Sutureless mitral valve replacement with bioprostheses and Nitinol attachment rings: feasibility in acute pig experiments

Abstract

Objective: There is a need for fast, minimally invasive sutureless replacement of mitral valves.

Methods: Unchanged FDA-approved biological valve prostheses were sutured to Nitinol attachment rings (Endosmart, Stutensee, Germany) that were covered with textile (devices). The lower flange of the device was stretched in ice water and maintained in a stretched position with stretching sutures. In 9 acute pig experiments through a limited left thoracotomy, a single suture was placed around the mitral annulus, the device was positioned, the annular suture tied, the stretching sutures retracted, and the device activated by warm saline. Position of the device, heart and valve function, coronary arteries, left ventricular outflow tract, and surrounding structures were observed with transoesophageal echocardiography, left ventricular and coronary angiograms, and pathologic examination at autopsy.

Results: The devices could be easily navigated to the mitral valve annulus and actuated within seconds. Three devices were placed with warm blood in the operative field and were tilted or dislocated at autopsy. In the other 6 devices, transesophageal echocardiography and left ventricular and coronary angiography demonstrated normal prosthetic valve and heart function, without valvular or para-device leakage, and with normal aortic valve and coronary arteries. At autopsy in these 6 cases, the devices were strongly fixed at the anatomic mitral valve annulus, without abnormalities of the device, heart valve prosthesis, left ventricular outflow tract, or aortic valve ostium.

Conclusions: Nitinol attachments rings combined with unchanged biological valve prostheses can make fast and strong sutureless replacement of the mitral valve feasible in acute pig experiments. Applicators that constrain and release the device mechanically need to be developed.