Early Diagnosis of Carotid Stenosis by Ultrasound Doppler Investigations: A Classification Method for the Hemodynamic Parameter

Pulsed Wave Doppler (PWD) is a traditional ultrasound technique used for the diagnosis of cardiovascular disease. The conventional diagnostic method is based on hemodynamic parameters obtained from the PW spectrum. However, it relies on the clinical experience of sonographers, and especially focusing on severe carotid stenosis. This paper proposes a classification method for the hemodynamic parameter using the RUSBoost algorithm. The proposed method improves the performance of RUSBoost by setting the empirical weight of each sample. The experimental results show that the proposed method reaches the accuracy of 90.1%, the sensitivity of 70%, and the specificity of 94%, which are 4%, 6%, and 2% higher than the original RUSBoost respectively. In addition, the proposed method is objective, since the empirical weights are computed based on Mahalanobis distance without any expert input. It can be used for the early detection of cardiovascular disease.

Hemodynamic changes in superficial arteriovenous malformation surgery measured by intraoperative ICG fluorescence videoangiography with FLOW 800 software

Background: Arteriovenous malformation(AVM) have long-term “blood stealing” characteristics, which result in complicated hemodynamic features. To analyze the application of intraoperative indocyanine green angiography with FLOW 800 software in AVM surgeries.Methods: Data on 17 patients undergoing surgery with ICG fluorescence were collected. To analyze the hemodynamic features of AVM and the influence on the peripheral cortex of AVM resection, we assessed the following hemodynamic parameters: maximum intensity, slope of rise, time to half-maximal fluorescence, and transit time from arteries to veins.Results：In the 17 superficial AVMs studied, the time delay color mode of FLOW 800 software was superior to the traditional playback mode for identifying feeding arteries, draining veins, and their relation to normal cortical vessels.The maximum fluorescence intensity and slope of the ICG fluorescence curve of feeder arteries and draining veins were higher than those of normal peripheral vessels (P < 0.05). The transit times in AVMs were significantly shorter than those in normal peripheral vessels (P < 0.05).After AVM resection, cerebral flow increased in the cortex, and local cycle time become longer, although the differences were not significant (P > 0.05).Conclusions:Hemodynamic parameter analysis provided quality guidance for the resection of AVMs and could also be used in estimating changes in blood flow in the local cortex to identify abnormal hyperperfusion and residual nidus.

Hemodynamic changes in superficial arteriovenous malformation surgery measured by intraoperative ICG fluorescence videoangiography with FLOW 800 software

To analyze the application of intraoperative indocyanine green (ICG) angiography with FLOW 800 software in arteriovenous malformation (AVM) surgeries. Data on 17 patients undergoing surgery with ICG fluorescence were collected. To analyze the hemodynamic features of AVM and the influence on the peripheral cortex of AVM resection, we assessed the following hemodynamic parameters: maximum intensity, slope of rise, time to half-maximal fluorescence, and transit time from arteries to veins. In the 17 superficial AVMs studied, the time delay color mode of FLOW 800 software was superior to the traditional playback mode for identifying feeding arteries, draining veins, and their relation to normal cortical vessels.The maximum fluorescence intensity and slope of the ICG fluorescence curve of feeder arteries and draining veins were higher than those of normal peripheral vessels (P < 0.05). The transit times in AVMs were significantly shorter than those in normal peripheral vessels (P < 0.05).After AVM resection, cerebral flow increased in the cortex, and local cycle time become longer, although the differences were not significant (P > 0.05). Hemodynamic parameter analysis provided quality guidance for the resection of AVMs and could also be used in estimating changes in blood flow in the local cortex to identify abnormal hyperperfusion and residual nidus.

High wall shear stress beyond a certain range in the parent artery could predict the risk of anterior communicating artery aneurysm rupture at follow-up

