CAE indicates cyanocrylate adhesive injection; MOCA, mechanochemical ablation.
aThe number and percentage of patients who returned for each follow-up.
VAS indicates visual analog scale.
Data analysis plan
eFigure 1. 10 Day Postoperative Pain Scores
eFigure 2. Disease specific quality of life – AVVQ and CIVIQ-14
eFigure 3. General quality of life - EQ-5D and EQ- VAS
eFigure 4. Clinical Disease Severity – VCSS
eFigure 5. Time to return to normal activities, work and stop wearing compression
eTable 1. Summary of Inclusion and exclusion criteria used in MOCCA study
eTable 2. Summary of Truncal ablation technique used in MOCCA study
eTable 3. Shows the maximum and the average pain score for those had ambulatory phlebectomy or foam sclerotherapy
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Belramman A, Bootun R, Tang TY, Lane TRA, Davies AH. Pain Outcomes Following Mechanochemical Ablation vs Cyanoacrylate Adhesive for the Treatment of Primary Truncal Saphenous Vein Incompetence: The MOCCA Randomized Clinical Trial. JAMA Surg. 2022;157(5):395–404. doi:10.1001/jamasurg.2022.0298
Is there a difference in the amount of pain experienced when patients with primary saphenous vein incompetence are treated with mechanochemical ablation or cyanoacrylate adhesive?
In this randomized clinical trial, the median scores for maximum and average pain experienced were low and similar between the mechanochemical ablation and cyanoacrylate adhesive groups.
Findings of this study indicate that both nontumescent ablation techniques had comparable outcomes, suggesting that determining which interventions to use can be based on cost-effectiveness and clinician and patient preference.
Endovenous thermal ablations (ETAs) are recommended as first-line treatment for truncal vein reflux, have a short recovery time, and are cost-effective. However, ETAs are associated with discomfort during tumescent anesthesia infiltration. To minimize discomfort, nonthermal, nontumescent ablation techniques had emerged in the form of mechanochemical ablation (MOCA) and cyanoacrylate adhesive injection (CAE).
To assess pain scores immediately after truncal ablation using a 100-mm visual analog scale and 10-point number scale to compare pain-related outcomes following mechanochemical ablation vs cyanoacrylate adhesive treatment.
Design, Setting, and Participants
The Multicenter Randomized II Clinical Trial Comparing Mechanochemical Ablation vs Cyanoacrylate Adhesive for the Treatment of Primary Truncal Saphenous Veins Incompetence study was a prospective multicenter randomized clinical trial conducted at 3 sites between November 2017 and January 2020. Inclusion criteria were primary great or small saphenous varicose veins; exclusion criteria included recurrent varicose veins, current deep venous thrombosis, or serious arterial disease. There were 392 participants screened, 225 were excluded, and 167 participants underwent randomization. Four participants did not receive allocated intervention and were included in the intention-to-treat analysis. Follow-up took place at 2 weeks, and 3, 6, and 12 months.
Patients with primary truncal vein incompetence were randomized to receive either MOCA or CAE.
Main Outcomes and Measures
The primary outcome measure was pain score immediately after completing truncal ablation using a 100-mm visual analog scale (VAS) and a 10-point number scale. Secondary outcome measures included degree of ecchymosis, occlusion rates, clinical severity, and generic and disease-specific quality of life (QoL) scores.
Of 167 study participants, 99 (59.3%) were women, and the mean (SD) age was 56 (15.8) years. Overall, 155 truncal veins treated (92.8%) were great saphenous veins. Demographic data and baseline status were comparable between treatment groups. A total of 73 patients (47%) underwent adjunctive treatment of varicosities. Overall median (IQR) maximum pain score after truncal treatment was 23 mm (10-44) on the VAS and 3 (2-5) on the number scale, showing no significant difference in median (IQR) pain measured by VAS (MOCA, 24 [11.5-44.7] mm vs CAE, 20 [9.0-42.0] mm; P = .23) or by number scale (MOCA, 4 [2-5] vs CAE, 3 [2-4]; P = .18). Both groups demonstrated significant and comparable improvement in clinical severity, generic and disease-specific QoL scores, and complete occlusion rates. Four patients treated with CAE developed minor complications (superficial thrombophlebitis and thrombus extensions).
Conclusions and Relevance
To our knowledge, this was the first randomized clinical trial directly comparing nontumescent ablation techniques. The study demonstrated that the MOCA and CAE techniques have a similar periprocedural pain score.
ClinicalTrials.gov Identifier: NCT03392753.
