Balázs Magyari

Justification of 150 mg clopidogrel in patients with high on-clopidogrel platelet reactivity.

Eur J Clin Invest 2012; 42 (4): 384–392

Comparison of aortic and carotid arterial stiffness parameters in patients with verified coronary artery disease

Arterial stiffness parameters are commonly used to determine the development of atherosclerotic disease. The independent predictive value of aortic stiffness has been demonstrated for coronary events.

Overlap of coronary disease and pulmonary arterial hypertension in systemic sclerosis

Objectives: Pulmonary arterial hypertension (PAH) is a common complication of systemic sclerosis (SSc). Symptoms of coronary artery disease (CAD) and PAH are closely related and cardiac catheterisation is needed to confirm their diagnosis. The aim of the present work was to investigate of the extent of overlap between CAD and PAH in patients with SSc. Methods: Based on non-invasive investigations, 20 patients out of 120 were suspected to have PAH (“suspected PAH” group). Another 10 patients showed signs of coronary disease (“suspected CAD” Group). In these 30 patients, right heart catheterisation and coronary angiography were performed, and the coronary flow reserve (CFR) was assessed by thermodilution technique. Results: In the “suspected PAH” and the “suspected CAD” groups, PAH was found in 12/20 and 2/10 cases, and coronary artery stenosis in 9/20 and 6/10 cases, respectively. Severely reduced CFR was revealed in 7/20 and 3/10 cases, respectively. Conclusions: PAH, CAD and reduced CFR all show a considerable overlap in symptomatic patients with SSc. The current non-invasive investigations are neither sensitive nor specific enough to make an appropriate distinction between these different disease manifestations. A more invasive approach, such as coronary angiography at the initial catheterisation, is required to properly characterise and treat the different forms of cardiac involvement in SSc.

Overview of large animal myocardial infarction models (review).

There are several experimental models for the in vivo investigation of myocardial infarction (MI) in small (mouse, rat) and large animals (dog, pig, sheep and baboons). The application of large animal models raises ethical concerns, the design of experiments needs longer follow-up times, requiring proper breeding and housing conditions, therefore resulting in higher cost, than in vitro or small animal studies. On the other hand, the relevance of large animal models is very important, since they mostly resemble to human physiological and pathophysiological processes. The first main difference among MI models is the method of induction (open or closed chest, e.g. surgical or catheter based); the second main difference is the presence or absence of reperfusion. The former (i.e. reperfused MI) allows the investigation of reperfusion injury and new catheter based techniques during percutaneous coronary interventions, while the latter (i.e. nonreperfused MI) serves as a traditional coronary occlusion model, to test the effects of new pharmacological agents and biological therapies, as cell therapy. The reperfused and nonreperfused myocardial infarction has different outcomes, regarding left ventricular function, remodelling, subsequent heart failure, aneurysm formation and mortality. Our aim was to review the literature and report our findings regarding experimental MI models, regarding the differences among species, methods, reproducibility and interpretation.

Mechanism of coronary flow reserve reduction in systemic sclerosis: insight from intracoronary pressure wire studies

OBJECTIVE Functional impairment of coronary microcirculation is thought to be a major pathway in the development of primary cardiac involvement in SSc; however, the underlying mechanism is not fully understood. We aimed to investigate the mechanisms of coronary flow reserve (CFR) reduction in patients with SSc. METHODS Seventeen SSc patients and 17 gender- and age-matched controls were enrolled. Coronary angiography and determination of coronary flow parameters including index of myocardial resistance (IMR) using intracoronary pressure wire at basal conditions and during vasodilator-induced maximal hyperaemia were performed. Transit times of repeated intracoronary saline injection were measured to evaluate the role of cold exposure. RESULTS SSc patients with decreased CFR had accelerated basal coronary flow velocity (P < 0.05), and their IMR in hyperaemia (IMR(hyp)) did not differ from either SSc patients with normal CFR or from the controls (P = 0.292 and P =  0.308). The coronary flow velocity of SSc patients correlated with the IMR at baseline (IMR(bas)) (r  = 0.56, P  = 0.019). Injection of room temperature saline did not provoke changes in coronary transit times. CONCLUSIONS The lack of decrease in the maximal vasodilatation response indicates that there is no irreversible functional damage at the level of the coronary arterioles. In patients with reduced CFR, the decreased basal IMR and higher velocity reflect compensatory vasodilatory mechanisms probably triggered by ischaemic signals deriving from abnormal myocardial microcirculation.

Evaluation of experimental myocardial infarction models via electromechanical mapping and magnetic resonance imaging.

