The lifetime risk of amputation in patients with diabetes is 15-fold higher than that of the non-diabetic population. Once patients develop end-stage peripheral vascular disease (PVD), the treatment options for diabetic foot ulcers become limited and amputation is commonly the result. Developing new methods to detect and treat early-stage PVD in patients with diabetes remains our best hope for limiting diabetes-related amputation. Current non-invasive studies do not sensitively identify early-stage vascular disease or serve to track its progression. Based on work done by investigators studying coronary calcification, we seek to answer the following question: Is there a similar relationship between the amount of calcification found in tibial arteries and the severity of PVD in patients with type II diabetes? If this is the case, then tibial calcification could be used as a surrogate marker for the severity of athero-occlusive diseases and for the identification of high risk patients. We will test the hypothesis that tibial artery calcification scores derived by multi-slice CT are related to the clinical severity of vascular disease in a diabetic patient population. We will first (specific aim 1) explore the relationship between tibial artery calcification and clinical category of PVD in patients with type II diabetes, and then (specific aim 2) examine the correlation between the tibial artery calcification score and the amount of angiographically-determined tibial artery occlusive disease in these patients. We will recruit three groups of patients with type II diabetes: Group 1- no clinical evidence of PVD, Group 2 -- clinical evidence of PVD but no pedal ischemia, and Group 3 -clincial evidence of PVD and pedal ischemia. We will also recruit an age and gender matched control group to more fully understand the specific effect of type II diabetes on tibial calcification.
For Aim 1, mean TAC scores in each of these groups will be compared using a case-contol design and ANOVA statistical methods.
For Aim 2, patients will undergo evaluation of their vascular anatomy by CT angiography and we will calculate a correlation coefficient (r) and predictive value (P). Results from this preliminary inquiry would support larger case-control studies, cohort studies, and randomized trials to test the utility of using TAC scoring in the care of patients with type II diabetes. Our ultimate goal is to prevent the marco-vascular complications of diabetes, and to decrease the incidence of lower extremity amputation that causes disability in our patients.
