Outcomes in Patients Stratified by PRECISE-DAPT Versus DAPT Scores After Percutaneous Coronary Interventions

The optimal length of dual antiplatelet therapy (DAPT) after percutaneous coronary intervention (PCI) remains debated. Current guidelines recommend individualized treatment with consideration of risk scores. We sought to evaluate the degree of agreement in treatment recommendations and the ability to predict ischemic and bleeding complications of the PRECISE-DAPT (predicting bleeding complications in patients undergoing stent implantation and subsequent dual antiplatelet therapy) and DAPT scores. Consecutive patients receiving 12 months of DAPT were grouped based on score treatment recommendation at the time of PCI: PRECISE-DAPT prolonged or shortened (PRECISE DAPT <25 vs ≥25) and DAPT prolonged or shortened (DAPT ≥2 vs <2). One-year ischemic and bleeding outcomes were compared for each group. In 451 patients, the PRECISE-DAPT and DAPT score recommendations were concordant in 56.7% of patients (Cohen's kappa for agreement of k = 0.139, 95% confidence interval 0.065 to 0.212). There was no difference in composite major adverse cardiovascular and cerebrovascular events between patients with high versus low PRECISE-DAPT or DAPT scores. In patients with a high PRECISE-DAPT score versus a low score, there was an increased incidence of 1-year all-cause mortality (2.13% vs 0%, p = 0.04) and an increase in bleeding (Bleeding Academic Research Consortium ≥3a: 17.0% vs 2.8%; p <0.001; Bleeding Academic Research Consortium 3b/c and 5: 8.5% vs 1.4%; p = 0.001). There were no differences in rates of mortality or bleeding for patients with high versus low DAPT scores. In conclusion, when applied at the baseline, the PRECISE-DAPT and DAPT scores frequently make discordant DAPT duration recommendations. The PRECISE-DAPT, but not the DAPT score, demonstrated associations with all-cause mortality and bleeding in patients prescribed 12 months of DAPT after PCI.

Antithrombotic Therapy After Percutaneous Coronary Intervention in Patients With Atrial Fibrillation: Findings From the CONNECT AF+PCI Study

Background

In patients with atrial fibrillation (AF) undergoing percutaneous coronary intervention (PCI), selecting an antithrombotic regimen requires balancing risks of ischemic cardiac events, stroke, and bleeding.

Methods

We studied 467 patients with AF undergoing PCI in the time period from December 2015 to July 2018 identified via a chart audit by 47 Canadian cardiologists in the CONNECT AF+PCI (the Coordinated National Network to Engage Interventional Cardiologists in the Antithrombotic Treatment of Patients With Atrial Fibrillation Undergoing Percutaneous Coronary Intervention) study, to determine patterns of initial antithrombotic therapy selection.

Results

The median (25th, 75th percentile) CHADS₂ score was 2 (1, 3), and PCI was performed in the setting of acute coronary syndrome in 62.1%. Triple antithrombotic therapy (TAT) was the initial treatment in 62.7%, dual-pathway therapy in 25.7%, and dual antiplatelet therapy in 11.6%, with a temporal increase in use of dual-pathway therapy during the course of the study; median intended TAT duration was 1 (1, 3) month. Compared with patients selected for TAT, patients selected for dual-pathway therapy were less likely to have prior myocardial infarction (35.8% vs 25.8%, P = 0.045) and prior PCI (33.8% vs 23.3%, P = 0.03), and they received shorter total length of stents (38 [23, 56] vs 30 [20, 46] mm, P = 0.03). Patients selected for dual-pathway therapy had a higher prevalence of prior stroke/transient ischemic attack (13.0% vs 23.3%, P = 0.01). There was no difference in prevalence of anemia (21.5% vs 25.8%, P = 0.30). Use of dual-pathway therapy was similar among patients with acute coronary syndrome and those with stable disease (24.1% vs 28.2%, P = 0.32).

