A comparison between two different linear endovenous energy density (LEED) for great saphenous vein ablation using 1470-nm diode laser

A comparison between two different linear endovenous energy density (LEED) for great saphenous vein ablation using

1470-nm diode laser

Sherif Essam,a MD; Ahmed Farouk,a MD; Ahmed Abolnaga,a MD;

Ahmed Hossny,b MD; Atef Abdelhameed,a MD

a) Ain Shams Univeristy Hospitals, Cairo, Egypt.

b) Menoufia University Hospitals, Menoufia, Egypt.

Abstract

Introduction: The immediate  success rate of endovenous  occlusion of the great saphenous vein (GSV) and its durability after endovenous laser ablation (EVLA) was postulated to be the matter of a dose-response relationship to the amount of laser energy used.

Patients  and  methods:  Patients  presenting  with  varicose  veins  with  incompetent  GSV scheduled for EVLA were randomized into Group A who received low linear endovenous energy density (low LEED), and group B who received high linear endovenous energy density (High LEED) using the new 1470-nm diode laser. Patients were followed up for 6 months for the durability ofGSV occlusion and the occurrence of unwanted side effects after the procedure.

Results: Between April 2011 and May  2012, we treated 63 legs in 58 patients. We had no statistically  significant difference between the two groups regarding the occurrence of early post-operative side effects as pain, paraesthesia, and ecchymosis.

Regarding ultrasound proven durability ofGSV occlusion after 6 months, data showed total occlusion of the treated GSV segment in 24 out of 32(75%)  legs in group A versus 30 out of

31(96.7%)  legs in group B. This data indicates a statistically  significant difference (P= 0.04) regarding the failure of treatment in the treated GSV segment in group A patients who had the Low LEED 35J/cm in comparison to group B patients who had the High LEED 50J/cm.

Conclusion: The use of the 1470-nm diode laser radial fiber (ELVeS-radial kit) with a high

laser energy dose (LEED 50J/cm) was optimum in achieving a durable GSVocclusion without a significant increase in unwanted side effects when compared to lower laser energy dose (LEED

35J/cm).

Key words: Diode laser, great saphenous vein, laser ablation, LEED.

Introduction:

Approximately one-third  of  men  and women  aged  18  to  64  years  have  varicose veins.l

During  recent  years,  endoluminal treatment modalities have evolved  for the thermal  ablation  of the incompetent great saphenous  vein  (GSV).   In  the  last  decade, the spectrum  of treatment for  varicose  veins has been broadened. New, less invasive treatment options  than surgery  have been introduced, such  as ultrasound-guided foam

sclerotherapy, radiofrequency  ablation,  and endovenous laser ablation  (EVLA).

Soon  after  the  introduction  of  the endovenous  radiofrequency  closure technique,2 endovenous laser  ablation (EVLA) ofthe  GSV  was presented, initially using the haemoglobin specific  wavelength diode  lasers  with  810-nm,  940-nm, 980-nm, and 1064-nm wavelengths. This was followed by the introduction of the water specific wavelength 1320-nm laser and finally the new generation laser with a longer  wavelength of

1470-nm.  Some have  hypothesized  that the

1470-nm  laser efficacy would be higher due to higher specificity for the interstitial  water in the vessel wall and lower absorption by hemoglobin.3-5

From the very beginning, the immediate success rate of endovenous occlusion of the GSV  and  its  durability  were  in the  focus. Soon  it  became  apparent  that,  particularly after  EVLA,  recanalization  of  initially occluded GSVs is a relevant process that starts immediately thereafter.6,7 Multiple regression analysis of a prospectively obtained set of clinical data finally suggested that as soon as

3 months after laser treatment, there might be

a dose-response relationship between laser energy and a persistent occlusion of the GSV.8

Numerous randomized controlled trials (RCTs) and observational studies have compared the efficacy of endovenous laser ablation to surgery, sclerotherapy and radiofrequency   ablation  procedures,  but  to our knowledge, few studies have triggered the issue of dose-response relationship between linear endovenous energy density (LEED) applied to the vein wall using different laser wavelengths and a persistent occlusion of the GSV.

