Biomedical subjects
Publications and source records attributed to M Hennerici.
Ten days after accidental exposure to carbon monoxide, a 17-year-old youth developed transitory choreoathetosis of both arms, face, and neck, with moderate dysarthria. CT revealed symmetric bilateral infarction in the head of the caudate nucleus, the putamen, and the small parts of the anterolateral globus pallidus.
Explore the source record for details and available documents.
The natural history of a group of 76 patients without neurological symptoms, but with untreated extracranial arterial disease demonstrated by angiography 10 years ago, was studied. During this period 46 patients died, and coronary artery disease was the most common cause of death (n = 25). Six patients suffered a lethal stroke, five patients had a stroke before they died from other causes and five of the six surviving patients, who became symptomatic developed TIAs, followed by a stroke in two cases, leaving only one who suffered a sudden stroke without premonitory warning symptoms. Although the overall cumulative stroke rate (18 per cent) was three times higher than normal, the cerebrovascular territories affected corresponded only twice with the original extracranial carotid lesion. Therefore, early carotid endarterectomy is inadvisable for the majority of asymptomatic patients and repetitive non-invasive prospective study of these patients is favoured for selection of more appropriate timing for individual treatment.
The natural history of a prospectively selected group of neurologically asymptomatic patients with extracranial arterial disease (EAD) was studied. 35 of 184 patients died over a period of follow-up of four years (mean = 21 months). Only four of them had a stroke, while coronary artery disease was the far more common cause of death (n = 19). Among those patients still alive 12 reported transient ischaemic attacks, two a stroke, and 116 remained asymptomatic--only two patients could not be followed. Thus by life-table analysis, the cumulative stroke rate was only 6%, irrespective of death or survival, about the same as the average risk of death in a normal population (5%). However, the probability of EAD progression was 88% as revealed by subsequent continuous-wave Doppler analysis of both the carotid and vertebral arteries in the neck. Neither the degree of initial EAD nor its progression during follow-up were found to represent significant indicators of the patient's cerebrovascular risk. Since the majority of symptomatic patients did not proceed to frank strokes but presented with TIAs, prophylactic surgical treatment may reasonably be delayed.
A high-resolution ultrasound B-mode imaging system combined with a 16-sequential range-gated pulsed Doppler flow measuring device was used for the evaluation of nonstenotic extracranial carotid artery disease. Various types of atherosclerotic lesions were differentiated by Duplex system examinations in 54 carotid arteries examined in vitro in a postmortem study and in 51 carotid arteries examined in vivo from patients with angiographically proven cerebrovascular disease. In addition, the multigated Doppler system allowed the analysis of flow velocity profiles throughout the carotid arteries, the distinction between intraarterial flow and recent thrombus, and in particular the estimation of local flow alterations, which are diagnostic in the presence of sonolucent and shadowed plaques behind echo-dense lesions. A number of difficulties, which at present limit the application of Duplex system examination as a non-invasive "stand alone" method for detecting carotid disease, are discussed.
Non-invasive examination of 431 vessels in 333 patients with cerebrovascular disease in all stages was performed in order to compare the reliability of the periorbital Doppler test alone and together with the more difficult insonation of the carotid arteries in the neck (combined Doppler). These findings were compared with those of subsequent arteriography. Extracranial obstructive (greater than 50%) carotid disease was detected with 100% sensitivity by the combined Doppler, but with only 48% sensitivity by the periorbital indirect test. The specific ability of both methods to identify non-stenotic carotid arteries (less than 50%) was similar at about 98%. Only the combined Doppler examination reliably differentiated various degrees of obstruction, comparable to that obtained with arteriography. Non-obstructive plaques could not be detected or excluded by either Doppler test. More refined methods will be necessary for their evaluation.
