Hemodynamic progression and outcome of asymptomatic aortic stenosis in primary care

Prediction of the Individual Aortic Stenosis Progression Rate and its Association With Clinical Outcomes

Background

The progression rate of aortic stenosis differs between patients, complicating clinical follow-up and management.

Objectives

This study aimed to identify predictors associated with the progression rate of aortic stenosis.

Methods

In this retrospective longitudinal single-center cohort study, all patients with moderate aortic stenosis who presented between December 2011 and December 2022 and had echocardiograms available were included. The individual aortic stenosis progression rate was calculated based on aortic valve area (AVA) from at least 2 echocardiograms performed at least 6 months apart. Baseline factors associated with the progression rate of AVA were determined using linear mixed-effects models, and the association of progression rate with clinical outcomes was evaluated using Cox regression.

Results

The study included 540 patients (median age 69 years and 38% female) with 2,937 echocardiograms (median 5 per patient). Patients had a linear progression with a median AVA decrease of 0.09 cm2/y and a median peak jet velocity increase of 0.17 m/s/y. Rapid progression was independently associated with all-cause mortality (HR: 1.77, 95% CI: 1.26-2.48) and aortic valve replacement (HR: 3.44, 95% CI: 2.55-4.64). Older age, greater left ventricular mass index, atrial fibrillation, and chronic kidney disease were associated with a faster decline of AVA.

Conclusions

AVA decreases linearly in individual patients, and faster progression is independently associated with higher mortality. Routine clinical and echocardiographic variables accurately predict the individual progression rate and may aid clinicians in determining the optimal follow-up interval for patients with aortic stenosis.

Improving accuracy in diagnosing aortic stenosis severity: An in-depth analysis of echocardiographic measurement error through literature review and simulation study

AIMS

The present guidelines advise replacing the aortic valve for individuals with severe aortic stenosis (AS) based on various echocardiographic parameters. Accurate measurements are essential to avoid misclassification and unnecessary interventions. The objective of this study was to evaluate the influence of measurement error on the echocardiographic evaluation of the severity of AS.

METHODS AND RESULTS

A systematic review was performed to examine whether measurement errors are reported in studies focusing on the prognostic value of peak aortic jet velocity (Vmax ), mean pressure gradient (MPG), and effective orifice area (EOA) in asymptomatic patients with AS. Out of the 37 studies reviewed, 17 (46%) acknowledged the existence of measurement errors, but none of them utilized methods to address them. Secondly, the magnitude of potential errors was collected from available literature for use in clinical simulations. Interobserver variability ranged between 0.9% and 8.3% for Vmax and MPG but was higher for EOA (range 7.7%-12.7%), indicating lower reliability. Assuming a circular left ventricular outflow tract area led to a median underestimation of EOA by 23% compared to planimetry by other modalities. A clinical simulation resulted in the reclassification of 42% of patients, shifting them from a diagnosis of severe AS to moderate AS.

CONCLUSIONS

Measurement errors are underreported in studies on echocardiographic assessment of AS severity. These errors can lead to misclassification and misdiagnosis. Clinicians and scientists should be aware of the implications for accurate clinical decision-making and assuring research validity.

Asymptomatic Aortic Stenosis in an Older Patient: How the Geriatric Approach Can Make a Difference

We present a case report of an older patient with aortic stenosis who was managed before and after transcatheter aortic valve implantation by a team of cardiologists but without the support of a geriatrician. We first describe the patient's post-interventional complications from a geriatric perspective and afterwards, discuss the unique approach that the geriatrician would have provided. This case report was written by a group of geriatricians working in an acute hospital, along with a clinical cardiologist who is an expert in aortic stenosis. We discuss the implications for modifying conventional practice in tandem with existing literature.

Factors Affecting Rate of Progression of Aortic Stenosis and Its Impact on Outcomes

The rate of aortic stenosis (AS) progression in patients with moderate AS is unclear. This study examined the risk factors of progression from moderate to severe AS and its impact on clinical outcomes. A total of 954 patients with moderate AS (valve area >1.0 and ≤1.5 cm²) and follow-up echocardiograms were included. AS progressed to severe (valve area <1.0 cm¹) in 589 patients (61.7%) over a median follow-up of 2.46 (interquartile range [IQR] 1.29 to 3.91) years. Of those who progressed to severe AS, patients were subdivided into Slow (n = 294, over 3.91 [IQR 3.11 to 5.10] years) versus Fast (n = 295, over 1.29 [IQR 0.85 to 1.85] years) Progressors, according to the median time between the 2 echocardiograms. The correlates of fast AS progression and its impact on cumulative survival and freedom from valve intervention were evaluated. On multivariate analysis, age, thickened left ventricle posterior wall, severe renal impairment, and aortic valve area were significantly associated with fast AS progression. Over a median follow-up of 6.34 (IQR 4.05 to 9.55) years, 228 patients (38.7%) died. Despite similar aortic valve intervention rates, Fast Progressors had worse 5-year survival (61.2% vs 81.9%, log-rank p <0.001) and event-free (valve intervention and all-cause mortality) survival rates (16.2% vs 55.9%, log-rank p <0.001). On multivariable Cox analysis, shorter progression to severe AS (in years) was independently associated with increased risk of all-cause mortality (hazard ratio 1.26, 95% confidence interval 1.16 to 1.37, p <0.001), or combined aortic valve intervention and death (hazard ratio 1.46, 95% confidence interval 1.38 to 1.55, p <0.001). In conclusion, fast progression from moderate to severe AS is associated with worse outcomes.

