Doppler Variables Research Articles

Quantification of mitral valve regurgitation in dogs with degenerative mitral valve disease by use of the proximal isovelocity surface area method

To determine the within-day and between-day variability of regurgitant fraction (RF) assessed by use of the proximal isovelocity surface area (PISA) method in awake dogs with degenerative mitral valve disease (MVD), measure RF in dogs with MVD, and assess the correlation between RF and several clinical and Doppler echocardiographic variables. Prospective study. 6 MVD-affected dogs with no clinical signs and 67 dogs with MVD of differing severity (International Small Animal Cardiac Health Council [ISACHC] classification). The 6 dogs were used to determine the repeatability and reproducibility of the PISA method, and RF was then assessed in 67 dogs of various ISACHC classes. Mitral valve regurgitation was also assessed from the maximum area of regurgitant jet signal-to-left atrium area (ARJ/LAA) ratio determined via color Doppler echocardiographic mapping. Within- and between-day coefficients of variation of RF were 8% and 11%, respectively. Regurgitation fraction was significantly correlated with ISACHC classification and heart murmur grade and was higher in ISACHC class III dogs (mean +/- SD, 72.8 +/- 9.5%) than class II (57.9 +/- 20.1%) or I (40.7 +/- 19.2%) dogs. Regurgitation fraction and left atriumto-aorta ratio, fractional shortening, systolic pulmonary arterial pressure, and ARJ/LAA ratio were significantly correlated. Results suggested that RF is a repeatable and reproducible variable for noninvasive quantitative evaluation of mitral valve regurgitation in awake dogs. Regurgitation fraction also correlated well with disease severity. It appears that this Doppler echocardiographic index may be useful in longitudinal studies of MVD in dogs.

Comparative Adverse Cardiac Effects of Pimobendan and Benazepril Monotherapy in Dogs with Mild Degenerative Mitral Valve Disease: A Prospective, Controlled, Blinded, and Randomized Study

Background: Pimobendan (PIMO) is an inodilator that may have some beneficial effects in canine degenerative mitral valve disease (MVD). However, little information is available about its cardiac effects in dogs without systolic myocardial dysfunction. Hypothesis: Compared to benazepril (BNZ), an angiotensin‐converting enzyme inhibitor, PIMO may worsen valve regurgitation in early canine MVD. Animals: Twelve Beagles with asymptomatic MVD were randomized into 2 groups (n = 6) receiving BNZ or PIMO at dosages of 0.25 mg/kg PO q24h and q12h respectively, for 512 days. Methods: The study followed a blinded, randomized, prospective, and parallel group design. After day 512, the dogs were necropsied, and cardiac histopathology was performed in a blinded manner. Results: A significant treatment effect was observed as soon as day 15 with increased systolic function in the PIMO group by comparison to baseline value as assessed by fractional shortening (P < .0001) and tissue Doppler variables (P= .001). Concurrently, the maximum area and peak velocity of the regurgitant jet signal increased (P < .001), whereas these variables remained stable in the BNZ group. Histologic grades of mitral valve lesions were more severe in the PIMO group than in the BNZ group. Moreover, acute focal hemorrhages, endothelial papillary hyperplasia, and infiltration of chordae tendinae with glycosaminoglycans were observed in the mitral valves of dogs from the PIMO group but not in those of the BNZ group. Conclusions and Clinical Importance: PIMO has adverse cardiac functional and morphologic effects in dogs with asymptomatic MVD. Additional investigation in dogs with symptomatic MVD is now warranted.

Cerebral hemodynamics and oxygenation after serial CSF drainage in infants with PHVD

The aim of our study was to assess consecutive changes in cerebral oxygenation and hemodynamics after serial cerebrospinal fluid (CSF) drainage from a subcutaneous ventricular catheter reservoir (SVCR) in infants with PHVD. Infants with PHVD were studied during CSF drainage from a SVCR on the day of SVCR placement, half a week and one week after SVCR placement. Changes in cHbD and CBV were assessed using near infrared spectrophotometry. Time averaged peak flow velocity (TAPFV), end diastolic flow velocity (EDFV), peak systolic flow velocity (PSFV) and pulsatility index (PI) were measured before (baseline) and after CSF drainage using Doppler ultrasound. Longitudinal data analysis was performed using linear mixed models. Seven patients (GA 26.7–40.4 weeks, BW 800–4575 g) were studied. CSF drainage resulted in a statistically significant increase in CBV during each measurement. The change in CBV was maximal on the day of SVCR placement. A significant increase in cHbD and EDFV, and decrease in PI was observed after CSF drainage only on the day of SVCR placement. Baseline values of all Doppler variables improved consecutively after serial CSF removal in the first week after SVCR placement. Frequent CSF drainage results in consecutive improvement of cerebral perfusion and oxygenation in infants with PHVD.

