Lesion patterns in patients with cryptogenic stroke with and without right-to-left-shunt

Background and purpose:  Despite numerous studies, the role of patent foramen ovale (PFO) as a risk factor for stroke due to paradoxical embolism is still controversial. On the assumption that specific lesion patterns, in particular multiple acute ischaemic lesions on diffusion-weighted magnetic resonance imaging, indicate a cardioembolic origin, we compared the MRI findings in stroke patients with right-to-left shunt (RLS) and those without.
Methods:  The records of 486 patients with diagnosis of cerebral ischaemia were reviewed. For detection of RLS, contrast-enhanced transcranial Doppler (c-TCD) was carried out in all patients. An MRI scan of the brain was performed in all patients. Affected vascular territories were divided into anterior cerebral artery, middle cerebral artery, vertebrobasilar artery system including posterior cerebral artery, brain stem and cerebellar stroke, and strokes occurring in more than one territory.
Results:  We did not find a specific difference in neuroradiological lesion patterns in patients with RLS compared with patients without RLS. In particular, 23 of 165 patients (13.9%) with RLS showed multiple ischaemic lesions on MRI in comparison with 45 of 321 patients (14.0%) without RLS ( P  = 0.98). These findings also applied for the subgroup of cryptogenic strokes with and without RLS.
Conclusion:  We found no association between an ischaemic lesion pattern that is considered as being typical for stroke due to cardiac embolism and the existence of PFO. Therefore, our findings do not provide any support for the common theory of paradoxical embolism as a major cause of stroke in PFO carriers.     

Clinical implication of cerebral artery calcification on brain CT

BACKGROUND AND PURPOSE: Arterial calcification is a process of atherosclerosis, usually taking place within advanced atheromatous plaque. In the coronary arteries, calcification seen on computed tomography (CT) often indicates severe stenosis, and is noted in almost all patients with coronary symptoms. Calcification of the cerebral arteries is also frequently observed on brain CT, but its clinical significance has yet to be clarified. To evaluate the clinical significance of cerebral arterial calcification on brain CT, we investigated the angiographic and transcranial Doppler ultrasonography (TCD) findings of calcified cerebral arteries. METHODS: The subjects were 57 patients with ischemic stroke, all of whom underwent brain CT, digital subtraction cerebral angiography and TCD. Stroke subtypes were defined according to TOAST classification. Two clinicians who were blinded in respect to the patients' clinical history and to each other's interpretation, determined the presence of cerebral arterial calcification and the degree of angiographic stenosis. RESULTS: Cerebral artery calcification was noted in 23 patients (40%) out of a total of 46 arteries, consisting of 23 internal carotid, 15 vertebral, 5 basilar, 2 middle cerebral and 1 anterior cerebral artery. The patients with calcification were significantly older and more hypertensive than those without calcification. All the patients with calcification showed either large artery atherosclerosis or lacunar stroke. Hemodynamic alterations measured by TCD were rarely observed in calcified arteries. The severity and extent of the atherosclerotic changes were significantly greater in the patients with calcification than those without calcification. CONCLUSION: These results suggest that cerebral arterial calcification does not directly indicate hemodynamically significant atherosclerotic stenosis involving calcified segments, but indicates the underlying etiology of either large artery atherosclerosis or lacunar stroke, and raises the possibility of a diffuse atherosclerotic process being present in the cerebral circulation.     

Ultrasound, atherosclerosis and stroke at a young age: a cross-sectional long-term follow-up in western Norway

Background and purpose:  Previous studies have shown significantly higher mortality and vascular morbidity amongst patients with ischaemic stroke onset at a young age compared with controls after a mean observation time of more than 11 years.
Methods:  In the present cross-sectional study, we measured the carotid intima-media thickness (IMT) in 140 (75%) of 187 survivors of ischaemic stroke after a mean observation time of 11.9 years. Their mean age when included was 41.1 years. IMT was measured by B-mode ultrasonography.
Results:  Total maximum IMT <1.0 mm was found in 34 (24%) patients, [1.0–1.2 mm) in 29 (21%) patients, [1.2–1.5 mm) in 29 (21%) patients and ≥1.5 mm in 48 (34%) patients. Increasing total maximum IMT was related to increasing age, male gender, recurrent ischaemic stroke, coronary atherosclerosis, peripheral atherosclerosis, smoking, hypertension and diabetes mellitus.
Discussion:  IMT changes confirm increased vascular morbidity in patients who suffered ischaemic stroke at a young age.     

