Development and validation of the ASGARD risk score for safe monitoring in asymptomatic nonsevere aortic stenosis.

AIMS: Current guidelines recommend serial echocardiography at minimum 1-2 year intervals for monitoring patients with nonsevere aortic valve stenosis (AS), which is costly and often clinically inconsequential.We aimed to develop and test whether the biomarker-based ASGARD risk score (Aortic Valve Stenosis Guarded by Amplified Risk Determination) can guide the timing of echocardiograms in asymptomatic patients with nonsevere AS. METHODS: The development cohort comprised 1,093 of 1,589 (69%) asymptomatic patients with mild-to-moderate AS who remained event-free one year after inclusion into the SEAS trial. Cox regression landmark analyses with a 2-year follow-up identified the model (ASGARD) with the lowest Akaike information criterion for association to AS-related composite outcome (heart failure hospitalization, aortic valve replacement, or cardiovascular death). Fine-Gray analyses provided cumulative event rates by ASGARD score quartiles. The ASGARD score was internally validated in the remaining 496 patients (31%) from the SEAS-cohort and externally in 71 asymptomatic outpatients with nonsevere AS from six Copenhagen hospitals. RESULTS: The ASGARD score comprises updated measurements of heart rate and age- and sex-adjusted N-terminal pro-brain natriuretic peptide upon transaortic maximal velocity (Vmax) from the previous year. The ASGARD score had high predictive accuracy across all cohorts (external validation: area under the curve: 0.74 [95% CI, 0.62-0.86]), and similar to an updated Vmax measurement. An ASGARD score ≤50% was associated with AS-related event rates ≤5% for a minimum of 15 months. CONCLUSION: The ASGARD score could provide a personalized and safe surveillance alternative to routinely planned echocardiograms, so physicians can prioritize echocardiograms for high-risk patients.

In this study, we developed and examined the potential of the novel ASGARD risk score to tailor personalized follow-up intervals for diagnostic heart scans, incorporating updated heart rate and blood marker measurements along with the heart scan data from the previous year. Patients with the ASGARD risk score within the lowest 50% had a low annual risk of aortic valve-related events (less than 5%) for a minimum of 15 months.In clinical settings, the ASGARD score could provide a personalized and safe monitoring alternative to routine heart scans, prioritizing the diagnostic heart scans for high-risk patients.

Association of high-sensitivity troponin T with outcomes in asymptomatic non-severe aortic stenosis: a post-hoc substudy of the SEAS trial.

Background: High-sensitivity Troponin T (hsTnT), a biomarker of cardiomyocyte overload and injury, relates to aortic valve replacement (AVR) and mortality in severe aortic stenosis (AS). However, its prognostic value remains unknown in asymptomatic patients with AS. We aimed to investigate if an hsTnT level >14 pg/mL (above upper limit of normal 99th percentile) is associated with echocardiographic AS-severity, subsequent AVR, ischaemic coronary events (ICE), and mortality in asymptomatic patients with non-severe AS. Methods: In this post-hoc sub-analysis of the multicentre, randomised, double-blind, placebo-controlled SEAS trial (ClinicalTrials.gov, NCT00092677), we included asymptomatic patients with mild to moderate-severe AS. We ascertained baseline and 1-year hsTnT concentrations and examined the association between baseline levels and the risk of the primary composite endpoint, defined as the first event of all-cause mortality, isolated AVR (without coronary artery bypass grafting (CABG)), or ICE. Multivariable regressions and competing risk analyses examined associations of hsTnT level >14 pg/mL with clinical correlates and 5-year risk of the primary endpoint. Findings: Between January 6, 2003, and March 4, 2004, a total of 1873 patients were enrolled in the SEAS trial, and 1739 patients were included in this post-hoc sub-analysis. Patients had a mean (SD) age of 67.5 (9.7) years, 61.0% (1061) were men, 17.4% (302) had moderate-severe AS, and 26.0% (453) had hsTnT level >14 pg/mL. The median hsTnT difference from baseline to 1-year was 0.8 pg/mL (IQR, -0.4 to 2.3). In adjusted linear regression, log(hsTnT) did not correlate with echocardiographic AS severity (p = 0.36). In multivariable Cox regression, a hsTnT level >14 pg/mL vs. hsTnT ≤14 pg/mL was associated with an increased risk of the primary composite endpoint (HR, 1.41; 95% CI, 1.18-1.70; p = 0.0002). In a competing risk model of first of the individual components of the primary endpoint, a hsTnT level >14 pg/mL was associated with ICE risk (HR 1.71; 95% CI, 1.23-2.38; p = 0.0013), but not with isolated AVR (p = 0.064) or all-cause mortality (p = 0.49) as the first event. Interpretation: hsTnT level is within the reference range (≤14 pg/mL) in 3 out of 4 non-ischaemic patients with asymptomatic mild-to-moderate AS and remains stable during a 1-year follow-up regardless of AS-severity. An hsTnT level >14 pg/mL was mainly associated with subsequent ICE, which suggest that hsTnT concentration is primarily a risk marker of subclinical coronary atherosclerotic disease. Funding: Merck & Co., Inc., the Schering-Plough Corporation, the Interreg IVA program, Roche Diagnostics Ltd., and Gangstedfonden. Open access publication fee funding provided by prof. Olav W. Nielsen and Department of Cardiology, Bispebjerg University Hospital, Denmark.

