2013 Treatment of Acute Pulmonary Embolism

8/13/2019 2013 Treatment of Acute Pulmonary Embolism

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TREATMENT OF ACUTE PULMONARY EMBOLISM

INTRODUCTION

Acute pulmonary embolism (PE) is common and often fatal, with a mortality rate of

approximately 30 percent without treatment. Most deaths are due to recurrent PE within the

first few hours of the initial event. Therapy with anticoagulants decreases the mortality rate

to 3 to 8 percent, making it imperative that effective therapy be instituted as quickly as

possible.

The clinical severity of acute PE can be highly variable, ranging from asymptomatic to severe

hypoxemia, right ventricular failure, shock, and death. As a result, therapy varies from patient

to patient and requires considerable clinical judgment. Common questions asked by clinicians

when a patient presents with PE include:

Which anticoagulant should I administer? How much? How long? Should I administer thrombolytic therapy? Should an inferior vena caval filter be placed? Is embolectomy indicated? Can the patient be treated as an outpatient?

Treatment of patients with acute PE is reviewed here. More detailed discussions regarding

anticoagulation and thrombolysis in acute PE are presented separately. The epidemiology,

prognosis, pathophysiology, risk factors, symptoms, signs, and diagnosis of acute PE are

discussed separately.

RESUSCITATION

When a patient presents with suspected acute PE, the initial focus is on stabilizing the patient.

This may require respiratory support, hemodynamic support, and/or empiric anticoagulation.

Respiratory support

Supplemental oxygen should be administered if hypoxemia exists. Severe hypoxemia or

respiratory failure should prompt consideration of intubation and mechanical ventilation. Of

note, patients with coexistent RV failure are prone to hypotension following intubation. The

initiation of mechanical ventilation is discussed separately.


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Hemodynamic support

Hemodynamic support should be instituted when a patient presents with acute PE and

hypotension. Hypotension may be roughly defined as a systolic blood pressure


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clinical suspicion of acute PE, a moderate clinical suspicion for acute PE and the diagnostic

evaluation is expected to take longer than four hours, or a low clinical suspicion for acute PE

and the diagnostic evaluation is expected to take longer than 24 hours [9]. Stratification of

clinical suspicion and the initiation of empiric anticoagulant therapy for suspected acute PE

are discussed separately.

Once it has been determined that empiric anticoagulant therapy is indicated, it should be

initiated as soon as possible because its efficacy may be related to achieving therapeutic levels

of anticoagulation within the initial 24 hours. A pooled analysis of three anticoagulation trials

demonstrated that the risk of recurrent PE was 25 percent if the activated partial

thromboplastin time (aPTT) was not therapeutic within the first 24 hours after initiation of

heparin.

In contrast to the approach for patients with no excess risk for bleeding, empiric anticoagulanttherapy should be considered on a case-by-case basis if there is a moderate or high risk of

bleeding, or if there are conditions in the differential diagnosis that are contraindications to

anticoagulation (eg, pericardial tamponade, aortic dissection). If anticoagulant therapy is

judged to be contraindicated, the diagnostic evaluation must be expedited so that therapies

that do not require anticoagulation (eg, inferior vena caval filter, embolectomy) can be

initiated if acute PE is confirmed. Stratification of the risk of bleeding as low, moderate, or

high is described separately.

POST-RESUSCITATION

The diagnostic evaluation should be performed as quickly as possible once the patient has

been stabilized.

For patients in whom the diagnostic evaluation EXCLUDES an acute PE, anticoagulant therapy

should be discontinued if it was initiated empirically during the resuscitative period.

Alternative causes of the patients symptoms and signs should be sought.

For patients in whom the diagnostic evaluation CONFIRMS an acute PE:

Anticoagulant therapy should be initiated or continued if it was begun empirically.Placement of an inferior vena caval filter is an appropriate alternative to anticoagulant

therapy for patients who have failed anticoagulant therapy, developed complications

of anticoagulation, or have an unacceptable bleeding risk.

It should be determined whether the clinical presentation is severe enough to warrantthrombolysis. Embolectomy is appropriate for patients whose presentation is severe

enough to warrant thrombolysis, but in whom thrombolysis is either contraindicated

or unsuccessful.

