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Tirofiban is a glycoproteine (GP) IIb/IIIa receptor antagonist, which inhibits platelet-platelet aggregation and is a potential adjunctive antithrombotic treatment in patients with acute coronary syndromes (ACS) or high-risk percutaneous coronary interventions (PCI). It is administered intravenously as a bolus followed by continuous infusion. However, the dosage recommendations in the United States (US) and European Union (EU) differ considerably. Furthermore, in routine clinical practice, deviations from the recommendations may occur. The objective of the present study was to investigate the impact of different alterations on tirofiban plasma concentrations in US and EU administration regimens and to give suggestions for delay management in clinical practice. We therefore mathematically simulated the effects of different bolus-infusion delays and infusion interruptions in different scenarios according to the renal function. Here, we provide a systematic assessment of concentration patterns of tirofiban in the US versus EU dosage regimens. We show that differences between the two regimens have important effects on plasma drug levels. Furthermore, we demonstrate that deviations from the proper administration mode affect the concentration of tirofiban. Additionally, we calculated the optimal dosage of a second bolus to rapidly restore the initial concentration without causing overdosage. In conclusion, differences in tirofiban dosing regimens between the U.S and EU and potential infusion interruptions have important effects on drug levels that may impact on degrees of platelet inhibition and thus antithrombotic effects. Thus, the findings of our modelling studies may help to explain differences in clinical outcomes observed in previous clinical trials on tirofiban., (© 2022. The Author(s).)

Background and Purpose: The National Cardiovascular Data Registry (NCDR) risk scores for mortality, bleeding and acute kidney injury (AKI) are accurate outcome predictors of coronary catheterization procedures in North American populations. However, their application in German clinical practice remained elusive and we thus aimed to verify their use., Methods: NCDR scores for mortality, bleeding and AKI and corresponding clinical outcomes were retrospectively assessed in patients undergoing catheterization for ST-segment elevation myocardial infarction (STEMI), non-ST-segment elevation myocardial infarction (NSTEMI) or for elective coronary procedures at a German Heart Center from 2014 to 2017. Risk model performance was assessed using receiver-operating-characteristic curves (discrimination) and graphical analysis/logistic regression (calibration)., Results: A total of 1637 patients were included, procedures were performed for STEMI (565 patients, 34.5%), NSTEMI (572 patients, 34.9%) and elective purposes (500 patients, 30.5%); 6% (13% of STEMI and 5% of NSTEMI patients) presented in cardiogenic shock and 3% with resuscitated cardiac arrest. Radial access was used in 38% of procedures and cross-over was necessary in 5%; PCI was performed in 60% of procedures. In-hospital mortality was 6.3% (STEMI 14.5%; NSTEMI 3.7%; elective 0%) and major bleedings occurred in 5.6% (STEMI 10.6%; NSTEMI 5.4%; elective 0.2%); AKI was detected in 18.1% of patients (STEMI 23.7%; NSTEMI 27.3%; elective 1.4%), amounting to KDIGO stage I/II/III in 11.5%/3.5%/3.2%. NCDR risk models discriminated very well for mortality [AUC 0.93 with 95% confidence interval (CI) 0.91-0.95] and well for major bleeding (AUC 0.82, CI 0.78-0.86) and any AKI (AUC 0.83, CI 0.81-0.86). Discrimination in the subgroup of patients with PCI was comparable (mortality: AUC 0.90; major bleeding: AUC 0.78; any AKI: AUC 0.79). However, calibration showed considerable underestimation of mortality and AKI in high-risk patients, while major bleeding was consistently overestimated (Hosmer-Lemeshow p < 0.02 for all outcomes)., Conclusions: The NCDR risk models showed excellent performance in discriminating high-risk from low-risk patients in contemporary German interventional cardiology. Model calibration for adverse event probability prediction, however, is limited and demands recalibration, especially in high-risk patients.

Background: Prasugrel is more effective than clopidogrel in reducing platelet aggregation in acute coronary syndromes. Data available on prasugrel reloading in clopidogrel treated patients with high residual platelet reactivity (HRPR) i.e. poor responders, is limited., Objectives: To determine the effects of prasugrel loading on platelet function in patients on clopidogrel and high platelet reactivity undergoing percutaneous coronary intervention for acute coronary syndrome (ACS)., Patients: Patients with ACS on clopidogrel who were scheduled for PCI found to have a platelet reactivity ≥40 AUC with the Multiplate Analyzer, i.e. "poor responders" were randomised to prasugrel (60 mg loading and 10 mg maintenance dose) or clopidogrel (600 mg reloading and 150 mg maintenance dose). The primary outcome measure was proportion of patients with platelet reactivity <40 AUC 4 hours after loading with study medication, and also at one hour (secondary outcome). 44 patients were enrolled and the study was terminated early as clopidogrel use decreased sharply due to introduction of newer P2Y12 inhibitors., Results: At 4 hours after study medication 100% of patients treated with prasugrel compared to 91% of those treated with clopidogrel had platelet reactivity <40 AUC (p = 0.49), while at 1 hour the proportions were 95% and 64% respectively (p = 0.02). Mean platelet reactivity at 4 and 1 hours after study medication in prasugrel and clopidogrel groups respectively were 12 versus 22 (p = 0.005) and 19 versus 34 (p = 0.01) respectively., Conclusions: Routine platelet function testing identifies patients with high residual platelet reactivity ("poor responders") on clopidogrel. A strategy of prasugrel rather than clopidogrel reloading results in earlier and more sustained suppression of platelet reactivity. Future trials need to identify if this translates into clinical benefit., Trial Registration: ClinicalTrials.gov NCT01339026.