Association of Annual N-Terminal Pro-Brain Natriuretic Peptide Measurements With Clinical Events in Patients With Asymptomatic Nonsevere Aortic Stenosis: A Post Hoc Substudy of the SEAS Trial.

IMPORTANCE: Recent studies have questioned the presumed low-risk status of patients with asymptomatic nonsevere aortic stenosis (AS). Whether annual N-terminal pro-brain natriuretic peptide (NT-proBNP) measurements are useful for risk assessment is unknown. OBJECTIVE: To assess the association of annual NT-proBNP measurements with clinical outcomes in patients with nonsevere AS. DESIGN, SETTING, AND PARTICIPANTS: Analysis of annual NT-proBNP concentrations in the multicenter, double-blind Simvastatin and Ezetimibe in Aortic Stenosis (SEAS) randomized clinical trial was performed. SEAS was conducted from January 6, 2003, to April 1, 2008. Blood samples were analyzed in 2016, and data analysis was performed from February 10 to October 10, 2021. SEAS included 1873 patients with asymptomatic AS not requiring statin therapy with transaortic maximal flow velocity from 2.5 to 4.0 m/s and preserved ejection fraction. This substudy included 1644 patients (87.8%) with available blood samples at baseline and year 1. EXPOSURES: Increased age- and sex-adjusted NT-proBNP concentrations at year 1 and a 1.5-fold or greater relative NT-proBNP concentration change from baseline to year 1. Moderate AS was defined as baseline maximal flow velocity greater than or equal to 3.0 m/s. MAIN OUTCOMES AND MEASURES: Aortic valve events (AVEs), which are a composite of aortic valve replacement, cardiovascular death, or incident heart failure due to AS progression, were noted. Landmark analyses from year 1 examined the association of NT-proBNP concentrations with outcomes. RESULTS: Among 1644 patients, 996 were men (60.6%); mean (SD) age was 67.5 (9.7) years. Adjusted NT-proBNP concentrations were within the reference range (normal) in 1228 of 1594 patients (77.0%) with NT-proBNP values available at baseline and in 1164 of 1644 patients (70.8%) at year 1. During the next 2 years of follow-up, the AVE rates per 100 patient-years for normal vs increased adjusted NT-proBNP levels at year 1 were 1.39 (95% CI, 0.86-2.23) vs 7.05 (95% CI, 4.60-10.81) for patients with mild AS (P < .01), and 10.38 (95% CI, 8.56-12.59) vs 26.20 (95% CI, 22.03-31.15) for those with moderate AS (P < .01). Corresponding all-cause mortality rates were 1.05 (95% CI, 0.61-1.81) vs 4.17 (95% CI, 2.42-7.19) for patients with mild AS (P < .01), and 1.60 (95% CI, 0.99-2.57) vs 4.78 (95% CI, 3.32-6.87) for those with moderate AS (P < .01). In multivariable Cox proportional hazards regression models, the combination of a 1-year increased adjusted NT-proBNP level and 1.5-fold or greater NT-proBNP level change from baseline was associated with the highest AVE rates in both patients with mild AS (hazard ratio, 8.12; 95% CI, 3.53-18.66; P < .001) and those with moderate AS (hazard ratio, 4.05; 95% CI, 2.84-5.77; P < .001). CONCLUSIONS AND RELEVANCE: The findings of this study suggest that normal NT-proBNP concentrations at 1-year follow-up are associated with low AVE and all-cause mortality rates in patients with asymptomatic nonsevere AS. Conversely, an increased 1-year NT-proBNP level combined with a 50% or greater increase from baseline may be associated with high AVE rates. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT00092677.

