A rising gradient on a transcatheter valve is thrombosis until proved otherwise

Structural degeneration of a transcatheter aortic valve is slow and usually shows itself years after implantation. Leaflet thrombosis is quick, can appear within months, and unlike degeneration it often responds to anticoagulation. The two are easily confused on a follow-up echocardiogram, and the consequence of confusing them is a patient sent for a redo procedure who needed a drug.

The signal to act on is change rather than an absolute number. A mean transvalvular gradient that has climbed appreciably from the patient's own post-implantation baseline, particularly within the first year, and particularly with a rise in leaflet thickness or reduced leaflet motion, should prompt a cardiac CT rather than a repeat echo in six months. This is why the discharge echo matters: without a recorded baseline gradient there is nothing to compare against.

When thrombosis is confirmed and the patient is symptomatic or the gradient is clearly raised, anticoagulation is the treatment and the gradient usually falls. That is a different situation from the asymptomatic leaflet thickening picked up on a screening CT, where the evidence does not support anticoagulating.

• Record and keep the post-implantation baseline mean gradient; every later echo is judged against it
• Investigate a rising gradient in the first year with cardiac CT, not with watchful waiting
• Ask the echocardiographer to comment on leaflet motion and thickness, not only on the gradient
• Separate symptomatic or gradient-raising leaflet thrombosis, which is treated, from incidental leaflet thickening, which is not
• Review adherence to the prescribed antithrombotic regimen before assuming device failure

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