Helping patients by changing my habits: Observations from the DISCHARGE Trial

June 16, 2022

A habit cannot be tossed out the window; it must be coaxed down the stairs a step at a time.

Mark Twain


Each time we meet with a patient to discuss known or suspected heart disease, a conversation about their daily habits ensues. Do they walk regularly? What does their usual diet include? Smoking, stress, and sleep are all topics of interest as we work to better understand how their choices might be impacting their heart health.

But rarely are the tables turned in such a way that the patient begins asking how the clinician’s regular choices might impact the patient’s heart health. We might discuss the pros and cons of a treatment option, but do we consider how our “clinical habits” might actually be increasing a patient’s risk?

The DISCHARGE Trial, published in the New England Journal of Medicine, forcefully makes the case that our “clinical habits” do indeed impact a patient’s overall risk, meaning that we need to carefully assess our own habits as we assess those of our patients.

The clinical team leading the DISCHARGE Trial randomized over 3,500 patients with stable chest pain and intermediate-to-high probability of obstructive coronary artery disease (CAD) who had been referred to the cath lab for invasive coronary angiography (ICA). Like many of the most perplexing cardiology cases, the majority of these patients had continuing symptoms that were unimproved by medication or had stress tests that were nondiagnostic.

At this point, with patients on their way to the cath lab, each was randomized between either usual care (continue on to ICA) or a coronary CT angiogram (CTA).

3.5 years of subsequent follow-up revealed several important findings about those patients sent for coronary CTA in lieu of the cath lab:

  • Unnecessary procedures were avoided: >75% reduction in diagnostic ICAs
  • Complications were reduced: >70% reduction in procedure related complications
  • Cath lab efficiency increased: >3x increase in the PCI:ICA ratio as the majority of patients sent for ICA post-CTA underwent revascularization
  • Safety was maintained: Major adverse clinical events (MACE) were fewer in the CTA arm, but the difference did not reach statistical significance.

These data invite all cardiologists to ask “Do my habits put patients at risk?” Do our common clinical choices, which we have learned to make through hard-earned experiences in training and clinical practice, potentially expose our patients to risks that could be reduced if we were to step back and reassess why we do what we do?

For example, a wonderfully thoughtful cardiologist recently explained to me that while he has shifted his patients toward a CTA+FFRCT pathway to better inform his clinical decision making, some of his partners have not adopted a CTA-driven pathway. These partners consistently refer to ICA those patients who are unresponsive to medical therapy or have nondiagnostic or indeterminate stress tests.

There is no question that these cardiologists are working to care responsibly for their patients by using a tool that has been a standard for years. However, there is a question as to whether the use of diagnostic ICA for these patients in whom CAD has not been anatomically identified by CTA is worth the nearly 4x increase in procedural complications and the startlingly high rates of finding no obstructive CAD.

On the heels of the new ACC/AHA Chest Pain Guidelines, many clinicians are reconsidering how they evaluate and diagnose chest pain. As we assess our clinical habits, we create an opportunity to change patterns, one patient at a time. The DISCHARGE Trial clearly demonstrates that a small adjustment, in this case the expanded use of coronary CTA to better identify CAD, delivers significant, lasting benefits to many of our patients.

— A perspective from HeartFlow Chief Medical Officer, Campbell Rogers, MD
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