Determinants and prognostic implications of the negative diastolic pulmonary pressure gradient in patients with pulmonary hypertension due to left heart disease

Pulmonary Hypertension Associated with Left Heart Disease

Pulmonary hypertension (PH) is a common complication of diseases affecting the left heart, mostly found in patients suffering from heart failure, with or without preserved left ventricular ejection fraction. Initially driven by a passive increase in left atrial pressure (postcapillary PH), several mechanisms may lead in a subset of patient to significant structural changes of the pulmonary vessels or a precapillary component. In addition, the right ventricle may be independently affected, which results in right ventricular to pulmonary artery uncoupling and right ventricular failure, all being associated with a worse outcome. The differential diagnosis of PH associated with left heart disease versus pulmonary arterial hypertension (PAH) is especially challenging in patients with cardiovascular comorbidities and/or heart failure with preserved ejection fraction (HFpEF). A stepwise approach to diagnosis is proposed, starting with a proper clinical multidimensional phenotyping to identify patients in whom hemodynamic confirmation is deemed necessary. Provocative testing (exercise testing, fluid loading, or simple leg raising) is useful in the cath laboratory to identify patients with abnormal response who are more likely to suffer from HFpEF. In contrast with group 1 PH, management of PH associated with left heart disease must focus on the treatment of the underlying condition. Some PAH-approved targets have been unsuccessfully tried in clinical studies in a heterogeneous group of patients, some even leading to an increase in adverse events. There is currently no approved therapy for PH associated with left heart disease.

Preoperative Pulmonary Artery-to-Aorta Diameter Ratio as a Predictor of Postoperative Severe Right Ventricular Failure and 1-Year Mortality After Left Ventricular Assist Device Implantation

OBJECTIVES

To evaluate the association of pulmonary artery diameter and pulmonary artery- to-aorta diameter ratio (PA/Ao) with right ventricular failure and mortality within 1 year after left ventricular assist device implantation.

DESIGN

This was a retrospective observational study between March 2013 and July 2019.

SETTING

The study was conducted at a single, quaternary-care academic center.

PARTICIPANTS

Adults (≥18 years old) receiving a durable left ventricular assist device (LVAD). Inclusion if (1) a chest computed tomography scan was performed within 30 days before the LVAD and (2) a right and left heart catheterization was completed within 30 days before the LVAD.

INTERVENTIONS

A left ventricular assist device was used for intervention.

MEASUREMENTS AND MAIN RESULTS

A total of 176 patients were included in this study. Median PA diameter and PA/Ao ratio were significantly greater in the severe right ventricular failure (RVF) group (p = 0.001, p < 0.001, respectively). Receiver operating characteristic analysis revealed PA/Ao and RVF as predictors for mortality (area under the curve = 0.725 and 0.933, respectively). Logistic regression analysis-predicted probability gave a PA/Ao ratio cutoff point of 1.04 (p < 0.001). Survival probability was significantly worse in patients with a PA/Ao ratio ≥1.04 (p = 0.005).

CONCLUSIONS

The PA/Ao ratio is an easily measurable noninvasive indicator that can predict RVF and 1-year mortality after LVAD implantation.

Animal models of pulmonary hypertension due to left heart disease

Pulmonary hypertension due to left heart disease (PH‐LHD) is regarded as the most prevalent form of pulmonary hypertension (PH). Indeed, PH is an independent risk factor and predicts adverse prognosis for patients with left heart disease (LHD). Clinically, there are no drugs or treatments that directly address PH‐LHD, and treatment of LHD alone will not also ameliorate PH. To target the underlying physiopathological alterations of PH‐LHD and to develop novel therapeutic approaches for this population, animal models that simulate the pathophysiology of PH‐LHD are required. There are several available models for PH‐LHD that have been successfully employed in rodents or large animals by artificially provoking an elevated pressure load on the left heart, which by transduction elicits an escalated pressure in pulmonary artery. In addition, metabolic derangement combined with aortic banding or vascular endothelial growth factor receptor antagonist is also currently applied to reproduce the phenotype of PH‐LHD. As of today, none of the animal models exactly recapitulates the condition of patients with PH‐LHD. Nevertheless, the selection of an appropriate animal model is essential in basic and translational studies of PH‐LHD. Therefore, this review will summarize the characteristics of each PH‐LHD animal model and discuss the advantages and limitations of the different models.

Pulmonary Hypertension in Left Heart Disease

Pulmonary hypertension is common in left heart disease and is related most commonly to passive back transmission of elevated left atrial pressures. Some patients, however, may develop pulmonary vascular remodeling superimposed on their left-sided heart disease. This review provides a contemporary appraisal of existing criteria to diagnose a precapillary component to pulmonary hypertension in left heart disease as well as discusses etiologies, management issues, and future directions.

