Coronary calcium seen on lung CTs could signal heart risk in pulmonary embolism patients

Coronary artery calcification is often visible on the CT scans used to diagnose acute pulmonary embolism, but radiologists frequently leave it out of their reports. A narrative review argues that this overlooked finding may have two different meanings: it could help refine prognosis after a confirmed embolic event, and it also provides a no-extra-cost, no-added-radiation glimpse of unrecognised coronary atherosclerosis. Published in the Egyptian Journal of Radiology and Nuclear Medicine, the review gathers the available evidence on calcium seen during routine CT pulmonary angiography and says the two uses should be kept strictly separate.

Acute pulmonary embolism is the third most common acute cardiovascular syndrome, with an estimated age-adjusted incidence of 60 to 120 per 100,000 person-years and a 30-day mortality of 2 to 10 percent despite advances in anticoagulation and risk stratification. Precise prognosis at diagnosis helps determine whether patients can be managed as outpatients, need close monitoring, or should be considered for reperfusion therapy. Current practice combines clinical scores such as the Pulmonary Embolism Severity Index, cardiac biomarkers including troponin and B-type natriuretic peptide, and imaging markers of right ventricular strain taken from the same CT scan.

The review says the difficulty is that acute right ventricular findings mostly reflect the haemodynamic impact of the embolus. They may not reflect the patient’s underlying cardiovascular reserve. Two people with similar right ventricular dilation can differ greatly in coronary artery disease, heart failure, or chronic lung disease. Coronary artery calcification, which marks coronary atherosclerotic plaque burden, is a logical candidate for capturing that hidden vulnerability, and it is already visible within the field of view of every pulmonary embolism CT without any additional scan or radiation exposure.

The evidence, however, is mixed. In one cohort of 479 inpatients with confirmed acute pulmonary embolism who also underwent echocardiography, any visible coronary calcification was linked to 30-day pulmonary embolism-related mortality in unadjusted analysis, with an odds ratio of 3.5. After adjustment for age and sex, the association weakened, and in the fully adjusted model that included right ventricular strain, peak troponin T, and cardiovascular risk factors, it was no longer statistically significant, with an odds ratio of 3.4 and a confidence interval crossing one. A similar pattern appeared for all-cause mortality: the unadjusted odds ratio of 3.1 dropped to a non-significant 2.6 after full adjustment.

Other studies used very different approaches. One group of 118 patients scored the four main coronary arteries from 0 to 3 and summed them to a total score from 0 to 12, finding that a data-derived threshold above 5.5 was independently associated with 30-day pulmonary embolism-related mortality. A retrospective review of 245 confirmed cases used the Weston score and found that a score of 6 or higher remained associated with six-month all-cause mortality in the overall multivariable analysis. But 20 percent of that cohort had active cancer, and once those patients were removed the calcium score no longer had an independent association, leaving only the Glasgow Prognostic Score significant. A fourth study of 400 consecutive patients found that any calcification was associated with three-year all-cause mortality in univariable analysis, and that the total score stayed independently associated with all-cause mortality after age adjustment, but not with pulmonary embolism-related mortality.

The review warns that these studies cannot simply be combined. They used different definitions of calcium, involved different patient populations, and adjusted for confounders to different degrees. Some reported only unadjusted estimates, and thresholds derived from the data may fit small samples too closely. No large prospective study has yet shown that adding coronary calcification to a validated acute pulmonary embolism risk model improves discrimination, calibration, reclassification, or clinical decisions beyond established tools such as the severity index, the right ventricular to left ventricular diameter ratio, troponin, and B-type natriuretic peptide.

There is also a technical limitation. Dedicated quantitative calcium scoring is usually done on non-contrast, ECG-gated cardiac CT with the Agatston method. Routine pulmonary embolism CT is contrast-enhanced and non-gated, and intravascular iodine plus cardiac motion can hide or imitate small high-attenuation foci. The standard 130-HU Agatston threshold cannot simply be transferred. In a paired validation study, visual assessment on contrast-enhanced chest CT achieved 83 percent sensitivity and 100 percent specificity for detecting calcification compared with dedicated scoring CT, but every false-negative case had a low calcium burden below an Agatston score of 30. A report saying no calcification was seen should therefore not be treated as the same as a definitive Agatston score of zero.

Researchers have explored higher attenuation thresholds on contrast-enhanced coronary CT angiography, including thresholds above 351 and 600 HU, but performance varied with reconstruction method and clinically meaningful reclassification of calcium categories still occurred. Even the better-performing method was not equivalent to standard non-contrast scoring, and such thresholds reduce sensitivity for small or lower-density calcifications. The review says the most practical current approach is a whole-patient visual ordinal grade of none, mild, moderate, or severe, in line with existing guidance for non-gated thoracic CT, using the morphology and location along the expected coronary course rather than a fixed HU cutoff.

The opportunistic screening message may be more reliable than the prognostic one. In a cohort of 414 patients undergoing CT pulmonary angiography for suspected pulmonary embolism, only 18.1 percent of whom actually had the condition, moderate-to-severe visual calcification independently predicted a composite of cardiovascular death, myocardial infarction, or coronary revascularisation, with a hazard ratio of 5.30, and all-cause mortality, with a hazard ratio of 1.52, after adjustment for age, sex, cardiovascular risk factors, and pulmonary embolism diagnosis. Another analysis of 100 patients scanned for non-cardiac chest pain reported major adverse cardiac events in 46.8 percent of those with calcification versus 3.8 percent without, although that unadjusted conference-abstract analysis was kept only as contextual evidence.

The review also points to underreporting as a broader problem. One study found that coronary calcification was left out of the original CT report in 45 percent of patients in whom it was later identified. Because the scan has already been obtained for a necessary clinical reason, clearly visible calcification can reveal coronary atherosclerosis without more imaging or radiation, and the report should help prompt assessment of modifiable cardiovascular risk factors rather than automatically leading to ischaemia testing in asymptomatic patients. Future research, the authors say, should separate confirmed from suspected pulmonary embolism populations, define calcium exposure in advance, report acquisition and reconstruction parameters and reader reproducibility, and test added value against established risk models before coronary calcification is recommended for acute pulmonary embolism triage.

Subject of Research: Coronary artery calcification detected on CT pulmonary angiography as a prognostic marker in acute pulmonary embolism

Article Title: CTPA-detected coronary artery calcification as a prognostic marker in acute pulmonary embolism: a narrative review

Article References: Naidu, J., Baskaradoss, V., Basit, A., & Shawki, M. (2026). CTPA-detected coronary artery calcification as a prognostic marker in acute pulmonary embolism: a narrative review. Egyptian Journal of Radiology and Nuclear Medicine, 57(1), Article 213. https://doi.org/10.1186/s43055-026-01881-2

Image Credits: AI Generated

Keywords: pulmonary embolism, coronary artery calcification, CT pulmonary angiography, risk stratification, opportunistic screening, coronary atherosclerosis, Agatston score, right ventricular strain, prognostic markers, cardiovascular risk assessment, narrative review, radiology

Cite Scienmag News

Ophelia Keating. (October 30, 2026). Coronary calcium on lung scans may flag heart risk in pulmonary embolism patients. Scienmag. https://scienmag.com/coronary-calcium-on-lung-scans-may-flag-heart-risk-in-pulmonary-embolism-patients/

Ophelia Keating. "Coronary calcium on lung scans may flag heart risk in pulmonary embolism patients." Scienmag, 30 October 2026, https://scienmag.com/coronary-calcium-on-lung-scans-may-flag-heart-risk-in-pulmonary-embolism-patients/. Accessed 30 October 2026.