Improvement of heart function after balloon dilation of congenital valvar aortic stenosis: a pilot study with ultrasound tissue Doppler and strain rate imaging

The aim was to investigate the effects of balloon dilation of congenital valvar aortic (Ao) stenosis on heart function with conventional and with new echocardiographic techniques. Nine patients, preballoon and 1 to 4 d postballoon dilation of Ao-valve, were included in the study. Assessment of heart function was made by using conventional echo/Doppler, tissue Doppler imaging (TDI) and strain rate imaging (SRI). Mean (and standard deviation) of posttreatment drop of aortic valve pressure gradient was 34.1 (sd 14.0) mmHg, p < 0.01. Conventional echo/Doppler end-diastolic left ventricular posterior wall (LVPW) thickness and interventricular septum (IVS) thickness did not change significantly. Mean change of LV fractional shortening (FS) was -5.2 (sd 3.2)%, p < 0.01. The observed changes of FS did not significantly correlate to the magnitude of pressure gradient changes. Changes of TDI and SRI parameters indicated that an increase in absolute value is observed in most cases, but correlation to pressure gradient change remains poor, with a few exceptions, both in LV free wall (LVFW) and IVS. Data from IVS are more consistent than of LVFW. It is concluded that the global functional parameter FS assessed by conventional echo/Doppler has diagnostic value for the assessment of (improved) heart function already shortly after intervention, when compared with the pretreatment value. Local parameters from the new echographic techniques show less significant short-term effects attributable to the intervention. Improvement of the precision of SRI measurements is needed. A larger study is indicated to fully investigate the expected potentials of TDI and SRI for the assessment of local improvement of heart function early after intervention, as well as for revealing eventual late effects on these functional parameters.