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TAKAYASU'S ARTERITIS
A nonspecific arteritis affecting the thoracic and abdominal aorta and its major branches, Takayasu's disease was described by a Japanese ophthalmologist in l908. Although uncommon in the United States, it is often seen in Asia and usually affects young females. It has also been described in older women and males, and the natural history of the disorder has been carefully documented. The arteritis involves all layers of the arterial wall, with proliferation of connective tissue and degeneration of the elastic fibers, and may also involve the pulmonary arteries. Granulomatous lesions may be present with associated fusiform or saccular aneurysms. Three types of this disorder are now recognized .
Takayasu's disease is first characterized by fever, malaise, arthritis, and arthralgia. Pericardial pain, tachycardia, and vomiting may also occur. It has been suggested that the disorder may be an autoimmune disease, 8 and corticosteroids may be beneficial. The later manifestations are those of ischemia of both the cerebral and upper extremity circuits.
The long-term outcome in 120 patients with this disorder is reviewed with statistical analyses of related prognostic factors. Negative factors affecting outcome included retinopathy, hypertension, aortic regurgitation, the presence of an aneurysm, and a progressive clinical course. The overall survival at 15 years was 83%. 6 Surgical treatment of Takayasu's arteritis may prove disappointing, because the endarterectomy site and grafts are likely to reocclude later. Revascularization is recommended in appropriate patients, including those with aortic regurgitation, coronary stenosis, and aortic aneurysms. Replacement of the aortic valve and coronary bypass can yield good results.
In a collected series of 63 patients with 92 coronary lesions undergoing coronary artery bypass procedures, coronary ostial lesions were present in 73%. In this group, there were five early and three late deaths in the 63 patients.
THROMBOTIC OBLITERATION OF THE ABDOMINAL AORTA AND ILIAC ARTERIES (LERICHE'S SYNDROME)
Chronic occlusion of the aortic bifurcation by thrombosis was originally described by Leriche in French in 1923. In 1948, Leriche and Morel wrote an excellent review in English. Leriche emphasized that the disorder is a chronic one and is associated with a specific symptom complex. It typically affects men 35 to 60 years of age.
CLINICAL MANIFESTATIONS
Characteristic symptoms of thrombotic occlusion of the terminal aorta include (1) extreme liability to fatigue of both lower limbs, described as a weariness rather than the typical intermittent claudication; (2) symmetrical atrophy of both lower limbs without trophic changes in the skin or nails; (3) pallor of the legs and feet; and (4) inability to maintain a stable erection due to inadequate arterial flow to the penis from hypogastric arterial obstruction, thus reducing the blood flow through the internal pudendal artery and its blood flow to the corpora cavernosa. The physical findings include absence of pulses in the abdominal aorta and in the arteries distally. Distal sites of segmental occlusion produce a further fall in arterial pressure, and ischemic ulceration may appear.
This disorder is often well tolerated for 5 and even 10 years but usually terminates in gangrene of one or both legs. The pathologic findings include atherosclerosis of the arterial wall with superimposed thrombosis. The lumen usually narrows over a period of months and years such that acute symptoms are not likely to occur. Arteriography shows occlusion of the terminal abdominal aorta and often of one or both common iliac arteries. The occlusion may involve any portion of the abdominal aorta from the renal arteries distally. Patients should cease smoking after bypass grafts are performed because the evidence is clear that thrombosis of grafts is appreciably increased by continuance of smoking.
SURGICAL MANAGEMENT
Although thromboendarterectomy with direct reconstitution of flow is appropriate in a few patients, the majority of patients with occlusion of the abdominal aorta are managed by bypass grafts from the aorta to the iliac or more often the common femoral. It may be necessary to perform a thromboendarterectomy distal to the renal arteries to permit a patent lumen for the proximal anastomosis. However, it is important to minimize dissection in this region to prevent damage to the sympathetic and parasympathetic nerves. This helps to prevent postoperative retrograde ejaculation.
Balloon angioplasty can be effective therapy in selected patients.