Current and new imaging techniques in risk stratification of asymptomatic severe aortic stenosis

Aortic stenosis (AS) is one of the most common valvular diseases in clinical practice. The prevalence of calcified AS with moderate or severe stenosis exceeds 2% after 75 years. The optimal timing of intervention for asymptomatic severe AS is uncertain and controversial. Identification of high-risk patients is based on echocardiographic parameters (left ventricular dysfunction, AS severity and progression), hemodynamic response to exercise, pulmonary hypertension, and elevated brain natriuretic peptides. However, early surgical aortic valve replacement (AVR), when compared to the watchful waiting approach, was associated with survival advantage. Moreover, new insights into pathophysiology of AS and advances in imaging modalities were helpful in the management of asymptomatic AS. In this report, we detail the potential role of echocardiography to guide timing of surgery and we discussed the use of early risk features based on recent imaging modalities.

Relation of Monocyte Number to Progression of Aortic Stenosis

Rapid progression of aortic stenosis (AS) is associated with poor prognosis. However, the relation between monocyte number and AS progression is unknown. Here, we detected the relation between monocyte number and AS progression. We retrospectively analyzed 220 patients with AS with at least 2 echocardiograms with the maximal interval ≥180 days from January 2016 to June 2021. AS severity was categorized by aortic jet velocity (V_max) and mean pressure gradient. Rapid progression of AS was defined when V_max increased ≥0.3 m/s/year. Patients were divided into low and high monocyte groups according to the cut-off value of the receiver-operating characteristic curve. AS progression was compared between the 2 groups. Various models of binary logistic regression were used to reveal the association between monocyte number and rapid progression. During a median of 601 days of echocardiographic follow-up (interquartile range 353 to 909), 52.7% of the population was in rapid progression. Patients in the high monocyte group had more rapid progression in both V_max and mean pressure gradient (p = 0.020 and p = 0.030, respectively). The percentage of patients with severe AS was increased by 5.4% in the low monocyte group and 16.9% in the high monocyte group. Different models of binary logistic regression showed that the monocyte number was positively associated with the rapid progression. In conclusion, a higher monocyte number was associated with the rapid progression of AS.

Diabetes Is Associated With Rapid Progression of Aortic Stenosis: A Single-Center Retrospective Cohort Study

Background

Mounting evidence indicates that rapid progression of aortic stenosis (AS) is significantly associated with poor prognosis. Whether diabetes accelerates the progression of AS remains controversial.

Objectives

The purpose of the present study was to investigate whether diabetes was associated with rapid progression of AS.

Methods

We retrospectively analyzed 276 AS patients who underwent transthoracic echocardiography at least twice with a maximum interval ≥ 180 days from January 2016 to June 2021. AS severity was defined by specific threshold values for peak aortic jet velocity (V_max) and/or mean pressure gradient. An increase of V_max ≥ 0.3 m/s/year was defined as rapid progression. The binary Logistic regression models were used to determine the association between diabetes and rapid progression of AS.

Results

At a median echocardiographic follow-up interval of 614 days, the annual increase of V_max was 0.16 (0.00–0.41) m/s. Compared with those without rapid progression, patients with rapid progression were older and more likely to have diabetes (P = 0.040 and P = 0.010, respectively). In the univariate binary Logistic regression analysis, diabetes was associated with rapid progression of AS (OR = 2.02, P = 0.011). This association remained significant in the multivariate analysis based on model 2 and model 3 (OR = 1.93, P = 0.018; OR = 1.93, P = 0.022). After propensity score-matching according to V_max, diabetes was also associated rapid progression of AS (OR = 2.57, P = 0.045).

Conclusions

Diabetes was strongly and independently associated with rapid progression of AS.

A novel approach to determine aortic valve area with phase-contrast cardiovascular magnetic resonance

BACKGROUND

Transthoracic echocardiography (TTE) is the diagnostic routine standard for assessing aortic stenosis (AS). However, its inaccuracies in determining stroke volume (SV) and aortic valve area (AVA) call for a more precise and dependable method. Phase-contrast cardiovascular magnetic resonance imaging (PC-CMR) is a promising tool to push these boundaries. Thus, the aim of this study was to validate a novel approach based on PC-CMR against the gold-standard of invasive determination of AVA in AS compared to TTE.

