Fernando Rivero1, Alejandro Gutiérrez-Barrios2, Josep Gomez-Lara3, Manuel Fuentes-Ferrer4, Javier Cuesta1, Danielle C J Keulards5, Ana Pardo-Sanz6, Teresa Bastante1, Elena Izaga-Torralba2, Joan-Antoni Gomez-Hospital3, Marcos García-Guimaraes7, Nico H J Pijls5, Fernando Alfonso8. 1. Hospital Universitario de la Princesa, IIS-IP, CIBERCV, Madrid, Spain. 2. Hospital Universitario Puerta del Mar, Cadiz, Spain. 3. Hospital Universitari de Bellvitge, Institut d' Investigació Biomèdica de Bellvitge (IDIBELL), Universitat de Barcelona, L' Hospitalet de Llobregat, Spain. 4. Department of Preventive Medicine, Hospital Clínico San Carlos, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos, Madrid, Spain. 5. Department of Cardiology, Catharina Hospital, Eindhoven, the Netherlands. 6. Hospital Universitario Ramón y Cajal, Madrid, Spain. 7. Servicio de Cardiología, Hospital del Mar - Parc de Salut Mar, Barcelona, Grupo de Investigación Biomédica en Enfermedades del Corazón, IMIM (Instituto Hospital del Mar de Investigaciones Médicas), Barcelona, Spain. 8. Hospital Universitario de la Princesa, IIS-IP, CIBERCV, Madrid, Spain. Electronic address: falf@hotmail.com.
Abstract
BACKGROUND: This study aimed to assess the correlation between the standard of care, the index of microvascular resistance (IMR) versus the novel microvascular resistance (Rmicro) and to determine the pathologic cut-off value in a selected population with suspected coronary microvascular dysfunction (CMD). METHODS: One-hundred and twenty patients with high clinical suspicion of CMD due to ischemic symptoms in the absence of significant epicardial coronary lesions were prospectively included. Following a standardized systematic protocol, coronary flow reserve, IMR, fractional flow reserve, Q and Rmicro were measured in the left anterior descending coronary artery using a temperature/pressure sensor-tipped guidewire and a dedicated infusion catheter. RESULTS: There was a high prevalence of CMD with 50 (42%) patients showing an IMR ≥ 25. Median IMR was 23 [IQR: 14-34] and median Rmicro was 464 Woods Units (WU) [IQR: 354-636WU]. ROC analyses identified 500 WU as the optimal Rmicro cut-off to identify patients with an IMR ≥ 25, with an area under the ROC curve (C statistic) of 0.83 (95% CI: 0.74 to 0.89, p < 0.0001). CONCLUSIONS: Rmicro derived from continuous intracoronary thermodilution is an accurate index to measure microvascular resistances enabling the invasive diagnostic of CMD.
BACKGROUND: This study aimed to assess the correlation between the standard of care, the index of microvascular resistance (IMR) versus the novel microvascular resistance (Rmicro) and to determine the pathologic cut-off value in a selected population with suspected coronary microvascular dysfunction (CMD). METHODS: One-hundred and twenty patients with high clinical suspicion of CMD due to ischemic symptoms in the absence of significant epicardial coronary lesions were prospectively included. Following a standardized systematic protocol, coronary flow reserve, IMR, fractional flow reserve, Q and Rmicro were measured in the left anterior descending coronary artery using a temperature/pressure sensor-tipped guidewire and a dedicated infusion catheter. RESULTS: There was a high prevalence of CMD with 50 (42%) patients showing an IMR ≥ 25. Median IMR was 23 [IQR: 14-34] and median Rmicro was 464 Woods Units (WU) [IQR: 354-636WU]. ROC analyses identified 500 WU as the optimal Rmicro cut-off to identify patients with an IMR ≥ 25, with an area under the ROC curve (C statistic) of 0.83 (95% CI: 0.74 to 0.89, p < 0.0001). CONCLUSIONS: Rmicro derived from continuous intracoronary thermodilution is an accurate index to measure microvascular resistances enabling the invasive diagnostic of CMD.