Name
ARTERIAL EMBOLUS & THROMBOSIS
DESCRIPTION
DETAIL
CAUSES . Emboli . Cardiac: - Atrial flutter/fi brillation - Valve disease - Myocardial infarction - Cardiomyopathy - Cardiac tumors - Endocarditis . Aneurysms - cardiac, aortic, peripheral . Paradoxical . Thrombosis: . Atherosclerotic occlusive disease . Aortic and peripheral aneurysms - especially popliteal . Hypercoagulable states . Venous gangrene . Drug abuse . Heparin allergy . Vascular bypass . Trauma: . Blunt . Penetrating . Vascular and cardiac interventional procedures -------------------------------------------------------------------------- DIFFERENTIAL DIAGNOSIS Emboli vs thrombosis . Emboli : . Myocardial diseases - myocardial infarction, arrhythmias - atrial fibrillation . Aneurysms . Pain as first symptom . Thrombosis : . Absence of heart disease - Arrhythmias/infarction . Chronic vascular history . Bilateral changes of chronic ischemia . Numbness rather than pain as fi rst symptom . Vascular procedures - bypass/interventional . Acute aortic dissection; chest or back pain . Acute deep vein thrombosis; massive swelling and warm skin . Low fl ow statesβ’ Acute diagnosis is by history and exam: Laboratory data is for preoperative evaluation, elucidation of etiology, or documentation of severity of ischemia. * Noninvasive - indirect: . Doppler: presence or absence of flow . A/ai (ankle/arm index) = dorsal pedal/posterior tibial pressure MULTIPLIED by brachial pressure ; a/ai > 0.30 favorable * Arteriography . Rarely indicated preoperatively in threatened limb . May help differentiate thrombosis from embolus in non-threatened limb
TYPENOTES
BASIC TREATMENT: Based on detailed exam, history, and Doppler exam. Triage determines appropriate therapy. * VIABLE: . Mild ischemic pain . Normal neurologic exam . Capillary refi ll present . Arterial signals present by Doppler in distal extremity . A/ai > 0.30 * THREATENED: . Ischemic pain . Mild neurologic deficit - Weakness of dorsiflexion - Minimal sensory loss - light touch and/or vibratory . No pulsatile fl ow by Doppler . Venous flow present * MAJOR ISCHAEMIC CHANGES: - irreversible . Profound sensory loss . Muscle paralysis . Absent capillary refill . Skin marbling . Muscle rigor . No arterial or venous signals by Doppler GENERAL MEASURES . Time is of the essence . In the threatened category nothing should delay appropriate therapy . Unless contraindicated, systemic heparinization to decrease clot propagation and prophylaxis against further emboli . Resuscitation and stabilization of patient to extent permitted by time * Viable - symptomatic - Heparin - Arteriography - Embolism - Surgical removal if acceptable operative risk, e.g., balloon embolectomy - Anticoagulation vs intraarterial thrombolytics if prohibitive risk * Thrombosis - Trial of thrombolytics and correction of arterial defect if good risk - Anticoagulation if poor risk or thrombolytics contraindicated * Threatened - salvageable . Heparin (see Medications) . Minimal delay to defi nitive therapy . Arteriography . Individualized thrombolysis and/or operative procedure (depending on extent of thrombosis and amenability for surgical removal) . Thrombolysis to optimize alternatives . Adjunctive operative therapy - Intraoperative lytic therapy - Bypass - Patch angioplasty * Major ischemia - irreversible . Arteriography usually not warranted . Attempts at reperfusion contraindicated . Anticoagulation . Definitive amputation if possible Arterial embolus & thrombosis DRUG(S) OF CHOICE * Heparin . 100 units/kg IV loading dose (approximately 5,000-10,000 units) . Continuous heparin infusion suffi cient to double the PTT, generally 1000 to 1500 units/hour * TPA/Urokinase PREVENTION/AVOIDANCE . Chronic anticoagulation in atrial arrhythmia . Reduction of risk factors for atherosclerosis POSSIBLE COMPLICATIONS . Acidosis . Myoglobinuria . Hyperkalemia . Recurrent occlusion . Failure to remove clot/obstruction . Compartment syndromes/reperfusion syndrome; delayed or instant . Predisposing factors include: combined arterial injury, profound and prolonged ischemia, hypotension . Occurs both in upper and lower extremities . Clinical findings : - Severe pain - Pain with passive muscle movement - Hypesthesias of nerves in compartment - Paralysis of nerves especially peroneal - foot drop - Tender, tense edema - Compartment pressure > 30-45 mm Hg . Consequences of unrecognized compartment syndrome - acute - Amputation - Sepsis - Myoglobin renal failure - Shock - Multiple organ failure . Delayed - Ischemic contracture - Infection - Causalgia - Gangrene . Treatment - Fasciotomy EXPECTED COURSE/PROGNOSIS . 90% good outcome with prompt treatment . Delayed/untreated associated with high mortality and limb loss . 20-30% hospital mortality associated with causative factors
RELATED DISEASE
Not Available Disease
DISEASE
INVESTIGATION
COMPLETE BLOOD COUNT, ECHOCARDIOGRAPHY, COLOR DOPPLER