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Coronary Stents
Innovative Stenting Approach for the Treatment of Thrombus-containing Lesions in
Acute Myocardial Infarction, Saphenous Vein Grafts and Acute Coronary Syndromes
a report by
Alexandre Abizaid
Chief, Coronary Interventions, Institute Dante Pazzanese de Cardiologia, São Paulo
In treating thrombus-loaded lesions through percutaneous coronary epicardium, which, in turn, can lead to necrosis. In addition, it can
intervention (PCI) in the settings of acute myocardial infarction (MI), cause a local inflammatory reaction at the blocked capillary due to
saphenous vein grafts (SVGs) and acute coronary syndromes (ACS), platelet aggregation, further aggravating the thrombogenic micro-
distal embolisation is a recognised prevalent occurrence, adversely environment. This chain of events is associated with suboptimal
affecting reperfusion and mortality rates. Thus, efficient management perfusion, larger infarct size, lower ejection fraction and higher
of embolisation, in terms of both reduced occurrence and minimised mortality rate.
1
The suboptimal perfusion ranges from lower epicardial
impact, could significantly improve the long-term success of PCI flow to an impaired flow (no re-flow) and occurs despite a full
procedures in acute settings of thrombus-containing lesions. This restoration of flow (TIMI 3) in the infarcted lesion through PCI.
2
The
article reviews the prevalence of distal embolisation in these settings, clinical implications of suboptimal perfusion have been shown to
its clinical implications and current strategies to prevent embolisation, significantly affect one-year mortality rates: 3.9% for a reduced
and presents a new, innovative and promising approach to treat perfusion and 4.5% for an absent perfusion, compared with 1.4% for
these lesions. a normal perfusion.
3
Distal Embolisation – Clinical Consequences A good indication for the high prevalence of embolisation in an acute
and Prevalence MI setting can be deduced from the exceptionally high rate of
There are two distinct sources within the affected artery for distal suboptimal perfusion – as high as 82%.
3
Direct evidence of the
embolisation: the thrombus occluding the artery and the plaque presence of embolised debris through its retrieval from various embolic
residing on the lesion’s lumen. Both thrombus and plaque protection devices points to more than 70% of cases.
4
embolisation often cause a shower of emboli to be released into
Management of Distal Embolisation – Current Strategies
Efficient management of
Distal Protective Devices
The devices that belong to this category are distal filter devices and
embolisation could significantly
distal occlusion devices. Although distal filter devices have proved to
improve the long-term success of be beneficial in SVGs,
5
they have failed to show clinical benefits in
percutaenous coronary intervention
acute MI.
6
Distal occlusion devices are based on a combination of an
inflation of a balloon distally to the lesion and concomitant aspiration
procedures in acute settings of
of debris released during the procedure. Although some clear benefits
thrombus-containing lesions.
have been proved in SVGs, these devices have failed to demonstrate
clear benefits in acute MI settings.
5
circulation, potentially leading to life-threatening intra- or post- Proximal Protective Devices
procedural complications. The trigger to the embolisation process Proximal protective devices are based on balloon occlusion proximal
is the result of mechanical interference with the thrombus or the to the lesion and aspiration of released debris during the procedure.
plaque by various devices during PCI, rendering the plaque layers Although this concept theoretically addresses the issues of distal
unstable and causing crushing and fragmentation. However, side branches and crossing the lesion, the clinical benefits remain to
embolisation may also be a consequence of a spontaneous rupture of be demonstrated.
7,8
plaque without any mechanical interference. In either case, it is clear
that the atherothrombotic burden of the patient is a major
determinant of embolisation.
Alexandre Abizaid is Chief of Coronary Interventions
at the Institute Dante Pazzanese de Cardiologia in
São Paulo, and a Visiting Professor of Medicine at
The clinical effects of distal embolisation range in severity from small
Columbia University Medical Center in New York City.
His areas of interest are drug-eluting stents and
MIs to cardiogenic shock and death. The outcome depends on the
intravascular ultrasound. Dr Abizaid completed medical
extent of embolisation, the size of the vascular bed involved and the school at the Federal University of Juiz de Fora in Brazil
haemodynamic status and associated co-morbidities of the patient.
and his fellowship at Washington Hospital Center in
Washington, DC.
Emboli released distally can block a capillary – part of the
microvasculature – leading to a potential ischaemia in part of the
© TOUCH BRIEFINGS 2008 37
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