From proprotein convertase subtilisin/kexin type 9 to its inhibition: state-of-the-art and clinical implications

LDL-C Reduction with Evolocumab Among Patients with ASCVD in China: Real-World Evidence from Tianjin Metropolitan Area

INTRODUCTION

Clinical trials have shown that adding evolocumab to statin therapy reduces low-density lipoprotein cholesterol (LDL-C) levels by approximately 60%. Given differences in patient characteristics and standards of care between trial and real-world settings, we conducted a cohort study to evaluate the LDL-C reduction achieved with evolocumab in clinical practice of China.

METHODS

The data source was the Tianjin Regional Healthcare Database (TRHD), which includes linked electronic health records (EHR) of public hospitals serving over 15 million residents in the Tianjin metropolitan area. The study cohort included adult patients with atherosclerotic cardiovascular disease (ASCVD) who added evolocumab to their statin therapy between 2019 and 2023. Key inclusion criteria were use of the same statin intensity before and after evolocumab initiation and available LDL-C values at baseline (within 90 days before initiation) and follow-up (15-90 days after initiation). Descriptive statistics were used to analyze LDL-C change between baseline and follow-up. To provide the context for evolocumab use and for study method assessment, we included another cohort of patients with stable statin intensity (unchanged for at least 180 days)-a cohort with minimal clinical expectation of further LDL-C change over time.

RESULTS

At baseline, the median (interquartile range [IQR]) LDL-C level was 3.44 (2.73-4.15) mmol/L in the evolocumab cohort (n = 395) and 2.20 (1.72-2.92) mmol/L in the stable statin cohort (n = 4160). At follow-up, the mean (95% confidence interval [CI]) percentage reduction in LDL-C levels was 63.0% (60.5-65.5%) in the evolocumab cohort and 2.5% (0.3-4.7%) in the stable statin cohort.

CONCLUSIONS

LDL-C reductions in patients who added evolocumab to statin therapy in real-world clinical practice in China align with reductions observed in clinical trials.

Early and short-term use of proprotein convertase anti-subtilisin-kexin type 9 inhibitors on coronary plaque stability in acute coronary syndrome

Aims

Proprotein convertase anti-subtilisin-kexin type 9 inhibitors (PCSK9Is) improve plaque volume and composition and reduce major adverse coronary events in chronic coronary artery disease. We evaluated the effects of the short-term use of PCSK9Is on coronary plaque stability in patients with acute coronary syndrome (ACS) using optical coherence tomography (OCT).

Methods and results

This is a multicentre, open-label randomized controlled trial. The enrolled 80 subjects met the inclusion criteria. Of these, 52 patients (age 60 ± 11 years, 38 men, 14 women) with ST-elevated ACS had undergone successful primary percutaneous coronary intervention with LDL-cholesterol (LDL-C) levels > 70 mg/dL while receiving high-intensity statins. Participants were randomly assigned to the PCSK9I group (evolocumab 420 mg for 3 months, n = 29) or the standard of care (SoC) group (n = 23). Optical coherence tomography was performed at baseline (BL) and 3 and 9 months after randomization to assess lipid-rich plaques in non-culprit lesions. The change in the minimum fibrous cap thickness (MFCT) from BL to 9 months was the primary endpoint. The percentage change in LDL-C levels from BL to 3 months was significantly greater in the PCSK9I group (-67.8 ± 21.5% in the PCSK9I group vs. -16.3 ± 21.8% in the SoC group; P < 0.0001), and the difference between the two groups disappeared from BL to 9 months (-20.0 ± 37.8% in the PCSK9I group vs. -6.7 ± 34.2% in the SoC group; P = 0.20). The changes in MFCT from BL to 9 months were significantly greater in the PCSK9I group, even after PCSK9I discontinuation {100 μm [interquartile range (IQR): 45-180 μm] vs. 50 μm [IQR: 0-110 μm]; P = 0.032}.

Conclusion

Combination treatment with PCSK9Is and statins resulted in more marked plaque stabilization after ACS than SoC alone, and this effect persisted for 6 months after PCSK9I discontinuation.

Registration

Adage-Joto study, UMIN ID No. 26516.

