Harmonizing Outcomes With Revascularization And Stents In Acute Myocardial Infarction Trial Research Articles

Characterization of the Average Daily Ischemic and Bleeding Risk After Primary PCI for STEMI

BackgroundThe risk of recurrent ischemic and bleeding events after primary percutaneous coronary intervention (PCI) for ST-segment elevation myocardial infarction (STEMI) may not be uniform over time, which may affect the benefit-to-risk ratio of guideline-recommended antithrombotic therapies in different intervals. ObjectivesThis study sought to characterize the average daily ischemic rates (ADIRs) and average daily bleeding rates (ADBRs) within the first year after primary PCI for STEMI. MethodsAmong 3,602 patients with STEMI who were enrolled in the HORIZONS-AMI (Harmonizing Outcomes with Revascularization and Stents in Acute Myocardial Infarction) trial, all ischemic and bleeding events, including recurrent events, were classified according to the timing of their occurrence as acute (≤24 h after PCI), subacute (1 day to 30 days), and late (30 days to 1 year). Patients were treated with aspirin and clopidogrel for the entire year. ADIRs included cardiac death, reinfarction, and definite stent thrombosis. ADBRs included non–coronary artery bypass graft–related Thrombolysis In Myocardial Infarction major and minor bleeding. ADIRs and ADBRs were calculated as the total number of events divided by the number of patient-days of follow-up in each interval assuming a Poisson distribution. Generalized estimating equations were used to test the absolute least square mean differences (LSMD) between ADIRs and ADBRs. ResultsThe ADIR and ADBR both exponentially decreased from the acute to the late periods (p < 0.0001). Although there were no significant differences in ADIR and ADBR in the acute phase (LSMD: +0.11%; 95% confidence interval [CI]: −0.35% to 0.58%; p = 0.63), the ADBR was greater than the ADIR in the subacute phase (LSMD: −0.39%; 95% CI: −0.58% to −0.20%; p < 0.0001). In the late phase, the ADIR exceeded the ADBR (LSMD: +1.51%; 95% CI: 1.04% to 1.98%; p < 0.0001). ConclusionsAfter primary PCI, the ADIR and ADBR both markedly decreased over time. Although the rates for bleeding exceeded those for ischemia within 30 days, the daily risk of ischemia significantly exceeded the daily risk of bleeding beyond 30 days, supporting the use of intensified platelet inhibition during the first year after STEMI.

Is routine post-procedural anticoagulation warranted after primary percutaneous coronary intervention in ST-segment elevation myocardial infarction? Insights from the HORIZONS-AMI trial.

Post-procedural anticoagulation (AC) for routine prophylaxis may be administered after primary percutaneous coronary intervention (PCI) in ST-segment elevation myocardial infarction (STEMI), but the risks and benefits of this practice are uncertain. We therefore sought to assess the utility of routine post-procedural AC after primary PCI. Patients undergoing primary PCI in the Harmonizing Outcomes with Revascularization and Stents in Acute Myocardial Infarction (HORIZONS-AMI) trial were grouped according to whether they received post-PCI AC for routine prophylaxis. Outcomes were assessed using propensity-adjusted multivariable analysis. Among 2932 patients in whom primary PCI for STEMI was performed, 869 (29.6%) received post-PCI AC for routine prophylaxis (median duration four days) and 2063 (70.4%) received no post-PCI AC. Time from PCI to ambulation was similar in both groups (median 0.9 vs 1.0 days, p=0.40), although hospitalization was prolonged in patients receiving AC for routine prophylaxis (median 6.0 vs 4.0 days, p<0.0001). After propensity-adjustment, patients who received and did not receive AC for routine prophylaxis after PCI experienced similar rates of 30-day adverse ischemic and major bleeding events. Deep venous thrombosis or pulmonary emboli developed rarely (0.3%) within 30 days, and were not significantly reduced by use of post-PCI AC for routine prophylaxis. In this large-scale prospective study, use of post-procedural AC for routine prophylaxis was relatively common, and was not associated with improved clinical outcomes, although the duration of hospitalization was prolonged. These data suggest that post-PCI AC for routine prophylaxis may not provide benefit after successful primary PCI in patients in whom early ambulation is likely.

Enhancing the Benefit of Bivalirudin in Percutaneous Coronary Intervention: Is High Risk of Bleeding the Key?

