Spontaneous and indicated preterm delivery risk is increased among overweight and obese women without prepregnancy chronic disease.

OBJECTIVE: To investigate the independent impact of prepregnancy obesity on preterm delivery among women without chronic diseases by gestational age, preterm category and parity. DESIGN: A retrospective cohort study. SETTING: Data from the Consortium on Safe Labor (CSL) in the USA (2002-08). POPULATION: Singleton deliveries at ≥23 weeks of gestation in the CSL (43 200 nulliparas and 63 129 multiparas) with a prepregnancy body mass index (BMI) ≥18.5 kg/m2 and without chronic diseases. METHODS: Association of prepregnancy BMI and the risk of preterm delivery was examined using Poisson regression with normal weight as reference. MAIN OUTCOME MEASURES: Preterm deliveries were categorised by gestational age (extremely, very, moderate to late) and category (spontaneous, indicated, no recorded indication). RESULTS: Relative risk of spontaneous preterm delivery was increased for extremely preterm among obese nulliparas (1.26, 95% CI: 0.94-1.70 for overweight; 1.88, 95% CI: 1.30-2.71 for obese class I; 1.99, 95% CI: 1.32-3.01 for obese class II/III) and decreased for moderate to late preterm delivery among overweight and obese multiparas (0.90, 95% CI: 0.83-0.97 for overweight; 0.87, 95% CI: 0.78-0.97 for obese class I; 0.79, 95% CI: 0.69-0.90 for obese class II/III). Indicated preterm delivery risk was increased with prepregnancy BMI in a dose-response manner for extremely preterm and moderate to late preterm among nulliparas, as it was for moderate to late preterm delivery among multiparas. CONCLUSIONS: Prepregnancy BMI was associated with increased risk of preterm delivery even in the absence of chronic diseases, but the association was heterogeneous by preterm categories, gestational age and parity. TWEETABLE ABSTRACT: Obese nulliparas without chronic disease had higher risk for spontaneous delivery <28 weeks of gestation.

Prognostic factors for recurrence after bilateral rectus recession procedure in patients with intermittent exotropia.

PURPOSE: The purpose of this study is to evaluate prognostic factors, specifically age, at the time of surgery, for recurrence after bilateral lateral rectus recession (BLR) in patients with intermittent exotropia. METHODS: Medical records of 511 subjects who underwent BLR procedures between the ages of 3 and 10 years with more than 12 months of follow-up were retrospectively reviewed. Patients' surgical outcomes with a deviation of less than 10 prism diopters (PD) exotropia and less than 5 PD esotropia were defined as a success. Outcomes with more than 11 PD exotropia were designated as recurrences, and those with esotropia of more than 5 PD after 3 months of surgery were noted as overcorrection. Prognostic factors for recurrence were analyzed by multivariate logistic regression test. RESULTS: Of the 511 subjects, 371 had successful surgical outcomes and 129 had recurrences, whereas 11 were found to be overcorrected. Age at surgery and immediate postoperative alignment proved to be significant factors influencing a favorable outcome by multivariate logistic regression analysis (P<0.05). However, gender, photophobia, age at onset, spherical equivalent (SE) refractive error, astigmatism, SE anisometropia, and preoperative deviation size were not significantly predictive of success (P>0.05). CONCLUSION: In BLR procedures, increasing patient age at surgery was associated with lower recurrence rates.

Xanthelasma is not associated with increased risk of carotid atherosclerosis in normolipidaemia.

OBJECTIVES: Extracranial carotid artery (ECCA) atherosclerosis is well known to be associated with cardiovascular diseases. This study aims to investigate the difference of ECCA atherosclerosis between patients with xanthelasma and control subjects in normolipidaemia. METHODS: Carotid atherosclerosis (CA) of 41 (8 males and 33 females) patients with xanthelasma and normolipidaemia, defined as levels of cholesterol below 6.21 mmol/l and triglyceride below 2.26 mmol/l, recruited from Department of Dermatology was compared with that of 85 age- and gender-matched control subjects. The extent and severity of CA were measured by high-resolution B-mode ultrasound and expressed as the mean intima-media thickness (IMT) of the common carotid artery (CCA) and ECCA plaque score. Mixed-effects model and multivariate logistic regression analyses were used to estimate the association between xanthelasma and CA. RESULTS: Patients with xanthelasma showed significantly higher levels of low-density lipoprotein cholesterol (LDL-C) levels and higher body mass index (BMI) compared with the control group. Mixed models identified age, male gender, smoking and subjects of hypertension with medication, but not the presence of xanthelasma, were associated with an increase of CCA IMT. Multivariate logistic regression analysis revealed subjects of male gender, and hypertension with medication, but not the presence of xanthelasma, associated with thicker IMT, defined as IMT >or= 75th percentile, or ECCA plaque score >or= 3. CONCLUSIONS: Normolipidaemia with xanthelasma is not significantly associated with CA, but did relate with adverse cardiovascular profiles, such as higher BMI, waist circumference and LDL-C levels.

