Invasive Gradient Research Articles

TCT-389 Invasive Versus Echocardiographic Gradients With Balloon-Expandable and Self-Expanding Transcatheter Aortic Valves

TCT-389 Invasive Versus Echocardiographic Gradients With Balloon-Expandable and Self-Expanding Transcatheter Aortic Valves

Invasive and Doppler Transvalvular gradients after transcatheter aortic valve replacement

Abstract Background Differences in mean gradients after Transcatheter valve replacement (TAVR) vary depending on the valve type and the modality used to measure the gradients. Currently there is a paucity of data on the relationship between invasive and doppler derived gradients after TAVR. Purpose We sort to assess the difference in doppler, and catheter derived aortic valve gradients after TAVR Methods This is a single center retrospective study using consecutive patients who presented for TAVR on account of native aortic valve stenosis at our institution from May 2012 till December 2020. Patients with both intraoperative invasive and postoperative doppler derived pressure gradients were included in the analysis. Student T-test were used to compare mean gradients. Pearson's correlation test was used to examine the correlation between measured gradients. Results A total of 587 patients were included in our study. Fifty one percent were male and 462 (78.7%) underwent TAVR with a balloon expandable valve. In the entire cohort the mean gradient measured invasively was significantly lower than those measured by echo doppler (4.48±3.25 vs. 5.57±3.11, P<0.001). There, however, was a positive correlation between invasive and doppler measured gradients (figure 1). In those who received balloon expandable valves, the invasive gradient was 4.39±3.30 and the doppler derived gradient was 5.47±3.04 (P<0.001), while in those self-expanding valves, the invasive gradient was 4.81±3.04 and doppler derived gradient was 5.94±3.36 (P<0.001). Conclusion Post TAVR gradients were all significantly lower when measured invasively as compared to those measured using doppler. Self-expanding valves overall had higher residual gradients. Further studies are needed to assess the correlations between invasively measured gradients and clinical outcomes post TAVR. Funding Acknowledgement Type of funding sources: None.

Comparison of Transvalvular Aortic Mean Gradients Obtained by Intraprocedural Echocardiography and Invasive Measurement in Balloon and Self-Expanding Transcatheter Valves.

BackgroundConcerns about discordance between echocardiographic and invasive mean gradients after transcatheter aortic valve replacement (TAVR) with balloon‐expandable valves (BEVs) versus self‐expanding valves (SEVs) exist.Methods and ResultsIn a multicenter study, direct‐invasive and echocardiography‐derived transvalvular mean gradients obtained before and after TAVR were compared as well as post‐TAVR and discharge echocardiographic mean gradients in BEVs versus SEVs in 808 patients. Pre‐TAVR, there was good correlation (R=0.614; P<0.0001) between direct‐invasive and echocardiography‐derived mean gradients and weak correlation (R=0.138; P<0.0001) post‐TAVR. Compared with post‐TAVR echocardiographic mean gradients, both valves exhibit lower invasive and higher discharge echocardiographic mean gradients. Despite similar invasive mean gradients, a small BEV exhibits higher post‐TAVR and discharge echocardiographic mean gradients than a large BEV, whereas small and large SEVs exhibit similar post‐TAVR and discharge mean gradients. An ejection fraction <50% (P=0.028) and higher Society of Thoracic Surgeons predicted risk of mortality score (P=0.007), but not invasive or echocardiographic mean gradient ≥10 mm Hg (P=0.378 and P=0.341, respectively), nor discharge echocardiographic mean gradient ≥20 mm Hg (P=0.393), were associated with increased 2‐year mortality.ConclusionsInvasively measured and echocardiography‐derived transvalvular mean gradients correlate well in aortic stenosis but weakly post‐TAVR. Post‐TAVR, echocardiography overestimates transvalvular mean gradients compared with invasive measurements, and poor correlation suggests these modalities cannot be used interchangeably. Moreover, echocardiographic mean gradients are higher on discharge than post‐TAVR in all valves. Despite similar invasive mean gradients, a small BEV exhibits higher post‐TAVR and discharge echocardiographic mean gradients than a large BEV, whereas small and large SEVs exhibit similar post‐TAVR and discharge mean gradients. Immediately post‐TAVR, elevated echocardiographic‐derived mean gradients should be assessed with caution and compared with direct‐invasive mean gradients. A low ejection fraction and higher Society of Thoracic Surgeons score, but not elevated mean gradients, are associated with increased 2‐year mortality.

