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Interventional Cardiology
Clinical Application of a Novel Self-expanding Coronary Stent in
Acute Myocardial Infarction
Christian Spaulding
Professor of Cardiology, Paris Descartes University and INSERM U 970, and Director, Catheterisation Laboratory, Cochin Hospital, Paris
Abstract
Acute myocardial infarction (AMI) is a severe coronary condition with potentially fatal consequences. Currently, the standard of care is to
perform thromboaspiration followed by stent implantation as part of percutaneous coronary intervention. However, due to the thrombus load
and vasoconstriction of the artery during the procedure, there is a tendency to underestimate vessel size, resulting in selection of a stent that
will be smaller than the artery after clot resolution and vasodilation. This potentially increases the risk of stent malapposition and subsequent
stent thrombosis. A novel self-expandable stent was recently developed; preliminary results from the APPOSITION I study demonstrate its
feasibility in the treatment of AMI and its ability to follow the enlargement of the artery with near perfect apposition. This self-expandable stent
may therefore become an important tool in the treatment of AMI.
Keywords
Self-expanding stent, acute myocardial infarction, percutaneous coronary intervention, stent malapposition, stent thrombosis, APPOSITION I
study, thromboaspiration
Disclosure: The author has no conflicts of interest to declare.
Received: 14 December 2009 Accepted: 23 December 2009
Correspondence: Christian Spaulding, Cardiology Department, Cochin Hospital, 27 rue du Faubourg Saint Jacques, Paris 75679, France.
E:
christian.spaulding@cch.ap-hop-paris.fr
Currently, the optimal treatment of acute myocardial infarction (AMI) Two major unresolved issues in the treatment of AMI include the
in patients presenting with ST-segment-elevation MI (STEMI) is to inability to restore blood flow to the heart during primary PCI and
perform a primary percutaneous coronary intervention (PCI) as the risk of stent thrombosis. The inability to restore blood flow to the
quickly as possible after onset of symptoms.
1,2
While this has become heart is a serious problem that is both potentially fatal and highly
the standard of care for treating AMI, several factors, including limited unpredictable. After a PCI, the risk of occurrence of stent thrombosis
availability of catheterisation laboratories in a specific region, may is greatest one to two weeks after the procedure. Stent thrombosis is
result in thrombolytic therapy being administered in place of PCI. associated with severe medical problems in the patient. Although the
Similarly, if the time to reach a medical centre with PCI capability is rate of presumed stent thrombosis remains low, with no significant
greater than 45 minutes, PCI is unlikely to be the first-line therapy. change since 1999,
4
it remains a serious cause for concern among
Performing thromboaspiration in the affected area to remove the clot physicians and patients alike.
prior to the implantation of a stent during PCI should be included as a
crucial step and has shown additional benefits in patient outcomes.
3
Stent Thrombosis and Stent Malapposition
The typical PCI routine should therefore be thromboaspiration Stent thrombosis can occur shortly after a PCI has been performed.
followed by stent implantation. The degree of stent thrombosis has been categorised as being acute
(0–24 hours), subacute (one to 30 days) or late (one to 12 months)
Substantial advances have been seen in medical technology in depending on how soon it occurs after the procedure.
5
In extremely
recent years, resulting in fewer complications associated with PCI rare cases, stent thrombosis can also occur over one year or even
procedures. A recent prospective study of data abstracted from 10 years after implantation.
6
The rate of stent thrombosis occurring
PCI report forms in New York State
4
showed a relatively low reported within one month of a PCI has been estimated to be 0.53%, with the
rate of 3.36% for any complications one month post-implantation over rate of presumed stent thrombosis cases being 0.82%.
4
Other
the eight years examined (1999–2006). In addition, when comparing estimates have placed the total incidence of stent thrombosis at
rates between early (1999–2002) and recent (2003–2006) periods, a 1–4%, occurring more frequently in patients with STEMI.
5
decline in complications was observed. A significant difference was
seen, whereby all complications were reduced from 4% in the early A recent study attempted to determine predictors of stent
period to 2.7% in the recent period (p<0.001). Although not thrombosis.
5
Evaluating only cases of STEMI, the study showed that
statistically significant, there was also a slight decline in death over 3.3% of the 3,203 eligible participants experienced stent thrombosis
the years.
4
However, despite these improvements, complications still within one year of implantation. Different factors were associated with
occur during and after PCI procedures. the different categories of stent thrombosis within the study. However,
© TOUCH BRIEFINGS 2009 71
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