The cardiothoracic ratio: a neglected preoperative risk-stratified method for patients with rheumatic heart disease undergoing valve replacement surgery

Utility of Recipient Cardiothoracic Ratio in Predicting Delayed Chest Closure after Heart Transplantation

BACKGROUND

 Predicted cardiac mass (PCM) has been well validated for size matching donor hearts to heart transplantation recipients. We hypothesized that cardiothoracic ratio (CTR) could be reflective of recipient-specific limits of oversizing, and sought to determine the utility of donor to recipient PCM ratio (PCMR) and CTR in predicting delayed chest closure after heart transplantation.

METHODS

 A retrospective review of prospectively collected data on 38 consecutive heart transplantations performed at our institution from 2017 to 2020 was performed. Donor and recipient PCM were estimated using Multi-Ethnic Study of Atherosclerosis predictive models. Receiver operating characteristic analysis was performed to determine the discriminatory power of the ratio of PCMR to CTR in predicting delayed sternal closure.

RESULTS

 Of the 38 patients, 71.1% (27/38) were male and the median age at transplantation was 58 (interquartile range [IQR]: 47-62) years. Ischemic cardiomyopathy was present in 31.6% of recipients (12/38). Median recipient CTR was 0.63 [IQR: 0.59-0.66]. Median donor to recipient PCMR was 1.07 [IQR: 0.96-1.19], which indicated 7% oversizing. Thirteen out of 38 (34.2%) underwent delayed sternal closure. Primary graft dysfunction occurred in 15.8% (6/38). PCMR/CTR showed good discriminatory power in predicting delayed sternal closure [area under the curve: 80.4% (65.3-95.6%)]. PCMR/CTR cut-off of 1.7 offered the best trade-off between the sensitivity (69.6%) and specificity (91.7%).

CONCLUSION

 CTR could be helpful in guiding the recipient-specific extent of oversizing donor hearts. Maintaining the ratio of PCMR to CTR below 1.7 could avoid excessive oversizing of the donor heart.

Predictive Role of Preoperative Nutritional Status on Early Postoperative Outcomes in Different-Aged Patients Undergoing Heart Valve Surgery

OBJECTIVES

The authors sought to elucidate the role and predictive effects of preoperative nutritional status on postoperative outcomes across different age groups undergoing heart valve surgery.

DESIGN

A retrospective study with intergroup comparison, receiver operating characteristic curve analysis, and logistic regression analysis.

SETTING

A hospital affiliated with a medical university.

PARTICIPANTS

Three thousand nine hundred five patients undergoing heart valve surgery between October 2016 and December 2020.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Patients were categorized into 3 age subgroups: young (aged 18-44 years), middle-aged (aged 45-59 years), and older (aged ≥60 years) adults. The Nutritional Risk Index (NRI), Prognostic Nutritional Index, and Controlling Nutritional Status scores were evaluated. Young adults with an NRI <99 experienced a significantly higher rate of prolonged intensive care unit stay (28.3% v 4.1%, p < 0.001), with a relative risk of 4.58 (95% CI: 2.04-10.27). Similarly, young adults with an NRI <97 had a significantly increased occurrence of mortality within 30 days after surgery (6.3% v 0.2%, p < 0.001), with a relative risk of 41.11 (95% CI: 3.19-529.48).

CONCLUSIONS

In patients who undergo heart valve surgery, early postoperative outcomes can be influenced by nutritional status before the surgery. In the young-adult group, NRI <99 and NRI <97 effectively could predict prolonged intensive care unit stay and 30-day mortality, respectively.

The Performance of a Deep Learning-Based Automatic Measurement Model for Measuring the Cardiothoracic Ratio on Chest Radiographs

OBJECTIVE

Prior studies on models based on deep learning (DL) and measuring the cardiothoracic ratio (CTR) on chest radiographs have lacked rigorous agreement analyses with radiologists or reader tests. We validated the performance of a commercially available DL-based CTR measurement model with various thoracic pathologies, and performed agreement analyses with thoracic radiologists and reader tests using a probabilistic-based reference.

MATERIALS AND METHODS

This study included 160 posteroanterior view chest radiographs (no lung or pleural abnormalities, pneumothorax, pleural effusion, consolidation, and n = 40 in each category) to externally test a DL-based CTR measurement model. To assess the agreement between the model and experts, intraclass or interclass correlation coefficients (ICCs) were compared between the model and two thoracic radiologists. In the reader tests with a probabilistic-based reference standard (Dawid-Skene consensus), we compared diagnostic measures-including sensitivity and negative predictive value (NPV)-for cardiomegaly between the model and five other radiologists using the non-inferiority test.

RESULTS

For the 160 chest radiographs, the model measured a median CTR of 0.521 (interquartile range, 0.446-0.59) and a mean CTR of 0.522 ± 0.095. The ICC between the two thoracic radiologists and between the model and two thoracic radiologists was not significantly different (0.972 versus 0.959, p = 0.192), even across various pathologies (all p-values > 0.05). The model showed non-inferior diagnostic performance, including sensitivity (96.3% versus 97.8%) and NPV (95.6% versus 97.4%) (p < 0.001 in both), compared with the radiologists for all 160 chest radiographs. However, it showed inferior sensitivity in chest radiographs with consolidation (95.5% versus 99.9%; p = 0.082) and NPV in chest radiographs with pleural effusion (92.9% versus 94.6%; p = 0.079) and consolidation (94.1% versus 98.7%; p = 0.173).

