Laura A. Demopoulos

Comparison of early invasive and conservative strategies in patients with unstable coronary syndromes treated with the glycoprotein IIb/IIIa inhibitor tirofiban.

BACKGROUND There is continued debate as to whether a routine, early invasive strategy is superior to a conservative strategy for the management of unstable angina and myocardial infarction without ST-segment elevation. METHODS We enrolled 2220 patients with unstable angina and myocardial infarction without ST-segment elevation who had electrocardiographic evidence of changes in the ST segment or T wave, elevated levels of cardiac markers, a history of coronary artery disease, or all three findings. All patients were treated with aspirin, heparin, and the glycoprotein IIb/IIIa inhibitor tirofiban. They were randomly assigned to an early invasive strategy, which included routine catheterization within 4 to 48 hours and revascularization as appropriate, or to a more conservative (selectively invasive) strategy, in which catheterization was performed only if the patient had objective evidence of recurrent ischemia or an abnormal stress test. The primary end point was a composite of death, nonfatal myocardial infarction, and rehospitalization for an acute coronary syndrome at six months. RESULTS At six months, the rate of the primary end point was 15.9 percent with use of the early invasive strategy and 19.4 percent with use of the conservative strategy (odds ratio, 0.78; 95 percent confidence interval, 0.62 to 0.97; P=0.025). The rate of death or nonfatal myocardial infarction at six months was similarly reduced (7.3 percent vs. 9.5 percent; odds ratio, 0.74; 95 percent confidence interval, 0.54 to 1.00; P<0.05). CONCLUSIONS In patients with unstable angina and myocardial infarction without ST-segment elevation who were treated with the glycoprotein IIb/IIIa inhibitor tirofiban, the use of an early invasive strategy significantly reduced the incidence of major cardiac events. These data support a policy involving broader use of the early inhibition of glycoprotein IIb/IIIa in combination with an early invasive strategy in such patients.

Comparison of two platelet glycoprotein IIb/IIIa inhibitors, tirofiban and abciximab, for the prevention of ischemic events with percutaneous coronary revascularization.

BACKGROUND In the setting of percutaneous coronary revascularization, agents in the class known as platelet glycoprotein IIb/IIIa inhibitors have significantly reduced the incidence of death or nonfatal myocardial infarction at 30 days. We assessed whether there are differences in safety or efficacy between two such inhibitors, tirofiban and abciximab. METHODS Using a double-blind, double-dummy design at 149 hospitals in 18 countries, we randomly assigned patients to receive either tirofiban or abciximab before undergoing percutaneous coronary revascularization with the intent to perform stenting. The primary end point was a composite of death, nonfatal myocardial infarction, or urgent target-vessel revascularization at 30 days. The trial was designed and statistically powered to demonstrate the noninferiority of tirofiban as compared with abciximab. RESULTS The primary end point occurred more frequently among the 2398 patients in the tirofiban group than among the 2411 patients in the abciximab group (7.6 percent vs. 6.0 percent; hazard ratio, 1.26; one-sided 95 percent confidence interval of 1.51, demonstrating lack of equivalence, and two-sided 95 percent confidence interval of 1.01 to 1.57, demonstrating the superiority of abciximab over tirofiban; P=0.038). The magnitude and the direction of the effect were similar for each component of the composite end point (hazard ratio for death, 1.21; hazard ratio for myocardial infarction, 1.27; and hazard ratio for urgent target-vessel revascularization, 1.26), and the difference in the incidence of myocardial infarction between the tirofiban group and the abciximab group was significant (6.9 percent and 5.4 percent, respectively; P=0.04). The relative benefit of abciximab was consistent regardless of age, sex, the presence or absence of diabetes, or the presence or absence of pretreatment with clopidogrel. There were no significant differences in the rates of major bleeding complications or transfusions, but tirofiban was associated with a lower rate of minor bleeding episodes and thrombocytopenia. CONCLUSIONS Although the trial was intended to assess the noninferiority of tirofiban as compared with abciximab, the findings demonstrated that tirofiban offered less protection from major ischemic events than did abciximab.

Evaluation of B-type natriuretic peptide for risk assessment in unstable angina/non-ST-elevation myocardial infarction: B-type natriuretic peptide and prognosis in TACTICS-TIMI 18.