Postchallenge hyperglycaemic spike associate with arterial stiffness.

Several large-scale epidemiological and intervention studies strongly indicate that postchallenge hyperglycaemia is the main factor associated with increasing the risk of morbidity and mortality in type 2 diabetes. However, the mechanisms that increase the risk of cardiovascular disease remain unclear. We aimed to study the relationship between postchallenge hyperglycaemia and arterial stiffness. We recruited 40 healthy subjects from a physical examination in 2005. Cardio-ankle vascular index (CAVI) was automatically calculated by VaSera VS-1000. For the reliability study, we performed the baseline study in the first 20 subjects who were returned to receive repeated measurements of CAVI 2 weeks later. The determinants of mean CAVI at different timings of oral glucose tolerance test (OGTT) study were analysed by constructing multivariate linear regression models. In reliability test, the inter-observer correlation coefficient was 0.82 for right CAVI, 0.87 for left CAVI and 0.85 for mean CAVI. Age, systolic blood pressure (SBP), diastolic blood pressure (DBP), glucose levels at 60 min (Glu60) and glucose area under the curve of OGTT (GluAUC) are found to be significantly and positively correlated to right CAVI, left CAVI and mean CAVI (p < 0.05). After adjustment for age, gender and SBP, Glu60 and GluAUC are still independent determinants of CAVI. In subjects without clinical diagnosis of type 2 diabetes, postchallenge hyperglycaemic spike is highly associated with CAVI, a good parameter of aortic stiffness, independent of age, gender and blood pressure.

Use of a near-field optical probe to locally launch surface plasmon polaritons on plasmonic waveguides: a study by the finite difference time domain method.

We used the finite difference time domain (FDTD) method to study the use of scanning near field optical microscopy (SNOM) to locally excite the nanometric plasmonic waveguides. In our calculation, the light is funneled through a SNOM probe with a sub-wavelength optical aperture and is irradiated on one end of two types of plasmonic waveguides made of 50 nm Au sphere arrays and Au nanowires. The incident light was well localized at one end of the waveguides and consequently propagated toward the other end, due to the excitation of surface plasmon polaritons. We found that the propagation length of the nanosphere array type waveguide varies from 100 to 130 nm depending on the light wavelength, the size of the probe aperture, and the launching heights. Our result shows that reducing the aperture size and using the light of the plasmon resonance wavelength of the nanosphere array could increase the propagation length and, thus, the efficiency of electromagnetic energy transportation through nanosphere arrays.

Imaging in the diagnosis and follow-up evaluation of vertebral artery dissection.

The purpose of this report is to discuss the value of ultrasonographic examination in the diagnosis and follow-up evaluation of vertebral artery dissection. We collected data on 8 patients with 11 pathologic vessels: 9 were affected intracranially and 6 were affected extracranially. Four vessels were affected in both intracranial and extracranial segments. Extracranial color-flow duplex sonography could detect abnormalities in every extracranial vertebral artery dissection. Most abnormal findings were non-specific, including severely reduced flow, absence of flow, and absence of diastolic flow. A specific finding (intramural hematoma) was noted in one artery. Abnormal transcranial color-coded sonographic findings included absence of flow, reduced velocity and reversed flow direction. Three intracranial dissecting arteries showed normal findings on transcranial color-coded sonography. Ultrasonographic follow-up study revealed evidence of improvement; this was noted almost exclusively in the extracranial segments of the vertebral artery but infrequently in the intracranial segment. Extracranial color-flow duplex sonography is sensitive in the detection of extracranial vertebral artery dissection, both in initial diagnosis and in follow-up evaluation.

