Detergent Sclerosants Stimulate Leukocyte Apoptosis and Oncosis.

OBJECTIVE/BACKGROUND: The objective was to investigate the effects of the detergent sclerosants sodium tetradecyl sulfate (STS) and polidocanol (POL) on human leukocytes at sublytic concentrations. METHODS: Leukocytes were isolated and labelled with antibodies to assess for apoptosis and examined with confocal microscopy and flow cytometry. Isolated leukocyte count and viability was assessed using trypan blue, and propidium iodide staining. Phosphatidylserine (PS) exposure, a universal hallmark to measure cell apoptosis, was identified by flow cytometry using lactadherin. Caspases 3, 8, and 9, and Bax activation, as well as inhibitory assays with pan-caspase (Z-VAD-FMK) and Bax (BI-6C9) were assessed to determine apoptotic pathways. Porimin activation was used to assess cell permeability. RESULTS: Up to 40% of leukocytes maintained membrane integrity at sublytic concentrations (≤0.15%) of sclerosants. The remaining 60% did not maintain membrane integrity but were not completely lysed. PS exposure was increased with both STS and POL exhibiting a dose- and time-dependant trend. While activation of caspases 3, 8, and 9, as well as Bax activation, were increased in leukocytes stimulated with low concentrations of STS, only caspases 3 and 9 and Bax were increased with POL. Inhibitory assays demonstrated caspases 3, 8, and 9, and Bax inhibition at low concentrations with both STS and POL. Both agents increased the leukocyte activation of porimin at all concentrations. On confocal microscopy, stains for caspases 3, 8, and 9, and Bax were increased for both STS and POL. Porimin stain was markedly positive for both STS and POL. CONCLUSION: Both sclerosants induced leukocyte apoptosis at sublytic concentrations. STS activated both extrinsic and intrinsic pathways of apoptosis, while POL stimulated the intrinsic pathway of apoptosis only. Both agents induced oncosis. Based on these results, STS appears to have a greater effect than POL.

Morphological changes in vascular and circulating blood cells following exposure to detergent sclerosants.

OBJECTIVES: To investigate morphological changes in vascular and circulating blood cells following exposure to detergent sclerosants sodium tetradecyl sulfate and polidocanol. METHODS: Samples of whole blood, isolated leukocytes, platelets, endothelial cells, and fibroblasts were incubated with varying concentrations of sclerosants. Whole blood smears were stained with Giemsa and examined by light and bright field microscopy. Phalloidin and Hoechst stains were used to analyze cytoplasmic and nuclear morphology by fluorescence microscopy. Endothelial cell and fibroblasts were analyzed by live cell imaging. RESULTS: Higher concentrations of sclerosants induced cell lysis. Morphological changes in intact cells were observed at sublytic concentrations of detergents. Low concentration sodium tetradecyl sulfate induced erythrocyte acanthocytosis and macrocytosis, while polidocanol induced Rouleaux formation and increased the population of target cells and stomatocytes. Leukocytes showed swelling, blebbing, vacuolation, and nuclear degradation following exposure to sodium tetradecyl sulfate, while polidocanol induced pseudopodia formation, chromatin condensation, and fragmentation. Platelets exhibited pseudopodia with sodium tetradecyl sulfate and a "fried egg" appearance with polidocanol. Exposure to sodium tetradecyl sulfate resulted in size shrinkage in both endothelial cell and fibroblasts, while endothelial cell developed distinct spindle morphology. Polidocanol induced cytoplasmic microfilament bundles in both endothelial cell and fibroblasts. Patchy chromatin condensation was observed following exposure of fibroblasts to either agent. CONCLUSION: Detergent sclerosants are biologically active at sublytic concentrations. The observed morphological changes are consistent with cell activation, apoptosis, and oncosis. The cellular response is concentration dependent, cell-specific, and sclerosant specific.

Detergent sclerosants are deactivated and consumed by circulating blood cells.