Bivalirudin is a potent direct thrombin inhibitor that can reduce thrombus burden during acute coronary syndromes (ACS) and percutaneous coronary intervention (PCI) by blocking formation of fibrin and by suppressing platelet aggregation [1]. When compared with heparin, bivalirudin has several theoretical mechanistic advantages that include activity against clot-bound thrombin, inhibition of thrombin-induced platelet activation, short plasma half-life, linear pharmacokinetics less affected by plasma proteins and renal insufficiency, and an unaffected platelet activation during PCI [1]. These properties of bivalirudin provide a more predictable inhibition of coagulant activity than does heparin, with less degree of inter-patient variability in anticoagulation response. Moreover, its binding to thrombin is non-competitive and reversible, and hemostatic capacity is more readily restored; hence bleeding, as well as ischemic complications, may be reduced [2]. In the first randomized trial (HAS [Hirulog Angioplasty Study]) comparing bivalirudin with heparin in over 4000 patients undergoing PCI for unstable or post-infarction angina, bivalirudin was at least as effective as high-dose heparin in preventing ischemic complications, and it carried a lower risk of bleeding [3]. Nevertheless, development of bivalirudin was suspended because of the unfavorable cost comparison with heparin. Only recently did the development of a less expensive manufacturing process encourage interest from researchers to further support the efficacy and safety of this anticoagulant therapy. Re-analysis of the original HAS using contemporary endpoints and intention-to-treat analysis showed a 22 % reduction in major adverse cardiac events (including death, ACS, and revascularization) and a 62 % reduction in bleeding with bivalirudin at 7 days [4]. In the REPLACE-2 (Randomized Evaluation in PCI Linking Angiomax to Reduced Clinical Events) trial [5], bivalirudin with provisional glycoprotein IIb/IIIa blockade (which was administered in about 7 % of patients) was proven to be statistically non-inferior to heparin plus planned glycoprotein IIb/IIIa inhibitors during PCI with regard to suppressing ischemic events after PCI, but was superior in preventing hemorrhagic complications. More recently, bivalirudin provided similar protection from ischemic events as glycoprotein IIb/IIIa inhibitors, but with lower bleeding rates in the ACUITY (Acute Catheterisation and Urgent Intervention Triage strategy) trial [6]. Although the evidentiary landscape in support of antithrombotic treatment choices during PCI has been enriched by these trials, recent data from clinical trials and pooled analyses questioned the role of bivalirudin in the setting of planned and primary PCI [7–12]. In the HORIZONS-AMI (Harmonizing Outcomes with Revascularization and Stents in Acute Myocardial Infarction) trial, the use of bivalirudin was associated with a This comment refers to the article available at doi:110.1007/s40256015-0113-8.

Bivalirudin Versus Heparin With or Without Glycoprotein IIb/IIIa Inhibitors in Patients With STEMI Undergoing Primary Percutaneous Coronary Intervention

In the HORIZONS-AMI (Harmonizing Outcomes with RevasculariZatiON and Stents in Acute Myocardial Infarction) trial, 3,602 patients undergoing primary percutaneous coronary intervention (PCI) for ST-segment elevation myocardial infarction (STEMI) treated with bivalirudin had lower bleeding and mortality rates, but higher acute stent thrombosis rates compared with heparin+ a glycoprotein IIb/IIIa inhibitor (GPI). Subsequent changes in primary PCI, including the use of potent P2Y12 inhibitors, frequent radial intervention, and pre-hospital medication administration, were incorporated into the EUROMAX (European Ambulance Acute Coronary Syndrome Angiography) trial, which assigned 2,218 patients to bivalirudin versus heparin ± GPI before primary PCI. The goal of this study was to examine the outcomes of procedural anticoagulation with bivalirudin versus heparin ± GPI for primary PCI, given the evolution in primary PCI. Databases from HORIZONS-AMI and EUROMAX were pooled for patient-level analysis. The Breslow-Day test evaluated heterogeneity between trials. A total of 5,800 patients were randomized to bivalirudin (n= 2,889) or heparin ± GPI (n= 2,911). The radial approach was used in 21.3% of patients, prasugrel/ticagrelor was used in 18.1% of patients, and GPI was used in 84.8% of the control group. Bivalirudin compared with heparin ± GPI resulted in reduced 30-day rates of major bleeding (4.2% vs. 7.8%; relative risk [RR]: 0.53; 95% confidence interval [CI]: 0.43 to 0.66; p< 0.0001), thrombocytopenia (1.4% vs. 2.9%, RR: 0.48; 95% CI: 0.33 to 0.71; p= 0.0002), and cardiac mortality (2.0% vs. 2.9%; RR: 0.70; 95% CI: 0.50 to 0.97; p= 0.03), with nonsignificantly different rates of reinfarction, ischemia-driven revascularization, stroke, and all-cause mortality. Bivalirudin resulted in increased acute (<24 h) stent thrombosis rates (1.2% vs. 0.2%; RR: 6.04; 95% CI: 2.55 to 14.31; p< 0.0001), with nonsignificantly different rates of subacute stent thrombosis. Composite net adverse clinical events were lower with bivalirudin (8.8% vs. 11.9%; RR: 0.74; 95% CI: 0.63 to 0.86; p< 0.0001). There was no significant heterogeneity between the 2 trials for these outcomes, and results were consistent across major subgroups. Despite increased acute stent thrombosis, primary PCI with bivalirudin improved 30-day net clinical outcomes, with significant reductions in major bleeding, thrombocytopenia, and transfusions comparedwith heparin ± GPI, results that were consistent with evolution in PCI technique and pharmacotherapy. (Harmonizing Outcomes with RevasculariZatiON and Stents in Acute Myocardial Infarction [HORIZONS-AMI]; NCT00433966) (European Ambulance Acute Coronary Syndrome Angiography [EUROMAX]; NCT01087723).

Association Between Intraprocedural Thrombotic Events and Adverse Outcomes After Primary Percutaneous Coronary Intervention for ST-Segment Elevation Myocardial Infarction (a Harmonizing Outcomes With RevasculariZatiON and Stents in Acute Myocardial Infarction [HORIZONS-AMI] Substudy)

