Cardiopulmonary Function in Thoracic Wall Deformities: What Do We Really Know?

Unsophisticated assessment of the cardiopulmonary function in patients with pectus excavatum using the six minute walk test

BACKGROUND

We explored whether the maximum predicted walking distance, assessed with six-minute walk test (6MWT) and reflecting submaximal functional exercise capacity, is decreased among patients with pectus excavatum (PEX).

METHODS

This study comprised a retrospective analysis of patients with PEX who underwent a 6MWT for the assessment of functional capacity. The maximum distance walked was recorded and compared to reference values established for different populations, including a young and healthy South American population.

RESULTS

We included 43 patients with PEX who underwent 6MWT. The mean age was 17.8 ± 6.7 years. The mean maximum distance walked was significantly lower than the predicted distance (600.8 ± 67.6 metres vs. 729.8 ± 67.5 metres, p < 0.0001). Using the Enright reference equation including an older reference population, the mean negative difference was higher (PEX patients walked 190.4 ± 78.4 metres less than predicted, p < 0.0001). We also applied the Li et al. reference equation accounting for sex among other variables, detecting a decreased walked distance compared to the gender-adjusted predicted distance (PEX patients walked a mean 222.4 ± 87.4 metres less than predicted, p < 0.0001). Using the Ulrich et al. equation, PEX patients walked a mean 114.2 ± 85.1 metres less than predicted (p < 0.0001). Although of uncertain clinical relevance, there was a significant decrease in the mean oxygen saturation after exercise (baseline 97.4 ± 1.2%, vs. final 96.4 ± 2.1%, p = 0.006).

CONCLUSIONS

In this study, we identified a significant reduction in the maximum walked distance among patients with PEX compared to the predicted distance, thus potentially emerging as an unsophisticated means to evaluate and quantify functional exercise capacity.

Does a high Haller index influence outcomes in pectus excavatum repair?

OBJECTIVE

Severity for pectus excavatum includes Haller index (HI) > 3.25. An extremely high HI (≥8) may influence surgical approach and complications. This study reviews outcomes of patients with high HI after repair.

METHODS

A single institution retrospective analysis was performed on adult patients with HI ≥ 8 undergoing pectus excavatum repairs. For outcomes, a propensity score-matched control group with a HI ≤ 4 was utilized.

RESULTS

In total, 64 cases (mean age, 33.5 ± 10.9 years; HI, 13.1 ± 5.0; 56% women) were included. A minimally invasive repair was successful in 84%. A hybrid procedure was performed in the remaining either to repair fractures of the ribs (8 patients) and sternum (5 patients) or when osteotomy and/or cartilage resection was required (10 patients). In comparison with the matched cohort (HI ≤ 4), patients with high HI had longer operative times (171 vs 133 minutes; P < .001), more frequently required hybrid procedures (16% vs 2%; P = .005), experienced higher incidences of rib (22% vs 3%; P = .001) and sternal fractures (12% vs 0%; P = .003), and had increased repair with 3 bars (50% vs 19%; P < .001). There were no significant differences between the groups for length of hospital stay or postoperative 30-day complications.

CONCLUSIONS

Patients with an extremely high HI can be challenging cases with greater risks of fracture and need for osteotomy/cartilage resection. Despite this, minimally invasive repair techniques can be utilized in most cases without increased complications when performed by an experienced surgeon.

Left Ventricular Global Longitudinal Strain as a Parameter of Mild Myocardial Dysfunction in Athletes after COVID-19

Whether symptoms during COVID-19 contribute to impaired left ventricular (LV) function remains unclear. We determine LV global longitudinal strain (GLS) between athletes with a positive COVID-19 test (PCAt) and healthy control athletes (CON) and relate it to symptoms during COVID-19. GLS is determined in four-, two-, and three-chamber views and assessed offline by a blinded investigator in 88 PCAt (35% women) (training at least three times per week/>20 MET) and 52 CONs from the national or state squad (38% women) at a median of two months after COVID-19. The results show that the GLS is significantly lower (GLS -18.53 ± 1.94% vs. -19.94 ± 1.42%, p < 0.001) and diastolic function significantly reduces (E/A 1.54 ± 0.52 vs. 1.66 ± 0.43, p = 0.020; E/E'l 5.74 ± 1.74 vs. 5.22 ± 1.36, p = 0.024) in PCAt. There is no association between GLS and symptoms like resting or exertional dyspnea, palpitations, chest pain or increased resting heart rate. However, there is a trend toward a lower GLS in PCAt with subjectively perceived performance limitation (p =0.054). A significantly lower GLS and diastolic function in PCAt compared with healthy peers may indicate mild myocardial dysfunction after COVID-19. However, the changes are within the normal range, so that clinical relevance is questionable. Further studies on the effect of lower GLS on performance parameters are necessary.

