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Massive PE Matt White November 3, 2009

Objectives PE Basics Massive PE Medical treatment Lytics Embolectomy IVC Filters Follow-up

Virchow’s triad Thrombosis: triggered by venostasis, hypercoagulability, and vessel wall inflammation. All clinical risk factors for DVT/PE have their basis in one or more elements of the triad.

PE Incidence In the United States, incidence is 1 per ,000 new cases annually in US

Is that enough? autopsy studies show that equal number of patients are diagnosed with PE at autopsy vs. diagnosis by clinicians Easy diagnosis to miss

Massive PE occlusion of the pulmonary artery that exceeds 50% of its cross-sectional area, resulting in progressive hemodynamic compromise Usually defined as presenting with systolic blood pressure < 90 mmHg. In two large international studies, this accounted for % of all PE patients.

Clinical course obstruction of the PA to this degree initiates a cascade of physiologic events, which if not interrupted early, ultimately results in cardiac arrest and death in up to 70% of patients in the first hour Not solely dependent on size of clot, rather on clot and functional capability of the patient's cardiovascular system.

Medical treatment of massive PE Supplemental oxygen High dose IV heparin Hemodynamic support – IV fluids (empiric 500 mL) increased right ventricular (RV) wall stress can decrease the ratio of RV oxygen supply to demand. (ischemia, deterioration of RV function, and worse RV failure) –Vasopressors (no evidence for which one) Norepinephrine, epinephrine, or dopamine usually first line Thrombolytics (if no contraindications)

Thrombolytics No clinical trial with conclusive mortality benefit. –Meta analysis of 8 RCTs (n=679); heparin & lytics vs heparin, no difference in mortality (OR 0.89 [ ]), major hemorrhage (OR 1.61 [ ]), or minor hemorrhage (OR 1.98 [ ]) Transient improvement in hemodynamics –Improved RV function (after 12hrs, gone by 7 days) –Lower PA pressures

ICOPER (International Cooperative Pulmonary Embolism Registry) 108 patients with massive PE Thrombolysis was performed in 33 patients, surgical embolectomy in 3, and catheter embolectomy in 1 Thrombolytic therapy did not reduce 90-day mortality (46.3%; [ %] vs. 55.1% [ %]. Hazard Ratio of Recurrent PE rates at 90 days similar in patients with and without thrombolytic therapy (12% for both).

Indications for thrombolytics Persistent hypotension due to PE (ie, massive PE) is most widely accepted indication Other considerations –severe hypoxemia –large perfusion defects –right ventricular dysfunction –free-floating right atrial or ventricular embolus –patent foramen ovale Thrombolysis should be considered only after PE has been confirmed (in most cases)

Risks of thrombolytics Increased risk of major hemorrhage (19% of patients) –intracranial hemorrhage (5%) –retroperitoneal hemorrhage (15%) –GI bleed (30%) –Unknown site of bleeding (45%) Menstruation not a contraindication Allergic reactions –More with streptokinase (0.5%, mild reaction in 10%) From retrospective analysis of 104 patients

Administering thrombolytics Bolus infusion may be effective more quickly without increase risk of bleeding No evidence that intrapulmonary arterial infusion of greater benefit than peripheral venous infusion

Pearls of thrombolytics Avoid unnecessary invasive procedures (especially arterial punctures) Discontinue anticoagulant therapy (usually) No evidence for superiority between different thrombolytic agents

Embolectomy considered when patient's presentation is severe enough to warrant thrombolysis (e.g., persistent hypotension), but thrombolysis either fails or is contraindicated.

Catheter embolectomy Rheolytic: injecting pressurized saline through the catheter's distal tip, which macerates the emboli –large venous sheath or a venous cut-down is required to insert the large catheter, which increases the risk of bleeding at the insertion site

Catheter embolectomy Rotational: rotational catheter fragmentation –uses conventional catheters

Surgical embolectomy

first successful surgical pulmonary embolectomy was performed by Kirschner in 1924 Initially performed blindly as a closed cardiac procedure Now performed on cardiopulmonary bypass with clots extracted from the opened PAs under direct visualization

Surgical embolectomy Indication Main: systemic hypotension due to PE in a patient in whom thrombolysis is contraindicated –Possible: echocardiographic evidence of an embolus trapped within a patent foramen ovale, the right atrium, or the right ventricle Limited to large medical centers because an experienced surgeon and cardiopulmonary bypass are required

Procedural logistics Transesophageal echocardiography (TEE) to look for extrapulmonary thrombi (ie, RA, RV or vena cava). In series of 50 patients with PE, TEE detected extrapulmonary thrombi in 13 patients (26%), which altered the surgical management of five patients (10%)

Mortality of surgical embolectomy Estimates of mortality vary widely from % Mortality after cardiac arrest due to PE is extremely high in the nonsurgical setting as well.

Indicators of Mortality

IVC Filter Indications Absolute contraindication to anticoagulation (e.g., active bleeding) Recurrent PE despite adequate anticoagulant therapy Complication of anticoagulation (e.g., severe bleeding) Hemodynamic or respiratory compromise that is severe enough that another PE may be lethal

Algorithm (from surgeons) Large thrombus in pulmonary artery + hemodynamic instability requiring vasopressor support and evidence of impending right ventricular failure = open embolectomy. Mild hemodynamic instability (without evidence of severe RV strain) = thrombolytic therapy ( if no contraindications) –Serial echocardiograms should be performed to evaluate for improvement. –If thrombolytic therapy is contraindicated and catheter thrombectomy is readily available, then consideration for this technique is appropriate. –If patient has large proximal thrombus and is hemodynamically stable but cannot receive thrombolytics or catheter thrombectomy, open embolectomy is then indicated.

References Kucher N, Rossi E, De Rosa M, Goldhaber SZ. Massive pulmonary embolism. Circulation 2006;113: Dauphine C, Omari B. Pulmonary Embolectomy for Acute Massive Pulmonary Embolism. The Annals of Thoracic Surgery. 2005; 79(4) Up to Date