BackgroundBone wax is traditionally used as part of surgical procedures to prevent bleeding from exposed spongy bone. It is an effective hemostatic device which creates a physical barrier. Unfortunately it interferes with subsequent bone healing and increases the risk of infection in experimental studies. Recently, a water-soluble, synthetic, hemostatic compound (Ostene®) was introduced to serve the same purpose as bone wax without hampering bone healing. This study aims to compare sternal healing after application of either bone wax or Ostene®.MethodsTwenty-four pigs were randomized into one of three treatment groups: Ostene®, bone wax or no hemostatic treatment (control). Each animal was subjected to midline sternotomy. Either Ostene® or bone wax was applied to the spongy bone surfaces until local hemostasis was ensured. The control group received no hemostatic treatment. The wound was left open for 60 min before closing to simulate conditions alike those of cardiac surgery. All sterni were harvested 6 weeks after intervention.Bone density and the area of the bone defect were determined with peripheral quantitative CT-scanning; bone healing was displayed with plain X-ray and chronic inflammation was histologically assessed.ResultsBoth CT-scanning and plain X-ray disclosed that bone healing was significantly impaired in the bone wax group (p < 0.01) compared with the other two groups, and the former group had significantly more chronic inflammation (p < 0.01) than the two latter.ConclusionBone wax inhibits bone healing and induces chronic inflammation in a porcine model. Ostene® treated animals displayed bone healing characteristics and inflammatory reactions similar to those of the control group without application of a hemostatic agent.

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Background— The optimal surgical treatment in functional ischemic mitral regurgitation (FIMR) remains controversial. Recently, a posterior papillary muscle relocation (PMR) technique as adjunct procedure to ring annuloplasty has been proposed to prevent recurrent FIMR. In the present study, we used 3D cardiac MRI to assess the impact of relocating both papillary muscles as adjunct procedure to downsized ring annuloplasty on mitral leaflet coaptation geometry in FIMR pigs. Methods and Results— Eleven FIMR pigs were randomized to downsized ring annuloplasty (RA; n=6) or RA combined with PMR (RA+PMR, n=5). In the RA+PMR group, a 2–0 Gore-Tex suture was attached to each trigone, exteriorized through the corresponding papillary muscle, mounted on an epicardial pad, and tightened to relocate the myocardium adjacent to the anterior and posterior papillary muscles 5 and 15 mm, respectively. Using 3D MRI, the impact from these interventions on leaflet geometry was assessed. The distance from the posterior papillary muscle to the anterior trigone was reduced significantly more (median values) in the RA+PMR compared with RA animals at end-diastole (−7.9% versus 3.8%, P <0.01) and end-systole (−9.7% versus 2.5%, P =0.02). Accordingly, lateral tethering of the coaptation point (median values) was reduced significantly more in RA+PMR compared with RA animals (−42.8% versus −29.1%, P <0.01). Conclusions— Adding papillary muscle relocation to downsized ring annuloplasty reduced lateral leaflet tethering in a porcine experimental model of FIMR. Therefore, this technique holds promise for reducing persistent and recurrent FIMR in patients.

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The optimal surgical treatment in functional ischemic mitral regurgitation (FIMR) remains controversial. Recently, a posterior papillary muscle relocation (PMR) technique as adjunct procedure to ring annuloplasty has been proposed to prevent recurrent FIMR. We assessed the hypothesis that relocating both papillary muscles as adjunct procedure to down-sized ring annuloplasty improves mitral leaflet coaptation geometry in FIMR pigs. Eleven FIMR pigs were randomized to down-sized ring annuloplasty (RA, N=6) or RA combined with PMR (RA+PMR, N=5). In the RA+PMR group a 2– 0 Goretex suture was attached to each trigone, exteriorized through the corresponding papillary muscle, mounted on an epicardial pad and tightened to relocate the myocardium adjacent to the anterior and posterior papillary muscles 5 and 15 mm, respectively. Using 3D magnetic resonance imaging the impact from these interventions on leaflet geometry was assessed. Statistically significant (p<0.05) differences in postoperative leaflet geometry were observed at end-systole (RA vs. RA+PMR, mean ±SEM): Occlusional leaflet area (877 ±36 vs. 666 ±52 mm 2 ), tenting volume (1620 ±132 vs. 1064 ±198 mm 3 ), mean tenting height (5.9 ±0.2 vs. 4.9 ±0.3 mm), mean coaptation length (6.5 ±0.2 vs. 7.6 ±0.3 mm). Figure 1 shows coaptation length and tenting height of leaflet segments A1-P1, A2-P2 and A3-P3 at end-systole. Adding papillary muscle relocation to down-sized ring annuloplasty reduced leaflet tethering and improved coaptation geometry and therefore holds promise for reducing the prevalence of recurrent FIMR in patients.