Interventricular Septal Angle Research Articles

Ventricular interdependent phenotype of mixed Cpc‐pulmonary hypertension and HFpEF with normal left atrium: Impact on CPET metrics and clinical outcomes

AbstractAmong 45 CpcPH/heart failure with preserved ejection fraction participants, 11 with normal left atrium (compared to 34 with abnormal left atrium, p < 0.05 for all) had low left ventricle (LV) transmural pressure (2.9 ± 2.4 vs. 6.2 ± 2.9 mmHg), and increased right ventricle (RV):LV ratio (2.41 ± 1.09 vs. 1.46 ± 0.66) and interventricular septal angle (149 ± 8 vs. 136 ± 10), indicating exaggerated ventricular interdependence from a dilated RV.

Cardiac Magnetic Resonance Imaging for the Evaluation of Pulmonary Hypertension

Abstract Purpose Evaluate the utility of cardiac magnetic resonance imaging for noninvasive estimation of the key hemodynamic parameters that are measured by the right heart catheterization i.e. mean pulmonary artery pressure, pulmonary artery wedge pressure and pulmonary vascular resistance through cardiac magnetic resonance based numerical models. Materials and Methods 29 pulmonary hypertension patients, fitting the inclusion criteria were randomly selected and included in the study. CMR Imaging and right- sided heart catheterization (RHC) were performed within 1 month. 3 Cardiac MRI based models in literature that showed high accuracy were tested. Two equations for mPAP calculation; mPAP= - 231.423 + loge inter-ventricular septal angle X 53.8 + log10 ventricular mass index (right ventricular mass/left ventricular mass) X 8.708 + diastolic pulmonary artery area X 0.009 and mPAP = –4.6 + (interventricular septal angle × 0.23) + (ventricular mass index × 16.3). One equation for PAWP; PAWP = 6.43 + LA volume index x 0.22. Results The Pearson correlation test correlation between invasively quantified and CMR-estimated mPAP had good correlation with r = 0.594 and r = 0.599 (p < 0.001) for CMR based mPAP model 1 and 2, respectively. While, Altman and Bland test showed that The mean bias between the RHC-derived and CMR-estimated mPAP was 7.9 (agreement interval -24.8 to 40.6 mmHg) and mean bias -3 (agreement interval -34.8 to 28.2 mmHg) for CMR based mPAP model 1 and 2, respectively. There was no correlation between invasively quantified and CMR-estimated PAWP with (p = 0.092) for CMR based PAWP model. The mean bias between the RHC- derived and CMR-estimated PAWP was 2.4 (agreement interval –13.5 to 18.2 mmHg). The correlation between invasively calculated and CMR-estimated PVR had good correlation with r = 0.703 and r = 0.704 (p < 0.001) for CMR based PVR model 1 and 2, respectively. The mean bias between the RHC-derived and CMR- estimated mPAP was 0.6 (agreement interval -11.6 to 12.8 mmHg) and mean bias -1.3 (agreement interval -12.1 to 9.5 mmHg) for CMR based mPAP model 1 and 2, respectively. Conclusion our results showed good correlations between CMR findings and RHC as regard mPAP and PVR. Thus Non-invasive estimation of mPAP, PAWP and PVR using CMR is feasible but needs further studies to improve accuracy.

The use of cardiac magnetic resonance imaging for the evaluation of pulmonary hypertension

