Association of uric acid with mortality in patients with stable coronary artery disease

A novel metabolic balance model for describing the metabolic disruption of and interactions between cardiovascular-related markers during acute myocardial infarction

OBJECTIVE

After acute myocardial infarction (AMI), an integral evaluation of risk using multimarker approach and the understanding of the pathophysiological processes involved have recently received much attention. This study aimed to develop a model to integrally evaluate the metabolic disruption of cardiovascular-related markers and unveil their interactions after AMI.

METHODS

AMI was induced in rats by coronary artery ligation. Several cardiovascular-related markers in plasma and the heart were determined during AMI. A metabolic balance model was developed using matrix equations to assess the metabolic disturbance of, and interactions between, these markers.

RESULTS

Metabolic balance maps intuitively depicted the metabolic disruption of cardiovascular-related markers after AMI. The deviation and magnitude of the disruption were quantitatively and integrally described by φ and k (the dynamic parameter of metabolic balance disruption), respectively. The metabolic balance was disturbed in both the circulatory system and the heart post-AMI. All of the measured markers appeared to be interactional. Among these markers, kidney function and dimethylarginine dimethylaminohydrolase (DDAH) activity in the heart showed a potent effect on the other markers, whereas asymmetric dimethylarginine (ADMA) levels in plasma and adenosine triphosphate (ATP) contents in the heart were susceptible to the effects of the other markers.

CONCLUSION

A metabolic balance model was developed to integrally evaluate the disruption of cardiovascular-related markers after AMI, which proposes a new method for evaluating the disease state post-AMI using a multimarker approach. The unveiled interactions between these cardiovascular-related markers are helpful in understanding the pathophysiological processes.

Uric acid and prognosis in angiography-proven coronary artery disease

BACKGROUND

The optimal uric acid (UA) level associated with the lowest mortality and the strength of association between UA and mortality in various subgroups of patients with coronary artery disease (CAD) are unknown.

MATERIALS AND METHODS

This study included 13 273 patients with angiographic confirmation of CAD and UA measurements available. The primary outcome analysis was 1-year mortality.

RESULTS

Based on the receiver operating characteristic curve analysis, the best cut-off of UA for mortality prediction was 7·11 mg/dL. Using this cut-off, patients were divided into two groups: the group with UA ≤ 7·11 mg/dL (n = 9075) and the group with UA > 7·11 mg/dL (n = 4198). Cardiac mortality was 6·3% (256 deaths) in patients with UA > 7·11 mg/dL and 2·3% (201 deaths) in patients with UA ≤ 7·11 mg/dL [hazard ratio (HR) = 2·82, 95% confidence interval (CI) 2·36-3·36; P < 0·001]. After adjustment for cardiovascular risk factors, UA remained an independent correlate of cardiac mortality (HR = 1·20, 95% CI 1·08-1·34; P = 0·001, for each standard deviation increase in the logarithmic scale of UA). The relationship between cardiac or all-cause mortality and UA showed a J-shaped pattern with lowest mortality in patients with UA between 5·17 and 6·76 mg/dL. UA predicted mortality across all subgroups of patients, with strongest association in women and patients without arterial hypertension.

CONCLUSIONS

UA predicted an increased risk of cardiac mortality across all subgroups of patients with CAD. The association between UA and cardiac or all-cause mortality had a 'J-shaped' pattern with lowest risk of death in patients with UA levels between 5·17 and < 6·76 mg/dL.

Prognostic value of uric acid in patients with Type 2 diabetes mellitus and coronary artery disease

Studies investigating the prognostic role of UA (uric acid) in patients with Type 2 diabetes mellitus have given conflicting findings. We undertook the present study to assess the association between UA and outcome in patients with Type 2 diabetes mellitus and CAD (coronary artery disease). The study included 3705 patients with diabetes mellitus and angiography-proven CAD. UA was measured before coronary angiography. The primary outcome was 1-year all-cause mortality. The UA concentration [median (25th–75th quartiles)] was 6.44 mg/dl (5.40–7.70 mg/dl). There were 264 deaths (7.1%) during follow-up: 45 deaths in patients of the first UA quartile, 43 deaths in patients of the second UA quartile, 51 deaths in patients of the third UA quartile and 125 deaths in patients of the fourth UA quartile {Kaplan–Meier estimates of mortality, 5.1, 4.8, 5.6 and 14.0% respectively; unadjusted HR (hazard ratio), 2.81 [95% CI (confidence interval), 2.21–3.58]; P<0.001 for fourth quartile compared with first–third quartiles combined}. In the multivariable analysis, UA predicted all-cause mortality with an adjusted HR of 1.29 (95% CI, 1.12–1.48; P<0.001), for each S.D. increase in the logarithmic scale of UA level. The inclusion of UA in the multivariable model alongside known cardiovascular risk factors and other relevant variables increased the discriminatory power of the model regarding prediction of all-cause mortality [absolute and relative IDI (integrated discrimination improvement) 0.034 and 20.5% respectively; P<0.001]. In conclusion, in patients with Type 2 diabetes mellitus and confirmed CAD, elevated levels of UA predict mortality independently of known cardiovascular risk factors.