Abstract 13381: The Relationship Between PAD Symptomatology and Ischemia: a Mixed Method Evaluation
Introduction: Classic claudication is only reported by 7.5% to 33% of patients with PAD. Atypical symptom reporting is common, but it is unknown if ischemic changes are occurring since the relationship between atypical symptoms and tissue oxygen saturation (StO2) has not previously been reported. The purpose of this study was to measure calf StO2 during treadmill exercise and recovery, and evaluate its relationship with self-reported symptoms.
Methods: Adults diagnosed with PAD and experiencing exercise-limiting ischemic symptoms were asked to: (a) use a numeric rating scale (0 to 5) to rate symptoms during exercise and recovery; (b) provide symptom descriptors; and (c) wear a near-infrared spectroscopy device to obtain calf StO2 during exercise and recovery. Data analysis included descriptive statistics, exploration of individual and grouped graphical trajectories, and multilevel modeling.
Results: During three successive bouts of treadmill exercise, 40 participants (80% Caucasian males, mean age 68±9 years) provided 22 symptom descriptors in eight lower extremity locations. Only 69.2% of exercise tests were stopped due to discomfort in the calf and classic descriptors were used only half the time to describe maximum calf discomfort (55.4%). The most rapid decline in StO2 during exercise occurred between the start of exercise and the onset of symptoms. The nadir StO2 was often reached prior to the report of maximum discomfort. In the exercise model, changes in StO2 were related to total exercise time (p<0.001), baseline StO2 (p<0.001), exercise ratings (p<0.001) and ABI (p<0.05). During recovery, StO2 increased steadily for most participants between maximum discomfort and full symptom recovery; changes in StO2 were related to recovery ratings (p<0.001) and ABI (p<0.03).
Conclusions: Ischemic symptoms extended beyond classic locations and descriptors. Interestingly, participant perception of maximum discomfort frequently occurred after the nadir StO2. Similarly, most reports of full symptom recovery occurred prior to complete resolution of ischemia. Further research is necessary to explore mechanisms that could explain this objective-subjective mismatch to better understand the full range of ischemic symptoms associated with PAD.
Author Disclosures: E. Schorr: None. D. Treat-Jacobson: None. K. Savik: None. R. Lindquist: None.
- © 2014 by American Heart Association, Inc.