Critical Coronary Artery Disease in a Patient with a Normal Nuclear Stress Test
D. A. Neville Mascarenhas
An 88-year-old woman presented to our office with complaints of chest pain. Investigations included a normal nuclear stress test. Three weeks later, she returned to our office with complaints of a persisting chest pain. A repeat electrocardiogram (ECG) showed new hyperacute T waves in leads 2, 3, and aVF. The patient underwent cardiac catheterization which revealed 95% stenosis in the distal portion of the left anterior descending coronary artery. A stent was placed, after which 0% stenosis was observed. Following stent placement, the patient’s ECG returned to baseline and she has had no recurring symptoms to date.
An 88-year-old woman with a medical history of hypertension, dyslipidemia, and hypothyroidism andprior percutaneous transluminal coronary angioplasty (PTCA) of her left anterior descending (LAD) coronary artery, presented to our office with complaints of a substernal, intermittent,aching-type chest pain of a one-day duration. Work-up also included a normal nuclear stress test with normal left ventricular function and no changes from a prior study done three years earlier. Three weeks later, she presented again with similar complaints of chest pain that was now waking her up from sleep. An ECG done now showed sinus rhythm with T wave inversions (leads aVR, aVL, and V1-V2) and hyperacute T waves in leads 2, 3, and aVF (Figure 1). In view of her chest pain associated with ECG changes, we recommended cardiac catheterization to be done.
A cardiac catheterization was performed which showed isolated LAD artery disease (95% stenosis of the distal segment). A bare metal stent was placed, after which repeat angiography showed 0% stenosis (Figures 2 and 3).Three days following stent placement, a repeat ECG showed resolution of T wave abnormalities. To date, the patient has had no recurring cardiac symptoms.
Current guidelines from the American College of Cardiology (ACC) recommend stress testing in patients suspected to have stable ischemic heart disease, with exercise ECG being the preferred initial modality for patients with low to intermediate pretest probability (PTP) and stress myocardial perfusion imaging (MPI) or echocardiography being preferred for high PTP.
A commonly utilized type of MPI is pharmacologic myocardial perfusion scintigraphy (P-MPS) which is typically performed using either adenosine (or related vasodilators) or dobutamine. Adenosine MPS has a sensitivity of 75-96% and specificity of 71-100% for detection of >50% coronary stenosis, while dobutamine MPS has a sensitivity of 64-97% and specificity of 64-100% for detecting these lesions.
ACC guidelines recommend optimization of medical therapy (including statin therapy, glycemic and blood pressure control, weight loss, exercise, and diet modification) rather than cardiac catheterization in patients with negative MPI. However, as this case report demonstrates, clinical judgement is important in the setting of evolving symptoms or ECG changes.
Hyperacute T waves on ECG, as seen in this case, have been described as an early sign of cardiac ischemia and can appear as soon as 2 minutes following disruption of coronary blood flow in studies involving coronary artery ligation. The hyperacute T waves caused by ischemia will typically be present before infarction occurs, with other signs such as troponin leak and ST-elevation developing later.
While stress testing plays an important role in the diagnosis of ischemic heart disease, it is important to remember that, like all diagnostic testing, it has limitations and the potential for inaccurate results. We present this case to emphasize the importance of assessment of the whole clinical picture, rather than relying on a single test, to make decisions involving patient care.
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