The present study sought to determine the extent to which adverse angiographic events encountered during percutaneous coronary intervention for ST-segment elevation myocardial infarction (STEMI) are associated with adverse clinical outcomes. Patients with STEMI represent a cohort at particularly high risk of intraprocedural thrombotic events (IPTEs). The overall frequency and implications of IPTEs occurring in patients with STEMI have not been systematically quantified in previous studies. A total of 3,163 patients undergoing primary percutaneous coronary intervention with stent implantation for STEMI in the Harmonizing Outcomes with RevasculariZatiON and Stents in Acute Myocardial Infarction (HORIZONS-AMI) trial underwent detailed frame-by-frame core laboratory angiographic analysis to assess IPTEs. The clinical outcomes at 30 days were compared between the patients with and without IPTEs. IPTEs, defined as the development of new or increasing thrombus, abrupt vessel closure, no reflow, slow reflow, and distal embolization at any point during the procedure, occurred in 386 patients (12.2%). The independent predictors of IPTE were thrombus at baseline, lesion length, and randomization to bivalirudin; the patients with IPTEs were also more likely to receive bailout glycoprotein IIb/IIIa inhibitors and unplanned thrombectomy. Compared with patients without IPTEs, the patients with IPTEs had higher 30-day rates of composite major adverse cardiovascular events (death, myocardial infarction, ischemic target vessel revascularization, and stroke; 7.8% vs 4.2%, p = 0.002), major bleeding not related to coronary artery bypass grafting (11.8% vs 6.5%, p <0.001), and all-cause death (4.2% vs 1.8%, p = 0.002). On multivariate analysis, IPTEs were independently associated with 30-day major adverse cardiovascular events, major bleeding, and death. In conclusion, the development of IPTEs in patients undergoing primary percutaneous coronary intervention for STEMI was associated with subsequent adverse outcomes, including major adverse cardiovascular events, major bleeding, and death. Additional studies of strategies to decrease the occurrence of IPTEs are warranted.

Frequency, Mechanisms, and Implications of Late Peri-Stent Contrast Staining: Analysis (from the HORIZONS-AMI Trial)

Previous studies have suggested that angiographically detected persistent contrast staining (PSS) at follow-up may predict subsequent very late stent thrombosis. The Harmonizing Outcomes With Revascularization and Stents in Acute Myocardial Infarction (HORIZONS-AMI) trial was a dual-arm, factorial, randomized trial in patients with ST-segment elevation myocardial infarctions. All follow-up angiograms (1,330 lesions in 1,115 patients, median time 13.3 months) without major cardiovascular events before follow-up angiography were analyzed at a core laboratory blinded to clinical events for the presence of PSS (defined as contrast staining outside the stent contour extending to ≥20% of the stent diameter). Corresponding follow-up intravascular ultrasound (IVUS) data (275 lesions in 248 patients) were also evaluated to assess the mechanisms of PSS. PSS was present in 23 patients (2.1%) at follow-up and was not more common with paclitaxel-eluting than with bare-metal stents. All 6 PSS patients with follow-up IVUS had stent malapposition (vs 41.2% malapposition in the follow-up IVUS cohort). Comparing poststent and follow-up IVUS, 2 patients had late acquired and 4 had persistent malapposition; all 6 showed positive vessel remodeling from baseline to follow-up (mean vessel area 22.0 ± 8.0 to 32.4 ± 11.7 mm(2), p = 0.07). During 3-year follow-up, stent thrombosis developed in no patient with PSS compared with 8 PSS-negative patients (0% vs 0.8%, p = 0.68). The rates of revascularization and major adverse cardiovascular events were also not increased in PSS patients. In conclusion, in the large-scale HORIZONS-AMI trial, PSS at angiographic follow-up was infrequent and was associated with late stent malapposition and positive remodeling but was independent of stent type. Identification of PSS was not associated with subsequent stent thrombosis.

Comparison of Outcomes of Patients With ST-Segment Elevation Myocardial Infarction With Versus Without Previous Coronary Artery Bypass Grafting (from the Harmonizing Outcomes With Revascularization and Stents in Acute Myocardial Infarction [HORIZONS-AMI] Trial)

The present substudy from the Harmonizing Outcomes with Revascularization and Stents in Acute Myocardial Infarction (HORIZONS-AMI) trial assessed the outcomes and their relation to different antithrombotic regimens in patients with previous coronary artery bypass grafting (CABG) treated with primary percutaneous coronary intervention. Of 3,599 patients with information regarding a history of CABG, 105 (2.9%) had previously undergone CABG. Of these 105 patients, 46 were randomized to heparin plus a glycoprotein IIb/IIIa inhibitor and 59 to bivalirudin. The patients with versus without previous CABG were less frequently triaged to primary percutaneous coronary intervention (83.8% vs 93.2%, p= 0.0002) and had a longer door-to-balloon time (median 1.9 vs 1.6 hours, p= 0.047), lower rates of final Thrombolysis In Myocardial Infarction flow grade 2 to 3 in the intervened vessel (92.6% vs 97.8%, p= 0.007), and less frequent rates of complete or partial ST-segment resolution (66.3% vs 77.6%, p= 0.019). At 3 years, previous CABG was associated with a significantly greater incidence of major adverse cardiovascular events (36.4% vs 21.4%, p <0.001) owing to greater rates of mortality (11.2% vs 6.7%, p= 0.08), reinfarction (11.6% vs 7.1%, p= 0.09), stroke (5.1% vs 1.8%, p= 0.013), and ischemic target vessel revascularization (23.6% vs 12.9%, p= 0.005). The outcomes did not differ significantly as a function of the antithrombotic regimen. On multivariate analysis, previous CABG was an independent predictor of 3-year ischemic stroke (hazard ratio 3.57, 95% confidence interval 1.09 to 11.66). Intervention on the saphenous vein graft versus the nativevessel predicted 3-year major adverse cardiovascular events (hazard ratio 2.69, 95% confidence interval 1.17 to 6.19). In the HORIZONS-AMI trial, previous CABG was associated with a delay to mechanical reperfusion and lower rates of percutaneous coronary intervention and patency of the infarct related vessel along with worse clinical outcomes.

