Review Question - QID 109790

A 59-year-old man presents to the emergency department with abdominal pain. He states that it seemed to come on abruptly, though he does endorse feeling pain the past several days. He has been experiencing bloody diarrhea as well as a subjective fever. His past medical history is notable for an ST elevation myocardial infarction (STEMI) treated 1 year ago, an abdominal aortic aneurysm (AAA) treated 1 week ago, chronic obstructive pulmonary disease (COPD), asthma, obesity, hypertension, stroke treated 5 years ago, an atrial arrhythmia, diabetes, constipation, and post-traumatic stress disorder (PTSD). His temperature is 102.0°F (39°C), blood pressure is 197/128 mmHg, pulse is 135/min, respirations are 22/min, and oxygen saturation is 92% on room air. On physical exam, you note an obese man in distress. Cardiopulmonary exam is notable for bilateral wheezes and a systolic murmur. There is bilateral lower extremity pitting edema and venous stasis ulcers. Abdominal exam reveals diffuse tenderness which the patient describes as 10/10 in severity. Laboratory values are ordered as seen below.

Hemoglobin: 14 g/dL
Hematocrit: 42%
Leukocyte count: 15,500/mm^3 with normal differential
Platelet count: 199,000/mm^3

Serum:
Na+: 139 mEq/L
Cl-: 100 mEq/L
K+: 4.4 mEq/L
HCO3-: 22 mEq/L
BUN: 32 mg/dL
Glucose: 189 mg/dL
Creatinine: 1.9 mg/dL
Ca2+: 10.2 mg/dL
Lactate: 4.5 mg/dL
AST: 12 U/L
ALT: 10 U/L

Which of the following is the most likely explanation for this patient's presentation?