Low stent thrombosis risk with the XIENCE V® Everolimus-Eluting Coronary Stent: evidence from randomized and single-arm clinical trials.

The XIENCE V® Everolimus-Eluting Coronary Stent System (EECSS) has been evaluated in multiple randomized controlled trials (RCTs) with several different comparators (SPIRIT FIRST, SPIRIT II, SPIRIT III, SPIRIT IV, COMPARE, ISAR-TEST 4, SORT-OUT IV, and RESOLUTE All-Comers RCT). The available results consistently demonstrated numerically low stent thrombosis (ST) rates in the XIENCE V arm treated patients. The use of XIENCE V in complex patients with diabetes, overlapping stents, multistenting, and other known risk factors has not significantly increased the occurrence of ST, as evident in the 2-year rates of both per protocol and Academic Research Consortium (ARC)-defined ST rates in the SPIRIT IV RCT, as well as the COMPARE real-world RCT. Furthermore, available long-term follow-up in the SPIRIT FIRST, SPIRIT II, and SPIRIT III RCTs showed continued numerically low very late ST rates as well. High compliance rates of dual antiplatelet therapy (DAPT) were observed in the SPIRIT trials, which may have contributed to consistently numerically low ST rates in the XIENCE V arm treated patients. Several potential risk factors for developing ST may well have been minimized through the selective XIENCE V thin strut design, biocompatible polymers, and antiproliferative drug usage. (J Interven Cardiol 2011;24:326-341).

Performance of everolimus-eluting versus paclitaxel-eluting coronary stents in small vessels: results from the SPIRIT III and SPIRIT IV clinical trials.

BACKGROUND: Higher rates of adverse cardiac events have been observed in patients with small vessel disease. Therefore, we compared an everolimus-eluting stent (EES) to a paclitaxel-eluting stent (PES) for treatment of small (reference vessel diameter: RVD <2.5 mm) and larger vessels (≥2.5 mm) in a pooled analysis from the SPIRIT III (n = 1,002) and SPIRIT IV (n = 3,687) trials (randomized 2:1, EES vs. PES). METHODS: Data of 4,689 total patients were pooled for a patient level analysis. Lesion length, RVD, and percent diabetics were matched between stent types. EES versus PES performance was evaluated at 1 year in patients with small (n = 1,019) and larger vessels (n = 2,586) who had a single lesion treated. RESULTS: Mean RVD assessed by quantitative coronary angiography in patients with small vessels was 2.24 ± 0.19 and 2.25 ± 0.20 mm in the EES and PES groups, respectively. At 1 year, EES compared to PES in small vessel patients significantly reduced major adverse cardiac events (4.5% vs. 7.9%, P = 0.04), target lesion failure (4.4% vs. 7.9%, P = 0.03), target lesion revascularization (2.4% vs. 5.5%, P = 0.02), and stent thrombosis (0.2% vs. 1.2%, P = 0.04). Relative benefits of EES versus PES were comparable in small and larger vessels (P interaction > 0.05), although the absolute benefits were greater in patients with small vessel disease. CONCLUSION: In high-risk patients requiring percutaneous coronary intervention in small coronary arteries, EES results in significantly improved 1-year rates of event-free survival compared to PES, with evidence present for both enhanced safety and efficacy.

Evaluation of XIENCE V everolimus-eluting and Taxus Express2 paclitaxel-eluting coronary stents in patients with jailed side branches from the SPIRIT IV trial at 2 years.

The aim of this study was to determine whether patients from the Clinical Evaluation of the XIENCE V Everolimus Eluting Coronary Stent System in the Treatment of Patients With de Novo Native Coronary Artery Lesions (SPIRIT) IV trial who underwent percutaneous coronary intervention, who had target lesions with jailed side branches, had improved clinical outcomes when treated with the XIENCE V versus Taxus Express(2) drug-eluting stent. In the SPIRIT III randomized trial, patients with target lesions with jailed side branches after XIENCE V compared with Taxus Express(2) implantation had lower 2-year rates of major adverse cardiac events. The SPIRIT IV trial represents a larger more diverse patient population compared with SPIRIT III. In the large-scale, prospective, multicenter, randomized SPIRIT IV trial, 3,687 patients who underwent coronary stenting with up to 3 de novo native coronary artery lesions were randomized 2:1 to receive XIENCE V versus Taxus Express(2) stents. Two-year clinical outcomes of patients with or without jailed side branches after stenting were compared. A jailed side branch was defined as any side branch >1.0 mm in diameter within the target segment being stented, excluding bifurcations deemed to require treatment. Of the 3,687 patients in SPIRIT IV, a total of 1,426 had side branches that were jailed during angioplasty of the target lesion. Patients with jailed side branches after XIENCE V compared with Taxus Express(2) implantation had significantly lower 2-year rates of target lesion failure (6.5% vs 11.9%, p = 0.001), major adverse cardiac events (6.6% vs 12.2%, p = 0.0008), ischemia-driven target vessel revascularization (4.1% vs 7.9%, p = 0.004), and stent thrombosis (0.6% vs 2.8%, p = 0.001). In conclusion, patients with jailed side branches after stenting with XIENCE V compared to Taxus Express(2) devices had superior clinical outcomes at 2 years in the large-scale randomized SPIRIT IV trial.

