dissecting aortic aneurysm.

first of all i love how aneurysm is spelled. that shit looks like the name of a pokemon.

read an ecg second of all, aortic dissection is a break in the lining of the aorta. it’s easy enough. it speaks for itself. it is self-explanatory, right?

before it fully dissects, there’s a tear in the aortic intima, which is the layer of the vessel closest to the inside. intima = intimate. the tear in the intima causes blood to collect inside of a false lumen, like a little pouch in between the layers of the aorta capsule thingy. the dissection can then travel up or down the aorta and affect arteries that extend from the aorta.

this happens to 4 out of every 100,000 people per year. that seems really rare to me. one in 25,000? right, math, math...

we classify aortic dissections as type A when they involve the ascending aorta and type B when they don’t involve the ascending aorta. i think type A is way more serious.

risk factors for dissection include hypertension, connective tissue disease (like marfan’s), vascular inflammation, trauma, as well as iatrogenic causes. iatrogenic means it’s something “we” did that caused it. the doctor gives you something or provides some intervention, and that intervention is the cause of some problem. iatrogenic. cool word.

80% of all dissections happen without a preexisting aneurysm. they just happen, just like that, i guess!!! damn!

the primary symptom is sudden chest pain. this happens 85% of the time. the pain feels worst when it starts, right when it starts. 10% of patients have no pain. that’s scary!!! another silent killer sometimes, but usually this one is a loud killer.

something about a valve when we do a physical exam, we want to see if there’s a diastolic murmur due to aortic insufficiency. i’m not sure why we would do that but they have it here written, and it’s a nice reminder that aortic insufficiency causes a diastolic murmur which is easy to miss on initial exam, i guess?

a cute infarction dissection can cause death when it extends into the pericardium and produces tamponade. too much fluid in the uhhhh lining of the heart. the dissection can also extend to the coronary arteries, god forbid, which can lead to a myocardial infarction. it can also cause an acute aortic insufficiency which can cause heart failure.

the first thing we do to evaluate for dissection is to get a CT of the abdomen. that will reveal the aneurysm or the dissection if it’s there.

type A dissections give you a 91% chance of dying within a week if you don’t get it treated. emergency surgery is necessary, therefore, for type A.

type B has a better prognosis if you don’t have symptoms. you can just treat it medically with blood pressure control. cuz we said hypertension is a risk factor, remember? and i guess that makes sense because like… yeah, i guess if you have too much pressure inside of your blood vessels it might predispose you to a tear, and then the blood makes the false lumen and then you get the dissection, right, right.

wait, just a little note to myself, i think.... i used to consider that like... dissection meant that the aorta gets like fully ripped in half. but i think the implication that i’m arriving at here is that it’s like a dissection as in... like the layers peel back? like it’s not necessarily a full-thickness tear, is it, it’s just the intima separating from the other layers? let’s wait and see, maybe they’ll tell us more.

yes, okay, in this definition here it’s saying that the national library of medicine states that there is a tear in the intima which causes interstitial hemorrhage and dissecting of the vessel wall. it’s a dissection, specifically, between the intima and media (the middle layer of the aorta).

bloons more definitions. an aneurysm is a permanent localized dilatation of an artery. defined as a >50% increase in diameter. it’s just like a swelling of a vessel. ballooning of it, you might say. remember, like when we talked about AAA? it’s like that.

there’s also pseudoaneurysm, which is when uhh....... the arterial wall is disrupted and blood comes out of it and causes a hematoma. i don’t wanna get into that one. i’ll leave that one be.

ectasia, they also want to define for some reason? this is an arterial dilatation less than 150 percent of nomal diameter. what’s the point of that? like defining that as its own word?

notably, and i was wondering about this, dissection can occur without aneurysm, and an aneurysm can occur without dissection. but sometimes they go together. apparently the term “dissecting aortic aneurysm” is often used incorrectly and we’re only supposed to use it when the dissection occurs IN an aneurysm. so like if it’s just a plain old dissection we don’t refer to it as an aneurysmal dissection. that seems obvious but whatever i’m not a doctor.

