Characterization of Pulmonary Hypertension in Heart Failure Using the Diastolic Pressure Gradient

Pulmonary Hypertension in Left Heart Diseases: Pathophysiology, Hemodynamic Assessment and Therapeutic Management

Pulmonary hypertension (PH) associated with left heart diseases (PH-LHD), also termed group 2 PH, represents the most common form of PH. It develops through the passive backward transmission of elevated left heart pressures in the setting of heart failure, either with preserved (HFpEF) or reduced (HFrEF) ejection fraction, which increases the pulsatile afterload of the right ventricle (RV) by reducing pulmonary artery (PA) compliance. In a subset of patients, progressive remodeling of the pulmonary circulation resulted in a pre-capillary phenotype of PH, with elevated pulmonary vascular resistance (PVR) further increasing the RV afterload, eventually leading to RV-PA uncoupling and RV failure. The primary therapeutic objective in PH-LHD is to reduce left-sided pressures through the appropriate use of diuretics and guideline-directed medical therapies for heart failure. When pulmonary vascular remodeling is established, targeted therapies aiming to reduce PVR are theoretically appealing. So far, such targeted therapies have mostly failed to show significant positive effects in patients with PH-LHD, in contrast to their proven efficacy in other forms of pre-capillary PH. Whether such therapies may benefit some specific subgroups of patients (HFrEF, HFpEF) with specific hemodynamic phenotypes (post- or pre-capillary PH) and various degrees of RV dysfunction still needs to be addressed.

Left atrial enlargement is associated with pulmonary vascular disease in heart failure with preserved ejection fraction

AIMS

Elevated left atrial (LA) pressure is a pathophysiologic hallmark of heart failure with preserved ejection fraction (HFpEF). Chronically elevated LA pressure leads to LA enlargement, which may impair LA function and increase pulmonary pressures. We sought to evaluate the relationship between LA volume and pulmonary arterial haemodynamics in patients with HFpEF.

METHODS AND RESULTS

Data from 85 patients (aged 69 ± 8 years) who underwent exercise right heart catheterization and echocardiography were retrospectively analysed. All had symptoms of heart failure, left ventricular ejection fraction ≥50% and haemodynamic features of HFpEF. Patients were divided into LA volume index-based tertiles (≤34 ml/m2 , >34 to ≤45 ml/m2 , >45 ml/m2 ). A subgroup analysis was performed in patients with recorded LA global reservoir strain (n = 60), with reduced strain defined as ≤24%. Age, sex, body surface area and left ventricular ejection fraction were similar between volume groups. LA volume was associated with blunted increases in cardiac output with exercise (padjusted  <0.001), higher resting mean pulmonary artery pressure (padjusted  = 0.003), with similar wedge pressure (padjusted  = 1). Pulmonary vascular resistance (PVR) increased with increasing LA volume (padjusted  <0.001). Larger LA volumes featured reduced LA strain (padjusted  <0.001), with reduced strain associated with reduced PVR-compliance time (0.34 [0.28-0.40] vs. 0.38 [0.33-0.43], p = 0.03).

CONCLUSION

Increasing LA volume may be associated with more advanced pulmonary vascular disease in HFpEF, featuring higher PVR and pulmonary pressures. Reduced LA function, worse at increasing LA volumes, is associated with a disrupted PVR-compliance relationship, further augmenting impaired pulmonary haemodynamics.

The definition of pulmonary hypertension: history, practical implications and current controversies

The definition of pulmonary hypertension (PH) is based on a growing body of evidence and represents the result of ongoing discussions within the PH community over the past 50 years. In 2018, the most recent World Symposium on Pulmonary Hypertension introduced significant changes in the definition of PH by lowering the mean pulmonary arterial pressure threshold to >20 mmHg and (re)introducing the pulmonary vascular resistance ≥3 WU cut-off for all forms of pre-capillary PH. These changes and their potential clinical impact have been the subject of lively discussions in the community and some important questions and controversies have been identified.

In this review we aim to present the development of the definition of PH over the past decades and discuss the main arguments that led to relevant modifications. In addition, we address the practical implications of the most recent changes and controversies that still exist.