OBJECTIVES This study was designed to evaluate B-type natriuretic peptide (BNP) for risk assessment and clinical decision making over a range of cut points, alone and with cardiac troponin I (cTnI), in patients with non-ST-elevation acute coronary syndromes (ACS). BACKGROUND B-type natriuretic peptide holds promise for risk stratification. Additional evidence regarding optimal decision limits, use in combination with troponin, and use in targeting therapy is needed before acceptance into clinical use for ACS. METHODS We evaluated BNP at baseline in 1,676 patients with non-ST-elevation ACS randomized to early invasive versus conservative management. RESULTS Patients with elevated BNP (>80 pg/ml; n = 320) were at higher risk of death at seven days (2.5% vs. 0.7%, p = 0.006) and six months (8.4% vs. 1.8%, p < 0.0001). The association between BNP and mortality at six months (adjusted odds ratio [OR] 3.3; 95% confidence interval [CI] 1.7 to 6.3) was independent of important clinical predictors, including cTnI and congestive heart failure (CHF). Patients with elevated BNP had a fivefold higher risk of developing new CHF by 30 days (5.9% vs. 1.0%, p < 0.0001). B-type natriuretic peptide added prognostic information to cTnI, discriminating patients at higher mortality risk among those with negative (OR 6.9; 95% CI 1.9 to 25.8) and positive (OR 4.1; 95% CI 1.9 to 9.0) baseline cTnI results. No difference was observed in the effect of invasive versus conservative management when stratified by baseline levels of BNP (p(interaction) > or = 0.6). CONCLUSIONS Elevated BNP (>80 pg/ml) at presentation identifies patients with non-ST-elevation ACS who are at higher risk of death and CHF and adds incremental information to cTnI. Additional work is needed to identify therapies that may reduce the risk associated with increased BNP.

Differential Expression of Cardiac Biomarkers by Gender in Patients With Unstable Angina/Non–ST-Elevation Myocardial Infarction: A TACTICS-TIMI 18 (Treat Angina with Aggrastat and determine Cost of Therapy with an Invasive or Conservative Strategy–Thrombolysis In Myocardial Infarction 18) Substudy

Background—Diagnosis of coronary artery disease in women is more difficult because of lower specificity of symptoms and diagnostic accuracy of noninvasive testing. We sought to examine the relationship between gender and cardiac biomarkers in patients with unstable angina (UA)/non–ST-segment elevation myocardial infarction (NSTEMI). Methods and Results—In the TACTICS-TIMI 18, OPUS-TIMI 16, and TIMI 11 studies, baseline samples were analyzed in the Thrombolysis In Myocardial Infarction (TIMI) biomarker core laboratory. We examined the relationship between gender and elevated biomarkers. Of 1865 patients from TACTICS-TIMI 18, 34% were women. Fewer women had elevated creatine kinase-MB or troponins, whereas more had elevated high-sensitivity C-reactive protein or brain natriuretic peptide. Presence of ST-segment deviation and TIMI risk scores were not significantly different. This pattern was confirmed in TIMI 11 and OPUS-TIMI 16. The prognostic value of the markers in TACTICS-TIMI 18 was similar in women and men. When a multimarker approach was examined, a greater proportion of high-risk women were identified. Marker-positive patients of both genders had improved outcome with an invasive strategy; however, marker-negative women appeared to have improved outcomes with a conservative strategy. Conclusions—In patients with UA/NSTEMI, there was a different pattern of presenting biomarkers. Men were more likely to have elevated creatine kinase-MB and troponins, whereas women were more likely to have elevated C-reactive protein and brain natriuretic peptide. This suggests that a multimarker approach may aid the initial risk assessment of UA/NSTEMI, especially in women. Further research is necessary to elucidate whether gender-related pathophysiological differences exist in presentation with acute coronary syndromes.

Elevations in Troponin T and I Are Associated With Abnormal Tissue Level Perfusion A TACTICS-TIMI 18 Substudy

Background—Cardiac troponin T (cTnT) and I elevations are associated with a higher risk of adverse events, a higher incidence of multivessel disease, complex lesions, and visible thrombus in the setting of non-ST elevation (NSTE) acute coronary syndromes (ACS). Other pathophysiological mechanisms underlying troponin elevation remain unclear. Methods and Results—We evaluated the relationship between troponin elevation and tissue level perfusion using the TIMI myocardial perfusion grade (TMPG) in 310 patients with NSTE-ACS in the Treat Angina with Aggrastat and Determine Cost of Therapy with an Invasive or Conservative Strategy-Thrombolysis in Myocardial Infarction (TACTICS-TIMI) 18 trial. TMPG 0/1 (“closed” microvasculature) was observed more frequently in cTnT-positive patients both before (58.1% versus 42.1%;P =0.007) and after percutaneous coronary intervention (55.4% versus 35.6%;P =0.004). cTnT levels were higher among patients with TMPG 0/1 versus patients with TMPG 2/3 (0.50 versus 0.31 ng/mL;P =0.006). cTnT-positive patients were more likely to have thrombus (42.5% versus 29.3%), tighter stenoses (72.0% versus 64.8%), and higher rates of TIMI flow grade 0/1 (15.6% versus 7.0%; all P <0.05). TMPG 0/1 remained independently associated with cTnT elevation (odds ratio, 1.81;P =0.02), even after adjusting for epicardial TIMI flow grade, presence of thrombus, and prior myocardial infarction. TMPG 0/1 flow both before and after intervention was associated with increased risk of death or myocardial infarction at 6 months. Conclusions—Similar to what has been observed in the setting of ST-elevation myocardial infarction, abnormal tissue level perfusion is also associated with adverse outcomes in the NSTE-ACS setting. Independent of the presence of thrombus and abnormal flow in the epicardial artery, impaired tissue level perfusion is associated with a 1.8-fold increased risk of cTnT elevation.

