Aortic Dissection

We classify aortic dissection as ascending and descending, but there are actually classification schemes with slightly more nuance. The two main classifications are Stanford and DeBakey. Stanford is broken into A (ascending) and B (descending). DeBakey into I (all the way from the ascending down the arch as well), II (ascending only), and III (descending only). Understanding these classifications makes it easier to visualize what’s going on when the CT surgeon calls to admit a patient to the ICU. Sometimes these are surgical emergencies (most commonly Stanford A or DeBakey I and II) but a lot of the time they can be managed conservatively. Conservative management is mainly with impulse control, by keeping the heart rate and blood pressure down. Blood pressure control makes intuitive sense, reduced pressure means less force on the wall of the aorta weakened by the dissection. Heart rate control is a little less obvious, but if you’ve ever seen a heart beating in an open chest, you know that with every beat, the heart twists slightly. This leads to shearing forces that can exacerbate the dissection.

Impulse control may be accomplished by an infusion of esmolol, but increasingly, drips like nicardipine are added for blood pressure control, as esmolol typically doesn’t really control profound hypertension all that well. Esmolol commonly requires a larger volume of fluid because of the dosing and way the drip is made. So, nicardipine in combination with intermittent dosing of metoprolol may be beneficial in patients who can’t tolerate the larger IV volumes.

Count Backwards from 10, has this nice graphic to sum up aortic dissection classification.