Coronary microvascular function and myocardial fibrosis in women with angina pectoris and no obstructive coronary artery disease: the iPOWER studyReport as inadecuate

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Journal of Cardiovascular Magnetic Resonance

, 18:76

First Online: 04 November 2016Received: 11 June 2016Accepted: 12 October 2016


BackgroundEven in absence of obstructive coronary artery disease women with angina pectoris have a poor prognosis possibly due to coronary microvascular disease. Coronary microvascular disease can be assessed by transthoracic Doppler echocardiography measuring coronary flow velocity reserve CFVR and by positron emission tomography measuring myocardial blood flow reserve MBFR. Diffuse myocardial fibrosis can be assessed by cardiovascular magnetic resonance CMR T1 mapping. We hypothesized that coronary microvascular disease is associated with diffuse myocardial fibrosis.

MethodsWomen with angina, a clinically indicated coronary angiogram with <50 % stenosis and no diabetes were included. CFVR was measured using dipyridamole 0.84 mg-kg and MBFR using adenosine 0.84 mg-kg. Focal fibrosis was assessed by 1.5 T CMR late gadolinium enhancement 0.1 mmol-kg and diffuse myocardial fibrosis by T1 mapping using a modified Look-Locker pulse sequence measuring T1 and extracellular volume fraction ECV.

ResultsCFVR and CMR were performed in 64 women, mean SD age 62.5 8.3 years. MBFR was performed in a subgroup of 54 84 % of these women. Mean native T1 was 1023 86 and ECV % was 33.7 3.5; none had focal fibrosis. Median IQR CFVR was 2.3 1.9; 2.7, 23 36 % had CFVR < 2 indicating coronary microvascular disease, and median MBFR was 2.7 2.2; 3.0 and 19 35 % had a MBFR value below 2.5. No significant correlations were found between CFVR and ECV or native T1 R = 0.02; p = 0.27 and R = 0.004; p = 0.61, respectively. There were also no correlations between MBFR and ECV or native T1 R = 0.1; p = 0.13 and R = 0.004, p = 0.64, respectively. CFVR and MBFR were correlated to hypertension and heart rate.

ConclusionIn women with angina and no obstructive coronary artery disease we found no association between measures of coronary microvascular disease and myocardial fibrosis, suggesting that myocardial ischemia induced by coronary microvascular disease does not elicit myocardial fibrosis in this population. The examined parameters seem to provide independent information about myocardial and coronary disease.

KeywordsMicrovascular dysfunction Women Angina pectoris T1 mapping Coronary flow velocity reserve Cardiovascular magnetic resonance Doppler echocardiography Positron emission tomography Diffuse fibrosis Extracellular volume AbbreviationsAHAAmerican Heart Association

BMIBody mass index

BPBlood pressure

CADCoronary artery disease

CAGCoronary angiography

CFVCoronary flow velocity

CFVRCoronary flow velocity reserve

CMDCoronary microvascular dysfunction

CMRCardiovascular magnetic resonance


ECVExtracellular volume

ESCEuropean Society of Cardiology

HRHeart rate

IQRInterquartile range

LADLeft anterior descending artery

LCXLeft circumflex artery

LVHLeft ventricular hypertrophy

MBFMyocardial blood flow

MBFRMyocardial blood flow reserve

PETPositron emission tomography

RCARight coronary artery

SDStandard deviation

TTDETransthoracic Doppler echocardiography

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Author: Naja Dam Mygind - Marie Mide Michelsen - Adam Pena - Abbas Ali Qayyum - Daria Frestad - Thomas Emil Christensen - Adam 


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