Does an anterior STEMI rule out dissection?

Well… errr… no. Sorry about that. Mea culpa.

I was idly fulfilling my Irish stereotype planting potatoes in the back garden (seriously…) while listening to an old EM:RAP and listening to a discussion of cath lab activations and STEMI and aortic dissection. The legend that is Stuart Swadron was saying that if it’s an anterior STEMI in front of you then it’s not an aortic dissection. The obvious reason being that an aortic dissection extending into the left main coronary will kill you before you get a chance to get an ECG. (may 2010 at 2hr 10 mins if you’re interested)

This was a pearl so onto twitter it goes. To be greeted with lots of interested replies wondering if it was really true. Within minutes someone had pointed out that they’d seen a case presented of an aortic dissection that presented with a left main STEMI.

So perhaps i was a little precipitous with my “evidence based tweeting.”

Anyhow here are the results of my PubMed searches. References and all if you’re really keen.

The IRAD registry is a big registry of aortic dissection. Type A and B. The famous study is this one:

Hagan PG, Nienaber CA, Isselbacher EM, Bruckman D, Karavite DJ, Russman PL, et al. The International Registry of Acute Aortic Dissection (IRAD): new insights into an old disease. JAMA. 2000 Feb. 16;283(7):897–903. PMID 10685714

But did you know there’s a whole bunch more papers. Check them out here.

One of the things the IRAD registry doesn’t give us is a breakdown of ECG changes and coronary involvements. They tell us if they had “Myocardial infarction, new Q waves or ST segments” but not breakdowns of territories involved.

This abstract might:

Bossone E, Mehta RH, Trimarchi S, Cooper JV, Smith DE, Evangelista A, Myrmel T, Oh J, Nienaber CA, Eagle KA, Isselbacher EM. Coronary artery involvement in patients with acute type A aortic dissection: clinical characteristics and in-hospital outcomes. J Am Coll Cardiol 2003; 41:235A.

But I can’t get access to it anywhere. it’s in the supplements on JACC but they don’t seem to appear on the JACC website…

[UPDATE – Thomas Tschoellitsch pointed me in the right direction and I managed to get a copy of the abstract. in the end it wasn’t that helpful. IRAD obviously didn’t record this…]

However there is some other info that might help us get some idea of what’s happening.

Here’s an odd one:

Hirata K, Kyushima M, Asato H. Electrocardiographic abnormalities in patients with acute aortic dissection. Am. J. Cardiol. 1995 Dec. 1;76(16):1207–1212. PMID 7484916

Dodgy chart review of folk with dissections. 4/49 had STEMI. All anterior. This is at odds with all the others.

Here’s an IRAD paper:

Gilon D, Mehta RH, Oh JK, Januzzi JL, Bossone E, Cooper JV, et al. Characteristics and in-hospital outcomes of patients with cardiac tamponade complicating type A acute aortic dissection. Am. J. Cardiol. 2009 Apr. 1;103(7):1029–1031. PMID 19327436

From their data they say about 5% of type A dissections might have STEMI (no locations of course…). Though 10-15% have coronary artery involvement. Useful point here that comes up repeatedly in the IRAD data and elsewhere. In type A dissection, about 15% have coronary involvement and a third of those will have an MI (likely a STEMI)

Here’s a cohort with details of coronary involvement by the man who coined the classification system for dissected coronaries:

Neri E, Toscano T, Papalia U, Frati G, Massetti M, Capannini G, et al. Proximal aortic dissection with coronary malperfusion: presentation, management, and outcome. J. Thorac. Cardiovasc. Surg. 2001 Mar.;121(3):552–560. PMID 11241091

They found:

• Right Coronary Artery – 11
• Left Coronary Artery – 4
• Both – 9

This is pretty much the same study:

Kawahito K, Adachi H, Murata S-I, Yamaguchi A, Ino T. Coronary malperfusion due to type A aortic dissection: mechanism and surgical management. Ann. Thorac. Surg. 2003 Nov.;76(5):1471–6; discussion 1476. PMID 14602269

They found:

6% of their type As had coronary “malperfusion”; 9 of which where STEMIs.

• RCA – 8
• LCA – 2
• Both – 2

Here’s some case reports of anterior STEMI in type A dissection:

1. Vianna CB, Puig LB, Vieira ML, Shiozaki AA, Dauar D, Cesar LA. Spontaneous aortic dissection limited to sinus of Valsalva and involving the left main coronary artery. Int J Cardiovasc Imaging. 2007 Aug.;23(4):455–458. 

2. Funatsu T, Fukuda H, Takeuchi M, Masai M, Kawano S, Abe K. Progression of left coronary artery dissection during and after aortic replacement in acute type A aortic dissection: a case report. Ann Thorac Cardiovasc Surg. 2007 Jun.;13(3):209–212. 

3. Ohara Y, Hiasa Y, Hosokawa S. Successful treatment in a case of acute aortic dissection complicated with acute myocardial infarction due to occlusion of the left main coronary artery. J Invasive Cardiol. 2003 Nov.;15(11):660–662. 

4. Zegers ES, Gehlmann HR, Verheugt FWA. Acute myocardial infarction due to an acute type A aortic dissection involving the left main coronary artery. Neth Heart J. 2007;15(7-8):263–264. 

5. Camaro C, Wouters NTAE, Gin MTJ, Bosker HA. Acute myocardial infarction with cardiogenic shock in a patient with acute aortic dissection. Am J Emerg Med. 2009 Sep.;27(7):899.e3–6. 

6. Ravandi A, Penny WF. Percutaneous intervention of an acute left main coronary occlusion due to dissection of the aortic root. JACC Cardiovasc Interv. 2011 Jun.;4(6):713–715. 

7. Tominaga R, Tomita Y, Toshima Y, Nishimura Y, Kurisu K, Morita S, et al. Acute type A aortic dissection involving the left main trunk of the coronary artery–a report of two successful cases. Jpn. Circ. J. 1999 Sep.;63(9):722–724. 

Never mind that, i went straight to the master of the dissection – Rob Rogers. He tells me RCA STEMI is about 4-6 times as common as LCA STEMI in aortic dissection which fits nicely with the data above.

Bottom Line:

• If you see STEMI it’s likely a good old fashioned STEMI. Only about 0.1% of STEMIs are caused by dissection. [Hit the link for a great summary post on dissection]
• if it’s an anterior STEMI it’s even more unlikely to be an aortic dissection. But hey if it is a dissection, you can probably get it published as a case report…

PS I have just realised that i put the tweet out on April Fool’s day. Quite the coincidence.

UPDATE: as of Jan 2013 EMCrit has now done a nice podcast on Aortic Dissection which is compulsory listening.