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Myocardial Edema After Ischemia/Reperfusion Is Not Stable and Follows a Bimodal Pattern

2014; Elsevier BV; Volume: 65; Issue: 4 Linguagem: Inglês

10.1016/j.jacc.2014.11.004

1558-3597

Rodrigo Fernández‐Jiménez, Javier Sánchez‐Gonzalez, Jaume Agüero, Jaime García‐Prieto, Gonzalo J. López-Martín, José M. García‐Ruiz, Antonio Molina, Xavier Rosselló, Leticia Fernández‐Friera, Gonzalo Pizarro, Ana García‐Álvarez, Erica Dall’Armellina, Carlos Macaya, Robin P. Choudhury, Valentı́n Fuster, Borja Ibáñez,

Cardiac electrophysiology and arrhythmias

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.