Ventricular Outflow Tract Velocity-time Integral Research Articles

Transthoracic echocardiography to quantify pulmonary vascular resistances in patients with systemic sclerosis

One of the major causes of systemic sclerosis (SSc)-related death is pulmonary hypertension (PH), which develops in 12–15% of patients with SSc and accounts for 30–40% of deaths. Cardiac involvement is common in SSc and has been reported to range from 23 to 32%. Both pathophysiological processes can lead to PH. Consequently, monitoring of pulmonary arterial resistances (PVR) is essential in patients with SSc. Tricuspid regurgitation velocity (TRV) to right ventricular outflow tract time-velocity integral (VTI RVOT ) ratio by Doppler has been reported as a good tool to quantify PVR. Explore the accuracy of TRV/VTI RVOT ratio by Doppler to quantify PVR in patients with SSc. Thirty-five consecutive patients with SSc referred for right heart catheterization (RHC) were retrospectively included. Doppler measures were compared to RHC measures. There were 20 (57%) female. The mean age was 65 ± 12 years. Mean and systolic pulmonary arterial pressures were 31 ± 8 and 53 ± 15 mmHg. There was a good correlation between TRV/VTI RVOT ratio assessed by Doppler and PVR measured by RHC ( R = 0.743, P < 0.001). The equation generated by this analysis was: PVR by Doppler = 11.3 × (TRV/TVIRVOT) + 1.7. A cutoff value of 0.21 for TRV/TVIRVOT ratio provided the best sensitivity (86%) and specificity (86%) to determine PVR > 3 Wood units ( Fig. 1 ). Our study suggests that transthoracic echocardiography using Doppler could be an interesting and non-invasive tool to estimate PVR in patients with SSc.

Doppler Parameters Derived from Transthoracic Echocardiography Accurately Detect Bioprosthetic Mitral Valve Dysfunction

Detecting bioprosthetic mitral valve dysfunction on transthoracic echocardiography can be challenging because of acoustic shadowing of regurgitant jets and a wide normal range of transvalvular gradients. Several studies in mechanical mitral valves have demonstrated the utility of the transthoracically derived parametersE (peak early mitral inflow velocity), pressure half-time, and the ratio of mitral inflow velocity-time integral(VTIMV) to left ventricular outflow tract velocity-time integral (VTILVOT) in detecting significant prostheticdysfunction. Uncertainty exists as to their applicability and appropriate cutoff levels in bioprosthetic valves. This study was designed to establish the accuracy and appropriate normal limits of routinely collected transthoracic Doppler parameters when used to assess bioprosthetic mitral valve function. A total of 135 clinically stable patients with bioprosthetic mitral valves who had undergone both transthoracic and transesophageal echocardiography within a 6-month period were retrospectively identified from the past 11years of the echocardiography database. Transthoracic findings were labeled as normal (n=81), regurgitant (n=44), or stenotic (n=10) according to the patient's transesophageal echocardiographic findings. Univariate and multivariate analyses were performed to identify Doppler parameters that detected dysfunction; then receiver operating characteristic curves were created to establish appropriate normal cutoff levels. The VTIMV/VTILVOT ratio was the most accurate Doppler parameter at detecting valvular dysfunction, with a ratio of >2.5 providing sensitivity of 100% and specificity of 95%. E>1.9m/sec was slightly less accurate (93% sensitivity, 72% specificity), while a pressure half-time of >170msec had both 100% specificity and sensitivity for detecting significant bioprosthetic mitral valve stenosis, (although it did not differentiate between regurgitant and normal). This study demonstrates that Doppler parameters derived from transthoracic echocardiography can accurately detect bioprosthetic mitral valve dysfunction. These parameters, particularly a VTIMV/VTILVOT ratio of >2.5, are a sensitive way of selecting patients to undergo more invasive examination with transesophageal echocardiography.

