Late coronary artery reperfusion: benefits and mechanisms.
In patients with acute myocardial infarction (AMI), coronary artery reperfusion beyond 4 to 6 h after the onset of symptoms is believed to have little or no effect on infarct size. However, benefits have been demonstrated even when reperfusion is performed late and without significant myocardial salvage. Late reperfusion prevents infarct expansion and left ventricular remodelling. The mechanism is multifactorial and partially related to salvage of small islets of still viable myocytes within the scar. Other benefits of late reperfusion are electrical stability and prevention of arrhythmias. The survival benefits of reperfusion are strongly dependent on the time after the onset of symptoms until treatment (better outcomes are obtained with earlier reperfusion). Based on the demonstration of a significant reduction in mortality, the current practice is to perform reperfusion up to 12 h after the onset of symptoms. The survival benefits of reperfusion performed 13 to 24 h after the onset of AMI are less certain; however, large AMIs, particularly anterior infarcts, have the maximum risk of remodelling. Thus, benefits of reperfusion on left ventricular remodelling, arrhythmogenicity and prevention of congestive heart failure justify reperfusion in this group of patients up to 24 h after the onset of symptoms.
Alhaddad
I A
IA
Bronx-Lebanon Hospital Center, Bronx, NY 10457, USA. alhaddad@pol.net
Kazimuddin
M
M
Brown
E J
EJ
D000818:Animals; D001145:Arrhythmias, Cardiac / Q000517:prevention & control; D005343:Fibrinolytic Agents / Q000627:therapeutic use; D006333:Heart Failure / Q000517:prevention & control; D006801:Humans; D009203:Myocardial Infarction / Q000188:drug therapy* / Q000401:mortality; D015425:Myocardial Reperfusion; D013300:Streptokinase / Q000627:therapeutic use; D013997:Time Factors; D010959:Tissue Plasminogen Activator / Q000627:therapeutic use; D016896:Treatment Outcome; D020257:Ventricular Remodeling
D005343:Fibrinolytic Agents; D013300:Streptokinase; D010959:Tissue Plasminogen Activator