Is pulmonary artery wedge pressure a reliable surrogate of left ventricular end-diastolic pressure during exercise for diagnosing HFpEF in patients with unexplained dyspnea?

Background

Left ventricular end-diastolic pressure (LVEDP) is the gold-standard for the assessment of LV filling pressure. For practical reasons, pulmonary artery wedge pressure (PAWP) is used as a surrogate for LVEDP. However, the interposition of the left atrium (LA) may account discrepancies between LVEDP and PAWP. The imprecision of both end-diastolic (or mid-A) and mean PAWP estimates for LVEDP has been widely described for cardiac catheterization at rest. PAWP measurement during exercise has been advocated to discriminate heart failure with preserved ejection fraction (HFpEF) from non-cardiac dyspnea, with an end-expiratory pathologic threshold ≥25 mmHg. However, a formal comparison of PAWP (either mid-A or mean PAWP) vs LVEDP during exercise has never been performed.

Aim

To compare LVEDP and PAWP during exercise.

Methods

We retrospectively analyzed consecutive patients with unexplained dyspnea and a normal LV ejection fraction, who had a clinical indication of right and left heart catheterization at rest and during exercise to assess unexplained dyspnea. Patients with mitral regurgitation ≥ moderate were excluded. Hemodynamic measurements were always taken at end-expiration.

Results

Forty-six consecutive patients were included in the analysis (80% with a peak mean PAWP ≥25 mmHg). We found a good correlation between both mid-A and mean PAWP on one side, and LVEDP on the other side (R2>0.55). At peak exercise, mid-A PAWP had no bias as compared with LVEDP, while mean PAWP slightly overestimated LVEDP by 1–2 mmHg. However, confidence intervals were quite large (Figure 1), suggesting imprecision of PAWP estimates for LVEDP in the individual patient. A disagreement between mean PAWP and LVEDP, using a threshold of ≥25 mmHg for both variables at peak exercise, was found in 11% of patients. In 4% of them, mean PAWP was ≥25 but LVEDP <25 mmHg, due to the appearance of tall V waves in the PAWP position (LA stiffness), increasing PAWP above LVEDP. In the remaining 7%, LVEDP was ≥25 but PAWP <25 mmHg. The latter patients, in whom HFpEF would have not been diagnosed based on peak PAWP alone, showed a PAWP increase during exercise relative to cardiac output changes (PAWP/CO slope) >2 mmHg/L/min, as an alternative parameter suggesting HFpEF.

Conclusions

In patients with unexplained exertional breathlessness, both mid-A and mean PAWP showed good correlation with LVEDP during exercise with minimal average bias, but their ability to estimate LVEDP was burdened by a relevant imprecision. Therefore, when in these patients peak PAWP is <25 mmHg, its assessment might need to be complemented by additional measurements (including LVEDP or PAWP/CO slope) to maximize the diagnostic power of exercise cardiac catheterization in identifying HFpEF.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship.

Right heart adaptation during exercise in pulmonary arterial hypertension and in pulmonary hypertension due to heart failure with preserved ejection fraction

Background

Right heart failure (RHF) represents the final step of distinct diseases, such as pulmonary arterial hypertension (PAH) and pulmonary hypertension (PH) due to heart failure with preserved ejection fraction (HFpEF). RHF may be defined by the inability of the heart to maintain a normal cardiac output (CO) or to do so at the expense of high right atrial pressure (RAP), at rest or during exercise.

However, exercise hemodynamic features suggestive of RHF, as well as their determinants, have still not been defined.

Aim

We sought to i. define the limits of normal of RAP increase during exercise; ii. describe the behavior of RAP during exercise in PAH and in PH-HFpEF, and its relation to right heart afterload and preload.

Methods

We retrospectively analyzed data from consecutive patients referred for suspicion of PH, who underwent both a resting and exercise right heart catheterization at two centers with identical methodology. We included patients with PH-HFpEF or PAH. Right heart adaptation to exercise was described either using absolute or CO-normalized RAP increase during exercise (RAP/CO slope), this latter representing the inverse of the Frank-Starling reserve. A control cohort of subjects with normal hemodynamics at rest and during exercise served to define abnormal increase in RAP, i.e. values of RAP and RAP/CO slope > mean ± 2 standard deviation of controls.

Estimated stressed blood volume (eSBV), as a measure of effective preload, was computed using a commercially-available software.

Results

80 patients were included in the analysis, of which 29 were PH-HFpEF, 30 PAH and 21 controls.

HFpEF patients were older than PAH patients and with a higher burden of cardiovascular comorbidities (p<0.05). Sex representation, BMI, and NTproBNP values were similar in the two groups.

Mean pulmonary artery pressure (PAP), pulmonary vascular resistance (PVR) and total vascular resistance (TPR) were higher in PAH than in PH-HFpEF both at rest and during exercise (p<0.01), in spite of similar CO (Table 1). At rest, eSBV did not differ between HFpEF and PAH, but it was higher in HFpEF at peak exercise.

On average, PH-HFpEF had higher resting and peak RAP than PAH, as well as higher RAP/CO slope (Figure 1).

The upper limit of normal of exercise RAP and of RAP/CO slope, as determined in control subject, was 12 mmHg and 1.55 mmHg/L/min. A higher rate of HFpEF patients, compared with PAH, had a RAP/CO slope and a peak RAP above normal limits (78% and 91% of PH-HFpEF vs 47% and 44% of PAH, respectively, p<0.001).

RAP/CO slope in the whole cohort was associated with eSBV but not with right ventricular afterload measures (PAP, TPR, PVR).

Conclusions

PH-HFpEF display more frequently a steeper increase of RAP during exercise than PAH patients in spite of similar CO, suggesting a more exhausted Frank-Starling reserve. The steep RAP increase during exercise seems to reflect a dysfunctional preload rather than an afterload-mismatch.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship.

