I posted the following comments for SERMO, a social network for over 300,000 physicians yesterday.. I would encourage any physician readers to join SERMO and engage in the medical discussions going on there.
As physicians, we have to decide on a daily basis how to evaluate the patient who has chest pain. Most chest pain is not cardiac, but if we miss the patient whose chest pain is a sign of coronary ischemia or impending infarct, the results can be catastrophic.
The standard approach across the US for patients presenting with stable chest pain is to do some sort of stress test. Usually, treadmill or chemical ECG stress tests are combined with an associated imaging technique (nuclear or echocardiography). These kinds of tests are considered “functional” or “physiologic.”
Coronary CT angiography (CTA), on the other hand, is a visualization of the actual anatomy of the coronary arteries, and has been proposed by many as a more useful starting point for evaluation of chest pain.
Prior to this study, there were no randomized comparisons of these two approaches on health outcomes in patients with stable chest pain. In patients with acute chest pain, presenting to the ER, two randomized controlled trials have shown superiority of CT angiography.
This morning at the American College of Cardiology meetings in San Diego, the results of the PROMISE (the PROspective Multicenter Imaging Study for Evaluation of Chest Pain) were presented. Simultaneously with the presentation, the full paper was published here.
As a noninvasive cardiologist board-certified in both echocardiography and nuclear cardiology, and as a reader of coronary CT angiography, I was particularly interested in hearing and reading these results.
The study was a well-done, realistic comparison of these two techniques. Over ten thousand patients presenting with stable chest pain were randomized to CTA versus stress testing at multiple different sites.
The composite primary end point was death, myocardial infarction, hospitalization for unstable angina, or major procedural complication. Secondary end points included invasive cardiac catheterization that did not show obstructive CAD and radiation exposure.
All tests were interpreted locally and the site clinical team made all subsequent care decisions. Stress MPI (nuclear) were ordered in 67%, stress echo in 23% and stress ECG in 10%. Pharmacologic stress was utiilized in 29%. The median follow up was 25 months.
The major finding was that there was no difference in occurrence of the primary end-point between the anatomic strategy (CTA, 3.0% at 25 months) and the functional strategy (stress testing, 3.3%).
My Take Home Points From the PROMISE Study
1. In the stable chest pain patient (even with significant risk factors) the prognosis is good.
2. We now have two roughly equivalent options for evaluating such patients, CTA or stress testing.
3. CTA is less likely to result in a cath with totally normal coronary arteries and it is useful for identifying early atherosclerosis. The patients in the CTA arm received more statins and aspirin due to this.
4. Currently, there are insurance companies which will not approve CTA for any indication other than congenital coronary artery anomaly. It is highly likely that this study will move CTA from a IIA indication to a I indication in guidelines and allow wider acceptance by insurance companies.