A novel technique for invasive aortic valve pressure gradient measurement using a 6 Fr Swan-Ganz catheter: a case series

BackgroundSimultaneous left ventricular (LV) and aortic (Ao) pressure gradient assessment has been rendered challenging since the recall of the Langston catheter. Here we describe a simple method for simultaneous LV and Ao pressure gradient assessment using a Swan-Ganz catheter.Case summaryWe describe two cases where assessment of simultaneous left ventricle and Ao valve gradients was done using a Swan-Ganz catheter to assess the degree of Ao stenosis and dynamic LV outflow obstruction.DiscussionUsing Swan-Ganz catheter assessment of simultaneous left ventricle and Ao valve gradients can simplify the procedure with reduced cost and increased patient safety.

Endovascular treatment for native coarctation in children in France. A multicentric, retrospective long-term analysis

Percutaneous treatment of native coarctation (coA), gold standard in adult patients, is still debated in children. We aim to report the French multicentre experience. All patients aged 1 to 18 yrs with native coA, treated percutaneously between 01/2000 and 12/2018, were included in this multcentric (9 centres) retrospective survey. One hundred and thirty three children (34 female) were included. Indication for treatment was hypertension in 109, exercise hypertension in 8 and other reasons in 16 patients. Mean age at intervention was 11.5 ± 3.9 years, mean weight 41 ± 18 kg. Procedure consisted of isolated balloon dilatation in 5 (mean age 2,63 yrs, mean weight 12 kg), balloon dilatation followed by stent implantation in 8 (mean age 11 yrs, mean weight 37 kg), and immediate stent implantation in 120 (mean age 12 yrs, mean weight 43 kg). Stents used ( n = 124/128) were covered in 43, non-covered in 77, including 38 open cell stents. Invasive gradient across coA dropped from 28 mmHg (range 5 to 64) at baseline ( n = 124) to 3 mmHg (range -5 to 20) after intervention ( n = 105). Three associated lesions were treated: 1 PDA closure, 1 aortic valvuloplasty and 1 left SVC occlusion. Serious vascular complications occurred in 8 patients (6%) (3 pseudo-aneurysms, 2 dissections, 2 stenosis and 1 occlusion) requiring surgery in 2. Reintervention was performed in 22%: 2 patients had surgery, 28 were treated percutaneously (14 balloon dilatations, 14 stent implantations). Mean follow-up reached 4.9 ± 4.7 years. At latest follow-up, 25% remained hypertensive with 15 patients (11%) on anti-hypertensive medication. MRI, CTscan or fluoroscopy imaging, are available in 52 patients during follow-up (39%). Rate of aneurysm formation, stent fracture and risks factors for reintervention or residual hypertension will be presented. Percutaneous treatment of native coarctation was safe and efficient in our french population. Close follow-up is required for longer-term results.

Invasive versus echocardiographic gradients in degenerated surgical aortic valve prostheses: A multicenter study