An updated meta-analysis of hemodynamics markers of prognosis in patients with pulmonary hypertension due to left heart disease

Background

Pulmonary hypertension (PH) is associated with a poor prognosis in patients with left heart disease (LHD). Several hemodynamic variables have been shown to predict outcome, including pulmonary vascular resistance (PVR), pulmonary artery compliance (PAC), and the diastolic pressure gradient (DPG). We sought to provide an updated analysis on the association of these variables with prognosis in PH-LHD.

Methods

We performed a systematic literature review including studies reporting association measurements between DPG and/or PVR and/or PAC and death in PH-LHD patients. These hemodynamic variables were extracted to estimate the pooled hazard ratio (HR) of adverse outcome for each one, and cumulative meta-analysis was performed to investigate temporal trends in the effects reported in the literature as well as the impact of sample size.

Results

17 articles were identified, including 9716 patients with LHD, heterogeneous in terms of age, sex, and etiology of cardiac disease. In this large population, we found that PVR (HR, 1.09; 95% CI: 1.06–1.12), DPG (HR, 1.02; 95% CI: 1.01–1.02) and PAC (HR, 0.73; 95% CI: 0.76–0.81) were associated with an increased risk of adverse outcome, albeit with a less solid performance of DPG (Figure 1). Similar results were found when hemodynamic variables were analyzed according to the thresholds commonly applied in clinical practice, or subdividing cohorts according to the underlying LHD (either heart failure with preserved or reduced left ventricular ejection fraction, or valvular heart disease). Furthermore, cumulative metanalysis indicated that these results are consistently stable since 2018 (Figure 2).

Conclusions

Despite the heterogeneity of PH-LHD group and the intrinsic limitations of each variable, PVR, DPG, and PAC have an established prognostic value in PH-LHD. The strongest correlation with PVR and PAC supports their use in defining disease severity and identifying a subgroup of patients at higher risk of adverse outcome. We believe that these results are consistent through the years and unlikely to change with the addition of further studies.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship.

Prognostic power of a new index of right ventricle-pulmonary artery coupling based on right ventricular volumes in patients with secondary tricuspid regurgitation

Background

Although echocardiographic surrogates of right ventricular -arterial coupling (RVAC) have been reported to be associated with outcome in patients with moderate or severe secondary tricuspid regurgitation (STR), pulmonary artery systolic pressure (SPAP) is difficult to be estimated using echocardiography in patients with severe STR.

Purpose

Accordingly, we evaluated the predictive power of indexes of RVAC obtained using RV volumes measured using three-dimensional echocardiography (3DE).

Methods

We prospectively enrolled 180 patients with moderate or severe STR and complete two-dimensional, Doppler and 3DE data. The composite endpoint of death for any cause and heart failure hospitalization was used as primary outcome.

Results

After a median follow up of 24 months (IQR: 2–48), 72 patients (40%) reached the primary endpoint. Most of the echocardiographic parameters of RV function were associated with outcomes. Among the different parameters of RVAC, the receiver operating curve (ROC) analysis selected the ratio between (RV stroke volume [SV]-RegVol)/ RV End-systolic volume (ESV) (i.e. the RV forward SV/ESV) as the best predictor of the combined endpoint (AUC 0.80 [IC 95% 0.73–087]), with a threshold value of 0.49.

Event-free survival of patients with RV forward SV/ESV higher and lower 0.49 has been performed (Figure 1).

Multivariable Cox proportional hazards models were constructed (Figure 2). Adding sequentially the 3D-RVEF, TAPSE/SPAP and the forward RV SV/RV ESV on top of a basal model made of TR severity, New York Heart Association (NYHA) functional class and tricuspid anulus plane systolic excursion (TAPSE), the χ2 of the model increased from 40 to 43 (p=0.13) by adding 3D RVEF, from 43 to 46 (p=0.04) by adding TAPSE/SPAP, and from 46 to 51 (p=0.02) by adding RV forward SV/ESV. Severe TR (HR 3.53 [CI 95%: 1.84–6.78], p<0.001) and RV forward SV/ESV <0.49 (HR 2.45 [CI 95% 1.16–5.18], p=0.02) were the only parameters independently associated with outcome.

Conclusions

The RV forward SV/ESV is an index of RVAC obtained by 3DE which is independent from SPAP and it is strongly associated with the occurrence of death or heart failure hospitalization in patients with STR.

Funding Acknowledgement

Type of funding sources: None.

A meta-analysis of exercise hemodynamics in heart failure with preserved ejection fraction: the relevance of PAWP/CO slope

Background

Exercise right heart catheterization (RHC) is considered the gold-standard test to diagnose heart failure with preserved ejection fraction (HFpEF). However, exercise RHC is an insufficiently standardized technique, and current hemodynamic thresholds to define HFpEF are not universally accepted. We sought to describe the exercise hemodynamics profile of HFpEF cohorts reported in literature, as compared with control subjects.

Methods

We performed a systematic literature review following the PRISMA statement until December 2020. Studies reporting pulmonary artery wedge pressure (PAWP) at rest and peak exercise were extracted. Summary estimates of all hemodynamic variables were evaluated, stratified according to body position (supine/upright exercise). The PAWP / cardiac output (CO) slope during exercise was extrapolated.

