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Percutaneous valve therapy in 2010

ESC Congress 2010

Valvular Heart Diseases

Dr Ted Feldman from Evanston hospital presented the data on percutaneous mitral valve repair. The first of these was data related to surgical edge-to-edge mitral repair (ALFIERI procedure), which led to the development of the clip method for percutaneous edge-to-edge repair. The percutaneous procedure (mitral clip) is a combined effort of operators and anaesthesiologists, echocardiographers for the EVALVE trial and studies. The two main aetiologies of mitral regurgitation that were evaluated were degenerative and functional mitral regurgitation. For the European experience so far has included 994 patients, and the total experience for the EVEREST studies has included 1,754 patients.

The main findings with the EVALVE experience have been a reduction of left ventricular size, and a reduction of septal to lateral dimension. An important aspect of this procedure is that if it does not work, or a problem arises, the surgical option, i.e. the need to go to surgery, is not hindered. The patients are stable throughout the procedure and the safety profile is very similar to other percutaneous procedures. There have been no embolisations and partial clip detachment has occurred in <3% of patients. The clinical benefits have been favourable left ventricular remodelling, less need for heart failure hospitalisation and better one year survival.

The first repair technology trial has been completed. These data have been published in JACC 2009;54(Aug 18):686-694. The actual increase in survival has been from 55.3% to 76.4%, vs matched controls, p<0.037. In follow up studies up to 5 years, not in the randomized trial, a reduction has been observed in pulmonary artery systolic pressure from 79 mmHg to 55 mmHg. This benefit of reduction in pulmonary artery systolic pressure and in LV dimension has been maintained up to 5 years in patients who have been followed for that long. Currently, the EVEREST 2 randomised trial is in progress, which will compare the mitral clip to surgery. So far, the comparison of mitral clip vs surgery is among the population with degenerative and functional mitral regurgitation, they are older than in a matched group from the STS database. Left ventricular remodelling has occurred both with the mitral clip and with surgery, but the mitral clip has provided better NYHA class and quality of life as judged by the SF-36 scale.

In summary, the treatment of mitral regurgitation has been between medical management and surgery and in patients who have surgery, the trade-off is between repair vs replacement of the valve. The mitral clip device will provide a third option to consider for the treatment of mitral regurgitation once the procedure has been approved for routine clinical use.

How to select patients – HR Kapadia (Cleveland USA)

The selection of patients for percutaneous mitral valve procedures requires considerable experience and evaluation of all aspects of the patient, as well as of the procedures that are available. In the evaluation of patients, important points are symptomatology, clinical heart failure, LV function and other comorbid conditions. Also important is the consideration of the cardiovascular hemodynamics, in addition to the clinical evaluation, which also requires detailed and considerable skill in evaluating high quality echocardiographic data. If necessary, in some patients, there is a need to perform coronary angiography and evaluation of whether it will be just a mitral valve procedure, or mitral valve plus myocardial revascularisation. Additional study using more advanced technologies of CT and MRI may be needed in selected patients.

In this presentation by Dr. Kapadia, who works at the Cleveland Clinic, an institution where there is a large volume of mitral valve surgical experience and evaluation, in response to a question from the audience, Dr. Kapadia emphasised that before the percutaneous procedures are performed, evaluation of the patient by a surgeon experienced in the surgery of mitral regurgitation is an important part of the evaluation process. The decision to perform percutaneous repair is based on a judgement and consideration by the various staff members involved in the process.