Dynamic Nature of Nonculprit Coronary Artery Lesion Morphology in STEMI: A Serial IVUS Analysis From the HORIZONS-AMI Trial

The authors sought to report the temporal stability of an untreated, nonculprit lesion phenotype in patients presenting with ST-segment elevation myocardial infarction (STEMI). The temporal stability of the untreated, nonculprit lesion phenotype has been studied using intravascular ultrasound-virtual histology (IVUS) in patients with stable ischemic heart disease, but not in STEMI patients. As part of a formal substudy of the HORIZONS-AMI (Harmonizing Outcomes With Revascularization and Stents in Acute Myocardial Infarction) trial, baseline and 13-month follow-up IVUS was performed in 99 untreated nonculprit lesions in 63 STEMI patients. Lesions were classified as pathological intimal thickening (PIT), IVUS-derived thin-cap fibroatheroma (TCFA), thick-cap fibroatheroma (ThCFA), fibrotic plaque, or fibrocalcific plaque. The frequency of TCFA increased from 41% at baseline to 54% at follow-up, whereas ThCFAs decreased from 41% to 34% and PIT decreased from 16% to 8%. Among the 41 lesions classified at baseline as TCFA, at follow-up, 32 (78%) were still classified as TCFA, whereas 9 (22%) were classified as ThCFAs or fibrotic plaques. An additional 21 lesions at follow-up were newly classified as TCFA, developing from either PIT or ThCFA. TCFA at baseline that evolved into non-TCFAs trended toward a more distal location than TCFA that did not change (p = 0.12). In lesions classified as TCFA, the minimum lumen area (MLA) decreased from 8.1 (interquartile range [IQR]: 7.4 to 8.8) mm(2) at baseline to 7.8 (IQR: 7.2 to 8.4) mm(2) at follow-up, p < 0.05; this was associated with an increase in percent necrotic core at the MLA site (14% [IQR: 12 to 16] to 19% [IQR: 17 to 22], p < 0.0001) and over the entire length of the lesion (14% [IQR: 12 to 16] to 18% [IQR: 17 to 20], p < 0.0001). Untreated nonculprit lesions in STEMI patients frequently have TCFA morphology that does not change during 13-month follow-up and is accompanied by a decrease in MLA and an increase in necrotic core. (Harmonizing Outcomes With Revascularization and Stents in Acute Myocardial Infarction [HORIZONS-AMI]; NCT00433966).

Stent thrombosis after primary angioplasty for STEMI in relation to non-adherence to dual antiplatelet therapy over time: results of the HORIZONS-AMI trial

Rates of stent thrombosis (ST) after ST-elevation myocardial infarction (STEMI) may vary over time and the relationship of this complication with non-adherence to dual antiplatelet therapy (DAPT) during long-term follow-up remains unclear. We analysed 2,997 patients who were treated with at least one stent and in whom a non-target vessel ST did not occur during follow-up from the large-scale Harmonizing Outcomes with Revascularization and Stents in Acute Myocardial Infarction (HORIZONS-AMI) trial of patients with STEMI undergoing primary percutaneous coronary intervention (PCI). Aspirin was prescribed indefinitely, and a thienopyridine for at least six months. DAPT usage was evaluated according to the development of ST in four time periods (<1 month, 1-6 months, 6-12 months and >1 year from index stent implantation). DAPT non-usage was lowest within the first month, but was strongly associated with ST. During the 1-6 month period the relationship remained strong, but was absent in the 6-12 month period. Beyond one year, ST was associated with non-usage of aspirin but was paradoxically more common in patients taking a thienopyridine. The relationship between stent thrombosis and non-adherence to DAPT varies over time. It is strong within the first month, remains important until six-month follow-up but fades afterwards. Very late ST is associated with both DAPT and aspirin alone but not with thienopyridine non-adherence.

Safety and Efficacy of High- Versus Low-Dose Aspirin After Primary Percutaneous Coronary Intervention in ST-Segment Elevation Myocardial Infarction: The HORIZONS-AMI (Harmonizing Outcomes With Revascularization and Stents in Acute Myocardial Infarction) Trial

This study sought to examine the relationship between the aspirin dose prescribed at hospital discharge and long-term outcomes after ST-segment elevation myocardial infarction in patients treated with primary percutaneous coronary intervention (PCI). Patients with ST-segment elevation myocardial infarction who undergo primary PCI are prescribed maintenance aspirin doses that vary between 75 and 325 mg daily. Whether the dose of aspirin affects long-term patient outcomes is unknown. We compared 3-year outcomes in patients who were prescribed high-dose (>200 mg daily) versus low-dose (≤200 mg daily) aspirin from the large-scale HORIZONS-AMI (Harmonizing Outcomes With Revascularization and Stents in Acute Myocardial Infarction) trial. Among 2,851 patients, 2,289 patients (80.3%) were discharged on low-dose aspirin and 562 patients (19.7%) were discharged on high-dose aspirin. Patients discharged on high-dose rather than low-dose aspirin were more likely to have a history of hypertension, hyperlipidemia, family history of premature coronary disease, prior treatment with PCI or coronary artery bypass surgery, and to be enrolled in the United States. Patients discharged on high-dose aspirin had higher 3-year rates of major adverse cardiovascular events, reinfarction, ischemic target vessel revascularization, major bleeding, and stent thrombosis. After multivariable analysis, discharge on high-dose aspirin was an independent predictor of major bleeding (hazard ratio: 2.80; 95% confidence interval: 1.31 to 5.99; p = 0.008), but not of adverse ischemic events. In patients with ST-segment elevation myocardial infarction undergoing primary PCI, discharge on high-dose rather than low-dose aspirin may increase the rate of major bleeding without providing additional ischemic benefit.

