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H Sievert

Publications and source records attributed to H Sievert.

At least 37 records · Page 2Linked to original sources
PubMed1999

Laser angioplasty of restenosed coronary stents: results of a multicenter surveillance trial. The Laser Angioplasty of Restenosed Stents (LARS) Investigators.

OBJECTIVES: This study evaluated safety and efficacy of excimer laser angioplasty for treatment of restenosed or occluded coronary stents. BACKGROUND: Balloon angioplasty of in-stent restenosis is limited by a high recurrence rate. Debulking by laser angioplasty is a novel concept to treat in-stent restenosis. METHODS: A total of 440 patients with restenoses or occlusions in 527 stents were enrolled for treatment with concentric or eccentric laser catheters and adjunctive balloon angioplasty. RESULTS: Laser angioplasty success (< or =50% diameter stenosis after laser treatment or successful passage with a 2.0-mm or 1.7-mm eccentric laser catheter) was achieved in 92% of patients. Adjunctive balloon angioplasty was performed in 99%. Procedural success (laser angioplasty success followed by < or =30% stenosis with or without balloon angioplasty) was 91%. There was neither a significant difference in success with respect to lesion length, nor were there differences between small and large vessels or native vessels and vein grafts. Success was higher and residual stenosis lower using large or eccentric catheters. Serious adverse events included death (1.6%, not directly laser catheter related), Q-wave myocardial infarction (0.5%), non-Q-wave infarction (2.7%), cardiac tamponade (0.5%) and stent damage (0.5%). Perforations after laser treatment occurred in 0.9% of patients and after balloon angioplasty in 0.2%. Dissections were visible in 4.8% of patients after laser treatment and in 9.3% after balloon angioplasty. Reinterventions during hospitalization were necessary in 0.9% of patients; bypass surgery was performed in 0.2%. CONCLUSIONS: Excimer laser angioplasty with adjunctive balloon angioplasty is a safe and efficient technology to treat in-stent restenoses. These data justify a randomized comparison with balloon angioplasty.

Adult↗
PubMed1999

Transvenous closure of patent ductus arteriosus with Ivalon plugs. Multicenter experience with a new technique.

RATIONALE AND OBJECTIVE: The authors assess the clinical efficacy of transvenous closure of patent ductus arteriosus (PDA) with a new plug consisting of Ivalon foam and a platinum/iridium frame with four aortic and two pulmonary nitinol struts. The most widely used devices for transcatheter treatment of PDA (Porstmann plug, Rashkind umbrella, Botallo occluder, coils) have specific limitations inherent to their design (e.g., transarterial approach, residual shunts, limited retrieval). METHODS: Between 1994 and 1997, PDA closure was attempted in 33 children and 67 adolescents and adults in 7 clinical centers; PDA diameter was 2 to 11 mm. Plug diameter was 6 to 20 mm, and 8 to 16 F venous sheaths were used for insertion. RESULTS: Placement was successful in 98% (with a single plug in 88%, and a second or third plug in 10%) and unsuccessful in 2%. Plugs were retrieved after malpositioning in 12 of 12 patients and after pulmonary embolization in 2 of 3 patients. One patient underwent surgery for removal of an embolized plug. Complete PDA closure was proved by aortography and color Doppler echocardiography in 85% (40 of 43 patients with a PDA 2-3.9 mm, 30 of 36 patients with a PDA 4-5.9 mm, and 15 of 21 patients with a PDA 6-11 mm). During a median follow-up interval of 16 months, there were no complications (infection, hemolysis, fracture, embolization). CONCLUSION: The new plug device can be used successfully in patients with a PDA diameter up to 11 mm. Further investigations are underway to determine the definite clinical value of this technique.

Adolescent↗
PubMed1998

Transcatheter closure of atrial septal defect and patent foramen ovale with ASDOS device (a multi-institutional European trial).

