New ORBITA data: Freedom from angina, stress echos improved with PCI

At EuroPCR in Paris, investigators of the controversial ORBITA trial presented two previously unreported benefits of percutaneous coronary intervention (PCI) for the study population.

For one, patients in the PCI group were about 20 percent more likely to report freedom from angina at six weeks of follow-up versus patients with stable ischemic heart disease who were randomized to the placebo arm. In addition, PCI was found to significantly improve a stress echocardiography score when compared to placebo, and the effect of PCI was stronger among patients with lower prerandomization measures of fractional flow reserve (FFR) and instantaneous wave-free ratio (iFR).

“The initial anatomic and hemodynamic effects of PCI were large,” wrote lead author Rasha Al-Lamee, MBBS, with Imperial College London, and colleagues. The new analysis was published May 22 in Circulation to coincide with the EuroPCR presentation.

“The resultant stress echo score was very clearly improved by PCI versus placebo; and the more severe the FFR and iFR, the larger the PCI effect on the stress echo score.”

The new analysis contained invasive physiology data from 196 patients—103 randomized to PCI and 93 randomized to a sham procedure. While FFR and iFR were found to interact with the stress echo test, there was no significant interaction with an angina frequency score or total exercise time on a treadmill.

But the difference between treatment arms in freedom from angina—49.5 percent for PCI and 31.5 percent for placebo—was particularly notable, the authors said. This contrasts with the Seattle Angina Questionnaire physical limitation and quality-of-life scores, which were not significantly different between groups. Also, as outlined in the original double-blinded study, PCI didn’t provide a substantial benefit in treadmill exercise time.

“The patient-centered symptomatic aim is ultimately to reduce angina and ideally render patients free from angina,” Al-Lamee et al. wrote. “Under blinded conditions, more patients directly reported freedom from angina with PCI than with placebo. It is possible that this end point detected an effect of PCI because it is easier to be sure that one is free of angina than to reliably distinguish different levels of pain.”

In an accompanying editorial, Ajay Kirtane, MD, said the six-week follow-up of ORBITA and the intensive medical therapy its patients received are important factors in interpreting the study.

“Symptomatic patients do not pursue therapies with a 6-week goal in mind,” wrote Kirtane, with Columbia University Medical Center and New York-Presbyterian Hospital. “For patients limited by their angina, the conventional alternative to coronary revascularization is a commitment to long-term therapy with multiple antianginal agents that may have side-effects and create issues relating to polypharmacy. For some patients this might be a reasonable choice, but for many patients it is not.”

Kirtane described it as “intuitive” that PCI would be found to have the strongest benefit over placebo in patients with more restricted blood flow. He added it is important for clinicians to contextualize the results of new trials in relation to previous research, rather than rush to judgement and either totally accept or dismiss the findings—which he believes many did with ORBITA.

“Responsible and thoughtful caregivers recognize both the strengths and limitations of new evidence-based medicine but are humble enough to dynamically adapt their approach as new evidence (and new patients) come along,” Kirtane wrote. “Within that more nuanced rubric, the ORBITA trial teaches important lessons that will ultimately transcend all controversies.”