Long-term follow-up of repair-like replacement of mitral valve using autologous pericardium.

Objectives: The present study assessed the late results of the operation, which consisted of the construction of a stentless mitral valve using autologous pericardium and valve implantation. Methods: Between 2011 and 2018, among 1617 consecutive patients who underwent mitral valve operation at our institution, 15 adult patients (0.9%) with unrepairable mitral valves who wished to avoid conventional mitral valve replacement underwent this operation. Ten patients (67%) had a history of valve repair. After discharge, patients were prospectively followed-up with a echocardiographic evaluation up to the end point. The mean follow-up term was 70.8 ± 42.5 months. Results: There were no hospital deaths or thromboembolic events and only 1 late noncardiac death. Intraoperative transesophageal echocardiography of all patients revealed no or trivial mitral regurgitation. Eight patients (53.3%) underwent redo valve replacement within 12 years. Except 1 late death, the postoperative course was divided into 3 groups depending on the occurrence of redo surgery, as follows: an early reoperation group (reoperation within 4 years; n = 4), a late reoperation group (reoperation after 4 years; n = 4), and a free from reoperation group (n = 6). The latest transthoracic echocardiographic examination performed 7.2 ± 2.9 years after the operation revealed the grade of mitral regurgitation to be none in 2 patients, mild in 2 patients, mild to moderate in 1 patients, and moderate in 1 patient in the free from reoperation group. Conclusions: Despite the high incidence of reoperation, Normo operation can be a viable option during valve replacement, especially for young patients.

Mitral valve repair for extreme billowing and prolapsing valve.

Objectives: We describe our method and results of mitral valve repair up to 20 years in a defined group of patients with mitral regurgitation caused by an extreme billowing and prolapsing valve. Methods: An extreme billowing and prolapsing valve was defined by the presence of excess tissue on both leaflets and prolapse of 2 or more of the 3 segments of each leaflet. Among 1344 consecutive patients who underwent mitral valve repair for degenerative mitral regurgitation between 1991 and 2012 at the Sakakibara Heart Institute, 73 patients met our definition of an extreme billowing and prolapsing valve. From these 73 patients, 67 patients who underwent mitral valve repair based on the surgical strategy we developed in July 1996 were enrolled in this study. Our strategy of mitral valve repair for extreme billowing and prolapsing valves consists of (1) volume reduction of the leaflets, (2) physiologic remodeling annuloplasty for long anterior leaflet, and (3) wide usage of artificial chordae. Results: Mean age of the patients was 46.6 ± 12.9 years. There were no hospital deaths and 6 late deaths in this series. Kaplan-Meier survival at 10 years was 96.8 ± 2.2%. There were 2 reoperations. Cumulative incidence rate of mitral valve reoperation and moderate or severe mitral regurgitation at 10 years was 1.8 ± 1.8% and 11.2 ± 4.0%. Number of artificial chordal replacement was associated with decreased risk of recurrent moderate mitral regurgitation (hazard ratio, 0.60; P = .03). Conclusions: Long-term echo follow-up demonstrates good results of mitral valve repair for extreme billowing and prolapsing valves using our strategy.

Anterior leaflet-oriented tricuspid annuloplasty using a flexible ring for severe tricuspid regurgitation.

We describe our concept and method of tricuspid annuloplasty using flexible ring for patients with severe tricuspid regurgitation accompanied by a severe tethering and a wide separation of the leaflets between the anterior leaflet and septal leaflet. The goal for our tricuspid ring annuloplasty using a flexible ring is to match the patient's own anterior leaflet configuration. We reduce the size of the tricuspid annulus respecting the individual configuration of the anterior leaflet to create a sufficient coaptation area of the leaflets. We performed this method in a 78-year-old female patient with very severe tricuspid regurgitation accompanied by a severe tethering. The anterior leaflet almost covered the orifice of the flexible ring during systole and intraoperative transesophageal echo examination revealed only trivial tricuspid regurgitation. We believe the anterior leaflet-oriented tricuspid ring annuloplasty using a flexible ring is useful for patients with severe TR accompanied by a severe tethering.

The efficacy of sinus plication in aortic valvuloplasty for bicuspid aortic valve: experiments in a pulsatile flow simulation model.