Eleven patients with occlusion of one internal carotid artery showed marked reduction of regional cerebral blood flow (rCBF) through the hemisphere on the affected side with high rCBF on the opposite side. Six of the patients had no surgery, during follow-up of 2 to 5 years. rCBF increased on both sides leaving a persisting asymmetry of rCBF. Five patients had extracranial-intracranial bypass; rCBF increased on the affected side but not on the opposite side. Asymmetry of rCBF between the hemispheres remained but was much less than in the non-operated group.
From 1977 to 1984, 752 reconstructions of the supra-aortic arteries were performed at our service. In a group of 31 patients presenting with transient ischemic attacks (13) or minor strokes (15), preoperative multiplane angiograms identified lesions from various causes in extremely high locations (fibromuscular dysplasia, 10; atherosclerosis, 6; traumatic changes, 10; spontaneous dissection, 3; and mycotic aneurysms and others, 4) in 34 internal carotid arteries (aneurysms, 10; and stenosis, 24). Surgery was performed on 30 patients. Flow restoration was achieved by resection and vein graft replacement (20), gradual dilatation (5), thromboendarterectomy (6), and tangential clip for exclusion of a lateral aneurysm (1). Only one patient was treated with an extracranial-intracranial anastomosis because the stenosis extended into the carotid siphon. One patient was treated with heparin. Exposure of the internal carotid artery (ICA) at the base of the skull required dissection of the digastric muscle, careful mobilization of the cranial nerves, and detachment of the styloid process in 29 patients. Partial resection of the mastoid process was helpful in two patients. The carotid bone canal was opened from the lateral side in four cases to allow the most distal anastomosis 1 cm within the carotid canal. Back-bleeding was controlled by a balloon catheter. A shunt was impossible to use and clamping time averaged 62 +/- 40 minutes. Except for one recurrent stroke and two transient ischemic attacks no other neurologic deficits occurred. Cranial nerve damage could not be avoided in 21 cases (nervus recurrens, 7; nervus glossopharyngeus, 16; and nervus facialis, 4) but disappeared clinically within a 1- to 6-month period in all but two. Each surgical patient underwent control angiography, which demonstrated 30 arteries to be patent, two became occluded, and one had an insignificant stenosis. We conclude that standard surgical techniques are unsuitable for repair of highly located lesions of the ICA. Although extracranial-intracranial anastomosis has been proposed in patients with planned ligation of the ICA, the anatomic reconstruction remains advantageous because flow is restored to normal and the source of emboli is eliminated. With the use of a special approach, graft replacement can be performed up to the base of the skull.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
The natural history of a prospectively selected group of neurologically symptomless patients with extracranial arterial disease (EAD) was studied. 23 of 122 patients died over a period of follow-up of from eleven to thirty-six months (mean = seventeen), but only 3 from stroke and 10 from cardiac failure. Among those patients still alive 8 reported transient ischaemic attacks, 1 a stroke, and 90 remain symptomless. Thus, by life-table analysis, the cumulative stroke rate was only 7%, irrespective of death or survival, the same as the average risk of death in a normal population. However, by subsequent continuous-wave Doppler examination of carotid and vertebral arteries, the probability of EAD progression was 85%. Involvement of initially unaffected arteries occurred either alone (25) or in combination with a deterioration of the original stenosis (14)--the latter alone was seen in 9 patients. A combined carotid and vertebral lesion was found to be the only significant indicator of cerebrovascular risk, which was six times greater than that for unilateral or bilateral carotid lesions.
In 47 patients under 45 years of age (average age 35.4 years) with more or less localised cerebral ischaemia without evidence of arteriosclerosis echocardiography showed mitral valve prolapse in 13 cases. This was slightly more frequent than in an age and sex-matched control group. The difference was not statistically significant. In three quarters of the patients (n = 35) a significantly raised beta-thromboglobulin level was found indicating increased platelet activity. No definite conclusions can be drawn as to the cause of cerebral ischaemia which is probably due to embolism. However, treatment with platelet aggregation inhibitors should be considered.
Explore the source record for details and available documents.