Results

Twenty-seven studies were identified, providing data for 2180 HFpEF patients and 682 controls. At peak exercise, HfpEF cohorts showed a summary estimate of PAWP at peak which was twice as high as compared with control cohorts (30; 95% CI: 29–31 mmHg and 16; 95% CI: 15–17 mmHg, respectively), as well as of delta PAWP (15; 95% CI: 14–16 mmHg and 7; 95% CI: 6–8 mmHg, respectively), and of right atrial pressure (18; 95% CI: 16–19 mmHg and 8; 95% CI: 8–9 mmHg, respectively). These differences persisted after adjustment for age, sex, body mass index, body position. Additionally, summary estimates of PAWP at peak performed during supine exercise was slightly higher than that obtained in upright position only for HFpEF cohorts (supine position: 31; 95% CI: 30–32 mmHg vs upright position; 26; 95% CI: 25–27 mmHg, respectively, p-value<0.01). However, peak PAWP values were highly heterogeneous among the cohorts (I2=93%), with a relative overlap with controls (Figure 1). HFpEF had a significantly larger impairment in the hemodynamic response to exercise, witnessed by a steeper summary PAWP/CO slope than controls (3.75; 95% CI: 3.20–4.28 mmHg/L/min and 0.95; 95% CI: 0.30–1.59 mmHg/L/min, p-value <0.0001), even after adjustment for covariates (p=0.007) (Figure 2). Finally, summary estimates of PAWP/CO slope were higher in HFpEF cohorts performing exercise in the supine position compared with those in upright position (p<0.0001 and p=0.0002 at non-adjusted and adjusted analysis, respectively), but not in control cohorts (p=0.135 and p=0.966 at non-adjusted and adjusted analysis, respectively).

Conclusions

Despite methodological heterogeneity across centers, the hemodynamic profile of HFpEF patients is consistent across studies and characterized by a higher left and right filling pressure at rest compared with controls, enhanced by physical exercise. A PAWP/CO slope cut-off >2 mmHg/L/min seems to retain validity also for studies conducted in the supine position, potentially overcoming the need of different supine and upright PAWP cut-offs.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship.

P232 EXERTIONAL BREATHLESSNESS IN HYPERTROPHIC CARDIOMYOPATHY: OBSTRUCTION–INDEPENDENT SYMPTOMS IN A “PARADOXICAL” RESPONSE TO EXERCISE

A 66–y.o. man with hypertrophic cardiomyopathy presented with residual exertional dyspnea NYHA III a few years after surgical myectomy, mitral valve repair and ICD implantation. Echocardiography showed residual mild septal hypertrophy and mitral regurgitation (MR), and a variable obstruction of left ventricular outflow tract (LVOT), witnessed by a pressure gradient ranging from 15 to 50–70 mmHg (Figure 1). Exercise echocardiography did not suggest exercise–induced LVOT obstruction (LVOTO) or functional MR. We thus performed a thorough invasive hemodynamic evaluation at rest and during exercise. LVOTO was present at rest, with a maximum pressure gradient of 90–100 mmHg and typical “spike–and–dome” configuration of the aortic pulse contour (Figure 2), with LV end–diastolic pressure (LVEDP) at the upper limit of normal (15 mmHg) and normal pulmonary hemodynamics. During exercise, we observed a paradoxical reduction of the LVOTO (30–40 mmHg at peak, Figure 2). Pulmonary hypertension developed during exercise, due to LV diastolic dysfunction, witnessed by a marked increase in pulmonary artery wedge pressure and LVEDP (up to 25 mmHg and 30 mmHg at peak, respectively). Cardiac output (CO) reserve was at the lower limits of normal, mainly due to chronotropic incompetence, responsible for a mildly reduced exercise capacity (peak oxygen consumption was 20 mL/Kg/min, 75% of predicted). Thus, cardiac catheterization confirmed the presence of a relevant LVOTO at rest, that was not directly related to exertional symptoms. These latter were mainly attributable to LV diastolic dysfunction and reduced CO reserve. These findings helped us driving treatment decision in a tailored way: beta–blockers were not uptitrated, because of their negative inotropic effect, and high–risk septal reduction therapies were excluded, since exertional symptoms were unrelated to LVOTO. However, an attempt to reduce LVOTO was done by DDD sequential pacing through the ICD. Pacing could induce mechanical dyssynchrony and reduce LVOTO by increasing the end–systolic LVOT diameter. The simultaneous echocardiographic monitoring highlighted an acute reduction of LVOT gradient from 50–70 mmHg to 20–30 mmHg (Figure 3).

This case suggests that, in well–selected cases, patients’ management based on pathophysiological reasoning may help to define the etiopathogenetic mechanism underlying symptoms, and to drive treatment decision in a patient–centered way.

P284 THE RIGHT HEART ADAPTATS TO EXERCISE MORE EFFICIENTLY IN PULMONARY ARTERIAL HYPERTENSION THAN IN PULMONARY HYPERTENSION DUE TO HEART FAILURE WITH PRESERVED EJECTION FRACTION

Background

Right heart failure (RHF) represents the final step of distinct diseases, differently involving the pulmonary circulation, such as pulmonary arterial hypertension (PAH) and pulmonary hypertension (PH) due to heart failure with preserved ejection fraction (HFpEF). Exercise may unmask right heart maladaptation as a sign of RHF, but cut–offs for right atrial pressure (RAP) rise during exercise remain to be defined. We hypothesized that PH–HFpEF may present with worse right heart adaptation to exercise than PAH due to increased chamber stiffness and dysfunctional preload.

Aim

We sought to describe the behavior of RAP during exercise in PAH and in PH–HFpEF, and the mechanisms underlying right heart maladaptation.

Methods

We performed a retrospective analysis of data (2007–2021) obtained from patients with either PAH or PH–HFpEF who underwent a right heart catheterization at rest and during exercise. Right heart adaptation to exercise was described using either absolute or cardiac output (CO)–normalized RAP increase during exercise (RAP/CO slope). Patients with non–cardiac dyspnea (NCD) served to define RAP limits of normality. Estimated stressed blood volume (eSBV), as a measure of effective preload, was computed based on hemodynamics using a commercially–available software.

