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Biomedical subjects

F Mahler

Publications and source records attributed to F Mahler.

At least 91 records · Page 5Linked to original sources

[Recent instrumental developments in percutaneous transluminal angioplasty (PTA)].

In addition to the balloon-catheter for PTA a number of new devices have been developed in recent years. Among them the most outstanding are laser beam application, mechanical devices for recanalization and endoprostheses for stenting of the vessels. The initial fascination by laser technique in PTA has given way to a matter-of-fact appreciation of the method. Up to now no available laser system achieves better clinical results than conventional PTA in the long run. Although there is much potential in the laser principle, it still is to be regarded as experimental. As for mechanical devices the fast rotating Kensey-catheter has not been proven superior to balloon PTA in our hands neither to remove organized or fresh thrombotic occlusive matter. A slowly rotating catheter (Rotacs) facilitates primary recanalisation of long occlusions prior to balloon dilatation. Atherectomy by the Simpson-catheter provides samples for histological studies but is indicated only in special situations. Numerous other mechanical percutaneous endarterectomy devices are under development, but clinical long term evaluation is not yet available. Vascular stents - self expandable or balloon expandable systems - may serve to keep the newly dilated arterial lumen open and to prevent late recurrences. While in larger vessels such as iliac arteries or aorta good long-term results after insufficient PTA were shown, other indications are still experimental. For all of these newer technologies both their relative effectiveness and the extent to which they may compare with or complement balloon PTA remain to be determined.

Angioplasty, Balloon↗

[The diabetic foot].

The socio-economic, medical and psycho-social consequences of lower-limb injuries in diabetic patients are enormous. The risk of lower extremity amputation is 15 times greater in diabetic patients than in the age-matched non-diabetic population. About 1000 diabetic patients undergo a disabling amputation annually in Switzerland. Implementation of appropriate educational and foot-care programmes by motivated pluridisciplinary teams may reduce major amputations by as much as 50%. Regular examination of the feet of diabetic patients, therefore, deserves the same priority in diabetes care as control of the optic fundus and of kidney function, but unfortunately this is seldom the case. These guidelines summarize the physiopathology, the diagnosis and the treatment of diabetic foot problems. Emphasis is placed on simple preventive measures which should help protect the majority of high-risk patients.

Diabetes Complications↗

Do vasospasms provoke ocular diseases?

Vasospasms in the eye are often combined with digital vasospasms, as can be diagnosed with a nailfold capillaroscopic local cooling test. In 16 patients with a history of cold hands and feet the presence of peripheral vasospasms without any underlying disease was demonstrated by means of nailfold video-capillaroscopy. These patients showed the phenomenologic diagnosis of low-tension glaucoma with visual field defects characteristic of glaucoma even though intraocular pressure above 21 mmHg was excluded. The visual field defects were not homonymous, indicating a prechiasmal location of the vascular disturbance. Ocular vasospasms cause visual field damage that can be aggravated or provoked by cooling one hand in cold water and that often improves after treatment with the calcium channel blocker nifedipine. The results suggest that vasospasms not only are present in Raynaud's disease, migraine, and Prinzmetal's variant angina but also may be an important factor in the genesis of low-tension glaucoma. This is a new finding and may be related to a general vasospastic syndrome.

Adolescent↗

[Vascular endoprosthesis of femoro-popliteal occlusive disease].

A self-expanding vascular endoprosthesis (wall stent) was implanted in 26 patients with femoropopliteal occlusive disease following recurrent stenosis or occlusion after percutaneous angioplasty. Implantation was successful in all cases and there were no complications. Five of the 26 patients developed a thrombosis in the first nine days; in four of these, thrombolysis was successful. Patency rate after one month was 96%, after three months 95%, after six months 85% and after nine months 87%. In order to prevent thrombosis after implantation, anticoagulant therapy is indicated. Poor distal flow encourages intimal hyperplasia and therefore recurrences.

Adult↗

Increased peripheral vasoconstrictor reaction upon local cold in patients with coronary heart disease.

A local cold exposure test of the nailfold capillaries produces a typical flow stop reaction in 88% of patients with Raynaud's phenomenon. We applied this test to 12 patients with variant angina and compared the results with the findings in 2 control groups of 12 patients each, matched for age and sex: One group with chronic stable angina and one without heart disease. We found a flow stop with cold exposure in 9/12 patients with variant angina (mean duration 24 s), in 6/12 patients with chronic angina (mean 11 s), and in 1/12 normal controls without heart disease (mean 1 s). The frequency and duration of the flow stop was significantly higher in patients with variant angina (p = 0.002) and in patients with chronic stable angina (p = 0.02) than in normal controls. Patients with variant angina also tended to have an increased frequency and longer duration of the flow stop than those with chronic stable angina (p = 0.09). Administration of sorbidilate preparations and nifedipine resulted in a decrease of the mean flow stop duration from 23.5 to 10.8 s in patients with variant angina (p = 0.03). The strong association of a vasoconstrictive reaction in finger microcirculation and coronaries in patients with variant angina suggests a vasospastic tendency with manifestation in different vascular regions.

Adult↗

Local cooling test for clinical capillaroscopy in Raynaud's phenomenon, unstable angina, and vasospastic visual disorders.