Predictors of early and late outcomes after everolimus and paclitaxel-eluting coronary stents.

AIMS: To evaluate whether the improved outcomes with newer generation drug-eluting stents (DES) utilising thin-strut stents are consistent among different patient and angiographic subgroups. METHODS AND RESULTS: Clinical outcomes over three years were collected in the SPIRIT III trial comparing the XIENCE V® everolimus-eluting stents (EES) (Abbott Vascular, Santa Clara, CA, USA) to the TAXUS® paclitaxel-eluting stents (PES) (Boston Scientific, Natick, MA, USA). Potential predictors of adverse clinical outcomes were assessed using demographic, clinical, and procedural variables by logistic and Cox regression analyses. For three-year target vessel failure, the independent predictors identified by Cox regression were number of vessels treated (HR=2.19 [1.50, 3.19], p<0.0001), HbA1c (%) (HR=1.17 [1.05, 1.29], p=0.004), total cholesterol (>200 mg/dl) (HR=1.63 [1.13, 2.36], p=0.009), and female gender (HR=1.42 [1.01, 2.01], p=0.05). Logistic regression analysis identified the same predictors except for the female gender. The clinical results with EES compared to PES were consistent among the multiple subgroups examined with the possible exception of patients with diabetes. CONCLUSIONS: Clinical factors and stent type were the most important multivariable predictors of adverse clinical outcomes in this contemporary trial of first versus second generation DES. The benefit of the EES compared to the PES was consistent across a wide range of patient and angiographic subgroups with the possible exception of patients with diabetes.

Impact of routine angiographic follow-up after percutaneous coronary intervention with drug-eluting stents in the SPIRIT III randomized trial at three years.

Routine angiographic follow-up after bare-metal stent implantation has been associated with an increase in coronary revascularization. The impact of angiographic follow-up after drug-eluting stent placement remains poorly characterized. The prospective, randomized, single-blinded SPIRIT III trial assigned patients to the everolimus-eluting stent or the paclitaxel-eluting stent (PES). Major adverse cardiovascular events (cardiac death, myocardial infarction, and ischemia-driven target lesion revascularization [ID-TLR]) at 3 years were assessed by angiographic versus clinical-only follow-up at 8 months ± 28 days and a landmark survival analysis from 9 months to 3 years. Of 1,002 patients, 564 patients were assigned to angiographic follow-up at 8 months ± 28 days and 438 patients underwent clinical follow-up alone. Three-year major adverse cardiovascular event rates were 10.6% in the angiographic group and 12.0% in the clinical follow-up group (p = 0.64). Ischemia-driven revascularization increased twofold at 9 months, but no difference was noted in ID-TLR for either device. Non-ID-TLR was significantly higher in patients in the angiographic group (4.5% vs 1.0%, p = 0.002), a difference resulting from PES (9.1% vs 0.7%, p = 0.0007) rather than everolimus-eluting stent (2.2% vs 1.1%, p = 0.36) treatment. The landmark analysis showed no significant differences between the angiographic and clinical follow-up groups from 9 months to 3 years of major clinical outcomes. In conclusion, routine angiographic follow-up in SPIRIT III did not increase rates of ID-TLR compared to clinical follow-up alone. Despite higher nonischemia-driven revascularization rates with angiographic follow-up of patients with PESs, none of the safety end points were adversely affected.

Periprocedural myocardial infarction in a randomized trial of everolimus-eluting and Paclitaxel-eluting coronary stents: frequency and impact on mortality according to historic versus universal definitions.