LEED  is best defined  as the  number  of joules delivered per centimeter  of the target vein during an EVLA procedure. Efficacy has been the primary endpoint of LEED studies, evaluating low LEED versus high LEED. In initial studies, Timperman etal9,10 determined that energy doses > 80 J/cm produced more efficacious  results  than  LEED  <  80  J/cm, with no difference  in side effects.  Similarly, another study concluded that LEED was the main  determinant  in the  success  of  EVLA, with  the  greatest  efficacy  occurring  at  an LEED > 60 J/cm.ll  Pannier et all2 evaluated a 1470-nm  laser, reporting  a 100% success rate with an average LEED of 107 J/cm for great saphenous vein treatment. It was noted that in the  limbs which received  a LEED >

100 J/cm, there was a considerably higher incidence of paraesthesia (15.5%) than limbs receiving < 100 J/cm (2.3%). The data from these studies suggest that the optimal LEED is in the range of60 J/cm to 100 J/cm. 9-12

In  this  study,  and  with  our  intention  to reach  the  lowest  amount  of energy  needed to obtain a durable GSV occlusion  with the least postoperative unwanted side effects, we prospectively followed up 2 different cohorts of patients for 6 months treated by 2 different linear endovenous energy density (LEED) using the 1470-nm diode laser radial fiber (ELVeS-radial kit) to compare the effect of these  2 different  LEEDs  on  recanalization rates as well as the occurrence of unwanted complications.

Patients and methods:

Our prospective,  randomized  study included consecutive patients who underwent EVLA of incompetent varicose veins. All patients  who  presented  to  our vascular surgery   unit,   with   symptoms   suggestive of symptomatic varicose veins, had their baseline examination including history, physical examination, and venous duplex ultrasound imaging of the lower extremity veins, then randomized into 2 groups. Group A patients received low LEED, and group B patients received high LEED.

Inclusion  criteria  for the  study were patients with varicose veins of clinical stage C2 or higher according to CEAP classification, and functional testing by duplex scanning showing an incompetent  GSV with reflux of more than 500 milliseconds after the Valsalva maneuver or manual augmentation with or without varicose tributaries necessitating phlebectomies.  We excluded  patients from EVLA treatment if the average size of the varicose vein was >12mm or if there was extreme tortuosity  of the  GSV. All patients gave informed consent for the procedure.

Venous ultrasound imaging during the procedure was performed using (SonoAce PICO, linear probe, HL5-9ED 7.5MHz/40mm Medison Co., Seoul, Korea).

The ELVeS-radial kit 1470-nm diode laser

(Cerelas D, Biolitec, Germany) consists of a

600 11m radial fiber with guidance markings, a 6 Fr sheath with 12 em introducer length, a

0.038 J-tip guide wire with 45 em length, and a 19G - 7 em entry needle. The radial fiber releases  its energy in a 360°  manner from a

nontraumatic  fiber tip. The entire procedure was guided by venous ultrasound imaging.

The GSV was punctured with duplex guidance  at  below  the  knee  level  with  the

19G   needle  followed   by   introduction   of the   0.038  1-tip  guide  wire  then  the   6Fr sheath.  Then  placement  of  the  laser  fibers was  performed  through  the  sheath   up  to a  level  2cm  distal  to  the  saphenofemoral junction  (SF1)  under  ultrasound  guidance. A  tumescent   local   anesthesia   was   given consisting of 25 mL of 2% Lidocaine, and 20 mL of sodium carbonate, diluted in 500 mL of saline along the perivenous space with the use of ultrasound guidance. Laser energy was delivered at 7W with LEED 351/cmfor group A patients, and at 1OW with LEED 501/cmfor group B patients using the radial fiber with a continuous pullback speed of 1cm/5 seconds. The  pullback  was  guided  by the  graduated laser fiber shaft with markers at 1cm intervals along the fiber shaft. The  GSV was treated from  2cm distal to the SF1to approximately

1 em above the skin entry site.

