Determinants of pulmonary hypertension development in moderate or severe aortic stenosis

Non-invasive imaging techniques for early diagnosis of bilateral cardiac dysfunction in pulmonary hypertension: current crests, future peaks

Pulmonary arterial hypertension (PAH) is a chronic and progressive disease that eventually leads to heart failure (HF) and subsequent fatality if left untreated. Right ventricular (RV) function has proven prognostic values in patients with a variety of heart diseases including PAH. PAH is predominantly a right heart disease; however, given the nature of the continuous circulatory system and the presence of shared septum and pericardial constraints, the interdependence of the right and left ventricles is a factor that requires consideration. Accurate and timely assessment of ventricular function is very important in the management of patients with PAH for disease outcomes and prognosis. Non-invasive modalities such as cardiac magnetic resonance (CMR) and echocardiography (two-dimensional and three-dimensional), and nuclear medicine, positron emission tomography (PET) play a crucial role in the assessment of ventricular function and disease prognosis. Each modality has its own strengths and limitations, hence this review article sheds light on (i) ventricular dysfunction in patients with PAH and RV-LV interdependence in such patients, (ii) the strengths and limitations of all available modalities and parameters for the early assessment of ventricular function, as well as their prognostic value, and (iii) lastly, the challenges faced and the potential future advancement in these modalities for accurate and early diagnosis of ventricular function in PAH.

CT measured pulmonary artery to ascending aorta ratio stratified by echocardiographically obtained systolic pulmonary artery pressure values for noninvasive detection of pulmonary hypertension in patients with severe aortic valve stenosis

BACKGROUND

Transthoracic echocardiography (TTE) offers a measurement method for the determination of pulmonary hypertension (PH) in patients with severe aortic valve stenosis (AS) with determination of maximal tricuspid regurgitation velocity (TRVmax) and systolic pulmonary artery pressure (sPAP). Radiological parameters for noninvasive detection of PH, most importantly computed tomography (CT) based PA/AA-ratio = ratio of pulmonary artery diameter (PA) and ascending aorta diameter (AA), are also included in the latest ESC guidelines. The aim of the present study was to define cut-off values for PA/AA-ratio taking also into account cardiovascular biomarkers to determine criteria for noninvasive diagnosis of PH.

METHODS

194 patients with severe AS undergoing transcatheter aortic valve replacement (TAVR) underwent pre-procedural TTE and CT with measurement of PA/AA-ratio. Additionally, common cardiovascular biomarkers were determined.

RESULTS

TAVR patients with an sPAP ≥ 40 mmHg or a TRVmax ≥ 2.9 m/s had a PA/AA-ratio ≥ 0.80 in an AUROC analysis. The cut-off value of ≥ 0.80 resulted in a significantly higher mortality rate (log-rank test: p = 0.034) in these patients in a Kaplan-Meier analysis regarding 1-year survival after TAVR. Significant differences in biomarker expression between patients with a PA/AA-ratio ≥ 0.80 or < 0.80 occurred for BNP (p = 0.001), cTnI (p = 0.032), GDF-15 (p = 0.002) and H-FABP (p = 0.015).

CONCLUSION

PA/AA-ratio ≥ 0.80 is a promising radiological parameter that can provide information about mortality in patients with severe AS undergoing TAVR; combined with biomarkers it may contribute to noninvasive detection of PH in patients with severe AS.

Right ventricle to pulmonary artery coupling after transcatheter aortic valve implantation-Determinant factors and prognostic impact

Introduction

Right ventricular (RV) dysfunction and pulmonary hypertension (PH) have been previously associated with unfavorable outcomes in patients with severe aortic stenosis (AS) undergoing transcatheter aortic valve implantation (TAVI), but little is known about the effect of right ventricle (RV) to pulmonary artery (PA) coupling. Our study aimed to evaluate the determinant factors and the prognostic value of RV-PA coupling in patients undergoing TAVI.

Methods

One hundred sixty consecutive patients with severe AS were prospectively enrolled, between September 2018 and May 2020. They underwent a comprehensive echocardiogram before and 30 days after TAVI, including speckle tracking echocardiography (STE) for myocardial deformation analysis of the left ventricle (LV), left atrium (LA), and RV function. Complete data on myocardial deformation was available in 132 patients (76.6 ± 7.5 years, 52.5% men) who formed the final study population. The ratio of RV free wall longitudinal strain (RV-FWLS) to PA systolic pressure (PASP) was used as an estimate of RV-PA coupling. Patients were analyzed according to baseline RV-FWLS/PASP cut-off point, determined through time-dependent ROC curve analysis, as follows: normal RV-PA coupling group (RV-FWLS/PASP ≥0.63, n = 65) and impaired RV-PA coupling group (RV-FWLS/PASP < 0.63, n = 67).

