Genetics and cardiovascular disease: a policy statement from the American Heart Association

Economic evaluation of Cardio inCode®, a clinical-genetic function for coronary heart disease risk assessment

BACKGROUND

A clinical–genetic function (Cardio inCode®) was generated using genetic variants associated with coronary heart disease (CHD), but not with classical CHD risk factors, to achieve a more precise estimation of the CHD risk of individuals by incorporating genetics into risk equations [Framingham and REGICOR (Registre Gironí del Cor)].

OBJECTIVE

The objective of this study was to conduct an economic analysis of the CHD risk assessment with Cardio inCode®, which incorporates the patient’s genetic risk into the functions of REGICOR and Framingham, compared with the standard method (using only the functions).

METHODS

A Markov model was developed with seven states of health (low CHD risk, moderate CHD risk, high CHD risk, CHD event, recurrent CHD, chronic CHD, and death). The reclassification of CHD risk derived from genetic information and transition probabilities between states was obtained from a validation study conducted in cohorts of REGICOR (Spain) and Framingham (USA). It was assumed that patients classified as at moderate risk by the standard method were the best candidates to test the risk reclassification with Cardio inCode®. The utilities and costs (€; year 2011 values) of Markov states were obtained from the literature and Spanish sources. The analysis was performed from the perspective of the Spanish National Health System, for a life expectancy of 82 years in Spain. An annual discount rate of 3.5 % for costs and benefits was applied.

RESULTS

For a Cardio inCode® price of €400, the cost per QALY gained compared with the standard method [incremental cost-effectiveness ratio (ICER)] would be €12,969 and €21,385 in REGICOR and Framingham cohorts, respectively. The threshold price of Cardio inCode® to reach the ICER threshold generally accepted in Spain (€30,000/QALY) would range between €668 and €836. The greatest benefit occurred in the subgroup of patients with moderate–high risk, with a high-risk reclassification of 22.8 % and 12 % of patients and an ICER of €1,652/QALY and €5,884/QALY in the REGICOR and Framingham cohorts, respectively. Sensitivity analyses confirmed the stability of the study results.

CONCLUSIONS

Cardio inCode® is a cost-effective risk score option in CHD risk assessment compared with the standard method.

Use of the Corus® CAD Gene Expression Test for Assessment of Obstructive Coronary Artery Disease Likelihood in Symptomatic Non-Diabetic Patients

The determination of the underlying etiology of symptoms suggestive of obstructive coronary artery disease (CAD, ≥50% stenosis in a major coronary artery) is a common clinical challenge in both primary care and cardiology clinics. Usual care in low to medium risk patients often involves a family history, risk factor assessment, and then stress testing with or without non-invasive imaging. If positive, this is often followed by invasive coronary angiography (ICA). Despite extensive adoption of this usual care paradigm, more than 60% of patients referred for angiography do not have obstructive CAD. In order to robustly identify those symptomatic patients without obstructive CAD, who can avoid subsequent cardiac testing and look elsewhere for the cause of their symptoms, a recently described whole blood gene expression score (GES: Corus® CAD, CardioDx, Inc., Palo Alto, CA) has been developed and validated in two multi-center trials. This paper reviews the published literature and assessments by independent parties regarding the analytical and clinical validity as well as the clinical utility of the Corus® CAD test.

Effects of endothelial dysfunction on residual platelet aggregability after dual antiplatelet therapy with aspirin and clopidogrel in patients with stable coronary artery disease

BACKGROUND

Dual antiplatelet therapy with aspirin and clopidogrel is widely used in patients with coronary stents. High residual platelet reactivity (high RPR) after dual antiplatelet therapy is associated with increased cardiovascular events. Endothelial function could affect platelet reactivity in vivo. We hypothesized that endothelial dysfunction could be associated with high RPR after dual antiplatelet therapy in patients with stable coronary artery disease.