The Effects of Aging and Physical Activity on Doppler Measures of Diastolic Function

Healthy aging results in changes in Doppler measures of diastolic function. It is unclear whether these alterations are a specific manifestation of the aging process or reflect a cardiac adaptation to a more sedentary lifestyle. It was hypothesized that healthy, but sedentary, aging would result in slowing of diastolic filling and myocardial relaxation, whereas lifelong endurance training would prevent such changes. Doppler data were measured in young subjects and sedentary and fit seniors across a broad range of loading conditions. Thirteen sedentary healthy (70+/-4 years) and 12 fit Masters athlete (68+/-3 years) seniors were recruited. Twelve young healthy (32+/-9 years) subjects were used for comparison. Pulmonary capillary wedge pressure and Doppler variables were measured at the 6 loading conditions of baseline (twice), -15 and -30 mm Hg lower body negative pressure, and 2 levels of saline solution infusion. Doppler variables consisted of early and late mitral inflow velocity (E/A) ratio, isovolumetric relaxation time (IVRT), tissue Doppler velocities (TDI Emean), and propagation velocity of mitral inflow. Aging resulted in a decrease in E/A ratio (p<0.001), TDI Emean (p<0.001), and propagation velocity of mitral inflow (p<0.001) and an increase in IVRT (p=0.001). Lifelong endurance training did not completely prevent the changes in E/A ratio (p=0.212), IVRT (p=0.546), or propagation velocity of mitral inflow (p=1.00). Fit seniors were able to achieve E/A ratios of 1.0 during baseline and saline solution infusion. TDI Emean was higher in fit versus sedentary seniors at baseline (p=0.012) and during maximal lower body negative pressure (p=0.036), but not during saline solution infusion (p=0.493). In conclusion, age-associated abnormalities in Doppler measures of myocardial filling and relaxation are only partially minimized by lifelong endurance training and therefore may be more specific to the aging process than secondary to years of deconditioning.

Usefulness of Right Ventricular Tissue Doppler Imaging to Predict Outcome in Left Ventricular Heart Failure Independent of Left Ventricular Diastolic Function

It is unknown whether right ventricular (RV) tissue Doppler (TD) predicts outcome in patients with left ventricular (LV) heart failure (HF) independently of contemporary echocardiographic Doppler variables of LV diastolic function. Comprehensive echocardiographic Doppler examination was performed before discharge in 107 patients hospitalized with LV HF. The primary end point was cardiac death or rehospitalization for HF. Follow-up was complete for 100 of 107 patients a mean of 527 days after hospital discharge. There were no significant differences in baseline clinical variables (mean age 58+/-12 years, 46% women, 77% hypertensive, 48% diabetic, 41% current smokers, and 23% known coronary artery disease) in prediction of the primary end point. Compared with patients without an event, patients with an event had a larger left atrial volume index (42+/-16 vs 33+/-13 ml/m2, p=0.001), lower LV ejection fraction (35+/-19% vs 46+/-22%, p=0.01), higher mitral peak early diastolic flow velocity/TD early diastolic velocity (19+/-7 vs 14+/-7, p=0.001), lower RV fractional area change (39+/-11% vs 43+/-10%, p=0.04), and lower RV TD systolic velocity (8+/-2 vs 10+/-3 cm/s, p=0.005). On Cox proportional hazards multivariate analysis, left atrial volume index (p=0.01), mitral peak early diastolic flow velocity/TD early diastolic velocity (p=0.03), and RV TD systolic velocity (p=0.04) were independent predictors of outcome. Even when contemporary echocardiographic Doppler measures of LV diastolic function are considered, RV TD systolic velocity is an independent predictor of cardiac death or rehospitalization for HF in patients hospitalized with HF and appears to be superior to conventional 2-dimensional parameters of RV function.

