Cerebral Venous Steal: Blood Flow Diversion with Increased Tissue Pressure

Pranevicius, Mindaugas; Pranevicius, Osvaldas

doi:10.1097/00006123-200211000-00023

Cited by 33 publications

(27 citation statements)

References 31 publications

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“…Hypoxia may indeed induce matrix fragmentation by activation of tissue metalloproteases [1]. Therefore, initial interstitial oedema may have progressed to frank oedema in MA zones, occurring together with a marked alteration in tissue morphology, hyperplasia of epithelial cells and an increase in interstitial pressure similar to that reported for other oedematous tissues, such as solid tumours and brain oedema [12,13]. One cannot exclude that in the lung the increase in tissue pressure might also reflect an increase in alveolar pressure (auto-PEEP) that should not exceed 1-2 cmH 2 O.…”

Section: Discussionmentioning

confidence: 63%

“…The increase in tissue pressure was likely to impact on pulmonary capillaries that represent a network of parallel thin-walled, collapsible channels whose patency depends upon the pressure existing in their perimicrovascular environment, a mechanical behaviour referred to as ''Starling resistor'' [14]. Thus, it seems reasonable to hypothesise that the increase in peri-microvascular interstitial pressure may represent an important factor to decrease CVI in MA regions; the corresponding increase in regional flow resistance would then divert blood flow towards other zones, similarly to what occurs in oedematous ischaemic brain regions [12]. Moreover, in high-altitude pulmonary oedema (HAPE)-sensitive subjects exposed to hypoxia, a blood shift was found from basal towards the apical regions [15], the former being characteristically more exposed to oedema formation in humans.…”

Section: Discussionmentioning

confidence: 99%

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Interstitial pressure and lung oedema in chronic hypoxia

Rivolta¹,

Lucchini²,

Rocchetti³

et al. 2010

Eur Respir J

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We evaluated how the increase in lung interstitial pressure correlates with the pulmonary vascular response to chronic hypoxia.In control and hypoxic (30 days; 10% O 2 ) Wistar male rats, we measured: pulmonary interstitial pressure (Pip), cardiac and haemodynamic parameters by echocardiography, and performed lung morphometry on tissue specimens fixed in situ.In control animals, mean¡SD Pip, air/tissue volume ratio and capillary vascularity index in the air-blood barrier were -12¡2.03 cmH 2 O, 3.9 and 0.43, respectively. After hypoxia exposure, the corresponding values of these indices in apparently normal lung regions were 2.6¡1.7 cmH 2 O, 3.6, and 0.5, respectively. In oedematous regions, the corresponding values were 12¡4 cmH 2 O, 0.4 and 0.3, respectively. Furthermore, in normal regions, the density of pre-capillary vessels (diameter ,50-200 mm) increased and their thickness/internal diameter ratio decreased, while opposite results were found in oedematous regions. Pulmonary artery pressure increased in chronic hypoxia relative to the control (39.8¡5.9 versus 26.2¡2.2 mmHg).Heterogeneity in local lung vascular response contributes to developing pulmonary hypertension in chronic hypoxia. In oedematous regions, the decrease in capillary vascularity correlated with the remarkable increase in interstitial pressure and morphometry of the pre-capillary vessels suggested an increase in vascular resistance; the opposite was true in apparently normal regions.

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Section: Discussionmentioning

confidence: 63%

Section: Discussionmentioning

confidence: 99%

Interstitial pressure and lung oedema in chronic hypoxia

Rivolta¹,

Lucchini²,

Rocchetti³

et al. 2010

Eur Respir J

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“…A potential explanation can be found in the so-called ‘cerebral venous steal’ hypothesis [23]. In the core of the cerebral infarction, local interstitial brain tissue pressures rise producing a collapse of venules and capillaries in and around the infarcted tissue [24].…”

Section: Discussionmentioning

confidence: 99%

Flow Diversion in Transcranial Doppler Ultrasound Is Associated with Better Improvement in Patients with Acute Middle Cerebral Artery Occlusion