28 - Transthoracic echocardiography to quantify pulmonary vascular resistance in patients with systemic sclerosis

Background One of the major causes of systemic sclerosis (SSc)-related death is pulmonary hypertension (PH), which develops in 12–15% of patients with SSc and accounts for 30–40% of deaths. Cardiac involvement is common in SSc and has been reported to range from 23 to 32%. Both pathophysiological processes can lead to PH. Consequently, monitoring of pulmonary arterial resistances (PVR) is essential in patients with SSc. Tricuspid regurgitation velocity (TRV) to right ventricular outflow tract time-velocity integral (VTIRVOT) ratio by Doppler has been reported as a good tool to quantify PVR. Aim Explore the accuracy of TRV/VTIRVOT ratio by Doppler to quantify PVR in patients with SSc. Methods and results Thirty-five consecutive patients with SSc referred for right heart catheterization (RHC) were retrospectively included. Doppler measures were compared to RHC measures. There were 20 (57%) female. The mean age was 65 ± 12 years. Mean and systolic pulmonary arterial pressures were 31 ± 8 and 53 ± 15 mmHg. There was a good correlation between TRV/VTIRVOT ratio assessed by Doppler and PVR measured by RHC (R = 0.743, P 3 Wood units ( Fig. 1 ). Conclusion Our study suggests that transthoracic echocardiography using Doppler could be an interesting and non-invasive tool to estimate PVR in patients with SSc.

Field Ultrasound Evaluation of Central Volume Status and Acute Mountain Sickness

To investigate whether ultrasonography can be used for field volume status assessment and to determine whether a detectable difference in intravascular volume exists in individuals with acute mountain sickness (AMS) compared with those without. Study was performed at the Himalayan Rescue Association Clinic in Manang, Nepal, located on the Annapurna trekking circuit at an altitude of 3519 m (11545 feet). A convenience sample was taken from individuals trekking over 5 to 8 days from 760 m (2490 feet) to 3519 m (11,545 feet), comparing asymptomatic trekkers vs those who experienced AMS. Subjects were evaluated for AMS based on the Lake Louise AMS Questionnaire (LLS ≥ 3 indicates AMS). After medical screening examination, both groups (control, n = 51; AMS, n = 18) underwent ultrasonography to obtain measurements of inferior vena cava collapsibility index (IVC CI) and left ventricular outflow tract velocity-time integral (LVOT VTI) before and after a passive leg raise (PLR) maneuver. There was no statistically significant difference between groups regarding change in heart rate before and after PLR, or IVC CI; however, there was a statistically significant greater increase in LVOT VTI after PLR maneuver in control group subjects compared with those with AMS (18.96% control vs 11.71% AMS; P < .01). Ultrasonography is a useful tool in the assessment of intravascular volume at altitude. In this sample, we found ultrasonographic evidence that subjects with AMS have a higher intravascular volume than asymptomatic individuals. These data support the hypothesis that individuals with AMS have decreased altitude-related diuresis compared with asymptomatic individuals.

A Simple Echocardiographic Method to Estimate Pulmonary Vascular Resistance

Pulmonary hypertension includes heterogeneous diagnoses with distinct hemodynamic pathophysiologic features. Identifying elevated pulmonary vascular resistance (PVR) is critical for appropriate treatment. We reviewed data from patients seen at referral pulmonary hypertension clinics who had undergone echocardiography and right-side cardiac catheterization within 1 year. We derived equations to estimate PVR using the ratio of estimated pulmonary artery (PA) systolic pressure (PASPDoppler) to right ventricular outflow tract velocity time integral (VTI). We validated these equations in a separate sample and compared them with a published model based on the ratio of the transtricuspid flow velocity to right ventricular outflow tract VTI (model 1, Abbas et al 2003). The derived models were as follows: PVR = 1.2 × (PASP/right ventricular outflow tract VTI) (model 2) and PVR = (PASP/right ventricular outflow tract VTI) + 3 if notch present (model 3). The cohort included 217 patients with mean PA pressure of 45.3 ± 11.9 mm Hg, PVR of 7.3 ± 5.0 WU, and PA wedge pressure of 14.8 ± 8.1 mm Hg. Just >1/3 had a PA wedge pressure >15 mm Hg (35.5%) and 82.0% had PVR >3 WU. Model 1 systematically underestimated catheterization estimated PVR, especially for those with high PVR. The derived models demonstrated no systematic bias. Model 3 correlated best with PVR (r = 0.80 vs r = 0.73 and r = 0.77 for models 1 and 2, respectively). Model 3 had superior discriminatory power for PVR >3 WU (area under the curve 0.946) and PVR >5 WU (area under the curve 0.924), although all models discriminated well. Model 3-estimated PVR >3 was 98.3% sensitive and 61.1% specific for PVR >3 WU (positive predictive value 93%; negative predictive value 88%). In conclusion, we present an equation to estimate the PVR, using the ratio of PASPDoppler to right ventricular outflow tract VTI and a constant designating presence of right ventricular outflow tract VTI midsystolic notching, which provides superior agreement with catheterization estimates of PVR across a wide range of values.

