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Procedure clarifies diagnosis, allowing better treatment, QOL for angina patients with ‘negative’ angiogram
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SAN DIEGO — An interventional diagnostic procedure for patients with angina and without obstructive CAD was safe, feasible and led to a change in physician diagnosis in nearly half of patients, according to data from the CorMicA trial presented at TCT 2018.
“Stratified treatment guided by the results of this invasive diagnostic procedure improved health status at 6 months,” Thomas J. Ford, MBChB(Hons), MRCP(UK), FRACP, British Heart Foundation research fellow at West of Scotland Regional Heart and Long Centre in Clydebank and British Heart Foundation clinical research fellow at the Institute of Cardiovascular and Medical Sciences at University of Glasgow, Scotland, said during the press conference. “Patients were feeling better with less angina and a better quality of life.”
Researchers analyzed data from 391 patients with angina and without obstructive CAD who were referred for an invasive coronary angiogram.
Baseline was the day of the clinically indicated invasive coronary angiogram, when researchers received consent to be a part of the procedure before knowing the patient’s coronary anatomy. Patients then completed questionnaires including the Seattle Angina Questionnaire and the EuroQOL five dimensions questionnaire (EQ-5D).
Patients without obstructive CAD (n = 151) based on the angiogram were assigned an interventional diagnostic procedure with stratified therapy (n = 75) or a masked sham procedure with standard care (n = 76).
“We do a short interventional diagnostic procedure,” Ford said during the press conference. “This lasts about 20 minutes, and we measure a few metrics to look at coronary artery function. This includes an acetylcholine stress test to assess increased contractility of the microcirculation or epicardial vasospasm.”
The primary endpoint was a change in the Seattle Angina Questionnaire score at 6 months.
At 6 months, patients assigned the intervention had a greater improvement in angina score compared with the control group (between-group difference = 11.7 U; 95% CI, 5-18.4; P = .001).
“This was driven by an improvement in physical limitation and an improvement in angina frequency,” Ford said during the press conference. “These patients were feeling better with less angina after the right diagnosis was made allowing tailored therapy.”
Patients in the intervention group also had improvements in the mean QOL score (EQ-5D index = 0.1 U; 95% CI, 0.01-0.18; P = .024) and visual analogue score (14.5 U; 95% CI, 7.8-21.3; P < .001), according to the simultaneous publication in the Journal of the American College of Cardiology.
At 6 months, there was no difference between the groups in MACE (2.6% for both groups; P = 1).
A possible angina diagnosis before randomization due to a coronary artery function disorder was seen in 46.1% of patients in the control group and 46.7% of those in the intervention group. After randomization, the frequency of diagnosis increased in patients assigned the intervention, although this was not seen in those assigned the control (88% vs. 46.1%; RR = 1.91; 95% CI, 1.48-2.47).
The two most common causes of ischemia in patients with no obstructive coronary disease are microvascular and vasospastic angina. The standard care angiogram has limited ability to detect these important functional coronary disorders, Ford said.
“This diagnostic procedure had clinical utility,” Ford said during the press conference. “There were more certain diagnoses, and 1 in 3 patients in standard care walked out the cath lab with a missed diagnosis of either microvascular or vasospastic angina. Physicians were almost three times more inclined to change angina therapy to treat the functional coronary disorder.” – by Darlene Dobkowski
References:
Ford TJ, et al. Late-Breaking Clinical Science 3. Presented at: TCT Scientific Symposium; Sept. 21-25, 2018; San Diego.
Ford TJ, et al. J Am Coll Cardiol. 2018;doi:10.1016/j.jacc.2018.09.006.
Disclosure: The study was funded by the British Heart Foundation. Ford reports no relevant financial disclosures.