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A comparison of the VASP index between patients with hemodynamically complicated and uncomplicated acute myocardial
Pavel Osmancik1, Radovan Jirmar, Katarina Hulikova
1Cardiocenter, Department of Cardiology, 3rd Medical School, Charles University and University Hospital Kralovske Vinohrady, Prague, Czech Republic. pavel.osmancik@gmail.com
Insights
Clopidogrel effectiveness is significantly reduced in critically-ill ST-segment elevation myocardial infarction (STEMI) patients with hemodynamic instability. This reduced efficacy, measured by the vasodilator-stimulated phosphoprotein (VASP) index, is likely due to factors like hypoperfusion and catecholamine use in unstable patients.
Area of Science:
- Cardiology
- Pharmacology
- Critical Care Medicine
Background:
- Critically-ill patients with ST-segment elevation myocardial infarction (STEMI) often have impaired gastrointestinal motility and liver function.
- Elevated catecholamine levels in critically-ill patients can also affect drug metabolism.
- Clopidogrel, an oral antiplatelet medication, may have reduced efficacy in these patients.
Purpose of the Study:
- To compare the effectiveness of clopidogrel in unstable STEMI patients requiring mechanical ventilation and catecholamine support versus stable STEMI patients.
- To assess laboratory-defined clopidogrel efficacy in different STEMI patient populations.
Main Methods:
- Two groups of 20 STEMI patients were studied: unstable (mechanically ventilated, on catecholamines) and stable (Killip I class).
- All patients underwent primary Percutaneous coronary intervention.
- Clopidogrel efficacy was evaluated by measuring the vasodilator-stimulated phosphoprotein (VASP) phosphorylation index at baseline, 4 hours, 24 hours, and 48 hours post-administration.
Main Results:
- The reduction in the VASP index was significantly less in unstable patients compared to stable patients (P < 0.001).
- Stable patients showed a significant decrease in VASP index by 34% at 24 hours.
- Unstable patients exhibited only a nonsignificant 8% decrease at 4 hours, with no further reduction observed.
Conclusions:
- Laboratory clopidogrel efficacy is diminished in STEMI patients with severe hemodynamic instability.
- Splanchnic and liver hypoperfusion, along with catecholamine use, are probable contributing factors to reduced clopidogrel effectiveness.
- Findings highlight potential challenges in antiplatelet therapy for critically-ill STEMI patients.
Introduction:
Critically-ill patients with ST-segment elevation myocardial infarction (STEMI) often present with insufficient gastroduodenal motility, liver hypoperfusion, and higher levels of circulating catecholamines. All of these factors can lead to reduced efficacy of clopidogrel, which is only available as a p.o. medication. The aim of the study was to compare clopidogrel effectiveness in unstable STEMI patients on mechanical ventilation with stable STEMI patients.
Materials And Methods:
Two groups of twenty patients with STEMI were enrolled. One group (unstable) consisted of 20 hemodynamically unstable patients on mechanical ventilation and catecholamine support. The other group (stable) consisted of 20 control patients (all patients with STEMI in Killip I class). All patients were treated by primary Percutaneous coronary intervention. Blood samples were drawn before (baseline), at 4h (4h+), 24h (1d+) and 2 days (2d+) after clopidogrel administration. Clopidogrel efficacy was assessed by measurement of vasodilator-stimulated phosphoprotein phosphorylation index.
Results:
The decrease in the vasodilator-stimulated phosphoprotein (VASP) index was substantially less in unstable patients compared with stable ones (ANOVA, P < 0.001). In stable patients, the VASP index decreased significantly by 20% at 4h+ and by 34% at 1d+, and remained significantly decreased by 31% at 2d+. In unstable patients, the VASP decreased nonsignificantly by 8% at 4h+, and no further decrease of VASP was present (-7% at 1d+, -11% at 2d+).
Conclusions:
Laboratory clopidogrel efficacy is lower in patients with MI and severe hemodynamic instability, probably due to splanchnic and liver hypoperfusion and catecholamine use.
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