Calcium Hides the Clue: Unraveling the Diagnostic Value of Coronary Calcium Scoring in Cardiac Arrest Survivors

<b>Introduction</b>: Coronary artery disease remains one of the most prevalent causes of hospital cardiac arrest (OHCA). Although the benefit of early coronary angiography is well stablished in patients with ST-segment elevation, the benefit and the timing of performing it in other patients remain a matter of debate. This is due to the difficulty of identifying those in which an infarction with non-ST-segment elevation is the cause of the OHCA. Coronary artery calcium (CAC) emerges as a reliable predictor of coronary disease and adverse cardiovascular events, detectable even in non-gated chest computed tomography (CT) scans commonly used in OHCA etiological studies, showcasing potential for streamlined risk assessment and management. <b>Aim</b>: The aim of this study was to evaluate if CAC in non-gated CT scans performed in OHCA survivors could act as a good predictor of coronary artery disease on coronary angiography. <b>Methods</b>: This is a single-center, retrospective study of OHCA survivors without ST-segment elevation at presentation. We selected patients for whom a non-gated chest CT was performed and underwent coronary angiography due to the clinical, electrocardiogram (ECG), or echocardiographic suspicion of acute coronary syndrome. An investigator, blinded to the coronary angiography report, evaluated CAC both quantitively (with Agatston score) and qualitatively (visual assessment: absent, mild, moderate, or severe). <b>Results</b>: A total of 44 consecutive patients were included: 70% male, mean age of 60 ± 13 years old. The mean Agatston score was 396 ± 573 AU (Agatston units). Regarding the qualitative assessment, CAC was classified as mild, moderate, and severe in 11%, 25%, and 20% of patients, respectively. The coronary angiography revealed significant coronary lesions in 15 patients (34%), of which 87% were revascularized (80% underwent PCI and 7% CABG). The quantitative CAC assessment accurately predicted the presence of significant lesions on coronary angiography (AUC = 0.90, 95% CI 0.81-0.99, <i>p</i> < 0.001). The presence of moderate or severe CAC by visual assessment also predicted significant lesions on coronary angiography (OR 2.66, 95% CI 1.87-109.71, <i>p</i> = 0.01). There was also a good and significant correlation between the vessel with severe calcification in the CT scan and the culprit vessel evaluated by coronary angiography. CAC was reported in only 16% of the reviewed CTs, most of them with severe calcification. <b>Conclusion</b>: The assessment of CAC in non-gated chest CT scans proved to be feasible and displayed a robust correlation with the presence, severity, and location of coronary artery disease. Its routine use upfront was shown to be an important complement to CT scan reports, ensuring more precise and personalized OHCA management.