A randomized trial of vonapanitase (PATENCY-1) to promote radiocephalic fistula patency and use for hemodialysis.

OBJECTIVE: Arteriovenous fistulas created in patients with chronic kidney disease often lose patency and fail to become usable. This prospective trial evaluated the efficacy of vonapanitase, a recombinant human elastase, in promoting radiocephalic fistula patency and use for hemodialysis. METHODS: PATENCY-1 was a double-blind, placebo-controlled trial that enrolled 349 patients on or approaching hemodialysis and being evaluated for radiocephalic arteriovenous fistula creation. Of these, 313 were randomized and 311 treated. Patients were assigned to vonapanitase (n = 210) or placebo (n = 103). The study drug solution was applied topically to the artery and vein for 10 minutes immediately after fistula creation. The primary and secondary end points were primary patency (time to first thrombosis or corrective procedure) and secondary patency (time to abandonment). Tertiary end points included use of the fistula for hemodialysis, fistula maturation by ultrasound, and procedure rates. RESULTS: The Kaplan-Meier estimates of 12-month primary patency were 42% (95% confidence interval [CI], 35-49) and 31% (95% CI, 21-42) for vonapanitase and placebo (P = .25). The Kaplan-Meier estimates of 12-month secondary patency were 74% (95% CI, 68-80) and 61% (95% CI, 51-71) for vonapanitase and placebo (P = .048). The proportions of vonapanitase and placebo patients were 39% and 25% (P = .035) with unassisted use for hemodialysis and 64% and 44% (P = .006) with unassisted plus assisted use. CONCLUSIONS: Vonapanitase treatment did not significantly improve primary patency but was associated with increased secondary patency and use for hemodialysis. Further research is needed to evaluate these end points.

PATENCY-2 trial of vonapanitase to promote radiocephalic fistula use for hemodialysis and secondary patency.

OBJECTIVE: Arteriovenous fistulas created for hemodialysis often fail to become usable and are frequently abandoned. This prospective trial evaluated the efficacy of vonapanitase, a recombinant human elastase, in increasing radiocephalic fistula use for hemodialysis and secondary patency. METHODS: PATENCY-2 was a randomized, double-blind, placebo-controlled trial in patients on or approaching the need for hemodialysis undergoing radiocephalic arteriovenous fistula creation. Of 696 screened, 613 were randomized, and 603 were treated (vonapanitase n = 405, placebo n = 208). The study drug solution was applied topically to the artery and vein for 10 min immediately after fistula creation. The primary endpoints were fistula use for hemodialysis and secondary patency (fistula survival without abandonment). Other efficacy endpoints included unassisted fistula use for hemodialysis, primary unassisted patency, fistula maturation and unassisted maturation by ultrasound criteria, and fistula procedure rates. RESULTS: The proportions of patients with fistula use for hemodialysis was similar between groups, 70% vonapanitase and 65% placebo, (p = 0.33). The Kaplan-Meier estimates of 12-month secondary patency were 78% (95% confidence interval [CI], 73-82) for vonapanitase and 76% (95% CI, 70-82) for placebo (p = 0.93). The proportions with unassisted fistula use for hemodialysis were 46% vonapanitase and 37% placebo (p = 0.054). The Kaplan-Meier estimates of 12-month primary unassisted patency were 50% (95% CI, 44-55) for vonapanitase and 43% (95% CI, 35-50) for placebo (p = 0.18). There were no differences in the proportion of patients with fistula maturation or in fistula procedure rates. Adverse events were similar between groups. Vonapanitase was not immunogenic. CONCLUSIONS: Vonapanitase treatment did not achieve clinical or statistical significance to meaningfully improve radiocephalic fistula surgical outcomes. Outcome in the placebo group were better than in historical controls. Vonapanitase was well-tolerated and safe. TRIAL REGISTRATION: clinicaltrials.gov: NCT02414841 (https://clinicaltrials.gov/ct2/show/NCT02414841).

Endovenous laser treatment of varicose veins.

Endovenous laser treatment (EVLT) has become a standard therapy for the treatment of superficial venous insufficiency. It offers a rapid, office-based therapy with minimal patient downtime and an easier recovery than traditional surgical treatment. EVLT is effective and durable and can successfully treat saphenous truncal insufficiency and accessory branches with low complication rates. EVLT can increase patient satisfaction and enable the treatment of a wider variety of patients with a more efficient procedure compared with traditional techniques.

Foam sclerotherapy for the treatment of superficial venous insufficiency.