Left ventricular function in pulmonary hypertension

To elucidate left ventricular function in pulmonary hypertension, we measured parameters of left ventricular as well as right ventricular function by echocardiography in 11 patients with pulmonary hypertension (idiopathic pulmonary artery hypertension in 4, chronic thromboembolic pulmonary hypertension in 5, and other pulmonary hypertension in 2). The percent change in these parameters 6 months after treatment with pulmonary artery vasodilators (beraprost in 8 and sildenafil in 3) was assessed. There was a correlation between the relative change in right ventricular systolic pressure (RVSP) and the relative changes in left ventricular outflow tract velocity-time integral (r = -0.730, P = 0.011) and mitral valve velocity-time integral (r = -0.621, P = 0.041). However, there was no correlation between the relative change in RVSP and the relative changes in left ventricular ejection fraction, left ventricular diastolic dimension, and systolic blood pressure. The relative change in RVSP was also correlated with the relative change in early diastolic myocardial velocity at the medial mitral annulus (r = -0.675, P = 0.023). Reduction of RVSP by pulmonary artery vasodilators might increase left ventricular preload, leading to an increase in stroke volume. Right ventricular load reduction might improve left ventricular diastolic function in patients with pulmonary hypertension, possibly through altered interventricular septal performance.

Choosing between velocity-time-integral ratio and peak velocity ratio for calculation of the dimensionless index (or aortic valve area) in serial follow-up of aortic stenosis

BackgroundIt remains unclear which echocardiographic measure is most suitable for serial measurement in real-world aortic stenosis (AS) follow-up. We determine whether the dimensionless index (DI) between aortic valve and left ventricular outflow tract velocities is measured more consistently using velocity-time-integral (VTI) or peak velocities (Vpeak) in real life. MethodsSerial echocardiograms acquired within 6months in subjects with AS were analysed with blinding, to compare the variability over time of DI calculated using Vpeak, with that of DI calculated using VTI. ResultsPaired echocardiograms, acquired on average 72days apart, were analysed from 70 patients with a range of severities of AS (59% severe). DI, calculated using either Vpeak or VTI, did not significantly change over this short time. Coefficient of variation was significantly better when DI was calculated using Vpeak than VTI (12.6 versus 25.4%, p<0.0001). The variabilities of mean and peak trans-aortic valve 4v2 and left ventricular outflow tract VTI were no better: 26.9%, 19.1% and 22.1% respectively. ConclusionsSerially-followed variables require minimal noise to maximise detection of genuine change. For AS surveillance, calculating DI – or effective orifice area – from the ratio of Vpeak rather than VTIs would reduce 95% confidence intervals from ±51% to a still-disappointing ±25%. Guidelines recommend noisy surveillance measures, causing conscientious echocardiographers to ‘peek’ at previous values, and impairing clinicians' faith in echocardiographically-observed changes when making clinical decisions. For us in echocardiography to improve our ability to contribute to AS follow-up requires us to first acknowledge and discuss this honestly.

