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Biomedical subjects

R Karnik

Publications and source records attributed to R Karnik.

At least 37 records · Page 2Linked to original sources
PubMed1993

Intra-operative transluminal angioplasty of the supra-aortic vessels.

Intra-operative transluminal angioplasty of supra-aortic vessels was performed in 9 patients. All subjects had lesions which were considered difficult or impossible to operate upon. In 2 patients a proximal occlusion of the left subclavian artery was dilated. Seven subjects showed severe stenoses of the supra-aortic vessels: common carotid artery: 1, internal carotid artery: 2, external carotid artery: 1, external carotid artery prosthetic graft: 1, brachiocephalic trunk: 1, vertebral artery: 1. All patients suffered from symptoms which corresponded to the site of the lesions in question. Intra-operative angioplasty was primarily successful in all 9 patients. Re-occlusion occurred within a few days in both patients who underwent angioplasty of the subclavian artery. Six of the seven subjects with stenotic lesions remained free of symptoms and of restenosis. In the case of dilatation of a prosthetic graft of the external carotid artery asymptomatic occlusion developed within 8 weeks. In selected cases intra-operative angioplasty is a potentially valuable alternative in the treatment of surgically inaccessible lesions of the supra-aortic vessels.

Adult↗
PubMed1993

[Aortocoronary bypass operation or percutaneous transluminal coronary dilatation in patients over 70 years of age?].

On account of improved outcome an increasing number of patients more than 70 years old have undergone aortocoronary bypass grafting or percutaneous transluminal coronary angioplasty over the past years. Elective coronary bypass surgery carries a risk in the range of 5 to 10% hospital mortality among this age group. However, excellent long term results are in favour of surgery in carefully selected patients. Major indications are patients with extended areas of myocardial ischemia due to left main stem or proximal triple vessel disease. Overall results of PTCA are, likewise, somewhat less satisfactory in geriatric patients than in younger ones. With careful selection of patients, however, morbidity and mortality of this intervention is low. Excellent indications for PTCA are short, concentric, non calcified single or multiple vessel lesions in symptomatic patients with good ventricular function. In patients with angina refractory to medical treatment who carry an increased risk of surgery, PTCA may be worthwhile even if the coronary morphology is less promising (type B or C lesion).

Aged↗
PubMed1993

[Aortic valve stenosis in the aged--replacement or dilatation?].

In patients with severe symptomatic aortic stenosis the prognosis is very poor (1 year mortality rate 54%). Percutaneous transluminal aortic valvuloplasty shows a primary success rate of 86% and an in hospital mortality rate of 7%. However, within 6 to 12 months in almost all patients restenosis occurred. 23% of the patients died within this time range. 13 subjects with restenosis underwent redilatation or valve surgery. Aortic valve surgery is the treatment of choice in this setting. The method demonstrates also in elderly patients a relatively low early mortality rate and excellent long term results. Patients in NYHA stage IV, with severe coronary heart disease and with impaired left ventricular function (LVEF < 50%) show a 2.5 to 3.6 times increased early postoperative mortality rate. In these patients valvuloplasty may be performed as a palliative therapy or as a bridging procedure to aortic surgery. Aortic valvuloplasty may be indicated further in patients with reduced general conditions or severe secondary diseases.

Aged↗
PubMed1992

Transcranial Doppler sonography monitoring of local intra-arterial thrombolysis in acute occlusion of the middle cerebral artery.

BACKGROUND AND PURPOSE: The aim of this study is to report on the use of transcranial Doppler ultrasonography as a noninvasive diagnostic monitoring tool during local intra-arterial thrombolysis in a patient with acute embolic occlusion of the middle cerebral artery. CASE DESCRIPTION: We describe a 41-year-old woman with mitral valve stenosis suffering from embolism of the middle cerebral artery. Local thrombolysis was performed with tissue plasminogen activator at a dosage of 0.05 mg/kg/hr. Progress of the thrombolysis was monitored by transcranial Doppler. The steps of recanalization could be ascertained by transcranial ultrasound showing a hemodynamically relevant residual stenosis after the first 120 minutes and complete patency of the M1 segment of the middle cerebral artery 180 minutes later. One branch of the middle cerebral artery still showed a filling defect. CONCLUSIONS: Our report demonstrates the potential usefulness of transcranial Doppler monitoring during thrombolysis of a proximal occlusion of the middle cerebral artery for guiding the treatment by assessing the reperfusion of the obstructed artery.

Acute Disease↗
PubMed1992

Evaluation of vasomotor reactivity by transcranial Doppler and acetazolamide test before and after extracranial-intracranial bypass in patients with internal carotid artery occlusion.

