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AVMs – How I Treat Them: Alcohol
Wayne F. Yakes, M.D.
Arteriovenous malformations (AVMs) constitute some of the most difficult diagnostic and therapeutic dilemmas in the practice of medicine. The clinical can range from an asympto- matic birthmark to life-threatening congestive heart failure. Attributing any of these varied symptoms to a vascular malformation can be chal enging to the most experienced clinician. Compounding the problem is the relative rarity of these lesions. If a physician encounters one patient with this condition every few years, it is difficult to develop sufficient experience for diagnosis and optimal treatment. Typical y, these patients seek help from a number of physicians, only to experience disappointing outcomes, complications, and recurrence or deterioration of their presenting symptoms. Here we present our approach to the diagnosis and their treatment with ethanol endovascu- A thorough clinical exam and history can usual y establish the diagnosis of pediatric he- mangioma or vascular malformation. Hemangiomas are usual y not present at birth and have a bright scarlet color that gradual y deepens. Vascular malformations have a persis- tent color depending on the dominant arterial, capil ary, venous or lymphatic component. Evaluating for skeletal abnormalities, abnormal veins, arterial abnormalities, pulsatility or non-pulsatility of a lesion, dependent swel ing or flattening upon elevation and disparity of limb size, along with neurologic evaluation and a good history can frequently enable diag- nose and even categorization of a vascular malformation. The Nicoladoni-Branham test of in-flow arterial occlusion, if positive, wil result in a reflex bradycardia if the AVM is of such a high flow that it is causing cardiac consequences. Color Doppler Imaging (CDI) is an essential tool in the diagnostic workup of AVMs. Accu- rate measurements of flow volumes (a calculated physiologic parameter) and resistive in- dexes can be very helpful not only in the initial evaluation but are important noninvasive pa- rameters for fol ow-up after therapy. Documentation of decreased arterial flow volumes and normalization of the resistive indexes are very specific and may obviate the need for repeti- Magnetic resonance (MR) imaging has replaced CT in the evaluation of vascular malforma- tions. It has proven to be a mainstay in the initial diagnostic evaluation as wel as in assess- ing the efficacy of endovascular therapy. MR can distinguish accurately between high-flow and low-flow malformations as wel . And the relationship to adjacent anatomic structures, such as muscles, nerves, organs, are easily determined. High-flow malformations typical y demonstrate signal void on most sequences. On gradient-echo sequences, increased sig- nal within the vascular structures is present. At fol ow-up, MR can accurately determine re- sidual areas of AVM as wel as those areas that have been treated.[2] After the diagnosis has been established, the next major decision is to determine whether therapy is warranted. The interventional radiologist should plan and direct the patient’s care with surgical specialists who are familiar with AVM management and the problems they pre- sent with, must be available. It is extremely important that appropriate surgical, medical, pediatric, and anesthesiology specialists and subspecialists be involved for optimal patient With the use of intravascular ethanol, pain control is a significant problem. Anesthesiolo- gists can greatly aid in solving this problem and determine whether general anesthesia or intravenous (IV) sedation is required for the procedure. This leaves the interventional radi- ologist free to concentrate on the case at hand. For children, general anesthesia is re- In patients with large AVMs, as opposed to smal lesions, Swan-Ganz and arterial line moni- toring are performed. Pulmonary artery pressures are consistently monitored during the in- jection of absolute ethanol. Decadron (dexamethasone sodium phosphate, USP, Merck & Co., Inc., West Point, PA, USA) is given IV to al patients prior to the procedure, usual y 10 mg for adults and 3 to 10 mg for children depending on body weight. The area of vascular access, whether it is the groin, the arm, or other points of percutane- ous catheter access, is prepped and draped sterile. The area of the AVM that is to be treated percutaneously is also prepped and draped in sterile fashion. Fluoroscopy and/or CDI imaging techniques are used in those patients that require percutaneous access. De- tailed arteriography is performed to determine the angioarchitecture of the AVM, the major compartments and endovascular