Anesthetic and Airways Management of a Dog with Severe Tracheal Collapse during Intraluminal Stent Placement

This case report describes the anesthetic and airways management of a dog affected by 4th degree tracheal collapse and undergoing endoscope-guided intraluminal stent placement. After premedication with acepromazine and butorphanol, general anesthesia was induced with propofol and maintained with intravenous propofol and butorphanol in constant rate infusion. During intraluminal stent placement, oxygen was supplemented by means of a simple and inexpensive handmade device, namely, a ureteral catheter inserted into the trachea and connected to an oxygen source, which allowed for the maintenance of airways’ patency and adequate patient’s oxygenation, without decreasing visibility in the surgical field or interfering with the procedure. The use of the technique described in the present paper was the main determinant of the successful anesthetic management and may be proposed for similar critical cases in which surgical manipulation of the tracheal lumen, which may potentially result in hypoxia by compromising airways patency, is required.

Impact of stent overlap on long-term clinical outcomes in patients treated with newer-generation drug-eluting stents

Aims: Early-generation drug-eluting stent (DES) overlap (OL) is associated with impaired long-term clinical outcomes whereas the impact of OL with newer-generation DES is unknown. Our aim was to assess the impact of OL on long-term clinical outcomes among patients treated with newer-generation DES. Methods and results: We analysed the three-year clinical outcomes of 3,133 patients included in a prospective DES registry according to stent type (sirolimus-eluting stents [SES; N=1,532] versus everolimus-eluting stents [EES; N=1,601]), and the presence or absence of OL. The primary outcome was a composite of death, myocardial infarction (MI), and target vessel revascularisation (TVR). The primary endpoint was more common in patients with OL (25.1%) than in those with multiple DES without OL (20.8%, adj HR=1.46, 95% CI: 1.03-2.09) and patients with a single DES (18.8%, adj HR=1.74, 95% CI: 1.34-2.25, p<0.001) at three years. A stratified analysis by stent type showed a higher risk of the primary outcome in SES with OL (28.7%) compared to other SES groups (without OL: 22.6%, p=0.04; single DES: 17.6%, p<0.001), but not between EES with OL (22.3%) and other EES groups (without OL: 18.5%, p=0.30; single DES: 20.4%, p=0.20). Conclusions: DES overlap is associated with impaired clinical outcomes during long-term follow-up. Compared with SES, EES provide similar clinical outcomes irrespective of DES overlap status.

Comparison of Newer-Generation Drug-Eluting With Bare-Metal Stents in Patients With Acute ST-Segment Elevation Myocardial Infarction: A Pooled Analysis of the EXAMINATION (clinical Evaluation of the Xience-V stent in Acute Myocardial INfArcTION) and COMFORTABLE-AMI (Comparison of Biolimus Eluted From an Erodible Stent Coating With Bare Metal Stents in Acute ST-Elevation Myocardial Infarction) Trials

OBJECTIVES This study sought to study the efficacy and safety of newer-generation drug-eluting stents (DES) compared with bare-metal stents (BMS) in an appropriately powered population of patients with ST-segment elevation myocardial infarction (STEMI). BACKGROUND Among patients with STEMI, early generation DES improved efficacy but not safety compared with BMS. Newer-generation DES, everolimus-eluting stents, and biolimus A9-eluting stents, have been shown to improve clinical outcomes compared with early generation DES. METHODS Individual patient data for 2,665 STEMI patients enrolled in 2 large-scale randomized clinical trials comparing newer-generation DES with BMS were pooled: 1,326 patients received a newer-generation DES (everolimus-eluting stent or biolimus A9-eluting stent), whereas the remaining 1,329 patients received a BMS. Random-effects models were used to assess differences between the 2 groups for the device-oriented composite endpoint of cardiac death, target-vessel reinfarction, and target-lesion revascularization and the patient-oriented composite endpoint of all-cause death, any infarction, and any revascularization at 1 year. RESULTS Newer-generation DES substantially reduce the risk of the device-oriented composite endpoint compared with BMS at 1 year (relative risk [RR]: 0.58; 95% confidence interval [CI]: 0.43 to 0.79; p = 0.0004). Similarly, the risk of the patient-oriented composite endpoint was lower with newer-generation DES than BMS (RR: 0.78; 95% CI: 0.63 to 0.96; p = 0.02). Differences in favor of newer-generation DES were driven by both a lower risk of repeat revascularization of the target lesion (RR: 0.33; 95% CI: 0.20 to 0.52; p < 0.0001) and a lower risk of target-vessel infarction (RR: 0.36; 95% CI: 0.14 to 0.92; p = 0.03). Newer-generation DES also reduced the risk of definite stent thrombosis (RR: 0.35; 95% CI: 0.16 to 0.75; p = 0.006) compared with BMS. CONCLUSIONS Among patients with STEMI, newer-generation DES improve safety and efficacy compared with BMS throughout 1 year. It remains to be determined whether the differences in favor of newer-generation DES are sustained during long-term follow-up.