Proprotein convertase subtilisin/kexin type 9 inhibitor ameliorates cerebral ischemia in mice by inhibiting inflammation

OBJECTIVES

To investigate the potential protective effects of evolocumab, a proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitor, on ischemic stroke and its underlying mechanisms.

MATERIALS AND METHODS

We established a mouse model with distal middle cerebral artery occlusion. We evaluated the therapeutic effects through neurological function and infarct size, while the underlying mechanisms were elucidated using western blotting and real-time polymerase chain reaction.

RESULTS

Evolocumab improved neurological recovery, reduced the infarct volume, suppressed the activation of Toll-like receptor (TLR) 4 and nuclear factor-kappa B (NF-κB), and attenuated the increased levels of IL-1β and TNF-α after cerebral ischemia.

CONCLUSION

Evolocumab protects against cerebral ischemic injury by inhibiting inflammation. Therefore, the TLR4/NF-кB pathway may represent a major mechanism in ischemic stroke.

A Practical Statin Recommendation System Based on Real-World Data to Improve LDL-C Management in Secondary Prevention

ABSTRACT

Statins are considered the cornerstone of secondary prevention in patients with atherosclerotic cardiovascular disease (ASCVD). However, many patients fail to achieve the guide-recommended goal of low-density lipoprotein cholesterol (LDL-C) after statin monotherapy, leading to a high residual risk of cardiovascular events. Owing to individual differences in statin therapy, it is possible first to consider changing the type of statin before adding nonstatin medications in certain patients to improve LDL-C management. We developed and evaluated a statin recommendation system using real-world data. Ensemble learning was performed to develop the recommendation system that integrated the output results of support vector machines (SVM) and the similarity of patients. Model performance was assessed to investigate whether treatment according to the recommended model would increase the proportion of patients with the primary end point. Finally, a total of 3510 patients were enrolled in the development and validation of the recommender system. Of them, 1240 patients received atorvastatin (35.3%), 1714 patients received rosuvastatin (48.8%), and 556 patients received pitavastatin (15.8%). The statin recommendation system could significantly improve LDL-C target rate achievement in the recommended treatment group compared with the nonrecommended treatment group in the validation set (50.8% vs. 31.5%, P < 0.001). This study demonstrated that the statin recommendation system could significantly improve the achievement of LDL-C goals in ASCVD patients, providing a new approach to improve LDL-C management.

PCSK9 Inhibition During the Inflammatory Stage of SARS-CoV-2 Infection

BACKGROUND

The intensity of inflammation during COVID-19 is related to adverse outcomes. Proprotein convertase subtilisin/kexin type 9 (PCSK9) is involved in low-density lipoprotein receptor homeostasis, with potential influence on vascular inflammation and on COVID-19 inflammatory response.

OBJECTIVES

The goal of this study was to investigate the impact of PCSK9 inhibition vs placebo on clinical and laboratory outcomes in patients with severe COVID-19.

METHODS

In this double-blind, placebo-controlled, multicenter pilot trial, 60 patients hospitalized for severe COVID-19, with ground-glass opacity pneumonia and arterial partial oxygen pressure to fraction of inspired oxygen ratio ≤300 mm Hg, were randomized 1:1 to receive a single 140-mg subcutaneous injection of evolocumab or placebo. The primary endpoint was death or need for intubation at 30 days. The main secondary endpoint was change in circulating interleukin (IL)-6 at 7 and 30 days from baseline.

RESULTS

Patients randomized to receive the PCSK9 inhibitor had lower rates of death or need for intubation within 30 days vs placebo (23.3% vs 53.3%, risk difference: -30%; 95% CI: -53.40% to -6.59%). Serum IL-6 across time was lower with the PCSK9 inhibitor than with placebo (30-day decline: -56% vs -21%). Patients with baseline IL-6 above the median had lower mortality with PCSK9 inhibition vs placebo (risk difference: -37.50%; 95% CI: -68.20% to -6.70%).

CONCLUSIONS

PCSK9 inhibition compared with placebo reduced the primary endpoint of death or need for intubation and IL-6 levels in severe COVID-19. Patients with more intense inflammation at randomization had better survival with PCSK9 inhibition vs placebo, indicating that inflammatory intensity may drive therapeutic benefits. (Impact of PCSK9 Inhibition on Clinical Outcome in Patients During the Inflammatory Stage of the COVID-19 [IMPACT-SIRIO 5]; NCT04941105).

