Cafer Zorkun

Angiographic and Clinical Outcomes Among Patients With Acute Coronary Syndromes Presenting With Isolated Anterior ST-Segment Depression: A TRITON–TIMI 38 (Trial to Assess Improvement in Therapeutic Outcomes by Optimizing Platelet Inhibition With Prasugrel–Thrombolysis In Myocardial Infarction 38) Substudy

OBJECTIVES This study sought to determine angiographic and clinical outcomes among patients with acute coronary syndrome (ACS) presenting with isolated anterior ST-segment depression on 12-lead electrocardiogram (ECG). BACKGROUND In patients with ACS, anterior ST-segment depression on 12-lead ECG may represent plaque rupture with: 1) acute thrombotic occlusion with elevation of cardiac biomarkers (+Tn); 2) a patent artery with +Tn; or 3) a patent artery with -Tn. METHODS The TRITON-TIMI 38 (Trial to Assess Improvement in Therapeutic Outcomes by Optimizing Platelet Inhibition with Prasugrel-Thrombolysis In Myocardial Infarction 38) enrolled 13,608 ACS patients. Those with isolated anterior (leads V(1) to V(4)) ST-segment depression were analyzed. Angiograms and ECGs were interpreted by local investigators. RESULTS There were 1,198 (8.8%) patients with isolated anterior ST-segment depression. Of those, 314 (26.2%) had an occluded culprit artery (TIMI flow grade 0/1) and +Tn, 641 (53.5%) had a patent culprit artery (TIMI flow grade 2/3) and +Tn, and 243 (20.3%) had TIMI flow grade 2/3 and -Tn. Among patients with an occluded artery, the culprit artery was most often the left circumflex artery (48.4%). The 30-day incidence of the composite of death and MI was significantly higher among patients with an occluded artery (8.6%) than among those with a patent culprit artery and either +Tn (6.3%) or -Tn (2.9%) (3-way p = 0.006). Among patients with an occluded artery, the median time from ECG to percutaneous coronary intervention was 29.4 h (interquartile range 26.1 to 44.1 h). CONCLUSIONS Among ACS patients presenting with isolated anterior ST-segment depression, over one-quarter had an occluded culprit artery and elevated cardiac biomarkers. These patients had significantly worse clinical outcomes, and few underwent urgent angiography.

Use of the TIMI frame count in the assessment of coronary artery blood flow and microvascular function over the past 15 years

Since its introduction, the TIMI frame count method has contributed to the understanding of the pathophysiology of coronary artery disease. In this article, the evolution of the TFC method and its applicability in the assessment of various therapeutic modalities are described.

Effect of prasugrel versus clopidogrel on outcomes among patients with acute coronary syndrome undergoing percutaneous coronary intervention without stent implantation: A TRial to assess Improvement in Therapeutic Outcomes by optimizing platelet inhibitioN with prasugrel (TRITON)–Thrombolysis in Myocardial Infarction (TIMI) 38 Substudy

BACKGROUND Prasugrel led to a significant reduction in ischemic cardiovascular events among patients with acute coronary syndrome (ACS) undergoing percutaneous coronary intervention (PCI) with stent implantation compared to clopidogrel. Whether this benefit extends to patients undergoing PCI without stent implantation is unknown. METHODS In TRial to assess Improvement in Therapeutic Outcomes by optimizing platelet inhibitioN with prasugrel (TRITON)-Thrombolysis in Myocardial Infarction (TIMI) 38, patients (n = 13 608) undergoing PCI for ACS were randomized to aspirin plus clopidogrel or prasugrel. This postrandomization analysis of a prespecified subgroup was restricted to patients who underwent PCI without stent implantation (n = 569). RESULTS Patients who underwent PCI without stent implantation were older and had a higher incidence of hypertension, diabetes, prior myocardial infarction (MI), prior coronary artery bypass (CABG) surgery, and renal dysfunction than patients who underwent stent implantation. In the group that did not undergo stent implantation, baseline characteristics were similar between patients receiving clopidogrel and prasugrel. The composite of cardiovascular death, nonfatal MI, and nonfatal stroke occurred in 14.2% of patients receiving prasugrel and 17.1% of patients receiving clopidogrel (HR 0.82, P = .27). There were significant reductions favoring prasugrel in the rates of urgent target vessel revascularization (TVR; HR 0.46, P = .040) and any TVR (HR 0.40, P = .009) and a trend toward a reduction in the incidence of nonfatal MI (HR 0.65, P = .11). CABG-related TIMI major bleeding was more frequent among patients receiving prasugrel. There were no significant interactions between treatment and PCI type. CONCLUSION Among ACS patients who underwent PCI without stent implantation, prasugrel therapy tended to reduce clinical ischemic events and to increase bleeding events to a similar magnitude as among patients who received stents.