CUTE ARTERIAL OCCLUSION
Reference to occlusion of the arterial circulation was first made by Harvey in 1628. Labey has been credited with the first successful surgical removal of an arterial embolus in 1911. Heparin—discovered in 1916 and made clinically available in 1936, when used by Best 4—provided surgeons with a means of preventing thrombosis during the repair and manipulation of blood vessels. A review of the surgical literature prior to 1960 indicates that the operative approach to acute arterial occlusion was limited by the lack of a simple and effective method for removing the embolus and distally propagated thrombus. Some of the methods employed included retrograde flushing with saline, suction catheters, vein strippers, and local removal through multiple and lengthy arteriotomies. None of these surgical techniques was particularly effective in reducing the high morbidity (50%) and mortality (50%) associated with acute arterial occlusions. The introduction of the balloon catheter technique in 1963 dramatically simplified the technical aspects of surgical therapy for acute arterial occlusion.
PATHOLOGY
Historically, the primary source of acute arterial occlusion has been embolization from the heart as a result of underlying rheumatic valvular disease. Today, the primary cardiac disorder is atherosclerotic heart disease. Manifestations of this disease include myocardial infarction, atrial fibrillation, congestive heart failure, and ventricular aneurysm. The decline in the prevalence of rheumatic heart disease has led to a decreased incidence of acute occlusion caused by embolization from mitral stenosis. At the same time, advances in cardiac procedures and an overall improvement in medical care have increased life spans, resulting in a significant increase in the incidence of systemic atherosclerosis and thrombotic occlusions of peripheral vessels. In the past 2 decades, occlusion from in situ thrombosis has surpassed occlusion from embolization as the major cause of acute arterial closure.
Regardless of the source or histologic structure of an acute arterial occlusion, it is the location of and secondary events following the occlusion that determine the viability of the afflicted extremity. The majority of surgically treatable occlusions lodge in the lower extremities. Following occlusion, a softer coagulum of blood forms in the areas of decreased flow. In 1941, Linton emphasized that this propagation of thrombus is of major importance in the outcome of the disease process. Distal and proximal propagation of the thrombus also occurs to varying degrees in situations of in situ thrombosis.
Compromised oxygenation of tissue distal to the site of the occlusion leads to an anaerobic cellular metabolism in which tissue becomes acidotic. Elevated concentrations of potassium ions, lactic acid, PCO 2, and the intracellular enzymes (creatine phosphokinase and lysozymes) are released into the bloodstream and interstitial tissue. The ischemic state affects the neural tissue, which induces the symptoms of localized pain and paresthesia. Without proper intervention, these symptoms are followed by muscle swelling and rigor. Tissue necrosis typically occurs after 6 to 12 hours of total ischemia. Further propagation of the distal clot can eventually lead to venous thrombosis.
PREOPERATIVE EVALUATION AND CARE
Arterial emboli most commonly occur in elderly, seriously ill patients with multiple systemic diseases. Prolonged periods of surgical manipulation and general anesthesia have been considered valid deterrents to operative intervention in such patients—particularly when the clinical analysis indicates that conservative measures might preserve life at the cost of limb loss or functional impairment.
The possibility of a successful procedure is obviously dependent on the degree and extent of ischemia at the time of presentation. The condition of the extremity, rather than the duration of the occlusion, represents the primary determinant of operability. Reports in the literature are often confusing because the degree of ischemia has not been documented in assessing the outcome. In a series of 500 patients, every occlusion requiring emergent surgical intervention was characterized by loss of sensation and proprioception in the affected limb. Loss of motor function was present in 20% of the patients, and early rigor in 8%. In the absence of these three signs—loss of sensation and proprioception, loss of motor function, and early rigor—operation for acute occlusion may be considered urgent or even elective. In this same series, successful surgical intervention was possible even after prolonged periods of occlusion. Even in the presence of established gangrene, a successful embolectomy often allows a lower-level amputation.
Patients presenting with an acute arterial occlusion should be assumed to have significant underlying heart disease. The large number of patients presenting with atherosclerotic heart disease reinforces the concept that evaluation of cardiac function should proceed simultaneously with evaluation of the peripheral vasculature. Digitalis, antiarrhythmic agents, morphine, diuretics, and heparin are essential to patient care. However, use of these agents should not delay surgical intervention.
