Exercise testing to predict outcome in patients with angina

Study of Ischemia Modified Albumin as a Biomarker in Acute Ischaemic Stroke

Background and Purpose

Stroke is one of the leading causes of mortality and long-term disability. Prompt diagnosis and treatment of stroke are crucial for a better outcome. A blood test, which serves as a biomarker in rural areas will help in immediately transferring patients to a hospital for thrombolytic therapy. The aim of the present study was to examine the role of ischemia modified albumin (IMA) as a screening biomarker in acute ischaemic stroke.

Materials and Methods

Serum samples were collected from 50 patients with acute ischaemic stroke within one, 24, 48, 72 and 144 h of time of admission for IMA. We compared patients' 1st-hour value with age- and sex-matched controls by independent sample t test. p value < 0.05 was considered significant.

Results

The serum IMA levels of patients 1st hour (108 ± 8.9) were significantly higher than those of the controls (79 ± 6.3) p < 0.05. The IMA levels showed a steady decline at 1 h (108 ± 8.9), 24 h (94 ± 4.2), 48 h (82 ± 6.1), 72 h (77 ± 5.6) and 144 h (76 ± 3.8) of admission in patients.

Conclusion

We observed that serum IMA was significantly higher in stroke patients as compared to controls. IMA was elevated in the acute phase of stroke and had a gradual graded decline over 1 week. We concluded that IMA may be a sensitive and rapid biomarker for screening of early ischaemic stroke in rural settings.

Developing and assessing cardiovascular biomarkers

Atherosclerosis is a slow process that over time can lead to fatal events. Early identification and prediction of future risk can allow for preventive strategies to be instituted. There is an increasing interest in utilizing novel biomarkers in cardiovascular disease screening and management. These novel biomarkers may help in cardiovascular disease risk assessment and treatment monitoring, and some may be treatment targets. To be useful for risk prediction, novel biomarkers need to show a significant association with cardiovascular disease events and bring additional value in risk stratification when added to known risk prediction models. Biomarkers used for treatment monitoring need to show that they can serve as good surrogates of cardiovascular disease status. In this article, we present 3 biomarkers that are currently approved by the U.S. Food and Drug Administration for use in cardiovascular disease management and risk assessment: C-reactive protein, lipoprotein-associated phospholipase A2, and myeloperoxidase. Other new biomarkers have also been shown recently to help in cardiovascular disease risk prediction and management. In this article, we will review 2 of these new biomarkers: cardiac troponin T measured by a highly sensitive assay and brain natriuretic peptide.

Incremental prognostic value of the exercise electrocardiogram in the initial assessment of patients with suspected angina: cohort study

OBJECTIVE

To determine whether resting and exercise electrocardiograms (ECGs) provide prognostic value that is incremental to that obtained from the clinical history in ambulatory patients with suspected angina attending chest pain clinics.

DESIGN

Multicentre cohort study.

SETTING

Rapid access chest pain clinics of six hospitals in England.

PARTICIPANTS

8176 consecutive patients with suspected angina and no previous diagnosis of coronary artery disease, all of whom had a resting ECG recorded. 4848 patients with a summary exercise ECG result recorded (positive, negative, equivocal for ischaemia) comprised the summary ECG subset of whom 1422 with more detailed exercise ECG data recorded comprised the detailed ECG subset.

MAIN OUTCOME MEASURE

Composite of death due to coronary heart disease or non-fatal acute coronary syndrome during median follow-up of 2.46 years.

RESULTS

Receiver operating characteristics curves for the basic clinical assessment model alone and with the results of resting ECGs were superimposed with little difference in the C statistic. With the exercise ECGs the C statistic in the summary ECG subset increased from 0.70 (95% confidence interval 0.68 to 0.73) to 0.74 (0.71 to 0.76) and in the detailed ECG subset from 0.74 (0.70 to 0.79) to 0.78 (0.74 to 0.82). However, risk stratified cumulative probabilities of the primary end point at one year and six years for all three prognostic indices (clinical assessment only; clinical assessment plus resting ECG; clinical assessment plus resting ECG plus exercise ECG) showed only small differences at all time points and at all levels of risk.

CONCLUSION

In ambulatory patients with suspected angina, basic clinical assessment encompasses nearly all the prognostic value of resting ECGs and most of the prognostic value of exercise ECGs. The limited incremental value of these widely applied tests emphasises the need for more effective methods of risk stratification in this group of patients.

Exercise electrocardiogram testing and prognosis. Novel markers and predictive instruments

Ample evidence now exists supporting the use of the exercise test primarily for prognostic, as opposed to diagnostic, purposes. Although limitations must be recognized, the Duke exercise treadmill score, the chronotropic response to exercise, and heart rate recovery appear to function as powerful and independent predictors of risk. With the possible exception of exercise-induced ischemia, as manifested by the ST-segment and angina components of the Duke exercise treadmill score, exercise predictors of risk are not clearly modifiable. Nonetheless, they are clinically quite useful since they may well identify patients who are or are not likely to gain benefit from further testing and aggressive therapies. How so? The "plain old" exercise treadmill test makes it possible to easily, safely, and inexpensively identify a large group of patients who are at low risk for death or major cardiac events. For this reason alone, the predictive instruments described in this article should be routinely incorporated into clinical practice. It makes no sense to perform expensive and potentially risky diagnostic tests, prescribe polypharmacy, or institute invasive therapeutic procedures in patients who are already at low risk. As an example, Weiner and colleagues found that coronary bypass grafting only benefited CASS registry patients who had a high-risk exercise test result. Future research will be needed to further refine risk stratification with the exercise test, and determine how best to use adjunctive imaging studies and to reduce risk among patients with prognostically important findings.

Diagnostic testing

The results of cardiac tests must always be interpreted through the lens of pretest probabilities created by the history and the physical examination. Tests should be chosen with a clear diagnostic and prognostic purpose in mind. A clear understanding of the relationship between the history and physical examination and more technologic diagnostic testing improves the primary care physician's ability to evaluate potential cardiac disease in an efficient and cost-effective manner.