A novel echocardiographic estimate of pulmonary vascular resistance employing the hydraulic analogy to Ohm's law.

Background: Assessment of pulmonary vascular resistance (PVR) is critical for accurate diagnosis and optimal pharmacotherapy in pulmonary hypertension. We aimed to test the diagnostic performance of a novel, Doppler-based method to evaluate PVR based on Ohm's law (PVRecho) using pragmatic estimates of pulmonary capillary wedge pressure (PCWP). Methods and results: Simultaneous right heart catheterization (RHC) and echocardiography was performed in a derivation cohort of 111 patients in sinus rhythm referred for PH evaluation and PVRecho independently validated in 238 patients. PVRecho was calculated using pulmonary artery mean pressure estimates (PAMPecho) obtained from peak tricuspid gradient employing a fixed right atrial pressure estimate, PCWPecho was estimated as 10 or 20 mmHg using age-related mitral E/A cut-offs and cardiac output from left ventricular outflow. In the derivation cohort, both PAMPecho and PCWPecho estimates demonstrated excellent agreement with catheterization measurements. PVRecho was highly feasible, demonstrated negligible bias and excellent agreement with PVRRHC (Bias = -0.58, SD 2.2 mmHg) and outperformed the Abbas method to identify PVRRHC > 3WU (AUC = 0.85 vs. 0.70; p = 0.02). In the validation cohort, PVRecho preserved good invasive agreement with negligible bias, displayed strong diagnostic performance (AUC = 0.84) and significant ability to distinguish isolated post-capillary from combined post- and pre-capillary pulmonary hypertension (PH) subgroups (AUC = 0.77). Conclusion: PVRecho based on Ohm's law employing pragmatic estimates of PCWPecho demonstrates excellent agreement with invasive reference standard measurements and strong diagnostic ability to identify elevated PVRRHC. This novel approach may be useful during therapy selection to distinguish PH hemodynamic subgroups.

Left atrial reservoir strain improves diagnostic accuracy of the 2016 ASE/EACVI diastolic algorithm in patients with preserved left ventricular ejection fraction: insights from the KARUM haemodynamic database.

AIMS: This study aimed to investigate the incremental value offered by left atrial reservoir strain (LASr) to the 2016 American Society of Echocardiography/European Association of Cardiovascular Imaging (ASE/EACVI) diastolic algorithm to identify elevated left ventricular (LV) filling pressure in patients with preserved ejection fraction (EF). METHODS AND RESULTS: Near-simultaneous echocardiography and right heart catheterization were performed in 210 patients with EF ≥50% in a large, dual-centre study. Elevated filling pressure was defined as invasive pulmonary capillary wedge pressure (PCWP) ≥15 mmHg. LASr was evaluated using speckle-tracking echocardiography. Diagnostic performance of the ASE/EACVI diastolic algorithm was validated against invasive reference and compared with modified algorithms incorporating LASr. Modest correlation was observed between E/e', E/A ratio, and LA volume index with PCWP (r = 0.46, 0.46, and 0.36, respectively; P < 0.001 for all). Mitral e' and TR peak velocity showed no association. The ASE/EACVI algorithm (89% feasibility, 71% sensitivity, 68% specificity) demonstrated reasonable ability (AUC = 0.69) and 68% accuracy to identify elevated LV filling pressure. LASr displayed strong ability to identify elevated PCWP (AUC = 0.76). Substituting TR peak velocity for LASr in the algorithm (69% sensitivity, 84% specificity) resulted in 91% feasibility, 81% accuracy, and stronger agreement with invasive measurements. Employing LASr as per expert consensus (71% sensitivity, 70% specificity) and adding LASr to conventional parameters (67% sensitivity, 84% specificity) also demonstrated greater feasibility (98% and 90%, respectively) and overall accuracy (70% and 80%, respectively) to estimate elevated PCWP. CONCLUSIONS: LASr improves feasibility and overall accuracy of the ASE/EACVI algorithm to discern elevated filling pressures in patients with preserved EF.

Accuracy of echocardiographic estimates of pulmonary artery pressures in pulmonary hypertension: insights from the KARUM hemodynamic database.

Accurate assessment of pulmonary artery (PA) pressures is integral to diagnosis, follow-up and therapy selection in pulmonary hypertension (PH). Despite wide utilization, the accuracy of echocardiography to estimate PA pressures has been debated. We aimed to evaluate echocardiographic accuracy to estimate right heart catheterization (RHC) based PA pressures in a large, dual-centre hemodynamic database. Consecutive PH referrals that underwent comprehensive echocardiography within 3 h of clinically indicated right heart catheterization were enrolled. Subjects with absent or severe, free-flowing tricuspid regurgitation (TR) were excluded. Accuracy was defined as mean bias between echocardiographic and invasive measurements on Bland-Altman analysis for the cohort and estimate difference within ± 10 mmHg of invasive measurements for individual diagnosis. In 419 subjects, echocardiographic PA systolic and mean pressures demonstrated minimal bias with invasive measurements (+ 2.4 and + 1.9 mmHg respectively) but displayed wide limits of agreement (- 20 to + 25 and - 14 to + 18 mmHg respectively) and frequently misclassified subjects. Recommendation-based right atrial pressure (RAP) demonstrated poor precision and was falsely elevated in 32% of individual cases. Applying a fixed, median RAP to echocardiographic estimates resulted in relatively lower bias between modalities when assessing PA systolic (+ 1.4 mmHg; 95% limits of agreement + 25 to - 22 mmHg) and PA mean pressures (+ 1.4 mmHg; 95% limits of agreement + 19 to - 16 mmHg). Echocardiography accurately represents invasive PA pressures for population studies but may be misleading for individual diagnosis owing to modest precision and frequent misclassification. Recommendation-based estimates of RAPmean may not necessarily contribute to greater accuracy of PA pressure estimates.

