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Biomedical subjects

H Sievert

Publications and source records attributed to H Sievert.

At least 55 records · Page 3Linked to original sources
PubMed1995

[A simplified catheter technique for the occlusion of a large persistent ductus arteriosus].

Transcatheter occlusion of a persistent ductus arteriosus with a diameter of more than 9 mm is considered difficult or impossible with the currently available techniques. Usually, these patients have to be operated. We used a simple technique to occlude a 13-mm ductus using two Rashkind umbrellas introduced simultaneously through the left and right femoral veins. Complete closure was demonstrated by echo- and angiography.

Adult↗
PubMed1994

[Long term dilatation after unsuccessful percutaneous transluminal coronary angioplasty].

Between August 1991 and December 1993, a total of 7011 percutaneous transluminal coronary angioplasties (PTCA) were performed. In 24 of them, the acute results were unsatisfactory, an autoperfusion balloon catheter was tolerated without complications and prolonged inflation (30 min to one hour) brought no improvement. In these 24 patients (22 men, two women; mean age 60 [33-81] years) the duration of inflation was, if possible, increased to at least 6 hours. In three patients the inflation had to be terminated after 2 or 4 hours, respectively, because of angina or for technical reasons. In 18 of the 24 patients subsequent angiography demonstrated residual restenosis of less than 50%, with a mean degree of stenosis of 18 +/- 14%. But lasting dilatation was not achieved in 6 patients: occlusion persisted in one and marked residual stenosis in two patients, while stent implantation was required in three. These results indicate that, in case of dissection or acute occlusion with failure after prolonged balloon inflation of 30 to 60 min, extending the duration of inflation to many hours can often produce good results so that stent implantation can be avoided.

Adult↗
PubMed1994

[Non-surgical closure of atrial septal defect in adults. Experiences with the Rashkind and the Sideris occluder].

The possibility of closing an atrial septal defect in adults by means of a percutaneously introduced catheter with an umbrella-type occluder was tested in seven consecutive patients with this defect (two men and five women, aged 35 to 69 years). The diameter of the defect (echocardiographic measurement) ranged from 7 to 25 mm, the left to right shunt from 11% to 54% of pulmonary flow and the pulmonary artery pressure from 24/8 to 110/25 mmHg. In one patient no attempt was made to close the defect because of its size (invasively measured: 40 mm). In another patient the method failed. Closure was successful in four of the patients (left to right shunt < 5%), while in a fifth patient a haemodynamically significant residual shunt (38%) remained, but was closed 2 months later with a second occluder. In one of the patients a portion of the device embolized to the pulmonary artery from which it was removed by catheter.--Thus the intervention was successful in five of six patients. This experience suggests that this type of occluder can also be used successfully in adults.

Adult↗
PubMed1994

[Retrograde catheter recanalization of long-range occlusion of the superficial femoral artery].

In a prospective study between March 1992 and October 1993, 50 consecutive patients (47 men, three women; mean age 59.7 [42-73] years) with a total of 52 occlusions of the superficial femoral artery underwent retrograde recanalization via the popliteal artery. The patients were in clinical stage IIa (n = 7), IIb (n = 38) or III (n = 5). The mean Doppler ratio (ankle/arm) was 0.51 +/- 0.14, mean length of occlusion 19 +/- 9 [4-40] cm. Popliteal puncture was successful in all patients but one. The occlusion was passed by guide-wire in 38, subsequently by balloon catheter in 37. Additional laser angioplasty had to be performed in five patients, while stent implantation was necessary in another five. 35 of 52 vessels (in 33 patients) remained open and free of significant stenosis after the procedure. The mean ankle/arm Doppler ratio was 0.5 +/- 0.13 immediately before the angioplasty, 0.72 +/- 0.17 (P < 0.05) immediately afterwards. There were no complications ascribable to the technique except in two cases in which an asymptomatic arteriovenous fistula developed. These results indicate that retrograde recanalization of the superficial femoral artery is a relatively reliable and successful catheter technique in patients who would otherwise have to be treated by surgery.

Adult↗
PubMed1994

[Angiography follow-up after transluminal angioplasty of coronary bypass grafts].