The definitions of PH and PAH reflect the upper limit of normal haemodynamic values, their prognostic relevance and practical considerations. With appropriate clinical context they represent the cornerstone of PH diagnosis and clinical decision making.https://bit.ly/3gRSyWz

Pulmonary artery hemodynamics are associated with duration of nocturnal desaturation but not apnea-hypopnea index

STUDY OBJECTIVES

Sleep-disordered breathing and nocturnal hypoxia are prevalent among patients with precapillary pulmonary hypertension (PAH). The rationale for these associations remains unclear and these relationships have not been well studied in other forms of pulmonary hypertension (PH). We hypothesized that severity of sleep-disordered breathing and nocturnal hypoxia are associated with worsening pulmonary hemodynamics, regardless of hemodynamic profile.

METHODS

Four hundred ninety-three patients were divided into 4 groups: 1) no PH, 2) postcapillary pulmonary hypertension, 3) PAH, and 4) mixed PAH/postcapillary pulmonary hypertension. The relationship between right heart catheterization measurements and apnea-hypopnea index or the percentage of sleep time spent with oxygen saturation < 90% (T90) was calculated using multiple linear regression. Analysis of variance was used for between-group comparisons. Statistical models were adjusted for known confounders.

RESULTS

Apnea-hypopnea index did not differ between hemodynamic subgroups (P = .27) and was not associated with right atrial pressure (.11 ± .19, P = .55), cardiac index (.25 ± 1.64, P = .88), mean pulmonary artery pressure (-.004 ± .09, P = .97), or pulmonary artery occlusion pressure (.16 ± .14, P = .26). While patients with PH had a higher T90 than those without (mean 24.2% vs 11.7%, P < .001), there was no difference in T90 between individual PH subgroups (P = .70). T90 was associated with mean pulmonary artery pressure (.55 ± .10, P < .0001), PVR (1.61 ± .49, P = .001), and right atrial pressure (.50 ± .20, P = .01), but not cardiac index (-.76 ± 1.73, P = .66), or pulmonary artery occlusion pressure (.23 ± .15, P = .13).

CONCLUSIONS

Increased PH severity was associated with longer duration of nocturnal hypoxia regardless of hemodynamic subgroup.

Transcatheter pulmonary denervation in patients with left heart failure with reduced ejection fraction and combined precapillary and postcapillary pulmonary hypertension: A prospective single center experience

OBJECTIVES

The present study was a prospective, single-center, single-arm study to investigate the efficacy of transcatheter pulmonary artery denervation (TPADN) in patients with combined postcapillary and precapillary PH (Cpc-PH) associated with left heart failure with reduced ejection fraction (HF-rEF).

BACKGROUND

Pulmonary hypertension (PH) in patients with left ventricular systolic dysfunction has a negative impact on outcome.

METHODS

The combination of pulmonary artery systolic pressure (PAPs) ≥60 mmHg, transpulmonary pressure gradient (TPG) ≥12 mmHg, nonreversible mean PAP, and pulmonary vascular resistance (PVR) ≥3.5 Wood Units was considered as too high risk for heart transplantation (HTx). The clinical efficacy endpoint was an improvement in 6-min walking test and the hemodynamic endpoints were changes in PAPs, PVR, and TPG between baseline and 6 months. Circumferential radiofrequency applications were delivered around distal main, left and right pulmonary arteries. At each ablation point temperature was 45°C and energy 10 W.

RESULTS

TPADN was performed in 10 patients. At 6-month in 5 patients we observed reduction in PAP, PVR, TPG, and DPG and then 1 had successful HTx, 2 are on HTx waiting list, 2 received LVADs, 2 patients did not improve, and 3 patients died.

CONCLUSIONS

TPADN may be beneficial in selected patients with HF-rEF and Cpc-PH.

Pulmonary vascular disease in the setting of heart failure with preserved ejection fraction

Heart failure with preserved ejection fraction (HFpEF) is defined as clinical features of heart failure, ideally with biomarker evidence such as elevated plasma natriuretic peptide levels, in the setting of an ejection fraction (EF) greater than 50% and imaging evidence of diastolic left ventricular dysfunction [1,2]. In the absence of cardiac imaging or invasive hemodynamics, this is a clinical syndrome that is often indistinguishable from heart failure with reduced ejection fraction (HFrEF). HFpEF and HFrEF present with a cadre of comparable signs and symptoms including jugular venous distention, pulmonary rales on auscultation, breathlessness, orthopnea, exercise intolerance, exertional dyspnea, fatigue and peripheral edema. HFpEF accounts for at least half of all diagnoses of heart failure [1,2]. Pulmonary hypertension (PH) is a common complication of HFpEF that is linked to worse disease morbidity and mortality. In fact, mortality has been linked to increases in the intrinsic pulmonary vascular resistance in the setting of increased left ventricular end diastolic pressure, characterized hemodynamically by rises in the transpulmonary pressure gradient, pulmonary vascular resistance or diastolic pressure gradient. Despite being the most common form of PH, there are no approved therapies for the treatment of PH secondary to HFpEF. This review will summarize the hemodynamic classifications of PH in the setting of HFpEF, mechanisms of disease, the potential contribution of pulmonary vascular disease to poor outcomes in patients with HFpEF, and new approaches to therapy.

