Calf muscle hemoglobin oxygen saturation characteristics and exercise performance in patients with intermittent claudication.
OBJECTIVE
This study was conducted to determine the association between the characteristics of calf muscle hemoglobin oxygen saturation (StO(2)) and exercise performance in patients with intermittent claudication.


METHODS
The study comprised 39 patients with peripheral arterial disease limited by intermittent claudication. Patients were characterized on calf muscle StO(2) before, during, and after a graded treadmill test, as well as on demographic and cardiovascular risk factors, ankle-brachial index (ABI), ischemic window, initial claudication distance (ICD), and absolute claudication distance (ACD).


RESULTS
Calf muscle StO(2) decreased 72%, from 55% +/- 18% (mean +/- SD) saturation at rest to the minimum value of 17% +/- 19% saturation attained 459 +/- 380 seconds after the initiation of exercise. After exercise, recovery half-time of calf muscle StO(2) was attained at 129 +/- 98 seconds, whereas full recovery to the resting value was reached at 225 +/- 140 seconds. After adjusting for sex, race, and grouping according to the initial decline constant in calf muscle StO(2) during exercise, the exercise time to minimum calf muscle StO(2) was correlated with the ischemic window (r = -0.493, P = .002), ICD (r = 0.339, P = .043), and ACD (r = 0.680, P < .001). After treadmill exercise, the recovery half-time of calf muscle StO(2) was correlated with the ischemic window (r = 0.531, P < .001), ICD (r = -0.598, P < .001), and ACD (r = -0.491, P = .003).


CONCLUSIONS
In patients limited by intermittent claudication, shorter ICD and ACD values are associated with reaching a minimum value in calf muscle StO(2) sooner during treadmill exercise and with having a delayed recovery in calf muscle StO(2) after exercise.
CMRI Metabolic Research Program, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA. andrew-gardner@ouhsc.edu
Andrew W
AW
Gardner
Donald E
DE
Parker
Nykita
N
Webb
Polly S
PS
Montgomery
Kristy J
KJ
Scott
Steve M
SM
Blevins
D000368:Aged; D000369:Aged, 80 and over; D005080:Exercise Test; D017079:Exercise Tolerance; D005260:Female; D006801:Humans; D007383:Intermittent Claudication / Q000209:etiology / Q000378:metabolism / Q000503:physiopathology*; D007511:Ischemia / Q000209:etiology / Q000378:metabolism / Q000503:physiopathology*; D007866:Leg / Q000098:blood supply*; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction; D018482:Muscle, Skeletal / Q000378:metabolism / Q000503:physiopathology*; D010108:Oxyhemoglobins / Q000378:metabolism*; D016491:Peripheral Vascular Diseases / Q000150:complications / Q000378:metabolism / Q000503:physiopathology*; D020127:Recovery of Function; D013997:Time Factors
D010108:Oxyhemoglobins