Radiologic considerations in patients undergoing the Nuss procedure for 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.

The influence of chest wall conformation on myocardial strain parameters in a cohort of mitral valve prolapse patients with and without mitral annular disjunction

PURPOSE

To evaluate the possible influence of chest wall conformation on myocardial strain parameters in a cohort of mitral valve prolapse (MVP) patients with and without mitral annular disjunction (MAD).

METHODS

All consecutive middle-aged patients with MVP referred to our Outpatient Cardiology Clinic for performing two-dimensional (2D) transthoracic echocardiography (TTE) as part of work up for primary cardiovascular prevention between March 2018 and May 2022, were included into the study. All patients underwent clinic visit, physical examination, modified Haller index (MHI) assessment (the ratio of chest transverse diameter over the distance between sternum and spine) and conventional 2D-TTE implemented with speckle tracking analysis of left ventricular (LV) global longitudinal strain (GLS) and global circumferential strain (GCS). Independent predictors of MAD presence on 2D-TTE were assessed.

RESULTS

A total of 93 MVP patients (54.2 ± 16.4 yrs, 50.5% females) were prospectively analyzed. On 2D-TTE, 34.4% of MVP patients had MAD (7.3 ± 2.0 mm), whereas 65.6% did not. Compared to patients without MAD, those with MAD had: 1) significantly shorter antero-posterior (A-P) thoracic diameter (13.5 ± 1.2 vs 14.8 ± 1.3 cm, p < 0.001); 2) significantly smaller cardiac chambers dimensions; 3) significantly increased prevalence of classic MVP (84.3 vs 44.3%, p < 0.001); 4) significantly impaired LV-GLS (-17.2 ± 1.4 vs -19.4 ± 3.0%, p < 0.001) and LV-GCS (-16.3 ± 4.1 vs -20.4 ± 4.9, p < 0.001), despite similar LV ejection fraction (63.7 ± 4.2 vs 63.0 ± 3.9%, p = 0.42). A-P thoracic diameter (OR 0.25, 95%CI 0.10-0.82), classic MVP (OR 3.90, 95%CI 1.32-11.5) and mitral annular end-systolic A-P diameter (OR 2.76, 95%CI 1.54-4.92) were the main independent predictors of MAD. An A-P thoracic diameter ≤ 13.5 cm had 59% sensitivity and 84% specificity for predicting MAD presence (AUC = 0.81). In addition, MAD distance was strongly influenced by A-P thoracic diameter (r = - 0.96) and MHI (r = 0.87), but not by L-L thoracic diameter (r = 0.23). Finally, a strong inverse correlation between MHI and both LV-GLS and LV-GCS was demonstrated in MAD patients (r = - 0.94 and - 0.92, respectively), but not in those without (r = - 0.51 and - 0.50, respectively).

CONCLUSIONS

A narrow A-P thoracic diameter is strongly associated with MAD presence and is a major determinant of the impairment in myocardial strain parameters in MAD patients, in both longitudinal and circumferential directions.

Modified Haller index validation and correlation with left ventricular strain in a cohort of subjects with obesity and without overt heart disease

The present study was primarily designed to validate the modified Haller index (MHI), the ratio of chest transverse diameter over the distance between sternum and spine, measured by a ruler and transthoracic echocardiography (TTE), respectively, in a cohort of subjects with obesity, but otherwise healthy, by comparing the results to the conventional Haller index (HI) measured on chest X-ray (CXR). 100 consecutive subjects with body mass index (BMI) ≥ 30 kg/m² and 60 matched controls with BMI < 30 kg/m², who underwent a two-plane CXR for any clinical indication, were prospectively examined over a 6-month period. All participants underwent MHI assessment, TTE and speckle-tracking analysis of left ventricular (LV) global longitudinal strain (GLS). Bland-Altman analysis was used to compare the radiological and nonradiological techniques. Second, independent predictors of subclinical myocardial dysfunction, defined as LV-GLS less negative than - 20%, were evaluated. Bland-Altman analysis revealed a bias of - 4.91 cm for latero-lateral thoracic diameter, of - 0.74 cm for antero-posterior (A-P) thoracic diameter and of - 0.22 for HI assessment, suggesting a systematic overestimation of the nonradiological methodology in comparison to that radiological. Despite normal LV systolic function on TTE, LV-GLS resulted impaired in 76% of subjects with obesity. Waist circumference (OR 1.13, 95%CI 1.04-1.22) and nonradiological A-P thoracic diameter (OR 0.51, 95%CI 0.28-0.93) were the main independent predictors of subclinical myocardial dysfunction in subjects with obesity. The impairment in LV myocardial strain detected in subjects with obesity appears to be primarily related to extrinsic abdominal and thoracic compressive phenomena, rather than intrinsic myocardial dysfunction.

