Cleft closure and undersizing annuloplasty improve mitral repair in atrioventricular canal defects

Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0535, USA.
The Journal of thoracic and cardiovascular surgery (Impact Factor: 4.17). 12/2008; 136(5):1243-9. DOI: 10.1016/j.jtcvs.2008.05.043
Source: PubMed


Reoperation rates to correct left atrioventricular valve regurgitation after primary repair of atrioventricular canal defects remain relatively high. The causes of valvular regurgitation are likely multifactorial, and simple cleft closure is often insufficient to prevent recurrence.
To elucidate the mechanisms leading to regurgitation, we conducted hemodynamic studies using isolated native mitral valves. Anatomy of these valves was altered to mimic atrioventricular canal type valves and studied under pediatric hemodynamic conditions. The impact of subvalvular geometry, cleft closure, annular dilatation, and annular undersizing on regurgitation were investigated.
Papillary muscle position did not have a significant effect on regurgitation. Cleft closure had a significant impact on valvular competence, with reduction in regurgitation volume with increased cleft closure. Regurgitation volume decreased from 12.5 +/- 2.4 mL/beat for an open cleft to 4.9 +/- 1.9 mL/beat for a partially closed cleft and to 1.4 +/- 1.6 mL/beat when the cleft was completely closed. Annular dilatation had a significant impact on regurgitation even after cleft closure. A 40% increase in annular size increased regurgitation by 59% for a partially closed cleft and by 84% for a fully closed cleft. Reducing the annular size by 20% from the physiologic level decreased the regurgitation volume by 12% for a fully open cleft and by 58% for the partially closed cleft case.
Annular dilatation after primary repair has a potentially significant role in the recurrence of atrioventricular valve regurgitation. Reducing the annular size and restricting dilatation as an adjunct to cleft closure is a promising surgical approach in such valve anatomies.

Download full-text


Available from: Nikolay V Vasilyev,
  • [Show abstract] [Hide abstract]
    ABSTRACT: The solution of the planning/ design/ scheduling problem is limited by existing solution algorithms and computing resources. A combined planning/scheduling problem over an extended horizon of several months yields a formulation with thousands of variables. A natural approach presented earlier is to decompose the large problem into smaller ones, the solution of the decomposed problems constituting the solution to the original problem. The decomposition is however, a nontrivial task because of the global decision making process. Infeasibilities may arise at the lower stage since we have only considered the design/planning stage at a macroscopic level, therefore, a diagnostic formulation δRF is presented here. The power of the approach in identifying the infeasibilities and its use to solve the design problem is discussed in this paper. Illustrative examples for batch plant design are presented.
    Computers & Chemical Engineering 06/1995; 19(19):577-582. DOI:10.1016/0098-1354(95)87097-0 · 2.78 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: To summarize the experience of surgical treatments of partial atrioventricular septal defect in 60 patients. From April 1999 to April 2004, 60 patients of partial atrioventricular septal defect were operated. Fifty-eight patients were performed with suture of the cleft of mitral valve and the other 2 were given mitral valve replacement; For closure of primum ASD, 53 patients with pericardial patches and 7 with Dacron patches. Coronary sinus was baffled to left atrium with kirklin procedure in 35 cases and baffled to right atrium with McGoon procedure in other 25 cases. Correct the accompanying cardiac deformity at the same time. The hospital mortality was 3.3% (2/60) due to low cardic output syndrome. The incidence rate of complete atrioventricular block was 8.00% (2/ 35) in the group with Kirklin procedure and 6.06% (2/25) in the group with McGoon procedure. There was no statistical significance between the 2 groups (P > 0.05). The follow-up was from 1 month to 5 years, and there was no late death. All cardiac function were improved except middle mitral regurgitation in 1 patient. Reasonable operative design, refined procedures, avoiding damage to conducting bundles and proper perioperative management are the key points in improving theraeutic effect.
    Zhong nan da xue xue bao. Yi xue ban = Journal of Central South University. Medical sciences 06/2005; 30(3):328-30. DOI:10.3724/SP.J.1008.2010.00332
  • [Show abstract] [Hide abstract]
    ABSTRACT: The elucidation of structure-affinity relationships in EF-hand proteins requires a reliable assay of divalent ion affinity. In principle, isothermal titration calorimetry (ITC) should be capable of furnishing estimates for Ca2+- and Mg2+-binding constants in these systems. And because the method yields the binding enthalpy directly, ITC can provide a more detailed view of binding energetics than methods that rely on 45Ca2+ or fluorescent indicators. For several reasons, however, it is generally not possible to extract reliable binding parameters from single ITC experiments. Ca2+ affinity is often too high, and Mg2+ affinity is invariably too low. Moreover, least-squares minimization of multisite systems may not afford a unique fit because of strong parameter correlations. This chapter outlines a strategy for analyzing two-site systems that overcomes these obstacles. The method--which involves simultaneous, or global, least-squares analysis of direct and competitive ITC data--yields binding parameters for both Ca2+ and Mg2+. Application of the method is demonstrated for two systems. The S55D/E59D variant of rat alpha-parvalbumin, noteworthy for its elevated metal ion affinity, binds divalent ions noncooperatively and is amenable to analysis using an independent two-site model. On the other hand, Phl p 7, a pollen-specific EF-hand protein from timothy grass, binds Ca2+ with positive cooperativity. Divalent ion-binding data for the protein must be analyzed using a two-site Adair model.
    Methods in enzymology 02/2009; 455:259-97. DOI:10.1016/S0076-6879(08)04210-9 · 2.09 Impact Factor
Show more