Background Annuloplasty ring dehiscence is a well described mechanism of mitral valve repair failure. Defining the mechanisms underlying dehiscence may facilitate its prevention. Methods Factors governing suture dehiscence were examined using an ovine model. Following undersized ring annuloplasty in live animals (N=5), Cyclic Force (FC) acting on sutures during cardiac contraction were measured using custom transducers. FC was measured at 10 suture positions, throughout cardiac cycles with peak left ventricular pressure (LVPmax) of 100, 125, and 150mmHg. Suture pullout testing was conducted on explanted mitral annuli (N=12) to determine suture holding strength at each position. Finally, relative collagen density differences at suture sites around the annulus were assessed by two-photon excitation fluoroscopy. Results Anterior FC exceeded posterior at each LVPmax (e.g. 2.8±1.3 vs. 1.8±1.2N at LVPmax=125mmHg, p<0.01). Anterior holding strength exceeded posterior (6.4±3.6 vs. 3.9±1.6N, p<0.0001). Based on FC at LVPmax=150mmHg, margin of safety before suture pullout was vastly higher between the trigones (exclusive) versus elsewhere (4.8±0.9 versus 1.9±0.5N, p<0.001). Margin of safety exhibited strong correlation to collagen density (R2=0.947). Conclusions Despite lower cyclic loading on posterior sutures, the weaker posterior mitral annular tissue creates higher risk of dehiscence, apparently due to reduced collagen content. Sutures placed atop the trigones are less secure than predicted, due to a combination of reduced collagen and higher overall rigidity in this region. These findings highlight the inter-trigonal tissue as the superior anchor, and have implications on the design and implantation techniques for next-generation mitral prostheses.

Purpose: Demonstrate the first use of a novel technology for quantifying suture forces on annuloplasty rings to better understand the mechanisms of ring dehiscence. Description: Force transducers were developed, attached to a size 24 Physio™ ring, and implanted in the mitral annulus of an ovine animal. Ring suture forces were measured after implantation and for cardiac cycles reaching peak left ventricular pressures (LVP) of 100, 125, and 150 mmHg. Evaluation: After implanting the undersized ring to the flaccid annulus, the mean suture force was 2.0±0.6 N. During cyclic contraction, anterior ring suture forces were greater than posterior ring suture forces at peak LVPs of 100 mmHg (4.9±2.0 N vs. 2.1±1.1 N), 125 mmHg (5.4±2.3 N vs. 2.3±1.2 N), and 150 mmHg (5.7±2.4 N vs. 2.4±1.1 N). The largest force was 7.4 N at 150 mmHg. Conclusions: Preliminary results demonstrate trends in annuloplasty suture forces and their variation with location and LVP. Future studies will significantly contribute to clinical knowledge by elucidating the mechanisms of ring dehiscence while improving annuloplasty ring design and surgical repair techniques.

Purpose: A mycotic aneurysm is an uncommon disease associated with a high mortality rate when managed surgically. This study reviewed our experiences in the surgical management of mycotic aortic aneurysms.Methods: In total, 26 patients who underwent surgery for a mycotic aneurysm were retrospectively reviewed. The mycotic aneurysms involved the thoracic aorta in 9 patients, the thoracoabdominal aorta in 4 patients, and the abdominal aorta in 13 patients. An overt aortic rupture in the mediastinum or retroperitoneal space was detected in 4 patients. Patients were classified into one of two groups, febrile or afebrile, and background characteristics, surgical intervention, and early and late mortalities were all compared.Results: There were 19 patients who underwent open surgery, and 7 patients underwent endovascular repair. No significant differences in the clinical characteristics were found between the two groups; however, the incidence of postoperative complications was significantly higher in the febrile group than in the afebrile group (P=0.024). Overall mortality was 15.4% (4/26), and 30-day mortality was 7.7% (2/26).Conclusion: Although febrile patients had a higher incidence of postoperative complications, surgical mortality from a mycotic aneurysm was within an acceptable range. Each patient should be thoroughly evaluated and treated on a case-by-case basis, using conventional open repair, endovascular repair, or a combination of both approaches.

