We have noticed, in caring for thousands of patients with ascending aortic aneurysm (AscAA), that the “thumb palm test” is often positive (with the thumb crossing beyond the edge of the palm). It is not known how accurate this test may be. We conducted the thumb-palm test in 305 patients undergoing cardiac surgery with intra-operative transesophageal echocardiography (TEE) for a variety of disorders: ascending aneurysm in 59 (19.4%) and non-AscAA disease in 246 (80.6%) (including CABG, valve repair, and descending aortic aneurysm). The TEE provided a precise ascending aortic diameter. The thumb palm test gave us a discrete, binary positive or negative result. We calculated the accuracy (sensitivity and specificity) of the thumb palm test in determining presence or absence of AscAA (defined as ascending aortic diameter > 3.8cm). Maximal ascending aortic diameters ranged from 2.0 to 6.6 cm (mean 3.48). 93 patients (30.6%) were classified as having an AscAA and 212 (69.4%) as not having an AscAA. 10 patients (3.3%) had a positive thumb-palm test and 295 patients (96.7%) did not. Sensitivity of the test (proportion of diseased patients correctly classified) was low (7.5%), but specificity (proportion of non-diseased patients correctly classified) was very high (98.5%). This study supports the utility of the thumb-palm test in evaluation for ascending thoracic aortic aneurysm. That is to say, a positive test implies a substantial likelihood of harboring an ascending aortic aneurysm. A negative test does not exclude an aneurysm. In other words, the majority of aneurysm patients do not manifest a positive thumb-palm sign, but patients who do have a positive sign have a very high likelihood of harboring an ascending aneurysm. We suggest that the thumb-palm test be part of the standard physical examination, especially in patients with suspicion of ascending aortic aneurysm (e.g. those with a positive family history).
Despite the advent of computerized tomographic (CT) scanning over 9,923 Americans die of aortic aneurysm each year (almost certainly an underestimate due to misdiagnosis). We must improve our methods of identifying those at risk. Once identified, the thoracic aortic aneurysm (TAA) patient can be kept safe by exercise restriction, radiographic monitoring and timely surgery). In our experience, the simple, “old-school” physical exam finding of a positive thumb-palm test seemed to have clinical relevance for identifying ascending aortic aneurysm (AscAA). This clinical sign tests the patient’s ability to cross the thumb across and beyond a flat palm. ( Figure 1 ) A test is positive when the patient’s thumb exceeds the width of their flat palm, indicating that the long bones are excessive and that the joints are lax. This sign has been associated with Marfan’s Syndrome and is part of the revised Ghent criteria for its clinical diagnosis. This musculoskeletal finding is indicative of connective tissue disease throughout the body, including in the aorta. However, it is not known how accurate the thumb-palm test may be, in Marfan syndrome or other aortopathies. We examine precisely this issue of accuracy (sensitivity and specificity) in a large number of patients undergoing transesophageal echocardiography (TEE) during cardiac surgery for a variety of disorders.
Methods
We conducted the thumb-palm test in 305 patients undergoing cardiac surgery with TEE. A researcher in the pre-op area of Yale-New Haven Hospital Operating Room performed the thumb palm test on all patients about to undergo cardiac surgery, and this data was analyzed in comparison to the aortic diameters found on TEE to examine the correlation. This study was approved by the Human Investigations Committee of Yale University (1509016419) and verbal consent was obtained from each patient.
The routine intra-operative transesophageal echocardiography in these patients undergoing cardiac surgery provided a precise measure of the diameter of the ascending aorta. We used an ascending aortic diameter of ≥ 3.8cm as diagnostic of ascending aortic aneurysm in both male and female patients (but not necessarily clinically significant).
The thumb palm test gave us a discrete, binary positive or negative result.
With standard statistical analysis, we determined the accuracy (including sensitivity and specificity testing) of the thumb palm test in determining presence or absence of AscAA.
Results
Maximal ascending aortic diameters ranged from 2.0 cm to 6.6 cm (mean 3.48). 93 patients (31%) were classified as having an AscAA and 212 (69%) as not having an AscAA. 10 patients (3.3%) had a positive thumb-palm test and 295 patients (96.7%) did not. These numbers are shown in Table 1 . The sensitivity of the test (proportion of diseased patients correctly classified) was 7.5% and the specificity (proportion of non-diseased patients correctly classified) was 99%. ( Table 1 (A), Figure 2 . ) Positive and negative predictive values are presented in Table 2 (A).