OBJECTIVES: Sinus plication has emerged as a promising tool that can lead to better stability in bicuspid aortic valve (BAV) repair. However, the mechanisms underlying the efficacy of this technique are unclear. We evaluated the hydrodynamic effect of sinus plication using the experimental pulsatile flow simulator and our original BAV model in vitro. METHODS: Based on the computed tomography data of a BAV patient who had undergone aortic valvuloplasty, a BAV model (group C, n = 6) was developed with bovine pericardium and vascular prosthesis (J-graft Shield Neo Valsalva 24 mm). We performed sinus plication (group SP, n = 6) in the BAV model and compared hydrodynamic data with the control model in the pulsatile flow simulator. Non-fused cusp angle, annulus diameter and effective height were measured by ultrasonography. RESULTS: The average flow was significantly increased in group SP compared to group C (4.24 ± 0.14 l/min vs 4.14 ± 0.15 l/min, respectively, P = 0.034). The mean transvalvular pressure gradient and regurgitant fraction were significantly decreased in group SP compared to group C (11.6 ± 4.3 mmHg vs 16.6 ± 5.0 mmHg, respectively, P = 0.009 and 14.1 ± 2.0% vs 17.4 ± 2.1%, respectively, P = 0.001). Ultrasound measurement indicated that non-fused cusp angle was significantly increased in group SP compared to group C (163.8° ± 9.2° vs 153.0° ± 4.6°, respectively, P = 0.012). CONCLUSIONS: Sinus plication in the BAV model significantly increased the commissural angle. It was effective in not only controlling regurgitation but also improving valve opening. These finding should be confirmed by evaluating cusp stress and/or long-term durability in the future studies.

Aortic root geometry following valve-sparing root replacement with reimplantation or remodeling: experimental investigation under static continuous pressure.

The differences in aortic root geometry associated with various valve-sparing root replacement (VSRR) techniques have not fully been understood. We evaluated the root configuration of current VSRR techniques by developing in vitro test apparatus. Six fresh porcine hearts were used for each model. The aortic root remodeling control group involved replacement of the ascending aorta with diameter reduction of sino-tubular junction (STJ) (C1). The aortic valve reimplantation control group involved replacement of the ascending aorta alone (C2). VSRR included remodeling without (RM) or with annuloplasty (RM + A) and reimplantation with a tube (RI) or a handmade neo-Valsalva graft (RI + V). The root geometry of each model in response to closing hydraulic pressures of 80 and 120 mmHg was investigated using echocardiography. Among the VSRR models, RM yielded the largest aorto-ventricular junction (AVJ), which was similar to those in non-VSRR models [mean AVJ diameter (mm) at 80 mmHg; RM = 25.1 ± 1.5, RM + A = 20.9 ± 0.7, RI = 20.7 ± 0.9, RI + V = 20.8 ± 0.4]. RI + V yielded the largest Valsalva size and largest ratio of Valsalva/AVJ, which was similar to the control group [mean Valsalva diameter (mm) at 80 mmHg; RM = 28.4 ± 1.4, RM + A = 25.8 ± 1.3, RI = 23.6 ± 1.0, RI + V = 30.5 ± 0.8, ratio of Valsalva/AVJ at 80 mmHg; RM = 1.14 ± 0.06, RM + A = 1.24 ± 0.06, RI = 1.15 ± 0.06, RI + V = 1.47 ± 0.05]. The STJ diameter at 80 mmHg was numerically smaller with RM + A (22.4 ± 1.2 mm) than with RM (24.8 ± 2.3 mm, p = 0.11). There were no significant differences in AVJ, Valsalva, or STJ distensibility or ellipticity between procedures. Current modifications, including annuloplasty for remodeling or reimplantation in the setting of neo-Valsalva graft, yield near-physiological root geometries.

Management of systolic anterior motion of the mitral valve: a mechanism-based approach.

Although the mechanism of systolic anterior motion (SAM) of the mitral valve is unknown, it is known to have a multifactorial pathophysiology. Echocardiographic analysis of the mitral leaflet revealed the step-wise progression of SAM, and intraventricular flow analysis revealed the contribution of drag force generated by the misled flow below the posterior leaflet. Although several diverse clinical features of SAM are already known, some key features need to be abstracted from among them to understand the regulation of SAM establishment. This paper reviews past articles that have investigated the mechanism of SAM and proposes a mechanism-based concept to provide insights for better comprehension of SAM recognition.

