Prehospital high-dose tirofiban in patients undergoing primary percutaneous intervention. The AGIR-2 study

Cluster analysis of clinical, angiographic, and laboratory parameters in patients with ST-segment elevation myocardial infarction

INTRODUCTION

ST-segment elevation myocardial infarction (STEMI) represents the most harmful clinical manifestation of coronary artery disease. Risk assessment plays a beneficial role in determining both the treatment approach and the appropriate time for discharge. Hierarchical agglomerative clustering (HAC), a machine learning algorithm, is an innovative approach employed for the categorization of patients with comparable clinical and laboratory features. The aim of the present study was to investigate the role of HAC in categorizing STEMI patients and to compare the results of these patients.

METHODS

A total of 3205 patients who were diagnosed with STEMI at the university hospital emergency clinic between 2015 and 2023 were included in the study. The patients were divided into 2 different phenotypic disease clusters using the HAC method, and their outcomes were compared.

RESULTS

In the present study, a total of 3205 STEMI patients were included; 2731 patients were in cluster 1, and 474 patients were in cluster 2. Mortality was observed in 147 (5.4%) patients in cluster 1 and 108 (23%) patients in cluster 2 (chi-square P value < 0.01). Survival analysis revealed that patients in cluster 2 had a significantly greater risk of death than patients in cluster 1 did (log-rank P < 0.001). After adjustment for age and sex in the Cox proportional hazards model, cluster 2 exhibited a notably greater risk of death than did cluster 1 (HR = 3.51, 95% CI = 2.71-4.54; P < 0.001).

CONCLUSION

Our study showed that the HAC method may be a potential tool for predicting one-month mortality in STEMI patients.

Impact of age on pre-procedural TIMI flow in STEMI patients undergoing primary percutaneous coronary intervention

BACKGROUND

Advanced age is a major determinant of impaired prognosis among patients with ST-segment elevation myocardial infarction (STEMI). However, the mechanisms associated with suboptimal reperfusion and enhanced complications are still largely undefined. The aim of the present study was to assess the impact of age on the angiographic findings and the procedural results of primary percutaneous coronary intervention (pPCI) in patients with STEMI.

METHODS

A consecutive cohort of patients admitted for STEMI treated with pPCI were included. Infarct-related artery (IRA) patency was defined for preprocedural TIMI flow 3.

RESULTS

We included 520 patients, divided according to age tertiles (<61; 61-72; ≥73). Elderly patients were more often females, with hypertension, renal failure, prior myocardial infarction or PCI, with lower rates of smoking history, haemoglobin, leukocytes and cholesterol (P < 0.001), lower ejection fraction (P = 0.02), higher use of renin angiotensin system inhibitors, statins, ASA, calcium antagonists, diuretics and beta blockers. At angiography, for the IRA, percentage of thrombus (P = 0.02) and stenosis (P = 0.01), direct stenting (P = 0.02) and glycoprotein IIb-IIIa inhibitors (P = 0.04) inversely related with age, but for higher restenosis (P = 0.04). IRA patency was more common in patients aged ≥73 years (27.9% vs. 32.3% vs. 41.1%, P = 0.01). The impact of age on preprocedural TIMI flow was confirmed at multivariate analysis [adjusted odds ratio (95% confidence interval) = 0.68 (0.47-0.98), P = 0.04].

CONCLUSION

The present study shows that among STEMI patients undergoing primary PCI, more advanced age represents an independent predictor of preprocedural IRA patency. Future studies will define the implications on procedural results and long-term prognosis.

Antiplatelet Agents in Acute ST Elevation Myocardial Infarction

Platelet aggregation and thrombus formation represent the basic mechanism for clinical, electrocardiographic, and biomarker changes consistent with acute coronary syndrome. Various oral and intravenous formulations of platelet function inhibitors have been developed to help decrease platelet aggregation due to acute atherosclerotic plaque rupture. In this article, we review the various mechanisms, pharmacokinetics/pharmacodynamics, and the key clinical trials related to the platelet inhibitors that form the basis for current recommendations of their use in the ST elevation myocardial infarction guidelines by the American College of Cardiology/American Heart Association.