Machine Learning: Using Xception, a Deep Convolutional Neural Network Architecture, to Implement Pectus Excavatum Diagnostic Tool from Frontal-View Chest X-rays

Pectus excavatum (PE), a chest-wall deformity that can compromise cardiopulmonary function, cannot be detected by a radiologist through frontal chest radiography without a lateral view or chest computed tomography. This study aims to train a convolutional neural network (CNN), a deep learning architecture with powerful image processing ability, for PE screening through frontal chest radiography, which is the most common imaging test in current hospital practice. Posteroanterior-view chest images of PE and normal patients were collected from our hospital to build the database. Among them, 80% were used as the training set used to train the established CNN algorithm, Xception, whereas the remaining 20% were a test set for model performance evaluation. The performance of our diagnostic artificial intelligence model ranged between 0.976–1 under the receiver operating characteristic curve. The test accuracy of the model reached 0.989, and the sensitivity and specificity were 96.66 and 96.64, respectively. Our study is the first to prove that a CNN can be trained as a diagnostic tool for PE using frontal chest X-rays, which is not possible by the human eye. It offers a convenient way to screen potential candidates for the surgical repair of PE, primarily using available image examinations.

Respiratory Function Tolerance of Rats with Vaying Degrees of Thoracic Volume Reduction

OBJECTIVE

To compare the effects of respiratory function on different degrees of reduced thoracic volume and evaluate the tolerance of rats with reduced thoracic volume, and to assess the feasibility of thoracic volume as a measure of the severity of rib fractures.

METHODS

A total of 24 10-week-old female Sprague-Dawley (SD) rats were randomly divided into four groups (n = 6 in each group) according to the displacement degree of bilateral rib fractures (2, 4, 6, and 8 mm). The respiratory function of the rats（Tidal volume, Inspiration time, Expiration time, Breath rate, Minute volume, Peak inspiration flow) measured via whole-body barometric plethysmography before and after operation for 14 consecutive days. Respiratory function parameters of each group were analyzed. Chest CT scans were performed before and 14 days after operation, after that we reconstructed three-dimensional of the thoracic and lung and measured their volumes by computer software. We calculated the percentage of thoracic and lung volume reduction after operation.

RESULTS

At the 14th day after the operation, the decline of thoracic volume rates of in the 2, 4, 6, and 8 mm groups were 5.20%, 9.01%, 16.67%, and 20.74%, respectively. The 8 mm group showed a significant reduction in lung volume. The postoperative tidal volumes were lower in each of the groups than the baseline values before the operation. The tidal volume of the 2 mm group gradually recovered after the operation and returned to a normal level (1.54 ± 0.07 mL) at 14th day after the operation. The tidal volume of the 4, 6, and 8 mm groups recovered gradually after the operation, but did not return to baseline level at the 14th day. In particular, the tidal volume of the 8 mm group was significantly lower than that of the other groups during the 14 days (1.23 ± 0.12 mL, p < 0.05). There were no significant changes in the inspiratory and expiratory times, peak inspiratory and expiratory flows, respiratory rate, and minute ventilation during the 14 days after the operation in each group.

CONCLUSIONS

Displaced rib fractures lead to thoracic collapse and reduced thoracic volume, which can affect tidal volume in rats. The greater the decrease of thoracic volume, the more obvious the decrease of early tidal volume. The thoracic volume can be used as an objective parameter to evaluate the severity of multiple rib fractures. Early operation to restore thoracic volume may improve early respiratory function. Decreased thoracic volume affected respiratory function and can be compensated and recovered in the long term.

