Faculty Bibliography

Degenerative mitral valve (MV) disease is the most common cause of organic mitral regurgitation (MR) in developed countries. Surgical mitral valve repair is the gold standard treatment for primary MR. Surgical mitral valve repair is associated with excellent outcomes in terms of survival and freedom from recurrent MR. As well, innovations in surgical repair techniques, including thoracoscopically and robotically assisted approaches, further reduce morbidity. Emerging catheter-based therapies may also provide advantages in select patient groups. Although the outcomes following surgical mitral valve repair are well described in the literature, longitudinal follow-up is heterogenous. Indeed, longitudinal follow-up and long-term data are vital to better advise treatment and counsel patients.

Heart disease remains the leading cause of worldwide mortality. Although the last decades have broadened our understanding of the biology behind the pathologies of heart disease, ex vivo systems capable of mimicking disease progression and abnormal heart function using human cells remain elusive. In this contribution, an open-access electromechanical system (BEaTS-β) capable of mimicking the environment of cardiac disease is reported. BEaTS-β was designed using computer-aided modeling to combine tunable electrical stimulation and mechanical deformation of cells cultured on a flexible elastomer. To recapitulate the clinical scenario of a heart attack more closely, in designing BEaTS-β we considered a device capable to operate under hypoxic conditions. We tested human induced pluripotent stem cell-derived cardiomyocytes, fibroblasts, and coronary artery endothelial cells in our simulated myocardial infarction environment. Our results indicate that, under simulated myocardium infarction, there was a decrease in maturation of cardiomyocytes, and reduced survival of fibroblasts and coronary artery endothelial cells. The open access nature of BEaTS-β will allow for other investigators to use this platform to investigate cardiac cell biology or drug therapeutic efficacy in vitro under conditions that simulate arrhythmia and/or myocardial infarction.

OBJECTIVES/OBJECTIVE:Fibrin glue is used to reinforce anastomosis in aortic surgery. There has not yet been a consensus on how it should be applied optimally. This study aimed to define the optimal condition of applying fibrin glue. METHODS:In experiment 1, we determined the optimal condition for spraying fibrin glue using an expanded polytetrafluoroethylene graft within a needle hole. The length and area of the fibrin cap within the hole were measured. In experiment 2, methods for applying fibrinogen were assessed by comparing brushing and spraying. In experiment 3, swine aorta segments sutured with a Dacron graft were divided into the following three groups: nothing was applied; fibrinogen was sprayed and rubbed using brush. The aorta was clamped and blood was infused from an occlusion catheter inserted into the graft. The pressure at the first appearance of blood leak was recorded. RESULTS:In experiment 1, among the four groups divided by the pressure and distance of spraying, the fibrin cap area in the group with 0.075 MPa and 2-cm spray distance was significantly larger than that in the group with 0.15 MPa and 2 cm (P < 0.01). In experiment 2, the fibrin cap area in the brushing group was significantly larger than that in the spraying group (P < 0.05). In experiment 3, the capacity to resist endoluminal pressure was higher in the brushing and combined spraying group compared with that in the sequential combined spraying group (P < 0.01). CONCLUSIONS:The brush and spray methods showed excellent hemostatic outcomes.

Extraperitoneal approach is commonly employed for thoracoabdominal aortic repair via Stoney incision. It is supposedly rare to encounter abdominal visceral bleeding during that procedure. However, the spleen may spontaneously adhere to the adjacent peritoneum, which could induce incidental injury to the spleen by its anterior mobilization during extraperitoneal approach. Unless we bare its potential risk in mind, bleeding from the spleen may be overlooked, which results in hemodynamic deterioration. We have experienced 3 cases of splenic injury that necessitated hemostatic maneuvers for bleeding during and just after the thoracoabdominal aortic repair.

OBJECTIVES/OBJECTIVE:Stentless bioprosthetic valves provide hemodynamic advantages over stented valves as well as excellent durability. However, some primary tissue failures in bioprostheses have been reported. This study was conducted to evaluate the morphometrical and biomechanical properties of the stentless Medtronic Freestyle™ aortic root bioprosthesis, to identify any arising problem areas, and to speculate on a potential solution. METHODS:The three-dimensional heterogeneity of the stentless bioprosthesis wall was investigated using computed tomography. The ascending aorta and the right, left, and non-coronary sinuses of Valsalva were resected and examined by an indentation test to evaluate their biomechanical properties. RESULTS:The non-coronary sinus of Valsalva was significantly thinner than the right sinus of Valsalva (p < 0.01). Young's modulus, calculated as an indicator of elasticity, was significantly greater at the non-coronary sinus of Valsalva (430.7 ± 374.2 kPa) than at either the left (190.6 ± 70.6 kPa, p < 0.01) or right sinuses of Valsalva (240.0 ± 56.5 kPa, p < 0.05). CONCLUSIONS:Based on the morphometrical and biomechanical analyses of the stentless bioprosthesis, we demonstrated that there are differences in wall thickness and elasticity between each sinus of Valsalva. These differences suggest that the non-coronary sinus of Valsalva is the most vulnerable and at greater risk of tissue failure. The exclusion of the non-coronary sinus of Valsalva may be beneficial to mitigate the long-term risks of tissue failure in the stentless bioprosthesis.