Aortic valve stenosis in community medical practice: Determinants of outcome and implications for aortic valve replacement

Severe aortic stenosis: secular trends of incidence and outcomes

BACKGROUND AND AIMS

Severe aortic stenosis (AS) is the guideline-based indication for aortic valve replacement (AVR), which has markedly increased with transcatheter approaches, suggesting possible increasing AS incidence. However, reported secular trends of AS incidence remain contradictory and lack quantitative Doppler echocardiographic ascertainment.

METHODS

All adults residents in Olmsted County (MN, USA) diagnosed over 20 years (1997-2016) with incident severe AS (first diagnosis) based on quantitatively defined measures (aortic valve area ≤ 1 cm2, aortic valve area index ≤ 0.6 cm2/m2, mean gradient ≥ 40 mmHg, peak velocity ≥ 4 m/s, Doppler velocity index ≤ 0.25) were counted to define trends in incidence, presentation, treatment, and outcome.

RESULTS

Incident severe AS was diagnosed in 1069 community residents. The incidence rate was 52.5 [49.4-55.8] per 100 000 patient-year, slightly higher in males vs. females and was almost unchanged after age and sex adjustment for the US population 53.8 [50.6-57.0] per 100 000 residents/year. Over 20 years, severe AS incidence remained stable (P = .2) but absolute burden of incident cases markedly increased (P = .0004) due to population growth. Incidence trend differed by sex, stable in men (incidence rate ratio 0.99, P = .7) but declining in women (incidence rate ratio 0.93, P = .02). Over the study, AS clinical characteristics remained remarkably stable and AVR performance grew and was more prompt (from 1.3 [0.1-3.3] years in 1997-2000 to 0.5 [0.2-2.1] years in 2013-16, P = .001) but undertreatment remained prominent (>40%). Early AVR was associated with survival benefit (adjusted hazard ratio 0.55 [0.42-0.71], P < .0001). Despite these improvements, overall mortality (3-month 8% and 3-year 36%), was swift, considerable and unabated (all P ≥ .4) throughout the study.

CONCLUSIONS

Over 20 years, the population incidence of severe AS remained stable with increased absolute case burden related to population growth. Despite stable severe AS presentation, AVR performance grew notably, but while declining, undertreatment remained substantial and disease lethality did not yet decline. These population-based findings have important implications for improving AS management pathways.

Normal-Flow Low-Gradient Aortic Stenosis: Comparing the U.S. and European Guidelines

Patients with normal-flow low-gradient (NFLG) severe aortic stenosis present both diagnostic and management challenges, with debate about the whether this represents true severe stenosis and the need for valve replacement. Studies exploring the natural history without intervention have shown similar outcomes of patients with NFLG severe aortic stenosis to those with moderate aortic stenosis and better outcomes after valve replacement than those with low-flow low-gradient severe aortic stenosis. Most studies (all observational) have shown that aortic valve replacement was associated with a survival benefit vs surveillance. Based on available data, the European Society of Cardiology/European Association for Cardio-Thoracic Surgery guidelines and European Association of Cardiovascular Imaging/American Society of Echocardiography suggest that these patients are more likely to have moderate aortic stenosis. This clinical entity is not mentioned in the American Heart Association/American College of Cardiology guidelines. Here we review the definition of NFLG severe aortic stenosis, potential diagnostic algorithms and points of error, the data supporting different management strategies, and the differing guidelines and outline the unanswered questions in the diagnosis and management of these challenging patients.

Aortic Valve Calcium Score by Computed Tomography as an Adjunct to Echocardiographic Assessment-A Review of Clinical Utility and Applications

Aortic valve stenosis (AS) is increasing in prevalence due to the aging population, and severe AS is associated with significant morbidity and mortality. Echocardiography remains the mainstay for the initial detection and diagnosis of AS, as well as for grading of severity. However, there are important subgroups of patients, for example, patients with low-flow low-gradient or paradoxical low-gradient AS, where quantification of severity of AS is challenging by echocardiography and underestimation of severity may delay appropriate management and impart a worse prognosis. Aortic valve calcium score by computed tomography has emerged as a useful clinical diagnostic test that is complimentary to echocardiography, particularly in cases where there may be conflicting data or clinical uncertainty about the degree of AS. In these situations, aortic valve calcium scoring may help re-stratify grading of severity and, therefore, further direct clinical management. This review presents the evolution of aortic valve calcium score by computed tomography, its diagnostic and prognostic value, as well as its utility in clinical care.

An alternative method of indexation in aortic stenosis: height-adjusted effective orifice area : An observational prospective study

BACKGROUND

Although indexing effective orifice area (EOA) by body surface area (BSA) is recommended, this method has several disadvantages, since it corrects by acquired fatty tissue. Our aim was to analyze the value of EOA normalized by height for predicting cardiovascular outcome in patients with aortic stenosis (AS).

METHODS

Patients with AS (peak velocity > 2 m/s) evaluated in our echocardiography laboratory between January 2015 and June 2018 were prospectively enrolled. EOA was indexed by BSA and height. A composite primary endpoint was defined as cardiac death or aortic valve replacement. A receiver operating characteristic curve was plotted to determine the best cutoff value of EOA/height for predicting cardiovascular events.

RESULTS

Four-hundred and fifteen patients were included (52% women, mean age 74.8 ± 11.6 years). Area under the curve was similar for EOA/BSA (AUC 0.75, p < 0.001) and EOA/height (AUC 0.75, p < 0.001). A cutoff value of 0.60 cm2/m for EOA/height had a sensitivity of 84%, specificity of 61%, positive predictive value of 60% and negative predictive value of 84%. One-year survival from primary endpoint was significantly lower in patients with EOA/height ≤ 0.60 cm2/m (48 ± 5% vs 91 ± 4%, log-rank p < 0.001) than EOA/height > 0.60 cm2/m. The excess of risk of cardiovascular events seen in univariate analysis persists even after adjustment for other demonstrated adverse prognostic variables (HR 5.91, 95% CI 3.21-10.88, p < 0.001). In obese patients, there was an excess of risk in patients with EOA/height < 0.60 cm2/m (HR 10.2, 95% CI 3.5-29.5, p < 0.001), but not in EOA/BSA < 0.60 cm2/m2 (HR 0.14, 95% CI 0.14-1.4, p = 0.23).

CONCLUSIONS

We could identify a subgroup of patients with AS at high risk of cardiovascular events. Consequently, we recommend using EOA/height as a method of indexation in AS, especially in obese patients, with a cutoff of 0.60 cm2/m for identifying patients with higher cardiovascular risk.