Noninvasive Doppler ultrasound techniques and pressure and waveform measurements are useful in the preoperative setting. They can typically be performed in 5 to 10 minutes, and they provide a useful preoperative benchmark against which to compare postoperative results. In situations of overt advanced ischemia, a physical examination is sufficient. At the time of diagnosis of acute arterial occlusion, 5000 units of intravenous heparin is immediately administered. The presence of congestive heart failure, cardiogenic shock, and significant arrhythmias requires monitoring in the intensive care unit. Placement of a central venous catheter is required in the majority of patients. In addition to allowing rapid administration of drugs and fluids, the catheter permits monitoring of central venous pressures. The pulmonary artery pressure should be monitored in those patients who present with hemodynamic instability or congestive heart failure.
In the presence of an embolus in a lower extremity, the possibility of simultaneous emboli in mesenteric or renal arteries should always be entertained. Hematuria or abdominal complaints indicative of a possible occlusion require preoperative visualization of these vessels. It should be kept in mind that involvement of more than one extremity occurs in approximately 10% of such patients.
INSTRUMENTATION
The balloon embolectomy catheter was constructed with specific adaptations for safe, effective extraction of arterial emboli.
It consists of a hollow, pliable catheter body in graduated sizes for use in major vessels of any caliber. At its proximal end, the syringe fitting provides the means for fluid exchange into a soft elastomeric balloon located at its distal tip. The instrument is inserted as far as possible into the acutely occluded vessel. The balloon is then inflated and withdrawn in the inflated position. By a mechanism of fluid displacement, the balloon maintains uniform, even contact with the vessel wall as it proceeds through areas of narrowing. This mechanism allows removal of thrombotic material distal to stenotic areas. The surgeon manipulates both the syringe and the catheter during withdrawal. In this way, it is easy to judge both the amount of traction required for extraction of the occluding material and the quantity of fluid necessary to effect alternate inflation and deflation as the instrument proceeds through areas of atherosclerotic narrowing or vessels of increasing or decreasing diameter.
The concept of the balloon catheter for embolectomy has remained basically the same since its introduction in 1963. There have been only minor changes in the instrument to increase its effectiveness and reduce the incidence of complications. A variety of balloon configurations and catheter materials have been evaluated. Although balloon catheters with self-adjusting pressure mechanisms and spiked balloon catheters initially appeared to be improvements, their routine use has been associated with significant disadvantages. The utility and effectiveness of the original instrument are tied to its simplicity, and attempts to incorporate nonessential refinements have not proved advantageous or practical. Double-lumen embolectomy catheters are now available, and they have significant utility when used in conjunction with fluoroscopy for selective placement into vessels below a bifurcation point. The thru-lumen catheters can be used for distal irrigation, particularly in situations in which fibrinolytic agents are required as an adjunct to surgical procedures.
The significant increase of acute occlusions from in situ thrombus versus embolic events, combined with the association of such acute thrombotic occlusions with a high incidence of adherent thrombotic material, has produced a need for improved instrumentation for the removal of this more-adherent thrombus. Two new nonballoon catheter systems have been developed to address the problem of adhered thrombus, which is often found at the area of critical narrowing.
The first nonballoon catheter system, called the adherent clot catheter (ACC), was designed specifically for use in native vessels. The second system, called the graft thrombectomy catheter (GTC), was designed for use in synthetic grafts. The technique and use of these instruments are not dissimilar to those for the original balloon embolectomy catheter. These catheters were designed to allow the surgeon to respond to the requirements for removal of the more dense and adherent clot associated with in situ thrombosis.
The initial extraction of thrombus is performed with the standard balloon embolectomy catheter. A critical aspect that is often unappreciated is the information that can be obtained by examining the removed thrombotic material. The removed material should be laid on a towel for visual examination. By viewing this material as a cast of the artery from which it has been removed, one can gain significant insight into both the amount of material remaining and the linear length and location of that material vis-а-vis the arteriotomy. By the simple expedient of noting what is not present, one can safely assume that the residual material still lies within the vessel.