Comparative Adverse Cardiac Effects of Pimobendan and Benazepril Monotherapy in Dogs with Mild Degenerative Mitral Valve Disease: A Prospective, Controlled, Blinded, and Randomized Study

Pimobendan (PIMO) is an inodilator that may have some beneficial effects in canine degenerative mitral valve disease (MVD). However, little information is available about its cardiac effects in dogs without systolic myocardial dysfunction. Compared to benazepril (BNZ), an angiotensin-converting enzyme inhibitor, PIMO may worsen valve regurgitation in early canine MVD. Twelve Beagles with asymptomatic MVD were randomized into 2 groups (n = 6) receiving BNZ or PIMO at dosages of 0.25 mg/kg PO q24h and q12h respectively, for 512 days. The study followed a blinded, randomized, prospective, and parallel group design. After day 512, the dogs were necropsied, and cardiac histopathology was performed in a blinded manner. A significant treatment effect was observed as soon as day 15 with increased systolic function in the PIMO group by comparison to baseline value as assessed by fractional shortening (P < .0001) and tissue Doppler variables (P = .001). Concurrently, the maximum area and peak velocity of the regurgitant jet signal increased (P < .001), whereas these variables remained stable in the BNZ group. Histologic grades of mitral valve lesions were more severe in the PIMO group than in the BNZ group. Moreover, acute focal hemorrhages, endothelial papillary hyperplasia, and infiltration of chordae tendinae with glycosaminoglycans were observed in the mitral valves of dogs from the PIMO group but not in those of the BNZ group. PIMO has adverse cardiac functional and morphologic effects in dogs with asymptomatic MVD. Additional investigation in dogs with symptomatic MVD is now warranted.

Improvement of left ventricular diastolic function after alcohol septal ablation for obstructive hypertrophic cardiomyopathy? Yes, of course, but...

Recently, I have read with a great interest a very important paper by Jassal et al. 1 The authors reported their results of non-invasive evaluation of left ventricular (LV) diastolic function in 30 selected patients with a highly symptomatic obstructive hypertrophic cardiomyopathy (HCM) treated by alcohol septal ablation (ASA). The authors concluded that positive changes in Doppler variables are likely to be due to the improvement of LV relaxation following ASA. Similarly, we have shown the improvement of isovolumic relaxation time after ASA and, moreover, the improvement of Tei index which incorporates both systolic and diastolic time intervals for expressing global ventricular performance.2 However, in fact, the observation by Jassal et al . is the first study to …

Análise da função diastólica do ventrículo esquerdo em hipertensos sob variação de condições hemodinâmicas provocadas: estudo comparativo entre o doppler transmitral e tissular

To evaluate the behavior of LV diastolic displacement velocities of basal posterior septum near mitral ring segment obtained by tissue Doppler in relation to mitral flow velocities of hypertensive subjects, submitted to preload increase by left inferior limbs elevation for 5 minutes, and during 1 minute of handgrip (conditions 1 and 2, respectively). Twenty five outpatients (15 men, 52+/-11 years), with arterial hypertension > 3 years, by the transmitral flow Doppler variables: E, A and E/A, and of tissue Doppler: E', A' and E'/A', in basal situation and in conditions 1 and 2. For comparison of results in basal situation with conditions 1 and 2 a paired t test was applied. E(cm/s) varied from 68,88 +/- 11,94 to 75,82 +/- 15,71* and E'(cm/s) varied from 8,22 +/- 2,30 to 8,31 +/- 2,24 in condition 1 (p<0.05). In addition, a comparison of variation percent (%) of Doppler transmitral indices with corresponding tissue Doppler indices variation % showed a significant difference between E and E', with preload increase (p=0.01). Patients with left ventricular adaptation to systemic arterial hypertension showed less modification of the index E' than E, after preload increase maneuver, an evidence that may suggest its more ample utilization in the context of echocardiographic left ventricular diastolic function evaluation.

Antenatal umbilical coiling index and Doppler flow characteristics

To evaluate whether a relationship exists between the antenatal umbilical coiling index (UCI) and umbilical cord Doppler flow characteristics. During the fetal anatomical survey in 200 consecutive pregnant patients at 18-23 weeks' gestation, we recorded umbilical coiling patterns and blood flow characteristics. The antenatal UCI, calculated as a reciprocal value of the distance between a pair of umbilical cord coils, was compared with Doppler parameters including umbilical vein blood flow volume (in mL/min/kg), and mean resistance index (RI) and peak systolic velocity (PSV in cm/s) averaged from both umbilical arteries. A total of 154 patients met the inclusion criteria of singleton pregnancy and having adequate sonographic umbilical cord images, Doppler flow indices, and all demographic, antenatal and labor data. The mean antenatal UCI was 0.40, with 10th and 90th centiles of 0.20 and 0.60, respectively. The mean +/- SD umbilical artery RI and PSV and umbilical vein blood flow volume were 0.74 +/- 0.07, 25.1 +/- 6.4 cm/s, and 264 +/- 106 mL/min/kg, respectively. All Doppler variables correlated significantly with antenatal UCI, with lower RI and higher PSV and umbilical vein blood flow volume values being associated with higher antenatal UCI (P = 0.016, P < 0.001, and P = 0.032, respectively). However, when stratified by antenatal UCI into hyper- (above 90th centile), normo- (10th-90th centile), and hypocoiled (below 10th centile) umbilical cord groups, a significant difference was observed for PSV only (P = 0.016). It appears that umbilical cord coiling modulates noticeably blood flow through the umbilical cord. We speculate that more prominent umbilical coiling (higher antenatal UCI values) has a protective effect on blood flow in terms of decreased arterial resistance and higher blood flow velocities, as well as increased venous blood flow. However, due to lack of significant differences between Doppler characteristics when stratified by antenatal UCI into hypo-, normo-, and hypercoiled groups, the clinical implications of this observation are uncertain.

