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PHILADELPHIA -- The symptoms of stable angina can be eased by percutaneous coronary intervention (PCI) alone in the absence of antianginal medications, the randomized ORBITA-2 trial showed.

Compared with a sham control, such angioplasty improved a trial-specific angina symptom score at 12 weeks (2.9 vs 5.6 points, OR 2.21, 95% CI 1.41-3.47), reported Rasha Al-Lamee, MBBS, PhD, of Imperial College Healthcare NHS Trust in London, who explained PCI's change in scores as indicating:

• Fewer angina episodes of angina (an immediate change after the procedure)
• No difference in doses of antianginal medications
• No difference in clinical events (acute coronary syndromes having occurred in four vs six patients)

Benefits of PCI were also suggested by the secondary endpoints of the Canadian Cardiovascular Society angina score (OR 3.76, 95% CI 2.43-5.82) and modified Bruce treadmill exercise time (59.5 seconds better than placebo, P=0.008), Al-Lamee reported at the American Heart Association (AHA) annual meeting. Findings were simultaneously published in the .

ORBITA-2 is the first placebo-controlled trial to show efficacy in angina relief for PCI, supporting the choice of either antianginal medication or PCI as the upfront strategy for patients with stable angina.

"ORBITA-2 proves that PCI relieves angina in symptomatic patients with chronic coronary disease and is safe. Results align with our understanding of the biology and pathophysiology of angina," said session discussant Connie Hess, MD, of UCHealth Heart and Vascular Center-Anschutz in Aurora, Colorado.

Multivessel Disease

The trial thus seems to refute the original ORBITA trial, which was the first sham-controlled trial of PCI in people on maximally tolerated antianginals. At 6 weeks after having been randomized to the intervention or a sham procedure, patients had shown similar improvements in exercise time in both groups.

However, unlike that older trial, ORBITA-2 allowed multivessel disease, mandated that all participants have ischemia, and had them refrain from antianginal therapy during the study.

Hess concluded that PCI is unlikely to make ORBITA-like patients feel better, namely those with minimal symptoms tolerating antianginal therapies. On the other hand, PCI can improve health status for those more akin to the ORBITA-2 cohort unable to take these medications.

For stable coronary artery disease (CAD), guidelines currently recommend revascularization as an add-on therapy for symptom relief for angina refractory to maximal medical therapy. However, in the real world, up to half of all elective catheterizations are performed on people on zero or just one antianginal.

"Of course, the two approaches both have their own pros and their own cons, their own costs and their own limitations. There will be patients who prefer an upfront procedure and are prepared to take on that long-term risk of potential procedural complication in the attempt to have less antianginal medication burden, and there will be other patients who will tolerate two to three antianginal medications at full dose and are happy to persist and adhere with that high-dose strategy," Al-Lamee said during an AHA press conference.

However, 59% of ORBITA-2 participants in both arms still had residual symptoms, she pointed out.

"What's most important ... is to try and work out before we offer them the options, which patients will benefit most from which strategy, and before we put in a stent, which patients may benefit the most from that stent. And that's actually what we hope to do with further secondary analysis and actually with a combined dataset within the two trials," Al-Lamee said.

"The mechanism of residual angina after a successful PCI is curious and needs to be explored," agreed AHA panelist Martin Leon, MD, of Columbia University/NewYork-Presbyterian Hospital in New York City. "Whether there are responder subgroups would help you understand who might receive first PCI versus medical therapy at higher doses ... The goal of course, is to have an angina-free outcome."

In any case, Leon said that ORBITA-2 challenges some of the current CAD guidelines.

"My surgical colleagues have asked me for many decades whether or not PCI actually works. And now I can say with confidence, with a placebo-controlled trial, that PCI certainly does have an impact on patients with documented angina, severe coronary stenosis, and demonstrated ischemia, which to me is extremely important," he said.

Study Details

For ORBITA-2, Al-Lamee and colleagues had 301 people randomized (mean age 64, 79% men) to PCI or sham. This was a group in which 80% had ischemia in one cardiac territory, 17% in two, and 2% in three territories.

Before randomization, the trialists had candidate patients stop their antianginal medications, record their symptoms for 2 weeks using a smartphone app, and undergo assessments including an exercise treadmill test and dobutamine stress echocardiography.

Then, at the randomization visit, a research angiogram was performed, followed by pressure wire studies. In the target vessels, the median fractional flow reserve was 0.63, and the median instantaneous wave-free ratio was 0.78. That was the point that individuals were randomized to PCI or placebo. Operators were instructed to revascularize all ischemic vessels in the PCI arm during the index procedure. Placebo patients were sedated for a minimum of 15 minutes without any intervention having taken place.

Discharged with dual antiplatelet therapy, participants then underwent follow-up in which they continued to record their angina every day on the smartphone app; antianginal medications could be restarted as necessary. In-clinic tests were repeated at the final visit at 12 weeks.

One limitation of the trial, Hess cautioned, was that the ORBITA-2 angina symptom score is not validated.

Also notable is the potential for exclusion bias in the trial, given that the investigators had started out with over 900 candidates for screening, Leon added.

Nevertheless, ORBITA-2 strengthens the case for angioplasty in some patients with stable CAD.

"Most of us already would refer patients for PCI who were symptomatic ... And this just shows that it really does have a significant impact," said AHA press conference panelist Christine Albert, MD, MPH, of Cedars-Sinai Medical Center in Los Angeles. "And it's not necessarily just the placebo effect of having undergone surgery, which has always been the question of any of these interventional procedures."