Internal Medicine

P1: SBT

0521779407-04 CUNY1086/Karliner 0 521 77940 7 June 13, 2007 7:8

142 Aortic Dissection

➣Direct vasodilators (hydralazine, diazoxide) are contraindicated

because they increase shear and may propagate dissection

Side Effects & Contraindications

■Surgery

➣Side effects: major hemorrhage, stroke, MI, spinal cord injury,

sepsis, death (15–20% perioperatively)

Contraindications

relative: emergent need-surgical risk may decrease after several

days of medical stabilization (confounded by culling effect)

■Beta blockers

➣Side effects: dizziness, tiredness, severe bradycardia, hypoten-

sion, rales, bronchospasm, heart block.

➣Contraindications

Absolute: cardiogenic shock, severe COPD

➣Relative: heart rate <45, AV conduction defects, COPD

■Sodium Nitroprusside

➣Side effects: precipitous drop of BP with accompanying sequelae,

cyanide toxicity-risk increases with dose, duration of therapy-

monitor thiocyanate levels

➣Contraindications

Absolute: continued infusion beyond 10 minutes at maximum

dose

Relative: renal or liver impairment, hypothyroidism, hypona-

tremia, B12 deficiency, increased intracranial pressure, hypo-

volemia, thiosulfate thiotransferase deficiency (congenital

Leber’s optic atrophy, tobacco amblyopia)

follow-up

■If nitroprusside is used, thiocyanate levels must be followed closely.

Metabolic acidosis is also a (delayed) indication of Cyanide toxicity.

■Monitor patients for propagation with end organ effects which may

be indication for surgery even in type III.

complications and prognosis

■Complications: tamponade, renal failure, bowel ischemia, stroke, MI,

death, sepsis, paraplegia

■Prognosis: In-hospital mortality of surgically managed type A dis-

section is 15–20%. In-hospital mortality of medically managed type

B dissection is also 15–20%. 10 year survival for non-Marfan’s aortic

dissection is 60%, worse in Marfan’s