In vivo mechanical properties of thoracic aortic aneurysmal wall estimated from in vitro biaxial tensile test.

To investigate the mechanism of aneurysm rupture, it is necessary to examine the mechanical properties of aneurysm tissues in vivo. A new approach to evaluate in vivo mechanical properties of aortic aneurysmal tissues has been proposed in this study. The shape of the aneurysm was modeled as a sphere, and equi-biaxial stress in the in vivo state was estimated from the diameter and the wall thickness of each aneurysm and mean blood pressure of each patient. The mechanical properties of the aneurysm at the in vivo stress were estimated from its in vitro biaxial tensile properties. There were no significant correlations among maximum diameter D, wall thickness t, and mean infinitesimal strain in the in vivo state epsilon(m). This indicates the wall deformation during aneurysm development was not elastic but plastic. The mean incremental elastic modulus H(m), an index of tissue stiffness, had a significant positive correlation with elastic modulus anisotropy index K(H). This indicates the aneurysmal wall got more anisotropic in vivo as it becomes stiffer.

Use of cuffed anastomosis in total aortic arch replacement.

The distal aortic anastomosis portion of the total arch surgery remains technically complex especially in cases in which an aortic arch aneurysm extends below level of carina. We present the cuffed anastomosis that overcomes this difficulty. We applied this technique in 49 patients of elective total aortic arch aneurysm repair using selective cerebral perfusion from 1996 to 2001. Hospital mortality was 2%.

Successful surgical treatment for impending rupture in acute type A dissecting aneurysm complicated with a thoracoabdominal aortic aneurysm in an octogenarian.

Emergency or urgent thoracoabdominal aortic replacement in octogenarians has high morbidity and mortality rates due to decrease in the potential of other organs because of their age and the high invasiveness. Here, report a case of an 81-year-old woman who was diagnosed as having an impending rupture in an acute type A dissecting aneurysm complicated with a thoracoabdominal aortic aneurysm, who was rescued successfully by replacement of the thoracoabdominal aorta, under epidural perfusion cooling.

Safety and clinical benefits of transsubxiphoidal left ventricular puncture.

We performed a transsubxiphoidal LV puncture (TSLVP) to evaluate left ventricular function in 21 patients with both mechanical prosthetic aortic and mitral valves and successfully obtained hemodynamic information on each patient. Analyzing cardiac hemodynamic information and ventriculographic findings obtained with TSLVP, we concluded that seven of the patients required repair of their prosthetic valves. Five of these seven patients agreed to replacement of their valves, whereas two did not. TSLVP was performed adequately and safely without severe complications, suggesting that this maneuver is easier than that of transapical LV puncture and should be recommended for the assessment of left ventricular hemodynamic functions instead of the transapical LV puncture, especially in patients requiring replacement of two valves.

Expression of the von Willebrand factor in atrial endocardium is increased in atrial fibrillation depending on the extent of structural remodeling.

BACKGROUND: The incidence of stroke in patients suffering atrial fibrillation (AF) is increased when left atrial enlargement occurs. Recently, the platelet adhesive molecule, von Willebrand factor (vWF), located in the atrial endocardium, has been shown to be increased in patients with a variety of heart diseases compared with patients who have no cardiac problems. METHODS AND RESULTS: We investigated the expression of vWF mRNA and protein in the endocardium as a possible prothrombotic alteration of AF in association with atrial structural remodeling. Atrial appendage specimens were obtained during either heart surgery or at an autopsy from AF patients with and without underlying heart disease. The immunohistochemical and in situ hybridization signals for vWF in the endocardium were well correlated and varied widely among the individual atrial appendages examined. The increased expression of vWF in the endocardium was associated with enlarged left atrial dimensions in mitral valvular disease or increased myocyte diameters in the underlying myocardium. Platelet adhesion/aggregation on the endocardium was always found under the fresh thrombi and was colocalized with strong vWF staining, but not necessarily with fibrinogen and/or fibrin staining. CONCLUSIONS: Endocardial overexpression of vWF may occur during the process of atrial structural remodeling contributing to the thrombotic predilection of AF in association with underlying heart disease.