Angiographic Outcomes in the PLATO Trial (Platelet Inhibition and Patient Outcomes)

OBJECTIVES The PLATO (Platelet Inhibition and Patient Outcomes) angiographic substudy sought to compare the efficacy of ticagrelor versus clopidogrel with respect to angiographic outcomes before and after PCI in the setting of acute coronary syndrome. BACKGROUND Greater platelet inhibition has been associated with improved angiographic outcomes before and after percutaneous coronary intervention (PCI). Therefore, it was hypothesized that treatment with ticagrelor, which achieves more rapid, higher, and more consistent platelet inhibition, would be associated with improved angiographic outcomes when compared with those of clopidogrel treatment. METHODS The angiographic cohort consists of 2,616 patients drawn from the 18,624-patient PLATO trial. Clopidogrel naïve or pre-treated patients were randomized to 180 mg of ticagrelor or 300 mg of clopidogrel (75 mg for clopidogrel pre-treated patients). PCI patients were administered, as per treatment group: 1) an additional 90 mg of ticagrelor if >24 h following the initial loading dose; or 2) an optional further 300 mg of clopidogrel or placebo (total 600 mg) prior to PCI. The substudy primary endpoint was the incidence of post-PCI TIMI (Thrombolysis In Myocardial Infarction) myocardial perfusion grade 3 (TMPG 3) among patients who received a study drug prior to PCI. RESULTS In total, 21.3% of patients were pretreated with clopidogrel prior to randomization. There was a short time interval between randomization and PCI (median: 0.68 [interquartile range (IQR): 0.30 to 2.21] h) among all patients. Post-PCI TMPG 3 was similar between the ticagrelor and clopidogrel groups (47.1% vs. 46.9%; p = 0.96). Likewise, the following pre-PCI outcomes were similar in the ticagrelor and clopidogrel groups, respectively: TMPG 3 (30.5% vs. 31.2%), TIMI flow grade 3 (37.1% vs. 39.3%), corrected TIMI frame count (median: 100 vs. 71 frames), TIMI thrombus grade 0 (24.1% vs. 27.6%), minimum lumen diameter (median: 0.3 [IQR: 0.0 to 0.6] vs. 0.3 [IQR: 0.0 to 0.6] mm) and percentage of diameter stenosis (median: 89 [IQR: 78 to 100] vs. 89 [IQR: 77 to 100]). CONCLUSIONS Neither coronary flow nor myocardial perfusion, evaluated on coronary angiograms performed before or following PCI procedures within a few hours after the start of oral antiplatelet treatment in the setting of acute coronary syndromes, demonstrated a difference with ticagrelor versus clopidogrel. (A Comparison of Ticagrelor [AZD6140] and Clopidogrel in Patients With Acute Coronary Syndrome [PLATO]; NCT00391872).

Intracoronary pharmacotherapy in the management of coronary microvascular dysfunction

Although percutaneous coronary intervention restores optimal epicardial blood flow in most cases, abnormal myocardial perfusion may still persist. This might be as a result of macro and microembolization, neutrophil plugging, vasoconstriction, myocyte contracture, local intracellular and interstitial edema, intramural haemorrhage, and endothelial blistering. Local delivery of intracoronary pharmacotherapy via the coronary arteries may increase local drug concentration several fold, and may improve drug efficacy. Several pharmacological agents such as adenosine, calcium channel blockers, α blockers, β2 receptor activators, vasodilators, antithrombotics, and antiplatelet agents have been used to treat coronary microvascular dysfunction. This article reviews the results of trials of intracoronary pharmacotherapy to date.

Intracoronary Administration of Abciximab in ST-Elevation Myocardial Infarction

Primary percutaneous coronary intervention (PCI) is now the preferred method of treating patients with ST-elevation myocardial infarction (STEMI). Despite restoration of epicardial flow, microvascular obstruction may persist after primary PCI as a result of both atheromatous and thrombotic embolization, neutrophil plugging, edema, and vasospasm.1–3 Therefore, studies such as the one by Thiele et al4 in this issue of Circulation that focus on the prevention and treatment of microvascular dysfunction are informative with respect to the means to improve the primary PCI strategy. Article p 49 There have been efforts to identify mechanical and pharmacological strategies to improve myocardial perfusion after primary PCI. Compared with the systemic administration of intravenous pharmacotherapies, highly localized administration of intracoronary pharmacotherapy may be associated with a several-hundred-fold increase in the local concentration of an agent in the epicardial artery and microcirculation. A number of pharmacotherapies, including adenosine,5,6 calcium channel blockers,7 α-blockers,8 β2-receptor activators,9 other vasodilators, antithrombotics,10,11 and antiplatelet agents,12–14 have been used to treat microvascular dysfunction. There are tens of thousands of glycoprotein IIb/IIIa (GPIIb/IIIa) receptors on the platelet surface.15 Platelet receptor occupancy studies have demonstrated that if there are fewer GPIIb/IIIa receptors free and available for cross-linking with fibrinogen, then myocardial perfusion is improved.16 To estimate the number of GPIIb/IIIa receptors available for cross-linking, the absolute platelet count has been multiplied by the percent of receptors available to cross link to calculate an index of the absolute number of GPIIb/IIIa receptors available. The absolute number of GPIIb/IIIa receptors available for cross-linking is reduced among patients with successful restoration of myocardial perfusion and ST-segment resolution in an STEMI population.16 Thus, the hypothesized mechanistic basis for intracoronary administration of GPIIb/IIIa inhibitors is that high …

