Antonio de Miguel

La reestenosis en el stent depende del daño vascular inducido. ¿Son válidos los modelos experimentales actuales de análisis de los stents farmacoactivos?

INTRODUCTION AND OBJECTIVES Drug-eluting stents are useful for preventing restenosis, but the patho-physiological processes involved in the proliferative response after implantation are still not known in detail. The aim of this study is to compare the coronary vascular histomorphometry after implanting drug-eluting stents and bare metal stents in a swine model. METHODS Sixty stents were randomly implanted in 20 Large White female pigs with a ratio of baremetal/drug-eluting stents of 1:2. After 28 days, euthanasia and histomorphometry were performed. We defined the vessel injury score in accordance to whether the internal elastic lamina was intact or ruptured. RESULTS There were no differences between drug-eluting stents and bare metal stents in the intact internal elastic lamina group regarding neointimal area or % restenosis (1.3 [1.1-2.2]) vs 2.0 [1.3-2.5] mm²; P=.6; and 14.0 [12.1-20.8] vs 22.2 [14.1-23.3] %; P=.5). We assessed statistically significant differences for the ruptured internal elastic lamina group, (neointimal area 1.2 [0.8-2.0] vs 2.9 [2.3-3.7] mm²; P=.001 and % restenosis 16.63 [11.2-23.5] vs 30.4 [26.4-45.7] %; P=.001). CONCLUSIONS In our swine model, we did not find any differences between proliferative response of drug-eluting stents and bare metal stents when the internal elastic lamina is intact; differences are only found when vascular injury is deeper.

P2Y12 platelet reactivity after thrombolytic therapy for ST-segment elevation myocardial infarction

INTRODUCTION Thrombolysis, as reperfusion therapy for ST segment elevation myocardial infarction (STEMI), induces a pro-thrombotic status with enhanced platelet activity; this study aims to evaluate P2Y12 platelet reactivity and response to clopidogrel in the post-thrombolysis scenario. MATERIALS AND METHODS Observational, prospective study, including consecutive patients with elective angiography after thrombolytic therapy for STEMI. Every patient received antiplatelet therapy with loading doses of 250 mg aspirin and 300 mg clopidogrel on admission followed by 100mg aspirin and 75 mg clopidogrel daily. P2Y12-dependent platelet reactivity (expressed in P2Y12-Reaction Units, PRU) was assessed with VerifyNow® device on admission, daily after thrombolysis and pre-angiography. RESULTS 41 patients fulfilled the inclusion criteria. Median time between thrombolysis and angiography was 2,5 days (IQR 1,8-4,1). Post-treatment platelet reactivity (PPR) showed poor correlation with time on clopidogrel treatment (r2=0.04) and reached a maximum value of 274 ± 84 PRU during the first 24h after thrombolysis (Day +1 determination). After this, values showed a progressive reduction until the point of angiography (249 ± 82 PRU), without significant differences between consecutive time-points (p=0,549). Inhibition of platelet aggregation (IPA) assessed as a percentage of P2Y12 receptor blockage was poor, increasing gradually from 0 ± 4% on admission to 11 ± 6% the day of the angiography (p=0,001). 71,4% of patients showed PPR ≥ 208 PRU during angiography. CONCLUSIONS Platelet reactivity, as assessed by post-treatment P2Y12 mediated reactivity, is heightened after thrombolytic therapy during STEMI management. In this scenario, standard doses of clopidogrel did not achieve significant inhibition of ADP-mediated platelet reactivity.

Influence of platelet reactivity and response to clopidogrel on myocardial damage following percutaneous coronary intervention in patients with non-st-segment elevation acute coronary syndrome☆

INTRODUCTION A wide variability in the response to clopidogrel and magnitude of post-treatment platelet reactivity has been described. However, this has been demonstrated by light transmittance aggregometry, a method too laborious for daily practice. Point-of-care devices may overcome this limitation, but little is known on the predictive value of such measurements. Our objective was to determine the relationship between platelet reactivity and the incidence of myocardial damage following percutaneous coronary intervention (PCI) in patients with Non-ST-segment Elevation Acute Coronary Syndrome (NSTEACS). MATERIALS AND METHODS This prospective study included 93 patients with NSTEACS and PCI. All patients received a loading dose of 300 mg of clopidogrel and 250 mg of aspirin. Myocardial damage was defined as any elevation above upper limit of normal or previous levels of troponin T, assessed every 6 h for at least 24 h following PCI. Platelet reactivity not related to clopidogrel (BASE reactivity), related to P2Y12 inhibition (P2Y12 reactivity) and inhibition of platelet aggregation (IPA) were assessed immediately pre-PCI with the VerifyNow device. RESULTS Myocardial damage was detected in 60 patients (64.5%). Higher BASE reactivity was associated with myocardial damage (287.8+/-62.6 vs. 260+/-55.9 units, p=0.043) while a trend was found for P2Y12 reactivity (173.4+/-70.3 vs. 149.2+/-58.4 units, p=0.109). No relationship was detected for IPA. Multivariate logistic regression analysis confirmed that BASE reactivity (p=0.04) and P2Y12 reactivity (p=0.03) were independent predictors of myocardial damage. CONCLUSIONS Platelet reactivity before PCI appears to be better predictor of myocardial damage than does response to clopidogrel.

