USMLE Step 3 - Question 4

A 62 year old male with a history of mitral valve prolapse, rhematoid arhtritis, and colon cancer presents to the emergency room with increased dyspnea on exertion, lower extremity swelling, and fevers slowly worsening over the past month. His temperature is 38.0 C, blood pressure 95/65, heart rate 80, respirations 20, and oxygen saturation 92% on room air. Physical examination reveals normal breath sounds, a II/VI holosystolic murmur at the apex, and 1+ bilateral lower extremity pitting edema. Laboratory studies show a WBC count of 20 thousand and an ESR of 100. A transesophageal  echocardiogram reveals an 8 mm mobile vegitation on the anterior leaflet of the mitral valve. Blood cultures grow Streptococcus bovis and he is treated appropriately with IV antibiotics for endocarditis. Which of the following further diagnostic work-up should be performed?

A. Coronary angiography

B. MRI of the brain

C. Pulmonary function testing

D. Colonoscopy