ObjectivesTo compare echocardiographic and invasive mean gradients obtained concomitantly in degenerated bioprosthetic surgical aortic valves (SAVRs). MethodsIn a multicenter study, we compared concomitant echocardiographic and invasive mean gradients of SAVR, obtained before valve-in-valve transcatheter aortic valve replacement in all patients, patients with primary stenosis (AS), primary aortic regurgitation (AR), and mixed aortic valve disease (MAVD), and in small versus large valves (≤ or >23 mm). Dimensionless index (DI) was calculated in all groups. ResultsIn total, 74 patients were included and data presented as median (interquartile range). Echocardiography-catheterization mean gradient discordance was observed in all patients (invasive = 22 mm Hg [11-34] vs echocardiographic = 32 mm Hg [21-42], P = .013), small valves (invasive = 15 mm Hg [8-34] vs echocardiographic = 28 mm Hg [21-41], P = .013), and large valves (invasive = 20 mm Hg [8.5-27.13] vs echocardiographic = 32 mm Hg [25.5 ̶ 41.5], P < .0001), with a bias of 8 ± 15 mm Hg and wide limits of agreement (–22 to 39 mm Hg) on Bland–Altman plots, indicating these modalities may not be interchangeable. Discordance occurred in AR (invasive = 3 mm Hg [1-6] vs echocardiographic = 12 mm Hg [7-22], P = .017) and in MAVD (invasive = 19 mm Hg [12-29] vs echocardiographic = 31 mm Hg [23-39], P < .0001) but not in AS (invasive = 35 mm Hg [24-45] vs echocardiographic = 41 mm Hg [30-50], P = .45). A lower DI (0.21 [0.14-0.25]) occurred in AS compared with MAVD (0.31 [0.19-0.39]) and AR (0.55 [0.51-0.69]), P < .0001. ConclusionsDiscordance between echocardiography and invasive mean gradients exists in degenerated SAVR, regardless of valve size, but depends on mechanism of failure and DI helps stratify these patients. With a discrepancy between echocardiographic mean gradients AND the patient's symptoms OR the valve leaflet structure and/or mobility on imaging, especially before redo-SAVR or valve-in-valve transcatheter aortic valve replacement, invasive gradients may adjudicate the true valvular hemodynamics.

Baseline intracardiac echocardiography predicts haemodynamic changes and Doppler velocity patterns during follow-up after percutaneous pulmonary valve implantation.

Intracardiac echocardiography Doppler-derived gradients have previously been shown to correlate with post-procedure echocardiographic evaluations when compared with invasive gradients measured during percutaneous pulmonary valve implantation, suggesting that intracardiac echocardiography could offer an accurate and predictable starting point to estimate valve function after percutaneous pulmonary valve implantation. We performed a retrospective chart review of 51 patients who underwent percutaneous pulmonary valve implantation between September 2018 and December 2019 in whom intracardiac echocardiography was performed immediately after valve implantation. We evaluated the correlation between intracardiac echocardiography gradients and post-procedural Doppler-derived gradients. Among the parameters assessed, those which demonstrated the strongest correlation were used to create a predictive model of expected echo-derived gradients after percutaneous pulmonary valve implantation. The equation was validated on the same sample data along with a subsequent cohort of 25 consecutive patients collected between January 2020 and July 2020. All the assessed correlation models between intracardiac echocardiography evaluation and post-procedure transthoracic echocardiographic assessments were statistically significant, presenting moderate to strong correlations. The strongest relationship was found between intracardiac echocardiography mean gradients and post-procedural transthoracic echocardiographic mean gradients. Therefore, an equation was created based on the intracardiac echocardiography-derived mean gradient, to allow prediction of the post-procedural and follow-up transthoracic echocardiographic-derived mean gradients within a range of ±5mmHg from the observed value in more than 80% of cases. There is a strong correlation between intracardiac echocardiography and post-procedure transthoracic echocardiographic. This allowed us to derive a predictive equation that defines the expected transthoracic echocardiographic Doppler-derived gradient following the procedure and at out-patient follow-up after percutaneous pulmonary valve implantation.