Invasive versus conservative strategies in unstable angina and non\NQ-wave myocardial infarction following treatment with tirofiban: rationale and study design of the international TACTICS-TIMI 18 trial ☆

Abstract In the management of unstable angina and non–Q-wave acute myocardial infarction (AMI), there is considerable debate regarding the use of invasive strategy versus conservative strategy. The Thrombolysis In Myocardial Infarction (TIMI) III B trial found similar clinical outcomes for the 2 strategies, but the Veterans Administration Non–Q-Wave Infarction Strategies in-Hospital trial found a higher mortality with the invasive strategy. Both these trials were conducted before platelet glycoprotein IIb/IIIa inhibition and coronary stenting, both of which improve clinical outcome. Thus, there is a need to reexamine the question of which management strategy is optimal in the current era of platelet glycoprotein IIb/IIIa inhibition and new coronary interventions. The Treat Angina with Aggrastat and determine Cost of Therapy with an Invasive or Conservative Strategy (TACTICS-TIMI 18) trial is an international, multicenter, randomized trial that is evaluating the clinical efficacy of early invasive and early conservative treatment strategies in patients with unstable angina or non–Q-wave AMI treated with tirofiban, heparin, and aspirin. Patients are randomized to an invasive strategy, involving cardiac catheterization within 4 to 48 hours and revascularization with angioplasty or bypass surgery if feasible, versus a conservative strategy, where patients are referred for catheterization only for recurrent pain at rest or provokable ischemia. The primary end point is death, MI, or rehospitalization for acute coronary syndromes through a 6-month follow-up. The trial is also testing the “troponin hypothesis,” that baseline troponins T and I will be useful in selecting an optimal management strategy.

Impact of Different Platelet Glycoprotein IIb/IIIa Receptor Inhibitors Among Diabetic Patients Undergoing Percutaneous Coronary Intervention Do Tirofiban and ReoPro Give Similar Efficacy Outcomes Trial (TARGET) 1-Year Follow-Up

Background—The platelet glycoprotein IIb/IIIa receptor inhibitor abciximab, a monoclonal antibody, has been shown to improve early and late outcomes among diabetic patients undergoing percutaneous coronary intervention (PCI). It is unknown whether small-molecule agents confer similar benefits. Methods and Results—In 18 countries, 4809 patients undergoing PCI with stent implantation were randomized to tirofiban or abciximab. At the time of enrollment, patients were stratified according to diabetes status. As compared with non-diabetic patients, patients with diabetes (n=1117) showed similar 30-day ischemic outcomes, an increased incidence of any target vessel revascularization (TVR) at 6 months (10.3% versus 7.8%;P = 0.008), and a trend toward higher 1-year mortality (2.5% versus 1.6%;P =0.056). Among diabetic patients randomized to tirofiban (n=560), the incidence of death, myocardial infarction (MI), or urgent TVR at 30 days was 6.2%, and among those randomized to abciximab (n=557) it was 5.4% (hazard ratio [HR] 1.16;P =0.540). At 6 months, the composite of death, MI, or any TVR occurred in 15.7% and in 16.9% of tirofiban and abciximab patients, respectively (HR 0.93;P =0.610). Any TVR occurred in 9.5% and 11.1%, respectively (HR 0.84;P = 0.366). The 1-year mortality was 2.1% in the tirofiban group and 2.9% in the abciximab group (HR 0.74;P = 0.436). Conclusions—Among diabetic patients undergoing PCI, tirofiban and abciximab were associated with comparable event rates, including similar rates of 6-month TVR and 1-year mortality. These findings suggest that the non-glycoprotein IIb/IIIa properties of abciximab do not translate into a discernible long-term clinical benefit among diabetic patients.

Outcomes at 6 months for the direct comparison of tirofiban and abciximab during percutaneous coronary revascularisation with stent placement: the TARGET follow-up study.

