Anticoagulant treatment for subsegmental pulmonary embolism

Background

Acute pulmonary embolism (PE) is a common cause of death, accounting for 50,000 to 200,000 deaths annually. It is the third most common cause of mortality among the cardiovascular diseases, after coronary artery disease and stroke. The advent of multi-detector computed tomographic pulmonary angiography (CTPA) has allowed better assessment of PE regarding visualisation of the peripheral pulmonary arteries, increasing its rate of diagnosis. More cases of peripheral PEs, such as isolated subsegmental PE (SSPE) and incidental PE, have thereby been identified. These two conditions are usually found in patients with few or no classic symptoms such as coughing (including coughing up blood), chest or upper back pain, acute shortness of breath, or general or specific failure of the circulation that is either cardiac or peripheral in nature. However, in patients with an impaired cardiac and pulmonary condition the classic PE symptoms can be found with isolated SSPEs. Incidental SSPE is found casually in asymptomatic patients, usually by diagnostic imaging performed for other reasons (for example routine computed tomography (CT) for cancer staging in oncologic patients). Patients with isolated SSPE or incidental PE may have a more benign clinical presentation compared with those with proximal PEs. However, the clinical significance and prognosis in these patients has to be studied to evaluate whether anticoagulation therapy is required.

Review question

What are the effectiveness and safety of anticoagulation therapy versus no intervention in patients with subsegmental pulmonary embolism (SSPE) or incidental SSPE?

Study characteristics

No studies met the inclusion criteria of the review.

Key results

There is no randomised controlled trial evidence (current until December 2015) for the effectiveness and safety of anticoagulation therapy versus no intervention in patients with isolated subsegmental pulmonary embolism (SSPE) or incidental SSPE and, therefore, we can not draw any conclusions. Well-conducted research is required before informed practice decisions can be made.

Quality of evidence

It is not possible to review methodological quality in the absence of studies eligible for inclusion in the review.

Authors' conclusions: 

There is no randomised controlled trial evidence for the effectiveness and safety of anticoagulation therapy versus no intervention in patients with isolated subsegmental pulmonary embolism (SSPE) or incidental SSPE, and therefore we can not draw any conclusions. Well-conducted research is required before informed practice decisions can be made.

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Background: 

Acute pulmonary embolism (PE) is a common cause of death, accounting for 50,000 to 200,000 deaths annually. It is the third most common cause of mortality among the cardiovascular diseases, after coronary artery disease and stroke.

The advent of multi-detector computed tomographic pulmonary angiography (CTPA) has allowed better assessment of PE regarding visualisation of the peripheral pulmonary arteries, increasing its rate of diagnosis. More cases of peripheral PEs, such as isolated subsegmental PE (SSPE) and incidental PE, have thereby been identified. These two conditions are usually found in patients with few or none of the classic PE symptoms such as haemoptysis or pleuritic pain, acute dyspnoea or circulatory collapse. However, in patients with reduced cardio-pulmonary (C/P) reserve the classic PE symptoms can be found with isolated SSPEs. Incidental SSPE is found casually in asymptomatic patients, usually by diagnostic imaging performed for other reasons (for example routine CT for cancer staging in oncologic patients).

Traditionally, all PEs are anticoagulated in a similar manner independent of the location, number and size of the thrombi. It has been suggested that many patients with SSPE may be treated without benefit, increasing adverse events by possible unnecessary use of anticoagulants.

Patients with isolated SSPE or incidental PE may have a more benign clinical presentation compared with those with proximal PEs. However, the clinical significance in patients and their prognosis have to be studied to evaluate whether anticoagulation therapy is required.

This review is an update of a Cochrane systematic review first published in 2014.

Objectives: 

To assess the effectiveness and safety of anticoagulation therapy versus no intervention in patients with isolated subsegmental pulmonary embolism (SSPE) or incidental SSPE.

Search strategy: 

The Cochrane Vascular Trials Search Co-ordinator searched the Specialised Register (last searched December 2015) and CENTRAL (2015, Issue 11). MEDLINE, EMBASE, LILACS and clinical trials databases were also searched.

Selection criteria: 

Randomised controlled trials of anticoagulation therapy versus no intervention in patients with SSPE or incidental SSPE.

Data collection and analysis: 

Two review authors inspected all citations to ensure reliable selection. We planned for two review authors to independently extract data and to assess the methodological quality of identified trials using the criteria recommended in the Cochrane Handbook for Systematic Reviews of Interventions.

Main results: 

No studies were identified that met the inclusion criteria.

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