Characteristics and Outcomes of Patients With ST-Segment Elevation Myocardial Infarction Excluded from the Harmonizing Outcomes With Revascularization and Stents in Acute Myocardial Infarction (HORIZONS-AMI) Trial

Randomized controlled trials assessing new drugs and devices tend to exclude subjects who are at greatest risk. The Harmonizing Outcomes With Revascularization and Stents in Acute Myocardial Infarction (HORIZONS-AMI) trial incorporated broader inclusion criteria in an attempt to include a more representative spectrum of patients presenting with ST-segment elevation myocardial infarction (STEMI). To identify the differences between this modern trial and the real world, we analyzed the characteristics and outcomes of patients with STEMI who were screened but not enrolled at a high-volume recruiting center. Of 318 consecutive patients with STEMI who were screened, 200 (62.9%) were randomized, and 118 (37.1%) were excluded. The baseline characteristics and 30-day and 1-year clinical outcomes were compared in the 2 groups. The excluded patients had numerous high-risk features compared to those randomized, including being older (67.0 ± 12.8 vs 63.0 ± 11.4 years, p= 0.004), more often had had a previous MI (34.7% vs 8.0%, p<0.001), Killip class III-IV (27.4% vs 4.0%, p <0.001), and lower hemoglobin (13.4 ± 2.3 vs 14.8 ± 1.5 g/dl, p <0.001). The excluded patients had markedly greater 30-day and 1-year rates of all-cause mortality (17.4% vs 2.0%, p <0.001, and 27.6% vs 2.5%, p <0.001, respectively), major adverse cardiovascular events (death, MI, ischemia-driven target vessel revascularization, and stroke), major bleeding, and net adverse clinical events (major adverse cardiovascular events or major bleeding). On multivariate analysis, Killip class III-IV at presentation, age, left ventricular ejection fraction, and final Thrombolysis In Myocardial Infarction flow grade 3 were independent predictors of outcome. In conclusion, despite the broadened entry criteria of the HORIZONS-AMI trial, 37.1% of all patients presenting with STEMI at a center with a high rate of enrollment were judged to be ineligible and were excluded. The excluded patients had a significantly greater risk profile andmarkedly increased mortality and adverse events compared to the trial-eligible group.

Clinical Outcomes Following Stent Thrombosis Occurring In-Hospital Versus Out-of-Hospital: Results From the HORIZONS-AMI (Harmonizing Outcomes with Revascularization and Stents in Acute Myocardial Infarction) Trial

The study sought to determine whether rapid access to medical care and reperfusion results in a better prognosis in patients with in-hospital compared with out-of-hospital stent thrombosis (ST) in patients with ST-segment elevation myocardial infarction (STEMI) in the HORIZONS-AMI (Harmonizing Outcomes with Revascularization and Stents in Acute Myocardial Infarction) trial. Whether the prognosis of in-hospital and out-of-hospital ST are similar is uncertain, with conflicting data reported from prior studies. A total of 3,602 STEMI patients undergoing primary percutaneous coronary intervention (PCI) were randomized to bivalirudin (n = 1,800) versus unfractionated heparin (UFH) plus a glycoprotein IIb/IIIa inhibitor (GPI) (UFH+GPI; n = 1,802). Stents were implanted in 3,202 patients, 156 (4.9%) of whom developed Academic Research Consortium definite/probable ST during 3-year follow-up. We investigated the 1-year clinical outcomes after ST in 54 patients with in-hospital ST compared with 102 patients with out-of-hospital ST. One year after the ST event, patients with in-hospital compared with out-of-hospital ST had significantly greater mortality (27.8% vs. 10.8%, p < 0.01); most deaths in both groups occurred within 1 week of the ST event. Patients with in-hospital ST also had higher rates of major bleeding (21.2% vs. 6.0%, p < 0.01), but a lower rate of myocardial infarction (56.6% vs. 77.5%, p < 0.01). Subgroup analysis within both in-hospital and out-of-hospital ST groups indicated that subacute ST had the highest mortality. By multivariable analysis, 1-year mortality was significantly increased in patients with in-hospital compared with out-of-hospital ST (adjusted hazard ratio: 4.62, 95% confidence interval: 1.98 to 10.77, p < 0.01). Additional correlates of increased mortality after an ST event included diabetes and randomization to UFH+GPI (vs. bivalirudin). Following primary PCI for STEMI, more than one-third of all ST events during 3-year follow-up occurred during the index hospital phase. Mortality and major bleeding were significantly higher after in-hospital ST compared with out-of-hospital ST. (Harmonizing Outcomes With Revascularization and Stents in Acute Myocardial Infarction; NCT00433966).

