Final answer:
Severe or symptomatic PAD patients are referred for PCI or surgery to manage the condition when lifestyle changes and medication do not suffice, especially in critical cases like CLI, to prevent limb loss and mitigate myocardial infarction or stroke risks.
Step-by-step explanation:
Patients with Peripheral Artery Disease (PAD) who may be referred for Percutaneous Coronary Intervention (PCI) or surgery are typically those with severe and/or symptomatic PAD. PCI or surgical intervention, such as angioplasty with stent placement or bypass surgery, is considered when lifestyle changes and medication do not sufficiently improve symptoms or in cases of critical limb ischemia (CLI), where there is a risk of limb loss. CLI presents with more severe symptoms such as non-healing ulcers or gangrene due to the severely decreased blood flow in the extremities. In such scenarios, surgery is often necessary to restore adequate blood flow. Moreover, patients with PAD are at higher risk of myocardial infarction or stroke due to underlying atherosclerosis, thus making prompt and effective treatment crucial.