Reminder to quote myocardial infarction and emergency angioplasty when consenting for dobutamine stress echo – a rare case

Abstract

Background Dobutamine stress echocardiogram (DSE) is a widely used diagnostic tool for patients with new onset chest pain in whom angina cannot be ruled out by clinical assessment alone. It is also used for risk stratification to guide coronary revascularization for patients with known ischaemic heart disease. It is a low-risk procedure and myocardial infarction is quoted as a rare complication of the test. Case Summary A 38-year-old gentleman presented to chest pain clinic for symptoms of atypical chest pain. He has been getting a central throbbing discomfort with no radiation. His pain was normally exacerbated on exertion lasting for 20 minutes and eased with rest; associated with feeling hot and sweatiness. Similar symptoms could also occur at rest with some episodes lasting for a few hours; associated with nausea as well as pins and needles. In view of these atypical symptoms, he had Spider flash monitor, echocardiography and dobutamine stress echocardiography for further assessment. The Spiderflash did not capture arrhythmias and echocardiogram showed normal left ventricular systolic function. He attended DSE which showed no evidence of regional wall motion abnormality nor ischaemic changes at any stages of the test including peak stress. He later developed vasovagal response to high dose of Dobutamine (40mcg/Kg/min) with blood pressure dropping to 58/39 mmHg. He had chest discomfort at this stage but there was no regional wall motion abnormality or ECG changes. This all resolved after stopping Dobutamine and systolic blood pressure returned to >90mmHg. As per practice, the patient was kept outside to monitor for delayed complications. A few minutes later, he experienced severe chest discomfort, sweatiness, and clamminess. He was promptly assessed, and subsequent echo showed new hypokinesia at inferoseptum and inferior walls. 12 lead ECG showed inferolateral ST elevation with new LBBB (Figure 1). He was then transferred to the primary PCI centre. Coronary angiogram revealed complete occlusion of distal segment of the right coronary artery (Figure 2) which was successfully treated with angioplasty and drug eluting stent. Recovery was uneventful and he was discharged with dual antiplatelets and secondary prevention therapies. Conclusion and Discussion In our case, the clinical timeline and imaging features suggest that initial DSE was normal, however, the test may have contributed to endothelial shear stress and plaque rupture leading to ST elevation acute myocardial infarction. Although the occurrence of acute coronary syndrome after dobutamine administration during stress testing may be coincidental, clinicians should be aware of the possible rare complications and should educate patients when ordering stress tests. Such risk should be clearly mentioned when consenting patients for DSE.