Between January 1979 and October 1991, percutaneous transluminal angioplasty of stenosed or occluded coronary bypass grafts was attempted 180 times in 146 patients (180 lesions in 157 bypass grafts); 6/157 grafts were internal mammary grafts. The procedure was successful in 129/157 grafts (82%) and in 151/180 lesions (84%). Failures occurred almost exclusively in recanalization attempts. Cardiac complications occurred in 4/146 patients (2.7%). Three patients developed an acute myocardial infarction, another patient died after acute occlusion of a native vessel dilated during the same procedure. In successful attempts the severity of stenosis was reduced from 87 +/- 10% to 33 +/- 15%. 113/129 successfully dilated grafts had at least one (mean 2.7) control angiogram. 54/113 (48%) showed recurrence after a mean follow up of 6 months. An additional 15 grafts showed late restenosis in a second control angiogram (mean follow-up 23 months). The total restenosis rate was 61%. Restenoses were dilated again one to six times (mean 1.9) with comparable success and recurrence rate. Two patients died during the sixth angioplasty. Finally, 32/129 (25%) grafts were occluded or presumably occluded, and 97/129 (75%) were angiographically confirmed open without restenosis. Thus, angioplasty of bypass grafts is an alternative to a repeat revascularization surgery. The acute results are comparable to the results of angioplasty in native coronary arteries. The restenosis rate is high. One has to be aware of late restenosis. Restenosis can be dilated repeatedly with a comparable success rate and with no significant increase in restenosis rate.

Adult↗
PubMed1994

[A new radiation protection device for cardiologists active in interventional radiology].

The radiation protection system up to now has been in the form of a lead glass pane and a lead curtain on the examination table. As new equipment we used a leaded rubber cover (Pb 0.75 mm) extending from the foot to the rib cage of the patient and a 60-cm high and 70-cm wide stand, reinforced with leaded rubber (Pb 1.0 mm) fixed onto the foot switch. During the period of 2 months the total radiation dose in 156 coronary angioplasties and 71 diagnostic heart catheterizations was measured on the hand, thorax, lower leg and foot of the examiner using ring and placet dosimeters. The dose was measured for a further 2 months, during 152 coronary angioplasty and 66 diagnostic heart catheterizations without the new extra radiation protection equipment. The catheterization procedure was not basically impeded through the lead cover and the lead stand. The radiation dose experienced by the examiner was reduced by 96.8% on the hand, 98.6% on the thorax, 98.8% on the lower leg, and by 99.5% on the foot.

Angioplasty, Balloon, Coronary↗
PubMed1994

[Severe mechanical hemolysis after incomplete ductus arteriosus closure: implantation of a second Rashkind occluder].

A 72 year-old female patient with a persistent ductus arteriosus suffered from a severe mechanical hemolysis after incomplete PDA closure with a Rashkind occluder. The residual shunt was closed with a second occluder 2 days later. Hemolysis was stopped immediately; complete closure of the duct was confirmed by color Doppler 6 weeks and 6 months later.

Acute Kidney Injury↗
PubMed1993

SIN-1 has no direct myocardial anti-ischemic action.

Anti-ischemic drugs may develop their cardiac activity via peripheral (reduction in preload and/or afterload) or cardiac (coronary vasculature, myocardial cell metabolism) effects. The aim of the study was to investigate whether SIN-1, the active metabolite of molsidomine, develops a direct myocardial anti-ischemic property. Three groups of seven patients each were treated with 0.4 mg SIN-1 administered via either the intracoronary (IC) or intravenous (IV) route, or with placebo in a double-blind randomized investigation. SIN-1 had no influence on either the ischemic parameters in the surface electrocardiogram (ECG) or the intracoronary ECG. There was also no change in peripheral or central hemodynamics or in the severity of angina following this low IC or IV dosage. There is no evidence of a direct myocardial anti-ischemic response of SIN-1. The well known anti-ischemic activity of SIN-1 or molsidomine has to be attributed to the proven peripheral and cardiac vascular responses.

Angioplasty, Balloon, Coronary↗
PubMed1993

Myocardial cytoprotection during percutaneous transluminal coronary angioplasty.