Range in Pulmonary Artery Systolic Pressure Among Highly Trained Athletes

Although the physiologic range of pulmonary artery systolic pressure (PASP) has been reported, data on how it is manifested in athletes are limited. The aim of the present study was to explore the full spectrum of PASP and the long-term training impact in a large population of highly trained athletes. Six hundred fifteen consecutive athletes (370 endurance-trained athletes [ATEs] vs 245 strength-trained athletes [ATSs]; 28.4 ± 10.1 years old) and 230 healthy control subjects (27.5 ± 11.3 years old) underwent transthoracic echocardiography. PASP was estimated by measuring maximal tricuspid regurgitant jet velocity (TRV) with the modified Bernoulli equation. The ratio of TRV to right ventricular outflow tract time-velocity integral (TRV/RVOTTVI) was obtained as a correlate of pulmonary vascular resistance (PVR). Left ventricular (LV) mass index and ejection fraction did not differ significantly between the two groups of athletes. Conversely, ATSs showed an increased sum of wall thickness and relative wall thickness, whereas LV end-diastolic diameter, LV stroke volume, peak TRV, and PASP were significantly higher in ATEs. The ratio between transmitral E wave and tissue Doppler e' wave was not different among the three groups. The ratio TRV/RVOTTVI was ≤ 0.2 (ie, normal PVR) in all subjects. A TRV value > 2.5 m/s was observed in 76 athletes (12.3%). By multivariable analysis, age (P < .01), type and duration of training (P < .01), and LV stroke volume (P < .001) were the only independent predictors of PASP in athletes. This study delineates the full range of resting TRV and derived PASP in highly trained athletes. The upper physiologic limit of PASP in endurance athletes may reach 40 mm Hg, in line with the greater increase in stroke volume. This should be considered a "physiologic phenomenon" when evaluating athletes for sports eligibility.

Comparison of Hemodynamic versus Dyssynchrony Assessment for Interventricular Delay Optimization with Echocardiography in Cardiac Resynchronization Therapy

Best practice for cardiac resynchronization therapy (CRT) device optimization is not established. This study compared Tissue Doppler Imaging (TDI) to study left ventricular (LV) synchrony and left ventricular outflow tract velocity-time integral (LVOT VTI) to assess hemodynamic performance. LVOT VTI and LV synchrony were tested in 50 patients at three interventricular (VV) delays (LV preactivation at -30 ms, simultaneous biventricular pacing, and right ventricular preactivation at +30 ms), selecting the highest VTI and the greatest degree of superposition of the displacement curves, respectively, as the optimum VV delay. In 39 patients (81%), both techniques agreed (Kappa = 0.65, p < 0.0001) on the optimum VV delay. LV preactivation (VV - 30) was the interval most frequently chosen. Both TDI and LVOT VTI are useful CRT programming methods for VV optimization. The best hemodynamic response correlates with the best synchrony. In most patients, the optimum VV interval is LV preactivation.

Can Echocardiographic Evaluation of Cardiopulmonary Hemodynamics Decrease Right Heart Catheterizations in End-Stage Heart Failure Patients Awaiting Transplantation?

Candidacy for heart transplantation is influenced by the severity of pulmonary hypertension. In this study, invasive hemodynamics from right-sided cardiac catheterization were compared with values obtained by validated equations from Doppler 2-dimensional transthoracic echocardiography. This prospective study was conducted in 40 patients with end-stage heart failure evaluated for heart transplantation or ventricular assist device implantation. Transthoracic echocardiography and right-sided cardiac catheterization were performed within 4 hours. From continuous-wave Doppler of the tricuspid regurgitation jet, pulmonary artery systolic pressure was calculated as the peak gradient across the tricuspid valve plus right atrial pressure estimated from inferior vena cava filling. Mean pulmonary artery pressure was calculated as (0.61 × pulmonary artery systolic pressure) + 2. Pulmonary vascular resistance (PVR) was calculated as (tricuspid regurgitation velocity/right ventricular outflow tract time-velocity integral × 10) + 0.16. Pulmonary capillary wedge pressure was calculated as 1.91 + (1.24 × E/E'). Pearson's correlation and Bland-Altman analysis of mean differences between echocardiographic and right-sided cardiac catheterization measurements were statistically significant for all hemodynamic parameters (pulmonary artery systolic pressure: r = 0.82, p < 0.05, mean difference 3.1 mm Hg, 95% confidence interval [CI] -0.2 to 6.3; mean pulmonary artery pressure: r = 0.80, p < 0.05, mean difference 2.5 mm Hg, 95% CI 0.3 to 4.6; PVR: r = 0.52, p < 0.05, mean difference 0.8 Wood units, 95% CI 0.3 to 1.4; pulmonary capillary wedge pressure: r = 0.65, p < 0.05, mean difference 2.2 mm Hg, 95% CI 0.1 to 4.3). Compared with right-sided cardiac catheterization, PVR by Doppler echocardiography identified all patients with PVR > 4 Wood units (n = 4), 73% of patients with PVR <2 Wood units (n = 8), and 52% of patients with PVR from 2 to 4 Wood units (n = 10). In conclusion, echocardiographic estimation of cardiopulmonary hemodynamics is reliable in patients with end-stage cardiomyopathy. The noninvasive assessment of hemodynamics by echocardiography may be able to decrease the number of serial right-sided cardiac catheterizations in selected patients awaiting heart transplantation. However, in patients with borderline PVR, right-sided cardiac catheterization is indicated to assess eligibility for transplantation.