Can Doppler echocardiography estimate raised pulmonary capillary wedge pressure provoked by passive leg lifting in suspected heart failure?

AIMS: Non-invasive estimation of left ventricular filling pressure (LVFP) during stress is important for explaining exertional symptoms in patients with heart failure (HF). The aim of this study was to evaluate ability of Doppler echocardiographic measures of elevated LVFP with passive leg lifting (PLL) in patients with suspected HF. METHODS: Twenty-nine patients with clinical signs of HF who underwent simultaneous Doppler echocardiography and right heart catheterization (RHC) at rest and during PLL were consecutively investigated. Seventeen patients had normal PCWP (≤15 mmHg) at rest and during PLL and 12 with normal PCWP at rest but >15 mmHg with PLL. Conventional echo and 2D strain were used to assess early diastolic blood flow velocity (E), LV strain rate during early diastole (LVSRe), left atrial SR during atrial contraction (LASRa) and myocardial tissue Doppler velocities to assess lateral e' and further calculate E/e' and E/LVSRe and their relationship with PCWP, at rest and during PLL. RESULTS: Resting LAVI (ß = 0·45, P = 0·009) and LASRa (ß = -0·51, P = 0·004) were independently related to PCWP during PLL. Also, LASRa (ß = -0·77, P<0·001), E/e' (ß = 0·40, P = 0·04) and E/LVSRe (ß = 0·47, P = 0·021) during PLL correlated with PCWP during PLL. Multiple regression analysis identified E/LVSRe (ß = 0·46, P = 0·001) and LASRa (ß = -0·58, P = 0·002) during PLL as being independently associated with PCWP during PLL. CONCLUSION: Left atrial volume and myocardial contraction (LASRa) at rest both predict unstable LV filling pressures measured as raised PCWP when provoked by PLL. Furthermore, LASRa at PLL seems to have the strongest association to PCWP during PLL.

Right and left heart dysfunction predict mortality in pulmonary hypertension.

In pulmonary hypertension (PH), the right heart dysfunction is a strong predictor of adverse clinical outcome, while the role of the left heart is not fully determined. The aim of this study was to identify predictors of mortality in precapillary PH including measures of both right and left heart function. We studied 34 patients (mean age 64 ± 13, range 31-82 years, 24 females) with precapillary PH, all of whom underwent detailed Doppler echocardiographic examination of the right and left heart function using conventional and speckle-tracking echocardiography. Patients were followed up for up to 8 years (mean 4·2 ± 1·9 years). At follow-up, 16 patients survived. Left ventricular (LV) filling time (P = 0·007), pulmonary artery acceleration time (P = 0·009), right atrial pressure (RAP) (P<0·001) and tricuspid regurgitation (TR) severity (P = 0·007) were worse in the deceased group. RV global longitudinal strain (GLS) (P = 0·001), RAP (P≤0·001), LV filling time (P<0·001) and TR severity (P<0·001) were the most accurate predictors, having the largest AUC (>0·65) and carried the highest risk for mortality (P<0·001 for all). The strongest predictors of mortality in precapillary PH indirectly reflect both left and right heart dysfunction including atrial structure and function disturbances. While an interaction pattern is observed, it needs to be confirmed in a larger cohort.

Left Atrial Intrinsic Strain Rate Correcting for Pulmonary Wedge Pressure Is Accurate in Estimating Pulmonary Vascular Resistance in Breathless Patients.