Purpose Evaluate the utility of cardiac magnetic resonance imaging to estimate the principle hemodynamic parameters that are measured by right heart catheterization in a noninvasive manner i.e. mean pulmonary artery pressure, pulmonary vascular resistance and pulmonary artery wedge pressure through cardiac magnetic resonance based numerical models. Materials and methods 29 pulmonary hypertension patients, fitting the inclusion criteria were randomly selected and included in the study. CMR Imaging and right side heart catheter (RHC) were performed within one month. 3 Cardiac MRI based models in literature that showed high accuracy were tested. Two equations for mPAP calculation; mPAP=-231.423 + 53.8(loge inter-ventricular septal angle)+log10(right ventricular mass divided by left ventricular mass) i.e ventricular mass index X 8.708+area of pulmonary artery in diastole X 0.009 and mPAP = –4.6+(0.32*septal angle)+(ventricular mass index × 16.3). One equation for PAWP; PAWP = left atrial volume index +6.43 × 0.22. Results The Altman and Bland correlation between mPAP invasively measured and CMR-estimated mPAP had good correlation with r= 0.594 and r=0.599 (P<0.001) for CMR based mPAP model 1 and 2, respectively. The calculated mean bias between the RHC-derived and CMR-estimated mPAP was 7.9 (agreement interval -24.8 to 40.6 mm Hg) and mean bias -3 (agreement interval -34.8 to 28.2 mm Hg) for CMR based mPAP model 1 and 2, respectively. There was no correlation between invasively measured and CMR-estimated PAWP with (P =0.092) for CMR based PAWP model. The mean bias between the RHC-derived and CMR-estimated PAWP was 2.4 (agreement interval –13.5 to 18.2 mm Hg). The correlation between invasively calculated and CMR-estimated PVR had good correlation with r=0.703 and r=0.704 (P<0.001) for CMR based PVR model 1 and 2, respectively. The mean bias between the RHC-measured and CMR-estimated mPAP was 0.6 (agreement interval -11.6 to 12.8 mm Hg) and mean bias -1.3 (agreement interval -12.1 to 9.5 mm Hg) for CMR based mPAP model 1 and 2, respectively. Conclusion our results showed good correlations between CMR findings and RHC as regard mPAP and PVR. Thus, estimation of mPAP, PAWP and PVR non-invasively using CMR is feasible but needs further studies to improve accuracy.

Non-invasive detection of severe PH in lung disease using magnetic resonance imaging.

Severe pulmonary hypertension (mean pulmonary artery pressure ≥35 mmHg) in chronic lung disease (PH-CLD) is associated with high mortality and morbidity. Data suggesting potential response to vasodilator therapy in patients with PH-CLD is emerging. The current diagnostic strategy utilises transthoracic Echocardiography (TTE), which can be technically challenging in some patients with advanced CLD. The aim of this study was to evaluate the diagnostic role of MRI models to diagnose severe PH in CLD. 167 patients with CLD referred for suspected PH who underwent baseline cardiac MRI, pulmonary function tests and right heart catheterisation were identified. In a derivation cohort (n = 67) a bi-logistic regression model was developed to identify severe PH and compared to a previously published multiparameter model (Whitfield model), which is based on interventricular septal angle, ventricular mass index and diastolic pulmonary artery area. The model was evaluated in a test cohort. The CLD-PH MRI model [= (-13.104) + (13.059 * VMI)-(0.237 * PA RAC) + (0.083 * Systolic Septal Angle)], had high accuracy in the test cohort (area under the ROC curve (0.91) (p < 0.0001), sensitivity 92.3%, specificity 70.2%, PPV 77.4%, and NPV 89.2%. The Whitfield model also had high accuracy in the test cohort (area under the ROC curve (0.92) (p < 0.0001), sensitivity 80.8%, specificity 87.2%, PPV 87.5%, and NPV 80.4%. The CLD-PH MRI model and Whitfield model have high accuracy to detect severe PH in CLD, and have strong prognostic value.

Diagnosis of Pulmonary Hypertension with Cardiac MRI: Derivation and Validation of Regression Models.

