Carolyn H. McCabe

C-Reactive Protein Levels and Outcomes after Statin Therapy

BACKGROUND Statins lower the levels of low-density lipoprotein (LDL) cholesterol and C-reactive protein (CRP). Whether this latter property affects clinical outcomes is unknown. METHODS We evaluated relationships between the LDL cholesterol and CRP levels achieved after treatment with 80 mg of atorvastatin or 40 mg of pravastatin per day and the risk of recurrent myocardial infarction or death from coronary causes among 3745 patients with acute coronary syndromes. RESULTS Patients in whom statin therapy resulted in LDL cholesterol levels of less than 70 mg per deciliter (1.8 mmol per liter) had lower event rates than those with higher levels (2.7 vs. 4.0 events per 100 person-years, P=0.008). However, a virtually identical difference was observed between those who had CRP levels of less than 2 mg per liter after statin therapy and those who had higher levels (2.8 vs. 3.9 events per 100 person-years, P=0.006), an effect present at all levels of LDL cholesterol achieved. For patients with post-treatment LDL cholesterol levels of more than 70 mg per deciliter, the rates of recurrent events were 4.6 per 100 person-years among those with CRP levels of more than 2 mg per liter and 3.2 events per 100 person-years among those with CRP levels of less than 2 mg per liter; the respective rates among those with LDL cholesterol levels of less than 70 mg per deciliter were 3.1 and 2.4 events per 100 person-years (P<0.001). Although atorvastatin was more likely than pravastatin to result in low levels of LDL cholesterol and CRP, meeting these targets was more important in determining the outcomes than was the specific choice of therapy. Patients who had LDL cholesterol levels of less than 70 mg per deciliter and CRP levels of less than 1 mg per liter after statin therapy had the lowest rate of recurrent events (1.9 per 100 person-years). CONCLUSIONS Patients who have low CRP levels after statin therapy have better clinical outcomes than those with higher CRP levels, regardless of the resultant level of LDL cholesterol. Strategies to lower cardiovascular risk with statins should include monitoring CRP as well as cholesterol.

Cardiac-Specific Troponin I Levels to Predict the Risk of Mortality in Patients with Acute Coronary Syndromes

BACKGROUND In patients with acute coronary syndromes, it is desirable to identify a sensitive serum marker that is closely related to the degree of myocardial damage, provides prognostic information, and can be measured rapidly. We studied the prognostic value of cardiac troponin I levels in patients with unstable angina or non-Q-wave myocardial infarction. METHODS In a multicenter study, blood specimens from 1404 symptomatic patients were analyzed for cardiac troponin I, a serum marker not detected in the blood of healthy persons. The relation between mortality at 42 days and the level of cardiac troponin I in the specimen obtained on enrollment was determined both before and after adjustment for baseline characteristics. RESULTS The mortality rate at 42 days was significantly higher in the 573 patients with cardiac troponin I levels of at least 0.4 ng per milliliter (21 deaths, or 3.7 percent) than in the 831 patients with cardiac troponin I levels below 0.4 ng per milliliter (8 deaths, or 1.0 percent; P < 0.001). There were statistically significant increases in mortality with increasing levels of cardiac troponin I (P < 0.001). Each increase of 1 ng per milliliter in the cardiac troponin I level was associated with a significant increase (P = 0.03) in the risk ratio for death after adjustment for the base-line characteristics that were independently predictive of mortality (ST-segment depression and age > or = 65 years). CONCLUSIONS In patients with acute coronary syndromes, cardiac troponin I levels provide useful prognostic information and permit the early identification of patients with an increased risk of death.

TIMI Frame Count A Quantitative Method of Assessing Coronary Artery Flow

BACKGROUND Although the Thrombolysis in Myocardial Infarction (TIMI) flow grade is valuable and widely used qualitative measure in angiographic trials, it is limited by its subjective and categorical nature. METHODS AND RESULTS In normal patients and patients with acute myocardial infarction (MI) (TIMI 4), the number of cineframes needed for dye to reach standardized distal landmarks was counted to objectively assess an index of coronary blood flow as a continuous variable. The TIMI frame-counting method was reproducible (mean absolute difference between two injections, 4.7 +/- 3.9 frames, n=85). In 78 consecutive normal arteries, the left anterior descending coronary artery (LAD) TIMI frame count (36.2 +/- 2.6 frames) was 1.7 times longer than the mean of the right coronary artery (20.4 +/- 3.0) and circumflex counts (22.2 +/- 4.1, P < .001 for either versus LAD). Therefore, the longer LAD frame counts were corrected by dividing by 1.7 to derive the corrected TIMI frame count (CTFC). The mean CTFC in culprit arteries 90 minutes after thrombolytic administration followed a continuous unimodal distribution (there were not subpopulations of slow and fast flow) with a mean value of 39.2 +/- 20.0 frames, which improved to 31.7 +/- 12.9 frames by 18 to 36 hours (P < .001). No correlation existed between improvements in CTFCs and changes in minimum lumen diameter (r=-.05, P=.59). The mean 90-minute CTFC among nonculprit arteries (25.5 +/- 9.8) was significantly higher (flow was slower) compared with arteries with normal flow in the absence of acute MI (21.0 +/- 3.1, P < .001) but improved to that of normal arteries by 1 day after thrombolysis (21.7 +/- 7.1, P=NS). CONCLUSIONS The CTFC is a simple, reproducible, objective and quantitative index of coronary flow that allows standardization of TIMI flow grades and facilitates comparisons of angiographic end points between trials. Disordered resistance vessel function may account in part for reductions in flow in the early hours after thrombolysis.