BACKGROUND: A consensus definition for periprocedural myocardial infarction (MI) in coronary stent trials has not been established. Differences between a historic definition, based on modified World Health Organization (WHO) criteria, and a proposed universal definition have not been compared in a prospective clinical trial. METHODS AND RESULTS: We randomly assigned 3687 patients with stable coronary artery disease to undergo stenting with either everolimus-eluting stents (2458 patients) or paclitaxel-eluting stents (1229 patients). Serial creatine kinase (CK) and CKMB or troponin measurements were obtained before and after stenting. MI was classified by protocol according to the WHO definition (total CK >2× normal with elevated CKMB) and post hoc according to the Universal/Academic Research Consortium (ARC) definition (CKMB or troponin >3× normal). Protocol MI was determined in 58 (1.6%) and universal/ARC MI in 287 (7.8%) patients within 48 hours post index procedure. There were substantial differences in frequency of universal/ARC MI if only CKMB (5.4%) or troponin (18.7%) data were included for evaluation. Total stent length was a strong predictor of both protocol and universal/ARC MI. Mortality at 2 years was low (2.3%) and was not different for either MI definition. The mortality rates did not increase with elevations of CKMB or troponin to >10× normal. CONCLUSIONS: There was a marked difference in periprocedural MI rates according to protocol or universal/ARC MI definitions. No association was present between periprocedural MI and mortality up to 2 years by either definition. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00307047.

Impact of age on clinical outcomes after everolimus-eluting and paclitaxel-eluting stent implantation: pooled analysis from the SPIRIT III and SPIRIT IV clinical trials.

AIMS: The impact of age on outcomes following everolimus-eluting stent (EES) or paclitaxel-eluting stent (PES) implantation was evaluated in a patient-level pooled analysis of the SPIRIT III (n=1,002) and SPIRIT IV (n=3,687) trials. METHODS AND RESULTS: Clinical outcomes with EES compared to PES in elderly (≥ 65 years, n=2,071) and younger (<65 years, n=2,617) patients were evaluated at one year. At one year, elderly patients treated with EES rather than PES showed a significant reduction in target lesion failure (TLF) (3.9% EES vs. 6.8% PES, p=0.006), major adverse cardiac events (MACE) (4.0% EES vs. 7.1% PES, p=0.005), and ischaemia-driven target lesion revascularisation (ID-TLR) (2.0% EES vs. 4.0% PES, p=0.01). Younger patients treated with EES rather than PES also had significantly reduced one-year rates of TLF (4.9% EES vs. 7.9% PES, p=0.003), MACE (5.0% EES vs. 8.0% PES, p=0.004), target vessel myocardial infarction (MI) (2.0% EES vs. 3.4% PES, p=0.04), ID-TLR (3.3% EES vs. 5.5% PES, p=0.01) and stent thrombosis (0.5% EES vs. 1.6% PES, p=0.01). CONCLUSIONS: In a pooled analysis from the SPIRIT III and IV trials, EES was safer and more effective than PES in both younger and older cohorts as evidenced by lower rates of TLR, TLF and MACE.

Clinical and angiographic outcomes of elderly patients treated with everolimus-eluting versus paclitaxel-eluting stents: three-year results from the SPIRIT III randomised trial.

AIMS: Age is an important determinant of outcomes in patients treated with percutaneous coronary intervention (PCI). This report from the randomised multicentre SPIRIT III trial compares the outcomes in elderly and younger patients treated with everolimus-eluting stent (EES) versus paclitaxel-eluting stent (PES). METHODS AND RESULTS: A total of 1,002 patients with stable or unstable angina or inducible ischaemia undergoing PCI were randomised in a 2:1 ratio to receive EES or PES. Outcomes were examined across the randomised groups as a function of age and stent type. Patients ≥65 years of age (elderly) treated with EES vs. PES had lower in-segment late lumen loss (0.11±0.32 mm vs. 0.38±0.55 mm, respectively, p=0.0002) and lower rates of binary in-segment restenosis (3.4% vs. 15.5%, p = 0.004) at eight months, along with a 48% lower incidence of 3-year target vessel failure (TVF=cardiac death, myocardial infarction and ischaemia-driven target vessel revascularisation [TVR]; 10.8% vs. 20.8%, p=0.009), mainly due to a lower incidence of TVR (5.4% vs. 9.2%, p=0.20). Among EES patients, elderly compared to younger patients had comparable rates of binary in-segment restenosis (3.4% vs. 5.6%, p=0.44) at eight months but paradoxically lower rates of TVF (10.8% vs. 17.1%, p=0.03) at three years. Among PES patients, elderly compared to younger patients had a higher rate of binary in-segment restenosis (15.5% vs. 3.4%, p=0.01) at eight months and no difference in the rate of 3-year TVF (20.8% vs. 19.4%, p=0.77) .There was a significant interaction between stent assignment, age ≥65 years and 8-month angiographic in-segment late loss (p=0.001). CONCLUSIONS: Implantation of both EES and PES appeared to be safe in elderly patients, however EES compared to PES was more effective due to enhanced 3-year MACE- and TVF-free outcomes. Further research should clarify age-specific mechanisms of neointimal response after treatment with drug-eluting stents.

