Clinical meaning
Inflammation leads to upregulation of MMPs which degrade elastin and collagen in the aortic media. This structural weakening, combined with LaPlace's Law (Wall Tension = Pressure x Radius), creates a cycle of dilation. Rupture occurs when wall stress exceeds tensile strength.
Diagnosis & workup
Diagnostics & workup: - Order CT angiography (CTA) for definitive diagnosis and surgical planning - Order bedside ultrasound for rapid screening (diameter measurement) - Order CBC, type and crossmatch, coagulation studies STAT for suspected rupture - Order BMP and lactate to assess perfusion and acidosis - Order arterial blood gas for acid-base status - Order serial abdominal imaging to monitor growth rate (>0.5 cm/year is concerning) - Order preoperative cardiac risk assessment (stress testing if stable)
Risk factors: - Age > 65 with smoking history - Male sex - First-degree relative with AAA - Peripheral vascular disease - Hypertension - Hyperlipidemia - COPD - Connective tissue disorders