After removal and examination of the softer propagated thrombus, the ACC is introduced in the low-profile configuration. Once past the area of residual material, the catheter is deployed by a button on the proximal end and assumes the shape of a corkscrew. This spiral configuration increases the surface area for traction on the clot without increasing the shear stress on the arterial wall. As with the balloon catheter, the surgeon can influence the diameter of the spiral by manipulating the proximal button. Moving the button back and forth increases or decreases the diameter in response to the force necessary to remove the adherent material.
The GTC is similar in design to the ACC. Essentially, it can be viewed as a variable-diameter ring stripper, for use specifically in synthetic grafts. The body is pliable, and the surgeon can control the diameter of the helix during use. The technique employed is much like that for the ACC. The balloon embolectomy catheter is initially used to remove the propagated thrombus. Again, one can determine the location of the residual densely adherent pannus by examining the removed thrombus. In the setting of aortic bifurcation grafts, the residual material usually lies at the bifurcation or in an area of sharp angulation. Another common area for residual material is the distal anastomotic site of the graft. Therefore, the incision is always made over the junction of the anastomotic site distally, which allows the surgeon to remove the adherent pannus directly or to do an endarterectomy.
After removal of the initial soft clot, an occlusion balloon is employed, followed by the GTC. The occluding balloon catheter is threaded through the helix of the bare wire of the GTC. Proximal occlusion using a balloon avoids the necessity for a proximal major abdominal incision and significantly reduces blood loss during the procedure.
OPERATIVE PROCEDURE
The experience with acute peripheral arterial embolization has clearly indicated that successful management of these patients is related to well-defined factors. From a technical standpoint, it must be recognized that there are varying degrees of difficulty encountered in the attempt to re-establish the peripheral circulation. Patients with advanced ischemia and extensive distal propagation of the thrombus, and those with significant chronic occlusive disease, present the most difficult problems. A careful history and physical examination allow identification of these situations.
Preparation
The procedure is initiated with local anesthesia. An anesthetist should be in attendance to monitor vital signs and to administer a general anesthetic if required or appropriate. The extremity should be surgically prepared from the toes to the nipple line. A bilateral inguinal approach is utilized for aortic emboli, and both extremities are prepared. An iliac embolus also requires bilateral preparation because of the possibility of dislodging a high iliac embolus, with occlusion to the opposite extremity. Although this complication has not occurred in the author's experience, the possibility is always anticipated by preparing the opposite extremity to allow careful monitoring of the pulses. A continuous noninvasive pulse amplitude monitor is useful in the management of these patients. Intraoperative angioscopy also has significant utility and has resulted in a decreased use of arteriography.
Technique
The initial approach to embolic occlusion, regardless of the anatomic location, has been through a common femoral incision. The common femoral artery and deep femoral artery are isolated and occluded with atraumatic vascular clamps. The arterial incision is made in relation to the orifice of the superficial femoral artery and deep femoral artery. A distal exploration is performed initially, and catheters should be routinely placed in the superficial and deep femoral arteries. An open deep femoral circulation is capable of providing the margin necessary to maintain viability in many patients with advanced ischemia or in those who have had a prior chronic occlusion of the superficial femoral system. In the author's experience, instances of recovery of embolic material from the deep femoral artery, even in the presence of a patent common femoral artery, have been frequent. The 2-French and 3-French catheters are most commonly employed for exploration of the deep femoral system, whereas 3-French and 4-French catheters have been found suitable for exploration of the femoropopliteal systems.
The aim of surgical intervention is to restore the peripheral circulation to its preocclusive state. Evaluation of results is based on restoration of pulses, relief of symptoms, and return of normal color and temperature. It is sometimes difficult to assess results when the condition of the extremity of a given patient prior to the acute occlusion is unknown. Conditions such as mental confusion or concurrent illness obviously preclude a total and thorough evaluation. Outcome of therapy is best determined by mortality and amputation rates. The possibility of maintaining a viable, functional extremity following acute arterial occlusion should exceed 90%.
