Does preoperative CT thorax aid in cardiac surgery?

Routine use of preoperative screening computed tomography (CT) of the thorax in patients undergoing cardiac surgery does not appear effective in reducing mortality or stroke rates, reports a study.

“While modern technology allows markedly reduced radiation dose for CT thorax, these results do not support routine CT thorax before primary cardiac surgery,” the investigators said. “It may be considered for selected elderly patients with higher inherent stroke risk.”

A total of 392 patients who had cardiac surgery from January 2013 to October 2017 were included in this study conducted by investigators from the National University Heart Centre, National University Health System, Singapore. Patients who underwent screening CT thorax prior to cardiac surgery (CT group) were compared to those who did not (no CT group).

Finally, the investigators performed multivariate subgroup analyses to explore significant associations with postoperative outcomes.

Of the patients, 156 underwent preoperative screening CT thorax. Individuals in the CT group tended to be older (63.9 vs 59.0 years; p=0.001), have fewer recent myocardial infarctions preoperatively (41 percent vs 56.4 percent; p=0.003), and have better ejection fraction (>30 percent; p=0.02) than those in the no CT group. [Singapore Med J 2026;67:90-94]

Some of the patients (4.3 percent) had a change in operative strategy, and a few (4.9 percent) suffered stroke after the procedure.

The presence of CT aortic calcifications significantly correlated with change in operative strategy (p=0.016), but not with stroke (p=0.33). Among those who underwent CT thorax, age was independently associated with change in operative strategy (p=0.02). In multivariate analysis adjusted for age, only palpable plaque showed a significant relationship with change in operative strategy (p<.001).

Moreover, patients with CT emphysema features did not develop pneumonia.

“[R]outine preoperative screening CT thorax may assist in preoperative surgical planning, as concluded in the best evidence study by Merlo [and colleagues],” the investigators said. “However, it does not necessarily contribute to decreased mortality or stroke rates.” [Interact Cardiovasc Thorac Surg 2017;25:659-662]

Cardiac procedure

In earlier studies, CT thorax was found to support routine preoperative planning for redo cardiac surgery in evaluating retrosternal anatomical relations, as well as in minimally invasive or catheter-based cardiac procedures. [Eur J Cardiothorac Surg 1998;13:650-654; Insights Imaging 2013;4:671-689]

Guidelines suggesting the use of CT thorax in routine conventional cardiac surgical procedures done via sternotomy do not yet exist.

“In our institution, the need for CT thorax as part of preoperative planning is left to the discretion of the performing surgeon,” the investigators said.

The current study has several limitations. Firstly, its retrospective observational design is prone to potential selection bias. Secondly, the difference in time period between groups coincides with increased operative procedures done by the surgeon for the CT group. Thirdly, some of the patients did not undergo surgery due to discovery of a porcelain aorta on CT thorax. Finally, the study did not reflect other embolic complications such as mesenteric ischaemia.