Question 8

College answer

Not available.

Discussion

This question is essentially the same as Question 18 from the first paper of 2018, except that this time the examiners asked for "advantages and disadvantages" instead of "pros and cons".  Sensitive readers may find themselves awake at night, wondering what sort of hidden meaning might be lurking in these seemingly random changes. On one hand, this certainly does not look like a deliberate creative decision; on the other hand, surely every inch of this exam paper must be lovingly crafted by experts in medical education? To believe otherwise would be to go mad. Before the reader loses all hope, here are the advantages and disadvantages of urgent post-cardiac-arrest angiography:

Pros Advantages:

• Angiography for all would pick up coronary artery disease which would otherwise be missed:
  • ST changes in the ECG post arrest are difficult to interpret 
  • History of chest pain may not be available
  • There is often coronary disease without ECG changes: of the patients who had no ECG changes, Hollenbeck et al (2014) found an acute thrombotic coronary occlusion in 26%.
• To exclude coronary artery disease is an important step in the process of determining the causes of the cardiac arrest
• Patients undergoing angiography receive a "greater intensity of care" (Lemkes et al, 2016) - they are resuscitated more aggressively, get seen by more doctors, receive early anticoagulation and have more mechanical / pharmacological support, which could translate into better outcomes.
• Multiple studies have demonstrated improved outcomes in patients who had no ST changes and who ended up having a PCI for a clinically significant stenosis (Spaulding et al, 1997; Dumas et al, 2010)
• There is society support for this practice (AHA/ACC, ESC/ERC)

Cons Disadvantages:

• Cardiac arrest is not uniformly a phenomenon of coronary artery disease, i.e. there are many noncardiac causes, of which several (eg. SAH) would surely not benefit from the obligatory loading doses of dual antiplatelets. This is an argument against immediately rushing to the cath lab.
• Angiography may exacerbate the acute kidney injury which often accompanies the post-resuscitation syndrome, mainly by means of a contrast load.
• Even where there is coronary artery disease, not all patients can be stented, and the survival benefit of angiography seems to be limited to those patients in whom stenting was successful. In about 25% of patients undergoing PCI, there is either no lesion or a non-stentable lesion, even when there are ST changes (and if there aren't, that proportion rises to 75%) according to Dumas et al (2010)
• Even where there is stentable disease, there may be no mortality benefit to stenting it, because outcome depends more on the global ischaemic damage from "down-time" than the events in local coronary territories. SWEDEHEART study (Wester et al, 2018) certainly did not find any mortality difference between patients who had early PCI versus those who did not, even though 43% of the patients were found to have 90% stenosis in one of their vessels.
• If stenting is so good for outcomes, then stenting all the lesions should give maximal benefit - but in fact it seems the fewer stents you do, the better. The CULPRIT-SHOCK trial (Thiele et al, 2017) found improvement in mortality if the angiographer limited their post-arrest intervention to just the culprit lesion, with both mortality and risk of AKI
• Even when there is coronary artery disease, and where you end up stenting it immediately, there does not appear to be a substantial survival benefit. The COACT trial from the Netherlands (Lemkes et al, 2019) found that immediate angiography following cardiac arrest without ST elevation did not improve survival at 90 days. Unlike the PROCAT registry, only 20% of the COACT patients had an acute coronary lesion (33% in the "immediate angiography" group).   

What's happened since the last time this appeared in 2018?

• Jentzer et al published a trial in (2018), specifically in February of 2018 (i.e. long after the examiners would have stopped thinking about this question paper, but before was inflicted on the trainees in March). Survival was much better in the angio group (56.2% vs 31%) as was the neurological outcome (28% vs 11%). However, 
• Verma (2020) performed a meta-analysis of about 3500 patients, and found little difference in mortality or outcome; rather, the 30-day mortality was more related to the presentation comorbidities 
• The TOMAHAWK trial (Desch et al, 2021) looked at a cohort of 554 patients and also did not find any mortality benefit at 30 days.
• Song et al (2021) used the GRACE risk score and found that patients with a high score (i.e. old age, history of CCf or MI, tachycardia or hypotensive, with ST-segment depression, AKI, raise cardiac enzymes) seem to have some survival benefit from early angiography.