Transluminal coronary angioplasty (PTCA) is a well defined controlled model inducing regional myocardial ischaemia in man. Direct cardiac anti-ischaemic effects of anti-anginal drugs can be assessed by intracoronary injection of small doses which do not affect systemic parameters. Trimetazidine (TMZ) has recently been shown to improve anginal symptoms without modifying haemodynamic variables. A randomized, double-blind, placebo-controlled trial was conducted in 20 patients to study the effects of TMZ on the severity of myocardial ischaemia during PTCA of the left anterior descending coronary artery. Five minutes after a first successful dilation (D0), a control balloon inflation (D1) was performed until onset of ischaemic signs on both the intracoronary (i.c.) and precordial ECG. Two minutes later, patients received either trimetazidine 6 mg or placebo i.c. Another inflation (D2) was performed 5 min after D1. No differences were found between the two groups regarding responses in heart rate, systemic and i.c. pressures during the study. TMZ decreased maximum ST segment shift at D2 as compared to D1 (0.8 +/- 0.1 vs 1.4 +/- 0.3 mV, P = 0.023) and delayed its onset (46 +/- 4 vs 36 +/- 5 s, P = 0.024). TMZ also decreased maximum T wave changes (1.06 +/- 0.24 vs 2.19 +/- 0.3 mV, P = 0.001), and significantly reduced the area under the curve (AUC:mV.s-1) of the i.c. ST segment and T wave changes during balloon inflation (P = 0.002 and P < 0.001 respectively). Placebo had no effect on any of these parameters.(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Balloon, Coronary↗
PubMed1993

Left main coronary artery stenosis after aortic valve replacement: genetic disposition for accelerated arteriosclerosis after injury of the intact human coronary artery?

BACKGROUND: Left main coronary artery stenosis is a rare but life-threatening complication after aortic valve replacement because of coronary perfusion-related trauma to the vessel wall with cannulation of the coronary ostia. We investigated whether this complication still occurs in the 1990s despite the use of more advanced catheter materials and modern surgical preservation techniques. METHODS: Four years after identification of the first two cases in 1987, five further patients had developed left main coronary artery stenosis after aortic valve replacement (incidence, 0.9%) at the cardiothoracic clinic of the J.W. Goethe University and were studied for contributing factors. RESULTS: Severe coronary ostial stenosis developed within 1 to 6 months after aortic valve replacement. In one such case, intimal proliferation was seen in a biopsy specimen that was comparable to the restenosis induced by coronary angioplasty. The clinical characteristics of the patients developing the complication, the surgical technique, and the intraoperative course did not differ from the other patients. However, five of the seven patients (71%) had a common genetic trait concerning their apolipoprotein E genotype (the epsilon 4 allele) that is normally present in only 10% to 15% of patients screened (P < 0.01). CONCLUSIONS: These lesions seem to result from a uniform response of the vessel wall to injury. Their incidence is probably related in part to the degree of injury after trauma to the coronary ostia during cannulation for myocardial protection. Patients with the epsilon 4 allele might be genetically predisposed for a pathologically increased response of proliferative repair mechanisms after arterial injury. The complication can be avoided by not instrumenting the coronary ostia for direct antegrade cardioplegia but using retrograde delivery as an alternative method of myocardial protection.

Adult↗
PubMed1993

[Extraction of a ruptured PTCA balloon catheter].

While attempting angioplasty of a very tight and long circumflex lesion with a metal-shafted monorail catheter, the flexible part of the balloon catheter shaft broke off within the guiding catheter. The lost piece of catheter was then retrieved from the coronary artery by using an on-the-wire balloon catheter that was inflated inside the distal end of the guiding catheter.

Angioplasty, Balloon, Coronary↗
PubMed1993

[High frequency rotational angioplasty (rotablation) after unsuccessful balloon dilatation].

From April 1991 to March 1992, 2442 balloon dilatations were carried out. In 36/2442 patients (1.5%), a high-degree coronary stenosis or a coronary occlusion could be passed with a guide wire, but not with a balloon catheter or a recanalization catheter. In 32 of these 36 cases, the conventional coronary guide wire could be exchanged with the 0.009 inch guide wire required for rotational angioplasty. A sufficient increase in stenosis diameter could be attained by rotablation alone in 15 cases. A balloon dilatation was carried out after the rotablation in 17 cases. In one case, implantation of a stent was necessary in addition. The mean degree of stenosis was reduced from 95 +/- 10 to 33 +/- 6%. Thus, high-grade coronary stenoses and occlusions which cannot be passed with a balloon catheter, can be treated successfully with rotablation in a high percentage of cases.

Adult↗
PubMed1993

[Follow-up angiography after balloon dilatation of aortic isthmus stenoses in adults].

