Abstract 13078: Evaluation of Ventricular Function in Fetus With Transposition of Great Arteries by Velocity Vector Imaging

Background: The aim of this study was to test the hypotheses that (1) fetuses with complete transposition of the great arteries (D-TGA) and Taussig-Bing anomaly (TBA) has decreased the left ventricular (LV) and right ventricular(RV) mechanical function compared with normal fetuses, and (2)the decreased myocardial mechanical function in fetal D-TGA and TBA was associated with the degree of transposition of the great arteries, pulmonary stenosis(PS) and ventricular septal defect(VSD). Methods: We retrospectively identified 49 cases of fetal D-TGA and 29 cases of fetal TBA and compared findings to 49 controls of comparable gestational age. Postprocessing analysis of the left ventricle and right ventricle were done using syngo Velocity Vector Imaging version 2.3. Global and regional longitudinal systolic peak velocity, strain and strain rate were generated. Results: (1) Comparing with control group, the global and regional longitudinal systolic peak velocity (GLV), strain (GLS) and strain rate (GLSR) of the LV and RV were decreased in the group of D-TGA and TBA (P<0.05). (2) In the group of D-TGA and TBA, the multivariate linear regression analysis, the VSD was the independent determinant of LVGLS and RVGLS (β = 0.270, P=0.014 and β = 0.465, P< 0.001). The PS was the independent determinant of RVGLSR (β = 0.090, P=0.009). Conclusion: The ventricular function of fetal D-TGA and TBA were decreased compared with control group. The PS and VSD were the independent determinant factors of the decreased LVGLS, RVGLS and RVGLSR in the fetal D-TGA and TBA.

Acute Effects of Whole-Body Vibration on Dopplerfluxometry of the Common Carotid Artery Parameters among Adult and Elderly Non-Athletes Healthy Dogs

Background: Whole-Body Vibration (WBV) is an oscillatory mechanical stimulus spreading throughout the body and considered a type of physical exercise because of the activation of the cardiovascular, musculoskeletal, and neuroendocrine systems. It is a physical exercise modality since it promotes cardiovascular resistance, increase in muscular strength and neurosensitivity, and motor coordination improvement. For use of WBV as an exercise modality for dogs, it is necessary to evaluate the Dopplerfluxometry parameters of the common carotid artery in healthy dogs in order to perform a safe protocol without inducing any cerebral alteration. This study aimed to evaluate the acute effects of WBV on systolic peak velocity (SPV), resistivity (RI), and pulsatility index (PI) of the both common carotid artery among adults and elderly non-athletes healthy dog.Materials, Methods & Results: Fourteen clinically healthy, neutered crossbreed male dogs, non-athlete were divided into two groups of seven dogs, according to the age group: Group 1 (G1)- Adult dogs: age between 12 and 84 months; Group 2 (G2)- Elderly dogs: aged over 84 months. All dogs were submitted to sessions of WBV using the protocol of 30 Hz for 5 min, followed by an increase to 50 Hz for 5 more min and ending with 5 min at 30 Hz, without rest between the variation of the vibration frequency. The systolic peak velocity (SPV), resistivity (RI), and pulsatility index (PI) of the common carotid artery were assessed in two time-points: 5 min before the WBV sessions (5PRE) and 1 min after the WBV (1POS). No significant variations in the SPS, RI, and PI of both common carotid artery of the G1 and G2 were identified. The anatomic reference for the left and right common carotid artery was the right and left extern jugulars veins, which were identified by the venous blood vessel characteristics as endothelium type, and single-phase without systolic peaks wave. Discussion: In humans, WBV is indicated to muscle size and tone increase, therefore it is believed that this modality can present a beneficial result in dogs with muscular atrophy associated with orthopedic surgeries and in cases of osteoarthritis. Irreversible brain damage can be caused by a possible hemodynamic alteration in the common carotid arteries resulted from mechanical vibrations. Parkinson’s disease patients and individuals affected by strokes that went under acute sessions of WBV showed handshake reduction and better proprioception, respectively. The beneficial effect was observed in cervix opening in dogs with metritis. The behavior of sitting of the dogs over 30 kg during WBVsessions was associated with paraparesis. This result was present in medium-size non-athletic dogs weighing from 10.1 to 17.9 kg that went through WBV for 5 consecutive days, using the same vibrating platform. No signs of discomfort during a single session of 10 min of WBV (15 and 21 Hz) were observed in healthy adult horses. Studies using mechanical vibrations on adult healthy dogs did not show significant variation RI of the renal artery. On the other hand, daily use of WBV for 5 days on dogs showed significant enhancement on RI of the femoral artery immediately after it. A single session of WBV (30 and 50 Hz did, for 15 min) do not produce undesirable effects on SPV, RI, and PI of both common carotid arteries in adult and elderly non-athletic healthy dogs.