After the procedure, venous outflow was checked immediately in the proximal deep veins by ultrasound imaging, and additional treatment with mini phlebectomies in the leg using a Varady phlebectomy hook (Varady FB122, Aesculap) was applied if needed.

Immediately after the procedure, prophylaxis of venous thromboembolism with subcutaneous enoxaparin (40 mg) was given once. Compression therapy with a graduated class II stocking at 30 to 40 mm Hg was initiated immediately. Patients were to wear the stockings for 24 hours for 1 week, then during the day for another week. Diclofenac potassium (Cataflam), a nonsteroidal anti­ inflammatory drug was prescribed (50 mg, twice daily) for 7 days. The patient was told to resume routine daily activities immediately but to avoid strenuous exercise for about 1 week.

Follow-up  examinations  were performed at 1 week, 3 months, and 6 months after laser therapy  and  included  clinical  examination for  pain,  paraesthesia,  signs  of ecchymosis and  venous  ultrasound  imaging  to  examine the treated vein for recanalization  and also to

exclude deep vein thrombosis  (DVT)  in the leg.

Study   end   points.   The  primary   study end points were the occurrence of pain, paraesthesia, and ecchymosis  in the early postoperative period and ultrasound proven elimination  of  venous  flow  in  the  treated GSV segment after 6 months.

The distance from the saphenofemoral junction to the beginning of the occluded vein segment was measured, and if this distance exceeded  3 em or if any part of the treated GSV showed flow  signals  on augmentation or Valsalva maneuver, then the GSV was judged recanalized.  If recanalization  did not affect the  entire  length of the treated  GSV, then the recanalization was termed partial recanalization.

Statistical  analysis:  Differences  between the  study  groups  were  compared   by  Chi square  (X2)  test  for  categorical  variables, and students T test for continuous variables. Values ofP < 0.05 were considered significant.

Results:

Between   April   2011   and   May   2012, we  treated  63  legs  in  58 patients  with  the ELVeS-radial    kit     1470-nm    diode     laser (Cerelas  D, Biolitec,  Germany).  Procedures in patients  who  required  bilateral  treatment were  performed  at  different  sessions  with a  time  interval  of  4  weeks.  The  baseline characteristics  of  both  groups  are  reported in Table(l).  We had 58 patients (38 females,

65.5%  and  20  males,  34.5%)  with  a mean

age of 39.7±11.9 years.  Forty eight legs had symptomatic  varicose veins, with or without edema  (C2-C3),  and  fifteen  legs  had  skin changes with or without venous ulcers (C4- C6). Etiology was primary superficial valvular incompetence  in all patients.  Pre-procedure deep venous reflux  and/or  perforator  reflux was detected in 15 legs (23.8%); the detected deep  venous  reflux  was  negligible.   Great saphenous  vein  (GSV)  diameter  mean  was

7.7 +/-2.0 mm (range, 4 to 12 mm) for both groups. The cohorts showed no statistically significant differences in age, sex, clinical presentation,  and GS V diameter  before  the treatments, as described in Table(l).

Table (1): Demographic data and clinical presentation.

LEED, linear endovenous energy  density;  GSV, great saphenous vein; n, number;  SD,

standard  deviation.

We  didn't   have  any  of  our  patients   in both groups lost for follow up as they were contacted by phone  at time  of follow  up and we  did  not have  any  refusals  for follow  up. Thus, the  6-month follow-up data  could  be completed in 63 of 63 limbs (100%).  We did not have any cases of DVT in both groups as proved  by duplex scan throughout the follow up period.

