Myocardial reperfusion for acute myocardial infarction under an optimized antithrombotic medication: What can you expect in daily practice?

Highlights

• The major goal of reperfusion strategies in STEMI is to limit infarct size and improve outcomes

• The prompt restoration of coronary flow in STEMI is necessary but not sufficient to achieve effective myocardial reperfusion

• An optimal corrected TIMI Frame Count was obtained in only one patient out of three

• Microvascular reperfusion attested by complete ST resolution remained modest and found in 44% of cases

• No differences in myocardial reperfusion were found according to the different antithrombotic strategies used

Abstract

Aims

To assess both epicardiac macrovascular as well as microvascular and tissue reperfusion following different intravenous preadmission antithrombotic strategies prior primary PCI in STEMI patients.

Methods and results

Consecutive STEMI patients (n = 488) undergoing pPCI received prehospitally either bivalirudin (n = 179), bivalirudin and periprocedural GPIIb/IIIa inhibitors (GPI) (n = 109), heparin (n = 99) or heparin and periprocedural GPI (n = 101). Epicardial perfusion and microvascular perfusion were assessed by angiography (TIMI flow rate and corrected TIMI frame count [cTFC]) and by ECG (ST resolution [STR]).

TIMI 3 flow was restored at the end of the procedure in 85.2% of the cases; cTFC of ≤23 was obtained in 37.2% of cases and STR >70% in 42.5% of the cases. The rates of STR >70% and cTFC ≤23 were not different between the three groups. Multivariate analysis did not identify a predictive antithrombotic treatment to obtain either post-procedural TIMI 3 flow rate or a STR rate >70%.

TIMI 3 flow before procedure and delay first symptoms-balloon <6 h represented a positive predictive value of STR rate >70% and the LAD as infarct related artery a negative predictive value of STR rate of >70%.

Conclusion

The process of myocardial reperfusion by pPCI continues to be improved with earlier reperfusion but an optimal tissular reperfusion was present in only half of the cases.

Introduction

The major goal of reperfusion strategies in acute ST-segment elevation myocardial infarction (STEMI) is to limit infarct size and improve outcomes [1]. The prompt restoration of antegrade coronary blood flow in acute STEMI is necessary [1,2] but not sufficient to achieve effective myocardial reperfusion [3]. Indeed, myocardial recovery is often impaired by loss of microvascular integrity, diffuse myocardial oedema, or distal embolization into the microcirculation.

Last decade, antithrombotic treatments and manual thrombectomy were developed to reduce distal embolization during primary percutaneous coronary intervention (pPCI) to limit their adverse consequences. Several randomized clinical trials successively introduced GPIIbIIIa inhibitors (GPI) [4] and bivalirudin [5,6] as either an upstream or periprocedural treatment which proved efficient and safe for early administration in patients undergoing PCI. However, a number of changes have occurred in clinical practice since GPI and bivalirudin trials were conducted: (1) PCI via radial-artery access, which may reduce the risk of bleeding and vascular complications, has expanded (2) the use of manual thrombectomy and (3) new ADP receptor antagonists have been increasingly adopted.

The aim of our monocentric study was to assess the effect of different intravenous preadmission antithrombotic strategies on epicardial as well as myocardial reperfusion after primary PCI in a series of consecutive patients with STEMI in a contemporary, real world setting.