Prognostic value of ankle-brachial index and dobutamine stress echocardiography for cardiovascular morbidity and all-cause mortality in patients with peripheral arterial disease
Results of this study were presented at Sixteenth European Chapter Congress of the International Union of Angiology, EUROCHAP 2005, Glasgow, United Kingdom, Oct 25-27, 2005.
Received 25 October 2006; accepted 11 March 2007. published online 22 June 2007.
Background
Peripheral arterial disease (PAD) is associated with an excessive risk for cardiovascular events and mortality. To determine measures prognostic of adverse events, ankle-brachial index (ABI) was compared with dobutamine stress echocardiography (DSE) in patients referred to our vascular center for the evaluation of PAD.
Methods
The medical records of consecutive patients referred for the concurrent evaluation of PAD and coronary artery disease (CAD) between 1992 and 1995 were reviewed for subsequent cardiovascular events and death.
Results
Among 395 patients (mean age, 69.7 ± 9.6 years; 40% women), 341 had abnormal ABI and 268 had abnormal DSE (95 fixed and 173 stress-induced wall motion abnormalities). During a mean follow-up of 4.7 years, 27.3% of patients experienced a cardiovascular event, and 39.4% died. By multivariate analysis, ABI provided the strongest prediction of all-cause mortality (hazard ratio [HR], 2.34; 95% confidence interval [CI], 1.36 to 4.05; P = .002). Conversely, DSE with inducible or fixed wall motion abnormalities showed no association with cardiovascular events or increased mortality in multivariate analysis. The only DSE variable independently predictive of mortality was decreased left ventricular ejection fraction (<50%) at peak stress (HR, 1.70; 95% CI, 1.22 to 2.36; P = .002). Statin and aspirin therapy, but not β-blockers, were protective. There was no relation between ABI and wall motion index score at rest or after stress.
Conclusions
In high-risk patients referred to our vascular center for the evaluation of PAD, the assessment of ABI provided a strong independent prediction of all-cause mortality. Therefore, proper interpretation of this simple, affordable, and reproducible measure extends beyond the assessment of PAD severity. Although a poor left ventricular response to dobutamine was also predictive, other echo variables were not.
aDivision of Cardiovascular Diseases, Mayo Clinic, Rochester, Minn
bDivision of Biostatistics, Mayo Clinic, Rochester, Minn.
Reprint requests: Waldemar E. Wysokinski, MD, Division of Cardiovascular Medicine, Mayo Clinic and Foundation for Education and Research, 200 First St SW, Rochester, MN 55905.
Competition of interest: none.
Statistical support was provided by discretionary funding from the Cardiovascular Division at Mayo Clinic.
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