Michael Hennerici

SPONTANEOUS PROGRESSION AND REGRESSION OF SMALL CAROTID ATHEROMA

A specially designed high-resolution (10 MHz) ultrasound duplex-system was used to study prospectively the appearance of 43 extracranial non-stenotic carotid plaques (less than 30% lumen narrowing) in 31 patients over 18 months. 13 presented with ipsilateral and 9 with contralateral cerebrovascular events; 9 were asymptomatic. Most carotid atheromas remained unchanged (51%) or progressed (30%), but spontaneous regression was seen in 19% at regular 3 monthly re-examination. Regression was restricted to volume reduction of soft plaques and healing of ulcerative lesions; fibrous and hard plaques remained unchanged or progressed. Intraplaque haemorrhage was only observed in 3 instances and was always associated with later progressive encroachment. Comparison of bilateral plaques in the same individual suggested a uniform advance with duration of the atherosclerotic process. None of the patients had cerebrovascular events during follow-up.

Progress in carotid artery surgery at the base of the skull

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.

STROKE RISK FROM SYMPTOMLESS EXTRACRANIAL ARTERIAL DISEASE

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.

The role of subclavian-carotid transposition in surgery for supra-aortic occlusive disease

From 1977 through 1985, 1043 patients underwent operation for supra-aortic occlusive disease. One hundred thirty-four of these patients (13%) with 146 lesions of the aortic arch branches (innominate, 25; subclavian, 103; and multiple, 10) had one or more symptoms of subclavian steal (78%), transient ischemic attacks (37%), arm ischemia (37%), and others (7%). However, according to results of a critical prospective neurologic examination, the classic steal syndrome appeared in only 13 patients (10%), vertebrobasilar insufficiency in 32 patients (24%), and hemispheric symptoms in 48 patients (36%). Symptomatic and/or significant internal carotid occlusive disease was present, ipsilateral in 28% and contralateral in 31% of the patients. Other supra-aortic vessels were involved in 49% of the patients. During the same period 192 patients with supra-aortic occlusive disease were treated without surgical intervention for various reasons. Fifty-five patients (27%) were completely asymptomatic except for the presence of reversed flow within the vertebral artery. The surgical approach in 138 operations was extrathoracic (ET) in 71% of patients (innominate artery, 2; subclavian artery, 95; and arch syndrome, 1) and transthoracic (TT) in 29% of patients (innominate artery, 23; subclavian artery, 8; and arch syndrome, 9). Generally, bypass procedures were preferred, but for 72 (71%) of the subclavian lesions subclavian-carotid transposition (SCT) was performed. Three patients had been referred for complications of previous carotid-subclavian bypass. The grafts were removed and vertebral and arm circulation restored by SCT. Carotid end-arterectomy was performed simultaneously (20%) or staged (3%) in 8% of the innominate procedures and 25% of the subclavian reconstructive procedures.(ABSTRACT TRUNCATED AT 250 WORDS)

Chemically modified low density lipoproteins as inducers of enzyme release from macrophages

Macrophages carry receptors on their surface for acetylated low density lipoprotein (ac‐LDL). Receptor‐mediated endocytosis of ac‐LDL is followed by intracellular cholesterol accumulation. We investigated whether occupation of these binding sites evokes the release of hydrolytic enzymes from mouse peritoneal macrophages cultured for up to 48 h. ac‐LDL at concentrations ranging from 25–250 was noted to promote in a dose‐dependent fashion secretion of the neutral proteinase elastase (EC 3.4.21.37) and the lysosomal acid hydrolases N‐acetyl‐β‐glucosaminidase (EC 3.2.1.30), β‐glucuronidase (EC 3.2.1.31), β‐galactosidase (EC 3.2.1.23), α‐mannosidase (EC 3.2.1.24) and cathepsin D (EC 3.4.23.5). This stimulatory effect was non‐cytotoxic. LDL modified by treatment with malondialdehyde was also capable of augmenting enzyme liberation into culture supernates. These findings may have implications for some aspects of the atherosclerotic process.

