Chest
Volume 137, Issue 1, January 2010, Pages 164-170
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Original Research
Venous Thromboembolism
Impending Paradoxical Embolism: Systematic Review of Prognostic Factors and Treatment

https://doi.org/10.1378/chest.09-0961Get rights and content

Background

Little is known about the optimal management of impending paradoxical embolism (IPDE), a biatrial thromboembolus caught in transit across a patent foramen ovale. Our aim was to review observational studies on this subject to identify prognostic factors and to compare mortality and systemic embolism between treatments.

Methods

Systematic literature searches in Medline, Embase, and Cochrane Library identified 154 studies (174 patients). The primary end point was 30-day mortality. The secondary end point was systemic embolism during treatment.

Results

Thirty-day mortality was 18.4%. On univariate analysis, age (64±13.9 vs 56.7±16.5; P = .01), coma (12.9% vs 2.2%; P = .02), and systemic embolism (71.9% vs 51.4%; P = .048) at presentation were significantly increased among nonsurvivors. Surgical thromboembolectomy had lower mortality than other treatment groups (10.6%; P = .04). In multivariable models, no prognostic factor was a significant independent predictor of mortality. Surgically treated patients had nonsignificantly reduced mortality (odds ratio [OR], 0.65 [0.24–1.72]; P = .65) and thrombolysis-treated patients had increased mortality (OR, 1.62 [0.43–5.97]; P = .47). However, systemic embolism during treatment and combined mortality and systemic embolism was decreased in the surgery group (OR, 0.13 [0.03–0.67]; P = .02 and OR, 0.26 [0.11–0.60]; P = .001).

Conclusions

This review attempts to help guide what to do in IPDE, despite severe limitations of the methods. Surgical thromboembolectomy showed a nonsignificant trend toward improved survival, significantly reduced systemic embolism, and composite of mortality and systemic embolism, compared with anticoagulation alone. Thrombolysis, on the other hand, had the opposite effect, although not significantly.

Section snippets

Literature Search

Two investigators (P.O.M. and A.P.) independently did systematic electronic and manual literature searches using a predetermined to identify reports of IPDE. Articles were identified in electronic database searches of Medline, Embase, and the Cochrane Library, from 1964 to 2008. To achieve the maximum sensitivity of the search strategy and identify all reports on the subject, we used appropriate free text and thesaurus terms including “paradoxical embolism,” “impending paradoxical embolism,”

Literature Search Results and Baseline Characteristics

Literature search results are shown in Figure 1. One hundred fifty-four studies (see online supplement) and one personal communication were included in the review, representing 174 patients clinically diagnosed with IPDE. The IPDE passed through a patent foramen ovale in all but one patient, in whom the thrombus passed through an atrial septal defect. Most patients were reported as isolated case reports, with a ratio of 1.13 patients per study. The clustering effect was thus assumed to be

Discussion

Despite the high prevalence of patent foramen ovale, estimated at 26%,14 paradoxical embolism is a rare event. It requires the following criteria for diagnosis: (1) presence of deep venous thrombosis or pulmonary embolism; (2) abnormal communication between the right and left circulation; (3) clinical, angiographic, or pathologic evidence of systemic embolism; and (4) presence of a favorable pressure gradient promoting right-to-left shunting.10, 15 IPDEs represent DVTs embolized to the heart

Conclusions

This review attempts to help guide what to do in IPDE, despite the limitations of the methods. Surgical thromboembolectomy showed a nonsignificant trend toward improved survival and significantly reduced systemic embolism and composite of mortality and systemic embolism, compared with anticoagulation alone. Thrombolysis, on the other hand, had the opposite effect, although not to a significant level.

Acknowledgments

Author contributions: Dr Myers: contributed to designing the study, performing literature searches, collecting and analyzing the data, and drafting the manuscript.

Dr Bounameaux: contributed to designing the study, critically reviewing the manuscript, and approving the final draft.

Dr Panos: contributed to designing the study, performing literature searches, critically reviewing the manuscript, and approving the final draft.

Dr Lerch: contributed to designing the study, critically reviewing the

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