Kim

Meyer

Garami³

et al. 2006

Cerebrovasc Dis

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Backgound: Flow diversion (FD) can occur with an acute middle cerebral artery (MCA) occlusion. FD is thought to represent the collateral blood flow to the occluded MCA territory, but it is unclear whether or not FD lessens the stroke severity or leads to improved outcome. Methods: Patients with a proximal MCA occlusion were selected from the CLOTBUST trial data bank. FD to the anterior or posterior cerebral artery was determined using transcranial Doppler ultrasound. Stroke severity and clinical improvement were measured using the National Institutes of Health Stroke Scale (NIHSS) scores. Results: We evaluated 47 patients with an isolated M1 MCA occlusion who received intravenous tissue-type plasminogen activator (t-PA) within 3 h of symptom onset. FD was present in 83% of the patients. Median baseline NIHSS scores were 15.5 in the FD– group and 18 in the FD+ group (n.s.). Complete recanalization rates were 25 and 25.6% (n.s.). In 35 patients with a persistent occlusion, the average NIHSS score reduction was 22% (FD+) and 0.52% (FD–) during 90 min after t-PA bolus (p = 0.017), and 29 versus –25% during the first 24 h after the t-PA bolus, respectively (p = 0.01). Conclusions: In patients with persistent MCA occlusions after thrombolytic treatment, arterial blood flow diversion is associated with earlier and better neurological improvement. FD has protective effects on the ischemic brain tissue with persistent MCA occlusion.

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“…12 Venous collapse in the ischemic core and peripheral displacement of blood volume caused by venous diversion have also been studied. 13 The decline in local cerebral blood volume (CBV) and venous collapse results in increased downstream resistance that further aggravates the marginal inflow pressure of arterial collaterals. Progressive ischemia after initial increases in CBV may be explained by this moving wavefront of hemodynamic instability originating in the core and moving toward the boundary of what has been termed benign oligemia (Fig 2).…”

Section: Hemodynamicsmentioning

confidence: 99%

Imaging the future of stroke: I. Ischemia

Liebeskind

2009

Annals of Neurology

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Envisioning the future of stroke appears daunting considering the milestones already achieved in stroke imaging. A historical perspective on the developments in stroke care provides a striking narrative of how imaging has transformed diagnosis, therapy, and prognosis of cerebrovascular disorders. Multimodal imaging techniques such as CT and MRI, incorporating parenchymal depictions, illustration of the vasculature, and perfusion data, can provide a wealth of information regarding ischemic pathophysiology. Key elements of ischemic pathophysiology depicted with imaging include vascular occlusion, compensatory collateral flow, resultant hemodynamic conditions that reflect these sources of blood flow, and the neurovascular injury that ensues. The mantra of "time is brain" has been perpetuated, but this does not provide an entirely accurate reflection of ischemic pathophysiology and imaging insight shows far more than time alone. Maximizing the potential of perfusion imaging will continue to expand the nascent concept that cerebral ischemia may be completely reversible in certain scenarios. Novel modalities provide a fertile ground for discovery of therapeutic targets and the potential to assess effects of promising strategies. Beyond clinical trials, imaging has become a requisite component of the neurological examination enabling tailored stroke therapy with the use of detailed neuroimaging modalities. In this first article on ischemia, the focus is on the most recent imaging advances and exploring aspects of cerebral ischemia where imaging may yield additional therapeutic strategies. A subsequent article will review recent and anticipated imaging advances in hemorrhage. These thematic overviews underscore that imaging will undoubtedly continue to dramatically shape the future of stroke.

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Cerebral Venous Steal: Blood Flow Diversion with Increased Tissue Pressure

Cited by 33 publications

References 31 publications

Interstitial pressure and lung oedema in chronic hypoxia

Interstitial pressure and lung oedema in chronic hypoxia

Flow Diversion in Transcranial Doppler Ultrasound Is Associated with Better Improvement in Patients with Acute Middle Cerebral Artery Occlusion

Imaging the future of stroke: I. Ischemia

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