Antiplatelet therapy and coronary artery bypass grafting: Protocol for a systematic review and network meta-analysis

Impact of provincial and national implementation strategies on P2Y12 inhibitor utilization for acute coronary syndrome in the elderly: an interrupted time series analysis from 2008 to 2018

Background

Guidelines recommend both acetylsalicylic acid and ticagrelor following acute coronary syndrome (ACS), but appropriate prescription practices lag. We analyzed the impact of government medication approval, national guideline updates, and publicly funded drug coverage plans on P2Y12 inhibitor utilization.

Methods

Accessing provincial databases, we obtained data for elderly ACS patients in Ontario, Canada, between 2008 and 2018. Using interrupted-time series with descriptive statistics and segmented regression analysis, we evaluated types of P2Y12 inhibitors prescribed at discharge and changes to their utilization in patients managed with percutaneous intervention (PCI), coronary artery bypass grafting (CABG) or medically, following national antiplatelet therapy guidelines (by the Canadian Cardiovascular Society), ticagrelor’s national approval by Health Canada, and ticagrelor’s coverage by a publicly funded medication plan.

Results

We included 114,142 patients (49.4%-PCI; mean age 75.71±6.94 and 62.3% male and 7.7%-CABG; mean age 74.11±5.63 and 73.5% male).

Among PCI patients, clopidogrel utilization declined monthly after 2010 national guidelines were published (p<0.0001) and within the first month after ticagrelor’s national approval by Health Canada (p=0.03). Among PCI patients, ticagrelor utilization increased within the first month (p<0.0001) and continued increasing monthly (p<0.0001) after its coverage by a publicly funded medication plan. Among PCI patients, clopidogrel utilization declined within the first month (p=0.003) and ticagrelor utilization increased monthly (p=0.05) after 2012 CCS guidelines.

Among CABG patients, ticagrelor’s coverage was associated with a monthly increase in its utilization (p<0.0001).

Conclusion

National guideline updates and drug coverage by a publicly funded medication plan significantly improved P2Y12 inhibitor utilization. Barriers to appropriate antiplatelet therapy in the surgical population must be explored.

Antiplatelet therapy and coronary artery bypass grafting: a systematic review and network meta-analysis

OBJECTIVES

Acetylsalicylic acid (ASA) monotherapy is the standard of care after coronary artery bypass grafting (CABG), but the benefits of more intense antiplatelet therapy, specifically dual antiplatelet therapy (DAPT), require further exploration in CABG patients. We performed a network meta-analysis to compare the effects of various antiplatelet regimens on saphenous vein graft patency, mortality, major adverse cardiovascular events and bleeding among CABG patients.

METHODS

We searched Cochrane Central Register of Controlled Trials, Medical Literature Analysis and Retrieval Systems Online, Excerpta Medica Database, Cumulative Index to Nursing and Allied Health Literature, American College of Physicians Journal Club and conference proceedings for randomized controlled trials. Screening, data extraction, risk of bias assessment and Grading of Recommendations Assessment, Development and Evaluation were performed in duplicate. We conducted a random effect Bayesian network meta-analysis including both direct and indirect comparisons.

RESULTS

We included 43 randomized controlled trials studying 15 511 patients. DAPT with low-dose ASA and ticagrelor [odds ratio (OR) 2.53, 95% credible interval (CrI) 1.35–4.72; I2 = 55; low certainty] or clopidogrel (OR 1.56, 95% CrI 1.02–2.39; I2 = 55; very low certainty) improved saphenous vein graft patency when compared to low-dose ASA monotherapy. DAPT with low-dose ASA and ticagrelor was associated with lower mortality (OR 0.52, 95% CrI 0.30–0.87; I2 = 14; high certainty) and lower major adverse cardiovascular events (OR 0.63, 95% CrI 0.44–0.91; I2 = 0; high certainty) when compared to low-dose ASA monotherapy. Based on moderate certainty evidence, DAPT was associated with an increase in major bleeding.

CONCLUSIONS

Our results suggest that DAPT improves saphenous vein graft patency, mortality and major adverse cardiovascular event. As such, surgeons and physicians should consider re-initiating DAPT for acute coronary syndrome patients after their CABG, at the expense of an increased risk for major bleeding.

Clinical trial registration

International Prospective Register of Systematic Reviews ID Number CRD42019127695