A streamlined, machine learning-derived approach to risk-stratification in heart failure patients with secondary tricuspid regurgitation

Background

Secondary tricuspid regurgitation (sTR) is the most frequent valvular heart disease and has significant impact on mortality. A high burden of comorbidities often worsens the already dismal prognosis of sTR, while tricuspid interventions remain underused and initiated too late.

Objectives

To examine the most powerful predictors of all-cause mortality in moderate and severe sTR using machine learning techniques and to provide a streamlined approach to risk-stratification using readily available clinical, echocardiographic and laboratory parameters.

Methods

This large-scale, long-term observational study included 3359 moderate and 1509 severe sTR patients encompassing the entire heart failure spectrum (preserved, mid-range and reduced ejection fraction). A random survival forest was applied to investigate the most important predictors and group patients according to their number of adverse features (Figure 1).

Results

The identified predictors and thresholds, that were associated with significantly worse mortality were higher age (≥75 in moderate and ≥70 years in moderate and severe sTR respectively), higher NT-proBNP (≥4000 pg/ml), increased high sensitivity C-reactive protein (≥1.0 mg/dl), serum albumin <40 g/L and hemoglobin <13 g/dL. Additionally, grouping patients according to the number of adverse features yielded important prognostic information, as patients with 4 or 5 adverse features had a sevenfold risk increase in moderate sTR (7.11 [2.27–4.30] HR 95% CI, P<0.001) and fivefold risk increase in severe sTR (5.08 [3.13–8.24] HR 95% CI, P<0.001) (Figure 2: A moderate sTR derivation, B moderate sTR validation, C severe sTR derivation, D severe sTR validation).

Conclusion

This study presents a streamlined, machine learning-derived and internally validated approach to risk-stratification in patients with moderate and severe sTR, that adds important prognostic information to aid clinical decision-making.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Austrian Science Fund

Life expectancy and early to mid-term dysfunction of transcatheter aortic prostheses: incidence, modes, correlates, and outcome

Backgrounds

Bioprosthetic valve dysfunction (BVD) is a major concern regarding transcatheter aortic valve implantation (TAVI) in low-risk patients.

Aims

To assess incidence, determinants, modes, and outcome of early to mid-term BVD after TAVI in relation with life expectancy.

Methods

Consecutive TAVI recipients (2007–2020) with a post-interventional follow-up ≥1-year were prospectively included. BVD components and bioprosthetic valve failure (BVF) were assessed according to updated Valve-Academic-Research-Consortium-3 criteria. Echocardiographic and laboratory follow-up was performed prior to discharge, at 3- and 12-months, and yearly thereafter. BVD/BVF and all-cause death served as endpoints. Average life expectancy was calculated from National Open Health Data and patients were stratified according to tertiles (1st: <6.85y, 2nd: 6.85–9.7y, 3rd: >9.7y).

Results

Of 1047 patients (81.6±6.8 y/o, 52.7% female, EuroSCORE II 4.5±2.5), ≥2 follow-ups were available from 622 (serial echo cohort). After a median echo follow-up of 12.2 months, incidence rates of BVD and BVF were 8.4% [95% confidence interval 6.7–10.3], and 3.5% [2.5–4.9] per valve-year, respectively, without differences between life expectancy tertiles (Figure 1). BVD incidence was double within the first year of implant (9.9% [7.7–12.6] per valve-year; mostly non-structural VD) vs. beyond (4.8% [3.1–7.2] per valve-year; structural and non-structural VD). Valve-in-valve procedure, and stenosis severity (both p<0.05), but not age/life expectancy (p>0.5) predisposed for BVD.

After 4.4±3.0 years, mortality was 36.7%. Time-dependent BVD/BVF were independently associated with outcome for patients in the first (adjusted hazard ratio [AHR] 1.72 [1.06–2.88]/ 2.97 [1.72–6.22]) and second (AHR 1.96 [1.02–3.73]/ 2.31 [1.00–5.30]), but not the third tertile of life expectancy (AHR 1.42 [0.66–3.12]/ 1.84 [0.71–4.79]; Figure 1).

