Early versus delayed invasive strategy for intermediate- and high-risk acute coronary syndromes managed without P2Y12 receptor inhibitor pretreatment: Design and rationale of the EARLY randomized trial

According to recent literature, pretreatment with a P2Y₁₂ ADP receptor antagonist before coronary angiography appears no longer suitable in non-ST-segment elevation acute coronary syndrome (NSTE-ACS) due to an unfavorable risk-benefit ratio. Optimal delay of the invasive strategy in this specific context is unknown. We hypothesize that without P2Y₁₂ ADP receptor antagonist pretreatment, a very early invasive strategy may be beneficial. The EARLY trial (Early or Delayed Revascularization for Intermediate- and High-Risk Non-ST-Segment Elevation Acute Coronary Syndromes?) is a prospective, multicenter, randomized, controlled, open-label, 2-parallel-group study that plans to enroll 740 patients. Patients are eligible if the diagnosis of intermediate- or high-risk NSTE-ACS is made and an invasive strategy intended. Patients are randomized in a 1:1 ratio. In the control group, a delayed strategy is adopted, with the coronary angiography taking place between 12 and 72 hours after randomization. In the experimental group, a very early invasive strategy is performed within 2 hours. A loading dose of a P2Y₁₂ ADP receptor antagonist is given at the time of intervention in both groups. Recruitment began in September 2016 (n = 558 patients as of October 2017). The primary endpoint is the composite of cardiovascular death and recurrent ischemic events at 1 month. The EARLY trial aims to demonstrate the superiority of a very early invasive strategy compared with a delayed strategy in intermediate- and high-risk NSTE-ACS patients managed without P2Y₁₂ ADP receptor antagonist pretreatment.

High post-treatment platelet reactivity is associated with a high incidence of myonecrosis after stenting for non-ST elevation acute coronary syndromes

High post-treatment platelet reactivity (HPPR= adenosine diphosphate [ADP] 10 µM-induced platelet aggregation > 70%) identifies low responders to dual antiplatelet therapy with increased risk of recurrent cardiovascular (CV) events after stenting for non-ST elevation acute coronary syndromes (NSTEACS). This study was designed to compare the incidence of periprocedural myocardial infarction (MI) after stenting for NSTEACS patients between non-responders to dual antiplatelet therapy defined by HPPR and normo-responders. One hundred ninety NSTE-ACS consecutive patients undergoing coronary stenting were included in this prospective study. They received 250 mg aspirin and a 600 mg loading dose of clopidogrel at least 12 hours (h) before percutaneous coronary intervention (PCI). A single post-treatment blood sample was obtained before PCI to analyze maximal intensity of ADP-induced platelet aggregation, and troponin levels were analyzed before PCI, and 12 and 24 h after PCI. Troponin I was considered elevated if > 0.4 ng/ ml. HPPR was present in 22% of patients (n=42). Periprocedural MI occurred significantly more frequently in patients with HPPR than in the normo-responders (43% vs. 24%, p=0.014). After being correlated with recurrent ischemic events after stenting for NSTE-ACS, the HPPR seems to be also a marker of increased risk of periprocedural MI for NSTE-ACS patients.

Index of Microcirculatory Resistance: a new effective invasive tool to assess reperfusion after primary percutaneous coronary intervention for ST-segment elevation myocardial infarction

Assessment of myocardial reperfusion during primary percutaneous coronary intervention for ST-segment elevation myocardial infarction remains challenging. The pressure wire-derived Index of Microcirculatory Resistance (IMR) is a parameter reflecting the microcirculation status. We illustrated with two cases the accuracy of the IMR in the setting of STEMI to predict myocardial damage as well as LV function recovery.

Coronary wall characteristics after myocardial infarction without significant coronary angiographic lesion: an intravascular ultrasound study

AIM

Coronary of angiography may be normal or without significant lesion after myocardial infarction (MI) in about 10% of cases. Our aim was to evaluate intravascular ultrasound (IVUS) findings, mainly remodelling, in patients with normal or near normal angiography early after MI.