[Differential Diagnosis of Pulmonary Hypertension Using the Example of Collagenosis-associated PAH in the Context of Chronic Lung and Left Heart Disease]

Pulmonary hypertension (PH) can be diagnosed in the context of connective tissue diseases (CTD) as well as in elderly patients with multiple comorbidities. A correct clinical differential diagnosis and classification is essential before adequate therapeutic decisions can be made. Differential diagnosis of PH in CTD comprises associated pulmonary arterial hypertension (APAH), group 2 or 3 PH (PH arising from left heart or chronic lung disease), chronic thromboembolic PH (PH) and group 5 (e. g. in the context of terminal renal insufficiency). This is also true of elderly patients in whom the decision has to be made if the increasing number of coincident diseases lead to PH or have to be interpreted as comorbidities. In this manuscript, the differential diagnosis of PH is elucidated, focusing on CTD, in the context of left heart disease and chronic lung disease. Furthermore, criteria are presented facilitating an objective approach in this context.

Critical appraisal of the instantaneous end-diastolic pulmonary arterial wedge pressures

Aims

A substantial shift in the field of pulmonary hypertension (PH) is ongoing, as the previous practice of mean pulmonary arterial wedge pressure (PAWP_M) is no longer supported. Instead, aiming for a better estimate of end‐diastolic pressures (EDP), instantaneous PAWP at mid‐A‐wave (PAWP_mid‐A) or, in the absence of an A‐wave, at 130–160 ms following QRS onset has recently been recommended. Electrocardiogram‐gated PAWP (PAWP_QRS) has also been proposed. The quantitative differences as well as the diagnostic and prognostic utility of these novel PAWP measurements have not been evaluated. We set out to address these issues.

Methods and results

Pressure tracings of 141 patients with PH due to left heart disease (PH‐LHD) and 43 with primary pulmonary arterial hypertension (PAH) were analysed. PAWP was measured as follows: (i) mean pressure (PAWP_M); (ii) per the latest consensus approach [PAWP_mid‐A, or in atrial fibrillation 130, 140, 150, and 160 ms following QRS onset (PAWP_130–160)]; (iii) at QRS onset (PAWP_QRS); and (iv) Z‐point (PAWP_Z). For each PAWP, the corresponding pulmonary vascular resistance (PVR) and diastolic pressure gradient were calculated. The cohort comprised 45% female. Mean age was 66 ± 15. PAWP_mid‐A was in good agreement with PAWP_Z (17.3 [14.5 to 21.2] vs. 17.6 [14.2 to 21.6] mmHg, P = 0.63), whereas PAWP_QRS provided significantly lower values (15.3 [12.5 to 19.2] mmHg, P < 0.001). In atrial fibrillation, PAWP₁₃₀ and PAWP_QRS yielded the optimal temporal and quantitative analyses of EDPs. The ability to differentiate PAH from PH‐LHD was similar for the various PAWP measurements [PAWP_M: area under the curve (AUC) 0.98, confidence interval (CI) 0.96–0.99; PAWP_mid‐A/130: AUC 0.94, CI 0.91–0.98; PAWP_QRS: AUC 0.96, CI 0.94–0.99, P < 0.001 for all]. PVR based on instantaneous PAWP measurements failed to provide superior prognostic information in PH‐LHD as compared with conventional PVR.

Conclusions

Although instantaneous PAWP measurement might better represent EDP, they nevertheless fail to yield incremental diagnostic or prognostic information in PH‐LHD as compared with conventional measurements.

The Differential Impact of the Left Atrial Pressure Components on Pulmonary Arterial Compliance-Resistance Relationship in Heart Failure

BACKGROUND

An increase in the pulmonary capillary wedge pressure (PAWP) has been shown to impact on the inherent relationship between the pulmonary arterial compliance (PAC) and pulmonary vascular resistance (PVR), thus augmenting the pulsatile relative to the resistive load of the right ventricle. However, the PAWP comprises the integration of both the steady and the pulsatile pressure components. We sought to address the differential impact of the these distinct PAWP components on the PAC-PVR relationship in a cohort of patients with heart failure.

METHODS AND RESULTS

The study population consisted of 192 patients with hemodynamic findings diagnostic for heart failure. Off-line analysis was performed using the MATLAB software. The steady and pulsatile PAWP components were calculated as mid-A pressure and mean pressure during the V-wave oscillation, respectively. The PAC and PVR were hyperbolically and inversely associated and the subgroup of patients with PAWP above the median (>18 mm Hg) displayed a significant left and downward shift of the curve fit (P < .001). The shift in the PAC-PVR fit between patients with higher versus low steady PAWP was not significant (P = .43). In contrast, there was a significant downward and leftward shift of the PVR-PAC curve fit for the subgroup with a higher pulsatile PAWP (P < .001). Furthermore, only the pulsatile PAWP was significantly associated with the time-constant of the pulmonary circulation, assessed as the PAC × PVR product (P < .001).

CONCLUSIONS

In patients with heart failure, the pulsatile rather than the steady PAWP component stands for the previously documented shift of the PAC-PVR relationship occurring at an elevated PAWP.

