House history of increasingly severe low back pain with radiation

A 72 year old man is brought to the ED becuase of a 1 house history of increasingly severe low back pain with radiation into the left flank. He has a long standing history of mild systeolic hypertension and angina pectoris. A pulsatile mass is palpable just inferior to the umbilicus.

Over the next 2 days, his hematocrit decreases from 42% to 28%. He suddenly beceomes hypotensive and dies. Which of the following is the most likely cause of death?