Author + information
- Received November 13, 2017
- Revision received February 21, 2018
- Accepted February 22, 2018
- Published online May 6, 2019.
- Giovanni Luigi De Maria, MDa,b,
- Mohammad Alkhalil, BSc, MDa,
- Mathias Wolfrum, MDa,
- Gregor Fahrni, MDa,
- Alessandra Borlotti, PhDa,c,
- Lisa Gaughran, RNa,
- Sam Dawkins, MBBS, DPhila,
- Jeremy P. Langrish, MD, PhDa,
- Andrew J. Lucking, MD, PhDa,
- Robin P. Choudhury, DMc,d,
- Italo Porto, MD, PhDb,
- Filippo Crea, MDb,
- Erica Dall’Armellina, MD, DPhila,b,
- Keith M. Channon, MDa,
- Rajesh K. Kharbanda, MD, PhDa and
- Adrian P. Banning, MBBS, MDa,∗ ()
- aOxford Heart Centre, National Institute for Health Research Biomedical Research Centre, Oxford University Hospitals, Oxford, United Kingdom
- bAcute Vascular Imaging Centre, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
- cDivision of Cardiovascular Medicine, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
- dDepartment of Cardiology, Policlinico A. Gemelli, Università Cattolica del Sacro Cuore, Rome, Italy
- ↵∗Address for correspondence:
Prof. Adrian Banning, Oxford Heart Centre, Oxford University Hospitals, Headley Way, Oxford OX39DU, United Kingdom.
Objectives This study aimed to compare the value of the index of microcirculatory resistance (IMR) and microvascular obstruction (MVO) measured by cardiac magnetic resonance (CMR) in patients treated for and recovering from ST-segment elevation myocardial infarction.
Background IMR can identify patients with microvascular dysfunction acutely after primary percutaneous coronary intervention (pPCI), and a threshold of >40 has been shown to be associated with an adverse clinical outcome. Similarly, MVO is recognized as an adverse feature in patients with ST-segment elevation myocardial infarction. Even though both IMR and MVO reflect coronary microvascular status, the interaction between these 2 parameters is uncertain.
Methods A total of 110 patients treated with pPCI were included, and IMR was measured immediately at completion of pPCI. Infarct size (IS) as a percentage of left ventricular mass was quantified at 48 h (38.4 ± 12.0 h) and 6 months (194.0 ± 20.0 days) using CMR. MVO was identified and quantified at 48 h by CMR.
Results Overall, a discordance between IMR and MVO was observed in 36.7% of cases, with 31 patients having MVO and IMR ≤40. Compared with patients with MVO and IMR ≤40, patients with both MVO and IMR >40 had an 11.9-fold increased risk of final IS >25% at 6 months (p = 0.001). Patients with MVO and IMR ≤40 had a significantly smaller IS at 6 months (p = 0.001), with significant regression in IS over time (34.4% [interquartile range (IQR): 27.3% to 41.0%] vs. 22.3% [IQR: 16.0% to 30.0%]; p = 0.001).
Conclusions Discordant prognostic information was obtained from IMR and MVO in nearly one-third of cases; however, IMR can be helpful in grading the degree and severity of MVO.
- index of microcirculatory resistance
- microvascular obstruction
- primary percutaneous coronary intervention
- ST-segment elevation myocardial infarction
This study was supported by the British Heart Foundation (BHF) (grant CH/16/1/32013), BHF Centre of Research Excellence, Oxford (RG/13/1/30181), and the National Institute for Health Research Oxford Biomedical Research Centre. Dr. Porto has received consulting or speaker fees from Volcano and St. Jude. Prof. Banning has received an unrestricted institutional research grant from Boston Scientific; and speaker fees from Abbott Vascular and Boston Scientific. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
- Received November 13, 2017.
- Revision received February 21, 2018.
- Accepted February 22, 2018.
- 2019 American College of Cardiology Foundation
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