Combined endoscopic and transcatheter treatment of native mitral stenosis

INTRODUCTION

Fully endoscopic mitral valve repair surgery and transcatheter mitral valve replacement are two different treatment strategies for the management of mitral valve disease. We present a case where these two strategies are combined and supplement each other for the treatment of native mitral valve stenosis.

MATERIALS AND METHODS

An 86-year old lady was admitted with recurrent episodes of breathlessness. She had a history of chronic kidney disease and previous aortic valve replacement with bioprosthesis combined with a single coronary artery bypass vein graft.

Transthoracic echocardiography revealed severe mitral stenosis (mean gradient: 16 mmHg, mitral valve area: 0.7 cm²). There was moderate mitral insufficiency, mild biventricular dysfunction and evidence of pulmonary hypertension. The mitral valve annulus and subvalvular apparatus appeared to be severely calcified. Coronary angiography showed patent vein graft. Taking into consideration our unit's experience in reoperative endoscopic mitral valve surgery [1] as well as the patient's clinical condition, age and frailty, a decision was reached for her disease to be treated in a less invasive setting.

The initial valve assessment was performed using non-rib spreading, port-access endoscopic technique using a 4-cm mini-thoracotomy on the fourth intercostal space and a 5-mm endoscope. Cardiopulmonary bypass was established through the right femoral vessels. The heart was isolated and cardioplegia was delivered by using an intra-aortic occlusion device (IntraClude, Edwards Lifesciences, Irvine, CA, USA). The mitral valve annulus was severely calcified and deformed. A protruding strut of the aortic bioprosthesis was limiting further safe conventional endoscopic mitral valve replacement (Fig. 1A). Following this, two pledgeted polyfilament U-shaped annuloplasty sutures were placed at the commissures of the annulus. Their main role was to make the annular shape more circular in order to reduce the risk of paravalvular leak (Fig. 1B). No leaflet resection was deemed necessary at this stage, as the anterior leaflet was found to be calcified, retracted and rigid and was therefore unlikely to cause any obstruction of the left ventricular outflow tract. Otherwise anterior leaflet resection should be considered, especially if it is long and pliable, in order to avoid any obstruction after valve deployment. Hegar dilators as well as measurements from transoesophageal echocardiography were taken into consideration for sizing. A 26 mm Sapien™ XT (Edwards Lifesciences) transcatheter aortic prosthesis was deployed using the transapical delivery system through the mini-thoracotomy, under full endoscopic vision (Figs 1C and 2A). The annuloplasty sutures were then passed through the valve frame and tied, in order to further secure it in position (Fig. 2B). The immediate postoperative outcome was very satisfactory (Fig. 2C).

Figure 1:

Intraoperative images taken with the endoscope. (A) View of the mitral valve. The severe calcification of the posterior annulus as well as the protruding strut of the aortic bioprosthesis (circle) can be appreciated. (B) Placement of one pledgeted polyfilament annuloplasty U-suture in each commissure. (C) Introduction and placement of the transcatheter aortic valve.

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Figure 2:

Intraoperative images taken with the endoscope. (A) Balloon inflation and deployment of the transcatheter valve. (B) Valve inspection after deployment. (C) Assessment of the result after water testing.

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RESULTS

Postoperative echocardiography confirmed optimal valve placement with no paravalvular leak. The patient was extubated 6 h after surgery. Her initial recovery was uneventful. Two months later, however, and despite the fact she was rehabilitating well, she passed away after a severe lung infection. During these events, transthoracic echocardiography confirmed a well-seated prosthesis with no paravalvular leaks and preserved left ventricular function.

DISCUSSION

Minimally invasive native mitral valve surgery can be performed by different approaches. Endoscopic non-rib spreading procedures are well established for complex mitral valve repairs and replacements [1]. Transcatheter mitral valve implantation has also been described. The valve can be delivered through the apex of the heart [2], through the left atrium under direct vision [3], through sternotomy [4] or using a robotic system [5]. Our report suggests that a combination of fully endoscopic and transcatheter techniques can be employed for the treatment of native mitral valve stenosis, particularly in patients with high technical and surgical risk where an extensive decalcification of the annulus could be more risky than beneficial. Endoscopic procedures offer optimal vision and the option of simultaneous additional repair techniques, without the cost of robotic consoles. They have, therefore, a role as they can optimize valve placement and reduce the risk of paravalvular leak; therefore, they should be considered in this group of patients.

Conflict of interest: none declared.

REFERENCES