Results

Ninety–four patients were included (32 PH–HFpEF, 32 PAH and 30 NCD). The upper limit of normal for absolute peak RAP and RAP/CO slope were 12 mmHg and 1.55 mmHg/L/min. Compared with PH–HFpEF, PAH patients showed higher systolic, diastolic and mean pulmonary artery pressure (PAP) as well as higher indices of right ventricular afterload both at rest and during exercise, but lower filling pressures and similar CO (Figure 1).In particular, PH–HFpEF had higher peak RAP and higher RAP/CO slope than PAH (Figure 1,2). Additionally, 78% and 91% of PH–HFpEF, as compared with 47% and 44% of PAH had a RAP/CO slope and a peak RAP above normal, respectively (p < 0.001). PH–HFpEF presented with higher increase in eSBV, and higher peak eSBV values than PAH (p < 0.05), despite similar resting levels. RAP/eSBV slope was upward shifted (at a given effective preload, RAP was higher) while CO/eSBV slope was flatter (at a given effective preload, CO was lower) in PH–HFpEF as compared with PAH (Figure 3).

Conclusions

PH–HFpEF display worse right heart maladaptation to exercise than PAH, likely due to a combination of increased right heart stiffness and a more exhausted Frank–Starling reserve.

P245 A RARE CAUSE OF OVERESTIMATION OF PULMONARY PRESSURE BY ECHOCARDIOGRAPHY: WHEN HEMODYNAMICS RELIEVES ECHOCARDIOGRAPHY AND ECHOCARDIOGRAPHY EXPLAINS HEMODYNAMICS

Echocardiography is the gatekeeper of the diagnostic workflow of pulmonary hypertension (PH). However, it lacks precision, and right heart catheterization (RHC) may be needed in selected cases. A morbidly obese 47–year–old woman (BMI= 58 Kg/m2) with dyspnea NYHA II was referred to our Center after a high probability of PH was found at echocardiography, this latter performed as a routine assessment before bariatric surgery. Despite a suboptimal acoustic window, the tricuspid regurgitant jet profile was well–defined, with an estimated systolic pulmonary artery pressure (PAP) of 100 mmHg. There were no overt echocardiographic signs of left heart disease. During RHC, mean PAP was just above normal values, with filling pressures at the upper limit of normal (Figure 1), high cardiac index (3.6 L/min/m2) and normal pulmonary vascular resistance (1.4 WU). The echocardiographic estimate of high systolic PAP was explained by an intraventricular RV pressure gradient of about 100 mmHg (Figure 2). Oximetry ruled out a significant intracardiac shunt. Since resting hemodynamics did not explain the patient’s symptoms, the patient pre–test probability of having heart failure with preserved ejection fraction (HFpEF) was intermediate–high, and PAWP was in a grey–zone. Accordingly, we performed an exercise RHC. The test eventually unmasked HFpEF, as witnessed by an abnormal increase of PAWP and LV end–diastolic pressure (Figure 1 panel C and D). Exercise capacity was mildly reduced (71% of predicted) due to peripheral limitation with normal cardiac and respiratory reserves. Transesophageal echocardiography was then performed. It showed a muscular obstruction below the infundibulum dividing the RV into a high–pressure apical portion and a low–pressure infundibulum (Figure 3). This rare congenital anomaly was also associated with a restrictive perimembranous ventricular septal defect. Double–chambered RV has been reported to present rarely in adults, but it might be a cause of false Doppler echocardiographic estimate of PAP. Based on a meticulous invasive hemodynamic characterization at rest and during exercise, integrated with cardiovascular imaging, we could perform such a diagnosis. This congenital anomaly did not fully explain the patient’s symptoms, which may better be attributed to cardiovascular complication of obesity (HFpEF). Accordingly, we referred the patient for bariatric surgery first, postponing the indication to cardiac surgery during the follow–up.

P283 PROGRESSION OF PULMONARY ARTERIAL HYPERTENSION OR LEFT HEART DISEASE? DO EXERCISE!

An 80–year–old man, diagnosed with idiopathic pulmonary arterial hypertension (PAH) in 2012 and treated with sildenafil, experienced his first hospitalization for heart failure in June 2019. He had several cardiovascular risk factors (overweight, hypertension, diabetes) and comorbidities (ischemic heart disease, and mild chronic obstructive pulmonary disease), whose progression was excluded. Since this event, he complained a progressive deterioration of the exertional dyspnea (NYHA III), with overt signs of fluid overload, right chambers dilation and high NTproBNP (1366 ng/L). However, the center taking care of this patient neither decided to fully re–evaluate him nor to escalate PAH–treatment due to his clinical profile (high suspicion of left heart disease, LHD). He then came to our pulmonary hypertension (PH) center where we decided to perform a cardiac catheterization, which showed the persistence of precapillary PH with high pulmonary vascular resistance, PVR (7.6 WU), low cardiac output, CO (2.2 L/min/m2), high right atrial pressure, RAP (12 mmHg). Pulmonary artery wedge pressure (PAWP) and left ventricular end–diastolic pressure (LVEDP) were at the upper limits of normal (13 mmHg and 16 mmHg, respectively) (Figure 1). Based on these “borderline” PAWP values, with an intermediate–high pre–test probability of left heart disease, we performed an exercise test with concomitant gas–exchange analysis on a cycle ergometer in the cath lab (Figure 2). Exercise induced a steep increase in pulmonary pressure (TPR 9 WU), unrelated to an exaggerate increase in PAWP or LVEDP (whose peak values reached 20 mmHg, with a PAWP/CO slope <2 mmHg/L/min), but entirely dependent on the precapillary component. Transpulmonary gradient (TPG)/CO slope was high, leading to an absent reduction in PVR (6.4 WU at peak), associated to severe increase in RAP (27 mmHg at peak, RAP/PAWP 1.4) (Figure 3). CO reserve was reduced (at peak 3.4 L/min/m2), due to both reduced increase in stroke volume and chronotropic incompetence. Accordingly, functional capacity was moderately–severely reduced (peak oxygen consumption was 8 ml/kg/min, 39% of predicted), with exercise hyperventilation. Once excluded LHD as the responsible of clinical worsening, and in consideration of the high–intermediate risk profile of this patient, we upgraded the PAH–specific therapy by adding macitentan, obtaining a subjective clinical improvement and a 3–years period of clinical stability.

