{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,19]],"date-time":"2026-10-19T16:29:33Z","timestamp":1792427373156,"version":"4.5.0"},"reference-count":41,"publisher":"Ovid Technologies (Wolters Kluwer Health)","issue":"22","content-domain":{"domain":["www.ahajournals.org"],"crossmark-restriction":true},"short-container-title":["Circulation"],"published-print":{"date-parts":[[2019,11,26]]},"abstract":"<jats:sec>\n            <jats:title>Background:<\/jats:title>\n            <jats:p>Coronary microvascular dysfunction (MVD) is defined by impaired flow augmentation in response to a pharmacological vasodilator in the presence of nonobstructive coronary artery disease. It is unknown whether diminished coronary vasodilator response correlates with abnormal exercise physiology or inducible myocardial ischemia.<\/jats:p>\n          <\/jats:sec>\n          <jats:sec>\n            <jats:title>Methods:<\/jats:title>\n            <jats:p>Patients with angina and nonobstructive coronary artery disease had simultaneous coronary pressure and flow velocity measured using a dual sensor-tipped guidewire during rest, supine bicycle exercise, and adenosine-mediated hyperemia. Microvascular resistance (MR) was calculated as coronary pressure divided by flow velocity. Wave intensity analysis quantified the proportion of accelerating wave energy (perfusion efficiency). Global myocardial blood flow and subendocardial:subepicardial perfusion ratio were quantified using 3-Tesla cardiac magnetic resonance imaging during hyperemia and rest; inducible ischemia was defined as hyperemic subendocardial:subepicardial perfusion ratio &lt;1.0. Patients were classified as having MVD if coronary flow reserve &lt;2.5 and controls if coronary flow reserve \u22652.5, with researchers blinded to the classification.<\/jats:p>\n          <\/jats:sec>\n          <jats:sec>\n            <jats:title>Results:<\/jats:title>\n            <jats:p>\n              Eighty-five patients were enrolled (78% female, 57\u00b110 years), 45 (53%) were classified as having MVD. Of the MVD group, 82% had inducible ischemia compared with 22% of controls (\n              <jats:italic>P<\/jats:italic>\n              &lt;0.001); global myocardial perfusion reserve was 2.01\u00b10.41 and 2.68\u00b10.49 (\n              <jats:italic>P<\/jats:italic>\n              &lt;0.001). In controls, coronary perfusion efficiency improved from rest to exercise and was unchanged during hyperemia (59\u00b111% vs 65\u00b114% vs 57\u00b118%;\n              <jats:italic>P<\/jats:italic>\n              =0.02 and\n              <jats:italic>P<\/jats:italic>\n              =0.14). In contrast, perfusion efficiency decreased during both forms of stress in MVD (61\u00b112 vs 44\u00b110 vs 42\u00b111%; both\n              <jats:italic>P<\/jats:italic>\n              &lt;0.001). Among patients with a coronary flow reserve &lt;2.5, 62% had functional MVD, with normal minimal MR (hyperemic MR&lt;2.5 mmHg\/cm\/s), and 38% had structural MVD with elevated hyperemic MR. Resting MR was lower in those with functional MVD (4.2\u00b11.0 mmHg\/cm\/s) than in those with structural MVD (6.9\u00b11.7 mmHg\/cm\/s) or controls (7.3\u00b12.2 mmHg\/cm\/s; both\n              <jats:italic>P<\/jats:italic>\n              &lt;0.001). During exercise, the structural group had a higher systolic blood pressure (188\u00b125 mmHg) than did those with functional MVD (161\u00b127 mmHg;\n              <jats:italic>P<\/jats:italic>\n              =0.004) and controls (156\u00b130 mmHg;\n              <jats:italic>P<\/jats:italic>\n              &lt;0.001). Functional and structural MVD had similar stress myocardial perfusion and exercise perfusion efficiency values.\n            <\/jats:p>\n          <\/jats:sec>\n          <jats:sec>\n            <jats:title>Conclusion:<\/jats:title>\n            <jats:p>In patients with angina and nonobstructive coronary artery disease, diminished coronary flow reserve characterizes a cohort with inducible ischemia and a maladaptive physiological response to exercise. We have identified 2 endotypes of MVD with distinctive systemic vascular responses to exercise; whether endotypes have a different prognosis or require different treatments merits further investigation.<\/jats:p>\n          <\/jats:sec>","DOI":"10.1161\/circulationaha.119.041595","type":"journal-article","created":{"date-parts":[[2019,11,11]],"date-time":"2019-11-11T10:02:00Z","timestamp":1573466520000},"page":"1805-1816","update-policy":"https:\/\/doi.org\/10.1161\/crossmarkpolicy","source":"Crossref","is-referenced-by-count":209,"title":["Coronary Microvascular Dysfunction Is Associated With Myocardial Ischemia and Abnormal Coronary Perfusion During Exercise"],"prefix":"10.1161","volume":"140","author":[{"given":"Haseeb","family":"Rahman","sequence":"first","affiliation":[{"name":"From The British Heart Foundation Centre of Research Excellence, Schools of Cardiovascular Medicine &amp; Sciences (H.R., M.R., M.L., B.M., H.M., H.E., B.C., M.M., A.W., D.P.), King\u2019s College London, United Kingdom."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Matthew","family":"Ryan","sequence":"additional","affiliation":[{"name":"From The British Heart Foundation Centre of Research Excellence, Schools of Cardiovascular Medicine &amp; Sciences (H.R., M.R., M.L., B.M., H.M., H.E., B.C., M.M., A.W., D.P.), King\u2019s College London, United Kingdom."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Matthew","family":"Lumley","sequence":"additional","affiliation":[{"name":"From The British Heart Foundation Centre of Research Excellence, Schools of Cardiovascular Medicine &amp; Sciences (H.R., M.R., M.L., B.M., H.M., H.E., B.C., M.M., A.W., D.P.), King\u2019s College London, United Kingdom."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Bhavik","family":"Modi","sequence":"additional","affiliation":[{"name":"From The British Heart Foundation Centre of Research Excellence, Schools of Cardiovascular Medicine &amp; Sciences (H.R., M.R., M.L., B.M., H.M., H.E., B.C., M.M., A.W., D.P.), King\u2019s College London, United Kingdom."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hannah","family":"McConkey","sequence":"additional","affiliation":[{"name":"From The British Heart Foundation Centre of Research Excellence, Schools of Cardiovascular Medicine &amp; Sciences (H.R., M.R., M.L., B.M., H.M., H.E., B.C., M.M., A.W., D.P.), King\u2019s College London, United Kingdom."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Howard","family":"Ellis","sequence":"additional","affiliation":[{"name":"From The British Heart Foundation Centre of Research Excellence, Schools of Cardiovascular Medicine &amp; Sciences (H.R., M.R., M.L., B.M., H.M., H.E., B.C., M.M., A.W., D.P.), King\u2019s College London, United Kingdom."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Cian","family":"Scannell","sequence":"additional","affiliation":[{"name":"Biomedical Engineering &amp; Imaging Sciences 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