Lower Extremity Arterial Calcification as a Predictor of Coronary Atherosclerosis in Patients with Peripheral Arterial Disease

Abstract

Background: Until now, there has been no study on the relationship between the calcification of the lower extremity arteries and significant coronary arterial disease (CAD).

Objectives: To evaluate whether lower extremity calcium scores (LECS) are associated with CAD and whether this can predict multivessel-CAD in patients with peripheral arterial disease (PAD).

Patients and methods: We retrospectively enrolled 103 PAD patients without cardiac symptoms or known CAD. All patients underwent cardiac computed tomography (CT) and lower extremity CT within 1 month and were categorized as nonsignificant CAD, single-CAD, or multivessel-CAD. The coronary calcium scores (CCS) were quantitatively measured according to the Agatston method and LECS were semi-quantitatively measured according to the presence of lower extremity calcification in the segment. The extent of CAD was evaluated according to the presence of ≥ 50% luminal diameter stenosis in the segment of CAD.

Results: LECS in multivessel-CAD were significantly higher than those in nonsignificant CAD (10.0 ± 5.8 versus 4.0 ± 3.1, P < 0.001). LECS significantly correlated with CCS (r = 0.831, P < 0.001) and the extent of CAD (r = 0.631, P < 0.001). Multivariate regression analysis demonstrated LECS and log-transformed CCS were independent predictors for multivessel-CAD. In receiver operating characteristic curve analysis, the diagnostic performance of LECS was 0.807 (95% confidence interval = 0.724-0.891, P < 0.001) for predicting multivessel-CAD.

Conclusion: Peripheral arterial calcification is significantly correlated with CAD extent in patients with PAD. Peripheral arterial calcification can be a useful marker for predicting multivessel-CAD.

Keywords: Atherosclerosis; Coronary Artery Disease; Multidetector Computed Tomography; Peripheral Arterial Disease; Vascular Calcification.

Figure 1.. A 74 year-old male patient with claudication underwent lower extremity CT angiography. Lower extremity calcium was detected in the distal aorta, both common iliac arteries, both external iliac arteries, both common femoral arteries, both proximal superficial femoral arteries, right distal superficial femoral arteries, and right popliteal artery. A, The lower extremity calcium score was 11. B, Coronary CT angiography CCTA was performed and the coronary calcium score was 315.52. C, Invasive coronary angiography showed chronic total occlusion of the left anterior descending artery (arrowhead) and severe stenosis of the proximal left circumflex artery (arrow). D, Severe stenosis in trifurcation site of distal RCA (arrow). The stenotic lesions observed by invasive angiography were matched with CCTA results.

Figure 2.. Receiver operator characteristic curves of log-transformed coronary calcium score (log CCS), lower extremity arterial index (LEAI), and lower extremity calcium score (LECS) in all segments, showing the diagnostic performance for the prediction of multivessel-coronary artery disease. The area under the curve of LECS in all segments, that of LEAI, and that of CCS were 0.820 (95% confidence interval = 0.734 to 0.907; P < 0.001), 0.661 (95% CI = 0.551 to 0.771; P = 0.009) and 0.865 (95% confidence interval = 0.792 to 0.938; P < 0.001), respectively.