EHIT: Incidence in a large collective after standardized endovenous laser Johann Chris Ragg, MD angioclinic vein centers Berlin (D) Munich (D) Zurich (CH) Background The term EHIT (endothermal heat induced thrombosis) has been established in recent years, representing a major complication of thermal saphenous treatment in the location of the saphenofemoral or saphenopopliteal junction, with incidence up to 6% 3. Four classes have been defined, for the, depending on the propagation of thrombus and the degree of lumen closure 1,2. We reviewed a large collective undergoing endoluminal laser ablation according to standardized protocols, to determine the influence of technical details on EHIT.. a Fig. 2: Tip position (a) for radial geometry make shure there is no irradiation of blood, but just tumescence-covered vein wall. (b) for foreward-beaming fibers: Distance to femoral level should equal residual lumen width, < 3 mm. b a Fig. 4: Junction morphology, a) preserving epigastric vein outflow, b) total closure at femoral level. Both images show intended closure on the basis of endothelium denaturation, different to EHIT class 1, in spite of similar appearance. b Careful no-touch injection unto femoral level 5 mm cross-sectional view Conclusions According to the presented data, EHIT is a well preventable event, even without standard anticoagulation, depending on 1) adequate thermal insulation including complete circumferential fluid layers, adhering the vein wall to the laser probe and 2) precisely located heat activation, related to the geometry of the device used. Fig. 1: EHIT classes according to Werth et al./kabnick et al. Patients/Methods Retrospective study of 8.550 cases of thermo-occlusion according to the angioclinic protocol (Laser 810-2000 nm), performed 2009-2016 with completed standard follow up after 2 and 8 weeks. Distance to femoral level was chosen according to fiber geometry (Fig. 2). Furthermore, coaxial perivenous local anesthesia (CPLA) was used for circumferential thermal insulation 4 instead of common tumescence, with a minimum layer thickness of 5 mm (Fig. 3). Anticoagulants were given only in case of known thrombophilia (n = 26), and in case of protocol failure. a Fig. 3: Technique of CPLA, schmene (a). Minimum insulation layer: 5 mm. No distance between tool and endothelium. Results No case of EHIT in the sense of incidental thermal effect around the junction was detected during FU. 12 patients (0.14%) received NMH due to protocol failure, like incidental laser activation within femoral or popliteal vein. 7 cases of DVT (0.08%) were registered during (n = 4) or after (n = 3) eight weeks of follow-up, two of them included a treated junction (SSV), occurring week 3 and 6 after perfect intermediate status, thus not counted as EHIT but spontaneous events. b Literature 1 Kabnick LS. Endovenous heat induced thrombus (EHIT) following endovenous vein obliteration: to treat or not to treat? 18th Ann Meet AVF Feb 23, 2006, Miami Florida. 2 Harlander-Locke M, et al. Management of endovenous heat-induced thrombus using a classification system and treatment algorithm following segmental thermal ablation of the small saphenous vein. J Vasc Surg 2013 Aug; 58(2): 427 432. 3 Werth S, Halbritter K, Mahlmann A, Weiss N. Treatment of endovenous heatinduced thrombosis (EHIT) with rivaroxaban (Xarelto ) Phlebologie 2015; 44: 184 187 http://dx.doi.org/10.12687/phleb2264-4-2015 4 Ragg J. C. Endovenöse Lasertherapie: Ist das Ergebnis abhängig von der Tumeszenzanästhesie? Phlebologie 4-2007 A9-15 Work Group Dr. Ragg See videos on www.venartis.org
C C < 50% EHIT class 1 C > 50% C EHIT class 3 EHIT class 4
C C < 50% EHIT class 1 C > 50% C EHIT class 3 EHIT class 4
C C < 50% Laser crossectomy C > 50% C EHIT class 3 EHIT class 4