Impaired coronary flow reserve as a marker of microvascular dysfunction to predict long-term cardiovascular outcomes, acute coronary syndrome and the development of heart failure.
BACKGROUND
In the absence of obstructive coronary narrowing, impaired coronary flow reserve (CFR) represents coronary microvascular dysfunction. Transthoracic Doppler echocardiography (TTDE) allows non-invasive measurement of CFR in the left anterior descending (LAD) artery. This study aimed to assess the prognostic value of TTDE-derived CFR (as a marker of microvascular function) in predicting long-term cardiovascular events, acute coronary syndrome (ACS) events, and the development of heart failure (HF).


RESULTS
This study consisted of 272 patients with coronary artery disease not involving obstructive narrowing (≥50%) in the LAD. Patients underwent TTDE examination for CFR measurement in the LAD. During the follow-up period of 4.0±1.9 years, 32 patients (12%) had cardiovascular events. Cox proportional hazard analysis identified lower CFR as an independent risk factor of cardiovascular events (P<0.001), ACS events (P=0.008), and HF development (P=0.003). A CFR less than 2.4 was the best cut-off value for predicting all events (area under the curve=0.82). CFR excellently predicted the development of HF (area under the curve=0.95), but not ACS events (area under the curve=0.67).


CONCLUSIONS
This TTDE study demonstrated that CFR was a significant and independent determinant of long-term cardiovascular events, ACS events and HF in patients with coronary artery disease. A CFR greater than 2.0 was not suitable to predict a favorable long-term outcome, even in the absence of obstructive coronary narrowing.
Department of Internal Medicine and Cardiology, Osaka City University Graduate School of Medicine, Osaka, Japan.
Koki
K
Nakanishi
Shota
S
Fukuda
Kenei
K
Shimada
Chinami
C
Miyazaki
Kenichiro
K
Otsuka
Kumiko
K
Maeda
Reiko
R
Miyahana
Takahiko
T
Kawarabayashi
Hiroyuki
H
Watanabe
Junichi
J
Yoshikawa
Minoru
M
Yoshiyama
D054058:Acute Coronary Syndrome / Q000000981:diagnostic imaging / Q000503:physiopathology*; D000368:Aged; D000369:Aged, 80 and over; D003326:Coronary Circulation; D004452:Echocardiography; D005260:Female; D006333:Heart Failure / Q000000981:diagnostic imaging / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008833:Microcirculation; D008875:Middle Aged; D011237:Predictive Value of Tests; D012307:Risk Factors