Background: Although measuring blood pressure at the bilateral brachia is common in medical practice, its clinical significance in patients with suspected coronary artery disease (CAD) has not been fully clarified.
Methods: To define the significance of inter-arm systolic blood pressure difference in patients with suspected CAD, and to assess the relationship between inter-arm pressure difference and CAD, simultaneous brachial and ankle blood pressure measurements and stress myocardial single-photon emission computed tomography (SPECT) were performed in 386 consecutive patients with suspected CAD, excluding those with previous myocardial infarction or coronary revascularization.
Results: Subclavian artery stenosis, defined as > or = 15 mmHg inter-arm systolic blood pressure difference, was found in 27 patients (7%). Age (65 +/- 12 vs 65 +/- 11 years), male sex (21/27 vs 244/359), prevalence of hypertension(63% vs 56%), hypercholesterolemia (63% vs 62%), diabetes mellitus(33% vs 38%), cigarette smoking (44% vs 41%) and family history of CAD (15% vs 12%) were similar between patients with subclavian artery stenosis and those without. The incidence of decreased ankle-brachial pressure index (ABI) was higher (37% vs 12%, p = 0.001), and percentage ischemic myocardium as assessed by SPECT was greater (9.0 +/- 8.5% vs 5.6 +/- 6.6%, p < 0.05) in patients with subclavian artery stenosis than in those without. Furthermore, significant correlations were observed between inter-arm pressure difference and percentage ischemic myocardium (r = 0.13; p = 0.01), and ABI (r = -0.26, p < 0.0001). Among 386 patients, 283 underwent coronary angiography, and 63% of those who had inter-arm blood pressure difference had CAD. Furthermore, 83% of those CAD patients had multi-vessel CAD, which is regarded as a high-risk subset for subsequent cardiac events.
Conclusions: Inter-arm pressure difference is often found in patients with suspected CAD, and is associated with significant CAD and peripheral artery disease. Thus, inter-arm pressure difference may be regarded as a simple marker for coronary and peripheral artery diseases.