Decrease In Blood Velocity Research Articles

Prone-position computed tomography in the late phase for detecting intracardiac thrombi in the left atrial appendage before catheter ablation for atrial fibrillation.

BackgroundContrast computed tomography (CT) is a useful tool for the detection of intracardiac thrombi. We aimed to assess the accuracy of the late‐phase prone‐position contrast CT (late‐pCT) for thrombus detection in patients with persistent or long‐standing persistent atrial fibrillation (AF).MethodsEarly and late‐phase pCT were performed in 300 patients with persistent or long‐standing AF. If late‐pCT did not show an intracardiac contrast defect (CD), catheter ablation (CA) was performed. Immediately before CA, intracardiac echocardiography (ICE) from the left atrium was performed to confirm thrombus absence and the estimation of the blood velocity of the left atrial appendage (LAA). For patients with CDs on late‐pCT, CA performance was delayed, and late‐pCT was performed again after several months following oral anticoagulant alterations or dosage increases.ResultsOf the 40 patients who exhibited CDs in the early phase of pCT, six showed persistent CDs on late‐pCT. In the remaining 294 patients without CDs on late‐pCT, the absence of a thrombus was confirmed by ICE during CA. In all six patients with CD‐positivity on late‐pCT, the CDs vanished under the same CT conditions after subsequent anticoagulation therapy, and CA was successfully performed. Furthermore, the presence of residual contrast medium in the LAA on late‐pCT suggested a decreased blood velocity in the LAA ( ≤ 15 cm/s) (sensitivity = 0.900 and specificity = 0.621).ConclusionsLate‐pCT is a valuable tool for the assessment of intracardiac thrombi and LAA dysfunction in patients with persistent or long‐standing persistent AF before CA.

Quantifying the Reduction in Microcirculation Perfusion After Extracorporeal Circulation

Extracorporeal circulation (ECC) is utilized in patients in critical care undergoing procedures such as extracorporeal membrane oxygenation or cardiopulmonary bypass. While most of these procedures are used to take over function of critical organs and provide oxygen to the organism, there is a lack of quantitative models established microcirculatory changes resulting from volume redistribution and changes in vascular pressure during and post ECC. To address this problem, we have combined an intravital microscopy model using the hamster dorsal window model with a custom ECC setup. Briefly, the customized ECC setup drains blood from the left jugular vein and reinfusing into the right carotid artery using a peristaltic pump. The pump is primed with either lactate ringers (LR), polymerized human hemoglobin (PolyhHb, concentration of 10 g/dL), or polymerized human methemoglobin (PolyhMetHb). Flow rate is gradually increased up to 15% of the animal's cardiac output (CO), maintained for 90 minutes, and then gradually decreased. Systemic parameters of pressure (MAP), heart rate (HR), and blood chemistry are monitored during the study. Microcirculatory measures of diameter, velocity, and flow are taken in the dorsal window model. Microcirculatory distribution of oxygen saturation is assessed using hyperspectral imaging. All the aforementioned measurements were taken at baseline, 0 hours, 2 hours, and 24 hours post ECC. After the 24 hour time point, tissues, plasma and urine were taken to assess markers of inflammation, organ function and injury, and hemoglobin and iron toxicity. Preliminary results indicate that arterioles show a markedly decreased diameter and velocity, and consequently blood flow, and venules show an increase in diameters with a drastic decrease in blood velocity. We project that decreases in MAP and HR along with respiratory acidosis will rectify by the 24 hr time point. We project that the LR group will have the worst microcirculatory flow due to the lack of proteins and low viscosity, followed by the PolyhMethb due to its high viscosity, but no oxygen carrying capacity, and the PolyhHb having the best flow due to the high viscosity and the ability to capture and carry oxygen. We expect that these flow parameters and decreased distribution of oxygen in the microcirculation will increase post-ECC, but will still be statistically significant at the 24 hour as compared to the baseline measurements. ECC redistributes blood flow and changes pressure redistribution due to the ECC circuit and pump, which cause changes in myogenic, metabolic, and endothelial mechanisms in smaller vessels in the microcirculation, affecting blood volume to organs and tissues. These studies will further our understanding of ECC impacts on the microcirculation and increase the success rate of these procedures.

Haemodynamics of atherosclerosis: a matter of higher hydrostatic pressure or lower shear stress?

