Author + information
- Received January 22, 2016
- Revision received February 9, 2016
- Accepted February 11, 2016
- Published online April 1, 2016.
- Marie Mide Michelsen, MDa,∗ (, )
- Naja Dam Mygind, MDb,
- Adam Pena, MDc,
- Ahmed Aziz, MDd,
- Daria Frestad, MDe,
- Nis Høst, MD, PhDa,
- Eva Prescott, MD, DMSca,
- Steering Committee of the iPOWER Study
- aDepartment of Cardiology, Bispebjerg Hospital, University of Copenhagen, Denmark
- bDepartment of Cardiology, Rigshospitalet, University of Copenhagen, Denmark
- cDepartment of Cardiology, Gentofte Hospital, University of Copenhagen, Denmark
- dDepartment of Cardiology, Odense University Hospital, Denmark
- eDepartment of Cardiology, Hvidovre Hospital, University of Copenhagen, Denmark
- ↵∗Reprint requests and correspondence:
Dr. Marie Mide Michelsen, Department of Cardiology, Building 67, Bispebjerg University Hospital, Bispebjerg Bakke 23, 2400 Copenhagen NV, Denmark.
Objectives This study investigated whether digital reactive hyperemia index (RHI) measured by digital pulse amplitude tonometry is a sensitive indicator of coronary microvascular dysfunction (CMD).
Background CMD is an early marker of cardiovascular disease. However, CMD is a complex diagnosis and consists of multiple abnormalities of the coronary circulation. Impaired RHI is a noninvasive measure of peripheral vascular dysfunction that can identify individuals with acetylcholine induced coronary vascular dysfunction. It is largely unknown whether there is also an association between RHI and the endothelial-independent aspect of CMD assessed as a coronary flow velocity reserve (CFVR).
Methods We included 339 women with chest pain suggestive of angina pectoris and a diagnostic invasive coronary angiogram without significant coronary artery stenosis (<50%). CFVR was measured by transthoracic pulsed wave Doppler echocardiography during dipyridamole infusion (0.84 mg/kg). RHI was assessed by digital pulse amplitude tonometry. Participants were categorized in 3 RHI and 3 CFVR groups. We examined the association between CFVR and RHI and the distribution of cardiovascular risk factors between the CFVR and RHI groups.
Results CFVR and RHI were successfully measured in 322 participants. Median CFVR was 2.3 (interquartile range: 2.0 to 2.8) and median RHI was 2.1 (interquartile range: 1.6 to 2.6). No correlation was found between CFVR and RHI (Spearman’s rho = –0.067, p = 0.23), and mean RHI did not differ between CFVR categories (p = 0.39). Participants with low CFVR were significantly older and had a significantly greater burden of hypertension, whereas participants with an impaired RHI had a higher body mass index and were more likely to have diabetes and be current smokers.
Conclusions RHI does not identify individuals with CMD assessed as impaired CFVR by dipyridamole stress echocardiography in women with no obstructive coronary artery disease. The two methods are likely to identify different aspects of vascular pathology, as indicated by the different association with cardiovascular risk factors.
- coronary flow reserve
- coronary microvascular function
- microvascular angina pectoris
- no obstructive coronary artery disease
- peripheral microvascular function
- reactive hyperemia index
The Danish Heart Foundation and the University of Copenhagen support this project financially. The 2 institutions have no involvement in the preparation, conduct or reporting of the study. Dr. Prescott is a member of the steering committee; the steering committee have read and approved the manuscript. All authors have reported that they have no relationships relevant to the contents of this paper to disclose.
- Received January 22, 2016.
- Revision received February 9, 2016.
- Accepted February 11, 2016.
- American College of Cardiology Foundation