Foam sclerotherapy has been refined over the past decade to become a safe and effective treatment for varicose veins and venous insufficiency. Using duplex ultrasound guidance, it can be used to treat large and small varicosities, saphenous trunks, incompetent perforating veins, and venous stasis ulcerations. Serious complications are rare, and in experienced hands, efficacy rivals that of traditional surgical ligation and stripping. Disadvantages of the technique are the need in many cases for more than one treatment session, and lack of US Food and Drug Administration approval of all currently available sclerosants. Foam sclerotherapy offers advantages of low cost, quick patient recovery, and ease of use; as such, it is an important tool for modern vein treatment.

Endovenous laser treatment of the small [corrected] saphenous vein: efficacy and complications.

OBJECTIVE: The study was conducted to assess the efficacy and rate of complications of endovenous laser treatment (EVLT) of the short saphenous vein (SSV). METHODS: During a 17-month period, 210 (187 patients) with SSV incompetence documented by duplex ultrasound studies were treated with EVLT using a 980-nm diode laser. Duplex ultrasound examinations were performed on the day of the procedure, within the first week, and 2 to 11 months after the procedure (mean follow-up, 4 months). Clinical examinations were performed at 2 weeks and 6 weeks. Patients were assessed for deep venous thrombosis (DVT), nerve injury, and resolution of symptoms. RESULTS: All procedures were technically successful, and in the 126 patients (60%) who completed final follow-up scanning, 96% of SSVs remained closed. Three patients (1.6%) had numbness at the lateral malleolus at the 6-week follow-up. DVT, defined as a tail of thrombus protruding into the popliteal vein, was not detected in any limbs at the initial duplex study, but was noted in 12 limbs (5.7%) at the 1-week follow-up examination. Nine patients were treated with 3 days to 3 months of fractionated heparin and Coumadin (Bristol-Myers Squibb, Princeton, NJ), and there were no DVT extensions or pulmonary emboli. The anatomic configuration of the saphenopopliteal junction was the only factor predictive of DVT. CONCLUSIONS: Intermediate-term results of EVLT of the SSV demonstrate that the technique is effective at eliminating SSV reflux and affording symptomatic relief. The incidence of nerve injury is low, but the incidence of DVT is higher than reported for the great saphenous vein. Anatomic features of the SSV may predict patient risk for DVT.

Is early postoperative duplex scan surveillance of leg bypass grafts clinically important?

PURPOSE: The typical leg bypass surveillance program begins with a duplex scan evaluation of the vein graft 3 months after surgery; studies are repeated every 3 months during the first year of follow-up and are fully reimbursed by our Medicare carrier. Some authors have recommended early (before discharge or first postoperative visit) duplex scanning to identify high-risk grafts. However, the natural history of velocity disturbances detected with early scans is unclear, and furthermore, such studies are not reimbursed by Medicare. METHODS: We reviewed all infrainguinal vein bypass grafts prospectively entered into a surveillance protocol that included an early (<6 weeks) duplex scan study. Routine completion angiography was performed at the initial operation in all patients. Early duplex scan results, the need for graft revision, and detailed follow-up of these bypass grafts were analyzed. RESULTS: Early duplex scans were performed in 224 bypass grafts placed in 204 patients. Early scans were abnormal (peak systolic velocity [PSV], >200 cm/s) in 58 grafts (26%). Six grafts of the 58 (10.3%; 2.7%) with an early abnormal duplex scan and unrepaired defects occluded during the follow-up period. Thirty grafts were revised on the basis of the initial early scan; 23 of these revisions were performed for critical or rapidly progressive lesions in the first 3 postoperative months. Seven lesions progressed more slowly and were repaired at a mean of 8 months after surgery. Interestingly, 22 flow abnormalities (37%) resolved or stabilized despite a PSV of more than 300 cm/s in six cases (27%). Clear duplex scan evidence of regression or progression of these early flow abnormalities occurred within 3 months in 51/58 cases (88%). A total of 68 grafts (30%) were revised during the entire study period; 30 of these (44%) were on the basis of the early abnormal scan. CONCLUSION: Despite normal completion arteriography, early graft velocity abnormalities are strikingly common and were detected in 26% of the 224 infrainguinal vein grafts in this series. These lesions were clinically important because 52% necessitated revision. Surprisingly, however, 38% of these early flow disturbances resolved, despite a PSV of more than 300 cm/s in 27% of cases. Early duplex scan surveillance singularly detects a clinically significant subgroup of grafts that need revision. The possible origin of these early lesions deserves further inquiry, but on the basis of its clinical yield, we recommend that early duplex scan surveillance of infrainguinal bypass grafts should be routine and should be considered for Medicare reimbursement.