Lower End-diastolic Velocities Research Articles

Uterine artery blood flow characteristics assessed during oestrus and the early luteal phase of pregnant and non-pregnant bitches

The aim of this study was to measure uterine artery blood velocity daily using Doppler ultrasonography in 10 young and 10 older clinically normal bitches throughout oestrus.Typical arterial waveforms identified in young bitches were characterised by a systolic peak and subsequent flow throughout diastole, whereas in older bitches, flow was sometimes absent in diastole. For 3days immediately prior to ovulation, at the time of declining plasma oestrogen and increasing progesterone concentrations, resistance index (RI) increased, principally associated with decreased diastolic velocity; in some bitches there was absent late diastolic flow during this time. In older bitches, the waveform appearance was more variable, with absent late and early diastolic flow observed in some cases. Mean RI was higher throughout oestrus for older bitches compared with young bitches, although both groups had a similar 3-day duration increase before ovulation. Nine of the young bitches and five of the older bitches became pregnant; litter size was smaller for the older bitches. Non-pregnant bitches: (1) were significantly older; (2) had fewer waveforms with continuous diastolic flow 2days before ovulation; (3) had lower end diastolic velocity, higher RI and fewer waveforms with continuous diastolic flow 2days after ovulation, and (4) had lower plasma progesterone concentrations 5days after ovulation. These are the first detailed observations of uterine artery blood velocity and waveform appearance throughout oestrus in bitches, and this is the first description of a link between impaired diastolic flow and reduced fertility. Assessment of uterine artery velocity could be useful to promote understanding of physiological mechanisms and could also become an important tool to assess potential infertility.

Common Carotid Flow Velocity is Associated with Cognition in Older Adults

To assess the relationship between carotid flow velocity and cognitive impairment in patients with mild-moderate (<50%) carotid artery disease. We studied 407 participants with available carotid ultrasound and cognitive measures. We related peak systolic velocity (PSV) and end diastolic velocity (EDV) of internal carotid artery (ICA) and common carotid artery (CCA) and intimal medial thickness (IMT) to Mini Mental State Examination (MMSE), Clock Draw Test (CDT), Activities of Daily Living Scale (ADL)and Montreal Cognitive Assessment (MoCA). EDV of CCA was significantly different in higher and lower MoCA (MMSE) groups. Multiple regression analysis demonstrated that lower EDV was significantly associated with lower MoCA (+0.459 per standard deviation (SD), p<0. 01 for the left; +0.539 per SD, p<0. 01 for the right) and CDT (odds ratio (OR) 0.093, p< 0.05 for the left; OR) 0.120, p<0. 01 for the right) scores. PSV of left CCA (-0.205 per SD, p<0.05) and IMT (+42.536 per SD, p< 0.001) were associated with ADL. PSV of right CCA was associated with MMSE (+0.081 per SD, p<0.001). No significant relationship between ICA flow velocity and cognitive performance was observed. Our preliminary data show that common carotid artery flow velocity was associated with cognitive performance.

Completion duplex ultrasound predicts early graft thrombosis after crural bypass in patients with critical limb ischemia

To determine if intraoperative distal graft end-diastolic velocity (EDV) using completion duplex ultrasound (CDU) predicts patency of crural bypass in patients with critical limb ischemia (CLI). Records of 116 non-consecutive patients who underwent crural revascularization with vein conduit and CDU between 1998 and 2008 were reviewed. Bypass grafts were performed for rest pain (34%) or tissue loss (66%), while 56% of the reported cases were categorized as "disadvantaged" because of compromised vein quality or diseased arterial outflow. A 10-MHz low-profile transducer was used to image the entire bypass at case completion. Technical adequacy of the grafts was verified by absence of retained valves, arteriovenous fistulas, or localized velocity increases and presence of bypass-dependent distal pulses. Modified Rutherford scores were calculated as surrogate markers of runoff resistance and compared to distal graft EDV. The primary study end point was graft patency during a 1-year posttreatment period. Patency rates were determined using Kaplan-Meier life table methodology and compared using the log-rank test. Predictors of graft patency were determined by Cox proportional hazards. Primary, primary-assisted, and secondary patency for all crural bypasses were 62%, 66%, and 70% at 1 year, respectively. When stratified by tertiles of distal graft EDV (0 - <5 cm/s, 5-15 cm/s, >15 cm/s), 1-year primary patency rates were 32%, 64%, and 84% (P = .001). Low (0 - < 5 cm/s) distal graft EDV (hazard ratio [HR], 3.3 confidence interval [CI], 1.74-6.41; P < .001), poor-quality conduit (HR, 2.5; CI, 1.19-5.21; P = .016), age <70 (HR, 2.08; CI, 1.06-4.00; P = .031), and lack of statin use (HR, 2.04; CI, 1.04-4.00; P = .038) were independent predictors of graft failure. While the modified Rutherford score correlated with distal graft EDV (P = .05), it was not an independent predictor of patency (P = .58). Predictors of low EDV (<5 cm/s) included single-vessel runoff (odds ratio [OR], 3.33; CI, 1.14-9.71; P = .027), poor conduit (OR, 2.94; CI, 1.16-7.41; P = 0.024), and diabetes (OR, 2.86; CI, 1.14-7.21; P = .025). Distal graft EDV predicts crural vein graft patency in patients with CLI. Grafts with EDV <5 cm/s remain at high risk for early failure. The impacts on patency of statins, age, and poor-quality conduit are, again, confirmed. These results highlight the value of EDV using intraoperative CDU for anticipating and, possibly, improving results of open crural revascularization.