PurposeTo derive and test multiparametric cardiac MRI models for the diagnosis of pulmonary hypertension (PH).Materials and MethodsImages and patient data from consecutive patients suspected of having PH who underwent cardiac MRI and right-sided heart catheterization (RHC) between 2012 and 2016 were retrospectively reviewed. Of 2437 MR images identified, 603 fit the inclusion criteria. The mean patient age was 61 years (range, 18–88 years; mean age of women, 60 years [range, 18–84 years]; mean age of men, 62 years [range, 22–88 years]). In the first 300 patients (derivation cohort), cardiac MRI metrics that showed correlation with mean pulmonary arterial pressure (mPAP) were used to create a regression algorithm. The performance of the model was assessed in the 303-patient validation cohort by using receiver operating characteristic (ROC) and χ2 analysis.ResultsIn the derivation cohort, cardiac MRI mPAP model 1 (right ventricle and black blood) was defined as follows: −179 + loge interventricular septal angle × 42.7 + log10 ventricular mass index (right ventricular mass/left ventricular mass) × 7.57 + black blood slow flow score × 3.39. In the validation cohort, cardiac MRI mPAP model 1 had strong agreement with RHC-measured mPAP, an intraclass coefficient of 0.78, and high diagnostic accuracy (area under the ROC curve = 0.95; 95% confidence interval [CI]: 0.93, 0.98). The threshold of at least 25 mm Hg had a sensitivity of 93% (95% CI: 89%, 96%), specificity of 79% (95% CI: 65%, 89%), positive predictive value of 96% (95% CI: 93%, 98%), and negative predictive value of 67% (95% CI: 53%, 78%) in the validation cohort. A second model, cardiac MRI mPAP model 2 (right ventricle pulmonary artery), which excludes the black blood flow score, had equivalent diagnostic accuracy (ROC difference: P = .24).ConclusionMultiparametric cardiac MRI models have high diagnostic accuracy in patients suspected of having pulmonary hypertension.Published under a CC BY 4.0 license.Online supplemental material is available for this article.See also the editorial by Colletti in this issue.

Identifying At-Risk Patients with Combined Pre- and Postcapillary Pulmonary Hypertension Using Interventricular Septal Angle at Cardiac MRI.

PurposeTo assess interventricular septal (IVS) angle in the identification of combined pre- and postcapillary pulmonary hypertension (Cpc-PH) in patients with pulmonary hypertension (PH) due to left-sided heart disease.Materials and MethodsIn this retrospective study, consecutive, incident patients suspected of having PH underwent same-day right-sided heart catheterization (RHC) and MRI at a PH referral center between April 2012 and April 2017. The diagnostic accuracy of the IVS angle to identify Cpc-PH in patients with pulmonary arterial wedge pressure (PAWP) greater than 15 mmHg was assessed by using receiver operator characteristic curves, sensitivity, specificity, and negative and positive predictive values. IVS angle also was assessed as a predictor of all-cause mortality by using Cox uni- and multivariable proportional hazards regression.ResultsA total of 708 patients underwent same-day MRI and RHC, and 171 patients had PAWP greater than 15 mmHg. Mean age was 70 years (range, 21–90 years) (women: mean age, 69 years; range, 21–88 years) (men: mean age, 71 years; range, 43–90 years). Systolic IVS angle correlated with diastolic pulmonary gradient (DPG) (r = 0.739, P < .001). Receiver operating characteristic curve analysis showed septal angle enabled identification of Cpc-PH (DPG ≥ 7), with an area under the receiver operating characteristic curve of 0.911 (P < .001). A 160° threshold, derived from the first half of patients with raised PAWP, enabled identification of a DPG of at least 7 mmHg with 67% sensitivity and 93% specificity (P < .001) in the second cohort of patients with raised PAWP. IVS angle was predictive of all-cause mortality (standardized univariable hazard ratio, 1.615; P < .01).ConclusionThe systolic interventricular septal angle is elevated in patients with combined pre- and postcapillary pulmonary hypertension and enables one to predict those patients who have PH due to left-sided heart disease who have an increased risk of death.Published under a CC BY 4.0 license.Online supplemental material is available for this article.

Diagnostic and prognostic significance of cardiovascular magnetic resonance native myocardial T1 mapping in patients with pulmonary hypertension

