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Biomedical subjects

P Ewert

Publications and source records attributed to P Ewert.

52 records · Page 3Linked to original sources
PubMed1999

Transcatheter closure as standard treatment for most interatrial defects: experience in 200 patients treated with the Amplatzer Septal Occluder.

To judge whether an Amplatzer Septal Occluder can be used as standard therapy instead of surgery for closure of atrial septal defects we report our experiences in 200 patients. Of these patients, 127 had an atrial septal defect with haemodynamically significant left-to-right shunt, 68 patients a persistent oval foramen after presumed paradoxical embolism, and 5 had a fenestration after Fontan-repair. Mean age was 29.8 years (0.8 to 77.7 years). Body weight ranged from 6.9 to 120.0 kg (mean 51.5 kg). After diagnostic cardiac catheterization, and balloon-sizing of the defect, we implanted Amplatzer Septal Occluders with stents of 4 to 28 mm diameter. Follow-up studies were obtained after 48 hours, and one, six, and twelve months. Transcatheter closure of the atrial septal defect proved successful in all without any relevant residual shunts. In particular, complete closure was achieved in all patients after presumed paradoxical embolism. The mean period of follow-up is 9.5 months, with a range from 0.4 to 23.5 months, giving a total of 1898 patient months. The occlusion rate after three month was 98.1%. A trivial haemodynamically insignificant residual shunt remained in 1.9% of the patients. Fluoroscopy times ranged from 0 to 43.5 minutes, with a median of 8.7 minutes. The excellent results in the short and medium term in children and adults have resulted in using this device routinely at the present time for closure of central atrial septal defects up to a diameter of 28 mm. Final judgement, however, is only possible after long-term follow-up.

Adult↗
PubMed1999

Comparison of acute effects on right ventricular haemodynamics of surgical versus interventional closure of atrial septal defects.

OBJECTIVES: We compared the acute effects on right ventricular haemodynamics of surgical versus transcatheter closure of medium-sized atrial septal defects. METHODS: We studied 47 consecutive patients with a defect in the oval fossa and a ratio of pulmonary to systemic flows between 1.5: 1 and 2: 1. They were divided into two groups according to whether the defects were closed by surgery, performed in 23 patients, or by interventional catheterization, achieved in 24 patients. By means of transthoracic cross-sectional echocardiography, we measured right ventricular end-diastolic and endsystolic volumes and calculated ejection fractions. These calculations were performed before, and between 1 and 7 days after closure of the defect. RESULTS: Before closure of the defect, all patients had an enlarged right ventricle with normal function. After closure by either method, there was no difference in the rate of normalization of end-diastolic volume, but endsystolic volume remained enlarged. Thus, the calculated ejection fraction was lower than before closure. CONCLUSIONS: There was no difference in right ventricular volumes or function early after closure of atrial septal defects, irrespective of whether this was achieved surgically or via transcatheter closure.

Adolescent↗
PubMed1999

Continuous monitoring of cardiac output in neonates using an intra-aortic Doppler probe.

Continuous monitoring of cardiac output in neonates would be of considerable benefit but, as yet, there is no practical method to achieve this aim. We have now evaluated the feasibility of using an intra-aortic Doppler probe. We introduced a pulsed Doppler probe of 0.46 mm diameter via the umbilical artery in two term and four preterm neonates. Indications in all patients for umbilical arterial catheter is always an unstable cardiopulmonary state. Body weights were between 770 and 3340 g. Velocities of blood flow in the thoracic aorta were continuously recorded to estimate cardiac output on-line for 12 h. No complications were encountered. It proved possible to derive high-quality Doppler curves. The received Doppler signal was stable but it proved sensitive to pathophysiologic changes in flow. Mean velocity of flow in the descending aorta was 16.4 cm/s (range 13.3-19.0 cm/s). We quantified flow by multiplying the mean velocity of the flow by the cross-sectional area of the descending aorta. Calculated mean flow was 135 ml/kg/min (range 111-179 ml/kg/min). These values are consistent with those measured by transcutaneous Doppler, and it should not be raised by left-to-right ductal shunts. This pilot study proved the feasibility of continuous monitoring of cardiac output. The technique should prove of great value in those infants with unstable circulatory conditions, and can be used even in infants with extremely low birth weights.