Modified Haller index is inversely correlated with true positive exercise stress echocardiographic results

AIMS

The influence of chest wall shape on exercise stress echocardiography (ESE) results has been poorly investigated. We aimed at evaluating the main predictors of true positive (TP)-ESE in a population of subjects with suspected coronary artery disease (CAD), categorized according to chest wall conformation, assessed by modified Haller index (MHI, chest transverse diameter over the distance between sternum and spine).

METHODS

All consecutive patients with suspected CAD referred to our EchoLab for performing ESE between September 2011 and October 2021 were retrospectively enrolled. Preliminary assessment of both pretest probability (PTP) and MHI was performed. All patients with positive ESE underwent coronary angiography. Obstructive CAD was diagnosed by ≥70% stenosis in any epicardial coronary artery. Outcome was TP ESE result.

RESULTS

One thousand two hundred and seventy-five consecutive patients (64.9 ± 13.0 years) entered the study. Subjects with concave-shaped chest wall (MHI > 2.5) (10.7%) and those with normal chest shape (MHI ≤ 2.5) (89.3%) were separately analyzed. PTP was similar in both groups (21.8 ± 13.2 vs. 23.5 ± 13.3%, P  = 0.15). One hundred and seventy patients were diagnosed with positive ESE: 129 (75.9%) had obstructive CAD (TP), whereas the remaining 41 (24.1%) had no CAD. Only 2.3% of TP ESE was detected in subjects with MHI >2.5. PTP [odds ratio (OR) 1.03, 95% confidence interval (CI) 1.01-1.04], dyslipidemia (OR 4.37, 95% CI 2.81-6.80), dyssynergy in the left anterior descending territory (OR 8.21, 95% CI 5.07-13.3) were linearly correlated with TP ESE, whereas MHI >2.5 (OR 0.25, 95% CI 0.14-0.67) was inversely associated with outcome.

CONCLUSIONS

Subjects with MHI >2.5 have low prevalence of TP ESE, regardless of PTP. Preliminary MHI assessment may reduce overestimation of PTP of CAD.

Does chest shape influence exercise stress echocardiographic results in patients with suspected coronary artery disease?

Despite the good specificity of exercise stress echocardiography (ESE) for the detection of coronary artery disease (CAD), false positive (FP) results may occur. We have previously reported that chest abnormalities may affect parameters of cardiac contractility. The influence of chest shape on ESE results has never been previously investigated. We retrospectively analyzed 160 consecutive patients (64.4 ± 13.0-year old, 91 women) who had undergone coronary angiography at our Institution because of positive ESE, between June 2014 and May 2020. Modified Haller index (MHI; chest transverse diameter over the distance between sternum and spine) was assessed in all patients. Obstructive CAD was diagnosed by ≥ 70% stenosis in any epicardial coronary artery. Outcome was false-positivity at ESE. 80.6% of patients were diagnosed with obstructive CAD, while 19.4% had no CAD (FP). We separately analyzed patients with normal chest shape (MHI ≤ 2.5) and those with concave-shaped chest wall (MHI > 2.5). These latter were mostly women with small cardiac chambers, mitral valve prolapse (MVP) and exercise-induced ST-segment changes. Likelihood of false-positivity was significantly higher in subjects with MHI > 2.5 than those with MHI ≤ 2.5 (30.7% vs 9.4%, p = 0.001). By multivariate logistic regression analysis, MHI > 2.5 (OR 4.04, 95%CI 1.45-11.2, p = 0.007), MVP (OR 3.47, 95%CI 1.32-9-12, p = 0.01) and dyssynergy in the left circumflex territory (OR = 3.35, 95%CI 1.26-8.93, p = 0.01) were independently associated with false-positivity. Concave-shaped chest wall (MHI > 2.5) may be associated with false-positive stress echocardiographic result. Mechanisms underpinning this finding need to be further explored.

Does chest wall conformation influence myocardial strain parameters in infants with pectus excavatum?

PURPOSE

To investigate the possible influence of chest wall conformation on myocardial strain parameters in a consecutive population of infants with pectus excavatum (PE), noninvasively assessed by modified Haller index (MHI).

METHODS

Sixteen consecutive PE infants (MHI >2.5) and 44 infants with normal chest shape (MHI ≤2.5) entered in this prospective case-control study. All infants underwent evaluation by neonatologist, transthoracic echocardiography implemented with two-dimensional speckle tracking echocardiography (2D-STE) analysis of both ventricles and MHI assessment (ratio of chest transverse diameter over the distance between sternum and spine), at two time points: within 3 days and at about 40 days of life.

