A dynamic objective evaluation of peripheral arterial disease by near-infrared spectroscopy.
OBJECTIVE
Near-Infrared Spectroscopy (NIRS), suitable for dynamic measurements, is not routinely used for peripheral arterial disease (PAD). We propose a dynamic NIRS-based measurement to quantify variations in muscle metabolism in PAD.


METHODS
Sixty-seven consecutive PAD patients (males=56, age 71.6+/-8.7 years) and 28 healthy subjects (males=12, age 30.4+/-11.9 years) were studied. An echo-colour Doppler (ECD) was performed and the ankle-brachial index (ABI) was calculated. Participants performed an incremental treadmill test with NIRS probes on the gastrocnemius. Variations in oxygenated (HbO(2)), deoxygenated (HHb), total (tHb=HbO(2)+HHb), and differential (dHb=HbO(2)-HHb) haemoglobin were recorded and quantified as area-under-curve (AUC) within the range 1.7-3.0 km h(-1). Heart rate was recorded, and the number of beats in the same interval was calculated (dHr).


RESULTS
O(2)Hb(AUC), HHb(AUC) and dHb(AUC) differed between diseased and non-diseased legs (P<0.0001) and exhibited different patterns related to PAD severity according to the ABI value. A compensatory heart rate increase was observed in PAD patients. Compared with the ECD positivity for occlusions/stenoses or multiple plaques, only the receiver-operating characteristic (ROC) analysis of dHb(AUC) (area=0.932, P<0.0001) showed a sensitivity/specificity of 87.6/93.4 for values <or=-197 (LR+LR-: 13.36/0.13).


CONCLUSIONS
The dynamic NIRS-based test, quantifying muscle metabolic response according to presence and degree of PAD, allows the evaluation of patients with walking disabilities.
Manfredini
F
F
Vascular Diseases Center, University of Ferrara, Ferrara, Italy. mdf@unife.it
Malagoni
A M
AM
Felisatti
M
M
Mandini
S
S
Mascoli
F
F
Manfredini
R
R
Basaglia
N
N
Zamboni
P
P
D000368:Aged; D000369:Aged, 80 and over; D000842:Ankle / Q000098:blood supply; D015415:Biomarkers / Q000097:blood; D001794:Blood Pressure; D001916:Brachial Artery / Q000503:physiopathology; D016022:Case-Control Studies; D005080:Exercise Test; D005260:Female; D006339:Heart Rate; D006454:Hemoglobins / Q000378:metabolism*; D006801:Humans; D007383:Intermittent Claudication / Q000097:blood / Q000209:etiology* / Q000503:physiopathology; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism*; D010108:Oxyhemoglobins / Q000378:metabolism*; D016491:Peripheral Vascular Diseases / Q000097:blood / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology; D011237:Predictive Value of Tests; D012372:ROC Curve; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D019265:Spectroscopy, Near-Infrared; D018615:Ultrasonography, Doppler, Color
D015415:Biomarkers; D006454:Hemoglobins; D010108:Oxyhemoglobins; C100003:deoxyhemoglobin