The 21st Annual Meeting of the American Venous Forum (February 11-14) maintained the high standard of scientific excellence in the field of venous disease research. There were 33 plenary presentations, eight debates, seven mini-presentations and numerous workshops and symposia. The “Great Debates” were part of the post-graduate symposium organized by our current president, Joe Caprini. The debates covered a wide variety of topics and encouraged the audience to participate. Of the 33 plenary presentations, all of which were excellent, five deserve a special mention.
Dr. David Wright, chief scientific officer from BTG PLC, presented the first paper. It was entitled “Is there a relationship between varicose veins and patent foramen ovale (PFO)?” The investigators examined the prevalence of right to left cardiac shunts and the incidence of High Intensity Signals (HITS) observed in the middle cerebral artery after endovenous microfoam embolization (EMA) in 217 patients. The investigators observed a 39.2% of right to left shunting at rest. Shunting increased to 59% with a valsalva maneuver. HITS occurred in 83.6% of patients receiving EMA. The study indicated that the incidence of PFOs in the general population is much greater than the previously reported incidence of 27%. This paper emphasizes the need for vigilance and clinical observation of patients during and after the instillation of foam sclerosants despite the low incidence of clinical sequelae currently reported in the literature.
The second paper, presented by Dr. Gasparis from SUNY Stony Brook, was entitled “Prospective evaluation of the clinical deterioration in post-thrombotic limbs.” Fortyone patients with 46 femoral and/or popliteal vein DVTs were prospectively evaluated over a five-year period. The authors reported that over the period of observation, 30% of patients demonstrated progression of their chronic venous insufficiency. Three progressed from class 0 to class 3, 9 from class 3 to class 4 and 6, and 2 from class 4 to class 5 and 6. Clinical class progression was associated with recurrent DVT or progression of reflux. This study indicates that 30% of patients with femoral/popliteal DVT will demonstrate evidence of chronic venous insufficiency over a very short period of time and emphasizes the deleterious effects of recurrent DVT on the disease process.
The third paper, presented by Dr. Unno from the Hamamatsu University school of Medicine in Japan was entitled “Impaired lymphatic function recovered after great saphenous vein stripping in patients with varicose veins: Venodynamic and lymphodynamic results.” The investigators in this study utilized indocyanine green (ICG) fluorescence lymphography to measure lymph transit time before and after greater saphenous vein stripping. Dr. Unno indicated that six months after vein stripping, lymph transit time increased from 490 seconds to 340 seconds and correlated to improvements in venous hemodynamics. This paper provided objective data on the mechanism of edema relief after venous ablation surgery and justification for the effectiveness of current therapies.
The fourth paper, presented by Dr. Thors from Good Samaritan Hospital in Cincinnati, OH was entitled “Absorbable inferior vena cava filters (VCF): An in-vivo porcine model.” Dr. Thors reported the results of an absorbable filter device implanted in 10 pigs. The pigs were sacrificed at six weeks and the vena cavas excised en bloc. All filters were absorbed by six weeks. The Z stent portions of the filters were incorporated into the wall of the vena cava with complete neo-intimalization of the caval lumen. This industrious presentation attempts to address the need for temporary filter devices and the avoidance of secondary retrieval procedures. This device is in the early stages of its development and not commercially available yet.
The fifth paper, by Dr. Vinita Bahl from the University of Michigan, is titled “A validation study of a retrospective venous thromboembolism risk scoring method”. Dr. Bahl and colleagues retrospectively queried the National Surgical Quality Improvement Program database utilizing the Caprini risk assessment scoring system for the incidence of venous thromboembolism development. The Caprini risk assessment system categorizes patients into four categories (highest, high, moderate and low) for developing VTE according to a defined set of risk factors. The overall incidence of VTE in this patient population was 1.4% and correlated with the patient’s degree of risk and lack of VTE prophylaxis. This study was the first investigation to validate the Caprini risk assessment tool. Many hospitals are using risk assessment tools as part of the JCAHO initiative to reduce the incidence of VTE. Validation of this risk assessment tool provides hospitals with a way to develop guidelines for VTE prophylaxis and the ability to comply with government and JCAHO mandates concerning VTE.