Classification and risk stratification of patients with acute chest pain using a low discriminatory level of cardiac troponin T.

BACKGROUND: Cardiac troponins are the biochemical markers of choice for the evaluation of acute coronary syndromes (ACS). Using the first-generation test, most studies related adverse outcome to > 0.20 or 0.10 microg/l cardiac troponin T (cTnT) levels. With the highly sensitive and specific second- and third-generation assays, cTnT is undetectable in most healthy individuals. HYPOTHESIS: We evaluated whether a lower cTnT level, within 24 h of admission, could indicate an increased risk of future complications. METHODS: During 1998-1999, clinical data were collected in 260 patients with ACS. Cardiac troponin T was measured at arrival, and 4, 8, and 12-24 h thereafter. The maximum cTnT value was then used to assess, over a 15-month follow-up period, the cumulative risk of death or myocardial infarction (MI), as well as rates of events according to quartiles of cTnT values. RESULTS: Patients with < or = 0.03 microg/l cTnT levels had the lowest rate of adverse events and the best Kaplan-Meier event-free survival curve. Increasing cTnT levels were associated with stepwise increases in mortality rates and with a constant 10-fold increase in MI rates during follow-up. CONCLUSIONS: A low threshold cTnT elevation is recommended to assess the risk of ACS. All cTnT elevations > 0.03 microg/l predict a higher risk of MI during follow-up, whereas increasing values predict mortality in relation to the amount of elevation.

Evaluation and risk stratification of acute coronary syndromes using a low cut-off level of cardiac troponin T, combined with CK-MB mass determination.

OBJECTIVES: To study the usefulness of combined cardiac Troponin T (cTnT) and CK-MB mass determinations in risk stratification of acute coronary syndromes. DESIGN AND METHODS: Blood samples for cTnT and CK-MB mass were collected at arrival and 4, 8, and 12-24 later in 301 consecutive patients with recent acute chest pain (ACP). Data were also collected for cardiac events. RESULTS: Combined cardiac mortality/nonfatal myocardial infarction over a period of 15 months was lowest in patients with <0.04 microg/l cTnT and -<5.0 microg/l CK-MB mass intermediate in those with elevated cTnT but normal CK-MB mass and highest when both markers were elevated, in absence of early reperfusion. CONCLUSION: The use of a low cut-off point of cTnT, combined wit CK-MB mass determination, offers a good strategy for risk stratification of ACP patients.

Effect of increasing metabolic syndrome score on atherosclerotic risk profile and coronary artery disease angiographic severity.

The metabolic syndrome (MS) is a frequent cause of coronary artery disease (CAD), and recently the National Cholesterol Education Program Adult Treatment Panel III suggested its diagnosis in the presence of 3 to 5 quantitatively defined markers. Because the consequences of the MS are likely related to the number and diversity of markers, we studied the relation between the number of markers-the MS score-and the degree of abdominal obesity, risk factor profile, and severity of CAD. One thousand one hundred eight subjects of a mostly white population with symptoms of CAD (793 men and 315 women; 58.1 +/- 9.8 years of age) were divided into 6 groups based on their MS scores. A low high-density lipoprotein cholesterol level was the most frequently observed marker, followed by increased blood pressure, triglycerides, waist circumference, and fasting glucose. As the MS score increased so did abdominal obesity, parameters of "nontraditional" dyslipidemia with surrogate markers of dense low-density lipoprotein and high-density lipoprotein particles, blood pressure, fasting glucose, insulin, and the homeostatic model assessment insulin resistance index. Similarly, an increasing MS score was significantly related to more severe coronary angiographic alterations and higher frequencies of unstable angina, myocardial infarction, percutaneous coronary intervention, and coronary artery bypass grafting. Therefore, the MS score provides a clinically useful index of MS severity and the associated atherosclerotic risk factor profile. It also correlates with the angiographic severity of CAD and its clinical complications.

Incidence, coronary risk profile and angiographic characteristics of prediabetic and diabetic patients in a population with ischemic heart disease.

BACKGROUND: Recently, the threshold of fasting blood glucose indicating diabetes mellitus was lowered to 7.00 mmol/L (126 mg/dL) and the term 'impaired fasting glucose' (IFG; fasting blood glucose ranging from 6.11 mmol/L to 6.99 mmol/L or from 110 mg/dL to 126 mg/dL) was introduced to define a prediabetic state. OBJECTIVE: To evaluate the incidence of the above states in a Canadian population with suspected coronary artery disease and to compare their risk profiles and angiographic status to normoglycemic subjects. PATIENTS AND METHODS: Revision of the database of 1108 consecutive patients (793 males and 315 females; mean age 58.1+/-9.8 years) undergoing clinical, biochemical and elective angiographic studies because of suspected coronary artery disease. RESULTS: One third of the patients had either IFG (8.5%), or were diabetics (24.2%). Unlike the 747 normoglycemic patients, both IFG (n=94) and diabetic (n=267) subjects showed an insulin resistance profile, with abdominal obesity, and dislipidemia characterized by high triglycerides in the presence of low high density lipoprotein-cholesterol and high normal or elevated blood pressure. Both prediabetics and diabetics had a significantly higher homeostatic model assessment insulin resistance index than normoglycemics (P<0.0001), the index also being higher for diabetics than for prediabetics (P<0.0001). Coronary atherosclerosis was documented in most patients of the three groups and was significantly more severe in diabetics than in IFG patients (P=0.0359) or normoglycemics (P=0.0069), with no differences between the former two groups. CONCLUSIONS: As expected, the new definitions identify more patients with impaired homeostasis than earlier criteria. IFG patients have similar coronary risk profile as diabetics, suggesting the need for similar coronary precautions.