Adding stress myocardial CT perfusion imaging to examinations with CT angiography may safely increase diagnostic specificity and reduce the need for invasive treatments in patients with possible ischemic heart disease, according to a study published in JACC: Cardiovascular Imaging.
“This is the first randomized trial to assess the clinical value of a combined CTA and CT [perfusion imaging] examination as part of the post-discharge diagnostic work-up in patients with recent hospitalization for acute-onset chest pain, in whom ACS had been ruled out,” Mathias H. Sørgaard, MD, of the department of cardiology at The Heart Centre, Rigshospitalet, University of Copenhagen, Denmark, and colleagues wrote. “The combined strategy had no significant impact on our primary endpoint — the frequency of coronary revascularization among patients referred for [invasive coronary angiography]. However, addition of CT [perfusion imaging] to coronary CTA examination substantially reduced the number of patients referred for [invasive coronary angiography] and the total number of coronary revascularizations.”
To compare the effectiveness of CTA alone with CTA plus CT perfusion imaging, researchers conducted the CATCH-2 randomized controlled trial between October 2013 and March 2017 wherein patients aged 50 years or older were prospectively randomly assigned examination with coronary CTA (n = 300; mean age, 63.5 years; 48% men) or coronary CTA plus CT perfusion imaging (n = 300; mean age, 62.9 years; 51% men).
Independent readers, masked to group assignments, analyzed coronary CTA images and then, if applicable, were presented with CT perfusion imaging images.
Patients in the coronary CTA group were referred for invasive coronary angiography if they had at least 50% stenosis in a coronary artery with a diameter of at least 2 mm, whereas patients in the coronary CTA plus CT perfusion imaging group were referred if they had at least 50% stenosis in a coronary artery with a diameter of at least 2 mm and a corresponding reversible myocardial perfusion defect.
The primary endpoint was the frequency of coronary revascularization in patients referred for invasive coronary angiography, which was based on index CT evaluation. Secondary endpoints included invasive procedural complications at index-related invasive coronary angiography, post-index cardiac death, hospital admittance due to the recurrence of chest pain, unstable angina or acute MI/invasive coronary angiography/revascularization.
Patients were followed up for a median of 1.5 years. During this time, the occurrence of secondary endpoints was similar between the two groups.
Fewer invasive procedures
Researchers found that the primary endpoint occurred in 50% of patients in the coronary CTA and in 48% of invasively examined patients (P = .85), whereas the number of revascularizations was 7% in the CTA plus CT perfusion imaging group and 14% in the CTA group (P = .0045).
In total, 14% of patients in the CTA plus CT perfusion imaging group and 30% of those in the CTA group were referred for invasive coronary angiography (P < .0001).
“A post-discharge diagnostic strategy of combined coronary CT angiography and CT myocardial perfusion imaging safely reduces the need for invasive coronary intervention while maintaining a low angina pectoris burden in patients with suspected [ischemic heart disease],” the researchers concluded. – by Melissa J. Webb
Disclosures: Sørgaard reports receiving research grants from The Research Council of Rigshospitalet and lecturing fees from Toshiba Medical Systems Corp. Please see the study for all other authors’ relevant financial disclosures.