A 71-year-old man comes to the emergency department for 3 hours of sudden-onset, severe lower abdominal and back pain with lightheadedness. He has hypertension and hyperlipidemia and has smoked 1.5 packs of cigarettes daily for 50 years; he continues to smoke. On exam, he is diaphoretic and pale. Temperature is 36.8°C (98.2°F), blood pressure is 88/54 mm Hg, pulse is 126/min, and respirations are 22/min. Abdominal exam reveals a tender, pulsatile mass just above the umbilicus. Point-of-care ultrasound shows an abdominal aortic aneurysm measuring 6.8 cm in diameter with surrounding free fluid.

Which of the following is among the strongest predictors of rupture for this patient’s condition?