PURPOSE: Patients with acute pulmonary embolism (APE) who are hemodynamically stable with evidence of right heart strain on trans-thoracic echocardiogram (TTE) are at an increased risk for cardiovascular collapse and death. Although TTE is not always readily available, CT angiogram has become the test of choice for diagnosing APE. We sought to determine whether cardiac and vascular measurements made on CT angiogram by non-radiologists could obviate the need for TTE.
METHODS: Patients diagnosed with APE by CT angiogram were enrolled prospectively. All patients had a TTE performed in addition to a standard work-up. Three separate physicians (a medicine resident, pulmonary fellow, and pulmonary staff) measured the diameter of the superior vena cava (SVC), width of the azygous, and ratio of the right to left ventricular diameter (RV/LV ratio). Septal morphology was recorded, with bowing to the right considered normal and straightening or bowing to the left abnormal. CT measurements were compared with TTE values.
RESULTS: 28 patients, with an average age of 50, were enrolled. Among the three pulmonary physicians, intra-rater agreement on RV/LV ratio > 1 was good (k=0.61, p=0.002) while agreement on septal bowing was poor. The mean RV/LV ratios among the three raters were 0.95, 0.99, and 1.69 when RV function by TTE was graded as normal, mildly reduced, or moderately reduced respectively (p<0.001); and 0.94, 1.04, 2.02, and 1.52 when RV dilatation by TTE was graded as normal, mild, moderate, or severe (p<0.001). Neither SVC diameter nor azygous width reached statistical significance when compared with TTE measurement of RV function or dilatation.
CONCLUSION: Physicians without specific CT training are able to grade RV/LV ratio with good intra-rater agreement and the ability to predict TTE measurements.
CLINICAL IMPLICATIONS: Larger patient cohorts should be studied with CT measurements compared to clinical outcomes.
DISCLOSURE: Anita Shah, No Financial Disclosure Information; No Product/Research Disclosure Information