[New options in the therapeutic management of acute ischaemic stroke. Good results with combined i. v. and i. a. lysis and mechanical thrombectomy]. / Neue Wege bei der Akuttherapie des ischämischen Schlaganfalls. Behandlungserfolge mit kombinierter i. v. und i. a. Lyse sowie mechanischer Thrombektomie.

BACKGROUND: Standard therapy for acute ischaemic stroke is the intravenous thrombolysis with rtPA. A combined therapy with intravenous bridging and consecutive intraarterial thrombolysis and mechanical thrombectomy is a relatively new option in patients with proximal vessel occlusion. PATIENTS AND METHODS: 10 Patients with a CTA proven proximal vessel occlusion in the anterior circulation (ACI, carotis bifurcation, MCA) in CTA were treated with a combined therapy with i. v. and i. a. thrombolysis and thrombectomy with a Solitaire FR stent device. RESULTS: All Patients were recanalized, the NIHSS changed from 15.6 to 3.3. 8 out of 10 patients had nearly no symptoms when dismissed. There were no direct therapeutic complications. CONCLUSION: Combined therapy with i. v. and i. a. thrombolysis and thombectomy with the Solitaire FR stent device is a promising option in patients with acute proximal vessel occlusion in the anterior circulation.

Phase shift and correlation coefficient measurement of cerebral autoregulation during deep breathing in traumatic brain injury (TBI).

BACKGROUND: Impairment of cerebral autoregulation is known to adversely affect outcome following traumatic brain injury (TBI). The phase shift (PS) method of cerebral autoregulation (CA) assessment describes the time lag between fluctuations in arterial blood pressure (ABP) and cerebral blood flow velocity (CBFV) in the middle cerebral artery. An alternative method (Mx-ABP) is based on the statistical correlation between ABP and CBFV waveforms over time. We compared these two indices in a cohort of severely head injured patients undergoing controlled, 6-breaths-per-minute ventilation. METHODS: PS and Mx-ABP were calculated from 33 recordings of CBFV and MAP in 22 patients with TBI. Spearman's correlation coefficient was used to assess the agreement between PS and Mx-ABP. The relationship between ICP slow wave amplitude, MAP slow wave amplitude and mean ICP was also examined. FINDINGS: Mean values for Mx-ABP and PS were 0.44 +/- 0.27, and 49 +/- 26 (degrees), respectively. PS correlated significantly with Mx-ABP (r = -0.648, p < 0.001). A Bland-Altman plot of normalised Mx-ABP and Phase Shift values showed no significant bias or relationship (mean difference = 0.0004, r = -0.037, p = 0.852). During the test procedure, ICP fluctuated in an approximately sinusoidal fashion, with a mean amplitude of 4.96 +/- 2.72 mmHg (peak to peak). The magnitude of ICP fluctuation during deep breathing correlated weakly but significantly with mean ICP (r = 0.391, p < 0.05) and with the amplitude of ABP fluctuations (r = 0.625, p < 0.0005). CONCLUSIONS: Phase shift and Mx-ABP in TBI are well correlated. Deep breathing presents as an effective tool with which to assess autoregulation using the phase shift method.

Dynamic autoregulation testing in the posterior cerebral artery.

BACKGROUND AND PURPOSE: Dynamic autoregulation has been studied predominantly in the middle cerebral artery (MCA). Because certain clinical conditions, ie, presyncopal symptoms or hypertensive encephalopathy, suggest a higher vulnerability of autoregulation within posterior parts of the brain, we investigated whether the cerebral blood flow velocity (CBFV) is modulated differently within the posterior cerebral artery (PCA). METHODS: Spontaneous oscillations of CBFV and arterial blood pressure (ABP) in the frequency range of 0.5 to 20 cycles per minute were studied in 30 volunteers (supine and tilted positions). Analysis was based on the "high-pass filter model," which predicts a specific frequency-dependent phase and amplitude relationship between oscillations in CBFV to ABP. These parameters, characterized as phase shift angles and transfer function gains, were calculated from simultaneously recorded beat-to-beat blood pressure and transcranial Doppler signals of the PCA and MCA by means of cross-spectrum analysis. RESULTS: In the MCA and PCA, phase shift angles were decreased, and gains were elevated with increasing oscillation frequency. The PCA gain values in supine and tilted positions were significantly higher than in the MCA. CONCLUSIONS: The phase and amplitude relationship between CBFV and ABP showed a frequency dependence in the PCA similar to that in the MCA. The study therefore suggests that the high-pass filter model of dynamic cerebral autoregulation can be applied to the PCA. In this model the generally higher gain values in the PCA indicate a lower damping of ABP oscillations, which are transmitted to the posterior part of cerebral circulation.