Common Carotid End-Diastolic Velocity and Intima-Media Thickness Jointly Predict Ischemic Stroke in Taiwan

In Asian populations, few studies investigated the association between stroke and common carotid artery intima-media thickness (IMT). Our previous case-control studies showed that low end-diastolic velocity (EDV) in common carotid artery, a potential hemodynamic marker of intracranial resistance, was associated with ischemic stroke. Therefore, we investigated the relationship between both EDV and IMT and incident ischemic stroke in an Asian population. Baseline data from 3175 adults (30 years or older) in the Cardiovascular Diseases Risk Factor Two-Township Study were linked to incidental ischemic stroke status derived from insurance claims and death certificate records. Hazard ratios for risk of ischemic stroke for high IMT and low EDV values measured in common carotid artery were calculated using Cox proportional hazard models. With 9.85 years (median) of follow-up, 184 persons had ischemic stroke develop. Compared with the first tertile of IMT, hazard ratios were 2.03 (95% confidence intervals, 1.27-3.25) for the second tertile and 3.87 (95% confidence intervals, 2.36-5.69) for the third tertile. Hazard ratios of EDV were 5.31 (95% confidence intervals, 3.52-7.99; first tertile) and 1.94 (95% confidence intervals, 1.21-3.09; second tertile) compared with the third tertile. The individuals with high IMT and low EDV had >2-fold ischemic stroke risk compared to those with low IMT and high EDV (2.10; 95% confidence intervals, 1.35-3.26) after adjusting for age, sex, and traditional cardiovascular risk. Common carotid IMT and EDV jointly and independently predicted future ischemic stroke in this Taiwanese population. More prospective studies are required in various ethnic groups to understand the significance and implication of the current findings, particularly with respect to EDV.

The Validity of Reliability Measure in Threshold Perimetry

Purpose: To evaluate the color Doppler imaging (CDI) and pattern visual evoked potential (P-VEP) examinations in primary open angle glaucoma (POAG) patients and investigate the relation between flow velocities measured by CDI and P-VEP examination in POAG patients. Methods: Sixty five POAG patients and 45 control subjects underwent CDI evaluation of the ophthalmic artery (OA), short posterior ciliary artery (SPCA) and central retinal arteries (CRA). The peak systolic velocities (PSV) and end-diastolic velocities (EDV) and resistive index (RI) of all retrobulbar vessels were measured. The latency and amplitude of P100 in P-VEP were recorded. The differences of CDI and P-VEP parameters among POAG and control groups were compared. The correlations between CDI parameters, visual field indices and P-VEP in POAG patients were evaluated by Pearson's correlation analysis. Results: POAG patients had the lower EDV and higher RI in the OA, CRA and SPCA comparing with that of control subjects. Also, POAG patients had lower PSV in OA and CRA comparing with that of control subjects. The latency of P100 in VEP delayed and the amplitude of P100 decreased in the POAG patients comparing with that of the control group. The RI of OA and SPCA were negatively correlated with the mean deviation (MD) values in the POAG patients. The RI of OA was positively correlated with the PSD value in POAG patients. The MD values in POAG patients were negatively correlated with the latency time of P100. The RI of OA was positively correlated with the latency time of P100 and negatively correlated with the amplitude of P100 in the POAG patients. Conclusions: The combination of the CDI and pattern VEP techniques provides further interpretation of ocular circulatory changes in POAG patients. Further studies are needed for assessment the relationship between circulatory and neural changes.

