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Biomedical subjects

H Landgraf

Publications and source records attributed to H Landgraf.

At least 19 recordsLinked to original sources
PubMed1992

[Reopening chronic arterial occlusions].

Chronic complete occlusions still represent the major technical limitation of percutaneous transluminal balloon angioplasty, both in peripheral and coronary vessels. The clinical use of low speed rotational angioplasty (ROTACS) started in 1986 for the peripheral and in 1987 for the coronary vessels, and has already become part of the clinical routine in several centers. Up to now, more than 300 patients with peripheral and more than 200 patients with coronary occlusions were treated in Frankfurt. In peripheral occlusions the acute success rate was more than 80% if used as the first attempt; after failure of conventional techniques still more than 60% of the vessels could be recanalized successfully. In addition to occlusions of the arteries of the lower limbs, the indication now includes the iliac artery and several other indications are under investigation. In each of the patients with chronic coronary occlusions an attempt with conventional techniques had failed before. Following a learning curve, which was also influenced by a better understanding of morphological preconditions, the acute success rate has now reached 70%. Both in patients with peripheral and those with coronary occlusions no deaths occurred. First angiographically documented long-term results in both indications are comparable to conventional balloon angioplasty. It is concluded that the use of low speed rotational angioplasty (ROTACS) can improve the results of nonoperative invasive treatment, both in peripheral and in coronary arteries.

Angiography↗
PubMed1991

[Pain in chronic arterial occlusive disease--the effect of improved macrocirculation on pseudo-radicular irritation].

In chronic obliterating arteriopathy the maximum walking distance does not correlate well with the ankle arm index of arterial pressure measured by Doppler ultrasound. Beside reduced macrocirculation and microcirculatory maldistribution in skeletal muscle, pseudoradicular irritation was established as a relevant factor for the onset of pain during walking. The present study investigates the influence of the macrocirculation on hyperalgesia at rest in intermittent claudication. In 35 patients with chronic obliterating arteriopathy of the lower limbs (stage II according to Fontaine) the ankle/arm index of arterial pressure and the walking tolerance, as well as the pain at rest on applying pressure to the calf muscles were determined before and 3 weeks after percutaneous transluminar angioplasty (PTA). All 3 parameters improved after dilatation. Improved macrocirculation leads not only to a decreased production and improved clearance of pain-inducing metabolites in muscle tissue, but also--through a decrease of sympathetic stimulation of the muscle--to an elevation of the pain threshold. Apart from the reduction in pain-inducing metabolites, an absence of booster effects on pseudoradicular irritation and the regeneration of sensitive cutaneous afferents with resultant inhibition of reflex pain development are considered as possible factors in the achievement of pain relief following PTA.

Angioplasty, Balloon↗
PubMed1991

[Hemodilution in acute cerebral ischemia].

Hemodilution therapy in acute cerebral infarction is still a controversial issue. This is mainly due to the different results achieved in clinical studies so far. Criticism, however, is justified in some points. The reason for the different results of the studies is very likely to be the selection of the patients, i.e. the poor differentiation of acute cerebral infarctions. In addition, the different therapy regimens applied must be taken into account. Thus, several questions arise in connection with the clinical application and the further investigation of this therapy which have so far been answered not at all or only in part. Since there is at present no appropriate alternative treatment for acute cerebral infarction, hemodilution is most likely to remain an important therapy in this indication.

Blood Flow Velocity↗
PubMed1989

[Rotational angioplasty--recanalization of chronic arterial occlusion using a slowly rotating catheter. Clinical results with 100 patients].

Between December 1986 and January 1989, 100 patients with chronic occlusions of peripheral arteries were treated with the new technique of low speed rotational angioplasty. This uses a relatively thick, flexible and blunt catheter, which is driven by an electric motor (100 to 200 r.p.m.). The success rate in the superficial femoral and popliteal arteries of the initial intervention for occlusions less than 10 cm was 90%, for occlusions of less than 10 cm, it was 80%. Occlusions on which conventional techniques had failed were successfully recanalized in 65%. Recanalisation was also successful in seven out of 12 patients with occluded iliac arteries. There were no perforations or other serious complications. It is concluded that the new method is particularly effective and safe for recanalisation of chronic vascular occlusions and should also be considered for cases which previously could only be treated surgically.

Adult↗
PubMed1989

Low-speed rotational angioplasty in chronic peripheral artery occlusions: experience in 83 patients. Work in progress.

Between December 1986 and October 1988, 83 patients with chronic peripheral artery occlusions were treated with a new technique. In 56 patients, the superficial femoral artery was completely occluded; in 21 patients, the popliteal artery; and in six patients, the iliac artery. The length of occlusion ranged from 5 to 35 cm (mean, 12.5 cm). The duration, estimated by history, was 5-48 months (mean, 16.5 months). In seven patients, durations of 6-36 months were documented angiographically. A flexible, blunt, motor-driven rotating catheter was introduced through an 8-F sheath, and rotational angioplasty was performed at low speed (up to 200 rpm). In 49 of 60 (82%) patients in whom this new technique was used as the primary intervention, the occlusions were successfully reopened. In 23 patients in whom conventional methods had failed more than 4 weeks earlier, the success rate for rotational angioplasty was 67% (12 of 18 patients); when the time interval was less than 4 weeks, only one of five patients was treated successfully. In none of the 83 patients did a perforation occur. This new technique can reopen chronic artery occlusions with a high degree of success and without the danger of vessel-wall perforation, even after failure of conventional techniques.

Adult↗
PubMed1989

[Rotation angioplasty--clinical experiences in 83 patients with chronic arterial vascular occlusion].