Sonothrombolysis in the ambulance for ST-elevation myocardial infarction: rationale and protocol

Background

Treatment of ST-elevation myocardial infarction (STEMI) has improved over the years. Current challenges in the management of STEMI are achievement of early reperfusion and the prevention of microvascular injury. Sonothrombolysis has emerged as a potential treatment for acute myocardial infarction, both for epicardial recanalisation as well as improving microvascular perfusion. This study aims to determine safety and feasibility of sonothrombolysis application in STEMI patients in the ambulance.

Methods

Ten patients with STEMI will be included and treated with sonothrombolysis in the ambulance during transfer to the PCI centre. Safety will be assessed by the occurrence of ventricular arrhythmias and shock during sonothrombolysis intervention. Feasibility will be assessed by the extent of protocol completion and myocardial visibility. Efficacy will be determined by angiographic patency rate, ST-elevation resolution, infarct size and left ventricular volumes, and function measured with cardiovascular magnetic resonance imaging, and contrast and strain echocardiography. A comparison will be made with matched controls using an existing STEMI database.

Discussion

Sonothrombolysis is a novel technique for the treatment of cardiovascular thromboembolic disease. The first clinical trials on its use for STEMI have demonstrated promising results. This study will be the first to examine the feasibility of in-ambulance sonothrombolysis for STEMI.

Trial registration

EU Clinical Trials Register (identifier: 2019-001883-31), registered 2020-02-25.

Antithrombotic therapy before, during and after emergency angioplasty for ST elevation myocardial infarction

The first three hours after symptom onset hold the maximum potential for myocardial reperfusion and salvage in ST-elevation myocardial infarction (STEMI) patients. During this period timely primary percutaneous coronary intervention (PPCI) or, when PPCI is not promptly feasible, pre-hospital administration of fibrinolyis or a glycoprotein IIb/IIIa-inhibitor (GPI) have been shown to restore coronary patency and reperfusion and even result in myocardial infarction (MI) abortion. On the other hand, oral antiplatelet therapy may not yet guarantee sufficient platelet inhibition. Patients presenting after this golden time have less, if any, benefit from an aggressive antithrombotic treatment prior to PPCI. Antithrombotic treatment during primary angioplasty should be tailored on the basis of the coronary thrombotic burden, vascular approach and the patient's risk of bleeding complications. A GPI-based approach may be favourable in patients presenting early with large MI and high thrombus burden, whereas a bivalirudin-based approach without GPI may be preferred in patients with higher bleeding risk. There are no data to support the use of GPI in bailout conditions. The powerful oral P2Y₁₂ inhibitors, prasugrel and ticagrelor, have been clearly shown to prevent stent thrombosis and recurrent ischaemic events after emergency percutaneous coronary intervention in STEMI patients. Open issues remaining are the treatment of patients with high bleeding risk, such as the elderly and those requiring anticoagulation, as well as the duration of dual antiplatelet therapy after STEMI.

Pre-PCI angiographic TIMI flow in the culprit coronary artery influences infarct size and microvascular obstruction in STEMI patients

OBJECTIVE

The influence of initial-thrombolysis in myocardial infarction (i-TIMI) coronary flow in the culprit coronary artery on myocardial infarct and microvascular obstruction (MVO) size is unclear. We assessed the impact on infarct size of i-TIMI flow in the culprit coronary artery, as well as on MVO incidence and size, by contrast-enhanced cardiac magnetic resonance (ce-CMR).

METHODS

In a prospective, multicenter study, pre-percutaneous coronary intervention (PCI) coronary occlusion was defined by an i-TIMI flow ≤1, and patency was defined by an i-TIMI flow ≥2. Infarct size, as well as MVO presence and size, were measured on ce-CMR 72h after admission.

