Question 18

College answer

Pros 
a.    In the presence of ST elevation post OHCA (Out of Hospital Cardiac Arrest) all patients without absolute contra-indications should go to cath lab 
b.    Patients without clear symptoms or signs of ischaemia may still have had an ischaemic cause for arrest. Case series and registries of OHCA have suggested that 1/4 cases taken to cab lab with no ECG evidence of ischemia will have lesions requiring treatment. Treatment in these patients will lead to a 60% survival improvement with a 90% chance of good neurological recovery. Most studies have published a number needed to treat of 4 to prevent one death with a 90% chance of good neurological recovery. 
c.    Current recommendations from the American Heart Association suggest that any OHCA with 
ROSC should go to cath lab if ischemia is suspected 
d.    Transfer to cath lab with treatment may prevent further cardiac arrests 
e.    Professional (American Heart Association and European Resuscitation council) bodies who have made recommendations say there is no role in waiting to assess neurological recovery 

Cons 
a.    These may be unstable patients  
b.    The cath lab maybe isolated from other emergency services and take staff away from ED or ICU 
c.    Transfer to another centre may be required 
d.    Experienced staff are required to anaesthetize a patient undergoing coronary angioplasty or stenting. 
e.    Taking all comers to cath lab may lead to many poor outcomes due to high pre OHCA morbidities. 
f.    Many patients may be taken after prolonged cardiac arrest who may go onto survive with poor neurological recovery 
g.    There are financial consequences to running a 24-hour cath lab service 
h.    If there is another explanation for the cardiac arrest the time in the catheter lab maybe detrimental to the patient 
i.    Anti-coagulation and anti-platelet medications may increase the risk of haemorrhage  
j.    Difficulty with targeted temperature management in cath lab environment 
 
Examiner Comments: 
 
Overall reasonable answers. Not a great deal of reference to guidelines, and the “pro” side was not as well answered as the “con”. 
 

Discussion

The excellent powerpoint presentation by Georg Furnau Luebeck for the European Society of Cardiology is a good starting point to look for references. Some of the best review of the most important arguments for and against angiography in unselected cardiac arrest patients can be found in the paper on the study design of the COACT trial by Lemkes et al (2016).

Pros:

• 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

• 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 
• 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
• TOMAHAWK trial (Desch et al, 2021) did not find any benefit if the patient was haemodynamically or electrically stable.