Effect of bivalirudin compared with unfractionated heparin plus abciximab on infarct size and myocardial recovery after primary percutaneous coronary intervention: The horizons‐AMI CMRI substudy

Myocardial infarct size is a strong independent predictor of mortality in patients with ST-elevation myocardial infarction (STEMI). In the Harmonizing Outcomes with RevasculariZatiON and Stents in Acute Myocardial Infarction (HORIZONS-AMI) trial, bivalirudin compared with unfractionated heparin plus a glycoprotein IIb/IIIa inhibitor reduced cardiac mortality in STEMI patients, which was attributed to reduced major bleeding. Whether a possible reduction in infarct size with bivalirudin may have contributed to the enhanced survival with this agent is unknown. Cardiac magnetic resonance imaging was performed within 7 days and after 6 months in 51 randomized patients from a single center in HORIZONS-AMI trial (N = 28 bivalirudin, N = 23 heparin plus abciximab). Infarct size, microvascular obstruction (MVO), left ventricular ejection fraction (LVEF), and LV end-diastolic and end-systolic volume indices were evaluated. Infarct size was not significantly different after treatment with bivalirudin compared with heparin plus abciximab either within 7 days (median 9.3% [interquartile range 4.9%, 26.6%] vs. 20.0% [5.9%, 28.2%], P = 0.28) or at 6 months 6.7% [3.8%, 20.0%] vs. 8.2% [1.8%, 16.5%], P = 0.73). MVO was present in 28.6% versus 34.8% of patients respectively (P = 0.63). LVEF and LV volume indices also did not significantly differ between the two groups at either time period, nor were differences in myocardial recovery evident. In conclusion, in the HORIZONS-AMI Cardiac magnetic resonance imaging (CMRI) substudy, cardiac magnetic resonance imaging within 7 days and at 6 months after primary percutaneous coronary intervention (PCI) did not demonstrate significant differences in infarct size, MVO, LVEF, or LV volume indices in patients treated with bivalirudin compared with unfractionated heparin plus abciximab.

Impact of In-Hospital Major Bleeding on Late Clinical Outcomes After Primary Percutaneous Coronary Intervention in Acute Myocardial Infarction: The HORIZONS-AMI (Harmonizing Outcomes With Revascularization and Stents in Acute Myocardial Infarction) Trial

We aimed to investigate the long-term prognosis of patients with in-hospital major bleeding (IHMB). The effect of IHMB on the long-term prognosis of patients undergoing primary percutaneous coronary intervention (PCI) for ST-segment elevation myocardial infarction is unknown. Primary PCI was performed in 3,345 (92.9%) of 3,602 patients in the HORIZONS-AMI (Harmonizing Outcomes With Revascularization and Stents in Acute Myocardial Infarction) trial; in-hospital protocol-defined non-coronary artery bypass graft-related major bleeding developed in 231 (6.9%). We examined medication use at discharge, mortality, and major adverse cardiovascular events (composite of death, reinfarction, stroke, or ischemic target vessel revascularization) at 3-year follow-up in patients with and without IHMB. At 3-year follow-up, patients with IHMB had higher mortality (24.6% vs. 5.4%, p < 0.0001) and major adverse cardiovascular events (40.3% vs. 20.5%, p < 0.0001). The deleterious effect of major bleeding was observed within 1 month, between 1 month and 1 year, and between 1 and 3 years. IHMB was an independent predictor of mortality (hazard ratio: 2.80; 95% confidence interval: 1.89 to 4.16, p < 0.0001) at 3-year follow up. Patients with IHMB after primary PCI have significantly increased 3-year rates of morbidity and mortality. Further investigation is warranted to understand the mechanisms underlying this relationship and to further improve outcomes in patients with ST-segment myocardial infarction. (Harmonizing Outcomes With Revascularization and Stents in Acute Myocardial Infarction [HORIZONS-AMI]; NCT00433966).

Long-Term Impact of Chronic Kidney Disease in Patients With ST-Segment Elevation Myocardial Infarction Treated With Primary Percutaneous Coronary Intervention: The HORIZONS-AMI (Harmonizing Outcomes With Revascularization and Stents in Acute Myocardial Infarction) Trial

This study sought to investigate the impact of chronic kidney disease (CKD) in patients undergoing percutaneous coronary intervention (PCI) for ST-segment elevation myocardial infarction (STEMI) with different antithrombotic strategies. CKD is associated with increased risk of adverse ischemic and hemorrhagic events after primary PCI for STEMI. HORIZONS-AMI (Harmonizing Outcomes With Revascularization and Stents in Acute Myocardial Infarction) trial was a multicenter, international, randomized trial comparing bivalirudin monotherapy or heparin plus a glycoprotein IIb/IIIa inhibitor (GPI) during primary PCI in STEMI. CKD, defined as creatinine clearance <60 ml/min, was present at baseline in 554 of 3,397 patients (16.3%). Patients were followed for 3 years. Net adverse cardiac event (NACE) was defined as the composite of death, reinfarction, ischemia-driven target vessel revascularization (TVR), stroke or non-coronary artery bypass grafting (CABG)-related major bleeding. Patients with CKD compared with patients without had higher rates of NACE (41.4% vs. 23.8%, p < 0.0001), death (18.7% vs. 4.4%, p < 0.0001), and major bleeding (19.3% vs. 6.7%, p < 0.0001). Multivariable analysis identified baseline creatinine as an independent predictor of death at 3 years (hazard ratio: 1.51, 95% confidence interval: 1.21 to 1.87, p < 0.001). Patients with CKD randomized to bivalirudin monotherapy versus heparin plus GPI had no significant difference in major bleeding (19.0% vs. 19.6%, p = 0.72) or death (19.0% vs. 18.4%, p = 0.88) at 3 years. In patients with CKD, there was no difference in the rates of TVR in bare-metal stents (BMS) versus drug-eluting stents (DES) at 3 years (14.1% vs. 15.1%, p = 0.8). STEMI patients with CKD have significantly higher rates of death and major bleeding compared with those without CKD. In patients with CKD, there appears to be no benefit of bivalirudin compared with heparin + GPI, or DES versus BMS during primary PCI in improving clinical outcomes.