Separation of the seventh costal-sternal junction-A new technique to improve outcomes for the Nuss procedure for pectus excavatum

BACKGROUND

In the standard Nuss procedure for pectus excavatum, the costal arch is often elevated together with the sternum, resulting in unevenness of the lower part of the thorax. This complication is commonly called rib flaring. This paper presents a technique to avoid rib flaring and evaluates its effectiveness.

MATERIALS AND METHODS

In our technique, a part of the seventh costal cartilage is removed, disconnecting the costal arch from the sternum. The effectiveness of this technique was evaluated in a retrospective clinical study of 63 pectus excavatum patients who were randomly collected and were divided into two groups. One group-defined as the Standard Group-includes 27 patients (29.8 ± 6.5SD y/o) on whom standard Nuss procedure was conducted; the other group-defined as the Separation Group-includes 36 patients (31.8 ± 6.1SD y/o) on whom the cartilage removal was conducted in addition to the standard Nuss procedure. The degree of postoperative costal-arch elevation was defined as ECA (Elevation of Costal Arch) and was compared between the two groups.

RESULTS

ECA was significantly greater for the Standard Group (10.2 ± 3.3SD mm) than for the Separation Group (-1.1 ± 3.42SDmm).

CONCLUSION

Postoperative protrusion of the costal arch is prevented by the separation of the seventh costal cartilage from the sternum. Our original technique is a useful option for the treatment of pectus excavatum.

Molecular Approaches and Echocardiographic Deformation Imaging in Detecting Myocardial Fibrosis

The pathological remodeling of myocardial tissue is the main cause of heart diseases. Several processes are involved in the onset of heart failure, and the comprehension of the mechanisms underlying the pathological phenotype deserves special attention to find novel procedures to identify the site of injury and develop novel strategies, as well as molecular druggable pathways, to counteract the high degree of morbidity associated with it. Myocardial fibrosis (MF) is recognized as a critical trigger for disruption of heart functionality due to the excessive accumulation of extracellular matrix proteins, in response to an injury. Its diagnosis remains focalized on invasive techniques, such as endomyocardial biopsy (EMB), or may be noninvasively detected by cardiac magnetic resonance imaging (CMRI). The detection of MF by non-canonical markers remains a challenge in clinical practice. During the last two decades, two-dimensional (2D) speckle tracking echocardiography (STE) has emerged as a new non-invasive imaging modality, able to detect myocardial tissue abnormalities without specifying the causes of the underlying histopathological changes. In this review, we highlighted the clinical utility of 2D-STE deformation imaging for tissue characterization, and its main technical limitations and criticisms. Moreover, we focalized on the importance of coupling 2D-STE examination with the molecular approaches in the clinical decision-making processes, in particular when the 2D-STE does not reflect myocardial dysfunction directly. We also attempted to examine the roles of epigenetic markers of MF and hypothesized microRNA-based mechanisms aiming to understand how they match with the clinical utility of echocardiographic deformation imaging for tissue characterization and MF assessment.

Cardiopulmonary Outcomes After the Nuss Procedure in Pectus Excavatum

Background

Pectus excavatum is the most common chest wall deformity. There is still controversy about cardiopulmonary limitations of this disease and benefits of surgical repair. This study evaluates the impact of pectus excavatum on the cardiopulmonary function of adult patients before and after a modified minimally invasive repair.

Methods and Results

In this retrospective cohort study, an electronic database was used to identify consecutive adult (aged ≥18 years) patients who underwent cardiopulmonary exercise testing before and after primary pectus excavatum repair at Mayo Clinic Arizona from 2011 to 2020. In total, 392 patients underwent preoperative cardiopulmonary exercise testing; abnormal oxygen consumption results were present in 68% of patients. Among them, 130 patients (68% men, mean age, 32.4±10.0 years) had post‐repair evaluations. Post‐repair tests were performed immediately before bar removal with a mean time between repair and post‐repair testing of 3.4±0.7 years (range, 2.5–7.0). A significant improvement in cardiopulmonary outcomes (P<0.001 for all the comparisons) was seen in the post‐repair evaluations, including an increase in maximum, and predicted rate of oxygen consumption, oxygen pulse, oxygen consumption at anaerobic threshold, and maximal ventilation. In a subanalysis of 39 patients who also underwent intraoperative transesophageal echocardiography at repair and at bar removal, a significant increase in right ventricle stroke volume was found (P<0.001).