Pharmaco-invasive therapy: Early implementation of statins and proprotein convertase subtilisin/kexin type 9 inhibitors after acute coronary syndrome

Elevated LDL-cholesterol (LDL-C) plays a major role in atheroma formation and inflammation. Medical therapy to lower elevated LDL-C is the cornerstone for reducing the progression of atherosclerotic cardiovascular disease. Statin therapy, and more recently, other drugs such as proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors, have proven efficacy in long-term lowering of LDL-C and therefore diminish cardiovascular risk. During an acute coronary syndrome (ACS), a systemic inflammatory response can destabilize other non-culprit atherosclerotic plaques. Patients with these vulnerable plaques are at high risk of experiencing recurrent cardiovascular events in the first few years post-ACS. Initiating intensive LDL-C lowering therapy in these patients with statins or PCSK9 inhibitors can be beneficial via several pathways. High-intensity statin therapy can reduce inflammation by directly lowering LDL-C, but also through its pleiotropic effects. PCSK9 inhibitors can directly lower LDL-C to recommended guideline thresholds, and could have additional effects on inflammation and plaque stability. We discuss the potential role of early implementation of statins combined with PCSK9 inhibitors to influence these cascades and to mediate the associated cardiovascular risk, over and above the well-known long-term beneficial effects of chronic LDL-C lowering.

Effect of alirocumab and evolocumab on all-cause mortality and major cardiovascular events: A meta-analysis focusing on the number needed to treat

AIMS

The efficacy of anti-proprotein convertase subtilisin/Kexin type 9 (PCSK9) monoclonal antibodies in patients with atherosclerotic cardiovascular disease (ASCVD) remains unclear. Therefore, this study aims to assess the effect of PCSK9 inhibitors (alirocumab and evolocumab) on ASCVD patients considering the number needed to treat (NNT).

METHODS

We reviewed randomized controlled trials (RCTs) which compared the effects of alirocumab or evolocumab and placebo or standards of care. All articles were published in English up to May 2022. Using random effect models, we estimated risk ratios (RRs), NNT, and 95% confidence intervals (CI).

RESULTS

We incorporated 12 RCTs with 53 486 patients total, of which 27 674 received PCSK9 inhibitors and 25 812 received placebos. The mean follow-up duration was 1.56 years. The effect of PCSK9 inhibitors on major adverse cardiovascular events (MACE) was statistically significant, and the corresponding mean NNT was 36. Alirocumab reduced the risk of MACE, stroke, and coronary revascularization; the corresponding mean NNT were 37, 319, and 107, respectively. Evolocumab positively affected MACE, myocardial infarction, stroke, and coronary revascularization; the corresponding mean NNT were 32, 78, 267, and 65, respectively. The effects of alirocumab or evolocumab on all-cause mortality and cardiovascular mortality were not statistically significant.

CONCLUSION

This study suggests that preventing one patient from MACE needed to treat 36 patients with ASCVD with PCSK9 inhibitors for 1.56 years. Both alirocumab and evolocumab reduced MACE, stroke, and coronary revascularization. Evolocumab had a positive effect on myocardial infarction, but no effects were noted for alirocumab. In addition, alirocumab may not be as effective as evolocumab. NNT visualizes the magnitude of efficacy to assist in clinical decisions.

SYSTEMATIC REVIEW REGISTRATION

[https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=344908], identifier [CRD42022344908].

The relationship between pulse pressure with plasma PCSK9 and interleukin-6 among patients with acute ischemic stroke and dyslipidemia

BACKGROUND AND PURPOSE

A high plasma concentration of proprotein convertase subtilisin/kexin type 9 is characteristic of a prothrombotic state in cardiovascular diseases. Elevated inflammatory markers, such as interleukin-6, are associated with worse outcomes after ischemic stroke. We aimed to study the role of plasma PCSK9 and IL-6 in acute ischemic stroke with dyslipidemia.

METHODS

We divided 123 enrolled patients with first-ever acute ischemic stroke into normotensive and high blood pressure groups and further into high and low pulse pressure subgroups. Clinical characteristics and inflammatory and metabolic parameters, including plasma PCSK9 and IL-6, were recorded.