The traditional view is that low shear stress of blood flow accelerates atherosclerosis. How does a low shear stress damage the vessel or aggravate atherosclerosis? It is a puzzling question. Furthermore, shear stress of veins is similar to that of Relatively Vulnerable Zones (RVZ) of arteries, while intimal thickening of veins is not obvious as the arteries. There are many places in arterioles with lower shear stress as the decrease of blood velocity, while the thickening of arterioles is not as obvious as that of the medium-sized arteries. These issues make it unconvincing for us to explain atherogenesis with lower shear stress. According to Bernoulli fluid equation (P+1/2\r{ho}v^2+\r{ho}gh=constant), in a closed pipe full of flowing blood, at the same height, the hydrostatic pressure is inversely proportional to the second power of blood velocity. At any point of per unit mass of fluid micro cluster here, the reduction of 1/2\r{ho}v^2 would be converted into P. Therefore, hydrostatic pressure(P) is inversely proportional to v^2 in a very short distance or in the same transection of the artery. When blood micro cluster flows over a very short distance or the same transection of the artery, previous studies did not consider the conversion between 1/2\r{ho}v^2 and P. Therefore, low shear stress aggravates atherosclerosis is an appearance, and the essence is that these areas with smaller blood velocity have much bigger hydrostatic pressure, which aggravates atherosclerosis. This perfectly explains the predisposing sites of atherosclerosis.

Renal and segmental artery hemodynamic response to acute, mild hypercapnia

Profound increases (>15 mmHg) in arterial carbon dioxide (i.e., hypercapnia) reduce renal blood flow. However, a relatively brief and mild hypercapnia can occur in patients with sleep apnea or in those receiving supplemental oxygen therapy during an acute exacerbation of chronic obstructive pulmonary disease. We tested the hypothesis that a brief, mild hypercapnic exposure increases vascular resistance in the renal and segmental arteries. Blood velocity in 14 healthy adults (26 ± 4 yr; 7 women, 7 men) was measured in the renal and segmental arteries with Doppler ultrasound while subjects breathed room air (Air) and while they breathed a 3% CO2, 21% O2, 76% N2 gas mixture for 5 min (CO2). The end-tidal partial pressure of CO2 ([Formula: see text]) was measured via capnography. Mean arterial pressure (MAP) was measured beat to beat via the Penaz method. Vascular resistance in the renal and segmental arteries was calculated as MAP divided by blood velocity. [Formula: see text] increased with CO2 (Air: 45 ± 3, CO2: 48 ± 3 mmHg, P < 0.01), but there were no changes in MAP (P = 0.77). CO2 decreased blood velocity in the renal (Air: 35.2 ± 8.1, CO2: 32.2 ± 7.3 cm/s, P < 0.01) and segmental (Air: 24.2 ± 5.1, CO2: 21.8 ± 4.2 cm/s, P < 0.01) arteries and increased vascular resistance in the renal (Air: 2.7 ± 0.9, CO2: 3.0 ± 0.9 mmHg·cm-1·s, P < 0.01) and segmental (Air: 3.9 ± 1.0, CO2: 4.4 ± 1.0 mmHg·cm-1·s, P < 0.01) arteries. These data provide evidence that the kidneys are hemodynamically responsive to a mild and acute hypercapnic stimulus in healthy humans.

Power Doppler ultrasound and contrast-enhanced ultrasound demonstrate non-invasive tumour vascular response to anti-vascular therapy in canine cancer patients

Combretastatin A4-phosphate (CA4P) is an anti-vascular agent which selectively shuts down blood supply in tumours, resulting in extensive tumour necrosis. The aim of this study was to assess in vivo, non-invasive ultrasound techniques for the early evaluation of tumour perfusion following CA4P treatment of spontaneous tumours. Eight dogs that bore spontaneous tumours were enrolled and were subsequently treated with a single dose of intravenous CA4P. Perfusion of tumours was evaluated by power Doppler ultrasound (PDUS) pre-treatment (0 h), during the injection (10 min, 20 min, 30 min) and after CA4P infusion (24 and 72 h). Vascularity index (VI) of the tumour tissue was quantitatively analysed and accuracy was verified by correlation analysis with the results of immunohistochemical evaluation of microvessel density (MVD). Central and peripheral perfusion was evaluated by contrast-enhanced ultrasound (CEUS) pre-treatment and at 72 h post-treatment. Post-treatment, PDUS demonstrated a significant decrease in VI within 10 min of CA4P infusion. CEUS parameters demonstrated a significant decrease in blood velocity and volume in the central aspect of the tumour. Histology revealed a 4.4-fold reduction (p < 0.001, 95% CI [2.2,9.4]) in MVD and a 4.1-fold increase (p = 0.003, 95% CI [1.4,11.8]) in necrotic tumour tissue. A strong correlation between PDUS results and immunohistochemical results was found (Pearson R2 = 0.957, p < 0.001). Furthermore, the findings of PDUS were supported by the objective results of the CEUS analyses. These data suggest a role for ultrasound in real-time, non-invasive monitoring of tumour vascular response as an early indicator of CA4P treatment efficacy.

