No praise for folly: genomics will never be useful in arterial thrombosis

A decade of progress on the genetic basis of coronary artery disease. Practical insights for the internist

Clinicians are well aware of the importance of a positive family history for coronary artery disease (CAD). Nonetheless, elucidation of the genetic basis of CAD has long proven difficult. The scenario changed in the last decade through the application of modern genomic technologies, like genome-wide association studies (GWAS) and next generation sequencing (NGS). GWAS have discovered over 60 common variants highly associated with CAD. For predictive purposes, such variants have been used to build up Genetic Risk Scores (GRSs), but their incorporation into classical prediction models does not appear substantially outperform the simple addition of family history. To date, the only strong case for the utility of incorporating genetic testing into clinical practice is represented by the diagnosis of Familial Hypercholesterolemia (FH). On the other hand, utilization of genomic techniques has driven formidable advances into the knowledge of CAD pathophysiology, particularly by addressing controversies on the causality of some lipid fractions that had long remained unsolved because of limitations of observational epidemiology. For example, NGS-derived rare variants with strong functional effects on key-genes like ANGPTL4, APOA5, APOC3, LPL, and SCARB1, have proven useful as proxies to demonstrate the causality of triglyceride-rich lipoproteins (TRLs) at variance with HDL-cholesterol concentration, thus contributing to tear down a dogma from classical epidemiology. Moreover, such variants have paved the way for the development of new biologic drugs (i.e. monoclonal antibodies or antisense oligonucleotides) targeting key proteins like PCSK9, Lipoprotein_(a), and apolipoprotein C3. Such drugs are currently under active investigation, with first results being extremely promising.

Prothrombotic gene variation and new vascular events after cerebral ischemia of arterial origin

BACKGROUND

Several genetic variants involved in hemostasis have been associated with ischemic stroke or myocardial infarction (MI). Stroke patients who carry a prothrombotic genotype may also be at increased risk for subsequent vascular events.

PATIENTS AND METHODS

We included 887 patients with non-disabling cerebral ischemia of arterial origin, who were referred to the University Medical Center Utrecht in the Netherlands between 1995 and 2005 and followed them for the occurrence of ischemic stroke, MI or death. The primary outcome was a composite of death from all vascular causes, non-fatal ischemic stroke, non-fatal MI, whichever happened first. We selected 22 prothrombotic variants in 14 genes that were previously associated with ischemic stroke or MI or had evidence of functionality.

RESULTS

During a 4.6-year mean follow-up period new vascular events occurred in 135 patients (annual event rate 3.3%). None of the 22 variants was associated with the occurrence of new vascular events. Eight additional analyses with secondary outcomes or among subgroups revealed four associations that were likely to be false positive after accounting for multiple testing.

CONCLUSIONS

In this cohort, prothrombotic genetic variants do not affect the risk of new vascular events after cerebral ischemia of arterial origin. This study does not support the use of prothrombotic genetic variants to identify stroke patients at increased risk for new vascular events or to guide antithrombotic treatment.