RESULTS

After the analysis of the normotensive and BP groups, there were positive correlations between PP and carotid stenosis (P = 0.031) and plaque numbers (P = 0.013) and between National Institute of Health Stroke Scale scores (P = 0.019) and carotid stenosis severity (P = 0.021) and resistance index (P = 0.04). There was a significant association between plasma cholesterol and PCSK9 (P = 0.044) in the low PP subgroup and IL-6 (P = 0.042) in the high PP subgroup.

CONCLUSIONS

Our findings indicated that plasma PCSK9 levels were associated with the low PP subgroup, while IL-6 was associated with the high PP subgroup. Dyslipidemia control is also necessary for those who had a stroke and who have high PP. Further investigation to assess the role of PCSK9 and IL-6 in patients with stroke is required for early treatment and secondary prevention.

A novel prothrombotic role of proprotein convertase subtilisin kexin 9: the generation of procoagulant extracellular vesicles by human mononuclear cells

BACKGROUND

Proprotein convertase subtilisin kexin 9 (PCSK9) is a serin protease synthesized mainly in the liver that binds the receptor of low-density lipoprotein and promotes its degradation in lysosomes. PCSK9 is considered a promising target for the development of new therapies for the treatment of hypercholesterolemia and related cardiovascular diseases. Extracellular vesicles represent a heterogeneous population of vesicles, ranging in size between 0.05 and 1 μm involved in numerous pathophysiological processes, including blood coagulation. We investigated whether PCSK9 stimulation induces the release of procoagulant extracellular vesicles from human mononuclear cells (PBMCs) and THP-1 cells.

METHODS AND RESULTS

PBMCs and THP-1 cells were stimulated whit PCSK9, the generation of EV was assessed by the prothrombinase assay and by cytofluorimetric analysis. EV-associated tissue factor activity was assessed by a one-stage clotting assay. PCSK9 induced an increase in extracellular generation by PBMCs and THP-1 cells as well as an increase in extracellular vesicle-associated tissue factor. Pre-treatment with inhibitors of the toll like receptor, TLR4 (C34), and of NF-κB signaling (BAY 11-7082), downregulated PCSK9-induced extracellular vesicle generation and of extracellular- bound tissue factor. Similar effect was obtained by an anti-PCSK9 human-monoclonal antibody.

CONCLUSIONS

PCSK9-mediated generation of procoagulant EV could contribute to increase the prothrombotic status in patients with cardiovascular diseases.

Plasmatic PCSK9 Levels Are Associated with Very Fast Progression of Asymptomatic Degenerative Aortic Stenosis

The aim of this work was to study the association of potential biomarkers with fast aortic stenosis (AS) progression. Patients with moderate-to-severe AS were classified as very fast progressors (VFP) if exhibited an annualized change in peak velocity (aΔVmax) ≥0.45m/s/year and/or in aortic valve area (aΔAVA) ≥-0.2cm2/year. Respective cut-off values of ≥0.3m/s/year and ≥-0.1cm²/year defined fast progressors (FP), whereas the remaining patients were non-fast progressors (non-FP). Baseline markers of lipid metabolism, inflammation, and cardiac overload were determined. Two hundred and nine patients (97 non-FP, 38 FP, and 74 VFP) were included. PCSK9 levels were significantly associated with VFP (OR 1.014 [95%CI 1.005-1.024], for every 10 ng/mL), as were active smoking (OR 3.48) and body mass index (BMI, OR 1.09), with an AUC of 0.704 for the model. PCSK9 levels, active smoking, and BMI were associated with very fast AS progression in our series, suggesting that inflammation and calcification participate in disease progression.