Regarding our  study  end  points,  we  had no statistically significant difference  between the  two  groups  regarding the  occurrence of early  post-operative side effects.  Early  post­ operative   pain  occurred   in  3(9.4%) legs  in group A versus 4(12.9%) legs in group  B (p=0.65). None  of our patients  in both study groups  experienced paraesthesia in the post­ operative   period.   We  had   2(6.3%)   legs  in group A, who had post-operative ecchymosis versus   7(22.6%) legs  in  group   B  (p=0.06) which    was    nearly,   yet    not    statistically

significant as shown  in Table(2).

Our  results regarding ultrasound proven elimination of venous flow in the treated GSV after 6 months  showed, total occlusion ofthe treated  GSV  segment  in 24 out  of 32(75%) legs  in group  A versus  30 out  of 31(96.7%) legs in group  B, while there was partial recanalization in  the  treated   GS V  segment in 5(15.6%) legs in group  A versus  1(3.2%) leg in group  B, and  complete  recanalization in the  treated  GSV segment in 3(9.4%) legs in  group  A versus  0(0%)  legs  in  group   B. This data showed  a statistically significant difference  regarding the failure  of treatment in  the  treated   GSV  segment between   both groups with a P value of (P= 0.04) which indicates   a  higher  failure   rate  in  group   A patients who had the Low LEED 35J/cm in comparison to group  B patients  who had the High LEED  501/cm as shown  in Table(2).

Table (2): Outcomes after ELVeS-radial kit 1470-nm diode laser treatment.

GSV, great saphenous vein; n, number

Discussion:

Apart from the study  by Proebstle et all3 using the 910-nm diode laser in which energy is known to be absorbed by deoxygenated hemoglobin, no contemporary definition was postulated to the amount oflinear endovenous energy  density  (LEED)  needed  by the  new

1470-nm  diode  laser which  acts directly  on

the vessel wall through the absorption by the interstitial  water  with  its  lately  developed radial fiber that emits light at 360°, causing a homogenous alteration ofthe vein wall.

Previous studies conducted using different types of diode laser showed that the LEED below the target range led to failure of GSV occlusion, whereas, high LEED demonstrated increased side effects ofthe procedure.9-12

Proebstle et all3 postulated that the energy dose LEED is the crucial parameter in determining the balance between achieving durable GSV occlusion and the occurrence of post-operative side effects.

In  our  study,  we  confined  our  patient

selection to those with GSV diameter ranging between 4-12mm, which is the range in which the majority of our patients fall, in order to exclude those with too large GSV diameters who  will possibly  require  high energy  dose than the usual dose needed for the majority of patients.

For the purpose of comparing our two patients ' groups regarding the post-operative

ecchymosis  related  to  the  GSV  laser treatment,  we excluded patients who needed phlebectomies in the thigh region to avoid the conflict of whether the ecchymosis  was due to the laser dose applied to the GSV or to the phlebectomies  procedure.

This study demonstrates that for GSV diameters between  4 and  12mm, the applicationofLEEDof501/cm was associated with a significant higher GSV occlusion rate without a significant increase in unwanted side effects as pain, paraesthesia, and ecchymosis. Also the  use of  the  LEED  of  501/cm  was associated   with  a  durable  GSV  occlusion rate of96.7% which was comparable to other studies using higher energy doses in the range of 60 1/cm to 100 1/cm.9-12 Whereas the use of LEED  of 351/cm  was  associated  with  a nonsignificant lower rate of unwanted side effects yet with a significantly  higher rate of GSV recanalization.

Conclusion:

In this study we concluded that the use of the 1470-nm diode laser radial fiber (ELVeS­ radial  kit)  with  a  LEED  of  501/cm  at  10

Watts for GSV diameters between 4-12mm, was optimum in achieving a durable GSV occlusion comparable to higher laser energy doses without a significant increase in unwanted   side  effects  when  compared  to lower laser energy doses.