The diagnostic characteristics of electromechanical mapping (EMM) were evaluated in porcine myocardial infarction (MI) models with the parallel application of cardiac magnetic resonance imaging (cMRI) from the aspect of different pathophysiology and localization. Balloon occlusion in the left anterior descending coronary artery (LAD balloon group) or coil deployment in the LAD (LAD coil group) or circumflex artery (Cx coil group) was applied percutaneously in 16 domestic pigs. Regional left ventricular viability data were captured via cMRI and EMM. The unipolar voltage (UV) value was significantly decreased in segments containing transmural and subendocardial late enhancement compared with viable segments in the LAD balloon, LAD coil, and Cx coil groups. Receiver operating characteristic analysis revealed area under the curve values of 0.809 and 0.691 in the LAD infarct territory, and 0.864 and 0.855 in the Cx infarct territory for the UV compared with cMRI viability results as transmural late enhancement or viable tissue and subendocardial late enhancement or viable tissue, respectively. In conclusion, the UV value detected the presence of scar tissue with differential transmural extent and which represented proper diagnostic features both in the reperfused and nonreperfused models. This data could provide additional benefit in the clinical use of EMM for diagnostic purposes.

Justification of 150mg clopidogrel in patients with high on-clopidogrel platelet reactivity

Eur J Clin Invest 2012; 42 (4): 384–392

Clinical outcomes in patients treated for coronary in-stent restenosis with drug-eluting balloons: Impact of high platelet reactivity

Background The impact of high platelet reactivity (HPR) on clinical outcomes after elective percutaneous coronary interventions (PCI) with drug-eluting balloons (DEB) due to in-stent restenosis (ISR) is unknown. Objective We sought to evaluate the prognostic importance of HPR together with conventional risk factors in patients treated with DEB. Methods Patients treated with DEB due to ISR were enrolled in a single-centre, prospective registry between October 2009 and March 2015. Only patients with recent myocardial infarction (MI) received prasugrel, others were treated with clopidogrel. HPR was defined as an ADP-test >46U with the Multiplate assay and no adjustments were done based on results. The primary endpoint of the study was a composite of cardiovascular mortality, MI, any revascularization or stroke during one-year follow-up. Results 194 stable angina patients were recruited of whom 90% were treated with clopidogrel. Clinical characteristics and procedural data were available for all patients; while platelet function testing was performed in 152 subjects of whom 32 (21%) had HPR. Patients with HPR had a higher risk for the primary endpoint (HR: 2.45; CI: 1.01–5.92; p = 0.03). The difference was primarily driven by a higher risk for revascularization and MI. According to the multivariate analysis, HPR remained a significant, independent predictor of the primary endpoint (HR: 2.88; CI: 1.02–8.14; p = 0.04), while total DEB length and statin treatment were other independent correlates of the primary outcome. Conclusion HPR was found to be an independent predictor of repeat revascularization and MI among elective patients with ISR undergoing PCI with DEB.

PrasugRel versus adjusted high-dose clopidogrel in patients with high on- clopidogrel platelet reactivity: the PECS-HPR randomized, multicenter study

background: Repeated loading doses (LD) of clopidogrel were shown to effectively overcome high on-clopidogrel platelet reactivity (HPR); however, comparison to potent P2Y12-inhibitors is lacking. We sought to compare the antiplatelet effect of high-dose clopidogrel versus prasugrel at both short- and long-term in acute coronary syndrome patients (ACS) with HPR. methods: ACS patients receiving 600 mg clopidogrel pretreatment were randomized to prasugrel or high-dose clopidogrel in a multicenter, controlled trial if platelet function testing revealed HPR (>46U) after PCI. In the prasugrel group, patients received an immediate 60-mg LD followed by 10 mg for three days. After day 3, patients were randomized to either standard (10 mg) or reduced (5 mg) maintenance doses up to 30 days. Patients randomized to high-dose clopidogrel received repeated loading doses of 600 mg clopidogrel based on controlled platelet function testing for three days, then were randomized to 75 mg or 150 mg maintenance doses for 30 days. ADP-induced platelet reactivity was measured with the Multiplate assay at day 0 (randomization), 1, 2, 3 and 25. Results: Between May 2011 and March 2013, 147 patients were randomized. Although baseline platelet reactivity did not differ between groups (p=0.22), prasugrel provided significantly more rapid and more potent platelet inhibition compared to repeated LD-s of clopidogrel through all three days after randomization (p<0.0001). During the maintenance phase, there was a dose-dependent increase in platelet reactivity from prasugrel 10 mg to clopidogrel 75 mg (p for trend <0.0001), demonstrating the superiority of both doses of prasugrel over 75 and 150 mg clopidogrel. No difference was observed between clopidogrel groups at day 25 (p=0.35), leading to a rebound in HPR and returning to the level of baseline platelet reactivity with both 75 and 150 mg clopidogrel (p=0.66 vs. day 0). conclusion: Prasugrel provides significantly more rapid and more potent platelet reactivity inhibition compared to repeated loading doses of clopidogrel. The observed differences persisted with maintenance dosing, leading to rebound in HPR with both standard and high-dose clopidogrel.

Justification of 150 mg clopidogrel in patients with high on-clopidogrel platelet reactivity: 150 MG CLOPIDOGREL IN HPR

Eur J Clin Invest 2012; 42 (4): 384–392