TIMI Risk Score for ST-Elevation Myocardial Infarction: A Convenient, Bedside, Clinical Score for Risk Assessment at Presentation An Intravenous nPA for Treatment of Infarcting Myocardium Early II Trial Substudy

BackgroundConsiderable variability in mortality risk exists among patients with ST-elevation myocardial infarction (STEMI). Complex multivariable models identify independent predictors and quantify their relative contribution to mortality risk but are too cumbersome to be readily applied in clinical practice. Methods and ResultsWe developed and evaluated a convenient bedside clinical risk score for predicting 30-day mortality at presentation of fibrinolytic-eligible patients with STEMI. The Thrombolysis in Myocardial Infarction ( TIMI) risk score for STEMI was created as the simple arithmetic sum of independent predictors of mortality weighted according to the adjusted odds ratios from logistic regression analysis in the Intravenous nPA for Treatment of Infarcting Myocardium Early II trial (n=14 114). Mean 30-day mortality was 6.7%. Ten baseline variables, accounting for 97% of the predictive capacity of the multivariate model, constituted the TIMI risk score. The risk score showed a >40-fold graded increase in mortality, with scores ranging from 0 to >8 (P <0.0001); mortality was <1% among patients with a score of 0. The prognostic discriminatory capacity of the TIMI risk score was comparable to the full multivariable model (c statistic 0.779 versus 0.784). The prognostic performance of the risk score was stable over multiple time points (1 to 365 days). External validation in the TIMI 9 trial showed similar prognostic capacity (c statistic 0.746). ConclusionsThe TIMI risk score for STEMI captures the majority of prognostic information offered by a full logistic regression model but is more readily used at the bedside. This risk assessment tool is likely to be clinically useful in the triage and management of fibrinolytic-eligible patients with STEMI.

Enoxaparin Prevents Death and Cardiac Ischemic Events in Unstable Angina/Non–Q-Wave Myocardial Infarction Results of the Thrombolysis In Myocardial Infarction (TIMI) 11B Trial

BACKGROUND Low-molecular-weight heparins are attractive alternatives to unfractionated heparin (UFH) for management of unstable angina/non-Q-wave myocardial infarction (UA/NQMI). METHODS AND RESULTS Patients (n=3910) with UA/NQMI were randomized to intravenous UFH for >/=3 days followed by subcutaneous placebo injections or uninterrupted antithrombin therapy with enoxaparin during both the acute phase (initial 30 mg intravenous bolus followed by injections of 1.0 mg/kg every 12 hours) and outpatient phase (injections every 12 hours of 40 mg for patients weighing <65 kg and 60 mg for those weighing >/=65 kg). The primary end point (death, myocardial infarction, or urgent revascularization) occurred by 8 days in 14.5% of patients in the UFH group and 12.4% of patients in the enoxaparin group (OR 0.83; 95% CI 0.69 to 1.00; P=0. 048) and by 43 days in 19.7% of the UFH group and 17.3% of the enoxaparin group (OR 0.85; 95% CI 0.72 to 1.00; P=0.048). During the first 72 hours and also throughout the entire initial hospitalization, there was no difference in the rate of major hemorrhage in the treatment groups. During the outpatient phase, major hemorrhage occurred in 1.5% of the group treated with placebo and 2.9% of the group treated with enoxaparin (P=0.021). CONCLUSIONS Enoxaparin is superior to UFH for reducing a composite of death and serious cardiac ischemic events during the acute management of UA/NQMI patients without causing a significant increase in the rate of major hemorrhage. No further relative decrease in events occurred with outpatient enoxaparin treatment, but there was an increase in the rate of major hemorrhage.