Results

A significant improvement of RV-PA coupling was observed early after TAVI (0.75 ± 0.3 vs. 0.64 ± 0.3 before TAVI, p < 0.001), mainly due to PASP decrease (p < 0.001). LA global longitudinal strain (LA-GLS) is an independent predictor of RV-PA coupling impairment before and after TAVI (OR = 0.837, p < 0.001, OR = 0.848, p < 0.001, respectively), while RV diameter is an independent predictor of persistent RV-PA coupling impairment after TAVI (OR = 1.174, p = 0.002). Impaired RV-PA coupling was associated with a worse survival rate (66.3% vs. 94.9%, p-value < 0.001) and emerged as an independent predictor of mortality (HR = 5.97, CI = 1.44-24.8, p = 0.014) and of the composite endpoint of death and rehospitalization (HR = 4.14, CI = 1.37-12.5, p = 0.012).

Conclusion

Our results confirm that relief of aortic valve obstruction has beneficial effects on the baseline RV-PA coupling, and they occur early after TAVI. Despite significant improvement in LV, LA, and RV function after TAVI, RV-PA coupling remains impaired in some patients, it is mainly related to persistent pulmonary hypertension and is associated with adverse outcomes.

The association of left ventricular histologically verified myocardial fibrosis with pulmonary hypertension in severe aortic stenosis

OBJECTIVES

To evaluate the association between histologically verified left ventricular (LV) myocardial fibrosis (MF) and its bio- and functional markers with pulmonary hypertension (PH) in severe aortic stenosis (AS).

METHODS

About 34 patients with isolated severe AS underwent 2D echocardiography, cardiac magnetic resonance (CMR) imaging, and plasma NT-proBNP evaluation before aortic valve replacement (AVR). LV measurements were analyzed by CMR and LV strain using feature tracking software (Medis Suite QStrain 2.0). Myocardial biopsy sampled at the time of AVR was assessed by a histomorphometric analysis. PH was defined as pulmonary artery systolic pressure (PASP) ⩾ 45 mm Hg.

RESULTS

Patients with severe AS and PH (mean PASP 53 ± 3.7 mm Hg) had higher extent of diffuse MF versus patients without PH (12 (10.4-12.7)% vs 6.6 (4.6-8.2)% (p = 0.00)). The extent of diffuse MF correlated with LV dilatation (r = 0.7, p = 0.02), indices of LV dysfunction (lower ejection fraction (r = -0.6, p < 0.001), global longitudinal (r = -0.5, p = 0.02) and circumferential strain (r = -0.5, p = 0.05), elevated NT-proBNP (r = 0.5, p = 0.005) and elevated PASP (r = 0.6, p < 0.001)). Histological MF > 10% (AUC 94.9%), LV global longitudinal strain > -15.5% (AUC 86.3%), and NT-proBNP > 2090 ng/l (AUC 85.1%) were independent predictors of PH in severe AS.

CONCLUSIONS

The extent of diffuse myocardial fibrosis in combination with reduced longitudinal left ventricular strain and increased plasma levels of NT-proBNP relates to pulmonary hypertension in severe aortic stenosis.

How Do Cardiovascular Biomarkers Behave in Patients with Severe Aortic Valve Stenosis with and without Echocardiographically Proven Pulmonary Hypertension?—A Retrospective Study of Biomarker Trends before and after Transcatheter Aortic Valve Replacement

