Computed Tomography and Advanced Cardiac Imaging in Angina and Chest Pain

Results from three presentations on the use of computed tomography and other advanced cardiac imaging in angina and chest pain at the American Heart Association Scientific Sessions 2009.

In “Advanced Cardiac Imaging Uncovers Diagnosis in Patients with Persistent Chest Pain,” Minnisian and colleagues looked at the utility of cardiac magnetic resonance imaging (CMRI) in the diagnosis for women with persistent chest pain (PCP). They looked at CRMI results (including anatomic, functional, adenosine stress perfusionand delayed enhancement imaging) in 113 consecutive patients (average age of 55 years and BMI of 25) who had already undergone evaluation for PCP. The authors reported that 43% of these patients had hypertension, 4% had diabetes, and 3% were smokers. Fully 70% of patients had abnormal imaging results; 57% had microvascular dysfunction, 2% had left ventricular hypertrophy, 1% had hypertrophic obstructive cardiomyopathy, 9% had coronary artery disease, and 2% had “coronary anomaly.” Based on these findings, the authors conclude that “CMRI is usefulfor advanced diagnostic assessment in patients with PCP by detectionof diagnoses with important therapeutic implications.”

In another imaging study involving patients experiencing chest pain, “Chest Pain Patients at Low Risk for Acute Coronary Syndrome: 30 Day Implications of 25—50% Diameter Coronary Stenosis with Cardiac Computed Tomography,” Askew and colleagues examined the “short-term implications of non-obstructive coronary stenosis reported as 25—50% diameter reduction with cardiac CTangiography (CCTA)” in patients presenting with chest pain, hypothesizing that these patients would have “less than a 2% incidence of acute coronary syndrome (ACS) over 30-days.” The authors identified a subgroup of 199 patients who were “prospectively reported to have a 25–50% maximal diameter stenosis at CCTA” from among 1,247 patients with low-risk chest pain who had undergone CCTA. Patients were followed for 30 days to determine the rate of myocardial infarction (MI), coronary revascularization,unstable angina, and cardiovascular death (CVD). These patients “had a mean age of 50.5 years, mosthad a TIMI risk score of 0 (52%) or 1 (38%), 68% had at least two serial cardiac markers performed and 36% had stress testingor cardiac catheterization.” On follow-up, only one patient experienced MI; no patients required revascularization or experienced CVD. This low rate of 30-day acute coronary syndrome in low-risk chest pain patientswith 25–50% stenosis on CCTA led the authors to conclude that “additional testing beyond cardiac biomarkers inthe acute setting to exclude ACS is not routinely indicated.”

In “A Computed Tomography Based Score to Identify Culprit Coronary Lesions among Patients with Acute Chest Pain and Low to Intermediate Likelihood of Acute Coronary Syndrome,” Ferencik and colleagues examined whether “higher remodeling index (RI), spotty calcifications(Ca), and larger plaque area” can be used as variables to create a composite score that can identify “culprit lesions amongpatients with acute chest pain, non-diagnostic ECG and negative initial biomarkers, who have significant coronary disease oncomputed tomography coronary angiography (CT).” In a cohort of 34 patients with acute chestpain, non-diagnostic ECG, and negative initial biomarkers, and in whom CT showed greater than 50% stenosis, researchers evaluated degree and length of stenosis, plaque area and volume, RI, CT attenuation of plaque, and presenceof spotty Ca, comparing the differences between patients with and without acute coronary syndrome (ACS). The data were analyzed to “test the diagnostic value of threescores based on plaque characteristics as well as the TIMI scorewith the outcome of ACS.” TIMI score was not predictive of ACS; of the three scores, the one that incorporated RI, spotty Ca, plaque area, and stenosis length and volume had the highest diagnostic value. The authors conclude that, in patients with acute chest pain, inconclusive initial evaluation, and CT-detected stenosis, “a lesion score including RI, spottyCa, plaque area, low HU plaque volume, and stenosis length hasgood diagnostic value to prospectively identify culprit lesionsand ACS.”