Clinical significance of inter-arm pressure difference and ankle-brachial pressure index in patients with suspected coronary artery disease.

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.