Dynamic autoregulation testing in patients with middle cerebral artery stenosis.

BACKGROUND AND PURPOSE: Cross-spectral analysis (CSA) of spontaneous oscillations in cerebral blood flow velocity (CBFV) and arterial blood pressure is considered a sensitive and convenient method for dynamic autoregulation testing. So far, it has been unclear whether CSA can be used to assess stenoses of the intracranial arteries. METHODS: This study for the first time applies CSA to 26 patients with low-, moderate-, and high-degree M1 stenoses and 14 normal control subjects. Using CSA, we studied spontaneous oscillations (M waves, 3 to 9 cpm; B waves, 0.5 to 3 cpm) in continuous recordings of transcranial Doppler of the middle cerebral artery and simultaneously recorded beat-to-beat blood pressure. RESULTS: A gradual decrease in pulsatility indexes confirmed the increasing hemodynamic relevance of the stenoses. Compared with control subjects, M-wave phase shifts between CBFV and blood pressure were gradually reduced with increasing degree of M1 stenosis (control subjects, 44.6+/-21.1 degrees; high-degree stenosis, 16.7+/-19.5 degrees ). The phase relation between B waves in blood pressure and CBFV was shifted to positive values (low-degree stenosis, -9.7+/-108.4 degrees; high-degree stenosis, 50.9+/-43.8 degrees ). CONCLUSIONS: Because B- and M-wave phase shifts seem to characterize the degree of autonomy of CBFV modulation, this study suggests that with increasing degree of M1 stenosis, the arteriolar function is impaired. It shows that CSA is of indicative use for the assessment of intracranial artery stenosis.

Subclinical autonomic disturbances in multiple sclerosis.

We compared results from non-invasive autonomic testing [sympathetic skin responses (SSR), heart beat variation during deep breathing, and orthostatic manoeuvre with transcranial Doppler monitoring in 22 patients] with motor and somatosensory evoked potentials (MEP and SEP) in 30 unselected patients with multiple sclerosis. We found a similarly high yield of pathological results for SSR, MEP and SEP (66.7%, 65.5%, and 69%, respectively). When analysed for each limb (n = 120), SSR were highly correlated with MEP and SEP (for both P < 0.001). Heart beat variation was reduced in only 3 patients. In 4 of 22 patients orthostatic manoeuvre induced a pathological decrease in cerebral blood flow velocity despite normal systemic blood pressure being maintained. We conclude that SSR may be a useful additional diagnostic tool in patients with multiple sclerosis. Cerebral dysautoregulation is a rather frequent finding, although its significance is not known.

Spontaneous oscillations in cerebral blood flow velocity in normal humans and in patients with carotid artery disease.

Spontaneous oscillations in cerebral blood flow velocity (CBFV) in normals and in patients with stenoses or occlusions of the internal cerebral artery were measured using transcranial Doppler sonography. In normal subjects, large oscillations of up to +/- 30% from the mean CBFV were found with low frequencies between 0.4 and 9 cycles/min. No correlations between CBFV oscillations and systemic circulatory parameters were detected. In patients with carotid artery obstructions the CBFV oscillations were significantly reduced in the middle cerebral artery ipsilaterally to a hemodynamically significant lesion, but not contralaterally. Our results support the hypothesis that spontaneous oscillations (B-waves) of small pial vessels are responsible for the CBFV fluctuations.

Orthostatic changes of cerebral blood flow velocity in patients with autonomic dysfunction.

Simultaneous registrations of intracranial blood flow velocity parameters achieved by transcranial Doppler sonography and basic cardiovascular parameters were carried out during orthostatic changes in normal controls, diabetic patients and patients with pandysautonomia. Normal subjects had a rapid increase in heart rate at a constant blood pressure and a slight decrease in cerebral blood flow velocities associated with a mild increase of the pulsatility index (PI) after being tilted from a horizontal to a vertical position. Diabetics showed a fixed heart rate reflecting the disturbed autonomic innervation but only minor changes of cerebral blood flow velocity, which is similar to normal cerebrovascular autonomic regulation. Patients with pandysautonomia had a fixed heart rate associated with a decrease of systemic blood pressure but a failure of compensatory cerebral autoregulation to maintain normal flow velocity values after standing up. The results suggest that in diabetics cerebrovascular autonomic regulation is intact in contrast to cardiac autonomic function, while in patients with pandysautonomia both functions are disturbed. Criteria for the interpretation of autonomic regulatory mechanisms involved in cerebrovascular flow measurements are discussed.

