Some notes on mechanical complications of MI

Ng R, Yeghiazarians Y. Post Myocardial Infarction Cardiogenic Shock: A Review of Current Therapies. J Intensive Care Med. 2011 Jul. 11. Ahead of Print

[youtube http://www.youtube.com/watch?v=zY4WZdxwFf0&w=640&h=390]

Found this via R&R in the fast lane. Here’s a few notes and thoughts:

• the bit on severe LV dysfunction isn’t as interesting because nothing really works here apart from reperfusion
• the bits on complications of MI resulting in cardiogenic shock is much more interesting
• Uses the big SHOCK registry for a lot of the data

ACUTE MITRAL VALVE RUPTURE
[youtube=http://www.youtube.com/watch?v=JjqmWDEjGuo&w=640&h=360]

• Acute MR and rupture in 8% of cardiogenic shock so really well worth looking for it seems; median time to rupture of 13 hrs
• RCA infarcts with right dominant circulation the biggest risk as the PDA supplies valve. In a left dominant it’s supplied by two vessels
• suggest SNP as a vasodilator to reduce afterload and keep forwards flow but of course not great when BP is low

VENTRIUCLAR SEPTAL RUPTURE

• VSR occurs about 15 hrs post MI, not as late as we used to think
• 5% of cardioggenic shock
• usually LAD lesions
• left to right shunt is the physiology
• vasodilators might reduce shunt
• IABP often needed
• 80% mortality at 4 weeks – WOW

VENTRICULAR FREE WALL RUPTURE
[youtube=http://www.youtube.com/watch?v=DPHsztboH3w&w=640&h=360]

• 50% within first 5 days; 90% within 2 weeks
• 2% of cardiogenic shock
• 4 week mortality of 55% (given the mechanism I suspect it might be much higher than that!)
• suggest that first MI and single vessel MI more at risk because of lack of collateral supply
• lateral and post wall probably more at risk but due to their infrequency anterior (from LAD) is much more commonly seen in reality
• most die immediately; those who survive have smaller ruptures which have plugged off
• surgical repair the only option

Here’s a great talk from Stuart Swadron on valvular emergencies at All LA conference