The anatomical sequence of arterial calcification in peripheral vascular disease and its implications for free flap reconstruction

Introduction

Lower extremity (LE) free tissue transfer (FTT) in patients with peripheral vascular disease (PVD) is complicated by arterial calcification, which may occur in free flap pedicle vessels as well as recipient vessels. However, no studies have examined the likelihood of encountering calcification in common flap pedicles or the anatomical sequence in which this process occurs.

Methods

Computed tomography (CT) and x-ray (XR) imaging were obtained in PVD patients undergoing LE FTT. Using software designed for cardiac vessel calcium analysis, calcium volume was quantified in flap pedicles of the trunk, upper extremity, pelvis, and lower extremity on CT images. Descriptive statistics were used to identify flap vessels most affected by calcification. A novel scoring system (Qual Calc) was developed to predict the likelihood of flap pedicle calcification by examining the qualitative presence of vascular calcification on plain foot XR.

Results

Trunk pedicles (subscapular) showed statistically significantly lower calcification rates and volumes than lower extremity pedicles. LE flap pedicles were most likely to be calcified, with the lateral femoral circumflex artery being the most frequently calcified. Qual Calc score was highly predictive of quantified calcium volume in workhorse flaps of the upper and lower extremity.

Conclusion

Arterial calcification proceeds anatomically from the lower extremity cephalad towards the chest. Flaps based on the subscapular system are least affected by calcification and represent a safer reconstructive choice than thigh-based flaps for limb salvage in vasculopathic patients. Simple foot x-rays can be used to predict flap pedicle calcification with a reasonable degree of accuracy.