Vascular grafts (VGs) are medical devices intended to replace the function of a blood vessel. Available VGs in the market present low patency rates for small diameter applications setting the VG failure. This event arises from the inadequate response of the cells interacting with the biomaterial in the context of operative conditions generating chronic inflammation and a lack of regenerative signals where stenosis or aneurysms can occur. Tissue Engineered Vascular grafts (TEVGs) aim to induce the regeneration of the native vessel to overcome these limitations. Besides the biochemical stimuli, the biomaterial and the particular micro and macrostructure of the graft will determine the specific behavior under pulsatile pressure. The TEVG must support blood flow withstanding the exerted pressure, allowing the proper compliance required for the biomechanical stimulation needed for regeneration. Although the international standards outline the specific requirements to evaluate vascular grafts, the challenge remains in choosing the proper biomaterial and manufacturing TEVGs with good quality features to perform satisfactorily. In this review, we aim to recognize the best strategies to reach suitable mechanical properties in cell-free TEVGs according to the reported success of different approaches in clinical trials and pre-clinical trials.

Background Kommerell’s aneurysm is a saccular or fusiform dilatation found in 3–8% of Kommerell’s diverticulum cases. A non-dissecting rupture rate of 6% has been reported. If ruptured, emergent surgical correction is usually granted. However, evidence regarding the optimal surgical approach in this acute setting is scarce. In this case report series, we aim to describe our experience managing type-1 non-dissecting ruptured Kommerell's aneurysm with hybrid emergent surgical approaches. Cases presentation From January 2005 to December 2020, three cases of type-1 non-dissecting ruptured Kommerell's aneurysm requiring emergent surgical repair were identified. The mean age was 66.67 ± 7.76 years, and 3/3 were male. The most common symptoms were atypical chest pain, dyspnoea, and headache (2/3). The mean aneurysm’s diameter was 63.67 ± 5.69 mm. Frozen Elephant Trunk was the preferred surgical approach (2/3). The Non-Frozen Elephant Trunk patient underwent a hybrid procedure consisting of a supra-aortic debranching and a zone-2 stent-graft deployment. We found a mean clamp time of 140 ± 60.75 min, cardiac arrest time of 51.33 ± 3.06 min, and a hospital stay of 13.67 ± 5.51 days. The most common complications were surgical-site infection and shock (2/3). Only one patient died (1/3). Conclusion Evidence of management for non-dissecting ruptured Kommerell's aneurysms is scarce. Additional, robust, and more extensive studies are required. The selection of the appropriate surgical approach is challenging, and each patient should be individualized. Frozen Elephant Trunk was feasible for patients requiring emergent surgical repair in our centre. However, other hybrid or open procedures can be performed.

Background Kommerell's diverticulum is a rare developmental abnormality of the aorta, associated in 20–60% of the cases with an aberrant subclavian artery. A Kommerell’s aneurysm is a saccular or fusiform dilatation that can be found in 3–8% of Kommerell’s diverticulum cases. A non-dissecting rupture rate of 6% has been reported. Because the patient's life is at risk, emergent surgical correction is usually granted. Different surgical interventions have been proposed, including open, endovascular, or hybrid approaches. However, evidence regarding the optimal surgical approach in the acute setting is scarce. In this case series, we aim to describe our surgical experience in the management of type-1 non-dissecting ruptured Kommerell's aneurysm. Cases presentation: From January 2005 to December 2020, three cases of type-1 non-dissecting ruptured Kommerell's aneurysm requiring emergent surgical repair were identified. The mean age was 66.67 ± 7.76 years, and 3/3 were male. The most common symptoms were atypical chest pain, dyspnea, and headache (2/3). The most frequent comorbidity was hypertension (2/3). The mean aneurysm’s diameter was 63.67 ± 5.69 mm. Frozen Elephant Trunk was the preferred surgical approach (2/3). The Non-Frozen Elephant Trunk patient underwent a hybrid procedure consisting of a carotid-subclavian bypass and a zone-2 stent graft deployment. We found a mean clamp time of 140 ± 60.75 min, cardiac arrest time of 51.33 ± 3.06 min, and a hospital stay of 13.67 ± 5.51 days. The most common complications were surgical-site infection and shock (2/3). Only one patient died (1/3). Conclusion Evidence involving the accurate diagnosis, prevention, and management of type-1 non-dissecting ruptured Kommerell's aneurysms is scarce. Additional, robust, and more extensive studies are required. The selection of the appropriate surgical approach is challenging. In our experience, Frozen Elephant Trunk was feasible for patients requiring emergent surgical repair. However, other hybrid procedures can be performed.