Percutaneous Coronary Intervention for Myocardial Infarction
with Left Ventricular Dysfunction
James D. Flaherty, MD,
a,
* Charles J. Davidson, MD,
a
and David P. Faxon, MD
b
Patients who have had a myocardial infarction (MI) are at high risk for developing
left ventricular dysfunction (LVD), which predisposes them to heart failure and is
associated with an increased mortality risk. Early coronary revascularization, either
with percutaneous coronary intervention or coronary artery bypass graft surgery,
plays an important role in the preservation and restoration of left ventricular function
after MI. This article discusses the effects of primary and nonemergent percutaneous
coronary revascularization procedures on survival, left ventricular function, and the
occurrence of complications, such as recurrent MI and stroke, compared with the
effects of thrombolytic therapy. In addition, this article describes rescue revascular-
ization procedures for patients who failed thrombolysis and those presenting rela-
tively late or with negative electrocardiographic findings. Advanced interventional
techniques, such as percutaneous ventricular assist devices and bioabsorbable stents,
are very promising and may potentially help improve the outcomes of post-MI
patients with LVD; however, the use of these techniques requires further
validation. © 2008 Elsevier Inc. All rights reserved. (Am J Cardiol 2008;102[suppl]:
38G– 41G)
Coronary artery disease (CAD) is the predominant cause of
left ventricular dysfunction (LVD). Most patients with LVD
attributable to CAD have had a myocardial infarction (MI).
LVD can occur as a consequence of an electrocardiographic
ST-segment elevation MI (STEMI) or a non-STEMI.
The degree of LVD after MI correlates directly with
mortality as well as with the risk of recurrent MI and heart
failure (HF).
1
The risk of post-MI HF and death is inversely
proportional to the left ventricular ejection fraction (LVEF).
2
However, a substantial proportion of patients who develop
post-MI HF have preserved systolic function.
3
Post-MI pa-
tients who develop HF have markedly increased early and late
mortality.
4
Early myocardial revascularization, either
with percutaneous coronary intervention (PCI) or coro-
nary artery bypass graft (CABG) surgery, plays an im-
portant role in the preservation and restoration of left
ventricular function after MI.
Primary Percutaneous Coronary Intervention
Early reperfusion of the infarct-related artery (IRA) during
STEMI, with intravenous thrombolytic therapy or primary
PCI, results in the recovery of left ventricular systolic func-
tion and improved early and long-term survival.
5,6
Random-
ized controlled trials have shown that primary PCI yields a
superior survival benefit compared with thrombolytic ther-
apy. A large registry experience from Sweden has shown
similar benefits in a real-world setting.
7
The superiority of
primary PCI over thrombolytic therapy is directly related to
improved patency of the IRA (90% vs 65%).
8
Primary PCI
also leads to a higher predischarge LVEF and reduced rates
of reinfarction, stroke, and HF.
8,9
The degree of left ven-
tricular functional recovery achieved with primary PCI is
inversely proportional to the time to reperfusion.
10
But even
when restoration of flow in the IRA occurs too late for
myocardial salvage, primary PCI can still prevent adverse
left ventricular remodeling.
10
The American College of Car-
diology/American Heart Association (ACC/AHA) guide-
lines recommend PCI over lytic therapy when reperfusion
can be done within 90 minutes of presentation.
11
However,
a recent large registry study suggests that improved survival
may still be realized with longer delays.
7
Cardiogenic shock in the setting of acute MI is usually a
result of severe left ventricular systolic dysfunction (LVSD)
and is associated with a very high rate of in-hospital mor-
tality.
12
In the SHould We Emergently Revascularize Oc-
cluded Coronaries for Cardiogenic ShocK (SHOCK) trial,
patients with acute MI and cardiogenic shock were randomized
to either an early revascularization strategy (within 6 hours of
randomization) or a medical stabilization strategy (including
63% thrombolysis, 86% intra-aortic balloon pump use, and
25% subsequent revascularization).
13
Among the patients who
received early revascularization, 55% underwent PCI and 38%
underwent CABG surgery. At 1 year, there was a 46.7%
a
Division of Cardiology, Department of Medicine, Feinberg School of
Medicine, Northwestern University, Chicago, Illinois, USA; and
b
Depart-
ment of Medicine, Harvard Medical School, Boston, Massachusetts, USA.
Statement of author disclosure: Please see the Author Disclosures
section at the end of this article.
*Address for reprints: James D. Flaherty, MD, Assistant Professor of
Medicine, Division of Cardiology, 251 East Huron Street, Galter 8-130,
Chicago, Illinois 60611.
E-mail address: j-flaherty2@md.northwestern.edu.
0002-9149/08/$ – see front matter © 2008 Elsevier Inc. All rights reserved. www.AJConline.org
doi:10.1016/j.amjcard.2008.06.009