Duration of dual antiplatelet therapy and associated outcomes following percutaneous coronary intervention for acute myocardial infarction: contemporary practice insights from the Canadian Observational Antiplatelet Study.

Aims: There is a paucity of real-world, contemporary data of practice patterns and clinical outcomes following dual-antiplatelet therapy (DAPT) in acute myocardial infarction (AMI) patients treated with percutaneous coronary intervention (PCI). Methods and results: The Canadian Observational Antiplatelet Study was a prospective, multicentre, cohort study examining adenosine diphosphate receptor antagonist use following PCI for AMI. We compared practice patterns, patient characteristics, and clinical outcomes in relation to DAPT duration (<6 weeks, 6 weeks to <6 months, 6 to <12, and ≥12 months). The primary outcome was the composite of non-fatal AMI, unplanned coronary revascularization, stent thrombosis, new or worsening heart failure, cardiogenic shock, or stroke. We identified 2034 patients with AMI treated with PCI. DAPT duration was <6 weeks in 5.2% of patients; 6 weeks to <6 months in 7.0%; 6 to <12 months in 12.6%; and ≥12 months in 75.3%. Patients who discontinued DAPT early had higher GRACE risk scores. Overall, mortality rate at 15 months was 2.5%. Compared with a duration of DAPT of ≥12 months, discontinuation of DAPT <6 weeks (P < 0.0001) and 6 weeks to <6 months (P = 0.02), but not 6 months to <12 months (P = 0.06), were independently associated with a higher incidence of the primary outcome among survivors. Conclusion: One-in-four patients with AMI treated with PCI discontinued DAPT prior to the guideline-recommended 12-month duration. Patients in whom DAPT was discontinued early were at higher baseline risk and had higher rates of non-fatal ischaemic events during follow up.

Long-term outcomes following drug-eluting stents versus bare metal stents for primary percutaneous coronary intervention: A real-world analysis of 11,181 patients from the british columbia cardiac registry.

BACKGROUND: Drug eluting stents (DES) are associated with reduced risk of restenosis when compared with bare metal stents (BMS). Their use in ST-elevation myocardial infarction (STEMI) is debated, owing to concerns about stent thrombosis. There are limited real-world data comparing DES versus BMS in STEMI. We conducted an observational analysis in this setting and rigorously adjusted for treatment selection bias. METHODS: We analyzed 11,181 consecutive patients with acute STEMI who received either DES or BMS during 2008-2014 in the British Columbia Cardiac Registry. We analyzed target vessel revascularization (TVR) and mortality at 2 years. RESULTS: Multivariable-adjusted, propensity-matched and inverse probability-treatment weighted analyses found DES to be associated with early and late survival up to 2 years but not TVR. However, when adjusting for measured and unmeasured confounders, instrumental variable (IV) analyses demonstrated that DES use was associated with reduced TVR up to 2 years (Δ = -6.7%, 95% CI: -10.0%, -3.4%, P < 0.001). DES use was not associated with mortality at 1 year (Δ = -2.3%, 95% CI: -5.0%, 0.4%, P = 0.100) but associated with reduced mortality at 2 years (Δ = -5.4%, 95% CI: -8.3%, -2.5%, P < 0.001). Stratified IV analyses indicated that this long-term survival benefit was largely attributable to the second generation DES. CONCLUSIONS: In this study of patients with STEMI, when adjusting for measured and unmeasured factors, DES use was associated with reduced TVR and long-term survival beyond 1 year. This long-term survival was largely attributable to the second generation DES. These real-world data are reassuring and support the use of DES for STEMI. © 2016 Wiley Periodicals, Inc.

Prolonged Clopidogrel Use is Associated with Improved Clinical Outcomes Following Drug-Eluting But Not Bare Metal Stent Implantation.

BACKGROUND: Guidelines recommend clopidogrel use for 6-12 months following drug-eluting stent (DES) implantation and 1-12 months following bare metal stent (BMS) implantation. The role of clopidogrel beyond 12 months is unclear. METHODS: We linked hospital administrative, community pharmacy and cardiac revascularization data to determine clopidogrel use and outcomes for all patients (those with acute presentations and those with stable angina) receiving a coronary stent in British Columbia 2004-2006, with follow-up until the end of 2008. Cox proportional hazard regression was performed to evaluate the effect of clopidogrel duration (≤12 vs. >12 months) on outcomes following BMS or DES implantation. Patients who died ≤12 months from index stent placement were excluded. RESULTS: A total of 15,629 patients were included in the study. Of 3599 patients who received at least one DES and 12,030 patients who received only BMS, 1326 (37 %) and 2121 (18 %), respectively, filled a prescription for clopidogrel >12 months from the index procedure. The mean duration of clopidogrel was 406 ± 35 days and 407 ± 37 days in the prolonged use (>12 months) DES and BMS cohorts, respectively, compared with 224 ± 112 days (p < 0.001) and 122 ± 117 days (p < 0.001), respectively, for patients receiving clopidogrel ≤12 months. Clopidogrel use beyond 12 months was associated with a reduction in mortality [hazard ratio (HR) 0.66, 95 % confidence interval (CI) 0.45-0.97] and the composite of mortality and readmission for myocardial infarction (HR 0.72, 95 % CI 0.55-0.94) in patients treated with DES, but not BMS alone. Prolonged clopidogrel use was not associated with bleeding-related mortality. CONCLUSIONS: Clopidogrel use beyond 12 months was associated with a reduction in death and hospitalization for myocardial infarction following DES, but not BMS, implantation. Our findings support a longer duration of clopidogrel therapy for patients treated with DES.

