Biomedical subjects

H Sievert

Publications and source records attributed to H Sievert.

At least 73 records · Page 4Linked to original sources

PubMed1992

Acute and mid-term experiences with the Wiktor stent in acute complications and restenosis after coronary angioplasty.

We report about the 6-month follow-up of 28 consecutive patients treated with a new tantalum stent (Wiktor¿ stent, Medtronic, Inc.). Indication for stenting was the prevention of restenosis in eight patients (restenosis group), and threatening or acute closure after PTCA in 20 patients (acute closure group). Twenty-eight of 30 stents were successfully positioned in 27 of 28 patients (96%), whereas implantation failed twice in one patient. Immediate stent occlusion developed in two patients in the acute closure group (7.4%) Subacute stent occlusion was observed in three patients (11%), one in the restenosis group, two in the acute closure group, between 3 and 5 days after implantation. Coronary bypass surgery had to be performed in four patients (15%): one patient after failed stent placement, two after acute, and one after subacute stent thrombosis. Major bleeding complications related to the anticoagulative drug regimen occurred in nine patients (33%). Three patients (11%) died for reasons most probably not related to stent implantation. A 6-month angiographic follow-up revealed restenosis in two of 19 patients (11%), one patient in each group. Sixteen of the 27 stented patients (59%) reached 6-month follow-up without death, acute or subacute stent thrombosis, or restenosis. It is concluded that the Wiktor stent can be placed with a high rate of success. It may also reduce the risk of restenosis. The stent also offers the possibility to circumvent emergency bypass surgery in case of PTCA related vessel occlusion. Acute and subacute stent occlusion still remains an unsolved topic.

Adult↗

PubMed1992

[Chronic coronary artery occlusion--age, morphology and chance of reopening. An attempt to define indications].

In chronic coronary occlusions the rate of successful reopening seems to be improved with the help of new techniques; the chance of success can be judged by the age of occlusion. Frequently this age cannot be fixed exactly. The purpose of the study was therefore to find out, whether the chance of reopening can be judged by morphology. 60 patients in whom the occlusions could not be passed with a conventional wire were treated with the ROTACS system. Cine angios were reviewed carefully, morphological details in at least two projections were evaluated in graphic representations and correlated with the acute success rate and the estimated age of occlusion. Morphological parameters associated with a higher rate of success (type A) were: 1) a clearcut proximal stump with 2) no sidebranches at the site of occlusion, 3) no bridging collaterals and 4) only a slight filling of the distal vessel. Parameters with a low success rate (type B) were: 1) no proximal stump, 2) sidebranches at the site of occlusion, 3) bridging collaterals and 4) a very good distal filling. 48/60 (80%) of occlusions could be classified in type A or type B. The success rate was 17/21 (81%) (type A) versus 5/27 (18.5%) (type B) (p < 0.0002). The estimated age of type B occlusions was significantly higher than in type A: median 8 versus median 4 months (p < 0.002). It is concluded that the rate of success in reopening chronic coronary occlusions can be judged in the majority of patients using morphological parameters.

Atherectomy, Coronary↗

PubMed1992

[Unexpected complication of anticoagulation after implantation of a coronary stent].

After stent implantation there is a high risk of acute stent thrombosis. Therefore, a very aggressive anticoagulation drug regimen is necessary. Two patients developed large hematomas of the upperarm that where presumably caused by automatic blood pressure measuring equipment or by a tourniquet used during blood collection. In one patient a complete paralysis of the ulnar and radial nerves resulted.

Angioplasty, Balloon, Coronary↗

PubMed1991

[Successful directional coronary atherectomy after futile attempts at balloon dilatation].

Coronary arteriography revealed severe stenoses of the proximal part of the anterior interventricular branch with normal ventricular function in two patients (aged 42 and 38 years) with stable angina and ischaemia reaction in the exercise ECG. In the first patient it was a short spur-like 80% narrowing. But percutaneous balloon angioplasty failed to change the angiographic appearance. In the other patient there was an eccentric, apparently elastic, 90% stenosis, about 10 mm long. Here, too, balloon angioplasty had failed. Subsequently directional coronary atherectomy in both patients achieved removal of the stenosis with lasting clinical improvement. Atherectomy should be considered in similar cases after failed balloon dilatation.