Spontaneous oscillations of arterial blood pressure, cerebral and peripheral blood flow in healthy and comatose subjects.

Slow and rhythmic spontaneous oscillations of cerebral and peripheral blood flow occur within frequencies of 0.5-3 min-1 (0.008-0.05 Hz, B-waves) and 3-9 min-1 (0.05-0.15 Hz, M-waves). The generators and pathways of such oscillations are not fully understood. We compared the coefficient of variance (CoV), which serves as an indicator for the amplitude of oscillations and is calculated as the percent standard deviation of oscillations within a particular frequency band from the mean, to study the impairment of generators or pathways of such oscillations in normal subjects and comatose patients in a controlled fashion. With local ethic committee approval, data were collected from 19 healthy volunteers and nine comatose patients suffering from severe traumatic brain injury (n = 3), severe subarachnoid hemorrhage (n = 3), and intracerebral hemorrhage (n = 3). Cerebral blood flow velocities were measured by transcranial Doppler ultrasound (TCD), peripheral vasomotion by finger tip laser Doppler flowmetry (LDF), and ABP by either non-invasive continuous blood pressure recordings (Finapres method) in control subjects, or by direct radial artery recordings in comatose patients. Each recording session lasted approximately 20-30 min. Data were stored in the TCD device for offline analysis of CoV. For CoV in the cerebral B-wave frequency range there was no difference between coma patients and controls, however there was a highly significant reduction in the amplitude of peripheral B-wave LDF and ABP vasomotion (3.8 +/- 2.1 vs. 28.2 +/- 16.1 for LDF, p < 0.001; and 1.2 +/- 0.7 vs. 4.6 +/- 2.8 for ABP, p < 0.001). This observation was confirmed for spontaneous cerebral and peripheral oscillations in the M-wave frequency range. The CoV reduction in peripheral LDF and ABP oscillations suggest a severe impairment of the proposed sympathetic pathway in comatose patients. The preservation of central TCD oscillations argues in favor of different pathways and/or generators of cerebral and peripheral B- and M-waves.

[Neurological and psychiatric assessment of syncope]. / Neurologische und psychiatrische Abklärung in der Synkopendiagnostik.

A transient loss of consciousness (TLOC) may have different causes. The term syncope is restricted to an underlying sudden decrease in cerebral perfusion. In most cases, syncopes or other causes of TLOC are recognizable by a basic diagnostic evaluation (history taking, physical examination, ECG, and supine and upright blood pressure measurements). Cues for epileptic seizures, e.g., delayed recovery, should prompt an extended search for an epileptic focus. Unusual features of the attacks without any hint for a syncopal or an epileptic origin require the psychiatric inspection of suspected dissociative (psychogenic) seizures. Neurogenic orthostatic hypotension results from sympathetic failure. The underlying disease (Parkinson's disease, pure autonomic failure, autonomic neuropathy, etc.) has to be identified by neurological examinations.

Recovery of the blood pressure - cerebral flow relation after carotid stenting in elderly patients.

BACKGROUND: As a sensitive and convenient means for the cerebral hemodynamic monitoring, dynamic cerebral autoregulation testing could be especially useful in medical conditions where less invasive diagnostics and therapies are preferred. This study analysed the effect of carotid stenting on dynamic autoregulation in elderly patients focussing on the relation between blood pressure and cerebral blood flow velocity. METHODS: We examined 20 patients age 69 +/- 8 years with coexisting cerebrovascular and medical risk factors before and at least six month after stenting of severe carotid stenoses. Data were compared to 24 age-matched healthy controls. Slow spontaneous oscillations were studied in continuous recordings of Transcranial Doppler and beat-to-beat blood pressure. Analysis was based on the "high-pass filter model", which predicts a positive phase relationship between these oscillations. FINDINGS: Whereas phase shift angles were diminished (20.4 +/- 14.1 degrees ) before stenting, after stenting these values were significantly increased to normal (48.1 +/- 16.6 degrees ), to the level of controls (46.7 +/- 15.9 degrees ). Medical conditions such as coronary artery disease, arterial hypertension, and dyslipidemia did not diminish this recovery. The level of increase was inversely correlated with the initial autoregulatory deficit (r = -0.68) which was largest with insufficient collateral blood supply and symptomatic carotid stenoses. CONCLUSIONS: The study showed that an impaired cerebral autoregulation may recover after stent-guided carotid angioplasty even in the elderly with co-existing medical conditions. In this respect to regain vasomotor capability, patients with cerebrovascular risk factors seemed to benefit particularly.