Impact of Managing Provider Type on Severe Aortic Stenosis Management and Mortality

Background Many patients with symptomatic severe aortic stenosis do not undergo aortic valve replacement (AVR) despite clinical guidelines. This study analyzed the association of managing provider type with cardiac specialist follow-up, AVR, and mortality for patients with newly diagnosed severe aortic stenosis (sAS). Methods and Results We identified adults with newly diagnosed sAS per echocardiography performed between January 2017 and March 2019 using Optum electronic health record data. We then selected from those meeting all eligibility criteria patients managed by a primary care provider (n=1707 [25%]) or cardiac specialist (n=5039 [75%]). We evaluated the association of managing provider type with cardiac specialist follow-up, AVR, and mortality, as well as the independent association of cardiac specialist follow-up and AVR with mortality, within 1 year of echocardiography detecting sAS. A subgroup analysis was limited to patients with symptomatic sAS. Patient characteristics and comorbidities at baseline were used for covariate-adjusted cause-specific and multivariable Cox proportional hazard models assessing group differences in outcomes by managing provider type. An adjusted Cox proportional hazard model with additional time-dependent covariates for follow-up and AVR was used to assess these practices' association with mortality. Within 1 year of echocardiography detecting sAS, data revealed that primary care provider management was associated with lower rates of cardiac specialist follow-up (hazard ratio [HR], 0.47 [95% CI, 0.43-0.50], P<0.0001) and AVR (HR, 0.58 [95% CI, 0.53-0.64], P<0.0001) and with higher 1-year mortality (HR, 1.45 [95% CI, 1.26-1.66], P<0.0001). Cardiac specialist follow-up and AVR were independently associated with lower mortality (follow-up: HR, 0.55 [95% CI, 0.48-0.63], P<0.0001; AVR: HR, 0.70 [95% CI, 0.60-0.83], P<0.0001). Results were similar for patients with symptomatic sAS. All analyses were adjusted for baseline patient characteristics and comorbidities. Conclusions For patients newly diagnosed with sAS, we observed differences in rates of cardiac specialist follow-up and AVR and risk of mortality between primary care provider- versus cardiologist-managed patients with sAS. In addition, a lower likelihood of receiving follow-up and AVR was independently associated with higher mortality.

Outcomes in Patients With Obstructive Hypertrophic Cardiomyopathy and Concomitant Aortic Stenosis Undergoing Surgical Myectomy and Aortic Valve Replacement

Background Hypertrophic cardiomyopathy (HCM) and aortic stenosis can cause obstruction to the flow of blood out of the left ventricular outflow tract into the aorta, with obstructive HCM resulting in dynamic left ventricular outflow tract obstruction and moderate or severe aortic stenosis causing fixed obstruction caused by calcific degeneration. We sought to report the characteristics and longer-term outcomes of patients with severe obstructive HCM who also had concomitant moderate or severe aortic stenosis requiring surgical myectomy and aortic valve replacement. Methods and Results We studied 191 consecutive patients (age 67±6 years, 52% men) who underwent myectomy and aortic valve (AV) replacement (90% bioprosthesis) at our center between June 2002 and June 2018. Clinical and echo data including left ventricular outflow tract gradient and indexed AV area were recorded. The primary outcome was death. Prevalence of hypertension (63%) and hyperlipidemia (75%) were high, with a Society of Thoracic Surgeons score of 5±4, and 70% of participants had no HCM-related sudden death risk factors. Basal septal thickness and indexed AV area were 1.9±0.4 cm and 0.72±0.2 cm²/m², respectively, while 100% of patients had dynamic left ventricular outflow tract gradient >50 mm Hg. At 6.5±4 years, 52 (27%) patients died (1.5% in-hospital deaths). One-, 2-, and 5-year survival in the current study sample was 94%, 91%, and 83%, respectively, similar to an age-sex-matched general US population. On multivariate Cox survival analysis, age (hazard ratio [HR], 1.65; 95% CI, 1.24-2.18), chronic kidney disease (HR, 1.58; 95% CI, 1.21-2.32), and right ventricular systolic pressure on preoperative echocardiography (HR, 1.28; 95% CI, 1.05-1.57) were associated with longer-term mortality, but traditional HCM risk factors did not. Conclusions In symptomatic patients with severely obstructive HCM and moderate or severe aortic stenosis undergoing a combined surgical myectomy and AV replacement at our center, the observed postoperative mortality was significantly lower than the expected mortality, and the longer-term survival was similar to a normal age-sex-matched US population.

Size-adjusted aortic valve area: refining the definition of severe aortic stenosis

AIMS

Severe aortic valve stenosis (AS) is defined by an aortic valve area (AVA) <1 cm2 or an AVA indexed to body surface area (BSA) <0.6 cm/m2, despite little evidence supporting the latter approach and important intrinsic limitations of BSA indexation. We hypothesized that AVA indexed to height (H) might be more applicable to a wide range of populations and body morphologies and might provide a better predictive accuracy.

METHODS AND RESULTS

In 1298 patients with degenerative AS and preserved ejection fraction from three different countries and continents (derivation cohort), we aimed to establish an AVA/H threshold that would be equivalent to 1.0 cm2 for defining severe AS. In a distinct prospective validation cohort of 395 patients, we compared the predictive accuracy of AVA/BSA and AVA/H. Correlations between AVA and AVA/BSA or AVA/H were excellent (all R2 > 0.79) but greater with AVA/H. Regressions lines were markedly different in obese and non-obese patients with AVA/BSA (P < 0.0001) but almost identical with AVA/H (P = 0.16). AVA/BSA values that corresponded to an AVA of 1.0 cm2 were markedly different in obese and non-obese patients (0.48 and 0.59 cm2/m2) but not with AVA/H (0.61 cm2/m for both). Agreement for the diagnosis of severe AS (AVA < 1 cm2) was significantly higher with AVA/H than with AVA/BSA (P < 0.05). Similar results were observed across the three countries. An AVA/H cut-off value of 0.6 cm2/m [HR = 8.2(5.6-12.1)] provided the best predictive value for the occurrence of AS-related events [absolute AVA of 1 cm2: HR = 7.3(5.0-10.7); AVA/BSA of 0.6 cm2/m2 HR = 6.7(4.4-10.0)].

CONCLUSION

In a large multinational/multiracial cohort, AVA/H was better correlated with AVA than AVA/BSA and a cut-off value of 0.6 cm2/m provided a better diagnostic and prognostic value than 0.6 cm2/m2. Our results suggest that severe AS should be defined as an AVA < 1 cm2 or an AVA/H < 0.6 cm2/m rather than a BSA-indexed value of 0.6 cm2/m2.