Flow disturbances in stent-related coronary evaginations: a computational fluid-dynamic simulation study

Aims: Angiographic ectasias and aneurysms in stented segments have been associated with late stent thrombosis. Using optical coherence tomography (OCT), some stented segments show coronary evaginations reminiscent of ectasias. The purpose of this study was to explore, using computational fluid-dynamic (CFD) simulations, whether OCT-detected coronary evaginations can induce local changes in blood flow. Methods and results: OCT-detected evaginations are defined as outward bulges in the luminal vessel contour between struts, with the depth of the bulge exceeding the actual strut thickness. Evaginations can be characterised cross ectionally by depth and along the stented segment by total length. Assuming an ellipsoid shape, we modelled 3-D evaginations with different sizes by varying the depth from 0.2-1.0 mm, and the length from 1-9 mm. For the flow simulation we used average flow velocity data from non-diseased coronary arteries. The change in flow with varying evagination sizes was assessed using a particle tracing test where the particle transit time within the segment with evagination was compared with that of a control vessel. The presence of the evagination caused a delayed particle transit time which increased with the evagination size. The change in flow consisted locally of recirculation within the evagination, as well as flow deceleration due to a larger lumen - seen as a deflection of flow towards the evagination. Conclusions: CFD simulation of 3-D evaginations and blood flow suggests that evaginations affect flow locally, with a flow disturbance that increases with increasing evagination size.

Clinical outcomes of the resolute zotarolimus-eluting stent in patients with in-stent restenosis: 2-year results from a pooled analysis

OBJECTIVES This study sought to assess the clinical safety and effectiveness of the Resolute zotarolimus-eluting stent (R-ZES) in patients with in-stent restenosis (ISR) from 2 large trials. BACKGROUND ISR treatment is associated with higher rates of subsequent cardiac events compared with treatment of de novo lesions. Although drug-eluting stents (DES) are an option, second-generation DES are largely untested in the treatment of ISR. METHODS A total of 3,489 patients were pooled from the RAC (RESOLUTE All Comers) trial and the RESOLUTE International (RINT) registry. Two-year clinical endpoints included clinically driven target lesion revascularization (TLR), target lesion failure (TLF), cardiac death (CD), target vessel myocardial infarction (TVMI), combined CD or TVMI (CD/TVMI), and Academic Research Consortium definite and probable stent thrombosis (ST). RESULTS Overall, 281 patients (8.1%) received an R-ZES for ISR. Two-year TLR and TLF rates were significantly higher in ISR patients than in non-ISR patients (TLR: 12.7% vs. 4.3%, p = 0.003; TLF: 17.4% vs. 9.4%, p = 0.007); however, the CD/TVMI rate was not (6.9% vs. 6.1%, p = 0.711). Seven ISR patients had ST. Two-year outcomes by ISR stent type were similar: bare-metal stent (BMS)-ISR TLR was 12.5% and TLF was 17.2%; DES-ISR TLR was 13.0% and TLF was 18.8%. CD/TVMI was 7.3% and 7.2% for BMS-ISR and DES-ISR, respectively. CONCLUSIONS Using R-ZES to treat ISR appears equally safe in BMS-ISR and DES-ISR, with CD/TVMI rates comparable to 2-year outcomes in other clinical trials. Although revascularization rates are still higher in ISR lesions, the R-ZES offers an effective alternative for treatment of BMS-ISR and DES-ISR. (Randomized, Two-Arm, Non-inferiority Study Comparing Endeavor-Resolute Stent With Abbot Xience-V Stent [RESOLUTE-AC]; NCT00617084; and RESOLUTE International Registry: Evaluation of the Resolute Zotarolimus-Eluting Stent System in a 'Real-World' Patient Population [RINT]; NCT00752128).