OBJECTIVES: We hypothesized that left atrial deformation during atrial systole (LASRa) correlates with pulmonary capillary wedge pressure (PCWP), thus enabling echo-derived pulmonary vascular resistance (PVR) estimation in a wide range of different subsets of patients. BACKGROUND: Various etiologies of pulmonary hypertension (PH) have different mechanisms and treatments for breathlessness. Irrespective of the location of the underlying pulmonary vascular pathology, pre- or postcapillary, the resulting PH is fairly easy to assess by Doppler echocardiography, but PVR remains a challenge. METHODS: We prospectively included 46 patients (mean age 61 ± 13 years) in sinus rhythm, who underwent right heart catheterization because of dyspnea. According to the NICE guidelines classification, 22 belonged to group 1 pulmonary artery hypertension (PAH), 19 belonged to group 2 congestive heart failure (CHF), 1 belonged to group 4 chronic thromboembolic pulmonary hypertension (CTEPH), and 4 had normal hemodynamics. Simultaneous Doppler echocardiography using spectral, tissue Doppler, and speckle tracking echocardiography techniques for assessing LA structure and function was performed. RESULTS: PCWPrhc correlated with LASRa (r(2) = 0.65, P < 0.001). PCWPecho was calculated using the equation (PCWPecho = 26.12 - 11.09 × LASRa), and the resulting PVR echo strongly correlated with the respective catheter-based measurements PVRrhc (r(2) = 0.69. P < 0.001) with a sensitivity of 85% and specificity of 74% identifying a PVR ≥ 3 WU. CONCLUSIONS: Left atrial strain rate during atrial systole correlates closely with pulmonary capillary wedge pressure and consequently the calculated pulmonary vascular resistance, irrespective of the etiology of PH.

Pulmonary artery acceleration time in identifying pulmonary hypertension patients with raised pulmonary vascular resistance.

BACKGROUND: In patients with pulmonary hypertension (PH), ascertaining raised vascular resistance as a cause is a clinical objective, for which various Doppler-based measurements have been proposed, but with modest accuracy. We hypothesize that pulmonary acceleration time (PAcT) and the ratio of PAcT/peak pulmonary artery systolic pressure (PASP) reflect better the extent of the vascular resistance, compared with other available methods, and can differentiate accurately between pre- and post-capillary PH. METHODS AND RESULTS: We investigated 56 patients (mean age 61 ± 13 years, 23 males) in a simultaneous echocardiography and right heart catheterization (RHC) study. Based on the RHC, pulmonary vascular resistance (PVR), and pulmonary capillary wedge pressure (PCWP), patients were divided into four groups: Group 1 = normal PVR [<3 WU (Wood units)] and PCWP (<12 mmHg), Group 2 = raised PVR but normal PCWP, Group 3 = raised PVR and PCWP; and Group 4 = normal PVR but raised PCWP. We used spectral Doppler to measure PAcT (corrected for heart rate) and to estimate PASP (peak tricuspid regurgitation pressure drop + estimated right atrial pressure of 7 mmHg). We also tested other available methods for assessing PVR. There were small age differences between patient groups but no age difference between Groups 2 and 4. PAcT and PAcT/PASP were both significantly (P = 0.008) reduced in Groups 2 and 3 compared with Groups 1 and 4. PAcT ≤90 had an 84% sensitivity and an 85% specificity in identifying patients with PVR ≥3 WU with a positive and a negative predictive value of 88% and 81%, respectively. The non-linear relationship between PVR and PAcT gave a quadratic r = 0.61, P < 0.001. ROC curve analysis showed PAcT having the best accuracy (83%) in detecting a PVR ≥3 WU. CONCLUSION: PAcT <90 ms can serve as a strong non-invasive predictor of PVR >3 WU, which could differentiate patients with pre- and post-capillary PH.

Echocardiography based estimation of pulmonary vascular resistance in patients with pulmonary hypertension: a simultaneous Doppler echocardiography and cardiac catheterization study.

AIMS: Pulmonary vascular resistance (PVR) is an important measurement for the diagnosis of patients with pulmonary hypertension (PH) but needs accurate determination of mean pulmonary artery pressure (PAMP). We aimed to test the accuracy of a Doppler-derived measurement of PVR, using the conventional invasive equation in patients with PH. METHODS AND RESULTS: We investigated 30 patients undergoing right heart catheterization (RHC), mean age 62 ± 13 years, 21 females, with different diseases; idiopathic pulmonary arterial hypertension (PAH) (n = 5), associated PAH (n = 16), chronic thromboembolic PH (n = 6), interstitial lung disease (n = 2), and after closure of an atrial septal defect (n = 1). Patients with impaired left ventricular systolic function (EF < 50%) or elevated pulmonary capillary wedge pressure (PCWP >15 mmHg on RHC) were excluded. We used the formula: PAMP = PASP(echo) × 0.61 + 2 mmHg, where PASP(echo) is the peak tricuspid regurgitation pressure drop + 10 or 7 mmHg. Pulmonary vascular resistance was then calculated as PAMP(echo)- PCWP/cardiac output. Pulmonary capillary wedge pressure was estimated at 10 mmHg in all cases. The Doppler-derived estimation of PVR(echo) was achievable in 90% of patients, in whom accurate calculation of PAMP was obtainable. Pulmonary vascular resistance echo individual values strongly correlated with those from RHC (r = 0.85, P < 0.001 and r = 0.87, P < 0.001 for the two estimated values for right atrial pressure, respectively). The regression equation using this formula was PVR(rhc) = 0.95 × PVR(echo)- 0.29, and the regression line was close to identity. The Bland-Altman plot showed a good agreement between PVR(echo) and PVR(rhc) values, with a mean difference of -0.66 ± 2.1 Wood unit. CONCLUSION: The proposed Doppler-derived formula for estimating PVR based on the conventionally used invasive equation strongly correlates with invasive gold standard measures.