Following the first TAVI procedure in 2009 in Turkey with the ES prosthesis,[1] the MCV entered the market soon afterwards, and the first application was performed in the Istanbul Mehmet Akif Ersoy Hospital in 2011. We have implanted two MCV valves in patients in our center, and in this report, we will discuss the short-term results in light of the clinical available data.
A 29 mm Corevalve® aortic prosthesis was implanted via the transfemoral route. No postoperative complications were reported, and the patient was discharged on the seventh postoperative day after a one-night intensive care unit (ICU) stay.
Case 2– An 81-year-old obese female [body mass index (BMI): 41.7 kg/m2] with a 22-year history of severe COPD was admitted to the hospital with increasing dyspnea, despite having received extensive diuretic therapy for the previous five weeks. Echocardiography revealed severe aortic stenosis and mild-to-moderate mitral insufficiency. After considering the comorbidities, this patient was also scheduled for TAVI.
A 26 mm CoreValve® aortic prosthesis was implanted transfemorally, but a complete atr ioventr icula r (AV) block developed postoperatively. A previously used transvenous pacemaker was implanted temporarily, and a dual chamber rate adaptive (DDDR) permanent pacemaker was implanted on the second postoperative day. The patient had no other complications and was discharged on the fifth day. The detailed clinical findings of both patients are listed in Table 1.
Table 1: Preoperative and operative findings of the two cases
The technique
For a very detailed, critical anatomical examination,
echocardiography, multislice computed tomography
(CT), and angiography are performed, starting from the
left ventricular outflow tract (LVOT) and continuing to
the femoral arteries.
Under general anesthesia in the catheterization laboratory, a transesophageal echocardiography (TEE) probe and a transvenous pacemaker lead are inserted prior to the initiation of the procedure. Following systemic heparinization, we prefer to use an open femoral arteriotomy for access. A standard balloon aortic valvuloplasty is performed during a short period of rapid ventricular pacing, followed by the transfemoral insertion of an 18 French (F) sheath. The crimped bioprosthesis is then advanced across the native aortic valve. Exact positioning of the valve is done meticulously since the valve is functional even during partial deployment (Figure 1a). The tip is released last, only after confirming the final position of the valve (Figure 1b). The arteriotomy is then surgically fixed, and dual antiplatelet therapy (aspirin and clopidogrel) is administered for six months after the procedure.
Both of our patients were followed up for nine months. The first patient was New York Heart Association (NYHA) class II at the last visit and was only limited by his severe COPD. The second was NYHA class I. The transvalvular gradients were measured as 29/15 and 14/8 mmHg (peak/mean), respectively.
The mid-term results involving a patient in Canada with the ES prosthesis saw a primary success rate of 93.3% along with a 30-day mortality of 10.4%, and Rodés-Cabau et al.[3] reported survival rates in the first and second years of 76% and 64%, respectively.[3] Furthermore, in the European Placement of Aortic Transcatheter Valves (PARTNER) trial, valve implantation was successful in 96.4% of the patients in the transfemoral group, and the 30-day and six-month survival rates were 91.8 and 90.2% respectively.[4]
In another report involving the placement of a the third generation 18 F CoreValve® device, the procedural success and mortality rates were 98% and 0.9%, respectively. In addition, the cumulative mortality rates were 5.4% at 30 days, 12.2% at six months, and 15.0% at one year.[5]
Both Edwards Lifesciences Corporation and Medtronic Inc. have succeeded in decreasing the profile size of the valve to 18 F. The MCV is a porcine pericardial prosthesis on a self-expanding nitinol stent, whereas the ES is a bovine pericardial prosthesis on a balloon-expandable steel stent.
The longer stent skeleton of the MCV provides a second landing zone at the level of the sino-tubular junction. This structure also helps have better parallel positioning of the prosthetic valve and the aortic annulus. Together with the self-expanding nature of the stent, the MCV aims to decrease paravalvular leakage. On the other hand, this device is associated with a higher incidence of complete AV block that requires permanent pacemaker implantation. This is attributed to the lower seating structure of the valve within the LVOT. The self-expanding MCV also makes a second balloon dilatation during another period of rapid ventricular pacing unnecessary, thus attenuating the potential for stroke.
The MCV is approved for transfemoral and trans-subclavian routes while the ES is approved for transfemoral and transapical routes. The MCV has also marketed a 31 mm valve and will soon launch a 23 mm valve in a 16 F profile.
In conclusion, despite the lack of reimbursement policies, several centers are performing TAVI procedures in Turkey. A dedicated team of clinicians who are specifically trained for this purpose should handle the patient with maximum care and cognizance. Increased experience with the MCV together with improvements in the device technology will certainly create a potential for wider use in this country.
Declaration of conflicting interests
The authors declared no conflicts of interest with
respect to the authorship and/or publication of this
article.
Funding
The authors received no financial support for the
research and/or authorship of this article.
1) Yücel G, Paker T, Akçevin A, Sezer A, Eryilmaz A, Ozyiğit
T, et al. Transcatheter aortic valve implantation: the first
applications and early results in Turkey. [Article in Turkish] Turk Kardiyol Dern Ars 2010;38:258-63.
2) Vahanian A, Baumgartner H, Bax J, Butchart E, Dion
R, Filippatos G, et al. Guidelines on the management of
valvular heart disease: The Task Force on the Management
of Valvular Heart Disease of the European Society of
Cardiology. Eur Heart J 2007;28:230-68.
3) Rodés-Cabau J, Webb JG, Cheung A, Ye J, Dumont E,
Feindel CM, et al. Transcatheter aortic valve implantation
for the treatment of severe symptomatic aortic stenosis in
patients at very high or prohibitive surgical risk: acute and late
outcomes of the multicenter Canadian experience. J Am Coll
Cardiol 2010;55:1080-90. doi: 10.1016/j.jacc.2009.12.014.
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