METHODS AND RESULTS

We prospectively included 17 patients, admitted for STEMI or non-STEMI with no lesion > 30% (QCA) on early coronary angiography. Culprit vessel was defined by evidence of a thrombus in a proximal segment, distal embolization or focal akinesia of the left ventricle. Negative remodelling (NR) was defined as a remodelling index (lesion/reference external elastic membrane cross sectional area [CSA]) < 0.95, no remodelling as between 0.95-1.05, and positive remodelling (PR) as > 1.05. IVUS could identify a short, single, minor, eccentric and hypoechogenic lesion in all patients, of proximal location in 76.4% cases. PR was observed in only 1 patient (5.9%).

CONCLUSION

A discrete lesion was observed in all patients with apparently normal arteries. Although previous reports have shown an association between PR and vulnerability, in our study PR was unusual. Our study supports the hypothesis that in some patients, vulnerability may appear very early in the natural history of coronary artery disease before any vessel remodelling.

Clopidogrel response: head-to-head comparison of different platelet assays to identify clopidogrel non responder patients after coronary stenting

OBJECTIVES

We investigated the agreement between different platelet tests to identify clopidogrel non response.

BACKGROUND

Biological definition of clopidogrel non response remains controversial. Different platelet tests have been linked with recurrent ischemic events and proposed for daily practice.

METHODS

We prospectively investigated the agreement of platelet tests to isolate clopidogrel non response in patients receiving high 150 mg clopidogrel maintenance dose after coronary stenting. Clopidogrel response was assessed with ADP-induced aggregation (ADP-Ag) (non response if >70%), Platelet reactivity index VASP (PRI VASP) (non response if >50%) and Verify Now Point-of-care assay (VN) (non response if PRU > 240 AU).

RESULTS

Seventy consecutive patients were included. The rates of non-responders were respectively: 13% (n = 9) with the ADP-Ag, 39% (n = 27) with the PRI VASP and 33% (n = 23) with the VN. We observed significant correlation between different platelet tests assessing clopidogrel response: r = 0.55 (p < 0.0001) for ADP-Ag and PRI VASP, r = 0.64 (p < 0.0001) for ADP-Ag and VN and r = 0.59 (p < 0.0001) for PRI VASP and VN. However, using the most common thresholds, the agreement between the difference tests was poor: 0.35 for ADP-Ag and PRI VASP, 0.36 for ADP-Ag and VN and 0.46 for PRI VASP and VN.

CONCLUSION

This study showed that assessment of platelet function inhibition by clopidogrel is highly test-specific. Indeed, our results demonstrated a poor agreement between different platelet assays and suggested that identification of clopidogrel non responders is test-dependent.

Predictive values of post-treatment adenosine diphosphate-induced aggregation and vasodilator-stimulated phosphoprotein index for stent thrombosis after acute coronary syndrome in clopidogrel-treated patients

A low response to clopidogrel has been associated with an increased risk of stent thrombosis. However, the definition of a nonresponse to clopidogrel remains controversial, and different tests have been used to assess the clopidogrel response. The present study was designed to assess the predictive value of adenosine diphosphate (ADP)-induced platelet aggregation (ADP-Ag) and the Platelet Reactivity Index of vasodilator-stimulated phosphoprotein for the occurrence of stent thrombosis in patients admitted for non-ST-elevation acute coronary syndrome undergoing percutaneous coronary intervention. A total of 598 consecutive patients with non-ST-elevation acute coronary syndrome undergoing coronary stenting were prospectively included. They received 600 mg of clopidogrel >or=12 hours before percutaneous coronary intervention. Acute or subacute definite or probable stent thrombosis occurred in 11 patients (1.8%). These patients had significantly greater ADP-Ag compared to patients free of stent thrombosis (68 +/- 14% vs 56 +/- 19%, p = 0.002) but only a trend toward a greater Platelet Reactivity Index of vasodilator-stimulated phosphoprotein (62 +/- 14% vs 53 +/- 23%, p = 0.19). The construction of receiver operating characteristic curves to examine the most predictive value of ADP-Ag for stent thrombosis gave a threshold of ADP-Ag of >67% to identify low responders. These patients were at a greater risk of stent thrombosis than the clopidogrel responders (4.3% vs 0.8%, odds ratio 5.8, 95% confidence interval 1.9 to 24.6, p = 0.003). In conclusion, in patients with non-ST-elevation acute coronary syndrome undergoing percutaneous coronary intervention, ADP-Ag is a good parameter to identify clopidogrel nonresponders who are at increased risk of stent thrombosis, with a cutoff value of ADP-Ag of >67%.

