Cardiovascular magnetic resonance assessment of biventricular changes during vacuum bell correction of pectus excavatum

The influence of pectus excavatum on cardiac kinetics and function in otherwise healthy individuals: A systematic review

BACKGROUND

A number of anterior chest wall deformities, most notably pectus excavatum (PE), may have a detrimental effect on cardiac motion and function. Interpretation of transthoracic echocardiography (TTE) and speckle-tracking echocardiography (STE) results may be hampered by the possible influence of PE on cardiac kinetics.

METHODS

A comprehensive search of all articles assessing cardiac function in PE individuals was carried out. Inclusion criteria were: 1) individuals aged >10 years; 2) studies providing objective assessment of chest deformity (Haller index). Studies that measured myocardial strain parameters in PE patients were also included.

RESULTS

The search (EMBASE and Medline) yielded a total of 392 studies, 36 (9.2%) of which removed as duplicates; a further 339 did not meet inclusion criteria. The full-texts of 17 studies were then analyzed. All studies concordantly reported impaired right ventricular volumes and function. With respect to left ventricle (LV), TTE studies uniformly demonstrated a significant impairment in conventional echoDoppler indices in PE individuals, whereas STE studies provided conflicting results. Importantly, LV functional alterations promptly reverted upon surgical correction of chest defect. In subjects with PE of mild-to-moderate severity, we observed that degree of anterior chest wall deformity, as noninvasively assessed by modified Haller index (MHI), was strongly associated with myocardial strain magnitude, in heterogenous cohorts of otherwise healthy PE individuals.

CONCLUSIONS

Clinicians should be aware that in PE individuals, TTE and STE results may not always be indicative of intrinsic myocardial dysfunction, but may be, at least in part, influenced by artifactual and/or external chest shape determinants.

Determinants of success associated with vacuum bell treatment of pectus excavatum

BACKGROUND/PURPOSE

We explored determinants of success in a large cohort of patients with pectus excavatum submitted to vacuum bell treatment and compared groups with satisfactory versus unsatisfactory outcomes.

METHODS

Retrospective case-control study in a single center between May 2013 and January 2020, including patients with pectus excavatum treated with vacuum bell. We classified patients according to their status at closure of data registry (surveillance; withdrawal; complete correction; failure) and according to Obermeyer's classification of degrees of pectus excavatum correction. Determinants of success were calculated using receiver operating characteristic curves.

RESULTS

Overall, 186 patients were included. Complete correction was achieved by 17% of the cases, while 45% remained under surveillance. Failure rates were low (n = 9; 5%), whereas withdrawal rates were 34%. Based on Obermeyer's classification of degree of excavation correction, 35% had excellent/good, 25% fair, and 40% poor/worse results. When comparing patients with good/excellent results with those with unsatisfactory results, patients with good/excellent results had a longer treatment duration [19.0 (13.0; 28) months vs. 13.0 (6.5; 22.5) months, p<0.0001], and lower initial pectus depth [1.6 (1.2; 2.0) cm, vs. 2.0 (1.5; 2.6) cm, p = 0.001]. Using ROC curves, the best determinants of success were an initial pectus depth ≤ 1.8 cm and a length of treatment > 12 months.

CONCLUSION

One-third of patients in treatment with a vacuum bell achieved excellent or good outcomes in our cohort. Determinants of success included an initial pectus depth of 1.8 cm or less and a minimum length of treatment of 12 months.

TYPE OF STUDY

retrospective comparative study LEVEL OF EVIDENCE: III.

Usefulness of strain cardiac magnetic resonance for the exposure of mild left ventricular systolic abnormalities in pectus excavatum

BACKGROUND

Systolic dysfunction in pectus excavatum (PEX) is usually very subtle and mainly focused on the right ventricle (RV), leading to normal or unremarkable cardiac imaging findings unless involving exercise stress.

OBJECTIVES

We evaluated systolic function in PEX using longitudinal strain cardiac magnetic resonance (CMR), a validated parameter for the assessment of the systolic deformation of subendocardial fibers.

METHODS

This prospective registry comprised consecutive patients with PEX who were referred to CMR to define treatment strategies or to establish surgical candidacy. We also included a control group of 15 healthy volunteers without chest wall abnormalities. Using dedicated software, we evaluated the endocardial global longitudinal strain (GLS) of both ventricles and the endocardial global circumferential strain (GCS) of the left ventricle (LV).

RESULTS

A total of 50 patients with PEX comprised the study population, with a mean age of 19.9 ± 8.0 years. The right ventricular ejection fraction (RVEF) of patients with PEX was significantly lower compared to the control group both at end-expiration (59.5 ± 6.8 vs. 64.7 ± 4.7%, p = 0.008) and end-inspiration (56.7 ± 7.2%, vs. 62.7 ± 4.4, p = 0.004); as well as the pulmonary stroke distance (12.6 ± 2.5, vs. 15.0 ± 2.0 cm, p = 0.001). The LV volumetric analysis revealed no differences between PEX and the control group (p > 0.05 for all) regardless of the respiratory cycle, with a mean expiratory LV ejection fraction (LVEF) of 61.4 ± 6.0%. In contrast, the GLS of the LV was significantly lower in PEX compared to controls (-21.2 ± 3.2 vs. -23.7 ± 3.0%, p = 0.010), whereas GCS was similar either at expiration (-28.5 ± 4.0%, vs. -29.5 ± 2.8, p = 0.38) or inspiration (-29.3 ± 4.1%, vs.-28.9 ± 2.3, p = 0.73).

CONCLUSIONS

In this study, we demonstrated that longitudinal strain analysis might enable the detection of very subtle left ventricular systolic function abnormalities in patients with PEX, that are commonly overlooked using the conventional assessment.

LEVEL OF EVIDENCE

II.