A clinical trial was conducted to assess the feasibility, safety, and efficacy of the atrial septal defect (ASD) occlusion system for transcatheter closure of secundum ASD and patent foramen ovale (PFO) after episodes of cerebral embolism. Occlusion was attempted in 200 patients aged 1 to 74 years (mean 32). The procedure failed in 26 patients (13%); the device was retrieved through a catheter in 20 and through surgery in 6 patients. Procedure-related complications necessitating surgical removal of the device included device embolization in 2, device entrapment within the Chiari network in 1, frame fracture in 1, and perforation of atrial wall in 2. All 6 patients experienced an uneventful postoperative course. An additional 11 patients (6%) underwent surgical removal of the device during follow-up. There were 163 patients (81%) with an implanted ASD occlusion system at follow-up of from 6 to 36 months (mean 17). Thrombus formation around the device was detected by transesophageal echocardiography in 9 patients 1 to 4 weeks after implantation. One of these patients (who had a coagulation factor XII deficiency) suffered a cerebral thromboembolism. Late atrial wall perforation (5, 6, and 8 months after implantation) occurred in 3 adult patients. Infectious endocarditis developed in 2 adult patients (1%). No late device embolization and no atrioventricular valve injury occurred. An asymptomatic device frame fracture was found in 14% and frame deformity in 4% of all patients during the follow-up period of >230 patient-years. Immediately after closure, a moderate/large residual shunt remained in 8% and a small shunt in 29% of patients. After 1 year, a moderate/large shunt was present in 2% and a small one in 26% of patients. During a total follow-up of 49 patient-years, only 1 of 46 patients with PFO had a transient neurologic event after the closure. The study indicates that patients with centrally situated secundum ASD and those with PFO after cerebral embolism can be treated with this system with a high success rate and an acceptable morbidity.

Adolescent↗
PubMed1998

Improved systolic function after PTCA can be estimated by femoral arterial Doppler.

The effect of coronary angioplasty to the post exertional femoral arterial pulse was analyzed in a prospective trial. In 26 patients 30 coronary stenoses could be treated. Narrowed lumen diameter dropped from 85.5% +/-8.2 to 34.6% +/-10.7 (P<0.0001). Patients with a residual coronary artery stenosis of <60% (group A, n=15) were compared to those with incomplete revascularisation (stenoses >60%, group B, n=11). Post exertional Doppler criteria differed between both groups: Peak velocity in group A was 86.08 cm/s +/- 17.8, in group B 72.9 cm/s +/-17, mean velocity 32.06 cm/s +/-12.5 versus 23.6 cm/s +/-10.3 acceleration or dV/dt 813.5 cm/s2 versus 722 cm/s2 +/-164. Statistical significant pre to post postexertional findings improved only in group A (P<0.01, peak velocity, P<0.05 mean velocity and dV/dt). It is concluded that patients with still-existing exertional myocardial ischemia can be distinguished from those without hemodynamic relevant stenoses by means of a simple noninvasive Doppler analysis of femoral arterial pulse.

Angioplasty, Balloon, Coronary↗
PubMed1998

Initial clinical experience with the new EBI (BARD-XT) flexible coronary stent: acute results and follow-up.

The EBI (BARD-XT, C.R. Bard, Murray Hill, NJ) stent is a new radiopaque balloon expandable coronary stent with high resistance to external radial forces. It does not shorten significantly with expansion and allows stent implantation in bifurcation lesions. A total of 28 EBI stents were implanted in 23 lesions in 21 patients. Indications for stent implantation were acute closure in 1, threatened closure in 15, and electively in 7 lesions. In 2 cases, the lesion involved a bifurcation where a stent was implanted in both vessels. All patients received aspirin and ticlopidine. No anticoagulant therapy was given. The stenting procedure was successful in 22 of 23 lesions. No complications occurred with the exception of 1 patient with a thrombotic reocclusion within 1 hr after stent implantation and 1 patient with a temporary occlusion of a side branch. The mean minimal luminal diameter (MLD) increased from 0.74+/-0.46 mm before balloon dilatation to 1.27+/-0.62 mm before stent implantation and 2.32+/-0.57 mm after stent implantation. Percent stenosis decreased from 71+/-19% before angioplasty to 46+/-25% after angioplasty to 5+/-8% after stent implantation. MLD at the time of follow-up angiography after 4 months was 1.98+/-0.77 mm and percent stenosis was 26+/-21%. Restenosis of more than 50% occurred in 2 lesions. In these lesions, a second percutaneous transluminal coronary angioplasty was performed. Advantages of this stent are its flexibility together with an acceptable radial strength as well as enabling radiopacity without obscuring the arterial lumen. Stenting of bifurcation lesions is possible.