Causes of repair failure for degenerative mitral valve disease and reoperation outcomes.

OBJECTIVES: This study aimed to evaluate the causes of initial mitral valve (MV) repair failure, the details of reoperation and the long-term outcomes of mitral valve re-repair (Re-MVP). METHODS: We retrospectively reviewed 86 patients who underwent reoperation after MV repair for MR due to degenerative disease from October 1991 to December 2015. First, we analysed the initial MV repair data, causes of MV repair failure, reoperation data and long-term outcomes including survival. Second, the patients were classified into 2 groups based on valve related failure or procedure related failure , and the differences between the groups were analysed. RESULTS: Leaflet prolapse at the initial operation affected the bilateral leaflets in 37 (43%) patients, the anterior leaflet in 30 (35%) patients and the posterior leaftlet in 19 (22%) patients. Median duration from first operation to reoperation was 47.5 (interquartile range 4.8-85.8) months. Reoperation indication included recurrent mitral regurgitation alone in 59 patients, haemolysis combined with recurrent mitral regurgitation in 15 patients, infectious endocarditis combined with recurrent mitral regurgitation in 8 patients, mitral stenosis in 2 patients and left ventricular pseudoaneurysm in 2 patients. The cause of MV repair failure was valve-related in 61 (71%) patients, procedure-related in 20 (23%) patients and both in 5 (6%) patients. Re-MVP was successful in 23 (27%) patients. Re-MVP was more common in patients with procedure-related failure, which occurred earlier than valve-related failure. Freedom from all-cause death was significantly better after Re-MVP. The 5-year freedom from reoperation after Re-MVP was 95.7%. CONCLUSIONS: Re-MVP was more common in patients with procedure-related failure, which occurred earlier than valve-related failure. Durability of re-repaired MVs and survival of re-repaired patients were acceptable.

Early Clinical Outcome of Mitral Valve Replacement Using a Newly Designed Stentless Mitral Valve for Failure of Initial Mitral Valve Repair.

Here we report the early outcome of mitral valve replacement using a newly designed stentless mitral valve for failure of initial mitral valve repair. Mitral valve plasty (MVP) for mitral regurgitation is currently a standard technique performed worldwide. However, whether mitral valve repair should be performed for patients with advanced leaflet damage or complicated pathology remains controversial. Mitral valve replacement might be feasible for patients who have undergone failed initial MVP; however, it is not an optimal treatment because of poor valve durability and the need for anticoagulative therapy. We report two cases of successful mitral valve replacement using a newly designed stentless mitral valve made of fresh autologous pericardium, which may have a potential benefit over mitral valve repair or mitral valve replacement with a mechanical or bioprosthetic valve.

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.

Long-term outcomes of mitral valve repair for isolated commissural prolapse: up to 17-year experience.

BACKGROUND: Mitral valve repair has been shown to be effective for degenerative mitral regurgitation (MR). However, outcomes of mitral valve repair for commissural prolapse has not been well defined. Commissural prolapse has been often categorized into the groups of posterior leaflet prolapse or bileaflet prolapse, and outcomes and prognosis of isolated commissural prolapse has been rarely reported. We aimed to determine clinical and echocardiographic outcomes of mitral valve repair for isolated commissural lesion. METHODS: Between 1992 and 2010, 1,112 patients underwent mitral valve repair for degenerative MR at our institution. Among those, we reviewed 122 patients with isolated commissural prolapse. We analyzed operative outcomes, long-term survival rate, freedom from reoperation rate, and freedom from recurrent moderate or severe MR rate. RESULTS: The mean age was 57.0 ± 14.4 years old, 83 patients (68.0%) were men, 16 patients (13.1%) had infective endocarditis, 43 patients (35.2%) had atrial fibrillation, 27 patients (22.1%) had anterolateral commissural prolapse, 91 (74.6%) had posteromedial commissural prolapse, and 4 (3.3%) had bilateral commissural prolapse. We performed leaflet resection in 111 (91.0%) (concomitant sliding plasty in 43), chordal replacement in 94 (77.0%), and ring annuloplasty in 121 patients (99.2%). Residual mild MR was confirmed in 7 patients (5.7%) on predischarge echocardiography. No patients had moderate or severe MR at the time of discharge. Fifteen-year survival and freedom from mitral reoperation were 87.6% and 93.0%, respectively. Freedom from recurrent moderate or severe MR at 15 years was 87.4%. CONCLUSIONS: Mitral valve repair for isolated commissural prolapse demonstrated excellent early and late outcomes.

