Accuracy of the "Thumb-Palm Test" for Detection of Ascending Aortic Aneurysm.

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).

Efficacy of a topical formulation of selamectin plus sarolaner against induced infestations of Amblyomma americanum on cats and prevention of Cytauxzoon felis transmission.

Cytauxzoonosis, caused by infection with Cytauxzoon felis, is the most severe tick-borne disease of cats. The purpose of our study was to determine the efficacy of selamectin (6.0 mg/kg) plus sarolaner (1.0 mg/kg) formulated in combination (Revolution® Plus / Stronghold® Plus, Zoetis) applied topically once a month on cats for three months against induced infestations of Amblyomma americanum adults and to evaluate the effectiveness of the product in preventing the transmission of C. felis. This study was conducted in two phases. Sixteen cats were dosed with selamectin/sarolaner or a placebo (vehicle control) on Days 0, 28, and 56. In phase 1, each cat was infested with 50 (±5) unfed adult A. americanum on Day 4 and tick counts were conducted on Day 6 (48 h post infestation) and Day 7 (72 h post infestation) to evaluate acaricidal efficacy. In phase 2, to confirm acaricidal efficacy and evaluate prevention of C. felis transmission, each cat was infested on Day 60 with 50 (±5) adult A. americanum acquisition fed as nymphs on two C. felis-infected donor cats. Tick counts were conducted on Day 62 (48 h post infestation) and Day 63 (72 h post infestation). Blood samples were collected on Days -9, 60, 70, 76, and 90 and tested for infection with C. felis. Placebo cats were adequately infested on all count days, with least squares (geometric) mean live tick counts ranging from 34.0 (28.8) to 46.1 (46.0). Treatment reduced the least squares (geometric) mean counts compared to placebo by 27.1 (32.1)% and 90.4 (96.8)% on Days 6 and 7, respectively. The corresponding percent reductions were 56.4 (60.6)% and 94.7 (97.3)% on Days 62 and 63, respectively. Least squares mean counts were significantly lower in the treated group compared with the placebo group on all count days (P ≤ 0.0286). All cats were negative for C. felis by PCR prior to study start. In phase 2, seven cats in the control group and no cats in the selamectin/sarolaner group became infected with C. felis (P = 0.0017). Topical treatment with selamectin/sarolaner was >90% effective in reducing A. americanum tick counts 72 h after infestation and prevented the transmission of C. felis from infected ticks following the third of three monthly treatments. Revolution® Plus / Stronghold® Plus offers an option for the control of A. americanum infestations on cats and for preventing the transmission of C. felis to cats.