Differing myocardial response to a single session of hemodialysis in end-stage renal disease with and without type 2 diabetes mellitus and coronary artery disease

BackgroundThough hemodialysis (HD) acutely improves cardiac function, the impact of background diseases like coronary artery disease (CAD) and Type 2 diabetes (DM) in the setting of end-stage renal disease (ESRD) is not known. Tissue velocity echocardiography (TVE) offers a fast choice to follow changes in myocardial function after HD in ESRD with concomitant DM and /or CAD.Methods46 subjects (17 with ESRD, Group 1; 15 with DM, Group 2; 14 with DM+CAD, Group 3) underwent standard and TVE prior to and shortly after HD. Besides standard Doppler variables, regional myocardial systolic and diastolic velocities, as well as systolic strain rate were post processed.ResultsCompared with pre-HD, post-HD body weight (kg) significantly decreased in all the three groups (51 ± 9 vs. 48 ± 8, 62 ± 10 vs.59 ± 10, and 61 ± 9 vs. 58 ± 9 respectively; all p < 0.01). Left ventricular end diastolic dimensions (mm) also decreased post- HD (46 ± 5 vs. 42 ± 7, 53 ± 7 vs. 50 ± 7, 51 ± 7 vs. 47 ± 8 respectively; all p < 0.01). Regional longitudinal peak systolic velocity in septum (cm/s) significantly increased post-HD in Group 1(5.7 ± 1.6 vs. 7.2 ± 2.3; p < 0.001) while remained unchanged in the other two groups. Similar trends were noted in other left ventricular walls. When the myocardial velocities (cm/s) were computed globally, the improvement was seen only in Group 1 (6.3 ± 1.5 vs. 7.9 ± 2.0; p < 0.001). Global early regional diastolic velocity (cm/s) improved in Group 1, remained unchanged in Group 2, while significantly decreased in Group 3(-5.9 ± 1.3 vs. -4.1 ± 1.8; p < 0.01). Global systolic strain rate (1/sec) increased in the first 2 Groups but remained unchanged (-0.87 ± 0.4 vs. -0.94 ± 0.3; p = ns) in Group 3.ConclusionA single HD session improves LV function only in ESRD without coexistent DM and/or CAD. The present data suggest that not only dialysis-dependent changes in loading conditions but also co-existent background diseases determine the myocardial response to HD.

Comparison of Usefulness of Echocardiographic Doppler Variables to Left Ventricular End-Diastolic Pressure in Predicting Future Heart Failure Events

We sought to determine whether the echocardiographic Doppler parameters of left ventricular diastolic dysfunction predict future heart failure (HF) events and, if so, which parameters best predict HF. We also examined whether the predictive ability of echocardiographic Doppler parameters was related to their prediction of left ventricular end-diastolic pressure (LVEDP). We studied patients who underwent cardiac catheterization and echocardiography performed within a 30-day period. The end point was HF, defined as new-onset or recurrent HF diagnosed by a physician and requiring the initiation or modification of treatment of HF. We identified 289 patients (mean age 63.5 +/- 12.6 years) with a mean follow-up of 10.9 +/- 10.2 months. A total of 24 HF events occurred. LVEDP was a significant predictor of HF univariately and independently in multiple regression models after adjustment for ejection fraction. In Cox models adjusted for age, gender, LVEDP, and ejection fraction, only the left atrial volume index and early mitral inflow to early diastolic tissue velocity (E/e') ratio remained predictive of HF. A multiple regression model, including all echocardiographic variables, showed a persistent, although attenuated, relation of early to late mitral inflow velocity (E/A) ratio and E/e' with LVEDP (p = 0.06 and p = 0.002, respectively). The addition of E/e' or the left atrial volume indexed to body surface area, but not E/A, to the clinical history and left ventricular ejection fraction provided incremental prognostic information. A LVEDP of > or =20 mm Hg, E/e' ratio of > or =15, and left atrial volume index of > or =23 ml/m(2) identified those with a higher risk of HF. In conclusion, invasively determined LVEDP is an independent predictor of future HF events. E/e' and the left atrial volume indexed to body surface area are the best independent predictors of future HF and provide prognostic information incremental to the clinical history and left ventricular ejection fraction.