Long-term outcomes of artificial chordal replacement with tourniquet technique in mitral valve repair: a single-center experience of 700 cases.

OBJECTIVE: Artificial chordal replacement has been shown to be effective and durable, with numerous techniques reported. However, the outcomes of each technique have remained poorly defined. We report the long-term outcomes of the tourniquet technique. METHODS: We reviewed the data from 700 patients who had undergone mitral valve repair with the tourniquet technique from 1992 to 2010. We analyzed the operative outcomes, long-term survival rate, freedom from reoperation, and freedom from recurrent moderate or severe mitral regurgitation (MR). We also performed Cox regression analysis to explore the predictors of recurrent MR after mitral valve repair using the tourniquet technique. RESULTS: The mean age was 54.7±14.9 years; 212 patients (30.3%) had anterior leaflet prolapse, 142 (20.3%) had posterior leaflet prolapse, and 346 (49.4%) had bileaflet prolapse. Operative mortality was 1.3%. In 26 cases (3.7%), mitral valve repair was unsuccessful and was converted to replacement. Of those successfully repaired, the 12-year survival rate, freedom from mitral reoperation, freedom from recurrent moderate or severe MR, and freedom from recurrent leaflet prolapse was 85.9%, 88.7%, 72.3%, and 89.0%, respectively. The significant predictors of recurrent MR were anterior leaflet prolapse, age, New York Heart Association class III or IV, left ventricular end-systolic dimension, no annuloplasty ring or band, and postoperative residual mild or greater MR. CONCLUSIONS: The tourniquet technique is a simple and effective method to repair leaflet prolapse, with a low incidence of recurrent prolapse. The incidence of recurrent MR was high in the anterior leaflet prolapse group. Age, no annuloplasty ring or band, and residual MR were strong predictors of recurrent MR.

Post-repair coaptation length and durability of mitral valve repair for posterior mitral valve prolapse.

OBJECTIVE: Chordal placement with no or minimal leaflet resection has been suggested as the preferred technique for mitral valve repair for posterior leaflet prolapse, because it creates a longer coaptation zone. However, whether or not a long coaptation zone improves the durability of mitral valve repairs remains unclear. METHODS: We reviewed 119 patients with chronic degenerative mitral regurgitation including posterior middle scallop prolapse who underwent mitral valve repair between June 2004 and July 2008. We divided them into two groups according to post-repair coaptation length ≥8 mm (group A) or <8 mm (group B). We assessed whether coaptation length is associated with recurrent mitral regurgitation at 1 year after surgery and increase in the regurgitant jet area over 1 year. RESULTS: The group A had a lower incidence of recurrent mitral regurgitation (4.7 vs 9.2%, p = 0.30), smaller increase in mitral regurgitant jet area over 1 year (0.29 vs 0.40 cm(2), p = 0.43), and higher 5-year freedom from recurrent mitral regurgitation (85.6 vs 76.1%, p = 0.76), although the differences were not statistically significant. The multivariate analysis showed that large coaptation length tends to be associated with decreased recurrent mitral regurgitation at 1 year (odds ratio 0.02, 95% confidence interval 0.00-3.67, p = 0.14). CONCLUSIONS: This study did not confirm the association between coaptation length and durability of mitral valve repair for posterior middle scallop prolapse. However, there was a trend towards decreased recurrent mitral regurgitation with larger coaptation length.

Long-term outcomes of early surgery for asymptomatic severe chronic mitral regurgitation.