P296 HIDDEN PERICARDIAL CONSTRICTION IN A PATIENT WITH CHRONIC PERICARDIAL EFFUSION AND “UNEXPLAINED” DYSPNEA

Constrictive physiology leads to exertional symptoms related to restrained diastolic filling and intracardiac/intrathoracic dissociation. However, these hemodynamic abnormalities might not be evident in some patients. A 55–year–old woman was referred to our center to perform a right and left cardiac catheterization because of “unexplained” dyspnea. Three years before she was found to have a large idiopathic pericardial effusion. Anti–inflammatory therapy did not result in any improvement. Since then, the patient complained dyspnea NYHA II–III, in the absence of any clinical and imaging sign of tamponade/pericardial constriction. At rest, there was no sign of constriction, but a relative hypovolemic status characterized by low pulmonary and filling pressures and cardiac output (CO) at the lower limits of normal. After a 500 mL saline load and passive legs raising, Kussmaul’s and “M” signs appeared on the right atrial pressure curve (Figure 1), the pulmonary artery wedge pressure (PAWP) – left ventricular end–diastolic pressure (LVEDP) gradient difference between expiration and inspiration was >5 mmHg (Figure 2), and ventricular systolic pressures went out of phase by 180°. Both right and left filling pressures as well as pulmonary pressures steeply increased in a concordant manner by about 10 mmHg after fluid load, in absence of a relevant increase in CO (Figure 3). Physical exercise performed thereafter showed an additional mild increase with a plateau pattern of all pressures, suggesting an upward–shift of the pressure/flow relationship (Figure 3). All these signs suggested a latent constrictive physiology. Despite this, the patient showed an optimal CO reserve coupled with a normal exercise capacity (peak oxygen consumption, VO2, 127% of predicted) that would have argued against our hypothesis. We then performed a diagnostic and evacuative pericardiocentesis. After the drainage of 130 ml of pericardial fluid, LV transmural pressure increased and CO at rest was fully normalized. Moreover, no hemodynamic sign of constriction could be observed even after a 1000 ml saline load. The patient reported disappearance of exertional breathlessness, objectivated by an increase in peakVO2 by 20% as compared with the previous test. Thus, our case underscores how subtle the hemodynamic impact of pericardial effusion can be, with the need of well–tailored diagnostic exams to explain otherwise “unexplained” patients’ symptoms, with potential therapeutic implications.

Impact of leaflet-tethering angle correction on the assessment of tricuspid regurgitation severity using the PISA method

Funding Acknowledgements

Type of funding sources: None.

Background

Severe tricuspid regurgitation (TR) is associated with excess mortality and morbidity. Therefore, assessment of TR severity is pivotal. Calculation of the effective regurgitant orifice area (EROA) and the regurgitant volume (RVol) using flow convergence method (PISA) by echocardiography are still the recommended parameters to define TR severity. However, the distortion of the proximal convergence zone related to the extent of valve leaflet tethering may result in smaller PISA radius and in underestimation of TR severity. Correcting for the angle of the leaflet tethering could reduce errors due to geometric assumption of a flat valvular plane and improve the accuracy of the calculations.

Purpose: The aims of our study were

(1) to evaluate whether taking into account the extent of leaflet tethering by applying the angle correction (AC) in the PISA formula improves the accuracy of the quantitative assessment of TR severity; (2) to assess the potential clinical impact of AC.

Methods

Forty-one patients with functional TR (73.5 ± 11.8 years,51% men,36% sinus rhythm,17% severe), underwent 2D  and 3D echocardiography. We compared the RVol obtained by volumetric method (as reference) with the RVol by PISA with and without AC. TR RVol by volumetric method was calculated as: total RV stroke volume (RVSV) – left ventricular forward SV (LVSV), where RVSV was obtained by subtracting the end-systolic from end-diastolic RV volume measured by 3D echocardiography and LV SV was calculated by multiplying LV outflow area by velocity time integral (VTI)  (Fig. 1). TR RVol by PISA was calculated as EROA x VTITR. Uncorrected EROA was calculated using the formula: 6.28 r2 xVa/ PeakVTR (r - PISA radius, Va, aliasing velocity, PeakVTR – TR peak velocity). The corrected EROA accounting for the PISA geometric distortion by leaflet tethering angle (α) was calculated as: 6.28 r2 x Va (α/180)/ PeakV TR (PISAac), where α was measured using a protractor generated by dedicated software.

Results

Application of AC to PISA method resulted in larger EROA and RVol (0.34± 0.38 cm2 vs 0.24± 0.24cm2 and, 25.2± 19.3 mL vs 18.6 ± 13.1mL, respectively). The percentage change in EROAac was over 40%. When compared to the volumetric method, RVol by corrected PISA method was significantly closer and correlated (bias -3.95mL, LOA ± 6.41 mL,  r= .987; p< .001) than the conventional PISA without AC (bias -10.5 mL, LOA ± 15 mL, r= .975). Angle correction resulted in a change of TR severity in 32% of cases (Fig. 2) and in a greater concordance of TR severity grade with the volumetric method (75%, 31/41 with AC vs 52%, 22/41 without AC).

Conclusions

Angle-corrected PISA method that accounts for the extent of the leaflet tethering in TR provided significantly larger TR RVol that were closely correlated with the volumetric RVol by 3D echocardiography. A simple geometric angle correction of the proximal flow with PISA method reclassified up to 1/3 of patients with functional TR. Abstract Figure. Representation of study method  Abstract Figure. Reclassification of TR severity

Prognostic value of different echocardiographic indices reflecting right ventriculo-arterial coupling in a large cohort of patients with various cardiac diseases

Funding Acknowledgements

Type of funding sources: None.

