Abstract 13143: The Relationship Between Coronary Microvascular Dysfunction and Preclinical Left Ventricular Diastolic Dysfunction: Invasive Physiologic and Echocardiographic Study
Background: Microvascular dysfunction has been associated with the development of diastolic heart failure. We hypothesized that invasively assessed microvasculature is related to diastolic function as assessed by echocardiography, even before the development of diastolic heart failure.
Methods: We prospectively enrolled 63 subjects with preserved ejection fraction (≥55%) and no heart failure symptoms. Coronary physiologic assessment, including fractional flow reserve (FFR), coronary flow reserve (CFR), and the index of microcirculatory resistance (IMR), was performed in the LAD. Coronary flow was assessed with a thermodilution method by obtaining a mean transit time (Tmn: an inverse correlate to absolute flow) at rest and hyperemia. IMR was measured as distal coronary pressure x hyperemic Tmn. Left ventricular diastolic function was evaluated by an echocardiographic parameter (E/e’) using the following criteria; normal E/e’<8, intermediate 8<E/e’<15, and high E/e’>15, where a higher value was correlated with diastolic dysfunction.
Results: Mean age was 54.5±12.3 years. All subjects had no significant stenosis in the LAD (FFR: 0.87±0.05). Mean CFR and IMR were 4.4±1.9 and 18.2±8.3, respectively. CFR and IMR were not significantly different among the 3 E/e’ groups (ANOVA p=0.60 for CFR and p=0.14 for IMR). Conversely, both resting and hyperemic Tmn were significantly shorter in patients with a high E/e’ value than with a normal value (p=0.04 for resting Tmn and p=0.03 for hyperemic Tmn, Figure), suggesting that coronary flow both at rest and hyperemia increases along with the progression of diastolic dysfunction.
Conclusions: In this preclinical population, invasively assessed microvascular function (CFR/IMR) is not associated with diastolic dysfunction, whereas both resting and hyperemic flow are increased in subjects with diastolic dysfunction. Future studies are warranted to test the prognostic value of increased coronary flow.
Author Disclosures: Y. Kobayashi: Research Grant; Significant; Boston Scientific. Honoraria; Modest; Volcano. Y. Kobayashi: None. F. Haddad: None. V. Pargaonkar: None. D.P. Lee: None. W.F. Fearon: None. A.C. Yeung: None. J.A. Tremmel: None.
- © 2015 by American Heart Association, Inc.