Impact of point-of-care testing for CYP2C19 on platelet inhibition in patients with acute coronary syndrome and early dual antiplatelet therapy in the emergency setting

Aims

Only limited data exist about the role of point of care CYP2C19 testing in the acute setting in the early phase of acute coronary syndromes (ACS). Therefore, the present study was designed to investigate the impact of CYP2C19 loss-of–function point-of-care (POC) genotyping in patients presenting with acute coronary syndromes (ACS) and treated with dual antiplatelet therapy in the emergency setting.

Methods and Results

137 subjects with ACS scheduled for percutaneous coronary intervention were consecutively enrolled. Pre- and on-treatment platelet aggregation was assessed by multiple electrode aggregometry (MEA) after stimulation with adenosine diphosphate (ADP). Patients were loaded according to current guideline adherent indications and contraindications for use of P2Y₁₂ inhibitors in ACS. POC genotyping for CYP2C19*2 was performed in the emergency room after obtaining a buccal swab using the Spartan RX CYP2C19 system and obtaining patient’s informed consent. Prasugrel and ticagrelor treated patients had significantly lower PR compared to clopidogrel-treated patients. The benefits of prasugrel and ticagrelor compared to clopidogrel treated patients in terms of platelet inhibition were more pronounced in CYP2C19*2 carriers. Non-carriers showed similar inhibition regardless of particular P2Y₁₂ inhibitor treatment. Statistical analyses adjusting for factors associated with response (e.g. smoking) revealed that CYP2C19*2 allele carrier status and loading with different type of P2Y12 receptor blockers were significant predictors of on-treatment platelet reactivity in the early phase of ACS.

Conclusion

The results of this pilot study of treatment of patients in the early phase of ACS indicate that CYP2C19*2 POC genotyping might help to identify patients at risk with poor response to clopidogrel treatment, thereby benefiting from reloading and switching to alternative P2Y₁₂ receptor inhibition.     

Platelet activation in acute coronary syndrome and interventional therapy

Platelets play a critical role in formation of coronary thrombosis. An enhanced systemic platelet activation plays a significant role in the acute coronary syndrome. Despite better interventional techniques and better concomitant pharmacological therapy, the degree of platelet activation contributes significantly to prognosis and postinterventional event rate. Residual platelet activation after intervention is often associated with an enhanced initial platelet activation prior interventional treatment. An effective antiplatelet therapy is of utmost importance for the acute therapy and for secondary prevention in patients undergoing coronary interventions or with acute coronary syndrome. The efficacy of the antithrombotic therapy determines the long term prognosis in these patients.     

PET/CT and MR imaging biomarker of lipid-rich plaques using [Cu]-labeled scavenger receptor (CD68-Fc)

Continued uptake of modified low-density lipoproteins (LDL) by the scavenger receptor, CD68, of activated macrophages is a crucial process in the development of atherosclerotic plaques and leads to the formation of foam cells. Eight-weeks-old male Apolipoprotein E-deficient (ApoE^-/-) mice (n=6) were fed a high-fat diet for 12 weeks. C57BL/6J wildtype (WT) mice served as controls (n=6). Positron emission tomography (PET) with an acquisition time of 1800s (NanoPET/CT scanner; Mediso, Hungary & Bioscan, USA) was carried out 24h after intravenous tail vein administration of 50µl ⁶⁴Cu-CD68-Fc (~20-30µg labeled protein/mouse containing approximately 10-12MBq ⁶⁴Cu-CD68-Fc per mouse). Three days after PET/CT, all mice received an intravenous administration of 0.2 mmol/kg body weight of a gadolinium-based elastin-binding contrast agent to assess plaque burden and vessel wall remodeling. Two hours after injection, mice were imaged in a 3T clinical MR scanner (Philips Healthcare, Best, NL) using a dedicated single loop surface coil (23mm). Enhanced ⁶⁴Cu-CD68-Fc uptake was found in the aortic arches of ApoE^-/- compared to WT mice (ApoE^-/- mice:10.5±1.5Bq/cm³ vs. WT mice: 2.1±0.3Bq/cm³; P=0.002). Higher gadolinium-based elastin-binding contrast agent uptake was also detected in the aortic arch of ApoE^-/- compared to WT mice using R¹ maps (R¹=1.47±0.06 s^-1 vs. 0.92±0.05 s^-1; P <0.001). Radiolabeled scavenger receptor (⁶⁴Cu-CD68-Fc) may help to target foam cell rich plaques with high content of oxidized LDL. This novel imaging biomarker tool may have potential to identify unstable plaques and for risk stratification.     