RESULTS

At 2.1 ± 1 days of life, compared to controls (MHI = 2.01 ± 0.2), PE infants (MHI = 2.76 ± 0.2) were diagnosed with significantly smaller cardiac chambers dimensions. Biventricular contractile function and hemodynamics were similar in both groups of infants. Left ventricular (LV) global longitudinal strain (GLS) (-16.0 ± 2.8 vs. -21.7 ± 2.2%), LV-global circumferential strain (GCS) (-16.3 ± 2.7 vs. -24.0 ± 5.2%), LV-global radial strain (GRS) (24.2 ± 3.0 vs. 31.5 ± 6.3%), and right ventricular free wall longitudinal strain (RVFWLS) (-16.0 ± 3.2 vs. -22.3 ± 4.4%) were significantly reduced in PE infants versus controls (all p < 0.001). A strong inverse correlation between MHI and the following parameters: LV-GLS (r = -0.92), LV-GCS (r = -0.88), LV-GRS (r = -0.87), and RVFWLS (r = -0.88), was demonstrated in PE infants, but not in controls, in perinatal period (all p < 0.001). Analogous results were obtained at 36.8 ± 5.2 days after birth.

CONCLUSIONS

Abnormal chest anatomy progressively impairs myocardial strain parameters in PE infants. This impairment might reflect intraventricular dyssynchrony due to compressive phenomena rather than intrinsic myocardial dysfunction.

Influence of chest conformation on ventricular-arterial coupling during normal pregnancy

PURPOSE

There is still controversy regarding the changes of ventricular-arterial coupling (VAC) during normal pregnancy. The possible influence of chest shape on VAC during normal pregnancy has never been investigated.

METHODS

Between October 2019 and June 2020, 59 healthy pregnant women (33.7 ± 4.4 years/old) were consecutively included. They underwent obstetric visit, modified Haller index (MHI) assessment, and complete echocardiographic evaluation with blood pressure measurement to assess arterial elastance (Ea), end-systolic elastance (Ees), and Ea/Ees as an index of VAC, at 12-14 weeks and 36-38 weeks gestation, then 6-9 weeks after delivery.

RESULTS

VAC progressively increased from the first to the third trimester of pregnancy, then decreased in the postpartum (P < 0.0001) in the whole study population. Women with concave-shaped chest wall (MHI >2.5, n = 31) but not women with normal chest shape (MHI ≤2.5, n = 28) showed a progressive increase in VAC during normal pregnancy. Women with MHI >2.5 showed a significantly less pronounced increase in stroke volume index (SVi) from the first to the third trimester of pregnancy. There was a strong linear correlation between third trimester MHI and VAC (r = 0.93).

CONCLUSIONS

Anatomical and/or extrinsic mechanical factors rather than impaired arterial elastance or reduced left ventricular contractility may contribute to changes in VAC during normal pregnancy in women with concave-shaped chest wall.

Lung density analysis using quantitative computed tomography in children with pectus excavatum

Purpose

To evaluate the mean lung density in children with pectus excavatum (PE) and to assess the correlation between the cardiac rotation angle, Haller index, pulmonary function test, and lung density.

Material and methods

This retrospective study included 33 children with PE and 31 healthy controls. The densities of lung parenchyma were evaluated by quantitative computed tomography (CT). Three lung levels were determined: T4 vertebra level, T10 vertebra level, and the level of the measurement of the cardiac rotation angle. The cardiac rotation angle and the Haller index were calculated. All measurements were done by 2 radiologists, independently. Student’s t-test or the Mann-Whitney U test, intraclass correlation coefficients, Pearson or Spearman’s rank correlation coefficient, and Kruskal-Wallis test were used for statistical analysis. A p-value less than 0.05 was considered as statistically significant.

Results

All the lung levels in the PE group had lower mean densities than healthy children, with statistical significance in the right lung at the T10 vertebra level (−818.60 ± 33.49 HU, −798.45 ± 40.24 HU; p = 0.028). There was a correlation between the cardiac rotation angle and the Haller index (r = 0.593; p < 0.001). There were no correlations between mean lung density and cardiac rotation angle, Haller index, and pulmonary function tests.

Conclusions

The lower mean lung densities were found in PE, especially in the right lower lobe. The parenchymal aeration should be considered independently from the severity of PE.

