What is indicated by a calculated ABI result suggesting severe disease?

A calculated Ankle-Brachial Index (ABI) result suggesting severe disease indicates significant arterial insufficiency, typically characterized by a low ABI value. In such cases, the blood flow to the lower extremities is severely compromised, meaning there is a notable risk of further complications like ulcers or limb ischemia. Because compression therapy is intended to increase venous return by applying pressure to the extremities, using it in a patient with severe arterial disease could exacerbate the situation by reducing blood flow even further. Therefore, compression therapy is contraindicated in this scenario to protect against the potential for ischemic events.

The other options do not align with the implications of a low ABI. An increase in blood flow would not be expected with severe arterial disease; instead, blood flow is decreased. Normal venous function is contradicted by severe arterial disease, which suggests compromised blood supply and delivery. Lastly, an effective medication response would not typically be indicated by just calculating the ABI; additional clinical evaluations would be necessary to determine medication efficacy.