Three-year results of safety and efficacy of the everolimus-eluting coronary stent in women (from the SPIRIT III randomized clinical trial).

Women treated with the XIENCE V have improved 1-year clinical outcomes compared to women treated with TAXUS; whether benefits in women are sustained at 3 years is unknown. Three-year follow-up of the SPIRIT III trial revealed improved clinical outcomes of the XIENCE V everolimus-eluting stent compared to the TAXUS paclitaxel-eluting stent. One thousand two patients with coronary artery lesions ≤28 mm in length in 2.5- to 3.75-mm diameter vessels were prospectively randomized to receive XIENCE V or TAXUS stents. A post hoc gender subset analysis was performed. Six hundred sixty-nine patients (30% women) received XIENCE V and 332 patients (34% women) received TAXUS. In the overall population, women had higher 3-year rates of major adverse cardiac events (16.0% vs 10.0%, p = 0.01) and target lesion revascularization (10.2% vs 5.3%, p = 0.008) compared to men. In women, those with XIENCE V continued to have lower major adverse cardiac event rates than those with TAXUS at 2 years (9.5% vs 18.3%, p = 0.03) and 3 years (12.2% vs 22.6%, p = 0.03). Although 1-year target vessel failure rates were similar, at 2- and 3-year follow-up women treated with XIENCE V had approximately 40% relative decreases in target vessel failure rates compared to those treated with TAXUS (12.7% vs 22.0%, p = 0.05; 16.0% vs 26.4%, p = 0.03, respectively). Stent thrombosis and bleeding complication rates were similar between treatment arms in the gender subgroups through 3 years. In conclusion, women in the SPIRIT III trial have sustained clinical benefits from XIENCE V implantation compared to TAXUS without increases in long-term complications.

Long-term (three-year) safety and efficacy of everolimus-eluting stents compared to paclitaxel-eluting stents (from the SPIRIT III Trial).

The safety and efficacy of the XIENCE V everolimus-eluting stent (EES) compared to the Taxus Express(2) paclitaxel-eluting stent (PES) has been demonstrated through 2 years in the SPIRIT II and III randomized clinical trials, but limited longer-term data have been reported. In the SPIRIT III trial, 1,002 patients with up to 2 lesions in 2 coronary arteries were randomized 2:1 to EESs versus PESs at 65 United States sites. At completion of 3-year follow-up, treatment with EES compared to PES resulted in a significant 30% decrease in the primary clinical end point of target vessel failure (cardiac death, myocardial infarction, or ischemic-driven target vessel revascularization, 13.5% vs 19.2%, hazard ratio 0.70, 95% confidence interval 0.50 to 0.96, p = 0.03) and a 43% decrease in major adverse cardiovascular events, cardiac death, myocardial infarction, or ischemic-driven target lesion revascularization (9.1% vs 15.7%, hazard ratio 0.57, 95% confidence interval 0.39 to 0.83, p = 0.003). In a landmark analysis, major adverse cardiovascular events were decreased to a similar extent with EES compared to PES 0 through 1 year and 1 year through 3 years (hazard ratio 0.56, 95% confidence interval 0.35 to 0.90; hazard ratio 0.59, 95% confidence interval 0.31 to 1.11, respectively). In conclusion, patients treated with EES rather than PES in the SPIRIT III trial had significantly improved event-free survival at 3 years. From 1 year to 3 years hazard curves continued to diverge in favor of EES, consistent with an improving long-term safety and efficacy profile of EES compared to PES, with no evidence of late catchup.

Clinical follow-up 3 years after everolimus- and paclitaxel-eluting stents: a pooled analysis from the SPIRIT II (A Clinical Evaluation of the XIENCE V Everolimus Eluting Coronary Stent System in the Treatment of Patients With De Novo Native Coronary Artery Lesions) and SPIRIT III (A Clinical Evaluation of the Investigational Device XIENCE V Everolimus Eluting Coronary Stent System [EECSS] in the Treatment of Subjects With De Novo Native Coronary Artery Lesions) randomized trials.