Conclusions

In this large prospective observational cohort, early to mid-term BVD after TAVI occurred at the same rate across the spectrum of life expectancy and was not prognostic among those with the longest life expectancy.

Funding Acknowledgement

Type of funding sources: None.

Cerebral protection in TAVR – can we do without? Impact on stroke rate, length of hospital stay and 12-month mortality

 

Stroke associated with transcatheter aortic valve replacement (TAVR) is a potentially devastating complication. Until recently, the Sentinel™ Cerebral Protection System (CPS; Boston Scientific) has been the only commercially available device for mechanical prevention of TAVR-related stroke. However, its effectiveness is still undetermined.

Methods

Between January 2019 and August 2020 consecutive patients were randomly assigned to TAVR with or without Sentinel™ in a 1:1 fashion. We defined as primary endpoint clinically detectable cerebrovascular events within 72 hours after TAVR, and as secondary endpoints LOS and 12-month mortality. Logistic and linear regression analyses were used to assess associations of Sentinel™ use with endpoints.

Results

Of 411 patients (80±7 y/o, 47.4% female, EuroSCORE II 6.3±5.9%), Sentinel™ was used in 213 (51.8%), with both filters correctly deployed in 189 (46.0%). 20 (4.9%) cerebrovascular events were recorded, 10 (2.4%) of which were disabling strokes. Sentinel™ reduced cerebrovascular events in univariate analysis by 71% (OR 0.29, 95% CI 0.11–0.82; p=0.02) and after multivariate adjustment by 75% (adj. OR 0.25; 95% CI 0.08–0.80; p=0.02). Sentinel™ use was also significantly associated with shorter LOS (8.4±9.6 versus 6.7±6.1 days; p=0.03) and lower 12-month all-cause mortality (15.7% versus 7.5%, p=0.01).

Conclusions

In the present prospective all-comers TAVR cohort, Sentinel™ significantly 1) reduced cerebrovascular events, 2) shortened LOS, and 3) improved 12-month survival. These data promote the use of a CPS when implanting TAVR valves.

Funding Acknowledgement

Type of funding sources: None.

Influence of diabetes, heart failure, and NT-proBNP on cardiovascular outcomes in patients with atrial fibrillation – insights from a cohort study of 7,412 patients with extended follow-up

Background

Diabetes and heart failure (HF) promote atrial fibrillation (AF) and are associated with an increased risk of adverse cardiovascular (CV) events in patients with AF. Because of effective anticoagulation options, AF patients are now more likely to develop HF than a stroke or a systemic embolic event. Appropriate risk stratification of patients with AF should therefore not only consider the risk for stroke but also for HF events.

Methods

Patients with AF admitted to a tertiary academic center between 01/2005 and 07/2019 were identified through a search of electronic health records. The primary outcome of interest was CV death or hospitalization for HF (HHF). We used Cox regression models adjusted for age, sex, estimated glomerular filtration rate, diabetes, HF, body mass index, prior myocardial infarction, hypertension, smoking, C-reactive protein, and LDL-C. To select the most informative variables and overcome the limitations of stepwise regression procedures, we performed a least absolute shrinkage and selection operator logistic regression in a model that incorporated diabetes, HF, NT-proBNP, and the covariates for adjustment in combination with 10-fold cross-validation.

Results

In total, 7,412 patients (median age 70 years, 39.7% female) were included in the present analysis and followed over a median of 4.6 years. Both diabetes (Adjusted (Adj.) hazard ratio (HR) 1.87, 95% confidence interval (CI) 1.55 to 2.25) and HF (Adj. HR 2.57, 95% CI 2.22 to 2.98) were significantly associated with CV death/HHF after multivariable adjustment. Compared to patients with diabetes, HF patients had a higher risk of HHF but a similar risk of CV and all-cause death. There was a robust relationship between CV death/HHF and NT-proBNP (Adj. HR for 1-unit increase in standardized log-transformed biomarker 1.86, 95% CI 1.67 to 2.07). NT-proBNP showed good discriminatory performance (AUC 0.78, 95% CI 0.77–0.80), and the addition of NT-proBNP to the covariates used for adjustment resulted in a significant AUC improvement (Δ=0.04, P<0.001). With least absolute shrinkage and selection operator logistic regression, the strongest associations for CV death/HHF were obtained for NT-proBNP (OR 2.69 per 1-SD in log-transformed biomarker), HF (OR 1.73), and diabetes (OR 1.65).