Predictive value of post-treatment platelet reactivity for occurrence of post-discharge bleeding after non-ST elevation acute coronary syndrome. Shifting from antiplatelet resistance to bleeding risk assessment?

AIMS

We assessed prospectively the association between occurrence of post-discharge non-CABG-related TIMI major and minor bleeding and post-treatment platelet reactivity in patients with non-ST elevation acute coronary syndrome (NSTE ACS).

METHODS AND RESULTS

Five hundred and ninety-seven consecutive patients admitted with NSTE ACS were prospectively included. Between hospital discharge and one month follow-up, we observed 16 (2.7%) non-CABG-related TIMI haemorrhagic complications including five (0.84%) major and 11 (1.8%) minor bleeds. Patients with bleeding had significantly lower post-treatment values of ADP-induced aggregation (43+/-14% versus. 56+/-19%, p=0.002) and platelet reactivity index VASP (43+/-14% versus 54+/-23%; p=0.04) and a trend for lower values of arachidonic acid-induced aggregation (2.4+/-5.4 versus 13+/-21; p=0.27). After stratification by quartiles based on post-treatment ADP-induced platelet aggregation, we identified patients in the first quartile as hyper-responders with very low post-treatment platelet reactivity, below <40%. The risk of TIMI major and minor bleeding was significantly higher in the first quartile of hyper-responders than in the others quartiles: 10 (6.6%) versus six (1.4%), p=0.001.

CONCLUSIONS

Our results suggest that assessment of post-treatment platelet reactivity might be used to detect hyper-responders to antiplatelet therapy with higher risk of non-CABG related bleeding and tailor antiplatelet therapy according to both ischaemic and bleeding risk.

Comparison of omeprazole and pantoprazole influence on a high 150-mg clopidogrel maintenance dose the PACA (Proton Pump Inhibitors And Clopidogrel Association) prospective randomized study

OBJECTIVES

This study sought to compare the effect of 2 proton pump inhibitors (PPIs) on platelet response to clopidogrel after coronary stenting for non-ST-segment elevation acute coronary syndrome (NSTE ACS).

BACKGROUND

Use of omeprazole has been reported to significantly decrease the clopidogrel antiplatelet effect because of cytochrome P450 interaction. Because all PPIs are metabolized by CYP2C19, but to a varying degree, we hypothesized that the reported negative omeprazole-clopidogrel drug interaction may not be caused by a class effect.

METHODS

A total of 104 patients undergoing coronary stenting for NSTE ACS were prospectively included and randomized to omeprazole or pantoprazole 20 mg. They received at discharge 75-mg aspirin and 150-mg clopidogrel. Platelet reactivity index (PRI) vasoactive stimulated phosphoprotein (VASP) was used to assess clopidogrel response and adenosine diphosphate (ADP)-induced aggregation for platelet reactivity (ADP-Ag).

RESULTS

After 1 month, patients receiving pantoprazole had a significantly better platelet response to clopidogrel as assessed with the PRI VASP: 36 +/- 20% versus 48 +/- 17% (p = 0.007). We identified more clopidogrel nonresponders in the omeprazole group than in the pantoprazole group: 44% versus 23% (p = 0.04), odds ratio: 2.6 (95% confidence interval: 1.2 to 6.2). Conversely, we did not observe any significant difference in platelet reactivity with ADP-Ag between the omeprazole and pantoprazole groups: 52 +/- 15% and 50 +/- 18%, respectively (p = 0.29).