METHODS

A total of 50 patients with moderate or severe AS underwent TTE, cardiac catheterization and CMR. AVA via PC-CMR was determined by plotting momentary flow across the valve against flow-velocity. SV by CMR was measured directly via PC-CMR and volumetrically using cine-images. Invasive SV and AVA were determined via Fick-principle and Gorlin-formula, respectively. TTE yielded SV and AVA using continuity equation. Gradients were calculated via the modified Bernoulli-equation.

RESULTS

SV by PC-CMR (85 ± 31 ml) correlated strongly (r: 0.73, p < 0.001) with cine-CMR (85 ± 19 ml) without significant bias (lower and upper limits of agreement (LLoA and ULoA): - 41 ml and 44 ml, p = 0.83). In PC-CMR, mean pressure gradient correlated significantly with invasive determination (r: 0.36, p = 0.011). Mean AVA, as determined by PC-CMR during systole (0.78 ± 0.25 cm2), correlated moderately (r: 0.54, p < 0.001) with invasive AVA (0.70 ± 0.23 cm2), resulting in a small bias of 0.08 cm2 (LLoA and ULoA: - 0.36 cm2 and 0.55 cm2, p = 0.017). Inter-methodically, AVA by TTE (0.81 ± 0.23 cm2) compared to invasive determination showed similar correlations (r: 0.58, p < 0.001 with a bias of 0.11 cm2, LLoA and ULoA: - 0.30 and 0.52, p < 0.001) to PC-CMR. Intra- and interobserver reproducibility were excellent for AVA (intraclass-correlation-coefficients of 0.939 and 0.827, respectively).

CONCLUSIONS

Our novel approach using continuous determination of flow-volumes and velocities with PC-CMR enables simple AVA measurement with no bias to invasive assessment. This approach highlights non-invasive AS grading through CMR, especially when TTE findings are inconclusive.

Valvulo-Arterial Impedance and Dimensionless Index for Risk Stratifying Patients With Severe Aortic Stenosis

The hemodynamic effects of aortic stenosis (AS) consist of increased left ventricular (LV) afterload, reduced myocardial compliance, and increased myocardial workload. The LV in AS patients faces a double load: valvular and arterial loads. As such, the presence of symptoms and occurrence of adverse events in AS should better correlate with calculating the global burden faced by the LV in addition to the transvalvular gradient and aortic valve area (AVA). The valvulo-arterial impedance (Zva) is a useful parameter providing an estimate of the global LV hemodynamic load that results from the summation of the valvular and vascular loads. In addition to calculating the global LV afterload, it is paramount to estimate the stenosis severity accurately. In clinical practice, the management of low-flow low-gradient (LF-LG) severe AS with preserved LV ejection fraction requires careful confirmation of stenosis severity. In addition to the Zva, the dimensionless index (DI) is a very useful parameter to express the size of the effective valvular area as a proportion of the cross-section area of the left ventricular outlet tract velocity-time integral (LVOT-VTI) to that of the aortic valve jet (dimensionless velocity ratio). The DI is calculated by a ratio of the sub-valvular velocity obtained by pulsed-wave Doppler (LVOT-VTI) divided by the maximum velocity obtained by continuous-wave Doppler across the aortic valve (AV-VTI). In contrast to AVA measurement, the DI does not require the calculation of LVOT cross-sectional area, a major cause of erroneous assessment and underestimation of AVA. Hence, among patients with LG severe AS and preserved LV ejection fraction, calculation of DI in routine echocardiographic practice may be useful to identify a subgroup of patients at higher risk of mortality who may derive benefit from aortic valve replacement. This article aims to elucidate the Zva and DI in different clinical situations, correlate with the standard indexes of AS severity, LV geometry, and function, and thus prove to improve risk stratification and clinical decision making in patients with severe AS.

Relevance of Functional Mitral Regurgitation in Aortic Valve Stenosis

The clinical relevance of functional-mitral-regurgitation (FMR) in patients with aortic valve stenosis (AS) has been poorly studied using a quantitative approach. In addition, FMR prognostic value has mostly been analyzed after aortic valve replacement. Between 2010 and 2014 the echocardiograms of consecutive AS patients were retrospectively reviewed. Inclusion criteria were calcified aortic valve with transaortic-velocity >2.5 m/s and calculated mitral effective regurgitant orifice area (ERO) in the presence of mitral regurgitation. Organic mitral valve disease was an exclusion-criteria. Primary endpoint was heart failure or death under medical management. Secondary endpoint was heart failure or death. Eligible patients were 189, age 79 ± 8 years, 61% NYHA I/II, indexed aortic valve area (AVA) 0.55 ± 0.17 cm²/m². Mitral ERO was 7.6 ± 4.2 mm² (>10 mm² in 30% of patients). Longitudinal function (by S'-TDI) was associated with mitral ERO independently of ejection fraction and ventricular volumes (p = 0.01). Mitral ERO greater than 10 mm² (threshold identified by spline survival-modeling) was associated with severe symptoms (Odds ratio [OR] 3.1 [1.6 to 6.0]; p = 0.0006) and higher pulmonary-arterial-pressure (OR 3.0 [1.4 to 5.9]; p = 0.002). Follow-up was completed for 175 patients. After 4.7 [1.4 to 7.2] years, 87 (50%) patients underwent AVR, 66 (38%) had heart-failure, 64 (37%) died. No procedure on FMR was required. Mitral ERO was independently associated with primary and secondary endpoints both as continuous variable (Hazard ratio [HR] 1.15 [1.00 to 1.30]; p = 0.04 and HR 1.23 [1.05 to 1.43]; p = 0.01 per 5 mm² ERO increase) or as ERO> versus ≤10 mm². Adjustment for S'-TDI or subgroup-analysis did not affect results. The analysis by AVA revealed the incremental prognostic role of mitral ERO over AS severity. In conclusion, AS patients with concomitant FMR >10 mm² holds a higher risk during medical follow-up. FMR quantitation, even for volumetrically modest regurgitation, provides incremental prognostic information over AS severity.