Clinical outcomes after zotarolimus and everolimus drug eluting stent implantation in coronary artery bifurcation lesions: insights from the RESOLUTE All Comers Trial

OBJECTIVE We investigated clinical outcomes after treatment of coronary bifurcation lesions with second generation drug eluting stents (DES). DESIGN Post hoc analysis of a randomised, multicentre, non-inferiority trial. SETTING Multicentre study. PATIENTS All comers study with minimal exclusion criteria. INTERVENTIONS Patients were treated with either zotarolimus or everolimus eluting stents. The patient population was divided according to treatment of bifurcation or non-bifurcation lesions and clinical outcomes were compared between groups. MAIN OUTCOMES MEASURES Clinical outcomes within 2-year follow-up. RESULTS A total of 2265 patients were included in the present analysis. Two-year follow-up data were available in 2223 patients: 1838 patients in the non-bifurcation group and 385 patients in the bifurcation group. At 2-year follow-up the bifurcation and the non-bifurcation lesion groups showed no significant differences in terms of cardiac death (2.3 vs 2.1, p=0.273), target lesion failure (9.7% vs 13.8%, p=0.255), major adverse cardiac events (11.5% vs 15.1%, p=0.305), target lesion revascularisation (4.7% vs 6.0%, p=0.569), and definite or probable stent thrombosis (1.6% vs 1.8%, p=0.419). CONCLUSIONS The use of second generation DES for the treatment of coronary bifurcation lesions was associated with similar long term mortality and clinical outcomes compared with non-bifurcation lesions.

The edge vascular response following implantation of the Absorb everolimus-eluting bioresorbable vascular scaffold and the XIENCE V metallic everolimus-eluting stent. First serial follow-up assessment at six months and two years: insights from the first-in-man ABSORB Cohort B and SPIRIT II trials

AIMS To assess serially the edge vascular response (EVR) of a bioresorbable vascular scaffold (BVS) compared to a metallic everolimus-eluting stent (EES). METHODS AND RESULTS Non-serial evaluations of the Absorb BVS at one year have previously demonstrated proximal edge constrictive remodelling and distal edge changes in plaque composition with increase of the percent fibro-fatty (FF) tissue component. The 5 mm proximal and distal segments adjacent to the implanted devices were investigated serially with intravascular ultrasound (IVUS), post procedure, at six months and at two years, from the ABSORB Cohort B1 (n=45) and the SPIRIT II (n=113) trials. Twenty-two proximal and twenty-four distal edge segments were available for analysis in the ABSORB Cohort B1 trial. In the SPIRIT II trial, thirty-three proximal and forty-six distal edge segments were analysed. At the 5-mm proximal edge, the vessels treated with an Absorb BVS from post procedure to two years demonstrated a lumen loss (LL) of 6.68% (-17.33; 2.08) (p=0.027) with a trend toward plaque area increase of 7.55% (-4.68; 27.11) (p=0.06). At the 5-mm distal edge no major changes were evident at either time point. At the 5-mm proximal edge the vessels treated with a XIENCE V EES from post procedure to two years did not show any signs of LL, only plaque area decrease of 6.90% (-17.86; 4.23) (p=0.035). At the distal edge no major changes were evident with regard to either lumen area or vessel remodelling at the same time point. CONCLUSIONS The IVUS-based serial evaluation of the EVR up to two years following implantation of a bioresorbable everolimus-eluting scaffold shows a statistically significant proximal edge LL; however, this finding did not seem to have any clinical implications in the serial assessment. The upcoming imaging follow-up of the Absorb BVS at three years is anticipated to provide further information regarding the vessel wall behaviour at the edges.

Clinical outcome of patients with and without diabetes mellitus after percutaneous coronary intervention with the resolute zotarolimus-eluting stent: 2-year results from the prospectively pooled analysis of the international global RESOLUTE program