Varicose veins affect up to one-third of the adult population worldwide.1 They are known to have a considerable detrimental impact on patients’ health-related quality of life (QoL).1 Varicose veins also carry a growing economic cost owing to an aging population and increasing rates of advanced disease.2 Treatment of symptomatic varicose veins has been shown to improve QoL.3-5 Endovenous ablation with catheter-based technologies has led to a paradigm shift from open surgery, allowing specialists to perform them in an outpatient or office-based setting.6 Currently, both the National Institute of Clinical Excellence and the American Venous Forum recommend endovenous thermal ablations (ETAs), namely, radiofrequency ablation and endovenous laser ablation, as the first-line treatment of saphenous veins reflux.7 ETAs demonstrate a short recovery time and are cost-effective compared with open surgery. Occlusion rates greater than 90% have been reported for ETA at up to 5 years of follow-up.8-11 ETAs denature the venous wall using thermal energy; thus they can be associated with complications, such as pain, skin burns, skin pigmentation, nerve damage, and arteriovenous fistula formation.12,13 To minimize these possible complications, tumescent anesthesia is infiltrated around the vein; however, these injections can increase procedural discomfort. Foam sclerotherapy is an alternative to ETAs. However, long-term results have shown inferior efficacy compared with other treatment technologies.14
To minimize negative aspects of these ETAs, nonthermal, nontumescent ablation techniques (NTNTs) were developed. Because no heat is used, no tumescent anesthesia is needed. Mechanochemical ablation (MOCA)15 and cyanoacrylate adhesive injection (CAE)16 are examples of these NTNTs. The National Institute of Clinical Excellence has published interventional procedure guidance for both MOCA17 and CAE.18 Pain has been found to be less than19-24 or comparable with ETAs,25,26 as well as equivalent to ETAs in terms of QoL improvement, time to return to normal activities or work, and occlusion rates.27,28 Thus, NTNTs could potentially be considered favorable to ETAs.
To our knowledge, there has been no head-to-head comparison of the 2 NTNTs techniques. Therefore, we performed the Multicenter Randomized II Clinical Trial Comparing Mechanochemical Ablation vs Cyanoacrylate Adhesive for the Treatment of Primary Truncal Saphenous Veins Incompetence (MOCCA) study comparing MOCA with CAE in the treatment of varicose veins, aiming to assess pain scores after truncal ablation.
Full details relating to the study design, eligibility criteria, and outcomes are provided in the previously published protocol29 (Supplements 1 and 2). In brief, the MOCCA study was a prospective multicenter randomized clinical trial comparing MOCA and CAE. It was conducted at 3 sites: Charing Cross Hospital (Imperial College Healthcare National Health Service Trust); Singapore General Hospital; and Sengkang General Hospital. From November 6, 2018, to January 13, 2020, potential participants were screened for eligibility (eTable 1 in Supplement 3). Ethical approval was obtained from the Regional Research Ethics Committee London, and the study conformed to the Declaration of Helsinki.
Enrollment of participants was performed by a study member outside of the treating team. On the day of treatment and after informed consent were obtained; randomization was carried out using a web-based computerized randomization system.30 Blinding after randomization was not possible for either surgeons or participants owing to the nature of the interventions. However, treatment allocation was masked from assessors who carried out follow-up assessments and duplex ultrasonography scan (DUS).
All interventions were performed under ultrasonography guidance using local anesthesia and carried out according to instructions for use by vascular surgeons who have experience in both MOCA and CAE techniques (eTable 2 in Supplement 3). Immediately after completion of the truncal ablation, patients were asked to indicate the amount of pain they had experienced on a 100-mm visual analog scale (VAS) and a 10-point number scale. Patients were provided with a sheet of paper with the scales on which to mark their individual scores. Once the pain score was recorded, according to the discretion of the treating clinical team, adjunctive procedures were performed if deemed necessary (ie, concomitant phlebectomy or foam sclerotherapy). Pain scores post–adjunctive procedures were also recorded. No routine preoperative or intraoperative pain medication was prescribed. Following interventions, a DUS was carried out to assess the treated truncal vein and the deep venous system. To treat patients similarly, all patients were discharged with instructions to wear class II compression stockings for 4 days. Patients were also provided with a diary and instructed to record their postoperative pain for 10 days and record when they could return to normal activities, including work and when they stopped wearing compression stockings.
Patients attended follow-up visits, had a clinical assessment, and were requested to complete QoL questionnaires at 2 weeks and then at 3, 6, and 12 months. The diary was collected at 2 weeks. A DUS was performed at 3, 6, and 12 months. There were 4 possible findings on postintervention duplex ultrasonography scanning21: complete occlusion, proximal occlusion, distal occlusion, and opening of the saphenous vein.
