What condition is most likely suggested by complaints of chronic unilateral lower extremity swelling, aching, and a sense of heaviness?

The condition suggested by complaints of chronic unilateral lower extremity swelling, aching, and a sense of heaviness aligns well with postphlebitic syndrome. This syndrome occurs as a long-term consequence of deep vein thrombosis (DVT) and is typically characterized by persistent leg symptoms following the swelling and discomfort associated with a previous venous thrombosis.

Chronic venous insufficiency, another potential option, often presents differently by involving symptoms in both legs due to venous valve incompetence over time, not strictly unilateral. It can also manifest with chronic swelling and skin changes, but the key feature of unilateral symptoms aligns more closely with postphlebitic syndrome, particularly when there’s a known DVT history.

Deep vein thrombosis would typically present with acute symptoms, such as sudden unilateral swelling and pain, rather than chronic complaints. This makes it less likely to match the description in the question.

Peripheral artery disease generally causes symptoms related to arterial blockage, such as leg pain during activity, known as claudication, which again does not reflect the swelling or heaviness noted in the scenario.

Thus, the nature of the symptoms and their chronic presentation strongly indicate postphlebitic syndrome as the most fitting condition.