Carotid and transcranial color-coded duplex sonography in different types of carotid-cavernous fistula.

BACKGROUND AND PURPOSE: Patients with carotid-cavernous fistula (CCF) may undergo direct or indirect shunting. Ultrasonography has value that is complementary to angiography in the assessment and follow-up of these patients. The aim of this study was to characterize findings provided by carotid duplex sonography (CDS) and transcranial color-coded duplex sonography (TCCD) in patients with different types of CCF. METHODS: CDS and TCCD were independently performed by technologists and neurologists. Digital subtraction or MR angiography was interpreted by a neuroradiologist. Ultrasonographic studies were categorized into 4 types: I, direct shunting only; II, direct shunting with a carotid aneurysm; III, indirect shunting only; and IV, mixed (direct and indirect) shunting. In addition to carotid and intracranial flow velocities, volume, and pulsatility, other direct and indirect ultrasound signs of shunting were evaluated. The direct sign of CCF was a mosaic flash detected by TCCD. Alteration of hemodynamic parameters on CDS and demonstration of draining veins with the use of TCCD were considered indirect signs. RESULTS: Fifteen patients (8 men, 7 women) were included in the study. According to angiographic results, patients in ultrasonographic classification types I (n=7) and II (n=3) corresponded to type A of Barrow's classification. Patients with type III (n=8) were Barrow's type C. Type IV (n=1) had a combination of Barrow's types A and C. On ultrasound, both direct and indirect signs were seen in types I, II, and IV CCF. The presence of a 2-colored oval mass divided by a zone of separation without turbulence differentiated type I from type II CCF. All patients with type III CCF had indirect signs, and only 1 patient had direct signs on TCCD. Abnormal TCCD findings were most commonly seen through the transorbital window (100%), followed by the transtemporal window (63%) and transforaminal window (40%). CONCLUSIONS: If only indirect ultrasonographic signs of CCF are present, TCCD can be used to predict an indirect CCF type on the basis of the origin of the fistula. With direct communication between carotid artery and cavernous sinus, both direct and indirect ultrasonographic signs can be found. The combination of CDS/TCCD may provide a noninvasive and reliable way to classify patients with CCF.

Ultrasonographic study and long-term follow-up of Takayasu's arteritis.

BACKGROUND AND PURPOSE: Takayasu's arteritis is an inflammatory vasculopathy involving the aorta and its major branches. Little information is available on the natural history and temporal profile of changes in the carotid vessels, the major vessels involved in Takayasu's arteritis. Duplex ultrasonography may provide a reliable and efficient tool for the characterization and follow-up of the brachiocephalic vascular changes in Takayasu's arteritis. METHODS: Sixteen female patients fulfilling the clinical diagnostic criteria for Takayasu's arteritis were studied. Mean age at onset was 23.6 years (SD = 6.0), and mean duration of follow-up was 17.1 years (SD = 11.9). The clinical features were analyzed. Only one patient had had a stroke. They had undergone at least one duplex scanning examination to evaluate the brachiocephalic vessels, including the extracranial carotid, vertebral, and subclavian arteries. Six patients underwent sequential duplex examination and long-term clinical follow-up. RESULTS: All the studied patients had subclavian artery involvement, and 11 (69%) had common carotid artery involvement. The percentage of bilateral concomitant involvement was 100% in the common carotid artery and 33% in the subclavian artery. Homogeneous circumferential intima-media thickening was commonly seen in stenotic common carotid arteries (89%). Four patients had internal carotid artery involvement (all on the left side). In the serial duplex follow-up study, 2 of 6 patients had progressive vascular stenosis with concentric thickening, rather than longitudinal spreading, in the bilateral common carotid arteries. Left-side lesions were more prominent. Most were clinically stationary, despite severe stenosis or occlusion of the common carotid arteries. CONCLUSIONS: The characteristic vascular lesions and progression changes in Takayasu's arteritis detected by duplex ultrasonography are quite different from those seen in ordinary atherosclerosis. Homogeneous circumferential intima-media thickening of the common carotid arteries is a highly specific ultrasonographic finding in patients with Takayasu's arteritis, particularly young women. Sequential duplex scanning showed vascular progression to be unpredictable and unrelated to medication in our patients. Further clinical investigations of vascular progression are warranted, and duplex scanning may provide a simple, safe, and accurate long-term means of follow-up.

