IVC causes damage to the septal side of the tricuspid valve structure. (c, d) SVC route. (c) A wire-guided catheter and a snare are introduced through the SVC and placed along the narrow space among the tricuspid valve chordae tendineae near the pulmonary artery. A loop cutter is then formed to inflict damage to the tricuspid valve structure and (d) pulling the loop through the SVC causes damage on the posterolateral side. IVC, inferior vena cava; RA, right atrium; RV, right ventricle; SVC, superior vena cava.

Figure 2.

Tricuspid regurgitation induction and specimen of ruptured tricuspid valve structure. The guidewire and snare catheter form a loop around the tricuspid valve structure following entry through (a) the right femoral vein in the inferior vena cava route and (b) the right internal jugular vein in the superior vena cava route and (c) chordae tendineae and papillary muscles are ruptured by pulling the loop and released from the sheath.

Figure 3.

Echocardiographic assessment at 4-week follow-up and dimensions of right heart. (a) Tricuspid regurgitation on the septal side through the TV (white arrow) after performing the procedure through the inferior vena cava. (b) Tricuspid regurgitation from the posterolateral side was observed after performing the procedure through the superior vena cava and (c) the modified four-chamber view with the swine in the supine position. The dimensions of the RA, Mid-RV, and TV annulus were measured as shown (dotted arrows). LA, left atrium; LV, left ventricle; RA, right atrium; RV, right ventricle; TV, tricuspid valve; Mid-RV, mid-portion of right ventricle.

Figure 4.

Multiplanar reformatted computed tomography 6 weeks after procedure. The RV/LV (R/L) ratio was (a) 1.4 in Pig No. 7 from the superior vena cava group with torrential tricuspid regurgitation following chordae rupture and (b) 1.3 in Pig No. 12 from the inferior vena cava group with torrential tricuspid regurgitation following chordae rupture. L, left; LA, left atrium; LV, left ventricle; R, right; RA, right atrium; RV, right ventricle.