Impact of Systolic Blood Pressure on Heart Failure Symptoms With Moderate Aortic Stenosis

In patients with moderate aortic stenosis (AS), heart failure (HF) symptoms are often unrelated to the AS severity, and the causes of HF symptoms are often unclear. Hypertension is known as one of the most common comorbidities in degenerative AS. Therefore, we assessed the impact of systolic blood pressure (BP) on HF symptoms in patients with moderate AS. We retrospectively analyzed 317 patients with moderate AS (mean transaortic pressure gradient 20 to 39 mm Hg) and preserved left ventricular ejection fraction (left ventricular ejection fraction ≥50%). We classified patients according to the presence or absence of HF symptoms. One hundred patients (32%) had HF symptoms. Symptomatic patients had higher systolic BP (141±21 versus 129±21 mm Hg; p<0.001) and mean transaortic pressure gradient, and lower aortic valve area than asymptomatic patients. In the multivariable analysis after adjustment for age, atrial fibrillation, Charlson comorbidity index, brain natriuretic peptide, and the use of diuretics, HF symptoms in patients with moderate AS were independently associated with systolic BP (odds ratio, 1.43 per 10 mm Hg increase in systolic BP; 95% confidence interval, 1.14-1.78; p=0.001) and left atrial volume index (odds ratio, 1.04 per 1 mL/m² increase in left atrial volume index; 95% confidence interval, 1.00-1.08; p=0.026). Receiver operating characteristics curve analysis identified systolic BP 133 mm Hg as the cutoff value associated with HF symptoms. In conclusion, systolic BP as well as left atrial volume index were independent correlates of HF symptoms in patients with moderate AS.

Clinical impact of mitral regurgitation in aortic valve stenosis: Insight from effective regurgitant orifice area

PURPOSE

Mechanisms leading to heart failure (HF) symptoms in aortic valve stenosis (AS) are contentious. We examined the impact of secondary mitral regurgitation (MR) on the symptomatic status in patients with AS.

METHODS

Outpatients performing echocardiography with any degree of AS, without organic mitral valve disease, mitral valve intervention, or aortic insufficiency were enrolled. MR was quantitatively defined through mitral effective regurgitant orifice area (EROA) using the proximal isovelocity surface area method. Patients were divided into two groups (New York Heart Association [NYHA] class I-II vs. NYHA class III-IV).

RESULTS

Five hundred and eighty-four patients were enrolled (484 NYHA I-II, 100 NYHA III-IV). More symptomatic patients had smaller aortic valve area (AVA), lower left ventricular ejection fraction (LVEF) and stroke volume, higher E/E', and LV global afterload. MR was present in 178 (30%) patients and EROA was <.20 cm² in 158 (89%). NYHA III-IV patients showed higher prevalence of MR (78% vs 21%, P < 0.0001) and larger EROA (.13±.08 cm² vs .09±.07 cm² , P < 0.0001). An association between EROA and symptoms was present in the total cohort and in subgroups with preserved LVEF, AVA ≥ 1 and <1 cm² , EE' 8-14 and ≥14 (P < 0.05 for all). EROA was associated with severe symptoms after adjustment for LVEF, E/E', and AVA in the overall population (OR 1.10 [1.06-1.15]; P < 0.0001) and in the 516 patients with preserved LVEF (OR 1.13 [1.08-1.19]; P < 0.0001).

CONCLUSION

In patients with AS, greater EROA values are associated with HF symptoms, even though MR degree is far from the threshold of MR severity. Therefore, even a mild MR represents a supportive marker of HF symptoms presence.

High Prevalence of Severe Aortic Stenosis in Low-Flow State Associated With Atrial Fibrillation

BACKGROUND

Atrial fibrillation (AF) is a low-flow state and may underestimate aortic stenosis (AS) severity. Single-high Doppler signals (HS) consistent with severe AS (peak velocity ≥4 m/s or mean gradient ≥40 mm Hg) are averaged down in current practice. The objective for the study was to determine the significance of HS in AF low-gradient AS (LGAS).

METHODS

One thousand five hundred forty-one patients with aortic valve area ≤1 cm² and left ventricular ejection fraction ≥50% were identified and classified as high-gradient AS (HGAS) (≥40 mm Hg) and LGAS (<40 mm Hg), and AF versus sinus rhythm (SR). Available computed tomography aortic valve calcium scores (AVCS) were retrieved from the medical record. Outcomes were assessed.

RESULTS

Mean age was 76±11 years, female 47%. Mean gradient was 51±12 in SR-HGAS, 48±10 in AF-HGAS, 31±5 in SR-LGAS, and 29±7 mm Hg in AF-LGAS, all P≤0.001 versus SR-HGAS; HS were present in 33% of AF-LGAS. AVCS were available in 34%. Compared with SR-HGAS (2409 arbitrary units; interquartile range, 1581-3462) AVCS were higher in AF-HGAS (2991 arbitrary units; IQR1978-4229, P=0.001), not different in AF-LGAS (2399 arbitrary units; IQR1817-2810, P=0.47), and lower in SR-LGAS (1593 arbitrary units; IQR945-1832, P<0.001); AVCS in AF-LGAS were higher when HS were present (P=0.048). Compared with SR-HGAS, the age-, sex-, comorbidity index-, and time-dependent aortic valve replacement-adjusted mortality risk was higher in AF-HGAS (hazard ratio=1.82 [1.40-2.36], P<0.001) and AF-LGAS with HS (hazard ratio=1.54 [1.04-2.26], P=0.03) but not different in AF-LGAS without HS or SR-LGAS (both P=not significant).

CONCLUSIONS

Severe AS was common in AF-LGAS. AVCS in AF-LGAS were not different from SR-HGAS. AVCS were higher and mortality worse in AF-LGAS when HS were present.

Echocardiographic assessment of aortic stenosis: a practical guideline from the British Society of Echocardiography

The guideline provides a practical step-by-step guide in order to facilitate high-quality echocardiographic studies of patients with aortic stenosis. In addition, it addresses commonly encountered yet challenging clinical scenarios and covers the use of advanced echocardiographic techniques, including TOE and Dobutamine stress echocardiography in the assessment of aortic stenosis.

Association between multimodality measures of aortic stenosis severity and quality-of-life improvement outcomes after transcatheter aortic valve replacement

AIMS

Up to 40% of patients with aortic stenosis (AS) present with discordant grading of AS severity based on common transthoracic echocardiography (TTE) measures. Our aim was to evaluate the utility of TTE and multi-detector computed tomography (MDCT) measures in predicting symptomatic improvement in patients with AS undergoing transcatheter aortic valve replacement (TAVR).

METHODS AND RESULTS

A retrospective review of 201 TAVR patients from January 2017 to November 2018 was performed. Pre- and post-intervention quality-of-life was measured using the Kansas City Cardiomyopathy Questionnaire (KCCQ-12). Pre-intervention measures including dimensionless index (DI), stroke volume index (SVI), mean transaortic gradient, peak transaortic velocity, indexed aortic valve area (AVA), aortic valve calcium score, and AVA based on hybrid MDCT-Doppler calculations were obtained and correlated with change in KCCQ-12 at 30-day follow-up. Among the 201 patients studied, median KCCQ-12 improved from 54.2 pre-intervention to 85.9 post-intervention. In multivariable analysis, patients with a mean gradient >40 mmHg experienced significantly greater improvement in KCCQ-12 at follow-up than those with mean gradient ≤40 mmHg (28.1 vs. 16.4, P = 0.015). Patients with MDCT-Doppler-calculated AVA of ≤1.2 cm2 had greater improvements in KCCQ-12 scores than those with computed tomography-measured AVA of >1.2 cm2 (23.4 vs. 14.1, P = 0.049) on univariate but not multivariable analysis. No association was detected between DI, SVI, peak velocity, calcium score, or AVA index and change in KCCQ-12.