Inflammatory markers, rather than conventional risk factors, are different between carotid and MCA atherosclerosis

BACKGROUND: The apparent differences in risk factors for intra- and extracranial atherosclerosis are unclear and the mechanisms that underlie strokes in patients with intracranial atherosclerosis are not well known. We investigated the conventional vascular risk factors as well as other factors in stroke patients with large artery atherosclerosis. METHODS: Using diffusion weighted imaging (DWI) and vascular and cardiologic studies, we selected patients with acute non-cardioembolic cerebral infarcts within the middle cerebral artery (MCA) territory. Patients were divided into two groups: those with atherosclerotic lesions on the carotid sinus (n = 112) and those with isolated lesions on the proximal MCA (n = 160). Clinical features, risk factors, and DWI patterns were compared between groups. RESULTS: There were no differences in conventional risk factors, but markers for inflammation were significantly higher in patients with carotid atherosclerosis than in those with isolated MCA atherosclerosis (p < 0.01 for both). After adjustments for age/sex and the severity of stroke, an inverse correlation was observed between C-reactive protein levels and MCA atherosclerosis (odds ratio 0.57 per 1 mg/dl increase; 95% confidence interval 0.35 to 0.92; p = 0.02). Internal borderzone infarcts suggestive of haemodynamic causes were the most frequent DWI pattern in patients with MCA occlusion, whereas territorial infarcts suggesting plaque ruptures were most common in those with carotid occlusion. CONCLUSIONS: Our results indicate that inflammatory markers, rather than conventional risk factors, reveal clinical and radiological differences between patients with carotid and MCA atherosclerosis. Plaques associated with MCA atherosclerosis may be more stable than those associated with carotid atherosclerosis.     

Advanced atherosclerosis of the aortic arch is uncommon in ischemic stroke: an autopsy study

Aortic and carotid atherosclerosis are known risk factors for stroke. The aim of the study was to determine the frequency of atherosclerotic lesions in the aorta and carotid arteries in subjects dying of ischemic and hemorrhagic stroke and to determine whether aortic atherosclerosis was associated with any specific ischemic stroke subtype. Autopsies were performed in 207 patients who died during hospitalization for stroke from 1993 to 1997. Subjects ranged in age from 37 to 98 years, mean 74.45 years (SD +/- 11.84). There were 132 women and 75 men. Stroke was hemorrhagic in 66 and ischemic in 141. Advanced atherosclerotic lesions were less frequent in the aortic arch (1.9%) than in the thoracic aorta (51.7%), abdominal aorta (60.4%), or carotid arteries (23.7%). Moderate atherosclerotic lesions in the aortic arch were observed more frequently in ischemic (75.2%) than hemorrhagic stroke (56.1%, p=0.026). Advanced or moderate atherosclerotic lesions in any part of the aorta did not predict ischemic stroke subtype. Advanced atherosclerosis of the carotids was more common in ischemic stroke (28.4%) than hemorrhagic stroke (13.6%, p < 0.05). Advanced atherosclerosis of the carotids was more common in stroke due to atherothrombosis (51.4%) than in stroke due to cardiac embolism (22.1%) or stroke of unknown etiology (5.6%). The low frequency of advanced atherosclerotic lesions of the aortic arch suggests that this disease process is not a common mechanism of stroke.     

