Low-Density Lipoprotein Cholesterol Level and Statin Therapy in Patients With Acute Myocardial Infarction (Cholesterol Paradox)

Admission LDL-cholesterol, statin pretreatment and early outcomes in acute ischemic stroke

BACKGROUND

Lipid paradox of low LDL-C may cause physicians to be reluctant to use statins in acute ischemic stroke (AIS) patients with low LDL-C levels at admission.

OBJECTIVE

This study investigated the association between LDL-C levels and early vascular outcomes and assessed the potential interaction effect between LDL-C and statin pretreatment on early outcomes.

PATIENTS AND METHODS

This was a study of a prospective, multicenter, registry of AIS patients with admission LDL-C. The subjects were divided into 3 groups according to LDL-C levels: low LDL-C (≤100 mg/dL); intermediate LDL-C (>100, <130 mg/dL); and high LDL-C (≥130 mg/dL). The primary early vascular outcome was a composite of stroke (ischemic or hemorrhagic), myocardial infarction and all-cause mortality within 3 months. The associations of LDL-C levels as a continuous variable and the risks of primary outcome using Cox proportional hazards models with restricted cubic splines were explored.

RESULTS

A total of 32,505 patients (age, 69 ± 12; male, 58.6%) were analyzed. The 3 groups showed significant differences in the 3-month primary outcome, with highest events in the low LDL-C group; after adjustment, no significant associations with the 3-month primary outcome remained. U-shaped nonlinear relationships of LDL-C levels with the 3-month primary outcome were observed (Pnon-linearity<0.001), with substantial relationships in the no pretreatment subgroup.

CONCLUSIONS

The relationships between admission LDL-C levels and early outcomes are complex but appear to be paradoxical in patients with low LDL-C and no statin pretreatment. The results suggest that statin pretreatment might offset the paradoxical response of low LDL-C on early vascular outcomes. Further study would be warranted.

Are there sex differences in the effect of type 2 diabetes in the incidence and outcomes of myocardial infarction? A matched-pair analysis using hospital discharge data

BACKGROUND

To analyze incidence, use of therapeutic procedures, and in-hospital outcomes in patients with ST elevation myocardial infarction (STEMI) and non-ST elevation myocardial infarction (NSTEMI) according to the presence of type 2 diabetes (T2DM) in Spain (2016-2018) and to investigate sex differences.

METHODS

Using the Spanish National Hospital Discharge Database, we estimated the incidence of myocardial infarctions (MI) in men and women with and without T2DM aged ≥ 40 years. We analyzed comorbidity, procedures, and outcomes. We matched each man and woman with T2DM with a non-T2DM man and woman of identical age, MI code, and year of hospitalization. Propensity score matching was used to compare men and women with T2DM.

RESULTS

MI was coded in 109,759 men and 44,589 women (30.47% with T2DM). The adjusted incidence of STEMI (IRR 2.32; 95% CI 2.28-2.36) and NSTEMI (IRR 2.91; 95% CI 2.88-2.94) was higher in T2DM than non-T2DM patients, with higher IRRs for NSTEMI in both sexes. The incidence of STEMI and NSTEMI was higher in men with T2DM than in women with T2DM. After matching, percutaneous coronary intervention (PCI) was less frequent among T2DM men than non-T2DM men who had STEMI and NSTEMI. Women with T2DM and STEMI less frequently had a code for PCI that matched that of non-T2DM women. In-hospital mortality (IHM) was higher among T2DM women with STEMI and NSTEMI than in matched non-T2DM women. In men, IHM was higher only for NSTEMI. Propensity score matching showed higher use of PCI and coronary artery bypass graft and lower IHM among men with T2DM than women with T2DM for both STEMI and NSTEMI.

CONCLUSIONS

T2DM is associated with a higher incidence of STEMI and NSTEMI in both sexes. Men with T2DM had higher incidence rates of STEMI and NSTEMI than women with T2DM. Having T2DM increased the risk of IHM after STEMI and NSTEMI among women and among men only for NSTEMI. PCI appears to be less frequently used in T2DM patients After STEMI and NSTEMI, women with T2DM less frequently undergo revascularization procedures and have a higher mortality risk than T2DM men.

