Four-year cardiac magnetic resonance (CMR) follow-up of patients treated with percutaneous pulmonary valve stent implantation.

OBJECTIVES: To investigate follow-up after percutaneous pulmonary valve implantation (PPVI). METHODS: Forty patients with pulmonary conduit dysfunction (males/females 24/16; 21 ± 08 years; 12 tetralogy of Fallot, 11 aortic valve disease, 17 other congenital heart disease) were planned for CMR before PPVI and repeated 7 times up to 48 months. CMR prospective results regarded: pressure gradient (PG) and regurgitation fraction (RF); end-diastolic volume, end-systolic volume, and stroke volume indexed to body surface area (EDVI, ESVI, and SVI); ejection fraction (EF) of right and left ventricles (RV, LV). A Friedman test was used for comparisons. RESULTS: Overall, PG (31 ± 06 to 16 ± 4 mmHg), RF (16 ± 17 to 0.3 ± 1 %), RVEDVI (82 ± 38 to 58 ± 12 ml/m(2)), and RVESVI (44 ± 12 to 30 ± 13 ml/m(2)) declined (p < 0.001), RVEF (49 ± 13 to 58 ± 12 %) and RVSVI (from 38 ± 14 to 40 ± 8 ml/m(2)) increased (p < 0.001), LVEDVI (67 ± 17 to 73 ± 18 ml/m(2)) and LVSVI (37 ± 11 to 43 ± 10 ml/m(2)) increased (p = 0.034 and p < 0.001). Two patients had valve fracture at 24 and 36 months and underwent surgery. One patient had stent restenosis at 24 months and underwent percutaneous retreatment. Baseline/follow-up CMR did not predict PPVI failure. CONCLUSIONS: CMR demonstrated restored pulmonary conduit function, reduced RV volumes and increased RV and LV function but did not predict valve fracture/restenosis. KEY POINTS: • A CMR 4-year follow-up after PPVI showed restored pulmonary conduit function • RV volumes were significantly reduced • RV function was significantly better in terms of increased EF and SVI • LV function was significantly better in terms of increased EDVI and SVI • Baseline/follow-up CMR did not predict three cases of PPVI failure.

A geometric index to differentiate abnormal from normal septal wall motion on cardiac MRI.

BACKGROUND: The definition of abnormal septal wall motion (SWM) is usually performed on a subjective visual assessment with cardiac MR (CMR). PURPOSE: To quantify SWM using a geometric index and to compare this index to the visual inspection in patients with or without abnormal SWM. MATERIAL AND METHODS: Cine CMR images of 100 consecutive patients were retrospectively assessed for visual evaluation of SWM and calculation of a convexity septal index (CSI) on mid-ventricular short-axis images, defined as b/a (a = minimal distance from anterior to posterior ventricular junctions; b = maximal distance from septum to a), obtained in end-systole (ES) and end-diastole (ED). Cohen κ, Bland-Altman method, Kruskall-Wallis, Mann-Whitney U, Jonckheere-Terpstra, and Spearman statistics were used to compare the two methods. RESULTS: At visual evaluation, 73 patients had normal SWM (group A), nine abnormal SWM at ES (group B), and 18 at ES and ED (group C). Median CSI for group A was significantly higher (ES = 0.23, ED = 0.25) than those for group B and C (0.10-0.15) (P < 0.001). Inter-reader reproducibility of visual evaluation was high (κ = 0.841, P < 0.001) while that for CSI was 77%. Average time for visual analysis was 3 min, for quantitative analysis 4 min. CONCLUSION: CSI is a simple and reproducible way to quantify SWM. ED CSI seems to be sensitive in detecting abnormal SWM in patients with apparently normal SWM at visual evaluation.

Segmentation of cardiac magnetic resonance cine images of single ventricle: including or excluding the accessorial ventricle?

Our aim was to compare two different approaches for segmentation of single ventricle (SV) on cardiac magnetic resonance (CMR) cine images. We retrospectively studied 30 consecutive patients (23 males; aged 27 ± 10 years) with a treated SV who underwent 1.5-T CMR using ECG-triggered axial true-FISP, HASTE and cine true-FISP sequences. We classified patients for visceroatrial situs, cardiac axis orientation, ventricular loop, morphology of SV and position of great arteries. One experienced reader segmented cine images twice, firstly including only the systemic ventricle, secondly including both systemic and accessorial ventricles. Ejection fraction (EF), indexed end-diastolic volume (EDVI), end-systolic volume (ESVI), and stroke volume (SVI) were calculated. Data were presented as medians and interquartile intervals. Four patients presented dextrocardia and one patient mesocardia. Two had situs ambiguus with asplenia and one situs ambiguus with polisplenia. Four patients showed right morphology of the SV and three levo-ventricle loop. We found 14 levo-trasposition of great arteries (TGA), 4 levo-malposition of great arteries (MGA), four dextro-MGA, two dextro-TGA, and one inverted vessel position. When segmenting only the systemic ventricle, EDVI (mL/m2) was 65 (50-91), when segmenting both ventricles 76 (58-110) (P < 0.001); ESVI (mL/m2) was 32 (24-45) and 45 (33-60), respectively (P < 0.001); EF (%) was 49 (43-57) and 33 (24-47), respectively (P = 0.003); SVI (mL/m2) was 34 (17-48) and 33 (24-47) (P = 0.070). The inclusion of the accessorial ventricle in the segmentation of SV produce a biased lower EF showing a very low contribution to the pump function.

Cardiac magnetic resonance before and after percutaneous pulmonary valve implantation.

PURPOSE: To measure the magnetic resonance (MR) artefact produced by a percutaneous pulmonary valve stent and to evaluate the changes in volumetric and functional right ventricle (RV) parameters due to percutaneous pulmonary valve implantation (PPVI). MATERIALS AND METHODS: A Melody valve was studied in vitro using clinical cardiac MR (CMR) sequences. In vivo, we analysed the CMR examinations obtained before and after PPVI of 27 consecutive patients. The echocardiography pressure gradient (PG) and catheter PG were measured. The Wilcoxon test was used for comparisons. RESULTS: In vitro, the least difference between artefact extent and actual valve size (0.1 mm) was obtained with a steady-state free precession (SSFP) sequence. In vivo, RV end-diastolic volume (ml/m(2)), end-systolic volume (ml/m(2)) and ejection fraction (%) were 79 ± 42, 43 ± 41 and 49 ± 13 before PPVI and 64 ± 21 (p = 0.054), 30 ± 14 (p = 0.021), and 54 ± 12 (p = 0.018) 6 months after PPVI, respectively. The PG and regurgitation fraction (RF) were 36 ± 15 mmHg and 14 ± 18 % before PPVI and 13 ± 15 mmHg (p < 0.001) and 2 ± 5 % (p = 0.013) after PPVI, respectively. No significant differences were found comparing the PG measured with CMR, echocardiography and catheter. CONCLUSIONS: We showed in vitro that the SSFP sequence produced the most accurate valve measurement. After PPVI, CMR showed a strong decrease of PG and RF with a significant improvement of RV function.