Surgical techniques for the management of the 'hostile mitral annulus'.

The mitral annulus can be rendered hostile by several uncommon clinical situations such as infective endocarditis, calcification, or previous valve surgery. These can all lead to difficulties seating a prosthesis or annuloplasty ring. The posterior mitral annulus or anteriorly the intervalvar fibrous body can be affected. These situations continue to pose a formidable technical challenge to the cardiac surgeon in the operating room. We review the evidence around solutions for these problems with the intent of giving surgeons an overview of techniques to address these issues.

Mechanical circulatory support with the ABIOMED BVS 5000: the Toronto General Hospital experience.

BACKGROUND: Acute hemodynamic collapse resulting in cardiogenic shock and impending end-organ failure is usually associated with certain death. The introduction of short-term mechanical circulatory support (MCS) devices offers potential therapy to these critically ill patients. The BVS 5000 device (ABIOMED Inc, USA) is widely used in the United States, but rarely in Canada, where device reimbursement remains a barrier. OBJECTIVE: To present the Toronto General Hospital's (Toronto, Ontario) initial five-year experience with this device to highlight the indications for use, common complications and overall success rates. METHODS AND RESULTS: The institutional MCS database from 2001 to 2006 was reviewed, and 18 patients who received 30 devices in a variety of configurations were identified. The most common support configuration consisted of biventricular support (n=12), followed by isolated left ventricular support (n=4) and isolated right ventricular support in two recipients of an implantable long-term left ventricular assist device. Overall survival to device explant or transplant was 55% (n=10), of which five (50%) were successfully discharged from the hospital. The overall survival from device implant to hospital discharge was 28% (five of 18). The most common cause of death was multisystem organ failure. CONCLUSIONS: MCS with the ABIOMED BVS 5000 can successfully resuscitate critically ill patients; however, earlier institution of this device would avoid irreversible end-organ injury, and lead to higher rates of device explant and hospital discharge. Short-term MCS devices should be available in all cardiac surgical centres in Canada to permit stabilization and evaluation of the acutely ill cardiac patient and subsequent management in a heart transplant facility.

Mitral regurgitation due to myxomatous degeneration combined with bicuspid aortic valve disease is often due to prolapse of the anterior leaflet of the mitral valve.

BACKGROUND: This study examines the clinical, echocardiographic, surgical, and pathologic features of patients who had heart valve operations for combined congenital bicuspid aortic valve and mitral regurgitation due to degenerative disease of the mitral valve. METHODS: A retrospective review of 1595 patients who had procedures for mitral regurgitation due to degenerative disease of the mitral valve and 1820 patients who had procedures for congenital bicuspid aortic valve disclosed 29 patients who had combined diseases. RESULTS: The most common morphology of the bicuspid aortic valve was type 1 (fused right and left aortic cusps). Mitral regurgitation in 21 of 29 patients was caused by prolapse of the anterior leaflet, which was exceptionally large (mean height, 36.5 +/- 6.6 mm). Patients with prolapsed anterior leaflet of the mitral valve were younger (48 +/- 13 years vs 58 +/- 16 years, p = 0.01) and 95% were men. The bicuspid aortic valve was incompetent in 19 of 21, and the aortic annulus exceeded 30 mm in 20 of 21 patients. CONCLUSIONS: Patients with combined mitral regurgitation due to myxomatous degeneration and bicuspid aortic valve disease who require operations often have a large, prolapsing anterior leaflet of the mitral valve and dilated aortic annulus with aortic insufficiency due to cusp prolapse.

Ascending aortic aneurysms in unicommissural aortic valve disease.

BACKGROUND: Aneurysms of the ascending aorta occur as result of intrinsic changes in the aortic wall and have been well documented in patients with bicuspid aortic valve (BAV). In few reported clinical studies, documenting aneurysmal dilatation in unicommissural aortic valves (UAV); there have been no comments on the aortic wall pathology. This study presents the pathological findings of the ascending aorta in patients with UAV. MATERIALS AND METHODS: The clinical data from 39 patients with concomitant excision of the UAV and aneurysmal aortic tissue were reviewed. In all cases, the gross features of the valve and aortic segments were noted and submitted for histology. The sections of the aorta were semi-quantitatively graded for the extent of medionecrosis, cystic medial change, fibrosis, and elastic tissue changes (fragmentation/ loss) in the media. The medial alterations were correlated with patient age, gender, and valvular dysfunction, and compared to aneurysmal disease in BAV and three-cuspid aortic valves (TAV) excised over a 3-year period. RESULTS: Among 39 patients studied, a majority were males (92.3%), with a mean age at surgery of 39.92 years. Only three patients (7.69%) were above the age of 50 years. Eighteen patients (46.1%) had aortic stenosis with regurgitation. Ascending aorta diameters ranged from 4 to 5.5 cm. The overall pattern of medial changes was nearly the same in all cases of UAV, irrespective of age and nature of valvular dysfunction. Most cases showed mild histological changes, with medionecrosis and fibrosis being the more common and consistent features. However, varying grades of change affected different portions of the media and/or the aortic wall in the same patient. The changes in UAV aortae were comparable to the changes seen in the TAV and BAV, but these differed with the age of onset. CONCLUSIONS: This study demonstrates the presence of medial changes in the ascending aortic tissue in all patients of UAV with aneurysms. These changes, while mild to moderate in degree, likely have a similar pathogenetic mechanism as those seen in BAV disease. The significant difference in age, at the time of surgery, suggests a more rapid progression of the aortic changes.

Mitral valve repair for advanced myxomatous degeneration with posterior displacement of the mitral annulus.

OBJECTIVE: This study examines the outcomes of mitral valve repair in a defined group of patients with mitral regurgitation caused by advanced myxomatous degeneration. METHODS: Advanced myxomatous degeneration of the mitral valve was defined as a degenerative process whereby both leaflets are voluminous and aneurysmal and the mitral annulus diameter exceeds 40 mm and has posterior displacement, as determined by means of echocardiographic analysis. Over a 16-year period, we identified 183 patients who underwent valve repair in this subgroup of myxomatous degeneration. The repair consisted of relocating the posterior mitral annulus to the endocardium of the left ventricle at the atrioventricular junction, correction of leaflet prolapse, and annuloplasty. Analysis of perioperative variables and postoperative outcomes were undertaken. The mean follow-up was 5.9 +/- 4.2 years and complete. RESULTS: The patients' mean age was 52 years, and 118 were men. All patients had mitral regurgitation preoperatively. There were no early and only 8 late deaths (2 valve-related deaths). The survival at 10 years was 92% +/- 3%. Six patients required reoperation on the mitral valve, 5 for recurrent severe mitral regurgitation. The freedom from reoperation at 10 years was 93% +/- 3%. Six patients had severe and 21 had moderate mitral regurgitation. The freedom from recurrent moderate or severe mitral regurgitation at 10 years was 80% +/- 5%. We could not identify independent predictors of recurrent mitral regurgitation. CONCLUSIONS: Mitral valve repair for advanced myxomatous degeneration on the mitral valve provides excellent early functional results, but late recurrent regurgitation is common, despite correction of dilated and displaced mitral annulus and leaflet prolapse.