Background: Since right heart catheterization is rarely performed in patients with severe aortic valve stenosis (AS), echocardiography is currently the tool of choice to determine the presence or absence of pulmonary hypertension (PH). The systolic pulmonary artery pressure (sPAP) has established itself as a reliable measurement value for this purpose. The aim of our study was to evaluate the behavior of plasma-level concentrations of novel cardiovascular biomarkers (sST2, GDF-15, H-FABP, IGF-BP2, and suPAR) in patients with severe AS and an sPAP < 40 mmHg in comparison to patients with an sPAP ≥ 40 mmHg before transcatheter aortic valve replacement (TAVR) and after TAVR (24 h, 96 h, 3 months, and 12 months). Methods: We retrospectively separated 85 patients with echocardiographic evidence of severe AS before TAVR procedure into two groups based on sPAP level. An sPAP of 40 mmHg was considered the cut-off value, with the absence of PH defined by an sPAP < 40 mmH (n = 32) and the presence of PH defined by an sPAP ≥ 40 mmHg (n = 53). Blood samples were drawn from each patient one day before TAVR and 24 h, 96 h, 3 months, and 12 months after TAVR. Plasma concentrations of the cardiovascular biomarkers sST2, GDF-15, H-FABP, IGF-BP2, and suPAR were determined and analyzed with univariate and multivariate binary logistic regression and AUROC curves. Results: Patients with severe AS and an sPAP ≥ 40 mmHg had significantly higher plasma concentrations of H-FABP (baseline: p = 0.022; 24 h: p = 0.012; 96 h: p = 0.037; 3 months: p = 0.006; 12 months: p = 0.030) and IGF-BP2 (baseline: p = 0.029; 24 h: p = 0.012; 96 h: p = 0.001; 3 months: p = 0.015; 12 months: p = 0.022) before and continuously up to 12 months after TAVR than did patients with an sPAP < 40 mmHg sST2, with the exception of the 12-month follow-up. We also consistently found significantly higher plasma concentrations in the sPAP ≥ 40 mmHg group (baseline: p = 0.007; 24 h: p = 0.006; 96 h: p = 0.014; 3 months: p ≤ 0.001; 12 months: p = 0.092), whereas suPAR had significantly elevated values at baseline and after 24 h in patients with echocardiographic evidence of PH and significantly decreased values after 3 months (baseline: p = 0.003; 24 h p = 0.041; 96 h: p = 0.127; 3 months: p = 0.006; 12 months: p = 0.477). Plasma concentrations of GDF-15 were only significantly different after 24 h (baseline: p = 0.075; 24 h: p = 0.016; 96 h: p = 0.101; 3 months: p = 0.244; 12 months: p = 0.090). In a multivariate binary logistic regression, atrial fibrillation, tricuspid annular plane systolic excursion (TAPSE), and sST2 at baseline were found to have a significant p-value < 0.050. Conclusion: In this descriptive study, sST2, H-FABP, and IGF-BP2 emerged as the cardiovascular biomarkers with the greatest potential with respect to echocardiographically PH detection in long-term follow-up after TAVR, as patients with an sPAP ≥ 40 mmHg had significantly continuously higher plasma biomarker concentrations than the corresponding cohort did, with an sPAP < 40 mmHg.

Severe Aortic Valve Stenosis and Pulmonary Hypertension: A Systematic Review of Non-Invasive Ways of Risk Stratification, Especially in Patients Undergoing Transcatheter Aortic Valve Replacement

Patients with severe aortic valve stenosis and concomitant pulmonary hypertension show a significantly reduced survival prognosis. Right heart catheterization as a preoperative diagnostic tool to determine pulmonary hypertension has been largely abandoned in recent years in favor of echocardiographic criteria. Clinically, determination of echocardiographically estimated systolic pulmonary artery pressure falls far short of invasive right heart catheterization data in terms of accuracy. The aim of the present systematic review was to highlight noninvasive possibilities for the detection of pulmonary hypertension in patients with severe aortic valve stenosis, with a special focus on cardiovascular biomarkers. A total of 525 publications regarding echocardiography, cardiovascular imaging and biomarkers related to severe aortic valve stenosis and pulmonary hypertension were analyzed in a systematic database analysis using PubMed Central®. Finally, 39 publications were included in the following review. It was shown that the current scientific data situation, especially regarding cardiovascular biomarkers as non-invasive diagnostic tools for the determination of pulmonary hypertension in severe aortic valve stenosis patients, is poor. Thus, there is a great scientific potential to combine different biomarkers (biomarker scores) in a non-invasive way to determine the presence or absence of PH.

Determinants of changes in pulmonary artery pressure in patients with severe aortic stenosis treated by transcatheter aortic valve implantation

BACKGROUND

Elevated pulmonary artery pressure (PAP) in patients with severe aortic stenosis (AS) is a strong predictor of adverse prognosis. This study sought to assess the relation between PAP and clinical and echocardiographic parameters in elderly patients with severe AS, as well as to identify the determinants of the change in PAP after transcatheter aortic valve implantation (TAVI).

METHODS

The study included 170 subjects (age 81 ± 7 years, 45% men) with symptomatic severe AS who were treated by TAVI. They underwent a clinical evaluation and a transthoracic echocardiography before the TAVI procedure and 6 months after.

