Ultrasound assessment of brain supplying arteries (extracranial)

Ultrasonography of the brain-supplying arteries is a non-invasive and highly efficient technique for the assessment of a stenosis or a vessel occlusion in patients with cerebrovascular diseases. This article reviews the examination technique for a standardized ultrasound assessment of the extracranial carotid and vertebral arteries. It further describes the multiparametric grading criteria of internal carotid artery stenosis and it gives recommendations for a standardised documentation of findings. Additionally, it proposes recommendations for intima-media thickness measurement and for classifying atherosclerotic plaques with B-mode ultrasonography. Moreover, criteria for the diagnosis of in-stent stenoses, vertebral artery dissections and subclavian steal syndrome are provided.

Ultrasound assessment of brain supplying arteries (transcranial)

Ultrasonography of intracranial arteries is a non-invasive and highly efficient method for the diagnosis and follow-up of patients with cerebrovascular diseases, also in the bedside setting of the critically ill. For reliable assessment and interpretation of sonographic findings, the technique requires - apart from dedicated anatomic and pathophysiological knowledge of cerebral arteries and their hemodynamics - the comprehension of alternative imaging modalities such as CT or MR angiography. This article reviews the transcranial color-coded duplex sonographic (TCCS) examination technique including the transcranial Doppler sonography (TCD) for a standardized ultrasound assessment of the intracranial arteries and typical pathological cases. As a complementary tool, transorbital ultrasound for the assessment of the optic nerve sheath diameter and adjacent structures is also described in this article.

Poststenotic Distal Caliber Reduction Predicts Very High-Grade Proximal Internal Carotid Artery Stenosis

BACKGROUND

Angiography relates the residual lumen to the poststenotic distal lumen (NASCET criterion) and expresses the result in percent lumen reduction. This method is not applicable when there is a collapse of the distal lumen, as seen in severe stenosis. The purpose of this study was to evaluate whether the reduced poststenotic caliber could be an additional sonographic criterion for estimation of the degree of stenosis.

METHODS

We measured the caliber of the distal lumen of the extracranial internal carotid artery (ICA) in 57 patients with low-grade stenosis <50% (NASCET criterion), and in 57 patients with unilateral stenosis of ≥ 50 %. All were classified following international recommendations. The criteria used included the poststenotic velocity to discriminate moderate to high-grade stenosis (50-70%) from very high-grade (≥ 80 %) stenosis. In addition, we measured the interrater reliability of the ultrasonic measurement of the lumen in the distal ICA.

RESULTS

In the group of patients with 50% to 70% stenosis, the distal lumen was 4.3 ± 0.6 mm. In the group with very high-grade stenosis ≥ 80%, the distal lumen was 2.6±0.5mm (p<0.0001). A distal lumen of 3.2 mm or less predicted a very high-grade stenosis with a sensitivity of 0.92 and a specificity of 0.96 (AUC 0.986; 95% CI 0.97-1.00; p=0.0001).

CONCLUSION

The distal poststenotic lumen is an additional ultrasonic criterion to discriminate a very high-grade ICA stenosis from a lesser degree of ICA stenosis. It can help avoid misinterpretation due to the high variability of intrastenotic peak systolic velocities (PSV) in very high-grade ICA stenoses.

Microembolizations in the Arterial Cerebral Circulation in Patients with Atrial Fibrillation Ablation Using the Cryoballoon Technique-Protocol and Methodology of a Prospective Observational Study

There is considerable uncertainty regarding the impact of microembolic signals (MESs) on neuropsychological abilities in patients receiving pulmonary vein isolation and beyond using the cryoballoon technique. We conducted the largest prospective observational study on this topic, providing insights into the gradual unmasking of procedure-related MESs and their impacts on neuropsychological outcomes. MESs were continuously detected periprocedurally using transcranial Doppler ultrasonography. Neuropsychological status was evaluated comprehensively using the CERAD Plus test battery, which consists of 11 neuropsychological subtests. Patients with atrial fibrillation were included in the study with an equal distribution (50:50) of paroxysmal or persistent presentations. Of 167 consecutive eligible patients, 100 were included within the study enrollment period from February 2021 to August 2022. The study, including the documentation of all follow-up visits, ended in November 2022. This paper focuses on describing the study protocol and methodology and presenting the baseline data.