Appropriate use criteria implementation with modified Haller index for predicting stress echocardiographic results and outcome in a population of patients with suspected coronary artery disease

The hypothesis that modified Haller index (MHI) integration with the existing appropriate use criteria (AUC) categories may predict exercise stress echocardiography (ESE) results and outcome of patients with suspected coronary artery disease (CAD) has never been previously investigated. We retrospectively analyzed 1230 consecutive patients (64.8 ± 13.1 years, 58.9% men) who underwent ESE for suspected CAD between February 2011 and September 2019 at our institution. MHI (chest transverse diameter over the distance between sternum and spine) was assessed in all patients. A true positive (TP) ESE was a positive ESE with obstructive CAD according to subsequent coronary angiography. During follow-up time, we evaluated the occurrence of any of the following: (1) cardiovascular (CV) hospitalizations; (2) Cardiac death or sudden death. Overall, 734 (59.7%), 357 (29.0%) and 139 (11.3%) indications for ESE were classified as appropriate (Group 1), rarely appropriate (Group 2) and which may be appropriate (Group 3), respectively. A funnel chest (defined by an MHI > 2.5) was detected in 30.3%, 82.1% and 49.6% of Groups 1, 2 and 3 subjects, respectively (p < 0.0001). On multivariate logistic regression analysis, male sex (OR 1.41, 95%CI 1.02-2.03, p = 0.01) and type-2 diabetes (OR 3.63, 95%CI 2.49-5.55, p = 0.001) were directly correlated to a TP ESE, while "rarely appropriate" indication for ESE with MHI > 2.5 (OR 0.16, 95%CI 0.11-0.22, p < 0.0001) showed a significant inverse correlation with the outcome. During a mean follow-up of 2.5 ± 1.9 years, 299 CV events occurred: 76.4%, 3.5% and 20.1% in Groups 1, 2 and 3, respectively. On multivariate Cox regression analysis, smoking (HR 1.33, 95%CI 1.19-1.48), type 2 diabetes (HR 2.28, 95%CI 1.74-2.97), dyslipidemia (HR 3.51, 95%CI 2.33-5.15), beta-blockers (HR 0.55, 95%CI 0.41-0.75), statins (HR 0.60, 95%CI 0.45-0.80), peak exercise average E/e' ratio (HR 1.08, 95%CI 1.06-1.09), positive ESE (HR 3.12, 95%CI 2.43-4.01) and finally "rarely appropriate" indication for ESE with MHI > 2.5 (HR 0.15, 95%CI 0.08-0.23) were independently associated with CV events. The implementation of AUC categories with MHI assessment may select a group of patients with extremely low probability of both TP ESE and adverse CV events over a medium-term follow-up. A simple noninvasive chest shape assessment could reduce unnecessary exams.

Incidentally Detected Pericardial Defect in a Patient with Pneumothorax as Confirmed on Video-Assisted Thoracoscopic Surgery

Congenital defects of the pericardium, which are generally asymptomatic, are rare disorders characterized by complete or partial absence of the pericardium. Here, we report a rare case of a 19-year-old male who was incidentally diagnosed with congenital absence of the left pericardium during examination for symptoms of pneumothorax. Chest radiography and computed tomography revealed a collapsed left lung without any evidence of trauma, no unusual findings of free air spaces along the right side of the ascending aorta, heart shifted toward the left side of the thorax, and a shallow chest. Subsequent thoracoscopy confirmed the absence of the left pericardium and displacement of the heart toward the left thoracic cavity. We further discuss the correlation between radiologic images and surgical findings of a congenital pericardial defect associated with spontaneous pneumothorax.

Influence of chest conformation on myocardial strain parameters in healthy subjects with mitral valve prolapse

Chest shape might affect myocardial strain parameters. However, the relationship between myocardial strain parameters and chest conformation has not been previously investigated in subjects with mitral valve prolapse (MVP). Between April 2019 and May 2020, 60 healthy subjects (50.1 ± 8.6 year/old, 46.6% females) with MVP and mild-to-moderate mitral regurgitation, and 60 controls matched by age, sex, and cardiovascular risk factors were consecutively studied. Participants underwent modified Haller index (MHI) assessment (ratio of chest transverse diameter over the distance between sternum and spine), and transthoracic echocardiography implemented with 2D-speckle tracking analysis. MHI was significantly greater in MVP group than controls (2.6 ± 0.35 vs 2.1 ± 0.23, p < 0.0001). Left ventricular (LV) ejection fraction was similar in MVP and controls (63.5 ± 3.7% vs 64.3 ± 3.9%, p = 0.25). LV regional and global longitudinal (GLS), circumferential (GCS) and radial strain (GRS) parameters and LV peak twist were all significantly lower in MVP compared to controls (all p < 0.0001). MVP subjects with a tight chest (MHI > 2.5, n = 30), and those with MHI ≤ 2.5 (n = 30) were then separately analyzed. A significant impairment in myocardial strain parameters and LV peak twist was documented in MVP subjects with MHI > 2.5, but not in those with MHI ≤ 2.5. MHI showed a strong inverse correlation with LV-GLS (r = - 0.85), GCS (r = - 0.84), GRS (r = - 0.84) and LV peak twist (r = - 0.94). In MVP subjects, impairment of myocardial strain parameters is not due to intrinsic reduction of cardiac contractility function, but it appears to be related to the degree of chest deformity.