BackgroundNative T1 may be a sensitive, contrast-free, non-invasive cardiovascular magnetic resonance (CMR) marker of myocardial tissue changes in patients with pulmonary artery hypertension. However, the diagnostic and prognostic value of native T1 mapping in this patient group has not been fully explored. The aim of this work was to determine whether elevation of native T1 in myocardial tissue in pulmonary hypertension: (a) varies according to pulmonary hypertension subtype; (b) has prognostic value and (c) is associated with ventricular function and interaction.MethodsData were retrospectively collected from a total of 490 consecutive patients during their clinical 1.5 T CMR assessment at a pulmonary hypertension referral centre in 2015. Three hundred sixty-nine patients had pulmonary hypertension [58 ± 15 years; 66% female], an additional 39 had pulmonary hypertension due to left heart disease [68 ± 13 years; 60% female], 82 patients did not have pulmonary hypertension [55 ± 18; 68% female]. Twenty five healthy subjects were also recruited [58 ±4 years); 51% female]. T1 mapping was performed with a MOdified Look-Locker Inversion Recovery (MOLLI) sequence. T1 prognostic value in patients with pulmonary arterial hypertension was assessed using multivariate Cox proportional hazards regression analysis.ResultsPatients with pulmonary artery hypertension had elevated T1 in the right ventricular (RV) insertion point (pulmonary hypertension patients: T1 = 1060 ± 90 ms; No pulmonary hypertension patients: T1 = 1020 ± 80 ms p < 0.001; healthy subjects T1 = 940 ± 50 ms p < 0.001) with no significant difference between the major pulmonary hypertension subtypes. The RV insertion point was the most successful T1 region for discriminating patients with pulmonary hypertension from healthy subjects (area under the curve = 0.863) however it could not accurately discriminate between patients with and without pulmonary hypertension (area under the curve = 0.654). T1 metrics did not contribute to prediction of overall mortality (septal: p = 0.552; RV insertion point: p = 0.688; left ventricular free wall: p = 0.258). Systolic interventricular septal angle was a significant predictor of T1 in patients with pulmonary hypertension (p < 0.001).ConclusionsElevated myocardial native T1 was found to a similar extent in pulmonary hypertension patient subgroups and is independently associated with increased interventricular septal angle. Native T1 mapping may not be of additive value in the diagnostic or prognostic evaluation of patients with pulmonary artery hypertension.

Non-invasive methods for estimating mPAP in COPD using cardiovascular magnetic resonance imaging

PurposePulmonary hypertension (PH) is associated with a poor outcome in chronic obstructive pulmonary disease (COPD) and is diagnosed invasively. We aimed to assess the diagnostic accuracy and prognostic value of non-invasive cardiovascular magnetic resonance (CMR) models.MethodsPatients with COPD and suspected PH, who underwent CMR and right heart catheter (RHC) were identified. Three candidate models were assessed: 1, CMR-RV model, based on right ventricular (RV) mass and interventricular septal angle; 2, CMR PA/RV includes RV mass, septal angle and pulmonary artery (PA) measurements; 3, the Alpha index, based on RV ejection fraction and PA size.ResultsOf 102 COPD patients, 87 had PH. The CMR-PA/RV model had the strongest diagnostic accuracy (sensitivity 92%, specificity 80%, positive predictive value 96% and negative predictive value 63%, AUC 0.93, p<0.0001). Splitting RHC-mPAP, CMR-RV and CMR-PA/RV models by 35mmHg gave a significant difference in survival, with log-rank chi-squared 5.03, 5.47 and 7.10. RV mass and PA relative area change were the independent predictors of mortality at multivariate Cox regression (p=0.002 and 0.030).ConclusionCMR provides diagnostic and prognostic information in PH-COPD. The CMR-PA/RV model is useful for diagnosis, the RV mass index and PA relative area change are useful to assess prognosis.Key Points• Pulmonary hypertension is a marker of poor outcome in COPD.• MRI can predict invasively measured mean pulmonary artery pressure.• Cardiac MRI allows for estimation of survival in COPD.• Cardiac MRI may be useful for follow up or future trials.• MRI is potentially useful to assess pulmonary hypertension in patients with COPD.

Interventricular septal angle can be used to predict which patients have combined postcapillary or precapillary pulmonary hypertension in left heart disease

Background A transpulmonary gradient (TPG)>12mmHg is thought to represent evidence of vascular change beyond that expected from passive pulmonary venous congestion in patients with pulmonary hypertension and left heart disease (PH-LHD). However recent studies found those with a diastolic pressure gradient (DPG) >6 to have a worse survival. This has led to a change in the recent guidelines suggesting 2 types of PH-LHD: “isolated post-capillary PH” (pulmonary arterial wedge pressure (PAWP)>15 mm Hg and DPG 15 mm Hg and DPG≥7 mmHg). It would be advantageous if a non-invasive method of predicting DPG could be found for both prognostication and to identify potential patients for clinical trials of targeted therapies. Our aim was investigate the utility of cardiac magnetic resonance (CMR) imaging for estimation of DPG in patients with PH-LHD.