Analysis of the effect of cortisone on the QT interval

BACKGROUND

Cardiac death caused by malignant arrhythmias is very prevalent. Prolongation of the QT interval is a relevant aspect in arrhythmia mechanisms. Prior studies have revealed that the QTc interval could be shortened by cortisone. Moreover, in an animal model of long QT syndrome, cortisone treatment shortens the ventricular action potential duration. The present study investigated the effect of methylprednisolone (MPS) on the QTc interval in cardiovascularly healthy humans.

METHODS

Patients who had just been diagnosed with multiple sclerosis receiving MPS therapy were analysed prospectively. Demographic data, laboratory values, anti-arrhythmic medication and baseline and follow-up ECGs were extracted from the patients' medical records.

RESULTS

Seventy-eight patients were included. The mean ± standard deviation age was 47 ± 15 years. The values of the electrolytes were normal. All patients were treated with MPS for 3 or 5 days. The heart rate increased at the beginning of MPS therapy and decreased during the subsequent period. ECG measurements showed that the QTc interval was prolonged at the beginning of MPS therapy and shortened over the course of treatment. The longest QTc intervals were obtained by calculation with Bazett's formula.

CONCLUSIONS

In humans, cortisone shortens the QTc interval over time. The analysis indicates a cumulative effect of cortisone that lasts longer. The results of our pilot study reveal that cortisone might be added to therapeutic strategies in patients with long QT syndromes. Further clinical studies have to be carried out to analyze potential clinical options.

Update: Muskel- und Nervensonografie

Die Sonografie von Nerven und Muskeln hat sich zu einem essenziellen Baustein der Diagnostik von Erkrankungen des peripheren Nervensystems und der Muskulatur entwickelt. Häufig gelingt eine umfassende Aufklärung einer Läsion erst durch die Kombination aus Kenntnissen über eine elektrophysiologisch nachgewiesene gestörte Funktion des Nervs und über sonografisch festgestellte morphologische Veränderungen des Nervs und des angrenzenden Gewebes.

POS0015 PREVALENCE OF NEUROPATHIES IN RHEUMATIC AND MUSCULOSKELETAL DISEASES

Background:

In rheumatic and musculoskeletal diseases (RMDs), peripheral neurons can be affected, which can result in sensory symptoms like pain, burning, tingling, numbness and motor symptoms like muscle-atrophy or even paresis. More detailed knowledge about the prevalence and the cause of neuropathy (NP) in RMD are urgently needed, especially as RMD patients may develop different subtypes of NP.

Objectives:

The aim of this project was to assess the prevalence and the individual types of NP in rheumatoid arthritis (RA), spondyloarthritis (SpA) and systemic sclerosis (SSc) patients, and to elucidate the clinical, neurophysiological and neuropathologic features of associated NP.

Methods:

Baseline questionnaires and neurological and physical examination were used to elucidate the presence of neuropathic pain and autonomic dysfunction. Laboratory tests were performed to exclude other causes for NP. Electrophysiological tests were performed to differentiate demyelinating from axonal large fiber (LF)NPs. Additionally, skin biopsies were used to detect an involvement of small fibres (SF).

Results:

A total of 31 patients (median age 64 years (range 43-75)) were included. The majority of patients were female (90%). The mean disease duration was 10 years (1-41 years). More than 50% of the patients were diagnosed with RA, 7 with SpA and 6 with SSc. Of 31 patients, 48% (15/31) had clinical signs of NP and of those, neurophysiological examination showed 14 axonal 2, demyelinating and 4 mixed types. A combined LFNP and SFNP was present in 35% (11/31) of the patients. In 4 patients, only a SFNP was detectable, and in only two patients, no NP was detectable.

Conclusion:

NP was detectable in 94% (29/31) of the RMD patients, with LFNP predominating. This high proportion of NP in RMD suggests a surprisingly high coincidence of both diseases.

Table 1.

Subtypes of NP in RMD

Number of patientsAxonal NP14/31 (45%)Demyelinating NP2/31 (6%)Mixed axonal and demyelinating NP4/31 (12%)Sensory NP9/31 (26%)Sensorimotor NP5/31 (10%)Motor NP1/31 (3%)

Disclosure of Interests:

None declared.