CONCLUSION

Mean transaortic gradient is predictive of improvement in quality-of-life after TAVR. This measure of AS severity may warrant greater relative consideration when selecting the appropriateness of patients for TAVR.

The association between aortic valve calcification, cardiovascular risk factors, and cardiac size and function in a general population

To determine the presence and extent of aortic valve calcification (AVC) quantified by non-contrast cardiac computed tomography (NCCT), to determine the association between traditional cardiovascular risk factors and AVC score, and to evaluate the association between AVC and cardiac size and function assessed by echocardiography, in a general population aged 65-75 years. A random sample of 2060 individuals were invited to undergo NCCT through which their AVC score was assessed. Individuals with an AVC score ≥ 300 arbitrary units (AU) were invited for a transthoracic echocardiography together with age-matched controls. Descriptive statistics and multiple regression analyses were performed to identify risk factors associated with AVC and to describe associations between AVC score and echocardiographic findings. Of 2060 individuals invited 664 males and 636 females participated. Among those, 455 (68.5%) of males and 358 (56.3%) of females had AVC scores > 0 AU. The median AVC score was 6 AU (IQR 0-3064). Seventy-seven (11.6%) males and 20 (3.1%) females had an AVC score ≥ 300 AU. In a multiple regression analysis, age, sex, prior cardiovascular disease, smoking, and hypertension were associated with AVC score, while diabetes, hypercholesterolemia and kidney function were not. Individuals with AVC ≥ 300 AU had higher peak and mean aortic valve gradient, smaller indexed aortic valve area, greater left ventricular mass, and larger left atrial (LA) volume. In a random population sample of individuals aged 65-75 years, AVC was common and associated with most known cardiovascular risk factors. AVC ≥ 300 AU was associated with concentric remodeling and LA dilatation.

Characterisation of aortic stenosis severity: a retrospective analysis of echocardiography reports in a clinical laboratory

Objective

To evaluate how common echocardiographic metrics of aortic stenosis (AS) influence the proportion of patients who may be categorised as having severe stenosis and therefore considered for valve replacement.

Methods

Retrospective analysis was performed of all echocardiograms with aortic valve area (AVA) ≤1.2 cm² and peak jet velocity (V_max) ≥3 m/s from 1 December 2014 through 30 October 2017 at a single academic medical centre. Echocardiographic indices collected include AVA, V_max, left ventricular ejection fraction, stroke volume and annotated aortic stenosis severity.

Results

Among 807 patients with AVA ≤1.2 cm² and V_max ≥3 m/s (44.0% female, median age 74 years (IQR: 66–81)), 45.6% had V_max ≥4 m/s, while 75.8% had AVA ≤1 cm². 40.0% of patients had concordant indices (V_max ≥4 m/s and AVA ≤1 cm²), and 35.8% had discordant indices (V_max <4 m/s and AVA ≤1 cm²) of severe AS. Compared with those with concordant indices, patients with discordant indices were more commonly female (54.0% vs 44.3%, p<0.05) and less commonly characterised as severe (42.6% vs 93.8%, p<0.001). Patients with paradoxical low-flow, low-gradient severe AS by echocardiography were disproportionately female (61.5% vs 41.8%, p<0.001), and their disease was characterised as severe only 49.5% of the time.

Conclusions

Patients with discordant indices, who are disproportionately female, are commonly described in clinical echocardiography reports as having less than severe AS. Given the potential benefit of AVR in patients with AVA ≤1 cm² regardless of V_max, this could have important clinical implications.

Prognostic Impact of Aortic Valve Area in Conservatively Managed Patients With Asymptomatic Severe Aortic Stenosis With Preserved Ejection Fraction

Background

Data are scarce on the role of aortic valve area (AVA) to identify those patients with asymptomatic severe aortic stenosis (AS) who are at high risk of adverse events. We sought to explore the prognostic impact of AVA in asymptomatic patients with severe AS in a large observational database.

Methods and Results

Among 3815 consecutive patients with severe AS enrolled in the CURRENT AS (Contemporary Outcomes After Surgery and Medical Treatment in Patients With Severe Aortic Stenosis) registry, the present study included 1309 conservatively managed asymptomatic patients with left ventricular ejection fraction ≥50%. The study patients were subdivided into 3 groups based on AVA (group 1: AVA >0.80 cm², N=645; group 2: 0.8 cm² ≥AVA >0.6 cm², N=465; and group 3: AVA ≤0.6 cm², N=199). The prevalence of very severe AS patients (peak aortic jet velocity ≥5 m/s or mean aortic pressure gradient ≥60 mm Hg) was 2.0%, 5.8%, and 26.1% in groups 1, 2, and 3, respectively. The cumulative 5‐year incidence of AVR was not different across the 3 groups (39.7%, 43.7%, and 39.9%; P=0.43). The cumulative 5‐year incidence of the primary outcome measure (a composite of aortic valve–related death or heart failure hospitalization) was incrementally higher with decreasing AVA (24.1%, 29.1%, and 48.1%; P<0.001). After adjusting for confounders, the excess risk of group 3 and group 2 relative to group 1 for the primary outcome measure remained significant (hazard ratio, 2.21, 95% CI, 1.56–3.11, P<0.001; and hazard ratio, 1.34, 95% CI, 1.01–1.78, P=0.04, respectively).

Conclusions

AVA ≤0.6 cm² would be a useful marker to identify those high‐risk patients with asymptomatic severe AS, who might benefit from early AVR.

Clinical Trial Registration

URL: www.umin.ac.jp. Unique identifier: UMIN000012140.

See Editorial by Tribouilloy et al

Left ventricular filling pressure and survival following aortic valve replacement for severe aortic stenosis

OBJECTIVE

To determine whether echocardiography-derived left ventricular filling pressure influences survival in patients with severe aortic stenosis (AS) undergoing aortic valve replacement (AVR).

METHODS

We retrospectively reviewed 1383 consecutive patients with severe AS, normal ejection fraction and interpretable filling pressure undergoing AVR. Left ventricular filling pressure was determined according to current guidelines using mitral inflow, mitral annular tissue Doppler, estimated right ventricular systolic pressure and left atrial volume index. Cox proportional hazards regression was used to assess the influence of various parameters on mortality.

RESULTS

Age was 75±10 years and 552 (40%) were female. Left ventricular filling pressure was normal in 325 (23%), indeterminate in 463 (33%) and increased in 595 (43%). Mean follow-up was 7.3±3.7 years, and mortality was 1.2%, 4.2% and 18.9% at 30 days and 1 and 5 years, respectively. Compared with patients with normal filling pressure, patients with increased filling pressure were older (78±9 vs 70±12, p<0.001), more often female (45% vs 35%, p=0.002) and were more likely to have New York Heart Association class III-IV symptoms (35% vs 24%, p=0.004), coronary artery disease (55% vs 42%, p<0.001) and concentric left ventricular hypertrophy (63% vs 37%, p<0.001). After correction for other factors, increased left ventricular filling pressure remained an independent predictor of mortality after successful AVR (adjusted HR 1.45 (95% CI 1.16 to 1.81), p=0.005).