Introduction – Non-invasive parameters used to assess right ventricular (RV) function, i.e. tricuspid annular plane systolic excursion (TAPSE), RV fractional area change (FAC), RV ejection fraction (RVEF), and RV free-wall longitudinal strain (RVFWLS) have shown their prognostic implications. However, since they are extremely load dependent, they do not provide an accurate representation of the RV intrinsic performance. On the other end, invasive indices of RV-arterial coupling (RVAC) derived from pressure-volume loops are not routinely performed, rising the urgency for more feasible, and reliable non-invasive estimates of RVAC.

Purpose – To: i. evaluate the prognostic value of echocardiography-derived RVAC surrogates: RVEF/systolic pulmonary artery pressure (sPAP), RVFWLS/sPAP, TAPSE/sPAP, FAC/sPAP, and RV stroke volume/end-systolic volume (SV/ESV), ii. identify the cut-off values associated to all-cause mortality; and iii. compare their prognostic value with that of classical parameters of RV function.

Methods – We prospectively enrolled 366 patients with various cardiac diseases, undergoing clinically-indicated comprehensive two- and three-dimensional echocardiography.

Results – During a mean follow-up of 7.6 ± 1 years, 80 (21.9%) patients died. At univariable Cox regression, most of the echocardiographic parameters were related to all-cause mortality. The echocardiographic parameters with significance at univariable analysis (p < 0.01) were included in a multivariable regression model. Left ventricular ejection fraction (LVEF), RVEF, TAPSE, RVEF/sPAP and RVFWLS/sPAP remained independently associated to all-cause mortality (p < 0.05 for all). Subsequently, they were tested in receiving operator characteristics (ROC) curves. At ROC analysis, RVEF/sPAP (area under the curve, AUC = 0.807, p < 0.001) and RVFWLS/sPAP (AUC = 0.743, p < 0.001) showed the greatest predictive value (p < 0.001 between them). However, all RV parameters significantly improved their prognostic values after indexing for sPAP (p < 0.01 for all). The best cut-offs to predict the outcome were 1.5 for RVEF/sPAP (specificity 71%, sensitivity 83%) and 0.67 for RVFWLS/sPAP (specificity 72%, sensitivity 68%). At Kaplan-Meier analysis, patients with reduced RVAC (less than the predefined cut-offs) had significantly lower probability of survival (p < 0.001 for all).

Conclusion – RVAC surrogates provide incremental prognostic value compared to standard RV functional measurements. RVEF/sPAP, with a cut-off value of 1.5, was the best parameter for risk stratification, and was independently related to all-cause mortality. Abstract Figure. Prognostic value of RVAC surrogates  Abstract Figure. Kaplan-Meier curves survival probability

Right heart chambers geometry and function in patients with the atrial and the ventricular phenotypes of functional tricuspid regurgitation

Funding Acknowledgements

Type of funding sources: None.

Introduction — Atrial functional tricuspid regurgitation (A-FTR) is a recently defined phenotype of FTR associated with persistent/permanent atrial fibrillation. Differently from the classical ventricular form of FTR (V-FTR), patients with A-FTR might present with severely dilated right atrium (RA) and tricuspid annulus (TA), and with preserved right ventricular (RV) size and systolic function. However, the geometry and function of the RV, RA and TA in patients with A-FTR and V-FTR remain to be systematically evaluated.

Purpose — Accordingly, we sought to: i. study the geometry and function of the RV, RA and TA in A-FTR by two- and three-dimensional transthoracic echocardiography; and ii. compare them with those found in V-FTR.

Methods — We prospectively analysed 113 (44 men, age 68 ± 18 years) FTR patients (A-FTR = 55 and V-FTR = 58) that were compared to two groups of age- and sex-matched controls to develop the respective Z-scores.

Results — The severity of FTR, and the degree of TA dilation were similar in A-FTR and V-FTR patients. The Z-scores of RV size were significantly larger, and those of RV function were significantly lower in V-FTR than in A-FTR (p < 0.001 for all). The RA was significantly enlarged in both A-FTR and V-FTR compared to controls (p < 0.001, Z-scores > 2), with similar RA maximal volumes (RAVmax) between A-FTR and V-FTR (p = 0.2). Whereas, the RA minimal volumes (RAVmin) were significantly larger in A-FTR than in V-FTR (p = 0.001).

Conclusion — Despite similar degrees of FTR, RAVmax and TA size, A-FTR patients show larger RAVmin than V-FTR patients. Conversely, V-FTR patients show dilated, more elliptic and dysfunctional RV than A-FTR patients. Abstract Figure. A-FTR versus V-FTR  Abstract Figure. Remodelling patterns in A-FTR and V-FTR

Sex, body size and right atrial volume are the main determinants of tricuspid annulus geometry in healthy volunteers. A 3D echo study using a novel, commercially-available dedicated software package

 

Tricuspid annulus (TA) sizing is essential for percutaneous and surgical procedures. Guidelines recommend to assess TA size by 2D echo (2DE) linear dimension; but TA is a complex 3D structure.

Aim

To identify physiological determinants of TA geometry parameters and their reference values using 3D echo (3DE) and a novel, commercially-available software in healthy volunteers.

Methods

254 healthy volunteers (113 men, mean age 47±11 years) were evaluated by 2D and 3DE. 3DE TA analysis was made in 228 of them (feasibility=90%). TA 3DE area, perimeter, diameters, sphericity index and coaptation (Figure) were assessed at mid-systole using a dedicated software package (4D AutoTVQ, GE Healthcare, Horton, N). 3D right atrial (RA) and ventricular (RV) volumes were measured.