Conclusions

Approximately one-quarter of AF patients undergoing PCI are treated with dual-pathway therapy in Canadian practice, with its use increasing during the studied period. Patients selected for dual-pathway therapy have less-complex coronary disease history and intervention.

Implications of the Antiplatelet Therapy Gap Left With Discontinuation of Prasugrel in Canada

Background

The current Canadian Cardiovascular Society antiplatelet therapy guidelines recommend the use of ticagrelor or prasugrel over clopidogrel as first-line platelet P2Y12 receptor antagonists for treatment of moderate- to high-risk acute coronary syndromes. Recently, Effient (prasugrel [Eli Lilly Canada Inc, Toronto, Canada]) was discontinued by its distributor in Canada.

Methods

Five members of the Canadian Cardiovascular Society antiplatelet therapy 2018 guidelines committee undertook an independent, evidence-based review to outline patients for whom prasugrel should be the optimal P2Y12 agent and discuss alternative strategies to consider without prasugrel.

Results

Several clinical scenarios where prasugrel should be indicated are identified and discussed. Considerations to be undertaken for alternative therapies are summarized, including a review of national and international guidelines for de-escalation of P2Y12 receptor antagonists.

Conclusions

The discontinuation of prasugrel poses a challenge for clinicians. Clinicians must consider key factors in determining the best alternate therapy.

Delays in ST-Elevation Myocardial Infarction Care During the COVID-19 Lockdown: An Observational Study

BACKGROUND

Management of ST-elevated myocardial infarction (STEMI) necessitates rapid reperfusion. Delays prolong myocardial ischemia and increase the risk of complications, including death. The COVID-19 pandemic may have impacted STEMI management. We evaluated the relative volume of hospitalizations and clinical time intervals within a regional STEMI system.

METHODS

494 patients with STEMI were grouped into pre-lockdown, lockdown and re-opening cohorts. Clinical, temporal and outcome data were collected and compared between groups for both urban and rural patients, receiving primary percutaneous coronary intervention (PCI) and pharmacoinvasive revascularization, respectively. Data was compared to a 10-year historical comparator.

RESULTS

During pre-lockdown there was 238 cases versus 193 in lockdown; a 19.0% reduction in volume. When lockdown was compared to the median caseload from a 10-year historical cohort, a 19.8% reduction was observed. For patients treated with primary PCI during lockdown, median symptom-to-balloon time increased by 44-minutes [217 (IQR 157-387) vs. 261 (160-659) minutes; p=0.03]; driven by an increase in median symptom-to-door time of 41-minutes [136 (IQR 80-267) vs. 177 (IQR 90-569) minutes; p<0.01]. Only patients transferred from non-PCI facilities demonstrated an increase in door-to-reperfusion time [116 (IQR 93-150) vs. 139 (IQR 100-199) minutes; p<0.01]. More patients had left ventricular dysfunction during the lockdown [35% vs. 44%; p=0.04], but there was no difference in mortality.

CONCLUSION

During the COVID-19 lockdown, fewer patients presented with STEMI. Time-to-reperfusion was significantly prolonged and appeared driven predominantly by patient-level and transfer delays. Public education and systems-level changes will be integral to STEMI care during the second wave of COVID-19.

Head-to-Head Comparison of Consensus-Recommended Platelet Function Tests to Assess P2Y12 Inhibition-Insights for Multi-Center Trials

