Comparison of colour duplex ultrasound and ankle-brachial pressure index measurements in peripheral vascular disease in type 2 diabetic patients with foot infections.
OBJECTIVE
Peripheral vascular disease (PVD) is a common cause of morbidity and mortality and is reported to be more common among diabetic subjects compared to non-diabetic subjects. The aim of the study was to compare the specificity and sensitivity of ankle-brachial index (ABI) measured by peripheral doppler with the colour duplex ultrasound (CDU) for diagnosis of PVD.


METHODS
One hundred type 2 diabetic patients admitted to our diabetic centre with foot lesions underwent both colour duplex ultrasound and ankle-brachial index measurements. PVD was diagnosed if the individual had haemodynamically significant obstruction on CDU, or if the ABI was < 0.9. The sensitivity and specificity of ABI was determined using the CDU as 'gold standard'.


RESULTS
The mean age of the study group was 59.5 +/- 10.1 years and the mean duration of diabetes was 11.7 +/- 8.1 years. Of the total 100 subjects, six subjects had calcification of peripheral vessels and they were not included while calculating for sensitivity and specificity of ABI. Twenty (21.3%) subjects diagnosed as PVD by the CDU were not classified as PVD by the ABI measurements. Conversely, only three subjects (3.2%) classified as PVD by ABI had normal arteries based on CDU scanning. Overall, ABI had low sensitivity (70.6%) but a high specificity (88.5%). The overall agreement between CDU and ABI was poor (k = 0.20).


CONCLUSIONS
ABI is a good initial screening tool but some patients with significant stenosis in lower extremities would be missed, if ABI measurement alone is used for diagnosis of PVD.
Premalatha
G
G
Madras Diabetes Research Foundation and MV Diabetes Specialities Centre (P) Ltd., Gopalapuram, Chennai, India.
Ravikumar
R
R
Sanjay
R
R
Deepa
R
R
Mohan
V
V
D000368:Aged; D000842:Ankle; D015331:Cohort Studies; D003924:Diabetes Mellitus, Type 2 / Q000150:complications* / Q000175:diagnosis; D017719:Diabetic Foot / Q000175:diagnosis* / Q000209:etiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016491:Peripheral Vascular Diseases / Q000175:diagnosis* / Q000209:etiology; D011312:Pressure; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D018615:Ultrasonography, Doppler, Color / Q000379:methods*