Transcatheter aortic valve replacement - a new frontier in cardiovascular medicine

Sep 1 2008

Replacing heart valves without the substantial trauma of opening the chest and the heart were little known concepts until the groundbreaking pulmonary and aortic transcatheter valve replacements performed during 2000 and 2002, respectively by Philipp Bonhoeffer and Alain Cribier.

Today, advanced development programs for less invasive treatment of the aortic, mitral and pulmonary valves are coming to fruition and herald a period of great transformation in cardiovascular medicine both for patients and for their physicians.

Current experiences with one of the two CE Marked devices, the CoreValve ReValving® System for Percutaneous Aortic Valve Replacement (PAVR) have proved to be an overall success. This device consists of a porcine pericardial valve prosthesis mounted on a self-expanding Nitonol frame, which is delivered by means of an 18 French size (6mm) catheter. Today, the procedure can be performed in the cath lab by the interventional cardiologist under local anesthesia, without the use of surgical cut-down/repair (with pre-closing), without heart-lung bypass, and with the heart at normal sinus rhythm during valve placement.

A first safety & efficacy study (August 2005 - August 2006) enrolled 65 patients. A second study (October 2006 - June 2007) enrolled 112 patients. The study criteria focused on severe aortic stenosis (AVAI≤0.6cm2/m2) in patients older than 75 years, or with Logistic EuroSCORE (LE) ≥15%, or older than 65 years with multiple co-morbidities. Endpoints considered procedural success/morbidity/mortality, as well as 30-day and long-term outcomes.

Preliminary analysis of 175 patients enrolled in the combined studies (21F+18F) represent a combined mean theoretical surgical risk level of LE 24%, a mean age of 82 years, a mean pre-procedural AVA of 0.61cm2, and Mean Gradient (MG) 44.3mmHg. About one quarter of patients were deemed totally inoperable and 60% were female. 79% of patients were in NYHA class III/IV.

Overall procedural success was 91%. MG decreased to 7.9mmHg while AVA increased to 1.62cm2, with 86% of patients moving to NYHA class I/II. Procedural and procedure related mortality were <1% and 8% respectively. Total 30-day mortality was 15%. Mean follow-up to 12 months (range 10 to 32 months) detects a further 16% mortality among these octogenarians, none valve related. At last follow-up, substantially improved quality of life was documented for 85% of surviving patients with MG at 11mmHg, Ejection Fraction of 56%, and 88% in NYHA class I/II. No valve dysfunction or migration was observed either post procedurally or at long term follow up.