Nuss procedure: Technical modifications to ease bending of the support bar and lateral stabilizer placement

BACKGROUND

Modifications defined to ease bending of the support bar and lateral stabilizer placement during minimal invasive repair of pectus excavatum (MIRPE) have not been reported. We herein report our experience with MIRPE including several technical modifications.

METHODS

A total of 87 patients who underwent MIRPE were evaluated retrospectively. Technical modifications are (1) a template drawn preoperatively according to the anthropometric measurements, (2) more laterally placed thoracal incisions, (3) single existing incision for multiple support bars, (4) to secure lateral stabilizers to support bar in inverted position.

RESULTS

The mean patient age was 11.2 ± 3.8 years. The mean operating time was 63.7 ± 18.7 min. The mean Haller index was 5.4 ± 2.1. Eight patients necessitated two support bars. The support bars were removed in 69 patients after the completion of treatment. Support bars were left in place 26.8 ± 4.3 months. Final chest contours of the 56 patients were evaluated as 12 months passed after support bar removal and excellent repair results were determined in 84.2%.

CONCLUSION

Preoperative bending of the support bar according to anthropometric measurements and fixation of the lateral stabilizers to the support bar in inverted position facilitates bar shaping and lateral stabilizer placement.

Pectus excavatum severity underestimated due to lack of objective measures in radiological reports

During a routine physical examination, the degree of pectus excavatum (PE) is not always appreciated as the external appearance does not always reflect the severity of the deformity. In the patient in this case report, the severity had been underestimated for 33 years. The physicians, having requested standard two-view chest radiographs, had relied solely on the radiological reports, where the PE had been ambiguously described as 'moderate' or 'substantial'. In patients where PE has been observed, it is essential that an objective numeric measure of severity, using the Haller index, is included in radiological reports.

Pectus excavatum

In pectus excavatum, a developmental chest-wall deformity that affects approximately one in 400 births, the sternum is depressed inward and the ribs protrude anteriorly. This deformity can compromise pulmonary and/or cardiac function. It can also produce a characteristic radiographic appearance on frontal radiographs, which may be mistaken for right-middle-lobe opacification from pneumonia or atelectasis. I present a case of pectus excavatum in a teenage female with characteristic imaging findings, and the disposition of the case.

Correction of pectus excavatum with breast hypoplasia using simultaneous pectus bar procedure and augmentation mammoplasty

Most women with asymmetric pectus excavatum suffer from hypoplastic breasts. Hence, aesthetic correction of pectus excavatum has to address thoracic wall deformity, breast hypoplasia, and asymmetry.In retrospective series, 21 patients with a diagnosis of pectus excavatum with hypoplastic breasts were corrected using the pectus bar procedure and subpectoral augmentation mammoplasty. Results were assessed by analyzing prospectively collected data and calculating pectus indices from computed tomographic scans. At 12 months postoperatively, cosmetic evaluations were performed by the patients and by an independent, board-certified plastic surgeon using score from 0 (very poor) to 4 (very good).Cosmetic results evaluated by plastic surgeon were good (3.33 ± 0.03) and patient satisfaction was high (3.52 ± 0.03). Furthermore, indices of pectus excavatum were corrected to near normal.The authors consider that the pectus bar procedure with subpectoral augmentation mammoplasty is useful for the aesthetic correction of pectus excavatum with hypoplastic breasts.

The nuss procedure after breast augmentation for female pectus excavatum

Pectus excavatum, the most common congenital chest wall malformation, has a higher incidence among men. Since 1987, when Donald Nuss performed his technique for the first time, the minimally invasive approach has become the most widely used technique for treating pectus excavatum. Few reported studies have focused on the repair of female pectus excavatum. Women with pectus excavatum often present with breast asymmetry that may require breast augmentation, either before or after pectus excavatum repair. To the authors' knowledge, no reports on the Nuss procedure after breast implant surgery have been published. This report describes the case of a 26-year-old woman who underwent minimally invasive repair after breast implant surgery. The authors believe that for women with severe pectus excavatum, the Nuss procedure should be the first choice for surgical correction. Moreover, for breast implant patients, this technique is absolutely feasible without major complications.