AT TCT 2017
DENVER (FRONTLINE MEDICAL NEWS) – The first-ever blinded, sham-controlled randomized trial of percutaneous coronary intervention for stable angina failed to show a significant improvement in exercise time for PCI, compared with placebo PCI, Rasha Al-Lamee, MD, reported at the Transcatheter Cardiovascular Therapeutics annual educational meeting.
The blockbuster results of the ORBITA trial, published online in the Lancet simultaneously with Dr. Al-Lamee’s presentation in Denver, quickly went viral, with a story splashed across the front page of the New York Times under the headline “ ‘Unbelievable’: Heart Stents Fail to Ease Chest Pain .” Interventional cardiology thought leaders at TCT said the newspaper piece, and a Lancet editorial commentary entitled “Last nail in the coffin for PCI in stable angina?” that accompanied publication of ORBITA, failed to convey the study’s major limitations, drawbacks that Dr. Al-Lamee readily acknowledged.
“This was a very restricted patient population. They had single-vessel disease, and the baseline data showed these patients had very good exercise capacity, they had about-monthly angina – not daily, but monthly – they were being treated with intensive medical therapy that would not easily be replicated in the real world, and they had very little ischemia. This means that, regardless of what you did to the coronary artery, there was going to be very little you could demonstrate from the standpoint of clinical therapeutic benefit,” commented Martin B. Leon, MD , professor of medicine at Columbia University and director of the Center for Interventional Vascular Therapy at New York-Presbyterian/Columbia University Medical Center.
“The fact that PCI didn’t meet the primary endpoint in this population doesn’t really disturb me. The concern here is that the results become distorted and sensationalized and extrapolated to other patient populations,” he cautioned.
What ORBITA did
ORBITA (Objective Randomized Blinded Investigation with Optimal Medical Therapy of Angioplasty in Stable Angina) included 200 patients referred to five U.K. cardiac catheterization labs for diagnostic angiography. Participants had to have stable angina, single-vessel disease, and at least one 70% or greater stenosis; in fact, their stenotic severity averaged 84.4% by quantitative coronary angiography.
The patients received 6 weeks of intensive medical therapy during which they were uptitrated to an average of three antianginal medications. They then underwent either real or sham PCI followed by 6 weeks of recovery, during which both the patients and care team remained blinded. Then the same assessments done before randomization were repeated, including exercise treadmill testing, the Seattle Angina Questionnaire, and dobutamine stress echocardiography, explained Dr. Al-Lamee of Imperial College London.
The primary outcome was achievement of at least a 30-second greater improvement in total exercise time following PCI, compared with sham PCI, an effect size chosen based on placebo-controlled studies of antianginal drugs. The PCI group improved by a mean of 28.4 seconds, the controls by 11.8 seconds, and the resultant 16.6-second difference made for a negative result (Lancet. 2017 Nov 2; doi: 10.1016/S0140-673632714-9 ).
PCI did, however, result in significant improvement in the secondary endpoint of ischemia reduction as assessed by blinded evaluation of dobutamine stress echocardiography results. The PCI group’s mean peak stress wall motion index score improved from 1.11 prerandomization to 1.03 – that is, normal – at follow-up 6 weeks post procedure while remaining unchanged in the sham PCI group, Dr. Al-Lamee noted at the meeting, sponsored by the Cardiovascular Research Foundation.
What the results mean
Dr. Al-Lamee said the ORBITA results should enable cardiologists to sit with patients similar to those in the trial and have a more informed, patient-centered discussion in which intensive medical management can be offered as an initial first-line option with an understanding that it will likely improve their symptoms to the same degree as angioplasty.
“There will be those patients who would rather avoid having to take high doses of antianginal medications with the side effects they involve, who may well prefer to have an upfront procedure with a small risk in order to reduce their pill count, and who also would rather have improved blood flow to the heart, which may have prognostic implications,” Dr. Al-Lamee said.
Carl L. Tommaso, MD , part of the panel of discussants at the late-breaking clinical trials session in which Dr. Al-Lamee presented the ORBITA findings, applauded the investigators for their ingenious study design, which included elaborate blinding techniques involving music played through headphones throughout the procedure, heavy sedation, separate angioplasty and clinical care teams, the same postprocedural instructions and discharge letter, and dual-antiplatelet therapy in both study arms.
“This is a great study. I don’t think any of us could get this study past an institutional review board in the United States,” commented Dr. Tommaso, director of the cardiac catheterization laboratory at Skokie (Ill.) Hospital.
He added, however, that he wouldn’t have performed PCI on the basis of angiographic findings alone in stable angina patients with a 9-minute treadmill exercise time.
Where OPTIMA fell short
Gregg W. Stone, MD , who moderated the session, said a big problem with the study was that, even though all subjects had angiographically severe stenoses, it has been clear for years that angiography alone is inadequate to identify clinically significant coronary lesions. It’s imperative to also show physiologic evidence of clinically important impairment of blood flow before intervening. Yet 29% of subjects had a preprocedural fractional flow reserve (FFR) measurement greater than 0.80 in their stenotic vessel, which indicates normal blood flow.
Angiography vs. functional testing
“Twenty-nine percent of patients, we’d all agree, should not have had angioplasty because they had no ischemia,” said Dr. Stone, professor of medicine at Columbia University, New York, and director of the TCT conference.
All subjects in ORBITA did indeed undergo measurement of both FFR and instant Wave-Free Ratio (iFR) while on the table immediately before and after their real or sham PCI. The mean stenosis severity was 0.69 by FFR and 0.76 by iFR, readings indicative of significantly impaired flow. However, the operators were blinded as to those results. The rationale for withholding that information was that, even though it has been shown to be clinically useful, studies show that 80% of angioplasties are done based upon angiography alone, and the ORBITA investigators wanted the study to reflect routine clinical practice, Dr. Al-Lamee explained.
“I think one of the many lessons coming out of this trial is to see the discrepancy between the angiogram and functional testing. We cannot guide our therapy solely by the angiogram. We have to get physiologic data and consider that together with symptoms in the patient’s clinical context,” said panelist Allen Jeremias, MD , director of interventional cardiology research at St. Francis Hospital in Rosyln, N.Y.
Commentary goes too far
The “last-nail-in-the-coffin” Lancet commentary (2017 Nov 2. doi: 10.1016/S0140-673632757-5 ) penned by David L. Brown, MD, of Washington University in St. Louis and Rita F. Redberg, MD, of the University of California, San Francisco, emphatically declared that the ORBITA results mean all cardiology guidelines should be revised to downgrade the recommendation for PCI in patients with angina despite medical therapy. Dr. Al-Lamee was one of many at TCT 2017 who took strong exception to that.
“This is the first trial of its kind. I think it would be very easy to take the results of this trial and overextrapolate. To downgrade the guideline recommendations based on this study would be an incredibly large overreach,” she said.
Ajay J. Kirtane, MD , who chaired a press conference in which Dr. Al-Lamee presented the ORBITA results, had a further criticism of the editorial.
“Some of the risks of PCI as described in the editorial are just factually inaccurate. An MI rate of 15%, an acute kidney injury rate of 13% – those are simply factually incorrect,” said Dr. Kirtane, director of the cardiac catheterization laboratories at New York-Presbyterian/Columbia University Medical Center.
The ORBITA trial was sponsored by Imperial College London and funded by grants from the National Institute of Health Research Imperial Biomedical Research Center and charity organizations. Dr. Al-Lamee reported serving as a paid consultant to Philips Volcano, which supplied the coronary pressure wires for physiologic testing.