Delay in filling first clopidogrel prescription after coronary stenting is associated with an increased risk of death and myocardial infarction.

BACKGROUND: Patients frequently experience difficulties with medication compliance after hospital discharge. We investigated the effect of a delay in filling a first clopidogrel prescription after hospital discharge on clinical outcomes subsequent to coronary stenting. METHODS AND RESULTS: Hospital administrative, community pharmacy, and cardiac revascularization data were determined for all patients receiving a coronary stent in British Columbia 2004-2006 with follow-up out to 2 years. Cox's proportional hazard regression analysis, adjusting for baseline demographics and procedural variables, was performed to examine the effects of delay in filling a clopidogrel prescription after hospital discharge on clinical outcomes.Of 15 629 patients treated with coronary stents, 3599 received at least 1 drug-eluting stent (DES), whereas 12 030 received bare metal stents (BMS) alone. In total, 1064 (30%) and 3758 (31%) patients in the DES and BMS groups, respectively, failed to fill a prescription within 3 days of discharge (median, 1 day; interquartile range [IQR], 1 to 3). After regression analysis, a delay of >3 days was predictive of mortality and recurrent myocardial infarction (MI) irrespective of stent type (DES: hazard ratio [HR], 2.4; 95% confidence interval [CI], 1.7 to 3.4; and HR, 2.0; 95% CI, 1.5 to 2.7, respectively, and BMS: HR, 2.2; 95% CI, 1.9 to 2.6; and HR, 1.8; 95% CI, 1.5 to 2.1, respectively). This excess hazard was greatest in the 30-day period immediately after hospital discharge (mortality: HR, 5.5; 95% CI, 3.5 to 8.6; and MI: HR, 3.1; 95% CI, 2.4 to 4.0, for all patients). CONCLUSIONS: Delays in patients filling their first prescription for clopidogrel after coronary stenting are common and associated with adverse clinical outcomes, irrespective of stent type. Strategies to reduce delays have the potential to improve clinical outcomes.

Non-red blood cell transfusion as a risk factor for mortality following percutaneous coronary intervention.

BACKGROUND: Bleeding following percutaneous coronary intervention (PCI) is common and may lead to transfusion and death. Although previous work has examined the effect of red blood cell (RBC) transfusion in patients with coronary disease, no study had investigated whether transfusion of non-RBC components was associated with mortality following PCI. METHODS: All subjects transfused in the 10 days following PCI were identified using the British Columbia Cardiac and Central Transfusion Registries. Patients undergoing cardiac surgery following PCI were excluded as transfusion was assumed to be due to surgical related bleeding. Transfusion products were categorised as RBC and non-RBC comprising platelets, plasma and cryoprecipitate. Blood product use was compared according to thirty day mortality using multivariate regression and propensity adjustment for confounding variables. RESULTS: From a total of 32,580 patients who underwent PCI, 952 patients received at least 1 blood product within 10 days of PCI. Non-RBC transfusion occurred more commonly in the cohort of transfused patients dying within 30 days (p<0.001). After adjustment for baseline risk, transfusion of plasma/cryoprecipitate (HR 5.17; 95% C.I. 2.87-9.32, p<0.001) and platelets (HR 2.13; 95% C.I. 1.10-4.13, p=0.03) was associated with increased 30 day mortality. In a propensity risk adjusted model, transfusion of plasma/cryoprecipitate and RBC transfusion volume remained as significant predictors of 30-day mortality (p<0.001). CONCLUSIONS: Transfusion following PCI appears to be associated with an increased risk of death within 30 days. We now report that transfusion with plasma rich non-RBC products may confer an additional mortality risk to patients undergoing PCI.

Red blood cell storage duration and mortality in patients undergoing percutaneous coronary intervention.

BACKGROUND: Blood transfusion has been associated with an increased mortality in patients undergoing percutaneous coronary intervention (PCI). Although the reasons for this remain unclear, it may be related to the structural and functional changes occurring within red blood cells (RBCs) during storage. We investigated whether RBC storage duration was associated with mortality in patients requiring transfusion after PCI. METHODS: We collected data on all RBC transfusions occurring within 10 days of PCI (excluding those related to cardiac surgery) using the British Columbia Cardiac Registry and Central Transfusion Registry. Transfusion details were analyzed according to 30-day survival. RESULTS: From a total of 32,580 patients undergoing PCI, 909 (2.8%) patients received RBCs with a mean storage duration of 25 +/- 10 days. In these 909 patients, mean transfusion volumes were lower in survivors (2.8 +/- 2.1 vs 3.8 +/- 2.9 U, P = .002) than those who died within 30 days. In a multivariate analysis to adjust for baseline risk, mean RBC storage age (HR 1.02 [95% CI 1.01-1.04], P = .002) and transfusion volume (HR 1.26 [95% CI 1.18-1.34], P < .001) both predicted 30-day mortality. Transfused patients who received only older blood (RBC min age >28 days) appeared to be at greater risk of death (HR 2.49 [95% CI 1.45-4.25], P = .001). CONCLUSION: Red blood cell transfusion is associated with increased 30-day mortality in patients undergoing PCI. Although current transfusion practice permits RBC storage for up to 42 days, the use of older red cells may pose an additional hazard to this patient group.