Reverse jugular flow in a case of thrombosis of the brachiocephalic vein with an artificial arteriovenous fistula.

Thrombosis of the thoracic inlet veins following placement of a central venous catheter is a well-known complication, and several findings have been reported by color Doppler sonography. However, reverse jugular flow resulting from this complication is rarely mentioned and should be differentiated from another complication of iatrogenic arteriovenous fistula between neck vessels. The authors here describe a uremic patient with an artificial arteriovenous fistula in the forearm complicated with thrombosis of the ipsilateral brachiocephalic vein. Factors permitting the differential diagnosis by coloer Doppler sonography and clinical conditions are proposed.

Diagnosis and follow-up of carotid-cavernous fistulas by carotid duplex sonography and transcranial color Doppler imaging.

To investigate the suitability of extracranial carotid duplex (ECD) and transcranial color Doppler imaging (TCDI) in the diagnosis and follow-up of treatment in patients with carotid-cavernous fistulas (CCF), combined ECD and TCDI examinations were studied in seven patients with traumatic CCF. According to angiography, four patients had direct CCF, two indirect CCF and one both direct and indirect CCF. In ECD, hemodynamic parameters of the feeding artery showed an abnormally increased flow volume and decreased resistivity indices in five direct CCFs from the internal carotid artery and one indirect CCF from the external carotid artery. Direct visualization of the CCF was achieved in patients with direct CCF only, and revealed itself as a heterogeneous mosaic flash resulting from high flow velocities and turbulence. Patterns of venous drainage were detected via the transorbital and transforaminal windows in seven and five patients (four direct and one indirect CCF patients), respectively. These abnormal findings were improved or even normalized after successful treatment. In conclusion, combined ECD and TCDI examinations appear to be useful for the diagnosis and follow-up of CCF.

Extracranial carotid atherosclerosis and vascular risk factors in different types of ischemic stroke in Taiwan.

BACKGROUND AND PURPOSE: The clinical patterns of stroke and the angiographic distribution of cerebral atherosclerosis in Chinese people are different from those in whites. Studies relating carotid atherosclerosis and vascular risk factors to various types of stroke in Chinese people are lacking. METHODS: Based on clinical information, we separated 367 stroke patients living in Taiwan into four subgroups: cortical infarction (CI), subcortical infarction (SCI), vertebrobasilar artery infarction (VBAI), and cardioembolic infarction (CEI). We assessed the extent and severity of extracranial carotid artery atherosclerosis in different types of ischemic stroke using duplex ultrasonography. Vascular risk factors and carotid atherosclerosis were then correlated with each subgroup of ischemic stroke. RESULTS: Our data revealed that 32% of the CI subgroup, 3% of the SCI subgroup, 7% of the VBAI subgroup, and 21% of the CEI subgroup possessed severe carotid stenosis (> or = 50% stenosis or occlusion). The extent of atherosclerosis of extracranial carotid arteries, measured by plaque score, was also more severe in the CI subgroup than in the other subgroups. Diabetes mellitus was more frequent in the CI subgroup. Cardiomegaly and left ventricular hypertrophy were more commonly seen in the CEI subgroup. The VBAI subgroup was younger than the other subgroups. There were no differences in hypertension, prior stroke, alcohol intake, or serum levels of glucose, uric acid, hematocrit, lipids, and lipoproteins among the subgroups. CONCLUSIONS: Of the Chinese patients living in Taiwan, the extent and severity of extracranial carotid artery atherosclerosis were more prominent in patients with CI than in patients with other types of ischemic stroke. In Chinese patients with CI, severe carotid stenosis is not uncommon; in Chinese patients with SCI, however, the frequency of carotid stenosis is quite low.

Noninvasive hemodynamic classification of carotid-cavernous sinus fistulas by duplex carotid sonography.

The hemodynamic classification of the CCF has important implications for prognosis and therapy, but satisfactory criteria for such a differentiation are still lacking. We studied the application of extracranial duplex sonography in 14 cases of CCF with emphasis on the hemodynamic parameters of the RI and flow volume and made a correlation with the angiographic findings. We conclude with proposed duplex sonographic criteria for hemodynamic classification: (1) small RI with increased flow volume in the ICA: direct ICA-cavernous sinus fistulas (type A); (2) normal RI and flow volume in the ICA and ECA: dural branch of ICA-cavernous sinus fistulas (type B); (3) small RI with or without increased flow volume in the ECA: dural branch of ECA-cavernous sinus fistulas (type C) or dural branches of ICA- and ECA-cavernous sinus fistulas (type D). Application for assessment of the therapeutic effectiveness was also demonstrated.

