Ventricular Outflow Tract Velocity Time Research Articles

Association of Left Atrial Function Index with Atrial Fibrillation and Cardiovascular Disease: The Framingham Offspring Study.

BackgroundLeft atrial (LA) size, a marker of atrial structural remodeling, is associated with increased risk for atrial fibrillation (AF) and cardiovascular disease (CVD). LA function may also relate to AF and CVD, irrespective of LA structure. We tested the hypothesis that LA function index (LAFI), an echocardiographic index of LA structure and function, may better characterize adverse LA remodeling and predict incident AF and CVD than existing measures.Methods and ResultsIn 1786 Framingham Offspring Study eighth examination participants (mean age, 66±9 years; 53% women), we related LA diameter and LAFI (derived from the LA emptying fraction, left ventricular outflow tract velocity time integral, and indexed maximal LA volume) to incidence of AF and CVD on follow‐up. Over a median follow‐up of 8.3 years (range, 7.5–9.1 years), 145 participants developed AF and 139 developed CVD. Mean LAFI was 34.5±12.7. In adjusted Cox regression models, lower LAFI was associated with higher risk of incident AF (hazard ratio=3.83, 95% confidence interval=2.23–6.59, lowest [Q1] compared with highest [Q4] LAFI quartile) and over 2‐fold higher risk of incident CVD (hazard ratio=2.20, 95% confidence interval=1.32–3.68, Q1 versus Q4). Addition of LAFI, indexed maximum LA volume, or LA diameter to prediction models for AF or CVD did not significantly improve model discrimination for either outcome.ConclusionsIn our prospective investigation of a moderate‐sized community‐based sample, LAFI, a composite measure of LA size and function, was associated with incident AF and CVD. Addition of LAFI to the risk prediction models for AF or CVD, however, did not significantly improve their performance.

Lack of correlation between left ventricular outflow tract velocity time integral and stroke volume index in mechanically ventilated patients.

To assess the correlation between left ventricular outflow tract velocity time integral (LVOT VTI) and stroke volume index (SVI) calculated by thermodilution methods in ventilated critically ill patients. A prospective, descriptive, multicenter study was performed. Five intensive care units from university hospitals. Patients older than 17 years needing mechanical ventilation and invasive hemodynamic monitoring were included. LVOT VTI was measured by pulsatile Doppler echocardiography. Calculations of SVI were performed through a floating pulmonary artery catheter (PAC) or a Pulse index Contour Cardiac Output (PiCCO®) thermodilution methods. The relation between LVOT VTI and SVI was tested by linear regression analysis. One hundred and fifty-six paired measurements were compared. Mean LVOT VTI was 20.83±4.86cm and mean SVI was 41.55±9.55mL/m2. Pearson correlation index for these variables was r=0.644, p<0.001; ICC was 0.52 (CI 95% 0.4-0.63). When maximum LVOT VTI was correlated with SVI, Pearson correlation index was r=0.62, p<0.001. Correlation worsened for extreme values, especially for those with higher LVOT VTI. LVOT VTI could be a complementary hemodynamic evaluation in selected patients, but does not eliminate the need for invasive monitoring at the present time. The weak correlation between LVOT VTI and invasive monitoring deserves additional assessment to identify the factors affecting this disagreement.

What is the Utility of the Mitral to Left Ventricular Outflow Tract Velocity Time Integral Ratio as a Non–Geometric Indicator of Differential Flow in Isolated Severe Primary and Secondary Mitral Regurgitation?

What is the Utility of the Mitral to Left Ventricular Outflow Tract Velocity Time Integral Ratio as a Non–Geometric Indicator of Differential Flow in Isolated Severe Primary and Secondary Mitral Regurgitation?

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.