经颅多普勒超声和颈动脉超声检测无脑缺血症状的2型糖尿病患者颅内外动脉粥样硬化病变

目的 分析无脑缺血症状的2型糖尿病患者颅内动脉粥样硬化性狭窄和颅外颈动脉粥样硬化病变的发生频率及分布特征,并探讨其危险因素.方法 对94例无脑缺血症状的2型糖尿病住院患者用经颅多普勒超声(TCD)和颈动脉超声判断颅内外动脉粥样硬化病变,颅内动脉只分析狭窄,颅外动脉病变包括颈动脉斑块及狭窄.分析各危险因素的影响.结果 55例(58.5%)有颅内外动脉粥样硬化病变.22例(23.4%)发现有颅内动脉狭窄,明显高于颅外颈动脉狭窄或闭塞(3/94,3.2%,χ~2=16.66,P＜0.01).大脑中动脉是颅内最常受累的动脉(狭窄率17.0%),占狭窄动脉数的58.5%.48例(51.0%)有颅外颈动脉粥样斑块或狭窄.Logistic多元回归分析显示糖尿病病程和合并高血压是颅内外动脉粥样硬化病变的独立危险因素.结论 无脑缺血症状的2型糖尿病住院患者,半数以上有颅内外动脉粥样硬化改变,且与糖尿病病程及合并高血压有关,提示对上述高危患者应常规进行超声检测.     

Combined extracranial and intracranial atherosclerosis in Korean patients

OBJECTIVES: To evaluate the frequency of intracranial atherosclerosis among patients with steno-occlusive extracranial carotid artery disease and to determine if there are factors related to the combined intracranial atherosclerosis. DESIGN: Cross-sectional study. SETTING: A tertiary referral hospital.Patients We studied 142 consecutive patients who had atherosclerotic steno-occlusive lesions (defined as > or =30% narrowing of the luminal diameter or occlusion) of an extracranial carotid artery confirmed by conventional angiography. We excluded patients who had potential cardiogenic sources of embolism. Potential vascular risk factors for each patient were obtained from medical records.Main Outcome Measure We determined the location and severity of atherosclerotic lesions by conventional angiography. We compared the vascular risk factors between patients with steno-occlusive extracranial carotid artery disease alone and patients with combined intracranial atherosclerosis and extracranial carotid artery disease. RESULTS: Intracranial steno-occlusive lesions (> or =30% stenosis or occlusion) were found in 80 patients (56.3%). Of 121 patients with significant (> or =50% stenosis or occlusion) extracranial carotid artery disease, 58 (47.9%) also had significant lesions of intracranial arteries. Univariate and multivariate analyses showed that diabetes mellitus was the only significant factor associated with combined intracranial atherosclerosis in patients with extracranial carotid artery disease. CONCLUSIONS: Intracranial atherosclerosis is common in Korean patients with steno-occlusive extracranial carotid artery disease. Diabetes mellitus is associated with intracranial atherosclerosis in patients who had steno-occlusive extracranial carotid artery disease.     

High prevalence of unrecognized cerebral infarcts in first-ever stroke patients with cardioembolic sources

Background:  With magnetic resonance imaging (MRI) analysis, we investigated the prevalence, clinical significance, and factors related to the presence of unrecognized cerebral infarcts in patients with first-ever ischaemic stroke.
Methods:  We consecutively included patients who were admitted with first-ever stroke. Unrecognized cerebral infarct was defined as an ischaemic infarction or primary intracerebral hemorrhage on MRI irrelevant to the index stroke, without acute lesions on diffusion-weighted image.
Results:  Of the total 203 patients, 78 (39.4%) patients were observed as having unrecognized cerebral infarct. Patients with high-risk cardioembolic sources (e.g., atrial fibrillation) more frequently had unrecognized stroke than those without ( P  = 0.008, 21/36 [58.3%] vs. 57/167 [34.1%]). On univariate analysis, male sex ( P  = 0.027) and cardioembolic source ( P  = 0.008) were associated with the presence of unrecognized cerebral infarcts. After adjustment for gender, age and risk factors, the presence of cardioembolic sources independently increased the risk of unrecognized cerebral infarct ( P  = 0.002, odds ratio 3.56, 95% confidence interval 1.58–8.02). Regarding clinical outcome at 3 months, the presence of unrecognized cerebral infarct was not associated with the poor clinical outcome.
Conclusion:  In our study, the presence of cardioembolic sources was an independent risk factor for the unrecognized cerebral infarct in patients with first-ever stroke.     