Angioplasty, Balloon, Coronary↗
PubMed1998

Percutaneous closure of secundum atrial septal defect with a new self centering device ("angel wings").

OBJECTIVE: To investigate the safety, efficacy, and clinical application of a new self centering device ("angel wings") for closure of secundum atrial septal defects (ASD II) and persistent foramen ovale in all age groups. DESIGN: Multicentre, prospective, nonrandomised study. PATIENTS INCLUSION CRITERIA: defects with an occlusive diameter of < or = 20 mm and a surrounding rim of > 4 mm; body weight > 10 kg; and an indication for surgical closure of secundum atrial septal defect. Additionally, there were compassionate indications for closure in patients with persistent foramen ovale. INTERVENTIONS: Defects were closed by a transcatheter device consisting of two square frames made of superelastic nitinol wire. The frames are covered by elastic polyester fabric, which is sewn together at a central circle. All procedures, except for three interventions that were carried out under sedation, were performed under general anaesthesia using transoesophageal echocardiography and fluoroscopy to monitor intervention. RESULTS: Closure was attempted in 75 (71%) of 105 patients. An ASD II was present in 35 children and 15 adults. A persistent foramen ovale was present in 25 adults with suspected paradoxical embolism. Transcatheter closure was unsuccessful in three children and crossover to surgery was required. Residual shunts were found in 20 patients (27%) immediately after the procedure. A transient atrioventricular third degree block occurred in three patients (4%) and the right atrial disk was not fully deployed in three. A minor shunt (< 3 mm) was present in only three (4%) of 72 patients during follow up of 1-17 months. Blood clots on the right atrial disks in two patients (one required lysis) were seen during follow up transoesophageal echocardiography. Serious complications demanding surgical removal of the device occurred in three patients. One patient had haemopericardial tamponade because of an aortic lesion. Left atrial thrombus formation due to an unfolded right atrial disk was found in a second patient and dislodgement of the left atrial disk resulted in a large residual shunt in a third. CONCLUSIONS: Percutaneous closure of a central ASD with a diameter < or = 20 mm in paediatric and adult patients is feasible and effective with this new device. It is a promising alternative to surgical closure. Modifications of the design, however, seem to be mandatory as 4% of patients developed serious complications.

Adolescent↗
PubMed1997

Recanalization of total coronary occlusions using a laser guidewire (the European TOTAL Surveillance Study).

The success rates of coronary angioplasty for the treatment of chronic total occlusions are less favorable than for coronary stenosis. Therefore, a new laser guidewire (LW) was designed to facilitate the crossing of chronic total occlusions. We report on the results of a European multicenter surveillance study, evaluating the laser guidewire performance. Between May 1994 and July 1996, 345 patients (age 59 +/- 10 years, 291 men) with chronic total occlusions were enrolled in 28 European centers. The median age of occlusion was 29 weeks (range 2 to 884), the occlusion length 19 +/- 10 mm. LW recanalization was successful in 205 patients (59%/). LW perforation occurred in 73 patients (21%), with hemodynamic consequences in 4 (1%). There were no deaths, emergency coronary artery bypass graft surgery, or Q-wave myocardial infarctions. In a multivariate regression analysis an occlusion age of <40 weeks (p = 0.001, RR = 1.34) and an occlusion length <30 mm (p = 0.01, RR = 1.59) were independent predictors of success. Results indicate that the LW is an effective and safe tool in the treatment of chronic total occlusion refractory to conventional guidewires.

Chronic Disease↗
PubMed1997

Myocardial sarcoidosis as a rare cause of sudden cardiac death.

Two relatively young women died suddenly due to myocardial sarcoidosis. Necropsy in both cases revealed compact infiltration of the ventricular septum by fibrous tissue. Histologic sections elucidated extensive granulomatous degeneration and giant cells of the Langhans' and foreign body type without central necrosis of the granulomas. Both women had been entirely free of symptoms, but in the second case of a 35-year-old, who had been 6 months pregnant, an ultrasound sonography of the heart had documented a suspicious area in the ventricular septum interpreted as a scar. Further investigations had been postponed until delivery. Isolated myocardial sarcoidosis should be taken into account as one possible cause of sudden death, especially in young people.

Adult↗
PubMed1997

[A new system for transvenous occlusion of persistent ductus arteriosus].

