Geometry and fusion of aortic valves from pulsatile flow ventricular assist device patients.

BACKGROUND AND AIM OF THE STUDY: Aortic valve commissural fusion is a process in which fibrous tissue is deposited at the aortic valve commissures, creating adhesion between leaflets and preventing opening. Fusion has recently been associated with the implantation of left ventricular assist devices (VADs), affecting upwards of 50% of patients in recent studies. Aortic incompetence has also been associated with pulsatile VAD use, but a specific structural mechanism has not been identified. The study aim was to measure aortic valve geometry and fusion in tissue samples from explanted hearts of VAD recipients and to identify features that might explain the development of aortic valve dysfunction. METHODS: The diameter, perimeter and thickness of the aortic root, as well as the height, edge length and thickness of each of the three aortic leaflets were measured in seven valves. Histological studies were performed of both fused and unfused leaflets. RESULTS: The aortic root geometry showed an elliptical aorta, with asymmetric leaflets. The right coronary leaflet had the greatest edge length, but was thinnest. The other two leaflets were smaller, but slightly thicker. Overall, the aorta and valve geometry was within the normal range. Fusion was found in five of the seven valves studied, and often observed in multiple leaflets. Fusion length correlated loosely with the time of VAD support. Tissue from both fused and unfused valves showed unilateral fibrosis in the leaflets, and a loss of the laminar tissue structure that was related to the duration of VAD support. CONCLUSION: These findings support previous observations that pathological changes occur in the aortic valves of VAD patients shortly after implantation. While the tissue exhibits abnormalities in the structure, the geometry does not show gross remodeling such as annular dilatation or leaflet lengthening that might precede the development of aortic valve dysfunction. These changes are associated with the development of aortic valve fusion, and may be related to the biomechanical changes introduced by the VAD.

Gastrointestinal stromal tumor presenting as a pelvic mass.

Gastrointestinal stromal tumors (GISTs) are c-kit-positive tumors that may arise anywhere in the tubular gastrointestinal tract. Around 5% of the cases arise elsewhere in the abdominal cavity. Tumors originating in the omentum and mesentery have been reported.A 31-year-old woman presented with pelvic pain, a palpable pelvic mass, and elevated CA-125. Imaging showed innumerable pelvic and abdominal masses. Histopathology showed a GIST that was positive for c-kit and vimentin and negative for desmin and smooth muscle actin. The patient was started on imatinib mesylate. Six months after diagnosis the tumor has remained stable.GI stromal tumors (GIST) may initially present as pelvic mass with elevated CA-125. Imatinib mesylate is the current mainstay therapy for GISTs after surgery.