OBJECTIVE: To investigate the deactivating effects of circulating blood cells on the lytic activity of detergent sclerosants. METHODS: Samples of whole blood (WB), platelet-rich plasma (PRP), and isolated leukocytes were incubated with various concentrations of sodium tetradecyl sulfate (STS) or polidocanol (POL) and added to human umbilical vein endothelial cells (HUVECs), which were then counted using a fluorescent plate reader. Full blood counting was performed using a hematology analyzer. Platelet lysis and microparticle formation was assessed using lactadherin binding in flow cytometry. RESULTS: Detergent sclerosant activity was decreased in WB when compared with plasma and saline controls. The sclerosant lytic activity on endothelial cells was increased 23-fold for STS and 59-fold for POL in saline controls compared with WB. At high concentrations, sclerosants lysed erythrocytes, leukocytes, and platelets. Platelets were more sensitive to the lytic activity of sclerosants than other cell types. Neutrophils were the most susceptible of all leukocytes to the lytic activity of sclerosants. The presence of erythrocytes and leukocytes in samples decreased the lytic activity of sclerosants. Sclerosants at all concentrations induced erythrocyte-derived microparticle formation. CONCLUSIONS: Detergent sclerosants are consumed and deactivated by circulating blood cells. This deactivating effect is above and beyond the neutralizing effects of plasma proteins and contributes to the overall neutralizing effect of blood. Different blood cell types exhibited varying levels of vulnerability to the lytic activity of sclerosants with platelets being the most and erythrocytes the least vulnerable (platelets > leukocytes > erythrocytes).

Arteries masquerading as varicose veins: A trap for phlebologists.

Ultrasound guided sclerotherapy may be complicated by intra-arterial injections resulting in significant tissue necrosis. Here, we present a 69-year-old man with a history of right small saphenous vein "stripping", presenting for the treatment of symptomatic lower limb varicose veins. Duplex ultrasound of the right lower limb outlined the pathway of venous incompetence. Despite the history of "stripping", the small saphenous vein was present but the sapheno-popliteal junction was ligated at the level of the knee crease. No other unusual findings were reported at the time. During ultrasound guided sclerotherapy, subcutaneous vessels of the right posterior calf were noted to be pulsatile on B-mode ultrasound. Treatment was interrupted. Subsequent angiography and sonography showed absence of the right distal popliteal artery. A cluster of subcutaneous vessels of the right medial and posterior calf were found to be arterial collaterals masquerading as varicose veins. Injection sclerotherapy of these vessels would have resulted in significant tissue loss. This case highlights the importance of vigilance at the time of treatment and the invaluable role of ultrasound in guiding endovenous interventions.

Stewart-Bluefarb syndrome: Report of five cases and a review of literature.

Stewart-Bluefarb syndrome is a rare angioproliferative disorder characterised by acroangiodermatitis associated with an underlying arteriovenous shunt. This condition should be differentiated from acroangiodermatitis of Mali classically described in association with chronic venous insufficiency. Patients with Stewart-Bluefarb syndrome typically present with lower leg pigmented macules, papules and plaques that can coalesce to form larger confluent patches of pigmentation. Recognition of Stewart-Bluefarb syndrome may be difficult or delayed as the cutaneous manifestations may resemble a variety of other dermatological conditions. Most commonly, acroangiodermatitis may be confused with Kaposi's sarcoma and the condition is often referred to as 'Pseudo-Kaposi's sarcoma'. Acroangiodermatitis may also resemble or coexist with pigmentation of chronic venous insufficiency. As seen in this report, acroangiodermatitis may also be clinically confused with the 'cavernous' form of a capillary malformation. Here, we describe five patients with Stewart-Bluefarb syndrome. In one female and two male patients the diagnosis was delayed as the acroangiodermatitis closely resembled other conditions. All underlying arterio-venous communications were initially diagnosed on duplex ultrasound and confirmed with magnetic resonance angiography. Four patients were found to have a congenital arterio-venous malformation while one was diagnosed with a post-thrombotic arterio-venous fistula. Management included observation and intervention using a variety of techniques including percutaneous or trans-catheter embolisation, endovenous laser, radiofrequency ablation and foam ultrasound guided sclerotherapy. This case series highlights the challenges involved in the diagnosis and management of Stewart-Bluefarb syndrome. Given the local and systemic sequelae of high flow shunts, correct diagnosis and early detection of the underlying arterio-venous abnormality is crucial in the long-term management of these patients and in preventing the associated complications.

Diagnosis and Treatment of Venous Malformations. Consensus Document of the International Union of Phlebology (IUP): updated 2013.

