Debate: “Should all coronary angiograms be done by interventionists?”

April 6, 2017 Posted by Dr. Duncan Hogg no Comment

This is not a new debate I know, but further persuasive data on the use of pressure wires made me revisit the thought that diagnostic coronary angiograms should optimally only be done by interventionists; I would be interested to hear your views.

For many years now we have known that an intra-coronary lumenogram often doesn’t give us the information we need to optimally look after our patients. Pressure wire and IVUS has proven that obstructive coronary disease may not be definable by pictures alone.

At last month’s ACC DEFINE-FLAIR and iFR-SWEDEHEART further reinforced the use of pressure wires at the time of invasive angiography, and demonstrated that iFR can reduce time and patient discomfort compared to FFR, by not needing the use of iv adenosine. 

We were early enthusiasts of pressure wire and haven’t had cath-only doctors in our institution for quite a while now. So recently, with a visiting mobile lab, where we were unable to do anything beyond a plain angiogram, unusually we had a number of patients we felt didn’t receive optimal decision-making completed on the day.

Is that such a bad thing? Patients who didn’t have clearly obstructive disease, but with moderate plaques and continuing symptoms despite medical therapy, could return for a pressure wire directed PCI. If the pressure wire is negative, that of course is prognostically reassuring, but they’ve had an unnecessary second visit and procedure, which is unproductive for them and us.

It appears the use of FFR remains low at the time of invasive angiography. As we discussed last week, that could be because our selection process isn’t strong enough regarding patients who should come to the cath lab. But if a lot of angiography is being done by non-interventionists, there may not be the knowledge nor available skills to offer it. 

Most interventionist argue that the power of the invasive angiogram is to offer the fullest diagnostic assessment in one sitting and to be able to proceed to PCI on the day if appropriate as well as discuss objectively appropriate surgical revascularisation. Surely gone are the days when it’s said ” if you are in there anyway put a vein graft beyond that moderate disease”; I think surgeons have largely moved away from this subjective approach, and these days, I find I’m more regularly asked if disease is pressure wire positive.    

Is it acceptable if the cath-only doctors have instant access to an interventionist to take over if further action is needed? It may be a slightly clumsy system, but it can work. My experience in Canada was that on-call interventional fellows were almost always available to step in at the request of the cath-only doctors. That said, there was quite a bit of variability with this approach, which was centred more on how many cases the cathing doctor was doing in the session, rather than the individual patient’s need. 

Reminiscing further, I often helped out cath-only doctors by offering and doing radials when there were femoral access problems, and more worryingly dealing with iatrogenic problems, including a coronary dissection, sheath-related thrombo-embolism, and more.

We recognise that an invasive angiogram is increasingly safe, and an experienced operator can take less than 10 minutes to conduct a simple diagnostic study. But a clear advantage for having only interventionists doing them is that they would have a complete skill-set to do all-comers,  and can address the small but recognised potential complications of the procedure, if and when they occur, and without delay.   

In Canada in 2007, so before FAME was published, pressure wires weren’t reimbursed in addition to the diagnostic angiogram. This lack of reimbursement and the additional cost of adenosine, particularly when given iv, certainly limited their use.  

But in this contemporary age, with the strong FFR evidence-base and now with the most recent iFR data, it should really make pressure wires almost ubiquitous for the evaluation of both stable and acute chest pain patients.

I hear the howls go up from some non-invasive colleagues! “A manifesto for getting more interventionists, surely you have enough of them with the evolution of more sustainable primary PCI rotas? We need to get more simple angiograms done, and we need more sub-specialists in other areas too.”

Indeed, training a fully competent coronary interventionist takes far longer than training someone to do the majority of simple angiograms. But, we should have less simple angiograms coming to the cath lab, and it isn’t about the workforce, it is about the best job for the patient, with a fully diagnostic evaluation on the first sitting, with minimal risk, and using the least time and overall resource.

So to rephrase the debates starting point: “Why shouldn’t coronary angiography only be done my coronary interventionists?”.

This Blog is Posted by Dr. Duncan Hogg

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