SITE 2013 Barcelona, May 8th to 11th, 2013 Laser Fluence Affects Recanalization after Endovenous Laser Therapy for Saphenous Varicose Veins 1. Tokyo Vein Clinic 2. Tokyo Metropolitan Geriatric Hospital, Department of Vascular Surgery Go Urabe1,2, Keisuke Kondoh1, Tatsu Nakazawa2 Today, I’ll talk about recanalization of endovenous laser therapy for saphenous varicose veins. TOKYO VEIN CLINIC

Background and study purpose Recently, the number of Endovenous Laser Therapy (EVLT) for Saphenous Varicos Veins is increasing instead of conventional stripping. Recanalization after EVLT is rare, but it often needs additional treatments. The risk factor of recanalization remains uncertain. This study aims to investigate its risk factors. Let me first talk about the background of this study. In Japan, endovenous laser therapy on saphenous varicose vein has been covered by health insurance, since January 2011. So, number of EVLT is increasing.

Study design We defined recanalization as patency of ablated saphenous vein more than five centimeter from the saphenous junction Risk factors for recanalization were compared with occluded veins and recanalized veins by univariate and multivariate analyses Retrospective study In this study, we defined recanalization as total longitudinal patency of ablated saphenous vein, because partial patency is not clinically important. Risk factors for recanalization were compared with occluded and recanalized veins by univariate and multivariate analyses. And this is a retrospective study with medical record.

Risk factors Age Sex Saphenous vein (GSV or SSV) Medication of anticoagulant drugs Maximum diameter of the proximal vein (mm) LEED: linear endovenous energy density (J/cm) Laser fluence (J/cm2) These are list of risk factors analysed in this study. Let me talk about the last two factors of laser energy.

Indices of laser energy LEED: Linear Endovenous Energy Density {Laser energy (J)} / {Length (cm)} Laser fluence: {LEED (J/cm)} / {Max. diameter of proximal vein (cm)} LEED (J/cm) LEED is a linear endovenous energy density: J/cm. On the other hand, laser fluence is an energy density of vascular surface area: J/cm2. In this study, we defined laser fluence as LEED divided by maximum diameter of proximal saphenous vein (cm) Fluence (J/cm2)

Patients From January 2011 to June 2012, 850 saphenous varicose veins in 648 patients were performed EVLT with ELVeSTM laser (wave length: 980nm) at Tokyo Vein Clinic

Procedure of EVLT Patients were put under sedation with intravenous injection of midazolam and propofol Saphenous vein was accessed by puncturing with duplex guidance Tumescent local anesthesia was infiltrated in the saphenous compartment with duplex guidance From the position of 1-2 cm distal to the SFJ, laser fiber was withdrawn with continuous laser energy of 8-10W We don’t perform stab phlebectomy

Post operative follow up Duplex scan was performed at one week, 1, 3, 6, and 12 months after the operation We recommend patients to wear elastic stockings for three months after the operation At the early period from January to February 2011, we didn’t care about laser ablation power. But, from March 2011, we controlled it as 70-80 J/cm. Post operative follow up with duplex scan was performed at 1 week and at 1,3,6, and 12 months after the operation. Patients wore elastic stockings for three months after the operation.

Background of patients Age 60.2±11.2 y.o.（13-88 y.o.） Sex　 female 　643 limbs in 483 patients male 207 limbs in 165 patients Vein great saphenous vein 688 limbs small saphenous vein 162 limbs Medication 33/648 patients (5.1%) Max. diameter of vein (mm) 12.0±3.7 (3.4-22.5) LEED (J/cm) 71.7±11.6 (28.9-117) Laser fluence (J/cm2) 66.3±26.1 (17.9-216) This table shows patient’s background.

List of recanalized veins 12/850 veins (1.4%) Age Sex Vein Medication Max diam. (mm) LEED (J/cm) Fluence (J/cm2) Duration Partial / Total Recanalization Reoperation 48 M GSV - 13.1 46.2 35.3 3M T 71 F 13.7 41.5 30.3 1W + 40 13.0 47.4 36.5 39 11.4 82.8 72.6 58 SSV 16.3 82.3 50.5 1M 13.4 65.3 48.7 P 65 15.8 76.5 48.4 9.7 79.7 82.2 44 19.1 78.7 41.2 60 14.5 85.3 58.8 19.9 74.6 37.5 75 81.9 63.0 Recanalization occurred in 12 limbs of 12 patients. This table shows most of our recanalization occurred within a month after the operation. We performed re-operation for veins of total recanalization.

Univariate analyses of risk factors occluded n=838 recanalized n=12 p value Age 60.2±11.1 58.0±12.5 0.49* Sex (female) 632/838 (75.4%) 11/12 (91.7%) 0.19# Vein (GSV) 676/838 (80.7%) 0.34# Medication 41/838 (4.9%) 2/12 (17%) 0.065# Max diameter (mm) 11.96±3.68 14.41±2.96 0.022* LEED (J/cm) 71.8±11.5 70.2±16.1 0.64* Laser fluence (J/cm2) 66.5±26.1 50.4±16.0 0.033* Among these, p value of 0.2 or less were taken into multivariate analysis. #　Pearson’s χ2 test , *　Student’s t test

Multivariate analysis of risk factors Logistic regression analysis (Stepwise method) Risk factor p value X2 Max. dimeter 0.817 0.054 Medication 0.062 3.50 Laser fluence 0.021 5.35 Multivariate analysis showed laser fluence was the only significant risk factor.

Box plot of laser fluence (J/cm2) Laser fluence Recanalized Occluded

Receiver operating characteristic (ROC) curve of laser fluence and recanalization 63.0 Sensitivity 50.5 Values at the dots are laser fluence (J/cm²) 41.2 1 - (Specificity)

Conclusion Our recanalization rate was 1.4% Most of our recanalization occurred within a month from the operation Laser fluence was the only significant risk factor of recanalization Laser energy should be controlled by the diameter of the vein

Study limitations Laser fluence was defined as LEED (J/cm) / {max. diameter of the proximal vein (cm)} precise location of venous max. diameter was not taken into consideration Velocity of laser fiber withdrawal was not constant LEED and laser fluence were not constant through the saphenous vein