Venous malformations (VMs) are the most common vascular developmental anomalies (birth defects) . These defects are caused by developmental arrest of the venous system during various stages of embryogenesis. VMs remain a difficult diagnostic and therapeutic challenge due to the wide range of clinical presentations, unpredictable clinical course, erratic response to the treatment with high recurrence/ persistence rates, high morbidity following non-specific conventional treatment, and confusing terminology. The Consensus Panel reviewed the recent scientific literature up to the year 2013 to update a previous IUP Consensus (2009) on the same subject. ISSVA Classification with special merits for the differentiation between the congenital vascular malformation (CVM) and vascular tumors was reinforced with an additional review on syndrome-based classification. A "modified" Hamburg classification was adopted to emphasize the importance of extratruncular vs. truncular sub-types of VMs. This incorporated the embryological ongm, morphological differences, unique characteristics, prognosis and recurrence rates of VMs based on this embryological classification. The definition and classification of VMs were strengthened with the addition of angiographic data that determines the hemodynamic characteristics, the anatomical pattern of draining veins and hence the risk of complication following sclerotherapy. The hemolymphatic malformations, a combined condition incorporating LMs and other CVMs, were illustrated as a separate topic to differentiate from isolated VMs and to rectify the existing confusion with name-based eponyms such as Klippei-Trenaunay syndrome. Contemporary concepts on VMs were updated with new data including genetic findings linked to the etiology of CVMs and chronic cerebrospinal venous insufficiency. Besides, newly established information on coagulopathy including the role of D-Dimer was thoroughly reviewed to provide guidelines on investigations and anticoagulation therapy in the management of VMs. Congenital vascular bone syndrome resulting in angio-osteo-hyper/hypotrophy and (lateral) marginal vein was separately reviewed. Background data on arterio-venous malformations was included to differentiate this anomaly from syndromebased VMs. For the treatment, a new section on laser therapy and also a practical guideline for follow up assessment were added to strengthen the management principle of the multidisciplinary approach. All other therapeutic modalities were thoroughly updated to accommodate a changing concept through the years.

Guideline. Diagnosis and treatment of venous malformations. consensus document of the international union of phlebology (iup): updated-2013.

Venous malformations (VMs) are the most common vascular developmental anomalies (birth defects). These defects are caused by developmental arrest of the venous system during various stages of embryogenesis. VMs remain a difficult diagnostic and therapeutic challenge due to the wide range of clinical presentations, unpredictable clinical course, erratic response to the treatment with high recurrence/persistence rates, high morbidity following nonspecific conventional treatment, and confusing terminology. The Consensus Panel reviewed the recent scientific literature up to the year 2013 to update a previous IUP Consensus (2009) on the same subject. ISSVA Classification with special merits for the differentiation between the congenital vascular malformation (CVM) and vascular tumors was reinforced with an additional review on syndrome-based classification. A "modified" Hamburg classification was adopted to emphasize the importance of extratruncular vs. truncular subtypes of VMs. This incorporated the embryological origin, morphological differences, unique characteristics, prognosis and recurrence rates of VMs based on this embryological classification. The definition and classification of VMs were strengthened with the addition of angiographic data that determines the hemodynamic characteristics, the anatomical pattern of draining veins and hence the risk of complication following sclerotherapy. The hemolymphatic malformations, a combined condition incorporating LMs and other CVMs, were illustratedas a separate topic to differentiate from isolated VMs and to rectify the existing confusion with namebased eponyms such as Klippel-Trenaunay syndrome. Contemporary concepts on VMs were updated with new data including genetic findings linked to the etiology of CVMs and chronic cerebrospinal venous insufficiency. Besides, newly established information on coagulopathy including the role of D-Dimer was thoroughly reviewed to provide guidelines on investigations and anticoagulation therapy in the management of VMs. Congenital vascular bone syndrome resulting in angio-osteo-hyper/hypotrophy and (lateral) marginal vein was separately reviewed. Background data on arterio-venous malformations was included to differentiate this anomaly from syndrome-based VMs. For the treatment, a new section on laser therapy and also a practical guideline for follow up assessment were added to strengthen the management principle of the multidisciplinary approach. All other therapeutic modalities were thoroughly updated to accommodate a changing concept through the years.

Infusion of foam sclerosants results in a distance-dependent procoagulant activity, haemoconcentration and elevation of D-dimer levels.