Echocardiography allows for analysis of pulmonary arterial flow in mice with congenital diaphragmatic hernia

BackgroundCongenital diaphragmatic hernia (CDH) is a structural birth defect associated with pulmonary hypoplasia and pulmonary arterial hypertension (PAH). We hypothesize that echocardiography provides a method to assess real-time right ventricle (RV) function, remodeling, and pulmonary artery (PA) flow. Materials and methodsSlit3 wild-type (WT) (n = 6) and knockout (KO) (n = 5) mice were analyzed at 2-3 months of age. Mice were anesthetized using isoflurane. Echocardiography was performed to analyze left and right ventricular wall thickness, internal diameter (ID), and function. Color Doppler was used to analyze flow in the PA and across the tricuspid valve. ResultsThere was significant RV dilation in the KO mice versus WT, with an average RVID of 1.99 mm versus 1.26 mm, respectively (P = 0.007). Flow in the PA of KO mice was altered compared to WT, with elevated PA velocity time indices, 30.68 mm versus 22.13 mm (P = 0.012), elevated PA peak velocities, 952.61 mm/s versus 628.73 mm/s (P = 0.003), and decreased pulmonary acceleration times, 8.94 ms versus 16.18 ms (P = 0.002), respectively. Pulmonary vascular resistance, calculated by measuring tricuspid regurgitation peak velocity and right ventricular outflow tract velocity time index, was increased in KO versus WT mice, 17.61 mm2/s versus 8.91 mm2/s (P = 0.003), respectively. ConclusionsSlit3 KO mice with CDH show evidence of PAH and resultant RV dilation. Using direct cardiac puncture, elevated RV systolic pressures have been demonstrated in KO mice as evidence of PAH. Echocardiography allows direct analysis of the PA and real-time RV function without sacrifice of the mouse. This mode of evaluation allows longitudinal study in mice with PAH and CDH.

Impact of stroke volume assessment by integrating multi-detector computed tomography and Doppler data on the classification of aortic stenosis

BackgroundThe prevalence of low flow low gradient (LFLG) severe aortic stenosis (AS) may be overrated due to underestimation of stroke volume in two-dimensional (2D) echocardiography. The implications of 3D imaging on stroke volume calculation for AS classification have not been elucidated. Integrating multi-detector computed tomography (MDCT) and Doppler data may improve diagnostic accuracy in patients with LFLG AS. MethodsA total of 186 patients with severe AS evaluated for transcatheter aortic valve replacement were classified according to indexed stroke volume (SVI, cut-off 35mL/m2) and mean transaortic pressure gradient (cut-off 40mmHg). SVI was calculated using a) the biplane Simpson's method, b) left ventricular outflow tract (LVOT) velocity time integral (VTI) and LVOT diameter determined by 2D echocardiography, or c) LVOT VTI and LVOT area planimetered by MDCT. ResultsSVI assessed by the biplane Simpson's method was smaller than that obtained from 2D echocardiography LVOT diameter (29.5±0.6 vs 34.9±0.8mL/m2, p<0.001). The latter was smaller than SVI calculated by integrating MDCT and Doppler data (47.5±1.4mL/m2, p<0.001). LFLG and paradoxical LFLG severe AS were diagnosed in 42.5% and 27.4% of patients using the biplane Simpson's method, in 30.1% and 16.7% using 2D echocardiography LVOT diameter, and in 17.2% and 8.1% when integrating MDCT and Doppler data. ConclusionsThe prevalence of LFLG and paradoxical LFLG severe AS was overestimated by 2.5- and 3.4-fold based on 2D echocardiography alone. Integration of MDCT and Doppler data should be considered for stroke volume assessment in the classification of severe AS.