Conclusion

These findings suggest that the influence of diabetes and HF expand beyond the risk of stroke and systemic embolic events to CV death/HHF in an unselected AF patient population. NT-proBNP may provide improved risk assessment in AF patients.

Funding Acknowledgement

Type of funding sources: None. Figure 1. Forest Plot

Imaging and circulating biomarkers: a united approach for secondary tricuspid regurgitation

Background

Secondary tricuspid regurgitation (STR) is frequent among patients with heart failure with reduced ejection fraction (HFrEF), however inheres considerable diagnostic challenges. The assessment of circulating biomarkers reflecting neurohumoral activation may constitute a valuable supplement to the currently imaging-based diagnostic process. This study therefore sought to investigate (i) the expression of a set of complementary biomarkers in STR, (ii) to evaluate their association with STR severity, and (iii) to analyse whether the combination of neurohormone measurement and echocardiographic grading improves the individual patient risk assessment.

Methods

We included 576 HFrEF patients under guideline-directed therapy recording functional, echocardiographic, invasive hemodynamic and biochemical measurements, i.e. N-terminal pro-B-type natriuretic peptide, mid-regional pro-atrial natriuretic peptide (MR-proANP), mid-regional pro-adrenomedullin, C-terminal pro-endothelin-1 (CT-pro-ET1) and copeptin.

Results

Plasma levels of aforementioned neurohormones were significantly rising with increasing STR severity (for all P<0.001). Among all measured biomarkers, CT-pro-ET1 and MR-proANP were closest related to severe STR, even after multivariate adjustment for established clinical confounders (adj. OR 1.46; 95% CI 1.11–1.91, P=0.006 and adj. OR 1.45, 95% CI 1.13–1.87, P=0.004, respectively). By means of individual outcome in patients with moderate to severe STR, adding the selected biomarkers (i.e. CT-pro-ET1 and MR-proANP) resulted in a substantial improvement in the discriminatory power regarding long-term mortality (C-statistic: 0.54 vs. 0.65, P<0.001; continuous NRI 57%, P<0.001).

Conclusions

Circulating biomarkers closely relate to STR severity and correlate with hemodynamic and morphologic mechanisms of STR. Specifically, MR-proANP and CT-pro-ET1 are closely linked to the presence of severe STR and a combined assessment with the guideline recommended echocardiographic grading leads to a significant improvement of individual risk stratification.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): FWF - Austrian Science Fund Graphical AbstractNeurohumoral profiles of STR

Right ventricular function and outcome in patients undergoing transcatheter aortic valve implantation

Funding Acknowledgements

Type of funding sources: None.

Background. Right ventricular dysfunction (RVD) on echocardiography has been shown to predict outcomes in patients undergoing transcatheter aortic valve implantation (TAVI). However, a comparison with the gold standard, RV ejection fraction (EF) on cardiovascular magnetic resonance (CMR), has never been performed.

Objectives. To compare RV function parameters on echocardiography and CMR for prognostication in TAVI patients.

Methods. Consecutive patients scheduled for TAVI underwent echocardiography and CMR.  RV fractional area change (FAC), TAPSE, RV free-lateral-wall tissue Doppler (S’) and strain were assessed on echocardiography, and RVEF on CMR. Patients were prospectively followed. Adjusted regression analyses were used to report the strength of association per 1-SD decline for each RV function parameter with 1) NT-proBNP levels, 2) prolonged in-hospital stay (>14 days), and 3) a composite of heart failure hospitalization and death.

