Transcatheter Aortic Valve Implantation:
Value of a Single-center Prospective Registry
Marcos Fernando de la Vega
Servicio de Hemodinamia Hospital Córdoba, Clínica Sucre. SHECI-CONCI-CARPINELLA
Córdoba, Argentina E-mail
Recibido 17-AGO-2014 – ACEPTADO 01-SETIEMBRE-2014. The author declare not having conflicts of interest
Editorials reflect the opinion of authors,
not necessarily those
of the FAC Journal
Rev Fed Arg Cardiol. 2014; 43(3): 113-115
Degenerative aortic stenosis is the most frequent valve pathology in Western countries . When this valve disease is severe (maximal velocity of 4 m/sec, valve area <1 cm2 and medium gradient >40 mmHg) and some of the most relevant symptoms of this identity appear: dyspnea, syncope or angor, survival is of 2, 3 and 5 years respectively , where undoubtedly, the patient should be treated as soon as possible , by surgical aortic valve replacement, with class I indication, level of evidence A. However, due to the most frequent etiology of aortic stenosis being the degenerative one, the age of the patients is in general, advanced (4.6% of individuals ≥75 years), so they frequently present associated co-morbidities (left ventricular dysfunction, concomitant CAD, previous CABG, chronic obstructive pulmonary disease, etc.) that increase surgical risk and post-operative morbi-mortality, or present conditions that make they inoperable (e.g., hostile thorax), so up to a third of the candidates to surgical aortic valve replacement are rejected to undergo this procedure ; so this is the main reason for the emergence of a new therapeutic alternative: transcatheter aortic valve implantation (TAVI).
Since Alain Cribier made the first percutaneous implant of a human aortic valve in 2002 , the procedure expanded rapidly, with more than 100,000 implants currently, thanks to the contribution by single-center registries (such as the one published in this issue of the Revista de FAC), multi-center registries (Spanish, French, German, Argentine, etc.) and randomized studies (PARTNER I, COHORT B that compared the best medical treatment, including aortic valvuloplasty vs. TAVI with the Edwards Sapien valve in inoperable patients ; COHORT A that compared TAVI with the Edwards Sapien valve vs. surgical aortic valve replacement  and US PIVOTAL TRIAL that compared TAVI with the CoreValve valve vs. surgical aortic valve replacement , in patients in high risk), which made of this therapeutic modality, a new alternative for a group of patients that previously had no other option than the natural evolution of the aortic valve disease.
The greater share of data comes from the implant of percutaneous first-generation valves (Figure 1). In Argentina, the CoreValve valve (Medtronic) was the one most generally used to this moment, since the Edwards Sapien valve did not enter the country, due to the possibility of bovine pericardium being contaminated with prions, that may cause bovine spongiform encephalopathy or Creutzfeldt-Jakobdisease.
Figure 1. Differential features between first-generation valves
Currently, there are more than 15 valves being developed and in process of evaluation in different trials and international registries. In 2013, the JenaValve valve of porcine pericardium, of nitinol, self-expandable, repositionable and retrievable, and that uses the transapical access to implant it, was approved in Argentina by ANMAT.
To indicate the JenaValve valve, a multidisciplinary team is required to achieve in the ideal candidate, the best result immediately and in the long run. Once the diagnosis of symptomatic valve disease has been confirmed, first the surgical risk of the patient is evaluated through the logistic EuroScore I (ES)  and/or STS score , with an ES ≥15 and a STS ≥10 being considered a high surgical risk, with the latter score being the most representative of reality.
We should remember that there are other situations responsible for the surgical condition of the patient not considered in the scores, such as the fact of having a hostile thorax (kyphoscoliosis, irradiation, burns, multiple sternotomies), porcelain aorta, advanced liver disease (Child-Pugh class C/cirrhosis), right ventricular dysfunction (TAPSE <15 mm; end systolic area >20 cm2), mammary bypass adhered to the sternum or within 3 mm of the posterior table and the fragility of the patient that entails weakness, exhaustion, malnutrition, poor resistance, loss of independence and inactivity, established criteria by the group of experts of the VARC 2  that also considers: walk of at least 5 minutes, strength of handshake, BMI 20 kg/m2, and/or weight loss 5 kg/year, albumin of 3.5 g/dl and cognitive dementia.
We should consider whether there are clinical or anatomical contraindications, or relative to the transcatheter aortic valve implant (TAVI) (Table 1).
