Bjarne Smevik

Acute physiological changes in canine kidneys following exposure to extracorporeal shock waves.

Nine anesthetized dogs were studied for four to five hours after administration of extracorporeal shock waves to one kidney, the contralateral organ serving as control. Urinary excretion of electrolytes, N-acetyl-beta-glucosaminidase (NAG) and kallikrein, clearances of creatinine, inulin and para-amino-hippuric acid (PAH), serum aldosterone level and plasma renin activity (PRA) were determined. On the exposed side there was a significant increase in urinary flow and urinary NAG excretion, and a significant fall in urinary osmolality. Effective renal plasma flow (ERPF) was reduced and glomerular filtration rate (GFR) unchanged, thus filtration fraction (FF) was increased. Extraction of PAH was significantly reduced compared with the control kidney. On the control side there was a significant increase in urinary flow and excretion of electrolytes, and a significant fall in urinary osmolality. GFR was increased and ERPF unchanged. FF therefore increased also on this side. The mean rise of PRA in the exposed kidney was higher than in the control kidney, the difference being not significant (p = 0.09). Our results may indicate a triggering of the renin-angiotensin system, and an effect on proximal tubular function following exposure of extracorporeal shock waves.

Transcatheter closure of atrial septal defects in the oval fossa: is the method applicable in small children?

We report our experience from 1996 through 1999, representing our initial experience with use of the Amplatzer device to close atrial septal defects. Of 46 patients taken to the catheter laboratory with the intention to close the defect, the device was permanently implanted in 40 (87%). They were aged between 1.4 and 71.8 years, with weights ranging from 7.8 to 90 kg. Both age and weight distributed into two peaks, demonstrating two different populations. The size of the devices, taking the biggest device if two were inserted, was between 9 and 30 mm. We underwent a short learning curve, but the time required for fluoroscopy, or the number of difficulties experienced, showed no connection with the size or age of the patient, nor the size of the defect itself. A suspicion that young age and small size would increase the risk and difficulties, and result in more interrupted procedures, could not be substantiated. In children no interruption was procedural. Our early experience, therefore, demonstrates that an experienced interventional team can use the Amplatzer occluder successfully to close atrial septal defects in patients of all ages and sizes, at least from 7.8 kg and up.

Catheter-based closure of atrial septal defects in the oval fossa with the Amplatzer® device in patients in their first or second year of life†

Objective: To assess feasibility, safety, and efficacy of the use of Amplatzer® occluders in closure of atrial septal defects (ASD) in children in the first 2 years of life. Background: Although scattered reports on such closure have been published, no agreement consists on the policy. Methods: In 654 patients of all ages, closure was achieved in 632 (96.6%). Data were analyzed retrospectively in all 71 children where an attempt had been made to close the ASD before their second birthday. Results: Median age and body weight were 17.2 months (range 3.9–23.8) and 10.0 kg (range 3.8–14.5), respectively. Median fluoroscopy time was 13.6 min and median device size 15 mm. Successful closure was achieved in 68 children (95.8%). Three times the procedure was aborted: in one, the device repeatedly straddled the septum; in the other two, a small left atrium restricted the movement of the left‐sided disc. One device embolized and was reimplanted after retrieval. One infant with multiple disorders died 6 days after closure from acute sepsis probably unrelated to the procedure. No other complications occurred. Only trivial shunts closing with time were registered during follow‐up. Symptomatic patients profited markedly from closure. Conclusion: The results and complications of ASD closure with the Amplatzer® device in patients in their first 2 years of life compare favorably with procedures in older patients, provided that the size of the septum and the dimensions in the left atrium are taken into consideration when selecting the size of the device.

Balloon debanding of the pulmonary artery.

Clinical balloon debanding of the pulmonary artery is reported in two patients, 6 months and 4 years of age. The band was made of Dacron, and was closed with one single polypropylene suture. This suture was subsequently ruptured with a balloon inflated within the pulmonary artery at the site of the band.Balloon debanding relieved the gradient almost completely in the two patients. No problems occurred during the procedure. In the future this may prove to be an efficient and reliable way to remove the effect of a pulmonary artery banding.

Balloon dilatation of pulmonary artery banding: Norwegian experience over more than 20 years

AIMS The purpose of this paper was to present the results of a simple modification of the suture technique for pulmonary artery banding (PAB), which allows for stepwise debanding by use of balloon catheter. METHODS AND RESULTS During the period 1985-2007, PAB operations were performed in 227 children at Rikshospitalet. Of these children, 14.5% (n = 33) were treated by balloon dilatation of the PAB. Nine were treated twice. The intention of the procedure was total debanding in 17 and palliative treatment by stepwise dilatation of the PAB in 16 patients. Median follow up time was 59 months. The mean reduction of the gradient was more pronounced in the first group (37.0 ± 19.0 vs. 14.5 ± 10.3 mmHg, P < 0.001). The average mean oxygen saturation improved, however, significantly within the palliated group. The median time for reintervention after stepwise dilatation was 9 months. Serious, procedure-related complications occurred in 2 of 42 catheterizations (4.8%). Debanding by catheter replaced surgery in 8 of the 17 patients (47%). CONCLUSION We consider catheter debanding a valuable alternative in selected cases. Combination with additional interventional techniques may extend the future indications.