Comparative Cost-Effectiveness of B-Type Natriuretic Peptide and Echocardiography for Predicting Outcome in Patients With Congestive Heart Failure

Two-dimensional echocardiographic and Doppler variables and B-type natriuretic peptide (BNP) can predict outcomes in patients with congestive heart failure (CHF). However, there is a paucity of data on the relative cost-effectiveness of these modalities in predicting outcome. One hundred sixteen patients hospitalized with CHF underwent simultaneous BNP and Doppler echocardiographic examinations once ready for discharge. The ability of these variables to determine the primary end point (cardiac death or rehospitalization for CHF) was determined. The cost-effectiveness ratios (CER) of 2-dimensional variables, Doppler indexes, and BNP were calculated for prediction of the primary end point. Follow-up was completed in 110 of 116 patients at a mean of 527 days after hospital discharge. Fifty-four patients (50%) reached the primary end point (37 rehospitalizations for CHF and 17 cardiac deaths). When added to a history of admission to the hospital in the preceding year for CHF, a comprehensive Doppler echocardiographic study predicted 52 of 54 events, with a CER of 729.10 dollars, whereas BNP predicted 47 of 54 events (CER 49.98 dollars; p < 0.001 for CER comparison). In patients admitted to hospitals with CHF, predischarge BNP is more cost-effective than comprehensive Doppler echocardiographic examination for the prediction of future cardiac death or rehospitalization for CHF.

Human factors as a source of error in peak Doppler velocity measurement

The study was conducted to assess the error and variability that results from human factors in Doppler peak velocity measurement. The positioning of the Doppler sample volume in the vessel, adjustment of the Doppler gain and angle, and choice of waveform display size were investigated. We hypothesized that even experienced vascular technologists in a laboratory accredited by the Intersocietal Commission for Accreditation of Vascular Laboratories make significant errors and have significant variability in the subjective adjustments made during measurements. Problems of patient variability were avoided by having the four technologists measure peak velocities from an in vitro pulsatile flow model with unstenosed and 61% stenosed tubes. To evaluate inaccurate angle and sample volume positioning, a probe holder was used in some of the experiments to fix the Doppler angle at 60 degrees. The effect of Doppler gain was studied at three settings--low, ideal, and saturated gains--that were standardized from the ideal level chosen by consensus amongst the technologists. Two waveform display sizes were also investigated. Peak velocity measurement was assessed by comparison with true peak velocities. For each variable studied, average peak velocities were calculated from the 10 measurements made by each technologist and used to find the percent error from the true value, and the coefficient of variation was used to measure the variability. Doppler angle, sample volume placement, and the Doppler gain were the most significant sources of error and variability. Inaccurate angle and placement increased the variability in measurements from 1% to 2% (range) to 4% to 6% for the straight tube and from 1% to 2% to 3% to 9% for the 61% stenosis. The peak velocity error was increased from 9% to 13% to 7% to 28% for the stenosis. Both measurement error and variability were strongly dependent on the Doppler gain level. At low gain, the error was approximately 10% less than the true value and at saturated gain, 20% greater. The display size only affected measurements from the stenosed tube, increasing the error from 9% to 13% to 15% to 24%. Major factors affecting Doppler peak velocity measurement error and variability were identified. Inaccurate angle and sample volume placement increased the variability. The presence of a stenosis was found to increase the measurement errors. The error was found to depend on the Doppler gain setting, with greater variability at low and saturated gains and on the display size with a stenosis. Doppler ultrasound peak velocity measurements are widely used for the diagnostic assessment of the severity of arterial stenoses. However, it is known that these measurements are often in error. We have identified subjective human factors introduced by the technologist and assessed their contribution to peak velocity measurement error and variability. It is to be hoped that by understanding this, improvements in the machine design and measurement methods can be made that will result in improved measurement accuracy and reproducibility.

