Evaluating novel cardiovascular risk factors: can we better predict heart attacks?

Myocardial infarction often occurs among persons without traditional risk factors, and it has been hypothesized that assessment of "novel" markers may help identify persons who are prone to premature atherothrombosis. However, when considering the clinical utility of screening for any new marker for cardiovascular disease, physicians should consider whether there is a standardized and reproducible assay for the marker of interest; whether there is a consistent series of prospective epidemiologic studies indicating that baseline elevations of the novel marker predict future risk; and whether assessment of the novel marker adds to the predictive value of other plasma-based risk factors, specifically, the ratio of total cholesterol to high-density lipoprotein cholesterol. In this article, these criteria are used to evaluate five promising markers of cardiovascular risk: lipoprotein(a), total plasma homocysteine, fibrinolytic capacity, fibrinogen, and high-sensitivity C-reactive protein. Background is also provided to assist physicians in deciding whether one or more of these novel markers deserve clinical consideration in general outpatient settings.     

Cancer‐like metabolism of the mammalian retina

The retina, like many cancers, produces energy from glycolysis even in the presence of oxygen. This phenomenon is known as aerobic glycolysis and eponymously as the Warburg effect. In recent years, the Warburg effect has become an explosive area of study within the cancer research community. The expanding knowledge about the molecular mechanisms underpinning the Warburg effect in cancer promises to provide a greater understanding of mammalian retinal metabolism and has motivated cancer researchers to target the Warburg effect as a novel treatment strategy for cancer. However, if the molecular mechanisms underlying the Warburg effect are shared by the retina and cancer, treatments targeting the Warburg effect may have serious adverse effects on retinal metabolism. Herein, we provide an updated understanding of the Warburg effect in mammalian retina.     

G20210A mutation in the prothrombin gene and the risk of recurrent venous thromboembolism

OBJECTIVES: The study was done to determine whether the G20210A mutation in the prothrombin gene increases the risk of recurrent venous thromboembolism (VTE), both alone and in combination with factor V Leiden. BACKGROUND: Several inherited defects of coagulation are associated with increased risk of first VTE, including a recently identified G20210A mutation in the prothrombin gene. However, whether the presence of this mutation confers an increased risk of recurrent venous thromboembolism is controversial. METHODS: A total of 218 men with incident venous thromboembolism were genotyped for the prothrombin mutation and for factor V Leiden and were followed prospectively for recurrent VTE over a follow-up period of 7.3 years. RESULTS: A total of 29 men (13.3%) suffered recurrent VTE. Five of the 14 carriers of the prothrombin mutation developed recurrent VTE (35.7%; incidence rate = 8.70 per 100 person-years), while 24 of 204 individuals who did not carry the prothrombin mutation developed recurrent VTE (11.8%; incidence rate = 1.76 per 100 person-years). Thus, presence of the G20210A mutation was associated with an approximate fivefold increased risk for recurrent VTE (crude relative risk [RR] 4.93; 95% confidence interval [CI] 1.9-12.9; p = 0.001; age-, smoking-, and body mass index-adjusted RR 5.28; 95% CI 2.0-14.0; p = 0.001). In these data, recurrence rates were similar among those with an isolated mutation in the prothrombin gene (18.2%) as compared to those with an isolated factor V Leiden mutation (19.2%). However, all three study participants who carried both mutations (100%) suffered a recurrent event during follow-up. CONCLUSIONS: In a prospective evaluation of 218 men, the presence ofprothrombin mutation was associated with a significantly increased risk of recurrent VTE, particularly among those who co-inherited factor V Leiden.     

Potential cost-effectiveness of C-reactive protein screening followed by targeted statin therapy for the primary prevention of cardiovascular disease among patients without overt hyperlipidemia

BACKGROUND: Evidence suggests that statin therapy reduces the rate of cardiovascular events among patients with low lipid levels but elevated C-reactive protein levels. However, no cost-effectiveness analyses have been performed to assist in determining whether large-scale randomized trials are merited to test this hypothesis. METHODS: We used a Markov model to estimate the benefits, costs, and incremental cost-effectiveness of C-reactive protein screening followed by targeted statin therapy for elevated C-reactive protein levels, compared with dietary counseling alone, for the primary prevention of cardiovascular events among patients with low-density lipoprotein cholesterol levels <149 mg/dL. All costs were in 2000 U.S. dollars. RESULTS: The potential incremental cost-effectiveness ratio for screening followed by statin therapy compared with no screening and no statin therapy was $48,100 per quality-adjusted life-year (QALY) for 58-year-old men and $94,400 per QALY for 58-year-old women. Screening was most cost-effective for 65-year-old men ($42,600 per QALY) and least cost-effective for 35-year-old women ($207,300 per QALY). Our results were most sensitive to the baseline risk of coronary heart disease, the cost of statin therapy, and the efficacy of statin therapy for preventing myocardial infarction in patients with high C-reactive protein levels. If a 58-year-old man who smokes and is hypertensive was considered, screening for C-reactive protein followed by statin therapy would be cost saving if the cost of statin therapy was reduced to $500 per year. If the cost of statin therapy was reduced to $1 per day, the cost-effectiveness of screening would be $4900 per QALY for 58-year-old men and $19,600 per QALY for women of the same age. If the costs associated with elective revascularization (percutaneous coronary intervention or coronary artery bypass surgery) were included in the base case analyses, the incremental cost-effectiveness ratios for screening would be $40,100 per QALY for 58-year-old men and $87,300 per QALY for women. CONCLUSION: A strategy involving C-reactive protein screening to target statin therapy for the primary prevention of cardiovascular disease among middle-aged patients without overt hyperlipidemia could be relatively cost-effective and, in some cases, cost saving.