Sonografie peripherer Nerven: Tumore und Ganglien peripherer Nerven

Die Sonografie wird häufig als Methode der ersten Wahl zur Untersuchung von tastbaren Raumforderungen der Extremitäten angewendet. Tumore peripherer Nerven können unterteilt werden in periphere Nervenscheidentumore wie Schwannome und Neurofibrome, die von spezifischem neuralen Gewebe ausgehen, und in solche, die von unspezifischem Gewebe des Nervs ausgehen. Zur zweiten Gruppe gehören nervale Fibrolipome, intraneurale Perineuriome, Hämangiome und auch intraneurale Ganglien. Der folgende Artikel hat zum Ziel, eine Übersicht über die typischen sonografischen Befunde sowie über den Zusatznutzen der Sonografie gegenüber der elektrophysiologischen Untersuchung von Tumoren und Ganglien von peripheren Nerven zu geben.

Sphenopalatine Ganglion Stimulation to Augment Cerebral Blood Flow

Background and Purpose—

Many patients with acute ischemic stroke are not eligible for thrombolysis or mechanical reperfusion therapies due to contraindications, inaccessible vascular occlusions, late presentation, or large infarct core. Sphenopalatine ganglion (SPG) stimulation to enhance collateral flow and stabilize the blood-brain barrier offers an alternative, potentially more widely deliverable, therapy.

Methods—

In a randomized, sham-controlled, double-masked trial at 41 centers in 7 countries, patients with anterior circulation ischemic stroke not treated with reperfusion therapies within 24 hours of onset were randomly allocated to active SPG stimulation or sham control. The primary efficacy outcome was improvement beyond expectations on the modified Rankin Scale of global disability at 90 days (sliding dichotomy), assessed in the modified intention-to-treat population. The initial planned sample size was 660 patients, but the trial was stopped early when technical improvements in device placement occurred, so that analysis of accumulated experience could be conducted to inform a successor trial.

Results—

Among 303 enrolled patients, 253 received at least one active SPG or sham stimulation, constituting the modified intention-to-treat population (153 SPG stimulation and 100 sham control). Age was median 73 years (interquartile range, 64–79), 52.6% were female, deficit severity on the National Institutes of Health Stroke Scale was median 11 (interquartile range, 9–15), and time from last known well median 18.6 hours (interquartile range, 14.5–22.5). For the primary outcome, improved 3-month disability beyond expectations, rates in the SPG versus sham treatment groups were 49.7% versus 40.0%; odds ratio, 1.48 (95% CI, 0.89–2.47); P =0.13. A significant treatment interaction with stroke location (cortical versus noncortical) was noted, P =0.04. In the 87 patients with confirmed cortical involvement, rates of improvement beyond expectations were 50.0% versus 27.0%; odds ratio, 2.70 (95% CI, 1.08–6.73); P =0.03. Similar response patterns were observed for all prespecified secondary efficacy outcomes. No differences in mortality or serious adverse event safety end points were observed.

Conclusions—

SPG stimulation within 24 hours of onset is safe in acute ischemic stroke. SPG stimulation was not shown to statistically significantly improve 3-month disability above expectations, though favorable outcomes were nominally higher with SPG stimulation. Beneficial effects may distinctively be conferred in patients with confirmed cortical involvement. The results of this study need to be confirmed in a larger pivotal study.

Clinical Trial Registration—

URL: https://www.clinicaltrials.gov . Unique identifier: NCT03767192.

Sonographie peripherer Nerven: Nervenkompressionssyndrome

Zu den häufigsten Anwendungen der Sonografie peripherer Nerven gehört die Untersuchung von Nervenkompressionssyndromen. Der folgende Artikel hat zum Ziel, eine Übersicht über die typischen sonografischen Befunde sowie über den Zusatznutzen der Sonografie gegenüber der elektrophysiologischen Untersuchung bei den häufigsten Nervenkompressionssyndromen wie dem Karpaltunnelsyndrom, der Ulnarisneuropathie am Ellenbogen, dem Loge de Guyon-Syndrom, dem Interosseus posterior-Syndrom, der Meralgia parästhetica, der Peronaeusneuropathie am Fibulaköpfchen und dem hinteren Tarsaltunnelsyndrom zu geben.

