PMC9402386_01
Cardiac MRA, aortic arch angiography, and hemodynamic waveforms before and after volume challenge. (a) Cardiac MRA showed a crenellated arch with hypoplasia of the proximal descending thoracic aorta (z-score of -2.88), but no discrete coarctation. (b) Catheterization was performed and confirmed no arch gradient. (c) Pressure tracings document an elevated RVEDp (12 mmHg) and LVEDp (16 mmHg) but with grossly normal diastolic waveforms at the start of the case. (d) After a 500 mL bolus, RVEDp and LVEDp increased to 16 and 20 mmHg, respectively, and dramatic change in the diastolic waveforms was observed with unmasking of a "classic" square root sign and concordant RV/LV respirophasic variation.
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fig1
Cardiac MRI/MRA was ordered to further delineate anatomy, and it showed a crenellated aortic arch with mild hypoplasia of the proximal descending thoracic aorta (z-score of -2.88) with a peak velocity of 2.1 m/s, but no discrete coarctation (Figure 1(a)). Baseline hemodynamics revealed a normal cardiac index of 4.6 L/min/m2, normal PVR of 1.7 iWU, no arch gradient (Figure 1(b)), mildly elevated RVEDp (12 mmHg) and LVEDp (16 mmHg) with normal diastolic waveforms (Figure 1(c)). In addition to the rise in end-diastolic pressure, we observed a dramatic change in the diastolic waveform with unmasking of a "classic" square root sign and concordant RV/LV respirophasic variation (Figure 1(d)).