Cardiac Output↗
PubMed1999

Transcatheter closure of atrial septal defects under echocardiographic guidance without X-ray: initial experiences.

BACKGROUND: Transcatheter closure of atrial septal defects is performed under fluoroscopy, but echocardiography has gained an important role in the procedure. With the new Amplatzer Septal Occluder a device has become available which is easy to implant with minimal fluoroscopy time. We developed an interventional procedure with this device under transesophageal echocardiography alone without fluoroscopy. METHODS AND RESULTS: Four patients (3 to 16 years of age, bodyweight 14 to 60 kg) with atrial septal defects centrally located in the oval fossa were elected for transcatheter closure. After sedation with midazolam and propofol a diagnostic and interventional catheterization was performed in all cases without fluoroscopy. Oxymetric shunt was Qp: Qs = 1.7 (1.5 to 2.1). Under transesophageal echocardiography, the defects were sized over the wire with a balloon catheter. Mean balloon stretched diameter was 10 mm (7 to 14 mm). Under transesophageal echocardiography an Amplatzer Septal Occluder was placed into the defect. In two patients this was achieved with a 5 MHz monoplane pediatric transducer, in two patients a 10mm 5 MHz multiplane probe was used. Complete closure was achieved in all patients and no complications were encountered. CONCLUSION: We conclude that in selected cases with an atrial septal defect located in the oval fossa and clear-cut echocardiographic findings, an Amplatzer Septal Occluder can be safely deployed under echocardiographic guidance alone.

Adolescent↗
PubMed1999

Changes in ventricular and muscle volumes of neonates.

BACKGROUND: To examine the changes in cardiac ventricular and muscle volumes in neonates, echocardiography was performed in 25 normal neonates at 3-5 and 30-35 days after birth. METHODS: A standard apical four chamber view and a parasternal short axis view were used for the analysis of the left ventricle. For the analysis of the right ventricle, only an apical four-chamber view was used. A formula based on the area length method was used to calculate the left ventricular and muscle volumes and the single plane Simpson's rule was used for the right ventricular and muscle volumes. RESULTS: The left ventricular and muscle volumes per body surface did not change during the month following birth. The ratio of the muscle to ventricular volume of the left ventricle was also unchanged. However, the ratios of the right muscle volume to body surface and to the ventricular volume decreased after one month. CONCLUSIONS: The authors suggest that the decreases in pulmonary hypertension and right ventricular stroke volume play a role in the changes of right muscle volume.

Age Factors↗
PubMed1998

[Initial clinical results with the Amplatzer septal occluder--a self-centering double disc for occlusion of atrial septal defects].

UNLABELLED: In recent years many different systems for transcatheter closure of an atrial septal defect (ASD) have been developed and tested. However, all systems presently available have some special disadvantages. The recently introduced Amplatzer Septal Occluder (ASO), though, appears promising. It is a self-expanding and self-centering double disc made from a Nitinol mesh, which is tightly woven to give mechanical strength. Both discs are separated by a connecting cylindrical portion. Its diameter may be chosen, so that it corresponds to that of the ASD. Discs of polyester patches are sewn into the retention discs as well as into the cylindrical portion of the device in order to augment thrombogenicity. After measuring the diameter of the ASD with a balloon, an appropriate ASO is selected and advanced into the left atrium through a 7 or 8 French sheath. Then the distal disc and part of the connecting cylindrical portion is developed in the left atrium and pulled against the atrial septum, so that the cylindrical portion is occluding the ASD. Thereafter, proximal disc is deployed and the delivery cable disconnected. As long as the cable is connected to the device repositioning is easily achieved by pulling the device back into the sheath. Within a time period of 4 months in 29 out of 31 patients (median age: 12.1 years, median weight: 45.0 kg) complete closure of the ASD with a mean diameter of 11.0 mm (6-20 mm) was achieved without complications, the average fluoroscopy time being 8.3 min (2.9-21.5 min). Mean Qp:Qs was 1.5 (0.9-2.2). During a mean follow-up period of 2.1 months post implantation fixed seating of the ASO without residual shunt, arrhythmias, thrombembolic events and impairment of A-V valves was observed in all patients. CONCLUSION: The Amplatzer septal occluder allows quick, safe, and complete closure of atrial septal defects without complications if one adheres to strict implantation criteria. For a final judgement, however, long-term follow-up studies are necessary.