Admission Low-Density Lipoprotein Cholesterol Stratified by Circulating CD14++CD16+ Monocytes and Risk for Recurrent Cardiovascular Events Following ST Elevation Myocardial Infarction: Lipid Paradox Revised

Lower level of low-density lipoprotein cholesterol (LDL-C) is paradoxically associated with increased mortality in ST elevation myocardial infarction (STEMI) patients. The underlying mechanism remains unclear. In a cohort of 220 de novo STEMI patients receiving timely primary percutaneous coronary intervention, admission LDL-C was negatively associated with circulating CD14++CD16+ monocyte counts. Moreover, admission LDL-C < 85 mg/dL was associated with increased risk for major adverse cardiovascular events (MACE) during a median follow-up of 2.7 years. After categorizing the patients according to the cutoff values of 85 mg/dL for LDL-C and the median for CD14++CD16+ monocytes, low LDL-C-associated MACE risk was only observed in those with high CD14++CD16+ monocyte counts (low LDL-C/high CD14++CD16+ monocytes vs. low LDL-C/low CD14++CD16+ monocytes: hazard ratio 5.38, 95% confidence interval 1.52 to 19.06, P = 0.009). This work provided the proof-of-principle evidence indicating a role of CD14++CD16+ monocytes in risk stratification of STEMI patients presenting with low LDL-C level. Graphical abstract.

Baseline plasma lipid levels in patients with acute coronary syndrome: Association with 20-year mortality. The ABC-5a* Study on Heart Disease

BACKGROUND

The relationship between baseline plasma lipid levels during acute coronary syndrome and the outcome has clinical relevance.

METHODS

To evaluate their long-term prognostic value, we examined 589 patients admitted with acute coronary syndrome at three hospitals. Baseline plasma lipids were assessed on days 1 and 7. Patients were followed for 20 years or until death.

RESULTS

Virtually, all patients completed follow-up; 437 (74%) had died: 24% from coronary artery disease/heart failure (CAD/HF), 21% sudden cardiac death (SCD), 16% from other cardiovascular causes and 39% had non-cardiac death. The incidence rate (IR) of all-cause mortality was not different among patients with baseline plasma lipids less or greater than the median value. The IR of CAD/HF mortality was not significantly higher among patients with greater than median low-density lipoprotein (LDL) cholesterol and triglyceride (TG) levels. The IR of non-cardiac death tended to be lower among patients with greater than median total cholesterol (TC) and LDL levels. Using three levels of adjusted Cox survival models, baseline plasma lipids had no consistent independent or inverse association with all-cause mortality, even after excluding patients who received statins. Competitive risk survival models for each cause of death revealed that the only hazard of non-cardiac death was consistently higher among patients with less than or equal to median TC and LDL levels.

CONCLUSION

In the present prospective long-term study, after acute coronary syndrome, baseline plasma lipid levels seem not to be associated with long-term global mortality. Only an independent inverse association between TC and LDL and non-cardiac death has been observed.

The Lipid Paradox is present in ST-elevation but not in non-ST-elevation myocardial infarction patients: Insights from the Singapore Myocardial Infarction Registry

Lowering low-density lipoprotein (LDL-C) and triglyceride (TG) levels form the cornerstone approach of cardiovascular risk reduction, and a higher high-density lipoprotein (HDL-C) is thought to be protective. However, in acute myocardial infarction (AMI) patients, higher admission LDL-C and TG levels have been shown to be associated with better clinical outcomes - termed the 'lipid paradox'. We studied the relationship between lipid profile obtained within 72 hours of presentation, and all-cause mortality (during hospitalization, at 30-days and 12-months), and rehospitalization for heart failure and non-fatal AMI at 12-months in ST-segment elevation myocardial infarction (STEMI) and non-ST-segment elevation myocardial infarction (NSTEMI) patients treated by percutaneous coronary intervention (PCI). We included 11543 STEMI and 8470 NSTEMI patients who underwent PCI in the Singapore Myocardial Infarction Registry between 2008-2015. NSTEMI patients were older (60.3 years vs 57.7 years, p < 0.001) and more likely to be female (22.4% vs 15.0%, p < 0.001). In NSTEMI, a lower LDL-C was paradoxically associated with worse outcomes for death during hospitalization, within 30-days and within 12-months (all p < 0.001), but adjustment eliminated this paradox. In contrast, the paradox for LDL-C persisted for all primary outcomes after adjustment in STEMI. For NSTEMI patients, a lower HDL-C was associated with a higher risk of death during hospitalization but in STEMI patients a lower HDL-C was paradoxically associated with a lower risk of death during hospitalization. For this endpoint, the interaction term for HDL-C and type of MI was significant even after adjustment. An elevated TG level was not protective after adjustment. These observations may be due to differing characteristics and underlying pathophysiological mechanisms in NSTEMI and STEMI.