Impact of vertebral artery disease on dynamic cerebral autoregulation.

OBJECTIVES: This study applied dynamic cerebral autoregulation (DCA) testing distally to severe bilateral vertebral artery disease (BVAD). METHODS: Using continuous monitoring of beat-to-beat blood pressure and transcranial Doppler of the posterior cerebral arteries (PCA) were examined in 20 patients with BVAD and 22 controls. DCA testing was based on the 'high-pass filter model', which predicts a positive phase relationship between spontaneous oscillations (M-waves 3-9 cpm and R-waves 9-20 cpm) in blood pressure and cerebral blood flow velocity. RESULTS: In patients with BVAD, DCA testing detected autoregulatory deficits of different degrees. The lowest M-wave phase shift angles were found in the PCA territory distally to intracranial BVAD. CONCLUSION: This study suggests that DCA testing of the PCA could help to quantify the hemodynamic impact of BVAD. It highlights the relevance of functional TCD sonography as a useful diagnostic tool for the hemodynamic evaluation of vertebrobasilar disease.

Measurement of interocular delays with dynamic random-dot stereograms.

A psychophysical method of measuring interocular delay based on dynamic random-dot stereograms is presented. The measurement requires only about 2 min. The sensitivity of this method to detect differences in the transmission times of the two optic nerves is demonstrated in patients with multiple sclerosis and in healthy subjects in whom interocular delays were produced by using different luminance levels for each eye. This new method may be a useful and economic method for monitoring the time course of optic neuritis.

[Quantitative tilt table study with TCD monitoring. A reliable method for the diagnosis of neurocardiogenic syncope (vasovagal syncope)]. / Die quantitative Kipptischuntersuchung mit TCD-Monitoring. Eine reliable Methode zur Diagnose der neurokardiogenen Synkope (vasovagalen Synkope).

The clinical significance of quantitative tilt-table examination with TCD monitoring in the diagnosis of neurocardiogenic syncope is evaluated. A 50-year-old male suffered a neurocardiogenic syncope during tilt-table examination with a strong drop in blood pressure, an increase in cerebrovascular resistance as evidenced by transcranial Doppler monitoring, and a 30-s cardiac asystole, followed by a generalized seizure. No further syncope could be elicited during tilt-table examination after beta-blocker treatment. It was hypothesized that hyperactivity of the left ventricular mechanoreceptors due to increased force of ventricular contraction during a state of reduced venous backstream to the heart was responsible for eliciting the neurocardiogenic syncope. Tilt-table examination with an upright position for at least 45 min enables the diagnosis of a neurocardiogenic syncope to be made with sufficient sensitivity and specificity. Several studies have shown that medication with beta-blockers is successful in the treatment of neurocardiogenic syncope. The implantation of cardiac pacemakers should only be considered if medication is not successful.

[Examination of the visual system with transcranial magnetic stimulation]. / Untersuchung des visuellen Systems mit der transkraniellen Magnetstimulation.

The influence of transcranially applied magnetic stimuli on the function of the afferent (sensory) and efferent (motor) parts of the visual system have been discussed. Excitatory (positive) phenomena are subjective photic sensations (phosphenes) which can be elicited by transcranial magnetic stimulation over occipital parts of the skull. The phosphenes appear on the left or right side of the visual field depending upon the direction of the coil currents, which determines whether the visual cortex of the right or the left hemisphere is activated. The configuration of the phosphene fields hints at an excitation of the primary visual cortex (Brodmann's area 17). However, magnetic brain stimulation also produces inhibitory (negative) phenomena. When strong magnetic field pulses are applied over the primary visual cortex, foveally presented visual stimuli cannot be identified even when no phosphenes are perceived at the same time. Depending on the position of the stimulation coil, this suppression of perception can be restricted to visual stimuli presented on the right, or left of, above or below the fixation point. No generation or disturbance of eye movements by transcranial magnetic stimulation has been reported before, except for a delay of saccades within a reaction time paradigm.