An Ivalon-plug (PDA-plug) has been developed for transvenous closure of patent ductus arteriosus. It can be introduced into the ductus through standard venous sheaths with a diameter of 8-16 French. The plug is fixed in its target position by means of four distal (aortal) and two proximal (pulmonary) nitinol struts. In case of malpositioning the system can be pulled back into and retrieved through the sheath. In animal experiments endothelialization of the implanted material was demonstrated. PDA-closure was attempted in 58 patient; the procedure was successful in 57 cases; a residual ductal flow was present in eight patients. During a follow-up of up to 24 months there were no complications.

Adolescent↗
PubMed1997

Transcatheter closure of patent ductus arteriosus with the Rashkind occluder. Acute results and angiographic follow-up in adults.

We performed catheter closure of a patent ductus arteriosus with a Rashkind occluder in 51 adult patients (aged 14 to 76 years). The diameter of the ductus ranged from 2 to 13 mm (mean 4.5 +/- 2.0 mm), QP:QS from 1.0 to 2.6 (mean 1.6 +/- 0.3). The procedure was successful in 50/51 patients, in one of them at a second attempt. In one patient, the ductus could not be closed even with additional occluders. This patient was sent for surgery. In two patients with a large ductus, two Rashkind umbrellas were implanted simultaneously. Immediately after ductus closure, there was a residual shunt in 40/50 patients decreasing to 26/50 after 20 min. Two of the patients with a residual shunt suffered from haemolysis. In 16 patients, the residual shunt disappeared spontaneously within some months. In 15 patients, additional occluders (a second occluder in 12, a third occluder in one, and a fourth and fifth occluder in another) were implanted during the initial procedure or during follow-up. All patients were followed until angiography proved complete closure of the ductus. At the time of the last follow-up angiogram, the ductus was occluded in 49/50 patients; one patient refused a follow-up angiogram. Ductus occlusion with the Rashkind umbrella can be considered a technique with a high success rate and low rate of complications in adults. However, a residual shunt is not uncommon. Additional occluders have to be implanted in many patients.

Adolescent↗
PubMed1996

Recanalization of chronic coronary occlusions using a laser wire.

Between August, 1993-December, 1994, recanalization of a chronically occluded coronary artery was attempted in 412 patients, with an overall success rate of 77%. The main reason for failure was subintimal tracking of the guide wire. However, in 13 patients, advancing the guide wire was not possible either subintimally or in the former true lumen. In 8 of these 13 patients with failed conventional recanalization, a second attempt was made using a 0.018" laser wire. The suspected occlusion duration was 6 wk-6 yr, and the occlusion length 6-21 mm. Successful crossing of the occlusion was achieved in 7 of 8 patients. One patient experienced pericardial hematoma without severe clinical consequences. Adjunctive conventional laser angioplasty and/or balloon dilatation led to a residual stenosis of < 50% in 7 patients. The laser wire technique may become an important new method for recanalizing chronic total coronary occlusions in selected patients.

Angioplasty, Balloon, Coronary↗
PubMed1996

Brachial artery approach for transluminal angioplasty of the internal carotid artery.

One possible problem in internal carotid angioplasty is inaccessibility of the lesion due to elongation of the aortic arch, the brachiocephalic trunk, or the carotid artery itself. A new approach to performing angioplasty of the right or left internal carotid artery utilizing the brachial artery was used after failure of the transfemoral approach in 5 lesions (4 patients). The common carotid artery was cannulated with performed 5F catheters. Angioplasty was performed with a conventional balloon dilatation catheter. If required, a Wall stent was implanted to optimize the angiographic result. After failure of the conventional transfemoral technique, the brachial technique permitted successful angioplasty of the ipsilateral internal carotid artery in 4 lesions and the contralateral internal carotid artery in 1 lesion. In 1 patient, a stent was implanted. No complications occurred. The mean stenosis diameter decreased from 77.8 +/- 6.3% to 17.8 +/- 9.1%. Doppler sonography performed 4-6 months later showed no restenosis. The brachial artery approach seems to be a suitable alternative to the femoral technique.

Aged↗
PubMed1996

-Occlusion of atrial septal defect with a new occlusive device-.

