Impact of lipid-lowering medications and low-density lipoprotein levels on 1-year clinical outcomes after coronary artery bypass grafting

The prognostic role of the low and very low baseline LDL-C level in outcomes of patients with cardiac revascularization; comparative registry-based cohort design

BACKGROUND

Although low-density lipoprotein-cholesterol (LDL-C) level is considered one of the main prognostic factors in patients with coronary artery bypass grafting (CABG), the question about "the lower the better" is still unanswered. We aimed to evaluate and compare the outcomes of patients with CABG and low or very low baseline LDL-C, regardless of statin usage.

METHODS

In this registry-based cohort study, 10,218 patients with low/very low (70-100 and ≤ 70 mg/dL) baseline LDL-C who underwent isolated and the first-time CABG without known previous history of cardio-cerebrovascular events, were included and compared. The median follow-up was 73.33 (72.15-74.51) months. Primary outcomes were all-cause mortality and major adverse cardio-cerebrovascular events (MACCE) (consisted of all-cause mortality, acute coronary syndrome, stroke or transient ischemic attack, and the need for repeat revascularization [percutaneous coronary intervention or redo-CABG]). Cox regression analyses before and after the propensity score matching (PSM) model were applied to evaluate and compare outcomes.

RESULTS

The mean age of the study population was 66.17 ± 9.98 years old and 2506 (24.5%) were women. Diabetes mellitus and a history of cigarette smoking were significantly higher in the very low LDL group (P-value ≤ 0.001). In Cox regression analyses before applying PSM model, both all-cause mortality (14.2% vs. 11.9%, P-value = 0.004 and MACCE (26.0% vs. 23.6%, P-value = 0.006) were significantly higher in the very low LDL group compared to low LDL. However, these results were no longer significant after applying the PSM model (all-cause mortality HR: 1.115 [95% CI: 0.986-1.262], P = 0.083 and MACCE HR: 1.077 [95%CI: 0.984-1.177], P = 0.095). The sensitivity analysis to remove the statin effect demonstrated that very low LDL-C level was correlated to higher risk of all-cause mortality in both unmatched and PSM analyses.

CONCLUSION

Very low serum LDL-C levels (≤ 70 mg/dl) could increase long-term all-cause mortality and cardiovascular events in patients who have undergone isolated CABG.

Impact of Conventional Cardiovascular Risk Factors on Left Internal Mammary Artery Graft Disease

Background:

The development of atherosclerosis was considered as the common cause of the stenosis of coronary artery grafts. Left internal mammary artery (LIMA) was the best artery graft for further effectiveness of coronary artery bypass grafting (CABG). We sought to assess the impact of known conventional cardiovascular risk factors (RFs) on LIMA graft stenosis.

Methods:

A retrospective study including 618 participants, who had recurrence of chest pain after CABG, aged ≥18 years, hospitalized for coronary angiography in Beijing Anzhen hospital between 2010 and 2017 was performed. All the participants were confirmed to have LIMA graft. Multivariate analysis was conducted to determine the relationship between conventional RFs and LIMA graft stenosis.

Results:

Of the study, 220 (35.6%) participants continued to smoke, 504 (81.6%) were overweight or obese, and 411 (66.5%) and 242 (39.2%) reported concomitant hypertension and diabetes, respectively. LIMA graft stenosis occurred in 161 participants (26.1%). Postoperative smoking, a CABG duration of ≥10 years and hyperglycemia without diabetes had an increased risk of LIMA graft stenosis, the odds ratio (OR) was 1.86 [95% confidence interval (CI): 1.26–2.78], 2.24 (95%CI:1.33–3.478), and 2.44(95% CI:1.39–4.32), respectively. Statin use (OR, 0.28; 95% CI: 0.25–0.5) and low-density lipoprotein cholesterol (LDL-C) < 1.8 mmol/L (OR, 0.27; 95% CI: 0.14–0.53) had a significantly decreased risk of LIMA graft stenosis. While, only 15.4% (95/618) achieved the target LDL-C level.

