Stress echo can accurately predict future cardiac events and survival when incorporated into chest pain assessment, a study from a London unit has shown.

Overall, 839 consecutive patients admitted with acute chest pain, non-diagnostic ECG and negative 12-hour troponin were assessed. Patients underwent clinical, ECG and stress echo assessments within 24 hours of admission. The stress echo was performed on a treadmill if the patient could exercise or with dobutamine if not.

There were diagnostic stress echo results for 811 of the 839 patients (96.7%). Results were available quickly and, if negative the patient was discharged, if positive further investigations were carried out.

Patients were followed up for 27±11 months; there were 39 hard events (30 deaths and nine acute myocardial infarctions).

There were 15 hard events in the first year of follow-up. Event rates were 0.5% and 6.6% in the normal and abnormal stress echo groups respectively. Abnormal stress echo HR 4.08 (95% CI:2.15-7.72, P < 0.001) and advancing age HR 1.78 (95% CI: 1.39-2.37, P < 0.001) were the only prognostic variables that predicted hard events in a multivariable analysis.

A normal stress echo carried a 99.7% event-free survival rate for death and a 99.5% event-free rate for all hard events in the first year of follow-up. These event rates increased 15 fold and 13 fold respectively if the stress echo was abnormal.

Chest pain is a common clinical presentation and risk stratification in these patients can be challenging. Acute presentation will more often than not end up in the emergency department or admitted under the on-call medical team. Clinical assessment alone is often inadequate in such patients and serial ECG and 12-hour troponin measurement are used to identify those at highest risk and requiring input from a cardiologist.

The problem area tends to be those with a normal ECG and troponin but whose history is such that a cardiac cause cannot confidently be excluded. The venerable exercise ECG was often used to stratify these patients further despite its proven shortcomings. However stress echo is now more widely available and this study has demonstrated just how useful it can be in these situations.

The authors conclude that stress echo incorporated into a chest pain assessment unit has excellent feasibility, enables rapid assessment and discharge with accurate risk stratification of patients with suspected acute coronary syndrome but non-diagnostic ECG and negative 12-hour troponin.

Dr Peter Savill

• Shah BN, Balaji G, Alhajiri A et al.

The incremental diagnostic and prognostic value of contemporary stress echocardiography in a chest pain unit: mortality and morbidity outcomes from a real-world setting. Circ Cardiovasc Imaging 2012; DOI:10.1161/CIRCIMAGING.112.980797