Effect of Aspiration Thrombectomy on Microvascular Obstruction in NSTEMI Patients : The TATORT-NSTEMI Trial

Background

Aspiration thrombectomy in ST-segment elevation myocardial infarction is recommended by current guidelines based on several randomized trials. There are no trials assessing thrombectomy in non–ST-segment elevation myocardial infarction (NSTEMI) patients.

Objectives

The TATORT-NSTEMI (Thrombus Aspiration in Thrombus Containing Culprit Lesions in Non–ST-Elevation Myocardial Infarction) trial sought to assess the effect of aspiration thrombectomy on microvascular injury in patients with NSTEMI compared with standard percutaneous coronary intervention (PCI).

Methods

This prospective, controlled, multicenter study randomized 440 patients to adjunctive thrombectomy (n = 221) compared with conventional PCI (n = 219) in NSTEMI patients with thrombus-containing lesions. The primary endpoint of the extent of microvascular obstruction (MO) in the percentage of left ventricular mass (%LV) was assessed by cardiac magnetic resonance imaging within 4 days. Secondary endpoints included infarct size, myocardial salvage index, and angiographic parameters including myocardial blush grade and Thrombolysis In Myocardial Infarction flow grade. The combined clinical endpoint consisted of death, reinfarction, target vessel revascularization, and new congestive heart failure within 6 months.

Results

The primary endpoint of MO was not different between the thrombectomy and the standard PCI group with 2.0%LV (interquartile range [IQR]: 0.8 to 4.1) versus 1.4%LV (IQR: 0.7 to 2.6) (p = 0.17). Similarly, no significant differences were observed for infarct size (8.6%LV; IQR: 4.0 to 14.7 vs. 7.4%LV; IQR: 4.1 to 13.1; p = 0.46), myocardial salvage index (63.3; IQR: 35.4 to 87.2 vs. 65.6; IQR: 46.9 to 82.6; p = 0.45), or angiographic parameters such as blush grade (p = 0.63) and Thrombolysis In Myocardial Infarction flow grade (p = 0.66). Clinical follow-up at 6 months revealed no differences in the combined clinical endpoints (p = 0.22).

Conclusions

Aspiration thrombectomy in conjunction with PCI in NSTEMI with a thrombus-containing lesion does not lead to a reduction in MO. (Thrombus Aspiration in Thrombus Containing Culprit Lesions in Non-ST-Elevation Myocardial Infarction [TATORT-NSTEMI]; NCT01612312).     

Interobserver variability,detection rate,and lesion patterns of 68Ga-PSMA-11-PET/CT in early-stage biochemical recurrence of prostate cancer after radical prostatectomy

European Journal of Nuclear Medicine and Molecular Imaging - 68Ga-PSMA-11-PET/CT is increasingly used in early-stage biochemical recurrence of prostate cancer to detect potential lesions for an...     

Preserved bioactivity and tunable release of a SDF1-GPVI bi-specific protein using photo-crosslinked PEGda hydrogels

Chemokine-induced stem cell recruitment is a promising strategy for post myocardial infarction treatment. Injection of stromal cell-derived factor 1 (SDF1) has been shown to attract bone marrow-derived progenitor cells (BMPCs) from the blood that have the potential to differentiate into cardiovascular cells, which support angiogenesis, enabling the improvement of myocardial function. SDF1-GPVI bi-specific protein contains a glycoprotein VI (GPVI)-domain that serves as an anchor for collagen type I (Col I) and III, which are exposed in the wall of injured vasculature. In this study, we generated a cytocompatible hydrogel via photo-crosslinking of poly(ethylene glycol) diacrylate that serves as a reservoir for SDF1-GPVI. Controlled and sustained release of SDF1-GPVI was demonstrated over a period of 7 days. Release features were modifiable depending on the degree of the crosslinking density. Functionality of the GPVI-domain was investigated using a GPVI-binding ELISA to Col I. Activity of the SDF1-domain was tested for its CXCR4 binding potential. Preserved functionality of SDF1-GPVI bi-specific protein after photo-crosslinking and controllable release was successfully demonstrated in vitro supporting the implementation of this drug delivery system as a powerful tool for therapeutic protein delivery in the treatment of cardiovascular ischemic disease.