Table 1. Clinical, anatomical contraindications, and those relative to the TAVI
We should take into account whether the patient concomitantly presents angiographically proven CAD, and if the patient presents significant lesions to preferably treat them within 30 days before the TAVI, according to the current recommendations by experts, until the ACTIVATION trial results are known, which seeks to answer when is the optimal time for revascularization.
With graduated pigtail catheter, the aortic ring and the proximal portion of the aorta are assessed (aligning the three aortic valve cusps), as well as vascular accesses that currently should be at least 6 mm in diameter (iliofemoral and/or subclavian axis), since the release system is of 18 French (F).
Transthoracic Doppler echo also allows assessing the RV outflow tract, the aortic ring, sinus and proximal portion of the thoracic aorta, ventricular function, valve gradient, the area, contractile reserve with stress-echo if necessary. It is advisable to perform transesophageal echo (TEE), and finally multislice computed tomography (MSCT) that contributes the most accurate dimension of the aortic ring, showing its oval shape, aware that if one chooses the right measure, it prevents one of the most dreaded complications; i.e. post-implant aortic insufficiency or ring rupture, and moreover, it allows choosing the device to be used, where for 18-29 mm rings, percutaneous valves N° 23, 26, 29, 31 of CoreValve are used; for 18 to 27 mm rings, percutaneous valves N° 23, 26 and 29 of Edwards Sapien are used; and for 21 to 27 mm rings, percutaneous valves N° 23, 25 and 27 of JenaValve.
The multidisciplinary team should consider if the patient is a candidate to plan the implantation, with intradural or general anesthesia, or if the femoral approach will be the first option.
In Argentina, the approach is preferably by surgery, since percutaneous access and its percutaneous closure system with Prostar is expensive and it requires a proper learning curve, and although in international studies there are no differences, the Argentine registry, presented in the III Simposio CACI@FAC (June 2012, Salta, Argentina), showed a lower rate of vascular complications, quite a significant fact because it does not increase the morbi-mortality of the procedure. There are other access options: transaortic, subclavian, or transapical; the latter a predictor of mortality as shown by the pilot European registry 2011-2012 .
The rate of success of TAVI is close to 98% with an evident improvement of functional class. Post-implant, 85% are in functional class I-II, the area increases and gradient decreases, parameters that are maintained over time, as shown by Quarchioni et al, in the paper published in this issue of the Revista de FAC, also corroborated by our experience in France , and in the international randomized studies (PARTNER Trial and US Pivotal Trials). See the paper published
But as with any therapeutic procedure, it is not without complications, with the most frequent one in national and international registries, being the need of a permanent pacemaker (15-40%) in the CoreValve implants, and 3-5% in the case of implanting an Edwards Sapien valve and/or surgery. In 3-18% of the cases, vascular complications appear, in 4-9% acute renal failure (ARF), 2-3% aortic insufficiency (AoI), stroke in 2-5%, AMI 1%, prosthesis migration 1%, cardiac tamponade 1%. From all these complications, the vascular ones, AoI, ARF, stroke and AMI (occlusion of coronary vessel during the procedure) arise as independent predictors of mortality (single-center registry in a hospital of Public Care of Paris, presented in 2012 in Mexico DF, within the framework of the annual meeting of the SOCIME and the XVIII Congreso del SOLACI).
To minimize these complications, release systems of 14 F are used, as well as brain protection systems, use of contrast to obtain images is prevented when possible, and new valve designs are used to prevent paravalvular leaks.
Currently, symptomatic severe aortic stenosis, although treated in an optional manner with surgical aortic valve replacement, it is necessary to consider in the therapeutic algorithm, the TAVI for those patients in high surgical risk with class IIa indication, level of evidence B, and for inoperable ones, with class I, level of evidence B .
The analysis of in-hospital mortality, in Cohort A of the PARTNER trial, at 30 days, 6 months, 12 months, and 48 months shows TAVI as a technique as safe as surgery in patients in high risk, a fact that encouraged investigators, to perform trials (PARTNER 2, SURTAVI) in patients with intermediate risk (STS of 4-10).
This therapeutic alternative, that is feasible, safe and efficient, emerged to stay, with possibilities to expand in a near future to patients in intermediate risk.
Because of what was presented here, we should highlight the contribution of this registry, published in this issue of the Revista de FAC, that shows the experience of a center, that even with the limitations indicated by the author, contributes the experience and results obtained in an institution as of great value, which are added and enrich those from so many others.
The Heart Team of the Henri Mondor Hospital, the team of the Hospital Córdoba, Clínica Sucre, and Conci-Carpinella.
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