Tutorial
Direct surgical transcatheter heart valve implantation in a calcified mitral valve
Surgical transcatheter stent-valve implantation in severely calcific mitral valves represents a bail-out technique for avoiding ventricular rupture and calcium embolization in patients with a high surgical risk profile. In this video tutorial, we present the transcatheter implantation of a valve in a severely calcific mitral valve annulus, under direct surgical vision, using an anchoring stitch technique to secure the stent-valve to the mitral annulus.
Mitral annular calcification is a chronic degenerative process of the mitral valve ring. It can be associated left ventricular rupture during mitral valve replacement, which has a mortality rate of up to 86% . This life-threatening complication occurs as a result of localized trauma and hematoma due to deep annular decalcification, in older patients in particular, when it is not possible to preserve the posterior leaflet, chordae, and papillary muscle. To treat those who present with severe mitral annular calcification, the transcatheter valve was introduced as an alternative therapeutic option. Care must be taken during implantation to minimize complications such as embolization, paravalvular leaks, and left outflow tract obstructions.
A 73-year-old woman with severe comorbidities (hypertension, COPD, alcohol abuse, dyslipidemia, anxiety-depressive disorder, cognitive decline, peripheral arteriopathy) was referred for syncope, dyspnea, and heart failure (NYHA III). Transthoracic echocardiogram showed rheumatic mitral valve stenosis with a severe asymmetric annular calcification: peak and mean gradients were 20 and 13 mmHg respectively. A normal left ventricular function of 60% was assessed, with severe pulmonary hypertension of 80 mmHg. Preoperative angiography showed critical stenosis of the circumflex coronary artery. The calculated Society of Thoracic Surgeons (STS) risk score was 7.6% and the Euroscore II was 13%.
Transcatheter heart valve
The most commonly used transcatheter valves for implantation in a calcific native mitral valve are the SapienTM family (Edwards Lifesciences, Irvine, CA, USA), the Lotus™ (Boston Scientific Inc., MN, USA), the Direct Flow™ (Direct Flow Medical Inc., CA, USA) and the InovareTM (Braile Biomédica, Brazil) (Table 1) [2]. The routes for delivery of the transcatheter valve into the mitral valve position are the transapical and transseptal approaches or the open transatrial direct approach.
Table 1. Transcatheter stent-valves used for deployment in the native mitral valve.
|
Transcatheter Stent-Valve |
Leaflets |
Expansion Design |
Access Route |
Size |
Introducer Sheath Size |
|
Edwards Sapien XT Edwards Sapien 3 |
Bovine pericardium |
Balloon expandable |
Transapical, transaortic, transaxillary, trasfemoral |
20mm 23mm 26mm 29mm |
TF 14F – 16F TA 18F – 21F |
|
Boston Scientific, Lotus* |
Bovine pericardium |
Controlled mechanical expansion |
Transfemoral |
23mm 25mm 27mm |
18F (small) 20F (large) |
|
Direct Flow Medical, Direct Flow* |
Bovine pericardium |
Inflatable and deflatable support structure |
Transfemoral |
23mm 25mm 27mm 29mm |
18F |
|
Inovare, Braile Biomédica |
Bovine pericardium |
Balloon expandable |
Transapical Transfemoral |
20mm 22mm 24mm 26mm 28mm |
20F – 22F |
|
* No longer available in the market |
|||||
The Sapien and Inovare are balloon-expandable aortic transcatheter heart valves (THVs) and are mounted upside down in the delivery system in the calcific mitral annulus [2, 3]. The Lotus and Direct Flow are self-expandable aortic THVs designed for transfemoral delivery that are implanted in calcified native mitral valves utilizing the transapical access route [4, 5].
Valve sizing
The mitral annulus is saddle shaped, with unique non-planar geometry. During percutaneous interventions preoperative imaging is of paramount importance in order to size the correct valve for implantation. Echocardiography and CT scans are the most frequently used techniques and they can also be used to produce a 3D printed physical model of the annulus for a bench-test simulation.
The unpredictable behavior of calcium under the radial force of a balloon valve (dilatation/cracking) can make transcatheter stent-valve implantation in the calcific annulus a challenging procedure to perform. Sizing during deployment of a transcatheter valve under direct vision should follow the common rules of open heart surgery using a surgical sizer and Hegar dilator.
1 - Preoperative planning (0:00)
After preoperative evaluation and risk assessment a decision was made by the heart team to proceed with CABG and surgical transcatheter stent-valve implantation under direct vision due to the high risk of calcium dislodgement during the valve and annulus decalcification.
2 - Direct surgical THV technique in a calcified mitral valve (2:48)
A standard sternotomy was performed. Cardiopulmonary bypass was started with bicaval cannulation, and a single dose of del Nido cardioplegia was used. After the anastomosis of a vein graft to the obtuse marginal branch, a standard left atriotomy was performed to expose the calcified mitral valve. The anterior leaflet was removed and 3 guiding sutures (3-0 polypropylene U-stitches with pledgets) were placed at the commissures and at the posterior leaflet midpoint.
