Chest
Volume 112, Issue 3, September 1997, Pages 722-728
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Clinical Investigations: Pulmonary Vasculature
Noninvasive Diagnosis of Suspected Severe Pulmonary Embolism: Transesophageal Echocardiography vs Spiral CT

https://doi.org/10.1378/chest.112.3.722Get rights and content

Objective

Patients with pulmonary embolism (PE) and echocardiographic signs of right ventricular overload have worse prognosis and may require aggressive therapy. Unequivocal confirmation of PE is required before thrombolysis or embolectomy. This study compares the value of transesophageal echocardiography (TEE) and spiral CT (sCT) in direct visualization of pulmonary artery thromboemboli in patients with suspected PE and echocardiographic signs of right ventricular overload.

Material and methods

Forty-nine consecutive patients (29 men and 20 women), aged 52.2±18.3 years, with clinical suspicion of acute (23) or chronic (26) PE and otherwise unexplained right ventricular overload at transthoracic echocardiography underwent TEE and sCT. Main and lobar (central) pulmonary arteries were searched for emboli with both TEE and sCT, while segmental and subsegmental (distal) pulmonary arteries were searched only with sCT.

Results

Of 40 patients with PE confirmed by high-probability lung scan (27) or angiography (13), central pulmonary arterial emboli were found at TEE and sCT in 32 (80%) and 36 (90%) patients, respectively. Neither method reported false central PE (specificity, 100%). When distal pulmonary arteries were analyzed, sensitivity of sCT increased to 97.5%, but three patients with primary pulmonary hypertension according to standard tests were misclassified as having distal PE (specificity, 90.1%). Most patients had bilateral PE according to sCT (34/36) and standard tests (40/40) but not TEE (15/32), probably due to its topographic limitations.

Conclusions

Because of high prevalence of bilateral central pulmonary thromboemboli in patients with hemodynamically significant PE, both sCT and TEE allow its definitive confirmation in most cases. Thrombi reported by sCT distally to lobar arteries should be interpreted with caution.

Section snippets

Materials and Methods

In the period from November 1994 to May 1996, 211 patients with clinical suspicion of acute or chronic PE were referred to our echocardiographic laboratory for standard transthoracic echocardiography (TTE). This group was formed by consecutive patients seen by the staff of our department for suspected PE in this period, with the exception of a few moribund patients with disseminated neoplasmatic disease who were not considered candidates for further diagnostic management. Patients with signs of

Results

TEE reported the presence of at least one pulmonary arterial thromboembolus in 32 of 49 investigated patients. Emboli were revealed in 17 of 23 patients with suspected acute PE and in 15 of 26 patients with suspected chronic PE (Table 1 and Figs 1 and 2). Emboli were found bilaterally in 15 cases; in 9 of them the clinical picture indicated acute PE. Unilateral right-sided, intrapulmonary thromboemboli were reported in 12 subjects, and the left-sided thromboemboli were reported in five others.

Discussion

Diagnostic strategies for PE are being modified because of the successful introduction of venous ultrasound to the clinical practice.16, 17 Another breakthrough in the management of PE may be expected with more frequent application of imaging techniques permitting direct visualization of thromboemboli in the pulmonary arteries. This study is focused on the relative value of two such methods in the diagnosis of suspected PE in patients with signs of the right ventricular pressure overload

Conclusions

Due to the high prevalence of bilateral central pulmonary arterial thrombi in patients with hemodynamically significant PE, the diagnosis may be reliably confirmed in most cases with TEE despite its topographic limitations.

sCT has an excellent diagnostic power for centrally located thrombi. However, when sCT detects thrombi limited to the segmental or subsegmental pulmonary arteries, the diagnosis of PE should be made with caution.

When compared with sCT, the limitations of TEE are not

Acknowledgments

We would like to thank Mrs. K. Borek for her excellent technical assistance during TEE examinations.

References (23)

  • WoodardPK et al.

    Detection of pulmonary embolism: comparison of contrast-enhanced spiral CT and time-of-flight MR techniques

    J Thorac Imaging

    (1995)
  • Cited by (0)

    The echocardiographic part of this study was supported by grant KBN 4P05B06610.

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