Non-ischemic phenotypes of low risk chest pain patients based on exercise stress-echocardiography: the pilot study

Tamara Ryabova Elena Abramenko ^* Ivan Yolgin Konstantin Zavadovsky Vyacheslav Ryabov

• Federal State Budgetary Scientific Institution ‘Tomsk National Research Medical Center of the Russian Academy of Sciences’ (Tomsk NRMC), Tomsk, Russia

A significant proportion (~85%) of low risk NSTE-ACS patients do not receive objective confirmation of ischemia by SE, but yet remain a healthcare burden due to lower long-term survival and overuse of medical services. We aimed to identify non-ischemic phenotypes in low risk NSTE-ACS patients using a wide range of parameters available during ExSE.In-patients (n=103, median age 56 (46; 65) years, 65 (63%) men) with suspected NSTE-ACS without high risk criteria underwent ExSE on a semi-supine cycle ergometer. The abnormal stress biomarkers (RWMA, ST-segment depression, induced angina; peak systolic blood pressure, CR, HRR, low exercise capacity) were used for phenotyping. Non-ischemic phenotypes were defined as not belonging to the clusters with the highest rates of RWMA, STsegment depression and induced angina. Invasive or noninvasive coronary angiography was used to assess coronary anatomy.The majority (90%) of patients present with one or more abnormal stress biomarkers. Cluster analysis revealed 6 phenotypes, 4 of them were classified as non-ischemic, identified in 65 (63%) patients. Non-ischemic phenotypes differed in the frequency of hypertensive response, reduced CR, and reduced HRR. In non-ischemic phenotypes patients was low (23%) incidence of CAD.Four non-ischemic phenotypes of low risk NSTE-ACS patients have been identified: «nearnormal type», «inotropic insufficiency type», «hypertensive type», «chronotropic insufficiency type». Further studies are needed to investigate the significance of the obtained phenotypes in the long-term period.