Transapical implantation of a novel self-expanding sutureless aortic valve prosthesis.

BACKGROUND AND AIM OF THE STUDY: To date, transapical aortic valve implantation has required a balloon-expandable stented valve prosthesis. More recently, a novel self-expanding sutureless stented bovine pericardial prosthesis has been developed which allows rapid aortic valve replacement via an open transaortic approach in humans. The aim of this animal study was to develop a reliable protocol to facilitate the transapical implantation of this self-expanding valve in a porcine model. METHODS: Off-pump transapical aortic valve implantation was performed through a left mini-thoracotomy using a bovine pericardial valve mounted on a self-expandable nitinol stent of size 21 mm and 23 mm in 11 pigs (average weight 60 kg). The crimped valve was introduced through the left ventricular apex using a flexible and steerable delivery sheath, using a three-step technique. Biplane fluoroscopy and transesophageal echocardiography were simultaneously used for guidance. Successful adjustment of alignment along three axes prior to deployment of the valve was accomplished in each animal. Deployments were performed during a period of rapid pacing. RESULTS: All valves were successfully deployed and functioned normally following transapical removal of the delivery system. Paravalvular leak was documented in one case (9.1%) due to prosthetic misalignment. There was no evidence of valve migration. Correct anatomic seating was confirmed during post-procedure necropsy. CONCLUSION: Successful transapical implantation of a novel self-expandable bovine pericardial valve was accomplished in 11 animals, without cardiopulmonary bypass. A flexible, steerable delivery system with a three-step release mechanism allowed precise positioning of the valve with a low rate of paravalvular leakage, and excellent device stability.

Systolic anterior motion after mitral valve repair: is surgical intervention necessary?

OBJECTIVE: The natural history and management of patients with systolic anterior motion after mitral valve repair are uncertain. METHODS: We performed a retrospective chart review and survey follow-up of all patients in whom systolic anterior motion developed intraoperatively after mitral valve repair. RESULTS: From January 1993 to December 2002, mitral valve repair was performed in 2076 patients, and in 174 cases (8.4%) systolic anterior motion was identified on intraoperative echocardiography. These patients form the study group. Initially, patients were managed with a combination of beta-blockade, vasoconstriction with phenylephrine, and/or intravascular volume expansion. Four patients had revision of repair because of persistent systolic anterior motion, and 3 additional patients had revision of repair because of mitral regurgitation from other causes. The median follow-up of the remaining 167 patients was 5.4 years (range 0-13.2 years). There were 2 late reoperations, but none were caused by systolic anterior motion or left ventricular outflow tract obstruction. Ninety percent of patients were in New York Heart Association class I, 7% were in class II, and 3% were in class III or IV. Echocardiograms were available for review in 93 patients at a median interval of 5.4 years (range 0.2-12.2 years); 13 patients had systolic anterior motion, and 4 patients had systolic anterior motion with left ventricular outflow tract obstruction. CONCLUSIONS: In this experience, most cases of systolic anterior motion resolved with conservative measures including beta-blockade, vasoconstriction, and fluid administration. Persistent systolic anterior motion with left ventricular outflow tract obstruction was documented in 2.3% of patients who had early systolic anterior motion, but late reoperation was not required. Furthermore, the clinical outcomes of patients with systolic anterior motion are comparable to the current norms for mitral valve repair. Ninety percent of patients were in New York Heart Association class I, 7% were in class II, and 3% were in class III or IV.