Short bowel syndrome after extensive surgical resection of the intestine is characterised by inadequate digestion and absorption of nutrients. Additional clinical problems include impaired absorption and metabolism of diverse drugs requiring individualised medical therapy or alternative treatments. We report a case of individualised dual antiplatelet therapy in a patient who underwent an extensive intestinal resection complicated by acute myocardial infarction requiring percutaneous coronary intervention and stent implantation. Genetic testing of CYP2C19 gene polymorphisms and platelet aggregation testing were used to assess responses to aspirin, clopidogrel, prasugrel and ticagrelor. Given its unique pharmacokinetics with good absorption and without need of metabolism to an active substance, ticagrelor appears to be the best for patients with short bowel syndrome who require dual antiplatelet therapy after coronary stent implantation., (2015 BMJ Publishing Group Ltd.)

Objectives: This study was designed to identify the multivariate effect of clinical risk factors on high on-treatment platelet reactivity (HPR) and 12 months major adverse events (MACE) under treatment with aspirin and clopidogrel in patients undergoing non-urgent percutaneous coronary intervention (PCI)., Methods: 739 consecutive patients with stable coronary artery disease (CAD) undergoing PCI were recruited. On-treatment platelet aggregation was tested by light transmittance aggregometry. Clinical risk factors and MACE during one-year follow-up were recorded. An independent population of 591 patients served as validation cohort., Results: Degree of on-treatment platelet aggregation was influenced by different clinical risk factors. In multivariate regression analysis older age, diabetes mellitus, elevated BMI, renal function and left ventricular ejection fraction were independent predictors of HPR. After weighing these variables according to their estimates in multivariate regression model, we developed a score to predict HPR in stable CAD patients undergoing elective PCI (PREDICT-STABLE Score, ranging 0-9). Patients with a high score were significantly more likely to develop MACE within one year of follow-up, 3.4% (score 0-3), 6.3% (score 4-6) and 10.3% (score 7-9); odds ratio 3.23, P=0.02 for score 7-9 vs. 0-3. This association was confirmed in the validation cohort., Conclusions: Variability of on-treatment platelet function and associated outcome is mainly influenced by clinical risk variables. Identification of high risk patients (e.g. with high PREDICT-STABLE score) might help to identify risk groups that benefit from more intensified antiplatelet regimen. Additional clinical risk factor assessment rather than isolated platelet function-guided approaches should be investigated in future to evaluate personalized antiplatelet therapy in stable CAD-patients.

Aims: Percutaneous coronary intervention (PCI)-related risks are increased among patients with left main disease (LMD). The aim was to evaluate the impact of antithrombotic therapy on outcomes after LMD PCI in a predominantly ACS population., Methods and Results: One hundred and seventy-seven patients undergoing LMD PCI were identified in a pooled dataset of 14,326 patients from three large randomised trials comparing treatment with heparin plus glycoprotein IIb/IIIa inhibitors (GPI) or bivalirudin alone, including the REPLACE-2, ACUITY and HORIZONS-AMI trials. Overall, net adverse clinical events (NACE) and non-CABG major bleedings at 30 days occurred more frequently in patients undergoing LMD PCI compared to the overall non-LMD PCI population (NACE: 19.8% vs. 10.6%, p≤0.001, major bleeding: 9.6% vs. 4.6%, p≤0.001). In the LMD group, bivalirudin was associated with significantly less non-CABG related major bleeding compared to heparin+GPI (4.5% versus 14.6%, relative risk [RR] 0.27, 95% CI: 0.09-0.83; p=0.013), while the composite ischaemic endpoint (death/MI/TVR) at 30 days was similar in the two groups (11.4% vs. 12.4%, p=0.513) resulting in a benefit on NACE for bivalirudin over heparin+GPI (14.8% vs. 24.7%; RR 0.53; p=0.039)., Conclusions: Among patients undergoing LMD PCI, the use of bivalirudin instead of heparin+GPI resulted in significantly less major bleeding and improved short-term net clinical outcome. Bivalirudin may be the preferred anticoagulation strategy in LMD PCI patients.