Prasugrel compared with clopidogrel in patients undergoing percutaneous coronary intervention for ST-elevation myocardial infarction (TRITON-TIMI 38): double-blind, randomised controlled trial

BACKGROUND Mechanical reperfusion with stenting for ST-elevation myocardial infarction (STEMI) is supported by dual antiplatelet treatment with aspirin and clopidogrel. Prasugrel, a potent and rapid-acting thienopyridine, is a potential alternative to clopidogrel. We aimed to assess prasugrel versus clopidogrel in patients undergoing percutaneous coronary intervention (PCI) for STEMI. METHODS We undertook a double-blind, randomised controlled trial in 707 sites in 30 countries. 3534 participants presenting with STEMI were randomly assigned by interactive voice response system either prasugrel (60 mg loading, 10 mg maintenance [n=1769]) or clopidogrel (300 mg loading, 75 mg maintenance [n=1765]) and were unaware of the allocation. The primary endpoint was cardiovascular death, non-fatal myocardial infarction, or non-fatal stroke. Efficacy analyses were by intention to treat. Follow-up was to 15 months, with secondary analyses at 30 days. This trial is registered with ClinicalTrials.gov, number NCT00097591. FINDINGS At 30 days, 115 (6.5%) individuals assigned prasugrel had met the primary endpoint compared with 166 (9.5%) allocated clopidogrel (hazard ratio 0.68 [95% CI 0.54-0.87]; p=0.0017). This effect continued to 15 months (174 [10.0%] vs 216 [12.4%]; 0.79 [0.65-0.97]; p=0.0221). The key secondary endpoint of cardiovascular death, myocardial infarction, or urgent target vessel revascularisation was also significantly reduced with prasugrel at 30 days (0.75 [0.59-0.96]; p=0.0205) and 15 months (0.79 [0.65-0.97]; p=0.0250), as was stent thrombosis. Treatments did not differ with respect to thrombolysis in myocardial infarction (TIMI) major bleeding unrelated to coronary-artery bypass graft (CABG) surgery at 30 days (p=0.3359) and 15 months (p=0.6451). TIMI life-threatening bleeding and TIMI major or minor bleeding were also similar with the two treatments, and only TIMI major bleeding after CABG surgery was significantly increased with prasugrel (p=0.0033). INTERPRETATION In patients with STEMI undergoing PCI, prasugrel is more effective than clopidogrel for prevention of ischaemic events, without an apparent excess in bleeding.

Prasugrel compared with high loading- and maintenance-dose clopidogrel in patients with planned percutaneous coronary intervention: the Prasugrel in Comparison to Clopidogrel for Inhibition of Platelet Activation and Aggregation-Thrombolysis in Myocardial Infarction 44 trial.

Background— The increasing use of higher-than-approved doses of clopidogrel in clinical practice is based in part on the desire for greater levels of inhibition of platelet aggregation (IPA). Prasugrel is a new thienopyridine that is more potent than standard-dose clopidogrel in healthy subjects and patients with stable coronary artery disease. The relative antiplatelet effects of prasugrel versus high-dose clopidogrel in percutaneous coronary intervention patients are unknown. Methods and Results— Prasugrel in Comparison to Clopidogrel for Inhibition of Platelet Activation and Aggregation–Thrombolysis in Myocardial Infarction 44 (PRINCIPLE-TIMI 44) was a randomized, double-blind, 2-phase crossover study of prasugrel compared with high-dose clopidogrel in patients undergoing cardiac catheterization for planned percutaneous coronary intervention. The primary end point of the loading-dose phase (prasugrel 60 mg versus clopidogrel 600 mg) was IPA with 20 &mgr;mol/L ADP at 6 hours. Patients with percutaneous coronary intervention entered the maintenance-dose phase, a 28-day crossover comparison of prasugrel 10 mg/d versus clopidogrel 150 mg/d with a primary end point of IPA after 14 days of either drug. In this study, 201 subjects were randomized. IPA at 6 hours was significantly higher in subjects receiving prasugrel (mean±SD, 74.8±13.0%) compared with clopidogrel (31.8±21.1%; P<0.0001). During the maintenance-dose phase, IPA with 20 &mgr;mol/L ADP was higher in subjects receiving prasugrel (61.3±17.8%) compared with clopidogrel (46.1±21.3%; P<0.0001). Results were consistent across all key secondary end points; significant differences emerged by 30 minutes and persisted across all time points. Conclusions— Among patients undergoing cardiac catheterization with planned percutaneous coronary intervention, loading with 60 mg prasugrel resulted in greater platelet inhibition than a 600-mg clopidogrel loading dose. Maintenance therapy with prasugrel 10 mg/d resulted in a greater antiplatelet effect than 150 mg/d clopidogrel.

Exercise stress testing. Correlations among history of angina, ST-segment response and prevalence of coronary-artery disease in the Coronary Artery Surgery Study (CASS).