RESULTS

In a multivariable analysis, the independent predictors for baseline PAP were the body mass index (BMI) (β = 0.21, p = .006), COPD GOLD class (β = 0.20; p = .009), the E/e' ratio (β = 0.20; p = .02) and the degree of aortic regurgitation (β = 0.20; p = .01). After TAVI, there was significantly less (51% vs. 29%, p<.0001) pulmonary hypertension, defined as a tricuspid regurgitation velocity ≥2.8 m/s. The baseline variables related to an improvement in PAP were the tricuspid regurgitation velocity (p = .0001) and the E/e' (p = .005). From the parameters potentially modified with TAVI, the only independent predictor of PAP variation was the change in the E/e' ratio (β = 0.23; p = .01).

CONCLUSIONS

Independent predictors for baseline PAP in elderly patients with symptomatic AS were the BMI, GOLD class, the aortic regurgitation and the E/e' ratio. The baseline predictors for a change in PAP 6 months after TAVI were the baseline PAP and E/e', with only the change in the E/e' ratio being correlated to the change in PAP.

Left Ventricular Morphology and Function as a Determinant of Pulmonary Hypertension in Patients with Severe Aortic Stenosis: Cardiovascular Magnetic Resonance Imaging Study

Background and Objectives: The influence of cardiac magnetic resonance (CMR) derived left ventricular (LV) parameters on the prognosis of patients with aortic stenosis (AS) was analyzed in several studies. However, the data on the relations between the LV parameters and the development of pulmonary hypertension (PH) in severe AS is lacking. Our objectives were to evaluate the CMR-derived changes of the LV size, morphology, and function in patients with isolated severe AS and PH, and to investigate the prognostic impact of these parameters on elevated systolic pulmonary artery pressure (sPAP). Materials and Methods: Thirty patients with isolated severe AS (aortic valve area ≤1 cm²) underwent a 2D-echocardiography (2D echo) and CMR before aortic valve replacement. Indices of the LV mass and volumes and ejection fraction were analyzed by CMR. The LV global longitudinal (LV LGS) and circumferential strain (LV CS) were calculated using CMR feature tracking (CMR-FT) software (Medis Suite QStrain 2.0, Medis Medical Imaging Systems B.V., Leiden, The Netherlands). The LV fibrosis expansion was assessed using a late gadolinium enhancement sequence. PH was defined as having an estimated sPAP of ≥45 mm Hg. The statistical analysis as performed using SPSS version 23.0 (SPSS, Chicago, IL, USA) Results: 30 patients with severe AS were included in the study, 23% with severe isolated AS had PH (mean sPAP 55 ± 6.6 mm Hg). More severe LV anatomical and functional abnormalities were observed in patients with PH when compared with patients without PH-a higher LV end-diastolic volume index (EDVi) (140 [120.0-160.0] vs. 90.0 mL/m² [82.5-103.0], p = 0.04), larger LV fibrosis area (7.8 [5.6-8.0] vs. 1.3% [1.2-1.5], p = 0.005), as well as lower LV global longitudinal strain (GLS; -14.0 [-14.9-(-8.9)] vs. -21.1% [-23.4-(-17.8)], p = 0.004). By receiver-operating characteristic (ROC) curve analysis, LV EDVi > 107.7 mL/m² (Area Under the Curve (AUC) 95.7%), LV GLS < -15.5% (AUC 86.3%), and LV fibrosis area >5% (AUC 89.3) were found to be robust predictors of PH in severe AS patients. Conclusions: In patients with severe aortic stenosis, a larger end-diastolic LV volume, impaired LV global longitudinal strain, and larger LV fibrosis extent can predict the development of pulmonary hypertension.

Impact of Left Ventricular Diastolic Dysfunction and Biomarkers on Pulmonary Hypertension in Patients with Severe Aortic Stenosis