Results

Normal values of 3D TA geometry parameters, RV and RA volumes are presented in table. 3D TA area, perimeter and diameters correlated with BSA (r=0.33 to 0.5, p<0.001) and were larger in men, independently of BSA (p<0.0001). There were no age-related changes in TA parameters (r<0.25, p=0.0001). 2D TA diameters measured in apical 4ch and RV focused views were significantly smaller than 3DE 4ch diameter (16±2 and 16±3 vs 17±3, p<0.0001). RA maximal volumes had the strongest correlation with 3D TA area (r=0.65), compared with RV end-diastolic (r=0.55) and end-systolic (r=0.51) volumes (p<0.0001). By multivariable linear regression, RA maximal volume, sex and BSA, but not RV volumes, were independent predictors of 3D TA area (R2=0.46, p<0.0001).

Conclusions

Reference values for TA metrics should be sex-specific and indexed to BSA. 2DE underestimates TA dimensions. Even if both RA and RV volumes correlate significantly with TA area, only RA maximum volume was an independent predictor of its size at mid-systole.

3D tricuspid annulus parameters

Funding Acknowledgement

Type of funding source: None

P4685Validation of noninvasive pulmonary artery pressure/flow relationship: echocardiography vs right heart catheterization

Background

Invasive pressure-flow (P/Q) relationship of the pulmonary circulation can detect the presence of pulmonary hypertension (PH) during exercise and provide information on patients' symptoms and assess disease severity. Doppler-echocardiography was reported to provide accurate but imprecise noninvasive estimates of both resting and exercise pulmonary haemodynamics. However, data on the direct comparison of invasive vs noninvasive approaches to build pressure-flow relationship are scarce.

Purpose

To compare echocardiographic estimates with invasive measurements of P/Q relationship of the pulmonary circulation during exercise.

Methods

Patients undergoing a clinically indicated right heart catheterization and echocardiography were studied at rest and during exercise. The ratio between mean pulmonary artery pressure and cardiac output at peak exercise (TPR), as well as P/Q slope throughout exercise were calculated. Both TPR and P/Q slope are abnormal when ≥3 mmHg/L/min. Echocardiographic estimates were compared with invasive measurements.

Results

Sixty patients were included (mean age 65±14 years, 73% female). PH was present at rest in 38 cases (63%), of precapillary origin in 23 (61%). Heart failure with preserved ejection fraction was diagnosed in 23 patients, of which 17 had no PH at rest. TPR at peak exercise and P/Q slope were abnormal (≥3 mmHg/L/min) in the majority of patients (56 and 45 subjects, respectively).

Echocardiographic estimates of P/Q slope and TPR correlated significantly although weakly with invasive measurements (R2=0.38 and 0.56, respectively, p<0.001). Bias of echocardiography for P/Q slope and TPR was 1.1±4.2 and 0.4±2.9 mmHg/L/min, respectively (figure). Sensitivity of echocardiography to detect an abnormal TPR or P/Q slope (i.e. ≥3 mmHg/L/min) was 100 and 98%, respectively, faced by low specificity (0 and 33%, respectively).

Figure 1

Conclusions

Doppler-echocardiography can provide rather accurate and sensitive but imprecise estimates of pressure-flow relationships of the pulmonary circulation during exercise. This intrinsic imprecision may limit its use in clinical practice.

P4437Exercise limitation in systemic sclerosis: a case-controlled study

Introduction

Interstitial lung disease and pulmonary hypertension are the leading causes of morbidity and mortality in patients with systemic sclerosis (SSc). Exercise-induced dyspnea is the first manifestation of both complications, which explains why the value of resting tests to predict preclinical heart or lung involvement is limited. Cardiopulmonary exercise testing (CPET) offers a comprehensive approach to identify the cause of exercise limitation. However, the role of CPET in SSc patients without demonstrated cardiac and/or respiratory disease has not been extensively investigated.

Aim

We sought to compare the cardiopulmonary adaptation to exercise of SSc patients without cardiac or pulmonary disease vs healthy volunteers.

Methods

SSc patients (normal resting echocardiography and pulmonary functional test) and healthy volunteers were prospectively enrolled. They underwent maximal symptom-limited CPET, exercise echocardiography (EXEcho), and 6 minutes walk test. Results were compared after adjustment for age and gender.

Results

Thirty-nine patients (54±12 years) and 43 healthy subjects (46±11 years) were included.

Workload was lower in patients than controls (84±42 vs 178±58 W, p<0.001), with similar respiratory exchange ratio (1.27±0.11 vs 1.28±0.10, p=0.570) at peak exercise. Patients had lower oxygen uptake (VO2) at peak exercise (17±6 vs 30±8 ml min kg–1, p<0.001), and higher minute ventilation/carbon dioxide production (VE/VCO2) slope (41±8 vs 33±5, p<0.001) than controls (Figure 1). They had higher VE/VCO2 ratio (40±7 vs 30±3, p<0.001) and lower end-tidal pCO2 (PetCO2) (35±5 vs 41±3 mmHg, p<0.001) at the ventilatory threshold (VT). Respiratory reserve was preserved, and peripheral oxygen saturation was normal at peak exercise in both groups.

Resting echocardiography revealed larger left atrium in SSc-patients (24±8 vs 20±7 ml/m2, p=0.013) and higher estimated left atrial pressure (LAP) (10±2 vs 8±2 mmHg, p=0.001) vs controls. At ExEcho, total pulmonary resistance (TPR) was higher (3.2±0.6 vs 2.6±0.5 WU, p=0.003) and right ventricular function markers were lower at peak exercise in patients vs controls, despite similar values at rest. Plasma NT-proBNP was within normal range in all patients.

Walk distance was shorter in SSc-patients vs controls (505±80 vs 624±50 m, p<0.001), and correlated with peak VO2, VE/VCO2 slope, and VE/VCO2 at VT.

In Ssc patients, peak VO2 also correlated with DLCO (r=0.640, p<0.001), with left atrial volume (r=−0.344, p=0.002), and with estimated LAP (r=−0.490, p<0.001) but not with NT-proBNP or lung volumes.