CONCLUSIONS

Preoperative increased left ventricular filling pressure is common in patients with AS undergoing AVR and has important prognostic implications, regardless of symptom status. Future prospective studies should consider whether patients with increased filling pressure would benefit from earlier operation.

Moderate Aortic Stenosis and Heart Failure With Reduced Ejection Fraction: Can Imaging Guide Us to Therapy?

Clinical management of patients with only moderate aortic stenosis (AS) but symptoms of heart failure with a reduced left ventricular ejection fraction (HFrEF) is challenging. Current guidelines recommend clinical surveillance with multimodality imaging; aortic valve replacement (AVR) is deferred until the stenosis becomes severe. Given the known benefits of afterload reduction in management of patients with HFrEF, it has been hypothesized that AVR may be beneficial in patients with only moderate AS who present with HFrEF. In this article, we first review the current approach for management of patients with moderate AS and HFrEF based on close clinical and imaging surveillance with AVR delayed until AS is severe. We then discuss the case for transcatheter AVR (TAVR) earlier in the disease course, when AS is moderate, based on stress echocardiographic data. We conclude with a detailed summary of the TAVR UNLOAD (Transcatheter Aortic Valve Replacement to UNload the Left Ventricle in Patients With ADvanced Heart Failure) trial, in which patients with moderate AS and HFrEF are randomized to guideline-directed heart failure therapy alone versus guideline-directed heart failure therapy plus TAVR.

Prognostic value of aortic valve area normalized to body size in native aortic stenosis

INTRODUCTION AND OBJECTIVES

Although guidelines recommend the use of a cutoff value of 0.60 cm²/m² for aortic valve area (AVA) normalized to body surface area (BSA) for severe aortic stenosis, there is little evidence of its prognostic value. Our aim was to test the value of AVA normalized to body size for outcome prediction in aortic stenosis.

METHODS

One-hundred and ninety patients with at least moderate aortic stenosis (AVA <1.50 cm²) were prospectively enrolled. AVA was normalized to BSA and height. The primary endpoint was cardiovascular death under medical management. A receiver operating characteristic curve was plotted to determine the best cutoff value for predicting cardiovascular death.

RESULTS

An AVA/BSA cutoff value of 0.50 had a sensitivity of 96% and specificity of 51%. An AVA/height cutoff value of 0.49 showed a sensitivity of 96% and a specificity of 52%. During a mean follow-up of 247±190 days, there were 24 cardiovascular deaths, with higher cardiovascular mortality in patients with AVA/BSA <0.50 cm²/m² (21% vs 2.5%, P <.001) and AVA/height <0.49 cm²/m (25% vs 12%, P <.001). Two-year survival was 95±5% in patients with AVA/BSA> 0.50 cm²/m² and was 37±5% in patients with AVA/BSA <0.50 cm²/m² (P <.001). Cardiovascular death risk was higher in patients with AVA/BSA <0.50 cm²/m² (adjusted 10.9 [1.2-103.7], P=.037), but cardiovascular mortality was not significantly higher in multivariate analysis for patients with AVA/height <0.49 cm²/m (2.0 [0.6-6.0], P=.22).

CONCLUSIONS

We could identify a subgroup of patients at high risk of cardiovascular death when they were medically treated. Consequently we recommend using an AVA/BSA cutoff value of 0.50 cm²/m² to identify a subgroup of patients with higher cardiovascular risk.

Novel Echocardiographic Parameters in Patients With Aortic Stenosis and Preserved Left Ventricular Systolic Function Undergoing Surgical Aortic Valve Replacement

We sought to study the incremental prognostic impact of baseline valvuloarterial impedance (Zva) and left ventricular global longitudinal strain (LV-GLS) in patients with severe aortic stenosis and preserved left ventricular ejection fraction (LVEF) treated with surgical aortic valve replacement (AVR). We included 961 consecutive patients (68 ± 13 years; 63% men) with severe aortic stenosis (indexed aortic valve area <0.6 cm²) and LVEF >50% who underwent surgical AVR at our institution between January 2007 and December 2008. The analysis is based on derivation (n = 637) and validation (n = 324) subgroups. Society of Thoracic Surgeons (STS) score was calculated. Zva (systolic arterial pressure + mean aortic valve gradient)/left ventricular stroke volume index and LV-GLS (measured offline using Velocity Vector Imaging; Siemens Medical Solutions, Mountain View, California) were calculated. The primary outcome was death. Median Zva and LV-GLS were 4.5 mm Hg × ml^-1× m² and -14.5%, respectively. AVR was performed at a median of 34 days from initial evaluation (isolated AVR in 46%, bioprosthetic AVR in 93%). At 7.5 ± 3 years, 320 patients died (33%; 30 days/in-hospital death in 0.5%). In the derivation subgroup, on multivariate Cox survival analysis, higher STS score (hazard ratio [HR] 1.06), higher Zva (HR 1.13), and worse LV-GLS (HR 1.07) were independently associated with long-term survival (all p <0.01). When Zva and LV-GLS were sequentially added to STS score, the c-statistic improved from 0.63 [0.55 to 0.77] to 0.70 [0.60 to 0.81] and 0.78 [0.69 to 0.83], respectively, all p <0.001). Findings were confirmed in the validation subgroup. In conclusion, in patients with severe aortic stenosis and preserved LVEF treated with surgical AVR, baseline Zva and LV-GLS provide improved risk stratification with synergistic prognostic value.

Outcome and undertreatment of mitral regurgitation: a community cohort study

BACKGROUND

Mitral regurgitation is the most common valve disease worldwide but whether the community-wide prevalence, poor patient outcomes, and low rates of surgical treatment justify costly development of new therapeutic interventions remains uncertain. Therefore, we did an observational cohort study to assess the clinical characteristics, outcomes, and degree of undertreatment of mitral regurgitation in a community setting.

METHODS

We used data from Mayo Clinic electronic health records and the Rochester Epidemiology Project to identify all cases of moderate or severe isolated single-valvular mitral regurgitation (with no other severe left-sided valvular disease or previous mitral surgery) diagnosed during a 10-year period in the community setting in Olmsted County (MN, USA). We assessed clinical characteristics, mortality, heart failure incidence, and results of cardiac surgery post-diagnosis.