Total Center Percutaneous Coronary Intervention Volume and 30-Day Mortality: A Contemporary National Cohort Study of 427 467 Elective, Urgent, and Emergency Cases.

BACKGROUND: The relationship between procedural volume and prognosis after percutaneous coronary intervention (PCI) remains uncertain, with some studies finding in favor of an inverse association and some against. This UK study provides a contemporary reassessment in one of the few countries in the world with a nationally representative PCI registry. METHODS AND RESULTS: A nationwide cohort study was performed using the national British Cardiovascular Intervention Society registry. All adult patients undergoing PCI in 93 English and Welsh NHS hospitals between 2007 and 2013 were analyzed using hierarchical modeling with adjustment for patient risk. Of 427 467 procedures (22.0% primary PCI) in 93 hospitals, 30-day mortality was 1.9% (4.8% primary PCI). 87.1% of centers undertook between 200 and 2000 procedures annually. Case mix varied with center volume. In centers with 200 to 399 PCI cases per year, a smaller proportion were PCI for ST-segment-elevation myocardial infarction (8.4%) than in centers with 1500 to 1999 PCI cases per year (24.2%), but proportionally more were for ST-segment-elevation myocardial infarction with cardiogenic shock (8.4% versus 4.3%). For the overall PCI cohort, after risk adjustment, there was no significant evidence of worse, or better, outcomes in lower volume centers from our own study, or in combination with results from other studies. For primary PCI, there was also no evidence for increased or decreased mortality in lower volume centers. CONCLUSIONS: After adjustment for differences in case mix and clinical presentation, this study supports the conclusion of no trend for increased mortality in lower volume centers for PCI in the UK healthcare system. CLINICAL TRIAL REGISTRATION: https://www.clinicaltrials.gov. Unique identifier: NCT02184949.

Identification of the Asymptomatic Patient With Severe Mitral Regurgitation: Discrepancy Between Research and Clinical Practice.

Organic mitral regurgitation (MR) is a common disorder, and because of the increase in population and its aging, the occurrence of MR is steadily increasing. Current guideline recommendations on the management of asymptomatic severe MR are conflicting and based solely on registries or nonrandomized trials in expert heart valve clinics, resulting in a lack of evidence for the best treatment strategy. In this review, we will evaluate the latest evidence on diagnostic approaches and treatment strategies for asymptomatic patients without a clear indication for surgical intervention. Implications for management in daily practice are discussed, including an update on the diagnostic approaches that are currently available for the evaluation of MR. For optimal care, it is important that every severe MR patient, including the unidentified patient, is referred to a specialized heart team and is assessed on an individual basis according to the guideline recommendations, experience of the surgical center, and the patient's characteristics and preferences. Screening and diagnostic approaches need to be performed on the basis of standardized protocols and strict criteria. In addition, specialized valve centers must meet the surgical criteria to guarantee high reparability rates in asymptomatic patients. Awareness among cardiologists and cardiothoracic surgeons, improved guidelines adherence, and a systematic approach, including strict criteria in the management of asymptomatic patients with severe organic MR, will ensure reliable and applicable results in research and daily clinical practice.

Multiparametric cardiovascular magnetic resonance surveillance of acute cardiac allograft rejection and characterisation of transplantation-associated myocardial injury: a pilot study.

