In vivo assessment of novel stentless valve in the mitral position.

BACKGROUND: We conducted in vivo examinations of a newly designed stentless mitral valve (SMV), formed by suturing 2 leaflets with the "legs" serving as chorda tendinea, made from bovine pericardium, to a flexible ring. METHODS AND RESULTS: Seven pigs underwent implantation of the SMV constructed with a 23-mm (n=5) or 25-mm (n=2) Duran ring. Baseline echocardiography examinations were used to evaluate the annular anteroposterior diameter, and distance between the mitral annulus (MA) and papillary muscles (PMs) to determine SMV-leg length. After removing the native valve, the SMV-legs were fixed to the anterior and posterior PMs, followed by fixation of the ring to the native MA. Immediately after surgery, all animals presented none or trivial mitral regurgitation, with mean and peak trans-SMV pressure gradient values of 1.9±0.8 and 6.0±3.1 mmHg, respectively. The mean length of the SMV-leg was 19.4±3.9 mm, which correlated with the distance between anterior and posterior MA-PM (r=0.96 and 0.94, respectively, P<0.01 for both). The discrepancy between the anteroposterior diameter of the ring (outside diameter) and that of the native valve was 1.0±2.9 mm, which correlated with the trans-SMV pressure gradient (r=0.81, P=0.025). CONCLUSIONS: In our preliminary study, the SMV demonstrated excellent diastolic inflow dynamics and closing function in vivo. Preoperative precise assessment of MV configuration may serve as a basis for selection of appropriate ring size and SMV-leg length.

[Leaflet resection for the degenerative mitral valve regurgitation; early/long-term assessment].

Leaflet resection for posterior leaflet prolapse has been a standard repair procedure with good longterm durability. The aim of this study was to review our experience of mitral valve repair, in which resection of the anterior and/or posterior leaflets was performed. Between October 1991 and December 2010, 172 patients with degenerative mitral valve regurgitation underwent mitral valve reconstruction,including 98 patients with the posterior leaflet prolapse, 47 patients with the anterior leaflet prolapse, 17 patients with both leaflets and 10 patients with the commissure prolapse. Most patients in this study were supposed to be caused by fibroelastic deficiency and we have not experienced systolic anterior motion after repair. The mean follow-up period was 8.7 ± 5.5 years. The freedom from reoperation rates at 15 years in 88.7 ± 5.3% of the anterior leaflet procedure, 96.6 ± 2.5% of the posterior leaflet, and 100% of both leaflets. The results of resection of a diseased prolapsed mitral leaflet have been promising so far. However, reoperation was required in 7 patients (4.1%) and reoperation rate was higher in patients with anterior prolapse and longer follow-up will evaluate precisely be benefit.

Giant saccular aneurysm of coronary arteriovenous fistula to the main pulmonary artery: intraoperative assessment by using fluorescent imaging.

Coronary arteriovenous fistulas (CAF) and coronary artery aneurysms (CAA) are uncommon, but their detection has recently increased. In this case we succeeded in identifying the residual shunt flow by using an intraoperative fluorescence imaging technique with indocyanine green after surgical treatment. The photodynamic eye imaging system is based on fluorescence of indocyanine green. This is the first report to identify residual shunt flow with such a giant coronary aneurysm by using fluorescence imaging, and the result indicates that this technique is useful for acceptance as one of the examinations to evaluate CAAs. Furthermore, it may be useful for the detection of shunt cases, such as congenital heart disease.

Prevalence of pannus formation after aortic valve replacement: clinical aspects and surgical management.

Pannus formation after aortic valve replacement is not common, but obstruction due to chronic pannus is one of the most serious complications of valve replacement. The causes of pannus formation are still unknown and effective preventive methods have not been fully elucidated. We reviewed our clinical experience of all patients who underwent reoperation for prosthetic aortic valve obstruction due to pannus formation between 1973 and 2004. We compared the initial 18-year period of surgery, when the Björk-Shiley tilting-disk valve was used, and the subsequent 13-year period of surgery, when the St. Jude Medical valve was used. Seven of a total of 390 patients (1.8%) required reoperation for prosthetic aortic valve obstruction due to pannus formation. All seven patients were women; four patients underwent resection of the pannus and three patients needed replacement of the valve. The frequency of pannus formation in the early group was 2.4% (6/253), whereas it was 0.73% (1/137) in the late group (P < 0.05). Pannus was localized at the minor orifice of the Björk-Shiley valve in the early group and turbulent transvalvular blood flow was considered to be one of the important factors triggering its growth. We also consider that small bileaflet valves have the possibility of promoting pannus formation and that the implantation of a larger prosthesis can contribute to reducing the occurrence of pannus.

Long-term assessment of mitral valve reconstruction with resection of the leaflets: triangular and quadrangular resection.

BACKGROUND: The procedure of quadrangular resection and suture for prolapsed posterior leaflet of the mitral valve is a reliable and reproducible method that achieves excellent long-term results. However, triangular resection and suture of a prolapsed anterior leaflet is not widely supported and different techniques have been advocated. The aim of this study was to review our experience of mitral valve repair in which resection of the anterior and/or posterior leaflets was performed. METHODS: Between October 1991 and September 2003, 105 patients with mitral regurgitation underwent mitral valve reconstruction with leaflet resection, including 55 patients with quadrangular resection of the posterior leaflet (P), 32 patients with triangular resection of the anterior leaflet (A), and 18 patients with resection of both leaflets (A+P). RESULTS: The mean follow-up period was 63.6 (1 to 139) months. Reoperation was required in 2 patients, each after resection of the anterior or posterior leaflet. The freedom from reoperation rates at 10 years in 93% +/- 5% of patients after triangular resection of the anterior leaflet, 96% +/- 3% after quadrangular resection of the posterior leaflet, and 100% after resection of both leaflets. There were no significant differences of survival or risk of reoperation among these three groups. The postoperative mitral valve area was significantly smaller than the preoperative area in all three groups, but remained large enough (A: 2.84 +/- 1.07; P: 2.6 +/- 0.87; A+P: 3.09 +/- 1.20 cm2) for adequate valve function. CONCLUSIONS: Triangular resection of a prolapsed anterior mitral leaflet is a reliable, reproducible, and durable procedure, like quadrangular resection of a prolapsed posterior leaflet.