The diagnosis and treatment of acute pulmonary embolism

Abstract

Background: Pulmonary embolism (PE) is a cardiovascular emergency with high morbidity and mortality.

Methods: Review of relevant literature retrieved by a selective Medline search, including current guidelines.

Results: Hemodynamically unstable patients are considered to have high-risk PE, whereas hemodynamically stable patients are considered to have non-high-risk PE. After classification into one of these two risk groups, patients undergo further diagnostic evaluation for PE according to the appropriate risk-adapted algorithm. Patients who are in cardiogenic shock or have persistent arterial hypotension (high-risk PE) should undergo multidetector computed tomography (MDCT) or echocardiography at once, so that a PE, if present, can be treated immediately by thrombolysis. For hemodynamically stable patients with non-high-risk PE the proper diagnostic strategy is determined by the clinical probability of PE, which can be calculated with the aid of validated scoring systems and is based on both MDCT and D-dimer levels. For further risk stratification in hemodynamically stable patients, tests are performed to detect right ventricular dysfunction or myocardial injury, either of which indicates intermediate-risk PE. In addition to specific therapy, patients with high-risk PE, patients at high risk for hemorrhage and these with severe renal insufficiency should be anticoagulated with unfractionated heparin. All other patients should be treated with low-molecular-weight heparin or fondaparinux. Thereafter, long-term oral anticoagulation with vitamin K antagonists is recommended.

Conclusion: Modern algorithms have considerably simplified the diagnosis and treatment of acute PE. It would be desirable for these algorithms to be rapidly implemented in routine practice, because speedy diagnosis and immediate treatment can lower the morbidity and mortality associated with PE.

Figure 1

^*1, systolic blood pressure <90 mmHg or a drop of >40 mmHg for more than 15 minutes that was not triggered by new onset arrhythmia, hypovolemia or sepsis; ^*2, risk of early PE related mortality (in-hospital or 30-day mortality); (modified from Walther A, Schellhaaß A, Böttiger BW, Konstantinides S: Diagnosis, therapy and secondary prophylaxis of acute pulmonary embolism. Anaesthesist 2009; 58: 1048–54. With kind permission of Springer Science and Business Media).

Figure 2

MDCT, multidetector computed tomography with imaging of the pulmonary arteries; RV, right ventricular; CT, computed tomography; ^*1, For high-grade unstable patients a treatment decision can be made using indirect echocardiographic signs of PE alone (LV dilatation, RV hypokinesis, RV pressure overload, paradoxical septal motion, free-floating thrombi); (modified from Walther A, Schellhaaß A, Böttiger BW, Konstantinides S: Diagnosis, therapy and secondary prophylaxis of acute pulmonary embolism. Anaesthesist 2009; 58: 1048–54. With kind permission of Springer Science and Business Media).

Figure 3

MDCT, multidetector computed tomography with imaging of the pulmonary arteries; ^*1, For negative MDCT despite high clinical probability, further diagnostic clarification using compression ultrasonography or ventilation-perfusion scintigraphy to increase diagnostic certainty may be sensible—particularly before a final decision against anticoagulation is made. However, prospective management studies indicate that a negative MDCT finding obviates the need for anticoagulation (15, 16). With low or intermediate clinical probability, the MDCT is only considered positive if more than one subsegmental thrombus or at least one proximal thrombus can be detected. If single detector CT is performed instead of MDCT, due to the low sensitivity compression ultrasonography of the lower extremities should also be performed if there is a negative finding in order to be able to exclude PE with sufficient certainty; (modified from Walther A, Schellhaaß A, Böttiger BW, Konstantinides S: Diagnosis, therapy and secondary prophylaxis of acute pulmonary embolism. Anaesthesist 2009; 58: 1048–54. With kind permission of Springer Science and Business Media)