OBJECTIVES The aim of this study was to describe the process to obtain Food and Drug Administration (FDA) approval for the expanded indication for treatment with the Resolute zotarolimus-eluting stent (R-ZES) (Medtronic, Inc., Santa Rosa, California) in patients with coronary artery disease and diabetes. BACKGROUND The R-ZES is the first drug-eluting stent specifically indicated in the United States for percutaneous coronary intervention in patients with diabetes. METHODS We pooled patient-level data for 5,130 patients from the RESOLUTE Global Clinical Program. A performance goal prospectively determined in conjunction with the FDA was established as a rate of target vessel failure at 12 months of 14.5%. In addition to the FDA pre-specified cohort of less complex patients with diabetes (n = 878), we evaluated outcomes of the R-ZES in all 1,535 patients with diabetes compared with all 3,595 patients without diabetes at 2 years. RESULTS The 12-month rate of target vessel failure in the pre-specified diabetic cohort was 7.8% (upper 95% confidence interval: 9.51%), significantly lower than the performance goal of 14.5% (p < 0.001). After 2 years, the cumulative incidence of target lesion failure in patients with noninsulin-treated diabetes was comparable to that of patients without diabetes (8.0% vs. 7.1%). The higher risk insulin-treated population demonstrated a significantly higher target lesion failure rate (13.7%). In the whole population, including complex patients, rates of stent thrombosis were not significantly different between patients with and without diabetes (1.2% vs. 0.8%). CONCLUSIONS The R-ZES is safe and effective in patients with diabetes. Long-term clinical data of patients with noninsulin-treated diabetes are equivalent to patients without diabetes. Patients with insulin-treated diabetes remain a higher risk subset. (The Medtronic RESOLUTE Clinical Trial; NCT00248079; Randomized, Two-arm, Non-inferiority Study Comparing Endeavor-Resolute Stent With Abbot Xience-V Stent [RESOLUTE-AC]; NCT00617084; The Medtronic RESOLUTE US Clinical Trial (R-US); NCT00726453; RESOLUTE International Registry: Evaluation of the Resolute Zotarolimus-Eluting Stent System in a 'Real-World' Patient Population [R-Int]; NCT00752128; RESOLUTE Japan-The Clinical Evaluation of the MDT-4107 Drug-Eluting Coronary Stent [RJ]; NCT00927940).

One-year head to head comparison of the neointimal response between sirolimus eluting stent with reservoir technology and everolimus eluting stent: an optical coherence tomography study

OBJECTIVE to compare the vascular healing process between the sirolimus-eluting NEVO and the everolimus-eluting Xience stent by optical coherence tomography (OCT) at 1-year follow-up. BACKGROUND Presence of durable polymer on a drug-eluting metallic stent may be the basis of an inflammatory reaction with abnormal healing response. The NEVO stent, having a bioresorbable polymer eluted by reservoir technology, may overcome this problem. METHODS All consecutive patients, who received NEVO or Xience stent implantation between September 2010 and October 2010 in our institution, were included. Vascular healing was assessed at 1-year as percentage of uncovered struts, neointimal thickness (NIT), in-stent/stent area obstruction and pattern of neointima. RESULTS A total 47 patients (2:1 randomization, n = 32 NEVO, n = 15 Xience) were included. Eighteen patients underwent angiographic follow-up (eight patients with nine lesions for NEVO vs. 10 patients with 11 lesions for Xience). The angiographic late loss was numerically higher but not statistically different in NEVO compared with Xience treated lesions (0.38 ± 0.47 mm vs. 0.18 ± 0.27 mm; P = 0.171). OCT analysis of 4,912 struts demonstrated similar rates of uncovered struts (0.5 vs. 0.7%, P = 0.462), higher mean NIT (177.76 ± 87.76 µm vs. 132.22 ± 30.91 µm; P = 0.170) and in stent/stent area obstruction (23.02 ± 14.74% vs. 14.17 ± 5.94%, P = 0.120) in the NEVO as compared with Xience. CONCLUSION The NEVO stent with a reservoir technology seems to exhibit more neointimal proliferation as compared to Xience stent. The findings of our study, which currently represent the unique data existing on this reservoir technology, would need to be confirmed in a large population.