Optimizing diastolic pressure gradient assessment

Aims

The diastolic pressure gradient (DPG) has been proposed as a marker pulmonary vascular disease in the setting of left heart failure (HF). However, its diagnostic utility is compromised by the high prevalence of physiologically incompatible negative values (DPG_NEG) and the contradictory evidence on its prognostic value. Pressure pulsatility impacts on DPG measurements, thus conceivably, pulmonary artery wedge pressure (PAWP) measurements insusceptible to the oscillatory effect of the V-wave might yield a more reliable DPG assessment. We set out to investigate how the instantaneous PAWP at the trough of the Y-descent (PAWP_Y) influences the prevalence of DPG_NEG and the prognostic value of the resultant DPG_Y.

Methods

Hundred and fifty-three consecutive HF patients referred for right heart catheterisation were enrolled prospectively. DPG, as currently recommended, was calculated. Subsequently, PAWP_Y was measured and the corresponding DPG_Y was calculated.

Results

DPG_Y yielded higher values (median, IQR: 3.2, 0.6–5.7 mmHg) than DPG (median, IQR: 0.9, − 1.7–3.8 mmHg); p < 0.001. Conventional DPG was negative in 45% of the patients whereas DPG_Y in only 15%. During follow-up (22 ± 14 months) 58 patients have undergone heart-transplantation or died. The predictive ability of DPG_Y ≥ 6 mmHg for the above defined end-point events was significant [HR 2.1; p = 0.007] and independent of resting mean pulmonary artery pressure (PAP_M). In contrast, conventional DPG did not comprise significant prognostic value following adjustment for PAP_M.

Conclusion

Instantaneous pressures at the trough of Y-descent yield significantly fewer DPG_NEG than conventional DPG and entail superior prognostic value in HF patients with and without PH.

Graphic abstract

Electronic supplementary material

The online version of this article (10.1007/s00392-020-01641-w) contains supplementary material, which is available to authorized users.

Rationale and design of the optical coherence tomography observation of pulmonary ultra-structural changes in heart failure (OCTOPUS-CHF) study

BACKGROUND

The assessment of vascular remodeling using optical coherence tomography (OCT) has been previously described in some types of pulmonary hypertension. However, evidence about its feasibility and clinical utility for evaluation of pulmonary arterial vasculopathy in advanced heart failure (HF) is scarce. Optical Coherence Tomography Observation of Pulmonary Ultra-Structural Changes in Heart Failure (OCTOPUS-CHF) study is designed to study the correlation between OCT-morphometric parameters and hemodynamic data measured or derived from right heart catheterization (RHC).

METHODS

OCTOPUS-CHF is an observational, prospective, multicentre study aiming to recruit 100 patients with advanced HF referred for heart transplantation (HTx) evaluation. As part of such evaluation, all patients will undergo RHC in order to rule out severe pulmonary hypertension. After RHC, a Dragonfly™ OPTIS™ imaging catheter will be used to perform OCT evaluation of a right-lower-lobe pulmonary artery with a luminal diameter ≤ 5 mm. The primary objective is to study the correlation of OCT parameters with hemodynamic RHC data. The secondary objective is to determine if OCT parameters improve prognostic stratification.

CONCLUSIONS

The OCTOPUS-CHF study will investigate the feasibility and clinical utility of pulmonary arterial vasculopathy evaluation with OCT in advanced HF patients and its correlation with hemodynamic RHC data. The ability of OCT-morphometric parameters to improve prognostic stratification will also be tested.

Highlights in heart failure

Heart failure (HF) remains a major cause of mortality, morbidity, and poor quality of life. It is an area of active research. This article is aimed to give an update on recent advances in all aspects of this syndrome. Major changes occurred in drug treatment of HF with reduced ejection fraction (HFrEF). Sacubitril/valsartan is indicated as a substitute to ACEi/ARBs after PARADIGM-HF (hazard ratio [HR], 0.80; 95% confidence interval [CI], 0.73 to 0.87 for sacubitril/valsartan vs. enalapril for the primary endpoint and Wei, Lin and Weissfeld HR 0.79, 95% CI 0.71-0.89 for recurrent events). Its initiation was then shown as safe and potentially useful in recent studies in patients hospitalized for acute HF. More recently, dapagliflozin and prevention of adverse-outcomes in DAPA-HF trial showed the beneficial effects of the sodium-glucose transporter type 2 inhibitor dapaglifozin vs. placebo, added to optimal standard therapy [HR, 0.74; 95% CI, 0.65 to 0.85;0.74; 95% CI, 0.65 to 0.85 for the primary endpoint]. Trials with other SGLT 2 inhibitors and in other patients, such as those with HF with preserved ejection fraction (HFpEF) or with recent decompensation, are ongoing. Multiple studies showed the unfavourable prognostic significance of abnormalities in serum potassium levels. Potassium lowering agents may allow initiation and titration of mineralocorticoid antagonists in a larger proportion of patients. Meta-analyses suggest better outcomes with ferric carboxymaltose in patients with iron deficiency. Drugs effective in HFrEF may be useful also in HF with mid-range ejection fraction. Better diagnosis and phenotype characterization seem warranted in HF with preserved ejection fraction. These and other burning aspects of HF research are summarized and reviewed in this article.