Correlation between ductus venosus velocity and right ventricular diastolic function in fetuses with isolated single umbilical artery in third trimester

Background The cardiac diastolic functions in fetuses with isolated single umbilical artery (SUA) in the third trimester were ealuated using the spectrum of blood flow in the fetal ductus venosus (DV). Methods Color Doppler was employed to visualize the spectra of the fetal DV and tricuspid orifice in 34 fetuses with isolated SUA aged 28–39 weeks and in age-matched healthy controls. The DV flow velocities and velocity ratios were measured. The E/A ratio at the tricuspid orifice and tissue Doppler Tei index of fetal right ventricular in the two groups were measured. Results During the third trimester, the DV atrial systolic peak velocity “a” was lower in the isolated SUA group than in the control group ( P < 0.05). The correlations between the velocity ratios and the E/A ratio at the tricuspid orifice in the two groups were analyzed, and the correlation between the v/D and E/A ratios was the best (R 2 of 0.520 in the isolated SUA group and 0.358 in the control group). The correlations between the velocity ratios and the tissue Doppler Tei index of fetal right ventricular in the two groups were analyzed, and the correlation between the PIV and tissue Doppler Tei index ratios was the best (R 2 of 0.865 in the isolated SUA group and 0.627 in the control group). Conclusions In the isolated SUA group, the atrial systolic peak velocity “a” decreased, which might be related to changes in fetal cardiac functions. v/D was more closely related to the E/A ratio at the tricuspid valve and could be used to identify changes earlier in the isolated and healthy fetuses’ right ventricular diastolic functions. PIV was more closely related to the tissue doppler Tei index of fetal right ventricular and could be used to identify the isolated and healthy fetuses’ right ventricular overall functions.

Abstract 3340: Coronary Flow Velocity Pattern Immediately After Percutaneous Coronary Intervention Predicts Left Ventricular Remodeling in Patients with Acute Myocardial Infarction

Background: Studies using the Doppler guidewire have shown that coronary flow velocity (CFV) pattern in recanalized infracted arteries predicts recovery of regional left ventricular (LV) function, in-hospital complications, and long-term cardiac events. However, the relationship between the CFV pattern after reperfusion and serial changes in LV volumes is not clear. We postulated that the quantitative CFV measurement immediately after successful percutaneous coronary intervention (PCI) might be associated with the LV remodeling. To test this hypothesis, we prospectively analyzed the LV remodeling according to CFV parameters measured by the Doppler guidewire in patients with acute myocardial infarction (AMI). Methods: Consecutive 211 patients with first-time anterior AMI underwent successful PCI (<50% residual stenosis with TIMI flow grade 2–3) and coronary flow measurement with the Doppler guidewire. The CFV spectrum provided the following parameters: time-averaged peak velocity (cm/s), systolic peak velocity (cm/s), and diastolic deceleration time (ms). Left ventriculograms obtained immediately after PCI and 6 months after the infarction were analyzed to measure the end-diastolic volume index and end-systolic volume index. The LV remodeling was defined as an increase in end-diastolic volume index ≥20%. Result: The optimal cutoff values to predict LV remodeling (defined as 6-month LV dilation ≥20%) were 20 cm/s for time-averaged peak velocity, 0 cm/s for systolic peak velocity and 550 ms for diastolic deceleration time (sensitivity=0.63, specificity=0.56; sensitivity=0.76, specificity=0.85; and sensitivity=0.85, specificity=0.85, respectively). Systolic peak velocity and diastolic deceleration time correlated to the LV end-diastolic volume index obtained 6 months after AMI(r= −0.67; p<0.001 and r= −0.78; p<0.001, respectively). Conclusions: The CFV pattern appears to be an accurate predictor of LV remodeling even in patients who received successful PCI in the left anterior descending coronary artery immediately after AMI. This index, therefore, identifies a subset of patients at-risk.