Results. 204 patients (80.9 ± 6.6y/o; 51% female; EuroSCORE-II: 6.5 ± 5.5%) were included. At a cross-sectional level, all RV function parameters were associated with NT-proBNP levels, but only FAC and RVEF were significantly associated with a prolonged in-hospital stay (adj. OR 1.98 [95%CI: 1.15-3.41], p = 0.013 and 2.29 [95%CI: 1.43-3.67], p = 0.001, respectively). A total of 56 events occurred during follow-up (mean 13.7 ± 9.5months). After adjustment for the EuroSCORE-II and NT-proBNP levels, only RVEF was significantly associated with the composite endpoint (adj. HR 1.69 [95%CI: 1.24-2.30], p < 0.001, Figure 1).

Conclusions. RVD as defined by echocardiography is associated with an advanced disease state, but fails to predict outcomes after adjustment for pre-existing clinical risk factors in TAVI patients. In contrast, RVEF on CMR is independently associated with heart failure hospitalization and death.

Abstract Figure 1. Outcome analysis

552 Natural history of bivalvular functional regurgitation

Introduction

Bivalvular functional regurgitation (BVFR) defined as concomitant mitral and tricuspid insufficiency has not been described or systematically assessed before. The present study therefore sought to define incidence, impact and natural history of BVFR in heart failure with reduced ejection fraction (HFrEF) to provide the foundation for risk assessment and directions for potential treatment strategies.

Methods

We enrolled 1021 consecutive patients with HFrEF under guideline-directed medical therapy and performed comprehensive echocardiographic and neurohumoral profiling. Mitral and tricuspid regurgitation was quantified by an integrated approach comprising valve morphology, width of the proximal regurgitant jet, proximal flow convergence, and pulmonary venous flow. All-cause mortality during a five-year follow up served as the primary endpoint.

Results

Thirty percent of patients suffered from moderate or severe BVFR. Long-term mortality increased with the presence and severity of FR with severe BVFR representing the highest risk-subset (P < 0.001). Severe BVFR patients were more symptomatic and displayed an adverse remodeling and neurohumoral activation pattern (all P < 0.05). Severe BVFR was associated with excess mortality (Figurel 1, Panel A) independently of clinical (adj.HR 1.52, 95%CI 1.39-1.84;P < 0.001) and echocardiographic (adj.HR 1.31, 95%CI 1.11-1.54;P = 0.001) confounders, guideline-directed medical therapy (adj. HR 1.55, 95%CI 1.35-1.79;P < 0.001) and neurohumoral activation (adj.HR 1.31, 95%CI 1.07-1.59;P = 0.009). Moderate BVFR (n = 99) comprised equal baseline characteristics and similar risk as isolated severe FR. (Figure 1, Panel B) (HR 0.95, 95%CI 0.69-1.30;P = 0.73).

Conclusion

This long-term outcome study shows the multi-faceted nature of FR and defines BVFR as an important clinical entity associated with impaired functional class, adverse cardiac remodeling and excess risk of mortality. Moderate BVFR conveys similar risk as isolated severe FR reflecting the deleterious impact of the global regurgitant load on the failing heart and the need of an integrated understanding for risk-assessment.

Abstract 552 Figure 1 (Panel A and B)

P4128The right heart in patients undergoing transcatheter aortic valve replacement: insights from cardiac magnetic resonance imaging

Background

Cardiac magnetic resonance (CMR) provides the gold standard for the assessment of ventricular volumes and mass. However, data on right ventricular systolic dysfunction (RVSD) and its prognostic significance on outcome in patients undergoing transcatheter aortic valve replacement (TAVR) are lacking.

Methods

We consecutively enrolled patients with severe aortic stenosis scheduled for TAVR who underwent preprocedural CMR. Kaplan-Meier estimates and multivariate Cox-regression analysis were used to identify factors associated with outcome, including RVSD. A composite of heart failure hospitalization and/or cardiovascular death was selected as primary study endpoint.