Between May 1985 and April 1991, 30 patients (seven females and 23 males) 14 to 54 years old (median, 25 years) underwent balloon angioplasty for unoperated native (n = 26) or recurrent postoperative (n = 4) coarctation of the aorta. 28/30 patients had systemic hypertension (RR > 140/90 mmHg). Dilatation of the stenotic segment could be achieved in 28/30 patients. The residual pressure gradient was > 30 mmHg in six patients. In 2/4 patients with recurrent coarctation the balloon had ruptured, while dilatation was successful in the other two patients. The mean diameter of the stenotic segment increased from 5.8 +/- 2.7 mm to 11.9 +/- 2.5 mm and the peak pressure gradient decreased from 61 +/- 18 mmHg to 20 +/- 13 mmHg. Complications were a small hemorrhagic pleural effusion in one patient and a groin hematoma in another patient. Clinical follow-up studies with retrograde catheterization of the aorta and angiography were performed in all 28 patients with dilated coarctation, 6 months to 6 years after the procedure, representing a total follow-up time of 72 (average, 2.6) patient-years. Multiple follow-up studies (n = 2-4) were performed in 17/28 patients. In one patient the first angiogram revealed aneurysm formation while a small bulge was seen in two others. Intra-aortic pressure measurements revealed a peak gradient of < 30 mmHg in 24/28 patients with a mean of 14 +/- 10 mmHg. The blood pressure was normal in 23/28 patients. In the other five patients whose pressure gradients were 7, 30, 30, 35, and 60 mmHg moderate hypertension persisted.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Myocardial protection during percutaneous transluminal coronary angioplasty: effects of trimetazidine.

Trimetazidine (TMZ) has recently been shown to improve anginal symptoms without altering haemodynamic variables. A randomized, double-blind, placebo-controlled study was conducted in 20 patients to study the effects of TMZ on the severity of myocardial ischaemia during PTCA of the left anterior descending coronary artery. Five minutes after a first successful dilatation (D0), a control balloon inflation (D1) was performed until onset of ischaemic signs on both the intracoronary (i.c.) and precordial ECG. Two minutes later, patients received either TMZ 6 mg or placebo i.c. Another inflation (D2) was performed 5 min after D1. No differences were found between the two groups regarding responses in heart rate, systemic and i.c. pressures during the study. TMZ decreased the maximum ST-segment shift at D2 compared with D1 (0.8 +/- 0.1 vs 1.4 +/- 0.3 mV, P = 0.023) and delayed its onset (46 +/- 4 vs 36 +/- 5 s, P = 0.024). TMZ also decreased maximum T-wave changes (1.06 +/- 0.24 vs 2.19 +/- 0.3 mV, P = 0.001), and significantly reduced the area under the curve (mv s-1) of the i.c. ST-segment and T-wave changes during balloon inflation (P = 0.042 and P = 0.009 respectively). The placebo had no effect on these parameters. These results support the hypothesis that trimetazidine has a direct anti-ischaemic effect on human myocardial cells.

Angioplasty, Balloon, Coronary↗
PubMed1992

Nonoperative closure of the patent ductus arteriosus: the Frankfurt experience.

Nonoperative closure of patent ductus arteriosus (PDA) by means of Ivalon plugs (according to the technique of Porstmann) was performed in 101 patients. Sixty-five patients were symptomatic, the Q p/Q s ratio exceeded 1.5 in 56 patients, and pulmonary hypertension (mean pulmonary artery pressure greater than 20 mmHg) was present in 50 patients. In 100/101 patients the PDA could be closed successfully. Ninety-nine patients were without any evidence of residual left-to-right shunt. In one patient a hemodynamically insignificant left-to-right shunt was found with color Doppler echocardiography. Complications were pulmonary embolism due to plug dislocation in two patients (12th and 14th patient; 2 and 7 weeks after the procedure, respectively). One of these patients underwent elective surgery with patch closure of the ductus and removal of the embolized plug. In the other patient the ductus was successfully closed with a second larger plug while the first plug was left in a peripheral pulmonary artery. Surgical revision of the femoral artery was required in six and blood transfusion in two patients. Deep venous thrombosis developed in two patients. During follow-up (total follow-up time more than 200 patient years) no late complications were observed. In conclusion, transfemoral catheter closure of PDA by means of Ivalon plugs is an effective method. It is applicable to adolescents and adults with a low complication rate. The ductus can be closed without residual left-to-right shunt. Long-term results are excellent.

Adolescent↗