Conclusions

Consistent improvements in cardiopulmonary function were seen for pectus excavatum adult patients undergoing surgery. These results strongly support the existence of adverse cardiopulmonary consequences from this disease as well as the benefits of surgical repair.

Chest Pain and Dyspnea After a Minimally Invasive Repair of Pectus Excavatum

Although infrequent, damage to cardiovascular structures can occur during or following a minimally invasive repair of pectus excavatum. We present a case of right ventricular outflow tract compression caused by a displaced intrathoracic bar. Removal of the bar resulted in an improvement in symptoms and hemodynamics. (Level of Difficulty: Advanced.)

Differential Influence of Physical Activity on Cardiopulmonary Performance and Stroke Volume Assessed at Cardiopulmonary Exercise Test in Pectus Excavatum: A Pilot Study

Background

Exercise training increases muscle VO₂ by increasing O₂ transport and O₂ uptake while cardiac output increase might be limited by the conformation of the chest in subjects with pectus excavatum (PE).

Aims

The aim of the present study was to investigate the influence of physical activity (PA) on functional parameters of cardiopulmonary performance and stroke volume obtained at Cardiopulmonary Exercise Test (CPET) in PE.

Methods and Procedures

A cohort of adolescents (15 with PE and 15 age- and sex-matched healthy controls, HC) underwent Cardiopulmonary Exercise Test (CPET) and administration of the International Physical Activity Questionnaire – Short Form (IPAQ-SF) with estimation of weekly PA (METs h^–1⋅week^–1). Determinants of CPET parameters were investigated with multivariable linear regression analysis.

Results

As expected, when compared to HC, PE had lower VO₂ max (37.2 ± 6.6 vs. 45.4 ± 6.4 mL⋅kg^–1⋅min^–1, p < 0.05), and VO₂/HR max (O₂ pulse, 12.1 ± 2.4 vs. 16.2 ± 3.6 mL⋅min^–1⋅bpm^–1, p < 0.05). Importantly, physical activity level was a predictor of VO₂ max (adjusted for sex, body mass index, FEV₁%, and presence of PE, β = 0.085; 95% Cl 0.010 to 0.160, p = 0.029) whereas O₂ pulse was independent from PA level (β = 0.035; 95% Cl −0.004 to 0.074).

Conclusion

Physical activity is a determinant of VO₂ max (cardiopulmonary performance), whereas it appears not to affect O₂ pulse (a measure of stroke volume at peak exercise) related to constrained diastolic filling in PE.

Clinical Evaluation of Exertional Dyspnea in Adult Pectus Excavatum Patients

Abstract:

Evaluation of patients with pectus excavatum has primarily been focused on the pediatric population who undergo surgical correction of sternal defects mainly for cosmetic reasons combined with exercise-limiting symptoms. The extent of cardiopulmonary improvement in this population based on cardiac imaging, pulmonary function testing, and cardiopulmonary exercise testing may be highly variable. There is no current consensus on the limitations of cardiopulmonary impairment or potential improvement from surgical repair in pediatric patients. Limited data has published in the medical literature on the evaluation of adults with pectus excavatum who may also present with a variety of clinical symptoms. Adult patients with exercise limitation and pectus excavatum may present with exertional dyspnea, chest discomfort, palpitations/tachycardia, exercise-induced wheezing, and use of bronchodilators for asthma-like symptoms. While numerous published review articles outline clinical evaluation and surgical treatment for younger patients, comprehensive evaluation for these adult patients has not been fully elucidated. There is no current consensus on the underlying cause of cardiopulmonary impairment in adult patients or their potential improvement from surgical repair. This review focuses on the recommended evaluation of adult patients to discern the potential cardiopulmonary limitations to exercise due to pectus excavatum, especially in physically fit adults such as active duty military personnel. Two illustrative cases are presented to describe the complexity of the evaluation of adult patients and potential need for surgical correction.

