Evaluation of microvessel density by computerised image analysis in human renal cell carcinoma

A high microvessel density is suspected to favour tumour progression and the occurrence of metastasis. To elucidate the significance of abundant vessels for the behaviour of human renal carcinomas, the microvessel density of 110 renal cell carcinomas was correlated to pT category, nuclear grade, proliferative activity, occurrence of metastasis and relapse-free survival interval. The microvessels were quantified using CD31 immunostaining of endothelial cells and computer-aided image analysis. The rules for reproducible microvessel counting, as defined by Weidner, were strictly observed. A statistically significant relationship between the microvessel density and nuclear grade, proliferative activity, occurrence of metastasis and relapse-free survival was found; only for tumour size could no such relation be seen. Perplexingly, there is a diminution of microvessel density in association with increasing nuclear grade, proliferative activity, relapse-free survival interval and frequency of metastasis. This finding is contradictory to the hypothesis that an increasing microvessel density indicates a worsening prognosis.     

Case Report: Circumferential Pulmonary Vein Mapping and Ablation in Focal Atrial Fibrillation: Single Catheter Technique

Background: Atrial fibrillation (AF) can be cured in a subgroup of patients performing catheter ablation and eliminate trigger arrhythmias mainly originating in the pulmonary veins (PV's). Case Report: This case report describes the use of a novel catheter design combining both, circumferential mapping and radiofrequency delivery capabilities to perform pulmonary vein ablation in patients with focal AF. It could be demonstrated that this catheter was able to eliminate pulmonary vein potentials in a single left atrial catheter technique without acute evidence for PV stenosis. In two PV's of a second patient, where the Helix catheter was placed in a very ostial position, it was not possible to completely eliminate the PV signal component of the ostial electrogram. Long-term follow-up with AF recurrence documentation will clarify whether ostial PV signal amplitude reduction may serve as an acceptable procedural endpoint. Conclusion: PV potential elimination is feasible using this novel catheter design; safety and long-term efficacy of this single catheter approach will be evaluated in a multicenter study (BITMAP study: Breakthrough and Isolation Trial: Mapping and Ablation of Pulmonary Veins).