Comparison and Agreement between Cardiovascular Computed Tomography-Derived Mid-Diastolic and End-Diastolic Ventricular Volume in Patients with Congenital Heart Disease

Prospective electrocardiogram (ECG)-triggered cardiovascular computed tomography (CCT) is primarily utilized for anatomical information in congenital heart disease (CHD) and has not been utilized for calculation of the end-diastolic volume (EDV); however, the mid-diastolic volume (MDV) may be measured. The objective of this study was to evaluate the feasibility and agreement between ventricular EDV and MDV. 31 retrospectively ECG-gated CCT were analyzed for the study of the 450 consecutive CCT. CCT images were processed using syngo.via with automatic contouring followed by manual adjustment of the endocardial borders of the left ventricles (LV) and right ventricles (RV) at end-diastolic and mid-diastolic phase (measured at 70% of cardiac cycle). The correlation and agreements between EDV and MDV were demonstrated using Spearman rank coefficient and intraclass correlation coefficient (ICC), respectively. Mean age ± SD was 28.8 ± 12.5 years, 19 were male (61.3%) and tetralogy of Fallot (TOF) was the most common diagnosis (58.1%), 35% (11/31) patients with a pacemaker, ICD or other such contraindication for a CMRI, 23% (7/31) with claustrophobia, and 6.5% (2/31) with developmental delay with refusal for sedation did not have a previous CMRI. The mean ± SD indexed LV EDV and LV MDV were 91.1 ± 24.5 and 84.8 ± 22.3 ml/m2, respectively. The mean ± SD indexed RV EDV and RV MDV were 136.8 ± 41 and 130.2 ± 41.5 ml/m2, respectively. EDV and MDV had a strong positive correlation and good agreement (ICC 0.92 for LV and 0.95 for RV). This agreement was preserved in a subset of patients (21) with dilated RV (indexed RV EDV z-score > 2). Intra-observer reliability (0.97 and 0.98 for LV and RV MDV, respectively) and inter-observer reliability (0.96 and 0.90 for LV and RV MDV, respectively) were excellent. In a select group of patients with CHD, measuring MDV by CCT is feasible and these values have good agreements with EDV. This may be used to derive functional data from prospectively ECG-triggered CCT studies. Further large-scale analysis is needed to determine accuracy and clinical correlation.

Identification of rapid progression of right ventricular functional measures using three-dimensional cardiac computed tomography after total surgical correction of tetralogy of Fallot

OBJECTIVE

To identify subsets of patients with tetralogy of Fallot (TOF) after total surgical correction demonstrating the rapid progression of right ventricle (RV) functional measures using cardiac computed tomography (CT) ventricular volumetry.

METHODS

Rapid or slow progression of RV functional measures was determined in 109 patients with TOF who underwent cardiac CT ventricular volumetry more than twice after total surgical correction. Patient age, body surface area, postoperative days, the time interval between the first and last cardiac CT examinations, and CT-based functional measures were evaluated using binary logistic regression to determine the predictors of the rapid progression. Receiver operating characteristic curve analysis was performed to evaluate diagnostic performance of the potential predictors.

RESULTS

The rapid progression of indexed RV end-systolic volume (ESV) (≥2.7 mL/m²/year) and indexed RV end-diastolic volume (≥0.9 mL/m²/year) could be predicted by RV ejection fraction (EF) at the last cardiac CT with an odds ratio of 1.340 (95 % confidence interval [CI], 1.122-1.600; p = 0.001) and age at the last cardiac CT with an odds ratio of 8.255 (95 % CI, 1.531-44.513; p = 0.014), respectively. RV EF at the last cardiac CT showed the highest diagnostic performance (area under the curve = 0.799; p < 0.002) for the rapid progression of indexed RV ESV.

CONCLUSION

Cardiac CT ventricular volumetry can be used to identify patients demonstrating the rapid progression of RV functional measures after total surgical correction of TOF and follow-up imaging protocols can be individually optimized based on initial progression rate.

Pulmonary valve replacement may not restore ventricular volume and functional status in patients with pulmonary regurgitation after late tetralogy of Fallot repair

OBJECTIVES

Clinically, tetralogy of Fallot (TOF) patients who underwent repair late (older than 2 years) appears to have worse outcomes after pulmonary valve replacement than patients who underwent repair early. We proceeded to review the clinical features of late-repaired TOF patients who required pulmonary valve replacement.

METHODS

Fifty patients who underwent pulmonary valve replacement after TOF repair over the age of 2 years from 2000 to 2018 were retrospectively reviewed. Pre- and postoperative cardiac magnetic resonance imaging, cardiopulmonary exercise tests, and cardiac catheterization were analysed.

RESULTS

The median age of patients at the time of TOF repair and pulmonary valve replacement was 3.6 and 23.4 years, respectively. The median interval from TOF repair to pulmonary valve replacement was 20.5 years. Cardiac magnetic resonance imaging and cardiopulmonary exercise tests were performed at a median of 5.9 and 3.7 years after pulmonary valve replacement, respectively. Cardiac magnetic resonance revealed that there were significant changes in the indexed values of the right ventricle end-diastolic volume (164.7-106.9 ml/m2, P < 0.001), end-systolic volume (101.4-64.9 ml/m2, P < 0.001), stroke volume (66.8-48.0 ml/m2, P = 0.007) and cardiac output (5.1-3.6 l/m2, P = 0.040). Twenty-eight percentage of patients achieved normalization of the right ventricular volume after pulmonary valve replacement. In the exercise test, the maximum rate of oxygen consumption (72.5-69.5%) and oxygen pulse (95.0-83.0%) changed without statistical significance.

CONCLUSIONS

Although pulmonary valve replacement after late TOF correction improves right ventricular volume status, only a minority of patients achieve normalization of right ventricular end systolic volume and a normal functional status.

Noninvasive stratification of postinfarction rats based on the degree of cardiac dysfunction using magnetic resonance imaging and echocardiography

The myocardial infarction (MI) rat model plays a crucial role in modern cardiovascular research, but the inherent heterogeneity of this model represents a challenge. We sought to identify subgroups among the post-MI rats and establish simple noninvasive stratification protocols for such subgroups. Six weeks after induction of MI, 49 rats underwent noninvasive examinations using magnetic resonance imaging (MRI) and echocardiography. Twelve sham-operated rats served as controls. Increased end-diastolic left ventricular (LV) pressure and lung weight served as indicators for congestive heart failure (CHF). A clustering algorithm using 13 noninvasive and invasive parameters was used to identify distinct groups among the animals. The cluster analysis revealed four distinct post-MI phenotypes; two without congestion but with different degree of LV dilatation, and two with different degree of congestion and right ventricular (RV) affection. Among the MRI parameters, RV mass emerged as robust noninvasive marker of CHF with 100% specificity/sensitivity. Moreover, LV infarct size and RV ejection fraction further predicted subgroup among the non-CHF and CHF rats with excellent specificity/sensitivity. Of the echocardiography parameters, left atrial diameter predicted CHF. Moreover, LV end-diastolic diameter predicted the subgroups among the non-CHF rats. We propose two simple noninvasive schemes to stratify post-MI rats, based on the degree of heart failure; one for MRI and one for echocardiography.NEW & NOTEWORTHY In vivo phenotyping of rats is essential for robust and reliable data. Here, we present two simple noninvasive schemes for the stratification of postinfarction rats based on the degree of heart failure: one using magnetic resonance imaging and one based on echocardiography.