Benefits of Statin Therapy in Patients With Acute Myocardial Infarction With Serum Low-Density Lipoprotein Cholesterol ≤ 50 mg/dl

Previous trials have found that statin therapy reduces low-density lipoprotein cholesterol (LDL-C) level and the risk of cardiovascular events. However, the benefit of statin therapy in patients with baseline LDL-C levels ≤ 50 mg/dl is less clear. Therefore, the aim of this study was to assess whether patients with acute myocardial infarction (AMI) who have baseline LDL-C levels ≤ 50 mg/dl would benefit from statin therapy in real-world clinical practice. We analyzed the clinical data of 1,048 patients (67.3 ± 12.6 years, 69.6% men) with AMI, who had baseline LDL-C levels ≤ 50 mg/dl from the Korean Acute Myocardial Infarction Registry data between November 2005 and May 2014. They were divided into 2 groups based on whether they were prescribed statins or not at discharge (statin and nonstatin group, n = 738 and 310, respectively). The primary end point was the major adverse cardiac event (MACE), defined as the composite of all-cause mortality, recurrent myocardial infarction, and repeated percutaneous coronary intervention or coronary artery bypass grafting. MACE occurred in 9.2% of the statin group versus 19.6% in the nonstatin group during the 12-month follow-up. Statin therapy significantly reduced the risk of MACE (hazard ratio [HR] 0.60, 95% CI 0.39 to 0.94, p = 0.025) and coronary artery bypass grafting (HR 0.27, 95% CI 0.08 to 0.96, p = 0.043). There was a trend of reduced cardiac death in the statin group compared with the nonstatin group (HR 0.52, 95% CI 0.26 to 1.02, p = 0.059). Statin therapy for patients with AMI with LDL-C levels ≤ 50 mg/dl was associated with improved outcomes. Therefore, statin therapy is feasible and effective, even in AMI patients with extremely low levels of LDL-C.

Low-density lipoprotein cholesterol and survival in pulmonary arterial hypertension

Low-density lipoprotein cholesterol(LDL-C) is a well established metabolic marker of cardiovascular risk, however, its role in pulmonary arterial hypertension (PAH) has not been determined. Therefore we assessed whether LDL-C levels are altered in PAH patients, if they are associated with survival in this group and whether pulmonary hypertension (PH) reversal can influence LDL-C levels. Consecutive 46 PAH males and 94 females were age matched with a representative sample of 1168 males and 1245 females, respectively. Cox regression models were used to assess the association between LDL-C and mortality. The effect of PH reversal on LDL-C levels was assessed in 34 patients with chronic thromboembolic pulmonary hypertension (CTEPH) undergoing invasive treatment. LDL-C was lower in both PAH (2.6 ± 0.8 mmol/l) and CTEPH (2.7 ± 0.7 mmol/l) patients when compared to controls (3.2 ± 1.1 mmol/l, p < 0.001). In PAH patients lower LDL-C significantly predicted death (HR:0.44/1 mmol/l, 95%CI:0.26-0.74, p = 0.002) after a median follow-up time of 33(21-36) months. In the CTEPH group, LDL-C increased (from 2.6[2.1-3.2] to 4.0[2.8-4.9]mmol/l, p = 0.01) in patients with PH reversal but remained unchanged in other patients (2.4[2.2-2.7] vs 2.3[2.1-2.5]mmol/l, p = 0.51). We concluded that LDL-C level is low in patients with PAH and is associated with an increased risk of death. Reversal of PH increases LDL-C levels.