Soluble ST2 as a Potential Biomarker for Risk Assessment of Pulmonary Hypertension in Patients Undergoing TAVR?

Novel Biomarkers and Advanced Cardiac Imaging in Aortic Stenosis: Old and New

Currently, the symptomatic status and left ventricular ejection fraction (LVEF) play a crucial role in aortic stenosis (AS) assessment. However, the symptoms are often subjective, and LVEF is not a sensitive marker of left ventricle (LV) decompensation. Over the past years, the cardiac structure and function research on AS has increased due to advanced imaging modalities and potential therapies. New imaging parameters emerged as predictors of disease progression in AS. LV global longitudinal strain has proved useful for risk stratification in asymptomatic severe AS patients with preserved LVEF. The assessment of myocardial fibrosis by cardiac magnetic resonance is the most studied application and offers prognostic information on AS. Moreover, the usage of biomarkers in AS as objective measures of LV decompensation has recently gained more interest. The present review focuses on the transition from compensatory LV hypertrophy (H) to LV dysfunction and the biomarkers associated with myocardial wall stress, fibrosis, and myocyte death. Moreover, we discuss the potential impact of non-invasive imaging parameters for optimizing the timing of aortic valve replacement and provide insight into novel biomarkers for possible prognostic use in AS. However, data from randomized clinical trials are necessary to define their utility in daily practice.

68Ga-labeled WVP peptide as a novel PET probe for molecular biological diagnosis of unstable thoracic aortic aneurysm and early dissection: an animal study

Objective

Type IV collagen (Col-IV) is a prospective biomarker for diagnosing and treating of unstable thoracic aortic aneurysm and dissection (TAAD). This study aims to evaluate the feasibility of ⁶⁸Ga-labeled WVP peptide (⁶⁸Ga-DOTA-WVP) as a novel Col-IV-targeted probe for TAAD biological diagnosis using PET/CT.

Methods

WVP peptide was modified with bifunctional chelator DOTA for ⁶⁸Ga radiolabeling. Immunohistochemical staining was used to evaluate the expression and location of Col-IV and elastin in aortas treated with 3-aminopropionitrile fumarate (BAPN) at different time points (0, 2, and 4 weeks). The imaging performance of ⁶⁸Ga-DOTA-WVP was investigated using Micro-PET/CT in a BAPN-induced TAAD mouse model. The relationship between ⁶⁸Ga-DOTA-WVP uptake in aortic lesions and the serum levels of TAAD-related biomarkers including D-dimer, C-reactive protein (CRP), and serum soluble suppression of tumorigenicity-2 (sST2) was also analyzed.

Results

⁶⁸Ga-DOTA-WVP was readily prepared with high radiochemical purity and stability in vitro. ⁶⁸Ga-DOTA-WVP Micro-PET/CT could detect Col-IV exposure of unstable aneurysms and early dissection in BAPN-induced TAAD mice, but little ⁶⁸Ga-DOTA-WVP uptake was shown in the control group at each imaging time point. The differences of Col-IV expression and distribution of ⁶⁸Ga-DOTA-WVP both in TAAD and control groups further verified the imaging efficiency of ⁶⁸Ga-DOTA-WVP PET/CT. Additionally, a higher sST2 level was found in the imaging positive (n = 14) than the negative (n = 8) group (9.60 ± 1.14 vs. 8.44 ± 0.52, P = 0.014).

Conclusion

⁶⁸Ga-DOTA-WVP could trace the exposure and abnormal deposition of Col-IV in enlarged and early injured aortas, showing a potential for biological diagnosis, whole-body screening, and progression monitoring of TAAD.

A Story of PA/BSA and Biomarkers to Diagnose Pulmonary Hypertension in Patients with Severe Aortic Valve Stenosis-The Rise of IGF-BP2 and GDF-15

(1) Background: Currently, echocardiography is the primary non-invasive diagnostic method used to screen patients with severe aortic valve stenosis (AS) for pulmonary hypertension (PH) by estimating systolic pulmonary artery pressure (sPAP). Other radiological methods have been a focus of research in the past couple of years, as it was shown that by determining the pulmonary artery (PA) diameter, prognostic statements concerning overall mortality could be made in these patients. This study compared established and novel cardiovascular biomarkers with the PA/BSA value to detect PH in patients with severe AS. (2) Methods: The study cohort comprised 188 patients with severe AS undergoing transcatheter aortic valve replacement (TAVR), who were then divided into two groups based on PA/BSA values obtained through CT-angiography. The presence of PH was defined as a PA/BSA ≥ 16.6 mm/m2 (n = 81), and absence as a PA/BSA < 16.6 mm/m2 (n = 107). Blood samples were taken before TAVR to assess cardiovascular biomarkers used in this study, namely brain natriuretic peptide (BNP), cardiac troponin I (cTnI), high-sensitive troponin (hsTN), soluble suppression of tumorigenesis-2 (sST2), growth/differentiation factor 15 (GDF-15), heart-type fatty acid-binding protein (H-FABP), insulin-like growth factor binding protein 2 (IGF-BP2), and soluble urokinase-type plasminogen activator receptor (suPAR). (3) Results: Patients with a PA/BSA ≥ 16.6 mm/m2 showed significantly higher levels of BNP (p = <0.001), GDF-15 (p = 0.040), and H-FABP (p = 0.007). The other investigated cardiovascular biomarkers did not significantly differ between the two groups. To predict a PA/BSA ≥ 16.6 mm/m2, cut-off values for the biomarkers were calculated. Here, GDF-15 (p = 0.029; cut-off 1172.0 pg/mL) and BNP (p < 0.001; cut-off 2194.0 pg/mL) showed significant results. Consequently, analyses of combined biomarkers were performed, which yielded IGF-BP2 + BNP (AUC = 0.721; 95%CI = 0.585−0.857; p = 0.004) as the best result of the two-way analyses and GDF-15 + IGF-BP2 + BNP (AUC = 0.727; 95%CI = 0.590−0.864; p = 0.004) as the best result of the three-way analyses. No significant difference regarding the 1-year survival between patients with PA/BSA < 16.6 mm/m2 and patients with PA/BSA ≥ 16.6 mm/m2 was found (log-rank test: p = 0.452). (4) Conclusions: Although PA/BSA aims to reduce the bias of the PA value caused by different body compositions and sizes, it is still a controversial parameter for diagnosing PH. Combining the parameter with different cardiovascular biomarkers did not lead to a significant increase in the diagnostic precision for detecting PH in patients with severe AS.

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.