Background Mitral valve (MV) repair using annuloplasty rings is the preferred method of treatment for MV regurgitation, but the impact of annuloplasty ring placement on LV intraventricular flow has not been studied. Methods Annuloplasty rings of varing sizes were placed in 5 healthy sheep (intercommissural ring size = 24, 26, 28, 30, and 32 mm) and 3D phase-contrast MRI (“4D flow MRI”) was performed prior to and one week after ring placement. Normal diastolic flow consisted of diastolic intraventricular vortices that naturally unwound during systole. Results Post-surgical intraventricular flow was highly disturbed in all sheep and the disturbance was greatest for undersized rings. Ring size was highly correlated with the diastolic inflow angle (Pearson’s r = −0.62, P < 0.1, CI (95%) = [−0.92 0.14]). There was a mean angle increase of mean diastolic inflow angle increase = 12.3° (< 30 mm, P < 0.01, CI (95%) = [4.8°, 19.6°]) for rings < 30 mm. There was an inverse relationship between peak velocity and annuloplasty ring area (Pearson’s r = −0.80, P < 0.05, CI (95%) = [−0.96 −0.2]. Transmitral pressure gradients increased significantly from baseline 0.73 +/− 0.18 mmHg to post-annuloplasty 2.31 +/− 1.04 mmHg (P < 0.05). Conclusions MV annuloplasty ring placement disturbs normal LV intraventricular flow patterns and the degree of disturbance is closed associated with annuloplasty ring size.

Objective: The aim of this study was to determine the impact of patient-prosthesis mismatch (PPM) after mitral valve replacement (MVR) on the late clinical outcome, evaluated from the referred value and measured mitral valve area in the echocardiograph. Patients and Method: The records of 212 patients who underwent MVR between 1995 and 2008 at Funabashi Municipal Medical Center, Japan were studied retrospectively. Exclusions were patients who had a repeat MVR or concomitant aortic valve surgery. Of 212 patients, 163 underwent the Doppler echocardiographic study more than 1 year after surgery. Primary endpoint was late survival, and secondary endpoint was major adverse cardiac event (MACE). The average follow-up period was 53.1 ± 100.8 months. The effective orifice area index (EOAI) was calculated using the referred effective orifice area (r-EOA) and measured effective orifice area (m-EOA). An EOAI smaller than 1.2 cm 2 /m 2 defined PPM. Results: For r-EOAI, 125 patients (group P) had PPM and 87patients (group N) did not. Between groups, there was a significant difference in the proportion of males (group P vs. N; 59% vs. 23%; P = 0.0001), postoperative NYHA class (1.02 ± 6.2 vs. 9.8 ± 1.6, P = 0.04), late mitral valve area (MVA) (2.50 ± 0.56 vs. 2.78 ± 0.60, P = 0.005), and peak transmitral pressure gradient (MPG) 11.9 ± 6.2 vs 9.8 ± 1.6, P = 0.04). However, there was no difference in late survival (P = 0.55) or incidence of a major cardiac adverse event (MACE) (P = 0.14). For m-EOAI, 17 patients (group P) had PPM and 146 patients (group N) did not. Between groups, there was a difference in the bioprosthetic valve (group P vs. N; 76% vs. 26%, P = 0.006) and mean MPG (5.2 ± 2.3 vs. 3.7 ± 1.8, P = 0.02). However, there was no difference in late survival (P = 0.99) and incidence of MACE (P = 0.86). The r-and m-EOAI were well correlated (correlation coefficient 0.46; 0.33-0.5) Conclusions: The PPM after MVR was not related to the late survival or the incidence of MACE based on both r-and m-EOAI. The patient group of PPM defined by r-EOAI tended to be male and that defined by m-EOAI tended to be bioprosthetic.