OBJECTIVE: To investigate the biological effects of foam sclerotherapy in vivo. MATERIALS AND METHODS: Ultrasound-guided sclerotherapy was performed using a 3% sodium tetradecyl sulphate or polidocanol. A total of 15 mL of foam was injected. Samples were collected from antecubital veins, target saphenous veins and the adjoining deep veins before, immediately after and 1 hour after the procedure. Saphenous vein samples were also taken sequentially at set 15 cm intervals. Clotting times, D-dimer, cell counts and biochemical parameters were measured. D-dimer levels were repeated one week later. RESULTS: Forty procedures were performed. Systemic clotting times were not affected by the procedure. Injection of 0.5 mL of foam 5 cm away from the relevant junctions resulted in procoagulant activity in the adjoining deep veins (sodium tetradecyl sulphate) and the target saphenous veins (sodium tetradecyl sulphate and polidocanol). The procoagulant effect in the target veins reached a peak at 15 cm but normalised at 45 cm. D-dimer levels were significantly increased 1 hour after treatment with either agent and remained elevated one week later. Sodium tetradecyl sulphate and to a lesser degree polidocanol induced biochemical changes consistent with haemoconcentration. CONCLUSION: Infusion of foam sclerosants results in a distance-dependent procoagulant activity in the exposed vessels. Foam sclerotherapy results in haemoconcentration and elevation of D-dimer.

Non-involuting congenital haemangioma of the eyelid: successful treatment with fluroscopic ultrasound guided sclerotherapy and surgical excision.

We present a case of non-involuting congenital haemangioma (NICH) of the right eyelid which was present at birth as a purpuric macule but increased in size to cause significant obstruction of vision. At four years of age the lesion was treated with fluroscopic ultrasound-guided sclerotherapy using 0.5% sodium tetradecyl suphate foam and surgically debulked 16 days later. Histopathology was negative for glucose transporter-1 stain confirming the diagnosis. The residual segments were subsequently treated in three further sessions of sclerotherapy in the ensuing three years. This treatment approach resulted in a good cosmetic and functional outcome with no associated complications. To our knowledge, this is the first published case of a histologically confirmed NICH treated primarily with sclerotherapy.

Foam sclerosants are more stable at lower temperatures.

OBJECTIVES: Sclerosant foams are aqueous and break down under the influence of gravity, pressure, and temperature. The aim of this study was to investigate the effects of temperature on foam stability. METHODS: Sodium tetradecyl sulphate (STS) and polidocanol (POL) liquid and foam (1 + 4, liquid-plus-air fraction) were investigated in a range of concentrations (0.5%, 1.5%, 3.0%) and temperatures. Surface tension was measured by the Du Nuoy ring method. Liquid drainage from foam was measured and documented by serial photography. Both pre- and post-cooling variations were investigated. RESULTS: Surface tension decreased at higher temperatures. Surface tension of POL was higher than STS at concentrations tested. POL foam half-time increased significantly at higher concentrations while the half-time of STS foam was not affected by concentration. Heating the sclerosant foam above the ambient temperature reduced its half-time while cooling below the ambient temperature prolonged the half-time. Both pre- and post-cooling of the foams resulted in significant prolongation of half-times when compared to no cooling. Maximum stability of the two sclerosant foams tested was achieved at 10 °C. CONCLUSIONS: Foam sclerosants are more stable at cooler temperatures.

Sclerosant foam structure and stability is strongly influenced by liquid air fraction.

OBJECTIVES: To determine the effects of sclerosant foam preparation and composition on foam structure, the time course of liquid drainage, and foam coarsening. METHODS: Sodium tetradecyl sulphate (STS) and polidocanol (POL) foams were investigated in a range of concentrations (0.5-3%) and liquid-plus-air fractions (LAF; 1 + 2 to 1 + 8). Foam was injected into a vein simulation model (polyvinyl chloride tubing, inner diameter 3 mm, constant pressure 5-7 mmHg) filled with saline or blood. Liquid drainage, bubble count, and diameter were measured and documented by serial photography. RESULTS: Liquid drainage was faster in the vertical position than the horizontal one. In all variations, very small bubbles (diameter <30 µm) were generated initially that coarsened to form micro-foams (<250 µm). By 3 minutes mini-foams (>250 µm) and by 7.5 minutes macro-foams (>500 µm) were formed. Following injection, the upper regions of foam coarsened faster as liquid drained to the bottom of the vessel. Wet preparations produced significantly smaller bubbles. Low concentration POL foam produced significantly higher bubble counts and coarsened slower than STS. CONCLUSIONS: Foam structure is strongly influenced by the LAF. Despite the initial formation of micro-bubbles in the syringe, mini- and macro-bubbles are formed in target vessels with time post-injection.

Consensus Document of the International Union of Angiology (IUA)-2013. Current concept on the management of arterio-venous management.