Evolving atherosclerosis at carotid and intracranial arteries in Japanese patients with ischemic heart disease: a 5-year longitudinal study with MR angiography

Progression of atherosclerosis at extracranial carotid and intracranial arteries in patients with ischemic heart disease (IHD) is not well defined. We carried out a 5-year longitudinal study with magnetic resonance angiography (MRA) of patients with IHD to assess the incidence of progression of atherosclerosis at extracranial carotid and intracranial arteries and to determine predictors of the progression. We previously performed carotid and intracranial MRA on 67 patients who had received selective coronary angiography for the clinical diagnosis of IHD. Of these 67 subjects, 41 patients gave informed consent to undergo MRA reexaminations to evaluate changes of extra- and intracranial arteries over a 5-year period. The degree of stenosis was divided into five grades depending on the narrowness of the arteries, i.e. normal, mild, moderate, severe and occluded. The average of follow-up period with MRA examination was 58.8 months. The progression of atherosclerosis, as defined as an increase of one grade of the stenosis rating, including both the exacerbation of pre-existing stenosis and the appearance of new stenotic lesions, were found in five patients (12.2%) for the cervical carotid artery and in only one patient (2.4%) for the intracranial artery. A multiple logistic regression analysis revealed that baseline carotid artery stenosis ( P  = 0.008), age ( P  = 0.047), and coronary events during the follow-up period ( P  = 0.048) were significant and independent predictors of progression of carotid atherosclerosis. In conclusion, our findings suggest that follow-up evaluation of the carotid artery is indicated for patients with IHD in whom carotid artery stenosis was detected on an initial examination. Further study is needed with larger numbers of patients to confirm these findings.     

Mechanism of tuberothalamic infarction

Background and purpose: The tuberothalamic artery (TTA), one of the arteries supplying the paramedian thalamic area, is peculiar because it originates from the posterior communicating artery (p‐comA), which connects the vertebrobasilar and carotid systems. Methods: From Stroke Registry, 23 consecutive patients with an acute infarction involving the TTA were selected. We investigated the mechanism of TTA infarction. Results: Fourteen of 23 patients (61%) had coexisting infarctions outside the TTA territory (carotid in three, vertebrobasilar in seven, and both carotid and vertebrobasilar arteries in four patients). Coexisting lesions were most common in the posterior thalamoperforating arterial territory (seven patients). Eleven out of 14 patients (79%) with coexisting lesions had embolic sources from the heart or proximal atherosclerotic arteries, and cardioembolism was the most common mechanism. However, eight of the nine patients with isolated tuberothalamic lesions were classified as small vessel occlusions. More patients with embolic sources had visible p‐comA or fetal‐type posterior cerebral arteries. The vertebrobasilar arterial system played a more dominant role in developing tuberothalamic infarction than the carotid arterial system. Conclusions: Isolated TTA infarctions are rare and mostly because of small vessel occlusion. Patients with coexisting infarctions outside TTA territory usually have an embolic source, predominantly vertebral artery atherosclerosis.     

Effects of atherosclerosis on cerebral vessels: hemodynamic and morphometric studies