Effect of PCSK9 E670G and R46L Polymorphisms on Major Adverse Cardio-Cerebrovascular Events in Patients with ST-Segment Elevation Myocardial Infarction Undergoing Primary Percutaneous Coronary Intervention

Major adverse cardio-cerebrovascular events (MACCE) in ST-segment elevation myocardial infarction (STEMI) are still high, although there have been advances in pharmacology and interventional procedures. Proprotein convertase subtilisin/Kexin type 9 ( PCSK9 ) is a serine protease regulating lipid metabolism associated with inflammation in acute coronary syndrome. The MACCE is possibly related to polymorphisms in PCSK9 . A prospective cohort observational study was designed to confirm the association between polymorphism of E670G and R46L in the PCSK9 gene with MACCE in STEMI. The Cox proportional hazards model and Spearman correlation were utilized in the study. The Genotyping of PCSK9 and ELISA was assayed. Sixty-five of 423 STEMI patients experienced MACCE in 6 months. The E670G polymorphism in PCSK9 was associated with MACCE (hazard ratio = 45.40; 95% confidence interval: 5.30-390.30; p  = 0.00). There was a significant difference of PCSK9 plasma levels in patients with previous statin consumption (310 [220-1,220] pg/mL) versus those free of any statins (280 [190-1,520] pg/mL) ( p  = 0.001). E670G polymorphism of PCSK9 was associated with MACCE in STEMI within a 6-month follow-up. The plasma PCSK9 level was higher in statin users.

Indirect comparison of the efficacy and safety of alirocumab and evolocumab: a systematic review and network meta-analysis

AIMS

Although alirocumab and evolocumab have both been associated with improved outcomes in patients with dyslipidaemia or established atherosclerotic cardiovascular disease, data on their respective performances are scarce. This study aimed at providing an indirect comparison of the efficacy and safety of alirocumab vs. evolocumab.

METHODS AND RESULTS

We conducted a systematic review and network meta-analysis of randomized trials comparing alirocumab or evolocumab to placebo with consistent background lipid-lowering therapy up to November 2018. We estimated the relative risk (RR) and the 95% confidence intervals (CIs) using fixed-effect model in a frequentist pairwise and network meta-analytic approach. A total of 30 trials, enrolling 59 026 patients were included. Eligibility criteria varied significantly across trials evaluating alirocumab and evolocumab. Compared with evolocumab, alirocumab was associated with a significant reduction in all-cause death (RR 0.80, 95% CI 0.66-0.97) but not in cardiovascular death (RR 0.83, 95% CI 0.65-1.05). This study did not find any significant differences in myocardial infarction (RR 1.15, 95% CI 0.99-1.34), stroke (RR 0.96, 95% CI 0.71-1.28), or coronary revascularization (RR 1.13, 95% CI 0.99-1.29) between the two agents. Alirocumab was associated with a 27% increased risk of injection site reaction compared to evolocumab; however, no significant differences were found in terms of treatment discontinuations, systemic allergic reaction, neurocognitive events, ophthalmologic events, or new-onset of or worsening of pre-existing diabetes.

CONCLUSION

Alirocumab and evolocumab share a similar safety profile except for injection site reaction. No significant differences were observed across the efficacy endpoints, except for all-cause death, which may be related to the heterogeneity of the studied populations treated with the two drugs.

Sex Differences Associated With Circulating PCSK9 in Patients Presenting With Acute Myocardial Infarction

A limited number of studies have explored whether the role of circulating proprotein convertase subtilisin/kexin type 9 (PCSK9) in the pathogenesis of acute myocardial infarction (AMI) is sex specific. The purpose of the present study was to examine sex differences in plasma PCSK9 in Chinese patients with AMI. In this study, a total of 281 records from patients presenting with AMI were analyzed.We compared hospital data and plasma PCSK9 levels by sex difference for inpatients presenting with AMI. After 1 year of follow-up, major adverse cardiac events(MACE) were recorded. A Cox proportional hazards model was used to calculate hazard ratios with 95% confidence intervals. We found that, compared with male groups, PCSK9 levels were higher in female patients not only for overall patients with AMI but also for patients with ST-elevation myocardial infarction (STEMI) (median: 273.6 [215.6–366.8] vs. 325.1 [247.5–445.3] ng/ml, P = 0.0136; 273.4 [215.6–369.7] vs. 317.1 [249.6–450.1], P = 0.0275, respectively). The cumulative incidence of cardiac death and 1-year MACE were significantly higher in the female group compared with male group (10% vs. 2.74%, P = 0.025; 15% vs. 4.11%, P = 0.0054, respectively). On multivariate Cox regression analysis, female sex, total triglyceride, glycosylated hemoglobin A, and homocysteic acid were independent risk factors of 1-year MACE. There was no significant correlation between PCSK9 and 1-year MACE in total AMI patients. In conclusion, PCSK9 levels and 1-year MACE were higher in women with AMI than in men with AMI, however, female sex but not PCSK9 were significant correlated with the 1-year MACE. The clinical implications of this finding are worthy of further investigations and must be confirmed in larger cohorts.

