Undersized Annuloplasty Research Articles

The Geoform Disease-Specific Annuloplasty System: A Finite Element Study

Functional mitral regurgitation (FMR) is the inability of mitral leaflets to coapt due to a combination of functional and geometrical factors. Valve competence is commonly restored by undersized annuloplasty, reducing the native annulus anteroposterior dimension. In case of severe FMR, this solution may be inadequate. The use of rings specific for the correction of FMR may lead to better results. The performance of the Geoform ring, a recently designed FMR-specific prosthesis, was compared with that of a standard Physio annuloplasty ring. Finite element modeling was used to simulate dilated cardiomyopathy-related FMR and compare, at the systolic peak, the valve's pathologic condition with the postoperative scenario corresponding to both devices. Three degrees of the pathology were simulated by progressively displacing papillary muscles apically, up to 5 mm. Three ring sizes were modeled. Regurgitant area, coaptation length, and stresses acting on valve structures were assessed. When the use of the Geoform was modeled, coaptation length was always longer than 7 mm. In the most unfavorable case, the regurgitant area reduction was 74% with respect to baseline, and leaflets stresses were reduced by 20% when undersizing was simulated. When Physio ring implantation was simulated, coaptation length maximum extent was equal to 4.3 mm, the maximum regurgitant area reduction was equal to 60%, and leaflet stress reduction was observed. Disease-specific prostheses may allow for restoration of valve competence even for significant degrees of leaflets tethering and avoid the need for aggressive undersizing, thus leading to more durable results.

Mitral valve repair in patients with cardiomyopathy

BACKGROUND: Mitral regurgitation (MR) is a frequent complication of end-stage-heart failure. These patients were either managed medically or with mitral valve replacement, both associated with poor outcome. Mitral valve repair with an undersized annuloplasty may improve survival and reduce the need for allografts. METHODS: Forty-one patients with an ejection fraction (EF) 2 underwent mitral valve annuloplasty using the Carpentier physio ring. RESULTS: Thirty day mortality was 12% (n = 5). Seven late mortalities were observed. The use of intra aortic balon pump (IABP) was necessary in seven patients. The 1, 2 and 5 year actuarial survival was 87%, 84% and 57% respectively. CONCLUSIONS: Mitral valve repair is a safe and effective operative intervention that corrects MR and offers a new strategy for patients with MR and end-stage-cardiomyopathy.

Is ischemic mitral regurgitation an indication for surgical repair or replacement?

Ischemic mitral regurgitation (IMR) is common in patients with coronary artery disease. While it is well-known that IMR exerts a graded effect upon survival-the greater the degree of IMR, the lower the survival-the indications for surgical treatment and the choice of surgical procedure (repair versus replacement) are controversial. In patients with mild to moderate IMR, the benefit of a mitral valve procedure has not been demonstrated, and surgical practice varies. In patients with severe IMR, mitral valve surgery is the norm, but guidelines for choosing between valve repair and valve replacement do not exist. Furthermore, the survival impact of mitral valve surgery in patients with severe IMR is uncertain. When patients with severe IMR undergo mitral valve surgery, undersized annuloplasty results in durable repair in 70% to 85% of cases. Newly-developed adjunctive repair techniques may further improve results. Currently, mitral valve repair is the procedure of choice in the majority of patients having surgery for severe IMR. However, the most severely ill patients and those with certain echocardiographic characteristics (e.g. severe bileaflet tethering) should be treated with bioprosthetic mitral valve replacement rather than repair.

Effects of Undersized Mitral Annuloplasty on Regional Transmural Left Ventricular Wall Strains and Wall Thickening Mechanisms

