Emergent valve replacement after circular mapping catheter entrapment in mitral valve apparatus.

We present the case of a 47-year-old male patient with a history of symptomatic paroxysmal atrial fibrillation who failed guideline-directed medical treatment and cardioversion. Electrical mapping was attempted and complicated with catheter entrapping in the mitral valve (MV) apparatus, and multiple attempts for retrieval were unsuccessful and caused severe valvular dysfunction. Emergent valve replacement was required secondary to the extensive disruption of the valvular apparatus and posterior annulus. Mapping catheter entrapment in the valvular apparatus is an uncommon complication, but when it occurs, there is a high risk of injury to the MV apparatus during retrieval. To avoid extensive MV damage, operators should use minimal force during standard manoeuvres to extract the catheter. If gentle retrieval manoeuvres fail, surgical exploration and open retrieval may prevent MV damage. Early surgical consultation and exploration could result in open catheter retrieval or MV repair versus MV replacement.

Aortic valve implantation in the calf: a successful approach using Heartport cannulation and minimally invasive techniques.

BACKGROUND AND AIM OF THE STUDY: Aortic valve replacement (AVR) for mechanical prosthetic valvular testing has not been performed in calves because of anatomic difficulties, and sheep have traditionally been used in this situation. Hemodynamically, however, the calf constitutes an excellent model due to vigorous myocardial contractility, high stroke volumes and high cardiac output, and so has been used for preclinical evaluation of mechanical assist devices and mechanical valves in the mitral and tricuspid positions, which can be approached with relative surgical ease. Recently, a juvenile bovine model has been used to test a newly developed mechanical valve in the aortic position. METHODS: Ten calves (body weight 91+/-11 kg) underwent AVR with a 21-mm mechanical prosthesis via a small left intercostal thoracotomy with the aid of a Heartport cannulation device. A standard cardiopulmonary bypass (CPB) circuit was used. To circumvent the short bovine ascending aorta and to gain additional space to perform the aortotomy, two aortic cannulas were inserted for arterial-systemic perfusion. Nine calves each received a 21-mm experimental trileaflet aortic central flow valve prosthesis, and one calf received a 21-mm St. Jude Medical prosthesis. RESULTS: Mean CPB duration was 154.2+/-44.4 min, and mean ischemic time 80.1+/-15.9 min. Mean study duration was 42.6+/-53.7 days. Three calves were killed prematurely: two on days 2 and 7 due to complications arising from inadvertent entrapment of the right coronary artery ostium by a suture, and one on day 0 due to an accidental overdose of magnesium. Three calves, all of which had a first-version test valve, were killed electively due to valve malfunction secondary to early valvular thrombosis. Four animals (three with the final version valve and one with a standard valve as a control) survived until killed electively (range: 33-172 days). CONCLUSION: Results indicate that replacement of the native bovine aortic valve with a mechanical prosthesis can be performed safely in calves. Complication-free survival of up to six months can be achieved in the growing calf, provided that the test valve design satisfies minimum hemodynamic and coagulation criteria.