New approach to direct stenting using a novel "all-in-one" coronary stent system via 5 French diagnostic catheters: a pilot study

OBJECTIVES We sought to evaluate the strategy success and short term clinical outcomes of direct stenting via 5 French (F) diagnostic catheters using a novel bare metal stent with integrated delivery system (IDS) (Svelte Medical Systems, New Providence, NJ) and compare the results to a conventionally treated matched group. METHODS Fifteen consecutive patients with lesions deemed suitable for direct stenting using a bare metal stent were included. The primary endpoint was the strategy success defined as the ability to successfully treat a target lesion via a 5 F diagnostic catheter with a good angiographic result (TIMI III flow, residual stenosis ≤20%). Procedure and fluoroscopy times, contrast agent use, cost, and short-term clinical outcomes were compared to a matched group treated via conventional stenting. RESULTS The primary endpoint was reached in 14/15 patients (93%). There were no significant differences in procedural (58.6 min ± 12.7 vs. 57.4 min ± 14.2) or fluoroscopy times (10.0 min ± 4.3 vs.10.1 min ± 3.9) or contrast agent use (193.7 ml ± 54.8 vs. 181.4 ml ± 35.6). However, there were significant reductions in materials used in the study group compared to the control group equating to cost savings of almost US $600 per case (US $212.44 ± 258.09 vs. US $804.69 ± 468.11; P = 0.001). CONCLUSIONS Direct stenting using a novel bare metal stent with an IDS via 5 F diagnostic catheters is a viable alternative to conventional stenting in selected patients and is associated with significant cost savings.

Natural history of optical coherence tomography-detected non-flow-limiting edge dissections following drug-eluting stent implantation

Aims: Angiographic evidence of edge dissections has been associated with a risk of early stent thrombosis. Optical coherence tomography (OCT) is a high-resolution technology detecting a greater number of edge dissections -particularly non-flow-limiting- compared to angiography. Their natural history and clinical implications remain unclear. The objectives of the present study were to assess the morphology, healing response, and clinical outcomes of OCT-detected edge dissections using serial OCT imaging at baseline and at one year following drug-eluting stent (DES) implantation. Methods and results: Edge dissections were defined as disruptions of the luminal surface in the 5 mm segments proximal and distal to the stent, and categorised as flaps, cavities, double-lumen dissections or fissures. Qualitative and quantitative OCT analyses were performed every 0.5 mm at baseline and one year, and clinical outcomes were assessed. Sixty-three lesions (57 patients) were studied with OCT at baseline and one-year follow-up. Twenty-two non-flow-limiting edge dissections in 21 lesions (20 patients) were identified by OCT; only two (9%) were angiographically visible. Flaps were found in 96% of cases. The median longitudinal dissection length was 2.9 mm (interquartile range [IQR] 1.6-4.2 mm), whereas the circumferential and axial extensions amounted to 1.2 mm (IQR: 0.9-1.7 mm) and 0.6 mm (IQR: 0.4-0.7 mm), respectively. Dissections extended into the media and adventitia in seven (33%) and four (20%) cases, respectively. Eighteen (82%) OCT-detected edge dissections were also evaluated with intravascular ultrasound which identified nine (50%) of these OCT-detected dissections. No stent thrombosis or target lesion revascularisation occurred up to one year. At follow-up, 20 (90%) edge dissections were completely healed on OCT. The two cases exhibiting persistent dissection had the longest flaps (2.81 mm and 2.42 mm) at baseline. Conclusions: OCT-detected edge dissections which are angiographically silent in the majority of cases are not associated with acute stent thrombosis or restenosis up to one-year follow-up.

Neoatherosclerosis as reason for stent failures beyond 5 years after drug-eluting stent implantation

A 69-year-old male (case 1) was admitted due to acute non-ST-segment elevation myocardial infarction (NSTEMI). Eight years earlier, he had previously undergone treatment with a sirolimus-eluting stent (SES). Four years after stent implantation, a follow-up angiography was obtained showing a patent stent without obstructive in-stent restenosis (Panel A). Angiograms obtained at the time of NSTEMI (Panel B) disclosed subtotal occlusion in the middle of the SES (arrowheads). Optical coherence tomography revealed a signal intense luminal layer with an underlying, highly attenuating, diffusely demarcated area, suggestive for an instent fibroatheroma (Panel D) with a minimal cap thickness of 80 µm. Accordingly, ischaemia was caused by the high degree of stenosis (Panel E). Similarly, a 59-year-old male (case 2) was admitted due to STEMI. Nine years before, he had received a paclitaxel-eluting stent (PES). Five years after stent implantation, a follow-up angiography revealed a patent stent (Panel F). Angiograms obtained at the time of STEMI (Panel G) disclosed total occlusion in the proximal of PES (arrowheads). Optical coherence tomography showed a rupture of thin cap fibroatheroma within the stented segment (Panel I). The thin cap fibroatheroma caused a severe stenosis with superimposed thrombus (Panel J). Neoatherosclerosis has been recently described as particular disease entity being responsible for very late stent failures. These two cases illustrate that the presence of a favourable long-term angiographic result years after DES implantation does not exclude a future neoatherosclerosis-related event (restenosis or stent thrombosis). Large observational and long-term intracoronary imaging studies are required to fully elucidate the dynamics and clinical relevance of neoatherosclerosis.