RESULTS

A total of 140 patients presenting with ST-elevated myocardial infarction referred for primary PCI were included. There was no significant difference in final post-PCI TIMI flow between the groups (2.95±0.02 vs. 2.97±0.02, respectively; p=0.44). In the i-TIMI flow ≤1 group, infarct size was significantly larger (32±17g vs. 21±17g, respectively; p=0.002), MVO was significantly more frequent (74% vs. 53%, respectively; p=0.012), and MVO size was significantly larger [1.3 IQR (0; 7.1) vs. 0 IQR (0; 1.6)], compared to in the i-TIMI ≥2 patient group.

CONCLUSION

Initial angiographic TIMI flow in the culprit coronary artery prior to any PCI predicted final infarct size and MVO size: the better was the i-TIMI flow, the smaller were the infarct and MVO size.

Recent advances in the diagnosis and treatment of acute myocardial infarction

The Third Universal Definition of Myocardial Infarction (MI) requires cardiac myocyte necrosis with an increase and/or a decrease in a patient’s plasma of cardiac troponin (cTn) with at least one cTn measurement greater than the 99^th percentile of the upper normal reference limit during: (1) symptoms of myocardial ischemia; (2) new significant electrocardiogram (ECG) ST-segment/T-wave changes or left bundle branch block; (3) the development of pathological ECG Q waves; (4) new loss of viable myocardium or regional wall motion abnormality identified by an imaging procedure; or (5) identification of intracoronary thrombus by angiography or autopsy. Myocardial infarction, when diagnosed, is now classified into five types. Detection of a rise and a fall of troponin are essential to the diagnosis of acute MI. However, high sensitivity troponin assays can increase the sensitivity but decrease the specificity of MI diagnosis. The ECG remains a cornerstone in the diagnosis of MI and should be frequently repeated, especially if the initial ECG is not diagnostic of MI.

There have been significant advances in adjunctive pharmacotherapy, procedural techniques and stent technology in the treatment of patients with MIs. The routine use of antiplatelet agents such as clopidogrel, prasugrel or ticagrelor, in addition to aspirin, reduces patient morbidity and mortality. Percutaneous coronary intervention (PCI) in a timely manner is the primary treatment of patients with acute ST segment elevation MI. Drug eluting coronary stents are safe and beneficial with primary coronary intervention. Treatment with direct thrombin inhibitors during PCI is non-inferior to unfractionated heparin and glycoprotein IIb/IIIa receptor antagonists and is associated with a significant reduction in bleeding. The intra-coronary use of a glycoprotein IIb/IIIa antagonist can reduce infarct size. Pre- and post-conditioning techniques can provide additional cardioprotection. However, the incidence and mortality due to MI continues to be high despite all these recent advances. The initial ten year experience with autologous human bone marrow mononuclear cells (BMCs) in patients with MI showed modest but significant increases in left ventricular (LV) ejection fraction, decreases in LV end-systolic volume and reductions in MI size. These studies established that the intramyocardial or intracoronary administration of stem cells is safe. However, many of these studies consisted of small numbers of patients who were not randomized to BMCs or placebo. The recent LateTime, Time, and Swiss Multicenter Trials in patients with MI did not demonstrate significant improvement in patient LV ejection fraction with BMCs in comparison with placebo. Possible explanations include the early use of PCI in these patients, heterogeneous BMC populations which died prematurely from patients with chronic ischemic disease, red blood cell contamination which decreases BMC renewal, and heparin which decreases BMC migration. In contrast, cardiac stem cells from the right atrial appendage and ventricular septum and apex in the SCIPIO and CADUCEUS Trials appear to reduce patient MI size and increase viable myocardium. Additional clinical studies with cardiac stem cells are in progress.