Clinical and Echocardiographic Correlates of Left Atrial Function Index: The Framingham Offspring Study

Left atrial (LA) remodeling is a predictor of cardiovascular disease (CVD). We performed measurement of the LA function index (LAFI), a composite measure of LA structure and function, in a community-based cohort and here report the distribution and cross-sectional correlates of LAFI. In 1,719 Framingham Offspring Study participants (54% women, mean age 66±9years), we derived LAFI from the LA emptying fraction, left ventricular (LV) outflow tract velocity time integral, and indexed maximal LA volume. We used multivariable linear regression to assess the clinical and echocardiographic correlates of LAFI adjusting for age, sex, anthropometric measurements, and CVD risk factors. The average LAFI was 35.2±12.1. Overall, LAFI declined with advancing age (β=-0.27, P<.001). LAFI was significantly higher (37.5±11.6) in a subgroup of participants free of CVD and CVD risk factors compared with those with either of these conditions (34.5±12.2). In multivariable models, LAFI was inversely related to antihypertensive use (β=-1.26, P=.038), prevalent atrial fibrillation (β=-4.46, P=.001), heart failure (β=-5.86, P=.008), and coronary artery disease (β=-2.01, P=.046). In models adjusting for echocardiographic variables, LAFI was directly related to LV ejection fraction (β=14.84, P<.001) and inversely related to LV volume (β=-7.03, P<.001). LAFI was inversely associated with antihypertensive use and prevalent CVD and was related to established echocardiographic traits of LV remodeling. Our results offer normative ranges for LAFI in a white community-based sample and suggest that LAFI represents a marker of pathological atrial remodeling.

Left ventricular outflow tract velocity time integral outperforms ejection fraction and Doppler-derived cardiac output for predicting outcomes in a select advanced heart failure cohort

BackgroundLeft ventricular outflow tract velocity time integral (LVOT VTI) is a measure of cardiac systolic function and cardiac output. Heart failure patients with low cardiac output are known to have poor cardiovascular outcomes. Thus, extremely low LVOT VTI may predict heart failure patients at highest risk for mortality.MethodsPatients with heart failure and extremely low LVOT VTI were identified from a single-center database. Baseline characteristics and heart failure related clinical outcomes (death, LVAD) were obtained at 12 months. Correlation between clinical endpoints and the following variables were analyzed: ejection fraction (EF), pulmonary artery systolic pressure (PASP), NYHA class, renal function, Doppler cardiac output (CO), and LVOT VTI.ResultsStudy cohort consisted of 100 patients. At the 12-month follow up period, 30 events (28 deaths, 2 LVADs) were identified. Occurrence of death and LVAD implantation was statistically associated with a lower LVOT VTI (p = 0.039) but not EF (p = 0.169) or CO (p = 0.217). In multivariate analysis, LVOT VTI (p = 0.003) remained statistically significant, other significant variables were age (p = 0.033) and PASP (p = 0.022). Survival analysis by LVOT VTI tertile demonstrated an unadjusted hazard ratio of 4.755 (CI 1.576-14.348, p = 0.006) for combined LVAD and mortality at one year.ConclusionsExtremely low LVOT VTI strongly predicts adverse outcomes and identifies patients who may benefit most from advanced heart failure therapies.

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.

LVOT-VTI is a Useful Indicator of Low Ventricular Function in Young Patients.

Left ventricular outflow tract velocity time integral (LVOT-VTI), a Doppler-derived measure of stroke distance, is used as a surrogate marker of cardiac function in adults. LVOT-VTI is easily obtained, independent of ventricular geometry and wall motion abnormalities. We investigated the relationship between LVOT-VTI and conventional measures of function in young patients by comparing controls to children with dilated cardiomyopathy (DCM). Sixty-two healthy and 52 DCM patients over 1year were studied retrospectively. The average pulsed (PW) and continuous wave (CW) LVOT-VTIs from apical views were measured from three cycles. Body surface area (BSA) and Ejection fraction (EF) were obtained. We compared LVOT-VTIs between study and control groups and assessed BSA's impact on LVOT-VTI. The entire cohort was classified into three levels of LV function which were compared. We determined LVOT-VTI cutoff values that indicated an EF<50%. The mean PW-LVOT-VTI in the DCM group was significantly lower than that of the normal group (0.15 vs. 0.18m; p<0.0012). The mean CW-LVOT-VTI was significantly lower in DCM (0.20 vs. 0.24m; p<0.0001). There was no impact of BSA on LVOT-VTI except when comparing BSA and CW-LVOT-VTI in the normal group. There was a positive relationship between LVOT-VTI and EF for PW (Rs=0.29, p=0.0022) and CW (Rs=0.22, p=0.0364) and a difference in mean LVOT-VTI between EF groups (p<0.0001). ROC analysis demonstrated that PW-LVOT-VTI<0.17m (AUC=0.73; p<0.0001) and CW-LVOT-VTI<0.22m (AUC=0.76; p<0.0001) was associated with EF<50%. This study indicates that LVOT-VTI can be a useful alternative measure of LV performance in children over 1year.

