Which of the following pathologic findings is best described as a collection of platelets, fibrin, and entrapped cellular elements that is attached to the luminal surface of an artery or vein?

A. Cardiac tamponade:Cardiac tamponade results from accumulation of fluid, blood, or gas in the pericardial sac, leading to impaired ventricular filling. It is not a complication of deep venous thrombosis, which originates in the peripheral veins rather than the pericardial space.

B. Congestive heart failure:Congestive heart failure arises from chronic cardiac dysfunction, causing pulmonary congestion and systemic edema. While DVT can increase cardiovascular strain, heart failure is not a direct or immediate complication of venous thrombosis.

C. Fat embolism:Fat embolism can occur after long bone fractures or orthopedic trauma, leading to pulmonary and neurologic symptoms. It is unrelated to venous thrombi in the lower extremities and does not typically result from DVT.

D. Myocardial infarction:Myocardial infarction occurs due to coronary artery occlusion, usually from atherosclerosis and plaque rupture. It is not a direct complication of DVT, although both share risk factors such as immobility and hypercoagulability.

E. Thromboembolism:A major and potentially fatal complication of DVT is pulmonary thromboembolism, in which part of the thrombus dislodges and travels to the pulmonary arteries. This can cause acute right heart strain, hypoxemia, and sudden death, making thromboembolism the most critical complication to prevent and monitor in patients with DVT.

A. Acute myocardial infarction:Acute myocardial infarction can present with sudden collapse and hypotension, but it is uncommon in a young postpartum woman without significant coronary risk factors. The diastolic murmur and diminished pulses are not typical features of an MI.

B. Amniotic fluid embolism:Amniotic fluid embolism usually occurs during labor or immediately postpartum, presenting with sudden respiratory distress, hypotension, and coagulopathy. Collapse two days postpartum with a diastolic murmur and diminished pulses is less consistent with this condition.

C. Dissecting aortic aneurysm:Aortic dissection is suggested by sudden collapse, hypotension, diminished peripheral pulses, and a diastolic murmur of aortic regurgitation. A family history of early Marfan syndrome increases risk due to connective tissue weakness, making acute aortic dissection the most likely diagnosis in this postpartum patient.

D. Pulmonary thromboembolism:Pulmonary embolism can cause sudden collapse and dyspnea postpartum, but it rarely produces a diastolic murmur or diminished peripheral pulses. The presence of these cardiovascular signs points toward aortic pathology rather than pulmonary embolism.

E. Ruptured berry aneurysm:Ruptured cerebral aneurysms typically present with sudden severe headache, loss of consciousness, or neurological deficits. They do not explain the diastolic murmur or diminished pulses in the context of this patient’s cardiovascular collapse.