Monosodium urate (MSU) deposits detected by dual-energy computed tomography (DECT) are common in patients with gout and are associated with higher coronary calcium scores, researchers recently reported in JAMA Cardiology.
Although the risk of cardiovascular disease in gout and hyperuricemia is well established, the underlying mechanisms resulting in cardiovascular damage have not been clearly defined, wrote Sylvia Strobl, M.D., the study’s corresponding author from Medical University Innsbruck in Australia.
This study of 59 gout patients, 47 controls, and 6 fresh cadavers, is believed to be the first to use DECT for direct cardiovascular imaging of MSU deposits.
“There is strong evidence that cardiovascular disease in patients with gout often goes unrecognized and undertreated in primary care…Dual-energy CT imaging without the need of contrast media may provide a relatively simple diagnostic test to reduce the number of unrecognized and undertreated patients with gout at risk for cardiovascular disease,” the authors wrote.
The patients were all older than 35 years and met American Rheumatism Association criteria for gout, with a mean disease duration 3 years and an average of two gout attacks per year. The majority (78%) were men, and the mean age was 59 years.
Cardiovascular MSU deposits were detected in 86.4% of the patients, compared with just 14.9% of the controls (P < .001). Coronary MSU deposits were found in 32.2% versus 4.3%, respectively (P = .003).
The mean coronary calcium score was also significantly higher in the gout patients, 900 Agatston units (AU) versus 263 AU (P = .001). And overall, the coronary calcium score was significantly higher among the 58 individuals who had cardiovascular MSU deposits compared with the 48 who didn’t, 950 AU versus 217 AU (P < .001).
Gout attacks were also more common among the 58 found to have MSU deposits. Of those, 75.9% had one or more gout attacks, compared with just 16.7% of the 48 without MSU deposits (P < .001).
Among the six cadavers - without known gout status - MSU deposits were found by DECT in three, verified by polarizing light microscope.
“Our preliminary findings support the hypothesis of an association between gout and cardiovascular deposition of uric acid and support gout as an independent risk factor for cardiovascular atherosclerosis,” the authors write.
However, they caution, “because most of the MSU-positive studies were found among patients with proven gout, we cannot determine whether MSU deposits are associated with the coronary calcium score independent of the presence of gout.”
The study also demonstrates the feasibility of using DECT - already an established method for detecting MSU deposits in peripheral joints and tendons – for cardiovascular imaging, Klauser and colleagues said.
“The significantly greater extent of cardiovascular MSU deposits in patients with gout compared with controls underscores the potential importance of DECT in a comprehensive cardiovascular examination of patients with gout, which may provide new insights into the cardiovascular disease burden associated with gout,” the authors wrote.
REFERENCE: Klauser AS, Halpern EJ, Strobl S, Gruber J, Feuchtner G, Bellmann-Weiler R, Weiss G, Stofferin H, Jaschke W. "Dual-Energy Computed Tomography Detection of Cardiovascular Monosodium Urate Deposits in Patients With Gout." JAMA Cardiology. 2019 Sep 11. doi: 10.1001/jamacardio.2019.3201. [Epub ahead of print]