Effect of cervical manipulation on vertebral artery and cerebral haemodynamics in patients with chronic neck pain: a crossover randomised controlled trial

ObjectiveIt is hypothesised that cervical manipulation may increase the risk of cerebrovascular accidents. We aimed to determine whether cervical spine manipulation is associated with changes in vertebral artery and cerebrovascular...

Propofol/Remifentanil Anesthesia Might Not Alter the Middle Cerebral Artery Diameter by Digital Subtraction Angiography.

Transcranial Doppler (TCD) of the middle cerebral artery (MCA) enables the measurement of the mean blood velocity (MCAVm) and the estimation of the cerebral blood flow (CBF), provided that no significant changes occur in the MCA diameter (MCADiam). Previous studies described a decrease in the MCAVm associated with the induction of total intravenous anesthesia (TIVA) by propofol and remifentanil. This decrease in blood velocity might be interpreted as a decrease in the CBF only where the MCADiam is not modified across TCD examinations. In this observational study, we measured the MCADiam of 24 subjects (almost exclusively females) on digital subtraction angiography under awake and TIVA conditions. Across the two phases, we observed a decrease in the mean arterial blood pressure (from 84 ± 9 to 71 ± 6mmHg; p < 0.001) and heart rate (76 ± 10 vs. 65 ± 8 beats/min; p < 0.001), and a concomitant decrease in the MCAVm (61 vs. 42cm/s; p < 0.001). In contrast, the MCADiam did not vary in association with TIVA (2.3 ± 0.2 vs. 2.3 ± 0.2mm; p = 0.52). Those results suggested that in this population, no significant changes in the MCADiam are associated with TIVA.

Contrast‐Enhanced Ultrasound Examination for the Assessment of Renal Perfusion in Cats with Chronic Kidney Disease

BackgroundContrast‐enhanced ultrasound examination (CEUS) is a functional imaging technique allowing noninvasive assessment of tissue perfusion. Studies in humans show that the technique holds great potential to be used in the diagnosis of chronic kidney disease (CKD). However, data in veterinary medicine are currently lacking.ObjectivesTo evaluate renal perfusion using CEUS in cats with CKD.AnimalsFourteen client‐owned cats with CKD and 43 healthy control cats.MethodsProspective case‐controlled clinical trial using CEUS to evaluate renal perfusion in cats with CKD compared to healthy control cats. Time‐intensity curves were created, and perfusion parameters were calculated using off‐line software. A linear mixed model was used to examine differences between perfusion parameters of cats with CKD and healthy cats.ResultsIn cats with CKD, longer time to peak and shorter mean transit times were observed for the renal cortex. In contrast, a shorter time to peak and rise time were seen for the renal medulla. The findings for the renal cortex indicate decreased blood velocity and shorter total duration of enhancement, likely caused by increased vascular resistance in CKD. Increased blood velocity in the renal medulla has not been described before and may be because of a different response to regulatory factors in cortex and medulla.Conclusions and Clinical ImportanceContrast‐enhanced ultrasound examination was capable of detecting perfusion changes in cats with CKD. Further research is warranted to assess the diagnostic capabilities of CEUS in early stage of the disease process.

Evaluation of Renal Perfusion in Hyperthyroid Cats before and after Radioiodine Treatment