Arterio-venous malformations (AVMs) are congenital vascular malformations (CVMs) that result from birth defects involving the vessels of both arterial and venous origins, resulting in direct communications between the different size vessels or a meshwork of primitive reticular networks of dysplastic minute vessels which have failed to mature to become 'capillary' vessels termed "nidus". These lesions are defined by shunting of high velocity, low resistance flow from the arterial vasculature into the venous system in a variety of fistulous conditions. A systematic classification system developed by various groups of experts (Hamburg classification, ISSVA classification, Schobinger classification, angiographic classification of AVMs,) has resulted in a better understanding of the biology and natural history of these lesions and improved management of CVMs and AVMs. The Hamburg classification, based on the embryological differentiation between extratruncular and truncular type of lesions, allows the determination of the potential of progression and recurrence of these lesions. The majority of all AVMs are extra-truncular lesions with persistent proliferative potential, whereas truncular AVM lesions are exceedingly rare. Regardless of the type, AV shunting may ultimately result in significant anatomical, pathophysiological and hemodynamic consequences. Therefore, despite their relative rarity (10-20% of all CVMs), AVMs remain the most challenging and potentially limb or life-threatening form of vascular anomalies. The initial diagnosis and assessment may be facilitated by non- to minimally invasive investigations such as duplex ultrasound, magnetic resonance imaging (MRI), MR angiography (MRA), computerized tomography (CT) and CT angiography (CTA). Arteriography remains the diagnostic gold standard, and is required for planning subsequent treatment. A multidisciplinary team approach should be utilized to integrate surgical and non-surgical interventions for optimum care. Currently available treatments are associated with significant risk of complications and morbidity. However, an early aggressive approach to elimiate the nidus (if present) may be undertaken if the benefits exceed the risks. Trans-arterial coil embolization or ligation of feeding arteries where the nidus is left intact, are incorrect approaches and may result in proliferation of the lesion. Furthermore, such procedures would prevent future endovascular access to the lesions via the arterial route. Surgically inaccessible, infiltrating, extra-truncular AVMs can be treated with endovascular therapy as an independent modality. Among various embolo-sclerotherapy agents, ethanol sclerotherapy produces the best long term outcomes with minimum recurrence. However, this procedure requires extensive training and sufficient experience to minimize complications and associated morbidity. For the surgically accessible lesions, surgical resection may be the treatment of choice with a chance of optimal control. Preoperative sclerotherapy or embolization may supplement the subsequent surgical excision by reducing the morbidity (e.g. operative bleeding) and defining the lesion borders. Such a combined approach may provide an excellent potential for a curative result. Conclusion. AVMs are high flow congenital vascular malformations that may occur in any part of the body. The clinical presentation depends on the extent and size of the lesion and can range from an asymptomatic birthmark to congestive heart failure. Detailed investigations including duplex ultrasound, MRI/MRA and CT/CTA are required to develop an appropriate treatment plan. Appropriate management is best achieved via a multi-disciplinary approach and interventions should be undertaken by appropriately trained physicians.

Complications of foam sclerotherapy.

Foam sclerotherapy may result in drug and/or gas-related complications of a generalized or localized nature. Significant complications include anaphylactic/anaphylactoid reactions (very rare), deep vein thrombosis (1-3%), stroke (0.01%), superficial venous thrombosis (4.4%), tissue necrosis (variable frequency), oedema (0.5%) and nerve damage (0.2%). Cosmetic complications include telangiectatic matting (15-24%) and pigmentation (10-30%). Patent foramen ovale and other cardio-pulmonary right-to-left shunts seem to play a role in the systemic gas-related complications. In conclusion, foam sclerotherapy is characterized by an overall high degree of safety, though special attention should be given to the embolic and thrombotic complications. Good technique, adequate imaging, general precautions and compliance with post-treatment instructions may help avoid some of the adverse events and an appropriate early intervention may minimize possible sequelae. Higher volumes of sclerosant foam have been attributed to local and distant thrombotic complications and should be avoided.

Paradoxical embolism, stroke and sclerotherapy.