The effects of tirofiban infusion on clinical and angiographic outcomes of patients with STEMI undergoing primary PCI

Objective:

The present study was designed to determine the effects of tirofiban (Tiro) infusion on angiographic measures, ST-segment resolution, and clinical outcomes in patients with STEMI undergoing PCI. Glycoprotein (GP) IIb/IIIa inhibitors are beneficial in ST-segment elevation myocardial infarction (STEMI) patients undergoing percutaneous coronary intervention (PCI), while the most effective timing of administration is still under investigation.

Methods:

A total of 1242 patients (83.0% males, mean (standard deviation; SD) age: 54.7 (10.9) years) with STEMI who underwent primary PCI were included in this retrospective non-randomized study in four groups, composed of no tirofiban infusion [Tiro (-); n=248], tirofiban infusion before PCI (pre-Tiro; n=720), tirofiban infusion during PCI (peri-Tiro; n=50), and tirofiban infusion after PCI (post-Tiro; n=224). In all Tiro (+) patients, bolus administration of Tiro (10 pg/kg) was followed by infusion (0.15 pg/kg/min) for a mean (SD) duration of 22.4±6.8 hours.

Results:

The pre-PCI Tiro group was associated with the highest percentage of patients with TIMI 3 flow (99.4%; p<0.001), the lowest corrected TIMI frame count [21(18-23.4); p<0.001], the highest percentage of patients with >75% ST-segment resolution (78.1%; p<0.001), and the lowest rate of in-hospital sudden cardiac death and in-hospital all-cause mortality (3.2%, p<0.05, 3.3%, p=0.01). Major bleeding was reported in 18 (1.8%) patients who received tirofiban.

Conclusion:

Use of standard-dose bolus tirofiban in addition to aspirin, high-dose clopidogrel, and unfractionated heparin prior to primary PCI significantly improves myocardial reperfusion, ST-segment resolution, in-hospital mortality rate, and in-hospital sudden cardiac death in patients with STEMI with no increased risk of major bleeding.

Efficacy of pre-hospital use of glycoprotein IIb/IIIa inhibitors in ST-segment elevation myocardial infarction before mechanical reperfusion in a rapid-transfer network (from the Acute Myocardial Infarction Registry of Brittany)

Previous studies investigating prehospital use of glycoprotein IIb/IIIa inhibitors (GPIs) in patients with ST-segment elevation myocardial infarction reached conflicting conclusions. The benefit of this strategy in addition to in-ambulance loading of dual-antiplatelet therapy remains controversial. The aim of this study was to analyze data from a prospective registry of patients with ST-segment elevation myocardial infarctions admitted <24 hours after symptom onset (July 2006 to May 2012). A total of 2,052 patients managed in a physician-staffed mobile intensive care unit (MICU)<12 hours after symptom onset and scheduled for primary percutaneous coronary intervention (PPCI) were retrospectively included. Patients who received GPIs in the MICU were compared with those who did not. The primary end point was infarct-related artery patency, defined as pre-PPCI Thrombolysis In Myocardial Infarction (TIMI) flow grade 3. GPIs were administered in the MICU to 737 patients (36%), including 430<2 hours after symptom onset, and 1,315 patients (64%) did not received prehospital GPIs. Pre-PPCI TIMI flow grade 3 rate was lower in patients treated in the MICU (17.2% vs 21.3%, p=0.03) because of patients treated >2 hours after symptom onset, of whom only 12.7% reached the primary end point. There was no significant difference between groups in the rate of in-hospital major adverse cardiac events. In conclusion, prehospital GPI use in patients with ST-segment elevation myocardial infarctions<12 hours after symptom onset scheduled for PPCI neither improved pre-PPCI infarct-related artery patency nor reduced in-hospital major adverse cardiac events.

Effect of Early Treatment With Tirofiban on Initial TIMI Grade 3 Flow of Patients With ST Elevation Myocardial Infarction

Background:

Before primary percutaneous coronary intervention (PCI) in patients with ST elevation myocardial infarction (STEMI), it is not clear whether a routine early administration of glycoprotein IIb/IIIa inhibitors in the emergency ward is beneficial or their administration in selected cases in the catheterization laboratory.