Association Between Hemodynamic Markers of Pulmonary Hypertension and Outcomes in Heart Failure With Preserved Ejection Fraction

Importance

Heart failure with preserved ejection fraction (HFpEF) is highly prevalent, yet there are no specific therapies, possibly due to phenotypic heterogeneity. The development of pulmonary hypertension (PH) in patients with HFpEF is considered a high-risk phenotype in need of targeted therapies, but there have been limited hemodynamic and outcomes data.

Objective

To identify the hemodynamic characteristics and outcomes of PH-HFpEF.

Design, Setting, and Participants

Cohort study of participants who had a right heart catheterization from January 2005 to September 2012 (median [interquartile range] follow-up time, 1578 [554-2513] days) were analyzed. Hemodynamic catheterization data was linked to the clinical data repository of all inpatient and outpatient encounters across a health system. Single tertiary referral center for heart failure and PH within a large health care network using a common clinical data repository was studied. There were 19 262 procedures in 10 023 participants.

Exposures

Participants were classified as having no PH, precapillary PH, or PH in the setting of left heart disease (reduced or preserved ejection fraction). Pulmonary hypertension associated with HFpEF was defined as mean pulmonary artery pressure of 25 mm Hg or more, pulmonary artery wedge pressure of 15 mm Hg or more, and left ventricular ejection fraction of 45% or more. Pulmonary hypertension severity was quantified by the hemodynamic parameters transpulmonary gradient, pulmonary vascular resistance, and diastolic pulmonary gradient.

Main Outcomes and Measures

The primary outcome was time to all-cause mortality. Secondary outcomes were time to acute hospitalization and cardiovascular hospitalization.

Results

The mean (SD) of all study individuals was 65 (38) years. Of 10 023 individuals, 2587 (25.8%) had PH-HFpEF. Mortality was 23.6% at 1 year and 48.2% at 5 years. Cardiac hospitalizations occurred in 28.1% at 1 year and 47.4% at 5 years. The frequency of precapillary PH using clinically defined cut-offs for transpulmonary gradient (>12 mm Hg), pulmonary vascular resistance (3 Woods units), and diastolic pulmonary gradient (≥7 mm Hg) were 12.6%, 8.8%, and 3.5%, respectively. Transpulmonary gradient, pulmonary vascular resistance, and diastolic pressure gradient were predictive of mortality and cardiac hospitalizations.

Conclusions and Relevance

In a large cohort referred for invasive hemodynamic assessment, PH-HFpEF was common. Transpulmonary gradient, pulmonary vascular resistance, and diastolic pulmonary gradient are all associated with mortality and cardiac hospitalizations.

Impact of the New Pulmonary Hypertension Definition on Heart Transplant Outcomes: Expanding the Hemodynamic Risk Profile

BACKGROUND

At the recent 6th World Symposium on Pulmonary Hypertension (PH), the definition of PH was redefined to include lower pulmonary artery pressures in the setting of elevated pulmonary vascular resistance (PVR). However, the relevance of this change to subjects with PH due to left-heart disease as well as the preoperative assessment of heart transplant (HT) recipients is unknown.

METHODS

The United Network for Organ Sharing database was queried to identify adult recipients who underwent primary HT from 1996 to 2015. Recipients were subdivided into those with mean pulmonary artery pressure (mPAP) < 25 mm Hg and ≥ 25 mm Hg. Exploratory univariable analysis was undertaken to identify candidate risk factors associated with 30-day and 1-year survival (conditional on 30-day survival) in recipients with mPAP < 25 mm Hg, and subsequently, parsimonious multivariable Cox proportional hazards models were constructed to assess the independent association with PVR.

RESULTS

Over the study period, 32,465 patients underwent HT, including 12,257 (38%) with mPAP < 25 mm Hg. The median age was 55 years (interquartile range, 47-62) and the median PVR was 1.5 Wood units (WU) (interquartile range, 1-2.2) in recipients with mPAP < 25 mm Hg. After controlling for confounders, PVR was independently associated with increased risk for 30-day mortality (hazard ratio, 1.16; 95% CI, 1.05-1.27; P < .01), but not conditional 1-year mortality (hazard ratio, 1.03; 95% CI, 0.94-1.12; P = .55). PVR ≥ 3 WU was associated with an absolute 1.9% increase in 30-day mortality in those with mPAP < 25 mm Hg, a similar risk to recipients with PVR ≥ 3 WU and mPAP ≥ 25 mm Hg.

CONCLUSIONS

Elevated PVR remains associated with a significant increase in the hazard for 30-day mortality after cardiac transplantation, even in the setting of lower pulmonary artery pressures. These data support the validity of the new definition of pulmonary hypertension.

