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Biomedical subjects

P A Lyrer

Publications and source records attributed to P A Lyrer.

12 recordsLinked to original sources
PubMed2006

Barriers to stroke thrombolysis in a geographically defined population.

OBJECTIVE: Barriers to thrombolysis are rather assessed for hospitalized stroke patients than among geographically defined populations. In a population-based approach, we assessed (1) the utilization rate of stroke thrombolysis in the community, and (2) the significance of the chosen stroke care provider as a potential barrier to thrombolysis. METHODS: We performed a databank-based post-hoc analysis, derived from data ascertained in a prospective, population-based stroke study among the permanent residents of the canton Basel-City, Switzerland. For the cohort with an onset assessment interval (OAI) < or =3 h, we compared thrombolyzed with non-thrombolyzed patients concerning demographic variables, the National Institutes of Health stroke scale (NIHSS) score, OAI, risk factors, and the type of stroke care provider. For patients without thrombolysis despite an OAI < or =3 h, barriers to thrombolysis were compiled. RESULTS: Among 269 patients, 49 had an OAI < or =3 h (18% of all patients and 38% of those 128 patients with exactly known time of onset). Fourteen patients received thrombolysis, amounting to a utilization rate of 5.2% (95% CI 2.9-8.6) for all patients and 29% (95% CI 17-43) for the OAI < or =3-hour cohort. For the latter, thrombolyzed differed from non-thrombolyzed patients in higher NIHSS score and type of stroke care provider, but not in demographic variables, OAI, or risk factors. Fourteen of 40 patients (35%) primarily admitted to the stroke unit received thrombolysis, compared with none of 9 patients primarily treated elsewhere (p < 0.04). In the OAI < or =3-hour cohort, mild or regressing stroke severity (48%), admission to hospitals not offering thrombolysis (20%), computed tomography or laboratory contraindications (17%) and severe comorbidity (14%) were barriers to thrombolysis. CONCLUSION: In this geographically defined population, every 20th stroke patient received thrombolysis. Only a minority of patients had an OAI < or =3 h, rendering late admission the most common barrier to thrombolysis. In the OAI < or =3-hour cohort, admission to hospitals not offering thrombolysis prompted exclusion from thrombolysis as often as established contraindications. Thus, acute stroke patients should solely be brought to hospitals providing thrombolysis.

Adult↗
PubMed2005

Thrombolysis in stroke patients aged 80 years and older: Swiss survey of IV thrombolysis.

This databank-based, multicenter study compared all stroke patients with IV tissue plasminogen activator aged > or = 80 years (n = 38) and those < 80 years old (n = 287). Three-month mortality was higher in older patients. Favorable outcome (modified Rankin scale < or = 1) and intracranial hemorrhage (asymptomatic/symptomatic/fatal) were similarly frequent in both groups. Logistic regression showed that stroke severity, time to thrombolysis, glucose level, and history of coronary heart disease independently predicted outcome, whereas age did not.

Age Factors↗
PubMed2005

Life-threatening orolingual angioedema during thrombolysis in acute ischemic stroke.

BACKGROUND: Orolingual angioedema can occur during thrombolysis with alteplase in stroke patients. However, data about its frequency, severity and the significance of concurrent use of angiotensin-converting-enzyme inhibitors (ACEi) are sparse. OBJECTIVE: (1), to alert to the potentially life-threatening complication of orolingual angioedema. (2), to present CT-scans of the tongue which exclude lingual hematoma. (3), to estimate the frequency of orolingual angioedema. (4), to evaluate the risk associated with the concurrent use of ACEi. METHODS: Single center, databank-based observational study on 120 consecutive patients with i. v. alteplase for acute stroke. Meta-analysis of all stroke studies on alteplase-associated angioedema, which provided detailed information about the use of ACE-inhibitors. Across studies, the Peto odds ratio of orolingual angioedema for "concurrent use of ACEi" was calculated. RESULTS: Orolingual angioedema occurred in 2 of 120 patients (1.7%, 95% CI 0.2-5.9 %). Angioedema was mild in one, but rapidly progressive in another patient. Impending asphyxia prompted immediate intubation. CT showed orolingual swelling but no bleeding. One of 19 (5%) patients taking ACEi had orolingual angioedema, compared to 1 of 101 (1%) patients without ACEi. Medline search identified one further study about the occurrence of alteplase-associated angioedema in stroke patients stratified to the use of ACEi. Peto odds ratio of 37 (95 % CI 8-171) indicated an increased risk of alteplasetriggered angioedema for patients with ACEi (p <0.001). CONCLUSION: Orolingual angioedema is a potentially life-threatening complication of alteplase treatment in stroke patients, especially in those with ACEi. Orolingual hematoma as differential diagnosis can be excluded by CT-scan.

Acute Disease↗
PubMed2005

Diffusion weighted imaging, apparent diffusion coefficient maps and stroke etiology.