FINDINGS

Between Jan 1, 2000, and Dec 31, 2010, 1294 community residents (median age at diagnosis 77 years [IQR 66-84]) were diagnosed with moderate or severe mitral regurgitation by Doppler echocardiography (prevalence 0·46% [95% CI 0·42-0·49] overall; 0·59% [0·54-0·64] in adults). Left-ventricular ejection fraction below 50% was frequent (recorded in 538 [42%] patients), and these patients had a slightly lower regurgitant volume than those with an ejection fraction of 50% or higher (mean 39 mL [SD 16] vs 45 mL [21], p<0·0001). Post-diagnosis mortality was mainly cardiovascular in nature (in 420 [51%] of 824 patients for whom the cause of death was available) and higher than expected for residents of the county for age or sex (risk ratio [RR] 2·23 [95% CI 2·06-2·41], p<0·0001). This excess mortality affected all subsets of patients, whether they had a left-ventricular ejection fraction lower than 50% (RR 3·17 [95% CI 2·84-3·53], p<0·0001) or of 50% or higher (1·71 [1·53 -1·91], p<0·0001) and with primary mitral regurgitation (RR 1·73 [95% CI 1·53-1·96], p<0·0001) or secondary mitral regurgitation (2·72 [2·48-3·01], p<0·0001). Even patients with a low comorbidity burden combined with favourable characteristics such as left-ventricular ejection fraction of 50% or higher (RR 1·28 [95% CI 1·10-1·50], p<0·0017) or primary mitral regurgitation (1·29 [1·09-1·52], p=0·0030) incurred excess mortality. Heart failure was frequent (mean 64% [SE 1] at 5 years postdiagnosis), even in patients with left-ventricular ejection fraction of 50% or higher (49% [2] at 5 years postdiagnosis) or in those with primary mitral regurgitation (48% [2]). Mitral surgery was ultimately done in only 198 (15%) of 1294 patients, of which the predominant type of surgery was valve repair (in 149 [75%] patients). Mitral surgery was done in 28 (5%) of 538 patients with left-ventricular ejection fraction below 50% and in 170 (22%) of 756 patients with ejection fraction of 50% or higher, and in 34 (5%) of 723 with secondary mitral regurgitation versus 164 (29%) of 571 with primary regurgitation. All other types of cardiac surgery combined were performed in only 3% more patients (237 [18%] patients) than the number who underwent mitral surgery.

INTERPRETATION

In the community, isolated mitral regurgitation is common and is associated with excess mortality and frequent heart failure postdiagnosis in all patient subsets, even in those with normal left-ventricular ejection fraction and low comorbidity. Despite these poor outcomes, only a minority of affected patients undergo mitral (or any type of cardiac) surgery even in a community with all means of diagnosis and treatment readily available and accessible. This suggests that in a wider population there might be a substantial unmet need for treatment for this disorder.

FUNDING

Mayo Clinic Foundation.

Quantifying the Shift Toward Transcatheter Aortic Valve Replacement in Low-Risk Patients: A Meta-Analysis

BACKGROUND

In recent years, use of transcatheter aortic valve replacement has expanded to include patients at intermediate- and low-risk cohorts. We sought to determine disease prevalence and treatment distribution including transcatheter aortic valve replacement eligibility in low-risk patients across 37 advanced economies.

METHODS AND RESULTS

Four systematic searches were conducted across MEDLINE, EMBASE, and the Cochrane database for studies evaluating disease prevalence, severity, decision making, and survival in patients with aortic stenosis. Estimates of disease prevalence and treatment eligibility were calculated using stochastic simulation and population data for the 37 countries comprising the International Monetary Fund's advanced economies index. Fifty-six studies comprising 42 965 patients were included across 5 domains: prevalence, severity, symptom status, treatment modality, and outcome. The pooled prevalence in the general population aged 60 to 74 years and >75 years was 2.8% (95% confidence interval [CI], 1.4%-4.1%) and 13.1% (95% CI, 8.2%-17.9%), respectively-corresponding to an estimated 16.1 million (95% CI, 12.2-20.3) people in 37 advanced economies. Of these, an estimated 3.2 million (95% CI, 2.2-4.4) patients have severe aortic stenosis with 1.9 million (95% CI, 1.3-2.6) eligible for surgical aortic valve replacement. There are ≈485 230 (95% CI, 284 550-66 7350) high-risk/inoperable patients, 152 690 (95% CI, 73 410-263 000) intermediate-risk patients, and 378 890 (95% CI, 205 130-610 210) low-risk patients eligible for transcatheter aortic valve replacement.

CONCLUSIONS

With a prevalence of 4.5%, an estimated 16.1 million people aged ≥60 years across 37 advanced economies have aortic stenosis. Of these, there are ≈1.9 million patients eligible for surgical aortic valve replacement and 1.0 million patients eligible for transcatheter aortic valve replacement.

Clinical features and prognosis of patients with isolated severe aortic stenosis and valve area less than 1.0 cm2

OBJECTIVE

Current guidelines define severe aortic stenosis (AS) as an aortic valve area (AVA)≤1.0 cm², but some authors have suggested that the AVA cut-off be decreased to 0.8 cm². The aim of this study was, therefore, to better describe the clinical features and prognosis of patients with an AVA of 0.8-0.99 cm².

METHODS

Patients with isolated, severe AS and ejection fraction ≥55% with an AVA of 0.8-0.99 cm² (n=105) were compared with those with an AVA<0.8 cm² (n=155) and 1.0-1.3 cm² (n=81). The endpoint of this study was a combination of death from any cause or aortic valve replacement at or before 3 years.

RESULTS

Patients with an AVA of 0.8-0.99 cm² group comprised predominantly normal-flow, low-gradient (NFLG) AS, while high gradients and low flow were more often observed with an AVA<0.8 cm². The frequency of symptoms was not significantly different between an AVA of 0.8-0.99 cm² and 1.0-1.3 cm². The combined endpoint was achieved in 71%, 52% and 21% of patients with an AVA of 0.8 cm², 0.8-0.99 cm²and 1.0-1.3 cm², respectively (p<0.001). Among patients with an AVA of 0.8-0.99 cm², NFLG AS was associated with a lower hazard (HR=0.40, 95% CI 0.23 to 0.68, p=0.001) of achieving the combined endpoint with outcomes similar to moderate AS in the first 1.5 years of follow-up. Patients with high-gradient or low-flow AS with an AVA of 0.8-0.99 cm² had outcomes similar to those with an AVA<0.8 cm². The sensitivity for the combined endpoint was 61% for an AVA cut-off of 0.8 cm² and 91% for a cut-off of 1.0 cm².

CONCLUSIONS

The outcomes of patients with AS with an AVA of 0.8-0.99 cm² are variable and are more precisely defined by flow-gradient status. Our findings support the current AVA cut-off of 1.0 cm².

Late Outcomes of Transcatheter Aortic Valve Replacement in High-Risk Patients: The FRANCE-2 Registry

BACKGROUND

Transcatheter aortic valve replacement (TAVR) has revolutionized management of high-risk patients with severe aortic stenosis. However, survival and the incidence of severe complications have been assessed in relatively small populations and/or with limited follow-up.

OBJECTIVES

This report details late clinical outcome and its determinants in the FRANCE-2 (FRench Aortic National CoreValve and Edwards) registry.