Echocardiographic assessment of pulmonary vascular resistance in pulmonary arterial hypertension

BackgroundEchocardiographic ratio of peak tricuspid regurgitant velocity to the right ventricular outflow tract time-velocity integral (TRV/TVI rvot) was presented as a reliable non-invasive method of estimating pulmonary vascular resistance (PVR). Studies using this technique in patients with moderate to high PVR are scarce. Left ventricular outflow tract time-velocity integral (TVI lvot) can be easier to measure than TVI rvot, especially in patients with severe pulmonary hypertension (PH) with significant anatomical modifications of the right structures.AimsWe wanted to determine whether the TRV/TVI rvot and TRV/TVI lvot ratios would form a reliable non-invasive tool to estimate PVR in a cohort of patients with moderate to severe pulmonary vascular disease.MethodsDoppler echocardiographic examination and right heart catheterisation were performed in 37 patients. Invasive PVR was compared with TRV/TVI rvot and TRV/TVI lvot ratios using regression analysis. Two equations were modelled and the results compared with invasive measurements using the Bland-Altman analysis. Using receiver-operating characteristics curve analysis, a cut-off value for the two ratios was generated.ResultsCorrelation coefficients between invasive PVR and TRV/TVI rvot then TRV/TVI lvot were respectively 0.76 and 0.74. Two new equations were found but the Bland-Altman analysis showed wide standard deviations (respectively 3.8 and 3.9 Wood units). A TRV/TVI rvot then TRV/TVI lvot ratio cut-off value of 0.14 had a sensitivity of 93% and a specificity of 57% for the first and a sensitivity of 87% and a specificity of 57% for the second to determine PVR > 2 Wood units.ConclusionEchocardiography is useful for the screening of patients with pulmonary hypertension and PVR > 2 WU. It remains disappointing for accurate assessment of high PVR. TVI lvot may be an alternative to TVI rvot for patients for whom accurate TVI rvot measurement is not possible.

Comprehensive Echocardiographic Assessment of Normal Mitral Medtronic Hancock II, Medtronic Mosaic, and Carpentier-Edwards Perimount Bioprostheses Early after Implantation

Normal Doppler-derived hemodynamic data for mitral valve bioprostheses are limited. To establish parameters for identifying normal function for each of the 3 types of bioprostheses examined, we conducted a comprehensive, retrospective, two-dimensional, and Doppler echocardiographic assessment of 179 patients who underwent implantation of the Medtronic Hancock II or the Medtronic Mosaic (Medtronic, Inc, Minneapolis, MN) porcine mitral valve bioprosthesis or the Carpentier-Edwards Perimount (Edwards Lifesciences LLC, Irvine, CA) bovine pericardial mitral valve bioprosthesis. All bioprostheses were normal by clinical examination, intraoperative transesophageal echocardiography, and postoperative transthoracic echocardiography. Regardless of valve type and body surface area, the pressure half-time was < 124 ms in all patients. Mean gradient < 9.5 mm Hg, mitral E velocity < 2.6 m/s, mitral valve prosthesis time-velocity integral < 69 cm, and ratio of the mitral valve prosthesis time-velocity integral to the left ventricular outflow tract time-velocity integral < 3.4 were recorded in nearly all patients. These cutoff values (mean + 2 standard deviation) are specific, but not sensitive, for identifying mitral valve prosthesis dysfunction. Prostheses with hemodynamic values that are higher than these cutoff values are likely dysfunctional, but in select cases, mitral valve prosthesis dysfunction may be present even when hemodynamic values are lower than these thresholds.