Diagnostic Value of Color Doppler Imaging and Pattern Visual Evoked Potential in Primary Open-Angle Glaucoma

Purpose: To evaluate the color Doppler imaging (CDI) and pattern visual evoked potential (P-VEP) examinations in primary open angle glaucoma (POAG) patients investigate the relation between flow velocities measured by CDI and P-VEP examination in POAG patients. Methods: Sixty five POAG patients and 45 control subjects underwent CDI evaluation of the ophthalmic artery (OA), short posterior ciliary artery (SPCA) and central retinal arteries (CRA). The peak systolic velocities (PSV) and end-diastolic velocities (EDV) and resistive index (RI) of all retrobulbar vessels were measured. The latency and amplitude of P100 in P-VEP were recorded. The differences of CDI and P-VEP parameters among POAG and control groups were compared. The correlations between CDI parameters, visual field indices and P-VEP in POAG patients were evaluated by Pearson’s correlation analysis. Results: POAG patients had the lower EDV and higher RI in the OA, CRA and SPCA comparing with that of control subjects. Also, POAG patients had lower PSV in OA and CRA comparing with that of control subjects. The latency of P100 in VEP delayed and the amplitude of P100 decreased in the POAG patients comparing with that of the control group. The RI of OA and SPCA were negatively correlated with the mean deviation (MD) values in the POAG patients. The RI of OA was positively correlated with the PSD value in POAG patients. The MD values in POAG patients were negatively correlated with the latency time of P100. The RI of OA was positively correlated with the latency time of P100 and negatively correlated with the amplitude of P100 in the POAG patients. Conclusions: The combination of the CDI and pattern VEP techniques provides further interpretation of ocular circulatory changes in POAG patients. Further studies are needed for assessment the relationship between circulatory and neural changes.

Predictors for visual field progression and the effects of treatment with dorzolamide 2% or brinzolamide 1% each added to timolol 0.5% in primary open‐angle glaucoma

This study aims to identify progression factors in patients with primary open-angle glaucoma (POAG), including the effects of treatment with dorzolamide 2% or brinzolamide 1%, each added to timolol 0.5%. A sample of 161 POAG patients were prospectively randomized to receive either dorzolamide 2% (DT) or brinzolamide 1% (BT) b.i.d., each added to timolol 0.5%, during a 60-month, evaluator-masked study. Progression was determined by perimetric criteria. Factors associated with visual field progression were estimated using a conditional Cox hazard model with patient intraclass correlation and were expressed as hazard ratios (HRs) with 95% confidence intervals (95% CIs). Predictive baseline factors were lower diastolic blood pressure (DBP), lower mean arterial pressure (MAP), antihypertensive treatment, lower end-diastolic velocity (EDV) in the ophthalmic artery (OA) and short posterior ciliary artery (SPCA), and a higher resistivity index (RI) in the OA and SPCA. Progression risk decreased by approximately 30% and 20% with each centimetre per second increase of EDV in the OA and SPCA, respectively, from baseline to the last follow-up visit. Each RI decrease (or increase) of 0.01 unit in the OA or SPCA was associated with an approximate 20% decrease (or increase) in risk for progression. In a multivariate analysis, progression risk was significantly lower in eyes treated with DT (HR=0.65, 95% CI 0.41-0.90) compared with those treated with BT. Progression increased with lower DBP, lower MAP, antihypertensive medication, lower EDV in the OA and SPCA, and higher RI in the OA and SPCA. The risk for progression in patients treated with DT was half that in patients treated with BT.

