Search

Biplane Area-Length (AL) method by left ventriculography (LVG) has been widely adopted as a standard method to estimate left ventricular volume. However, we have experienced difficulties in adopting the value by AL method for the children with Tetralogy of Fallot (TOF) due to the discrepancy among volumetric modalities. This study validated some limitations of AL method, considering the basic principles of its formulation. A single center retrospective cohort study was conducted for 1 year. The confirmed 22 cases with repaired TOF at our hospital were enrolled. The clinical characteristics, some cardiac MRI analyses, and all the cardiac catheterization studies were collected. Angiographic data were compared with historic cohorts of Kawasaki disease without any coronary artery lesions by using AL method. Cardiac MRI analyses of ten TOF patients were additionally available. LVG studies showed that the length of the long axis on anteroposterior view (AP) was not equal to that on lateral view (LT) due to anatomically apical elevation in TOF, followed by a significant difference found in the sagittal lengths of the LV long axis between AP and LT (P = 0.003). Because the difference critically affected the formula depending on biplane AL method, the calculated LVEDV of TOF group appeared overestimated, compared with the control group (TOF vs control group: 119.5% ± 6.3% vs 96.4 ± 3.5% of Normal, P = 0.006). Available cardiac MRI analyses of some patients in TOF group revealed 55% increase of LVEDV by AL method (angiocardiography 116 ± 7.0 vs CMR 75 ± 3.7 ml/m 2 , P = 0.0025). A pitfall exists when applying biplane AL method to measure LV volume especially for TOF patients, because the long axis on AP view is not always identical to that on LT view., (© 2022. Springer Japan KK, part of Springer Nature.)

Progressive aortic root dilation and stiffening have been reported in patients with tetralogy of Fallot (TOF), even after repair. However, the implications of such aortic dilation and stiffening have not been fully assessed. A stiff aorta has a negative effect on the coronary circulation. 15 patients with TOF after repair were enrolled in this study. Using a left ventriculogram and pressure waveform recorded by a pressure sensor-mounted catheter, we analyzed the diameter and distensibility of the ascending and descending aorta. We also calculated the subendocardial viability ratio (SEVR), which measures the cardiac blood supply-workload balance. These values were compared with those in one-to-one age-matched controls. Moreover, the correlation between the diameter ratio (aortic diameter of the patient/aortic diameter of the matched control subject) and the distensibility ratio (distensibility of the patient/distensibility of the matched control subject) was analyzed. The mean age of patients was 3.9 ± 1.6 years. In patients with TOF, the indexed diameter was larger (0.20 ± 0.02 vs. 0.15 ± 0.02 mm/cm, p < 0.0001) and the distensibility was lower (5.1 ± 2.2 vs. 7.7 ± 2.0 cm 2  dynes -1  10 -6 , p = 0.0009) in the ascending aorta than in control subjects. There was no difference in the SEVR between patients and control subjects. The distensibility ratio was significantly negatively correlated with the indexed diameter ratio in the ascending aorta (r 2  = 0.35, p = 0.019). Regardless of the aortic stiffening, the cardiac blood supply-workload balance was maintained. We speculate that the aortic root dilation might be a mechanism to functionally complement aortic stiffness in patients with TOF.