Transcatheter aortic valve implantation: impact on clinical and valve-related outcomes

Severe aortic regurgitation after percutaneous transcatheter aortic valve implantation: on the importance to clarify the underlying pathophysiology

Severe symptomatic aortic stenosis in a 90-year-old man was treated with percutaneous aortic valve implantation (TAVI) with a 29-mm CoreValve Revalving system. Following implantation, severe aortic regurgitation occurred. Echocardiography showed a small paravalvular and a huge valvular leakage, probably due to one malfunctioning valve leaflet. Concerning this pathophysiology, a further TAVI was performed using a second 29-mm CoreValve Revalving system, as a "valve-in-valve" implantation.

Transcatheter aortic valve implantation: review of the nature, management, and avoidance of procedural complications

Transcatheter aortic valve implantation (TAVI) is becoming a reality in the management of patients with severe aortic stenosis and high or prohibitive risk for standard surgical management. Current understanding of the potential adverse events associated with this procedure is limited. Risks associated with TAVI differ from those related to surgical valve replacement and include vascular injury; stroke; cardiac injury such as heart block, coronary obstruction, and cardiac perforation; paravalvular leak; and valve misplacement. The clinical experience of multiple centers experience with different valve implantation systems and techniques was reviewed. Awareness of how complications occur might help in their avoidance, recognition, and management. Ultimately, improved understanding of the potential complications associated with TAVI might help improve outcomes and allow wider application of this therapy.

Olfactory ensheathing cell phenotype following implantation in the lesioned spinal cord

Although olfactory ensheathing cells (OECs) are used to promote repair in the injured spinal cord, little is known of their phenotype in this environment. In this study, using quantitative reverse transcriptase-polymerase chain reaction RT-PCR, expression of neuregulin-1 mitogen/survival factors and the axonal growth regulator Nogo was quantified in OECs and compared with other non-neuronal cells. Their expression was also compared with OECs which had previously been encapsulated in a porous polymer tube and implanted into the injured spinal cord. Similar to astrocytes and fibroblasts, OECs expressed various neuregulin subtypes including neu differentiation factor, glial growth factor and sensory and motorneuron-derived factor. Implanted OECs upregulated neu differentiation factor and secreted neuregulin, but downregulated expression of all other variants. OECs and oligodendrocytes expressed Nogo-A, -B and -ABC and were immunopositive for Nogo-A protein. The Nogo-A protein in OECs was found to be cytoplasmic rather than nuclear or cell surface associated. Unlike oligodendrocytes, OECs expressed Nogo-66 receptor (NgR) mRNA. Implanted OECs upregulated Nogo-A and -B, but downregulated Nogo-ABC and NgR.