Sclerotherapy has been associated with 13 published cases of stroke since 1994. Four earlier reports implicated liquid sclerosants while nine recent cases have followed foam sclerotherapy. This adverse event represents a very rare complication of a very popular procedure. Ten of the 13 reported patients recovered completely with no long-term sequelae. A right-to-left shunt and in particular a patent foramen ovale (PFO) was the most consistent risk factor. Paradoxical gas emboli were observed in the brain-supplying or the intra-cranial arteries of five patients with an immediate onset of stroke after foam sclerotherapy. Paradoxical clot embolism was suspected in three patients with a delayed onset of stroke and concurrent venous thrombosis. In the remaining five cases, which included two cases with an immediate onset after liquid sclerotherapy, no specific cause was identified. Patients with a past history of cryptogenic stroke or a long life history of recurrent classic migraine attacks (with aura) have a higher risk of neurological adverse events and may benefit from preoperative screening and percutaneous closure of PFO.

Three cases of stroke following peripheral venous interventions.

We report three cases of stroke in association with peripheral venous interventions that each included foam ultrasound-guided sclerotherapy (UGS). All three female patients experienced a right middle cerebral artery (MCA) stroke causing dysphasia and left hemiparesis. A patent foramen ovale was found in each patient. The first incident occurred two days after foam UGS to treat small tributaries of a great saphenous vein (GSV). Paradoxical clot embolism was presumed in this case where concurrent deep vein thrombosis with non-occlusive thrombus in a medial gastrocnemius vein extending to the popliteal vein was detected on ultrasound. The second case occurred immediately at the completion of foam UGS and ambulatory phlebectomy to treat GSV tributaries. Paradoxical gas embolism was demonstrated in this patient confirmed by visualization of bubbles in the right MCA on CT angiography. The third case occurred one day after endovenous laser ablation (1470 nm) and foam UGS to treat both great and small saphenous veins. No specific cause could be confirmed in this patient. Sodium tetradecyl sulphate foam was used in all three cases (3%, 16 mL; 1.5%, 4 mL and 3%, 25 mL, respectively). All three patients recovered completely within a few days.

In vitro effects of detergent sclerosants on clot formation and fibrinolysis.

OBJECTIVE: To investigate the in vitro effects of detergent sclerosants sodium tetradecyl sulphate (STS) and polidocanol (POL) on clot formation and lysis. MATERIALS AND METHODS: clot kinetics were assessed in whole blood by thromboelastography (TEG®) and rotational thromboelastometry (ROTEM®). Fibrinogen was measured by the Clauss method in plasma and factor XIII (FXIII) by enzyme-linked immunosorbent assay (ELISA). Turbidity measurements were used to assess clot lysis in plasma, and fibrinolysis in non-cross-linked and cross-linked fibrin. D-dimer was measured by VIDAS®, STA®Liatest® and AxSYM® assays. RESULTS: Strong clots were formed at low sclerosant concentrations (0.075-0.1%). At midrange concentrations (0.15% STS, 0.15-0.3% POL), both agents inhibited the contribution of platelets to clot firmness and formed weak clots prone to lysis. At higher concentrations (STS ≥ 0.3% and POL ≥ 0.6%), clot formation was inhibited. STS destroyed FXIII at ≥ 0.15% and fibrinogen at ≥ 0.6%. Neither sclerosant had a significant effect on cross-linked fibrin, but STS had a lytic effect on non-cross-linked fibrin. STS caused an artefactual elevation of D-dimer in the VIDAS® assay when fibrinogen was present. CONCLUSION: Detergent sclerosants demonstrated a trimodal effect on clot formation, initiating strong clots at low concentrations, weak clots at midrange concentrations and preventing clot formation at higher concentrations. Neither agent had fibrinolytic activity.

Venous gas embolism during foam sclerotherapy of saphenous veins despite recommended treatment modifications.

OBJECTIVE: To investigate the effectiveness of methods proposed to prevent venous gas embolism during foam sclerotherapy. METHODS: Transthoracic echocardiography was performed concurrent with ultrasound-guided sclerotherapy (UGS) of great or small saphenous veins. A volume of 2.5 mL of 3% sodium tetradecyl sulphate foam was prepared following the Tessari method and injected slowly 5-10 cm away from saphenous junctions. The procedure was repeated with modifications including using a 5 µm filter to generate microfoam, carbon dioxide as the foaming gas, leg elevation before or after the injection and immobility post-treatment. RESULTS: Bubbles entered the right heart in less than 60 seconds and continued for up to 50 minutes despite all treatment modifications. None of the patients had a patent foramen ovale and none developed any neurological or cardiac symptoms. CONCLUSION: Bubble emboli entered the heart during foam UGS of saphenous veins despite all treatment modifications and low volumes of foam used.