The trajectory of statin compliance after coronary artery bypass grafting surgery
Authors: Bampali T , Efstathopoulos A , Siminelakis S 
Published: May 2023

Abstract

Funding Acknowledgements
Type of funding sources: None.

Background
The current guidelines about dyslipidemia classify coronary artery bypass grafting surgery (CABG) patients, as a very high-risk population. This is translated to a LDL-target ≤ 55mg/dL, based on observational studies that demonstrate better vein graft patency and deceleration of the native vessels’ atherosclerosis. Despite the well-defined benefit, the compliance of statin therapy at the secondary prevention is ailing.

Purpose
To capture and evaluate the trajectory of statin compliance during 4 years follow-up in patients after CABG, in a middle-income country.

Methods
This is a single-center, cohort, observational study, conducted in 365 consecutive post-CABG patients, from 2018-2021. We used data from the electronical files of the patients and the national electronical prescription platform, after consent. The follow-up period was divided: t1 = 6 months, t2 = 1 year, t3= 2 years, t4 = 3 years, and t5= 4 years. We defined as potent statin therapy the administration of ≥ 40mg of atorvastatin, ≥ 20mg of rosuvastatin or the concomitant use of ezetimibe.

Results
We included 365 patients, 52 females (14.4%). The median age was 69 years (ΙQR: 47-84). The indication for CABG was 65.7% an acute coronary syndrome and 34.3% stable coronary disease. At baseline, the mean LDL value was 108mg/dL, whereas one month post procedure was 71mg/dL, indicating reduction: Δ=34%. Alas, the achieved post-CABG LDL-level still is beyond the target of ≤ 55mg/dL. At t0 (discharge) the percentage of prescribed statins was 81%, but only in 68% of them, the statin was high potent. At t1 the rate of the compliance raised up to 92.5% and the potency rate to 74.6%. At t2 the compliance and the potency remained high, 94.3% and 74.8% respectively. At t3 the compliance is rather stable (92.3%) but the rate of potency declines (64%) and decline further at t4 (89% and 58% respectively). Finally, at t5 both indexes depleted (81% and 57.1%, respectively). The rate of escalation to a potent statin was: t1= 36.3%, t2= 13.9%, t3 = 12.4%, t4 = 3.8%, t5=2.1%. The de-escalation rate was: t1= 13.9%, t2= 2.4%, t3 = 7.3%, t4 = 0.8%, t5=0.1%. The prescribed statin remained the same at t1= 50.8%, t2= 83.6%, t3 = 76.6%, t4 = 79% and t5=75%. The rate of permanent discontinuation was null during the first year, 4.1% at 2 years, 18.2% at 3 years and 19.5% at 4 years.

Conclusions
The LDL level one-month post-CABG, remains out of target and a further 22% reduction is needed. We highlight the significant rate of prescribed statin at discharge and substantial compliance which is rather sustained during the follow-up period. Nota bene the rate of potency lessens over time, whereas the rate of permanent discontinuation raises, implying that as the patient enters a "stabilized period" at 2 years post-surgery, the eagerness to maintain high-potent statin therapy, declines. This real-world practice subtracts the pleiotropic benefits of potent statins, not only over the ongoing atherosclerosis.