Regardless of the site of the occlusion, failure to recognize and automatically remove any distally propagated thrombus may cause less complete restoration of circulation and possibly amputation. Surgeons have often relied on the presence or absence of backbleeding from the peripheral arterial bed as a guide to distal patency. Repeated clinical observations have confirmed that backbleeding is an unreliable guide to distal patency. Discontinuous thrombotic material is present in approximately one third of cases. Under these circumstances, backbleeding may be quite forceful, despite the presence of total distal obstruction. The presence of adequate collateral vessels causes significant bleeding from the distal segment, despite the fact that the more peripheral arterial bed may be totally occluded. Failure to recognize this circumstance causes less than complete restoration of the circulation. For this reason, routine distal exploration with balloon catheters should be performed independently of the status of the backbleeding.
A physical finding that should be cause for considerable concern after an apparently successful embolectomy is the presence of a water-hammer–type pulse. An apparently stronger than normal pulse has been associated with a high incidence of reocclusion. Under these circumstances, obstruction is present at the small artery and arteriolar level. Re-exploration should include distal irrigation, in conjunction with the use of fibrinolytic agents that are directly introduced into the distal arterial bed at the time of the second procedure.
As previously indicated, clot examination is a critical and expedient means of determining distal patency. A sharp cutoff usually indicates residual material. A divot noted in the cast of the clot is likewise an indication of distal residual material. Smooth tapers with bifurcations are usually an indication of adequate clot removal. If there is uncertainty about the adequacy of distal clot removal, the vessel should be visualized. Angioscopy allows direct access to the femoropopliteal and tibial vessels and minimizes the need for distal incisions and explorations. The proper use of angioscopy quickly documents distal patency and often avoids the need for intraoperative arteriograms.
In the presence of advanced ischemia—that is, in patients with early rigor—the simultaneous presence of major venous occlusion demands consideration. In these patients, the superficial femoral vein is isolated and explored prior to restoration of the arterial circulation. Large venous thrombi are removed by means of venous thrombectomy catheters. Prior to suture closure of the vein, the arterial circulation is re-established. After removal of the arterial occlusions, the distal arterial bed should be adequately irrigated with a heparinized saline solution. The distal venous clamp is then removed to allow smaller thrombi and the acidotic blood to be flushed out. Following completion of this copious heparin flush, the arteriotomy is closed. The vein is flushed once again and, finally, the venotomy is closed. Direct instillation of a fibrinolytic agent through an inflated thru-lumen balloon catheter is recommended in all patients presenting with advanced ischemia.
Immediately following restoration of arterial continuity in extremities with advanced ischemia, significant alterations in electrolytes and acid balance may occur. The venous efflux of ischemic extremities following restoration of arterial continuity was studied in 10 patients. These data clearly indicated that following successful restoration of the circulation, there was a sudden return of acidotic blood with a high potassium content to the heart. This metabolic effect, in conjunction with pooling of blood in the revascularized extremity, can cause significant hypotension. In 8 of the 10 patients studied, adverse effects were associated with clamp release, in the form of significant electrocardiographic changes, hypotension, or both. The necessity of using buffering agents and antiarrhythmic agents should be anticipated at the time of clamp release. Electrolytes should be closely followed in the postoperative period. A high creatine phosphokinase level in the venous efflux indicates significant muscle damage. Both Fisher and co-workers and Haimovici have described the adverse systemic effects that may occur following revascularization of an extremity presenting with advanced ischemia.
ACUTE OCCLUSION IN THE PRESENCE OF SIGNIFICANT OCCLUSIVE DISEASE
A careful history and examination of the uninvolved extremity provide a reliable assessment of the peripheral circulation prior to the acute episode. The patient's general condition and prior level of activity and the extent of pathologic change encountered at the time of operation all have an important role in determining the extent of the surgical procedure. Initially, it is generally advisable to attempt only to return the circulation to its acute preocclusive state. Definitive reconstructive procedures are delayed until a more critical evaluation of the patient is possible. Major reconstructive procedures may be indicated, however, if the general condition is favorable when the patient is first observed. Definitive procedures may be performed at the initial exploration, particularly if there is concern about the viability of the extremity and if the patient was active prior to the acute occlusion. Elderly patients in poor general condition are poor candidates for major reconstructive procedures. Local angioplasty or endarterectomy of the deep femoral system in these situations is simple and quick and can be done under local anesthesia. Frequently, it provides the margin necessary to maintain viability. Local endarterectomy and femorofemoral jump grafts are simple and can also be done under local anesthesia. Adjunctive dilation or atherectomy can easily be employed at the time of either thrombectomy or embolectomy. Adjunctive endovascular procedures are being used with increasing frequency, and they are decreasing the magnitude of the operation in elderly and critically ill patients. In patients of advanced age, durability (although important) should be of secondary consideration.
