Clinical meaning
The nurse must understand TAA classification, surveillance protocols, and acute dissection management. TAA is classified by location: ascending aorta (most common site, 60%), aortic arch (10%), descending thoracic aorta (30%). The Stanford classification of aortic dissection divides into Type A (involving the ascending aorta regardless of origin -- surgical emergency) and Type B (NOT involving the ascending aorta -- typically medical management unless complicated). The DeBakey classification is more specific: Type I (ascending and descending), Type II (ascending only), Type III (descending only). Acute aortic dissection involves a tear in the intimal layer creating a false lumen within the aortic media. Blood enters the false lumen and may propagate antegrade or retrograde, potentially occluding branch vessels (malperfusion) or rupturing through the adventitia (free rupture). Malperfusion syndromes depend on which branch vessels are compromised: carotid (stroke), coronary (MI -- usually RCA causing inferior STEMI), subclavian (arm ischemia, BP differential), celiac/SMA (mesenteric ischemia), renal (AKI), iliac (limb ischemia). The nurse manages hemodynamic control targeting SBP below 120 mmHg and HR below 60 bpm, monitors for malperfusion, and coordinates emergent surgical consultation.