Association Between Angiographic Complications and Clinical Outcomes Among Patients With Acute Coronary Syndrome Undergoing Percutaneous Coronary Intervention: An EARLY ACS (Early Glycoprotein IIb/IIIa Inhibition in Non–ST-Segment Elevation Acute Coronary Syndrome) Angiographic Substudy

OBJECTIVES The goal of this analysis was to determine the association between intraprocedural complications and clinical outcomes among patients with high-risk non-ST-segment elevation acute coronary syndrome (NSTEACS) undergoing percutaneous coronary intervention (PCI). BACKGROUND Among patients undergoing PCI for NSTEACS, the relationship between intraprocedural complications and clinical outcomes, independent of epicardial and myocardial perfusion, has not been well characterized. METHODS The EARLY ACS (Early Glycoprotein IIb/IIIa Inhibition in Non-ST-Segment Elevation Acute Coronary Syndrome) trial enrolled 9,406 patients with high-risk NSTEACS undergoing an early invasive strategy. Of these, 1,452 underwent angiographic assessment in an independent core laboratory and did not have a myocardial infarction (MI) between enrollment and angiography. We assessed the relationship between abrupt closure, loss of side branch(es), distal embolization, and no-reflow phenomenon and 30-day clinical outcomes in these patients. RESULTS Of the patients, 166 (11.4%) experienced an intraprocedural complication. Baseline clinical characteristics were similar between patients who did and did not have complications. The 30-day composite of death or MI was significantly higher among patients with an intraprocedural complication (28.3% vs. 7.8%, odds ratio [OR]: 4.68, 95% confidence interval [CI]: 3.2 to 7.0, p < 0.001). Individually, both mortality (3.0% vs. 0.9%, OR: 3.60, 95% CI: 1.2 to 10.5, p = 0.019) and MI (27.1% vs. 7.4%, OR: 4.66, 95% CI: 3.1 to 7.0, p < 0.001) were significantly increased. After adjusting for differences in post-PCI epicardial and myocardial perfusion, the association with 30-day death or MI remained significant. CONCLUSIONS Among high-risk NSTEACS patients undergoing an invasive strategy, the incidence of intraprocedural complications is high, and the occurrence of these complications is associated with worse clinical outcomes independent of epicardial and myocardial perfusion. (Early Glycoprotein IIb/IIIa Inhibition in Patients With Non-ST-segment Elevation Acute Coronary Syndrome [EARLY ACS]; NCT00089895).

Angiographic Outcomes With Early Eptifibatide Therapy in Non–ST-Segment Elevation Acute Coronary Syndrome (from the EARLY ACS Trial)

Early administration of glycoprotein IIbIIIa inhibitors results in improved angiographic parameters, including thrombolysis in myocardial infarction (TIMI) flow grade, corrected TIMI frame count, and TIMI myocardial perfusion grade (TMPG) among patients with ST-segment elevation myocardial infarction. Whether the same is true in the setting of non-ST-segment elevation acute coronary syndrome is unknown. The goal of the early glycoprotein IIbIIIa inhibition in non-ST-segment elevation acute coronary syndrome (EARLY ACS) angiographic substudy was to compare angiographic outcomes among patients with non-ST-segment elevation acute coronary syndrome who were administered early routine versus delayed provisional eptifibatide. Of 9,406 patients in the EARLY ACS trial, 2,066 patients were included in the angiographic substudy (early routine eptifibatide [n=1,042] or early placebo [n=1,024] with delayed provisional eptifibatide after angiography and before percutaneous coronary intervention [PCI]). The angiographic substudy primary end point was the incidence of TMPG 3 before and after PCI. TMPG 3 before (43.7% vs 44.9%, p=0.58) and after PCI (52.4% vs 50.1%, p=0.73) was similar for early routine versus delayed provisional eptifibatide, respectively. Angiographic procedural complications consisting of a composite of loss of side branch, abrupt vessel closure, distal embolization, and no reflow occurred less frequently in early routine group versus delayed provisional group (9.3% vs 13.6%, respectively, p=0.01). In the EARLY ACS angiographic substudy, the use of early routine eptifibatide resulted in fewer angiographic procedural complications. These data provide support for the use of eptifibatide in the catheterization laboratory during high-risk cases merely to prevent angiographic procedural complications.

