Exercise testing and myocardial perfusion scintigraphy in primary care patients with chest pain of new onset

Use of exercise tests in primary care: importance for referral decisions and possible bias in the decision process; a prospective observational study

Background

The utility of clinical exercise tests depends on their support of treatment decisions. We sought to assess the utility of exercise tests for the selection of primary-care patients for referral to cardiologic care, and to determine whether referral decisions were biased by gender or socioeconomic status. We also evaluated referral rates and cardiovascular events in patients with positive exercise tests.

Methods

We designed a prospective observational study of 438 men and 427 women from 28 Swedish primary-care clinics who were examined with exercise testing for suspected coronary disease. All participants were followed-up with respect to cardiologist referrals and cardiovascular events (hospitalisation for unstable angina, myocardial infarction, and cardiovascular death) within six months and revascularisation within 250 days. Variables associated with referral were identified by multivariable logistic regression. Socioeconomic status was determined by educational level and employment.

Results

Positive/inconclusive exercise tests and exertional chest pain predicted referral in men and women. Of 865 participants, patients with positive, inconclusive, or negative exercise tests were referred to cardiologists in 67.3%, 26.1%, and 3.5% of cases, respectively. Overall, there was no significant difference in referral rates related to gender or socioeconomic level. Self-employed women were referred more frequently compared to other women (odds ratio (OR) 3.62, 95% confidence interval (CI) 1.19-10.99). Among non-manual employees, women were referred to cardiologic examination less frequently than men (OR 0.40, 95% CI 0.16-1.00; p = 0.049; ORs adjusted for age, exertional chest pain, and exercise test result). In patients with positive exercise tests, the referral rate decreased continuously with age (OR 0.48, 95% CI 0.23-0.97; adjusted for cardiovascular co-morbidity). Cardiovascular events occurred in 22.2% (4/18) of non-referred patients with positive exercise tests; 56% (10/18) of these patients were not considered for cardiologic care, with continuity problems in primary care as one possible contributing cause.

Conclusions

Exercise tests are important for selecting patients for referral to cardiologic care. Interactions related to gender and socioeconomic status affected referral rates. In patients with positive exercise tests, referral rates decreased with age. An increased awareness of possible bias regarding age, gender, and socioeconomic status, which may influence medical decisions, is therefore necessary.

Electronic supplementary material

The online version of this article (doi:10.1186/s12875-014-0182-9) contains supplementary material, which is available to authorized users.

Diagnostic characteristics and prognoses of primary-care patients referred for clinical exercise testing: a prospective observational study

Background

Evaluation of angina symptoms in primary care often includes clinical exercise testing. We sought to identify clinical characteristics that predicted the outcome of exercise testing and to describe the occurrence of cardiovascular events during follow-up.

Methods

This study followed patients referred to exercise testing for suspected coronary disease by general practitioners in the County of Jämtland, Sweden (enrolment, 25 months from February 2010). Patient characteristics were registered by pre-test questionnaire. Exercise tests were performed with a bicycle ergometer, a 12-lead electrocardiogram, and validated scales for scoring angina symptoms. Exercise tests were classified as positive (ST-segment depression >1 mm and chest pain indicative of angina), non-conclusive (ST depression or chest pain), or negative. Odds ratios (ORs) for exercise-test outcome were calculated with a bivariate logistic model adjusted for age, sex, systolic blood pressure, and previous cardiovascular events. Cardiovascular events (unstable angina, myocardial infarctions, decisions on revascularization, cardiovascular death, and recurrent angina in primary care) were recorded within six months. A probability cut-off of 10% was used to detect cardiovascular events in relation to the predicted test outcome.

Results

We enrolled 865 patients (mean age 63.5 years, 50.6% men); 6.4% of patients had a positive test, 75.5% were negative, 16.4% were non-conclusive, and 1.7% were not assessable. Positive or non-conclusive test results were predicted by exertional chest pain (OR 2.46, 95% confidence interval (CI) 1.69-3.59), a pathologic ST-T segment on resting electrocardiogram (OR 2.29, 95% CI 1.44-3.63), angina according to the patient (OR 1.70, 95% CI 1.13-2.55), and medication for dyslipidaemia (OR 1.51, 95% CI 1.02-2.23). During follow-up, cardiovascular events occurred in 8% of all patients and 4% were referred to revascularization. Cardiovascular events occurred in 52.7%, 18.3%, and 2% of patients with positive, non-conclusive, or negative tests, respectively. The model predicted 67/69 patients with a cardiovascular event.

Conclusions

Clinical characteristics can be used to predict exercise test outcome. Primary care patients with a negative exercise test have a very low risk of cardiovascular events, within six months. A predictive model based on clinical characteristics can be used to refine the identification of low-risk patients.

The accuracy of general practitioners' clinical assessment of chest pain patients

OBJECTIVE

To study general practitioners' (GP) assessment of the probability of ischaemic heart disease (IHD) and GP action in daily practice regarding chest pain patients.

METHODS

All chest pain patients aged 20-79 years, attending three primary health-care centres in south-east Sweden and assessed by the GP to have high, low or very low probability of IHD, were included consecutively over a two year period. The "GP action in daily practice" was classed as "active decisions" (investigation or treatment) or "wait and see". "IHD" or "not IHD" was settled according to the results of acute hospital investigation or exercise testing/myocardial perfusion scintigraphy.

RESULTS

516 patients were included, 93 high, 145 low and 278 very low probability cases. The outcome was "IHD" in 47%, 9% and 1% respectively. The sensitivity and specificity of the "GP assessment of the probability of IHD" were 72% and 89%. The sensitivity and specificity of the "GP action in daily practice" were 88% and 72%, respectively. The negative predictive value was 98%.

CONCLUSION

GP assessment, after clinical evaluation, that the probability of IHD was low did not safely rule out IHD. GP action in daily practice however, indicates that general practice is an appropriate level of care for chest pain patients.