The questionable benefit of pectus excavatum repair on cardiopulmonary function: a prospective study

 

OBJECTIVES

Since the introduction of the minimally invasive technique for repair of pectus excavatum (MIRPE), increasing numbers of patients are presenting for surgery. However, controversy remains regarding cardiopulmonary outcomes of surgical repair. Therefore, the aim of our prospective study was to investigate cardiopulmonary function, at rest and during exercise before surgery, first after MIRPE and then after pectus bar removal.

METHODS

Forty-seven patients were enrolled in a prospective, open-label, single-arm, single-centre clinical trial (Impact of Surgical Treatments of Thoracic Deformation on Cardiopulmonary Function) [NCT02163265] between July 2013 and November 2019. All patients underwent a modified MIRPE technique for surgical correction of pectus excavatum (PE), called Minor Open Videoendoscopically Assisted Repair of Pectus Excavatum. The patients underwent pre- and postoperative chest X-ray, three-dimensional volume-rendering computer tomography thorax imaging, cardiopulmonary function tests at rest and during stepwise cycle spiroergometry (sitting and supine position) and Doppler echocardiography. Daily physical activity questionnaires were also completed.

RESULTS

The study was completed by 19 patients (15 males, 4 females), aged 13.9–19.6 years at the time of surgery. The surgical patient follow-up was 5.7 ± 7.9 months after pectus bar removal. No significant differences in cardiopulmonary and exercise parameters were seen after placement of the intrathoracic bar, or after pectus bar removal, compared to presurgery.

CONCLUSIONS

Our findings indicate that surgical correction of PE does not impair cardiopulmonary function at rest or during exercise. Therefore, no adverse effects on exercise performance should be expected from surgical treatment of PE via the modified MIRPE technique.

Clinical trial registration number

clinicaltrials.gov [ClinicalTrials.gov number, NCT02163265].

Trends in the Treatment of Pectus Excavatum in the Netherlands

INTRODUCTION

 Pectus excavatum (PE) is the most common deformity of the anterior chest wall and can be corrected surgically with different techniques. In the past years, medical literature suggests that the minimal invasive surgical correction of PE (MIRPE) has currently become the operation technique of choice in Europe, and the number of PE patients undergoing surgery has increased. The aim of this study was to evaluate trends in the number of patients operated on and the surgical techniques generally used in patients with PE in the Netherlands.

MATERIALS AND METHODS

 From the registration by Statistics Netherlands, the numbers of live births and gender were obtained for the period 1980 to 2017. Furthermore, from the Dutch hospital registration performed by Kiwa Prismant systems, the number of total surgical procedures of PE patients from the period 1998 to 2017, and the numbers of open and MIRPE surgery were obtained over the period 2005 to 2013.

RESULTS

 The birth rate in Netherlands has stayed more or less stable in the last two decades. The number of PE patients asking for correction, however, has increased. In addition, the percentage of thoracoscopic assisted correction has increased.

CONCLUSION

 The increase in correction of PE is not due to an increased incidence but to an increase of patient wishes. The use of MIRPE is gaining popularity over time.

Transesophageal echocardiography during pectus excavatum correction in children: What happens to the heart?

OBJECTIVES

Cardiac compression in pectus excavatum remains difficult to evaluate. We describe the findings with intraoperative transesophageal echocardiography during pectus excavatum correction in pediatric patients.

METHODS

We studied right heart changes during surgical correction of pectus excavatum by transesophageal echocardiograph. Four-D echo was associated to assess morphology of the tricuspid annulus.

RESULTS

Twenty patients were included, mean age 13.5 (+/- 2.9). Mean preoperative Haller Index was 6.3 (+/- 2.63) and mean Correction Index 47.63% (+/- 12.4%). Preoperative transthoracic echocardiography at rest showed mild right heart compression in 6. Correction was gained by Nuss technique in 19, and Taulinoplasty in one. Initial transesophageal echocardiography showed compression of the right heart and deformation of the tricuspid annulus in all. During the sternal elevation, diameters of right atrium, ventricle and tricuspid annulus significantly improved: mean augmentation of right ventricle was 5.78 mm (+/- 3.56 p < 0.05), right atrium 6.64 mm (+/- 5.55 p < 0.05) and tricuspid annulus 6.02 mm (+/- 3.29 p < 0.05). The morphology of the tricuspid annulus in 4D normalized.