Prognostic Impact of Staged Versus “One-Time” Multivessel Percutaneous Intervention in Acute Myocardial Infarction: Analysis From the HORIZONS-AMI (Harmonizing Outcomes With Revascularization and Stents in Acute Myocardial Infarction) Trial

The purpose of this study was to compare a one-time primary percutaneous coronary intervention (PCI) of the culprit and nonculprit lesions with PCI of only the culprit lesion and staged nonculprit PCI at a later date in patients with ST-segment elevation myocardial infarction (STEMI) and multivessel disease. In patients with STEMI and multivessel disease, it is unknown whether it is safe or even desirable to also treat the nonculprit vessel during the primary PCI procedure. In the HORIZONS-AMI (Harmonizing Outcomes With Revascularization and Stents in Acute Myocardial Infarction) trial, 668 of the 3,602 STEMI patients enrolled (18.5%) underwent PCI of culprit and nonculprit lesions for multivessel disease. Patients were categorized into a single PCI strategy (n = 275) versus staged PCI (n = 393). The endpoints analyzed included the 1-year rates of major adverse cardiovascular events and its components, death, reinfarction, target-vessel revascularization for ischemia, and stroke. Single versus staged PCI was associated with higher 1-year mortality (9.2% vs. 2.3%; hazard ratio [HR]: 4.1, 95% confidence interval [CI]: 1.93 to 8.86, p < 0.0001), cardiac mortality (6.2% vs. 2.0%; HR: 3.14, 95% CI: 1.35 to 7.27, p = 0.005), definite/probable stent thrombosis (5.7% vs. 2.3%; HR: 2.49, 95% CI: 1.09 to 5.70, p = 0.02), and a trend toward greater major adverse cardiovascular events (18.1% vs. 13.4%; HR: 1.42, 95% CI: 0.96 to 2.1, p = 0.08). The mortality advantage favoring staged PCI was maintained in a subgroup of patients undergoing truly elective multivessel PCI. Also, the staged PCI strategy was independently associated with lower all-cause mortality at 30 days and at 1 year. A deferred angioplasty strategy of nonculprit lesions should remain the standard approach in patients with STEMI undergoing primary PCI, as multivessel PCI may be associated with a greater hazard for mortality and stent thrombosis. (Harmonizing Outcomes With Revascularization and Stents in Acute Myocardial Infarction [HORIZONS-AMI]; NCT00433966).

Impact of Diabetes Mellitus on the Safety and Effectiveness of Bivalirudin in Patients With Acute Myocardial Infarction Undergoing Primary Angioplasty: Analysis From the HORIZONS-AMI (Harmonizing Outcomes with RevasculariZatiON and Stents in Acute Myocardial Infarction) Trial

We sought to evaluate the safety and efficacy of bivalirudin compared with glycoprotein IIb/IIIa inhibitors (GPI) in diabetic patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI). Prior studies have demonstrated that GPI are especially beneficial in patients with diabetes with acute coronary syndromes and/or those undergoing PCI. In the multicenter, prospective HORIZONS-AMI (Harmonizing Outcomes with RevasculariZatiON and Stents in Acute Myocardial Infarction) trial, 3,602 patients with STEMI were randomized to bivalirudin or unfractionated heparin plus a GPI. Clinical outcomes were analyzed at 30 days and 1 year in patients with diabetes. Diabetes mellitus was present in 593 patients (16.5%). The rates of cardiac death were significantly lower in diabetic patients treated with bivalirudin compared with heparin plus GPI (30 days: 2.1% vs. 5.5%, p = 0.04; 1 year: 2.5% vs. 7.1%, p = 0.01), and bivalirudin resulted in lower 30-day rates of stroke (0% vs. 2%, p = 0.02). There were no significant differences among diabetic patients randomized to bivalirudin versus heparin plus GPI in the 1-year rates of major adverse cardiac events (14.2% vs. 16.2%, p = 0.44), major bleeding (8.7% vs. 10.7%, p = 0.42), or stent thrombosis (4.2% vs. 3.8%, p = 0.85). By interaction testing, the relative effects of bivalirudin compared with heparin plus GPI were not significantly different in patients with and without diabetes. In patients with diabetes mellitus presenting with STEMI undergoing primary PCI, anticoagulant therapy with bivalirudin compared with heparin plus GPI is safe and effective and might reduce cardiac mortality at 30 days and 1 year. (Harmonizing Outcomes With Revascularization and Stents in Acute Myocardial Infarction; NCT00433966).

Effect of Switching Antithrombin Agents for Primary Angioplasty in Acute Myocardial Infarction: The HORIZONS-SWITCH Analysis

We investigated the outcomes of switching to bivalirudin after initial administration of heparin in patients with acute ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention. Unfractionated heparin (UFH) is frequently administered early in ST-segment elevation myocardial infarction. Whether the benefits of bivalirudin documented in the HORIZONS-AMI (Harmonizing Outcomes With Revascularization and Stents in Acute Myocardial Infarction) trial persist in patients previously administered UFH is unknown. We analyzed the outcomes of the 2,357 patients from HORIZONS-AMI treated with UFH before enrollment according to their subsequent randomization to bivalirudin (switch group, n = 1,178) or UFH plus a glycoprotein IIb/IIIa inhibitor (control group, n = 1,179). At 30 days, major bleeding occurred in 7.6% of the switch group versus 12.3% of the control group (p = 0.0001). Switch patients had lower 30-day rates of cardiac mortality (1.6% vs. 2.9%, p = 0.04). At 2-year follow-up, switch patients experienced lower rates of major bleeding (8.4% vs. 13.0%, p = 0.0003), cardiac mortality (2.3% vs. 3.8%, p = 0.04), and reinfarction (4.0% vs. 7.1%, p = 0.0002). Two-year rates of definite/probable stent thrombosis were similar in switch and control patients (3.1% vs. 4.3%, p = 0.17). In ST-segment elevation myocardial infarction patients who receive early treatment with UFH, switching to bivalirudin before primary percutaneous coronary intervention results in reduced rates of major bleeding and improved early and late cardiac survival.