A Double-Envelope Mitral Inflow Spectral Doppler Profile After MitraClip

A Double-Envelope Mitral Inflow Spectral Doppler Profile After MitraClip

Double-chambered right ventricle in adults: Invasive and noninvasive hemodynamic considerations

BackgroundData on the features of double-chambered right ventricular (DCRV) in adults are limited. It is also unclear how invasive and Doppler-derived assessments of right ventricular (RV) obstruction in DCRV correlate. MethodsRetrospective review of 17 adults (age ≥18 years) diagnosed with DCRV who underwent right heart catheterization at Mayo Clinic, MN between 1990 and 2021. Clinical, echocardiographic, and invasive hemodynamics were abstracted from the medical charts. ResultsMean age was 44 ± 19 years and 7 (41%) patients were female. Two patients (12%) had undergone prior surgical repair of DCRV with ventricular septal defect (VSD) closure and had residual/recurrent obstruction; a VSD had been previously documented in 16 patients (94%). RV inflow to pulmonary artery systolic gradient at catheterization was 42 (19; 95) mmHg. The correlation coefficient between RV inflow to pulmonary artery systolic gradients and Doppler-derived peak gradients was 0.87 (p < 0.0001); the coefficient between the RV inflow to pulmonary artery systolic gradients and Doppler-derived systolic mean gradients was 0.85. Doppler-derived maximum instantaneous gradients were significantly higher than directly measured values (p = 0.002) while no difference was seen when invasive gradients were compared to Doppler-derived systolic mean gradients (p = 0.16). There was no association between New York Heart Association functional class III/IV, presence of dyspnea or syncope/pre-syncope and invasively measured RV gradients. ConclusionSignificant discrepancy between non-simultaneous echo-derived and invasively measured intracavitary RV gradients was seen in adults with DCRV. There was no correlation between the degree of RV obstruction and symptoms/functional capacity.

Sequential dilation strategy in stent therapy of the aortic coarctation: A single centre experience

BackgroundIn our study, we sought to analyse the mid-term results after interventional aortic coarctation (CoA) stenting with sequential dilation of the stent. MethodsThe data of all 218 patients, who are above the age of 6 years and underwent CoA-stent implantation in our hospital, were retrospectively analysed on the rate of re-interventions, complications and arterial hypertension at a follow-up time of 31 months. To avoid any aortic complications, stents were deployed primarily not in full size and a second cardiac catheterisation for further dilatation was scheduled within 6–12 months after the stent implantation. ResultsThe median peak invasive systolic pressure gradient declined significantly from 26.2 mmHg to 2.7 mmHg after stenting. There was one procedure related death due to an aortic rupture after stent implantation. There were in total 33 (15.1%) procedure-related complications including femoral artery complications, stent fracture and stent dislocation (in 9, 9 and 7 patients, respectively). In 85 patients a re-dilatation and in 25 patients a second stent-implantation was necessary at the first re-intervention. The systolic blood pressure declined significantly from 144 mmHg to 131 mmHg after stenting. The number of patients being normotensive changed from 18% before stenting to 78.5% after stenting with adjusted antihypertensive medication. ConclusionAortic stenting is an effective means for CoA treatment. With sequential dilation of the stent, a very low rate of life-threatening procedural complications and mortality can be achieved. CoA stenting with proper antihypertensive medications results in better control of blood pressure.

Liver Stiffness-Based Model Predicts Hepatic Venous Pressure Gradient in Patients Undergoing Hepatectomy and Liver Transplantation

Background: Invasive hepatic venous pressure gradient (HVPG) measurement is the gold standard test to assess portal hypertension. The aim was to develop a model predictive of clinically significant portal hypertension (HVPG≥10mmHg) using pre-operative noninvasive makers. Methods: 161 patients [66% men, median age of 63 years] who have been planned for liver resection/transplantation were enrolled prospectively and preoperative liver stiffness measurement (LSM), liver function test, and intraoperative HVPG were performed. Results: Median LSM, and HVPG were 9.5kPa, and 5mmHg respectively. No underlying liver disease (F0/1), chronic liver disease (F2/3), and cirrhosis (F4) were found in 32.9%, 32.9% and 34.2% patients respectively. The study cohort was randomly divided into training [n=106] and validation [n=55] sets. Independent predictors of HVPG≥10mmHg in the training set, LSM [p< 0.01, OR=1.1], total bilirubin [p=0.04, OR=0.9], alkaline phosphatase [p=0.02, OR=1], and international normalized ratio [p< 0.01, OR=41.4], were used to develop a probability score model called HVPG10score. Area under receiver operating curve in the training and internal validation sets were 0.91 [95%CI:0.83-0.98] and 0.93 [95%CI:0.86-0.99] respectively with a cutoff of 0.15. HVPG10score was calculated by multiplying the probability by 100. In the overall cohort, HVPG10score of 15 would predict the individual risk of HVPG≥10mmHg with 83% accuracy, 90% sensitivity, 81% specificity and 96% negative predictive value. Conclusions: HVPG10score is an easy-to-use noninvasive continuous scale tool to predict HVPG≥10mmHg. A score < 15 would accurately rule out the need for esophageal varices screening and risk of decompensation in >95% chronic liver disease patients.

