A 58-year-old man with diabetes and hypertension undergoes duplex ultrasound for suspected lower limb PAD. Regarding the investigations, diagnostic criteria, and management of peripheral arterial disease, all of the following statements are true EXCEPT:

Explanation

## Peripheral Arterial Disease: Investigations & Medical Management ### Role of Cilostazol in PAD **Key Point:** Cilostazol is **not contraindicated in all PAD patients**. It is a phosphodiesterase-3 inhibitor that improves claudication symptoms by increasing cAMP, enhancing vasodilation and platelet inhibition. However, it is **contraindicated in patients with heart failure** (particularly systolic HF) because it increases mortality in that population. In claudication without HF, cilostazol is an effective second-line agent. **High-Yield:** Cilostazol improves claudication walking distance by ~50% in clinical trials and is recommended by major guidelines (ACC/AHA) for symptomatic PAD when aspirin alone is insufficient [cite:Harrison 21e Ch 297]. **Warning:** The statement "cilostazol should never be used" is **false**. It is a valuable agent in the right patient population (claudication, no HF). ### Why the Other Options Are Correct | Statement | Validity | |-----------|----------| | **Duplex ultrasound** | True. First-line non-invasive imaging; sensitivity ~85–95% and specificity ~90–95% for >50% stenosis. Peak systolic velocity (PSV) ratio >2.0 suggests >50% stenosis | | **CTA & MRA** | True. Reserved for inconclusive duplex or preoperative planning. CTA risk: contrast-induced nephropathy (especially in renal impairment). MRA risk: gadolinium deposition (concern in renal failure) | | **Critical limb ischemia** | True. Defined by Rutherford category 4–6: rest pain, tissue loss, gangrene. Requires urgent revascularization or amputation to prevent limb loss and systemic infection | ### Diagnostic & Management Hierarchy ```mermaid flowchart TD A[Suspected PAD]:::outcome --> B[ABI + clinical assessment]:::action B --> C{ABI <0.9?}:::decision C -->|Yes| D[Duplex ultrasound]:::action D --> E{Duplex conclusive?}:::decision E -->|Yes| F[Grade severity & plan management]:::action E -->|No| G[CTA or MRA for detail]:::action F --> H{Claudication or CLI?}:::decision H -->|Claudication| I[Conservative: aspirin, statin, exercise]:::action H -->|Refractory claudication| J[Add cilostazol if no HF]:::action H -->|CLI| K[Urgent angiography + revascularization]:::urgent ``` ### Pharmacotherapy in PAD | Agent | Mechanism | Indication | Caution | |-------|-----------|-----------|----------| | **Aspirin** | Antiplatelet | All PAD | Bleeding risk | | **Clopidogrel** | P2Y12 inhibitor | Alternative if aspirin intolerant | Bleeding risk | | **Cilostazol** | PDE-3 inhibitor | Claudication (2nd-line) | **Contraindicated in systolic HF** | | **Statins** | Lipid-lowering, plaque stabilization | All PAD | Myopathy risk | | **ACE inhibitors** | Cardioprotection | All PAD (especially with CAD/DM) | Hyperkalemia, renal impairment | **Mnemonic:** **ASSC** for PAD medical management = **A**spirin, **S**tatins, **S**moking cessation, **C**ilostazol (if claudication, no HF). **Clinical Pearl:** Cilostazol improves walking distance by ~25–50% compared to placebo and is cost-effective for symptomatic claudication. It should be offered before considering invasive revascularization in refractory cases.