Excess Mortality Associated with Progression Rate in Asymptomatic Aortic Valve Stenosis

BACKGROUND

Aortic valve stenosis (AS) is a progressive condition characterized by gradual calcification of the aortic cusps. Progression rate evaluated using echocardiography has been associated with survival. However, data from routine practice covering the whole spectrum of AS severity and the rate of symptom onset are sparse. The aim of this study was to assess outcomes under medical management related to disease progression in asymptomatic patients with a wide range of AS severity.

METHODS

Two hundred twenty-nine consecutive asymptomatic patients (mean age, 77 ± 10 years; 55% men) with AS, preserved left ventricular ejection fraction, and two or more echocardiographic examinations performed from 2004 to 2014 were retrospectively included. The median time between the two echocardiographic examinations was 24 months (interquartile range, 15-46 months). Patients were identified as rapid progressors if the annualized difference in peak aortic velocity between two echocardiographic examinations was ≥0.3 m/sec/y; others were labeled as slow progressors. The primary end point was mortality during medical follow-up (censoring on aortic valve interventions). The secondary end point was overall mortality.

RESULTS

Rapid progressors accounted for 67 of the 229 patients (29%), and this feature was not associated with baseline characteristics. During a median of 5.8 years (interquartile range, 3.4-8.3 years) of follow-up from the first echocardiographic examination, 102 patients (45%) died, 86 (84%) during medical follow-up. Rapid progression rate predicted excess mortality (vs slow progression rate) after adjustment for age, sex, symptoms, baseline left ventricular ejection fraction, and baseline aortic valve area (hazard ratio, 2.50; 95% CI, 1.48-4.21; P = .0006) and after adjusting for peak aortic velocity and left ventricular ejection fraction obtained at the last echocardiographic examination (hazard ratio, 2.07; 95% CI, 1.25-3.46; P = .005). Among patients with baseline peak aortic velocity < 4 m/sec (nonsevere AS), rapid progression rate was associated with higher 5-year mortality compared with slow progression (57% vs 22% [P < .0001] under medical management and 44% vs 18% [P = .005] overall). Outcomes were comparable between nonsevere AS rapid progressors and baseline severe AS. Progression rate showed incremental prognostic value on receiver operating characteristic curve analysis versus AS severity. Of note, among slow progressors, 11 patients (5%) presented with high rates of symptom development and poor outcomes related to ventricular dysfunction or other advanced AS features.

CONCLUSIONS

Progression rate is an individual, almost unpredictable feature among patients with AS. Rapid progression is an incremental marker of excess mortality in asymptomatic patients with AS, independent of clinical and hemodynamic characteristics. Rapid progression rate may identify patients with nonsevere AS at higher risk for events.

The ‘wait for symptoms’ strategy in asymptomatic severe aortic stenosis

Calcific aortic stenosis is a prevalent and worrisome healthcare problem. The therapeutic approach in asymptomatic aortic stenosis is not well established. We argue that the natural history of this disease is based on old incomplete studies with many limitations. Likewise, studies suggesting that replacement, either surgical or percutaneous, improves prognosis in asymptomatic patients with severe aortic stenosis have important drawbacks and do not support this strategy as the treatment of choice. Despite the lack of evidence, some groups recommend early valve replacement in patients with severe asymptomatic aortic stenosis. There are five ongoing randomised trials which will shed light on this topic. Our conclusion is that unless a randomised study changes the evidence, valve replacement cannot be recommended in asymptomatic patients with severe aortic stenosis.