BACKGROUND: Serial surveillance endomyocardial biopsies are performed in patients who have recently undergone heart transplantation in order to detect acute cardiac allograft rejection (ACAR) before symptoms occur, however the biopsy process is associated with a number of limitations. This study aimed to prospectively and longitudinally evaluate the performance of multiparametric cardiovascular magnetic resonance (CMR) for detecting and monitoring ACAR in the early phase post-transplant, and characterize graft recovery following transplantation. METHODS: All patients receiving a heart transplant at a single UK centre over a period of 25 months were approached within one month of transplantation. Multiparametric CMR was prospectively performed on the same day as biopsy on four separate occasions (6 weeks, 10 weeks, 15 weeks and 20 weeks post-transplant). CMR included assessment of global and regional ventricular function, myocardial tissue characterization (T1 mapping, T2 mapping, extracellular volume, LGE) and pixel-wise absolute myocardial blood flow quantification. CMR parameters were compared with biopsy findings. As is standard, grade 2R or higher ACAR was considered significant. RESULTS: 88 CMR-matched biopsies were performed in 22 patients. Eight (9%) biopsies in 5 patients demonstrated significant ACAR. Significant ACAR was associated with a reduction in circumferential strain (-12.7±2.5% vs. -13.7±3.6%, p=0.047) but there was considerable overlap between groups. Whilst trends were observed between ACAR and proposed CMR markers of oedema, particularly after adjusting for primary graft dysfunction, differences were not significant. Significant improvements were seen in markers of graft structure and contractility, oedema and microvascular function over the period studied, although few parameters normalised. CONCLUSIONS: This study provides novel insight into the myocardial injury associated with transplantation, and its recovery, however multiparametric CMR was not able to accurately detect ACAR during the early phase post-transplantation.

The mammalian Ste20-like kinase 2 (Mst2) modulates stress-induced cardiac hypertrophy.

The Hippo signaling pathway has recently moved to center stage in cardiac research because of its key role in cardiomyocyte proliferation and regeneration of the embryonic and newborn heart. However, its role in the adult heart is incompletely understood. We investigate here the role of mammalian Ste20-like kinase 2 (Mst2), one of the central regulators of this pathway. Mst2(-/-) mice showed no alteration in cardiomyocyte proliferation. However, Mst2(-/-) mice exhibited a significant reduction of hypertrophy and fibrosis in response to pressure overload. Consistently, overexpression of MST2 in neonatal rat cardiomyocytes significantly enhanced phenylephrine-induced cellular hypertrophy. Mechanistically, Mst2 positively modulated the prohypertrophic Raf1-ERK1/2 pathway. However, activation of the downstream effectors of the Hippo pathway (Yes-associated protein) was not affected by Mst2 ablation. An initial genetic study in mitral valve prolapse patients revealed an association between a polymorphism in the human MST2 gene and adverse cardiac remodeling. These results reveal a novel role of Mst2 in stress-dependent cardiac hypertrophy and remodeling in the adult mouse and likely human heart.

Voxel-wise quantification of myocardial blood flow with cardiovascular magnetic resonance: effect of variations in methodology and validation with positron emission tomography.

BACKGROUND: Quantitative assessment of myocardial blood flow (MBF) from cardiovascular magnetic resonance (CMR) perfusion images appears to offer advantages over qualitative assessment. Currently however, clinical translation is lacking, at least in part due to considerable disparity in quantification methodology. The aim of this study was to evaluate the effect of common methodological differences in CMR voxel-wise measurement of MBF, using position emission tomography (PET) as external validation. METHODS: Eighteen subjects, including 9 with significant coronary artery disease (CAD) and 9 healthy volunteers prospectively underwent perfusion CMR. Comparison was made between MBF quantified using: 1. Calculated contrast agent concentration curves (to correct for signal saturation) versus raw signal intensity curves; 2. Mid-ventricular versus basal-ventricular short-axis arterial input function (AIF) extraction; 3. Three different deconvolution approaches; Fermi function parameterization, truncated singular value decomposition (TSVD) and first-order Tikhonov regularization with b-splines. CAD patients also prospectively underwent rubidium-82 PET (median interval 7 days). RESULTS: MBF was significantly higher when calculated using signal intensity compared to contrast agent concentration curves, and when the AIF was extracted from mid- compared to basal-ventricular images. MBF did not differ significantly between Fermi and Tikhonov, or between Fermi and TVSD deconvolution methods although there was a small difference between TSVD and Tikhonov (0.06 mL/min/g). Agreement between all deconvolution methods was high. MBF derived using each CMR deconvolution method showed a significant linear relationship (p<0.001) with PET-derived MBF however each method underestimated MBF compared to PET (by 0.19 to 0.35 mL/min/g). CONCLUSIONS: Variations in more complex methodological factors such as deconvolution method have no greater effect on estimated MBF than simple factors such as AIF location and observer variability. Standardization of the quantification process will aid comparison between studies and may help CMR MBF quantification enter clinical use.