THROMBOANGIITIS OBLITERANS
(BUERGER'S DISEASE)
In 1908, Leo Buerger published clinical and pathologic observations on young men with severe ischemia of the extremities. These patients were addicted to cigarette smoking and often had migratory superficial phlebitis. Buerger called the syndrome thromboangiitis obliterans because the acute histologic picture was characterized by thrombosis in both arteries and veins and was associated with a marked inflammatory response. However, the condition became more commonly known as Buerger's disease.
CLINICAL MANIFESTATIONS
Thromboangiitis obliterans typically occurs in heavy smokers between 20 and 35 years of age. It was once thought to occur only in men, but several cases have been reported in women. The diagnosis of thromboangiitis obliterans should be considered in any young smoker with peripheral ischemia. Unlike in atherosclerosis, the upper extremities are often involved and there is frequently a history of migratory superficial phlebitis. The ischemic areas are usually sharply demarcated, with relatively good circulation in adjacent tissues. The pain is often excruciating. Associated symptoms include cold sensitivity, Raynaud's phenomenon, and peripheral neuropathy. Foot claudication is particularly characteristic. Exacerbations with smoking and remissions after abstinence from tobacco are typical of thromboangiitis obliterans. The disease has been described in patients who chew tobacco or use snuff as well as in those who smoke. It has also been reported infrequently in nonsmokers. Careful clinical evaluation is necessary to rule out other causes of peripheral ischemia, especially atherosclerosis, hypercoagulable states, and autoimmune vasculitis. Unlike in atherosclerosis, the forearm, calf, or digital arteries are the main sites of occlusion. Absence of a radial pulse, a positive Allen's test indicating ulnar artery occlusion, or superficial phlebitis may be clues to the diagnosis. The iliac, femoral, popliteal, and brachial arteries are usually not involved.
Arteriography early in the disease usually reveals segmental obliteration of small and medium-sized arteries, especially the arteries of the forearm and calf, with a strikingly normal appearance of other vessels. Digital arteries are frequently involved. Atherosclerotic plaques are absent, and collateral circulation in chronic cases is unusually well developed.
The clinical course of thromboangiitis obliterans is protracted and painful but relatively benign. If a patient ceases smoking, prolonged remission usually occurs. However, most patients continue to smoke despite the most emphatic advice. They have repeated attacks and may require multiple distal amputations. Life-endangering complications are uncommon, but infrequently the mesenteric or cerebrovascular circulation may be involved. Long-term life expectancy is only slightly less than that of the general population, unlike patients with comparable degrees of peripheral ischemia due to atherosclerosis. In later life, patients with thromboangiitis obliterans often develop atherosclerosis and may exhibit features of both diseases.
PATHOLOGY
The most characteristic pathologic changes are seen early in the disease process. Thrombosis occurs in arteries and veins of medium to small size, with dense aggregates of polymorphonuclear leukocytes within the thrombus. There is an associated panvasculitis, but the elastic lamina remains intact. 35 Unlike atherosclerosis or periarteritis nodosa, the disease does not cause necrosis of the arterial wall. Later, microabscesses occur, and giant cells appear within the granulation tissue. The thrombus is organized, and recanalization of the lumen may occur. Older lesions show chronic inflammatory infiltrates and/or extensive fibrosis, which often involve peripheral nerves as well as arteries and veins. There is considerable variability in histologic findings, depending on the stage of the disease observed.
