Robert Bauernschmitt

Objective: Trans-catheter aortic valve implantation (TAVI) technology is rapidly evolving, with 412 procedures having been performed at our institution. Herein, we report a complete, prospective analysis of complications occurring during transvascular and trans-apical implantations with two different prostheses. Methods: Between June 2007 and June 2010, 412 patients (258 female, mean age 80.3 ± 7.2 years, logistic EuroSCORE (European System for Cardiac Operative Risk Evaluation) 20.2% ± 13.0%) underwent TAVI through either a retrograde (n = 252 transfemoral, n = 28 transaxillary, and n = 5 transaortic) or antegrade (n = 127 trans-apical) approach at our institution. The trans-apical access was chosen only in cases where transvascular implantation was not possible. As many as 283 CoreValve and 129 Edwards Sapien prostheses were implanted. Results: Thirty-day survival was 90.9%. Vascular complications occurred in 42 patients (10.2%). In four patients, lethal aortic root (n = 3) or abdominal (n = 1) aortic rupture occurred. Pericardial effusion developed in 53 patients (12.8%), which resulted in cardiac tamponade in 12 patients (2.9%). Twenty-three patients (5.6%) with valve malplacement were treated interventionally. In five patients (1.2%), emergency institution of cardiopulmonary bypass was required during the procedure for temporary support; all patients survived. Seventeen patients underwent re-intervention on the catheter valve (4.1%). Conclusions: With growing experience, complications with TAVI may be avoided by proper patient selection and skillful management. Other complications, when they occur, require a specific treatment algorithm to avoid delay in decision making. A considerable number of complications after TAVI require surgical treatment. Therefore, the ideal environment for TAVI procedures is a hybrid operating room, where a multidisciplinary team of surgeons, cardiologists, and anesthesiologists is best fitted to meet the current needs associated with TAVI technology. A reduction in complications was seen after 300 cases. This finding attests to the complexity of the procedure in addition to the experience required to reduce the incidence of complications.

The study aim was to assess long-term morbidity and mortality with special regard to prosthesis durability after aortic root replacement with the Hancock bioprosthetic porcine conduit. Between 1975 and 2004, a total of 81 patients (55 males, 26 females; mean age 58 +/- 18 years) underwent aortic root replacement with the Hancock conduit for aortic dissection (n = 22; 27%), ascending aortic aneurysm (n = 57; 70%), or porcelain aorta (n = 2; 3%). Twenty-five patients (31%) underwent an emergency operation, 12 (15%) presented with Marfan syndrome, and eight (10%) had undergone previous cardiac surgery. Concomitant procedures were performed in 26 cases (32%). The follow up was 98% complete; the mean follow up was 4.8 +/- 4.0 years (range: 1 day to 16.7 years), and the cumulative follow up was 403 patient-years. Actuarial event-free rates were calculated, and valve-related complications classified according to guidelines for reporting morbidity and mortality after cardiac valvular operations. There were seven (9%) operative deaths and four (5%) in-hospital deaths. Actuarial survival rates at five and 10 years (excluding operative deaths) were 77.0 +/- 5.3% and 54.0 +/- 7.5%, respectively. Actuarial freedom from aortic valve reoperation at five and 10 years was 98 +/- 1.6% and 64 +/- 10.2%, from structural valve deterioration 88.1 +/- 4.7% and 49.9 +/- 9.6%, from thromboembolic events 87.4 +/- 4.6% and 75.1 +/- 9.5%, and from major bleeding events 90.2 +/- 3.9% and 75.4 +/- 8.1%, respectively. Among redo procedures, the stentless Hancock valve could be excised without separating the synthetic graft from the left ventricular outflow tract, and a stented valve prosthesis thus implanted. Hence, it was possible to avoid a second Bentall operation. The long-term survival rates after aortic root replacement with the bioprosthetic Hancock conduit were reasonable for this demanding patient cohort. However, the durability of the prosthesis was inferior to that reported for the stented Hancock valve substitute. The key benefit of this bioprosthetic valved conduit was the simplified redo procedure.

The left-ventricular trans-apical access has become well established for trans-catheter aortic valve implantation, especially for patients in whom a retrograde trans-arterial implantation is contraindicated. We report on the short- and long-term implications of the apical-access-site-specific complications.

Although the long-term clinical outcome after aortic valve replacement (AVR) with the Sorin Mitroflow pericardial bioprosthesis has been well described, few data are available with regards to hemodynamic performance. On the basis of its specialized design, with the pericardium mounted on the outside of the stent, the Mitroflow valve is considered to provide optimal opening and orifice areas. Between February 2006 and April 2007, a total of 127 patients (66 females, 61 males; mean age 77.6 +/- 5.2 years) underwent AVR with the Mitroflow valve at the authors' institution. Echocardiography was performed at discharge in 91 patients, while a six-month follow up examination was conducted in 78 (including ergometer hemodynamics in 25 cases). The mean systolic pressure gradient (MPG) ranged from 19.7 +/- 3.3 mmHg (size 19 valve) to 12.4 +/- 2.4 mmHg (size 27 valve), and the mean effective orifice area (EOA) from 0.96 +/- 0.0 cm2 (size 19 valve) to 2.36 +/- 0.4 cm2 (size 27 valve). The incidence of mild-to-moderate and severe prosthesis-patient mismatch (PPM) was 33% and 10% at the six-month follow up. During exercise (25 W-100 W), the MPG increased from 17.1 +/- 3.6 mmHg to 23.6 mmHg in valve sizes 19 to 21, and from 12.2 +/- 3.6 mmHg to 15.9 +/- 2.5 mmHg in valve sizes 23 to 27. The effective orifice fraction (EOF = EOA/annulus area) was 38 +/- 7%. The Mitroflow valve exhibits an adequate MPG and EOA, as might be expected for a pericardial bioprosthesis. Of note, the gradient increase during exercise was low, especially for the larger valve sizes. Due to its special design, the Mitroflow prosthesis shows a large opening, as demonstrated by the high EOF. These data relating to the EOA of all prosthesis sizes may help surgeons to select the minimum prosthesis size in order to prevent PPM.

Clinically used valve prostheses are still associated with several limitations. The biological prostheses are limited due to their durability and mechanical valves need permanent oral anticoagulation. Tissue engineering could become a capable tool to create an „ideal” living heart valve with the potential to grow. This would be a matter of particular interest especially in paediatric patients. This article gives a short overview about current concepts, used cell types and clinical experiences with tissue engineered heart valves.