Ocular blood flow measurements in healthy human myopic eyes

To evaluate the haemodynamic features of young healthy myopes and emmetropes, in order to ascertain the perfusion profile of human myopia and its relationship with axial length prior to reaching a degenerative state. The retrobulbar, microretinal and pulsatile ocular blood flow (POBF) of one eye of each of twenty-two high myopes (N = 22, mean spherical equivalent (MSE) ≤-5.00D), low myopes (N = 22, MSE-1.00 to-4.50D) and emmetropes (N = 22, MSE ± 0.50D) was analyzed using color Doppler Imaging, Heidelberg retinal flowmetry and ocular blood flow analyser (OBF) respectively. Intraocular pressure, axial length (AL), systemic blood pressure, and body mass index were measured. When compared to the emmetropes and low myopes, the AL was greater in high myopia (p < 0.0001). High myopes showed higher central retinal artery resistance index (CRA RI) (p = 0.004), higher peak systolic to end diastolic velocities ratio (CRA ratio) and lower end diastolic velocity (CRA EDv) compared to low myopes (p = 0.014, p = 0.037). Compared to emmetropes, high myopes showed lower OBFamplitude (OBFa) (p = 0.016). The POBF correlated significantly with the systolic and diastolic blood velocities of the CRA (p = 0.016, p = 0.036). MSE and AL correlated negatively with OBFa (p = 0.03, p = 0.003), OBF volume (p = 0.02, p < 0.001), POBF (p = 0.01, p < 0.001) and positively with CRA RI (p = 0.007, p = 0.05). High myopes exhibited significantly reduced pulse amplitude and CRA blood velocity, the first of which may be due to an OBF measurement artefact or real decreased ocular blood flow pulsatility. Axial length and refractive error correlated moderately with the ocular pulse and with the resistance index of the CRA, which in turn correlated amongst themselves. It is hypothesized that the compromised pulsatile and CRA haemodynamics observed in young healthy myopes is an early feature of the decrease in ocular blood flow reported in pathological myopia. Such vascular features would increase the susceptibility for vascular and age-related eye diseases.

Color Doppler imaging and pattern visual evoked potential in normal tension glaucoma and hypertension glaucoma

To compare the differences in color Doppler imaging (CDI) and pattern visual evoked potential (P-VEP) examinations between normal tension glaucoma (NTG) and hypertension primary open angle glaucoma (HTG) patients, and investigate the relation between flow velocities measured by CDI and P-VEP examination in NTG and HTG patients. Sixty NTG patients, 66 HTG patients and 44 control subjects underwent CDI evaluation of the ophthalmic artery (OA), short posterior ciliary artery (SPCA) and central retinal arteries (CRA). The peak systolic velocities (PSV) and end-diastolic velocities (EDV) and resistive index (RI) of all retrobulbar vessels were measured. The latency and amplitude of P100 in P-VEP were recorded from the three groups. The differences of CDI and P-VEP parameters among NTG group, HTG group and control group were compared by one-way analysis of variance. The correlations between CDI parameters and visual field indices, P-VEP and visual field indices, P-VEP and CDI parameters in NTG and HTG patients were evaluated by Pearson's correlation analysis. NTG and HTG patients had the lower EDV and higher RI in the OA, CRA and SPCA comparing with that of control subjects. NTG and HTG patients also had lower PSV in OA and CRA comparing with that of control subjects. There was no significant difference in the blood flow velocities and RI of all retrobulbar vessels between NTG and HTG patients. The latency of P100 in VEP delayed and the amplitude of P100 decreased in the NTG and HTG patients comparing with that of the control group. There was no significant difference in the latency and amplitude of P100 between the NTG and HTG patients. The RI of OA and SPCA were negatively correlated with the mean deviation (MD) values in the NTG and HTG patients. The RI of OA was positively correlated with the PSD value in the NTG and HTG patients. The MD values in the NTG and HTG patients were negatively correlated with the latency time of P100. The RI of OA was positively correlated with the latency time of P100 in NTG and HTG patients. The RI of OA was negatively correlated with the amplitude of P100 in HTG patients. No significant difference was found in the parameters of CDI and P-VEP between NTG and HTG patients. The certain parameters of CDI were correlated with P-VEP parameters in NTG and HTG patients.

Transitions of multifocal electroretinography in patients with age-related macular degeneration after combination therapy with photodynamic therapy and intravitreal bevacizumab

To compare the differences in color Doppler imaging (CDI) and pattern visual evoked potential (P-VEP) examinations between normal tension glaucoma (NTG) and hypertension primary open angle glaucoma (HTG) patients, and investigate the relation between flow velocities measured by CDI and P-VEP examination in NTG and HTG patients. Sixty NTG patients, 66 HTG patients and 44 control subjects underwent CDI evaluation of the ophthalmic artery (OA), short posterior ciliary artery (SPCA) and central retinal arteries (CRA). The peak systolic velocities (PSV) and end-diastolic velocities (EDV) and resistive index (RI) of all retrobulbar vessels were measured. The latency and amplitude of P100 in P-VEP were recorded from the three groups. The differences of CDI and P-VEP parameters among NTG group, HTG group and control group were compared by one-way analysis of variance. The correlations between CDI parameters and visual field indices, P-VEP and visual field indices, P-VEP and CDI parameters in NTG and HTG patients were evaluated by Pearson's correlation analysis. NTG and HTG patients had the lower EDV and higher RI in the OA, CRA and SPCA comparing with that of control subjects. NTG and HTG patients also had lower PSV in OA and CRA comparing with that of control subjects. There was no significant difference in the blood flow velocities and RI of all retrobulbar vessels between NTG and HTG patients. The latency of P100 in VEP delayed and the amplitude of P100 decreased in the NTG and HTG patients comparing with that of the control group. There was no significant difference in the latency and amplitude of P100 between the NTG and HTG patients. The RI of OA and SPCA were negatively correlated with the mean deviation (MD) values in the NTG and HTG patients. The RI of OA was positively correlated with the PSD value in the NTG and HTG patients. The MD values in the NTG and HTG patients were negatively correlated with the latency time of P100. The RI of OA was positively correlated with the latency time of P100 in NTG and HTG patients. The RI of OA was negatively correlated with the amplitude of P100 in HTG patients. No significant difference was found in the parameters of CDI and P-VEP between NTG and HTG patients. The certain parameters of CDI were correlated with P-VEP parameters in NTG and HTG patients.