The primary outcome measure was the pain score immediately after completing the truncal ablation using a 100-mm VAS and a 10-point number scale. The secondary outcome measures were pain scores post–adjunctive procedures, 10-day postoperative pain score, degree of ecchymosis,31 time to return to normal activities or work, time to stop wearing compression stockings, occlusion rates, clinical severity scores (Venous Clinical Severity Score [VCSS], Venous Disability Score [VDS], and Clinical Etiology Anatomy Pathology score)32,33; and generic (EuroQol 5 Domain 3-Level and EuroQol VAS)34,35 and disease-specific (Aberdeen Varicose Vein Questionnaire) and chronic venous insufficiency quality of life questionnaires36-38 QoL scores.
In previous studies, a difference of 10 mm was considered a minimum clinically significant difference.21,39,40 Therefore, a mean difference of at least 10 mm with a standard deviation of 20 mm between treatment groups in the primary outcome of pain score during truncal ablation as measured by VAS was used to calculate the sample size. The target sample size was calculated for 80% power of testing and a 5% level of significance, and 64 patients per group were required (128 in total). Allowing for 30% loss to follow-up, the target recruitment was estimated to be 183 patients.
Data were analyzed using IBM SPSS Statistics version 27.0.1 (IBM), Stata version 17.0 (StataCorp), and Wizard version 2 (Evan Miller) on an intention-to-treat basis. Normality of the distribution of the data was assessed using visual inspection, Kolmogorov-Smirnov and Shapiro-Wilk tests, and then parametric and nonparametric tests. Accordingly, either 1-way repeated measures analysis of variance or related samples of Friedman 2-way analysis of variance were used for paired data. Bonferroni correction was used where appropriate, and χ2 tests were applied for categorical data and reported as frequencies and proportions (as percentages). Statistical significance was set at P < .05. However, as interim analyses were carried out 1 year from the beginning of recruitment,41,42 the α spending function of Lan and DeMets approaches43,44 was used to control the number of type I errors.
Baseline patient characteristics are summarized in Table 1 and were comparable in both groups. A total of 167 participants consented and underwent randomization, of whom 99 (59.3%) were women. The mean (SD) age in the study population was 56 (15.8) years. Table 2 summarizes characteristics of the veins treated. Overall, 155 of the truncal veins treated (92.8%) were GSVs. The median treated truncal vein diameter was comparable in both groups. However, the median procedure duration for GSVs was significantly shorter for MOCA than for the CAE group (MOCA, 17 minutes [IQR,14.3-20.3] vs CAE, 22.7 minutes [IQR, 17.5-27.2]; Mann-Whitney U test, P = .001). There was no difference in proportion of adjunctive treatment.
There were 392 participants screened, 225 of whom were ineligible or declined to participate. The common reason for declining participation was unwillingness or inability to attend follow-up appointments, declining randomization, preference for a different intervention, or because of the lack of clinical equipoise. Four participants did not receive the allocated intervention and were included in the intention-to-treat analysis. The COVID-19 pandemic impacted the number and proportion of participants who attended follow-up appointments, as shown in the CONSORT diagram (Figure 1). By 12 months, 70 patients (41%) were lost to follow-up or dropped out.
Overall, the median (IQR) maximum pain score experienced during truncal treatment was 23 (10-44) mm on a VAS and 3 (2-5) mm on the 10-point number scale. Distributions of the maximum pain scores for MOCA and CAE were similar. The median (IQR) maximum pain scores measured by VAS for MOCA and CAE were 24 (11.5-44.7) mm and 20 (9-42) mm (P = .23), respectively. As measured on a 10-point number scale, median (IQR) for MOCA was 4 (2-5) compared with 3 (2-4) for CAE (P = .18) (Figure 2). There was a statistically significant positive correlation between VAS and number scale (r = 0.78, P < .001). Most patients (118 [83.7%]) in both NTNT groups experienced maximum pain for a few seconds vs a few minutes or more than a few minutes.
The overall median average (IQR) pain score experienced at the end of truncal treatment was 10.5 (3-25) mm on the VAS and 3 (3-4) on the 10-point number scale. Distributions of the average pain scores for MOCA and CAE were similar. The median average (IQR) pain score measured on VAS for MOCA was 8 (3-22) mm and 11 (4-27) mm for CAE (P = .26). On the number scale, median (IQR) average MOCA scores were 4 (2-5) compared with 3 (2-4) for CAE (P = .66) (Figure 2). There was a statistically significant positive correlation between VAS and number scale for average pain (r = 0.68; P < .001).