access to those compartments are delineated. If the pa- tients have had prior therapy, such as surgical ligations, partial resections, intraarterial coil placement, NBCA/IBCA embolization, etc, direct puncture techniques may be required. Su- perselective placement of the catheter tip or the needle tip is a requirement, only then can Ethanol be injected into the malformation and al normal vascular structures spared. In the extremities, external pneumatic blood pressure cuffs as wel as hand tied tourniquets, may be useful and necessary to cause vascular stasis within an AVM. In the chest, abdo- men, pelvis, and head and neck area, intravascular occlusion bal oons may be necessary to achieve some element of flow arrest. Arteriograms must be performed in both the nonoc- clusive and occlusive state to determine exactly the flow characteristics of the AVM so that an appropriate volume and an appropriate rate of ethanol injection may be determined. The amount of ethanol used is equal to the flow-volume characteristics of the malformation After an injection of ethanol occlusion is usual y maintained for 10 - 15 min. After this time, vascular occlusion is released and arteriograms are performed to determine if therapy is complete or further embolization is required. Frequently additional compartments of AVM wil then fil as others become thrombosed. Meticulous repetition of the previously de- The maximum volume of ethanol used in treating patients with AVMs rarely exceeds 0.5-1.0 ml/kg body weight total dose. Most patients wil tolerate these total ethanol volumes very wel . Exceeding these doses can lead to ethanol toxicity. Cardiopulmonary col apse is a very rare but dreaded sequela and pulmonary artery Swan Ganz line and arterial line moni- toring are essential to minimize the possibility of this event occurring. Once pulmonary ar- tery pressures begin to rise, it is best to wait and not inject any more ethanol until the pul- monary pressures begin to normalize. If pulmonary artery pressures become pathological y high, the infusion of nitroglycerin, adenosine, or prostaglandin E-1 through the Swan-Ganz line can lower the intrapulmonary pressures; we favor nitroglycerin. We have determined that increased pressures related to ethanol injection reaching the pulmonary artery capil ary bed may cause, in some patients, pre-capil ary spasm, which is a transient phenomenon. However, the infusion of nitroglycerin through the Swan-Ganz line is very helpful in reducing the elevated pulmonary artery pressures. After the procedure and recovery from anesthesia, patients are sent to the general hospital ward. It is unusual for patients to require intensive care. Post-operative management con- sists of IV Decadron, fluids, Inapsine (Droperidol injection, Janssen Pharmaceuticals, Inc., Titusvil e, NJ, USA) as needed to control nausea. Oral or intramuscular (IM) Toradol (Ke- torolac tromethamine, Syntex Laboratories, Inc., Palo Alto, CA, USA) by body weight is very helpful to control pain and swel ing in adult patients. Pain is unusual, however oral and IV pain medications may be given additional y, if required. Patients with GI sensitivity to ster- oids can also be placed on Zantac (Ranitidine hydrochloride, Glaxo Inc., Research Triangle Park, NC, USA) to protect against gastric or duodenal ulcer development. Patients are usu- al y observed overnight. The following morning patients with AVMs of the extremities un- dergo CDI to evaluate the presence or absence of deep vein thrombosis of the normal deep veins. This rare complication needs to be evaluated to institute appropriate treatment im- mediately. Discharge medications usual y include a tapering dose of steroids over 7 days, Zantac management to prevent ulcer development, and pain medications, if required. All patients are usual y seen 7-10 days post-discharge or sooner if any problems develop. Patients usual y exhibit focal swel ing in the area of the AVM, which in most patients wil re- solve within two weeks. In patients with lower extremity and foot AVMs, swel ing may last longer due to the fact that the leg and foot are not only dependent organs but are weight- bearing structures as wel . Usual y after 4 weeks al swel ing is resolved and the patient, is ready for fol ow-up therapy as required. After serial therapy, MR and CDI can be used to document the efficacy of therapy. CDI spectral analysis gives very accurate information in treated and untreated high-flow AVMs. AVMs demonstrate high velocity and low resistance waveforms. As the malformation seri- ally becomes ablated, the waveform wil normalize and the resistive indexes and the flow volumes that can be calculated wil become normalized as wel . MR is also an important One of the most important aspects in AVM management is the determination of whether a patient’s symptoms have been al eviated. In those patients who have no symptoms other than an increased cardiac output, Swan-Ganz line placement and calculation of cardiac output, cardiac index, and systemic vascular resistance wil be important parameters to fol- low. Current non-invasive technologies used by cardiologists to evaluate these parameters are not as accurate as placement of a Swan-Ganz line and direct measurement. Our pa- tients are evaluated with non-invasive and arteriographic studies annual y. After several years of a persistent AVM closure, non-invasive imaging modalities wil usual y be sufficient Various complications can occur with any interventional procedure. In patients with AVMs, complication rates greater than 10% must be expected. In our initial series, we reported a total complication rate of 30%, of which 10% were major and 20% were minor complica- tions.[3] With more experience, our complication rates have dropped to around 10%. Complication rates are related to the tissues that are being embolized. Non-target emboli- zation with ethanol wil lead to tissue necrosis, as capil ary beds of normal arteries wil be total y destroyed. Therefore, it is essential that superselective catheter positioning be achieved before ethanol can be used. Direct puncture techniques may need to be per- formed in the event that the catheter cannot reach the desired position to treat only malfor- Vascular spasm, edematous tissues, and venous thrombosis can lead to complications as wel . Localized skin blisters may occur. This is usual y a minor annoyance that heals un- eventful y. Injury to adjacent muscles, organs or other tissues is possible. In the pelvis, the colon is the most sensitive organ and great care must be taken against non-target emboliza- tion to avoid localized infarction. In only 1 patient in our series has this occurred, where a patient had to have a diverting colostomy to put the injured segment at rest. It was felt that this injury may have been related to vascular spasm whereby the AVM was intimately in- volved with the superior hemorrhoidal artery. Motor or sensory nerve injuries may occur as wel . We have found that most injuries have been related to the swel ing involved with resultant nerve compression, rather than non- target embolization of the vasa nervorum. Again, aggressive Decadron therapy wil be es- sential to minimize the effects of this swel ing and to al ow the nerve to recover more quickly. It is unusual for nerve injuries to become permanent. Involvement of the appropriate clinical specialist in the management of complications is es- sential to minimize the morbidity of that complication. Those patients who present with tis- sue necrosis, whether related to arterial steal phenomenon or venous hypertension must be counseled that treatment of the AVM may not reverse their necrotic process. In those pa- tients who develop ischemic complications, particularly of the digits, this process can be halted, but may come too late to save that digit. What is important therefore is to treat the malformation to prevent further tissue loss. Bleeding is an uncommon complication of AVM’s, unlike those of the brain and spinal cord, whose propensity to bleed is their main presenting symptom. In the periphery, AVMs wil cause bleeding only if they involve the alimentary canal or if they cause superficial tissue ulceration. In this situation, the malformation requires primary treatment. Only then wil the tissues become normal, heal, and discontinue the hemorrhagic process. Attempts at skin grafting without treating the underlying malformation are usual y doomed to fail. AVMs are congenital vascular lesions typified by hypertrophied in-flow arteries and shunting through a primitive vascular nidus and into tortuous dilated out-flow veins. No intervening capil ary bed is present. Symptoms are usual y referable to the location of the AVM. The larger and more central y located AVMs have a greater likelihood for cardiac overload. Other presenting symptoms include pain, progressive nerve deterioration or palsy, disfigur- ing mass, tissue ulceration, hemorrhage, impairment of limb function and, limiting claudica- Vascular anomalies were first treated by surgeons. The early rationale of proximal arterial ligation proved total y futile as neovascular recruitment reconstituted arterial in-flow to the AVM nidus. Micro-fistulous connections became macro-fistulous feeders. Complete extir- pation of an AVM nidus proved difficult and extremely hazardous ending in many suboptimal partial resections. Partial resection could produce