other things, other things. yes, 4 in 100,000 people per year...... the intima tears and allows blood to dissect the aorta into a false lumen... creates a second hole in which blood can go... and that swells into an aneurysm, right...... sure, okay, now they’re just talking about type A and B again. right, got that one.

risk factors, we said, include hypertension. the reason is because there is necrosis of arterial smooth muscle cells and fibrotic changes of elastic structures in the aortic wall. the compliance of the aorta increases, so it gets more floppy, and the pulsation of the aorta becomes more likely to cause dissection. this risk is further increased by smoking, lipid abnormalities, and cocaine use. another risk factor is connective tissue disease like marfan’s, as we already said. because yeah, these also make the aorta a little too elastic. elasticity makes it more likely for the intima to tear, sure, makes sense. and then there’s vascular inflammation, right, and trauma, iatrogenic, and intramural hematoma.... yes, all these make sense...

the pathogenesis, are we going to rehash this? it’s a separation of the walls creating a false lumen. dissection comes after that. 80% of dissections happen in the absence of a pre-existing aneurysm. they love writing the same information twice. but i suppose i like it cuz it shows me what’s important.

what about when the patient is right in front of you? ask them if they’re having chest pain, and if it started suddenly, and if it was maximal when it first started. this is a symptom in 85% of type A dissection patients. ask if it radiates to their neck, in which case it’s a problem in the ascending aorta, and ask if it radiates to the back between their shoulderblades, which would make it a descending dissection. remember that 10% of patients have no pain. about half of patients have back pain, a quarter have abdominal pain, some have syncope, some have cerebrovascular events. the mortality rate is 2% per hour. scary that they measure it by hour... sheesh!

type B symptoms could be the ones listed above and could also include abdominal pain, ischemic legs... and it has a 30 day mortality rate of 10%.

on physical, look for that diastolic murmur from aortic insufficiency... i guess the dissection can lead to aortic insufficiency? i guess that would make sense, the blood just like falls back into the heart from the false lumen, maybe? shit idk. look also for pulse deficits like weak or absent carotid, brachial, or femoral pulses. if there’s a pulse deficit, your patient is having vascular compromise and has a higher potential for ischemia in their brain and limbs. danger!!!

death can result from dissection into pericardium or coronary arteries or acute aortic insufficiency. the point here is that the dissection wants to keep dissecting, like how when you... like when you rip a paper it wants to keep on ripping i guess. yeah, it wants to keep going and it can even get up close and personal with the heart. and then you can die.

so imagine your patient has sudden onset chest pain. we think of dissection, of course, but we also might be wanting to rule out pulmonary emboli, pericarditis, acute coronary syndrome, costochondritis (regular muscle pain), or a compression fracture. yeah!

and don’t forget CT abdomen is first-line for diagnosis! chest xray and ecg don’t help us! on CT, look for an intimal flap. you’ll see a pretty hard line in the aorta where the dissection has occurred. it’s pretty easy to spot on CT.

like we said, type A dissection needs an emergency surgery. you replace the affected parts of the aorta. replace? with what?? i don’t know but we move on. you may also need to replace the aortic valve and do a coronary bypass, right, if the dissection extends close to the heart. the surgical mortality rate is 25%. that seems high! but i guess it’s better than 100%? like if you don’t get surgery...

if it’s type B, we just treat it with blood pressure control. we want that systolic, that top number of the BP to be between 110 and 120. give beta blockers or nitroprusside, or alternatively you can try diltiazem or verapamil. long term management with beta blockers should keep the systolic blood pressure below 135. we don’t want that thing to get any bigger.

prognosis finale. type A has a 91% mortality rate within a WEEK if you don’t get that surgery. type B has better prognosis if you don’t have symptoms. 40% chance of surviving the year without surgery. that seems a little low... but i guess shows you the scope of the problem here. it’s a big problem. big solutions required.

but hey, that’s it. that wasn’t so bad. not too painful. we can do this. we can keep going! it’s all right! let’s just move right along, right? the next thing, what’s the next thing? still in heart world..... let’s see it.