Elsevier

Journal of Nuclear Cardiology

Volume 12, Issue 3, May–June 2005, Pages 318-323
Journal of Nuclear Cardiology

Original article
Myocardial perfusion SPECT imaging in patients with myocardial bridging

Presented in part at the 6th International Conference of Nuclear Cardiology, Florence, Italy, April 27–30, 2003.
https://doi.org/10.1016/j.nuclcard.2005.01.009Get rights and content

Background

Although myocardial perfusion single photon emission computed tomography (SPECT) imaging is widely used to assess myocardial ischemia in patients with known or suspected coronary artery disease, only a few patients with myocardial bridging have been evaluated with nuclear techniques. Furthermore, it has been suggested that dipyridamole stress images might underestimate perfusion defects compared with exercise stress images. This study was done to determine the concordance of exercise stress SPECT images with that obtained by dipyridamole stress SPECT images as a means of detecting ischemia in patients with myocardial bridging.

Methods and Results

Sixteen consecutive patients with angina and normal arteries but myocardial bridging of the left anterior descending artery underwent rest-exercise stress SPECT imaging. Within 2 weeks after angiograms were obtained, only dipyridamole stress images were repeated. The mean angiographic systolic occlusion within the myocardial bridges was 73% ± 10%. Overall, the prevalence of an abnormal scan was no different in patients who underwent exercise stress myocardial perfusion imaging (MPI) as compared with patients who underwent dipyridamole stress MPI (14/16 [88%] vs 13/16 [81%], respectively; P = .953). Exercise stress MPI showed a higher stress score than dipyridamole stress MPI, but the difference did not reach statistical significance (7.5 ± 3.3 vs 6 ± 2.7, P = .147). The strength of agreement among exercise stress MPI and dipyridamole stress MPI studies was good (κ = 0.765; 95% CI, 0.318 to 1.211; P < .05).

Conclusions

Cardiac SPECT studies can be used effectively for assessing ischemia in patients with angina and myocardial bridging. The evaluation of myocardial perfusion with dipyridamole stress SPECT imaging showed a good agreement with exercise stress SPECT imaging for the detection of ischemia in this group of patients.

Section snippets

Study Population

We included 16 consecutive patients from 2000 to 2003 with typical symptoms of angina and normal arteries as documented by coronary angiography but myocardial bridging of the midportion of the left anterior descending artery (LAD) with more than 50% narrowing during systole. All patients had had at least one previous hospital admission because of exertional chest pain with significant ST-segment depression of greater than 0.1 mV or T-wave inversion in the anterior leads. No patients had

Patient Characteristics

The clinical characteristics of the patients are listed in Table 1. Patients were predominantly men, with a high prevalence of hypertension (69%). The mean angiographic systolic occlusion (mSO) within the myocardial bridges was 73% ± 9.7% (median systolic occlusion, 75%, range, 51% to 82%). Most of the patients had left ventricular hypertrophy (LVH), and patients with a median systolic occlusion higher than 75% had a higher mean septal thickness than patients with a median systolic occlusion

Discussion

In this study, in which all of the patients had typical angina and normal arteries but myocardial bridging of the midportion of the LAD, myocardial ischemia was induced with exercise stress MPI in 88% of patients and with dipyridamole stress MPI in 81% of patients. In contrast, previous studies demonstrated perfusion abnormalities in only 33% to 65% of patients with myocardial bridging in whom MPI was performed.11, 16, 17 Significant technical and clinical differences may explain the

Acknowledgment

We thank the technologists of the nuclear cardiology department for their technical assistance. We also gratefully acknowledge Patricia Vallejo for her careful review of the manuscript.

The authors have indicated they have no financial conflicts of interest.

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