Chronic, total vascular occlusion represents the limit for use of balloon dilatation. Occlusions of the superficial femoral artery and popliteal artery of more than 10 cm in length have a low recanalization rate of 50 to 60% with conventional angioplasty. In iliac artery occlusions, in addition to a high rate of complications, the recanalization rate is only about 30 to 40%. Starting in 1984, we developed a slowly rotating (100 to 200 r.p.m.), electrically-driven, flexible catheter with a blunt tip, inside lumen and outer diameter of 2.2 mm for the purpose of recanalization (Figure 1). The theoretical basis was that such a catheter would seek the soft occluding thrombus as the path of least resistance. Since 1986, the procedure has been carried out in 56 patients with occlusion of the superficial femoral artery, 21 with occlusion of the popliteal artery and six with occlusion of the iliac artery. The duration of occlusion ranged between five and 48 months and the length of the occlusions between 5 and 35 cm (mean 12.5 cm); the patients were in Fontaine stage II and IV, the ankle arm-index ranged between 0 and 0.86 (mean 0,51). After antegrade or retrograde puncture of the common femoral artery and intra-arterial injection of 5,000 units of heparin, the rotation catheter was advanced through an 8F sheath through the occlusion by means of slow rotation (Figure 2). After contrast medium injection to document the intraluminal position of the catheter and the catheter exchange over a 0.35'' wire, the channel created was dilated.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1988

Results of low speed rotational angioplasty for chronic peripheral occlusions.

After experimental investigation using postmortem human arteries, 19 patients with chronic peripheral artery occlusions were treated with a new angioplasty technique between December 1986 and October 1987. In 17 patients the superficial femoral artery and in 2 patients the popliteal artery were completely occluded. The length of the occlusions ranged between 5 and 25 cm (mean 11). The duration--estimated according to patients' history--was 5 to 48 months (mean 17). In 5 patients, durations of up to 30 months had been documented by angiography. A flexible, blunt, motor-driven rotating catheter was introduced through an 8 or 9Fr sheath and rotational angioplasty was performed at low speeds (up to 200 rpm). In 11 of 14 patients in whom this new technique was used as the primary intervention, the occlusions could be successfully reopened. In 2 patients after failure of conventional techniques the rotating catheter could not bypass the preexisting dissections in the same intervention. In 2 of 3 further patients after failure of conventional techniques the occlusions could be successfully reopened in a second intervention after several weeks. In none of the 19 patients did a perforation occur. It is concluded that with the new technique chronic peripheral artery occlusions can be reopened with a high success rate and without the danger of arterial wall perforation. The method can also be used in patients in whom conventional techniques have failed.

Adult↗
PubMed1988

Influence of videofilm-induced emotional stress on the flow properties of blood.

The hemorheologic effects of emotional stress induced by a videofilm were investigated in 10 healthy volunteers. Blood samples were obtained from the antecubital vein before, during, and after the end of the videofilm. Blood pressure and heart rate were simultaneously measured. There was a statistically significant increase in blood and plasma viscosity during and immediately after the end of the videofilm, which correlated with an increase in plasma catecholamine concentrations. This hemorheologic behavior can be explained as a result of an endogenous hemoconcentration that takes place if the Starling equilibrium of intravascular vs extravascular fluid is changed. These observations could lead to new aspects of the pathophysiology of acute myocardial infarction initiated by severe emotional stress.

Adult↗
PubMed1987

[Treatment of hyperkinetic heart syndrome with alinidine and propranolol].

A hyperkinetic heart syndrome has been diagnosed in 10 patients by clinical investigation and right-heart catheterization at rest and during exercise. Subsequently, the patients received 3 X 40 mg alinidine, and 2 X 40 mg propranolol and placebo, each for 2 weeks in a double-blind crossover study. Heart rate at rest (P less than 0.05) and during exercise (P less than 0.001) decreased significantly under alinidine and propranolol to the same extent (control, 83/170; alinidine, 68/146; propranolol, 73/139; placebo, 83/162 beats per min). Lower limb flow at rest and after exercise, measured by plethysmography, as well as left-ventricular fractional shortening and mean velocity of circumferential fiber shortening, measured by echocardiography, decreased insignificantly. Sedation and a dry mouth occurred in six patients under alinidine, while fatigue and cold hands and/or feet were reported by five patients under propranolol. Thus, alinidine may be used as an alternative to beta-blocking in the treatment of the hyperkinetic heart syndrome.

Adult↗
PubMed1987

Acute hemodynamic effects of the vasodilating and beta-blocking agent carvedilol in comparison to propranolol.

In a randomized double-blind study, oral doses of 50 mg carvedilol were compared to 40 mg propranolol in 16 male patients with coronary heart disease (12 without significant stenosis after percutaneous transluminal coronary angioplasty) at rest, during and after exercise, and before and 80 min after drug application. Systemic and pulmonary pressures, heart rate, cardiac index, and lower limb blood flow were measured, and systemic and pulmonary resistances calculated. Carvedilol does not lead, as the classical beta-blocker propranolol does, to an increase in systemic or pulmonary resistance, nor to a decrease in cardiac output, or to an increase of the pulmonary capillary wedge pressure during exercise. In contrast to propranolol, the postexercise lower limb blood flow has increased significantly. The differences in action between the two beta-blockers can be explained by the vasodilating properties of carvedilol. Due to these acute effects, carvedilol may be of advantage compared to propranolol in the treatment of peripheral occlusive artery disease, hypertension, and coronary vasospasm.

Adrenergic beta-Antagonists↗