Adult↗

PubMed1991

[Neither propranolol nor the vasodilating beta-blocker carvedilol have a direct effect on coronary resistance vessels].

Seventeen patients with coronary heart disease were included in a double-blind randomized study. They received either 5 mg of carvedilol or 6 mg of propranolol intravenously. Heart rate, aortic pressure, mean coronary sinus pressure and coronary flow (thermodilution) were measured, and coronary resistance and rate-pressure product were calculated before and 15 min after the infusion, which lasted 10 min. Carvedilol lowered significantly (p less than 0.05) heart rate (mean 76 to 69/min), aortic pressure (mean 153/80 to 135/72 mm Hg), rate-pressure product (mean 117 to 93 mm Hg/min) and coronary flow (mean 114 to 94 ml/min). Coronary resistance and coronary flow related to rate-pressure product showed no significant change after carvedilol. Propranolol lowered heart rate (mean 76 to 64/min; p less than 0.05) and rate-pressure product (mean 109 to 96 mm Hg/min; ns). Aortic pressure, coronary flow, coronary resistance, and coronary flow related to rate-pressure product showed no significant change after propranolol. Thus, carvedilol lowered rate-pressure product more markedly than propranolol on account of its acute blood-pressure lowering effect. Neither drug seems to have a direct influence on coronary resistance vessels.

Adrenergic beta-Antagonists↗

PubMed1991

[Experiences with the Rashkind duct occluder].

In five patients, aged from 34 to 64 years, a persistent ductus arteriosus was occluded transvenously with a Rashkind umbrella occluder. The diameter of the ductus ranged from 3.6 to 9 mm, the pulmonary artery pressure ranged from 20/4 to 55/25 mm Hg. Four patients had calcifications of the ductus wall. In one patient with a very large ductus a first occluder embolized into the pulmonary artery and was removed together with the introducer sheath. The ductus was occluded with a second umbrella. However, there was a residual shunt in this patient. In all other patients the procedure was successful without residual shunt.

Adult↗

PubMed1991

[Trans-femoral ductus Botalli occlusion in patients over 60 years of age].

A persistent ductus arteriosus was occluded with an ivalon-plug introduced through the femoral artery in 14 patients over 60 years old (61 to 70 years). Two patients had previous surgery. The maximum left-to-right shunt was 53%, the maximum pulmonary artery pressure 54/24 mm Hg. In all patients ductus occlusion was successful and permanent. Bleeding at the puncture site in two patients could be stopped by manual compression. During a follow-up period of up to 5 years there were no instances of recanalization.

Aged↗

PubMed1991

[Main branch stenosis following aortic valve replacement].

Three patients developed left main stem stenosis within some months after aortic valve replacement. In all of them diagnosis was confirmed by angiography and bypass surgery was performed successfully. Left main stem stenosis is a rare complication of aortic valve replacement and is due to cannulation and perfusion of the coronary arteries. The mechanism is probably injury of the vessel wall due to the perfusion-catheter, followed by intimal hyperplasia. A similar mechanism is assumed for restenosis after transluminal coronary angioplasty.

Adult↗

PubMed1990

Influence of carvedilol and propranolol on coronary blood flow.