In this study hemodynamic and morphometric consequences of atherosclerosis were examined in cynomolgus monkeys. We tested the hypothesis that atherosclerosis augments cerebral vasoconstrictor responses to serotonin. We studied 8 normal and 8 atherosclerotic monkeys, which were fed an atherogenic diet for 17 months. Morphometric studies indicated marked intimal proliferation of extracranial carotid arteries, with only modest reduction in the vascular lumen, as atherosclerotic lesions were displaced outward. Cerebral blood flow was measured with microspheres and microvascular pressure was measured with a micropipette in pial arteries approximately 350 microns diameter. Intracarotid infusion of serotonin reduced microvascular pressure, which indicates constriction of large arteries upstream, but cerebral blood flow did not decrease. Serotonin produced a 2-fold greater reduction in cerebral microvascular pressure in atherosclerotic monkeys than in normal monkeys. Intracarotid histamine increased flow and hypocapnia reduced flow in both normal and atherosclerotic monkeys, without altering cerebral microvascular pressure. We conclude: First, atherosclerosis potentiates constrictor responses to serotonin in large cerebral arteries. Because platelets release serotonin when they aggregate, augmentation of responses by atherosclerosis may have implications for cerebral vascular responses during aggregation of platelets at carotid lesions. Second, despite marked proliferation of intima, atherosclerotic lesions are displaced outward during a prestenotic phase of the disease, so that the lumen is relatively well preserved.     

Cerebral atherosclerosis in Parkinsonian patients

Cerebral atherosclerosis has been previously postulated as a possible etiology for Parkinsonism. Epidemiological studies, however, have suggested a relatively low incidence of ischemic strokes in Parkinsonian patients. The aim of this study was to evaluate the prevalence of extra- and intracranial atherosclerosis in these patients. We performed carotid duplex studies and transcranial Doppler (TCD) examinations in 50 patients with idiopathic Parkinson's disease and in 50 healthy control subjects. The carotid duplex scanning results revealed fewer Parkinsonian patients with stenotic lesions (30% versus 38% in the control group; p=0.4). The TCD results demonstrated lower peak flow velocities in the Parkinsonian group versus the control group, and these differences were statistically significant in the basilar, vertebral and right middle cerebral arteries (p=0.03, 0.001 and 0.04, respectively). The carotid duplex scanning results could not provide a potential explanation for the relatively low occurrence of stroke in Parkinsonian patients, because most strokes are related to carotid atherosclerotic lesions while the TCD results might reflect a diminished blood supply secondary to a decline in tissue metabolism.     

Systemic atherosclerosis in patients with perforating artery territorial infarction

Background: Perforating artery territorial infarction (PAI) is usually a small artery disease (SAD). However, it may also result from branch artery occlusion or arterial embolism from the proximal atherosclerotic lesions. We hypothesized that patients with PAI caused by a SAD may have a distinct pattern of systemic artery involvement from those with PAI caused by large artery diseases. Methods: We investigated retrospectively 329 consecutive patients with PAI who had angiographic studies. Patients were grouped according to the presence or absence of atherosclerosis in the parent artery or relevant artery: no arterial lesion (NAL), relevant artery atherosclerosis (RAA) and parent artery atherosclerosis (PAA). The relevant artery was defined as any artery which can cause index stroke. The parent artery was defined as an original artery that branches out and forms small artery which was responsible for index PAI. Systemic evidence of atherosclerosis and risk factors were compared. Results: Of the 329 patients with PAI, 109 had RAA, 45 had PAA and 175 had neither RAA nor PAA. There were no differences amongst the groups in the classic risk factors for atherosclerosis. Evidence of atherosclerosis in arterial beds other than the relevant artery to the infarction (other cerebral arteries, coronary arteries, descending aorta and peripheral arteries) was significantly lower in the NAL group (49.7%) than in either the PAA group (88.9%) or RAA group (93.6%). Conclusions: Perforating artery territorial infarction with RAA or PAA when compared to PAI without atherosclerosis showed different involvement patterns of systemic atherosclerosis, suggesting potentially different aetiological mechanisms.     