The Relationship Between Attenuated Plaque Identified by Intravascular Ultrasound and No-Reflow After Stenting in Acute Myocardial Infarction: The HORIZONS-AMI (Harmonizing Outcomes With Revascularization and Stents in Acute Myocardial Infarction) Trial

The aim of this study was to understand the impact of attenuated plaque on distal embolization during stent implantation in patients with acute myocardial infarction (AMI). Attenuated plaques identified by grayscale intravascular ultrasound (IVUS) might predict transient deterioration in coronary flow and/or no-reflow during percutaneous coronary intervention (PCI). We analyzed clinical, angiographic, and IVUS data from 364 patients (n = 364 infarct-related arteries) enrolled in the randomized HORIZONS-AMI (Harmonizing Outcomes With Revascularization and Stents in Acute Myocardial Infarction) trial. No-reflow was final Thrombolysis In Myocardial Infarction (TIMI) flow grade ≤2 in the absence of mechanical obstruction. Attenuated plaque was hypoechoic or mixed atheroma with ultrasound attenuation without calcification. A mean attenuation score was created by measuring the angle of attenuation each 1 mm, scoring the angle as 1 to 4 (corresponding to <90°, 90° to 180°, 180° to 270°, or 270° to 360°, respectively), summing the scores, and normalizing for analysis length. Overall, 284 (78.0%) patients had attenuated plaques; no-reflow occurred in 37 (10.2%). Patients with no-reflow had a higher mean attenuation score (median [interquartile range] 2.2 [0.0 to 2.8] vs. 1.3 [0.7 to 1.8], p < 0.001), lower baseline left ventricular ejection fraction (52.8% [43.2% to 61.5%] vs. 61.4% [52.2% to 68.1%], p = 0.002), and more baseline angiographic thrombus (89.2% vs. 74.1%, p = 0.043) with no differences in post-PCI stent expansion versus patients without no-reflow. Multivariate analysis indicated that mean attenuation score was the strongest predictor of no-reflow. The mean attenuation score that best predicted no-reflow was ≥2 points (90° to 180°, sensitivity of 81.5%, and specificity of 80.5%). Attenuated plaque was present in three-quarters of patients with AMI. The amount of attenuated plaque strongly correlated with no-reflow; the larger the attenuated plaque, the greater the likelihood of no-reflow. (Dual Arm Factorial Randomized Trial in Patients w/ST Segment Elevation AMI to Compare the Results of Using Anticoagulation With Either Unfractionated Heparin + Routine GP IIb/IIIa Inhibition or Bivalirudin + Bail-out GP IIb/IIIa Inhibition; and Primary Angioplasty with stent implantation with Either a Slow Rate-release Paclitaxel-eluting Stent [TAXUS™] or Uncoated Bare Metal Stent [EXPRESS2™]; NCT00433966).

Paclitaxel-Eluting Stents Compared With Bare Metal Stents in Diabetic Patients With Acute Myocardial Infarction

Background— In the prospective, randomized Harmonizing Outcomes with Revascularization and Stents in Acute Myocardial Infarction (HORIZONS-AMI) trial, implantation of paclitaxel-eluting stents (PES) safely reduced the rates of ischemic target lesion revascularization (TLR) compared with bare metal stents (BMS) in patients with ST-segment–elevation myocardial infarction (STEMI) undergoing primary percutaneous intervention. Diabetes mellitus is a known predictor of adverse outcomes after percutaneous intervention in STEMI. We therefore sought to assess the impact of PES in diabetic patients with STEMI from the HORIZONS-AMI trial. Methods and Results— A total of 478 patients with diabetes and 2527 without diabetes were randomly assigned to receive PES versus BMS. The 12-month rates of ischemic TLR were significantly reduced by PES compared with BMS in both diabetic (11.2% versus 5.2%; hazard ratio [95% confidence interval]=0.45 [0.21 to 0.93]; P =0.03) and nondiabetic (6.8% versus 4.3%, hazard ratio [95% confidence interval]=0.63 [0.44 to 0.92]; P =0.02) patients. In patients with insulin-treated diabetes, PES compared with BMS reduced the 12-month TLR rate from 21.4% to 7.3% (hazard ratio [95% confidence interval]=0.35 [0.12 to 1.03]; P =0.046). Angiographic late loss and binary restenosis at 13 months were also significantly reduced in PES-treated diabetic patients. There were no significant differences between the BMS and PES groups in the 12-month rates of death, reinfarction, stroke, or stent thrombosis in either diabetic or nondiabetic patients. Conclusions— In the large-scale, prospective, randomized HORIZONS-AMI trial, implantation of PES compared with BMS in patients with STEMI and diabetes mellitus resulted in significant reductions in ischemia-driven TLR and angiographic restenosis at 1 year, with comparable safety outcomes, including stent thrombosis. These results suggest that PES can safely be used to reduce restenosis in high-risk diabetic patients presenting with STEMI. Clinical Trial Registration— URL: http://www.clinicaltrials.gov . Unique identifier: NCT00433966.