A total of 17 patients with angiographically proven coronary artery disease and at least one stenosis blocking greater than or equal to 70% of the left anterior descending or circumflex artery were included in a double-blind, randomized study. They received either 5 mg carvedilol or 6 mg propranolol intravenously. Heart rate, aortic pressure, mean coronary sinus pressure and coronary flow (thermodilution) were measured and coronary resistance and the rate-pressure product were calculated before and 25 min after injection. Carvedilol significantly (P less than 0.05) lowered the heart rate (mean, 76 to 69 beats/min), aortic pressure (mean, 153/80-135/72 mm Hg), rate-pressure product (mean, 117-93 mm Hg/min), and coronary flow (mean, 114-94 ml/min). Coronary resistance (mean, 0.97-1.07 mm Hg x min/ml) and coronary flow related to the rate-pressure product (mean, 1.0-1.02 ml/mm Hg) showed no significant change after carvedilol treatment. Propranolol lowered the heart rate (mean, 76-64/min; P less than 0.05) and rate-pressure product (mean, 109-96 mm Hg/min; not significant). Aortic pressure (mean, 145/72-147/74 mm Hg), coronary flow (mean 109-101 ml/min), coronary resistance (mean, 1.1-1.2 mm Hg x min/ml), and coronary flow related to the rate-pressure product (mean, 1.12-1.19 ml/mm Hg) showed no significant change after propranolol administration. Following single application, carvedilol lowered the rate-pressure product more markedly than did propranolol on account of its acute blood-pressure-lowering effect. No differences in the hemodynamic effects of carvedilol and propranolol were found. Neither drug seems to influence the adaption of coronary flow to myocardial oxygen demand.

Adrenergic beta-Antagonists↗

PubMed1990

[Effect of the calcium antagonist nisoldipine on coronary circulation and myocardial ischemia in temporary coronary occlusion].

Sixteen patients undergoing PTCA of a significant lesion of the left anterior descending coronary artery received either 0.3 mg nisoldipine or placebo intravenously. Immediately before and during balloon inflation the following parameters were measured: aortic pressure, post-stenotic pressure, coronary occlusion pressure, diastolic pulmonary artery pressure, coronary sinus flow (thermodilution), and intracoronary ECG. After placebo there were no statistically significant changes. Nisoldipine led to a decrease in aortic pressure from 109 +/- 12 to 93 +/- 11 mm Hg (p less than 0.05) before, and from 103 +/- 14 to 92 +/- 8 mm Hg (NS) during balloon inflation. In contrast, coronary occlusion pressure remained unchanged. Heart rate increased from 80 +/- 13 to 96 +/- 16/min before (p less than 0.05), and from 87 +/- 18 to 97 +/- 17/min during balloon inflation (NS). Coronary sinus flow was increased from 95 +/- 16 to 116 +/- 13 ml/min before balloon inflation (p less than 0.01), and from 70 +/- 25 to 86 +/- 26 ml/min during balloon inflation (NS). ST-segment depression or elevation, severity of angina pectoris, and the diastolic pulmonary artery pressure remained unchanged. Thus, 0.3 mg nisoldipine led to a peripheral vasodilatation. While the aortic pressure decreased, coronary occlusion pressure remained unaffected. This could be explained by a marked dilatation of collateral vessels due to nisoldipine. However, myocardial ischemia remained unaffected as a result of the constant coronary occlusion pressure.

Adult↗

PubMed1989

[Piretanide in chronic and acute decompensated heart failure. Effect on hemodynamics and vasoactive hormones].

Eight patients with chronic heart failure classified as NYHA class II to III (group 1) and nine patients with acute decompensated heart failure classified as NYHA class IV (group 2) were treated with piretanide at a dosage of 12 mg administered intravenously. In both groups the level of prostaglandine PGE2 as well as plasma renine activity significantly increased prior to the onset of diuresis. The percentage increase was more pronounced in group 1 which had lower baseline values. With a time-lag, the norepinephrine plasma level also increased significantly. During the first 30 minutes there was only little effect on blood pressure, pulmonary artery pressure and cardiac output in patients with chronic heart failure (group 1). Only after 60 minutes there was a significant decrease in mean pulmonary artery pressure (from 39 +/- 17 to 33 +/- 18 mm Hg; p less than 0.05). In patients with acute decompensated heart failure (group 2) piretanide led to a significant reduction in mean pulmonary artery pressure (from 42 +/- 13 to 37 +/- 12 mm Hg; p less than 0.05) within 15 minutes after administration, i.e. even prior to the onset of diuresis. Thus, the administration of piretanide had a positive effect on hemodynamics in patients with chronic as well as in patients with acute decompensated heart failure. Significant improvement prior to diuresis onset, however, was only found in patients with acute decompensated heart failure. These effects may be explained by a stimulation of prostaglandines which promote vasodilation. They are increased by the diuresis.(ABSTRACT TRUNCATED AT 250 WORDS)

6-Ketoprostaglandin F1 alpha↗

PubMed1989

[Aortic aneurysm after dilatation of aortic isthmus stenosis].