A 29-mm balloon-expandable stent-valve (CE Sapien™ 3) was positioned and deployed under direct vision with the stent frame 3 mm over the mitral annulus into the left atrium. The 3 stitches were placed through the valve frame and were tightened to secure the transcatheter valve to the mitral annulus and avoid paravalvular leak.
An alternative technique for securing the valve to the annulus was described during implantation of sutureless aortic valve and this concept could be adapted for use in cases like ours, using the transcatheter stent-valve as a sutureless valve . An additional 3-0 polypropylene purse-string suture across the mitral annulus can be used around the stent-valve to prevent embolization and paravalvular leaks .
In our current case, the post-procedure echocardiogram showed a well-positioned prosthesis without leaks. The patient was extubated immediately after the procedure and the postoperative course was uneventful. The patient was discharged on postoperative day 8 and the predischarge echocardiogram confirmed optimal stent-valve positioning and functioning, without left ventricular outflow tract obstruction.
Results
A global registry recently reported the results of a first series of patients (n=64) undergoing this procedure . The embolization rate into the left atrium was 6% (4 out of 64). In all these cases, the embolizations occurred at the beginning of the surgical procedures and in direct transatrial cases; fixing the valve to the annulus helps prevent valve embolization. The reported mean mitral valve gradient was 4±2.2 mmHg and the orifice area was 2.2±0.95 cm2. The left ventricular outflow tract (LVOT) obstruction rate was 9.3% (6 out of 64) with hemodynamic worsening after valve deployment (mean peak LVOT gradient was 72 mmHg). The highest procedural success was achieved with the direct surgical transatrial approach (88.9%). The success rate for the transapical route was 71.4% and it was 65.4% for the transseptal technique .
Discussion
Percutaneous implantation has the advantage of being a minimally invasive approach and patients experience faster recovery after surgery. The main limitation of the percutaneous approach is the impossibility of securing the valve to the annulus, which leads to an increased risk of embolization and paravalvular problems. New transcather valves, such as the CardiAQ valve (CardiAQ Valve Technologies, Inc., Edwards Lifesciences), the FORTIS valve (Edwards Lifesciences) and the Tiara valve (Neovasc Inc., Richmond, British Columbia, Canada) are designed to overcome these complications and to prevent LVOT obstruction.
Transcatheter mitral valve implantation in cases of a severely calcified mitral annulus is technically feasible under direct vision in high-risk or frail patients, and has the advantage of placement of anchoring stitches between the stent and the annulus.
Clinical and hemodynamic follow-up is mandatory in order to evaluate the performance of stent valve prostheses in the mitral position and for this reason an FDA-approved Investigational Device Exemption trial was recently started (ClinicalTrials.gov Identifier NCT02370511) to assess the safety and feasibility of this promising approach.
- Deniz H, Sokullu O, Sanioglu S, Sargin M, Ozay B, Ayoglu U, et al. Risk factors for posterior ventricular rupture after mitral valve replacement: results of 2560 patients. European journal of cardio-thoracic surgery : official journal of the European Association for Cardio-thoracic Surgery. 2008;34(4):780–4.
PubMed Abstract | EJCTS Full Text - Guerrero M, Dvir D, Himbert D, Urena M, Eleid M, Wang DD, et al. Transcatheter Mitral Valve Replacement in Native Mitral Valve Disease With Severe Mitral Annular Calcification: Results From the First Multicenter Global Registry. JACC Cardiovascular interventions. 2016;9(13):1361–71.
PubMed Abstract | Publisher Full Text - Ferrari E, Niclauss L, Locca D, Marcucci C. On-pump fibrillating heart mitral valve replacement with the SAPIEN XT transcatheter heart valve. European journal of cardio-thoracic surgery : official journal of the European Association for Cardio-thoracic Surgery. 2014;45(4):749–51.
PubMed Abstract | EJCTS Full Text - Meller tF, Sinning JM, Werner N, Welz A, Grube E, Nickenig G, et al. First-in-man transapical mitral valve replacement using the Direct Flow Medical(R) aortic valve prosthesis. European heart journal. 2015;36(31):2119.
PubMed Abstract | Publisher Full Text - Lim ZY, Boix R, Prendergast B, Rajani R, Redwood S, Hancock J, et al. First reported case of transcatheter mitral valve implantation in mitral annular calcification with a fully repositionable and self-expanding valve. Circulation Cardiovascular interventions. 2015;8(11):e003031.
PubMed Abstract | Publisher Full Text - Ferrari E, Siniscalchi G, Tozzi P, von Segesser L. Aortic Annulus Stabilization Technique for Rapid Deployment Aortic Valve Replacement. Innovations (Phila). 2015;10(5):360–2.
PubMed Abstract | Publisher Full Text
Authors
Michele Gallo, Stefanos Demertzis, Torre Tiziano and Enrico Ferrari
Author Affiliations
Cardiac Surgery Unit, Cardiocentro Ticino Foundation Via Tesserete 48, 6900 Lugano, Switzerland
Corresponding Author
Enrico Ferrari, MD, FETCS
Cardiac Surgery Unit, Cardiocentro Ticino Foundation Via Tesserete 48, 6900 Lugano, Switzerland
Phone: +41 (0)79 3101386
Email: enricoferrari@bluewin.ch
© The Author 2018. Published by MMCTS on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.