OBJECTIVES: The purpose of this study was to investigate long-term 3-year clinical outcomes of an everolimus-eluting stent (EES) versus a paclitaxel-eluting stent (PES). BACKGROUND: Compared with PES, EES reduced target vessel failure and major adverse cardiac events at 2 years. Whether the benefits of EES are sustained at 3 years has not been reported. METHODS: In the SPIRIT II (A Clinical Evaluation of the XIENCE V Everolimus Eluting Coronary Stent System in the Treatment of Patients With De Novo Native Coronary Artery Lesions) and SPIRIT III (A Clinical Evaluation of the Investigational Device XIENCE V Everolimus Eluting Coronary Stent System [EECSS] in the Treatment of Subjects With De Novo Native Coronary Artery Lesions) trials, 1,302 patients were randomly assigned to EES (n = 892) or PES (n = 410). We report the 3-year clinical follow-up of this patient-level pooled analysis. RESULTS: At 3 years, EES compared with PES resulted in a significant reduction in myocardial infarction (3.8% vs. 6.7%; relative risk [RR]: 0.56; 95% confidence interval [CI]: 0.34 to 0.94; p = 0.04), and target lesion revascularization (6.8% vs. 12.7%; RR: 0.53; 95% CI: 0.37 to 0.77; p = 0.001). Everolimus-eluting stents resulted in a significant reduction in target vessel failure (13.7% vs. 19.5%; RR: 0.70; 95% CI: 0.54 to 0.92; p = 0.01), and major adverse cardiac events (9.1% vs. 16.3%; RR: 0.56; 95% CI: 0.41 to 0.76; p = 0.0004). The cumulative rates of Academic Research Consortium-defined definite or probable stent thrombosis were 1.2% in EES patients and 1.9% in PES patients (RR: 0.64; 95% CI: 0.25 to 1.68; p = 0.43). CONCLUSIONS: In this patient-level pooled analysis, EES compared with PES resulted in a significant and persistent reduction in target vessel failure and major adverse cardiac events at 3 years due to fewer myocardial infarction and ischemic target lesion revascularization events, which is consistent with superior safety and efficacy of the EES platform.

Comparison of everolimus-eluting and paclitaxel-eluting coronary stents in patients undergoing multilesion and multivessel intervention: the SPIRIT III (A Clinical Evaluation of the Investigational Device XIENCE V Everolimus Eluting Coronary Stent System [EECSS] in the Treatment of Subjects With De Novo Native Coronary Artery Lesions) and SPIRIT IV (Clinical Evaluation of the XIENCE V Everolimus Eluting Coronary Stent System in the Treatment of Subjects With De Novo Native Coronary Artery Lesions) randomized trials.

OBJECTIVES: We evaluated outcomes following XIENCE V everolimus-eluting stent (EES) compared with the Taxus Express(2) paclitaxel-eluting stent (PES) in patients undergoing multilesion and multivessel intervention. BACKGROUND: The optimal revascularization strategy for patients with multivessel disease is unknown. METHODS: The SPIRIT III (A Clinical Evaluation of the Investigational Device XIENCE V Everolimus Eluting Coronary Stent System [EECSS] in the Treatment of Subjects With De Novo Native Coronary Artery Lesions) (n = 1,002) and SPIRIT IV (Clinical Evaluation of the XIENCE V Everolimus Eluting Coronary Stent System in the Treatment of Subjects With De Novo Native Coronary Artery Lesions) (n = 3,690) trials enrolled patients with de novo lesions ≤ 28 mm in length and reference vessel diameter of 2.5 to 3.75 mm. The SPIRIT III trial enrolled patients with a single lesion in 1 or 2 coronary arteries, and the SPIRIT IV trial enrolled patients with up to 2 lesions in 3 different vessels (maximum 2 lesions per vessel). In both trials, patients were randomized 2:1 to EES vs. PES. Clinical outcomes to 1 year were analyzed in patients with single (n = 3,823) versus multiple (n = 765) treated vessels, and in those with single (n = 3,536) versus multiple (n = 1,052) treated lesions. RESULTS: Among patients with multivessel disease, EES compared with PES resulted in reduced rates of target vessel myocardial infarction (2.2% vs. 6.1%, p = 0.007) and ischemia-driven target lesion revascularization (4.2% vs. 8.0%, p = 0.04). Among patients undergoing multilesion stenting, EES compared with PES resulted in reduced rates of target vessel myocardial infarction (2.1% vs. 5.4%, p = 0.008) and ischemia-driven target lesion revascularization (3.7% vs. 7.4%, p = 0.01). The absolute benefits of EES versus PES in patients undergoing multivessel or multilesion intervention were greater than in those undergoing single-lesion, single-vessel intervention. CONCLUSIONS: The EES compared with PES provided significant improvements in clinical safety and efficacy outcomes. The absolute benefit provided by EES versus PES appears to be proportional to the complexity of coronary disease.