Hemodynamics of the diastolic pressure gradients in acute heart failure: implications for the diagnosis of pre-capillary pulmonary hypertension in left heart disease

The diastolic pressure gradient (DPG) has been proposed as the metric of choice for the diagnosis of pulmonary vascular changes in left heart disease. We tested the hypothesis that this metric is less sensitive to changes in left atrial pressure and stroke volume (SV) than the transpulmonary gradient (TPG). We studied the effect of dynamic changes in pulmonary capillary wedge pressure (PCWP), SV, and pulmonary artery capacitance (PAC) on DPG and TPG in 242 patients with acute heart failure undergoing decongestive therapy with continuous hemodynamic monitoring. There was a close impact of PCWP reduction on TPG and DPG, with a 0.13 mmHg (95% confidence interval [CI] 0.07–0.19, P < 0.0001) and 0.21 mmHg (95% CI 0.16–0.25, P < 0.0001) increase for every 1 mmHg decrease in PCWP, respectively. Changes in SV had a negligible effect on TPG and DPG (0.19 and 0.13 mmHg increase, respectively, for every 10-mL increase in SV). Heart rate was positively associated with DPG (0.41-mmHg increase per 10 BPM [95% CI 0.22–0.60, P < 0.0001]). The resistance-compliance product was positively associated with both TPG and DPG (2.65 mmHg [95% CI 2.47–2.83] and 1.94 mmHg [95% CI 1.80–2.08] for each 0.1-s increase, respectively). In conclusion, DPG is not less sensitive to changes in left atrial pressure and SV compared with TPG. Although DPG was not affected by changes in PAC, the concomitant increase in the resistance-compliance product increases DPG.

Intravenous sildenafil acutely improves hemodynamic response to exercise in patients with connective tissue disease

Background

Hemodynamic assessment during exercise may unmask an impaired functional reserve of the right ventricle and the pulmonary vasculature in patients with connective tissue disease. We assessed the effect of intravenous sildenafil on the hemodynamic response to exercise in patients with connective tissue disease.

Methods

In this proof-of-concept study, patients with connective tissue disease and mean pulmonary arterial pressure (mPAP) >20 mm Hg were subjected to a supine exercise hemodynamic evaluation before and after administration of intravenous sildenafil 10 mg.

Results

Ten patients (four with moderately elevated mPAP 21–24 mm Hg; six with mPAP >25 mm Hg) underwent hemodynamic assessment. All of them showed markedly abnormal exercise hemodynamics. Intravenous sildenafil was well tolerated and had significant hemodynamic effects at rest and during exercise, although without pulmonary selectivity. Sildenafil reduced median total pulmonary resistance during exercise from 6.22 (IQR 4.61–8.54) to 5.24 (3.95–6.96) mm Hg·min·L^-1 (p = 0.005) and increased median pulmonary arterial capacitance during exercise from 1.59 (0.93–2.28) to 1.74 (1.12–2.69) mL/mm Hg (p = 0.005).

Conclusions

In patients with connective tissue disease who have an abnormal hemodynamic response to exercise, intravenous sildenafil improved adaption of the right ventricular-pulmonary vascular unit to exercise independent of resting mPAP. The impact of acute pharmacological interventions on exercise hemodynamics in patients with pulmonary vascular disease warrants further investigation.

Trial registration

Clinicaltrials.gov NCT01889966.

Right Ventricular Function in Left Heart Disease

Right ventricular (RV) function is an independent prognostic factor for short- and long-term outcomes in cardiac surgical patients. Patients with mitral valve (MV) disease are at increased risk of RV dysfunction before and after MV operations. Yet RV function is not part of criteria for decision making or risk stratification in this setting. The role of MV disease in the development of pulmonary hypertension (PHTN) and the ultimate impact of PHTN on RV function have been well described. Nonetheless, there are other mechanisms by which MV disease and MV surgery affect RV performance. Research suggests that PHTN may not be the most important determinant of RV dysfunction. Both RV dysfunction and PHTN have independent prognostic significance. This review explores the unique anatomic and functional features of the RV and the pathophysiologic and prognostic implications of RV dysfunction in patients with MV disease in the perioperative period.