Conclusions:

Postoperative smoking and hyperglycemia without diabetes had an increased risk of LIMA graft stenosis. Statin use and LDL-C <1.8 mmol/L decreased the risk.

John TJ, Alfardan S, Traina MI, Almahmeed W. Lipid Control Post Coronary Artery Bypass Graft: One Year Follow-Up of a Middle-Eastern Cohort

Background

Data on patient characteristics and provider practices in the management of lipids per the new guidelines in specific secondary prevention patients in the Middle East is limited.

Objective

To explore patient characteristics and lipid management practices according to the new cholesterol guidelines in secondary prevention patients, up to one year following discharge for coronary artery bypass graft surgery (CABG).

Methods

A retrospective chart review of patients discharged post CABG between February 2017 and February 2018 at a quaternary care centre in the Middle East. Patients were characterized by baseline demographics, comorbidities, and use of lipid lowering medications.

Results

189 patients were included in the analysis. Most were diabetic (70.9%) and classified as very high risk per the ACC/AHA guidelines (84.1%) and as extremely high risk per the AACE guidelines (85.2%). Most patients (93.1%) were discharged on high intensity statin. About one third (28.6%) were never seen or only followed once within the first 2 weeks post discharge. Of those who continued to follow up beyond 3 months and within 1 year of discharge (44.4%), about half (51.2%) had follow-up lipid panels performed. Patients who followed up and were seen by a cardiologist were five times more likely to have lipid panels ordered than those seen solely by a CT surgeon. Of those with follow-up lipid panels beyond 3 months: 59.3% achieved LDL goal of <70 mg/dL and 29% achieved LDL <55 mg/dL based on their respective goals.

Conclusions

Most patients undergoing CABG in a quaternary care centre in the Middle East are high risk ASCVD. Nonetheless, lipid goals are not commonly achieved nor routinely monitored. Providers will need to transition from the previous risk stratification and statin-only focused approach to adopt the most recent guidelines.

Comparison of Secondary Prevention Status between Percutaneous Coronary Intervention and Coronary Artery Bypass Patients

Background

Data are scarce regarding disparities in cardiovascular risk factor management between patients treated with percutaneous coronary intervention (PCI) and those treated with coronary artery bypass grafting (CABG).

Objective

Whether the goal achievement rates of cardiovascular risk factors were different between PCI and CABG patients.

Methods

We retrospectively reviewed the data retrieved from a clinical record database of patients admitted to Beijing Anzhen Hospital between January 1, 2014, and December 31, 2014, who underwent PCI or CABG.

Results

Compared with the CABG group, low-density lipoprotein cholesterol (LDL-C) < 1.8 mmol/L (28.6% vs. 24.7%; p < 0.01), LDL-C < 2.07 mmol/L (43.5% vs. 39.4%; p < 0.01) and blood pressure (BP) < 140/90 mm Hg (85.6% vs. 77.7%; p < 0.01) goal achievement rates were significantly higher in the PCI group. Compared with patients ≥ 60 years old: patients < 60 years old had better BP < 140/90 mm Hg goal achievement rates (87.7% vs. 84.4%; p < 0.01) in the PCI group, and better fasting blood-glucose (FBG) < 7 mmol/L (79.4% vs.72.0%; p < 0.01) and HbA1c < 7% (79.4% vs. 70.1%; p < 0.01) goal achievement rates in the CABG group. Compared with females: males had better LDL-C < 2.07 mmol/L (24.7% vs. 28.5%; p < 0.01), FBG < 7 mmol/L (71.8% vs.75.2%; p < 0.01) and HbA1c < 7% (70.4% vs. 74.1%; p < 0.01) goal achievement rates in the PCI group.

Conclusion

Patients in the PCI group were generally more likely than those in the CABG group to achieve LDL-C < 1.8 mmol/L and BP goals. The control of cardiovascular risk factors differed between patients ≥ 60 years old and < 60 years old. Female patients were less likely to achieve LDL-C, FBG and HbA1c goals.