Ticagrelor and aspirin is a common dual antiplatelet therapy regimen for patients who undergo percutaneous coronary intervention. Despite its ability to significantly reduce cardiovascular complications, ticagrelor response may be altered by other medications causing subtherapeutic effects. Traditionally, ticagrelor is thought to have fewer drug–drug interactions compared to other thienopyridine antiplatelet medications such as clopidogrel. Primidone, metabolized into phenobarbital, is a strong CYP-3A inducer that can reduce serum concentrations of ticagrelor resulting in ineffective antiplatelet therapy. We present a 67-year-old male who suffered in-stent thrombosis after percutaneous intervention possibly due to the interaction between primidone and ticagrelor.
Background
There have been limited reports with inconsistent results on the impact of long-term use of oxygen therapry (LTOT) in patients treated with transcatheter aortic valve replacement (TAVR).
Methods
We compared in-hospital and intermediate TAVR outcomes in 150 patients requiring LTOT (home O
2
cohort) with 2,313 non-home O
2
patients.
Results
Home O
2
patients were younger, and had more comorbidities including chronic obstructive pulmonary disease (COPD), diabetes, carotid artery disease, lower forced expiratory volume (FEV
1
) (50.3±21.1% vs. 75.0±24.7%, P < 0.001), and lower diffusion capacity (DLCO, 48.6±19.2% vs. 74.6±22.4%, P < 0.001). These differences represented higher baseline Society of Thoracic Surgeons (STS) risk score (15.5±10.2% vs. 9.3±7.0%, P < 0.001) and lower pre-procedure Kansas City Cardiomyopathy Questionnaire (KCCQ-12) scores (32.5 ± 22.2 vs. 49.1 ± 25.4, P < 0.001). The home O
2
cohort required higher use of alternative TAVR vascular access (24.0% vs. 12.8%, P = 0.002) and general anesthesia (51.3% vs. 36.0%, P < 0.001). Compared to non-home O
2
patients, home O
2
patients showed increased in-hospital mortality (5.3% vs. 1.6%, P = 0.001), procedural cardiac arrest (4.7% vs. 1.0%, P < 0.001), and postoperative atrial fibrillation (4.0% vs. 1.5%, P = 0.013). At 1-year follow-up, the home O
2
cohort had a higher all-cause mortality (17.3% vs. 7.5%, P < 0.001) and lower KCCQ-12 scores (69.5 ± 23.8 vs. 82.1 ± 19.4, P < 0.001). Kaplan-Meir analysis revealed a lower survival rate in the home O
2
cohort with an overall mean (95% confidence interval (CI)) survival time of 6.2 (5.9 - 6.5) years (P < 0.001).
Conclusion
Home O
2
patients represent a high-risk TAVR cohort with increased in-hospital morbidity and mortality, less improvement in 1-year KCCQ-12, and increased mortality at intermediate follow-up.
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