Clinical study
Likelihood of left main coronary artery compression based on pulmonary trunk diameter in patients with pulmonary hypertension

https://doi.org/10.1016/j.amjmed.2003.11.015Get rights and content

Abstract

Purpose

In patients with pulmonary hypertension, extrinsic compression of the left main coronary artery by a dilated pulmonary trunk may cause angina, left ventricular ischemia, and sudden death. We assessed coronary artery compression in relation to pulmonary trunk diameter and other demographic, echocardiographic, hemodynamic, and scintigraphic variables.

Methods

Thirty-six patients (aged 15 to 86 years) with pulmonary hypertension, either idiopathic or associated with congenital heart disease, were enrolled. Left main coronary artery compression was defined angiographically as ≥50% obstruction associated with downward displacement of the vessel. Pulmonary trunk and aortic diameters were measured by transthoracic echocardiography.

Results

Twenty-six patients had angina, of whom 7 had left coronary artery compression. Compression was related to pulmonary trunk diameter (P = 0.002) and to the ratio of pulmonary trunk diameter to aortic diameter (P = 0.02). Compression was not seen at pulmonary artery diameters <40 mm; among 19 patients with values ≥40 mm, the rate was 37%. Similarly, compression did not occur at pulmonary trunk to aortic diameter ratios <1.21; among 27 patients with ratios ≥1.21, the rate was 26%.

Conclusion

In pulmonary hypertension, noninvasive measurement of pulmonary trunk diameter may be helpful in determining the likelihood of left coronary artery compression and in selecting patients for diagnostic coronary angiography.

Section snippets

Patients

All patients with pulmonary hypertension treated at the Heart Institute of the University of São Paulo in 2002 were eligible for the study. The entry criteria were a mean pulmonary artery pressure >25 mm Hg and a pulmonary wedge pressure <15 mm Hg. All subjects were initially evaluated as outpatients. The study protocol was approved by the Scientific Committee of the Heart Institute, and informed consent was obtained from all patients or their parents (in the case of adolescents).

Clinical assessment

Information on

Results

Thirty-six patients (26 women [72%]) were enrolled in the study (Table 1). The mean (± SD) age was 49 ± 18 years (median, 47 years; range, 15 to 86 years). Patients had a mean pulmonary artery pressure of 49 ± 14 mm Hg (median, 49 mm Hg; range, 30 to 90 mm Hg), a mean pulmonary trunk diameter of 41 ± 12 mm (median, 40 mm; range, 25 to 73 mm), and a mean pulmonary trunk to aortic diameter ratio of 1.56 ± 0.50 (median, 1.39; range, 1.0 to 2.83).

At presentation, 13 patients were in New York Heart

Discussion

This study shows that, in patients with pulmonary arterial hypertension, left coronary artery compression may cause angina and left ventricular ischemia more frequently than previously recognized. Compression was found in 19% of patients and was closely related to the diameter of the pulmonary trunk but not to pulmonary artery pressure or chest pain.

The clinical and angiographic presentation defined two distinct groups. The first consisted of 10 patients without a history of chest pain. All

Acknowledgements

We thank Mrs. Roseli Polo for technical assistance in the preparation of this manuscript.

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