Dose escalation trial of the efficacy, safety, and pharmacokinetics of a novel fibrinolytic agent, BB-10153, in patients with ST elevation MI: Results of the TIMI 31 trial

Background: Currently available fibrinolytic agents are limited by their ability to restore normal blood flow in only half of patients, the risk of reocclusion, and the risk of intracranial hemorrhage. The genetically engineered agent BB-10153 is activated by thrombin, not plasminogen activator enzymes, which limits its activity to the site of thrombus which may in turn reduce the risk of systemic bleeding. BB-10153 also has a relatively long half-life of 3–4 hours, which may also limit the potential for early reocclusion [1, 2].Methods: The study was a phase II, open-label, multi-center, dose escalation, single-dose administration study to determine the efficacy, safety, tolerability, pharmacokinetics and pharmacodynamics of BB-10153 in ST segment elevation MI (STEMI). STEMI patients (n = 50) received a single dose of BB-10153 at one of six dose levels (1.0, 2.0, 3.0, 5.0, 7.5 and 10 mg/kg). The primary endpoint was TIMI flow grade (TFG) 3 at 60 minutes following the intravenous bolus of BB-10153.Results: Mean area under the curve for drug concentration ranged from 48.0 μg⋅h/mL in the 1 mg/kg dose group to 788.6 μg⋅h/mL in the 10 mg/kg dose group. Likewise, mean Cmax generally increased with dose over the entire dose range, from 4.9 μg/mL in the 1 mg/kg dose group to 139.6 μg/mL in the 10 mg/kg dose group. The mean apparent terminal half-life (t1/2) was 4.4 hours (range 2.2 to 7.6 hours). Few patients in the 1–3 mg/kg dosage groups achieved TFG 3 on the one-hour post-dose angiogram (4/20, 20%), and no patients achieved complete ST segment resolution. The 5, 7.5 and 10 mg/kg doses were associated with similar rates of TIMI grade 3 flow of approximately three per seven patients. Pooling TFG 3 data from the 5, 7.5 and 10 mg/kg groups yielded a TIMI grade 3 flow rate of 34% (n = 10/29; range 29–43%). No patients experienced 30-day death, recurrent acute MI, cardiogenic shock, stroke or anaphylaxis during the study. One patient experienced recurrent angina and developed recurrent myocardial ischemia requiring urgent revascularization. Three patients sustained TIMI major bleeding events (one in 1 mg/kg group, two in 7.5 mg/kg group), six patients sustained TIMI minor bleeds (one in the 2, 3, 7.5 and 10 mg/kg groups, two in the 5 mg/kg group), twp patients sustained TIMI minimal bleeds (one in each of the 2 and 10 mg/kg groups) and no patients sustained intracranial hemorrhage (ICH).Conclusion: In a dose escalation study of a single intravenous bolus, the novel fibrinolytic agent, BB-10153 was associated with a rise in the mean area under the curve and Cmax for drug concentration over the dose range 1 to 10 mg/kg. Higher doses were associated with a range of TIMI grade 3 flow of 29–43%, and no patients experienced 30-day death, recurrent acute MI, cardiogenic shock, stroke or anaphylaxis during the study.Condensed abstractIn a dose escalation study of a single intravenous bolus, the novel fibrinolytic agent, BB-10153 was associated with a rise in the mean area under the curve and Cmax for drug concentration over the dose range 1 to 10 mg/kg. Higher doses were associated with a range of TIMI grade 3 flow of 29–43%, and no patients experienced 30-day death, recurrent acute MI, cardiogenic shock, stroke or anaphylaxis during the study.

Newer Pharmaceutical Agents for STEMI Interventions

ST-elevation myocardial infarction (STEMI) causes 12.6% of deaths worldwide. Treatment strategies involve early revascularization by percutaneous coronary intervention and/or fibrinolytics, with adjunctive pharmacologic therapy. While antiplatelet therapy remains the cornerstone of pharmacologic management, newer antithrombotic therapies are showing benefit in the reduction of long-term thrombotic events following acute vessel occlusion. Future directions in adjunctive STEMI management include the use of hematopoietic stem cell therapy or growth factors to induce proliferation and differentiation of cardiac myocytes.