initial clinical improvement, but over time the patient’s symptoms recurred or worsened[3-8]. Because of the significant blood loss that frequently accompanied surgery, the skil s of interventional radiologists were eventually em- ployed to embolize these lesions preoperatively. It was hoped that a more complete resec- tion could result. However, AVM surgery stil proved extremely difficult and total removal was rarely possible. As catheter delivery systems and embolic agents improved, emboliza- tion has since emerged as a primary mode of therapy in the management of AVMs. In many cases, vascular malformations are in anatomical y and surgical y difficult or inaccessi- ble areas; this has led to increased reliance on interventional radiology to manage these le- According to D. Emerick Szilagyi, M.D., former editor of the (USA) Journal of Vascular Sur- gery, “. with few exceptions, their (AVMs) cure by surgical means is impossible. We intui- tively thought that the only answer of a surgeon to the problem of disfiguring, often noisome, and occasional y disabling blemishes and masses, prone to cause bleeding, pain, or other unpleasantness, was to attack them with vigor and with the determination of eradicating them. The results of this attempt at radical treatment were disappointing.”[4] Indeed, of 82 patients seen in this patient series, only 18 patients were deemed operable. And of these 18 patients operated upon, 10 patients were improved, 2 remained unchanged and 6 were Many endovascular occlusive agents (embolic agents) are currently in use to treat AVMs. Agents include autologous clot, gelfoam, polyvinyl alcohol particles (PVA), the various me- tal ic coils with or without fibers, tissue adhesives (IBCA/NBCA), detachable bal oons, Ethi- bloc, Sotradecol and ethyl alcohol [9-18]. It is wel known that gelfoam, PVA, coils, or de- tachable bal oons rarely cure peripheral AVMs. Ethibloc has primarily been used for venous malformation management and is uncommon for high-flow AVM’s. The tissue adhesives (IBCA/NBCA) were initial y thought to be permanent occluding agents. However, there is difficulty in their use and it is now wel documented that recanalizations do occur[12,18]. As polymerization occurs, the cyanoacrylates generate heat which may contribute to some level of histotoxicity in the adjacent area and angionecrosis. Once solidified intravascularly, the cyanoacrylates incite a mild inflammatory response. In the head and neck area, unde- sirable cosmetic results may occur from black tantalum powder used to opacify cyanoacry- lates. Furthermore, hard acrylate masses in muscular structures can cause muscular dys- function, and tissue erosions. Miscalculations with the polymerization time can lead to dis- aster, with too distal or too proximal a polymerization and solidification. Liquid sclerosing agents include sotradecol and ethanol. Sotradecol, available in a 1% or 3% aqueous solution, has a soapy texture and contains 2% benzyl alcohol. Toxicities and complications with larger injections have not been documented. Ethanol is a sclerosing agent whose metabolism and excretion in humans in wel known. We have treated many sotradecol failures and were successful in the treatment of AVMs with the use of ethanol. In our opinion, ethanol is the more effective and superior liquid sclerosing agent[3,19-26]. Ethanol induces thrombosis by denaturing blood proteins, dehydrating vascular endothelial cel s and precipitating their protoplasm, denuding the vascular wal total y of endothelial cel s, and segmental y fracturing the vascular wal to the level of the internal elastic lamina. Any one of these events, and especial y the combination of al these factors, causes an acute thrombosis. Again, extreme caution and superselective placement are required when using ethanol as an endovascular occlusive agent. In the treatment of AVMs, ethanol has demonstrated its curative potential, as opposed to pal iation, which is commonly seen with al other embolic agents. One of the factors that may lead to the permanence demonstrated by ethanol on long-term fol ow-up is the fact that the endothelial cel of the vascular wal is total y obliterated. It has not been unequivocal y proven but we have much indirect evi- dence, that endothelial cel s mediate vascular recanalization by activating a cel ular re- sponse to remove thrombus and embolic debris. Endothelial cel s then line the new chan- nels in the recanalization process. With regards to angiogenesis factors and neovascular recruitment/stimulation, it is also felt that endothelial cel s mediate this response by the re- lease of angiogenesis factors. Again, these concepts are theoretical at this point. Since ethanol