Invasive endotyping clarifies unexplained chest pain, but no improvement in symptom burden
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Key takeaways:
- Compared with CT coronary angiography alone, coronary function testing improved endotype diagnosis for angina with nonobstructive CAD.
- Endotype diagnosis improved treatment satisfaction, but not angina burden.
In patients with angina with nonobstructive CAD, invasive testing increased the likelihood of an angina endotype diagnosis and improved treatment satisfaction compared with controls, but did not improve angina burden, researchers reported.
Only one in five patients have obstructive CAD, which leaves most patients with unexplained chest pain symptoms after undergoing CT coronary angiography, Novalia Sidik, MBChB, an honorary clinical lecturer at the School of Cardiovascular and Metabolic Health at the University of Glasgow and an academic researcher at Golden Jubilee National Hospital, Scotland, said during a late-breaking clinical trial presentation. The prevalence of coronary endotypes, such as vasospastic angina and microvascular angina, are unclear, Sidik said.
Image: Adobe Stock
For the randomized controlled blinded CorCTCA study, Sidik and colleagues analyzed data from 231 patients with suspected angina without obstructive CAD (ANOCA) after undergoing CT coronary angiography. Researchers assessed whether endotype diagnosis informed by coronary function testing in conjunction with endotype-specific treatment algorithms (n = 115) improved angina and treatment satisfaction compared with no functional assessment (controls; n = 116).
Study objectives were to assess the prevalence of ANOCA endotypes; to assess the reclassification on the final diagnosis based on the disclosure of coronary function testing to the interventional cardiologist; and to assess the effect of the intervention on health status, Sidik said. Patients were randomly assigned in the cath lab to the intervention or to usual care.
“In the intervention group, the attending cardiologist remained in the cath lab and had full knowledge of the coronary function test results,” Sidik said during the presentation. “In the control group, the cardiologist left the cath lab and had no knowledge of the coronary function test results. At the end of the procedure, the attending cardiologist made a diagnosis based on the knowledge that they had. They were also provided with endotype-specific guidance for the management and treatment of that specific endotype.”
The prespecified primary outcome was the between-group difference in reclassification rate.
In the intervention group, the likelihood of a diagnosis of microvascular angina and/or vasospastic angina increased fourfold (OR = 4.05; 95% CI, 2.32-7.24; P < .001). The frequency of diagnosis of microvascular angina and/or vasospastic angina increased from 48.7% to 76.5%, Sidik said, adding that there was also a reduction in the diagnosis of noncardiac chest pain in the intervention group (pre-randomization, 51.3%; post-randomization, 23.5%; P < .001).
During median follow-up of 20 months, there was no between-group difference in angina burden at all time points measured, consistent across the five domains of the Seattle Angina Questionnaire (global P = .36), Sidik said. One in five patients had unplanned episodes of hospital care for chest pain during follow-up.
“This reflects a high burden for health care resources despite the mild angina at baseline,” Sidik said.
Compared with controls, the intervention group had a statistically significant increase in treatment satisfaction (P = .013), a reduction in systolic BP (P = .044), more patients with systolic BP less than 130 mm Hg (P = .051) and a reduction in additional referrals for further investigations for CV and non-CV causes (P = .014 for CV causes; P < .001 for non-CV causes).
“Invasive endotyping clarified the cause of chest pain in this population of patients with ANOCA and improved treatment satisfaction but not angina burden,” Sidik said.
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Sidik N, et al. Late-breaking clinical data: Focus on wire and image-based physiology. Presented at: EuroPCR; May 16-19, 2023; Paris (hybrid meeting).
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