A 72-year-old man with metastatic prostate cancer comes to the emergency department with shortness of breath and chest pain. His right side hurts when he takes deep breaths. His symptoms started 7 hours ago when he went to bed and could not fall asleep. The patient's baseline exercise tolerance is limited due to exertional dyspnea, but this is the first time he has experienced dyspnea at rest. His other medical problems include hypertension, chronic kidney disease, and colonic diverticular bleeding several years ago. He is a lifetime nonsmoker and does not use alcohol or injection drugs.
Temperature is 36.7 C (98 F) , blood pressure is 162/98 mm Hg, pulse is 112/min and regular, and respirations are 20/min. BMI is 30 kg/m². Oxygen saturation is 87% on room air. Auscultation reveals normal heart sounds with no murmurs and clear lungs. The patient has bilateral 1+ pedal edema. Stool occult blood testing is negative.
Laboratory results are as follows:
ECG shows sinus tachycardia but is otherwise unremarkable. Supplemental oxygen by nasal cannula is initiated and intravenous heparin infusion is started due to high clinical suspicion of pulmonary embolus. Ventilation perfusion scan is performed and shows intermediate probability.
Which of the following is the best next step in management of this patient?

Question

A 72-year-old man with metastatic prostate cancer comes to the emergency department with shortness of breath and chest pain. His right side hurts when he takes deep breaths. His symptoms started 7 hours ago when he went to bed and could not fall asleep. The patient's baseline exercise tolerance is limited due to exertional dyspnea, but this is the first time he has experienced dyspnea at rest. His other medical problems include hypertension, chronic kidney disease, and colonic diverticular bleeding several years ago. He is a lifetime nonsmoker and does not use alcohol or injection drugs.
Temperature is 36.7 C (98 F) , blood pressure is 162/98 mm Hg, pulse is 112/min and regular, and respirations are 20/min. BMI is 30 kg/m². Oxygen saturation is 87% on room air. Auscultation reveals normal heart sounds with no murmurs and clear lungs. The patient has bilateral 1+ pedal edema. Stool occult blood testing is negative.
Laboratory results are as follows:

ECG shows sinus tachycardia but is otherwise unremarkable. Supplemental oxygen by nasal cannula is initiated and intravenous heparin infusion is started due to high clinical suspicion of pulmonary embolus. Ventilation perfusion scan is performed and shows intermediate probability.
Which of the following is the best next step in management of this patient?

Quizplus · Accepted Answer

11ec193a_96a0_a2f0_853d_75b0f0cbe8e1_MD0002_00 This patient with active malignancy, tachycardia, dyspnea, and pleuritic chest pain has high pretest probability for acute pulmonary embolism (PE). CT angiography of the chest is the test of choice to evaluate for acute PE; however, intravenous contrast administration is contraindicated due to chronic kidney disease (CKD). Therefore, ventilation-perfusion (V/Q) scan is most appropriate. high pretest probability In the setting of high pretest probability for PE, a normal V/Q scan rules out PE and a high-probability V/Q scan confirms PE. Any other V/Q scan result (eg, intermediate probability) is nondiagnostic. In patients at average bleeding risk with high pretest probability for PE, inability to undergo CT angiography, and a nondiagnostic V/Q scan, empiric anticoagulation treatment (Choice D) is often appropriate as further testing is unlikely to change management. However, this patient has multiple risk factors for bleeding complications (ie, hypertension, CKD, previous gastrointestinal bleeding), and commitment to long-term anticoagulation cannot be taken lightly. Therefore, additional diagnostic information will aid in the risk/benefit analysis. Lower extremity ultrasound is a noninvasive and relatively inexpensive method of obtaining additional diagnostic information. Although a negative result does not rule out PE in the setting of high pretest probability, a positive result confirms venous thromboembolic disease and tips the risk/benefit analysis strongly in favor of long-term anticoagulation. (Choice A) Catheter-based pulmonary angiography is the historical gold standard for diagnosis of acute PE; however, it is rarely performed due to the invasiveness of testing. In addition, it requires intravenous contrast, which is not appropriate for this patient with CKD. (Choice B) This patient has high clinical probability of PE; heparin should not be discontinued until PE is either ruled out or it is determined that the benefits of long-term anticoagulation for treating a suspected (but not confirmed) PE are outweighed by the risks, and an inferior vena cava filter is placed. (Choice C) High-sensitivity D-dimer assay can effectively rule out PE in patients with low pretest probability; however, the false-negative rate is unacceptably high in those with high pretest probability. In addition, malignancy often raises D-dimer levels and renders the assay non-useful. Educational objective: In the setting of high pretest probability for acute pulmonary embolism, a low-probability or intermediate-probability ventilation-perfusion scan result is nondiagnostic. In patients with elevated bleeding risk, additional testing (eg, lower-extremity ultrasound) is indicated following such a result to further aid the risk/benefit analysis of long-term anticoagulation. __________ References: Multidetector computed tomography for acute pulmonary embolism. (http://www.ncbi.nlm.nih.gov/pubmed/16738268) Guidance for the treatment of deep vein thrombosis and pulmonary embolism. (http://www.ncbi.nlm.nih.gov/pubmed/26780738)

A 72-Year-Old Man with Metastatic Prostate Cancer Comes to the Emergency