ECHOCARDIOGRAPHIC MONITORING OF MINIMALLY INVASIVE MITRAL-VALVE SURGERY USING AN ENDOAORTIC CLAMP

Background and aims of the study: Twenty-four patients underwent minim ally invasive mitral valve repair (n=16) or mitral valve replacement ( n=8) using the Port-Access system. Intraoperative transesophageal echo cardiography (TEE) was used in these patients to: (i) reassess valve p athology preoperatively; (ii) guide and continuously assess placement and position of the aortic endoclamp; (iii) measure aortic root diamet ers, aortic distensibility and aortic wall appearance prior to and aft er aortic endoclamping; (iv) evaluate the de-airing procedure; (v) eva luate the results of mitral valve repair; and (vi) guide weaning from cardiopulmonary bypass (CPB). Methods and results: Placement and posit ioning; of the endoclamp was guided effectively in all but one patient who had acute retrograde aortic dissection with the onset of femoro-f emoral bypass. The mean position of the tip of the endoclamp was 2.8+/ -0.5 cm from the aortic valve annulus. The position was stable in all but five patients in whom repositioning and additional clamp volume we re required. There was only a poor relationship between balloon volume and sinotubular junction diameter. The dynamic movement of the aorta was well preserved after clamping and the elasticity module did not ch ange significantly (1.6+/-0.71 vs. 1.5+/-0.75 dynesx10(6)/cm(2)). No i ntimal tears or wall edema was observed after clamp release. De-airing was incomplete in five patients, two of whom had transient ST-elevati ons with regional wall motion abnormalities, Weaning of CPB was theref ore postponed until the ECG had normalized. All mitral valve repairs b ut one were successful (equal to or less than grade I residual mitral insufficiency). One patient with persistent grade II mitral insufficie ncy underwent valve replacement using the same approach. Conclusions: TEE can effectively guide minimally invasive mitral valve surgery usin g the Port-Access system. Placement and positioning of the endoclamp a nd its effects on the aortic wall can be evaluated. De-airzing, weanin g from CPB and the results of the procedure were effectively monitored using TEE.