123 - Right Ventricular Outflow Tract Velocity Time Integral to Pulmonary Artery Systolic Pressure Ratio: A New Non-Invasive Metric of Pulmonary Arterial Compliance

123 - Right Ventricular Outflow Tract Velocity Time Integral to Pulmonary Artery Systolic Pressure Ratio: A New Non-Invasive Metric of Pulmonary Arterial Compliance

LVOT VTI OUTPERFORMS EJECTION FRACTION AND DOPPLER-DERIVED CARDIAC OUTPUT FOR PREDICTING OUTCOMES IN A SELECT ADVANCED HEART FAILURE COHORT

Left ventricular outflow tract velocity time integral (LVOT VTI) correlates with stroke volume, reflecting cardiac pump systolic function. In heart failure patients with reduced LVOT VTI, extremely low LVOT VTI was hypothesized to predict increased mortality and need for left ventricular assist

36th International Symposium on Intensive Care and Emergency Medicine : Brussels, Belgium. 15-18 March 2016.

36th International Symposium on Intensive Care and Emergency Medicine : Brussels, Belgium. 15-18 March 2016.

Comparison between respiratory changes in the inferior vena cava diameter and pulse pressure variation to predict fluid responsiveness in postoperative patients

PurposeThe objective of our study was to assess the reliability of the distensibility index of the inferior vena cava (dIVC) as a predictor of fluid responsiveness in postoperative, mechanically ventilated patients and compare its accuracy with that of the pulse pressure variation (PPV) measurement. Materials and methodsWe included postoperative mechanically ventilated and sedated patients who underwent volume expansion with 500mL of crystalloids over 15minutes. A response to fluid infusion was defined as a 15% increase in the left ventricular outflow tract velocity time integral according to transthoracic echocardiography. The inferior vena cava diameters were recorded by a subcostal view using the M-mode and the PPV by automatic calculation. The receiver operating characteristic (ROC) curves were generated for the baseline dIVC and PPV. ResultsTwenty patients were included. The area under the ROC curve for dIVC was 0.84 (95% confidence interval, 0.63-1.0), and the best cutoff value was 16% (sensitivity, 67%; specificity, 100%). The area under the ROC curve for PPV was 0.92 (95% confidence interval, 0.76-1.0), and the best cutoff was 12.4% (sensitivity, 89%; specificity, 100%). A noninferiority test showed that dIVC cannot replace PPV to predict fluid responsiveness (P=.28). ConclusionThe individual PPV discriminative properties for predicting fluid responsiveness in postoperative patients seemed superior to those of dIVC.

Transthoracic echocardiography in the evaluation of pediatric pulmonary hypertension and ventricular dysfunction.

