Abstract
Background: After deep vein thrombosis (DVT), local symptoms of chronic venous insufficiency are well described, but little is known about the effect of post-thrombotic venous obstruction on exercise capacity.
Hypothesis: Chronic residual venous occlusion after DVT may cause reduced exercise capacity.
Methods: Subjects were 6 post-DVT patients with residual iliofemoral vein occlusion and effort intolerance, with no cause identified by standard workup; controls were 8 healthy volunteers. Exercise tolerance was assessed by bimodality incremental symptom-limited cardiopulmonary testing, using leg or arm ergometers. Leg vein obstruction was modeled by application to the thighs of cuff tourniquets inflated to 30mmHg. Results are median (range).
Results: Leg exercise tolerance as measured by oxygen consumption at peak exercise (peak V'O2) was reduced (46% predicted (36-67%) in patients vs 89% (77-130%) in controls, p=0.007). Arm exercise tolerance was also reduced, but less severely than in the legs - the arm:leg ratio of peak V'O2 was 1.14 (0.77-1.43) in patients vs 0.71 (0.6-1.0) in controls, p<0.003. In controls, bilateral leg vein obstruction by tourniquets reduced peak V'O2 in leg exercise to 76% predicted (55-106%) vs 89% (77-130%) in the standard test, p<0.05.
Conclusions: The comparison of exercise capacity in arm vs leg exercise of post-DVT patients with residual iliofemoral vein occlusion; and the effect of experimental venous obstruction (thigh tourniquets) in healthy controls; suggest that reduced exercise capacity in patients was at least partially caused by reduced venous return, as simulated in controls. Chronic venous obstruction should be recognized as an exercise limiting factor.
- © 2014 ERS