BACKGROUND: Although increased coronary microvascular resistance (CMR), resulting in coronary microvascular dysfunction, is speculated to be responsible for myocardial ischemia in patients with cardiac syndrome X (CSX), it has never been directly demonstrated, and the correlation between CMR and severity of myocardial ischemia has not been elucidated in this setting. This study aimed to ascertain the increased CMR directly and to explore the relationship between CMR and severity of ischemia in patients with CSX. METHODS AND RESULTS: We studied 18 patients with CSX and 18 age- and sex-matched control subjects. Thermodilution-derived coronary flow reserve and index of microvascular resistance were measured using a pressure-temperature sensor-tipped coronary wire. Exercise treadmill test was performed by the Bruce protocol for calculating Duke treadmill score. Coronary flow reserve was significantly lower (2.37±0.81 versus 3.68±0.72; P<0.001) and index of microvascular resistance was higher (33.1±7.9 versus 18.8±5.6 U; P<0.001) in patients with CSX compared with those in control subjects. The Duke treadmill score was correlated positively to coronary flow reserve (r=0.539; P=0.021) and negatively to index of microvascular resistance (r=-0.742; P<0.001) in patients with CSX. CONCLUSIONS: Using an intracoronary thermodilution method, we for the first time directly demonstrated an increased microvascular resistance in patients with CSX. Furthermore, severity of ischemia was found to be intimately associated with CMR in this setting.
BACKGROUND: Although increased coronary microvascular resistance (CMR), resulting in coronary microvascular dysfunction, is speculated to be responsible for myocardial ischemia in patients with cardiac syndrome X (CSX), it has never been directly demonstrated, and the correlation between CMR and severity of myocardial ischemia has not been elucidated in this setting. This study aimed to ascertain the increased CMR directly and to explore the relationship between CMR and severity of ischemia in patients with CSX. METHODS AND RESULTS: We studied 18 patients with CSX and 18 age- and sex-matched control subjects. Thermodilution-derived coronary flow reserve and index of microvascular resistance were measured using a pressure-temperature sensor-tipped coronary wire. Exercise treadmill test was performed by the Bruce protocol for calculating Duke treadmill score. Coronary flow reserve was significantly lower (2.37±0.81 versus 3.68±0.72; P<0.001) and index of microvascular resistance was higher (33.1±7.9 versus 18.8±5.6 U; P<0.001) in patients with CSX compared with those in control subjects. The Duke treadmill score was correlated positively to coronary flow reserve (r=0.539; P=0.021) and negatively to index of microvascular resistance (r=-0.742; P<0.001) in patients with CSX. CONCLUSIONS: Using an intracoronary thermodilution method, we for the first time directly demonstrated an increased microvascular resistance in patients with CSX. Furthermore, severity of ischemia was found to be intimately associated with CMR in this setting.
Authors: Felipe Díez-Delhoyo; Enrique Gutiérrez-Ibañes; Gerard Loughlin; Ricardo Sanz-Ruiz; María Eugenia Vázquez-Álvarez; Fernando Sarnago-Cebada; Rocío Angulo-Llanos; Ana Casado-Plasencia; Jaime Elízaga; Francisco Fernández Avilés Diáz Journal: World J Cardiol Date: 2015-09-26
Authors: Federico Marin; Roberto Scarsini; Dimitrios Terentes-Printzios; Rafail A Kotronias; Flavio Ribichini; Adrian P Banning; Giovanni Luigi De Maria Journal: Curr Cardiol Rev Date: 2022
Authors: Alexander Liu; Rohan S Wijesurendra; Joanna M Liu; John C Forfar; Keith M Channon; Michael Jerosch-Herold; Stefan K Piechnik; Stefan Neubauer; Rajesh K Kharbanda; Vanessa M Ferreira Journal: J Am Coll Cardiol Date: 2018-03-06 Impact factor: 24.094
Authors: David C Tong; Robert Whitbourn; Andrew MacIsaac; Andrew Wilson; Andrew Burns; Sonny Palmer; Jamie Layland Journal: Front Cardiovasc Med Date: 2018-01-12