Changes in chest compression indexes with breathing underestimate surgical candidacy in patients with pectus excavatum: a computed tomography pilot study

Abstract

Background: Haller Index (HI) ≥3.25 by computed tomography (CT) at end-inspiration has been used to indicate surgical correction in patients with pectus excavatum. However, chest wall diameters vary with breathing and may modify HI values and surgical indications. The aim of our study was to report the changes in HI with breathing and their impact in the surgical indication rates.

Methods: Thirty six patients with pectus excavatum underwent chest CT evaluation at both end-inspiration and end-expiration. HI was derived by dividing the transverse diameter (TD) of the chest by the anteroposterior diameter (APD). Cardiac compression index (CCI) was then calculated by dividing the cardiac TD by the APD.

Results: Mean patient age was 19 ± 7 years old and 86.8% were males. From end-inspiration to end-expiration, large changes in APD values corresponded to large changes (29.6%) in HI values. CCI increased significantly during end-expiration, primarily driven by an increase on the cardiac TD. Surgical indication was found in 71% and 91% of patients during end-inspiration and end-expiration, respectively (p<0.05).

Conclusions: This study showed that the severity indexes of the pectus excavatum were all significantly more severe at end-expiration than at end-inspiration, leading to an increase in surgical candidacy. We therefore recommend performing the CT at end-expiration.

Keywords: Computed tomography; Haller index; Pectus excavatum.