The vasodilator-associated stimulated phosphoprotein (VASP) phosphorylation level is a highly specific method to assess P2Y12 receptor inhibition. Traditionally, VASP phosphorylation is analyzed by flow cytometry, which is laborious and restricted to specialized laboratories. Recently, a simple ELISA kit has been commercialized. The primary objective of this study was to compare the performance of VASP assessment by ELISA and flow cytometry in relation to functional platelet aggregation testing by Multiplate^® whole-blood aggregometry. Blood from 24 healthy volunteers was incubated with increasing concentration of a P2Y12 receptor inhibitor (AR-C 66096). Platelet function testing was carried out simultaneously by Multiplate^® aggregometry and by VASP assessment through ELISA and flow cytometry. As expected, increasing concentrations of the P2Y12 receptor inhibitor induced a proportional inhibition of platelet aggregation and P2Y12 receptor activation across the modalities. Platelet reactivity index values of both ELISA- and flow cytometry-based VASP assessment methods correlated strongly (r = 0.87, p < 0.0001) and showed minimal bias (1.05%). Correlation with Multiplate^® was slightly higher for the flow cytometry-based VASP assay (r = 0.79, p < 0.0001) than for the ELISA-based assay (r = 0.69, p < 0.0001). Intraclass correlation (ICC) was moderate for all the assays tested (ICC between 0.62 and 0.84). However, categorization into low, optimal, or high platelet reactivity based on these assays was strongly concordant (κ between 0.86 and 0.92). In conclusion, the consensus-recommended assays with their standardized cut-offs should not be used interchangeably in multi-center clinical studies but, rather, they should be standardized throughout sites.

Bivalirudin for Primary Percutaneous Coronary Interventions

Background—

Data from randomized trials has demonstrated the superiority of bivalirudin to glycoprotein IIb/IIIa inhibitors plus heparin in patients undergoing primary percutaneous coronary intervention. Real-world performance of bivalirudin in primary percutaneous coronary intervention and the benefit of bivalirudin over heparin remain unknown in an era of routine dual antiplatelet therapy.

Methods and Results—

From July 2004 to December 2010, 2317 consecutive patients were indexed in the University of Ottawa Heart Institute ST-segment–elevation myocardial infarction registry. During this period 748 patients received bivalirudin, 699 patients received glycoprotein IIb/IIIa inhibitors, and 676 patients received unfractionated heparin alone. The primary outcome was the rate of noncoronary artery bypass graft related thrombolysis in myocardial infarction major bleeding. Bivalirudin significantly reduced the primary outcome compared with heparin plus glycoprotein IIb/IIIa inhibitors (2.7% versus 7.3%, adjusted OR 2.96, 95% CI: 1.61–5.45, P <0.001) and the composite end point of death, stroke, reinfarction and major bleed (OR 1.66, 95% CI: 1.12–2.45, P =0.01). Compared with heparin alone, a reduction in major bleeds (OR 1.21, 95% CI: 0.60–2.44, P =0.59) or the composite end point (1.05, 95% CI: 0.68–1.63, P =0.83) with bivalirudin could not be demonstrated. Notably, major bleeding was associated with a 5-fold increase in the risk of mortality both in-hospital (3.5% versus 20.6%) and out to 180 days (5.6% versus 25.8%).

Conclusions—

Bivalirudin use compared with glycoprotein IIb/IIIa inhibitors plus heparin as an antithrombotic strategy in primary percutaneous coronary intervention results in less major bleeding in contemporary practice. A benefit of bivalirudin over heparin could not be established with this registry and requires additional investigations to either confirm or refute.

ST segment resolution in patients with tenecteplase-facilitated percutaneous coronary intervention versus tenecteplase alone: Insights from the Combined Angioplasty and Pharmacological Intervention versus Thrombolysis ALone in Acute Myocardial Infarction (CAPITAL AMI) trial

BACKGROUND

Compared with fibrinolysis alone, fibrinolysis followed by immediate percutaneous coronary intervention (PCI) reduced clinical events in the Combined Angioplasty and Pharmacological Intervention versus Thrombolysis ALone in Acute Myocardial Infarction (CAPITAL AMI) study. It is unclear whether the benefits go beyond achieving epicardial reperfusion.

OBJECTIVES

To determine the differences in ST segment resolution (STR) among patients treated with tenecteplase (TNK)-facilitated PCI compared with patients treated with TNK alone.