Pulmonary hypertension associated with left heart disease: Updated Recommendations of the Cologne Consensus Conference 2018

In the summer of 2016, delegates from the German Society of Cardiology (DGK), the German Respiratory Society (DGP), and the German Society of Pediatric Cardiology (DGPK) met in Cologne, Germany, to define consensus-based practice recommendations for the management of patients with pulmonary hypertension (PH). These recommendations were built on the 2015 European Pulmonary Hypertension guidelines, aiming at their practical implementation, considering country-specific issues, and including new evidence, where available. To this end, a number of working groups was initiated, one of which was specifically dedicated to PH associated with left heart disease. In this context, the European Guidelines point out that the drugs currently approved to treat patients with PAH (prostanoids, endothelin receptor antagonists, phosphodiesterase type 5 inhibitors, sGC stimulators) have not sufficiently been investigated in other forms of PH. However, despite the lack of respective efficacy data, an uncritical use of targeted PAH drugs in patients with PH associated with left heart disease is currently observed at an increasing rate. This development is a matter of concern. On the other hand, PH is a frequent problem that is highly relevant for morbidity and mortality in patients with left heart disease. In that sense, the distinction between isolated post-capillary pulmonary hypertension (IpcPH) and combined post- and pre-capillary pulmonary hypertension (CpcPH) and their proper definition may be of particular relevance. The detailed results and recommendations of the working group on PH associated with left heart disease, which were last updated in the spring of 2018, are summarized in 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.

A critical appraisal of transpulmonary and diastolic pressure gradients

Pulmonary hypertension (PH) resulting from left heart failure is an increasingly recognized clinical entity. To distinguish isolated postcapillary PH from combined post‐ and precapillary PH, the use of a diastolic pressure gradient (DPG = diastolic Pulmonary Artery Pressure − Pulmonary Arterial Wedge Pressure, dPAP − PAWP) has been advocated over the transpulmonary pressure gradient (TPG = mean Pulmonary Artery Pressure − PAWP, mPAP − PAWP) since DPG was suggested to be independent of cardiac output (CO) and only slightly related to PAWP, while TPG depends on both. We quantitatively derived and compared the DPG and TPG. Using right heart catheterization data (n = 1054), we determined systolic pulmonary artery pressure (sPAP), dPAP and mPAP, PAWP, and CO. From this data, we derived TPG and DPG and tested their dependence on PAWP and CO. We found that dPAP and sPAP are proportional with mPAP over a wide range of PAWP (1–31 mmHg), with dPAP = 0.62mPAP and sPAP = 1.61mPAP. As a consequence, TPG and DPG are equally dependent on PAWP: TPG = mPAP − PAWP, and DPG = 0.62mPAP − PAWP. Furthermore, we showed that both TPG and DPG depend on CO. The absolute increase in DPG with CO is 62% of the TPG increase with CO, but the relative dependence is the same. Both TPG and DPG depend on PAWP and CO. Thus, in principle, there are no major advantages for using DPG to distinguish postcapillary pulmonary hypertension from combined post‐ and precapillary pulmonary hypertension.

Late Onset Postcapillary Pulmonary Hypertension in Patients With Transposition of the Great Arteries and Mustard or Senning Baffles

Background

There is a paucity of data regarding late‐onset pulmonary hypertension (PH) in patients with transposition of the great arteries and atrial switch surgery.

Methods and Results

A retrospective cohort study was conducted on 140 adults with transposition of the great arteries and atrial switch surgery, age 37.3±7.8, 37.1% female, in order to assess the prevalence and characteristics of late‐onset PH and explore associated factors. Patients were followed for a median of 32.3 years after atrial switch surgery and 10.0 years after their first referral visit. PH was detected in 18 of 33 (54.5%) patients who had invasive hemodynamic studies. Average age at diagnosis of PH was 33.9±8.1 years. PH was postcapillary in all, with a mean pulmonary artery pressure of 36±12 mm Hg and mean pulmonary capillary wedge pressure of 28±8 mm Hg. PH was diagnosed in 13 of 17 (76.5%) patients who had cardiac catheterization for heart failure or decreased exercise tolerance. In multivariable analyses, systemic hypertension (odds ratio 9.4, 95% confidence interval 2.2‐39.4, P=0.002) and heart failure or New York Heart Association class III or IV symptoms (odds ratio 49.8, 95% confidence interval 8.6‐289.0, P<0.001) were independently associated with PH. Patients with PH were more likely to develop cardiovascular comorbidities including atrial (P=0.001) and ventricular (P=0.008) arrhythmias, require hospitalizations for heart failure (P<0.001), and undergo tricuspid valve surgery (P<0.001). Mortality was significantly higher in patients with PH (hazard ratio 9.4, 95% confidence interval 2.1‐43.0], P<0.001).

