Catheter-assisted heart valve replacement

Since autumn 2007, minimally invasive aortic valve replacement has been performed on the beating heart in risk patients in Grosshadern Clinic in a collaboration between the cardiac surgery clinic (director: Prof. B. Reichart) and medical clinic I (director: Prof. G. Steinbeck). A new hybrid operating theatre was built for these procedures. A modern angiography unit is built into this operating theatre so that the operation can be performed under sterile conditions with good imaging. Patients of advanced age (over 80 years) in particular, with numerous comorbidities (heart weakness, severe vascular calcification (“porcelain aorta“), previous bypass surgery, pulmonary hypertension, renal failure etc.) and therefore with a markedly increased perioperative risk (STS score > 10), are candidates for this procedure.

Illustration of a catheter-assisted heart valve

Basically, three methods are available:

1. Transfemoral aortic valve replacement

The CoreValve® system from Medtronic is currently employed. The patients are merely sedated but not intubated. Through the femoral artery, the patient’s narrowed aortic valve is first stretched with a balloon catheter. A biological heart valve made of porcine pericardium, which is incorporated in a self-expanding nitinol stent, is then inserted, again through the femoral artery, as far as aortic valve level and is released there.

2. Transapical aortic valve replacement

This procedure employs the Edwards Lifesciences system (SAPIEN™). This valve is a bovine pericardial valve which has been inserted conventionally for many years and has been modified for the minimally invasive approach. Under general anaesthesia, the patient’s chest is first opened through a ca. 7 cm skin incision below the left nipple and the apex of the heart is exposed. After puncturing the left ventricle, the patient's narrowed aortic valve is first stretched with a balloon catheter. The new heart valve is then advanced as far as the aortic valve level over another balloon catheter on which a folded stent with the biological valve has been mounted. Inflating the balloon unfolds the new heart valve and anchors it in the valve annulus.

3. Transaxillary aortic valve replacement

If neither of these procedures is possible, a further procedure is available in individual cases where the heart valve is advanced through a large artery in the arm. This operation also uses the Medtronic CoreValve® system.

All of these procedures have advantages and disadvantages and are chosen individually depending on the patient’s risk profile. The medium-term results are good in patients treated so far. To date (April 2010), more than 180 CoreValve® and about 80 SAPIEN™ THV have been implanted at Grosshadern Clinic.