BACKGROUND AND AIM OF THE STUDY: The long-term outcomes of early surgery in patients with asymptomatic severe chronic mitral regurgitation (MR) and the impact of preoperative left ventricular dysfunction, atrial fibrillation (AF) and/or pulmonary hypertension (PH) on outcomes in this patient group, were evaluated. METHODS: Between 1992 and 2007, a total of 212 patients (mean age 50 +/- 15 years) with asymptomatic severe chronic degenerative MR underwent early mitral valve surgery within 12 months after echocardiographic diagnosis at the authors' institution. Mitral valve repair was attempted in all cases. The mean follow up period was 82 +/- 36 months. The patients were allocated to two groups; 111 with preoperative left ventricular dysfunction, AF and/or PH (group A), and 101 patients without those findings (group B). The outcomes were compared using univariate and multivariate analyses. RESULTS: Mitral valve repair was performed successfully in 211 patients (99.5%). The operative mortality was 0.5% (1/212). The 10-year actuarial survivals were 97.3% in all patients, 95.1% in group A, and 100% in group B. The 10-year cardiac adverse event-free rates (cardiac death, mitral valve reoperation or readmission with congestive heart failure) were 94.7% in all patients, 92.7% in group A, and 96.2% in group B. The seven-year freedom rates from recurrent MR were 93.1% in all patients, 90.0% in group A, and 97.0% in group B. In comparative analyses, group A had poorer late outcomes than group B, although the differences were not statistically significant. The multivariate analysis failed to show that preoperative left ventricular dysfunction, AF and/or PH were significantly associated with late cardiac adverse event (HR: 2.1, 95% CI: 0.4 to 10.8; p = 0.392). CONCLUSION: Early surgery for asymptomatic chronic MR demonstrated excellent early and late outcomes. The study results failed to confirm that preoperative left ventricular dysfunction, AF and/or PH were significantly associated with adverse outcomes of early mitral valve surgery in this patient group.

[Re-do mitral valve repair].

We describe proper indication and results of re-do mitral valve (MV) repair for recurrence of mitral regurgitation( MR) after MV repair. Among 1,163 patients who received MV repair for MV prolapsed between October 1991 and December 2010, 70 patients (6.0%) underwent redo MV operation. Only 14 patients (20%) among them received re-do MV repair and other 56 patients( 80%) underwent MV replacement. One patients of the 7 patients( 50%) who received re-do MV repair in 3 months after the operation received mitral valve replacement( MVR) for recurrence of MR 2 months after re-repair. However, in other 6 patients, postoperative echodoppler study performed after discharge revealed none or only trivial MR. In 6 of 7 patients, the cause of recurrence was detachment of the sutureline and hemolysis was present in 5 patients. Re-do repair was considered good indication for those patients who showed recurrence MR due to localize detachment of the sutureline. On the other hand, predictability of the results of re-do repair for chronic recurrent MR was low. Our newly developed stentless MV (Normo) would be a good solution for those patients who showed recurrence of MR after MV repair having low fesibility of re-do MV repair.

Do semi-rigid prosthetic rings affect left ventricular function after mitral valve repair?

BACKGROUND: After reports of cardiac impairment caused by mitral annuloplasty with rigid rings, several prosthetic rings with semi-rigidity were introduced. The influence of semi-rigid rings on postoperative cardiac function remains unknown. This study compared postoperative cardiac function between patients receiving a semi-rigid prosthetic ring and those receiving a flexible ring or band. METHODS AND RESULTS: Transthoracic echocardiographic data of 305 patients who underwent mitral valve repair for degenerative mitral regurgitation (227 patients receiving a semi-rigid ring and 78 receiving a flexible ring or band) were retrospectively reviewed. The imbalance in the preoperative characteristics between groups was adjusted with propensity score matching. Left ventricular ejection fraction, end-diastolic dimension, and end-systolic dimension were compared at 1 week, 6 months, and 1 year after surgery. Propensity score matching yielded 68 matched pairs of patients for whom there were few group differences in preoperative covariates. Between patients receiving a semi-rigid ring and those receiving a flexible ring or band in the propensity-matched cohorts, there were no significant differences in ejection fraction (P=0.322), end-diastolic dimension (P=0.576), or end-systolic dimension (P=0.567). CONCLUSIONS: There was little difference in the influence on postoperative cardiac function between semi-rigid rings and flexible rings or bands.

Influence of left ventricular function on development of systolic anterior motion after mitral valve repair.

