Tex Heart Inst J. 2006; 33(1): 54–56.

Detachment of the Mitral Valve Anterior Leaflet as a Complication of Aortic Valve Replacement

Fatih Islamoglu, MD, Anil Ziya Apaydin, MD, Kenan Degirmenciler, MD, Cemil Gurgun, MD, and Isa Durmaz, MD

Departments of Cardiovascular Surgery (Drs. Apaydin, Degirmenciler, Durmaz, and Islamoglu) and Cardiology (Dr. Gurgun), Ege University Medical Faculty, 35100 Izmir, Turkey

Abstract

Mitral regurgitation after aortic valve replacement is generally reported as a complication of a Manouguian's procedure for annulus enlargement. However, even if no annular enlargement procedure is performed, this complication may be encountered after isolated aortic valve replacement because of either extensive decalcification of the aortic annulus or progressive tension on the anterior leaflet of the mitral valve, caused by aortic valve sutures placed adjacent to firm or heavily calcified valve tissue. Routine transthoracic echocardiography may be inadequate for diagnosis of this condition; transesophageal echocardiography should be used both for preoperative diagnosis and for intraoperative management. We report the case of a patient who had severe mitral regurgitation that occurred after aortic valve replacement with a mechanical valve.

Keywords: Aortic Valve/Surgery, Procedures/Methods, Echocardiography, Transesophageal, Esophageal, Mitral Valve Insufficiency/Etiology/Ultrasonography/Surgery, Postoperative Complications

Mitral regurgitation after aortic valve replacement (AVR) is usually reported as a rare and late complication of a Manouguian's procedure for annulus enlargement.1 However, even if an annular enlargement procedure has not been performed, extensive decalcification of the aortic annulus might pose hazards to neighboring structures, such as disruption of the fibrous continuity between the aortic and mitral annuli, the mitral anterior leaflet, and the interventricular septum. Another danger is the exertion of progressive tension on the anterior leaflet of the mitral valve, caused by aortic valve sutures placed adjacent to firm or heavily calcified valve tissue. Herein, we report the case of a patient who had severe mitral regurgitation that occurred after aortic valve replacement with a mechanical valve.

Case Report

In September 2004, a 47-year-old man came to our institution with dyspnea upon exertion, fatigue, and excessive perspiration. He had undergone AVR with a 21-mm bileaflet mechanical prosthesis (St. Jude Medical, Inc.; St. Paul, Minn) 5 months earlier. The AVR had been performed through a median sternotomy at another hospital. Medical records describing the previous procedure indicated that AVR had been necessary in this patient because of severe aortic regurgitation with calcification. A permanent pacemaker had been implanted 2 weeks after AVR because of complete atrioventricular block. Approximately 3 weeks after surgery, the patient had experienced dyspnea and other progressive symptoms of left-sided heart failure. He was being treated with digoxin, diuretics, and warfarin. Although echocardiographic evaluation had shown a dysfunctional aortic prosthesis with aortic perivalvular leak, no surgical repair had been attempted.

When the patient came to our clinic, his permanent pacemaker rhythm was 80 beats/min, and his systemic blood pressure was 120/70 mmHg. On cardiac auscultation, a systolic murmur with a mid-diastolic rumble at the apex was detected. Two-dimensional transthoracic echocardiography (TTE) showed a dysfunctional aortic prosthesis, moderate aortic valve regurgitation, an aortic perivalvular leak, and severe mitral valve regurgitation (MR). The left atrial diameter (42 mm) and the left ventricular end-diastolic diameter (54 mm) approached the upper limits of normal; the left ventricular end-systolic diameter (29 mm) was normal. Because the previous echocardiographic evaluation had documented no MR, transesophageal echocardiography (TEE) was performed. This study showed a dysfunctional aortic prosthesis with a perivalvular leak and a fistulous track on the anterior annulus of the mitral valve; there was an associated jet flow of 500 cm/sec from the left ventricular outflow to the left atrium through the mitral valve (Fig. 1). Chest radiography showed mild right pleural effusion.

The erythrocyte sedimentation rate, C-reactive protein concentration, and white blood cell count were within normal limits; these findings excluded low-grade infection as the cause of annular detachment. Because MR is often accompanied by considerable hemolysis, that possibility was tested and was supported by laboratory results: the patient's serum lactate dehydrogenase (LDH) level (1,815 U/L) was quite high, and his hemoglobin concentration was low (8.9 g/dL).

The patient underwent surgery for repair of the aortic perivalvular leak and correction of MR. The chest was entered through a median sternotomy. Dense adhesions were released in order to separate the anterior wall of the heart from the sternum. Heparin was administered; then the right femoral artery was dissected and cannulated. Double venous cannulation from the right atrium was performed. A cannula for retrograde cardioplegia was placed in the coronary sinus, and a vent cannula was placed in the right superior pulmonary vein. After the distal ascending aorta had been clamped, a transverse aortotomy incision was made on the line of the previous incision. The aortic prosthesis was inspected, and no functional abnormality was found.