Results

145 consecutive patients (80.5±7.6 years; 51.7% female) were prospectively included, 25 (17.2%) of which had RVSD defined as RV ejection fraction (RVEF) <40%. RVSD was significantly associated with male sex, atrial fibrillation, reduced left ventricular (LV) EF (<50%) and RV endsystolic volume on CMR (all p<0.05). Serum NT-proBNP (14065±12042 vs. 3203±4615 ng/ml; p<0.001) and creatinine levels (1.59±0.96 vs. 1.29±1.03 mg/dl; p=0.201) were elevated in patients with RVSD. A total of 27 events occurred during follow-up (29±13 weeks). While LVSD was not significantly associated with outcome (p=0.654), RVSD showed a strong and independent association with event-free survival in the multivariate Cox-regression analysis [hazard ratio 3.836 (95% confidence interval 1.670–8.810); p=0.002], which included all relevant CMR parameters, cardiovascular risk factors and routine biomarkers.

Conclusions

RVSD rather than LVSD, as determined by CMR, is an important predictor of outcome in patients undergoing TAVR. RV function might thus add useful prognostic information on top of established risk factors.

Pro-oxidant HDL predicts poor outcome in patients with ST-elevation acute coronary syndrome

Oxidative stress affects clinical outcome in patients with ST-elevation acute coronary syndrome (STE-ACS). Although high-density lipoprotein (HDL) particles are generally considered protective, deleterious properties of HDL have been observed in patients with acute myocardial infarction. Here, we analysed the association between pro oxidant HDL and all-cause mortality in STE-ACS patients. We determined the antioxidant function of HDL in 247 prospectively enrolled patients undergoing primary percutaneous coronary intervention for STE-ACS. Patients were stratified as by a pro-oxidant serum HDL oxidant index (HOI 1) or with an antioxidant serum HOI (HOL< 1) capacity. Multivariate regression analysis was used to relate HOI to survival. The median follow-up time was 23 months (IQR 14.4–40.0 months). Pro-oxidant HDL was observed in 44.1 % of STE-ACS patients and was independently associated with all-cause mortality with a hazard ratio of 3.30(95 %CI 1.50–7.27, p = 0.003). Mortality rates were higher in patients with baseline pro-oxidant HDL compared to patients with preserved HDL function at 30 days (11.9 % vs 2.2 %, p=0.002), and at 4 years (22.9 % vs 8.7 %, p=0.002). Elevated neutrophil counts were a strong and independent predictor for pro-oxidant HDL with an odds ratio per standard deviation of 1.50 (95 %CI 1.11–2.03, p=0.008), as was history of prior acute myocardial infarction, elevated triglycerides levels and reduced glomerular filtration rate. In conclusion, pro-oxidant HDL represents a strong and independent predictor of long-term as well as short-term all-cause mortality in STE-ACS patients. Elevated neutrophil counts predicted the presence of serum pro-oxidant HDL. The maintenance of HDL functions might be a promising therapeutic target in STE-ACS patients.

Combined oral administration of L-arginine and tetrahydrobiopterin in a rat model of pulmonary arterial hypertension

Alterations in the nitric oxide (NO) pathway play a major role in pulmonary arterial hypertension (PAH). L-arginine (LA) and tetrahydrobiopterin (BH₄) are main substrates in the production of NO, which mediates pulmonary vasodilation. Administration of either LA or BH₄ decrease pulmonary artery pressure (PAP). A combined administration of both may have synergistic effects in the therapy of PAH. In a telemetrically monitored model of unilateral pneumonectomy and monocrotaline-induced PAH, male Sprague-Dawley rats received either LA (300 mg/kg; n = 15), BH₄ (20 mg/kg; n = 15), the combination of LA and BH₄ (300 mg/kg, 20 mg/kg; n = 15), or vehicle (control group; n = 10) from day 28 after monocrotaline induction. Therapy was orally administered once daily over consecutive 14 days. LA, BH₄, or both equally lowered PAP, increased pulmonary vascular elasticity, restored spontaneous locomotoric activity, prevented body weight loss and palliated small vessel disease of severely pulmonary hypertensive rats. BH₄ substitution lowered asymmetric dimethylarginine levels sustainably at 60 min after administration and downregulated endothelial NO synthase mRNA expression. No significant survival, macro- and histomorphologic or hemodynamic differences were found between therapy groups at the end of the study period. Administration of LA and BH₄ both mediated a decrease of mean PAP, attenuated right ventricular hypertrophy and small vessel disease in monocrotaline-induced pulmonary hypertensive rats, though a combined administration of both substances did not reveal any synergistic therapy effects in our animal model.