Conclusions

Late‐onset postcapillary PH is highly prevalent in adults with transposition of the great arteries and atrial switch surgery and is associated with an adverse prognosis.

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.

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.

Impact of postoperative pulmonary hypertension on outcome after heart transplantation

OBJECTIVES

We wanted to investigate the effects of postoperative pulmonary hypertension (PH_postop: mean pulmonary artery pressure [MPAP] ≥ 25 mmHg), diastolic pressure gradient (DPG), pulmonary vascular resistance (PVR), and repeated hemodynamic measurements on long-term survival after heart transplantation (HT).

DESIGN

Eighty-nine patients who underwent HT at Skåne University Hospital in Lund in the period 1988-2010 and who were evaluated with right-heart-catheterization at rest, prior to HT and repeatedly during the first postoperative year, were grouped based on their MPAP, DPG, and PVR.

RESULTS

One year after HT, survival was lower in patients with PH_postop than in those without, in patients with DPG ≥7 mmHg than in those with DPG <7 mmHg, and in patients with PVR >3 WU than in those with PVR ≤3 WU. Moreover, compared to patients with no PH_postop or with PH_postop at one evaluation during the first year after HT, PH_postop at repeated evaluations was associated with higher mortality (hazard ratio 3.4, 95% CI 1.4-8.0). There was no significant difference in acute cellular rejection between patients with and without PH_postop, but postoperative kidney function was worse in patients with repeated PH_postop.

CONCLUSIONS

When defined according to present guidelines, PH one year after HT may emerge as a prognostic marker for long-term outcome after HT. Moreover, PH_postop at repeated evaluations during the first year after HT had stronger prognostic value than PH_postop at a single examination, illustrating a means of identifying a high-risk population. However, confirmation in larger multi-center studies is warranted.

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

AIMS

The diastolic pulmonary pressure gradient (DPG) has recently been introduced as a specific marker of combined pre-capillary pulmonary hypertension (Cpc-PH) in left heart disease (LHD). However, its diagnostic and prognostic superiority compared with traditional haemodynamic indices has been challenged lately. Current recommendations explicitly denote that in the normal heart, DPG values are greater than zero, with DPG ≥7 mmHg indicating Cpc-PH. However, clinicians are perplexed by the frequent observation of DPG <0 mmHg (DPG_NEG ), as its physiological explanation and clinical impact are unclear to date. We hypothesized that large V-waves in the pulmonary artery wedge pressure (PAWP) curve yielding asymmetric pressure transmission might account for DPG_NEG and undertook this study to clarify the physiological and prognostic implications of DPG_NEG .

METHODS AND RESULTS

Right heart catheterization and echocardiography were performed in 316 patients with LHD due to primary myocardial dysfunction or valvular disease. A total of 256 patients had PH-LHD, of whom 48% demonstrated DPG_NEG . The V-wave amplitude inversely correlated with DPG (r = -0.45, P < 0.001) in patients with low pulmonary vascular resistance (PVR), but not in those with elevated PVR (P > 0.05). Patients with large V-waves had negative and lower DPG than those without augmented V-waves (P < 0.001) despite similar PVR (P >0.05). Positive, but normal DPG (0-6 mmHg) carried a worse 2-year prognosis for death and/or heart transplantation than DPG_NEG (hazard ratio 2.97; P < 0.05).

CONCLUSION

Our results advocate against DPG_NEG constituting a measurement error. We propose that DPG_NEG can partially be ascribed to large V-waves and carries a better prognosis than DPG within the normal positive range.