Adolescent↗
PubMed1998

A modified repair technique for tricuspid incompetence in Ebstein's anomaly.

OBJECTIVE: A modified technique for tricuspid valve repair in Ebstein's anomaly restructures the valve mechanism at the level of the true tricuspid anulus by using the most mobile leaflet for valve closure without plication of the atrialized chamber. Midterm results of this therapeutic approach for patients with Ebstein's anomaly and tricuspid valve incompetence are reported. METHODS: Between October 1988 and April 1997, the incompetent tricuspid valve was repaired with our technique in 19 patients (12 female, 7 male; 2 to 54 years, mean 21 years). The indication for operation was congestive heart failure of various degrees in all patients. Tricuspid incompetence was grade II in two patients, grade III in 14, and grade IV in three. Associated congenital malformations were simultaneously repaired (interatrial communication in 18, ventricular septal defect in two, pulmonary stenosis in two, mitral valve prolapse in one). Follow-up ranged between 10 and 103 months (median 28 months) and was complete for all patients. RESULTS: There were no operative deaths. One patient with active endocarditis and pulmonary abscess died 2 months after the operation of recurrent sepsis; there were no late deaths. During follow-up, New York Heart Association functional class improved from 2.8 before the operation to 1.9 without recurrent cyanosis, and tricuspid incompetence decreased from a mean grade of 3.1 to one of 0.9, without any echocardiographic deterioration of the tricuspid valve function or right ventricular dilation. CONCLUSIONS: Our technique allows tricuspid valve repair in patients with Ebstein's anomaly, even in cases usually reserved for primary valve replacement, without late functional deterioration.

Adult↗
PubMed1997

Change in cardiac diastolic function in neonates.

In this study we used Doppler echocardiography to examine changes in ventricular diastolic function in neonates. Echocardiograms were performed in 25 healthy neonates at 1-6 days (2.7+/-1.6 days) and at 25-35 days (29.4+/-3.3 days) after birth. Ventricular inflow velocity curves were recorded using the pulsed-Doppler method. Peak velocities (peak E, A). mean velocities (mean E, A), times (time E, A), and diastolic velocity-time integrals (area E, A) were measured during both early ventricular filling and atrial systole. The acceleration time of the wave during early ventricular filling was also measured. Peak E and A and mean E and A in both ventricles increased at 1 month after birth. Acceleration times in both ventricles were shortened. The ratio of area E to A in both ventricles and of peak E to A in the left ventricle did not change at 1 month after birth. Only the ratio of peak E to A in the right ventricle increased. The ratio of peak E to (area E + area A), which is thought to be a load-independent index, increased in both ventricles. The authors concluded that ventricular relaxation appears to increase in both ventricles, 1 month after birth, and that changes in diastolic function occur even in neonates.

Diastole↗
PubMed1992

[Trichobezoar. A rare cause of recurrent upper abdominal pain].

Recurrent abdominal pain in a two years old toddler and a sixteen years old girl were caused by huge trichobezoars, which in one case had a weight of 412 g and provoked a gastric ulcus. Removal was possible only by gastrotomy. Deprivation in infancy and childhood in combination with slight mental retardation had led the teenager to trichtillomania and -phagia for years and finally to a bezoar. A short historic survey of the variety and therapy of bezoars is added.

Abdominal Pain↗
PubMed1990

[Typical CT findings with the intrathecal infusion test in post-traumatic disorders of cerebrospinal fluid dynamics].

Simultaneous computer tomographic and cerebrospinal fluid dynamics examinations in patients with high-pressure hydrocephalus, normal pressure hydrocephalus and cerebral atrophic processes are presented and discussed. Exclusive CT and MR examinations do not allow a differentiation of patients with normal pressure hydrocephalus and patients with cerebral atrophy. In the simultaneous examinations the morphological substrate during the intrathecal infusion test is represented.

Adult↗
PubMed1990

[Axial osteosynthesis of dens axis fracture as a routine procedure in neurotraumatology. Diagnosis--Surgical-technique--Complications--Follow-up].

A survey on 34 cases of odontoid process fractures treated by means of axial osteosynthesis since 1981. In cases of acute fractures rate of bony consolidation was 100%, in cases of pseudoarthrosis 50%. 6 complications until the first 20 weeks were successfully treated. No later complications. Removal of implanted material is usually not necessary. Operative treatment of non union by means of bony grafting, axial osteosynthesis and atlanto-axial arthrodesis seems to be helpful. Investigations for the best implantation model must be continued.