Doppler colour flow imaging after carotid endarterectomy

Sixty-six patients (72 carotid arteries) were examined after carotid endarterectomy (CEA) using Doppler colour flow imaging (DCFI). Examinations were performed 4-18 days (mean: 7 days) after surgery (32 patients, 34 arteries) or between 2 and 100 months (mean: 39 months) after CEA (34 patients, 38 arteries). Minor vessel wall abnormalities were found in 36% in the internal carotid artery (ICA) and in 55% in the common carotid artery (CCA) or bifurcation. One patient had a minor residual ICA stenosis after surgery; two low-grade stenoses and three ICA-occlusions were diagnosed at follow-up. Altered flow patterns occurred most in CCA (90%) and were predominantly located adjacent to the vessel wall and in dilated vascular segments of the CCA. Disturbed haemodynamics in the ICA were less marked (57%) and frequently found in the central vessel lumen or diffusely distributed. We conclude that surgically induced changes of the vessel geometry and residual or recurrent vascular wall abnormalities are often associated with distinct haemodynamic disturbances, which can reliably be detected by DCFI.

137. Fortschritte in der Behandlung extrakranieller Carotisläsionen an der Schädelbasis

SummaryIn 25 patients presenting with transient attack (9), stroke with good recovery (15) or local symptoms (5), preoperative arteriography identified lesions of the internal carotid artery (ICA), which were located extremely high, bilaterally in four and unilaterally in 21 patients (aneurysm 9, stenosis 20). Treatment varied according to etiology (vein graft 19, dilatation 4, thromboendarterectomy 4, tangential clip 1, extraintracranial bypass 1). Exposure of the skull base was required in 19 cases and in 2 the most distal anastomosis was performed within the bone canal (ischemia time 62 min). In contrast to the literature, the high patency rate (28/29), the low neurological deficit rate (1/29) and sufficient retrogression of cranial nerve damage (21/29) all demonstrated that anatomical reconstruction should be the preferred method, because the flow is restored to normal and the danger of embolism eliminated.Zusammenfassung25 Patienten mit transitorischen Attacken (9), Insult (15) und lokalen Symptomen (5) wiesen in 4 Fällen bilateral und in 21 Fällen unilateral eine Stenose (20) oder ein Aneurysma (9) der Arteria carotis interna (ACI) an der Schädelbasis auf. Je nach Ätiologie kamen verschiedene Methoden zur Anwendung (Veneninterponat 19, Dilatation 4, Desobliteration 4, tangentialer Clip 1, extraintrakranieller Bypass 1). Die ACI wurde in 19 Fällen bis an die Schädelbasis freigelegt, in 2 Fällen erfolgte mit spezieller Technik die Transplantatanastomose im Carotiskanal (Ischämiezeit 62 min). Die hohe Durchgängigkeitsrate (28/29), das geringe neurologische Defizit (1/29) und die bisherige Rückbildung der Halsnervenausfälle (21/29) zeigen entgegen den Angaben in der Literatur, daß auch in diesem Carotisabschnitt der Rekonstruktion der Vorrang vor allen anderen indirekten Maßnahmen einzuräumen ist.

153. Die hämodynamisch signifikante Stenose der A. carotis interna

SummaryThe results of indirect and direct Doppler examination and pressure gradient determination were compared with the bilateral angiography in 50 patients with internal carotid artery stenosis. Group 1 (stenosis below 80 % square area reduction) : the accuracy of Doppler vs angiography was 63 %, pressure gradient vs angiography 84%, Doppler vs pressure gradient 77%, mean gradient 12 mmHg. Group 2 (more than 80% square area reduction), Doppler vs angiography 82 %, pressure gradient vs angiography 72 %, Doppler vs pressure gradient 64 %. Mean pressure gradient 25 mm Hg. In conclusion, every lumen reduction of more than 80 % is critical and surgical therapy is urgent, since sudden local occlusion occurred in 4 of 15 patients.ZusammenfassungZur Bestimmung des Stenosegrades wurden Dopplersonographie und intraoperative Druckmessung mit der Standard-II-Ebenen Angiographie verglichen. Gruppe 1 (Stenose kleiner als 80 %): Doppler/Angio 63% (positive Korrelation); Druckgradient/Angio 84%; Doppler/Druckgradient 77%; mittlerer Gradient 12 mm Hg. Gruppe 2 (Stenose groβer als 80 %) : Doppler/Angio 82 %; Gradient/Angio 72 %, Doppler/Gradient 64 %, mittlerer Gradient 25 mm Hg. Die funktionelle Signifikanz der Stenose nahm bei geringerem Kollateralfluß zu, kenntlich an der dopplersonographischen ≫Überschätzung≪ und an einem relativ großen Gradienten. Aus klinischer Sicht sind Einengungen größer als 80 % ≫kritisch≪ und erfordern sofortige chirurgische Therapie, da in 4 von 15 Patienten lokale Verschlüsse auftraten, welche gerade noch rechtzeitig operabel waren.