What is the clinical evidence from this study?

Study design: RCT. Population: Acute myocardial infarction (n=44). Intervention: Late reperfusion vs. Non-reperfusion. Primary outcome: Improvements in ejection fraction and chord shortening in the infarct region from the acute phase to the chronic phase.

January 1, 2001Open Access

Late Reperfusion (6-24 Hours After Onset) Improves Left Ventricular Function in Patients With Acute Myocardial Infarction.

SMShoichi MiyamotoSakurabashi Watanabe Hospital YGYoichi GotoPreventive Cardiology MFMasatoshi FujitaUniversity of Fukui

Key Result

Late reperfusion 6-24 hours after symptom onset (achieving 91% chronic patency) significantly improved left ventricular ejection fraction compared to non-reperfusion in patients with AMI.

Study Design

Type

RCT (n=44)

Randomization

Randomized

Structured PICO

Does late reperfusion (6-24 hours after onset) improve left ventricular function in patients with acute myocardial infarction?

Population

44 patients with acute myocardial infarction (AMI) admitted 6-24 hours after symptom onset with total occlusion of the infarct-related artery (IRA), mean age 61 (range 39-80), 77% male (34 men, 10 women), based in Japan.

Intervention

Late reperfusion via intracoronary thrombolysis (tissue-type plasminogen activator 160,000 U/min, max 6,400,000 U) and/or percutaneous transluminal coronary angioplasty (PTCA), followed by continuous IV heparin and nitroglycerin for 24-72 hours.

Comparator

Non-reperfusion (no intervention applied to the occluded infarct-related artery). Both groups received initial IV heparin (two 5,000 U boluses).

Outcome

Improvement in left ventricular ejection fraction and chord shortening in the infarct region from the acute phase to the chronic phase (at mean 29 days follow-up), measured via left ventriculography.surrogate

Late reperfusion of an occluded infarct-related artery 6-24 hours after acute myocardial infarction onset significantly improves left ventricular global and regional function compared to persistent occlusion.

Abstract

The TAMI-6 trial has demonstrated that coronary reperfusion >6h after onset (ie, late reperfusion) in patients with acute myocardial infarction (AMI) does not improve left ventricular (LV) function during the chronic phase of infarction. However, the low patency rate (only 60%) of the infarct-related artery (IRA) during the chronic phase in the TAMI-6 trial raises a new hypothesis that late reperfusion with a higher patency rate may improve LV function during the chronic phase. Forty-four patients with AMI, who were admitted to hospital 6-24h after the symptom onset and in whom emergency coronary angiography revealed a total occlusion of the IRA, were randomly assigned to either the late reperfusion group (n=22) or the non-reperfusion group (n=22). The initial success rate of reperfusion therapy in the late reperfusion group was 86% and the chronic patency rate of the IRA was 91%. The improvements in ejection fraction and chord shortening in the infarct region from the acute phase to the chronic phase were significantly greater in the late reperfusion group than in the non-reperfusion group. Late reperfusion with a high patency rate of the IRA significantly improves LV global and regional function in patients with AMI.

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