Dilatation of the ductus venosus in human fetuses: ultrasonographic evidence and mathematical modeling

Autonomic regulation of blood flow through the fetal ductus venosus has been suggested, but the existence of a sphincter at the ductal entrance in human fetuses has yet to be established. In this paper two cases of apparent ductus venosus dilatation in two growth-restricted human fetuses are reported. Prolonged ultrasonographic analysis (45 min) showed rapid and substantial changes (>80%) of ductal diameters. Pulsed Doppler analysis was used to investigate flow velocity in the ductus venosus and umbilical vein for both normal and dilated conditions. Dilated conditions caused manifest modifications of velocity tracings. Systolic peak velocity in the ductus did not change visibly, whereas velocity at the atrial contraction showed evident reduction; consequently, pulsatility indexes increased. Furthermore, the umbilical vein presented flow velocity pulsations. The mean blood flow rate through the ductus seemed to increase substantially (>70%) for high dilatation. To investigate these findings further, we performed simulations of ductal dilatation by means of a lumped-parameter mathematical model of the human fetal circulation. Model results agreed with clinical evidence and confirmed the relationship between ductal dilatation and the observed velocity alterations. Simulated systolic peak velocity slightly increased for small dilatation (<30%), whereas atrial velocity was reduced when the ductus dilated. Furthermore, the model indicated that umbilical venous pressure decreases for increasing dilatation, whereas no change occurs in the central venous pressure. The present results seem to indicate the presence of active dilatation of the ductus venosus in human fetuses.

Duplex US of the External Carotid Artery

The ratio between the systolic peak velocities of the internal and common carotid arteries (vpICA/vpCCA), vpICA and grey-scale imaging measurement are generally used to evaluate internal carotid stenosis against known flow criteria in order to differentiate non-significant from significant stenosis. The same criteria are also used for evaluating the external carotid artery (ECA). Our data on 707 normal or stenotic ECA nevertheless showed that the systolic peak velocity of the normal ECA (vpECA) and its ratio to the systolic velocity of the CCA (vpECA/vpCCA) are higher than vpICA and vpICA/vpCCA. vpECA/vpCCA is about 2 in >0–49% ECA stenosis. Only in severe stenosis are the peak velocities almost comparable. The ratio between the peak end diastolic velocities (edvECA/edvCCA) and edvECA proved to be unreliable, as did grey-scale imaging measurement of the external carotid stenosis. In addition, ipsilateral internal carotid stenosis greatly affects the non-stenotic external carotid flow values, and probably has the same effect on the flow values of a stenotic external artery. Thus, external carotid flow values must be considered carefully.

Brachial arterial changes in response to wrist occlusion in normotensive and hypertensive men

Diameter, blood velocity, and flow of the brachial artery and vascular resistance of the brachial circulation were evaluated with a pulsed Doppler velocimeter before and after wrist occlusion in 8 younger and 8 older normotensive subjects and in 11 younger and 11 older hypertensive patients. Before occlusion, no differences existed between younger and older normotensives. However, in hypertensives, systolic peak velocity was higher in younger than in older hypertensives (P less than 0.001) and correlated to age in the overall patients (r = -0.57, P less than 0.01). Occlusion decreased velocity and flow and increased vascular resistance in all groups, but the change in resistance was not correlated with the base-line resistance. During occlusion, no differences existed between younger and older normotensives. However, in hypertensives mean and systolic peak velocity was higher (P less than 0.01), and vascular resistance was lower (P less than 0.01) in younger than in older patients. In hypertensive patients, during occlusion mean and systolic peak velocity were negatively correlated to age (r = -0.72, P less than 0.001; r = -0.59, P less than 0.01), and vascular resistance was positively related to age (r = +0.66, P less than 0.001). Thus wrist occlusion modified the brachial circulation in normotensive and hypertensive populations but revealed age-related differences only in hypertensive patients, suggesting a combined effect of age and hypertension on the muscle vascular bed.