Comparison of effects of uncomplicated canine babesiosis and canine normovolaemic anaemia on abdominal splanchnic Doppler characteristics - a preliminary investigation

A preliminary study was conducted to compare uncomplicated canine babesiosis (CB) and experimentally induced normovolaemic anaemia (EA) using Doppler ultrasonography of abdominal splanchnic vessels. Fourteen dogs with uncomplicated CB were investigated together with 11 healthy Beagles during severe EA, moderate EA and the physiological state as a control group. Canine babesiosis was compared with severe EA, moderate EA and the physiological state using Doppler variables of the abdominal aorta, cranial mesenteric artery (CMA), coeliac, left renal and interlobar, and hilar splenic arteries, and the main portal vein. Patterns of haemodynamic changes during CB and EA were broadly similar and were characterised by elevations in velocities and reductions in resistance indices in all vessels except the renal arteries when compared with the physiological state. Aortic and CMA peak systolic velocities and CMA end diastolic and time-averaged mean velocities in CB were significantly lower (P < 0.023) than those in severe EA. Patterns of renal haemodynamic changes during CB and EA were similar. However, the renal patterns differed from those of aortic and gastrointestinal arteries, having elevations in vascular resistance indices, a reduction in end diastolic velocity and unchanged time-averaged mean velocity. The left renal artery resistive index in CB was significantly higher (P < 0.025) than those in EA and the physiological state. Renal interlobar artery resistive and pulsatility indices in CB were significantly higher (P < 0.016) than those of moderate EA and the physiological state. The similar haemodynamic patterns in CB and EA are attributable to anaemia, while significant differences may additionally be attributed to pathophysiological factors peculiar to CB.

Isolated Type 2 Diabetes mellitus Causes Myocardial Dysfunction That Becomes Worse in the Presence of Cardiovascular Diseases: Results of the Myocardial Doppler in Diabetes (MYDID) Study 1

Aims: Patients with type 2 diabetes mellitus (DM) often suffer disproportionately and have a worse outcome when burdened with cardiovascular complications compared with those without DM. A specific heart muscle disease reportedly caused by DM per se may explain this. We sought to investigate whether an echo Doppler diagnosis of such a myocardial disease is clinically relevant in DM with or without coexistent coronary artery disease (CAD) and/or hypertension (HTN). Subjects andMethods: Two hundred subjects (127 males, 73 females, 56 ± 10 years) including controls (n = 23), patients with HTN (n = 20), CAD (n = 35), uncomplicated DM (n = 59), DM+HTN (n = 27), DM+CAD (n = 16) and DM+CAD+HTN (n = 20) underwent tissue Doppler-enhanced dobutamine stress echocardiography. Myocardial function was assessed by measuring left ventricular myocardial peak systolic velocity (PSV) and early diastolic velocity at rest and during peak stress, besides measurements of standard Doppler variables. Results: Average left ventricular PSV at rest was significantly lower in CAD (4.7 ± 1.5) compared with controls (5.7 ± 1.2) and in DM+CAD+HTN (4.6 ± 1.4) compared with DM (5.6 ± 1.3; all p < 0.05). During peak stress, lower PSV persisted in CAD (9.5 ± 3.1) and DM+CAD+HTN (8.1 ± 2.7), while appearing de novo in DM (11.3 ± 2.6) and HTN (11.0 ± 2.3) unlike in the controls (12.5 ± 2.5; all p < 0.001). When pooled together, DM subjects with CAD and/or HTN or both had significantly lower PSV (9.1 ± 2.7) than those without (10.0 ± 2.8; p < 0.001). Early diastolic velocity response was equally lower in both groups compared with the controls. Conclusion: The results suggest that dobutamine stress unmasks myocardial functional disturbances caused by uncomplicated DM. The discrete disturbances become quantitatively more pronounced in the presence of coexistent cardiovascular diseases.

Assessment of risk for the development of pre‐eclampsia by maternal characteristics and uterine artery Doppler

To develop a method for the estimation of patient-specific risk for the development of pre-eclampsia by combining maternal history and uterine artery Doppler. Prospective multicentre observational study. Antenatal clinics in seven hospitals in the UK and three overseas centres. Unselected women with singleton pregnancies attending for routine antenatal care. Doppler studies of the uterine arteries were performed using colour flow mapping and pulsed wave Doppler at 23 weeks of gestation. The mean pulsatility index (PI) of the two uterine arteries was calculated. Doppler and maternal history variables were combined to develop a model for risk assessment. The incidence of pre-eclampsia was used to derive the prior risk for this complication. The posterior risk was derived by multiplying the prior odds with likelihood ratios (LRs) derived from independent risk factors identified from the maternal history, and the LR estimated from the heights of the frequency distributions of mean PI in affected and unaffected pregnancies. Pre-eclampsia. There were 17,480 women recruited to the study, in which 17,319 (99.1%) of these Doppler examination of both uterine arteries were completed, and outcome data were available in 16,806 (97.0%). Pre-eclampsia occurred in 369 (2.20%) cases. Significant independent prediction of pre-eclampsia was provided by mean PI, ethnic origin, body mass index (BMI), parity, cigarette smoking, history of hypertension and family or personal history of pre-eclampsia. Models were derived allowing calculation of patient-specific risk for development of pre-eclampsia. For a false-positive rate of 25%, the detection rate of pre-eclampsia by screening using maternal history was 45.3%, with uterine artery Doppler it was 63.1% and with combined assessment it was 67.5%. Combining risk factors in the mother's history with Doppler of the uterine arteries allows calculation of patient-specific risk for the development of pre-eclampsia.