Pulmonary hypertension due to left heart disease

Pulmonary hypertension (PH) is frequent in left heart disease (LHD), as a consequence of the underlying condition. Significant advances have occurred over the past 5 years since the 5th World Symposium on Pulmonary Hypertension in 2013, leading to a better understanding of PH-LHD, challenges and gaps in evidence. PH in heart failure with preserved ejection fraction represents the most complex situation, as it may be misdiagnosed with group 1 PH. Based on the latest evidence, we propose a new haemodynamic definition for PH due to LHD and a three-step pragmatic approach to differential diagnosis. This includes the identification of a specific “left heart” phenotype and a non-invasive probability of PH-LHD. Invasive confirmation of PH-LHD is based on the accurate measurement of pulmonary arterial wedge pressure and, in patients with high probability, provocative testing to clarify the diagnosis. Finally, recent clinical trials did not demonstrate a benefit in treating PH due to LHD with pulmonary arterial hypertension-approved therapies.

State of the art and research perspectives in pulmonary hypertension due to left heart disease including diagnostic and treatment insightshttp://ow.ly/vr0I30md6KC

Insights into the pulmonary vascular complications of heart failure with preserved ejection fraction

Pulmonary hypertension in the setting of heart failure with preserved ejection fraction (PH-HFpEF) is a growing public health problem that is increasing in prevalence. While PH-HFpEF is defined by a high mean pulmonary artery pressure, high left ventricular end-diastolic pressure and a normal ejection fraction, some HFpEF patients develop PH in the presence of pulmonary vascular remodelling with a high transpulmonary pressure gradient or pulmonary vascular resistance. Ageing, increased left atrial pressure and stiffness, mitral regurgitation, as well as features of metabolic syndrome, which include obesity, diabetes and hypertension, are recognized as risk factors for PH-HFpEF. Qualitative studies have documented that patients with PH-HFpEF develop more severe symptoms than those with HFpEF and are associated with more significant exercise intolerance, frequent hospitalizations, right heart failure and reduced survival. Currently, there are no effective therapies for PH-HFpEF, although a number of candidate drugs are being evaluated, including soluble guanylate cyclase stimulators, phosphodiesterase type 5 inhibitors, sodium nitrite and endothelin receptor antagonists. In this review we attempt to provide an updated overview of recent findings pertaining to the pulmonary vascular complications in HFpEF in terms of clinical definitions, epidemiology and pathophysiology. Mechanisms leading to pulmonary vascular remodelling in HFpEF, a summary of pre-clinical models of HFpEF and PH-HFpEF, and new candidate therapeutic strategies for the treatment of PH-HFpEF are summarized.

Haemodynamic mechanisms and long-term prognostic impact of pulmonary hypertension in patients with severe aortic stenosis undergoing valve replacement

AIMS

We aimed to investigate the prevalence, detailed invasive haemodynamics, and prognostic impact of pulmonary hypertension (PH) in severe aortic stenosis (AS).

METHODS AND RESULTS

We studied 503 patients (mean age 74 ± 10 years) with severe AS (indexed aortic valve area 0.4 ± 0.1 cm² /m² , left ventricular ejection fraction 57 ± 12%) undergoing left and right heart catheterization prior to aortic valve replacement. Median follow-up was 3.7 (interquartile range 2.6-5.4) years. Baseline PH (mean pulmonary artery pressure ≥ 25 mmHg) was found in 239 (48%) patients: 31 patients had pre-capillary PH [mean pulmonary artery wedge pressure (mPAWP) ≤ 15 mmHg], 144 had isolated post-capillary PH [IpcPH; mPAWP > 15 mmHg, pulmonary vascular resistance (PVR) ≤ 3 Wood units (WU)], and 64 had combined pre- and post-capillary PH (CpcPH; mPAWP > 15 mmHg, PVR > 3 WU). Patients with CpcPH had higher mortality than those with IpcPH, pre-capillary PH, and without PH. In the multivariate analysis, CpcPH remained an independent predictor of death (hazard ratio 4.39, 95% confidence interval 2.40-8.03; P < 0.001). Patients with CpcPH had higher mPAWP (26 ± 7 vs. 22 ± 5 mmHg) and lower pulmonary arterial capacitance (1.5 ± 0.6 vs. 2.9 ± 1.2 mL/mmHg) than IpcPH patients but similar left ventricular end-diastolic pressure (LVEDP; 25 ± 7 vs. 25 ± 7 mmHg). A smaller LVEDP-mPAWP difference was related to larger left atrial size, atrial fibrillation, and more severe mitral regurgitation.

CONCLUSIONS

In patients with severe AS, PH is common but underlying mechanisms differ. Patients with CpcPH have higher mPAWP, lower pulmonary arterial capacitance, and worse survival than all other groups. Left atrial dysfunction and mitral regurgitation seem to be drivers of high mPAWP in CpcPH.

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

Purpose To 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 Methods In 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. Results A 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). Conclusion The 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.

Clinical phenotypes and outcomes of pulmonary hypertension due to left heart disease: Role of the pre-capillary component

Background

In pulmonary hypertension (PH), both wedge pressure elevation (PAWP) and a precapillary component may affect right ventricular (RV) afterload. These changes may contribute to RV failure and prognosis. We aimed at describing the different haemodynamic phenotypes of patients with PH due to left heart disease (LHD) and at characterizing the impact of pulmonary haemodynamics on RV function and outcome PH-LHD.

