Aims: To evaluate the method of catheterization occlusion of the atrial septal defect (ASD) by the Amplatzer method. To find out differences between catheterization and surgical occlusion in the efficiency, functional results and occurrence of complications as well as the cost. Methods: The centrally localized defect of the atrium septum of the secundum type was closed by theAmplatzer occluders in 55 selected patients in the years 1998 to 2002. Themedian age of the patients was 8.5 years (6.2 - 13.5, 25 percentile/75 percentile). The mean body weight was 25.8 kg (20.3 - 51.9). The diameter of the atrium septum defect was 12.0 mm (10 - 13.9); it was in the range of 5 to 22 mm. The mean period of observation was 372 days(108 - 750) with the range of two days to 3.7 years. The results were compared with 153 patients, whose ASD of the secundum type was occluded by surgery in the same period of time. Results: The occluder was successfully implanted in all 55 patients, where the decision of this intervention was accepted. Immediately after the ASD occlusion there was a significant reduction of left-right shunt from 38 %Qp (24 - 48) to two %Qp (P < 0.001), the decrease of lung flow rate was from 5.64 l/min/m2 BSA (4.7 - 6.7) to 4.52 l/min/m2 BSA (3.8 - 5.2) (P < 0.01), a decrease of pressure in the right atrium was from 6.1 ± 1.6 torr to 5.5 ± 1.7 torr (P < 0.005), an increase of diastolic pressure from 8.0 (7.0 - 10.0) torr to 10 torr (8.8 - 12.0) and the mean pressure in pulmonary artery was from 14.0 torr (12.6 - 16.0) to 15.0 torr (13.0 - 18.0) (P < 0.001) and an increase of the mean pressure in the impacted pulmonary artery against the pressure in the left atrium before the occlusion was from 7.6 ± 2.1 torr to 9.7 ± 2.8 torr (P < 0.001). The heart index significantly increased after the occlusion from 3.7 ± 1.0 l/min/m2 BSA to 4.4 ± 1.2 l/min/m2 BSA (P < 0.001) and the mean systemic pressure significantly increased from 71 torr (66 - 81) to 88 torr (80 - 95) (P < 0.001). The significantly increased right-heart compartments were significantly decreased as early as after 24 hours after the catheterization occlusion. The echocardiography-measured area of the right atrium decreased from 151 ± 25% of normal value to 119 ± 22% of normal value (P < 0.001) as well as the short axis of the right ventricle from 218%(193 - 231) of normal value to 189% (155 - 203) of normal value (P < 0.001). The mean values of total functional capacity of the lungs was normal during all measurements: two and a half months after the occlusion they slightly increased from 101% ± 18% of normal values to 106% ± 13% of normal values (P < 0.05) only to return to the original value during further observation. In spite of the differences in the catheterization and surgical occlusion the authors did not find any significant deviations from pulmonarymechanics after both kinds of therapy measured before the intervention and in the period of one to two years afterwards. Insignificant complications were detected in four (7%) patients after the catheterization occlusion. Their incidence was lower than in the group of patients after the surgery (21%, P < 0.05). No residual shunt was found in 54 from 55 patients (98%), in one girl there was a completely insignificant residual shunt through the center of the occluder 122 days after the intervention. There was a zero mortality in both the catheterization and the surgical occlusion. The catheterization occlusion was significantly more expensive [272 ± 16 thousand Czech crowns against 125 ± 18 thousand crowns in the surgical occlusion (P < 0.001)]. The high cost of the catheterization intervention wasmainlycausedbytheprice oftheoccluder,whichreached198thousandcrowns; it was not compensated by the substantially lower cost of other components [13.1 (12.6 - 13.4) thousand crowns against 44.3 (40.2 - 57.7) thousand crowns (P< 0.001)] connected with a significantly shorter period of hospitalization occlusion of three (3 - 3) versus 8 (7 - 9) days after the heart surgery (P < 0.001). Conclusions: The catheterization occlusion of the atrial septal defect by the Amplatzer method proved to be efficient and safe. It decreased the operation load, pain and scarring. It also decreased the number and significance of complications after the intervention. The method is still expensive, since the low cost of hospitalization and working force is unable to compensate the high cost of the material used. In the indicated patients the Amplatzer catheterization method for the atrium septum occlusion is the method of choice.

        Key words: defect of atrium septum, catheterization occlusion, Amplatzer occluder, cardiosurgery