Estimation of baroreflex sensitivity using transfer function analysis: normal values and theoretical considerations.

Human baroreflex sensitivity is traditionally derived from changes in heart rate due to alterations of the baroreceptor input (pharmacologically or physically induced blood pressure changes). Transfer function analysis (TFA) of changes in heart rate (output function) and physiological blood pressure oscillations (input function) at approximately 0.1 Hz (Mayer waves) has already been accepted as a measure of baroreflex sensitivity (BRS). Transfer function analysis provides gain and phase shift values for each frequency band and body position. We performed TFA in 50 normal subjects in the supine and tilted positions, at mid-frequency (0.05-0.15 Hz) and high-frequency (0.15-0.33 Hz) bands, recording heart rate and blood pressure continuously with a Finapres device. Gain values were in accordance with previous studies. Phase shifts lay within a narrow range for all frequency bands and positions. High correlations were found between phase shifts of the same frequency band, but not for those of the same position. This supports the idea that the transfer mechanisms for the two frequency bands may, in part, be different. There was a poor correlation between gain and phase values on the one hand and, on the other hand, further spectral measures and the results of standard autonomic tests. This suggests that TFA may not only be a measure of BRS, but also a complementary tool for evaluation of autonomic function.

Comparison of standard autonomic tests and power spectral analysis in normal adults.

Standard autonomic measures [heart rate response to deep breathing (HR[DB]), systolic blood pressure response to orthostatic load, the 30:15 ratio, and the Valsalva ratio (VR)] and spectral measures of the heart rate (HR) and the arterial blood pressure (ABP) (MF: mid-frequency band at 0.05-0.15 Hz; HF: high-frequency band at 0.15-0.33 Hz) were performed in 50 healthy subjects. The supine HR-HF and the tilt ABP-MF were taken as indicators of parasympathetic and sympathetic outflow, respectively. The transfer function magnitude of HR related to the ABP in the mid-frequency band estimated the baroreflex sensitivity. The HR[DB] and the 30:15 ratio were correlated with the parasympathetic spectral measure, and the VR was, surprisingly, only correlated with the sympathetic spectral measure. Significant baroreflex contribution was only evident for the 30:15 ratio. The spectral HR data were highly correlated with their corresponding spectral data of ABP. These results provide insights into autonomic regulation, but further studies on both basic physiological mechanisms of these methods and their clinical value have to be performed before a broad application can be recommended.

[Differential orthostatic dysregulation disorders diagnosis]. / Differentialdiagnose der orthostatischen Dysregulationen.

Orthostatic circulatory disorders are frequently the cause of orthostatic intolerance, syncope or dangerous falls. A sufficient therapy should be based on a differential diagnosis by means of an active standing test or a tilt-table test. Three typical pathological reactions of blood pressure and heart rate can be differentiated. The hypoadrenergic orthostatic hypotension is characterised by an immediate drop in blood pressure (systolic drop > 20 mmHg below base line within 3 min) with or without compensatory tachycardia. It is caused by peripheral or central sympathetic dysfunction. Tachycardia (> 30 beats per minute above base line within 10 min) without significant blood pressure drop but with a fall of cerebral blood flow indicates a postural tachycardia syndrome. In general, there is no further somatic dysfunction. Increased venous pooling is thought to be the assumed pathomechanism. A reflex mechanism evokes the neurocardiogenic syncope after a certain time of standing: sympathetic inhibition yields a strong blood pressure drop and vagal activation bradycardia. Proved therapies include use of the mineralocorticoide fludrocortison (hypoadrenergic orthostatic hypotension), of the alpha-agonist midodrin (postural tachycardia syndrome) and of beta-blockers (neurocardiogenic syncope).

Cerebral autoregulation testing after aneurysmal subarachnoid hemorrhage: the phase relationship between arterial blood pressure and cerebral blood flow velocity.