One decade of oral anticoagulation in stroke patients: Results from a large country-wide hospital-based registry

Background New evidence regarding stroke prevention in atrial fibrillation has been published. Implementing knowledge into clinical practice remains challenging. Aims To investigate oral anticoagulants in stroke patients documented in a nationwide registry. Methods The database is an obligatory federal-state-wide hospital-based registry that covers more than 95% of all ischemic strokes, transient ischemic attacks and intracerebral hemorrhages in a community of more than six million inhabitants (Hesse/Germany). We analyzed oral anticoagulants prescribed on discharge in patients with stroke or transient ischemic attack during 2006-2015. Results From 2006 to 2015, we annually selected median 20,895 patients. From 2006 to 2015, the proportion of patients treated with oral anticoagulants increased (9.8% to 24%). The annual proportion of patients with atrial fibrillation remained constant (median: 23%). In atrial fibrillation patients treated with oral anticoagulants, the age increased (median 2008/2009: 76.9 years vs. 2014/2015 79.4 years). The percentage of treated individuals in atrial fibrillation increased dramatically (2006: 30.1% to 2015: 74.5%); in 2015, 30.8% of these patients received vitamin K antagonists and 70.2% new oral anticoagulants. Independent factors associated with new oral anticoagulants therapy were a previous medication with new oral anticoagulants and a treatment on stroke unit. Between new oral anticoagulants- and vitamin K antagonists-treated patients (2015), no differences in age were noted (both mean: 79.4 years). Conclusions The new oral anticoagulants availability enhanced a general trend treating more target patients with oral anticoagulants.

Factors associated with shunt dynamic in patients with cryptogenic stroke and patent foramen ovale: an observational cohort study

BACKGROUND

As previously reported there is evidence for a reduction in right to left shunt (RLS) in stroke patients with patent foramen ovale (PFO). This occurs predominantly in patients with cryptogenic stroke (CS). We therefore analysed factors associated with a shunt reduction on follow-up in stroke patients suffering of CS.

METHODS

On index event PFO and RLS were proven by transesophageal echocardiography and contrast-enhanced transcranial Doppler-sonography (ce-TCD). Silent PE was proved by ventilation perfusion scintigraphy (V/Q) within the stroke work-up on index event; all scans were re-evaluated in a blinded manner by two experts. The RLS was re-assessed on follow-up by ce-TCD. A reduction in shunt volume was defined as a difference of ≥20 microembolic signals (MES) or the lack of evidence of RLS on follow-up. For subsequent analyses patients with CS were considered; parameters such as deep vein thrombosis (DVT) and silent pulmonary embolism (PE) were analysed.

RESULTS

In 39 PFO patients suffering of a CS the RLS was re-assessed on follow-up. In all patients (n = 39) with CS a V/Q was performed; the median age was 40 years, 24 (61.5%) patients were female. In 27 patients a reduction in RLS was evident. Silent PE was evident in 18/39 patients (46.2%). Factors such as atrial septum aneurysm, DVT or even silent PE were not associated with RLS dynamics. A greater time delay from index event to follow-up assessment was associated with a decrease in shunt volume (median 12 vs. 6 months, p = 0.013).

CONCLUSIONS

In patients with CS a reduction in RLS is not associated with the presence of a venous embolic event such as DVT or silent PE. A greater time delay between the initial and the follow-up investigation increases the likelihood for the detection of a reduction in RLS.

Cerebral vein thrombosis: clinical manifestation and diagnosis

Background

Cerebral venous thrombosis (CVT) is a disease with a wide spectrum of symptoms and severity. In this study we analysed the predictive value of clinical signs and symptoms and the contribution of D-dimer measurements for diagnosis.

Methods

We evaluated consecutive patients admitted with suspected CVT receiving non-invasive imaging. Symptoms and symptom combination as well as D-dimer levels were evaluated regarding their diagnostic value.

Results

239 patients were included in this study, 170 (71%) were females. In 39 patients (16%) a CVT was found. For identifying a CVT patients underwent either a venous CT-angiography or MR-angiography or both. No combination of symptoms either alone or together with the D-dimer measurements had a sensitivity and positive predictive value as well as negative predictive value and specificity high enough to serve as red flag. D-dimer testing produced rates of 9% false positive and of 24% false negative results. For D-dimer values a Receiver Operating Characteristic curve (ROC) and the area under the curve (AUC = 0.921; CI: 0.864 - 0.977) were calculated. An increase of sensitivity above 0.9 results in a relevant decrease in specificity; a sensitivity of 0.9 matches a specificity value of 0.9. This corresponds to a D-dimer cut-off level of 0.16 μg/ml.

Conclusion

Imaging as performed by venous CT-angiography or MR-angiography has a 1 to 2 in 10 chance to detect CVT when typical symptoms are present. D-dimer measurements are of limited clinical value because of false positive and negative results.

