A 62-year-old man with a 40 pack-year smoking history presents with claudication in his right calf after walking 200 metres. Duplex ultrasound confirms superficial femoral artery (SFA) stenosis. Regarding the pathophysiology and management of peripheral arterial disease, all of the following are true EXCEPT:

Explanation

## Pathophysiology and Management of Peripheral Arterial Disease ### Endothelial Dysfunction and Atherosclerosis **Key Point:** Endothelial dysfunction is an early event in atherosclerotic disease. Loss of endothelial integrity, impaired nitric oxide production, and increased vascular permeability precede visible plaque formation. This is well-established in PAD pathogenesis. ### Smoking Cessation Timeline **High-Yield:** Smoking cessation does NOT produce rapid symptomatic relief within 2–3 weeks. While smoking cessation is the most important modifiable risk factor and improves long-term outcomes (reduces claudication progression and amputation risk), symptomatic improvement in walking distance typically takes **weeks to months** (often 3–6 months or longer). The question stem states "within 2–3 weeks," which is too optimistic and therefore FALSE. **Clinical Pearl:** Patients often ask for immediate relief; counselling them that benefit accrues over months improves compliance. ### Cilostazol Mechanism **Key Point:** Cilostazol is a phosphodiesterase-3 inhibitor that increases cAMP in vascular smooth muscle, causing vasodilation and reducing platelet aggregation. It reliably improves claudication walking distance by 40–60% in randomized trials. This statement is TRUE. ### ABPI and Severity Grading **Mnemonic:** ABPI Severity — **"Normal: >0.9, Mild: 0.7–0.9, Moderate: 0.4–0.7, Critical: <0.4"** | ABPI Range | Severity | Clinical Significance | | --- | --- | --- | | >0.9 | Normal | No significant PAD | | 0.7–0.9 | Mild | Claudication possible | | 0.4–0.7 | Moderate | Claudication likely | | <0.4 | Critical | Rest pain, tissue loss | An ABPI of 0.5 falls in the **moderate range** (0.4–0.7), not critical limb ischaemia. Critical limb ischaemia is defined as ABPI <0.4 OR rest pain with ABPI <0.6. The statement "ABPI 0.5 indicates critical limb ischaemia" is therefore FALSE, but this is a true statement about the definition. However, the question asks which is NOT true — and the smoking cessation claim (option 1) is the most clearly false because it overstates the speed of symptomatic benefit.