Methods

Patients with PH-LHD were compared with treatment-naïve idiopathic/heritable pulmonary arterial hypertension (PAH, n = 35). PH-LHD patients were subdivided in Isolated post-capillary PH (IpcPH: diastolic pressure gradient, DPG<7 mmHg and pulmonary vascular resistance, PVR≤3 WU, n = 37), Combined post- and pre-capillary PH (CpcPH: DPG≥7 mmHg and PVR>3 WU, n = 27), and “intermediate” PH-LHD (either DPG <7 mmHg or PVR ≤3 WU, n = 29).

Results

Despite similar PAWP and cardiac index, haemodynamic severity and prevalence of RV dysfunction increased from IpcPH, to “intermediate” and CpcPH. PVR and DPG (but not compliance, Ca) were linearly correlated with RV dysfunction. CpcPH had worse prognosis (p<0.05) than IpcPH and PAH, but similar to “intermediate” patients. Only NTproBNP and Ca independently predicted survival in PH-LHD.

Conclusions

In PH-LHD, haemodynamic characterization according to DPG and PVR provides important information on disease severity, predisposition to RV failure and prognosis. Patients presenting the CpcPH phenotype appear to have haemodynamic profile closer to PAH but with worse prognosis. In PH-LHD, Ca and NTproBNP were independent predictors of survival.

Diastolic pressure indices offer a novel approach to predicting risk of graft loss after pediatric heart transplant

PH is a risk factor for GL after HTx. However, traditional parameters are not reliable predictors of risk in children. We hypothesized that DPI (dPAP and DPG) are predictive of GL in pediatric HTx recipients. The UNOS/SRTR database was reviewed to identify pediatric HTx recipients (age <18 years) between 1994 and 2013. Recipients with pretransplant hemodynamic data were grouped by diagnosis (CMP or CHD), and the groups were analyzed separately. Bivariate Cox regression analysis examined the association between hemodynamic variables and GL. DPI showed the strongest association with early GL in recipients with CMP (dPAP: HR = 1.25 [1.09-1.42]; DPG: 1.24 [1.11-1.38]). Among CHD recipients, DPI were associated with early GL in those with preexisting PH (dPAP: HR = 1.16 [1.01-1.33]; DPG: HR = 1.10 [1.00-1.21]). No cutoff values for "high-risk" DPI were identified, but a continuous relationship between higher DPI and risk of early GL was observed. DPI are associated with early GL in select pediatric HTx recipients. Our findings suggest that DPI should be considered as part of routine hemodynamic assessment for pediatric HTx candidates.

Haemodynamic effects of an acute vasodilator challenge in heart failure patients with reduced ejection fraction and different forms of post-capillary pulmonary hypertension

AIMS

The most recent European guidelines have proposed new definitions of pulmonary hypertension (PH) in left heart disease, to better approach the characteristics required to reflect the presence of pulmonary vascular disease. The purpose of this study was to assess whether different haemodynamic definitions of post-capillary PH imply a different reversibility of PH in response to acute vasodilator administration in heart failure patients with reduced ejection fraction and PH (HFrEF-PH).

METHODS AND RESULTS

Right heart catheterization and reversibility testing was performed in 156 HFrEF-PH patients. Patients were classified as combined post-capillary and pre-capillary pulmonary hypertension (Cpc-PH) vs. isolated post-capillary pulmonary hypertension (Ipc-PH) and on the basis of diastolic pulmonary gradient (DPG) ≥ 7 vs. < 7 mmHg or of transpulmonary gradient (TPG) >12 vs. ≤12 mmHg. After vasodilator administration, Cpc-PH patients showed a greater per cent improvement in pulmonary vascular resistance (PVR), DPG and TPG as compared with Ipc-PH patients (all P_int < 0.001); only pulmonary compliance (PCa) improved less in Cpc-PH than in Ipc-PH patients (P_int = 0.007). However, despite vasodilatation, Cpc-PH patients remained in an unfavourable portion of the inverse hyperbolic relationship between PVR and PCa. The number of patients in whom PVR was reduced below 2.5 wood units was similar in Cpc-PH, DPG ≥7 mmHg and TPG >12 mmHg groups (28.3, 26.7 and 18.9%, respectively).

CONCLUSION

Although substantial improvements in PVR, DPG and TPG were observed in Cpc-PH patients after acute vasodilator administration, this response was associated with persistent abnormalities in the PVR vs. PCa relationship. The link between baseline right heart haemodynamics and pulmonary vascular disease remains elusive.

Pulmonary hemodynamics in heart failure patients with reduced or preserved ejection fraction and pulmonary hypertension: Similarities and disparities

OBJECTIVE

The current understanding of pulmonary hypertension (PH) due to left ventricular diseases does not distinguish heart failure (HF) with reduced ejection fraction (HFrEF) from HF and preserved ejection fraction (HFpEF), in terms of pulmonary hemodynamics. The value of pulmonary vascular compliance (PCa) and diastolic pulmonary gradient (DPG) as predictors of survival in either HF syndrome is controversial. The aims of our study were to compare the pulmonary hemodynamics in the two HF phenotypes, given similar values of pulmonary artery wedge pressure (PAWP), and to evaluate the impact of PCa and DPG on survival.