Carotid Artery Pseudo-occlusion: Does End-diastolic Velocity Suggest Need for Treatment?

We reviewed our institution's experience with carotid artery pseudo-occlusion (CAPO), to investigate whether internal carotid artery (ICA) end-diastolic velocity (EDV) as measured by duplex ultrasonography, was a predictor of need for further intervention. From February 2003 to January 2008, 7478 patients underwent duplex ultrasonographic evaluation of their carotid arteries. Diagnosis of CAPO included the appearance of a narrow flow jet (string sign) on power doppler images, low velocities in the ICA and additional criteria listed below. Ten patients (0.13%) were identified as having a CAPO. All patients were asymptomatic and had an EDV<78 cm/s. Occlusion or functional occlusion was identified in nine patients on contrast imaging studies. Eight of these patients were treated medically without neurologic complication on follow-up. Two patients were treated with interventions and were asymptomatic at follow up. The mean follow up for the entire group was 12 months. Although this is a low volume study, there is evidence to suggest that asymptomatic patients with low EDV in the setting of carotid artery pseudo-occlusion found of duplex, may be safely managed medically.

Underestimation of Carotid Stenosis in Bradycardia

Bradycardia may lead to an underestimation of carotid stenosis by duplex ultrasonography. An 83-year-old man with asymptomatic bradycardia was referred to our institution after magnetic resonance angiography revealed greater than 90% stenosis of the proximal left internal carotid artery (ICA). Two separate carotid duplex examinations were subsequently performed at different vascular laboratories within our institution. Both studies showed elevated (but borderline for the highest category of stenosis) peak systolic velocities with relatively low end-diastolic velocities (EDVs). Angiography demonstrated more than 90% stenosis of the left ICA. Carotid endarterectomy was then performed. In conclusion, interpreting physicians and vascular ultrasound technologists should be aware of the spurious decrease in EDV that accompanies bradycardia. Further imaging may be warranted when revascularization is a consideration for bradycardic patients with borderline results on carotid duplex ultrasonography.

Blood flow changes in exfoliation

Abstract Purpose: Evaluation of orbital blood flow parameters by using color Doppler imaging in patients with unilateral exfoliation syndrome (XFS). Methods: This prospective, comparative case series included 33 unilateral XFS patients, and 33 age‐sex matched control subjects. Color Doppler imaging was used to evaluate the XFS affected (Group 1), and unaffected (Group 2) eyes that were matched with the corresponding side (Groups 3, and 4) of control subjects. A masked radiologist obtained peak systolic velocity (PSV), and end diastolic velocity (EDV) of ophthalmic (OA), central retinal (CRA), nasal posterior ciliary (NPCA) and temporal posterior ciliary arteries (TPCA) as well as mean velocity of central retinal vein (CRV). Resistive indices (RI) were calculated. Results: Orbital blood flow parameters had no statistically significant difference between Group 1, and 2 (p&gt;0.05). OA of Group 1 had significantly low PSV and EDV, and high RI compared to Group 3. OA PSV, EDV, and RI for Groups 1, and 3 were 25.3+/‐9.2 cm/sec (p=0.000), 5.8+/‐2.5cm/sec (p=0.000), 0.74+/‐0.04 (p=0.009), and 35.1+/‐11.0 cm/sec, 9.7+/‐3.5 cm/sec, 0.69+/‐0.07 respectively. The RI had a cut‐off value of 0.72 between Group 1 (95% Confidence Interval [CI] for mean, 0.72‐0.75) and Group 2 (95% CI, 0.66‐0.72). In Group 2, OA PSV and EDV also were lower than Group 4 while the RI value did not differ significantly. Blood flow values for CRA, NPCA, TPCA, and CRV did not show any significant difference between the groups (p&gt;0.05). Conclusions: Ophthalmic artery hemodynamic parameters change in both eyes of unilateral XFS patients pointing out the systemic nature of the disease. The decrease in blood flow might be due to decreased vascular compliance through progressive buildup of exfoliative material in blood vessels.

