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Coronary ischemia-reperfusion: role of nitric oxide and endothelin-1. A Review

are the basis of the current therapy for patients that suffer AMI (Figure 9).

Epicardialartery

myocardiu Norma
m l

NoR? eperfusión Thrombos
is TimelyReperfusión+

Prevention?of?
ReperfusiónInjury

Timely
Reperfusión

Figure 9. Schematic representation of a fragment of myocardium and an epicardial coronary artery under normal conditions and after
artery thrombosis with theoretical evolution of myocardium necrosis, non-exposed and exposed to reperfusion. RI=reperfusion injury.
Acute myocardial infarction is a dynamic process that frequently reaches the total extension of myocardium necrotized within 6 h after
initiating the artery occlusion.

Restauration of blood supply to the zone of the apparatus (128).
myocardium exposed previously to ischemia
(reperfusion) have beneficial effects and also adverse 2) Irreversible forms: a) microvascular plugging, first
effects in the myocardium, by which Braunwald and described by Krug et al. in 1966 (124). It may be a
Kloner wrote in 1985 that reperfusion by itself may be a consequence of capillary damage, endothelial and
“double-edge sword” (11). Reperfusion injury refers to cardiomyocyte cells swelling, micro-embolization of
myocardial, vascular, and/or electrophysiological material released from the atherosclerotic plaque, micro-
dysfunction that is induced by the restoration of blood thrombi, release of vasomotor and thrombogenic
flow to previously ischemic myocardial tissue. It is substances, and neutrophil cumulation (129, 130). These
recognized four forms of reperfusion injury, of which alterations may be related, at least in part, to the non-
two may be reversible and other two may be irreversible reflow phenomenon, and b) lethal myocardial
(111): reperfusion injury, characterized by death and apoptosis
of cardiomyocytes that were viable when reperfusion is
1) Reversible forms: a) cardiac arrhythmias, applied (131, 132 http://www. jci.
particularly ventricular arrhythmias, which usually self- org/articles/view/62874 - B2). Lethal myocardial
terminate or are easily treated (125), and b) myocardial reperfusion injury may account for up to 50% of the final
stunning, with contractile ventricular dysfunction as myocardial infarction size, and this type of injuries
consequence of alteration of myocardial contractile attenuates the benefits of myocardial reperfusion, and

@Real Academia Nacional de Farmacia. Spain 27