Table 3 summarizes all secondary outcomes. The overall median (IQR) pain score reported in the 10 days postoperatively was 9.75 (2.9-16.75) mm on the VAS. The median (IQR) pain score for MOCA was 10.5 (3-16) mm and CAE 7 (2.5-19) mm. This difference was not statistically significantly (eFigure 1 in Supplement 3).
There were no significant differences in disease-specific QoL scores between the 2 treatment groups over the follow-up period. The Aberdeen Varicose Vein Questionnaire score in both groups improved significantly by the third and sixth months, and these improvements were preserved to 12-month follow-up (χ24 = 99.48; P < .001). Post hoc analysis revealed a statistically significant reduction in Aberdeen Varicose Vein Questionnaire scores from baseline (median [IQR], 14.14 [8.78-23.00]) to 3 months (median [IQR], 4.76 [2.00-13.20]; P < .001), 6 months (median [IQR], 5.01 [1.66-12.50]; P < .001), and 12 months (median [IQR], 4.76 [1.00-12.49]; P < .001), but not at 2 weeks. Similarly, chronic venous insufficiency quality of life questionnaire scores were also statistically significant improved at follow-up (χ24 = 55.44; P < .001, Friedman). Post hoc analysis showed statistically significant differences in chronic venous insufficiency quality of life questionnaire scores from baseline (median [IQR], 19.64 [7.10-39.20]) to 2 weeks (median [IQR], 12.50 [3.57-30.35]; P = .03), 3 months (median [IQR], 5.35 [0-16.00]; P < .001), 6 months (median [IQR], 5.35 [0-19.10]; P < .001), and 12 months (median [IQR], 5.35 [0-30.90]; P < .001) (eFigure 2 in Supplement 3).
Both groups showed significant improvement at 6-month follow-up, which was maintained to 12 months’ follow-up in the EQ-3D VAS (χ24 = 19.58; P < .001, Friedman). Significant improvements were seen in EQ-5D at 3-month follow-up and sustained to 12 months (χ24 = 39.74; P < .001, Friedman). No significant difference was seen between treatment groups (eFigure 3 in Supplement 3).
Patients in both groups demonstrated significant improvement in VCSS (eFigure 4 in Supplement 3) and VDS, which was maintained to 12-month follow-up (VCSS χ24 = 121.42; P < .001; VDS χ24 = 79.28; P < .001, Friedman) with no significant difference between groups.
Return to normal activities and work was similar for both groups (eFigure 5 in Supplement 3). The degree of ecchymosis was also similar for both groups. Both groups were equally compliant with postoperative compression (eFigure 5 in Supplement 3) and the occlusion rate at 12 months was also equivalent.
Adjunctive treatment of the varicosities, in addition to truncal ablation, was performed in 73 patients (47.1%; 19 [25.3%] foam sclerotherapy and 56 [74.7%] ambulatory phlebectomy; not mutually exclusive). Overall, the median (IQR) maximum pain score experienced at the end of adjunctive treatment was 23.00 (7.25-42.7) mm on the VAS and 5 (2-6) on the number scale and the median (IQR) average pain score was 18.5 (6.25-36.7) mm on the VAS and 3 (2-5) on the number scale. Patients who had CAE and ambulatory phlebectomy reported slightly higher pain scores, but this was not significantly different. eTable 3 in Supplement 3 shows maximum and average pain scores for those with ambulatory phlebectomy or foam sclerotherapy.
No major complications were reported with DVT or pulmonary embolus. Four patients treated with CAE and adjunctive procedures developed minor complications: 3 superficial thrombophlebitis and 1 thrombus extension (endovenous glue-induced thrombosis).45
The first superficial thrombophlebitis case was in a patient receiving extended VTE prophylaxis postprocedure. Treatment was GSV CAE ablation and foam sclerotherapy (below knee, 10 mL). Three months after the intervention, the patient presented with calf pain. DUS identified chronic occlusion of the treated veins without DVT, and no treatment was required. The other 2 cases of superficial thrombophlebitis developed in patients treated for GSV incompetence and ambulatory phlebectomy. The superficial thrombophlebitis developed in the truncal vein and resolved without treatment.
One thrombus extension to the level of the common femoral vein occurred (endovenous glue-induced thrombosis) in an elderly patient treated for GSV incompetence at 6 weeks. Although the patient was asymptomatic, he was treated with anticoagulation. Repeated DUS confirmed no thrombus in the common femoral vein and the anticoagulation was stopped.
