Disturbed Coronary Hemodynamics in Vessels With Intermediate Stenoses Evaluated With Fractional Flow Reserve

• Original Article
  • Coronary Heart Disease

Disturbed Coronary Hemodynamics in Vessels With Intermediate Stenoses Evaluated With Fractional Flow Reserve

A Combined Analysis of Epicardial and Microcirculatory Involvement in Ischemic Heart Disease

1. Mauro Echavarria-Pinto, MD; 
2. Javier Escaned, MD, PhD; 
3. Enrico Macías, MD; 
4. Miguel Medina, MD; 
5. Nieves Gonzalo, MD, PhD; 
6. Ricardo Petraco, MD;
7. Sayan Sen, MBBS; 
8. Pilar Jimenez-Quevedo, MD, PhD; 
9. Rosana Hernandez, MD, PhD; 
10. Rafael Mila, MD; 
11. Borja Ibañez, MD, PhD; 
12. Ivan J. Nuñez-Gil, MD; 
13. Cristina Fernández, MD, PhD; 
14. Fernando Alfonso, MD, PhD;
15. Camino Bañuelos, MD; 
16. Eulogio García, MD; 
17. Justin Davies, MBBS, PhD;
18. Antonio Fernández-Ortiz, MD, PhD; 
19. Carlos Macaya, MD, PhD

+Author Affiliations

1. From the Cardiovascular Institute, Hospital Clinico San Carlos, Madrid, Spain (M.E.-P., J.E., E.M., M.M., N.G., P.J.-Q., R.H., R.M. B.I., I.J.N.-G., F.A., C.B., E.G., A.F.-O., C.M.); Centro Nacional de Investigaciónes Cardiovasculares Carlos III (CNIC), Madrid, Spain (M.E.-P., J.E., B.I., A.F.-O.); Imperial College Healthcare and NHS Trust, London, UK (R.P., S.S., J.D.); and Clinical Epidemiology Unit, Hospital Clinico San Carlos, Madrid, Spain (C.F.).

1. Correspondence to Javier Escaned, MD, PhD, Instituto Cardiovascular, Hospital Clinico San Carlos, Madrid, Spain, Centro Nacional de Investigaciónes Cardiovasculares Carlos III (CNIC), Madrid, Spain. E-mail escaned@secardiologia.es

Abstract

Background—In chronic ischemic heart disease, focal stenosis, diffuse atherosclerotic narrowings, and microcirculatory dysfunction (MCD) contribute to limit myocardial flow. The prevalence of these ischemic heart disease levels in fractional flow reserve (FFR) interrogated vessels remains largely unknown.

Methods and Results—Using intracoronary measurements, 91 coronaries (78 patients) with intermediate stenoses were classified in 4 FFR and coronary flow reserve (CFR) agreement groups, using FFR>0.80 and CFR<2 as cutoffs. Index of microcirculatory resistance (IMR) and atherosclerotic burden (Gensini score) were also assessed. MCD was assumed when IMR≥29.1 (75^th percentile). Fifty-four (59.3%) vessels had normal FFR, from which only 20 (37%) presented both normal CFR and IMR. Among vessels with FFR>0.80, most (63%) presented disturbed hemodynamics: abnormal CFR in 28 (52%) and MCD in 18 (33%). Vessels with FFR>0.80 presented higher IMR [adjusted mean 27.6 (95% confidence interval, 23.4–31.8)] than those with FFR≤0.80 [17.3 (95% confidence interval, 13.0–21.7), p=0.001]. Atherosclerotic burden was inversely correlated with CFR (r=−0.207,P=0.055), and in vessels with FFR>0.80 and CFR<2 (n=28, 39%), IMR had a wide dispersion (7–72.7 U), suggesting a combination of diffuse atherosclerotic narrowings and MCD. Vessels with FFR≤0.80 and normal CFR presented the lowest IMR, suggesting a preserved microcirculation.

Conclusions—A substantial number of coronary arteries with stenoses showing an FFR>0.80 present disturbed hemodynamics. Integration of FFR, CFR, and IMR supports the existence of differentiated patterns of ischemic heart disease that combine focal and diffuse coronary narrowings with variable degrees of MCD.

Key Words:

• coronary disease
• microcirculation
• physiology

• Received January 16, 2013.
• Accepted August 30, 2013.

• © 2013 American Heart Association, Inc.