Familial Hypercholesterolemia: New Horizons for Diagnosis and Effective Management

Familial hypercholesterolemia (FH) is a common genetic cause of premature cardiovascular disease (CVD). The reported prevalence rates for both heterozygous FH (HeFH) and homozygous FH (HoFH) vary significantly, and this can be attributed, at least in part, to the variable diagnostic criteria used across different populations. Due to lack of consistent data, new global registries and unified guidelines are being formed, which are expected to advance current knowledge and improve the care of FH patients. This review presents a comprehensive overview of the pathophysiology, epidemiology, manifestations, and pharmacological treatment of FH, whilst summarizing the up-to-date relevant recommendations and guidelines. Ongoing research in FH seems promising and novel therapies are expected to be introduced in clinical practice in order to compliment or even substitute current treatment options, aiming for better lipid-lowering effects, fewer side effects, and improved clinical outcomes.

Association between plasma levels of PCSK9 and the presence of coronary artery disease in Japanese

The ability of pro-protein convertase subtilisin/kexin type 9 (PCSK9) levels to predict the presence or severity of coronary artery disease (CAD) remains controversial. The purpose of this study was to investigate these associations. We enrolled 393 patients who were clinically suspected to have CAD or who had at least one cardiac risk factor and underwent multidetector-row computed tomography coronary angiography. The presence of CAD (≥50% coronary stenosis), the number of significantly stenosed coronary vessels, and plasma levels of PCSK9 by ELISA were analyzed. Plasma PCSK9 levels (log-transformed data) were significantly associated with the presence of CAD. Next, we divided the patients into two groups (non-statin and statin groups) according to statin treatment. PCSK9 levels in the non-statin group were significantly lower than those in the statin group. There were no significant differences in PCSK9 levels between the absence and presence of CAD in the statin group. However, in the non-statin group, PCSK9 levels in patients with CAD were significantly higher than those in patients without CAD. PCSK9 levels, in addition to age, gender, BMI, DM and HDL-C, were independently associated with the presence of CAD by a multivariable analysis. In conclusion, our results demonstrated that plasma PCSK9 levels may be a marker for evaluating the presence of CAD.

Dyslipidemias and Cardiovascular Prevention: Tailoring Treatment According to Lipid Phenotype

PURPOSE OF REVIEW

This study aimed to present the current information on the genetic background of dyslipidemias and provide insights into the complex pathophysiological role of several plasma lipids/lipoproteins in the pathogenesis of atherosclerotic cardiovascular disease. Furthermore, we aim to summarize established therapies and describe the scientific rationale for the development of novel therapeutic strategies.

RECENT FINDINGS

Evidence from genetic studies suggests that besides lowering low-density lipoprotein cholesterol, pharmacological reduction of triglyceride-rich lipoproteins, or lipoprotein(a) will reduce risk for coronary heart disease. Dyslipidemia, in particular hypercholesterolemia, is a common clinical condition and represents an important determinant of atherosclerotic vascular disease. Treatment decisions are currently guided by the causative lipid phenotype and the presence of other risk factors suggesting a very high cardiovascular risk. Therefore, the identification of lipid disorders and the optimal combination of therapeutic strategies provide an outstanding opportunity for reducing the onset and burden of cardiovascular disease.

Association of PCSK9 with platelet reactivity in patients with acute coronary syndrome treated with prasugrel or ticagrelor: The PCSK9-REACT study

BACKGROUND

Circulating proprotein convertase subtilisin/kexin type 9 (PCSK9) enzyme might be associated with increased activation of platelets. We aimed to assess the relationship between PCSK9 levels, platelet reactivity and ischemic outcomes.