A local cooling test produces a typical flow stop reaction in nailfold capillaries in 88% of patients with Raynaud's phenomenon, but only in 15% of healthy controls. A stop reaction occurred in 9 of 12 patients with Prinzmetal variant angina, exceeding significantly that in 2 of 12 matched control subjects. Also in patients with reversible visual disorders presumably due to vasospasm, the test resulted in a stop reaction in 16 of 25 cases exceeding that in control. In both of these patient groups the cooling test as well as the symptoms reacted favorably to nifedipine. Thus, the local cold exposure test appears to be useful for objective clinical examination not only of patients with Raynaud's phenomenon but also of patients with vasospastic syndromes such as variant angina and visual disorders.

Adult↗

[Clinical aspects and treatment of acute arterial occlusion].

163 patients underwent surgery for acute ischemia of the lower extremity between 1982 and 1986. Thrombosis was present in 50 cases and embolism in 113. Half of the patients with thrombosis showed signs of chronic occlusive disease of the arteries (intermittent claudication); in the latter group 2/3 of the patients had atrial fibrillation and 1/4 coronary heart disease. For embolism Fogarty-catheter clot extraction was performed, mainly under local anesthesia. This procedure is easy to perform even under emergency conditions (mortality 10%, amputation rate 8%). In contrast, the surgical procedure in thrombotic occlusion was more demanding (mortality 4%, amputation rate 16%) and in the case of severe ischemia had to be carried out on an emergency basis. In case of less severe ischemia the treatment consisted in initial heparinization and elective revascularization when the patient was stabilized. A new therapeutic approach involving local catheter thrombolysis, catheter clot aspiration and balloon dilatation is presented. The combined catheter intervention produces good results in 70% of patients, particularly those with femoral thrombosis.

Acute Disease↗

[Practical importance of capillary microscopy].

Vital capillaroscopy has been successfully used for many years to study the microcirculation of human skin capillaries. The presence of typical capillary abnormalities is helpful in distinguishing scleroderma from other connective tissue diseases. Application of a local cold exposure test to finger nailfold capillary microscopy reveals the functional difference between normal subjects and patients with Raynaud's syndrome on the level of the microcirculation. Transcutaneous intravital fluorescence videomicroscopy may be helpful in the sometimes difficult differential diagnosis of lower limb edema. Microlymphangiography offers a new approach to depiction of the intravital anatomy of human lymphatic skin capillaries. Further the technique of intravital fluorescence videomicroscopy provides a noninvasive method of studying morphologic and functional abnormalities in diabetic microangiopathy.

Capillaries↗

Cutaneous spider nevi in liver cirrhosis: capillary microscopical and hormonal investigations.

Nailfold capillary microscopical and hormonal investigations were carried out in 25 patients with cirrhosis of the liver and in 20 age- and sex-matched controls. Several structural and functional capillary microscopical parameters were significantly different between the group of cirrhotics as a whole and the controls; no capillaroscopic feature helped to distinguish cirrhotics with spiders from those without. Serum estradiol and total testosterone were comparable in cirrhotics and controls; free serum testosterone was reduced in male cirrhotics, particularly in cirrhotics with spider nevi. The estradiol/free testosterone ratio was highest in male cirrhotics with spiders. Cirrhosis, thus, leads to both structural and functional effects on the cutaneous capillary system whether or not spider nevi are present. The presence of spider nevi is accompanied by an increased serum estradiol/free testosterone ratio in male cirrhotics. It remains to be determined whether the hormonal alterations described do indeed play a role in spider nevi formation.

Adult↗

[The use of calcium antagonists in the treatment of ocular circulation symptoms in the framework of a vasospastic syndrome].

In a number of patients with etiologically unexplained visual field loss, a vasospastic syndrome was found with the aid of capillaroscopic local cooling test on the fingers. After therapy with calcium entry blockers the visual field of the patients with vasospastic syndrome underwent a marked and statistically significant improvement. The control group showed a slight but statistically insignificant tendency towards improvement.

Calcium Channel Blockers↗

The relationship between digital and ocular vasospasm.

The study evaluates whether ocular vasospasms, as determined by visual field tests, are related to a patient history of cold hands and to microscopic findings of the nailfold capillaries. The visual fields of patients with ocular vasospasms may deteriorate after exposing one hand to cold water and may improve after administration of nifedipine. Local cooling of the fingers of patients with vasospastic tendencies results in a significant reduction of capillary blood flow, typically down to a standstill of several seconds. The study reveals a statistically significant relationship between a patient history of cold hands and both the outcome of the perimetric and capillaroscopic tests. Furthermore, the perimetric results correlated significantly with the capillaroscopic results.

Adolescent↗

Femoro-popliteal artery thrombolysis with intra-arterial infusion of recombinant tissue-type plasminogen activator--report of a pilot trial.

Recombinant tissue-type plasminogen activator (rt-PA) was infused at a rate of 10 mg/h into 50 thrombosed femoral and popliteal arteries. Patency was restored in 43 but a secondary angioplasty led to 2 reocclusions and in 3 patients early rethrombosis occurred. A favourable clinical result was thus obtained in 38 patients (76%). Thirteen bleeding complications occurred in 10 patients, mainly haematomas at puncture sites. One patient required blood transfusion for gastro-intestinal bleeding from a previously unknown ulcer. The angiographic recanalisation rate in 16 patients who received a slower infusion of rt-PA (5 or 3 mg/h) was 94% and the clinical success rate in this series was 81%. However, the incidence of bleeding complications was not decreased by the slower infusion rate. The data obtained confirm the feasibility of rt-PA thrombolysis in peripheral arterial thrombosis and warrant a comparative study with streptokinase.

Angioplasty, Balloon↗