Study of the Solar Cycle Dependence of Low‐Degreep‐Modes with Michelson Doppler Imager and VIRGO

Studying variations of observational properties of low-degree solar acoustic p-modes (radial, dipole, and quadrupole) with the activity cycle is important for understanding potential effects of the cycle in the deep interior, obtaining more accurate inversions for the sound speed and rotation, and also for estimating prospective investigation of stellar activity by asteroseismology. We have analyzed changes of low-degree p-mode parameters during the current solar cycle (number 23) by using velocity and intensity oscillation data from two instruments on the Solar and Heliospheric Observatory (SOHO): the Michelson Doppler Imager (MDI) and Variability of Solar Irradiance and Gravity Oscillations (VIRGO). We show a clear dependence of mode frequency, line width, frequency splitting, and line asymmetry on the solar cycle. Moreover, we demonstrate that these properties change differently for modes of different frequency, angular degree, and order. The greatest changes are observed for sectorial modes of frequencies higher than 3 mHz, corresponding to the fact that the most significant variations of the solar structure occur in low-latitude regions close to the solar surface.

Abnormalities of Doppler Measures of Diastolic Function in the Healthy Elderly Are Not Related to Alterations of Left Atrial Pressure

Normal healthy aging results in changes in Doppler indexes of diastolic function. One widely accepted explanation for these alterations that is based on animal data is an age-associated impairment of myocardial relaxation resulting from abnormal myocyte calcium handling. However, an alternative theory based on altered left atrial compliance with aging has been proposed in which early left atrial pressure could be low in the aged heart but rise rapidly during atrial diastole, resulting in a higher late atrial pressure and thus a normal mean pressure. We sought to explore this issue directly by performing a detailed analysis of the pulmonary capillary wedge pressure waveform obtained by right-heart catheterization during 5 different loading conditions. Twelve healthy elderly sedentary subjects (mean age, 69.8+/-3 years) were recruited for the seniors group. An additional 12 young sedentary subjects (mean age, 35+/-8 years) made up the young group. All subjects were rigorously screened for comorbidities. All subjects underwent transthoracic echocardiography to determine Doppler variables of early and late transmitral filling (E and A velocities) and isovolumetric relaxation time. Each subject also underwent pulmonary artery catheterization with measurement of pulmonary capillary wedge pressure waveform during 5 different loading conditions: baseline, lower-body negative pressures of -15 and -30 mm Hg, and rapid saline infusions of 10 to 15 and 20 to 30 mL/kg. Pressure was measured at 6 points of the waveform: point 1, peak of the atrial contraction (a wave); point 2, the left atrial pressure during the start of ventricular systole; point 3, peak of atrial filling (v wave); point 4, earliest left atrial pressure during ventricular filling; and the line between points 5 and 6, pressure during diastasis. Aging resulted in a decrease in the E/A ratio (P<0.001) and a prolongation of the isovolumetric relaxation time (P<0.001) as assessed by echocardiography, but there was no effect of age on pulmonary capillary wedge pressure at any point throughout the cardiac cycle (P=0.290). Specifically, at no measured point at any level of cardiac filling volume was the pulmonary capillary wedge pressure of the seniors lower than that of the young subjects. We conclude that the age-related echocardiographic change of decreasing E/A ratio is not the result of a lowering of early diastolic left atrial pressure.

