Sue Ieraci: Invasive dangers

THERE has long been a rivalry in medicine between the “thinkers” and the “doers” — cognitive versus procedural skills.

In the 1990s, the federal government’s Relative Value Study examined the relative work value of various Medicare Benefits Schedule items, particularly comparing procedural and consultative items. The review is widely regarded as having gone nowhere, but it did provide some very interesting data.

What happens, though, when a predominantly cognitive specialty becomes procedural?

Cardiology has essentially been a cognitive specialty, other than pacing, EPS (intracardiac electrophysiology study) and angiography. The physician cardiologist acted as gatekeeper to the cardiac surgeon, motivated to maximise medical therapy in coronary disease prior to referring for grafting.

However, the advent of percutaneous coronary stenting, which has become increasingly common since the 1990s, has seen more and more cardiologists cross to “the other side”. Is this a good thing?

There are two questions here. First, does the general medical community have a clear picture of the appropriate place for stenting? Second, have we lost something valuable by removing the barrier between the physician and the intervention?

We have moved from the days of administering thrombolysis in patients with a clear diagnosis of transmural acute myocardial infarction (AMI) to the era of the high sensitivity troponin, detecting cardiomyocyte ischaemia, not necessarily coronary thrombosis. If the so-called NSTEMI (non-ST elevation myocardial infarction) patient goes to the cardiac catheter lab, what will happen, and what are the costs and benefits?

A Cochrane review looked at early invasive vs conservative strategies in the management of acute coronary syndrome and NSTEMI.

Five trials, totalling 7818 patients, compared patients randomly assigned either to undergo immediate invasive management with coronary catheterisation and stent placement (as necessary) or to be treated with medications and no immediate invasive strategy.

The review authors concluded that an invasive strategy was associated with reduced rates of refractory angina and rehospitalisation in the shorter term and myocardial infarction in the longer term. However, they did find that the invasive strategy was associated with a doubled risk of procedure-related heart attack and increased risk of bleeding and procedural biomarker leaks.

When expressing the results as number-needed-to-treat, they found that no deaths were prevented by the invasive strategy, one in 50 avoided a heart attack in the following year, but one in 33 suffered a procedural heart attack, and one in 33 had a major bleeding event.

In a similar meta-analysis, using American data, researchers found no benefit at all from angiography and stenting for NSTEMI or stable acute coronary syndrome, but 2% procedural complications.

The vast majority of people admitted to hospital with chest pain have stable acute coronary syndrome, NSTEMI or non-cardiac pain. Only a small percentage have transmural AMI.

Are these patients best served by being admitted under an interventional cardiologist, with an interest in doing a procedure, or should physician-cardiologists optimise medical therapy and only refer the failed patients for procedures?

Do interventional cardiologists have enough incentive to maximise medical therapy in the patients under their care?

Dr Sue Ieraci is a specialist emergency physician with 30 years’ experience in the public hospital system. Her particular interests include policy development and health system design, and she has held roles in medical regulation and management.

Posted 15 April 2013