Transcranial color-coded sonography in head injury

Sir, We read with interest the recent article by Kochanowicz et al., “Detection and monitoringofcerebraldisturbanceswith transcranial color-coded sonography in patients with head injury” [1]. In this preliminaryreport,theauthorsshowthat low end-diastolic velocities and low resistance index values are associated with poor outcome in patients with moderate to severe head injury. The authorsalsostatethatreportsconcerning the use of transcranial color-coded sonography (TCCS) in traumatic brain injury (TBI) are scarce and based on small patient groups. We agree with the authors that TCCS is infrequently used in TBI patient monitoring in neurocritical care units compared to conventional transcranial Doppler sonography. In our Neurocritical Intensive Care Unit, TCCS is routinely used to monitor TBI patients. We would like to point out that along with the advantages in cerebral hemodynamic evaluations described by the authors, TCCS can monitor midline shift in patients with TBI, achieving good correlation with cranial computed tomography (CT) measurements [2]. The detection of posttraumatic carotid cavernous fistulas at a non-symptomatic stage has also been recently described [3]. We concur with the authors’ conclusions regarding the advantages of TCCS over conventional and blind transcranial Doppler sonography [4]. We appreciate the findings that Dr Krejza’s group presents on the use of TCCS in TBI patients. We expect TCCS to be more widely used in patients with head injury, as this will enhance the quality of multimonitoring of TBI patients with the aim of decreasing secondary ischemic insults.

Haemodynamic features during high‐frequency oscillatory ventilation in preterms

Aim: To compare the haemodynamic status during high‐frequency oscillatory ventilation and conventional mechanical ventilation in very preterm infants with respiratory distress syndrome. Methods: Thirty‐two neonates of less than 30 wk gestation randomly assigned to high‐frequency oscillatory ventilation (n= 15) or conventional mechanical ventilation (n= 17) had three echocardiographies and one cerebral Doppler‐echography under the same ventilation during the first 48 h of life. Results: Mean airway pressure was 2 cm H2O higher in infants ventilated with high‐frequency oscillatory ventilation at the different echocardiographies. Comparable right ventricular indexes were observed in the two groups. Reduction of the ductus arteriosus diameter and ductal closure were significant only in neonates ventilated conventionally. Left ventricular performance and left ventricular contractility did not differ between the groups. The high‐frequency group had lower end diastolic velocity and a higher resistance index in the anterior cerebral artery. Conclusion: Compared with conventional mechanical ventilation, high‐frequency oscillatory ventilation was achieved without altering cardiac function. However, the inability of the left ventricle to improve its performance in the presence of a significant ductal shunt suggests a narrow range of optimal pressures under this ventilatory mode.

Prediction of early graft failure with intraoperative completion duplex ultrasound scan.

The purpose of this study was to determine intraoperative hemodynamic parameters that predict early failure of infragenicular vein grafts with intraoperative completion duplex ultrasound scan. We reviewed the results of intraoperative duplex scans that were selectively performed after completion of 45 tibial/pedal vein bypass grafts at high risk for failure. Bypass was performed for rest pain (39%) or tissue loss (61%), and 60% of the cases were disadvantaged because of compromised vein quality or poor arterial outflow. A 10-MHz low-profile transducer was used to scan the entire graft at bypass completion. All grafts were determined to be technically adequate (absence of retained valves, arteriovenous fistulas, or localized velocity increases and the presence of bypass-dependent distal pulses). Peak systolic velocity (PSV) and end diastolic velocity (EDV) were also measured at each anastomosis, in the outflow artery and in the proximal and distal portions of each graft. Resistive indices (RI) were calculated at each measurement point (PSV-EDV/PSV). Statistical analysis was performed with unpaired t test, chi(2) test, and multivariate analyses. Twenty infragenicular vein bypass grafts (44%) thrombosed within 12 months. Intraoperative hemodynamic parameters were significantly different between grafts that remained patent or thrombosed. EDV was lower (5 +/- 1 cm/s versus 13 +/- 3 cm/s; P =.02) and RI was higher (0.90 versus 0.81; P <.01) in the proximal portions of grafts that thrombosed within 12 months. Distal EDV was also lower (6 +/- 1 cm/s versus 15 +/- 2 cm/s; P <.01) and distal RI was higher (0.89 versus 0.78; P <.01) in grafts that thrombosed. With multivariate analysis, only low distal EDV was predictive of early graft failure (P <.05). Distal bypass EDV of less than 8 cm/s predicated early graft thrombosis with 76% sensitivity and 75% specificity (positive predictive value, 71%; negative predictive value, 78%). Absence of diastolic flow (EDV of 0 cm/s) predicted early graft failure with 100% specificity and 100% positive predictive value. In this initial experience, low EDV measured with intraoperative duplex scan was associated with early thrombosis of tibial level vein grafts. When such values are observed, measures should be taken to improve graft hemodynamic parameters. Prospective study of infragenicular vein bypass grafts may better define hemodynamic parameters predictive of early graft thrombosis.