This approach is depicted in an algorithm for the management of suspected acute PE.
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Anticoagulant therapy

Anticoagulant therapy is considered primary therapy for acute PE. It is discussed in detail

separately, including indications for empiric therapy, assessment of the risk for bleeding,

anticoagulant agents, dosing, monitoring, outcomes, and duration of therapy.

Thrombolytic therapy

Thrombolytic therapy is generally considered for patients with severe clinical manifestations.

Thrombolytic therapy for acute PE is reviewed in detail separately, including the indications,

contraindications, agents, administration, and outcomes.

IVC filters

Inferior vena caval (IVC) filters provide a screen in the inferior vena cava, allowing blood to

pass through while large emboli from the pelvis or lower extremities are blocked or

fragmented before reaching the lung. Placement of an IVC filter is generally considered in

patients who have contraindications to anticoagulation, failed anticoagulation, or developed

a complication due to anticoagulation. In addition, IVC filter placement is often considered

when the hemodynamic or respiratory compromise is severe enough that another PE may be

lethal. IVC filter indications, types, outcomes, and complications are reviewed separately.

Embolectomy

Embolectomy (ie, removal of the emboli) can be performed using catheters or surgically. It

should be considered when a patient's presentation is severe enough to warrant thrombolysis

(eg, persistent hypotension due to acute PE), but thrombolytic therapy either fails or is

contraindicated. Whether surgical or catheter embolectomy is chosen depends upon the

availability of resources and expertise of the institution, since a direct comparison has never

been performed and data regarding the effectiveness of each therapy are limited.

Catheter embolectomy Rheolytic embolectomy, rotational embolectomy, suctionembolectomy, thrombus fragmentation, and ultrasound plus low-dose thrombolytic

therapy are techniques that have been utilized to reduce the embolic burden in patients

with acute PE. Case series using these techniques are small and none of the techniques

has been compared with other forms of therapy in randomized trials. Larger studies are

needed to determine which, if any, catheter technique is most effective compared to

alternative treatment modalities.

Rheolytic embolectomy Using a rheolytic embolectomy catheter (ie, the AngioJetembolectomy system), embolectomy is accomplished by injecting pressurized saline

through the catheter's distal tip, which macerates the emboli. The saline and

fragments of clot are then sucked back into an exhaust lumen of the catheter fordisposal. The major disadvantage of this system is that a large venous sheath or a


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surgical embolectomy had fewer recurrent PE. In addition, there were fewer deaths and

fewer major bleeding complications among the surgical embolectomy group, although

these differences did not achieve statistical significance. Surgical embolectomy has not

been compared to catheter embolectomy or primary thrombolytic therapy.

Transesophageal echocardiography (TEE) should be performed before or during

pulmonary embolectomy to look for extrapulmonary thrombi (ie, thrombi in the right

atrium, right ventricle, or vena cava). In a series of 50 patients with PE, intraoperative TEE

detected extrapulmonary thrombi in 13 patients (26 percent), which altered the surgical

management of five patients (10 percent).

Cardiac arrest predicts mortality during surgical embolectomy. In one study of 36 patients

with profound hypotension due to acute PE (but without cardiac arrest) who underwent

surgical embolectomy, 35 patients survived (97 percent). In contrast, operative mortalityamong patients with acute PE who were resuscitated from a cardiac arrest, then

underwent surgical embolectomy was approximately 75 percent. Mortality after cardiac

arrest due to acute PE is high in the nonsurgical setting as well.

INPATIENT OR OUTPATIENT THERAPY

Not all patients who have symptomatic acute PE need to be admitted to the hospital for initial

therapy. Patients who do not require supplemental oxygen and have a normal pulse, normal

blood pressure, and no recent history of bleeding, may reasonably be considered for

outpatient management if they do not have serious comorbid conditions (eg, ischemic heart

disease, liver or renal failure, thrombocytopenia). Additional considerations include the

amount of support from family and friends, access to a telephone, and the ability to return to

the hospital quickly if there is clinical deterioration.