Microemboli on Transcranial Doppler in Patients with Spontaneous Carotid Artery Dissection

High-intensity transient signals on transcranial Doppler sonography (TCD) are associated with atherosclerotic stenosis of the internal carotid artery. Few data exist regarding the detection of high-intensity transient signals in dissected carotid arteries. In the present study, 6 patients with spontaneous carotid dissection, defined by magnetic resonance techniques and duplex sonography, were examined by TCD. Both middle cerebral arteries were monitored simultaneously for 30 minutes. Four of the patients had ipsilateral cerebral ischemia, while 2 presented with other symptoms. High-intensity transient signals were detected in the middle cerebral artery ipsilateral to the dissection in 3 of the 4 patients with cerebral ischemia and in none of the patients with other presenting symptoms. No microemboli were found contralateral to the dissected arteries. Microemboli can be detected distally from dissected carotid arteries. The present findings support the assumption that embolism is a major cause of stroke in patients with carotid dissection, and suggest that high-intensity transient signals are more common among patients with cerebral ischemia secondary to dissection.     

No evidence that severity of stroke in internal carotid occlusion is related to collateral arteries

Background/Aim

The neurological effects of internal carotid artery (ICA) occlusion vary between patients. The authors investigated whether the severity of symptoms in a large group of patients with ipsilateral or/and contralateral ICA occlusion at presentation with ocular or cerebral ischaemic symptoms could be explained by patency of other extra or intracranial arteries to act as collateral pathways.

Methods

The authors prospectively identified all patients (n = 2881) with stroke, cerebral transient ischaemic attack (TIA), retinal artery occlusion (RAO), and amaurosis fugax (AFx) presenting to our hospital over five years, obtained detailed history and examination, and examined the intra and extracranial arteries with carotid and colour‐power transcranial Doppler ultrasound. For this analysis, all those with intracranial haemorrhage on brain imaging and cerebral events without brain imaging were excluded.

Results

Among 2228/2397 patients with brain imaging (1713 ischaemic strokes, 401 cerebral TIAs, 193 AFx, and 90 RAO) who underwent carotid Doppler, 195 (9%) had ICA occlusion. Among those patients with cortical events, disease in potential collateral arteries (contralateral ICA, external carotid, ipsilateral or contralateral vertebral or intracranial arteries) was equally distributed among patients with severe and mild ischaemic presenting symptoms.

Conclusion

The authors found no evidence that the clinical presentation associated with an ICA occlusion was related to patency of other extra or intracranial arteries to act as collateral pathways. Further work is required to investigate what determines the clinical effects of ICA occlusion.     

Subclinical carotid atherosclerosis and cognitive function

Carotid artery atherosclerosis is a major risk factor for stroke and subsequent cognitive impairment. Recent studies indicate that carotid atherosclerosis without clinical stroke may also be an independent risk factor for cognitive decline and dementia. Ultrasonography is an easily assessable and non-invasive method to measure different stages of the carotid artery atherosclerotic process and is widely used in clinical assessment as well as in epidemiological and clinical research. We give a brief review of studies that have investigated degrees of the subclinical atherosclerosis in the carotid arteries in relation to cognitive function and dementia, and we discuss several possible mechanisms that could explain the association between atherosclerosis and cognitive impairment.     

Comparison of the characteristics for in-hospital and out-of-hospital ischaemic strokes

Background and purpose:  Patients who are being admitted to a hospital due to diseases other than stroke may develop a stroke (in-hospital stroke; IHS).
Methods:  We enrolled 111 consecutive patients who developed IHS outside a neurology ward during a 5-year period at a single hospital. The frequency, characteristics, and outcomes for IHS patients were compared with patients who develop ischaemic stroke outside of the hospital (out-of-hospital stroke; OHS).
Results:  Forty-six percent of IHS occurred in the department of cardiology or cardiovascular surgery and 60% were associated with surgery or procedures. In comparison with the OHS patient group, the IHS patient group showed an increased frequency of cardiac disease, leukocytosis, and anemia. Cardioembolism, stroke of other determined etiologies, and an incomplete evaluation were more common in the IHS group, whereas large artery atherosclerosis was more frequent in the OHS group. The IHS group had up to a 10-fold higher mortality than the OHS group, with sepsis being the most common cause of death in the IHS group.
Conclusions:  IHS has distinct etiologies and stroke mechanisms from OHS. The prevention and management of infection could decrease mortality in IHS patients.     