METHODS

The FRANCE-2 registry prospectively included all TAVRs performed in France. Follow-up was scheduled at 30 days, at 6 months, and annually from 1 to 5 years. Standardized VARC (Valve Academic Research Consortium) outcome definitions were used.

RESULTS

A total of 4,201 patients were enrolled between January 2010 and January 2012 in 34 centers. Approaches were transarterial (transfemoral 73%, transapical 18%, subclavian 6%, and transaortic or transcarotid 3%) or, in 18% of patients, transapical. Median follow-up was 3.8 years. Vital status was available for 97.2% of patients at 3 years. The 3-year all-cause mortality was 42.0% and cardiovascular mortality was 17.5%. In a multivariate model, predictors of 3-year all-cause mortality were male sex (p < 0.001), low body mass index, (p < 0.001), atrial fibrillation (p < 0.001), dialysis (p < 0.001), New York Heart Association functional class III or IV (p < 0.001), higher logistic EuroSCORE (p < 0.001), transapical or subclavian approach (p < 0.001 for both vs. transfemoral approach), need for permanent pacemaker implantation (p = 0.02), and post-implant periprosthetic aortic regurgitation grade ≥2 of 4 (p < 0.001). Severe events according to VARC criteria occurred mainly during the first month and subsequently in <2% of patients/year. Mean gradient, valve area, and residual aortic regurgitation were stable during follow-up.

CONCLUSIONS

The FRANCE-2 registry represents the largest database available on late results of TAVR. Late mortality is largely related to noncardiac causes. Incidence rates of severe events are low after the first month. Valve performance remains stable over time.

Pathophysiology of Aortic Valve Stenosis: Is It Both Fibrocalcific and Sex Specific?

Our understanding of the fundamental biology and identification of efficacious therapeutic targets in aortic valve stenosis has lagged far behind the fields of atherosclerosis and heart failure. In this review, we highlight the most clinically relevant problems facing men and women with fibrocalcific aortic valve stenosis, discuss the fundamental biology underlying valve calcification and fibrosis, and identify key molecular points of intersection with sex hormone signaling.

Rationale and design of the Transcatheter Aortic Valve Replacement to UNload the Left ventricle in patients with ADvanced heart failure (TAVR UNLOAD) trial

BACKGROUND

Coexistence of moderate aortic stenosis (AS) in patients with heart failure (HF) with reduced ejection fraction is not uncommon. Moderate AS increases afterload, whereas pharmacologic reduction of afterload is a pillar of contemporary HF management.

HYPOTHESIS

Unloading the left ventricle by reducing the transaortic gradient with transfemoral transcatheter aortic valve replacement (TAVR) may improve clinical outcomes in patients with moderate AS and HF with reduced ejection fraction.

STUDY DESIGN

The TAVR UNLOAD (NCT02661451) is an international, multicenter, randomized, open-label, clinical trial comparing the efficacy and safety of TAVR with the Edwards SAPIEN 3 Transcatheter Heart Valve in addition to optimal heart failure therapy (OHFT) vs OHFT alone in patients with moderate AS (defined by a mean transaortic gradient ≥20 mm Hg and <40 mm Hg, and an aortic valve area >1.0 cm² and ≤1.5 cm² at rest or after dobutamine stress echocardiography) and reduced ejection fraction. A total of 600 patients will be randomized in a 1:1 fashion. Clinical follow-up is scheduled at 1, 6, and 12 months, and 2 years after randomization. The primary end point is the hierarchical occurrence of all-cause death, disabling stroke, hospitalizations related to HF, symptomatic aortic valve disease or nondisabling stroke, and the change in the Kansas City Cardiomyopathy Questionnaire at 1 year. Secondary end points capture effects on clinical outcome, biomarkers, echocardiographic parameters, and quality of life.

SUMMARY

The TAVR UNLOAD trial aims to test the hypothesis that TAVR on top of OHFT improves clinical outcomes in patients with moderate AS and HF with reduced ejection fraction.

Outcome Implication of Aortic Valve Area Normalized to Body Size in Asymptomatic Aortic Stenosis

Background—

Current guidelines define severe aortic stenosis in patients with aortic valve area normalized to body surface area (AVA/BSA) <0.6 cm 2 /m 2 ; yet, this cutoff has never been validated. Moreover, it is not known whether AVA normalization to other body size indexes allows improved outcome prediction. We aim to test the value of AVA normalized to body size for outcome prediction in asymptomatic aortic stenosis.

Methods and Results—

We included 289 patients with asymptomatic aortic stenosis, preserved ejection fraction, and AVA<1.3 cm 2 at diagnosis. The outcome measure was the occurrence of aortic valve replacement or all-cause death or during follow-up. AVA was normalized to BSA, height, weight, and body mass index. For each normalized index, patients in the lowest tertile were at high risk of events whereas outcome was similar for the other tertiles. High risk of events was observed with AVA/BSA <0.4 cm 2 /m 2 (adjusted hazard ratio [HR], 3.42 [2.09–5.60]), AVA/height <0.45 cm 2 /m (adjusted HR, 3.99 [2.42–6.60]), AVA/weight <0.01 cm 2 /kg (adjusted HR, 3.37 [2.07–5.49]), and AVA/body mass index <0.029 cm 2 /kg per meter square (adjusted HR, 3.23 [1.99–5.24]). Mortality risk was high with AVA/height <0.45 cm 2 /m (adjusted HR, 2.18 [1.28–3.71]), followed by AVA/BSA <0.40 cm 2 /m 2 (adjusted HR, 1.84 [1.09–3.11]), AVA/weight <0.01 cm 2 /kg (adjusted HR, 1.78 [1.07–2.98]), and AVA/body mass index <0.029 cm 2 /kg per meter square (adjusted HR, 1.75 [1.04–2.93]). AVA/height showed better predictive performance than AVA/BSA with improved reclassification and better discrimination (net reclassification improvement: 0.33 versus 0.28; integrated discrimination improvement: 0.10 versus 0.08; C statistic: 0.67 versus 0.65), whereas AVA/weight and AVA/body mass index showed lower predictive capacity.

Conclusions—

Among AVA normalization methods, AVA/height <0.45 cm 2 /m followed by AVA/BSA <0.40 cm 2 /m 2 seem as robust parameters for defining high risk in asymptomatic aortic stenosis. The prognostic value of AVA/height deserves future research.