METHODS AND RESULTS

We screened patients with stable coronary artery disease for cytochrome P450 (CYP) 2C19 genotypes and enrolled 103 patients who lacked CYP2C19*2 or *3 loss-of-function allele to minimize the effect of this gene on high RPR. All patients received aspirin (100 mg/d) and clopidogrel (75 mg/d for long-term treatment or a loading dose of 300 mg) before the following tests. Platelet aggregability was assessed as P2Y12 reaction unit using the VerifyNow System. High RPR was defined as P2Y12 reaction unit ≥ 230. Peripheral endothelial function was expressed as reactive hyperemia index using reactive hyperemia peripheral arterial tonometry. Fifty-three patients exhibited high RPR. High RPR patients were significantly older, had higher levels of B-type natriuretic peptide, and were predominantly hypertensive compared with non-high RPR patients. Reactive hyperemia index was significantly lower in high RPR patients (0.46 ± 0.15) compared with non-high RPR patients (0.61 ± 0.18; P<0.001). Linear regression analysis demonstrated significant negative correlation between reactive hyperemia index and P2Y12 reaction unit (r=-0.32; P=0.001). Multivariable logistic regression analysis identified reactive hyperemia index as an independent and significant determinant of high RPR (odds ratio, 0.55; 95% confidence interval, 0.39-0.78; P=0.001).

CONCLUSIONS

In patients with stable coronary artery disease, endothelial function was significantly impaired in high RPR patients. Endothelial dysfunction is independently correlated with high RPR after dual antiplatelet therapy.

CLINICAL TRIAL REGISTRATION URL

http://www.umin.ac.jp/ctr. Unique identifier: UMIN000008239.

Using genetic testing to guide therapeutic decisions in cardiomyopathy

OPINION STATEMENT

Genetic analysis of human cardiomyopathy has rapidly transitioned from a strictly research endeavor to a diagnostic tool readily available to clinicians across the globe. In contemporary practice, genetic testing improves the efficiency of family evaluations and clarifies the etiology of ambiguous clinical presentations. The great promise of genetic diagnosis is to enable preventative therapies for individuals at high risk of future disease development, a strategy that is under active clinical investigation. However, in the present and future, careful interpretation of DNA sequence variation is critical, and can be ensured by referral to a specialized cardiovascular genetics clinic.

Genetic testing in the contemporary diagnosis of cardiomyopathy

The heritable cardiomyopathies are relatively common conditions that can lead to heart failure and sudden cardiac death. Family history collection, genetic testing and genetic counseling are recommended for these patients and families in multiple practice guidelines and consensus statements. Research discoveries and rapidly dropping costs of DNA sequencing technologies have resulted in the availability of multiple cardiomyopathy genetic testing panels. Genetic testing not only helps in determining the underlying etiology of idiopathic and familial cardiomyopathies, but is also a powerful tool in the determination of which relatives are at-risk and which are not. Both pre- and post-test genetic counseling is an imperative component of genetic testing, as there are many benefits and limitations of genetic testing that need discussed with each patient undergoing this process.

Genetic Counselors: An Important Resource for Families following a Young Sudden Cardiac Death

Sudden cardiac death is a tragic result of a number of cardiovascular diseases. While the majority of sudden cardiac death cases are in older individuals with coronary artery disease, victims also include younger people (those less than 40 years old). At least 40% of cases of young sudden death are attributable to genetic causes, including diagnoses such as long QT syndrome and hypertrophic cardiomyopathy. In 50% of young sudden death cases, there are no warning signs or family history of sudden death. These young sudden deaths are a tragedy for families and in many cases are devastating for communities as well. Awareness is spreading among medical examiners and cardiologists on how to assess and treat these families but few healthcare providers see cases routinely. The combination of an unexpected death and the burden of potentially having a genetic disease themselves leaves family members in a vulnerable and often overwhelming position. Genetic counselors, particularly those who specialize in cardiovascular disease, are uniquely qualified to help surviving family members navigate the medical and psychosocial issues present in these cases.