CARDIOVASCULAR JOURNAL OF AFRICA • Volume 34, No 1, January–April 2023 AFRICA 11 cycle in which the cardiac volume was smallest. Papillary muscles were included in the cavity for the tracing. Quantitative determination of LVEF was calculated using left ventricular end-diastolic volume (LVEDV) and left ventricular end-systolic volume (LVESV) estimates as follows: LVEF = LVEDV – LVESV ______________ LVEDV according to the guidelines.10,11 Both Simpson’s method and the area–length method were applied on CMR. On short-axis view (Fig. 3), the outline of the endocardial border of the left ventricle was traced manually on all slices of each phase by one experienced cardiologist or one radiologist using standard software (Mass Research software, version V2013-EXP, Leiden University Medical Center). Volumes were computed by Simpson’s method of disk summation where the sum of the cross-sectional areas was multiplied by the slice thickness. On CMR, the left ventricle was considered dilated for a LVEDVCMR > 246 ml. Phase-contrast cardiac magnetic resonance (PC-CMR) images were also acquired in order to compute the stroke volume. On PC images, the lumen of the ascending aorta was segmented automatically and corrected manually throughout the cardiac cycle (Fig. 4). Blood flow within the vessel has been computed by summing the regions of interest.12 The average flow velocity (cm/s) was multiplied by the area of the vessel (cm²) to obtain flow (ml/s) at each point. Stroke volume (ml) was obtained by dividing cardiac output (l/min) by heart rate (bpm).13 AR grading was defined as follows: mild, AR volumes < 30 ml (regurgitation fraction < 30%); moderate, AR volumes 30–59 ml (regurgitation fraction 30–49%); severe, AR volumes ≥ 60 ml (regurgitation fraction ≥ 50 %).6 Statistical analysis The statistical analysis was performed using SPSS for Windows (SPSS version 17, Chicago, Illinois). Continuous variables are expressed as means ± standard deviations. Categorical variables are expressed as percentages. Differences between CMR and TTE were compared using the Student’s t-test. Pearson’s correlation coefficients were calculated by linear regression for continuous variables. A p-value < 0.05 was considered significant. The intraclass correlation coefficient (ICC) for a two-way random-effects model with absolute agreement was calculated to assess the concordance between TTE andCMR for quantification of AR severity. ICCs were categorised as excellent (ICC ≥ 0.75), good (ICC 0.6–0.74), fair (ICC 0.4–0.59) or poor (ICC < 0.4).14,15 Results From May 2009 to June 2020, 198 patients had both a CMR and TTE showing AR. After checking the delay between both examinations (< 3 months) and after exclusion of patients with AF and those with other significant valvular disease and primary cardiomyopathy, AR was the sole and main diagnosis in 50 (25.2%) patients, who constituted our population. The clinical data are summarised in Table 1. Out of the 50 patients, 13 (26%) had bicuspid aortic valve and eight (16%) had aortic valvular prosthesis. The mean time between TTE and CMR was 44.2 ± 19.5 days. Regarding echocardiography, the PISA method was possible in 19 patients (38%). According to this method, seven patients (14%) had mild AR, eight (16%) had moderate AR and four (8%) had severe AR. The EDVDA measurement was used in 12 patients (24%) and severe AR was detected in eight patients (16%). The vena contracta was measured in 28 patients (56%) and we classified 10 patients (20%) with severe AR, two (4%) with mild AR and 16 (36%) with moderate AR. PHT was measured in 21 patients (42%) and nine (18%) had mild AR, none had severe AR and 12 (24%) had moderate AR. Fig. 3. Basal and mid-ventricular short-axis view with diastolic and systolic contours. Fig. 4. Phase-contrast ciné CMR in the transverse plane at the level of the pulmonary artery bifurcation. A: magnitude and phase images. B: flow curve in the ascending aorta with holodiastolic retrograde flow. A B
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