{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,25]],"date-time":"2026-09-25T22:45:28Z","timestamp":1790376328296,"version":"4.1.0"},"reference-count":17,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,5,8]],"date-time":"2026-05-08T00:00:00Z","timestamp":1778198400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Cardiovasc. Med."],"abstract":"<jats:sec>\n                    <jats:title>Aim<\/jats:title>\n                    <jats:p>This study investigated coronary slow flow (CSF) prevalence in post-COVID-19 patients presenting with unstable angina (UA) and angiographically normal coronary arteries.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Materials and methods<\/jats:title>\n                    <jats:p>The study included 190 patients presenting with unstable angina (UA) and confirmed normal coronary arteries via invasive angiography. Participants were divided into two age- and sex-matched groups: 95 patients with a history of COVID-19 [COVID (+) UA-NCA] and 95 patients without a prior history of the infection [COVID (\u2013) UA-NCA]. In the study group, COVID-19 was confirmed via RT-PCR and computed tomography. All participants underwent coronary angiography to perform Thrombolysis in Myocardial Infarction (TIMI) frame count (TFC) measurements. CSF was diagnosed in patients with a corrected TFC (CTFC)\u2009\u2265\u200927.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>\n                      CSF prevalence was significantly higher in the COVID (+) UA-NCA group than in the COVID (\u2013) UA-NCA group (18.9% vs. 5.3%,\n                      <jats:italic>p<\/jats:italic>\n                      \u2009=\u20090.003). Individual CTFC values for the LAD, LCX, and RCA were also significantly higher in the COVID (+) UA-NCA group compared to the COVID (\u2013) UA-NCA group (26.1\u2009\u00b1\u20094.3 vs. 22.4\u2009\u00b1\u20092.6 [\n                      <jats:italic>p<\/jats:italic>\n                      \u2009=\u20090.01], 24.3\u2009\u00b1\u20094.5 vs. 21.7\u2009\u00b1\u20092.4 [\n                      <jats:italic>p<\/jats:italic>\n                      \u2009&amp;lt;\u20090.001], and 24.3\u2009\u00b1\u20094.5 vs. 21.4\u2009\u00b1\u20092.5 [\n                      <jats:italic>p<\/jats:italic>\n                      \u2009&amp;lt;\u20090.001], respectively).\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>CSF prevalence is significantly higher in patients with a history of COVID-19, suggesting persistent microvascular impairment.<\/jats:p>\n                  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