OBJECTIVEAmong clinical and morphological criteria, hemodynamics is the main predictor of aneurysm growth and rupture. This study aimed to identify which hemodynamic parameter in the parent artery could independently predict the rupture of anterior communicating artery (ACoA) aneurysms by using multivariate logistic regression and two-piecewise linear regression models. An additional objective was to look for a more simplified and convenient alternative to the widely used computational fluid dynamics (CFD) techniques to detect wall shear stress (WSS) as a screening tool for predicting the risk of aneurysm rupture during the follow-up of patients who did not undergo embolization or surgery.METHODSOne hundred sixty-two patients harboring ACoA aneurysms (130 ruptured and 32 unruptured) confirmed by 3D digital subtraction angiography at three centers were selected for this study. Morphological and hemodynamic parameters were evaluated for significance with respect to aneurysm rupture. Local hemodynamic parameters were obtained by MR angiography and transcranial color-coded duplex sonography to calculate WSS magnitude. Multivariate logistic regression and a two-piecewise linear regression analysis were performed to identify which hemodynamic parameter independently characterizes the rupture status of ACoA aneurysms.RESULTSUnivariate analysis showed that WSS (p < 0.001), circumferential wall tension (p = 0.005), age (p < 0.001), the angle between the A1 and A2 segments of the anterior cerebral artery (p < 0.001), size ratio (p = 0.023), aneurysm angle (p < 0.001), irregular shape (p = 0.005), and hypertension (grade II) (p = 0.006) were significant parameters. Multivariate analyses showed significant association between WSS in the parent artery and ACoA aneurysm rupture (p = 0.0001). WSS magnitude, evaluated by a two-piecewise linear regression model, was significantly correlated with the rupture of the ACoA aneurysm when the magnitude was higher than 12.3 dyne/cm2 (HR 7.2, 95% CI 1.5–33.6, p = 0.013).CONCLUSIONSWSS in the parent artery may be one of the reliable hemodynamic parameters characterizing the rupture status of ACoA aneurysms when the WSS magnitude is higher than 12.3 dyne/cm2. Analysis showed that with each additional unit of WSS (even with a 1-unit increase of WSS), there was a 6.2-fold increase in the risk of rupture for ACoA aneurysms.

Pulse Pressure Variation Can Predict the Hemodynamic Response to Pneumoperitoneum in Dogs: A Retrospective Study

Pneumoperitoneum may induce important hemodynamic alterations in healthy subjects. Pulse pressure variation (PPV) is a hemodynamic parameter able to discriminate preload dependent subjects. Anesthesia records of dogs undergoing laparoscopy were retrospectively evaluated. The anesthetic protocol included acepromazine, methadone, propofol and isoflurane administered with oxygen under mechanical ventilation. The hemodynamic parameters were considered five minutes before (BASE) and ten minutes after (P10) the pneumoperitoneum. Based on the cardiac index (CI) variation, at P10, dogs were classified as sensitive (S group, CI ≤ 15%) and non-sensitive (NO-S group). Data were analyzed with the ANOVA test and the ROC curve (p < 0.05). Fifty-five percent of dogs (S) had a reduction of CI ≥ 15% at P10 (2.97 ± 1.4 L/min/m2) compared to BASE (4.32 ± 1.62 L/min/m2) and at P10 in the NO-S group (4.51 ± 1.41 L/min/m2). PPV at BASE was significantly higher in the S group (22.4% ± 6.1%) compared to the NO-S group (10.9% ± 3.3%). The ROC curve showed a threshold of PPV > 16% to distinguish the S and NO-S groups. PPV may be a valid predictor of the hemodynamic response to pneumoperitoneum in dogs. A PPV > 16% can identify patients that may require fluid administration before the creation of pneumoperitoneum.

Quantification of hemodynamic irregularity using oscillatory velocity index in the associations with the rupture status of cerebral aneurysms

BackgroundComplex and unstable flow patterns are reported to be associated with the rupture status of cerebral aneurysms, while their evaluation depends on qualitative analysis of streamlines of bloodflow. Oscillatory velocity index (OVI) is a hemodynamic parameter to quantify flow patterns. The aim of this study is to elucidate the associations between OVI and the rupture status of cerebral aneurysms.MethodsOne hundred and twenty-nine ruptured and unruptured cerebral aneurysms were analyzed with computational fluid dynamics under pulsatile flow conditions. With the use of median value of OVI, all aneurysms were divided into high and low OVI groups. Statistical analysis was performed to compare rupture status, and morphological and hemodynamic parameters between the two groups.ResultsThe median value of OVI was 0.006. High OVI was more likely observed in ruptured aneurysms (P=0.028) and associated with irregular shape, complex flow patterns, and unstable flow patterns (P<0.001, respectively). In morphological parameters, maximum size, aspect, projection, size, and volume-to-ostium area ratios were significantly higher in the high OVI group (P<0.001, respectively). In hemodynamic parameters, wall shear stress and wall shear stress gradient were significantly lower, and oscillatory shear index and gradient oscillatory number were significantly higher in the high OVI group (P<0.001, respectively).ConclusionHigh OVI was associated with rupture status, and morphological and hemodynamic characteristics of ruptured aneurysms. These results indicate that OVI may serve as a valuable hemodynamic parameter for diagnosing rupture status and risks of aneurysms.