RESUMO
Tissue engineering aims to overcome the current limitations of heart valves by providing a viable alternative using living tissue. Nevertheless, the valves constructed from either decellularized xenogeneic or purely biologic scaffolds are unable to withstand the hemodynamic loads, particularly in the left ventricle. To address this, we have been developing a hybrid tissue-engineered heart valve (H-TEHV) concept consisting of a nondegradable elastomeric scaffold enclosed in a valve-like living tissue constructed from autologous cells. We developed a 21 mm mitral valve scaffold for implantation in an ovine model. Smooth muscle cells/fibroblasts and endothelial cells were extracted, isolated, and expanded from the animal's jugular vein. Next, the scaffold underwent a sequential coating with the sorted cells mixed with collagen type I. The resulting H-TEHV was then implanted into the mitral position of the same sheep through open-heart surgery. Echocardiography scans following the procedure revealed an acceptable valve performance, with no signs of regurgitation. The valve orifice area, measured by planimetry, was 2.9 cm2, the ejection fraction reached 67%, and the mean transmitral pressure gradient was measured at 8.39 mmHg. The animal successfully recovered from anesthesia and was transferred to the vivarium. Upon autopsy, the examination confirmed the integrity of the H-TEHV, with no evidence of tissue dehiscence. The preliminary results from the animal implantation suggest the feasibility of the H-TEHV.
RESUMO
BACKGROUND: Aortic dissection is a relatively uncommon, but often catastrophic disease that requires early and accurate diagnosis. It often presents in patients with congenital connective tissue disorders. The current aortic surgical techniques are related with serious early and late complications. This case report emphasizes the importance of early diagnosis of aortic root dilatation and the risk of dissection, especially in patients with congenital connective tissue disorders. We present an alternative, contemporary and multidisciplinary approach based on the present state of knowledge. CASE PRESENTATION: We present a rare case of a young female patient with Loeys-Dietz syndrome who was admitted with an uncomplicated aortic dissection (Stanford type B / DeBakey type III) and a dilated aortic root. After a period of close surveillance and extensive vascular imaging, thoracic endovascular aortic repair was deemed to be technically not possible. Medical treatment was optimized and our patient successfully underwent a personalised external aortic root support procedure (PEARS) as a contemporary alternative to existing aortic root surgical techniques. CONCLUSIONS: This case highlights the importance of interdisciplinary approach, close follow-up and multimodality imaging. The decision to intervene in a chronic type B aortic dissection is still challenging and should be made in experienced centers by an interdisciplinary team. However, if an acute complication occurs, thoracic endovascular aortic repair TEVAR is the method of choice. In all cases optimal medical treatment is important. There is increasing evidence that personalized external aortic root support procedure PEARS is effective in stabilizing the aortic root and preventing its dilatation and dissection not only in patients with Marfan syndrome, but also in other cases of aortic root dilation of other etiologies. Moreover, many publications have reported the additional benefit of reduction or even eradication of aortic regurgitation by improving coaptation of the aortic valve leaflets in dilated aortas.