Objectives:

The present randomized clinical trial sought to investigate whether an earlier administration of Tirofiban could exert any impact on TIMI grade 3 flows and ST resolution in the electrocardiography of patients with STEMI before primary PCI.

Materials and Methods:

Patients with STEMI within twelve hours of symptom commencement were included if primary PCI was planned to be performed within ninety minutes of admission and excluded if they had contraindications for Tirofiban. Seventy patients were randomized to receive 25 μg/kg of bolus Tirofiban early in the emergency ward (the early Tirofiban group) in three minutes and 70 did not receive Tirofiban (the control group). The primary endpoint of the study was a Thrombolysis in Myocardial Infarction (TIMI) grade 3 flows on the initial angiogram. The study is registered as IRCT201105126463N1 in: www.irct.ir.

Results:

The study population had a mean age of 57.17 ± 10.09 years and included 79.3 % males. TIMI grade 3 flow was seen in 15 (21.4 %) patients of the Tirofiban group and 7 (10 %) of the control group (P = 0.06, odds ratio = 0.407, and 95 % confidence interval = 0.155-1.072). Complete ST resolution was seen in 30 (42.9 %) patients of the Tirofiban group and 34 (48.6 %) of the control group (P = 0.5).

Conclusion:

Although TIMI grade 3 flows trended to be higher in the patients who received early Tirofiban in the emergency ward, the difference did not constitute statistical significance and possible benefits, therefore, require further clarification.

Efficacy and safety of tirofiban-supported primary percutaneous coronary intervention in patients pretreated with 600 mg clopidogrel: results of propensity analysis using the Clinical Center of Serbia STEMI Register

BACKGROUND

Studies with platelet glycoprotein IIb/IIIa receptor inhibitors (GPIs) showed conflicting results in primary percutaneous coronary intervention (PPCI) patients who were pretreated with 600 mg clopidogrel. We sought to investigate the short- and long-term efficacy and safety of the periprocedural administration of tirofiban in a largest Serbian PPCI centre.

METHODS

We analysed 2995 consecutive PPCI patients enrolled in the Clinical Center of Serbia STEMI Register, between February 2007 and March 2012. All patients were pretreated with 600 mg clopidogrel and 300 mg aspirin. Major adverse cardiovascular events, comprising all-cause death, nonfatal infarction, nonfatal stroke, and ischaemia-driven target vessel revascularization, was the primary efficacy end point. TIMI major bleeding was the key safety end point.

RESULTS

Analyses drawn from the propensity-matched sample showed improved primary efficacy end point in the tirofiban group at 30-day (OR 0.72, 95% CI 0.53-0.97) and at 1-year (OR 0.74, 95% CI 0.57-0.96) follow up. Moreover, tirofiban group had a significantly lower 30-day all-cause mortality (secondary end point; OR 0.63, 95% CI 0.40-0.90), compared with patients who were not administered tirofiban. At 1 year, a trend towards a lower all-cause mortality was observed in the tirofiban group (OR 0.74, 95% CI 0.53-1.04). No differences were found with respect to the TIMI major bleeding during the follow-up period.

CONCLUSIONS

Tirofiban administered with PPCI, following 600 mg clopidogrel pretreatment, improved primary efficacy outcome at 30 days and at 1 year follow up without an increase in major bleeding.

Stenting in Acute STEMI Intervention

Stenting in acute myocardial infarction (AMI) has the benefits of achieving acute optimal angiographic results and correcting residual dissection to decrease the incidence of restenosis and reocclusion. Studies have shown that percutaneous transluminal coronary angioplasty for primary treatment after AMI is superior to thrombolytic therapy regarding the restoration of normal coronary blood flow. Coronary stenting improves initial success rates, decreases the incidence of abrupt closure, and is associated with a reduced rate of restenosis. In the presence of thrombus-containing lesions, coronary stenting constitutes an effective therapeutic strategy, either after failure of initial angioplasty or electively as the primary procedure.