The value of duplex and continuous wave Doppler sonography for evaluation of the extracranial vertebral arteries: a prospective comparison with angiography.

BACKGROUND: The role of duplex sonography in the detection of the extracranial vertebral arteries is not well established. The purpose of this study was to determine the practical possibilities of vascular sonography for non-invasive investigation of the vertebral arteries. METHODS: The extracranial vertebral artery was divided into the pretransverse segment, the intertransverse segment C6-C2, and the atlas loop. The first two segments were examined by duplex probe and the third segment, by continuous-wave probe. Sixty vertebral arteries were studied for detecting vessel diameter, peak systolic as well as diastolic frequency shifts, flow direction and Doppler flow characteristics. A blind angiographic comparison was also performed for the sake of confirming morphological findings and flow direction. RESULTS: Duplex imaging could detect more than 90% of the vertebral arteries. The mean value of vessel diameter was 3.3 +/- 0.6 mm for the right vertebral artery and 3.5 +/- 0.5 mm for the left. Peak systolic as well as diastolic frequency shifts expressed in KHz was 1.4 +/- 0.4 versus 1.6 +/- 0.5 and 0.5 +/- 0.2 versus 0.5 +/- 0.2 in the right and the left vertebral arteries respectively. A 74% agreement in vessel size was obtained by both duplex scanning and angiography. A 100% accuracy was obtained for blood flow direction through means of a Doppler signal. Abnormal findings included stenosis or occlusion (four arteries), hypoplasia or aplasia (two arteries), and subclavian steal phenomenon (two arteries); Six of these eight were correctly predicted by confirmation of the angiographic findings. CONCLUSIONS: A combination of duplex and continuous wave Doppler sonography was affirmed in this study as a relatively accurate screening technique for detection of vertebral artery abnormalities.

[Takayasu's arteritis: a study by vascular sonography with special emphasis on carotid duplex].

Takayasu's arteritis (TA) is a chronic inflammatory disease mainly affecting young females involving the great vessels; the aorta and its major branches. Diagnosis and delineation of patterns of involvement used to depend on intra-arterial angiography in the past. With the advent of high resolution duplex ultrasonographic technique, TA can be non-invasively inspected in the vasculitis phase. Based on our ultrasound study of cervical and lower extremity vessels, 6 patients were proved to have TA by angiography. Some characteristic carotid imaging findings can be identified at the sonographic probe detectable regions, i.e., (1) The inflammatory changes of TA mainly involved the proximal parts of 3 major cervical branches from the aortic arch, but the distal parts of them and the internal carotid arteries are relatively spared. (2) The inflammatory plaques of TA are relatively homogeneous in appearance, concentric in deposition and a long extent of involvement. Differential diagnosis between TA and atherosclerotic changes can be made by the preferential sites, echogenic properties, length of involvement and manner of proliferation. Regular follow-up by ultrasonography in 2 patients showed that response to treatment and disease progression could be easily monitored.

Subclavian steal phenomenon: a correlation between duplex sonographic and angiographic findings.

Correlation of duplex sonography, angiography of the vertebral artery, and the degree of subclavian or innominate stenosis was carried out in ten patients with the subclavian steal phenomenon. Four successive stages of Doppler waveform were identified by duplex sonography. Three angiographic patterns of decreasing severity, permanent reversal, to-and-fro motion and delayed opacification, were found. Permanent reversal angiograms corresponded to complete reversal or late transient Doppler waveforms. To-and-fro motion and delayed opacification angiograms did not necessarily have a corresponding Doppler pattern. The different stages of subclavian steal phenomenon on duplex sonography correlated significantly with the degree of subclavian or innominate stenosis. Stenosis of at least 60% was found to produce abnormal vertebral artery Doppler sonography, except in one patient. Duplex sonography is considered to be a sensitive and convenient method for detecting abnormal vertebral artery haemodynamics and the subclavian steal phenomenon, but some other factors may be important in producing the Doppler waveforms.