Low-gradient aortic stenosis

An important proportion of patients with aortic stenosis (AS) have a 'low-gradient' AS, i.e. a small aortic valve area (AVA <1.0 cm(2)) consistent with severe AS but a low mean transvalvular gradient (<40 mmHg) consistent with non-severe AS. The management of this subset of patients is particularly challenging because the AVA-gradient discrepancy raises uncertainty about the actual stenosis severity and thus about the indication for aortic valve replacement (AVR) if the patient has symptoms and/or left ventricular (LV) systolic dysfunction. The most frequent cause of low-gradient (LG) AS is the presence of a low LV outflow state, which may occur with reduced left ventricular ejection fraction (LVEF), i.e. classical low-flow, low-gradient (LF-LG), or preserved LVEF, i.e. paradoxical LF-LG. Furthermore, a substantial proportion of patients with AS may have a normal-flow, low-gradient (NF-LG) AS: i.e. a small AVA-low-gradient combination but with a normal flow. One of the most important clinical challenges in these three categories of patients with LG AS (classical LF-LG, paradoxical LF-LG, and NF-LG) is to differentiate a true-severe AS that generally benefits from AVR vs. a pseudo-severe AS that should be managed conservatively. A low-dose dobutamine stress echocardiography may be used for this purpose in patients with classical LF-LG AS, whereas aortic valve calcium scoring by multi-detector computed tomography is the preferred modality in those with paradoxical LF-LG or NF-LG AS. Although patients with LF-LG severe AS have worse outcomes than those with high-gradient AS following AVR, they nonetheless display an important survival benefit with this intervention. Some studies suggest that transcatheter AVR may be superior to surgical AVR in patients with LF-LG AS.

Meta-analysis of the impact of intervention versus symptom-driven management in asymptomatic severe aortic stenosis

OBJECTIVE

The management of patients with asymptomatic, severe aortic stenosis (AS) is controversial. We performed a meta-analysis to examine the impact on outcomes of aortic valve replacement (AVR) in patients with severe asymptomatic AS versus a symptom-driven intervention approach.

METHODS

A search for studies that examined the outcomes of AVR and management of asymptomatic severe AS was performed. We examined the end points of all-cause mortality, cardiac mortality and sudden cardiac death. Our analysis compared early AVR in asymptomatic patients with a symptom-driven AVR approach (excluding symptomatic patients who did not undergo AVR).

RESULTS

Four observational studies were identified with a total of 1300 patients. There was significant heterogeneity between studies (I²=72%). Using a random-effects model, there was a trend towards reduced overall mortality in patients undergoing early AVR compared with a symptom-driven AVR approach (OR 0.54, 95% CI 0.26 to 1.12, p=0.1). There was no significant reduction in cardiac mortality or sudden death (OR 0.78, p=0.85, and OR 0.34, p=0.25, respectively).

CONCLUSIONS

Although there was a trend towards reduced overall mortality when comparing early AVR in patients with asymptomatic, severe AS to a symptom-driven AVR approach, there was no significant difference in cardiac mortality or sudden death. An individual approach focusing on individual risk stratification and operative mortality is required until more robust, randomised trial data are available.

Temporal Trends in Disease Severity and Predicted Surgical Risk at the Time of Referral for Echocardiography in Patients Diagnosed with Aortic Stenosis

BACKGROUND

Calcific aortic stenosis (AS) is the most common underlying pathology in patients undergoing heart valve surgery, with an expected increasing prevalence among the aging population.

METHODS AND RESULTS

We identified the temporal trends in referral patterns, disease severity, and associated surgical risk among patients with AS between January 1, 1995 and December 31, 2012 at the Duke University Hospital. A total of 6103 patients had a finding of mild (n = 3303), moderate (n = 1648), or severe AS (n = 1152) in a native aortic valve. Overall presence of severe AS increased significantly over time (P = 0.009) with the most substantial increase occurring from 2010 and onward. Median age upon referral (P < 0.001) and attendant predicted surgical risk (P < 0.001) increased significantly in the observation period among patients with a finding of severe AS. Among patients with a finding of severe AS, the proportion of patients aged older than 80 years increased to 51.0% in the most recent time period (2010-2012) compared with 32.6% in the preceding time period (P < 0.001 for overall time trend). Similarly, the proportion of patients with a logistic EuroSCORE greater than 20% increased to 21.3% (2010-2012) from 12.1% (pre-2010).

CONCLUSIONS

Among patients referred for echocardiography to a high-volume tertiary hospital center, a significant increase in the prevalence of severe AS was observed over time. This trend occurred in parallel with increasing age and predicted surgical risk at referral. Health-care resource planning should account for an increasing number of patients in need of high-risk aortic valve replacements in the near future.

Aortic valve area calculation in aortic stenosis by CT and Doppler echocardiography

OBJECTIVES

The aim of this study was to verify the hypothesis that multidetector computed tomography (MDCT) is superior to echocardiography for measuring the left ventricular outflow tract (LVOT) and calculating the aortic valve area (AVA) with regard to hemodynamic correlations and survival outcome prediction after a diagnosis of aortic stenosis (AS).

BACKGROUND

MDCT demonstrated that the LVOT is noncircular, casting doubt on the AVA measurement by 2-dimensional (2D) echocardiography.

METHODS

A total of 269 patients (76 ± 11 years of age, 61% men) with isolated calcific AS (mean gradient 44 ± 18 mm Hg; ejection fraction 58 ± 15%) underwent Doppler echocardiography and MDCT within the same episode of care. AVA was calculated by echocardiography (AVAEcho) and by MDCT (AVACT) using each technique measurement of LVOT area. In the subset of patients undergoing dynamic 4-dimensional MDCT (n = 135), AVA was calculated with the LVOT measured at 70% and 20% of the R-R interval and measured by planimetry (AVAPlani).

RESULTS

Phasic measurements of the LVOT by MDCT yielded slight differences in eccentricity and size (all p < 0.001) but with excellent AVA correlation (r = 0.92, p < 0.0001) and minimal bias (0.05 cm(2)), whereas the AVAPlani showed poor correlations with all other methods (all r values <0.58). AVACT was larger than AVAEcho (difference 0.12 ± 0.16 cm(2); p < 0.0001) but did not improve outcome prediction. Correlation gradient-AVA was slightly better with AVAEcho than AVACT (r = -0.65 with AVAEcho vs. -0.61 with AVACT; p = 0.01), and discordant gradient-AVA was not reduced. For long-term survival, after multivariable adjustment, AVAEcho or AVACT were independently predictive (hazard ratio [HR]: 1.26, 95% confidence interval [CI]: 1.13 to 1.42; p < 0.0001 or HR: 1.18, 95% CI: 1.09 to 1.29 per 0.10 cm(2) decrease; p < 0.0001) with a similar prognostic value (p ≥ 0.80). Thresholds for excess mortality differed between methods: AVAEcho ≤1.0 cm(2) (HR: 4.67, 95% CI: 2.22 to 10.50; p < 0.0001) versus AVACT ≤1.2 cm(2) (HR: 3.16, 95% CI: 1.64 to 6.43; p = 0.005), with simple translation of spline-curve analysis.

CONCLUSIONS

Head-to-head comparison of MDCT and Doppler echocardiography refutes the hypothesis of MDCT superiority for AVA calculation. AVACT is larger than AVAEcho but does not improve the correlation with transvalvular gradient, the concordance gradient-AVA, or mortality prediction compared with AVAEcho. Larger cut-point values should be used for severe AS if AVACT (<1.2 cm(2)) is measured versus AVAEcho (<1.0 cm(2)).