Potential utility of B-type natriuretic peptides in secondary prevention following percutaneous coronary intervention in remote communities of Western Australia.

INTRODUCTION: A third of all acute coronary events that present in the Australian population occur in patients with established coronary heart disease. This study assessed the prognostic value of combined B-type natriuretic peptides (BNP) measurement and quantitative myocardial perfusion scan (MPS) data for cardiac events (CE). MATERIAL AND METHODS: This retrospective cohort study involved 133 patients from rural Western Australia. The cut-off for normality was 6.0 for qualitative summed difference scores (SDS) of MPS and 400 pg/mL for BNP. RESULTS: Patients with no CE had a mean SDS and BNP (1.52 with a 95% CI of 0.34 to 2.69), (175.9 with a 95% CI of 112.7-239.1) that was lower than patients with CE (6.54 with 95% CI 4.18-9.89) (P = 0.0003), (669.1 with 95% CI 543.9-794.3) (P < 0.0001). The sensitivity and specificity of combined testing for predicting CE respectively were 79.6% and 86.3% for SDS, 84.6% and 94.1% for BNP, and 100% and 92.7% for SDS and BNP combined. DISCUSSION AND CONCLUSION: Elevated BNP is marginally superior to MPS in predicting CEs in patients who have previously undergone percutaneous coronary intervention (PCI); however, MPS can identify the region of myocardium most at risk. Routine BNP monitoring in this subgroup may serve as secondary prevention by identifying subclinical disease.

Rural communities are disproportionately affected by preventable coronary heart disease-related deaths and access to cardiac imaging techniques can be infrequent or unavailable.Secondary prevention strategies can reduce hospital readmissions and contribute to improving the management of chronic conditions.This study demonstrated that elevated B-type natriuretic peptides levels were marginally superior to myocardial perfusion scans in predicting cardiac events in patients with prior percutaneous coronary intervention.Monitoring BNP levels in rural patients with prior percutaneous coronary interventions is a relatively non-invasive and inexpensive, and may lead to improved risk estimation, identify the subclinical disease and provoke further investigation as clinically appropriate.

Referral patterns of patients presenting with chest pain at two rural emergency departments in Western Australia.

INTRODUCTION: Coronary heart disease is the largest single cause of death in Australia. In Western Australia invasive diagnostics and therapies for acute coronary syndromes are only provided in the metropolitan hospitals of Perth. Patients in rural hospitals who need invasive cardiac care have to be transferred to Perth. The aim of our research was to determine which patient factors are associated with referral to advanced cardiac care at metropolitan level and how this compares to Australian guidelines for the management of acute coronary syndromes. METHOD: Data was collected from patients presenting with chest pain to the rural emergency department, who were at least 18 years old and had given their consent. Exclusion criteria were chest pain accompanied or precipitated by significant co morbidity and prior enrolment in this study protocol. Socioeconomic and medical information of patients was collected from their medical records. Data was analysed using chi(2) tests, independent sample t-tests and multivariable logistic-regression models (stepwise backwards procedure). RESULTS: The study included 115 rural patients with chest pain with a mean age of 58 years: 66 (57%) men, 12 (10%) indigenous Australians and 38 (33%) transferred patients. Of all transferred patients 19 (50%) had a positive peak troponin-T, 13 (36%) a high peak creatine kinase (CK) and 12 (32%) persistent ST-elevation on their electrocardiogram, compared with 10 (14%), 12 (17%) and 11 (14%) respectively for non-transferred patients. Chi-square-tests showed significant differences between transfer groups in all three essential initial cardiac investigations and known dyslipidaemia. In multivariate analyses the positive peak troponin-T increased odds of transfer (OR6.40; 95% CI 2.55-16.08). This effect increased after adjustment for gender, serum creatinine and known dyslipidaemia (OR27.61; 95% CI 6.41-119.04). When adjusted for the peak troponin-T, neither ECG with persistent ST-elevation nor high peak CK remained significant. Known dyslipidaemia remained significant and serum creatinine became significant. Gender became significant when adjusted for troponin-T, known dyslipidaemia and serum creatinine. CONCLUSIONS: Peak troponin-T is an independent determinant associated with the transfer to advanced care at metropolitan level, but ECG with persistent ST-elevation and peak CK (other essential initial cardiac investigations) are not. Further investigation of the available and provided cardiac care in rural Western Australia is required.