Conclusion

The combination of low peak VO2, high VE/VCO2 slope, low PetCO2, and high respiratory reserve suggests that patients with SSc, without overt cardiac or respiratory disease, present with cardiovascular limitation to exercise. This may be related to latent cardiac dysfunction or pulmonary vascular disease.

Acknowledgement/Funding

This work was partially funded by research grants from GSK, Actelion, and from the Belgian Foundation for Cardiac Surgery.

Decreased pulmonary vascular distensibility in adolescents conceived by in vitro fertilization

STUDY QUESTION

What is the functional relevance of decreased pulmonary vascular distensibility in adolescents conceived by IVF?

SUMMARY ANSWER

Children born by IVF have a slight decrease in pulmonary vascular distensibility observed during normoxic exercise that is not associated with altered right ventricular function and aerobic exercise capacity.

WHAT IS KNOWN ALREADY

General vascular dysfunction and increased hypoxic pulmonary hypertension have been reported in ART children as compared to controls. Pulmonary hypertension or decreased pulmonary vascular distensibility may affect right ventricular function and thereby possibly limit maximal cardiac output and aerobic exercise capacity.

STUDY DESIGN, SIZE, DURATION

This prospective case-control study enrolled 15 apparently healthy adolescents conceived by IVF/ICSI after fresh embryo transfer paired in a 2 to 1 ratio to 30 naturally conceived adolescents between March 2015 and May 2018.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Fifteen IVF/ICSI adolescents and 30 controls from singleton gestations matched by age, gender, weight, height and physical activity underwent exercise echocardiography, lung diffusion capacity measurements and a cycloergometer cardiopulmonary exercise test. A pulmonary vascular distensibility coefficient α was determined from the pulmonary arterial pressure (PAP) versus cardiac output (Q) relationships. Pulmonary capillary volume (Vc) was calculated from single breath nitric oxide and carbon monoxide lung diffusion capacity measurements (DLCO and DLNO) at rest and during exercise (100 W). Eight of the IVF subjects and eight controls underwent a 30 min hypoxic challenge at rest with a fraction of inspired oxygen of 0.12 to assess hypoxic pulmonary vasoconstriction.

MAIN RESULTS AND THE ROLE OF CHANCE

In normoxia, oxygen uptake (VO2), blood pressure, DLCO, DLNO, echocardiographic indices of right ventricular function, Q and PAP at rest and during exercise were similar in both groups. However, IVF children had a lower pulmonary vascular distensibility coefficient α (1.2 ± 0.3 versus 1.5 ± 0.3%/mmHg, P = 0.02) and a blunted exercise-induced increase in Vc (24 versus 32%, P < 0.05). Hypoxic-induced increase in pulmonary vascular resistance in eight IVF subjects versus eight controls was similar.

LIMITATIONS, REASONS FOR CAUTION

The IVF cohort was small, and thus type I or II errors could have occurred in spite of careful matching of each case with two controls. ART evolved over the years, so that it is not certain that the presently reported subtle changes will be reproducible in the future. As the study was limited to singletons born after fresh embryo transfers, our observations cannot be extrapolated to singletons born after frozen embryo transfer.

WIDER IMPLICATIONS OF THE FINDINGS

The present study suggests that adolescents conceived by IVF have preserved right ventricular function and aerobic exercise capacity despite a slight alteration in pulmonary vascular distensibility as assessed by two entirely different methods, i.e. exercise echocardiography and lung diffusing capacity measurements. However, the long-term prognostic relevance of this slight decrease in pulmonary vascular distensibility needs to be evaluated in prospective large scale and long-term outcome studies.

STUDY FUNDING/COMPETING INTEREST(S)

Dr Caravita was supported by an ERS PAH short term research training fellowship (STRTF2014-5264). Dr Pezzuto was funded by an Italian Society of cardiology grant. Dr Motoji was supported by a grant from the Cardiac Surgery Funds, Belgium. All authors have no conflicts of interests to declare.

Differentiation of photoreceptors in cultured optic vesicles from embryos of Rana esculenta

Optic vesicles from embryos of Rana esculenta at a stage corresponding to stage 19 in the development of Rana pipiens were cultured for 15 days. The eyes which differentiated in vitro were much smaller than controls of the same age, due partly to the absence of the vitreous body. In many specimens a well-stratified retina surrounded by a layer of pigmented cells was found. The features of all the components of the retinal layers are described.

The complete differentiation of photoreceptors, including their outer segments, is the most interesting result obtained in these organ cultures, and is in contrast with the observations previously reported for retinal tissue cultures. The authors suggest that the source of the material (amphibia instead of birds or mammals) is the main reason for this discrepancy. Frog embryo cells are practically self-sufficient since they are endowed with nutritional substances, amongst which Vit. A and antioxidative agents (Vit. E and ascorbic acid) have been indicated as the most important factors for the structural organization and integrity of the outer segments. The role played by the pigment epithelium is also discussed.

Differentiation of photoreceptors in cultured optic vesicles from embryos of Rana esculenta

Optic vesicles from embryos of Rana esculenta at a stage corresponding to stage 19 in the development of Rana pipiens were cultured for 15 days. The eyes which differentiated in vitro were much smaller than controls of the same age, due partly to the absence of the vitreous body. In many specimens a well-stratified retina surrounded by a layer of pigmented cells was found. The features of all the components of the retinal layers are described. The complete differentiation of photoreceptors, including their outer segments, is the most interesting result obtained in these organ cultures, and is in contrast with the observations previously reported for retinal tissue cultures. The authors suggest that the source of the material (amphibia instead of birds or mammals) is the main reason for this discrepancy. Frog embryo cells are practically self-sufficient since they are endowed with nutritional substances, amongst which Vit. A and antioxidative agents (Vit. E and ascorbic acid) have been indicated as the most important factors for the structural organization and integrity of the outer segments. The role played by the pigment epithelium is also discussed.