Aortic Arch Atherosclerosis——An Important Potential Source Of Cerebral Embolic Stroke

Background and purpose: Recent years with use of transesophageal echography renew awareness of aortic atherosclerosis. The purpose of this study was to determine the prevalence, clinical significance, and embolic potential of thoracic aortic plaque in patients with cerebral emblism; and further study the correlation aortic plaque with carotid or heart disease. Method: 49 consecutive patients with cerebral embolism was included in this sutdy. We uscd TEE to evaluated potential source of emboli in aortic arch and heart, and duplex in carotid artery. A atherosclerotic lesion of thoracic aorta was defined as normal(O); mild plaque (1); moderate plaque (2); protruding plaque or mobile plaque (3). Result: 31(63%) patients showed evidence of AAA; 7 (14.3%) patients had mild AAA, 9 (18.4%) patients had moderate AAA and 15 (32.7%) patients had severe AAA, In these 15 patients 11 patients neither severe ICAA or embolic heart disease, the AAA may be responsible to the cerebral embolism; 33 patients had internal carotid arterial atherosclerosis(ICAA), 9 patients had embolic heart disease; Age, ICAA had significant correlated with aortic plaque. Conclusion: Aortic atherosclerosis is common in cerebral embolism. Aortic plaque might be not only responsible for some unexplained embolic event, but also for some of the embolic stroke in the group of patient do have carotid artery or heart disease. Age might be important risk factor for the development of atherosclerotic lesion in the thoracic aorta.     

Cerebral vasoconstrictor responses to serotonin after dietary treatment of atherosclerosis: implications for transient ischemic attacks

Serotonin, which is released when platelets aggregate at carotid lesions, may contribute to cerebral ischemia. Our goal was to test the hypothesis that dietary treatment of atherosclerosis reverses the augmented cerebral vasoconstrictor response to serotonin. We studied normal cynomolgus monkeys, atherosclerotic monkeys, and atherosclerotic monkeys that were fed a normal (regression) diet for 18 months. Morphometric studies indicated that the regression diet reduced intimal area in the carotid arteries by about 50-75%. Cerebral blood flow was measured with microspheres, and microvascular pressure was measured with a micropipette in pial arteries that were approximately 300 micron in diameter. Values for cerebral blood flow and arteriolar pressure were used to calculate resistance of large cerebral arteries (greater than 300 micron diameter). Infusion of serotonin produced a modest increase in the resistance of large cerebral arteries in normal monkeys. Vasoconstrictor responses to serotonin were increased more than fivefold in atherosclerotic monkeys. The major finding of the study is that dietary treatment of atherosclerosis abolishes augmented cerebral responses to serotonin.     

Cardiological diagnostic work-up in stroke patients – a comprehensive study of test results and therapeutic implications

Background and purpose:  In some Western countries, many stroke patients undergo routine tests including ECG, echocardiography, carotid ultrasound and Holter monitoring, even though they have been shown to express limited value in unselected patients. Comprehensive data on yield of tests, especially on consequences taken from positive test results, are scanty.
Methods:  Consecutive stroke patients with evidence of ischaemic lesions by imaging techniques were included. Aetiology was determined using TOAST-classifications. Rates of positive test results and their impact on drug therapy, especially anticoagulation were evaluated.
Results:  Two hundred and forty-one consecutive patients, age 69 ± 13 years were included. Positive test results were documented in 19% with 12-lead ECG, 24% with carotid ultrasound, 24% with echocardiography and never with Holter monitoring. Overall, in 41% positive test results were present. Apart from echocardiography (37%), a change of therapy resulted in 51–56% of patients with a positive test result.
Conclusions:  Even though 12-lead ECG, carotid ultrasound and echocardiography only had relatively low incidences of positive findings, their impact on management in case of positive test results was quite high. Nevertheless, future studies to select patients more appropriately are needed. In contrast, Holter monitoring had no impact and should not be used in routine evaluation of stroke patients.