It’s not just blood pressure…it’s poor impulse control! • dP/dt • Change in pressure per Unit of time
Anti-impulse therapy • Negative inotropy (and thus rate of rise of blood pressure, as well as mean and peak systolic pressure) • Negative chronotropy (fewer peak systolic pressures for the vulnerable vessel to experience) • Alpha blockade (prevent compensatory vasoconstriction) Goal blood pressure: as low as possible without inducing organ failure….Systolic BP of 100, or MAP of 60-70. No great evidence; this would be a tough population to ethically randomize.
Pharmacologic options: with invasive monitoring • Esmolol: Beta blocker, bolus and infusion options • 1 mg/kg (usually about 80 mg) bolus • 150-300 mcg/kg/min • Labetalol: alpha-antagonistic properties • 20 mg IV bolus (may require up to 80 mg over 10 min) • 0.5-6 mg/min infusion • Propranolol: 1-10 mg bolus, followed by 3 mg/hr
Others • Nitroprusside: beware cyanide toxicity (at about 500 mcg/kg). Do not use without beta-blockade (reflex tachycardia) • 0.5 mcg/kg/min, titrate in 0.5 increments to max 10 mcg/kg/min • ACE inhibitors may be used, but given the high risk of renal failure, and unreliable gut function depending upon the course of the dissection, they would not be plan A. • For patients who cannot tolerate beta blockers, non-DHP calcium channel blockers (verapamil or diltiazem) are viable options.
Classification systems for Thoracic Aortic Dissections • Time course: Acute vs. Chronic • Anatomical: Ascending, descending or both • Stanford: • Type A: Involving the ascending aorta (with or without descending aortic involvement) • Type B: Involving only the descending aorta • De Bakey: • I: Ascending and Descending aorta • II: Ascending Aorta only • III: Descending Aorta only