Aim: It was recently suggested that a 6 mmHg difference exists in both chest and foot transcutaneous oxygen pressure (TcPo2) between diabetic and non-diabetic volunteers apparently free from vascular disease. If a difference can also be found in diabetic and non-diabetic patients with clinically suspected critical limb ischemia (CLI), this may question the use of the same 30 mmHg threshold proposed by the "TASC" in the definition of CLI. We analyse whether a difference can be found for chest and foot TcPo2 respectively between diabetic and non-diabetic patients referred for clinically suspected CLI.
Methods: A retrospective matched paired study was performed among 60 diabetic and 60 non-diabetic subjects with peripheral artery disease and suspected critical limb ischemia. Results are presented as median [25-75 centiles].
Results: Groups were comparable in terms of gender, age, height, systolic blood pressure and treatments (except for renin-angiotensin inhibitors). Chest-TcPo2 was 53 [43-57] mmHg in diabetic and 60[49-65] mmHg in non-diabetic patients (P<0.01). Foot-TcPo2 was 12[3-34] mmHg in diabetic and 15[3-36] mmHg in non-diabetic patients (Non significant). A multi-parametric step by step regression analysis showed that chest-TcPo2 was inversely associated with weight, then with diabetes and gender.
Conclusions: TcPo2 is lower at the chest but not at the foot level in diabetic than in non-diabetic patients with suspected CLI. Then, the "30 mmHg threshold" proposed in the definition of lower-limb CLI is likely applicable in both diabetic and non-diabetic patients.