A prospective comparison of echocardiography and device algorithms for atrioventricular and interventricular interval optimization in cardiac resynchronization therapy

Echocardiographic optimization of atrioventricular (AV) and interventricular (VV) intervals in cardiac resynchronization therapy (CRT) is costly, time-consuming, and requires skill and expertise so is usually undertaken only in 'non-responder' patients. An algorithm in St Jude Medical CRT devices (QuickOpt) claims to optimize these settings automatically. The aim of this study was to compare the two optimization techniques. Optimization of AV and VV intervals was performed a month after CRT device implantation in 26 patients with heart failure, first by echocardiography then by QuickOpt. The left ventricular outflow tract (LVOT) velocity-time integral (VTI) was measured after optimization by each method. Agreement between the optimization methods was assessed by the Bland-Altman analysis and correlation by Pearson's correlation coefficient. There was good correlation between the LVOT VTI following optimization by both methods (R2 = 0.77, P < 0.001). However, agreement between the two methods was poor, with 15 of 26 and 10 of 26 patients having a >20 ms difference in the optimal AV and VV interval values, respectively. Left ventricular outflow tract VTI was significantly better (22 of 26 patients; P < 0.001) in patients optimized by echocardiography than by QuickOpt. There is a poor agreement in optimal AV and VV intervals determined by echocardiography and QuickOpt, with echocardiographic optimization giving a superior haemodynamic outcome.

A critical comparison of echocardiographic measurements used for optimizing cardiac resynchronization therapy: stroke distance is best

Dyssynchrony assessment in cardiac resynchronization therapy (CRT) is controversial, and there are no standard protocols for optimizing treatment. We studied the feasibility and reproducibility of several echocardiographic measures to optimize CRT pacemaker settings. We also assessed the utility of 'stroke distance' [left ventricular outflow tract velocity-time integral (LVOT VTI)] in performing this function. Thirty patients underwent the following functional assessments; 6 min walk test distance, peak VO(2) consumption on cardiopulmonary exercise testing (VO(2) peak), quality-of-life scoring, and echocardiography; before and at 3 and 6 months after implantation of the CRT device. At 3 months, patients received LVOT VTI-guided optimization of interventricular (VV) and atrioventricular (AV) delays. The feasibility and reproducibility of each optimization measurement was statistically analysed, and the functional benefits of optimization examined. Left ventricular outflow tract VTI, interventricular mechanical delay (IVMD), and tissue Doppler lateral-septal delay showed good feasibility (>90%), whereas LVOT VTI, IVMD, and the 12-segment tissue Doppler dyssynchrony index showed good reproducibility (coefficient of variation <20%). The most feasible and reproducible measure was LVOT VTI. Our optimization protocol necessitated alteration of AV and/or VV delays in 60% of patients at 3 months and was associated with a 50% improvement in functional responder status between 3 and 6 months. Left ventricular outflow tract VTI provides us with a single, direct measure of global LV function which is robust, and easily applicable in routine clinical practice, and which is effective at improving response to CRT.

Development of an Echocardiographic Risk‐Stratification Index to Predict Heart Failure in Patients With Stable Coronary Artery Disease: The Heart and Soul Study

Abstract. Objectives. We sought to determine which transthoracic echocardiographic (TTE) measurements most strongly predict heart failure (HF) and to develop an index for risk stratification in outpatients with coronary artery disease (CAD). Background. Many TTE measurements have been shown to be predictive of HF, and they might be useful if aggregated into a risk‐prediction index. Methods. We performed TTE in 1024 outpatients with stable CAD enrolled in the Heart and Soul study and followed them for 4.4 years. With Cox proportional hazard models, we evaluated the association of 15 TTE measurements with subsequent HF hospital stay. Those measurements that independently predicted HF were combined into an index. Variables were defined as normal or abnormal on the basis of dichotomous cutoffs determined from the American Society of Echocardiography. Abnormal variables in each measurement were assigned points on the basis of strength of association with HF. Results. Of the 15 variables, 5 measurements were independent predictors of HF: left ventricular mass index (LVMI), left atrial volume index (LAVI), mitral regurgitation (MR), left ventricular outflow tract velocity‐time integral (VTILVOT), and diastolic dysfunction (DD). In multivariate analysis, each of the 5 measurements independently predicted HF: LVMI &gt;90 g/m2 (hazard ratio [HR], 4.1; 95% confidence interval [CI], 2.3–7.2; P&lt;.0001); pseudo‐normal or restrictive DD (HR, 2.9; 95% CI, 1.8–4.5; P&lt;.0001); VTILVOT &lt;22 mm (HR, 2.2; 95% CI, 1.4–3.5; P=.0004); mild, moderate, or severe MR (HR, 1.8; 95% CI, 1.2–2.8; P=.009); and LAVI &gt;29 mL/m2 (HR, 1.6; 95% CI, 1.0–2.5; P&lt;.06). Combining these measurements, the Heart Failure Index ranged from 0 to 8, representing risk as follows: 3 points for LVMI, 2 points for DD, and 1 point for VTILVOT, MR, and LAVI. Among participants with 0 to 2 points: 4% had HF hospital stays (reference); 3 or 4 points: 10% (HR, 2.4; 95% CI, 1.3–4.4; P=.003); 5 or 6 points: 24% (HR, 6.2; 95% CI, 3.6–10.6; P&lt;.0001); 7 or 8 points: 48% (HR, 13.7; 95% CI, 7.2–25.9; P&lt;.0001). Conclusions. We identified 5 TTE measurements that independently predict HF in patients with stable CAD and combined them as an index that might be useful for risk stratification and serial observations.—Stevens SM, Farzaneh‐Far R, Na B, et al. Development of an echocardiographic risk‐stratification index to predict heart failure in patients with stable coronary artery disease: the Heart and Soul study. JACC Cardiovasc Imaging. 2009;2(1):21–23.