completely destroys the endothelial cel , the phenomenon of recanalization are noticeably absent. The permanence encountered with ethanol is unusual with other Because cure is possible by endovascular procedures, the role of surgery for AVMs has di- minished. If cure is not possible by embolization, then either repeated transcatheter proce- dures and/or surgery may stil have a role. With current fluoroscopic systems, vessels smal er than 1 mm can be imaged. This al ows planning to spare normal structures and embolize the AVM nidus superselectively. Vascular malformations are best treated where these patients are seen on a regular basis. The interventional radiologist who occasional y evaluates a few patients every year or so wil never gain enough experience to manage these chal enging lesions effectively. All too fre- quently, the patient ultimately pays for the interventional radiologist’s initial enthusiasm, in- experience, fol y, and lack of necessary clinician back up. To optimal y manage these pa- tients, a dedicated team should be in place. Interventional radiology and the various surgi- cal and medical specialties function together, much like the tumor board team of specialists. When patients are seen and treated regularly, then experience can be gained, rational deci- sions can be made, complications can be appropriately managed, and patient care is opti- mized. It cannot be emphasized enough that, as a group, vascular malformations pose one of the most difficult chal enges in the practice of medicine. A cavalier approach to their management wil always lead to significant complications and dismal patient outcomes. Yakes WF, Stavros AT, Parker SH, Luethke JM, Rak KM, Dreisbach JN, Slater DD, Burke BJ, Chantelois AE Color doppler imaging of peripheral high-flow vascular mal- formations before and after ethanol embolotherapy. RSNA Presentation. Radiology Rak KM, Yakes WF, Ray RL, Dresibach JM, Parker SH, Luethke JM, Stavros AT. MR imaging of symptomatic peripheral vascular malformations. AJ 1992;159:107-112 Yakes WF, Haas DK, Parker SH, Gibson MD, Hopper KD, Mul igan JS, Pevsner PH, Johns JC Jr, Carter TE. Symptomatic vascular malformations: Ethanol embolother- Szilagyi DE, Smith RF, Elliott JP, Hageman JH. Congenital arteriovenous anomalies of the limbs. Arch Surg 1976;111:423-429 Decker DG, Fish CR, Juergens JL. Arteriovenous fistulas of the female pelvis: A di- agnostic problem. Obstet Gynecol 1968;31:799-805 Flye MW, Jordan BP, Schwartz MZ. 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AJNR 1989;10:135-141: Yakes WF, Pevsner PH, Reed MD, Donohue HJ, Ghaed M. Serial embolizations of an extremity arteriovenous malformation with alcohol via direct percutaneous punc- Takebayaski S, Hosaka M, Ishizuka E, Hirokawa M, Matsui K. Arteriovenous mal- formations of the kidneys: Ablation with alcohol. AJR 1988;150:587-590 Vinson AM, Rohrer DB, Wil cox CW, Sigfred SV, Wheeler JR, Jacobs JS, Ruffin W Jr. Absolute ethanol embolization for peripheral arteriovenous malformation: Report of two cures. South Med J 1988;1:1052-1055 Yakes WF, Haas DK, Parker SH, Gibson MD, Hopper KD, Mul igan JS, Pevsner PH, Johns JR Jr., Carter TE. Alcohol embolotherapy of vascular malformations. Semin Yakes WF, Luethke JM, Parker SH, Stavros AT, Rak KM, Hopper KD, Dreisbach JN, Griffin DJ, Seibert CE, Carter TE, Guil iland JD. Ethanol embolization of vascular malformations. 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Diagnosis and Management of Venous Malformations. In “Venous Inter- ventional Radiology with Clinical Perspectives”, Savader SJ and Trerotola SO, edi- tors. Thieme Medical Publishers, Inc., New York 1996; pp 139-150. Yakes WF, Rossi P, Odink H. Arteriovenous Malformation Management: How I Do It. Cardiovasc Intervent Radiol 1996;19:65-71. Keljo DJ, Yakes WF, Andersen JM, Timmons CF. Recognition and Treatment of Ve- nous Malformations of the Rectum. J Pediatr Gastroenterol Nutr 1996;23:442-446. Yakes WF, Krauth L, Ecklund J, Swengle R, Dreisbach JN, Seibert CE, Baker R, Mil er M, VanderArk G, Ful agar T, Prenger E. Ethanol Endovascular Management of Brain AVMs: Initial Results. Neurosurgery 1997;40:1145-1154. Ethanol Endovascular Management of Brain Arteriovenous Malformations: Initial Ex- perience. Interventional Neuroradiology Strategies and Practical Techniques. Con- nors and Wojak, editors. W.B. Saunders CO., Philadelphia. Chapter 22. In Press 34. Management of Extracranial Head and Neck and Paraspinal Vascular Malformations. Interventional Neuroradiology Strategies and Practical Techniques. Connors and Wo- jak, editors. W.B. Saunders CO., Philadelphia. Chapter 27. In Press 1998.

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