Calf DVTs - Unreliable to diagnose: < 70% sensitivity - Unclear significance: 75% resolve without treatment
But what if you find a calf DVT? Plan A: anticoagulate Plan B: ASA only. Monitor for extension (Not all calf veins are equally important)
Clip: calf veins
Is Doppler needed? No. Compression is sufficient. Color can sometimes help identify vessels. Doppler can give false normals: eg non-occlusive DVT has normal augmentation.
Doppler flow info: Augmentation: - squeeze the calf and blood rushes past the probe - implies no obstruction between calf and probe Respiratory phasicity: - implies no obstruction up in pelvis - flow stops on inhale, goes on exhale
Venous flow (note respirations)
phasic flow and augmentation
What is duplex? 2 modalities together: U/S + Doppler