A Novel Non-Invasive Method of Estimating Pulmonary Vascular Resistance in Patients With Pulmonary Arterial Hypertension

The assessment of pulmonary vascular resistance (PVR) plays an important role in the diagnosis and management of pulmonary arterial hypertension (PAH). The main objective of this study was to determine whether the noninvasive index of systolic pulmonary arterial pressure (SPAP) to heart rate (HR) times the right ventricular outflow tract time-velocity integral (TVI(RVOT)) (SPAP/[HR x TVI(RVOT)]) provides clinically useful estimations of PVR in PAH. Doppler echocardiography and right-heart catheterization were performed in 51 consecutive patients with established PAH. The ratio of SPAP/(HR x TVI(RVOT)) was then correlated with invasive indexed PVR (PVRI) using regression and Bland-Altman analysis. Using receiver operating characteristic curve analysis, a cutoff value for the Doppler equation was generated to identify patients with PVRI > or = 15 Wood units (WU)/m2. The mean pulmonary arterial pressure was 52 +/- 15 mm Hg, the mean cardiac index was 2.2 +/- 0.6 L/min/m2, and the mean PVRI was 20.5 +/- 9.6 WU/m2. The ratio of SPAP/(HR x TVI(RVOT)) correlated very well with invasive PVRI measurements (r = 0.860; 95% confidence interval, 0.759-0.920). A cutoff value of 0.076 provided well-balanced sensitivity (86%) and specificity (82%) to determine PVRI > 15 WU/m2. A cutoff value of 0.057 increased sensitivity to 97% and decreased specificity to 65%. The novel index of SPAP/(HR x TVI(RVOT)) provides useful estimations of PVRI in patients with PAH.

Development of an Echocardiographic Risk-Stratification Index to Predict Heart Failure in Patients With Stable Coronary Artery Disease: The Heart and Soul Study