The mitral valve was examined by use of a superior approach through the roof of the left atrium. With slight retraction, the mitral valve was easily visible. A tear, approximately 3 cm long, was detected on the mitral valve, between the anterior leaflet and the annulus, adjacent to the commissure of the left coronary and noncoronary cusps of the excised aortic valve. This defect was closed by approximating the separated edges of the anterior leaflet and annulus with 3 pledgeted 4-0 polypropylene sutures. Care was taken to avoid pleating or purse-stringing of the valve tissue when the sutures were tied (Fig. 2). Although examination of the aortic valve prosthesis revealed no perivalvular leak caused by suture detachment, one 4-0 pledgeted polypropylene suture was placed through the aortotomy to reinforce the implantation line at the level of the commissure between the left coronary cusp and the noncoronary cusp.

After de-airing, the left atrium and the aorta were closed with 4-0 polypropylene continuous running sutures. The cross-clamp was removed, and TEE was performed during a brief period of weaning from cardiopulmonary bypass (CPB). This examination showed that regurgitant jet flow persisted near the posteromedial commissure of the mitral valve, although the flow was less than that previously measured. Therefore, full CPB was re-established, and the aorta was re-clamped.

The left atrium was again entered by the superior approach, and 1 additional 4-0 polypropylene pledgeted suture was placed at the separated leaflet --annulus junction near the posteromedial commissure of the mitral valve, as indicated by TEE. The atriotomy was again closed by continuous suturing with 4-0 polypropylene. The patient was rewarmed and weaned from CPB with inotropic support. Another TEE showed no regurgitant jet on the mitral valve. The overall pump time was 235 minutes; the cross-clamp time was 138 minutes.

The patient's pacemaker was in ventricular pacing mode (VVI) with a rhythm of 80 beats/min; his hemodynamic status progressively improved during the postoperative period. All inotropic support was discontinued on postoperative day 2. The patient's postoperative recovery was uneventful. He was discharged from the hospital on postoperative day 15. A postoperative TTE at the time of discharge showed a satisfactory repair with clinically insignificant MR and a normally functioning aortic prosthesis with a mean transaortic gradient of 13 mmHg (Fig. 3). Five weeks postoperatively, the patient's serum LDH level (280 U/L) and hemoglobin concentration (12.1 g/dL) were within normal limits; no hemolysis was indicated. Six months after surgery, the patient had no symptoms and no MR. The aortic prosthesis was functioning well. He was seen again 15 months postoperatively and was still in good condition.

Discussion

Clinically significant MR resulting from mitral valve prolapse is relatively common among patients who have undergone Manouguian's procedure with a prosthetic patch. However, we found no published report of severe MR caused by traumatic disruption of the mitral annulus and the anterior leaflet after AVR without annular enlargement. The absence of such a report may be due to the rarity of this complication. Findings of MR in association with Manouguian's procedure indicate that the complication often occurs during the late postoperative stages as the result of patch degeneration rather than an inappropriate incision.1 --3 We found only 1 case in which a traumatic tear in the mitral anterior leaflet was detected as a complication of Manouguian's procedure.4

Although our patient had not undergone aortic root enlargement, detachment of the mitral anterior leaflet from the annulus most likely occurred because of extensive decalcification performed during excision of the aortic valve. Because the fibrous continuity between the aortic and mitral annuli remained intact, one might speculate that this tear did not occur during the procedure but rather developed over time because of progressive tension on the leaflet from the aortic valve sutures adjacent to firm, heavily calcified valve tissue.

We observed that routine TTE was inadequate for diagnosis. Therefore, we recommend the use of TEE for determining the definitive cause of severe MR after AVR. Transesophageal echocardiography is valuable not only for preoperative diagnosis but also for intraoperative management of such cases.

Different surgical approaches, including the superior,5 biatrial,6 and transatrial superior approaches,7 have been recommended for reoperation on the mitral valve. We used a superior approach combined with aortotomy, which provided ease of access and optimal visibility.

The possibility of mitral leaflet detachment from the annulus should be considered in patients who have extensive annular calcification and MR after AVR. Close follow-up, early diagnosis with TEE, and intraoperative use of TEE to determine the completeness of surgical repair may lead to an uneventful recovery in such patients.

Footnotes

Address for reprints: Fatih Islamoglu, MD, Ege Universitesi Tip Fakultesi, Kalp ve Damar Cerrahisi Anabilim Dali, 35100 Izmir, Turkey

E-mail: fislam@med.ege.edu.tr

References
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Figures and Tables
figure 13FF1
Fig. 1 Preoperative transesophageal echocardiography image (apical 2-chamber view) shows severe regurgitant jet flow directed from the left ventricular outflow tract to the left atrium through the mitral valve.
figure 13FF2
Fig. 2 Repair of the defect has been accomplished by approximating the separated edges of the anterior leaflet and annulus with pledgeted 4-0 polypropylene sutures. Care was taken to avoid pleating or purse-stringing of the valve tissue when the sutures (more ...)
figure 13FF3
Fig. 3 Postoperative transthoracic echocardiogram (parasternal long-axis view) shows the absence of clinically significant mitral regurgitation.