Q. You are called to evaluate a 61-year-old man who was admitted yesterday to the surgical ward after an abdominal aortic aneurysm repair. The patient has a history of diabetes, hypertension, and atrial fibrillation. He is complaining of pain in his right flank and discomfort in his left leg. The patient's vital signs are blood pressure 155/97 mm Hg, heart rate 94/min, and respiratory rate 12/min. On physical examination, abnormal discoloration is noted in his left lower extremity (see image). Dorsalis pedis pulse is 2 plus bilaterally. Cardiac auscultation reveals no abnormalities. Which of the following pathophysiological mechanisms is most likely responsible for this patient's symptoms?