BACKGROUND AND PURPOSE: The aim of this trial was to evaluate the effectiveness of extracranial-intracranial bypass with respect to vasomotor reactivity in patients with internal carotid artery occlusions and absent vasomotor reactivity, comparing them with a control group treated conservatively. METHODS: To test vasomotor reactivity in 104 patients with unilateral occlusion of the internal carotid artery, we measured blood flow velocity in the middle cerebral artery by transcranial Doppler sonography both at rest and after injection of acetazolamide. Among the 39 patients who failed to show increased mean blood flow velocity after the acetazolamide test distal to an occluded internal carotid artery by greater than or equal to 10%, 14 subjects subsequently underwent extracranial-intracranial bypass surgery (group A) and 14 age- and sex-matched subjects in whom no such procedure was done composed the control group (group B). Follow-up examinations were performed 3-6 months postoperatively and in the control group 3-6 months after initial examination. RESULTS: Baseline values of the mean blood flow velocity at rest on the affected side were reduced in both groups compared with the contralateral healthy side (group A, 46.0 +/- 15.1 cm/sec; group B, 48.1 +/- 16.7 cm/sec) and revealed only a marginal increase after acetazolamide. The contralateral side showed a normal blood flow velocity at rest and an adequate response to acetazolamide in both groups. On the follow-up examination group A demonstrated a normalized vasodilatory capacity. Blood flow velocity increased significantly after acetazolamide from 41.9 +/- 13.1 cm/sec to 53.5 +/- 16.0 cm/sec (p less than 0.002). In group B, the compromised vasomotor reactivity remained unchanged. CONCLUSIONS: Our results demonstrate that transcranial Doppler sonography together with the acetazolamide test can identify subjects with reduced vasomotor reactivity distal to an occluded internal carotid artery, who may improve hemodynamically by an extracranial-intracranial bypass.

Acetazolamide↗
PubMed1992

[Transcranial Doppler ultrasound in intensive care medicine].

Transcranial Doppler sonography (TCD) enables measurement of blood flow velocities in the basal intracerebral vessels. The most important applications of TCD in the ICU are the diagnosis and monitoring of vasospasms caused by subarachnoid hemorrhage after rupture of an aneurysm. Further indications are the non invasive diagnosis of critical decreases of cerebral perfusion pressure, the evaluation of brain death and the monitoring of thrombolysis of occlusions of the middle cerebral artery. TCD lends itself as a valuable non invasive bedside-monitoring tool, which enables continuous or intermittent monitoring of intracerebral hemodynamics without strain for the patients. Disadvantages to be mentioned are the dependence of experienced examiners and the long lasting training phase required to achieve the requisite experience.

Blood Flow Velocity↗
PubMed1992

[Intensive care of cerebral hemorrhage].

Critically ill patients with intracerebral hemorrhage require immediate treatment in an intensive care unit. In the acute phase of the disease the patients are endangered from increased intracerebral pressure, respiratory disorders (aspiration!) and hypertension. An adequate intensive care management consisting of sedation, analgesia, intubation and mechanical ventilation, correct body positioning and treatment of hypertension is of decisive importance for the prognosis of these patients. The aim of this report is to discuss the most important therapeutic strategies and arising problems in the course of intracerebral hemorrhage.

Brain Damage, Chronic↗
PubMed1991

[Multiple cerebrovascular lesions as fatal late sequelae of syphilis].

A previously healthy man, aged 33 years, suddenly developed a hemiparesis and right facial paresis, as well as anisocoria and motor aphasia, preceded by recurrent attacks of dizziness. On admission he was somnolent. A flow murmur was heard over both carotid arteries; the blood pressure was 160/80 mm Hg. Cerebral computed tomography demonstrated multiple hypodense areas in the area supplied by several cerebral arteries, and marked cerebral oedema. Angiography of the aortic arch and the supra-aortic branches showed an occlusion of the left common carotid artery and a stenosis of the brachiocephalic trunk. The cerebral oedema, caused by ischaemia, did not respond to treatment. The patient died on the fourth hospital day from brainstem "strangulation". At autopsy syphilitic mesaortitis with characteristic lymphoplasmacellular endangiitis of the vasa vasorum of the aortic arch was demonstrated as the cause of the "aortic arch syndrome". Serology confirmed the diagnosis of an untreated tertiary syphilis. (VDRL titre 1:256; TPHA reactive; IgM-SPHA titre 1:64). Although a very rare cause, a late stage of syphilis should be considered in the differential diagnosis of cerebrovascular lesions in youngish patients.

Adult↗
PubMed1990

[Steroid therapy in subarachnoid hemorrhage].