Shunt-Induced Hepatic Encephalopathy in TIPS: Current Approaches and Clinical Challenges.

Transjugular intrahepatic portosystemic shunt (TIPS) is an established treatment tool in decompensated liver cirrhosis that has been shown to prolong transplant-free survival. Hepatic encephalopathy (HE) is a frequent complication of decompensated cirrhosis, eventually induced and/or aggravated by TIPS, that remains a clinical challenge especially in these patients. Therefore, patient selection for TIPS requires careful assessment of risk factors for HE. TIPS procedural parameters regarding stent size and invasive portosystemic pressure gradient measurements thereby have an important role. Endovascular shunt modification, in combination with a conservative medical approach, often results in a significant reduction of symptoms. This review summarizes HE molecular mechanisms and pathophysiology as well as diagnostic and therapeutic approaches targeting shunt-induced HE.

Abstract 17451: Use of Intracardiac Echocardiography to Predict Follow-Up Hemodynamic Changes After Transcatheter Pulmonary Valve Implantation

Objective: Evaluate the correlation between intracardiac echocardiography (ICE) gradients and next-day and one-month transthoracic echocardiography (TTE) gradients, after percutaneous pulmonary valve implantation (PPVI) Background: Post-procedure Doppler-derived gradients have gained popularity as acceptable parameters to evaluate valve function after PPVI, but they have no proven correlation with the invasive gradient measured during the procedure, indeed a large disparity between these two measurements has been described. Interestingly, ICE gradients, which are also an invasive assessment, have been suggested to present a strong correlation with post-procedure echocardiographic evaluations, and their application could allow a more accurate and predictable evaluation of valve function, establishing a typical pattern of short-term hemodynamic progression in these patients. Methods: We performed a retrospective chart review of 84 patients who underwent PPVI between January 2018 and December 2019 and selected 51 patients in whom ICE was performed after valve implantation. We evaluated the correlation between ICE and RV-PA gradients with post-procedural Doppler-derived gradients. Among the parameters assessed, the one which demonstrated the strongest correlation was used to create a predictive model to estimate the expected gradients after PPVI. Results: All the assessed correlation models between Doppler-derived parameters during ICE evaluation and post-procedure TTE evaluations were statistically significant, and presented moderate to strong linear relationships. The strongest correlation was found between ICE Doppler mean gradient and post-procedural Doppler mean gradient. The derived predictive equation was distributed by the size of the device implanted and body mass index. We found this model was capable of predicting post-procedural evaluations (mean Doppler-derived gradients at 1 day and 1 month) within a range of ±5 mmHg from the observed value in more than 80% of cases. Conclusions: There is a strong correlation between ICE and post-procedure TTE. This allowed us to derive a predictive equation, distributed by body size and device size that defines expected echo Doppler-derived hemodynamic pathways after PPVI.

Balloon Angioplasty for Native Aortic Coarctation in 3- to 12-Month-Old Infants.