Adolescent↗
PubMed1989

[Fixateur externe as a definitive treatment method of unstable thoracolumbar spinal fractures in emergency conditions--technical modification and clinical experiences].

A survey on 31 injuries of thoracolumbar spine, 27 were accompanied with neurological deficiency. Treatment was exclusively by means of percutan attached f.e. until bony consolidation. An average treatment time of 152 days took place. Mean rate of correction was about 0.24 (Beck's SI-Index). The former applied frame construction was substituted by self developed spindle fixateur system, adapted to the requirements of traumatology of the spine in emergency situations.

Adolescent↗
PubMed1987

[Instrumentation for hollow screw osteosynthesis of basal dens axis fractures].

The trend in the treatment of odontoid bone fractures is characterized by progressive application of operative methods. Special instruments for the fixation of odontoid bone was developed. Due to the ventral extraoral approach odontoid bone is possible to fix temporary with two rigid Kirschner wires by these hollow screws drilled from the ventral lower edge of the second vertebral body through the fracture in the odontoid bone. By using this method the operative procedure is much more safety as well as the x-ray exposure of the patient and of the operating team is reduced.

Axis, Cervical Vertebra↗
PubMedDate not supplied

Comparison of analgesic/sedative effect of racemic ketamine and S(+)-ketamine during cardiac catheterization in newborns and children.

The hypnotic and analgesic effect of ketamine with maintained spontaneous breathing is used for analgesic/sedative anesthesia without the need of intubation. The intention of this study was to compare the efficacy and side effects of racemic ketamine and its enantiomer S(+)-ketamine during cardiac catheterization in newborns and children. One hundred children (ages 0-11 years) were randomly assigned to groups of equal size. The differences between the racemic ketamine/midazolam and the S(+)-ketamine/midazolam groups were investigated regarding the total dosage of sedative drugs, side effects, and the awakening period. The dosage of S(+)-ketamine (2.28 mg/kg/h) was significantly lower than that needed for racemic ketamine (3.12 mg/kg/h) (p = 0.037) with an analgesic/sedative potency ratio of 1.4:1. Balloon dilatation required significantly higher dosages in both groups (p = 0.043). Significantly more patients were excluded because of ineffective analgesia/sedation or severe side effects in the racemic ketamine group. The awakening period did not show significant differences between the two groups. S(+)-ketamine proved to be a more efficient analgesic/sedative drug in newborns and children. It was shown to be useful in diagnostic and interventional procedures and allows spontaneous breathing. Moderate side effects occurred in both groups; severe side effects seemed to occur more often with the racemic solution.

Analgesics↗
PubMedDate not supplied

Challenges encountered during closure of patent ductus arteriosus.

Transcatheter closure of patent ductus arteriosus (PDA) was one of the first interventions established in invasive cardiology and is now more than 30 years old. The challenges for successful closure with the first devices in children consisted of handling the rather large introducer sheaths and stiff application systems. Today, interventional closure can be performed with different types of plugs, occluders, and coils. Thus, beyond infancy, transcatheter closure can be successfully performed in almost all cases. Challenging from the technical standpoint can be the closure of window-type ducts, in which excessive protrusion of the device into the descending aorta should be avoided, as well as the closure of tubular ducts, in which secure anchoring of one or more devices in the vessel can be very difficult. For the combination of a coarctation and an open duct, different strategies can be considered. In selected cases, use of a covered stent can be helpful. From the physiological standpoint, open ducts in patients with pulmonary hypertension with or without concomitant congenital heart diseases can be challenging because testing of vasoreactivity with temporarily blocked duct and the option of subsequent treatment with vasodilators may be necessary prior to making the decision whether the patient may benefit from definitive duct occlusion or not. Large ducts in infants less than 8 kg can be difficult to treat due to a relative mismatch of introducers, plugs, or occluders to the small anatomic dimensions. The implantation of multiple coils can be associated with a higher risk of device embolization. Unfortunately, for the large group of preterm infants with very low body weights and large ducts of tubular shape there is currently no standardized interventional therapy available.

Balloon Occlusion↗