Progression of Normal Flow Low Gradient "Severe" Aortic Stenosis With Preserved Left Ventricular Ejection Fraction

Normal-flow low-gradient severe aortic stenosis (NF-LG-SAS), defined by an aortic valve area (AVA) <1 cm², mean pressure gradient (MPG) <40 mm Hg and indexed stroke volume ≥35 ml/m², is the most prevalent form of low-gradient aortic stenosis (AS) with preserved ejection fraction (PEF). However, the true severity of AS in these patients is controversial. The aim of this Doppler echocardiographic study was to investigate changes over time in the hemodynamic severity of patients with NF-LG-SAS with PEF. We retrospectively identified 96 patients who had 2 Doppler echocardiographic examinations without an intervening event. After a median follow-up of 25 (interquartile range 15 to 52) months, progression was observed, with increased transaortic MPG (from 28 [25 to 33] to 39 [34 to 50] mm Hg; p<0.001), peak aortic jet velocity (from 3.46 [3.20 to 3.64] to 4.01 [3.70 to 4.39] m/s; p<0.001), and decreased AVA (from 0.87 [0.82 to 0.94] to 0.72 [0.62 to 0.81] cm²; p<0.001). Median annual rates of progression were 4.3 (1.7 to 8.1) mm Hg/year, 0.25 (0.08 to 0.44) m/s/year, and -0.05 (-0.10 to -0.02) cm²/year, respectively. There was no significant change in left ventricular ejection fraction over time (p = 0.74). At follow-up, 46 patients (48%) acquired the features of classical high-gradient severe AS (MPG ≥40 mm Hg). This study shows that most patients with NF-LG-SAS with PEF exhibit significant hemodynamic progression of AS severity without EF impairment. These findings suggest that NF-LG-SAS with PEF is an "intermediate" stage between moderate AS and classical high-gradient severe AS requiring close monitoring.

Prevalence, clinical correlates, and burden of undiagnosed aortic stenosis in older patients: a prospective study in a non-cardiologic acute hospital ward

BACKGROUND

The epidemiology of aortic stenosis (AS) in older patients admitted to non-cardiologic acute hospital wards and the effect of AS on mid-term survival are incompletely reported. In a cohort of very old patients admitted to an acute geriatric unit (AGU), we aimed to assess: (1) the prevalence of newly and previously diagnosed AS; and (2) the association between AS severity and patients' 6-month mortality.

METHODS

The patients consecutively admitted in two AGU rooms from February 2016 to February 2018 were assessed with echocardiography and AS severity was defined according to standard criteria. We assessed frailty using a 34-item Frailty Index (34-FI), which was operationalized using health variable information, and the Clinical Frailty Scale (CFS). Vital status at 6 months was extracted from Regional Register of Birth and Death.

RESULTS

Two hundred and three patients (mean age 84.5 ± 6.0 SD, female gender 56.1%) were included. Of these, 57 (28.1%) had AS, mild in 9 (4.5%), moderate in 32 (16.1%) and severe in 16 (8.1%). A new diagnosis of AS was obtained in 42 (73.7%) patients, of whom 33 (78.6%) had moderate or severe AS. At 6 months, 61 (28.9%) patients died. In multiple regression models, after adjusting for covariates, frailty, as assessed with both FI and CFS, was independent predictor of 6-month mortality whereas AS was not.

CONCLUSIONS

Among older patients admitted to non-cardiologic acute hospital wards, AS was common and frequently underdiagnosed. The severity of AS was not associated with increased 6-month mortality, whereas frailty was the most important predictor.

Role of lipoprotein (a) and LPA KIV2 repeat polymorphism in bicuspid aortic valve stenosis and calcification: a proof of concept study

Hemodynamic valvular impairment is a frequent determinant of the natural history of bicuspid aortic valve (BAV). The role of elevated Lp(a) levels and LPA Kringle IV type 2 (KIV-2) size polymorphism in influencing aortic valve calcification and stenosis development in patients with tricuspid aortic valve was recognized. In this study, we investigate the association between Lp(a) and LPA KIV-2 repeat number, and the presence of calcification and stenosis in BAV patients. Sixty-nine patients [79.7% males; median age 45(30-53) yrs], consecutively referred to Center for Cardiovascular Diagnosis or Referral Center for Marfan syndrome or related disorders, AOU Careggi, from June to November 2014, were investigated. For each patient, clinical (ECG and echocardiography) and laboratory [Lp(a) (Immunoturbidimetric assay) and LPA KIV-2 repeat number (real-time PCR)] evaluation were performed. Patients were compared with 69 control subjects. No significant association between Lp(a) circulating levels and LPA KIV-2 repeat number and BAV was evidenced. Among BAV patients, significantly higher Lp(a) levels according to calcification degree were found [no calcifications:78(42-159) mg/L, mild/moderate: 134(69-189) mg/L; severe: 560(286-1511) mg/L, p = 0.008]. Conversely, lower LPA KIV-2 repeat numbers in subjects with more severe calcification degree were observed. Furthermore, higher Lp(a) levels in patients with aortic stenosis [214(67-501) mg/L vs 104(56-169) mg/L, p = 0.043] were also found. In conclusion, present data suggest the potential role for Lp(a) as a possible risk marker useful to stratify, among BAV patients, those with a higher chance to develop valvular calcifications and aortic stenosis.