OBJECTIVE: A hyperkinetic heart has been suggested as a risk factor for systolic anterior motion (SAM) after mitral valve repair, but the influence of preoperative left ventricular (LV) function on the development of SAM has not been elucidated. METHODS: Transthoracic echocardiographic data were retrospectively reviewed in 441 patients who underwent mitral valve repair for degenerative mitral regurgitation. Comparisons were made between patients with and without SAM (SAM cases vs noncases). RESULTS: The incidence of SAM was 6.1% (27/441). There were no differences in preoperative characteristics and operative procedures between the 2 groups except the prevalence of Barlow disease. The SAM cases exhibited a higher preoperative ejection fraction (EF) (SAM cases, 70.0% ± 7.1%; noncases, 65.1% ± 6.9%; P < .01) and smaller preoperative systolic LV end-systolic dimension (LVDs) (32.0 ± 5.4 mm vs 35.4 ± 5.7 mm; P = .02) than the noncases. The incidence of SAM was significantly associated with greater preoperative EF (P < .01 for trend) and reduced LVDs (P < .01 for trend). SAM did not occur in patients with an impaired (EF < 60%) or enlarged (LVDs > 45 mm) LV. The incidence of SAM was highest among patients with a small hyperkinetic heart. CONCLUSIONS: The study indicates that the development of SAM after mitral valve repair is associated with preoperative LV function. A small hyperkinetic heart is considered a risk factor for SAM and should be treated with caution.

Morphological analysis of systolic anterior motion after mitral valve repair.

OBJECTIVES: The systolic anterior motion (SAM) of mitral valves occurs at a certain rate despite the introduction of several preventive procedures. The purpose of this study was to investigate its mechanism by analysing the change in mitral valve morphology associated with operative procedures. METHODS: Components of mitral valves were measured before and after operative procedures by transoesophageal echocardiography in 179 patients who underwent mitral valve repair. Comparisons were made between 15 patients with SAM (SAM group) and 164 patients without SAM (non-SAM group). RESULTS: Morphological analysis in all the studied patients revealed that operative procedures shifted the coaptation point towards the left ventricular outflow tract by 6.9 mm and increased the extra portion of anterior leaflet that extended beyond the coaptation point by 5.4 mm. These changes were enhanced in the SAM group. Intergroup comparison revealed that there were no differences in the preoperative mitral valve morphologies between the two groups. After operative procedures, however, the SAM group showed smaller annular diameter and smaller coapted anterior/posterior length ratio compared with the non-SAM group. CONCLUSIONS: The results of this study show that operative procedures might modify the morphology of mitral valves susceptible to developing SAM. Postoperative smaller annular diameter and anterior shift of coaptation point were considered to contribute to the development of SAM.

Assessment of a novel stentless mitral valve using a pulsatile mitral valve simulator.

BACKGROUND AND AIM OF THE STUDY: The study aim was to develop a novel stentless mitral valve (SMV) and to evaluate its performance, using an original pulsatile simulator developed specifically to analyze the hydrodynamic function of the mitral valve. METHODS: The SMV developed at the authors' institution consists of two major components: a large anterior leaflet with commissures, and a small posterior leaflet. The valve is formed by suturing the leaflets (made from bovine pericardium) to a flexible (Duran) ring. The SMV, constructed with a 27 mm flexible ring, was installed into the mitral valve simulator, after which the four papillary flaps of the two leaflets were sutured to artificial papillary muscles. The artificial ventricle was driven pneumatically at a pulse rate of 70 beats/min, with a systolic fraction of 35%. The mean flow, aortic pressure, and atrial pressure were adjusted to 4.5 1/min, 120/80 mmHg, and 10 mmHg, respectively. A 27 mm mechanical valve (MEV; St. Jude Medical Inc.) was employed as a control. The hydrodynamic performance of the SMV and MEV were investigated and compared. An echo-Doppler study was also performed. RESULTS: The waveforms of the SMV and MEV showed a similar pattern. The mean transvalvular flow was 4.7 +/- 0.4 1/min for the SMV, and 3.55 +/- 0.13 1/min for the MEV (p < 0.001). Mitral regurgitation was 5.07 +/- 1.15 and 3.78 +/- 0.35 ml/beat, respectively (p < 0.05). Echocardiographic data indicated that the regurgitant jet towards the left atrial model was none or trivial for the SMV, and trivial for the MEV. CONCLUSION: Within the environment of the mitral valve simulator, the novel SMV prepared from bovine pericardium demonstrated excellent performance characteristics, and may represent a potential future alternative for bioprosthetic stented mitral valves.