Increased intracranial resistance as reflected by low end diastolic velocity, high resistance index, and increased diameter of extracranial carotid arteries has better power than extracranial carotid atherosclerosis in predicting ischemic stroke in Chinese of Taiwan

86 Background: Peak systolic velocity (PSV) has been considered a good index of detecting high degree stenosis (&gt;50%) of carotid arteries and has been used in combination with stenosis percentage to identify high risk individual for ischemic stroke (IS). Fewer studies focused on other parameters such as end diastolic velocity (EDV), flow volume (FV), resistance index (RI), and diameter (DIA). We aimed to compare the predictive power of various Duplex ultrasonography indices on ischemic stroke in Chinese. Methods: We conducted a case-control study on 251 first-ever IS patients (age≥40) and 242 age and sex matched outpatient controls. Duplex indices of spectral analysis and image were obtained. Percentage of stenosis, plaque score (PS), PSV, EDV, RI, DIA, and FV of right carotid arteries were included the analysis. Results: Parameters of common carotid artery (CCA) were used due to its stronger predictive power of IS risk than those of internal and external CA. Higher sensitivity and specificity for IS were demonstrated for each of EDV, RI and DIA than PS, stenosis percentage, PSV, and FV. Factor analysis extracted two factors out of 5 best indices, which were intracranial resistance factor (composed of EDV, RI, and DIA) and carotid atherosclerosis factor ( PS and stenosis percentage). Significantly high age-and-sex-adjusted odds ratios for IS appeared on those subjects with low EDV (OR=4.93, p=0.0001), high RI (OR=3.26, p=0.0001), large DIA (OR=2.82, p=0.0001), or positive PS (OR=2.51, p=0.0001). Higher odds ratios (OR=10.16, p=0.0000) were occurred in those subjects with low EDV, high RI, and large DIA combined. Conclusion: An intracranial resistance component may be described by low EDV, high RI, and large DIA. We found strong associations of IS risk with EDV, RI, and DIA separately or combined. This association was much stronger than that of PS or that of stenosis percentage, indicating the significance of intracranial resistance in the pathogenesis of ischemic stroke in Chinese.

Increased intracranial resistance as reflected by low end diastolic velocity, high resistance index, and increased diameter of extracranial carotid arteries has better power than extracranial carotid atherosclerosis in predicting ischemic stroke in Chinese of Taiwan

86 Background: Peak systolic velocity (PSV) has been considered a good index of detecting high degree stenosis (>50%) of carotid arteries and has been used in combination with stenosis percentage to identify high risk individual for ischemic stroke (IS). Fewer studies focused on other parameters such as end diastolic velocity (EDV), flow volume (FV), resistance index (RI), and diameter (DIA). We aimed to compare the predictive power of various Duplex ultrasonography indices on ischemic stroke in Chinese. Methods: We conducted a case-control study on 251 first-ever IS patients (age≥40) and 242 age and sex matched outpatient controls. Duplex indices of spectral analysis and image were obtained. Percentage of stenosis, plaque score (PS), PSV, EDV, RI, DIA, and FV of right carotid arteries were included the analysis. Results: Parameters of common carotid artery (CCA) were used due to its stronger predictive power of IS risk than those of internal and external CA. Higher sensitivity and specificity for IS were demonstrated for each of EDV, RI and DIA than PS, stenosis percentage, PSV, and FV. Factor analysis extracted two factors out of 5 best indices, which were intracranial resistance factor (composed of EDV, RI, and DIA) and carotid atherosclerosis factor ( PS and stenosis percentage). Significantly high age-and-sex-adjusted odds ratios for IS appeared on those subjects with low EDV (OR=4.93, p=0.0001), high RI (OR=3.26, p=0.0001), large DIA (OR=2.82, p=0.0001), or positive PS (OR=2.51, p=0.0001). Higher odds ratios (OR=10.16, p=0.0000) were occurred in those subjects with low EDV, high RI, and large DIA combined. Conclusion: An intracranial resistance component may be described by low EDV, high RI, and large DIA. We found strong associations of IS risk with EDV, RI, and DIA separately or combined. This association was much stronger than that of PS or that of stenosis percentage, indicating the significance of intracranial resistance in the pathogenesis of ischemic stroke in Chinese.