A novel method of hybrid intraoperative catheter-based closure of ventricular septal defects using the Amplatzer® PDA occluder†

Background: In five patients, an apical muscular septal defect was closed in a hybrid approach using the Amplatzer® duct occluder during open heart surgery, whereas concomitant defects were treated surgically. In addition to their different heart defects that needed surgery, all had a muscular ventricular septal defect in the apex of the heart, poorly accessible for traditional, surgical approach. We describe the method and outcome in these patients. Methods: The tip of a forceps was advanced from the left into the right ventricle through the ventricular septal defect. The delivery sheath was caught under visual control in the right ventricle and pulled back into the left ventricle. The disc was developed and pulled back until it was felt tugging at the septum. Then the core was developed. The end of the device was visible in the right ventricle and was secured with a Prolene® suture. Results: The procedures were event‐free. During early follow‐up there were either no or only insignificant shunts in the region of the prior trabecular defects in four patients. The unsatisfactory result in the last patient was caused by inaccurate preoperative assessment. Conclusion: The method seems valuable in patients in need of other intracardiac surgery.

Does the Administration of Systemic Radiographic Contrast Media Influence the Acute Changes in Renal Physiology Following Exposure to Extracorporeal Shock Waves in Dogs

Five anesthetized dogs were studied for 4 to 5 hours after administration of extracorporeal shock waves to one kidney, the contralateral organ serving as control. Repetitive major doses of the nonionic monomeric radiographic contrast medium (CM) iohexol were injected intravascularly before and after application of the extracorporeal shock waves for further provocation of kidney function. Urinary excretion of electrolytes, N-acetyl-beta-glucosaminidase (NAG) and kallikrein, clearances of creatinine, inulin and para-amino-hippuric acid (PAH), serum aldosterone level and plasma renin activity (PRA) were determined. On the exposed side there was a significant fall in urinary osmolality. Effective renal plasma flow (ERPF) was reduced and glomerular filtration rate (GFR) was unchanged; thus filtration fraction (FF) was increased. Extraction of PAH was reduced, and true renal plasma flow was unchanged. Urinary osmolality on the control side was unchanged. There was a fall in ERPF and increased GFR; therefore, FF increased. The mean rise of PRA in the exposed kidney was significant after shock waves. Urine volume and urinary excretion of electrolytes and kallikrein were stable bilaterally. Relating the results to those obtained in identical canine experiments without CM, simultaneous administration of CM does not seem to significantly influence the changes in kidney function parameters caused by extracorporeal shock waves in the dog.

Catheter based closure of ventricular septal defects.

Abstract Background. Catheter based treatment for heart diseases is increasing. Rikshospitalet has been the leading force in Norway to introduce such methods. We present the results of such treatment for different defects in the ventricular septum (VSD). Material and methods. Thirty seven patients catheterised with the purpose of closing a VSD with catheter-based techniques were reviewed. Two patients had VSD after myocardial infarction, ten had muscular and 25 had perimembranous VSD. Results. In two patients with perimembranous VSD the attempts were unsuccessful. One patient with muscular and one with post-infarction-VSD had to be catheterised twice. All perimembranous VSD, except one, were completely closed (96%). Complications included one patient who developed a complete heart block requiring a pacemaker, and another who got an intermittent left bundle branch block. Of the muscular VSD four (40%) closed completely, but the residual defects were small and clinically insignificant. None of them developed haemolysis. Both patients with post-infarction-VSD had small leaks, but improved clinically. Conclusion. Catheter-based closure of VSD is a good alternative to open heart surgery. At present our own and the reported incidence of complete AV blocks lead us to be cautious when recommending closure of perimembranous VSD.

Technical note: in vitro balloon dilatation of the banded pulmonary artery

The pulmonary artery of unfixated human heart-lung specimens was banded by placing a Dacron tape around the artery and securing the tape with a 5.0 Prolene suture at selected circumferences. The banding was successfully dilated with a balloon catheter in 24 instances. The mean pressure necessary to burst the suture securing the tape was 2.4 atmospheres.

Catheter-Based Closure of an Atrial Septal Defect in Scimitar Syndrome

We report a patient with abnormal systemic blood supply to the right lung and right-sided anomalous pulmonary venous drainage to the inferior vena cava (scimitar syndrome or pulmonary venolobar syndrome). In addition, she had an atrial septal defect, underdeveloped right pulmonary artery, an aberrant right bronchus, and tracheobronchomalacia. She improved markedly after palliative interventional closure of her atrial septal defect.