Predicting Outcomes in Patients With AsymptomaticModerate to Severe Aortic Stenosis

Outcomes in asymptomatic patients with aortic stenosis (AS) have been reported primarily from tertiary centers. Whether observations from a community hospital cohort would be similar or if clinical variables would assume a more important role remains uncertain. This retrospective cohort study from one community hospital followed asymptomatic patients with moderate to severe AS for 3 years following an index echocardiogram. Patients underwent standard echocardiographic imaging and assessment of AS severity. Outcomes included aortic valve replacement, onset of Class 4 heart failure and cardiovascular death. Inclusion or exclusion criteria were met by 190 patients (body mass index of 30.8 ± 7.5 kg/m² and age 70.9 ± 13.0 years). In this obese and racially diverse cohort, adverse outcomes occurred in 72 of 190 (38%), aortic valve replacement in 33 of 72 (46%), heart failure in 30 of 72 (42%), and cardiovascular death in 9 of 72 (13%). Univariate analyses found that the echocardiographic variables assessing AS severity (Vmax, mean aortic valve gradient, and the dimensionless index) were strongly associated with outcomes. A model predicting time to adverse outcomes included age, gender, Charlson index, Vmax, aortic valve area, the electrocardiographic variables of atrial fibrillation and left ventricular strain, and echocardiographic variables unrelated to the direct measurements of stenosis severity. In conclusion, direct echocardiographic measures of AS severity, echocardiographic parameters unrelated to AS severity plus the electrocardiographic variables of atrial fibrillation and left ventricular strain were the dominant predictors of adverse outcomes in a community hospital cohort of asymptomatic patients with moderate to severe AS.

Outcomes in Moderate Mixed Aortic Valve Disease: Is it Time for a Paradigm Shift?

BACKGROUND

A direct comparison of outcomes between moderate mixed aortic valve disease (MAVD) and isolated aortic stenosis (AS) or aortic regurgitation (AR) has not been performed, making evidence-based recommendations difficult in patients with MAVD.

OBJECTIVES

This study sought to determine adverse event (AE) occurrence (the primary endpoint), defined as New York Heart Association functional class III/IV symptoms, aortic valve replacement, or cardiac death, and to compare AE rates between MAVD and isolated AS or AR.

METHODS

Asymptomatic patients were identified with moderate MAVD and an ejection fraction ≥50% and were followed at Mayo Clinic from 1994 to 2013. Moderate MAVD was defined as a combination of moderate AS and moderate AR. Age- and sex-matched control groups were selected with isolated moderate AR (n = 117), moderate AS (n = 117), or severe AS (n = 117).

RESULTS

At 9.1 ± 4.2 years of follow-up, patients with moderate MAVD (n = 251) had a mean age of 63 ± 11 years, 73% were male, and 38% had bicuspid valve. AE occurred in 193 (77%) patients in this group, including symptom development (69%), aortic valve replacement (67%), and cardiac death (4%). Predictors of AE were older age (hazard ratio [HR]: 1.71 per decade; 95% confidence interval [CI]: 1.38 to 1.97 per decade; p = 0.001), and relative wall thickness >0.42 (HR: 2.01; 95% CI: 1.86 to 2.33; p = 0.002). AE rates were similar in the MAVD and severe AS group (71% vs. 68% at 5 years; p = 0.49), but were significantly higher compared with the moderate AS and AR groups.

CONCLUSIONS

MAVD patients had outcomes comparable to those with severe AS, and preserved ejection fraction and should be monitored closely for symptoms.

Feasibility and relevance of right parasternal view for assessing severity and rate of progression of aortic valve stenosis in primary care

BACKGROUND

Right parasternal view (RPV) is important in assessing the severity of aortic stenosis (AS). However, the feasibility and relevance of RPV in primary care is unresolved. Moreover, information regarding the role of RPV in the evaluation of the hemodynamic progression of AS is lacking.

METHODS

Consecutive patients with peak aortic valve velocity (V_max) ≥2.5m/s were prospectively enrolled in a primary care echocardiographic laboratory. Aortic Doppler parameters were evaluated from apical view and RPV.

RESULTS

The total number of enrolled patients was 330 (aged 81±11years, 47% female, left ventricular ejection fraction 64±9%). The RPV was feasible in 275 (83%). V_max and Mean Gradient were significantly higher and aortic valve area was significantly lower from RPV as compared to apical view (p<0.0001 for all). Reclassification of severity towards either moderate or severe AS occurred in 13-26% of patients, according to different criteria, when evaluated from RPV. Among 108 patients (40%) undergoing multiple examinations the rate of progression was lower from the apical approach than from the RPV (0.19±0.20m/s/year vs. 0.24±0.27m/s/year, respectively; p=0.03), and was fast (>0.3m/s/year) in 17 patients (16%) from the apical window vs. 26 patients (24%) from RPV (p<0.0001).