Spectral Doppler Index Mapping of the Umbilicoplacental Circulation and Pregnancy Outcome

Objective: To determine the value of Doppler measurements obtained by a new multigate Doppler modality, the spectral Doppler index mapping (SDIM) technique, to predict adverse outcome among pregnant women with normal conventional umbilical artery (UA) Doppler indices. Design: A cross-sectional prospective cohort study. Subjects: 183 women with well-dated singleton pregnancies who underwent prenatal ultrasound examination between 18 and 40 weeks of gestation were included in the study. At the time of the initial Doppler examination, all patients had normal UA and uterine artery Doppler indices, size appropriate for gestational age, no evidence of fetal anomalies or fetal distress. Methods: SDIM data included the distribution curves of the pulsatility indices (PI) as well as the mean of the PI detected in the placenta and in the umbilical cord. The mean PI values were also calculated using conventional spectral Doppler sonography. Logistic regression analysis was used to control for gestational age while assessing various Doppler variables in predicting outcome. Results: Adverse outcomes occurred in 26.6% of the pregnancies. In pregnancies with adverse outcome, the umbilicoplacental PI gradient was significantly lower (0.10 vs. 0.28, p < 0.003), the maximum intraplacental PI value was higher (1.28 vs. 1.16, p = 0.031), and there was a greater proportion with skewed UA distribution curves. Using forward stepwise logistic regression to compare the predictive value of the conventional Doppler ultrasound with SDIM, we found that the most accurate predictors of adverse outcome were the maximum intraplacental PI value (p < 0.028), skewed distributions (p = 0.002) and the gradient between the umbilical and intraplacental PI distributions (p = 0.006). Conclusions: Our results suggest that the SDIM system may enhance the ability of Doppler technology to predict obstetrical outcomes in patients with normal UA Doppler indices.

Différentes applications cliniques des signaux microemboliques détectés par Doppler transcrânien et leur contribution potentielle dans la prise de décision thérapeutique

Given the fact that most strokes are due to thromboembolism, transcranial Doppler (TCD) detection of cerebral microemboli offers the opportunity to study the pathogenesis of cerebral ischaemia and may allow identificationof patients who are at highest risk of stroke and in most urgent need of treatment. Various studies have shown that emboli detection may be very useful in different clinical situations. Studies focusing on the acute phase of stroke demonstrated that the overall frequency of microembolic signals (MES) varies very widely. Differences in the intervals from stroke onset and TCD recordings, in the duration of recordings, in the criteria used to define MES and the small size of the study groups may explain these variations. MES are mostly found among patients with potential arterial or cardiac embolic sources and are very rarely encountered among patients with lacunar stroke. These findings favour the assumption that MES correspond to brain embolism and also that embolisation does not constitute the predominant mechanism of lacunar stroke. The presence of MES detected during the acute phase of stroke also predicts increased risk of further events. The prevalence of MES has also been extensively studied in the setting of carotid artery disease. Soon after the observation of the presence of MES during endarterectomy, similar signals occurring spontaneously were recognised in patients with symptomatic carotid artery disease. Furthermore, since MES almost completely disappear after carotid endarterectomy, it was assumed that the atherosclerotic plaque in the carotid artery was the source of MES. Overall the frequency of MES is more important among symptomatic than asymptomatic patients. However, most of the studies report a higher frequency of MES in the presence of higher degrees of stenosis in the ipsilateral internal carotid artery. In fact, the more severe the narrowing, the more MES are detected. The beneficial effects of carotid endarterectomy in symptomatic and asymptomatic patients with high-grade carotid artery stenosis have been demonstrated in various studies. However, the risks of carotid surgery are not negligible and overall approximately 3 to 5% of the patients undergoing surgery may suffer a stroke or death during or just after surgery. The safety of the surgical procedure is therefore of considerable importance and it is therefore essential to improve the prevention of neurological complications. Several studies have shown that TCD monitoring of embolism and haemodynamic changes in the middle cerebral artery may in fact provide important information to the surgeon instantaneously during endarterectomy. The four following transcranial Doppler variables are independently associated with occurrence of stroke during or after the procedure: microemboli during dissection and wound closure; >90% decrease in MCA peak systolic velocity during cross-clamping and >100% increase of the pulsatility index at clamp release. Various studies also demonstrate that MES are detected in almost 70% of the cases during the first hours postoperatively and are strong predictors of ischaemic neurological deficits in the territory of the insonated middle cerebral artery. Furthermore, emboli detection during coronary bypass surgery has increasingly been recognised during these last years as potential markers for the occurrence of cognitive impairment, despite changes performed in the surgical technique, such as the introduction of arterial-line filters and membrane oxygenators. Finally, the contribution of MES detection to the therapeutical decision has been determined in various clinical situations. Rapid disappearance of MES after administration of a certain number of medications such as antiplatelets, GP IIb/IIIa antagonists receptors, S-nitrosoglutathione, a nitric oxyde donor or dextran 40, suggests that MES constitute potential markers allowing assessment of treatment efficacy and thereby reducing the risk of further cereb