Transcatheter Aortic Prothesis Implantation for the Treatment of Severe Aortic Stenosis

PICHON-RIVIERE, A.; AUGUSTOVSKI, F.; GARCIA MARTI, S.; ALCARAZ, A.; LOPEZ, A.; BARDACH, A.; CIAPPONI, A

Documento de Evaluación de Tecnologías Sanitarias

IECS

Año: 2012 p. 1 - 30

1668-2793

Aortic valve stenosis is common in the elderly. It is usually an asymptomatic process with minimal associated mortality. However, when stenosis is severe, it presents symptoms which have high morbidity and mortality, associated to frequent hospitalizations and a significant decrease in quality of life.Patients with aortic stenosis receive treatment when it is symptomatic or severe and the treatment choice is based on the patient´s comorbidities, age and the surgical risk he/she presents. The treatment of choice is surgical aortic valve replacement. For those cases where conventional surgery is contraindicated, the treatment choice is controversial. It can be either medical therapy or balloon aortic valvuloplasty (BAV), although its effectiveness is not conclusive. The use of BAV has also been proposed as a "transition", prior to performing a definite procedure. Transcatheter aortic valve implantation (TAVI) is a minimally invasive percutaneous procedure which is proposed as an alternative for this subgroup of patients.TechnologyTAVI is a minimally invasive procedure, performed under general anesthesia in which, by means of a catheter, an expandable stent with a bioprosthetic tissue valve is placed. This catheter may be inserted through the femoral artery or through the heart apex. It requires the participation of multidisciplinary team due to the wide variety of complications that may arise. TAVI is approved in the U.S, Europe and Argentina.PurposeTo assess the available evidence on the efficacy, safety and coverage related aspects regarding the use transcatheter aortic valve prosthesis for severe aortic insufficiency treatment.MethodsA bibliographic search was carried out on the main databases: DARE, NHS EED, on Internet general search engines, in health technology evaluation agencies and health sponsors. Priority was given to the inclusion of systematic reviews; controlled, randomized clinical trials (RCTs); health technology assessments and economic evaluations; clinical practice guidelines and coverage policies of other health systems.ResultsThis report included a systematic review, 2 RCTs, one clinical practice guideline and a health technology assessment report. In addition, 3 case series and non-randomized comparative studies were included to assess TAVI after BAV.In 2011, the PARTNER group of researchers published one RCT which included 699 people at high risk of surgery (mean age 84 years old) with severe aortic stenosis, to receive TAVI or valve replacement through open surgery. No differences were found in the mortality rates for any cause within 30 days and at one year follow-up. At 30 days, severe vascular complications were found in the TAVI group (11.0% vs. 3.2%, P<0.01). In 2010, the same group published one RCT with 358 patients (mean age 83 years old) with non-surgical aortic stenosis to undergo TAVI vs. not TAVI, (most underwent balloon valvuloplasty). Lower mortality rates for any cause were found at one year follow-up in the TAVI group (30.7% vs. 50.7%; p<0.01). Among survivors, the ones in the TAVI group had fewer cardiac symptoms (25.2% vs. 58.0%; P<0.01). However, at 30 days there were more severe heart complications in the TAVI group (16.2% vs. 1.1%, P<0.01), with a higher stroke incidence (5.0 vs. 1.1%; p=0.06), not reaching statistically significant differences.In 2011, one systematic review included a case series of patients with severe aortic stenosis (range 80-85 years) who underwent TAVI. The rate of major complications ranged between 0% and 12%. Survival at one year was higher in the group undergoing TAVI than in the medically treated patients (p=0.01).Three studies were found which analyze case series where BAV was performed as a "transition" to TAVI. Besides, these cases were compared with those of patients directly undergoing TAVI, because they were in a condition to have this intervention performed from the beginning. Survival, 30 days post-TAVI, in those who underwent prior BAV was 94%, with no statistically significant differences compared to those undergoing TAVI without prior BAV, although only the patients who could finally undergo TAVI in this group were taken into consideration.In 2011, the American College of Cardiology Foundation (ACCF) and the Society for Thoracic Surgeons (STS) consider that, although TAVI has the potential to become a valid therapy for patients with valvular pathology, there is still little scientific evidence to make it an adequate option beyond clinical research trials.The health sponsors consulted agree that TAVI is a medically necessary procedure for people with severe symptomatic valvular stenosis who can not undergo valve replacement surgery.TAVI is approximately AR$16,000 (Argentine pesos, May/2012) considering expenses and medical fees plus U$S 36,000 (U.S. dollars May/2012) of the valve cost. Conventional valve replacement is about AR$16,000.ConclusionsFor those patients at low or moderate surgical risk, surgical aortic valve replacement is the treatment of choice.For patients at high surgical risk or in those where surgery is not possible, there is no consensus on what the best conduct should be. The results of this report come mainly from two RCTs. One of these RCTs compared TAVI against conventional surgery in patients at high surgical risk and in this group TAVI did not prove to be better than conventional surgery, or even it could present a higher adverse event risk. Therefore, even for those cases at high surgical risk, surgery may continue to be the best alternative for many patients. For those cases where surgery is not a possible option or the patient rejects it, the options are medical treatment, balloon angioplasty or TAVI. The second RCT included in this report assessed TAVI in a group of patients who were not considered surgical candidates. In this study, the comparator was a group of patients who mainly underwent balloon valvuloplasty. The TAVI group presented better results, but their interpretation should be cautious since balloon valvuloplasty is now being questioned due to the uncertainty regarding its potential effectiveness and its adverse event profile.No conclusions can be drawn regarding post-BAV TAVI effectiveness since the results come from observational studies evaluated at short term. In summary, in those patients where conventional surgery is not possible, the available evidence does not allow to clarify what the best conduct should be.