Low-dose computed tomography (LDCT) is a useful diagnostic tool for the identification of patients at high risk for clinically significant aortic stenosis (AS), and the degree of aortic valve calcification (AVC) should be routinely assessed in conjunction with LDCT lung cancer screenings, according to study findings published in the Annals of Internal Medicine.
Although LDCT’s detects pulmonary nodules as an imaging biomarker for lung cancer at significantly reduced radiation levels compared with standard CT, LDCT may also be beneficial for the identification of the early stages of coronary artery disease and chronic obstructive pulmonary disease. Study investigators evaluated LDCT’s usefulness for determining the extent of AVC when performed within a lung cancer screening program, which could correspond with clinically significant AS confirmed by echocardiography.
From 2016 to 2018, a cohort of 6631 volunteers 50 to 80 years of age with a history of smoking for 30 or more pack-years were enrolled in the MOLTEST BIS lung cancer screening program in Poland, it was noted. The degree of calcification was evaluated quantitatively using the Agaston method, and a calcium score (CS) of 900 was arbitrarily selected as a cutoff point to indicate a test result that necessitated further echocardiographic diagnosis. Selection was based on the European Society of Cardiology’s (ESC) Valvular Heart Disease Guidelines.
At least some degree of AVC was identified in 869 of 6631 (13.1%) of patients (women, 35.9%), and 68 (7.8%) of the 869 with ACV, including 17 women (25%), had a CS 900 or greater. Of these, 54 participants provided informed consent to be enrolled in the study, and 49 of the 54 had mild to severe AS. In total, 16 patients were diagnosed with mild AS, 20 with moderate, and 13 (24% of participants with CS 900 or greater) with severe AS. Participants with severe AS were admitted to cardiology for further diagnosis and treatment. The overall percentage of participants diagnosed with mild AS was 0.2%, 0.3% for moderate, and 0.2% for severe. The mean CS for AS-positive patients was 2386 (SD 1735 [range 949-9011]; median 1681), and all patients diagnosed with severe AS had a very high CS (mean 3981.5; SD 1741.84 [range 1788-7415]).
The primary study limitation was the small patient population, which prevented investigators from being able to define an exact cutoff for each AS stage, or estimating correlations between echocardiographic findings and LDCT. Furthermore, the AV CS cutoff of 900 was an arbitrary selection, and investigators indicated that future studies are needed to determine an optimal value.
The study investigators stated, “that LDCT is a useful diagnostic tool for identifying persons at high risk for clinically significant AS and that the degree of AVC should be routinely assessed in all persons undergoing LDCT lung cancer screening.”
Klein-Awerjanow K, Rzyman W, Ostrowski M, Fijalkowska J, Szurowska E, Fijalkowski, M. Aortic stenosis as an additional finding in low-dose computed tomography lung cancer screening: a cross-sectional study Published online June 8, 2021. Ann Intern Med. doi: 10.7326/M20-5507