METHODS AND RESULTS

A formal ST segment analysis was conducted on the 170 patients with ST elevation myocardial infarction in the CAPITAL AMI trial: 86 patients treated with TNK-facilitated PCI were compared with 84 patients who were treated with TNK alone. Epicardial flow measured by percentage with Thrombolysis In Myocardial Infarction (TIMI) 3 flow improved from 52% (pre-PCI) to 89% (post-PCI) in those assigned to facilitated PCI. ST segment resolution was stratified by complete (70% or greater), partial (less than 70% to 30%) or no (less than 30% to 0%) resolution. The baseline mean ST segment elevation was 11.3+/-7.5 mm in the facilitated PCI patients and 11.8+/-7.1 mm in patients with TNK alone (P=0.66). Complete STR in the facilitated PCI patients versus the TNK-alone patients was present in 55.6% versus 54.6%, respectively (P=0.58) at 180 min and 62.0% versus 55.3% (P=0.64), respectively at day 1. The mean STR at 180 min and day 1 were similar in patients who experienced death, reinfarction, recurrent unstable ischemia or stroke at six months compared with patients who remained event free: 56.3% versus 64.6% at 180 min (P=0.40); and 67.7% versus 67.6% at day 1 (P=0.99), respectively.

CONCLUSIONS

TNK-facilitated PCI did not demonstrate differences in ST segment resolution compared with TNK alone, despite improvement in epicardial flow after PCI. Further studies are required to clarify these findings.

Effects of brefeldin-A on Golgi morphology in human cultured fibroblasts observed in three-dimensional stereo scanning electron microscopy

Brefeldin A (BFA) has been reported to cause disassembly of the Golgi. We have used three-dimensional (3-D) high-resolution scanning electron microscopy (HRSEM) to investigate these effects in human skin fibroblast cells. The spontaneous reassembly during prolonged exposure to BFA and some effects of forskolin were observed. A BFA concentration of 5 micrograms/ml caused Golgi complexes to become vesicular, resulting in a progressive decrease in the size of the Golgi. Morphologic changes were visible within 2 min of BFA incubation, and by 30 min no identifiable Golgi could be found. Spontaneous reassembly of the Golgi apparatus upon the removal of the BFA or with continued long-term exposure with BFA could not be confirmed. Preliminary experiments with forskolin were not effective in reversing or inhibiting the effects of BFA in human fibroblast cells grown in culture. This inability for spontaneous reassembly and nonreversal by forskolin may reflect a differential effect of BFA in various cell types. HRSEM has proven to be useful for observing 3-D morphologic effects of BFA in Golgi.

Advantages of digitonin extraction to reveal the intracellular structure of rat glomerular podocytes for high-resolution scanning electron microscopy

Kidneys of anesthetized rats were perfused with digitonin to extract cytosolic proteins of glomerular podocytes so that the remaining intracellular structures could be examined by three-dimensional stereo high-resolution scanning electron microscopy (HRSEM). Cytoskeleton, consisting of microtubules and intermediate filaments, was preserved with each applied concentration of digitonin. High concentrations of digitonin (1.0 mg/ml) produced a corrugated appearance in plasma membranes likely due to the formation of digitonin-cholesterol complexes. At 1.0 mg/ml digitonin, the Golgi complex became vesicularized, and mitochondria were well extracted and their ultrastructure preserved. Lower concentrations of digitonin (0.1 and 0.2 mg/ml) were less disruptive to both the plasma membrane and the Golgi complex. Mitochondria, rough endoplasmic reticulum, coated vesicles, nuclear membrane, and chromatin were well preserved. Extraction with digitonin, at the optimal concentration and perfusion time, simultaneously maintains both the cytoskeleton and membranous organelles inside the cell and provides a method to elucidate the interactions between these two components. Furthermore, digitonin extraction should preserve antigenic sites, thereby allowing the localization of intracellular proteins by backscattered electron imaging of immunogold labels in the scanning electron microscope.