Assessment of practical applicability and clinical relevance of a commonly used LDL-C polygenic score in patients with severe hypercholesterolemia

Background and aims: Low-density lipoprotein cholesterol (LDL-C) levels vary in patients with familial hypercholesterolemia (FH) and can be explained by a single deleterious genetic variant or by the aggregate effect of multiple, common small-effect variants that can be captured in a polygenic score (PS). We set out to investigate the contribution of a previously published PS to the inter-individual LDL-C variation and coronary artery disease (CAD) risk in patients with a clinical FH phenotype. Methods: First, in a cohort of 628 patients referred for genetic FH testing, we evaluated the distribution of a PS for LDL-C comprising 12 genetic variants. Next, we determined its association with coronary artery disease (CAD) risk using UK Biobank data. Results: The mean PS was higher in 533 FH-variant-negative patients (FH/M-) compared with 95 FH-variant carriers (1.02 vs 0.94, p < 0.001). 39% of all patients had a PS equal to the top 20% from a population-based reference cohort and these patients were less likely to carry an FH variant (OR 0.22, 95% CI 0.10–0.48) compared with patients in the lowest 20%. In UK Biobank data, the PS explained 7.4% of variance in LDL-C levels and was associated with incident CAD. Addition of PS to a prediction model using age and sex and LDL-C did not increase the c-statistic for predicting CAD risk. Conclusions: This 12-variant PS was higher in FH/M- patients and associated with incident CAD in UK Biobank data. However, the PS did not improve predictive accuracy when added to the readily available characteristics age, sex and LDL-C, suggesting limited discriminative value for CAD

Is mipomersen ready for clinical implementation? a transatlantic dilemma

Mipomersen has been approved by the US Food and Drug Administration as an orphan drug for patients with homozygous familial hypercholesterolemia (HoFH). In contrast, the European Medicines Agency advised negatively on the use of mipomersen. In this review, we discuss the efficacy and safety considerations for this discrepancy. On the basis of the results of clinical trials with mipomersen, safety concerns have been raised regarding cardiovascular risk reduction and development of hepatic steatosis. In addition, (long-term) tolerability concerns have been raised predominantly regarding injection site reactions. A pooled analysis of cardiovascular events in phase III trials with mipomersen did not provide evidence for either a positive or negative effect on cardiovascular disease. Although long-term studies with mipomersen are eagerly awaited, hepatic fat content appears to stabilize after 6-12 months notwithstanding continued mipomersen administration. HoFH is a disease with an unmet medical need for new lipid-lowering therapies. On the basis of a mean 2.9 mmol/l LDL-cholesterol reduction, mipomersen is expected to reduce cardiovascular risk in HoFH. Available evidence suggests that the fat accumulation associated with this treatment differs from steatohepatitis, which is a progressive and damaging liver disease. No evidence is available suggesting that injection site reactions because of mipomersen treatment will result in safety issue

Sirolimus-eluting stents to abolish intimal hyperplasia and improve flow in porcine arteriovenous grafts - A 4-week follow-up study

Background - The patency of arteriovenous ( AV) expanded polytetrafluoroethylene (ePTFE) hemodialysis grafts is severely compromised by intimal hyperplasia (IH) at the venous anastomosis and in the venous outflow tract. We addressed the potential of primary placement of a sirolimus-eluting stent (SES) in a validated porcine model. Methods and Results - In 25 pigs, ePTFE AV grafts were created bilaterally between the carotid artery and the jugular vein, whereupon a self-expandable nitinol stent ( 14 SESs and 11 bare-metal stents) was implanted over the venous anastomosis in 1 of the 2 grafts. After exclusion of technical failures and 1 unilateral occlusion, 16 pigs ( 9 SESs and 7 bare-metal stents) were included for further analysis. After 28 days, we measured graft flow and performed quantitative angiography. The pigs were then euthanized, and grafts with adjacent vessels were excised for histological analysis. Minimal luminal diameter was substantially larger in the SES group compared with unstented controls ( 5.9 +/- 0.2 versus 3.8 +/- 0.4 mm, respectively, P = 0.01), which was accompanied by more prominent graft flow ( SES, 1360 +/- 89 mL/min versus unstented, 861 +/- 83 mL/min, P = 0.05). IH at the venous anastomosis was 77% less in the SES group compared with unstented controls (0.44 +/- 0.05 versus 1.92 +/- 0.5 mm(2), respectively, P = 0.01), whereas IH increased markedly when bare-metal stents were used (5.7 +/- 1.4 mm(2), P = 0.05). Conclusions - SESs in the venous outflow of AV grafts significantly reduce IH and increase vessel diameter and graft flow compared with unstented grafts. These findings suggest that SESs have the potential to improve primary patency of AV grafts in hemodialysis patients

A six question screen to facilitate primary cardiovascular disease prevention

Background: European guidelines on primary prevention of cardiovascular disease (CVD) recommend the SCORE risk charts for determining CVD risk, which include blood pressure and serum cholesterol as risk parameters. To facilitate cost-effective large-scale screening, we aimed to construct a risk score with 'non-invasive' parameters as a first screening step to identify persons at increased CVD risk requiring further risk assessment. Methods: We used data of Dutch employees from 25 organisations participating in a health risk assessment between August 2007 and January 2013. Backward multivariate logistic regression analysis was employed to select non-invasive, independent predictors of high CVD risk, defined as the 10-year risk of fatal CVD of >= 5 % based on the SCORE formula. The total CVD risk score was calculated as the summed coefficients of the retained variables. Results: Data of 6189 male participants was used for the development and validation of the risk score. Age, tobacco use, history of hypertension, alcohol consumption, BMI, and waist circumference were independent predictors of high CVD risk. Ten-fold cross-validation resulted in an area under the curve of 0.95 (SE 0.01, 95 % confidence interval 0.94-0.96). A cut-off score >= 45 on the CVD risk score yielded a sensitivity of 0.93, and a specificity of 0.85. Conclusions: We developed a simple, non-invasive risk score that accurately identifies persons at increased CVD risk according to the SCORE formula in a population of working men. The risk score enables a stepwise approach in large screening programmes, strongly reducing the number of persons that require full risk estimation including blood pressure and cholesterol measures