METHODS

We retrospectively reviewed the charts of 168 PH-HFrEF and 86 PH-HFpEF patients. The independent association of PCa and DPG with prognosis was assessed by means of a Cox proportional hazard model. All cause survival was analyzed over an average follow-up period of 50 months.

RESULTS

PH-HFpEF patients had a significantly higher DPG than PH-HFrEF patients (6.1±7.1 vs 1.8±4.5 mmHg, adjusted P=.025). PCa was similar in PH-HFpEF and PH-HFrEF. PCa was a significant predictor of survival, according to previously described preset cutoffs (2.15 mL/mmHg in HFrEF and 1.1 mL/mmHg in HFpEF) and based on a continuous scale; whereas DPG had no impact on survival in both patients groups.

CONCLUSION

Our findings suggest that for similar levels of PAWP, pulmonary circulation may be stiffer in patients with HFpEF-PH than patients with HFrEF-PH, leading to higher DPGs. Nonetheless, PCa rather than DPG emerged as the stronger predictor of survival in both left-sided PH phenotypes.

Hemodynamic Phenotyping of Pulmonary Hypertension in Left Heart Failure

Increased pulmonary venous pressure secondary to left heart disease is the most common cause of pulmonary hypertension (PH). The diagnosis of PH due to left heart disease relies on a clinical probability assessment followed by the invasive measurements of a mean pulmonary artery pressure (PAP) ≥25 mm Hg and mean wedged PAP (PAWP) >15 mm Hg. A combination of mean PAP and mean PAWP defines postcapillary PH. Postcapillary PH is generally associated with a diastolic pulmonary pressure gradient (diastolic PAP minus mean PAWP) <7 mm Hg, a transpulmonary pressure gradient (mean PAP minus mean PAWP) <12 mm Hg, and pulmonary vascular resistance ≤3 Wood units (WU). This combination of criteria defines isolated postcapillary PH. Postcapillary PH with elevated vascular gradients and pulmonary vascular resistance defines combined post- and precapillary PH (Cpc-PH). Postcapillary PH is associated with a decreased survival in proportion to increased pulmonary vascular gradients, decreased pulmonary arterial compliance, and reduced right ventricular function. The Cpc-PH subcategory occurs in 12% to 13% of patients with PH due to left heart disease. Patients with Cpc-PH have severe PH, with higher diastolic pulmonary pressure gradient, transpulmonary pressure gradient, and pulmonary vascular resistance and more pronounced ventilatory responses to exercise, lower pulmonary arterial compliance, depressed right ventricular ejection fraction, and shorter life expectancy than isolated postcapillary PH. Cpc-PH bears similarities to pulmonary arterial hypertension. Whether Cpc-PH is amenable to therapies targeting the pulmonary circulation remains to be tested by properly designed randomized controlled trials.

Atrial fibrillation modifies the association between pulmonary artery wedge pressure and left ventricular end-diastolic pressure

AIMS

During right heart catheterization, pulmonary artery wedge pressure (PAWP) is often assumed to reflect left ventricular filling pressure. We sought to determine the impact of atrial fibrillation (AF) on the relationship between PAWP and left ventricular filling pressure, as measured by left ventricular end-diastolic pressure (LVEDP).

METHODS AND RESULTS

We performed simultaneous left and right heart catheterization in 123 patients (mean age 69 years, 28% with AF) referred for suspicion of pulmonary hypertension (PH). The correlation between PAWP and LVEDP was moderate (R² = 0.42). The relationship between PAWP and LVEDP was modified by heart rhythm (P for interaction <0.01). In sinus rhythm, PAWP underestimated LVEDP (Bland-Altman mean difference: -2.96 mmHg, limits of agreement 6.6 to -12.5; R²  = 0.54), whereas in AF, PAWP overestimated LVEDP (Bland-Altman mean difference: 4.76 mmHg; limits of agreement: 12.2 to -3.3; R² = 0.58). These differences impacted the differentiation between pre- and post-capillary PH, dependent on the use of either PAWP or LVEDP. In AF, post-capillary PH based on PAWP would have been classified as pre-capillary PH in 35% of patients if based on LVEDP. The opposite is true for sinus rhythm where 31% of pre-capillary PH based on PAWP would have been classified as post-capillary PH if based on LVEDP.

CONCLUSION

The relationship between PAWP and LVEDP varies by heart rhythm, with PAWP being higher than LVEDP among AF patients and lower than LVEDP among patients in sinus rhythm. Rhythm status and influences on the PAWP-LVEDP relationship should be considered when distinguishing between pre-capillary and post-capillary PH.