Platelet Reactivity and Stent Thrombosis: Still Some Issues to Solve

We read with great interest the recent article by Sibbing et al. ([1][1]). They concluded that low response to clopidogrel assessed with multiple electrode platelet aggregometry (MEA) is significantly associated with an increased risk of stent thrombosis. Considering the potential clinical

Mitral valve prosthesis implanted in atrial wall over huge calcified annulus

We describe an alternative technique for mitral valve replacement in patients with severe mitral annular calcification, in whom conventional techniques are not feasible. A new annulus that allows supra-annular prosthetic implantation is created.

TCT-371 Anatomical complications and difficulties of the radial and ulnar access for percutaneous coronary interventions: analysis in more than 10,000 patients

Nowadays, more centers worlwide preferred the radial access as first choice to perform left cardiac catheterization. However, the radial approach might challenge operators with several anatomical problems and complications such as accessory radial artery, tortuosity, loop, spasm, dissection,

Trends in Degenerative Aortic Disease: Novel Alternative Therapies for the Treatment of Severe Aortic Stenosis

Aortic stenosis is the most common valvular disease among the occidental population and it is one of the most important causes of morbidity and mortality in developed countries. It has an incidence of 4% among over 80 years old patients (Charlson E et al.,2006). Its evolution is generally slowly progressive from asymptomatic/mild aortic stenosis to the symptomatic/severe form when survival is dramatically reduced as well as quality of live is importantly impaired. (Iung B et al., 2003) All along natural history of this disease, patients will consult several times to specialists in order to adjust medical treatment and perform the indicated diagnostic tests. Occasionally in-hospital admittance will be unavoidable and this will necessarily arise into economic resources consumption, that might be assumed by actually over-the-edge and almost bankrupted socio-sanitary policies, at least in the most of developed countries (Varadarajan P, 2006; Pai RG, 2006). Over more tan 40 years, standard treatment for severe symptomatic aortic stenosis has been focused in surgical replacement of the affected valve for a mechanical prosthesis. To achieve this replacement, patient must mandatorily undergo several risky procedures as general anesthesia, median sternotomy, and aortic arch clamping and cardioplegic solution infusion in order to maintain cardiac arrest in diastole during the intervention, with the indispensable cardiopulmonary bypass pumping. (Kvidal P et al,. 2000) Hence, standard surgical therapy has inherent morbi-mortality risks itself that must be carefully evaluated, so this therapy may be not suitable for a subpopulation of candidates because of an excessive high-risk profile. These patients must then admit the natural history of this disease with a terribly poor mid-term prognosis and elevated economic expenses for the system. (Alexander KP et al., 2000) Socio-sanitary policies need to organize the diagnostic and therapeutic procedures in this cohort of patients in order to obtain the necessary balance that allow an adequate treatment with risk minimization achieving the best possible results with the lowest expenses, optimizing the efficiency in the management of these complex pathology. In this moment, several therapeutic alternatives are being studied with the aim of the risk reduction in the management of patients with severe aortic stenosis and surgical high-risk profile. These therapies do not pretend to become a substitution of the standard surgical

TIMI myocardial perfusion frame count: Turning blush into numbers†

We read with great interest the article entitled ‘‘TIMI myocardial perfusion frame count: A new method to assess myocardial perfusion and its predictive value for short-term prognosis’’ by Ding et al. [1]. As a research team especially interested in the topic [2,3] addressing some methodological issues would be appreciated. The authors decided to differentiate three groups of TIMI Myocardial Perfusion Frame Counts (TMPFC) to build up predictive models of short-term prognosis. The selection of the lower cut-off point (90 frames, upper 95% CI for normal arteries) seems reasonable. However, why selecting 130 frames, corresponding to the 75th percentile of the TMPFC values, if only three groups will be obtained? Tertiles or quartiles? And if so, why not distributing the values according to the boundaries obtained for each tertile/quartile? As a quantitative parameter, it would be helpful to find the cut-off value with a higher predictive value: area under the curve (AUC) in a receiver operating curve (ROC) analysis. Both myocardial blush grade (MBG) [4] and TIMI myocardial perfusion grade (TMPG) [5] have been independently correlated with long-term prognosis after acute myocardial infarction. In fact, one of the strongest points of these scoring systems is the ability to categorize patients into different subgroups (and outcomes) when the epicardial coronary flow is fully restored (i.e., TIMI 3 flow). It would be very interesting to detail the relationship between TMPFC and the rest of the analyzed parameters in the subgroup of patients with final TIMI 3 flow, and, even more, to detail the short-term prognostic significance of TMPFC in this subset of patients. The authors supply some data on the prognostic significance of TMPFC, MBG, and TMPG. Three different logistic regression analyses show the independent relationship of these variables with MACE. Could a model including all these variables elucidate the individual predictive value of each one? Otherwise, the authors could report the c-statistic, 22 likelihood ratio, or any goodness-of-fit test to compare the relative predictive power of each. Finally, the authors make a mistake when they state ‘‘to our knowledge, there has been no method for quantitative evaluation of TMPG until now.’’ Our group published such a method 5 years ago: the Coronary Clearance Frame Count (CCFC) [2]. The subjective nature of MBG and TMPG analyses cited by Ding et al. and the intraobserver and interobserver variability [6] led us to develop this index. In 147 patients, we demonstrated a good correlation between CCFC and TMPG; a cut-off value of 54 frames (filming speed of 30 frames per second) showed an AUC value of 0.8, sensitivity of 75%, and specificity of 70% to predict a TMPG 2 or 3.

Giant left main coronary artery to right atrium fistula

Aneurysmal arterial origin of coronary fistulae is an extremely rare combination. We report a case of a giant left main coronary artery to right atrium fistula in a 48-year-old male. We describe the clinical course and management options.