BackgroundHyperthyroidism and chronic kidney disease (CKD) are common in elderly cats. Consequently, both diseases often occur concurrently. Furthermore, renal function is affected by thyroid status. Because changes in renal perfusion play an important role in functional renal changes in hyperthyroid cats, investigation of renal perfusion may provide novel insights.ObjectivesTo evaluate renal perfusion in hyperthyroid cats with contrast‐enhanced ultrasound (CEUS).AnimalsA total of 42 hyperthyroid cats was included and evaluated before and 1 month after radioiodine treatment.MethodsProspective intrasubject clinical trial of contrast‐enhanced ultrasound using a commercial contrast agent (SonoVue) to evaluate renal perfusion. Time‐intensity curves were created, and perfusion parameters were calculated by off‐line software. A linear mixed model was used to examine differences between pre‐ and post‐treatment perfusion parameters.ResultsAn increase in several time‐related perfusion parameters was observed after radioiodine treatment, indicating a decreased blood velocity upon resolution of the hyperthyroid state. Furthermore, a small post‐treatment decrease in peak enhancement was present in the renal medulla, suggesting a lower medullary blood volume.Conclusions and Clinical ImportanceContrast‐enhanced ultrasound indicated a higher cortical and medullary blood velocity and higher medullary blood volume in hyperthyroid cats before radioactive treatment in comparison with 1‐month post‐treatment control.

Retinal vessel oxygen saturation in healthy subjects and early branch retinal vein occlusion.

To measure the retinal oxygen saturation in healthy subjects and early branch retinal vein occlusion (BRVO) in Chinese population. The retinal vessel oxygen saturation of the healthy subjects and BRVO patients were measured by a noninvasive retinal oximeter (Oxymap ehf., Reykjavik, Iceland). The study included 22 patients with unilateral BRVO (mean age: 55.1±8.8y) in the study group and 91 healthy participants (mean age: 37.5±14.0y) in the control group. In the healthy individuals, mean arterial and venous oxygen saturation were significantly (P<0.001) higher in the superior nasal quadrant (98.5%±10.1% and 57.3%±8.7%, respectively) than in the inferior nasal quadrant (94.2%±9.0% and 54.1%±9.6%, respectively), followed by the superior temporal quadrant (89.1%±10.1% and 51.9%±8.9%, respectively) and the inferior temporal quadrant (86.4%±9.4% and 46.6%±9.6%, respectively). In patients with ischemic BRVO, arterial oxymetric values were significantly higher and venous measurements significantly lower for the affected vessel (107.5%±9.7% and 46.4%±14.2%, respectively) than the unaffected vessel in the same eye (99.2%±12.2% and 55.5%±7.9%, respectively) and as compared to the vessel in the unaffected fellow eye (93.1%±6.9% and 55.7%±6.8%) (P=0.005 and P=0.02, respectively). In the patients with non-ischemic BRVO, mean venous oxygen saturation was lower in the affected vein (39.8%±12.2%) than in the unaffected vessels of the same eye (50.8%±10.5%) and in the fellow eye (58.21%±5.7%) (P=0.03). Mean arterial oxygen saturation did not differ significantly (P=0.42) between all three groups. In patients with BRVO, the venous oxygen saturation in the affected vessels is decreased potentially due to decreased blood velocity and flow. Interestingly, the arterial oxygen saturation in eyes with ischemic BRVO is increased in the affected arteries.

Effects of Habitual Cigarette Smoking on Retinal Circulation in Patients With Type 2 Diabetes.

To examine the long-term effects of cigarette smoking on retinal circulation in patients with type 2 diabetes. Seventy-four patients with type 2 diabetes mellitus and minimal (no or mild nonproliferative) diabetic retinopathy (DR) were evaluated. These patients with type 2 diabetes were divided into three groups based on their smoking history: current smokers (n = 19), past smokers (n = 20), and never smoked (n = 35). The retinal circulatory parameters were measured with laser Doppler velocimetry and were compared among the groups. There were significant decreases in the retinal blood flow (RBF; 8.9 ± 2.9 vs. 11.6 ± 3.1 μL/min, P = 0.009) with decreased blood velocity (V; 29.6 ± 6.8 vs. 37.8 ± 9.0 mm/s, P = 0.003) but no difference in the vessel diameter (D; 112.0 ± 11.9 vs. 113.7 ± 8.6 μm, P = 0.57) in the current smokers compared with those who never smoked. There were no differences in the RBF, blood V, and vessel D in the past smokers compared with those who never smoked and current smokers. Multiple regression analysis showed that the creatinine level was correlated negatively with the RBF and that current smoking was significantly and independent correlated with decreased RBF. Our results indicated that the blood V and RBF in the retinal arterioles may decrease in patients with type 2 diabetes who are chronic smokers, suggesting that chronic smoking may be associated with decreased RBF, probably via lower blood V in the retinal arterioles in early-phase DR.