CONCLUSION

Implementing RPV is feasible in primary care and results in a substantial reclassification rate through the entire spectrum of AS severity. Our data also suggest a potential role of Doppler interrogation from multiple windows to improve AS progression assessment.

ANMCO/SIC/SICI-GISE/SICCH Executive Summary of Consensus Document on Risk Stratification in elderly patients with aortic stenosis before surgery or transcatheter aortic valve replacement

Aortic stenosis is one of the most frequent valvular diseases in developed countries, and its impact on public health resources and assistance is increasing. A substantial proportion of elderly people with severe aortic stenosis is not eligible to surgery because of the advanced age, frailty, and multiple co-morbidities. Transcatheter aortic valve implantation (TAVI) enables the treatment of very elderly patients at high or prohibitive surgical risk considered ineligible for surgery and with an acceptable life expectancy. However, a significant percentage of patients die or show no improvement in quality of life (QOL) in the follow-up. In the decision-making process, it is important to determine: (i) whether and how much frailty of the patient influences the risk of procedures; (ii) how the QOL and the individual patient's survival are influenced by aortic valve disease or from other associated conditions; and (iii) whether a geriatric specialist intervention to evaluate and correct frailty or other diseases with their potential or already manifest disabilities can improve the outcome of surgery or TAVI. Consequently, in addition to risk stratification with conventional tools, a number of factors including multi-morbidity, disability, frailty, and cognitive function should be considered, in order to assess the expected benefit of both surgery and TAVI. The pre-operative optimization through a multidisciplinary approach with a Heart Team can counteract the multiple damage (cardiac, neurological, muscular, respiratory, and kidney) that can potentially aggravate the reduced physiological reserves characteristic of frailty. The systematic application in clinical practice of multidimensional assessment instruments of frailty and cognitive function in the screening and the adoption of specific care pathways should facilitate this task.

Relationship between exercise pressure gradient and haemodynamic progression of aortic stenosis

BACKGROUND AND AIMS

We hypothesized that large exercise-induced increases in aortic mean pressure gradient can predict haemodynamic progression during follow-up in asymptomatic patients with aortic stenosis.

METHODS

We retrospectively identified patients with asymptomatic moderate or severe aortic stenosis (aortic valve area<1.5cm² or<1cm²) and normal ejection fraction, who underwent an exercise stress echocardiography at baseline with a normal exercise test and a resting echocardiography during follow-up. The relationship between exercise-induced increase in aortic mean pressure gradient and annualised changes in resting mean pressure gradient during follow-up was investigated.

RESULTS

Fifty-five patients (mean age 66±15 years; 45% severe aortic stenosis) were included. Aortic mean pressure gradient significantly increased from rest to peak exercise (P<0.001). During a median follow-up of 1.6 [1.1-3.2] years, resting mean pressure gradient increased from 35±13mmHg to 48±16mmHg, P<0.0001. Median annualised change in resting mean pressure gradient during follow-up was 5 [2-11] mmHg. Exercise-induced increase in aortic mean pressure gradient did correlate with annualised changes in mean pressure gradient during follow-up (r=0.35, P=0.01). Hemodynamic progression of aortic stenosis was faster in patients with large exercise-induced increase in aortic mean pressure gradient (≥20mmHg) as compared to those with exercise-induced increase in aortic mean pressure gradient<20mmHg (median annualised increase in mean pressure gradient 19 [6-28] vs. 4 [2-10] mmHg/y respectively, P=0.002). Similar results were found in the subgroup of 30 patients with moderate aortic stenosis.

CONCLUSION

Large exercise-induced increases in aortic mean pressure gradient correlate with haemodynamic progression of stenosis during follow-up in patients with asymptomatic aortic stenosis. Further studies are needed to fully establish the role of ESE in the decision-making process in comparison to other prognostic markers in asymptomatic patients with aortic stenosis.

Natural History, Diagnostic Approaches, and Therapeutic Strategies for Patients With Asymptomatic Severe Aortic Stenosis

Aortic stenosis (AS) is one of the most common valvular diseases encountered in clinical practice. Current guidelines recommend aortic valve replacement (AVR) when the aortic valve is severely stenotic and the patient is symptomatic; however, a substantial proportion of patients with severe AS are asymptomatic at the time of first diagnosis. Although specific morphological valve features, exercise testing, stress imaging, and biomarkers can help to identify patients with asymptomatic severe AS who may benefit from early AVR, the optimal management of these patients remains uncertain and controversial. The current report presents a comprehensive review of the natural history and the diagnostic evaluation of asymptomatic patients with severe AS, and is followed by a meta-analysis from reported studies comparing an early AVR strategy to active surveillance, with an emphasis on the level of evidence substantiating the current guideline recommendations. Finally, perspectives on directions for future investigation are discussed.