We sought to determine which transthoracic echocardiographic (TTE) measurements most strongly predict heart failure (HF) and to develop an index for risk stratification in outpatients with coronary artery disease (CAD). Many TTE measurements have been shown to be predictive of HF, and they might be useful if aggregated into a risk-prediction index. We performed TTE in 1,024 outpatients with stable CAD enrolled in the Heart and Soul study and followed them for 4.4 years. With Cox proportional hazard models, we evaluated the association of 15 TTE measurements with subsequent HF hospital stay. Those measurements that independently predicted HF were combined into an index. Variables were defined as normal or abnormal on the basis of dichotomous cutoffs determined from the American Society of Echocardiography. Abnormal variables in each measurement were assigned points on the basis of strength of association with HF. Of the 15 variables, 5 measurements were independent predictors of HF: left ventricular mass index (LVMI), left atrial volume index (LAVI), mitral regurgitation (MR), left ventricular outflow tract velocity-time integral (VTI(LVOT)), and diastolic dysfunction (DD). In multivariate analysis, each of the 5 measurements independently predicted HF: LVMI >90 g/m(2) (hazard ratio [HR]: 4.1; 95% confidence interval [CI]: 2.3 to 7.2, p < 0.0001); pseudo-normal or restrictive DD (HR: 2.9; 95% CI: 1.8 to 4.5, p < 0.0001); VTI(LVOT) <22 mm (HR: 2.2; 95% CI: 1.4 to 3.5, p = 0.0004); mild, moderate, or severe MR (HR: 1.8; 95% CI: 1.2 to 2.8, p = 0.009); and LAVI >29 ml/m(2) (HR: 1.6; 95% CI: 1.0 to 2.5, p < 0.06). Combining these measurements, the Heart Failure Index ranged from 0 to 8, representing risk as follows: 3 points for LVMI, 2 points for DD, and 1 point for VTI(LVOT), MR, and LAVI. Among participants with 0 to 2 points: 4% had HF hospital stays (reference); 3 to 4 points: 10% (HR: 2.4; 95% CI: 1.3 to 4.4, p = 0.003); 5 to 6 points: 24% (HR: 6.2; 95% CI: 3.6 to 10.6, p < 0.0001); 7 to 8 points: 48% (HR: 13.7; 95% CI: 7.2 to 25.9, p < 0.0001). We identified 5 TTE measurements that independently predict HF in patients with stable CAD and combined them as an index that might be useful for risk stratification and serial observations.

The Noninvasive Evaluation of Exercise-induced Changes in Pulmonary Artery Pressure and Pulmonary Vascular Resistance

During exercise, pulmonary artery systolic pressure (PASP) may increase. The purpose of this study was to examine the responses of PASP and pulmonary vascular resistance by Doppler echocardiography during exercise in conditioned athletes and in patients with pulmonary disease. Fifteen participants in each group were evaluated using Doppler echocardiography at rest and during recumbent bicycle exercise. PASP was calculated using 4 times the tricuspid regurgitant velocity squared (TRV)2 and a surrogate for pulmonary vascular resistance was calculated using the equation: pulmonary vascular resistance = TRV/right ventricular outflow tract time-velocity integral. During exercise, PASP increased in both groups with higher values achieved by patients with pulmonary conditions (54.8 vs 70.6 mm Hg, P = .009). At baseline the ratio TRV/right ventricular outflow tract time-velocity integral was 0.2 or less in both the athlete and pulmonary groups. During exercise, the ratio of TRV/right ventricular outflow tract time-velocity integral remained less than 0.2 in the athletes and increased more than 0.2 in the pulmonary group. Doppler echocardiography can be used to discriminate a flow- versus resistance-mediated mechanism for exercised-induced increase in PASP.

A simple method for noninvasive estimation of pulmonary vascular resistance

ObjectivesWe sought to test whether the ratio of peak tricuspid regurgitant velocity (TRV, ms) to the right ventricular outflow tract time-velocity integral (TVIRVOT, cm) obtained by Doppler echocardiography (TRV/TVIRVOT) provides a clinically reliable method to determine pulmonary vascular resistance (PVR). BackgroundPulmonary vascular resistance is an important hemodynamic variable used in the management of patients with cardiovascular and pulmonary disease. Right-heart catheterization, with its associated disadvantages, is required to determine PVR. However, a reliable noninvasive method is unavailable. MethodsSimultaneous Doppler echocardiographic examination and right-heart catheterization were performed in 44 patients. The ratio of TRV/TVIRVOTwas then correlated with invasive PVR measurements using regression analysis. An equation was modeled to calculate PVR in Wood units (WU) using echocardiography, and the results were compared with invasive PVR measurements using the Bland-Altman analysis. Using receiver-operating characteristics curve analysis, a cutoff value for the Doppler equation was generated to determine PVR >2WU. ResultsAs calculated by Doppler echocardiography, TRV/TVIRVOTcorrelated well (r = 0.929, 95% confidence interval 0.87 to 0.96) with invasive PVR measurements. The Bland-Altman analysis between PVR obtained invasively and that by echocardiography, using the equation: PVR= TRV/TVIRVOT× 10 + 0.16 , showed satisfactory limits of agreement (mean 0 ± 0.41). A TRV/TVIRVOTcutoff value of 0.175 had a sensitivity of 77% and a specificity of 81% to determine PVR >2WU. ConclusionsDoppler echocardiography may provide a reliable, noninvasive method to determine PVR.