Purpose The anterolateral thigh (ALT) flap has gained popularity over the last few decades for the reconstruction of various surgical defects given its distinct advantages including great versatility and low donor site morbidity. The anatomy of the main perforating vessel of the ALT flap, the descending branch of the lateral circumflex femoral artery (dbLCFA), has been well described in the literature, however only one study has investigated its patency in patients with significant co-morbidities. The aim of this study is to assess the degree of vascular stenosis of the dbLCFA in patients with multiple co-morbidities as compared to medically-fit controls. Material and methods 128 sets of angiographic data were collected from 93 patients retrospectively over a 12 month period. The percentage stenosis of superficial femoral artery (SFA), LCFA and dbLCFA was measured and converted into an established scoring system. Statistical analyses were performed using Chi-square tests. Results Mean stenosis of dbLCFA was 12.5%. Interestingly, 24.0% of patients without peripheral vascular disease (PVD) showed some degree of stenotic changes in dbLCFA, whereas only 10.7% of those with PVD had some degree of stenosis. There was no correlation between dbLCFA stenosis and patient co-morbidity. The SFA was significantly affected by smoking, hypercholesterolaemia (p Conclusions This study shows that the dbLCFA is not affected by patient co-morbidity including peripheral vascular disease when compared to medically-fit controls. Even in individuals with severe vascular stenosis of the superficial system (including complete obstruction); there is often complete sparing of the deep vascular system. Surgical reconstruction using the ALT flap is a relatively safe procedure for patients even with multiple co-morbidities including significant peripheral vascular disease and no additional pre-operative investigations are required.