Relationship between ocular perfusion pressure and retrobulbar blood flow in patients with glaucoma with progressive damage

PURPOSE: To evaluate the relationship between ocular perfusion pressure and color Doppler measurements in patients with glaucoma. MATERIALS AND METHODS: Twenty patients with primary open-angle glaucoma with visual field deterioration in spite of an intraocular pressure lowered below 21 mm Hg, 20 age-matched patients with glaucoma with stable visual fields, and 20 age-matched healthy controls were recruited. After a 20-minute rest in a supine position, intraocular pressure and color Doppler measurements parameters of the ophthalmic artery and the central retinal artery were obtained. Correlations between mean ocular perfusion pressure and color Doppler measurements parameters were determined. RESULTS: Patients with glaucoma showed a higher intraocular pressure ( P < .0008) and a lower mean ocular perfusion pressure ( P < .0045) compared with healthy subjects. Patients with deteriorating glaucoma showed a lower mean blood pressure ( P = .033) and a lower end diastolic velocity in the central retinal artery ( P = .0093) compared with normals. Mean ocular perfusion pressure correlated positively with end diastolic velocity in the ophthalmic artery (R = 0.66, P = .002) and central retinal artery (R = 0.74, P < .0001) and negatively with resistivity index in the ophthalmic artery (R = −0.70, P = .001) and central retinal artery (R = −0.62, P = .003) in patients with deteriorating glaucoma. Such correlations did not occur in patients with glaucoma with stable visual fields or in normal subjects. The correlations were statistically significantly different between the study groups (parallelism of regression lines in an analysis of covariance model) for end diastolic velocity ( P = .001) and resistivity index ( P = .0001) in the ophthalmic artery, as well as for end diastolic velocity ( P = .0009) and resistivity index ( P = .001) in the central retinal artery. CONCLUSIONS: The present findings suggest that alterations in ocular blood flow regulation may contribute to the progression in glaucomatous damage.

The role of common carotid artery end-diastolic velocity in near total or total internal carotid artery occlusion

To evaluate the role of the end-diastolic velocity (EDV) in the common carotid artery (CCA) as a marker of internal carotid artery (ICA) occlusion. Validation of retrospective data in a prospective clinical study. The EDV in 94 patients with total ICA occlusion and in 24 patients with high grade (95-99%) unilateral ICA stenosis identified on extracranial carotid colour-flow Duplex imaging (CFDI) and arteriography was reviewed, and was retrospectively compared to the EDV of 176 normal individuals. Identification of patients with ICA occlusion was most accurate (99.3%) with an ipsilateral EDV > or = 12 cm/s and a DIFF > or = 10 cm/s (DIFF = contralateral EDV -- ipsilateral EDV). These values were then prospectively applied to all 886 patients (67 with high grade stenosis or occlusion) who underwent CFDI at our institution during 1994. The EDV > or = 12 had a 92% sensitivity, a 99.4% negative predictive value (NPV) and a 85% specificity in distinguishing between occluded and patent ICA's. In combination with a DIFF > or = 10 was 80.4% sensitive and 97.5% specific. The positive predictive value of the EDV > or = 12 in the distinction between 95-99% ICA stenosis and ICA occlusion was 78.3%, and that of the combination was 85.4%. The EDV was rarely zero and 10% of patients with normal or minimally diseased ICA's had an EDV > or = 12 and/or a DIFF > or = 10. The EDV < or = 12 cm/s is a sensitive marker of ICA occlusion with a high NPV and in combination with the DIFF > or = 10 cm/s, is specific. Nevertheless, EDV parameters are inaccurate in the distinction of 95-99% ICA stenosis from occlusion. Low EDV can be found in a number of patients with minor or no ICA disease, particularly in those with a stroke or silent cerebral infarct.