Current status in percutaneous aortic valve therapy - EM Tuzcu, (Cleveland USA)

Trans aortic valve implantation (TAVI) started out after the initial experimental animal work with the first procedure in humans, which was successful. The experience with the Edwards Sapien valve has gone through a stage of feasibility, randomized trials that are in progress, and in Europe, with post-marketing evaluation. There are several studies that have been performed, including the REVIVE/REVIVAL study, VANCOUVER, PARTNER, SOURCE, the total Canadian experience and the French registry. The initial success rate was between 85 and 90%, which has gradually improved and the latest is the French registry includes 244 patients, with a 97% success rate. At baseline, 57% of the patients in these studies were in NHYA class IV, 9% in class III and the remainder in class II. 18 months after the procedure, 50% of the patients are in class I or asymptomatic, 17% in class II, 25% in class III and only 8% in class IV. A consistent improvement overall in left ventricular ejection fraction has been demonstrated, such that about 60% of the patients have normal LV function, and this improvement has been maintained out to 12 months of follow up.

The complication rate is low, and has improved over the years and in the latest French registry and the UK registry, vascular complications occur in about 5%, stroke in 3 to 4%, myocardial infarction in 1 to 2%. The need for permanent pacemaker implantation has occurred more with the CoreValve than with the Sapien valve, and may be needed in as many as 7 to 10% of patients. Incidence of aortic regurgitation on follow-up was presented at the TCT meeting last year and it shows that 11% of patients had no aortic regurgitation, 43% had class I aortic regurgitation, 37% had class II, class III in 9%, and class IV in 1%. In these patients, a consistent reduction of aortic valve gradient ranged from 55 mmHg to 10 mmHg at 6 months, and an increase in aortic valve area from 0.55 cm2 to 1.6 cm2.
The TAVI procedure can be done from a peripheral artery, which most commonly has been the transfemoral route, and in general, the 12 month survival has ranged from 73% to 81%. A major cause of the mortality in the first 12 months has been the presence of associated comorbid conditions in more than half of the patients. The two main types of valve in use are the Edwards Sapien valve and the Core valve. In patients in whom the entry of the valve from the peripheral artery is not feasible, surgeons have been using the apical method, which is an open thoracotomy with introduction of the replacement valve from the apex of the left ventricle.

The European experience with the Edwards Sapien valve has been documented in the SOURCE registry, where the 30 day survival with the trans-apical method was 89%, and in the transfemoral approach 94%. One year mortality was 28% and 19% respectively. The Core valve results have been similar, except for a much higher incidence of the need for permanent pacemaker implantation, which has ranged from 18% to 42%. There are 2 randomized trials being conducted with the Edwards Sapien valve, in the first, the comparison is between traditional surgical valve replacement and TAVI, and the other compares TAVI and medical treatment, when surgical aortic valve replacement is not feasible. These two randomized studies are in progress, the entry has been completed, and within the next 2 to 3 years, the analysis will be completed and the randomized trial data will be published.

Selection of patients - V. Delgado (Leiden, NL)

The commonest procedure with the percutaneous aortic valve replacement has been for aortic stenosis, in whom surgery has not been considered to be an option, or surgery was predicted to be at very high risk. All these patients have severe aortic valve stenosis. The valve has been calcified and left ventricular function has been impaired, and the most striking thing has been the associated comorbid conditions which have put the patients at very high risk for surgery. There are several high risk comorbid conditions. The most common ones include renal failure, and the need for dialysis, severe hypertension, diabetes, previous cerebrovascular complications, and COPD.

The selection of patients is based on an initial clinical evaluation of the patient, to assess the severity of aortic stenosis, state of LV function, and other comorbid conditions. The first investigative procedure is always a transthoracic echocardiogram, supplemented by trans-oesophageal echo if it is considered necessary. The other techniques that are important and in many instances essential, include CT, which provides an evaluation of the shape and size of the aortic annulus, the distance from the aortic annulus to the origin of the coronary arteries, atherothrombosis of the aorta, and the shape, size and distortion of the aorta down to the femoral artery, which becomes important for the insertion of the valve from the peripheral artery. Magnetic resonance imaging (MRI) has been used when satisfactory images have not been obtained by CT scan. Major advances have occurred with the development of smaller catheters, which make insertion and positioning much easier.




Percutaneous valve therapy in 2010
The content of this article reflects the personal opinion of the author/s and is not necessarily the official position of the European Society of Cardiology.