This question tests USMLE Step 2 CK skills in understanding Pulmonary Vascular Disease and its management. Pulmonary Vascular Disease includes conditions like pulmonary embolism and hypertension, requiring specific diagnostic and management strategies. In this scenario, the vignette provides clinical clues such as post-flight dyspnea and lobar PE with mild RV enlargement, which suggest intermediate-risk pulmonary embolism. Choice B is correct because it aligns with the guideline to anticoagulate and monitor stable patients based on clinical stability. Choice A is incorrect because it fails to address the absence of shock, often leading to overtreatment with thrombolysis. Teaching strategies include emphasizing the importance of recognizing key clinical signs of pulmonary vascular disorders and applying evidence-based management protocols. Encourage practice with differential diagnosis and appropriate test selection.

This question tests USMLE Step 2 CK skills in understanding Pulmonary Vascular Disease and its management. Pulmonary Vascular Disease includes conditions like pulmonary embolism and hypertension, requiring specific diagnostic and management strategies. In this scenario, the vignette provides clinical clues such as prior DVT and V/Q mismatches suggesting CTEPH, which suggest potential for surgical cure. Choice A is correct because it aligns with the guideline to refer for PTE evaluation in operable CTEPH. Choice B is incorrect because it fails to address the thromboembolic cause, often leading to infectious misdiagnosis. Teaching strategies include emphasizing the importance of recognizing key clinical signs of pulmonary vascular disorders and applying evidence-based management protocols. Encourage practice with differential diagnosis and appropriate test selection.

This question tests USMLE Step 2 CK skills in understanding Pulmonary Vascular Disease and its management. Pulmonary Vascular Disease includes conditions like pulmonary embolism and hypertension, requiring specific diagnostic and management strategies. In this scenario, the vignette provides clinical clues such as post-flight PE with recent GI bleed, which suggest high bleeding risk. Choice A is correct because it aligns with the guideline to place IVC filter when anticoagulation is contraindicated. Choice B is incorrect because it fails to address bleeding risk, often leading to avoidance of necessary prevention. Teaching strategies include emphasizing the importance of recognizing key clinical signs of pulmonary vascular disorders and applying evidence-based management protocols. Encourage practice with differential diagnosis and appropriate test selection.

This patient has a low pre-test probability for pulmonary embolism (PE) based on the Wells score of 1.5 (≤4 is low probability). According to diagnostic algorithms, for patients with low clinical probability of PE, the next step is to use a sensitive screening test like a D-dimer assay. A negative D-dimer result in this setting has a high negative predictive value and can effectively rule out PE, avoiding the need for radiation exposure and contrast from imaging. A positive D-dimer would then prompt further imaging.

This patient has a high clinical probability of pulmonary embolism (PE) based on the Wells criteria (recent surgery, tachycardia, clinical signs of DVT). In patients with high pre-test probability, a D-dimer assay is not useful as it has a low negative predictive value and is likely to be positive. The most appropriate next step is definitive diagnostic imaging. CT pulmonary angiography (CTPA) is the gold standard for diagnosing PE in hemodynamically stable patients and should be performed promptly. While a lower extremity ultrasound may confirm a DVT, a negative result does not rule out PE, and CTPA would still be required.

For a hemodynamically stable patient with an acute pulmonary embolism and no significant contraindications (e.g., severe renal or hepatic disease), a direct oral anticoagulant (DOAC) such as rivaroxaban or apixaban is a first-line option and is preferred over vitamin K antagonists. Unfractionated heparin is typically reserved for patients who are hemodynamically unstable, have severe renal insufficiency, or in whom rapid reversal of anticoagulation might be necessary. Thrombolytic therapy is reserved for massive PE with hemodynamic instability. An IVC filter is indicated only if anticoagulation is contraindicated.

This patient presents with a massive pulmonary embolism, which is defined by the presence of hemodynamic instability (hypotension, SBP < 90 mmHg). In the absence of absolute contraindications (e.g., active bleeding, recent hemorrhagic stroke), the treatment of choice is systemic thrombolysis with a tissue plasminogen activator like alteplase. This intervention can rapidly dissolve the clot, reduce right ventricular afterload, and improve hemodynamics. Anticoagulation with heparin alone is insufficient for a massive PE. Delaying treatment for further imaging is inappropriate in a critically ill patient.

For a patient with a first unprovoked venous thromboembolism (VTE), such as this patient's PE, the risk of recurrence after discontinuing anticoagulation is high. Current guidelines recommend extended (indefinite) anticoagulation for these patients, provided their bleeding risk is low to moderate. Apixaban, a DOAC, is an excellent choice for extended therapy. Limiting therapy to 3 or 6 months carries a significant risk of a recurrent, potentially fatal VTE. Aspirin is significantly less effective than anticoagulation for secondary prevention of VTE.

This patient has an absolute contraindication to anticoagulation due to his recent hemorrhagic stroke. In such situations, the primary indication for an inferior vena cava (IVC) filter is to prevent additional thrombi from the lower extremities from embolizing to the pulmonary circulation. Any form of anticoagulation, even at lower doses, would carry an unacceptably high risk of catastrophic intracranial hemorrhage. Surgical embolectomy is an invasive procedure reserved for patients with massive PE who have failed or have contraindications to thrombolysis, not for stable patients.

While the echocardiogram is an excellent screening tool, right heart catheterization is the gold standard for the diagnosis of pulmonary hypertension (PH). It is required to confirm the diagnosis by directly measuring pulmonary artery pressures (mean PA pressure >20 mmHg at rest). It also measures the pulmonary capillary wedge pressure, which is essential to distinguish pre-capillary PH (like pulmonary arterial hypertension associated with connective tissue disease) from post-capillary PH (due to left heart disease). This distinction is critical as the treatments are entirely different.