Outcomes in diabetic and nondiabetic patients treated with everolimus- or paclitaxel-eluting stents: results from the SPIRIT IV clinical trial (Clinical Evaluation of the XIENCE V Everolimus Eluting Coronary Stent System).

OBJECTIVES: We compared the safety and efficacy of the XIENCE V (Abbott Vascular, Santa Clara, California) everolimus-eluting stent (EES) with the TAXUS Express (Boston Scientific, Natick, Massachusetts) paclitaxel-eluting stent (PES) among the large cohort of randomized diabetic patients enrolled in the SPIRIT IV (Clinical Evaluation of the XIENCE V Everolimus Eluting Coronary Stent System) trial. BACKGROUND: Diabetes mellitus remains a significant predictor of adverse clinical outcomes after percutaneous coronary intervention with drug-eluting stents, and the comparative outcomes of different drug-eluting stents in diabetic patients remains ill-defined. METHODS: In the SPIRIT IV trial, 3,687 patients with up to 3 de novo native coronary artery lesions were prospectively randomized 2:1 to receive EES or PES. Randomization was stratified by the presence of diabetes and lesion complexity. The primary end point was the occurrence of target lesion failure (TLF) (cardiac death, target-vessel myocardial infarction, or ischemia-driven target lesion revascularization) at 1 year. Clinical outcomes were evaluated in randomized diabetic (n = 1,185 [786 EES; 399 PES]) and nondiabetic patients (n = 2,498 [1,669 EES; 829 PES]). RESULTS: The EES compared with PES reduced TLF in nondiabetic patients (3.1% vs. 6.7%, p < 0.0001), with significant reductions in myocardial infarction, stent thrombosis, and target lesion revascularization. In contrast, no difference in TLF (6.4% vs. 6.9%, respectively, p = 0.80) or any of its components was present among diabetic patients, regardless of insulin use. A significant interaction between the presence of diabetes and stent type on TLF (p(interaction) = 0.02) was observed. CONCLUSIONS: In the SPIRIT IV randomized trial, EES compared with PES provided similar clinical outcomes in diabetic patients and superior clinical outcomes in nondiabetic patients at 1 year. (SPIRIT IV Clinical Trial: Clinical Evaluation of the XIENCE V Everolimus Eluting Coronary Stent System in the Treatment of Subjects With de Novo Native Coronary Artery Lesions; NCT00307047).

Side branch occlusion with everolimus-eluting and paclitaxel-eluting stents: three-year results from the SPIRIT III randomised trial.

AIMS AND METHODS: The rates of side branch occlusion and subsequent periprocedural MI during everolimus-eluting stent (EES) and paclitaxel-eluting stent (PES) placement were examined in the randomised SPIRIT III trial. Periprocedural myocardial infarction (MI) following drug-eluting stent placement is associated with long-term adverse outcomes. Occlusion of side branches may be an important factor contributing to periprocedural MIs. Consecutive procedural angiograms of patients randomly assigned to EES (n=669) or PES (n=333) were analysed by an independent angiographic core laboratory. Side branch occlusion was defined as Thrombolysis In Myocardial Infarction (TIMI) flow grade 0 or 1. Clinical outcomes through three years were compared by stent type and presence of side branch occlusion. CONCLUSIONS: A total of 2,048 side branches were evaluated (EES N=1,345 side branches in 688 stented lesions, PES N=703 side branches in 346 stented lesions). Patients with compared to those without transient or final side branch occlusion had significantly higher non-Q-wave MI (NQMI) rates in-hospital (9.0% vs. 0.5%, p<0.0001). By multivariable analysis side branch occlusion was an independent predictor of NQMI (OR 4.45; 95% CI [1.82, 10.85]). Transient or final side branch occlusion occurred less frequently in patients receiving EES compared to PES (2.8% vs. 5.2%, p=0.009), contributing to the numerically lower rates of in-hospital NQMI with EES arm compared to PES (0.7% vs. 2.3%, p=0.05). Patients treated with EES rather than PES were less likely to develop side branch occlusion during stent placement, contributing to lower rates of periprocedural MI with EES compared to PES.