Transthoracic echocardiography (TTE) is the most accessible noninvasive diagnostic procedure for the initial assessment of pediatric pulmonary hypertension (PH). This review focuses on principles and use of TTE to determine morphologic and functional parameters that are also useful for follow-up investigations in pediatric PH patients. A basic echocardiographic study of a patient with PH commonly includes the hemodynamic calculation of the systolic pulmonary artery pressure (PAP), the mean and diastolic PAP, the pulmonary artery acceleration time, and the presence of a pericardial effusion. A more detailed TTE investigation of the right ventricle (RV) includes assessment of its size and function. RV function can be evaluated by RV longitudinal systolic performance (e.g., tricuspid annular plane systolic excursion), the tricuspid regurgitation velocity/right ventricular outflow tract velocity time integral ratio, the fractional area change, tissue Doppler imaging-derived parameters, strain measurements, the systolic-to-diastolic duration ratio, the myocardial performance (Tei) index, the RV/left ventricle (LV) diameter ratio, the LV eccentricity index, determination of an enlarged right atrium and RV size, and RV volume determination by 3-dimensional echocardiography. Here, we discuss the potential use and limitations of TTE techniques in children with PH and/or ventricular dysfunction. We suggest a protocol for TTE assessment of PH and myocardial function that helps to identify PH patients and their response to pharmacotherapy. The outlined protocol focuses on the detailed assessment of the hypertensive RV; RV-LV crosstalk must be analyzed separately in the evaluation of different pathologies that account for pediatric PH.

Improved Cardiac Output with Right Ventricular Septal Pacing in a Patient with Right Bundle Branch Block and Left Ventricular Dysfunction

Alternate site pacing improved the left ventricular outflow tract velocity time integral compared to native rhythm in a patient with ischemic cardiomyopathy and severe left ventricular dysfunction with underlying right bundle branch block.

Nurse-delivered focused echocardiography to determine intravascular volume status in a deployed maritime critical care unit

Focused echocardiography is increasingly used by clinicians to guide fluid resuscitation. The UK Defence Medical Services (DMS) have adopted focused echocardiography as a tool to guide flow assessment and resuscitation in deployed critical care. We aimed to explore whether two focused echo techniques, namely Inferior Vena Cava (IVC) and Left Ventricular Outflow Tract Velocity Time integer (LVOT VTi) respiratory variability could be taught to a group of critical care nurses without previous exposure to ultrasound imaging. After a five-week program of training, validation was carried out on healthy volunteers. The mentor, an accredited focused echo trainer, and six nurses performed a total of forty-eight scans on eleven volunteers. The mentor and students acquired subcostal long axis views of the IVC and apical five chamber views using a high frequency linear ultrasound probe. Mean values from three measurements were obtained for IVC diameter and LVOT VTi. Minimum and maximum values were recorded for both variables across a full respiratory cycle. Echo images were saved and at least two images for each student were reviewed offline by an accredited echo-training supervisor. In all cases students were able to obtain adequate echo windows. There was good correlation between values recorded by the mentor and students for both IVC diameter (r = 0.90, p < 0.001) and LVOT VTi (r = 0.77, p < 0.001). Bland Altman analysis showed good correlation with minimal bias for VTi measurements. There was some increase in bias for IVC measurements below 1.2 cm. In summary, we found that these skills for assessing intravascular volume status could be acquired in a relatively short time by specialist nurses without previous experience, and that results were comparable to those produced by an experienced practitioner.

Abstract 19078: Early Predictors of Survival to Heart Transplantation in Patients With Amyloid Light-chain Cardiomyopathy