Undersized mitral annuloplasty, widely used for ischemic and functional mitral regurgitation (MR), has been proposed as an "annular solution to a ventricular problem." Beyond relief of MR, it is thought to improve global left ventricular (LV) shape, hence potentially reducing myocardial stress and promoting beneficial reverse LV remodeling. We previously observed that undersized annuloplasty inhibited systolic wall thickening at the LV base near the mitral annulus. In this study, we measured the effects of undersized annuloplasty on regional transmural LV wall fiber and sheet strains and wall thickening mechanisms. Nine sheep had transmural radiopaque beadsets surgically inserted into anterobasal and lateral equatorial LV regions, with additional markers silhouetting the LV and mitral annulus. 4-Dimensional marker dynamics were studied with biplane videofluoroscopy before and after tightening an adjustable Paneth-type mitral annuloplasty suture. Transmural circumferential, longitudinal, and radial systolic and remodeling strains in the subepicardium (20% depth), midwall (50%), and subendocardium (80%) in both regions were computed. Fiber and sheet angles from quantitative regional histology allowed transformation of these strains into local fiber (f), sheet (s), and sheet-normal (n) coordinates. Further analysis calculated the transmural contributions of sheet extension (E(ssc)), sheet thickening (E(nnc)), and sheet shear (E(snc)) to systolic wall thickening (E(33)). In the anterobasal region, undersized annuloplasty reduced systolic wall thickening (E33) by &50% at all transmural depths by inhibiting: (1) subendocardial systolic fiber shortening (-0.10+/-0.05 versus -0.04+/-0.05; P<0.05); (2) subepicardial (0.16+/-0.15 versus 0.09+/-0.08; P<0.05) and subendocardial (0.45+/-0.40 versus 0.19+/-0.18; P<0.05) systolic sheet thickening; (3) midwall sheet extension (0.22+/-0.12 versus 0.11+/-0.06; P<0.05); and (4) transmural sheet shear (subepicardium, -0.14+/-0.07 versus -0.08+/-0.07; midwall, 0.21+/-0.12 versus 0.10+/-0.11; subendocardium, -0.19+/-0.23 versus -0.11+/-0.16; P<0.05). In the remote lateral equatorial region, fiber-sheet strains and E33 were unchanged. In this acute animal study, undersized annuloplasty inhibited systolic wall thickening in the anterobasal region by reducing subendocardial systolic fiber shortening and laminar sheet wall thickening, but had no effects in a more distant LV region. This suggests that undersized mitral annuloplasty may have potentially deleterious effects on local myocardial mechanics.

Mitral Valve Repair for Functional Mitral Regurgitation in End-Stage Dilated Cardiomyopathy

The aim of this study was to assess the results of mitral valve (MV) repair in functional mitral regurgitation because of end-stage dilated cardiomyopathy (DCM). Seventy-seven patients with end-stage idiopathic (26 patients) or ischemic (51 patients) DCM underwent MV repair for functional mitral regurgitation (3 to 4+/4+). Fifty-eight patients (75.3%) were in New York Heart Association class III, and 19 (24.6%) were in IV. In 23 patients (29.8%) with a coaptation depth <1 cm, an isolated undersized annuloplasty was used. In the remaining 54 (70.1%), with a coaptation depth > or =1 cm, the "edge-to-edge" technique was associated with the annuloplasty. In most of the cases (88.3%), a complete rigid/semirigid ring was used. Concomitant coronary artery bypass graft was performed in 39 patients (50.6%). Hospital mortality was 3.8% (3 of 77). Actuarial survival was 90.7+/-3.64%, and freedom from cardiac events was 81.8+/-7.96% at 2.7 years. At a mean follow-up of 18.4+/-9.8 months (range, 1 month to 5 years) New York Heart Association class improved from 3.4+/-0.4 to 1.4+/-0.6 (P<0.0001). Mitral repair failure (recurrence of MR > or =3+/4+) was documented in 7 patients (9%): 2 in the edge-to-edge (2 of 54, 3.7%) and 5 in the isolated annuloplasty group (5 of 23, 21.7%) (P=0.03). Freedom from repair failure at 1.5 years was 95.0+/-3.4% and 77+/-12.1%, respectively (P=0.04). The absence of the edge-to-edge was the only predictor of repair failure (P=0.03). When residual MR was absent or mild, a reverse left ventricular remodeling was clearly documented. In patients with end-stage DCM, MV repair is feasible with low hospital mortality and important symptomatic improvement. The association of the edge-to-edge technique to the undersized annuloplasty can significantly improve the durability of the repair.

Mitral Valve Repair in the Treatment of Heart Failure.

Heart failure continues to be one of the leading causes of hospitalizations and mortality in the United States. Mitral valve regurgitation in patients with heart failure is most often a functional abnormality and as such represents a different disease entity from other more common causes of regurgitation. In general, in patients with heart failure the mitral valve structure is normal; however, regurgitation is secondary to changes in left ventricular (LV) structure and function, including mitral annular dilatation and changes in LV geometry. Mitral regurgitation affects almost all patients with heart failure as a preterminal or terminal event, and carries a high morbidity and mortality. Medical management is limited to treatment with diuretics and afterload reduction. Unfortunately, once significant amounts of mitral regurgitation are manifest, medical treatment alone is generally associated with poor long-term survival and outcome. Surgical treatment by means of undersized annuloplasty type repairs has shown great promise, for preventing worsening heart failure and improving overall LV function.

Ischemic mitral regurgitation redux—To repair or to replace?

Ischemic mitral regurgitation redux—To repair or to replace?