Background and aim of the study: Valve repair is currently performed to treat mitral regurgitation, but aortic valve repair remains a surgical challenge. In contrast, aortic valve replacement leads to complications and constraints on the patients' quality of life and valve durability. The mechanisms that produce malcoaptation of the aortic leaflets, with resultant insufficiency, are mainly due to prolapse or retraction of the leaflets. Thus, a new strategy has been proposed to correct valvular insufficiency, using magnetic force.
Methods: Low-profile permanent magnets were implanted in seven sheep, under cardiopulmonary bypass (CPB), through a transverse aortotomy, and maintained in place for three months. No aortic insufficiency was created in these first experiments. Two-dimensional color Doppler echocardiography was used to assess the function and safeguarding of the aortic valve. Blood samples were withdrawn to assess hemolysis, and histopathologic examinations performed at necropsy.
Results: Direct implantation of the three permanent magnets was possible in all seven animals, but the surgical procedure resulted in major complications in three cases. Only five animals could be weaned from CPB, and only four survived the procedure at three months. One magnet was also shown to have migrated postoperatively. Echocardiography confirmed the stability of the aortic leaflet contours. The biocompatibility of the implanted magnets (i.e., absence of hemolytic reaction) was found to be satisfactory, without a need for postoperative anticoagulation.
Conclusion: The use of magnetic force to correct valvular insufficiency has not previously been reported, and is an interesting field of investigation. Whilst these experiments are at an early stage of development, future changes in magnet design and surgical approach are indicated.