An atrial septum defect was closed with an ASDOS (Babic) occluder in 13 patients aged from 22 to 67 years. The diameters of the ASD ranged from 12 to 36 mm, the left to right shunt from 35% to 70%. With one exception, the occluder could be implanted in all patients. Two patients with an oversized ASD (diameter 31 and 36 mm respectively) had to be operated after 8 h and 2 weeks, respectively. In one patient, a small asymptomatic hemopericardium was detected after 24 h by routine echocardiogram and in another patient a single umbrella arm fracture was noticed by routine x-ray 4 months after the implantation. No further complications occurred. Follow-up is now 3 months to 1 year. With one exception, there was no residual shunt as measured by oximetry.

Adult↗
PubMed1995

Transcatheter closure of large atrial septal defects with the Babic system.

An improved 10 Fr version of the atrial septal defect (ASD) occlusion system consisting of two umbrellas for transvenous introduction over the long veno-arterial guide-wire was used to attempt closure in five adult patients with large defects (26-35 mm). The umbrellas are made of nitinol wire frame and a thin membrane of microporous polyurethane. Supported by the metal cannula and guided by selective left atriography, the umbrellas of 45-60 mm were placed individually into the atria and screwed together at the septum level by means of a torquer catheter. Positioning and screwing on, unscrewing, separating, and repositioning the umbrellas up to 17 times were needed to anchor the prosthesis correctly in a patient. The prosthesis could be implanted primarily in all patients (in one at second session). Dislodgement of a 60 mm prosthesis and left atrial perforation with a 55 mm prosthesis required surgery in two patients 8 hours and 2 weeks post procedure, respectively. A single umbrella-arm fracture was noticed in one patient 4 months after the implantation. All five patients were free of symptoms at follow-up after 7-10 months. Transcatheter closure of large ASDs is technically feasible with this system. The morbidity is mainly associated with the implantation of very large umbrellas.

Adult↗
PubMed1995

Transcatheter closure of oversized persistent ductus arteriosus by simultaneous delivery of two Rashkind umbrella devices.

Transcatheter closure of persistent ductus arteriosus (PDA) with a diameter of > 9 mm is considered to be impossible or at least difficult with the occlusion systems that are currently available. We report a simple technique for occluding oversized PDAs with two diameter of 13 mm was successfully occluded in a 40-year-old man. Complete closure without residual shunt was documented by echocardiogram and angiogram.

Adult↗
PubMed1995

Multicenter evaluation of the Strecker tantalum stent for acute coronary occlusion after angioplasty.

The Strecker stent is a balloon-expandable, flexible endoprosthesis constructed of knitted tantalum wire and has been implanted successfully in peripheral arteries. This study presents the first multicenter experience with implantation of this radiopaque device in the coronary arteries in 64 patients of 6591 consecutive percutaneous transluminal coronary balloon angioplasty (PTCA) procedures complicated by abrupt closure. In all except 1 patient the stents (n = 72) were correctly placed, and flow could be reestablished immediately. During hospitalization 12 (19%) patients had stent closures; 5 (8%) patients had Q-wave myocardial infarctions; and 13 (20%) patients underwent bypass surgery (4 on an emergency basis). The in-hospital mortality was 9%: 2 patients died after thrombotic stent occlusions; 2 patients had fatal bleeding complications; and 2 patients died after bypass surgery. Major bleeding complications at the puncture site were observed in 8 (12.5%) patients. Angiograms (n = 45) after 17 +/- 5 weeks revealed a stent patency rate of 89%. Thus the Strecker coronary stent proved to be helpful in the management of acute vessel closure during PTCA. However, in this first series a high incidence of early thrombotic occlusions and bleeding complications warrants close anticoagulation monitoring and limits broader indications.

Angioplasty, Balloon, Coronary↗
PubMed1995

[Crossing chronic coronary artery occlusions with a "laser wire" after failed attempted recanalization with other techniques].

The success rate of catheter recanalization of occluded coronary arteries is 50% to 80%. The reason for failure is frequently an occlusion which is to hard. As examples, two patients are reported with very hard coronary artery occlusions which were 5 months and 2 years old, respectively. There had been prior unsuccessful attempted treatment with other techniques. These occlusions could be recanalized with an 0.018 inch laser wire. Afterwards, a balloon dilatation could be carried out via the laser wire. The procedure was successful in both cases.

Adult↗