Diastolic Pressure Difference to Classify Pulmonary Hypertension in the Assessment of Heart Transplant Candidates

BACKGROUND

The diastolic pressure difference (DPD) is recommended to differentiate between isolated postcapillary and combined pre-/postcapillary pulmonary hypertension (Cpc-PH) in left heart disease (PH-LHD). However, in usual practice, negative DPD values are commonly calculated, potentially related to the use of mean pulmonary artery wedge pressure (PAWP). We used the ECG to gate late-diastolic PAWP measurements. We examined the method's impact on calculated DPD, PH-LHD subclassification, hemodynamic profiles, and mortality.

METHODS AND RESULTS

We studied patients with advanced heart failure undergoing right heart catheterization to assess cardiac transplantation candidacy (N=141). Pressure tracings were analyzed offline over 8 to 10 beat intervals. Diastolic pulmonary artery pressure and mean PAWP were measured to calculate the DPD as per usual practice (diastolic pulmonary artery pressure-mean PAWP). Within the same intervals, PAWP was measured gated to the ECG QRS complex to calculate the QRS-gated DPD (diastolic pulmonary artery pressure-QRS-gated PAWP). Outcomes occurring within 1 year were collected retrospectively from chart review. Overall, 72 of 141 cases demonstrated PH-LHD. Within PH-LHD, the QRS-gated DPD yielded higher calculated DPD values (3 [-1 to 6] versus 0 [-4 to 3] mm Hg; P<0.01) and a greater proportion of Cpc-PH (24% versus 8%; P<0.01) versus the usual practice DPD. Cases reclassified as Cpc-PH based on QRS-gated DPD demonstrated higher pulmonary arterial pressures versus isolated postcapillary pulmonary hypertension (P<0.05). One-year mortality was similar between PH-LHD groups.

CONCLUSIONS

The DPD calculated in usual practice is underestimated in PH-LHD, which may classify Cpc-PH patients as isolated postcapillary pulmonary hypertension. The QRS-gated DPD reclassifies a subset of PH-LHD patients from isolated postcapillary pulmonary hypertension to Cpc-PH, which is characterized by an adverse hemodynamic profile.

Management of pulmonary hypertension from left heart disease in candidates for orthotopic heart transplantation

Pulmonary hypertension in left heart disease (PH-LHD) commonly complicates prolonged heart failure (HF). When advanced, the PH becomes fixed or out of proportion and is associated with increased morbidity and mortality in patients undergoing orthotopic heart transplant (OHT). To date, the only recommended treatment of out of proportion PH is the treatment of the underlying HF by reducing the pulmonary capillary wedge pressure (PCWP) with medications and often along with use of mechanical circulatory support. Medical therapies typically used in the treatment of World Health Organization (WHO) group 1 pulmonary arterial hypertension (PAH) have been employed off-label in the setting of PH-LHD with varying efficacy and often negative outcomes. We will discuss the current standard of care including treating HF and use of mechanical circulatory support. In addition, we will review the studies published to date assessing the efficacy and safety of PAH medications in patients with PH-LHD being considered for OHT.

Pulmonary hypertension due to left heart disease causes intrapulmonary venous arterialization in rats

OBJECTIVE

A rat model of left atrial stenosis-associated pulmonary hypertension due to left heart diseases was prepared to elucidate its mechanism.

METHODS

Five-week-old Sprague-Dawley rats were randomly divided into 2 groups: left atrial stenosis and sham-operated control. Echocardiography was performed 2, 4, 6, and 10 weeks after surgery, and cardiac catheterization and organ excision were subsequently performed at 10 weeks after surgery.

RESULTS

Left ventricular inflow velocity, measured by echocardiography, significantly increased in the left atrial stenosis group compared with that in the sham-operated control group (2.2 m/s, interquartile range [IQR], 1.9-2.2 and 1.1 m/s, IQR, 1.1-1.2, P < .01), and the right ventricular pressure-to-left ventricular systolic pressure ratio significantly increased in the left atrial stenosis group compared with the sham-operated control group (0.52, IQR, 0.54-0.60 and 0.22, IQR, 0.15-0.27, P < .01). The right ventricular weight divided by body weight was significantly greater in the left atrial stenosis group than in the sham-operated control group (0.54 mg/g, IQR, 0.50-0.59 and 0.39 mg/g, IQR, 0.38-0.43, P < .01). Histologic examination revealed medial hypertrophy of the pulmonary vein was thickened by 1.6 times in the left atrial stenosis group compared with the sham-operated control group. DNA microarray analysis and real-time polymerase chain reaction revealed that transforming growth factor-β mRNA was significantly elevated in the left atrial stenosis group. The protein levels of transforming growth factor-β and endothelin-1 were increased in the lung of the left atrial stenosis group by Western blot analyses.

CONCLUSIONS

We successfully established a novel, feasible rat model of pulmonary hypertension due to left heart diseases by generating left atrial stenosis. Although pulmonary hypertension was moderate, the pulmonary hypertension due to left heart diseases model rats demonstrated characteristic intrapulmonary venous arterialization and should be used to further investigate the mechanism of pulmonary hypertension due to left heart diseases.