Background: Amyloid cardiomyopathy progresses more rapidly and has different manifestations than more common cardiomyopathies. Nevertheless, survival of selected cardiac amyloid patients after orthotopic heart transplantation (OHT) followed by autologous stem cell transplant is similar to other restrictive cardiomyopathies. The importance of clinical presentation and pre-transplantation characteristics on outcome in patients with AL amyloid cardiomyopathy evaluated for heart transplantation is still not well defined. Methods: The impact of echocardiographic, hemodynamic, and clinical parameters on outcome in 46 patients evaluated for OHT and enrolled in the International Consortium for Cardiac Amyloid Transplant (iCCAT) database was studied. Cox proportional hazards models of time to death were used. End point was death after transplant evaluation censored at transplant. Results: The median age at the time of transplant evaluated was 57.6 (+/- 9.6) years, and the mean time from presentation to listing was 27 (+/- 26) days. 19 (41%) patients underwent OHT after an average wait time of 72 days. Univariate risk factors associated with death after initial evaluation were cardiac output (p=0.012), right ventricular stroke work index (p=0.033), left ventricular end diastolic dimension (p=0.024), left ventricular outflow tract velocity time integral (p=0.019), mean arterial pressures (p=0.005), NT pro-BNP (p=0.007), presence of pleural effusion (p=0.005), as well as elevated kappa and lambda serum free light chain concentrations (p=0.004). Whereas left ventricular ejection fraction did not correlate with death after evaluation, increased right ventricular wall thickness remained a strong mortality predictor in a multivariate model with light chain difference and cardiac output (HR 1.6 for every 1 mm increase in thickness, p=0.017). Conclusions: Pleural involvement, high light chain burden, and right ventricular infiltration predicted death while awaiting a donor organ and may be markers of more systemic disease. Ultimately, this could affect transplant candidate selection and allocation strategies.

Correlation between twofold left ventricular outflow tract-velocity time integral and stroke volume index in mechanicaly ventilated patients

Ultrasound is a non-invasive and bedside accessible method of cardiac function monitoring. Cardiac echocardiography has several limitations due to difficulties to obtain an acceptable acoustic window in critical care settings. Left ventricular outflow tract (LVOT) velocity time integral (VTI) can be measured in most critical care patient and is an useful tool for this purpose. Calculations of cardiac output needing aortic valve area are strongly dependent on skills and observers [1]. We hypothesize that twofold LVOT-VTI is an accurate calculation of stroke volume index (SVI).

Noninvasive assessment of pulmonary vascular resistance by echocardiography in chronic thromboembolic pulmonary hypertension.

Pulmonary vascular resistance (PVR) is an important parameter in the management of patients with chronic thromboembolic pulmonary hypertension (CTEPH), and numerous noninvasive methods for PVR prediction have been proposed. However, a systematic evaluation of the methods that are specific for CTEPH has not been conducted. We compared a variety of echocardiography-derived prediction indices with direct right heart catheterization (RHC) to identify the most reliable noninvasive indicator of PVR in patients with CTEPH. Echocardiography and RHC were performed sequentially in 40 patients (mean age: 62.4±11.4 years; 30 females) with CTEPH. We measured the peak flow velocity of tricuspid regurgitation (TRV), tricuspid regurgitation pressure gradient (TRPG), right ventricular outflow tract (RVOT) time-velocity integral (TVIRVOT), left ventricular outflow tract (LVOT) time-velocity integral (TVILVOT), cardiac output at RVOT (CORVOT), and the LVOT (COLVOT) using echocardiography. The parameters TRV/TVIRVOT, TRV/TVILVOT, TRV/CORVOT, TRV/COLVOT, TRPG/TVIRVOT, TRPG/TVILVOT, TRPG/CORVOT, and TRPG/COLVOT were then calculated to predict the PVR. Finally, correlations between these echocardiographic predictors of PVR and the PVR data obtained from RHC (PVRRHC) were assessed. The mean pulmonary arterial pressure and PVRRHC were 32.1±11.4mmHg and 5.4±2.9 Wood units, respectively. TRV/TVIRVOT, TRV/TVILVOT, TRV/COLVOT, TRPG/TVIRVOT, TRPG/TVILVOT, TRPG/CORVOT, and TRPG/COLVOT were all significantly correlated with the PVRRHC, and TRPG/COLVOT was the most strongly correlated with the PVRRHC (r=0.807, p<0.001). Echocardiographic measurement of TRPG/COLVOT is a reliable noninvasive predictor of PVR in CTEPH patients.