This is supported by several observational studies and a randomized trial that showed no

significant differences in outcomes when patients treated as outpatients were compared with

patients treated as inpatients. In the trial, 344 patients with symptomatic acute PE and a low

risk of death were randomly assigned to receive either inpatient or outpatient therapy with

low molecular weight heparin followed by oral anticoagulation. Within 90 days, recurrentvenous thromboembolism occurred in one outpatient (0.6 percent) and no inpatients, death

occurred in one outpatient and one inpatient, and major bleeding occurred in three

outpatients (1.8 percent) and no inpatients. The mean length of stay was 0.5 days for

outpatients and 3.9 days for inpatients. The trial defined a low risk of death as falling within

pulmonary embolism severity index (PESI) class I or II. The PESI is described separately. In

stable patients being considered for outpatient therapy or early discharge, it is logical that an

important risk factor for poor outcome would be residual clot burden in the legs. In fact, in

patients with a first episode of acute symptomaticPE, the presence of concomitant deep vein

thrombosis (DVT) has been shown to be an independent predictor

of death in the ensuingthree months after diagnosis. Thus, when outpatient therapy of acute PE is considered, the


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clinician may wish to evaluate the legs prior to discharge (ie, assessment of the thrombotic

burden may assist with risk stratificationof these patients).

INFORMATION FOR PATIENTS

UpToDate offers two types of patient education materials, The Basics and Beyond the

Basics. The Basics patient education pieces are written in plain language, at the 5 th to 6th

grade reading level, and they answer the four or five key questions a patient might have about

a given condition. These articles are best for patients who want a general overview and who

prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer,

more sophisticated, and more detailed. These articles are written at the 10 thto 12thgrade

reading level and are best for patients who want in-depth information and are comfortable

with some medical jargon.

Here are the patient education articles that are relevant to this topic. We encourage you to

print or e-mail these topics to your patients. (You can also locate patient education articles

on a variety of subjects by searching on patient info and the keyword(s) of interest.)

Basics topics Beyond the Basics topics

1. When a patient presents with suspected acute pulmonary embolism (PE), initial careshould focus on stabilizing the patient. Patients with significant hypoxemia or

hemodynamic compromise should be admitted to the intensive care unit.

2. Supplemental oxygen should be administered if hypoxemia exists. Severe hypoxemia orrespiratory failure should prompt intubation and mechanical ventilation.

3. If the patient presents with systemic hypotension, prompt hemodynamic support shouldbe instituted. Intravenous fluid administration may be beneficial; however, clinicians

should be wary of administering more than 500 to 1000 mL during the initial resuscitation

period.

4. For patients whose hypotension does not resolve with intravenous fluids, we recommendprompt vasopressor therapy (Grade 1B). We suggest using norepinephrine as the initial

agent (Grade 2C). Dopamine, epinephrine, or a combination of dobutamine plus

norepinephrine may also be effective.

5. The decision about whether or not to initiate empiric anticoagulant therapy duringresuscitation and the diagnostic evaluation depends upon both the degree of clinicalsuspicion for acute PE and the risk for bleeding.


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6. When the diagnostic evaluation EXCLUDES acute PE, anticoagulant therapy isdiscontinued if it was initiated empirically during the resuscitative period and alternative

causes of the patients symptoms and signs are sought.

7. When the diagnostic evaluation CONFIRMS acute PE, anticoagulant therapy is initiated (orcontinued if it was begun empirically) and it is determined whether the clinicalpresentation is severe enough to warrant thrombolysis. Anticoagulant and thrombolytic

therapy for acute PE are reviewed separately.

8. An inferior vena cava filter is an appropriate alternative for patients with confirmed acutePE who have a high risk for bleeding, complications of anticoagulation, recurrent PE

despite therapeutic anticoagulation, or hemodynamic or respiratory compromise that is

severe enough that another PE may be lethal.

9. For patients with acute PE in whom thrombolysis is indicated, but who fail thrombolysisor have contraindications to thrombolysis, we suggest catheter or surgical embolectomy

if the necessary resources and expertise are available (grade 2C). The decision of whetherto pursue one of these approaches should be based upon local expertise.

10.Outpatient management is reasonable for selected patients with acute PE who do notrequire supplemental oxygen and have a normal pulse, normal blood pressure, and no

recent history of bleeding, assuming that they do not have serious comorbid conditions

(eg, ischemic heart disease, liver or renal failure, thrombocytopenia). Additional

considerations include the amount of support from family and friends, access to a

telephone, and the ability to return to the hospital quickly if there is clinical deterioration.

Documents

2013 Treatment of Acute Pulmonary Embolism