Isolated pulmonary embolism may predict risk of long-term arterial thrombosis

Key points to remember:

• The diagnosis of isolated pulmonary embolism may indicate the presence of CVD and a long-term risk of arterial thrombosis.
• Isolated pulmonary embolism “should be recognized as a distinct clinical entity”.

Evidence from a systematic review suggests that adults with isolated pulmonary embolismthe majority of whom are women, are more likely to have prevalent cardiovascular disease and are at increased risk of arterial thrombosis.

“Isolated PE appears to be associated with a different clinical profile and risks that PE associated with deep vein thrombosis“, Philipp S. Wild, MD, MSc, from the Academic Medical Center at Johannes Gutenberg University in Mainz, Germany, and colleagues wrote. “It is unclear whether isolated PE should be considered a separate clinical entity that potentially requires alternative therapy.”

Wild and colleagues performed a systematic review and meta-analysis of 50 studies involving 435,768 patients with PE, comparing PE phenotypes and pooling data on risk factors, clinical characteristics, and clinical parameters . Systematic DNA analysis was performed in 13 studies.

The findings were published in eClinicalMedicine.

Among studies at low risk of bias, 30% of patients had isolated PE. Most patients with isolated PE (57%) were female. Factor V Leiden (OR=0.47; 95% CI, 0.37-0.58) and prothrombin G20210A mutations (OR=0.55; 95% CI, 0.41-0.75 ) were less common in patients with isolated PE.

Compared to patients with PE associated with DVT, patients with isolated PE were more likely to be female (OR=1.3; 95% CI, 1.17-1.45), have had recent invasive surgery (OR = 1.31; 95% CI, 1.23-1.41), have a history of MI (OR = 2.07; 95% CI, 1.85-2 .32), have left CI (OR = 1.7; 95% CI, 1.37-2.1), peripheral arterial disease (OR = 1.36; 95% CI, 1.31-1 .42) and diabetes (OR = 1.23; 95% CI, 1.21-1.25).

In a summary of clinical outcome data, the risk of recurrent venous thromboembolism in isolated PE was half that of patients with PE associated with DVT (RR = 0.55; 95% CI, 0. 44-0.69), although a single study accounted for 65% of the pooled estimate, according to the researchers. The risk of arterial thrombosis was almost three times higher in patients with isolated PE than in those with PE associated with DVT, with an RR of 2.93 (95% CI, 1.43-6, 02).

“Regardless of the origin of the thrombus, the results of this study suggest that isolated PE should be recognized as a distinct clinical entity, and a diagnosis of isolated PE should be considered as a tentative biomarker for an increased risk of arterial thrombosis,” the researchers wrote. “Although the outcome data is still very limited, there is ample cross-sectional data to suggest that patients diagnosed with isolated PE, even in the face of potential misclassification, are at increased risk for cardiovascular disease. Conversely, the risk of VTE recurrence appears to be much lower for patients with isolated PE.”

The researchers noted that randomized controlled trials are needed to determine whether alternative treatment regimens may benefit this common patient subgroup.