METHODS

Consecutive ACS patients receiving prasugrel or ticagrelor and undergoing percutaneous coronary intervention (PCI) were enrolled in a prospective, observational study. Adenosine diphosphate (ADP)-induced platelet aggregation was determined by Multiplate Analyzer in the maintenance phase of treatment with prasugrel or ticagrelor. Major adverse cardiovascular events (MACEs) defined as composite of cardiovascular death, myocardial infarction, unstable angina, stent thrombosis, repeat revascularization, ischemic stroke were evaluated at 12months.

RESULTS

A direct association was found between increased PCSK9 serum levels and platelet reactivity (r=0.30; p=0.004). When assessed according to tertile values of PCSK9, there was a significant increase in platelet reactivity in the upper vs lower tertile (p=0.02). Clinical outcome was available at follow-up in 178 subjects. In the upper PCSK9 tertile 13/59 (22.03%) patients experienced a clinical MACE at one year, vs 2/59 (3.39%) patients in the lower PCSK9 tertile. At one-year follow-up, PCSK9 was independently associated with increased ischemic MACEs: hazard ratio for upper vs lower PCSK9-level tertile was 2.62 (95% confidence interval 1.24-5.52; p=0.01).

CONCLUSIONS

These findings suggest that increased PCSK9 levels are associated with higher platelet reactivity and are a possible predictor of ischemic events in ACS patients undergoing PCI.

New directions for pharmacotherapy in the treatment of acute coronary syndrome

INTRODUCTION

Acute coronary syndromes (ACS) are one of the leading causes of death worldwide. Several landmark trials, followed by a widespread introduction of new agents, have significantly improved ACS outcomes in recent years. However, despite the use of contemporary therapy, a substantial number of ACS patients continue to suffer from cardiovascular events. Areas covered: The aim of this review was to summarize available data on innovative drugs and pharmacological strategies that have potential to amend the current ACS therapy. We present the results of recent large clinical trials, as well as insights from ongoing phase III and phase IV studies, exploring the value of new strategies for the improvement of outcomes in ACS. Expert opinion: More potent platelet inhibition, more profound lipid reduction and possibly anti-inflammatory action are considered to have potential to further reduce the rates of adverse cardiovascular and thrombotic events in ACS patients. 'Hit fast, hit hard' approach regarding novel antiplatelet and lipid-lowering therapy seems attractive, but it has to be considered that these strategies may be associated with increased adverse events rate. Introduction of cangrelor and ezetimibe, and potentially future recognition of proprotein convertase subtilisin/kexin type 9 antibodies, are likely to alter the landscape of ACS pharmacotherapy.

Prediction of cardiovascular events with levels of proprotein convertase subtilisin/kexin type 9: A systematic review and meta-analysis

BACKGROUND AND AIMS

Inhibition of proprotein convertase subtilisin/kexin type 9 (PCSK9) reduces atherogenic lipoproteins and could lead to reduction of cardiovascular (CV) events. However, it is unclear whether blood PCSK9 levels predict future CV events. We performed a meta-analysis of all longitudinal studies to determine the ability of PCSK9 levels to predict risk of future CV events.

METHODS

A comprehensive search of electronic databases was conducted up to February 2016. Longitudinal studies that reported events or relative risk (RR) estimates with 95% confidence intervals (CI) were included.

RESULTS

All 9 studies included (12,081 participants, mean follow-up 6.62 years) reported results on total CV events. The pooled RR of total CV events for an increase in baseline PCSK9 by 1 standard deviation (SD) was 1.098 (95% CI, 1.02-1.18), corresponding to a risk increase of 10% (Z = 2.43, p = 0.015). The pooled RR of total CV events for subjects categorized in the highest tertile of baseline PCSK9 was 1.228 (95% CI, 1.035-1.457), corresponding to a risk increase of 23% (Z = 2.35, p = 0.019). When pooled estimates were derived independently for low- and high-CV risk populations, baseline PCSK9 levels predicted total CV events only in apparently healthy subjects (RR = 1.13, 95% CI: 1.050-1.222, Z = 3.21, p = 0.001) and not in populations with established CV or renal disease (RR = 1.09, 95% CI: 0.961-1.23, Z = 1.33, p = 0.182).

CONCLUSIONS

PCSK9 levels are modestly but significantly associated with increased risk of total CV events. These results suggest a predictive role of PCSK9 levels on CV health and support the possible clinical role of PCSK9 inhibitors.