Balloon angioplasty for native coarctation of the aorta (CoA) is successful in children and adults but in neonates results in frequent restenosis. The efficacy of balloon angioplasty for native CoA during infancy beyond the neonatal period was examined in infants aged 3 to 12 months of age. A retrospective review of 68 infants who underwent balloon angioplasty for native CoA. 95% CI are in parentheses. Procedural age was (mean±SD) 6±3.4 months and weight was 7±1.8 kg. Balloon angioplasty produced a large decrease in both the noninvasive arm-to-leg blood pressure gradient (41.2±18.7 to 5.6±9.6 mm Hg) and the invasive peak systolic pressure gradient (34±12 to 11±9 mm Hg). Balloon angioplasty increased the CoA diameter from 2.7±1 mm to 4.6±1.2 mm. One patient was lost to follow-up. A catheter reintervention was required in 11.8% and surgery in 10.3%. The hazard of reintervention was highest early. Median freedom from reintervention was 89% (95% CI, 80%-96%) at 1 year, 83% (95% CI, 73%-92%) at 5 years, and 81% (95% CI, 69%-90%) at 10 years. Femoral artery thrombosis was documented in 6 (9%) infants without any long-term consequence. One patient developed a small aortic aneurysm late and has not required treatment. A robust estimate of the frequency of aortic aneurysms remains to be determined as the majority of subjects have not had cross-sectional imaging. Balloon angioplasty of native CoA is effective and safe in infants aged 3 to 12 months with outcomes comparable to those in older children and adults. Catheter reinterventions can avoid the need for surgery in most patients.

Covered stent placement for treatment of coarctation of the aorta: immediate and long-term results

Objectives This study aimed to describe the safety and efficacy of covered stents in patients with coarctation of aorta (CoA) for immediate and long-term follow-up. Background Covered stents are increasingly being used in (re)CoA, mainly to reduce the risk of aortic wall injuries (AWI). However, limited data are available on intermediate and long-term outcome. Methods In 89 patients (67.4% male) with a mean age of 23.9 ± 15.8 (min max range 5.1–71.6) years were 102 covered stents implanted (January 2003 – December 2017). Short-term pre/post-implant hemodynamics and angiographic data were reported. Changes in blood pressure, the use of antihypertensive drugs and complications were recorded during follow-up. Results The procedural success rate was 100%. The mean invasive ascending-to-descending aorta systolic gradient under general anaesthesia decreased from 25 ± 16 mmHg to 4 ± 7 mmHg (p < 0.001). After a mean follow-up time of 6.6 ± 3.7 years, there was a persistent improvement of the mean systolic blood pressure gradient between right arm and leg (−7 ± 18 vs 38 ± 24 mmHg; p < 0.001). A larger proportion of patients required antihypertensive medication (33.7% vs 50.0%, p = 0.017) and needed ≥ 2 drugs (20.2% vs 27.4%, p = 0.066) to control blood pressure. Long-term adverse events were found in 4.5% of patients [covered stent fracture (n = 3), aneurysm formation (n = 2)]. Conclusions Covered stent implantation for CoA is highly successful, safe and results in a persistent hemodynamic improvement in the immediate and long-term outcome. Lifelong follow-up with additional antihypertensive drug treatment is mandatory to maintain favourable hemodynamic results after stenting. CONDENSED ABSTRACT Long-term follow-up data on covered stents in patients with coarctation of the aorta are scarce. A cohort of 89 patients was reviewed. The procedural implantation success rate was 100%. The invasive gradient decreased from 25 ± 16 mmHg to 4 ± 7 mmHg (p < 0.001). After follow-up of 6.6 ± 3.7 years, there was a persistent improvement of the clinical systolic blood pressure gradient (−7 ± 18 vs 38 ± 24 mmHg; p < 0.001). However, a larger proportion of patients required antihypertensive medication (33.7% vs 50.0%, p = 0.017). Covered stent implantation results in favourable hemodynamic effects, but lifelong follow-up with additional antihypertensive drug treatment is mandatory to maintain these results.

Presence of mitral stenosis is a risk factor of new development of acute decompensated heart failure early after transcatheter aortic valve implantation

AimsAcute decompensated heart failure (ADHF) can occur early after transcatheter aortic valve implantation (TAVI), but the risk factors or mechanisms associated with it have not been fully determined. This hypothesis-generating...