Noninvasive Estimation of PA Pressure, Flow, and Resistance With CMR Imaging: Derivation and Prospective Validation Study From the ASPIRE Registry

The aim of this study was to develop a composite numerical model based on parameters from cardiac magnetic resonance (CMR) imaging for noninvasive estimation of the key hemodynamic measurements made at right heart catheterization (RHC). Diagnosis and assessment of disease severity in patients with pulmonary hypertension is reliant on hemodynamic measurements at RHC. A robust noninvasive approach that can estimate key RHC measurements is desirable. A derivation cohort of 64 successive, unselected, treatment naive patients with suspected pulmonary hypertension from the ASPIRE (Assessing the Spectrum of Pulmonary Hypertension Identified at a Referral Centre) Registry, underwent RHC and CMR within 12 h. Predicted mean pulmonary arterial pressure (mPAP) was derived using multivariate regression analysis of CMR measurements. The model was tested in an independent prospective validation cohort of 64 patients with suspected pulmonary hypertension. Surrogate measures of pulmonary capillary wedge pressure (PCWP) and cardiac output (CO) were estimated by left atrial volumetry and pulmonary arterial phase contrast imaging, respectively. Noninvasive pulmonary vascular resistance (PVR) was calculated from the CMR-derived measurements, defined as: (CMR-predicted mPAP - CMR-predicted PCWP)/CMR phase contrast CO. The following composite statistical model of mPAP was derived: CMR-predicted mPAP = -4.6 + (interventricular septal angle × 0.23) + (ventricular mass index × 16.3). In the validation cohort a strong correlation between mPAP and MR estimated mPAP was demonstrated (R(2) = 0.67). For detection of the presence of pulmonary hypertension the area under the receiver-operating characteristic (ROC) curve was 0.96 (0.92 to 1.00; p < 0.0001). CMR-estimated PVR reliably identified invasive PVR ≥3 Wood units (WU) with a high degree of accuracy, the area under the ROC curve was 0.94 (0.88 to 0.99; p < 0.0001). CMR imaging can accurately estimate mean pulmonary artery pressure in patients with suspected pulmonary hypertension and calculate PVR by estimating all major pulmonary hemodynamic metrics measured at RHC.

Correlation between the direction of the interventricular septum estimated with transmission computed tomography and the initial QRS vectors

A correlative study was performed to relate the interventricular septal angle (As degrees) evaluated by transmission computed tomography to the azimuth of initial QRS vectors in 52 patients. Patients were divided into five groups: RV volume overloading (RVO), RV pressure overloading (RSO), LV volume overloading (LVO), LV pressure overloading (LSO), and normal control with no cardiopulmonary disease. For measurement of As degrees, the leftward and forward directions were designated as zero and 90 degrees, respectively. The mean value of As degrees was significantly smaller in RVO (14.4 degrees) and RSO (41.1 degrees) than in normal controls (50.4 degrees) and in LVO (53.2 degrees). The mean value of the azimuth of the initial 12-msec instantaneous QRS vectors (H 12 degrees) was significantly smaller in RVO (80.5 degrees), RSO (81.7 degrees), and LSO (81.3 degrees) than in normal controls (113.8 degrees and in LVO (113.7 degrees). A significant linear correlation was shown between As degrees and H12 degrees in a combined group consisting of RVO, LVO, and normal controls (r = 0.70, p less than 0.001), and also in another combined group consisting of RSO, LSO, and normal controls (r = 0.52, p less than 0.01). It was concluded that the orientation of the interventricular septum was one of the major determinants of the direction of initial QRS vectors, especially in patients with ventricular volume overload or without cardiopulmonary disease.