Direct comparison with neuroradiologic and surgical data show that stenoses and occlusions of the innominate trunk may be recognized safely by Doppler ultrasound despite localisation close to the aorta. Formation of sonographically demonstrable and haemodynamically complicated vascular by-passes is the reason for the mainly asymptomatic or very uncharacteristic complaints of these cases (78%) among the relatively rare stenosing occlusions of the lumen (0,65%) of the innominate trunk (18 out of 2768 patients). Only in four cases were there focal neurological losses or symptoms of hypoperfusion of the arm. Invasive diagnostic measures should thus be used sparingly. The indication for vascular surgery should be limited to a few cases as long as the natural course of these extracranial vascular changes and the risk of cerebral injury have not been established with certainty.
In unilateral stenosis of the internal carotid artery tonography shows the differences in amplitudes in a comparison of the two sides; in bilateral stenosis it shows markedly reduced amplitudes with an intermittent absence of the pulse amplitudes. When extrasystoles occur there are characteristic reductions in the amplitudes. As a result, this method of examination can be very important in the differential diagnosis of amaurosis fugax. Thanks to its simplicity and the fact that an ECG can be made simultaneously the method has a wide range of clinical applications.
The prevalence of hemodynamically significant disease of the extracranial cerebral arteries was studied in 188 consecutive patients with angiographically proven coronary artery disease (CAD) by means of the Doppler ultrasound method. 24 (= 12.8%) patients had a significantly reduced perfusion of the common or internal carotid artery, proximal subclavian artery with subclavian steal, or vertebral artery. 2 patients showed a simultaneous involvement of two neck arteries, 3 patients of three neck arteries. The incidence of significant flow impairment of the neck arteries rose with increasing coronary artery involvement: 5.4% in 1-vessel CAD, 12.3% in 2-vessel CAD, 16.3% in 3-vessel CAD. Due to a considerable number of false negative and false positive findings, auscultation proved to be unreliable in the detection of hemodynamically relevant flow disturbances of the extracranial cerebral arteries. It is suggested that at least all candidates for aortocoronary bypass surgery should undergo ultrasound Doppler sonography of the neck arteries.
Eleven patients with subclavian steal syndrome underwent end-to-side transposition of the subclavian into the common carotid artery. The post-operative evaluation was done in every case by neurological examination, brachial blood pressure measurement, transcutaneous Doppler examination and by angiography. The operative result of this reconstruction, which was performed mainly on high-risk patients, was excellent. The symptoms of subclavian steal disappeared. In all but one patient the brachial pressure raised to normal. After transposition a blood flow reduction of 20% was measured intraoperatively in the peripheral common carotid artery, while the vertebral blood flow reversed to its natural direction. The peripheral common carotid artery pressure measured simultaneously remained unchanged, and hemodynamic criteria of carotis steal were not detected. The blood flow quality at the anastomosis was measured by the turbulence index in patients with an ideal reconstruction. The amount of blood flow distortion caused by the anastomosis was negligible. Therefore a long patency is expected. In patients with occlusive disease of the proximal subclavian artery we like to recommend the transposition as the procedure of choice, because the method uses one single incision for the extrathoracic exposure and one anastomosis-only without any graft material.
The results of a study in which visual evoked responses (VERs) and a modified Pulfrich method were compared showed that both methods are very effective for the diagnosis of multiple sclerosis. With VERs, 97% of the multiple sclerosis cases were diagnosed correctly, while the corresponding value for the Pulfrich method was 93%. In contrast to VERs, the Pulfrich method allows only measurement of latency differences between the two visual pathways. This method involves measuring the speed required to cause a shift in the apparent depth location of a large, moving, striped pattern observed with a neutral density filter over one eye. A pathological transmission time was inferred when the patients observed a shift in the depth of the moving pattern either without any filter at all or with a filter whose attentuation was no more than 0.2 log units. A further criterion for pathology was a difference of more than 10% between the two eyes in the retinal speed required for a depth displacement using a 1.5 log unit filter. This test requires about 15 minutes, and can be carried out by a technical assistant.