Increase in intracranial pressure due to brain oedema is one of the most frequent complications of subarachnoid hemorrhage (SAH), apart from vasospasm and hydrocephalus. Up to now the administration of corticosteroids at various dosages has been the standard therapy for brain oedema. With this retrospective study we tried to answer the question whether the administration of dexamethasone at high dosage in patients with SAH bears an increased risk of medical complications such as infections, gastrointestinal bleeding and diabetes mellitus. 171 consecutive patients of our intensive care unit, 51 men and 120 women (average age 52.4 +/- 13.6 years) were included in the study. 107 patients received dexamethasone in high doses according to Gobiet's scheme. 64 patients who were not given any steroids formed the control group. Almost the same frequency of gastrointestinal bleeding was registered in the steroid group (2.8%) and in the control group (3.1%). No increase in diabetic problems was found in the steroid group, either. The steroid group showed an increase in infections (38.3% compared with 28.1% in the control group; p less than 0.001). The increase, however, was entirely due to the more frequent occurrence of urinary tract infections (14.0% vs. 4.7%). Dexamethasone therapy at high dosage bears no increased risk of medical problems in patients with SAH, except for a greater number of urinary tract infections. However, stomach ulcer prophylaxis and monitoring of blood sugar levels and electrolytes are deemed necessary.

Adolescent↗
PubMed1990

Transcranial Doppler monitoring during percutaneous transluminal aortic valvuloplasty.

Cerebral blood flow was studied in 12 elderly patients with severe calcific aortic stenosis by means of transcranial Doppler sonography (TCD) during percutaneous transluminal aortic valvuloplasty (PTAV). In 8 of these 12 patients duplex sonography revealed a stenosis of the internal carotid artery (ICA) exceeding 50%. Frequency spectra of 10 patients showed a satisfactory quality and were analyzed. In 7 subjects balloon inflation was well tolerated and systolic blood pressure did not drop below 75 mmHg. In these patients, whether they had a stenosis of the ICA or not, blood flow velocity in the middle cerebral artery (MCA) did not decrease to a critical level. The authors defined "critical" as a reduction of mean blood flow velocity in the MCA exceeding 50% or a decrease below 35 cm/sec. Three patients showed a rapid decrease of systolic aortic pressure below 75 mmHg. In these subjects mean blood flow velocity in the MCA dropped to levels below 35 cm/sec. Deflation and retraction of the balloon resulted in a rapid increase of systemic blood pressure and flow velocity in the MCA. This report demonstrates TCD to be a useful monitoring method of determining residual perfusion in patients with aortic stenosis during PTAV.

Aged↗
PubMed1989

The value of the electrocardiogram in the diagnosis of acute rejection after orthotopic heart transplantation.

The value of a change in summated electrocardiographic voltage as a predictor of cardiac rejection is uncertain in patients treated with low-dose triple immunotherapy (cyclosporin, azathioprine, and corticosteroids) following orthotopic cardiac transplantation. Ten recipients were studied daily and the summated QRS voltages from 600 electrocardiograms were calculated. A single observer graded 147 endomyocardial biopsies. During the study period there were 18 episodes of acute rejection with myocyte necrosis. Only three episodes of rejection were heralded by a significant change in QRS voltage, yielding a positive predictive value of 13% for the technique. Three episodes of severe bacterial infection were preceded by significant decreases in QRS voltage. In one patient with a global pericardial effusion, QRS voltage was related to the depth of effusion measured by echocardiography. These data show that QRS voltage is of extremely limited value in the prediction of cardiac rejection in patients treated with low-dose triple immunotherapy.

Adult↗
PubMed1988

Effects of naftidrofuryl in patients with intermittent claudication.

In a randomized, double-blind, placebo-controlled study in patients with peripheral arterial occlusive disease stage IIb of Fontaine's classification, the efficacy of naftidrofuryl, a vasoactive substance, was investigated. Forty patients--31 men and 9 women with an average age of 62.98 +/- 10.65 years--were admitted to the study. All had a history of claudication for at least six months. The duration of the trial was eighteen weeks. After a washout period of two weeks the patients received either two times 400 mg naftidrofuryl or two identical placebo tablets daily for eight weeks. Subsequently a crossover from verum to placebo and vice versa was carried out and the alternative medication was administered for another eight weeks. Clinical results were evaluated by measuring painfree and maximal walking distance by treadmill test at a speed of 3.2 km/h and an inclination of 12 degrees. Systolic ankle pressure and brachial pressure were measured by Doppler ultrasound, and ankle/arm pressure ratio was calculated. Treadmill test, Doppler ultrasound examination, and laboratory data analysis were performed at the beginning of every study period, every four weeks during and at the end of the study. Results. The patients in both groups showed an initial homogeneity of age, risk factors, concomitant diseases, walking distance, and Doppler indices. After eight weeks naftidrofuryl resulted in a statistically significant increase in painfree (p less than 0.02) and maximal walking distance (p less than 0.05). The placebo-treated group showed only a slight, statistically nonsignificant increase in both painfree and maximal walking distance.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