Right heart catheterisation: best practice and pitfalls in pulmonary hypertension

Right heart catheterisation (RHC) plays a central role in identifying pulmonary hypertension (PH) disorders, and is required to definitively diagnose pulmonary arterial hypertension (PAH). Despite widespread acceptance, there is a lack of guidance regarding the best practice for performing RHC in clinical practice. In order to ensure the correct evaluation of haemodynamic parameters directly measured or calculated from RHC, attention should be drawn to standardising procedures such as the position of the pressure transducer and catheter balloon inflation volume. Measurement of pulmonary arterial wedge pressure, in particular, is vulnerable to over- or under-wedging, which can give rise to false readings. In turn, errors in RHC measurement and data interpretation can complicate the differentiation of PAH from other PH disorders and lead to misdiagnosis. In addition to diagnosis, the role of RHC in conjunction with noninvasive tests is widening rapidly to encompass monitoring of treatment response and establishing prognosis of patients diagnosed with PAH. However, further standardisation of RHC is warranted to ensure optimal use in routine clinical practice.

The Diagnostic Challenge of Group 2 Pulmonary Hypertension

Pulmonary hypertension (PH) secondary to left heart diseases associated with an increased pulmonary venous pressure is the second of a total of five groups recognized in the classification of PH. Group 2 PH is the commonest form of PH, and is associated with high morbidity and mortality. The diagnosis of group 2 PH relies on a clinical probability assessment in which echocardiography plays a major role, eventually followed by the invasive measurements of a mean pulmonary artery pressure (mPAP) ≥25mmHg and a wedged PAP (PAWP) >15mmHg. This combination of mPAP and PAWP defines "post-capillary PH" (pcPH). Post-capillary PH is most often associated with a diastolic pressure gradient (DPG) or gradient between diastolic PAP and PAWP <7mmHg and/or a pulmonary vascular resistance (PVR) ≤3Wood units (WU), and is called isolated pcPH (IpcPH). Postcapillary PH with a DPG ≥7mmHg and/or a PVR >3WU is then combined pre- and postcapillary PH (CpcPH). Post-capillary PH is associated with a decreased survival in proportion to increased PAP and decreased right ventricular (RV) ejection fraction. CpcPH occurs in 12-13% of patients with pcPH. CpcPH is associated with pulmonary vascular remodeling and altered RV-arterial coupling. The prognosis of CpcPH is poor.

2015 ESC/ERS Guidelines for the diagnosis and treatment of pulmonary hypertension

Guidelines summarize and evaluate all available evidence on a particular issue at the time of the writing process, with the aim of assisting health professionals in selecting the best management strategies for an individual patient with a given condition, taking into account the impact on outcome, as well as the risk–benefit ratio of particular diagnostic or therapeutic means. Guidelines and recommendations should help health professionals to make decisions in their daily practice. However, the final decisions concerning an individual patient must be made by the responsible health professional(s) in consultation with the patient and caregiver as appropriate.

Effects of sildenafil on invasive haemodynamics and exercise capacity in heart failure patients with preserved ejection fraction and pulmonary hypertension: a randomized controlled trial

BACKGROUND

Heart failure with preserved ejection fraction (HFpEF), with associated pulmonary hypertension is an increasingly large medical problem. Phosphodiesterase (PDE)-5 inhibition may be of value in this population, but data are scarce and inconclusive.

METHODS AND RESULTS

In this single centre, randomized double-blind, placebo-controlled trial, we included 52 patients with pulmonary hypertension [mean pulmonary artery pressure (PAP) >25 mmHg; pulmonary artery wedge pressure (PAWP) >15 mmHg] due to HFpEF [left ventricular ejection fraction (LVEF) ≥45%]. Patients were randomized to the PDE-5 inhibitor sildenafil, titrated to 60 mg three times a day, or placebo for 12 weeks. The primary endpoint was change in mean PAP after 12 weeks. Secondary endpoints were change in mean PAWP, cardiac output, and peak oxygen consumption (peak VO2). Mean age was 74 ± 10 years, 71% was female, LVEF was 58%, median NT-proBNP level was 1087 (535-1945) ng/L. After 12 weeks, change in mean PAP was -2.4 (95% CI -4.5 to -0.3) mmHg in patients who received sildenafil, vs. -4.7 (95% CI -7.1 to -2.3) mmHg in placebo patients (P = 0.14). Sildenafil did not have a favourable effect on PAWP, cardiac output, and peak VO2. Adverse events were overall comparable between groups.

CONCLUSION

Treatment with sildenafil did not reduce pulmonary artery pressures and did not improve other invasive haemodynamic or clinical parameters in our study population, characterized by HFpEF patients with predominantly isolated post-capillary pulmonary hypertension. (ClinicalTrials.gov, number NCT01726049).