CONCLUSIONS

The present findings suggest the preferential use of pantoprazole compared with omeprazole in patients receiving clopidogrel to avoid any potential negative interaction with CYP2C19.

[Renal artery stenosis after abdominal radiotherapy]

INTRODUCTION

Renal artery stenosis represented 1 to 5% of all arterial hypertensions and is the leading cause of secondary hypertension. Renovascular hypertension is more common among women less than 30 years old (fibrodysplasia, 33%) and men older than 50 years old (66% atherosclerosis). Other causes are rare, especially radiation-induced renal artery stenosis.

MATERIALS AND METHODS

We report the case of Mr. D., 49 years old, with severe high blood pressure (230/125 mmHg) seven years after abdominal radiotherapy for Hodgkin's disease. Echo-Doppler was performed and found a subocclusive right ostial renal artery stenosis probably radiation-induced taking into account the history of the patient. Renal angiography confirmed this diagnosis and percutaneous transluminal renal artery angioplasty was performed with a final acceptable result (residual stenosis<50%).

DISCUSSION

Radiation-induced renal artery stenosis is rare (0.5/1000 to 1%). Most of the cases are proximal and the median time from radiation to referral is nine years. Radiation-induced nephritis disease was often referred to occurrence high blood pressure after abdominal radiotherapy but various data shows that radiation can also cause damage to larger vessels sizes (such as renal arteries) induced by atherosclerosis radiation. Patients should be successful treated by percutaneous intervention, as demonstrated by Fakhouri et al. [Am J Kidney Dis 38 (2001) 302-309] in a study of 11 patients.

CONCLUSION

This case shows that radiation-induced renal artery stenosis may occur many years after initial treatment, and patients developing severe arterial hypertension after abdominal radiation should be investigated for renal artery stenosis.

Aspirin noncompliance is the major cause of "aspirin resistance" in patients undergoing coronary stenting

OBJECTIVES

We investigated the hypothesis that biological aspirin "resistance" may often be related to noncompliance in patients undergoing coronary stenting.

BACKGROUND

Premature discontinuation of antiplatelet therapy has been identified as a major risk factor for stent thrombosis and prior aspirin withdrawal has been associated with poor prognosis after acute coronary syndrome.

METHODS

We prospectively investigated the occurrence of aspirin noncompliance in 136 consecutive patients undergoing coronary stenting receiving aspirin 75 mg daily. We analyzed posttreatment maximal intensity of arachidonic acid-induced platelet aggregation (AA-Ag) during hospitalization after controlled intake of aspirin and 1 month after hospital discharge. After 1 month, all "nonresponders" received controlled aspirin 75 mg and assessment of response was repeated. Aspirin nonresponse was defined by AA-Ag >30%.

RESULTS

During inhospital period, the range of AA-Ag varied from 0% to 34% with a mean value of 7.5% +/- 10%, and 4 patients (3%) were classified as nonresponders. One month after discharge, AA-Ag of the population was significantly higher than during the hospital phase (15.3 +/- 23 vs 7.5 +/- 10%, P = .0004), and 19 patients (14%) were identified as nonresponders. After controlled administration of aspirin, all but one of these nonresponders became responders and were identified as patients with noncompliance rather than biological resistance.

CONCLUSION

Aspirin resistance is rare in compliant patients using methods that directly indicate the degree of platelet cyclooxygenase inhibition. More than 10% of patients receiving aspirin for coronary stenting are noncompliant for aspirin therapy during the first month after stenting. These results suggest a need for improved education of these patients.

Effect of increased aspirin dose after stenting in association with ClOpidogrel: the FIASCO randomized study

BACKGROUND

Increased doses of antiplatelet therapy have been proposed to overcome the variability of response. However, the chronic dose of aspirin after DES remains controversial.