BACKGROUND Two placebo-controlled trials testing intravenous platelet glycoprotein IIb/IIIa antagonists in the setting of percutaneous coronary revascularisation with intracoronary stents have shown a durable reduction in ischaemic events to 6 months. These trials differed regarding their patient population, IIb/IIIa inhibitor, and reported extent of benefit. Whether a small-molecule agent affecting only the IIb/IIIa receptor would provide a similar outcome for ischaemic events and clinical restenosis at 6 months when directly compared with a monoclonal antibody known to affect several integrin receptors is unknown. METHODS In 18 countries at 149 hospitals, 4809 patients undergoing elective or urgent stent implantation were randomly assigned a bolus and infusion of tirofiban or abciximab. Patients were followed for 6 months for the occurrence of death, myocardial infarction, and any target-vessel revascularisation. The results at 30 days have been reported previously. FINDINGS At 6 months the composite endpoint of death, myocardial infarction, and target-vessel revascularisation occurred in 356 (14.8%) patients who received tirofiban and 345 (14.3%) patients who received abciximab (hazard ratio 1.04, 95% CI 0.90-1.21; p=0.591). The rates for the individual endpoints were 191 (8.0%) versus 159 (6.6%) for myocardial infarction (hazard ratio 1.21, 95% CI 0.98-1.50; p=0.074), 26 (1.1%) versus 25 (1.0%) for death (1.04, 0.60-1.80; p=0.893), and 194 (8.1%) versus 208 (8.6%) for target-vessel revascularisation (0.93, 0.77-1.14; p=0.495). INTERPRETATION At 6 months, tirofiban provided a similar level of overall protection to abciximab against the composite of death, myocardial infarction, and any target-vessel revascularisation.

Prospective analysis of creatine kinase muscle-brain fraction and comparison with troponin T to predict cardiac risk and benefit of an invasive strategy in patients with non-ST-elevation acute coronary syndromes.

OBJECTIVE We sought to determine whether elevation of plasma creatine kinase muscle-brain fraction (CK-MB) would be useful to triage patients with acute coronary syndromes (ACS) to early angiography/revascularization. BACKGROUND It is unknown whether the measurement of CK-MB is effective for triage to an aggressive management strategy. METHOD Patients in the Treat Angina With Aggrastat and Determine Cost of Therapy With an Invasive or Conservative Strategy (TACTICS-TIMI) 18 study received aspirin, heparin, and tirofiban for treatment of ACS, were randomized to an invasive or a conservative strategy (angiography/revascularization between 4 and 48 h), and were followed up for a composite end point of death, myocardial infarction, or rehospitalization for ACS. Of 2,220 patients, CK-MB was elevated in 826 (37%). Of the patients with negative CK-MB, troponin T was elevated in 361 (31.2%). Event rates at 30 and 180 days were twice as high in patients with elevated CK-MB than in patients without elevated CK-MB. Both groups had similar benefit from an invasive strategy; there was no evidence of interaction between CK-MB elevation and strategy on the composite end point at 30 or 180 days. When patients were stratified according to both CK-MB and troponin status, there was evidence of a benefit in the invasive strategy among patients who were CK-negative but troponin-positive (odds ratios [95% confidence interval]: 0.13 [0.04 to 0.39] at 30 days and 0.29 [0.16 to 0.52] at 180 days). CONCLUSION Patients with minimal amounts of recent onset myonecrosis but elevated risk as indicated by CK-MB and troponin, respectively, benefit most from invasive management. Determination of troponin levels yielded significant information regarding triage to an invasive strategy, particularly in CK-MB-negative patients.

Efficacy and safety of multivessel percutaneous revascularization and tirofiban therapy in patients with acute coronary syndromes

uated the same effi cacy and safety end points as in the main trial, using similar statistical tests. These in- cluded death from any cause, myocardial infarction (creatine kinase-MB elevation above normal without PCI and 3 times the upper limit normal after PCI), repeat hospitalization for ACS, as well as revascular- ization procedures involving the culprit vessel or ad- ditional vessels. Of the 2,220 patients enrolled in TACTICS TIMI 18, 1,114 were assigned to the invasive strategy. Most (97%) underwent angiography within 48 hours and 41% had PCI. Twenty-nine patients were excluded because PCI was performed only on nonculprit ves- sels. The remaining 427 patients comprised the study population; their baseline characteristics are listed in Table 1. Two-thirds of the patients had MV disease and only 23% of these patients had MV PCI. Prior infarction and surgical revascularization occurred sig- nifi cantly more frequently in the patients with MV disease. Among patients with MV disease and MV PCI, most (89%) had 2 dilated vessels.