PHILADELPHIA – Longer and more extensive follow-up of the positive CorMicA trial confirmed that clinicians who receive added information on the presence or absence of microvascular coronary disease or coronary vasospasm in patients with chronic, stable angina but without detectable coronary obstruction adjust patient treatment in ways that produce better outcomes.
For example, expanded 1-year follow-up of the 151-patient, multicenter, CorMicA randomized study showed that stable angina patients without coronary obstruction treated by clinicians aware of microvascular or vasospastic coronary disease had blood pressures that averaged about 12/5 mm Hg lower than those of patients in the control arm, in which this information was kept blinded.
Clinicians in the study who received information about diagnoses of microvascular angina, vasospastic angina, both, or neither, generally better tailored the treatments they gave these patients, were more likely to prescribe cardiac rehabilitation to these patients, and successfully capped increases in blood pressure that occurred in the control patients,, said at the American Heart Association scientific sessions. The investigators made the diagnoses of microvascular and vasospastic angina using an “invasive diagnostic procedure” that involved placing a wire with pressure and temperature sensors in a selected coronary artery and measuring flow patterns that resulted from a systemic infusion of adenosine and from incremental, intracoronary infusions of acetylcholine.
The CorMicA results “tell us that, if we use existing drugs and nonpharmacologic treatments, we can improve patients’ quality of life,” said Dr. Berry, co-lead investigator of the study and professor of cardiology and imaging at the University of Glasgow. “There were probably two drivers of change in treatment” between the intervention arm where clinicians learned whether their patients had microvascular angina or vasospasm, and the control arm where this information was kept blinded. Some patients reclassified as having microvascular disease or vasospasm were restarted on standard agents for treatment of coronary artery disease such as statins and ACE inhibitors that had previously been stopped, noted Dr. Berry. The identification of a specific type of vascular disorder also helped guide treatment. For example, patients identified as having vasospasm were taken off of beta-blockers, which are contraindicated in these patients, and instead began treatment with a calcium channel antagonist, he said.
“CorMicA was a landmark trial. The interventional cardiologists at my center believe that the testing [for microvascular and vasospastic angina] should be used routinely, based on the reported data,” said, a cardiologist at NYU Langone Health in New York.
The(Coronary Microvascular Angina) trial enrolled 391 patients at either of two hospitals in Scotland during November 2016–November 2017. All patients were scheduled for clinically indicated, elective diagnostic angiography for suspected stable angina. Clinicians identified a coronary obstruction in 206 patients that excluded them from the main CorMicA analysis. They focused on the 181 without coronary obstruction visible by angiography, and specifically the 151 of these patients who underwent the invasive diagnostic procedure, with 76 randomized to have their diagnostic-procedure results relayed to their treating physicians and 75 patients whose diagnostic results remained blinded. The study’s primary endpoint was the mean difference in angina severity at 6 months after treatment assessed by the Seattle Angina Questionnaire (SAQ) summary score. After 6 months, the between-group difference in average SAQ summary scores was 11.7 units, a statistically significant as well as clinically meaningful benefit that linked with knowledge of the coronary function of patients based on invasive testing ( ).
The prespecified 1-year follow-up with another SAQ took place for 142 of the 151 randomized patients, and showed ongoing separation of SAQ scores between the intervention and control patients, reaching a statistically significant mean difference of 13.6 units, Dr. Berry reported. Other benefits that linked with dissemination of results from the invasive diagnostic procedure included maintenance of the quality-of-life benefit seen after 6 months, an incremental further reduction in illness perception from 6 to 12 months, and a substantial further improvement in global treatment satisfaction, which grew from a 30% higher level in the intervention group compared with controls at 6 months to a 44% between-group difference after 12 months. Concurrently with Dr. Berry’s report, the results appeared online (JACC: Cardiovasc Interv.).
Additional findings for various clinical measures that were not part of the 6-month findings provided further insight into the impact that clinician knowledge about microvascular disease or vasospasm had on patients. These metrics suggested that the benefits in the intervention patients may have largely resulted from their avoiding elevations in risk markers that occurred among controls who received routine care.
For example, after 12 months, average 12/5 mm Hg differences in systolic and diastolic blood pressures between the two arms was nearly all because of pressure increases from baseline in the control patients with only very small drops in pressure from baseline among the intervention patients. Weight measurements after 1 year showed that the control patients were on average 1.3 kg heavier than the intervention patients, again mostly because of weight increases among the controls. Enrollment in a cardiac rehabilitation program at 12 months had occurred for 40% of the intervention patients and 16% of the controls, a 73% relative increase in the intervention arm, Dr. Berry reported.
The invasive, coronary, physiological assessments used in CorMicA led to stratified medical therapy and created an opportunity for better long-term angina treatment in patients without obstructive coronary disease, Dr. Berry concluded. He stressed the need to further test this hypothesis in larger, prospective studies, and to assess its cost effectiveness. But the proof-of-concept demonstrated by the CorMicA results indicate a role for more thorough investigation of coronary dysfunction when obstructive disease is absent, with the opportunity to use this information to better tailor treatment. The findings also highlight the potential for new drug development that can address nonobstructive microvascular or vasospastic coronary disease, he said.
Dr. Berry has been a speaker on behalf of Abbott Vascular, and he has received research funding from AstraZeneca, GlaxoSmithKline, HeartFlow, Novartis, and Siemens Healthcare. Dr. Reynolds had no disclosures.
SOURCE: Ford TJ. AHA 2019, session FS.AOS.03 .