Multiparametric cardiovascular magnetic resonance assessment of cardiac allograft vasculopathy.

OBJECTIVES: This study sought to evaluate the diagnostic performance of multiparametric cardiovascular magnetic resonance (CMR) for detecting cardiac allograft vasculopathy (CAV) using contemporary invasive epicardial artery and microvascular assessment techniques as reference standards, and to compare the performance of CMR with that of angiography. BACKGROUND: CAV continues to limit the long-term survival of heart transplant recipients. Coronary angiography has a Class I recommendation for CAV surveillance and annual or biannual surveillance angiography is performed routinely in most centers. METHODS: All transplant recipients referred for surveillance angiography at a single UK center over a 2-year period were prospectively screened for study eligibility. Patients prospectively underwent coronary angiography followed by coronary intravascular ultrasound, fractional flow reserve, and index of microcirculatory resistance. Within 1 month, patients underwent multiparametric CMR, including assessment of regional and global ventricular function, absolute myocardial blood flow quantification, and myocardial tissue characterization. In addition, 10 healthy volunteers underwent CMR. RESULTS: Forty-eight patients were recruited, median 7.1 years (interquartile range: 4.6 to 10.3 years) since transplantation. The CMR myocardial perfusion reserve was the only independent predictor of both epicardial (ß = -0.57, p < 0.001) and microvascular disease (ß = -0.60, p < 0.001) on stepwise multivariable regression. The CMR myocardial perfusion reserve significantly outperformed angiography for detecting moderate CAV (area under the curve, 0.89 [95% confidence interval (CI): 0.79 to 1.00] vs. 0.59 [95% CI: 0.42 to 0.77], p = 0.01) and severe CAV (area under the curve, 0.88 [95% CI: 0.78 to 0.98] vs. 0.67 [95% CI: 0.52 to 0.82], p = 0.05). CONCLUSIONS: CAV, including epicardial and microvascular components, can be detected more accurately using noninvasive CMR-based absolute myocardial blood flow assessment than with invasive coronary angiography, the current clinical surveillance technique.

Comprehensive validation of cardiovascular magnetic resonance techniques for the assessment of myocardial extracellular volume.

BACKGROUND: Extracellular matrix expansion is a key element of ventricular remodeling and a potential therapeutic target. Cardiovascular magnetic resonance (CMR) T1-mapping techniques are increasingly used to evaluate myocardial extracellular volume (ECV); however, the most widely applied methods are without histological validation. Our aim was to perform comprehensive validation of (1) dynamic-equilibrium CMR (DynEq-CMR), where ECV is quantified using hematocrit-adjusted myocardial and blood T1 values measured before and after gadolinium bolus; and (2) isolated measurement of myocardial T1, used as an ECV surrogate. METHODS AND RESULTS: Whole-heart histological validation was performed using 96 tissue samples, analyzed for picrosirius red collagen volume fraction, obtained from each of 16 segments of the explanted hearts of 6 patients undergoing heart transplantation who had prospectively undergone CMR before transplantation (median interval between CMR and transplantation, 29 days). DynEq-CMR-derived ECV was calculated from T1 measurements made using a modified Look-Locker inversion recovery sequence before and 10 and 15 minutes post contrast. In addition, ECV was measured 2 to 20 minutes post contrast in 30 healthy volunteers. There was a strong linear relationship between DynEq-CMR-derived ECV and histological collagen volume fraction (P<0.001; within-subject: r=0.745; P<0.001; r(2)=0.555 and between-subject: r=0.945; P<0.01; r(2)=0.893; for ECV calculated using 15-minute postcontrast T1). Correlation was maintained throughout the entire heart. Isolated postcontrast T1 measurement showed significant within-subject correlation with histological collagen volume fraction (r=-0.741; P<0.001; r(2)=0.550 for 15-minute postcontrast T1), but between-subject correlations were not significant. DynEq-CMR-derived ECV varied significantly according to contrast dose, myocardial region, and sex. CONCLUSIONS: DynEq-CMR-derived ECV shows a good correlation with histological collagen volume fraction throughout the whole heart. Isolated postcontrast T1 measurement is insufficient for ECV assessment.

