Instability of the sternum is most indicative of which complication after CABG?

• A. Mediastinitis
• B. Postpericardiotomy syndrome
• C. Deep vein thrombosis
• D. Myocardial infarction

Answer: (A)

Sternal instability after CABG points to a deep infection of the mediastinum, known as mediastinitis. After a sternotomy, the sternum is wired closed, and infection can erode the sternum and disrupt the wiring, causing the halves to separate and feel unstable. This mechanical breakdown is a hallmark of mediastinal infection and signals a serious complication that requires urgent evaluation and treatment. Other postoperative issues don’t typically cause the sternum to become unstable: postpericardiotomy syndrome is an inflammatory reaction around the heart, not a structural breakdown of the sternum; deep vein thrombosis affects the legs and lungs rather than the chest wall; and myocardial infarction presents with ischemic symptoms and enzyme changes, not sternal dehiscence.