High frequency of silent pulmonary embolism in patients with cryptogenic stroke and patent foramen ovale

BACKGROUND AND PURPOSE

Deep vein thrombosis and pulmonary embolism (PE) prove venous embolic activity and enforce the suspicion of paradoxical embolism in patients with stroke with patent foramen ovale. Because it has implications in secondary prevention, we investigated the frequency of silent PE in such a cohort of patients.

METHODS

Patients with cryptogenic stroke or transient ischemic attack and patent foramen ovale who underwent a ventilation perfusion scintigraphy were identified from a stroke registry. Blinded from clinical data, ventilation perfusion scintigraphy scans were re-evaluated independently by 2 experts. Patients showing at least a subsegmental defect were considered as having silent PE. Factors potentially associated with PE were analyzed.

RESULTS

The evaluation included 151 patients. Median age was 55.2 years and 59.9% were male. In 56 (37%) patients, silent PE was found; a deep vein thrombosis was evident in 11 (7%) patients. Atrial septal aneurysm was identified in 39 patients and hypermobile atrial septum in 37 patients. Atrial septal aneurysm and hypermobile atrial septum were independently associated with PE. In females, intake of oral contraceptives showed certain association with PE (6 of 25 versus 3 of 40; P=0.07).

CONCLUSIONS

Silent PE frequently occurs in patients with cryptogenic stroke and patent foramen ovale, particularly when atrial septal aneurysm or hypermobile atrial septum are present.

Embolic Lesion Pattern in Stroke Patients With Patent Foramen Ovale Compared With Patients Lacking an Embolic Source

BACKGROUND AND PURPOSE

Multiple acute ischemic lesions on diffusion-weighted magnetic resonance imaging (DWI-MRI) are thought to be of embolic origin. However, in several patients with multiple ischemic lesions on DWI-MRI, no embolic source was detected, despite a thorough clinical work-up. Stroke etiology in such cases is then classified as cryptogenic. In other patients, a potential embolic source is limited to a patent foramen ovale (PFO) that may act as an embolic source of unsure relevance. We therefore examined the prevalence of the multiple-lesion pattern in patients with cryptogenic stroke compared with patients with PFO.

METHODS

We screened 650 stroke patients by DWI-MRI. For the subsequent evaluation, we excluded patients with a cardiac embolic source other than PFO, symptomatic carotid artery disease, and other apparent stroke causes, such as dissection or vasculitis, and patients whose diagnostic work-up was incomplete. For the remaining 106 patients, we found DWI lesions in 73, who were subjected to further evaluation.

RESULTS

There were no differences in the occurrence of the multiple-lesion pattern in patients with cryptogenic stroke compared with patients with PFO, either for the entire group or for the subgroup of young stroke patients who were <50 years old. Patients with PFO showed a significantly higher incidence of multiple lesions in the posterior circulation.

CONCLUSIONS

The multiple-lesion pattern on DWI-MRI is not uncommon, even when extensive testing does not reveal any embolic source. Therefore, it is not possible to discriminate between cryptogenic stroke and stroke from an assumed paradoxical embolism.

Sonographic harmonic grey scale imaging of brain perfusion: scope of a new method demonstrated in selected cases

AIM

Transient response harmonic transcranial sonography is a new bed-side technique which provides information on brain tissue perfusion. This paper demonstrates the scope of perfusion transcranial sonography (p-TCS).

METHODS

P-TCS was performed in an axial insonation plane through the thalamus and third ventricle in a case with Moyamoya disease and a patient with bilateral thalamic oedema due to thrombosis of the internal cerebral veins, and compared to results in 10 healthy controls. Signal increase induced by a bolus of an echo-contrast agent (Optison trade mark ) was quantified in regions of interest (ROI) in the thalamus (TH), lentiform nucleus (LN) and the cerebral white matter (WM).

RESULTS

In Moyamoya disease p-TCS could demonstrate a decreased perfusion in the WM and LN as a result of bilateral, high-grade stenoses of the intracranial part of the internal carotid artery. Peak intensity was increased in the TH due to collateral cross-over flow from the vertebrobasilar system. TH perfusion was decreased in thrombosis of the internal cerebral vein thrombosis with normal LN perfusion. The extention of the thalamic oedema into the white matter could also be demonstrated by decreased perfusion in the adjacent WM. ROI ratios of different tissues proved helpful in quantifying the perfusion results.

CONCLUSION

P-TCS is a new, promising technique that can supply information on pathological brain tissue perfusion at the patient's bed-side.