Prognostic value of NT-proBNP and an adapted monin score in patients with asymptomatic aortic stenosis

INTRODUCTION AND OBJECTIVES

Our objective was to assess the prognostic value of NT-proBNP in patients with asymptomatic moderate/severe aortic stenosis and to validate an adapted Monin score using natriuretic peptide levels in our setting.

METHODS

Prospective study of 237 patients with degenerative asymptomatic moderate/severe aortic stenosis. NT-proBNP was determined in all patients, who were then followed up clinically. The adapted Monin score was defined as follows: (peak velocity [m/s]×2)+(logn NT-proBNP×1.5)(+1.5 if woman). A clinical event was defined as surgery, hospital admission due to angina, heart failure or syncope, or death.

RESULTS

A total of 51% were women, and the mean age was 74 years. Mean (SD) echocardiographic values were as follows: peak velocity 4.14 (0.87) m/s; mean gradient, 43.2 (16.0) mmHg; aortic valve area, 0.87 (0.72) cm(2), and aortic valve area index, 0.49 (0.14) cm(2)/m(2). The median NT-pro-BNP value was 490.0 [198.0-1312.0] pg/mL. There were 153 events during follow-up (median 18 months). The optimum NT-proBNP cut-point was 515 pg/mL, giving event-free survival rates at 1 and 2 years of 93% and 57%, respectively, in patients with NT-proBNP <515 pg/mL compared with 50% and 31% in those with NT-proBNP >515 pg/mL. Patients were divided into quartiles based on the Monin score. Event-free survival at 1 and 2 years was 87% and 79% in the first quartile, compared with 45% and 28% in the fourth quartile, respectively.

CONCLUSIONS

NT-proBNP determination provides prognostic information in patients with asymptomatic moderate/severe aortic stenosis. The adapted Monin score is useful in our setting and allows a more precise prognosis than does the use of NT-proBNP alone.

Current management of calcific aortic stenosis

Calcific aortic stenosis is a progressive disease with no effective medical therapy that ultimately requires aortic valve replacement (AVR) for severe valve obstruction. Echocardiography is the primary diagnostic approach to define valve anatomy, measure aortic stenosis severity, and evaluate the left ventricular response to chronic pressure overload. In asymptomatic patients, markers of disease progression include the degree of leaflet calcification, hemodynamic severity of stenosis, adverse left ventricular remodeling, reduced left ventricular longitudinal strain, myocardial fibrosis, and pulmonary hypertension. The onset of symptoms portends a predictably high mortality rate unless AVR is performed. In symptomatic patients, AVR improves symptoms, improves survival, and, in patients with left ventricular dysfunction, improves systolic function. Poor outcomes after AVR are associated with low-flow low-gradient aortic stenosis, severe ventricular fibrosis, oxygen-dependent lung disease, frailty, advanced renal dysfunction, and a high comorbidity score. However, in most patients with severe symptoms, AVR is lifesaving. Bioprosthetic valves are recommended for patients aged >65 years. Transcatheter AVR is now available for patients with severe comorbidities, is recommended in patients who are deemed inoperable, and is a reasonable alternative to surgical AVR in high-risk patients.

Viewpoint: the ENIGMAS trial - when should we treat patients with moderate aortic stenosis?

Aortic stenosis (AS) is the most frequent valvular heart disease encountered in our daily practice. Although there are clear guidelines for severe AS management, cardiologists often have few treatment options for patients with moderate AS; however, there is higher mortality in this patient subgroup versus an age-matched population. The authors reviewed all of the studies on moderate AS, summarized the factors that increase disease progression and discussed an ideal trial design to prospectively evaluate AS progression factors using modern cardiology tools such as strain and magnetic resonance imaging.

Effect of electrical stimulus parameters on the development and propagation of action potentials in short excitable fibres

Intracellular action potentials (IAPs) produced by short fibres in response to their electrical stimulation were analysed. IAPs were calculated on the basis of the Hodgkin-Huxley (1952) model by the method described by Joyner et al. (1978). Principal differences were found in processes of activation of short (semilength L less than 5 lambda) and long fibres under near-threshold stimulation. The shorter the fibre, the lower was the threshold value (Ithr). Dependence of the latency on the stimulus strength (Ist) was substantially non-linear and was affected by the fibre length. Both fibre length and stimulus strength influenced the IAP amplitude, the instantaneous propagation velocity (IPV) and the site of the first origin of the IAP (and, consequently, excitability of the short fibre membrane). With L less than or equal to 2 lambda and Ithr less than or equal to Ist less than or equal to 1.1Ithr, IPV could reach either very high values (so that all the fibre membrane fired practically simultaneously) or even negative values. The latter corresponded to the first origin of the propagated IAP, not at the site of stimulation but at the fibre termination or at a midpoint. The characters of all the above dependencies were unchanged irrespective of the manner of approaching threshold (variation of stimulus duration or its strength). Reasons for differences in processes of activation of short and long fibres are discussed in terms of electrical load and latency. Applications of the results to explain an increased jitter, velocity recovery function and velocity-diameter relationship are also discussed.