The effects of thoracic epidurally administered drugs on urethral sphincter function in women: a pooled analysis

OBJECTIVES Thoracic epidural analgesia (TEA) has been shown to inhibit detrusor activity in patients undergoing open renal surgery, resulting in clinically relevant post-void residuals. However, the impact of different epidural drug mixtures on urethral sphincter function is not completely elucidated. DESIGN Pooled analysis of an open observational study and a double-blind randomized trial. SETTING Single tertiary centre. SUBJECTS Twenty-eight women without lower urinary tract symptoms and post-void residual <100 mL, who underwent open renal surgery with TEA. METHODS Pooling results in three groups with different epidural regimens (7 with bupivacaine 0.125%, 8 with bupivacaine 0.125% and fentanyl 2 μg/mL, and 13 with bupivacaine 0.1% plus fentanyl 2 μg/mL and epinephrine 2 μg/mL). All women underwent urethral pressure measurements before TEA and during TEA 2-3 days postoperatively. All patients received a TEA placed at the insertion site interspace T 8-9. RESULTS Maximum urethral closure pressure at rest decreased significantly during TEA with bupivacaine alone (median 70 cm H2 O [interquartile range 66-76] to 43 [43-65], P = 0.031) and with bupivacaine/fentanyl/epinephrine (75 cm H2 O [68-78] to 56 [52-75], P = 0.028), whereas with bupivacaine/fentanyl, no significant change could be detected (74 [51-88] vs 67 [46-70], P = 0.156). In all groups, functional profile length at rest was not influenced during TEA. CONCLUSION TEA with bupivacaine and the addition of fentanyl and epinephrine appears to decrease maximum urethral closure pressure at rest in women. The addition of fentanyl alone to bupivacaine may reduce this effect. Thus, the TEA effect on urethral sphincter function seems to depend on the drug mixture administered.

Stent thrombosis with ticagrelor versus clopidogrel in patients with acute coronary syndromes: an analysis from the prospective, randomized PLATO trial

BACKGROUND We aimed to describe the effects of ticagrelor versus clopidogrel on stent thrombosis in the Platelet Inhibition and Patient Outcomes (PLATO) trial. METHODS AND RESULTS Of 18 624 patients hospitalized for acute coronary syndromes, 11 289 (61%) had at least 1 intracoronary stent. Ticagrelor reduced stent thrombosis compared with clopidogrel across all definitions: definite, 1.37% (n=71) versus 1.93% (n=105; hazard ratio [HR], 0.67; 95% confidence interval [CI], 0.50-0.90; P=0.0091); definite or probable, 2.21% (n=118) versus 2.87% (n=157; HR, 0.75; 95% CI, 0.59-0.95; P=0.017); and definite, probable, and possible, 2.94% (n=154) versus 3.77 (n=201; HR, 0.77; 95% CI, 0.62-0.95). The reduction in definite stent thrombosis was consistent regardless of acute coronary syndrome type, presence of diabetes mellitus, stent type (drug-eluting or bare metal stent), CYP2C19 genetic status, loading dose of aspirin, dose of clopidogrel before randomization, and use of glycoprotein IIb/IIIa inhibitors at randomization. The reduction in stent thrombosis with ticagrelor was numerically greater for late (>30 days; HR, 0.48; 95% CI, 0.24-0.96) and subacute (4 hours-30 days; HR, 0.60; 95% CI, 0.39-0.93) compared with acute (<24 hours; HR, 0.94; 95% CI, 0.43-2.05) stent thrombosis or for patients compliant to therapy (ie, taking blinded study treatment ≥80% of the time) compared with less compliant patients. Randomization to ticagrelor was a strong independent inverse predictor of definite stent thrombosis (HR, 0.65; 95% CI, 0.48-0.88). CONCLUSION Ticagrelor compared with clopidogrel reduces the incidence of stent thrombosis in patients with acute coronary syndromes, with consistent benefit across a broad range of patient, stent, and treatment characteristics.