Cardiovascular MRI assessment of pectus excavatum in pediatric patients and postoperative simulation using vacuum bell.

BACKGROUND: The sternal lift by Vacuum Bell (VB) is effective, as largely demonstrated by its intraoperative use during surgical procedure to elevate the sternum during the Nuss procedure routinely. Indeed, the thoracic remodelling during VB application is comparable to post-surgical scenario, and suitable to compare cardiovascular parameters of the two different thoracic configurations immediately. OBJECTIVE: We would quantify and correlate preoperative parameters which determine the severity of the pectus excavatum (PE), and the cardiovascular effects at the baseline. Than we would assess the cardiovascular changes during VB positioning, mimicking the immediate, temporary effect of Pectus-correction. MATERIALS AND METHODS: We included 26 consecutive patients (mean age is 13,3 +/- 2,2 years) symptomatic and non, with a previous clinical diagnosis of PE. CMR was performed before and during application of VB, using the same imaging protocol. In both conditions, we measured thoracic indexes, and cardiac function as well as flow through main vessels. RESULTS: Mean expiratory Haller Index (HI) was 5,4 (+/-1,4 SD; normal <3). During VB application, all patients showed improvement in the main morphologic parameters of the thorax (mean expiratory HI = 4,7 (+/-1,6 SD, delta -13%, P = 0,01). During VB application, a minimal but not significant increase of Right Ventricle End Diastolic Volume (RVEDVi) (delta +4,6%, P = 0,12), and Right Ventricle Ejection Fraction (RVEF) (delta +1,2%, P = 0,2) was observed. CONCLUSION: In adolescents affected by PE, cardiacMRI (CMR) demonstrates normal values of biventricular volume and systolic function. During VB application, beside significative improvements in chest wall anatomy, CMR shows a minimal positive variation in right ventricle volume and function. A minority of patients showed some degree of diastolic dysfunction at baseline, unchanged after VB application, with possible correlation between valve inflow and sternal impingement.

Tricuspid annular plane systolic excursion for the assessment of ventricular function in adults operated on with mustard procedure for complete transposition of the great arteries.

BACKGROUND: In adult patients with d-transposition of the great arteries after atrial switch operation, dysfunction of the systemic right ventricle (RV) is a well-known complication. Echocardiographic variables may provide adequate estimation of subpulmonary RV function, but their applicability to the subaortic RV is not straightforward. We evaluate the concordance between tricuspid annular plane systolic excursion (TAPSE) and magnetic resonance imaging-derived ejection fraction of the RV (MRI-RVEF) in these patients. METHODS: Patients were recruited from those evaluated at the adult congenital clinic of our department between 2010 and 2012. All patients who had an echocardiographic assessment within 6 months of their MRI examination were selected. Patients clinically unstable, not in sinus rhythm, with a prosthetic systemic atrioventricular valve, permanent pacemaker, or more than moderate systemic atrioventricular valve regurgitation were excluded. RESULTS: Eighteen Mustard-operated patients aged 22 ± 3.7 years were studied. The mean values of TAPSE and RVEF were 13.22 ± 1.7 mm and 49.7 ± 6%, respectively. TAPSE and RVEF were normal in 1 (5.5%) and 10 (55.5%) patients, respectively. Seventeen (94.4%) patients showed reduced TAPSE (12.9 ± 1.3 mm): RVEF was reduced in eight (47%) of these subjects, and normal in nine (53%). In patients with normal RVEF, both the MRI-RV end-diastolic and the MRI-RV end-systolic volumes were significantly lower than in patients with reduced RVEF. There were no other statistically significant differences between these patients. No correlation was found between TAPSE and both the MRI-RV end-diastolic and the end-systolic volumes. Globally, agreement between TAPSE and RVEF was slight (K = 0.09 ± 0.089). CONCLUSIONS: Our results indicate that in these patients TAPSE is not a useful measure of RV function.