[Heart and brain]

The heart and the brain are closely related, not only proverbially but also anatomically and pathogenetically. Cerebral circulation begins in the heart, through which a major pathomechanism of stroke is predestined: 20-30% of all cerebral infarctions are cardioembolically related. Both organs are equally affected by atherosclerotic processes. Despite this close relationship, generalizing extrapolations from heart to cerebral infarction are usually not applicable. The occurrence of coronary infarction is almost exclusively due to atherosclerosis with plaque rupture, whereas embolic mechanisms such as in cerebral infarction or microangiopathic processes play almost no role. On the other hand, the brain also influences the cardiovascular system. Thus, infarctions particularly in the region of the right insular cortex can induce cardiac arrhythmia and ECG and blood pressure changes. Additionally, vegetative crises with increased sympathicotonia and increased parasympathicotonia are common clinical observations in severe brain disease. A close relation between the two organs can also be observed in preventive pharmacotherapy. Similar principles, however, stand in contrast to considerations of various clinical risks and values, as can be seen for example in anticoagulation or thrombolysis. In this study, special attention is paid to cardioembolic stroke and preventive medicine aspects of coronary and cerebral vascular disorders. In particular, stress is placed on the discerning of commonalities and various evaluations of test results.

[Stroke treatment with stroke unit and rehabilitation by a team. A model for a staged management]

This is a report of an interdisciplinary approach to diagnosis and treatment of stroke, combining a stroke unit and rehabilitation in one clinic. This series contains unselected patients from a narrow surrounding. Mean age of 559 patients was 68.7 years (median 70 years). 25% of patients had an initial Barthel index of < 30, 20% presented with TIA's and PRIND's. 9% suffered from cerebral hemorrhage. The unbroken chain of care allowed a relative short length of stay in the acute care (9.4 days) without prolonging the rehabilitation phase. The one month mortality was 6.7%, one year mortality 18.3%. Discharge to a nursing home was necessary in 5.4%. Overall more than 90% of our patients have been treated continuously in our clinic. Combining modern diagnostics with early onset rehabilitation seem advantageous.

Persistent GAD 65 antibodies in longstanding IDDM are not associated with residual beta-cell function, neuropathy or HLA-DR status

Persistent humoral autoimmunity to the enzyme glutamic acid decarboxylase (GAD) has been described in a substantial proportion of patients with insulin-dependent diabetes mellitus (IDDM) of long duration. The source of the stimulus for this autoimmune reactivity is still unknown. Because the GAD 65 isoform is mainly expressed in pancreatic beta-cells and in the nervous system we investigated in the present study of the largest number of well characterized patients with longstanding IDDM (n = 105; median duration: 21 years; range: 10-46 years) the presence of autoantibodies to GAD 65 and their relationship to a residual C-peptide response or peripheral and autonomic neuropathy. Additionally we studied the HLA-DR status relative to GAD 65 antibodies in 86 out of the 105 individuals. One hundred healthy control subjects and 100 recent onset IDDM patients were also studied for GAD 65 antibodies. GAD 65 antibodies were detected in a radioligand-binding-assay with recombinant human GAD 65 and were present in 32% of the long-term diabetic patients, 82% of the recent onset IDDM patients and in 3% of the healthy control subjects. A preserved C-peptide response to i.v. glucagon (Hendriksen criteria) was observed in 23% of the long-term IDDM patients. Autonomic neuropathy and peripheral neuropathy was identified using criteria based on both symptoms and formal testing giving a frequency of 67% vs 79%. The HLA specific DR 4/X was observed in 47% and HLA-DR 3/X in 22% of the long-term IDDM patients. Patients who were heterozygous for DR3/DR4 were found in 23% of the cases. GAD 65 antibodies were significantly less frequent in the long-term IDDM patients compared to recent onset IDDM (p < 0.001), and diabetes duration showed a significant negative correlation with GAD 65 antibody index levels (r = 0.22, p < 0.01). Interestingly, GAD 65 antibodies were not significantly correlated either with residual beta-cell function or neuropathy and no particular HLA-DR status was associated with persistent GAD 65 antibodies. In conclusion neither residual beta-cell function nor diabetic neuropathy or a certain HLA-DR specificity are exclusively associated with persistent autoimmunity directed to GAD 65 in longstanding IDDM. The stimulus for the persistent humoral immune response and its significance for the disease process and its complications remain to be established.