An aneurysm in the region of the dilatation occurred in two of 23 patients (a 17-year-old boy and a 29-year-old woman) three and one years, respectively, after balloon dilatation for coarctation of the (thoracic) aorta. The aneurysm in the boy was small (18 mm diameter) and he was symptom-free so that no operation is as yet indicated. But the woman had progressively increasing backache after physical exertion and the aneurysm was 4 cm in diameter. Therefore, the aneurysm and coarcted segment were resected and a Dacron prosthesis interposed. As the ultimate value and risk of balloon dilatation of coarctation of the aorta cannot as yet be definitively judged, all patients should be carefully and repeatedly examined over a longer period.

Adolescent↗

PubMed1989

[Basic therapy of chronic heart failure with digitalis or diuretics?].

Sixteen patients in heart failure and sinus rhythm were, after a four-week treatment-free period, randomly assigned to receive, for four to six weeks, either a diuretic combination (hydrochlorothiazide + triamterene) or a digitalis glycoside. Subsequently the treatment was exchanged between the two groups. Without treatment nine patients were in stage II (New York Heart Association classification), seven in stage III. Pulmonary wedge pressure at rest was 27 +/- 14, on exercise 32 +/- 8 mm Hg, cardiac output 5.3 +/- 1.0 at rest and 7.8 +/- 2.3 l/min on exercise. Digitalis glycosides improved symptoms by one stage in three of 16 patients. All objective measures showed slight but not significant improvement. Diuretic treatment improved symptoms in five patients, while heart size and echocardiographically measured ventricular volume decreased slightly. Cardiac output decreased at rest, but not significantly, and on exercise not at all. Pulmonary arterial pressure (21 +/- 9 mm Hg), pulmonary wedge pressure (13 +/- 7 mm Hg) and pulmonary artery pressure on exercise (39 +/- 11 mm Hg) were significantly lower on diuretics than without treatment. The results support the primary use of diuretics in the treatment of chronic heart failure.

Aged↗

PubMed1989

[Catheter valvuloplasty in mitral valve stenosis].

Balloon dilatation of the mitral valve was performed, trans-septum via the femoral vein or retrogradely via the femoral artery, in 20 patients, aged 31-65 years, with post-rheumatic mitral stenosis. Haemodynamically insignificant mitral regurgitation occurred in two patients. In one patient a permanent atrial septal defect was produced by the transseptal puncture. In a fourth patient severe mitral regurgitation occurred which required operation. There were no other serious complications. No dilatation was possible in three patients for technical reasons. Successful dilatation was achieved in 16 of the 20 patients. The end-diastolic transvalvular pressure gradient was reduced from 12 +/- 5 to 4 +/- 3 mm Hg. At follow-up, after 3-6 months (12 patients) or after 1-1.5 years (5 patients), in one instant after a second dilatation, a lasting good result was confirmed, the mean end-diastolic gradient being 4 +/- 3 mm Hg.

Adult↗

PubMed1989

Restenosis is a common feature of the angiographic follow-up after balloon valvoplasty of calcified aortic stenoses.

Balloon dilatation of calcified aortic stenosis was attempted in 12 patients, 6 men and 6 women, aged 38-82 years. Two patients underwent emergency surgery because of myocardial injury or pericardial tamponade. One patient with severe depressed left ventricular function in whom the procedure was attempted in cardiogenic shock died during the procedure. One patient experienced severe aortic insufficiency after dilatation. The remaining pressure gradient was higher than 50 mm Hg in another patient. Seven dilatations were considered to be successful with a remaining pressure gradient below 50 mm Hg and a mean gradient reduction of 53 mm Hg. In one of these 7 patients, who suffered from severe heart failure, valvoplasty had been carried out to make aortic valve replacement possible. The operation was performed 2 weeks later without complications. Five of 6 patients treated medically after successful valvoplasty had restenosis within 3 to 12 months. One of them exhibited a good result at 3 months but severe restenosis after one year. It is concluded that balloon valvoplasty of calcified aortic stenosis cannot be considered an alternative to surgery. If, however, left ventricular function improves after successful valvoplasty, valve replacement will then carry less risk.

