1. Intra-ventricular Papillary Muscle Head Approximation is Effective in Treating Ischemic MR in Dilated Ventricles - Comparison with Ring annuloplasty Muralidhar Padala PhD, Weiwei Shi MD PhD, Rajnish Duara MS MCh, Kanika Kalra MBBS, Apoorva Girish MBBS, Vinod H. Thourani MD, Robert A. Guyton MD, Eric L. Sarin MD Muralidhar Padala PhD, Weiwei Shi MD PhD, Rajnish Duara MS MCh, Kanika Kalra MBBS, Apoorva Girish MBBS, Vinod H. Thourani MD, Robert A. Guyton MD, Eric L. Sarin MD Structural Heart Research & Innovation Laboratory Division of Cardiothoracic Surgery Emory University 4.28.2015 spadala@emory.edu 95 th Annual Meeting of the American Association of Thoracic Surgeons Structural Heart Research & Innovation Laboratory Division of Cardiothoracic Surgery Emory University 4.28.2015 spadala@emory.edu 95 th Annual Meeting of the American Association of Thoracic Surgeons

2. Disclosures Funding sources: American Heart Association Scientist Development Grant Carlyle Fraser Heart Center at Emory University Financial Relationships: Vinod Thourani MD Edwards Lifesciences St. Jude Medical, Maquet Abbott Vascular Apica Cardiovascular Sorin Biomedical Robert Guyton MD Medtronic

3. Introduction: Ischemic MR Ischemic MR increases morbidity and mortality, and its timely and durable repair is necessary to preserve cardiac function Grigioni, JACC, 2005 Calafiore, MMCTS, 2005

4. Introduction: Undersizing Annuloplasty Undersizing ring annuloplasty is the current repair of choice, but is associated with early recurrent MR

5. Introduction: Post-ring persistent MR Padala M, JHVD, 2014 Undersized ring annuloplasty draws the posterior annulus anteriorly and the chordal insertions away from the PM tips APM tip PPM tip

6. Higher inter-PM distance in IMR patients further exacerbates the tethering imposed by the undersizing ring Kalra K, JACC, 2014 Introduction: Post-ring persistent MR

7. HYPOTHESIS: Reducing the inter-papillary muscle distance by approximating the papillary muscle heads will relieve leaflet edge tethering and improve leaflet coaptation with or without annuloplasty APM head PPM head APM head PPM head Pledgeted head approximating suture Hypothesis: PM head approximating suture Hypothesis: PM head approximating suture

8. In adult Yorkshire swine (30-35 kg) the left circumflex branches perfusing the postero-lateral wall and the muscle were percutaneously occluded Methods: Swine model of IMR

9. PHASE 1 (N=6) PHASE 2 (N = 25) Repair 1 (N=6) Papillary Muscle Approximation [ PMA ] v v Repair 2 (N=7) Undersizing annuloplasty ring [ Ring ] Repair 3 (N=12) Combination [ PMA + Ring ] Methods: Experimental Design

10. Results: Measured Indices Echo derived measurements at 3 time-points [PRE]Pre-operative [ 8-10 weeks post MI] [POST] Acutely post repair [FU]Chronic follow-up [ 8-12 weeks post repair] TA ant TA pos TH S-P AD CL S-PAD : Septal-lateral annular diameter TA ant, TH, TA pos : Leaflet tenting characteristics CL: Coaptation length

11. Result 1: Annular Dimensions Mitral annular size continued to increase post-repair in PMA only group, and was restricted by the ring in other groups S-P AD

12. Result 2: Tenting Height Tenting height was significantly reduced by PMA only or ring with PMA. Ring only did not reduce the tenting height TH

13. Result 2: Tenting Area Posterior and anterior tenting areas were significantly reduced with PMA, but sustained when only the ring was used for repair TA ant TA pos

14. Result 3: Coaptation & Mobility Significant increase in coaptation length was achieved with all repairs but ring with PMA was highest CL

15. A computational model was used to model the effect of each repair on the leaflet and chordal stress distribution Result 4: Valve Stress Distribution PMA Ring PMA + Ring

16. COMMENT 1.In this swine model, papillary muscle approximation improved leaflet coaptation by reducing the tethering on the leaflets. 2.Concomitant with ring annuloplasty, papillary muscle tip approximation had the largest coaptation length and least tenting area. 3.Favorable coaptation geometry with PM approximation reduced leaflet and chordal stresses

18. Result 4: Transmitral Gradient

19. LIMITATIONS 1.Head vs. partial vs. full papillary muscle approximation remains to be compared in the model 1.Impact of progressive LV dilatation on PMA without a ring needs longer term assessment 1.Need to investigate the changes in mitral regurgitant jet characteristics after the repair