CONCLUSIONS

Preoperative transthoracic echocardiography at rest underestimates right chamber compression in pediatric patients with pectus excavatum. Surgical correction improves diameters of the right ventricle, right atrium and tricuspid annulus and normalizes the morphology of the tricuspid annulus (4D).

LEVEL OF EVIDENCE

Level III.

The strain and strain rate imaging paradox in echocardiography: overabundant literature in the last two decades but still uncertain clinical utility in an individual case

Almost two decades ago strain and strain rate imaging were proposed as a new, potentially more sensitive modality for quantifying both regional and global myocardial function. Until now, however, strain and strain rate imaging have been slow to be incorporated into everyday clinical practice. More recently, two dimensional strain has been claimed as of greater clinical utility, given that it is angle independent, with improved feasibility and reproducibility as compared to tissue Doppler strain. Nevertheless, speckle tracking strain is reliant on 2D image quality and frame rates. Three dimensional speckle tracking could eliminate the problem of through-plane motion inherent in 2D imaging, but 3D strain is currently limited by low frame rates. Another limitation of strain imaging is that the results are dependent on the ultrasound machine on which analyses are performed, with variability in measurements between different vendors. Despite the diagnostic and prognostic advantages of 2D strain, there is a lack of specific therapeutic interventions based on strain and a paucity of long-term large-scale randomized trial evidence on cardiovascular outcomes. After overabundant literature the same definition of normal cut-off values is controversial and not univocal. Further studies are needed, involving both manufacturers and medical professionals, on the additive contribution, possibly different case by case, of interfering and artifactual factors, aside from myocardial function per se. These artifactual determinants and motion artifacts components could be dominant in individual cases and should always be taken into account in the clinical decision making process in a single case.

Diastolic and Systolic Cardiac Dysfunction in Pectus Excavatum: Relationship to Exercise and Malformation Severity

Purpose

To explore stress echocardiographic findings among patients with pectus excavatum (PEX) and their relationship with malformation severity.

Materials and Methods

A prospective registry involving consecutive patients with a diagnosis of isolated PEX referred to undergo chest CT and stress echocardiography to evaluate surgical candidacy and/or to define treatment strategies was developed. Malformation indexes were evaluated using chest CT.

Results

This study included 269 patients with PEX (19.7 years ± 7.8 [standard deviation]; 245 men) and 35 healthy volunteers (20.7 years ± 6.1; 21 men). Patients with PEX achieved a lower maximal workload (PEX group, 8.2 metabolic equivalents ± 1.7; control group, 11.8 metabolic equivalents ± 5.5; P < .0001). This study identified evidence of abnormal right ventricular diastolic function in 29% of patients with PEX and identified no evidence of this among those in the control group (P < .0001). Healthy controls showed a 37% increment in the tricuspid area during exercise, compared with 4% in patients with PEX (P = .002). Right ventricular systolic function was significantly lower in patients with PEX than in controls, both measured using tricuspid annulus plane systolic excursion (stress, 25.0 mm ± 5.5 vs 35.4 mm ± 3.7; P < .0001), and the tricuspid systolic wave was also smaller (stress, 16.9 cm/sec ± 4.5 vs 20.5 cm/sec ± 3.9; P < .0001). During stress, significant associations were detected between malformation indexes with right ventricular systolic and diastolic findings (P < .05 for all).

Conclusion

This study identified evidence of diverse adverse functional and morphologic cardiac manifestations in PEX, involving signs of abnormal diastolic and systolic right ventricular function and compression of the atrioventricular groove, which worsened during stress and were related to malformation severity.© RSNA, 2020: An earlier incorrect version of this article appeared online. This article was corrected on October 19, 2020.

Assessment of thoracic volume changes after the collapse of lateral rib fractures based on chest computed tomography data: computer simulation and a multiple variable linear regression analysis

Background

Chest blunt trauma (CBT) and the resultant rib fractures often lead to thoracic collapse. The purpose of this study was to explore the effect of displacement of the rib fracture and thoracic collapse on the thoracic volume by using normal chest CT data.