Non-invasive approaches for the diagnosis of acute cardiac allograft rejection.

Despite modern immunosuppressive regimes, acute rejection remains a leading cause of morbidity and mortality in heart transplant recipients. Clinical features are unreliable, and therefore, screening is performed in order to detect rejection, and hence, augment immunosuppressive therapy, at an early stage, with the aim of reducing short- and long-term sequelae. Histological analysis of right ventricular myocardial tissue obtained at endomyocardial biopsy remains the 'gold standard' surveillance technique; however 'biopsy-negative' rejection occurs in up to 20% of patients, the procedure is associated with uncommon but potentially serious complications and it is expensive. Non-invasive screening would, conceivably, be safer, more tolerable and cheaper, and could potentially allow more comprehensive monitoring. The evidence for non-invasive methods of diagnosing acute rejection, including assessment of myocardial deformation, myocardial tissue characterisation, electrophysiological monitoring, visualisation of cellular and molecular components of rejection and peripheral monitoring of immune activation, is reviewed.

Pulmonary artery pressure in cystic fibrosis adults: characteristics, clinical correlates and long-term follow-up.

BACKGROUND: We examined pulmonary artery pressure (PAP) characteristics of CF adults, studied clinical correlates and long-term survival. METHODS: Comprehensive clinical data were collected and Doppler echocardiography was used to estimate PAP in 109 stable CF adults and 50 healthy controls. RESULTS: CF patients had lower day and night-time oxygen status, elevated CRP and BNP, and elevated PAP (27.7(13.2, 62.8) mmHg patients v 17.9(11.3, 30.9) mmHg controls, p<0.001). Even patients with mild pulmonary disease had raised PAP. PAP measurements strongly correlated with arterial partial pressure of oxygen (PaO(2), r=-0.673, p<0.001), and FEV(1) percentage predicted (FEV(1)%, r=-0.642, p<0.001) which were both independent predictors of PAP. At 10 year follow up PAP measurements were related to survival but FEV(1)% and PaO(2) were both stronger predictors of death. CONCLUSIONS: PAP is raised in CF adults and correlates with pulmonary disease severity. Unlike PaO(2) and FEV(1)%, it does not appear to be an independent prognostic marker.

Comparison of real-time three-dimensional echocardiography with cardiovascular magnetic resonance for left ventricular volumetric assessment in unselected patients.

AIMS: To compare left ventricular (LV) volume indices and the ejection fraction (EF) obtained using real-time three-dimensional echocardiography (RT3DE) and cardiovascular magnetic resonance (CMR) in unselected patients representative of 'real-world' clinical practice, and to determine the effect of RT3DE image quality on these parameters. METHODS AND RESULTS: Sixty consecutive patients undergoing CMR underwent same day RT3DE. LV volume and EF measurements were made using both modalities and compared. All scans were independently analysed by a second observer to assess inter-observer variability, and 40% were re-analysed to assess intra-observer variability. RT3DE image quality was graded as good, adequate, and non-analysable. Thirteen (22%) patients had good RT3DE image quality, 29 (48%) had adequate image quality, and 18 (30%) had image quality precluding analysis. Body mass index and arrhythmia frequency were higher in patients with suboptimal image quality. RT3DE significantly underestimated end-diastolic volume (EDV) (-45 ± 35 mL, P < 0.001), end-systolic volume (ESV) (-11 ± 24 mL, P = 0.004), and EF (-7 ± 9%, P < 0.001) compared with CMR although the degree of underestimation was substantially less when image quality was good. Eleven patients (18%) classified as having a normal EF by CMR had a reduced EF according to RT3DE, all but one of which had suboptimal image quality. Observer variability for RT3DE was higher than for CMR for all parameters, however, the difference was not significant when RT3DE image quality was good. CONCLUSIONS: In contrast to previously published data from highly selected patient groups, 'real-world' RT3DE substantially underestimates LV volumes and EF. The degree of underestimation is related to image quality.