Abstract To determine to what extent the diagnostic accuracy of stress testing is influenced by the prevalence of coronary-artery disease, we correlated the description of chest pain, the result of stress testing and the results of coronary arteriography in 1465 men and 580 women from a multicentered clinical trial. The pre-test risk (prevalence of coronary-artery disease) varied from 7 to 87 per cent, depending on sex and classification of chest pain. A positive stress test increased the pre-test risk by only 6 to 20 per cent, whereas a negative test decreased the risk by only 2 to 28 per cent. Although the percentage of false-positive results differed between men and women (12±1 per cent versus 53±3 per cent P < 0.001), this difference was not seen in a subgroup matched for prevalence of coronary-artery disease. We conclude that the ability of stress testing to predict coronary-artery disease is limited in a heterogeneous population in which the prevalence of disease can be estimated through classificat...

C-reactive protein is a potent predictor of mortality independently of and in combination with troponin T in acute coronary syndromes : A TIMI 11A substudy

Abstract Objectives. We evaluated C-reactive protein (CRP) alone and in conjunction with a rapid qualitative assay for cardiac-specific troponin T (cTnT) for predicting 14-day mortality in patients with unstable angina or non-Q wave myocardial infarction (NQMI). Background. Elevated CRP has been found to correlate with higher risk for cardiac events in patients with coronary disease. Methods. At enrollment into the Thrombolysis in Myocardial Infarction (TIMI) 11A trial, a dose-ranging trial of enoxaparin for unstable angina and NQMI, serum was obtained for CRP measurement and rapid cTnT assay. Results. Quantitative CRP and rapid cTnT assays were performed in all patients. CRP was higher among patients who died than in survivors (7.2 vs. 1.3 mg/dl, p = 0.0038). The probability of a positive rapid cTnT assay rose with increasing CRP concentration (p Conclusions. Elevated CRP at presentation in patients with unstable angina or NQMI is correlated with increased 14-day mortality, even in patients with a negative rapid cTnT assay. Quantitative CRP and a rapid cTnT assay provide complementary information for stratifying patients with regard to mortality risk.

Relationship of TIMI Myocardial Perfusion Grade to Mortality After Administration of Thrombolytic Drugs

BACKGROUND Although improved epicardial blood flow (as assessed with either TIMI flow grades or TIMI frame count) has been related to reduced mortality after administration of thrombolytic drugs, the relationship of myocardial perfusion (as assessed on the coronary arteriogram) to mortality has not been examined. METHODS AND RESULTS A new, simple angiographic method, the TIMI myocardial perfusion (TMP) grade, was used to assess the filling and clearance of contrast in the myocardium in 762 patients in the TIMI (Thrombolysis In Myocardial Infarction) 10B trial, and its relationship to mortality was examined. TMP grade 0 was defined as no apparent tissue-level perfusion (no ground-glass appearance of blush or opacification of the myocardium) in the distribution of the culprit artery; TMP grade 1 indicates presence of myocardial blush but no clearance from the microvasculature (blush or a stain was present on the next injection); TMP grade 2 blush clears slowly (blush is strongly persistent and diminishes minimally or not at all during 3 cardiac cycles of the washout phase); and TMP grade 3 indicates that blush begins to clear during washout (blush is minimally persistent after 3 cardiac cycles of washout). There was a mortality gradient across the TMP grades, with mortality lowest in those patients with TMP grade 3 (2.0%), intermediate in TMP grade 2 (4.4%), and highest in TMP grades 0 and 1 (6.0%; 3-way P=0.05). Even among patients with TIMI grade 3 flow in the epicardial artery, the TMP grades allowed further risk stratification of 30-day mortality: 0.73% for TMP grade 3; 2.9% for TMP grade 2; 5.0% for TMP grade 0 or 1 (P=0.03 for TMP grade 3 versus grades 0, 1, and 2; 3-way P=0.066). TMP grade 3 flow was a multivariate correlate of 30-day mortality (OR 0.35, 95% CI 0.12 to 1.02, P=0.054) in a multivariate model that adjusted for the presence of TIMI 3 flow (P=NS), the corrected TIMI frame count (OR 1.02, P=0.06), the presence of an anterior myocardial infarction (OR 2.3, P=0.03), pulse rate on admission (P=NS), female sex (P=NS), and age (OR 1.1, P<0.001). CONCLUSIONS Impaired perfusion of the myocardium on coronary arteriography by use of the TMP grade is related to a higher risk of mortality after administration of thrombolytic drugs that is independent of flow in the epicardial artery. Patients with both normal epicardial flow (TIMI grade 3 flow) and normal tissue level perfusion (TMP grade 3) have an extremely low risk of mortality.