Interventioneller Vorhofohrverschluss bei Vorhofflimmer-Patienten mit hohem Blutungsrisiko

Atrial fibrillation is the most common sustained cardiac arrhythmia worldwide. The left atrial appendage (LAA) is the main source of thrombi caused by atrial fibrillation because of decreased blood velocity. These thrombi can cause thrombembolic events in leaving the LAA into the systemic circulation. For preventing thromboembolic events a long-term oral anticoagulation therapy is recommended. The interventional LAA closure is a guideline appropriate therapy option for patients with non-valvular atrial fibrillation that cannot be treated with long-term oral anticoagulation. Thereby the LAA is sealed with an implant. This therapy has shown efficient prophylaxis of thrombembolic events with safe performance in several studies.

Quantification of left atrial flow velocity distribution in atrial fibrillation using 4D flow MRI

Background Atrial fibrillation (AF) is an arrhythmia characterized by irregular electrical activity in the left atrium (LA). Thromboembolism is the most serious complication of AF, usually manifesting as stroke or systemic embolism (1). This is thought to be linked to the increased risk of thrombus formation in the LA due to a decrease in blood velocity (stasis) or flow abnormalities. A better appreciation of the underlying mechanisms and risk factors for thrombus formation in the individual patient are needed to improve risk stratification and therapy planning. Using 4D-flow MRI, time resolved blood velocity measurements can be made in patients with AF. The aim of this study was to compare LA velocity distributions in different groups of AF patients. We hypothesize that persistent AF results in more deranged LA flow patterns with reduced velocities which may be related to an increased risk of thrombus formation and thus stroke. Methods MRI data were acquired from 31 AF patients (mean age 63+/-10.5) from two groups (n=21 post-treatment, in sinus rhythm, n=10 in persistent AF). Each subject underwent gated 4D-Flow MRI on 1.5T and 3T MR systems (Siemens, Erlangen, Germany). After noise filtering, Maxwell, and eddy current correction, time resolved pathlines were emitted from planes placed manually over the pulmonary veins at the junction with the LA (Fig 1). The LA was segmented and the distribution of velocities was quantified by histogram analysis. Mean velocities were calculated for each subject group. In addition number of voxels with velocities greater than 0.2m/s was calculated. The selection of the velocity threshold was based on previous TEE results which found that systolic LA velocities less than 0.2m/s constitute a risk factor for stroke (2). Results Qualitative observation of the blood flow patterns in patients showed very different patterns between those subjects imaged in sinus rhythm and those in persistent AF. Fig 1 displays clear differences in blood flow at end systole (A,D), early diastole (B,E), and mid diastole (C,F) for a post-intervention AF patient in sinus rhythm and in persistent AF. The quantitative results from all subjects are summarized in fig 2. Patients with persistent AF had a mean blood flow of 0.14±0.03m/s, lower than AF patients in sinus rhythm (0.19±0.04m/s, p=0.006). 14% of the velocity values for patients in AF were greater than 0.2m/s, lower than patients in sinus (35%, p=0.004).

The impact of cataract on the quantitative, non-invasive assessment of retinal blood Flow

The aim of the study was to determine the impact of cataract on the quantitative, non-invasive assessment of retinal blood flow assessed by bidirectional laser Doppler flowmetry and simultaneous vessel densitometry. Ten patients scheduled for extracapsular cataract extraction using phacoemulsification and intraocular lens implantation between the ages of 61 and 84 (mean age 73 years, SD ± 8) were prospectively recruited. Two visits were required to complete the study; one visit prior to extracapsular cataract extraction and one at least 6 weeks after the surgery to allow for sufficient postoperative recovery. The severity of cataract was documented using the Lens Opacity Classification System (LOCS, III) at the first visit. Retinal arteriolar hemodynamics were measured at both visits using the high-intensity setting of the Canon Laser Blood Flowmeter. All eyes showed no clinical signs of postoperative intraocular inflammation. The quantitative assessment of retinal arteriolar diameter and blood flow were reduced following extracapsular cataract extraction (Wilcoxon signed-rank test, p = 0.022 and p=0.028, respectively); however, centreline blood velocity was not significantly changed (Wilcoxon signed-rank test, p=0.074). Intraocular pressure was unchanged pre- and postcataract extraction. Retinal vessel densitometry assessment in the presence of cataract results in the erroneous elevation of the diameter measurement and thereby the calculation of blood flow. The bidirectional Doppler assessment of blood velocity appears to be more robust to light scatter induced by cataract. Care needs to be exercised in the interpretation of studies of retinal vessel diameter or blood flow that utilize similar densitometry techniques.