Methods

In this retrospective study, seven consecutive normal participants were selected from our hospital between June and July 2018. Normal thoracic models were reconstructed, followed by simulation of lateral fractures through the 4th to 9th ribs under three collapse modes with 1–5 cm of collapse. The thoracic collapse models (n = 630) were reconstructed using 3Dmax 2014. We calculated the thoracic volume and reduction percentage for each thoracic collapse model. Linear regression-based comparisons of thoracic volume reductions were performed.

Results

In all three collapse modes, the degree of the collapse was linearly correlated with the mean thoracic volume reduction. The reduction percentage in the posterior collapse mode was higher than that in the anterior collapse mode (P < 0.001). The largest volume reductions in the anterior, posterior, and simultaneous collapse models were in the 6th rib fracture model (P < 0.001), 8th rib fracture model (P < 0.001), and 7th rib fracture model (P < 0.001), respectively.

Conclusions

The influences of rib fracture displacement and collapse on the thoracic volume in the 6th through 8th ribs are critical in lateral rib fractures. For patients with 6th to 8th rib fractures and posterior rib collapse, surgical intervention to restore thoracic volume may be more essential.

Cardiopulmonary resuscitation in pediatric pectus excavatum patients-Where is the heart?

BACKGROUND

In children with pectus excavatum, the posteriorly depressed sternum compresses and displaces the heart. However, the currently recommended compression site and depth for cardiopulmonary resuscitation have not been studied in this population.

AIM

This retrospective study investigated the location of the center of ventricles with the largest cross-sectional area to determine the optimal site and depth for chest compressions in pediatric pectus excavatum patients.

METHODS

Chest computed tomography images of 94 pediatric pectus excavatum patients before and after correction surgery were compared with normal patients. The caudal displacement of the ventricles was calculated by dividing the length of sternum by the length from the suprasternal notch to the transverse level of the largest cross-sectional area of the ventricles. The proportional leftward deviation of the center of the ventricles from the midline versus transverse diameter of the thorax was calculated. The remaining internal thickness was calculated at the midline assuming the recommended compression depth of one-third of the anterior to posterior diameter.

RESULTS

Compared with the normal population (mean = 81% [SD = 10.3%]), pediatric pectus excavatum patients showed caudal displacement of ventricles before (98.2% [15.1%], 95% CI of mean difference; 13.7%-20.5%, P < .001) and after correction (100.4% [13.5%], 95% CI of mean difference; 16.2%-22.5%, P < .001). Compared with the normal population (6.9% [2.7%]), pediatric pectus excavatum patients showed leftward deviation of ventricles before (16.2% [5.5%], 95% CI of mean difference; 8.2%-10.4%, P < .001) and after correction (13.3% [4.8%], 95% CI of mean difference; 5.3%-7.3%, P < .001). The remaining internal thickness assuming the recommended chest compression was <10 mm in 54/94(57.4%) and 18/94 (19.1%) of pediatric pectus excavatum patients before and after correction, respectively.

CONCLUSIONS

Pediatric pectus excavatum patients showed significant caudal displacement and leftward deviation of the ventricles compared with the normal population despite correction surgery and the currently recommended compression site and depth might injure intrathoracic structures without effective cardiac compression during cardiopulmonary resuscitation.

Reduced Myocardial Strain Parameters in Subjects With Pectus Excavatum: Impaired Myocardial Function or Methodological Limitations Due to Chest Deformity?

