Case report Evidence of leaflet injury during percutaneous aortic valve deployment

Abstract It has been suggested that valved stent deployment during transcatheter aortic valve implantation may be responsible for traumatic injury to pericardial leaflets, especially with balloon expandable valved stents. However, such an injury has not been described nor reported so far. We here report the microscopic analysis of 4 Sapien-Edwards prostheses, 2 of which have been implanted in humans. There was no macroscopic evidence of traumatic injury to the pericardial leaflets of the percutaneous valves. However, pathological microscopic findings were observed in all of them. These mainly consisted of collagen fibers fragmentation and disruption. Areas of non-or mildly affected tissue were adjacent to areas of severely damaged tissue. The entire thickness of the leaflets might be involved. The severity of the lesions also differed among leaflets from a same prosthesis. Areas of plasmatic insudation were identified in one case. The disruption index was significantly higher in the Sapien group in comparison to the control group: 42.4% (14-63.5%) versus 17.5% (9.2-31%) ( p < 0.001). Although of limited size sample, this study does prove that traumatic injury to leaflets occurs during percutaneous valves implantation. This should prompt physicians to wait for the long-term results of this new technology before extending the indications to low-risk patients.

The induction of heme oxygenase 1 decreases contractility in human internal thoracic artery and radial artery grafts

ObjectiveSpasm remains a potential problem encountered during the use of arterial grafts in coronary artery bypass surgery. Heme oxygenase plays a role in the control of arterial vasoreactivity. Heme oxygenase exists in 2 constitutive isoforms (heme oxygenase 2 and 3) and an inducible isoform (heme oxygenase 1). The aim of our study was to induce heme oxygenase 1 by using hemin in human internal thoracic and radial arteries and to evaluate the effect of this induction on the contractility of these arterial grafts.MethodsSegments of human arterial grafts obtained from patients undergoing isolated coronary artery bypass surgery were incubated in organ chambers for 4 hours in the presence of 10−4 mol/L hemin. Concentration-response curves to norepinephrine were obtained in control and hemin-treated arterial rings. Heme oxygenase 1 expression was evaluated by using enzyme-linked immunosorbent assays and immunohistochemical staining.ResultsThe contractility of the arterial rings to norepinephrine was significantly reduced after incubation with hemin. Zinc protoporphyrin (an inhibitor of heme oxygenase) reversed the effect of hemin, whereas the inhibitor of nitric oxide synthase had no effect. The inhibitor of soluble guanylate cyclase blocked the decrease in contractility induced by hemin. Immunohistochemical staining revealed a large expression of heme oxygenase 1 in all vascular layers of hemin-treated internal thoracic artery and radial artery rings. Enzyme-linked immunosorbent assay studies showed a significant increase in heme oxygenase 1 levels in hemin-treated internal thoracic artery and radial artery rings.ConclusionHemin caused in vitro induction of heme oxygenase 1 in human internal thoracic artery and radial artery grafts. This induction resulted in a reduced contractility to norepinephrine, partially through the cyclic guanosine monophosphate–dependent pathway. This effect was independent from nitric oxide synthesis

Diagnostic de bicuspidie aortique chez les patients ayant une sténose aortique sévère (intérêt du doppler couleur en échocardiographie transoesophagienne multiplan)

PARIS6-Bibl. St Antoine CHU (751122104) / SudocSudocFranceF