UCLA

Aims

The association of subclinical atherosclerotic disease in the coronary arteries and thoracic aorta with incident peripheral arterial disease (PAD) is unknown. We investigated the association between coronary artery calcium score (CACs) and thoracic aortic calcium score (TACs) with incident clinical and subclinical PAD.

Methods and results

The Multi-Ethnic Study of Atherosclerosis (MESA) recruited 6814 men and women aged 45-84 from four ethnic groups who were free of clinical cardiovascular disease at enrolment. Coronary artery calcium score and thoracic aortic calcium score were measured from computed tomography scans. Participants with a baseline ankle-brachial index (ABI) ≤0.90 or >1.4 were excluded. Abnormal ABI was defined as ABI ≤0.9 or >1.4 at follow-up exam. Multivariable logistic regression and Cox proportional hazards models were used to test the associations between baseline CACs and TACs with incident abnormal ABI and clinical PAD, respectively. A total of 6409 participants (female: 52.8%) with a mean age of 61 years were analysed. Over a median follow-up of 16.7 years, 91 participants developed clinical PAD. In multivariable analysis, each unit increase in log (CACS + 1) and log (TACs + 1) were associated with 23% and 13% (P < 0.01for both) higher risk of incident clinical PAD, respectively. In 5725 (female: 52.6%) participants with an available follow-up ABI over median 9.2 years, each 1-unit increase in log (CACs + 1) and log (TACs + 1) were independently associated with 1.15-fold and 1.07-fold (P < 0.01for both) higher odds of incident abnormal ABI, respectively.

Conclusion

Higher baseline CACs and TACs predict abnormal ABI and clinical PAD independent of traditional cardiovascular risk factors and baseline ABI.