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18855 Lora Ronco.mp4 (269.06 MB)

Transcatheter Mitral Valve Replacement with the TMVR Tendyne Transapical System

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posted on 2023-06-26, 16:26 authored by Lorenzo Lora Ronco

This video presents a transcatheter transapical mitral valve replacement with the implantation of the Abbott Tendyne system.

The implantation team was composed of both cardiac surgeons and interventional cardiologists. The valve was implanted under general anesthesia and the procedure was guided by transesophageal 3D echocardiogram and fluoroscopy. The Tendyne system is a transcatheter pericardial valve that is composed of an intra-annular nitinol stent and an atrial skirt, which both allow the valve to seal. A tether tendon is also fixed outside the left ventricular apex by a pad, thus allowing for complete valve fixation.

The Patient

The patient is an eighty-four-year-old man with common cardiovascular risk factor. He suffered from colon and prostate cancer, with negative oncologic follow-up. He underwent coronary artery bypass grafting in 2001. In recent years, he progressively developed ischemic cardiomyopathy with low left ventricular (LV) ejection fraction and severe functional mitral regurgitation. He was admitted for minimal effort dyspnea and a NYHA class III under optimal medical therapy.

At the preoperative echocardiography, the patient presented with moderate LV dysfunction with an ejection fraction nearing 40 percent due to inferior akinesia, a severe left atrium (LA) enlargement, and a severe functional mitral regurgitation (MR) due to bileaflets tethering and severe regurgitation all along the coaptation line. Moderate pulmonary hypertension was detected, resulting in right ventricular (RV) dilatation and moderate to severe tricuspid regurgitation (TR).

CT scan reconstruction was mandatory for procedural planning and prosthesis choice. First, native mitral valve (MV) annulus was assessed, including intercommissural diameter, septolateral diameter, and annular perimeter. Prosthesis dimension was assessed according to these measurements in order to achieve a 4–10 percent oversizing.

Neo-LVOT assessment is the most crucial part of procedural planning. In TMVR, the anterior MV leaflet is fixed in diastolic position toward the IV septum, thus determining a sort of LVOT tunnel that, in certain anatomical conditions, can result in subaortic stenosis. 

The chosen prosthesis was virtually simulated in CT scan reconstruction and neo-LVOT was calculated in diastole and systole. As in the present case, a neo-LVOT greater than 250 mm2 is accepted for a safe implantation. Next, the puncture site on the LV apex was carefully assessed. The insertion site, marked by a green dot, can be different from the true LV apex, marked by a red dot, because surgeons want to achieve an implant trajectory which is both free from the MV subvalvular apparatus and perpendicular to the MV plane.

The Surgery

First, a mini thoracotomy was performed in the left anterior chest, according to CT scan planning and four chamber view at transthoracic echo. The pleural cavity was progressively entered and a soft tissue retractor—or rib spreader—was inserted. Pleuropericardial fat was removed in order to gain a better access to the LV apex, and a finger poke test was applied in order to confirm the correct position on cardiac apex. Using transesophageal echo, X-plane imaging, and the finger-poke test allowed surgeons to ascertain that the puncture site was centered on the mitral plane and the trajectory was free from subvalvular apparatus. 

The pericardium was then opened and suspended; adherences from previous surgery were gently dissected. The puncture site was further confirmed by finger poking and marked with blue ink. Two concentric 3-0 Prolene purse-string sutures, reinforced by Teflon pledgets, were performed around the puncture site to assure LV apex hemostasis. The LV apex was punctured with an angiographic needle and a starter 0.035 guidewire was advanced. A 6 Fr sheath was then inserted over the wire. A Swan-Ganz catheter was inserted and the guide wire was advanced in the left atrium by means of tip balloon inflation. Under echo guidance, the balloon was then advanced and retrieved over the wire 3-4 times using the lollipop maneuver in order to confirm that the implantation trajectory was free from papillary muscle or mitral valve chordae. A 6 Fr sheath was then removed and the 36 Fr Tendyne delivery system was advanced through the LV apex over the wire. Once the tip of the sheath was confirmed to be 1 cm over the mitral valve plane, the wire was retrieved and the valve was advanced through the delivery by turning the appropriate knob. Once the valve was approaching the tip of the delivery, echocardiogram view was switched into the 3D en face projection. The opening of the valve continued, assuring that the straight anterior part of the atrial cuff was aligned to the aortomitral continuity. 

Once alignment was completed, echocardiogram view was switched to X-plane projection. Intra-annular sitting of the prosthesis was checked on both planes of the mitral valve. Once the prosthesis was correctly seated into the MV annulus, the delivery system was retrieved and exchanged with the pad tensioning system. The fixing pad was advanced up to the LV and tendon tension was locked at the apical level. LV apex hemostasis was achieved by means of purse string tightening. Final tensioning of the prosthesis was completed under echocardiogram guidance in order to achieve perfect intra-annular seating without any paravalvular leakage or LVOT obstruction. Once the apical pad was fixed, the tendon was cut 5 cm away from the pad. A chest drainage was placed into the left pleural cavity and the chest was closed in a standard fashion.

After valve deployment, a moderate afterload mismatch was observed, but it was promptly solved with a moderate inotropic support. The ICU postoperative course was uneventful, and the patient was promptly extubated. The following postoperative course was uneventful.

A pre-discharge echocardiography showed good prosthesis sitting without any rocking or periventricular leukomalacia. The mean antegrade MV gradient was 4 mmHg and no residual MR was detected. Pulmonary artery pressure as well as TR showed moderate improvement.

Reference(s)

1. Transcatheter Mitral Valve Replacement. Hensey et al. - JACC: Cardiovascular Interventions - 2021

2. Transcatheter Mitral Valve Replacement for Patients With Symptomatic Mitral Regurgitation: A Global Feasibility Trial

3. Muller DWM;Farivar RS;Jansz P;Bae R;Walters D;Clarke A;Grayburn PA;Stoler RC;Dahle G;Rein KA;Shaw M;Scalia GM;Guerrero M;Pearson P;Kapadia S;Gillinov M;Pichard A;Corso P;Popma J;Chuang M;Blanke P;Leipsic J;Sorajja P

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