OBJECTIVE: In acute ischemic stroke, the number and distribution of lesions on diffusion weighted imaging (DWI) have been shown to give clues to the underlying pathogenetic mechanisms. The objective of this study was to determine whether lesion features on DWI differ between stroke due to large artery atherosclerosis (LAA) and cardioembolism (CE), and to assess the role of apparent diffusion coefficient maps (ADC). METHODS: We retrospectively studied 83 consecutive patients with stroke caused by either LAA (n=40) or cardioembolism (n=43). DWI lesions were characterized by number, size, distribution (i. e. lesion pattern) and signal intensity on ADC maps. In part A, all hyperintense DWI lesions regardless of their ADC were compared. In part B, only hyperintense DWI lesions with hypointense appearance on ADC maps (i. e. acute lesions) were assessed. RESULTS: Part A: The frequency of multiple hyperintense DWI lesions (LAA: 28/40, CE: 21/43; p< 0.05) and the lesion number (LAA 4.7+/- 4.9; CE: 3.1+/- 4.7; p=0.01) were higher in LAA-patients. Involvement of >1 circulation (i. e. anterior plus posterior or bilateral anterior circulations) was present in 5 LAA-patients (13 %) and 4 CE-patients (9 %). Lesion size did not differ between LAA-stroke (35.1+/- 33.7 mm) and CE-stroke (35.4+/- 27.8 mm). Part B: Multiple hyperintense DWI lesions with low ADC occurred in 23/40 LAA-patients and in 15/43 CE-patients (p<0.05). Lesions in >1 circulation occurred only in CE-stroke (n=3; 7%) and never in LAA-stroke. CONCLUSIONS: (1) Multiple ischemic lesions occur significantly more often in LAA-stroke than in CE-stroke. (2) ADC maps are important in the comparison of DWI lesion patterns; DWI lesions in >1 circulation can only be assigned to a cardioembolic etiology if they appear hypointense on ADC maps.

Aged↗
PubMed2004

The clinical significance of diffusion-weighted MR imaging in infratentorial strokes.

OBJECTIVE: To study the association between diffusion-weighted imaging (DWI) characteristics and stroke etiology, stroke severity, and functional outcome in patients with infratentorial strokes. METHODS: The authors prospectively studied 22 consecutive patients with acute infratentorial strokes. They used a blinded comparison of DWI features (number, distribution, and volume of lesions) with clinical characteristics, namely, stroke etiology (Trial of ORG 10172 in Acute Stroke Treatment [TOAST] classification), severity (NIH Stroke Scale [NIHSS]), length of stay (LOS), and functional 3-month outcome using modified Rankin Scale, Barthel Index, and a dichotomized outcome status (living at home vs institutionalization or death). RESULTS: Acute infratentorial DWI lesions were detected in 95% (21/22) of the patients. The number (p = 0.01) and the distribution (p < 0.001) of DWI lesions were correlated with stroke etiology. Patients with cardioembolic strokes (n = 5) had more DWI lesions (8.0 +/- 6.0) than those with other stroke etiologies (n = 17; 1.3 +/- 0.9; p < 0.001). Their lesion distribution differed from that of patients with noncardioembolic strokes (p < 0.001). Clinically silent, acute DWI lesions in the anterior circulation in addition to their infratentorial lesions were visualized in 3 of 5 patients with cardioembolic stroke and in none of 17 patients without sources of cardioembolism (p < 0.001). Pure infratentorial lesions were present in 15 of 17 patients with noncardioembolic strokes and in none of 5 cardioembolic stroke patients (p < 0.001). DWI lesion volume was not correlated with NIHSS score, LOS, outcome scores, or outcome status. CONCLUSION: In infratentorial strokes, multiple DWI lesions and a distribution of subsidiary, clinically silent DWI lesions in the anterior circulation suggest a cardioembolic stroke etiology. However, DWI lesion volume did not correlate with the NIHSS score and was no predictor of outcome.

Adult↗
PubMed2001

Preliminary experience with dynamic MR projection angiography in the evaluation of cervicocranial steno-occlusive disease.

The application of a contrast-enhanced, two-dimensional MR technique, which provides dynamic projection angiograms at a subsecond temporal frame rate for depiction of the cervical and intracranial arteries, was evaluated in three healthy volunteers and seven patients with various cervicocranial steno-occlusive diseases. Intra-arterial digital subtraction angiography (DSA) served as standard of reference for findings in the patients. Magnetic resonance projection angiography (MRPA) was performed on a standard 1.5-T clinical MR imaging system at intravenous injection of a single dose of contrast agent (0.1 mmol/kg GdDTPA-BMA). Sixty consecutive images of the cerebral circulation were acquired at a temporal frame rate of 900 ms per image in the coronal plane. The collateral flow and the perfusion of the compromised vessel territory were readily assessed by MPRA in patients with occlusion of the internal cerebral artery (ICA) or middle cerebral artery (MCA). The leptomeningeal collateralisation of these patients was displayed in a dynamic fashion. Furthermore, quantitative perfusion measurement provided a difference between both MCA territories in the time to peak (deltaDTTP) of the contrast bolus of 1.12 +/- 0.28 s in five patients with severe stenosis or occlusion of the ICA (healthy volunteers 0.19 +/- 0.05 s). However, important pathological findings, such as the evaluation of carotid artery stenoses and the intracranial collateral flow pattern in patients with severe carotid stenoses, were not sufficiently assessable as compared with DSA. We conclude that the possibility of obtaining simultaneously information about morphology and perfusion dynamics of the cervicocranial vessels is unique in MPRA as compared with other MR techniques. However, in the applied form, the technique is not a reliable tool for the complete evaluation of the cervicocranial vessels in patients with steno-occlusive disease.

