Myocardial edema after ischemia/reperfusion is not stable and follows a bimodal pattern: imaging and histological tissue characterization

It is widely accepted that edema occurs early in the ischemic zone and persists in stable form for at least 1 week after myocardial ischemia/reperfusion. However, there are no longitudinal studies covering from very early (minutes) to late (1 week) reperfusion stages confirming this phenomenon. This...

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Published in:Journal of the American College of Cardiology 2015-02, Vol.65 (4), p.315-323
Main Authors: Fernández-Jiménez, Rodrigo, Sánchez-González, Javier, Agüero, Jaume, García-Prieto, Jaime, López-Martín, Gonzalo J, García-Ruiz, José M, Molina-Iracheta, Antonio, Rosselló, Xavier, Fernández-Friera, Leticia, Pizarro, Gonzalo, García-Álvarez, Ana, Dall'Armellina, Erica, Macaya, Carlos, Choudhury, Robin P, Fuster, Valentin, Ibáñez, Borja
Format: Article
Language:English
Subjects:
Animals
Disease Models, Animal
Edema - etiology
Edema - pathology
Magnetic Resonance Imaging
Male
Myocardial Reperfusion Injury - complications
Myocardial Reperfusion Injury - pathology
Myocardium - chemistry
Myocardium - pathology
Swine
Water - analysis
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Summary:It is widely accepted that edema occurs early in the ischemic zone and persists in stable form for at least 1 week after myocardial ischemia/reperfusion. However, there are no longitudinal studies covering from very early (minutes) to late (1 week) reperfusion stages confirming this phenomenon. This study sought to perform a comprehensive longitudinal imaging and histological characterization of the edematous reaction after experimental myocardial ischemia/reperfusion. The study population consisted of 25 instrumented Large-White pigs (30 kg to 40 kg). Closed-chest 40-min ischemia/reperfusion was performed in 20 pigs, which were sacrificed at 120 min (n = 5), 24 h (n = 5), 4 days (n = 5), and 7 days (n = 5) after reperfusion and processed for histological quantification of myocardial water content. Cardiac magnetic resonance (CMR) scans with T2-weighted short-tau inversion recovery and T2-mapping sequences were performed at every follow-up stage until sacrifice. Five additional pigs sacrificed after baseline CMR served as controls. In all pigs, reperfusion was associated with a significant increase in T2 relaxation times in the ischemic region. On 24-h CMR, ischemic myocardium T2 times returned to normal values (similar to those seen pre-infarction). Thereafter, ischemic myocardium-T2 times in CMR performed on days 4 and 7 after reperfusion progressively and systematically increased. On day 7 CMR, T2 relaxation times were as high as those observed at reperfusion. Myocardial water content analysis in the ischemic region showed a parallel bimodal pattern: 2 high water content peaks at reperfusion and at day 7, and a significant decrease at 24 h. Contrary to the accepted view, myocardial edema during the first week after ischemia/reperfusion follows a bimodal pattern. The initial wave appears abruptly upon reperfusion and dissipates at 24 h. Conversely, the deferred wave of edema appears progressively days after ischemia/reperfusion and is maximal around day 7 after reperfusion.
ISSN:1558-3597
DOI:10.1016/j.jacc.2014.11.004