Heart Attack and Stroke: Same Disease, Different Organs?

John Chen, MD

I’m spending the last month of internal medicine residency on a neurology rotation.  I suppose that’s fair; my wife, a neurology resident, had to do a whole year of medicine.  To me, the most interesting part of neurology is the parallel between stroke and acute myocardial infarction (AMI).  Conceptually these are two manifestations of a common underlying disease process.  Yet, there are glaring differences in their management, and I can’t help but wonder why.

For instance, neurologists and cardiologists use different protocols for anticoagulation and thrombolysis.  Tissue plasminogen activator (tPA) is a first line therapy for ischemic stroke unless there are contraindications, including recent use of anticoagulation.  Thrombolytic therapy is also used to treat STEMI when percutaneous coronary intervention (PCI) is not immediately available.  In contrast to stroke, STEMI thrombolysis calls for higher doses of tPA as well as concurrent infusion of heparin to prevent recurrent thrombosis.1  Perhaps thrombolysis after stroke is a more cautious affair due to the risk of reperfusion injury and hemorrhagic conversion.

For decades STEMI PCI has largely replaced tPA, yet endovascular therapy for stroke is a relatively recent innovation and its utility is limited to proximal large vessel occlusions.  While PCI relies on balloon expandable stents designed to prevent restenosis, stenting is perhaps a less attractive option in stroke due to the tortuous anatomy of intracranial vessels and the bleeding risk associated with dual antiplatelet therapy.2 Instead, neurologists perform mechanical thrombectomy using stent retrievers and aspiration catheters.  While routine thrombectomy during STEMI PCI is generally not beneficial,3 aspiration and rheolytic catheters can be used selectively in the event of large thrombus burden.

Finally, evidence does not support facilitated PCI (i.e. pretreatment with tPA prior to PCI).4-5  Interestingly, it is common practice among neurologists to pretreat with tPA prior to mechanical thrombectomy.  Theoretically pretreatment may facilitate clot extraction, but does this strategy outweigh the additional bleeding risk?6

Heart attack and stroke are similar diseases occurring in different organs.  With widespread adoption of mechanical thrombectomy for acute stroke, the fields of neurology and cardiology increasingly share similar practices.  Still, there are striking differences in stroke and AMI management—no doubt a constant source of cognitive dissonance as I complete my neurology rotation and start cardiology fellowship.

 

References:

  1. Kijpaisalratana N, Chutinet A, Suwanwela N. Hyperacute simultaneous cardiocerebral infarction: Rescuing the brain or the heart first? Frontiers in Neurology 2017;8:664.
  2. Gralla J, Brekenfeld C, Mordasini P, Schroth G. Mechanical thrombolysis and stenting in acute ischemic stroke. Stroke 2012;43:280-285.
  3. Jolly SS, James S, Dzavik V, et al. Thrombus aspiration in ST-segment elevation myocardial infarction. An Individual Patient Meta-Analysis: Thrombectomy Trialists Collaboration. Circulation. 2016;135:143–152.
  4. The ASSENT-4 PCI Investigators. Primary versus tenecteplase-facilitated percutaneous coronary intervention in patients with ST-segment elevation acute myocardial infarction (ASSENT-4 PCI). Lancet. 2006;367:569–578.
  5. Ellis SG, Tendera M, de Belder MA, et al. Facilitated PCI in patients with ST-elevation myocardial infarction. N Engl J Med. 2008;358:2205–17.
  6. Kasemacher J, Mordasini P, Arnold M, et al. Direct mechanical thrombectomy in tPA-ineligible and -eligible patients versus the bridging approach: a meta-analysis. J Neurointerv Surg. 2019;11:20-27.