Adult↗
PubMed2000

Quantification of blood flow in the middle cerebral artery with phase-contrast MR imaging.

The aim of this study was to assess blood flow in the middle cerebral artery (MCA) according to age, gender, and side. Eighty-eight subjects without carotid obstruction were measured for mean velocity, vessel area, and volume flow rates of both MCA with phase-contrast MR. A high-resolution sequence with a matrix of 300 x 512 and a double oblique localizing strategy was used for measurement. A mean velocity of 33 +/- 6.8 cm/s, a mean vessel area of 6.2 +/- 1.2 mm2 and a mean flow rate of 121 +/- 28 ml/min were measured in the MCA. Lower volume flow rates were seen in subjects aged over 50 years (p < 0.01). When comparing women with men, a lower vessel area (p < 0.05) of the MCA was counterbalanced by a higher velocity, resulting in no significant difference of the volume flow rate. No difference occurred between the right and the left side. Flow reduction occurs in the elderly. A lower vessel area of the MCA in women is compensated by a higher velocity.

Adult↗
PubMed2000

Long-term follow-up after extracranial internal carotid artery dissection.

OBJECTIVE: To evaluate long-term outcome after extracranial internal carotid artery dissection (eICAD) in consideration of the applied antithrombotic therapy. MATERIAL AND METHODS: Among 33 consecutive eICAD patients initially treated either with anticoagulation (n = 25) or with antiplatelets (n = 8), a standardized interview was performed after 28 +/- 22.1 months to analyze risks and benefits of both agents. Ischemic and hemorrhagic complications, occurrence of seizure and rates of arterial recanalization were compared and long-term clinical outcome was assessed using the modified Rankin Scale (mRS) and Barthel Index (BI). RESULTS: Among anticoagulated patients, 1 died due to brain herniation. In 3 patients stroke (n = 2) or TIA (n = 1) recurred. In the antiplatelet group, none died and no subsequent ischemic events happened. Hemorrhagic complications were noted in neither treatment group. Functional outcome among anticoagulated patients was BI 92 +/- 21.6 and mRS 1.48 +/- 1.50, which did not differ from patients initially treated with antiplatelets (BI 89 +/- 18.9, mRS 1.50 +/- 1.41, p > 0.05). Four anticoagulated patients developed seizures, compared to 2 patients with antiplatelets (p > 0.05). Arterial recanalization occurred in 16 of 22 antico- agulated patients with ultrasound follow-up, compared to 6 of 6 patients with antiplatelets (p > 0.05). CONCLUSION: In the absence of iatrogenic side effects, both anticoagulation and antiplatelets seem to be safe for eICAD. The rates for death and stroke were low and outcome ratings did not differ between both agents. These findings may indicate that a controlled randomized trial comparing anticoagulation and antiplatelets is ethically justified.

Adult↗
PubMed1999

Dissections after childbirth.

The occurrence of spontaneous internal carotid or vertebral artery dissection after childbirth remains rare. To our knowledge, seven cases of arterial dissection in the postpartum period have been described in the literature as single case reports. We report four additional cases of internal carotid and vertebral artery dissection in the puerperal period, documented by angiography. Physicians should consider the possibility of arterial dissection in any young patient presenting with acute ischemic stroke, including women in the postpartum period. The availability of modern noninvasive ultrasound and imaging techniques may result in earlier diagnosis and facilitate identification of this condition.

Adult↗
PubMed1997

Cerebral infarcts related to isolated middle cerebral artery stenosis.

BACKGROUND AND PURPOSE: The clinical presentation of middle cerebral artery (MCA) stenosis, a rarely diagnosed condition, is not well known. The aim of this study was to analyze the stroke patterns of patients with isolated MCA stenosis. METHODS: Twenty-two patients with cerebral infarcts due to isolated MCA stenosis were analyzed with respect to their clinical syndrome, and cerebral lesions were assessed by neuroimaging. MCA stenosis was diagnosed by transcranial Doppler sonography (TCD) in 16, by TCD and digital subtraction angiography (DSA) in 4, and by DSA alone in 2 patients. RESULTS: Ten patients (45.5%) had lacunar syndromes, suggesting small-vessel disease, and 12 patients (55.5%) showed signs and symptoms of cortical dysfunction. Cerebral CT or MRI showed no lesion in 2 patients, small deep infarcts in 10, large striatocapsular infarcts in 2, combined piomedullary and striatocapsular infarcts in 4, piomedullary branch infarcts in 3, and MCA trunk infarct in 1. CONCLUSIONS: The results suggest an association between MCA stenosis and (1) lacunar infarcts and (2) the occurrence of piomedullary MCA branch infarcts alone or in combination with subcortical infarcts. The clinical syndromes and the radiological findings correspond in most cases.

Adult↗