TCT CONNECT-103 Immediate Post-TAVR Echocardiographic and Invasive Mean Gradients in Balloon Versus Self-Expanding Valves: A Multicenter Retrospective Study

TCT CONNECT-103 Immediate Post-TAVR Echocardiographic and Invasive Mean Gradients in Balloon Versus Self-Expanding Valves: A Multicenter Retrospective Study

Noninvasive imaging assessment of portal hypertension.

Portal hypertension (PH) is a spectrum of complications of chronic liver disease (CLD) and cirrhosis, with manifestations including ascites, gastroesophageal varices, splenomegaly, hypersplenism, hepatic hydrothorax, hepatorenal syndrome, hepatopulmonary syndrome and portopulmonary hypertension. PH can vary in severity and is diagnosed via invasive hepatic venous pressure gradient measurement (HVPG), which is considered the reference standard. Accurate diagnosis of PH and assessment of severity are highly relevant as patients with clinically significant portal hypertension (CSPH) are at higher risk for developing acute variceal bleeding and mortality. In this review, we discuss current and upcoming noninvasive imaging methods for diagnosis and assessment of severity of PH.

Validation of four-dimensional flow cardiovascular magnetic resonance for aortic stenosis assessment

The management of patients with aortic stenosis (AS) crucially depends on accurate diagnosis. The main aim of this study were to validate the four-dimensional flow (4D flow) cardiovascular magnetic resonance (CMR) methods for AS assessment. Eighteen patients with clinically severe AS were recruited. All patients had pre-valve intervention 6MWT, echocardiography and CMR with 4D flow. Of these, ten patients had a surgical valve replacement, and eight patients had successful transcatheter aortic valve implantation (TAVI). TAVI patients had invasive pressure gradient assessments. A repeat assessment was performed at 3–4 months to assess the remodelling response. The peak pressure gradient by 4D flow was comparable to an invasive pressure gradient (54 ± 26 mmHG vs 50 ± 34 mmHg, P = 0.67). However, Doppler yielded significantly higher pressure gradient compared to invasive assessment (61 ± 32 mmHG vs 50 ± 34 mmHg, P = 0.0002). 6MWT was associated with 4D flow CMR derived pressure gradient (r = −0.45, P = 0.01) and EOA (r = 0.54, P < 0.01) but only with Doppler EOA (r = 0.45, P = 0.01). Left ventricular mass regression was better associated with 4D flow derived pressure gradient change (r = 0.64, P = 0.04). 4D flow CMR offers an alternative method for non-invasive assessment of AS. In addition, 4D flow derived valve metrics have a superior association to prognostically relevant 6MWT and LV mass regression than echocardiography.

Spartina alterniflora invasion impacts denitrifying community diversity and functioning in marsh soils

This study aimed to investigate soil denitrifying bacterial and fungal community structures and potential denitrification rates in the coastal marsh soils of Eastern China across Spartina alterniflora invasive gradients (i.e. native (Nat), native-Spartina coexisted (Ecot) and Spartina-dominated (Mono) vegetations, respectively). Plant biomass and soil chemical properties were also analyzed to understand the patterns of spatial variability of structure and function of denitrifier communities across the studied gradients. Results indicated that total, bacterial and fungal potential denitrification rates (TDR, BDR and FDR) were 5.5, 3.5 and 1.5 times greater respectively in the Mono soil than in the Nat soil. Denitrifying bacterial richness, evenness and α-diversity were 2.0, 1.3 and 1.3 times greater in the Mono soil than those in the Nat soil, while only the richness among denitrifying fungal community parameters was 1.4 times greater in the Mono soil than that in the Nat soil. Plant biomass, soil organic carbon and pH were the most important factors influencing denitrifying bacterial and fungal community structures and functions. Denitrifying bacterial community composition was related closely to BDR and TDR, while denitrifying fungal community composition was not related to FDR and TDR, thus showing that the denitrifying bacterial community is a better predictor of denitrification function following Spartina invasion.