Splenectomy is modifying the vascular remodeling of thrombosis

Background

Splenectomy is a clinical risk factor for complicated thrombosis. We hypothesized that the loss of the mechanical filtering function of the spleen may enrich for thrombogenic phospholipids in the circulation, thereby affecting the vascular remodeling of thrombosis.

Methods and Results

We investigated the effects of splenectomy both in chronic thromboembolic pulmonary hypertension (CTEPH), a human model disease for thrombus nonresolution, and in a mouse model of stagnant flow venous thrombosis mimicking deep vein thrombosis. Surgically excised thrombi from rare cases of CTEPH patients who had undergone previous splenectomy were enriched for anionic phospholipids like phosphatidylserine. Similar to human thrombi, phosphatidylserine accumulated in thrombi after splenectomy in the mouse model. A postsplenectomy state was associated with larger and more persistent thrombi. Higher counts of procoagulant platelet microparticles and increased leukocyte–platelet aggregates were observed in mice after splenectomy. Histological inspection revealed a decreased number of thrombus vessels. Phosphatidylserine‐enriched phospholipids specifically inhibited endothelial proliferation and sprouting.

Conclusions

After splenectomy, an increase in circulating microparticles and negatively charged phospholipids is enhanced by experimental thrombus induction. The initial increase in thrombus volume after splenectomy is due to platelet activation, and the subsequent delay of thrombus resolution is due to inhibition of thrombus angiogenesis. The data illustrate a potential mechanism of disease in CTEPH.

Defective angiogenesis delays thrombus resolution: a potential pathogenetic mechanism underlying chronic thromboembolic pulmonary hypertension

OBJECTIVE

Restoration of patency is a natural target of vascular remodeling after venous thrombosis that involves vascular endothelial cells and smooth muscle cells, as well as leukocytes. Acute pulmonary emboli usually resolve <6 months. However, in some instances, thrombi transform into fibrous vascular obstructions, resulting in occlusion of the deep veins, or in chronic thromboembolic pulmonary hypertension (CTEPH). We proposed that dysregulated thrombus angiogenesis may contribute to thrombus persistence.

APPROACH AND RESULTS

Mice with an endothelial cell-specific conditional deletion of vascular endothelial growth factor receptor 2/kinase insert domain protein receptor were used in a model of stagnant flow venous thrombosis closely resembling human deep vein thrombosis. Biochemical and functional analyses were performed on pulmonary endarterectomy specimens from patients with CTEPH, a human model of nonresolving venous thromboembolism. Endothelial cell-specific deletion of kinase insert domain protein receptor and subsequent ablation of thrombus vascularization delayed thrombus resolution. In accordance with these findings, organized human CTEPH thrombi were largely devoid of vascular structures. Several vessel-specific genes, such as kinase insert domain protein receptor, vascular endothelial cadherin, and podoplanin, were expressed at lower levels in white CTEPH thrombi than in organizing deep vein thrombi and organizing thrombi from aortic aneurysms. In addition, red CTEPH thrombi attenuated the angiogenic response induced by vascular endothelial growth factor.

CONCLUSIONS

In the present work, we propose a mechanism of thrombus nonresolution demonstrating that endothelial cell-specific deletion of kinase insert domain protein receptor abates thrombus vessel formation, misguiding thrombus resolution. Medical conditions associated with the development of CTEPH may be compromising early thrombus angiogenesis.