Pectus excavatum (PE) may cause symptoms and alter cardiopulmonary function. Left ventricular (LV) and right ventricular (RV) function have been reported to be impaired in PE subjects. However, this issue has not been systematically investigated with respect to the degree of chest wall abnormality. We aimed to evaluate the influence of severity of chest shape abnormality on myocardial strain parameters in PE subjects. We studied 30 healthy subjects (55.8 ± 14.0 year/old, 18 males) with PE, assessed by the ratio of chest transverse diameter over the distance between sternum and spine (modified Haller index, MHI, >2.5), and 30 controls (MHI ≤2.5) matched by age, sex, and cardiovascular risk factors. Participants underwent 2-dimensional (2D) transthoracic echocardiography implemented with 2D-speckle tracking echocardiography. Right-heart and left-heart chamber dimensions, and stroke volume, were significantly reduced in PE subjects (all P< 0.0001). While LV ejection fraction, E/A, and E/e', did not significantly differ between the 2 groups, all LV and RV strain and strain rate parameters were severely reduced in subjects with PE (P < 0.0001). Importantly, in PE subjects, but not in controls, LV global longitudinal strain, LV global circumferential strain, LV global radial strain, and RV free wall systolic strain, were all linearly correlated to MHI (all P < 0.0001). In healthy subjects with PE, abnormal chest anatomy progressively impairs myocardial strain. However, this impairment is not due to subclinical myocardial dysfunction; it might reflect intraventricular dyssynchrony due to compressive phenomena, or technical limitations of strain methodology, due to chest wall abnormality.

Sternal torsion in pectus excavatum is related to cardiac compression and chest malformation indexes

BACKGROUND/PURPOSE

The role of sternal torsion (ST) in patients with pectus excavatum (PEX) is unknown. We evaluated the relationship between ST and both chest malformation and cardiac compression (CC) indexes.

METHODS

We included consecutive patients with PEX who underwent chest computed tomography and cardiac magnetic resonance (CMR) to define surgical candidacy. Malformation indexes included the Haller index (HI), correction index (CI), and ST. CC and the tricuspid to mitral annulus width ratio were evaluated using CMR.

RESULTS

One-hundred and sixteen patients were included, with a mean HI of 5.8 ± 3.6 and a mean CI of 35.8 ± 18.0%. ST was significantly related to malformation indexes, being patients with absence of ST those showing the lowest HI (p = 0.048) and CI (p = 0.002). Right-sided ST was significantly related to the CC classification (p = 0.0001), and the tricuspid/mitral annulus width ratio was significantly lower among these patients (absence 0.98 ± 0.15, left-sided 0.91 ± 0.10, right-sided 0.80 ± 0.15, p < 0.0001). A significant inverse relationship between ST degrees and the tricuspid/mitral ratio was also identified (r = -0.47, p < 0.0001).

CONCLUSIONS

We identified a significant relationship between ST and both chest malformation and CC indexes; the absence of ST being identified as a marker of an overall more benign phenotype.

TYPE OF STUDY

Study of diagnostic test.

LEVEL OF EVIDENCE

Level II.

Impact of pectus excavatum on cardiac morphology and function according to the site of maximum compression: effect of physical exertion and respiratory cycle

Aims

Previous studies have demonstrated diverse cardiac manifestations in patients with pectus excavatum (PEX), although mostly addressing morphological or physiological impact as separate findings. Using multimodality imaging, we evaluated the impact of PEX on cardiac morphology and function according to the site of maximum compression, and the effect of exertion and breathing.

Methods and results

All patients underwent chest computed tomography, cardiac magnetic resonance (CMR), and stress echocardiography (echo) in order to establish surgical candidacy. We evaluated diastolic function and trans-tricuspid gradient during stress (echo); and systolic function and respiratory-related septal wall motion abnormalities (CMR). Patients were classified according to the site of cardiac compression as type 0 (without cardiac compression); type 1 (right ventricle); and type 2 [right ventricle and atrioventricular (AV) groove]. Fifty-nine patients underwent multimodality imaging, with a mean age of 19.5 ± 5.9 years. Compared with a sex and age matched control group, peak exercise capacity was lower in patients with PEX (8.4 ± 2.0 METs vs. 15.1 ± 4.6 METs, P &lt; 0.0001). At stress, significant differences were found between groups regarding left ventricular E/A (P = 0.004) and e/a ratio (P = 0.005), right ventricular E/A ratio (P = 0.03), and trans-tricuspid gradient (P = 0.001). At CMR, only 9 (15%) patients with PEX had normal septal motion, whereas 17 (29%) had septal flattening during inspiration. Septal motion abnormalities were significantly related to the cardiac compression classification (P &lt; 0.0001).

Conclusions

The present study demonstrated that patients with PEX, particularly those with compression affecting the right ventricle and AV groove, manifest diverse cardiac abnormalities that are mostly related to exertion, inspiration, and diastolic function.