Interactive blood-coil simulation in real-time during aneurysm embolization

Over the last decade, remarkable progress has been made in the field of endovascular treatment of aneurysms. Technological advances continue to make it possible for a growing number of patients with cerebral aneurysms to be treated with a variety of endovascular strategies, essentially using detachable platinum coils. Yet, coil embolization remains a very complex medical procedure for which careful planning must be combined with advanced technical skills in order to be successful. In this paper, we describe a complete process for patient-specific simulations of coil embolization, from mesh generation with medical datasets to computation of coil-flow bilateral influence. We propose a new method for simulating the complex blood flow patterns that take place within the aneurysm, and for simulating the interaction of coils with this flow. This interaction is twofold, first involving the impact of the flow on the coil during the initial stages of its deployment, and second concerning the decrease of blood velocity within the aneurysm, as a consequence of coil packing. We also propose an approach to achieve real-time computation of coil-flow bilateral influence, necessary for interactive simulation. This in turns allows to dynamically plan coil embolization for two key steps of the procedure: choice and placement of the first coils, and assessment of the number of coils necessary to reduce aneurysmal blood velocity and wall pressure. Finally, we provide the blood flow simulation results on several aneurysms with interesting clinical characteristics both in 2D and 3D, as well as comparisons with a commercial package for validation. The coil embolization procedure is simulated within an aneurysm, and pre- and post-operative status is reported.

Murine Cerebral Malaria Is Associated with a Vasospasm-Like Microcirculatory Dysfunction, and Survival upon Rescue Treatment Is Markedly Increased by Nimodipine

Brain hemodynamics in cerebral malaria (CM) is poorly understood, with apparently conflicting data showing microcirculatory hypoperfusion and normal or even increased blood flow in large arteries. Using intravital microscopy to assess the pial microvasculature through a closed cranial window in the murine model of CM by Plasmodium berghei ANKA, we show that murine CM is associated with marked decreases (mean: 60%) of pial arteriolar blood flow attributable to vasoconstriction and decreased blood velocity. Leukocyte sequestration further decreased perfusion by narrowing luminal diameters in the affected vessels and blocking capillaries. Remarkably, vascular collapse at various degrees was observed in 44% of mice with CM, which also presented more severe vasoconstriction. Coadministration of artemether and nimodipine, a calcium channel blocker used to treat postsubarachnoid hemorrhage vasospasm, to mice presenting CM markedly increased survival compared with artemether plus vehicle only. Administration of nimodipine induced vasodilation and increased pial blood flow. We conclude that vasoconstriction and vascular collapse play a role in murine CM pathogenesis and nimodipine holds potential as adjunctive therapy for CM.

Cerebral Malaria: A Vasculopathy

Cerebral Malaria: A Vasculopathy

Reduced red blood cell velocity in nail-fold capillaries as a sensitive and specific indicator of microcirculation injury in systemic sclerosis

To assess red blood cell velocity in finger nail-fold capillaries using video capillaroscopy in patients with SSc and other collagen diseases. This study included 127 patients with SSc as well as patients with SLE (n = 33), DM/PM (n = 21), RA (n = 13) and APS (n = 12), and 20 healthy subjects. Red blood cell velocity was evaluated using frame-to-frame determination of the position of capillary plasma gaps. The mean red blood cell velocity was significantly decreased in patients with SSc compared to healthy controls (63.0% reduction) and patients with other conditions. Mean blood velocity was similar between patients with dcSSc and lcSSc. Importantly, even SSc patients with normal or non-specific nail-fold video capillaroscopic (NVC) patterns or a scleroderma early NVC pattern exhibited a significantly lower red blood cell velocity compared to healthy controls (51.7 and 61.4% reduction, respectively) or patients with other conditions, despite normal or mild capillary changes. Patients with the scleroderma active and late NVC pattern showed a more decreased blood velocity (65.5 and 66.2% reduction, respectively). This reduced blood velocity was significantly associated with NVC findings, including capillary ramification and capillary loss. Although remarkably reduced velocity was observed in SSc patients with intractable digital ulcers (72.1% reduction), it was significantly improved by lipo-prostaglandin E(1) (lipo-PGE(1)) infusion. Our results suggest that reduced blood velocity is a hallmark of SSc. Furthermore, measurement of red blood cell velocity may be useful in evaluating therapeutic effects on microcirculation.