ETIOLOGY
A specific cause for thromboangiitis obliterans has never been documented, although the striking association with cigarette smoking suggests a strong etiologic relationship. Patients with thromboangiitis obliterans usually come from lower socioeconomic groups. They often have poor hygiene and a history of chronic fungal infection or cold injury. Fibrinogen levels may be elevated, blood viscosity may be increased, and a hypercoagulable state has been postulated. Hyperaggregability of platelets has also been reported during acute attacks. Familial predisposition has been reported, as well as a greater prevalence of specific leukocyte antigens. An autoimmune etiology of the disease has been postulated, based on the finding of antibodies and lymphocyte-mediated sensitivity to collagen. Antibodies to rickettsial organisms have been reported in patients with thromboangiitis obliterans, as have circulating immune complexes. A genetic factor is suggested by the fact that blacks are rarely affected, whereas the disease is common in Asia. Jewish men were originally reported to be particularly susceptible to the disease, although later studies failed to confirm this predisposition. Autonomic overactivity is suggested by the association with severe peripheral vasospasm and hyperhidrosis and has also been documented through cold pressor tests. Any factor that causes vasospasm, thrombosis, or local inflammation may contribute to the development of thromboangiitis obliterans in a susceptible individual. It is likely that some immunologic process activated by smoking plays the primary etiologic role in thromboangiitis obliterans.
INCIDENCE
Based on data from World War II veterans, DeBakey and Cohen estimated the incidence of thromboangiitis obliterans at seven or eight cases per 100,000 white males 20 to 44 years of age. However, the incidence of thromboangiitis obliterans has decreased markedly since World War II. At the Mayo Clinic, its prevalence declined 10-fold from 1947 to 1976, although there has been a slight upward trend in recent years. The diagnosis of thromboangiitis obliterans was made in 24% of all young adults (age 35 or younger) presenting to the Mayo Clinic with lower limb ischemia from 1953 to 1981.
In a retrospective review of 100 patients with ischemic finger ulcerations, thromboangiitis obliterans was the final diagnosis in 9%.
In patients with severe ischemia and digital gangrene, the incidence was 13%. In another study of 700 patients with small-vessel arterial disease, thromboangiitis obliterans was the final diagnosis in 3.7%. 23 At present, thromboangiitis obliterans comprises less than 1% of all patients with severe peripheral ischemia in the United States. In Israel and Eastern Europe, the corresponding incidence is approximately 5%, whereas in Japan it is 16%. Patients with thromboangiitis obliterans are observed much more frequently in Asia, even in populations where atherosclerosis is rare.
MANAGEMENT
The major problem in treating patients with thromboangiitis obliterans is the management of pain, which is often excruciating. Narcotics are usually necessary but must be used cautiously because of the frequency of drug addiction. Peripheral or sympathetic nerve blocks may provide temporary pain relief, especially when the disease is accompanied by severe vasospasm. When nerve blocks prove beneficial, dorsal or lumbar sympathectomy may provide more lasting benefit, although experience is anecdotal. Meticulous conservative treatment of ischemic lesions may result in healing, especially in the upper extremity, but relief of pain sometimes requires amputation.
Every effort should be made to have the patient stop smoking, since remission often follows abstinence from cigarettes. No specific medication has found wide acceptance. Anticoagulants, dextran, phenylbutazone, inositol niacinate, and corticosteroids have all been recommended. More recently, prostaglandin therapy and defibrotide 33 have been advocated, as well as agents to prevent platelet aggregation. Pentoxifylline has also been advocated. Severe hand ischemia due to acute thrombosis in thromboangiitis obliterans has been dramatically improved by intra-arterial infusion of urokinase, followed by small-vessel balloon catheter angioplasty and anticoagulation.
Arterial reconstruction is usually impossible because of the distal nature of the disease, but it should be considered in segmental proximal occlusions. A successful mesenteric artery bypass has been reported in a 23-year-old man with visceral thromboangiitis obliterans. Arterial reconstructions for thromboangiitis obliterans have a higher failure rate than comparable reconstructions for atherosclerosis. Microvascular transplantation of free omental grafts to areas not amenable to arterial reconstruction has been successfully employed, as have pedicled omental grafts. When gangrene occurs, amputation at the lowest possible level is indicated. Digital amputations for thromboangiitis obliterans have a better healing rate than digital amputations for atherosclerotic gangrene.