CONCLUSION

While the sensitivity and NPV of this model for diagnosing cardiomegaly in chest radiographs with consolidation or pleural effusion were not as high as those of the radiologists, it demonstrated good agreement with the thoracic radiologists in measuring the CTR across various pathologies.

Radiological Cardiothoracic Ratio as a Potential Marker of Left Ventricular Hypertrophy Assessed by Echocardiography

The aim of the study was to verify the usefulness of the radiological cardiothoracic ratio as a potential marker of left ventricular hypertrophy assessed by echocardiography. The study included 96 patients (mean age: 49.52 ± 9.64 years). Chest radiograph in the PA projection and echocardiography were performed. In CR the measurement of the cardiothoracic ratio (CTR) was performed. Assuming CTR > 0.50, heart silhouette enlargement was diagnosed. In echocardiography, four types of left ventricular geometry were assessed: normal geometry (NG), concentric remodeling (CR), concentric hypertrophy (CH), and eccentric hypertrophy (EH). It was shown that patients with an enlarged heart silhouette were characterized by a significantly more frequent occurrence of left ventricular hypertrophy (LVH) on echocardiography than patients with a nonenlarged heart silhouette. In the subgroup of patients with LVH compared to the subgroup of patients with normal left ventricular geometry, CTR values are statistically significantly higher, and heart silhouette enlargement is significantly more frequent. The criterion “CTR > 0.49” estimates LVH with a sensitivity of 93.3% and specificity of 82.7%, which translates into a high accuracy of 84.4%. By analyzing the prediction of left ventricular geometry types, high accuracy of CH prediction was obtained using the “CTR > 0.49” criterion of 80.2% (with a high sensitivity of 84.0% and a satisfactory specificity of 60.0%) and a high accuracy of EH prediction using the “CTR > 0.52” criterion of 71.9% (with high sensitivity 80.5% and low specificity 36.8%), as well as low CR prediction accuracy of only 57.3% (with low sensitivity 36.7%, even if high specificity 78.7%). In summary, the radiological cardiothoracic ratio may be a moderate marker of left ventricular hypertrophy assessed according to standard echocardiographic criteria, provided that its cut-off point is standardized in each population of subjects.

Risk Factors for Aortic Regurgitation Progression After Repair of Sinus of Valsalva Aneurysm

BACKGROUND

The main treatment for a ruptured sinus of Valsalva aneurysm (SVA) is surgical repair. Postoperative progression of aortic regurgitation (AR) following SVA repair increases the risk of reoperation, which decreases the long-term survival. Thus, identifying the risk factors for postoperative AR progression is of great significance.

METHODS

Adult patients who were diagnosed with ruptured SVA and underwent surgical repair at the current centre were reviewed. Necessary data in the institutional database were extracted. The perioperative and follow-up assessments of the aortic valve by transthoracic echocardiography were also obtained. The aortic regurgitation progression was grouped into three categories: newly developing, recurrence, and worsening. Sixteen (16) variables were screened to identify potential risk factors by univariate logistic regression analysis or Chi-squared test. Variables with p-values <0.1 were further analysed by multivariate logistic regression models to find independent risk factors.

RESULTS

A total of 198 consecutive patients from June 2006 to January 2018 were included. The overall incidence of postoperative AR progression was 19.2% (38 of 198). After the univariate analysis, SVA originating from the right coronary sinus, coexisting with ventricular septal defect, larger diameter of aortic annulus, and larger cardiothoracic ratio were screened as potential risk factors. Multivariate analysis indicated that coexisting with a ventricular septal defect (VSD) (OR, 2.82; 95% CI, 1.217-6.532; p=0.016) and larger cardiothoracic ratio (OR, 1.061; 95% CI, 1.001-1.124; p=0.047) were independent risk factors for postoperative AR progression.

CONCLUSIONS

To prevent postoperative AR progression after surgical repair, more careful inspection and appropriate surgical techniques are necessary for patients coexisting with VSD or with a larger cardiothoracic ratio.

Radiological Cardiothoracic Ratio in Evidence-Based Medicine

The cardiothoracic ratio (CTR), expressing the relationship between the size of the heart and the transverse dimension of the chest measured on a chest PA radiograph, is a commonly used parameter in the assessment of cardiomegaly with a cut-off value of 0.5. A value of >0.5 should be interpreted as enlargement of the heart. The following review describes the current state of available knowledge in terms of contentious issues, limitations and useful aspects regarding the CTR. The review was carried out on the basis of an analysis of scientific articles available in the PubMed database, searched for using the following keywords: “CTR”, “cardiothoracic ratio”, “cardiopulmonary ratio”, “cardiopulmonary index”, and “heart-lung ratio”. According to the accumulated knowledge, the CTR can still be used as an important parameter that can be easily determined in establishing enlargement of the heart. However, an increased CTR does not directly relate to heart function. In the era following the development of diagnostic methods such as computed tomography, magnetic resonance imaging, and ultrasonography, CTR modifications based on these methods are used with varying clinical usefulness. It is important to consider the definition of the CTR and remember to base measurements on PA radiographs, as attempts to mark it in other projections face many limitations.