OC117: Are double pulsations in the umbilical vein equivalent to a‐wave reversal in the ductus venosus in the management of IUGR?

Objectives: Doppler waveforms of the Ductus Venosus (DV) demonstrate two periods of decreased blood velocity. These occur during isovolumetric relaxation at the end of ventricular systole and during atrial contraction at the end of ventricular diastole (a wave). In IUGR fetuses, both the isovolumetric relaxation velocity (IRV) and the end-diastolic velocity (EDV) may become abnormal. The hypothesis of this study is that in severely premature IUGR fetuses, Doppler assessment of both the IRV and the EDV allows a more accurate prediction of fetal outcome than A/REDF alone. Methods: DV Doppler was serially studied in 49 severely premature IUGR fetuses from diagnosis until demise or delivery. DV waveforms were assessed quantitatively for peak systolic velocity (PSV), IRV, and EDV and qualitatively for forward or A/REDF. The SIA Index [PSV/(IRV+EDV)] was calculated for each fetus and compared to fetal/neonatal outcomes. Data was analyzed by Kruskal-Wallis non-parametric one-way ANOVA with post-hoc Mann-Whitney U test. Results: There were 8 fetal demises (FD), 9 neonatal demises (ND), and 32 neonates survived (NS) at the time of hospital discharge. An ROC curve for the SIA Index in all cases showed less than −1.25 correlated with FD and greater than −1.25 correlated with live birth with 100% sensitivity and 100% specificity. A second ROC curve of live births showed less than 2.07 correlated with NS and greater than 2.07 correlated with ND with a sensitivity of 67% and a specificity of 94%. DV A/REDF correlated with FD and ND with sensitivities of 88% and 78%, respectively, and with NS 32%. Of the 32 NS, 11 (34%) possessed A/REDF at some time, with a median of 11 days before delivery. Conclusions: The SIA Index is a novel Doppler parameter in the assessment of severely premature IUGR fetuses that allows a much more accurate prediction of fetal outcome compared to A/REDF alone. Assessment of the SIA Index should therefore be considered part of the evaluation of IUGR fetuses.

Middle cerebral artery peak systolic velocity: a new Doppler parameter in the assessment of growth‐restricted fetuses

The aims of this study were to determine if there is a relationship between middle cerebral artery (MCA) peak systolic velocity (PSV) and perinatal mortality in preterm intrauterine growth-restricted (IUGR) fetuses, to compare the performance of MCA pulsatility index (PI), MCA-PSV and umbilical artery (UA) absent/reversed end-diastolic velocity (ARED) in predicting perinatal mortality, to determine the longitudinal changes that occur in MCA-PI and MCA-PSV in these fetuses, and to test the hypothesis that MCA-PSV can provide additional information on the prognosis of hypoxemic IUGR fetuses. This was a retrospective cross-sectional study of 30 IUGR fetuses (estimated fetal weight < 3(rd) percentile; UA-PI > 95% CI) in which the last MCA-PI, MCA-PSV and UA values were obtained within 8 days before delivery or fetal demise. Among the 30 fetuses, there were 10 in which at least three consecutive measurements were performed before delivery and these were used for a longitudinal study. MCA-PSV and MCA-PI values were plotted against normal reference ranges and were considered abnormal when they were above the MCA-PSV or below the MCA-PI reference ranges. Gestational age at delivery ranged between 23 + 1 and 32 + 5 (median, 27 + 6) gestational weeks. Birth weight ranged from 282 to 1440 (median, 540) g. There were 11 perinatal deaths. Forward stepwise logistic regression indicated that MCA-PSV was the best parameter in the prediction of perinatal mortality (odds ratio, 14; 95% CI, 1.4-130; P < 0.05) (Nagerlke R(2) = 31). In the 10 fetuses studied longitudinally, an abnormal MCA-PI preceded the appearance of an abnormal MCA-PSV. In these fetuses, the MCA-PSV consistently showed an initial increase in velocity; before demise or the appearance of a non-reassuring test in seven fetuses, there was a decrease in blood velocity. The MCA-PI presented an inconsistent pattern. In IUGR fetuses, the trends of the MCA-PI and MCA-PSV provide more clinical information than does one single measurement. A high MCA-PSV predicts perinatal mortality better than does a low MCA-PI. We propose that MCA-PSV might be valuable in the clinical assessment of IUGR fetuses that have abnormal UA Doppler.