METHODS AND RESULTS

We assessed in a prospective and randomized study the benefit of higher dose of aspirin, in association with clopidogrel, on aspirin response and non COX-specific platelet testing in patients receiving Drug Eluting Stent (DES) for stable angina pectoris. 50 consecutive patients receiving DES for stable angina pectoris were prospectively included. They received loading dose of 250 mg aspirin and 600 mg clopidogrel and antiplatelet response was assessed with Arachidonic Acid-induced aggregation (AA-Ag) and ADP-induced aggregation (ADP-Ag) for aspirin and clopidogrel response respectively. Patients were randomized to either 75 or 160 mg of aspirin with 150 mg clopidogrel and platelet testing were repeated one month after hospital discharge. The two groups (aspirin "75 mg" or "160 mg") had no difference for aspirin response: AA-Ag (5.2 +/- 1.7% vs 6 +/- 2%, p = 0.75) and non COX-specific pathway testing: ADP-Ag (47 +/- 3% vs 49 +/- 4%, p = 0.61).

CONCLUSION

The present study did not show any benefit of higher dose of aspirin neither on aspirin responsiveness, nor on inhibition of non COX-specific pathway. These data does not support use of higher dose than 75 mg of aspirin in association with clopidogrel in patients receiving DES, especially while higher doses have been associated with increased bleeding risk.

[Acute stent thrombosis due to resistance to clopidogrel ? A case report]

The authors report the case of a 65 year old man who presented with an acute coronary syndrome without ST elevation due to acute stent thrombosis 12 hours after implantation. Recent reports in the literature suggest the role of resistance to antiplatelet drugs in acute, subacute or late stent thrombosis. This patient was included in a protocol studying the response to antiplatelet drugs in patients undergoing coronary stenting and fulfilled the criteria of resistance to clopidogrel. This clinical case illustrates the possible role of "resistance" to antiplatelet drugs in stent thromboses.

High post-treatment platelet reactivity is associated with a high incidence of myonecrosis after stenting for non-ST elevation acute coronary syndromes

High post-treatment platelet reactivity (HPPR=adenosine diphosphate [ADP] 10 microM-induced platelet aggregation >70%) identifies low responders to dual antiplatelet therapy with increased risk of recurrent cardiovascular (CV) events after stenting for non-ST elevation acute coronary syndromes (NSTE-ACS). This study was designed to compare the incidence of periprocedural myocardial infarction (MI) after stenting for NSTE-ACS patients between non-responders to dual antiplatelet therapy defined by HPPR and normo-responders. One hundred ninety NSTE-ACS consecutive patients undergoing coronary stenting were included in this prospective study. They received 250 mg aspirin and a 600 mg loading dose of clopidogrel at least 12 hours (h) before percutaneous coronary intervention (PCI). A single post-treatment blood sample was obtained before PCI to analyze maximal intensity of ADP-induced platelet aggregation, and troponin levels were analyzed before PCI, and 12 and 24 h after PCI. Troponin I was considered elevated if >0.4 ng/ml. HPPR was present in 22% of patients (n=42). Periprocedural MI occurred significantly more frequently in patients with HPPR than in the normo-responders (43% vs. 24%, p=0.014). After being correlated with recurrent ischemic events after stenting for NSTE-ACS, the HPPR seems to be also a marker of increased risk of periprocedural MI for NSTE-ACS patients.

Secretion of phospholipase A2 induced by interactions of human platelets with monocytes

Phospholipase A2 (PLA2) activity was found and measured in the cell-free supernatants of human mononuclear cells (monocytes and lymphocytes) cultured with platelets for 48 h at 37 degrees C. The relative molecular mass of purified, calcium-dependent PLA2 was 14 kD. The amount of PLA2 in the supernatants correlated positively with the number of monocytes and platelets in the cultures. Electron microscopically, direct cell-to-cell interactions of monocytes and platelets were observed. Cultivation of suspensions of human mononuclear cells with platelets in serum-free medium was found to be an efficient way to produce and purify human secretable PLA2. In the release of secretable PLA2 in peripheral blood, the interactions between platelets and monocytes may play a considerable role.