A (relative) defeat

Let’s start with the most important thing: the patient is alive and well, hence  the word “relative”  mentioned in the title. This is  “just” about a “technical” defeat. A brief description of the case: patient with severe coronary artery disease and a severe mitral valve regurgitation with indication to  surgery (aortocoronary bypass with 4-5 grafts on all three main coronary artery  branches and mitral valve repair).

During surgery we acknowledge the mechanism of the mitral valve regurgitation as shown in the pre-operative three-dimensional echocardiography: a prolapse of two thirds of the vast posterior leaflet in its posteromedial part (P2 and P3) with rupture of one main chord.

As repair technique, a quadrangular resection followed by annuloplasty (implant of a prosthetic full ring) is chosen. The resection width is 15 mm. After completion of the implantation of the prosthetic ring, the hydrostatic probe (filling of the left ventricle with saline solution) shows an acceptable result. During weaning of the patient off cardiopulmonary bypass, intraoperative transesophageal ehocardiography (TEE) reveals a relevant residual mitral regurgitation due to an anteromedial prolaps of the rest of the P2 scalop (hence towards P1). Weaning is reversed, the aorta is cross-clamped again and cardiac arrest is induced by means of infusion of cardioplegic solution in the aortic root. Inspection of the valve confirms the TEE diagnosis. Obviously the prior quadrangular resection was not suficiently aggressive to eliminate all prolapsing valve tissue. The resection of P2 is widened. To recruit valve tissue and bridge the significant gap left over by the resection, a bidirectional sliding plasty (towards P1 and P3) is performed with a good anatomical result. The hydrostatic probe, however, shows a relevant regurgitation. It’s mechanism is almost an evergreen: due to the reduced height of the neo-posterior leaflet, the anterior leaflet slides over the posterior and prolapses, causing the regurgitation. This is corrected effectively by implanting an artificial chord (Goretex CV3 suture) at the prolapsing edge of the anterior leaflet, anchored at the anteromedial papillary muscle. Now the hydrostatic probe shows a satisfactory functional result. During reperfusion and weaning off cardiopulmonary bypass, an acceptable result is confirmed by means of TEE (residual regurgitation not more than light).

Towards the end of surgery (sternal closure) the anesthesist (operating the TEE) reported a significant change of the valve finding: suddenly the regurgitation became  at least moderate and the regurgitation morphology changed. After interdisciplinary consultation the unanimous decision was made to revise the valve. The patient was  put onto cardiopulmonary bypass again, the heart was arrested and the valve exposed again: a suture dehiscence caused by tissue ripping was noted at the base of the sliding plasty towards P1 of the repaired posterior leaflet.  Having considered the quality of the tissue, a third attempt to valve repair did not seem neither promising nor reasonable. The valve was therefore replaced with a biologic prosthesis, preserving the posterior leaflet and the subvalvular structures. Surgery ended with no further difficulty.

Replacing a regurgitant mitral valve, especially on the basis of the prolapse of the posterior leaflet only, is a defeat for a cardiac surgeon. These valves must be repaired with a 90% success rate. In the above case, notwithstanding the use of the whole range of valve repairing techniques and obtaining a good result, the tissue sagging caused the defeat.

From my point of view, it is important that among the possible causes we cannot identify a lack of technical skills, lack of compression of the underlying mechanisms of the specific case, inability to choose and apply the appropriate repair techniques, lack of fighting spirit and not having chosen the easy way out (of a replacement) from the beginning. A critical discussion on the assessment of the first quadrangular resection must, however, be accepted.

To sum up positively: in the unfortunate evolution of this case, we were lucky enough that the these events happened in the OR and not in the postoperative phase.