Variables associated with bleeding and thrombotic outcomes among patients admitted to the hospital with COVID-19 and elevated D-dimer: insights from the ACTION randomised clinical trial

Background

In the ACTION trial, therapeutic anticoagulation did not show benefit on mortality, days of hospitalization and oxygens therapy at 30 days among patients with COVID19. However, this strategy was associated with higher rate of bleeding and a potential reduction in the rate of clinical thrombotic events. The current analysis evaluated which variables were independently associated with both outcomes in order to help the identification of the risk for thrombotic and hemorrhagic events among patients with COVID19.

Methods

A total of 615 patients hospitalized with COVID-19 and elevated D-dimer levels were randomly assigned to prophylactic anticoagulation (mainly in-hospital heparin) or a therapeutic strategy that used in-hospital rivaroxaban 20 mg daily for stable patients, or enoxaparin 1 mg/kg twice daily for unstable patients, followed by rivaroxaban through 30 days. One patient withdrew consent and was not included in the analysis. The current analysis tested baseline clinical characteristics and laboratorial exams one by one with independent logistic regressions for the composite of bleeding (major bleeding and clinically relevant nonmajor bleeding) and thrombotic events (venous thromboembolism, myocardial infarction, stroke, systemic embolism, and major adverse limb events). Significant variables (p<0.05) were selected to adjust several multiple logistic models. Final models were chosen based on Akaike information criterion and therapeutic anticoagulation was included in the final model based on the primary results of the trial.

Results

The model for bleeding events showed an accuracy of area under the curve (AUC) of 0.635 (table 1) while the model for thrombotic events had an AUC of 0.725 (table 2). Level of respiratory support (especially invasive ventilation) was associated with both outcomes in the multivariable analysis (tables 1 and 2). Beyond respiratory support, level of creatinine and history of coronary disease were also independently associated to the risk of thrombotic events. When the utilization of therapeutic anticoagulation (mainly with rivaroxaban) was included in the multivariable analysis, this variable was strongly associated with higher risk of bleeding (model AUC of 0.718) but was not associated with lower rate of thrombotic events (Tables 1 and 2).

Conclusion

Since the variables associated with higher risk of thrombotic events are similar to the variables associated to bleeding complications, the selection of patients with better balance of risk vs. benefit to use therapeutic anticoagulation in COVID-19 still a challenging decision. Coronary disease and creatine may help to identify patients at higher risk of thrombotic complications while the use of therapeutic dose of direct oral anticoagulant increased the risk of bleeding in almost 4 times among patients hospitalized due to COVID19.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Investigator initiated research with financial support of Bayer

P331Effect of exercise stress test on platelet function in patients with recent acute myocardial infarction

Background

Exercise-based cardiac rehabilitation for coronary artery disease (CAD) is associated with lower cardiovascular mortality. On the other hand, acute strenuous exercise has been linked to cardiovascular complications such as acute myocardial infarction (AMI) and sudden cardiac death. One of the pathophysiological mechanisms involved in these outcomes might be an increase in platelet aggregability after exercise. Although previous studies showed higher platelet aggregability after exercise among stable CAD patients on aspirin treatment, there is no data regarding the effect of exercise on platelet activity in post-AMI patients on dual anti-platelet therapy (DAPT).

Purpose

To evaluate the effect of high-intensity exercise on platelet aggregability in sedentary post-AMI patients on DAPT.

Methods

Platelet function was analyzed immediately before and after maximal cardiopulmonary exercise test (CPET) on cycle ergometer utilizing a personalized ramp protocol and aiming to achieving peak exercise in around 10 min. The CPET was done within 31±4 days after uncomplicated AMI. Platelet aggregability was assessed by Multiplate®ADPtest (MP-ADP) and Multiplate® ASPItest (MP-ASPI) measured as area under the curve (AUC). Reticulated platelets were measured concomitantly to MP-ADP e MP-ASPI using a fully automated flow cytometer (Sysmex XN-2000®) to determine absolute immature platelet count (IPC) per 103/microliter. Continuous variables were expressed as means ±standard deviation or as median and 25th–75th percentiles if not Gaussian distributed. Comparisons between the pre- and post-CPET assessments were performed using Wilcoxon signed rank test.

Results

We analyzed 81 sedentary patients (mean age 58.3±10.1 years-old, 76.5% men) after AMI (50.6% with ST-elevation myocardial infarction, mean left ventricular ejection fraction after index event 55±11.7%, 98.8% on statin and 85.5% on beta-blocker treatment). Platelet aggregability, either by MP-ADP or MP-ASPI, and IPC were significantly increased after CPET (table).

Platelet function after CPET Before CPET After CPET p-value Multiplate® ADPtest (AUC) – median (25th–75th percentiles) 32.0 (22.0–48.5) 37.0 (26.0–55.2) 0.003 Multiplate® ASPItest (AUC) – median (25th–75th percentiles) 17.0 (12.7–22.0) 22.0 (16.7–28.0) <0.001 Immature platelet count (103/microliter) – median (25th–75th percentiles) 9.5 (6.8–13.8) 9.6 (6.6–16.5) 0.006 CPET: cardiopulmonary exercise test; AUC: area under the curve.

Conclusion

On this post-AMI population, platelet was hyperactivated after exercise stress test despite the use of DAPT. These findings suggest that, even when properly treated, post-AMI patients might be at higher risk of ischemic complications after high-intensity exercises, reinforcing the importance of tailoring exercise prescription in this population.

Acknowledgement/Funding

Sao Paulo Research Foundation, FAPESP

P1839Platelet aggregability evaluation in patients with acute coronary syndromes scheduled for coronary artery bypass graft. The PLAT-CABG study

Background

Dual antiplatelet therapy is recommended for patients (pts) with acute coronary syndromes (ACS). However, 10–15% of pts have indication of coronary artery bypass graft (CABG) for the index event and current guidelines recommend stopping clopidogrel at least 5 days prior to CABG. This waiting time could increase hospital length of stay, thus having negative impacts on costs and clinical complications.

Purpose

To evaluate if release to CABG based on platelet aggregability by Multiplate AnalyzerTM would be non-inferior in comparison with common practice (5 days) in terms of 24-hours post-CABG bleeding.

Methods

The PLAT-CABG (NCT 02516267) is a randomized, open label, non-inferiority trial (boundary 25%) testing a strategy of platelet aggregability-guided release to CABG versus standard-of-care on the primary endpoint of chest tube drainage in the first 24 hours post CABG. A total of 190 pts admitted with ACS, treated with aspirin + clopidogrel and with indication for CABG, were assigned to clopidogrel discontinued 5 days prior to CABG (control group) vs. daily measurements of platelet aggregability to ADP using Multiplate AnalyzerTM (intervention group) with CABG occurring after recovering from platelet inhibition (pre-defined as a threshold of 46 AU).

Results

The main results are depicted in the table

Main results of PLAT-CABG study Variables Control Group (n=95) Intervention Group (n=95) P-value for superiority P-value for non-inferiority Chest tube drainage (mL), Median (25th–75th) 350 (250–500) 350 (250–500) 0.680 0.001 Time symptom to CABG (hours), Median (25th–75th) 191 (150–281) 166 (119–225) <0.001 NA Time surgery indication to CABG (hours), Median (25th–75th) 136 (112–161) 112 (66–142) <0.001 NA CABG = coronary artery bypass graft.

Conclusion

Platelet-aggregability guided release to CABG is non-inferior to standard of care in ACS patients awaiting CABG in terms of peri-operative bleeding and significantly shortens the time to CABG.

Acknowledgement/Funding

Roche Diagnostica Brazil