Adult↗

PubMed1989

Coronary stenosis dilation by low dose intravenous nitroglycerin.

In a randomized double-blind study, 40 patients with coronary heart disease received either 0.025 mg nitroglycerin or placebo intravenously. Before and 2-3 min after injection, the aortic and left ventricular pressures were recorded and coronary angiography was performed. Mean heart rate, systolic and diastolic aortic pressure, left ventricular filling pressure and the pre- and poststenotic coronary artery diameters, as well as the diameters of representative distal coronary artery segments showed no significant changes. Coronary artery stenosis diameters remained unchanged after placebo (1.01 +/- 0.5 to 1.13 +/- 0.49 mm; n.s.) but increased significantly after nitroglycerin from 1.15 +/- 0.68 to 1.32 +/- 0.73 mm (P less than 0.01). Since it has been demonstrated, on the other hand, that the same dose of nitroglycerin reveals antianginal activity, it can be hypothesized from these results that dilatation of coronary stenoses plays an important role in the antianginal action of nitroglycerin. Strong haemodynamic effects do not appear to be a prerequisite of the beneficial effects of nitroglycerin.

Adult↗

PubMed1989

Long-term results of percutaneous pulmonary valvuloplasty in adults.

We performed percutaneous balloon valvuloplasty of the pulmonary valve in 24 patients (aged 17 to 72 years) and in two juvenile patients. There were no major complications. In almost all the patients the procedure resulted in a successful pressure gradient reduction from a mean of 92 +/- 36 mmHg to 43 +/- 19 mmHg (P less than 0.01). In seven patients there was a residual pressure gradient greater than 50 mmHg which, however, decreased in all patients within the following 3-12 months due to a decrease in subvalvular muscular hypertrophy (from a mean of 70 to 35 mmHg). No restenosis was observed. Only one patient, who had calcified valve leaflets, developed pulmonary insufficiency and this was of only minor haemodynamic importance. Balloon dilatation of the pulmonary valve can be considered a technique with a high success rate and low complication rate even in the elderly. Good long-term results support this approach as the first choice in the treatment of pulmonary valve stenosis.

Adolescent↗

PubMed1989

[Anti-angina and coronary dilating effect of low-dose nitroglycerin].

Fourteen patients with typical exercise-induced angina and ST-segment depression received 0.025 mg nitroglycerin intravenously or placebo directly before exercise testing in a double-blind cross-over study. The sum of ST-segment depressions during stress and recovery was 12.8 +/- 4.8 mm after placebo and 8.9 +/- 4.6 mm after nitroglycerin (p less than 0.001). The symptom-free exercise time increased from 3.1 +/- 1.4 to 4.3 +/- 1.9 min (p less than 0.1), whereas severity of angina during exercise decreased significantly (p less than 0.05) after nitroglycerin. There was no influence on either heart rate or blood pressure. In a second randomized double-blind study, 40 patients with coronary heart disease received either 0.025 mg nitroglycerin or placebo intravenously. Before and 2 min after injection the aortic and left ventricular pressures were recorded and coronary angiography was performed. Mean heart rate, blood pressure, left ventricular filling pressure and pre- and poststenotic coronary artery diameter, as well as the diameters of representative distal coronary artery segments showed no significant changes. Coronary artery stenosis diameters remained unchanged after placebo, but increased significantly after nitroglycerin from 1.15 +/- 0.68 to 1.32 +/- 0.73 mm (p less than 0.01). It can be hypothesized from these results that dilatation of coronary stenosis plays an important role in the antianginal action of nitroglycerin. Coronary artery stenoses seem to be more sensitive to nitroglycerin than are other vessel segments.

Angina Pectoris↗