Quantification of left-to-right shunt through patent ductus arteriosus by colour Doppler in children admitted for a device closure.

PURPOSE: Our animal model suggests that quantification of ductal flow from colour Doppler pixels is possible. We aimed to clarify whether this method can be used to determine a clinically significant ductal shunt in children. METHODS: We retrospectively quantified ductal flow from saved images from 20 children who had been admitted for device occlusion of patent ductus arteriosus. Colour Doppler images over the main stem of the pulmonary artery were obtained in longitudinal cross-sections. The colour pixel percentages during diastole, representing ductal flow, were correlated with the documented shunt, measured invasively according to Fick's principle. RESULTS: The ratio of pulmonary to systemic flow correlated best with the sum of the percentages of green colour pixels (r = 0.73, r2 = 0.54, p < 0.001). When the shunt was 1.5:1 or more, 12 out of 13 infants had 50% or more of the region of interest covered with green pixels--sensitivity 92%, specificity 71%. The correlation between ductal diameter and pulmonary-to-systemic flow ratio was less significant (r = 0.6, r2 = 0.37, p < 0.03). CONCLUSIONS: We conclude that clinically significant shunts with pulmonary-to-systemic flow ratio over 1.5 can be diagnosed with this method where neither the size of the patient nor echocardiographic settings seem to be critical. The method could be used to provide an objective indication for ductal closure, but further prospective studies in children are needed to verify the power of the method.

Quantification of left to right shunt in patent ductus arteriosus by color Doppler.

Ultrasound is a reliable tool to diagnose patent ductus arteriosus in premature infants but no reliable noninvasive method exists to quantify ductal flow. The aim of this study was to quantify the size of the shunt via persistent ductus arteriosus from pixel counts in color Doppler flow images. A cotton band was placed around the ductus arteriosus of newborn lambs to adjust the magnitude of flow. For flow measurements, ultrasonic transit time flow probes were applied around the ascending aorta and ductus arteriosus. Twenty-four different flow states were attained in four newborn lambs. An Acuson Sequoia scanner equipped with a 7 MHz transducer was used to register Doppler data and images with maximal color distribution during diastole in the pulmonary artery longitudinal sections (PALS). Each image-pixel was matched with the color velocity bar and the pixels were assigned to the corresponding flow velocity. The total area showing color relative to the area of the PALS correlated well with the amount of ductal flow (r = 0.87, r(2) = 0.75, p < 0.001). When Qp/Qs was >1.4:1, more than 40% of the area in PALS in diastole exhibited color information. Similarly, the color pixel velocities squared correlated with the size of the shunt. Quantification of the percentage of pixels in a color Doppler registration via a computer-based analysis shows a high correlation with the size of ductal shunting.

Acute decrease of coronary flow after indomethacin delivery in newborn lambs.

AIM: To document the effects of indomethacin (IND) on coronary flow. METHODS: We studied nine premature lambs during the first day of life. The gestational age varied between 132 and 134 days (term 145 days) and weight 3.1-4.7 kg. Coronary flow velocities were recorded with an intracoronary Doppler guide wire in the proximal left anterior descending coronary artery (LAD). Average peak flow velocity was measured before, during and after an intravenous IND injection of 0.2 mg per kilogram of body weight. RESULTS: IND increased systemic blood pressure (p < 0.05) and rate pressure product (RPP; p < 0.05) indicating that IND increased cardiac workload. IND decreased coronary average peak flow velocity in all lambs (p < 0.05). The maximal fall in coronary velocity appeared after 3 min (range 1-7 min) and was regained 10 min (range 4-53 min) after the drug delivery. The maximal reduction of coronary average peak flow velocity was 52% (median 26). The recovery time was directly related to the maximal reduction of the coronary average peak flow velocity (R = 0.91, R(2) 0.84, p < 0.002). CONCLUSION: Coronary flow velocity decreased markedly in premature born lambs given a bolus dose of IND.

Heart transplantation across the antibodies against HLA and ABO.

We have intentionally performed heart transplantation in a 5-year-old child, despite the most unfavourable risk factors for patient survival; the presence of high level of antibodies against donor's human leucocyte antigen (HLA) class I/II and blood group antigens. Pretransplant treatment by mycophenolate mofetil, prednisolone, tacrolimus, intravenous immunoglobulin, rituximab, protein-A immunoadsorption (IA) and plasma exchange reduced antibody titres against the donor's lymphocytes from 128 to 16 and against the donor's blood group antigen from 256 to 0. The patient was urgently transplanted with a heart from an ABO incompatible donor (A(1) to O). A standard triple-drug immunosuppressive protocol was used. No hyperacute rejection was seen. Antibodies against the donor's HLA antigens remained at a low level despite three acute rejections. Rising anti-A(1) blood group antibodies preceded the second rejection and were reduced by two blood group-specific IAs and remained at a low level. The patient is doing well despite the persistence of donor-reactive antibodies.