OBJECTIVE: Impairment of cerebral autoregulation (CA) appears to be an important cause for secondary ischemia after subarachnoid hemorrhage (SAH). It has been shown that graded CA impairment is predictive of outcome. Little is known about whether such impairment is present, what causes CA impairment, whether it precedes vasospasm, and whether it is predictive of outcome in patients with severe aneurysmal SAH. DESIGN: Prospective, controlled study. SETTING: Neurosurgical intensive care unit. PATIENTS: Twelve patients after aneurysmal subarachnoid hemorrhage, 40 controls. INTERVENTIONS: Recording of cerebral blood flow velocities and continuous measurement of arterial blood pressure at a controlled ventilatory frequency of six per minute to standardize the influence of intrathoracic pressure changes on blood pressure. MEASUREMENTS AND MAIN RESULTS: We calculated the phase shift angles (deltaphidegrees) between slow (0.1 Hz) arterial blood pressure and cerebral blood flow velocity waves measured by transcranial Doppler ultrasound in the middle cerebral artery during a) posthemorrhage days (PHD) 1-6 (early or prevasospasm phase), and b) during PHD 7-13 (late or vasospasm phase) using a 6/min ventilation protocol, and in 40 controls spontaneously ventilating at the same rate. deltaphi <30 degrees indicated lost CA. Mean flow velocities >100 cm/sec were considered vasospasm. We combined early and late measurements to assess the CA relationship with low cerebral perfusion pressure (CPP) and/or vasospasm. We assessed the Glasgow Outcome Scale (GOS) score at discharge (1 = worst, 5 = best). The admission Hunt and Hess score was 3.6 +/- 0.7. GOS scores were n = 3 (GOS 1), n = 2 (GOS 2), n = 5 (GOS 3), n = 1 (GOS 4), and n = 1 (GOS 5). In the early phase, deltaphi was 40.4 +/- 19.8 degrees (left), and 40.4 +/- 19.2 degrees (right). CPP was 69.4 +/- 10.9, intracranial pressure (ICP) was 6.7 +/- 2.8 mm Hg. In the late phase, deltaphi worsened in six patients and none improved: 32.1 +/- 21 degrees (left), and 26.9 +/- 17.2 degrees (right); CPP was 68.1 +/- 12.1, ICP was 7.5 +/- 3.7 mm Hg. CA was significantly impaired in both phases when compared with normal subjects (deltaphi: 65.7 +/- 24.5 degrees; p < .01 for early, p < .001 for late phase). In the early phase, seven of eight patients in whom autoregulation was intact had a GOS >2 at discharge and disturbed CA on at least one side was predictive of either vegetative condition at discharge or death (p < .01). In the late phase, deltaphi was no longer predictive of outcome. Spasm was present in 8 of 17 vessels (47%) in which CA was lost; no spasm was found in 25 of 28 vessels (89%) in which CA was intact (p < .01). A low CPP was present in 6 of 17 vessels (35%) in which CA was lost; a normal CPP was found in 21 of 27 vessels (78%) in which CA was intact (p > .05, NS). However, 14 of 17 vessels (82%) with lost CA showed spasm and/or low CPP while only 8 of 27 cases (30%) with intact CA had either spasm or low CPP (p < .001). CONCLUSIONS: CA can be assessed in a graded fashion in SAH patients. CA impairment precedes vasospasm; ongoing vasospasm worsens CA. CA assessment early after subarachnoid hemorrhage, within PHD 1-6, is predictive of outcome whereas late assessment is not. CA impairment is associated with cerebral vasospasm and low CPP.

Evidence for embolization from a posterior cerebral artery thrombus by transcranial Doppler monitoring.

BACKGROUND: Transcranial Doppler monitoring enables the detection of emboli passing through intracranial arteries. Comparison of the different intracranial vessels with respect to emboli detection can be of use in identifying the source of embolism. CASE DESCRIPTION: We report the case of a patient with an acute posterior cerebral artery (PCA) infarct on the right side, with evidence for high-degree ipsilateral PCA narrowing on admission. During transcranial Doppler monitoring 3 days later, we found frequent emboli-like signals in the power spectrum of the right PCA distal to the stenosis but not in any other intracranial vessels. Four days later, angiography and transcranial Doppler failed to show PCA narrowing, and transcranial Doppler monitoring of the right PCA showed no further emboli-like signals. A stenosis of the right vertebral artery was regarded as the possible source of thromboembolic narrowing of the PCA. CONCLUSIONS: We assume that in our patient a thrombotic clot in the PCA was resolved autolytically through detachment of small emboli into the distal part of the PCA. We speculate that in the early course of autolysis a larger fragment of the clot had occluded one of the distal branches, thus leading to the small PCA territory infarct.