The treatment of superficial venous insufficiency in patients with symptomatic varicose veins has been shown to improve QoL. The primary outcome of this study was pain score after truncal ablations as measured by VAS. Our findings showed that maximum and average pain score were low and similar between the MOCA and CAE groups. There was no statistically significant difference between treatment groups in pain experienced in the 10 days postoperatively, return to normal activities or work, ecchymosis score, and occlusion rates. The median clinical and QoL scores significantly improved in both groups after treatment with no difference between the groups.
Previous studies support the results of our study, demonstrating lower pain scores following NTNTs compared with ETAs, including both RFA19-23,26 and EVLA.23-25 In agreement with established ETA techniques, a statistically significant and clinically relevant improvement in the clinical and QoL scores posttreatment have been reported in systematic reviews and meta-analyses.27,46
The complete occlusion rates at 3, 6, and 12 months’ follow-up were equivalent for both techniques; however, the number of patients who had postintervention duplex ultrasonography scanning were low as the ongoing COVID-19 pandemic affected follow-up visits. The overall complete occlusion rates observed are consistent with the literature.
The duration of procedure was significantly longer in patients treated with CAE (17 vs 21 minutes; P < .001). The reason for this is that the instructions for use of this technique require waiting for 3 minutes for the first 4 cm of vein. Postprocedural compression is not required following CAE; however, patients in both groups were provided with stockings so that postoperative treatment was similar between groups.
There were no major complications, such as DVT or pulmonary embolus, in either group in our study. However, superficial thrombophlebitis and thrombus extensions were observed in patients treated with CAE, but only the patient with endovenous glue-induced thrombosis required treatment.
This study found no difference in outcomes following MOCA or CAE, and previous studies have demonstrated that NTNTs have similar outcomes to ETAs. This would suggest that the main determinant as to which interventions to use would be surgeon and patent preference and the cost-effectiveness of each technique. This is especially important, as the COVID-19 pandemic has placed a considerable burden on many health systems around the world, and only limited resources may be available to treat benign but QoL-affecting conditions like varicose veins. The current list price for MOCA devices is approximately £375 ($496.30) and for CAE devices used in this study is £640 ($847.00). This suggests that with similar QoL outcomes and occlusion rates but a shorter procedural time and lower device cost, MOCA is likely to be more cost-effective than CAE if assessed formally.47
Strengths of this study include that it was based on a prospective randomized clinical trial with prespecified outcome measures in the published study protocol. However, there are limitations in our study. The first limitation was a lack of interventional blinding owing to the different device techniques, although this was mitigated by blinded follow-up assessments. Second, because of the COVID-19 pandemic, 70 patients (41%) were lost to follow-up or dropped out by 12 months. However, the proportion did not differ between those who dropped out and those who did not, and this limitation was controlled by conducting intention-to-treat analysis with the primary outcome recorded on day zero. This would suggest that the confidence in the primary outcome can be strong. Additionally, although both groups were assessed for a pain score 10 days postoperatively, the use of analgesia was not reported.
This randomized clinical trial compared 2 different NTNT techniques in treating truncal veins insufficiency. The results demonstrated that both techniques were similar in terms of periprocedural pain score. Additional well-designed randomized clinical trials with longer-term follow-up would be needed to assess the longer-term efficacy and cost-effectiveness of using NTNT techniques in treatment of saphenous veins reflux.
Accepted for Publication: January 9, 2022.
Published Online: April 6, 2022. doi:10.1001/jamasurg.2022.0298
Corresponding Author: Alun H. Davies, MA, DM, Department of Surgery and Cancer, Imperial College London, 4N12A, Charing Cross Hospital, Fulham Palace Road, London W6 8RF, United Kingdom (email@example.com).
Author Contributions: Dr Belramman and Mr Bootun had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.
Concept and design: Bootun, Lane, Davies.
Acquisition, analysis, or interpretation of data: All authors.
Drafting of the manuscript: Belramman, Tang, Lane, Davies.
Critical revision of the manuscript for important intellectual content: All authors.
Statistical analysis: All authors.
Obtained funding: Davies.
Administrative, technical, or material support: Tang, Lane, Davies.
Supervision: Bootun, Tang, Lane, Davies.
Conflict of Interest Disclosures: Dr Tang reports grants from Medtronic and speaking honoraria from Merit Medical. No other disclosures were reported.
Data Sharing Statement: See Supplement 4.
Additional Contributions: We thank the patients who participated in this study. We also thank the teams at Charing Cross Hospital, London, United Kingdom, Singapore General Hospital, and Sengkang General Hospital, Singapore.