Background: Severe aortic stenosis (AS) complicated by pulmonary hypertension (PH) is associated with poor outcomes after surgical aortic valve replacement (AVR). There is still scarce information about predictors of secondary PH in this group of patients. Objectives: The aim of this study was to investigate the prognostic impact of biomarkers together with conventional Doppler echocardiographic parameters of left ventricular diastolic function on elevated pulmonary systolic pressure (PSP) in severe AS patients before surgical AVR. Methods: Sixty patients with severe isolated AS (aortic valve area <1 cm²) underwent echocardiography, N-terminal pro B-type natriuretic peptide (NT-proBNP) and growth differentiation factor-15 (GDF-15) measurements before AVR. PSP, left ventricular ejection fraction (LV EF), parameters of LV diastolic function (E/E’ ratio, mitral valve deceleration time (MV DT) and left atrial (LA) volume) were evaluated. PH was defined as an estimated PSP ≥ 45 mmHg. Results: Of the 60 patients, 21.7% with severe isolated AS had PH with PSP ≥ 45 mmHg (58.5 ± 11.2 mmHg). LV EF did not differ between groups and was not related to an elevated PSP (50 ± 8 vs. 49 ± 8%, p = 0.58). Parameters of LV diastolic dysfunction (E/E’ ratio > 14 (OR 6.00; 95% CI, 1.41–25.48; p = 0.009), MV DT ≤ 177.5 ms (OR 9.31; 95% CI, 2.06–41.14; p = 0.001), LA volume > 100 mL (OR 9.70; 95% CI, 1.92–49.03; p = 0.002)) and biomarkers (NT-proBNP > 4060 ng/L (OR 12.54; 95% CI, 2.80–55.99; p < 0.001) and GDF-15 > 3393 pg/mL (OR 18.33; 95% CI, 2.39–140.39; p = 0.001)) were significantly associated with elevated PSP in severe AS. Conclusions: Left ventricular diastolic dysfunction and elevated biomarkers levels could predict the development of pulmonary hypertension in patients with severe aortic stenosis. Elevation of biomarkers paired with worsening of LV diastolic dysfunction could help to stratify patients for earlier surgical treatment before the development of pulmonary hypertension.

Left atrial dysfunction as a determinant of pulmonary hypertension in patients with severe aortic stenosis and preserved left ventricular ejection fraction

In patients with severe aortic stenosis (AS), the presence of pulmonary hypertension (PH) has been linked to a poor prognosis. We aimed to assess the main determinants of PH in patients with severe AS and preserved left ventricular ejection fraction (LVEF). We prospectively enrolled 108 consecutive patients with isolated severe AS (indexed aortic valve area <0.6 cm²/m²) and LVEF >50%, in sinus rhythm. Left atrial (LA) function was assessed using longitudinal deformation parameters (by speckle tracking echocardiography). PH (defined as systolic pulmonary artery pressure >40 mmHg) was present in 20 patients. Patients with severe AS and PH were older (p = 0.05), had higher BNP values (p = 0.05) and a greater degree of LV diastolic dysfunction: higher E/e' and E/A ratios and lower EDT values (p < 0.03 for all) compared to patients without PH. There were no differences between groups regarding AS severity and LV systolic function parameters. Patients with PH had a more impaired LA function: lower septal and lateral late diastolic peak velocity a' (p < 0.001 and p = 0.04 respectively) and lower LA peak longitudinal strain and strain rate parameters (p ≤ 0.005 for all). In multivariable analysis, LA late diastolic longitudinal strain rate was the only independent correlate of PH in our patients (p = 0.04). Patients with isolated severe AS, preserved LVEF and PH had larger LA volumes, a more impaired LA function, and higher LV filling pressures compared to those without PH. LA booster pump function, reflected by late diastolic longitudinal strain rate, emerged as an independent correlate of PH in these patients.

Visual Assessment of Relative Apical Sparing Pattern Is More Useful Than Quantitative Assessment for Diagnosing Cardiac Amyloidosis in Borderline or Mildly Increased Left Ventricular Wall Thickness

BACKGROUND

Relative apical sparing pattern of longitudinal strain (RapSP-LS) was suggested in advanced cardiac amyloidosis (CA). It is unclear whether it is present in less advanced CA.

METHODS AND RESULTS

Patients with presumptive diagnosis of CA and mean left ventricular wall thickness (LVWT) ≤14 mm were recruited. Apart from RapSP-LS visually identified, relative apical longitudinal strain index (RapLSI) was defined as [average apical LS/(average basal LS+average mid-ventricle LS)]. Among 119 patients included, 47 were finally diagnosed with CA. RapLSI was higher in the CA group compared to other causes of increased mean LVWT (P<0.001), but with a significant range of overlap noted. In contrast, RapSP-LS visually assessed was noted in most CA patients (31/47, 66.0%) except in those with preserved LV ejection fraction, normal LVWT, and mildly decreased global LS, suggesting least advanced CA. On multivariate analysis of the added diagnostic role of RapSP-LS or RapLSI on top of clinical, electrocardiographic, and conventional echocardiographic parameters, addition of RapLSI produced only borderline increase in area under the curve of the multivariate model (P=0.05), whereas addition of RapSP-LS significantly increased it (P<0.001).

CONCLUSIONS

Visual identification of RapSP-LS is useful in terms of added diagnostic value compared with quantitative calculation of RapLSI. Its clinical application, however, should be used with caution in patients with less advanced CA.