Correspondence
More on Microembolism and Foam Sclerotherapy
N Engl J Med 2008; 359:656-657August 7, 2008
- Article
To the Editor:
Ceulen et al. (April 3 issue)1 found intracardiac gas emboli in all patients treated with polidocanol foam (air-to-liquid ratio, 4:1), noting the potential for microembolism. We corroborate this observation in a series of 45 patients treated with proprietary very-low-nitrogen (<0.8%) polidocanol microfoam (Varisolve) generated through a sterile canister system controlling bubble size. In our unpublished series, intracardiac gas emboli were detected in all patients.
An ongoing, multicenter investigational-new-drug (IND) trial involving patients with great-saphenous-vein incompetence and right-to-left cardiac shunts is investigating the clinical significance of gas emboli with the proprietary very-low-nitrogen microfoam. On pretreatment screening, the prevalence of right-to-left shunt was unexpectedly high (40%). During treatment, 36 patients had cerebral emboli, detected by transcranial Doppler studies, and underwent extensive monitoring, including diffusion-weighted magnetic resonance imagine (MRI) at 24 hours and 28 days. No cerebral lesions were detected, and no abnormalities were noted on perimetry or assessment of cardiac markers.2 The study will continue until 50 patients with cerebral emboli have been studied.
In contrast, the risk associated with physician-compounded room-air foams is difficult to quantify in the absence of specific data on the potential for cerebral infarction.
Janet E. Rush, M.D.
David D.I. Wright, M.B.
BTG International, West Conshohocken, PA 19428Drs. Rush and Wright report being employees of BTG International, the company developing the proprietary microfoam Varisolve under an IND application. No other potential conflict of interest relevant to this letter was reported.
2 References1
Ceulen RPM ,Sommer A ,Vernooy K . Microembolism during foam sclerotherapy of varicose veins. N Engl J Med 2008;358:1525-1526
Full Text | Web of Science | Medline2
Regan JD ,Gibson KD ,Ferris B , et al. Safety of proprietary sclerosant microfoam for saphenous incompetence in patients with R-to-L shunt: interim report. J Vasc Interv Radiol 2008;19:Suppl:S35-S35
CrossRef
Author/Editor Response
Rush and Wright confirm our report on intracardiac gas emboli in both the right and left side of the heart during foam sclerotherapy in patients with patent foramen ovale. However, we describe neurologic signs in two patients after foam sclerotherapy, whereas Rush and Wright state that none of the patients with cerebral foam emboli had neurologic symptoms or cerebral lesions on MRI.
Foam can be produced with a variety of agitation techniques that result in differences in bubble size and rate of reabsorption.1 We applied the double syringe technique, which led to larger bubbles than Rush and Wright's specifically engineered Varisolve technique to dispense foam having a highly controlled bubble-size distribution. Moreover, for polidocanol-foam preparation, Rush and Wright used a very-low-nitrogen gas mixture, whereas we used room air, which is associated with increases in bubble number and size.2 Therefore, we believe that the results of the two studies are difficult to compare.
Although we still believe that foam sclerotherapy is a safe procedure and routine screening for patent foramen ovale before foam sclerotherapy is not recommended, we also believe that further research regarding foam characteristics and consequences of foam emboli is necessary.
2 ReferencesRoeland P.M. Ceulen, M.D.
GROW School for Oncology and Developmental Biology, 6202 AZ Maastricht, the Netherlands
rpmceulen@gmail.com Kevin Vernooy, M.D., Ph.D.
Cardiovascular Research Institute Maastricht, 6200 MD Maastricht, the Netherlands1
Eckmann DM ,Kobayashi S ,Li M . Microvascular embolization following polidocanol microfoam sclerosant administration. Dermatol Surg 2005;31:636-643
CrossRef | Web of Science | Medline2
Regan JD ,Gibson KD ,Ferris B , et al. Safety of proprietary sclerosant microfoam for saphenous incompetence in patients with R-to-L shunt: interim report. J Vasc Interv Radiol 2008;19:Suppl:S35-S35
CrossRef
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LONG LI, XUAN-YANG HONG, XIN-QIAO ZENG, PEI-LIN LUO, QIONG YI. (2011) Technical Feasibility and Early Results of Radiologically Guided Foam Sclerotherapy for Treatment of Varicose Veins. Dermatologic Surgery 37:7, 992-998
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John D. Regan, Kathleen D. Gibson, Janet E. Rush, Cynthia K. Shortell, Stanley A. Hirsch, David D.I. Wright. (2011) Clinical significance of cerebrovascular gas emboli during polidocanol endovenous ultra-low nitrogen microfoam ablation and correlation with magnetic resonance imaging in patients with right-to-left shunt. Journal of Vascular Surgery 53:1, 131-137
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2011. Clinical Methods for Sclerotherapy of Varicose Veins. , 238-281.
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R.P.M. Ceulen, E.A. Jagtman, A. Sommer, G.J.J. Teule, G.W.H. Schurink, G.J. Kemerink. (2010) Blocking the Saphenofemoral Junction During Ultrasound-Guided Foam Sclerotherapy – Assessment of a Presumed Safety-measure Procedure. European Journal of Vascular and Endovascular Surgery 40:6, 772-776
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E.C. Abbott. (2009) Acronym Madness – Part 2. Canadian Journal of Cardiology 25:12, e430-e431
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T. M. Leslie-Mazwi, Laura L. Avery, John R. Sims. (2009) Intra-arterial Air Thrombogenesis after Cerebral Air Embolism Complicating Lower Extremity Sclerotherapy. Neurocritical Care 11:2, 247-250
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T. M. Leslie-Mazwi, Laura L. Avery, John R. Sims. (2009) Intra-arterial Air Thrombogenesis after Cerebral Air Embolism Complicating Lower Extremity Sclerotherapy. Neurocritical Care 11:1, 97-100
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(2009) Current awareness: Pharmacoepidemiology and drug safety. Pharmacoepidemiology and Drug Safety 18:1, i-xiv
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