Description
The patient was a 40-year-old female with rheumatic mitral valve disease
and longstanding severe mitral stenosis. She reported significant
fatigue and NYHA class II dyspnea. She had undergone successful
percutaneous balloon commissuroplasty four years prior to this
presentation. Routine serial transthoracic echocardiograms (TTEs)
indicated progression of her disease. She had no other significant
medical history. Preoperative coronary angiography revealed normal
coronary arteries. The patient was scheduled for an outpatient mitral
valve replacement via midline sternotomy.
During the operation, the mitral valve was exposed through the
interatrial groove. The anterior leaflet was resected and annular
calcifications were debrided. The posterior leaflet was tacked to the
posterior annulus to maintain annulopapillary muscle continuity. The
annulus was sized for a 25/33 mm On-X MMV. Interrupted 2-0 pledgeted
sutures were used to sew the ring and after tying all the sutures, the
valve appeared to be well-seated. With the prosthesis positioned in the
anti-anatomical orientation, gentle probing of the occluders revealed
restricted opening. Their excursion appeared to be limited by remnants
of native tissue protruding below the level of the posterior annulus. A
decision was made to rotate the valve within its sewing ring into an
anatomic orientation. Both testing with the leaflet probe and initial
transesophageal echocardiogram (TEE) images obtained while weaning from
cardiopulmonary bypass (CBP) showed that the MMV was closing and opening
well. However, a repeat TEE done at the time of chest closure suggested
that while the anterior leaflet continued to move normally, the motion
of the posterior leaflet was now restricted, causing an incomplete
closure (Fig.1; Supplementary Video 1). The mean transvalvular pressure
gradient was still 2 mmHg and there was no regurgitant flow. At that
point, the patient was already decannulated. Therefore, we elected to
validate our suspicion using cinefluoroscopy. Findings on
cinefluoroscopy confirmed limited excursion of the posterior leaflet
(Fig.2; Supplementary Video 2) and the decision was made to reinstitute
CPB for valve repositioning.
On surgical re-inspection, the infra-annular tissue previously
protruding was no longer visible. It is likely that it became tucked
under the housing of the prosthesis with repeated ventricular filling
and expansion. This allowed us to rotate the prosthesis back to an
anti-anatomical orientation. Intraoperative TEE was reassuring and
showed normal movement of both occluders. The patient was discharged
from hospital after seven days. At the 3-month follow-up, she had made a
good recovery and an outpatient TTE showed normal MMV function with low
gradients.