Factors influencing left ventricular structure and stress-corrected systolic function in men and women with asymptomatic aortic valve stenosis (a SEAS Substudy)

Sex Differences in Aortic Stenosis: From the Pathophysiology to the Intervention, Current Challenges, and Future Perspectives

Calcific aortic stenosis (AS) is a major cause of morbidity and mortality in high-income countries. AS presents sex-specific features impacting pathophysiology, outcomes, and management strategies. In women, AS often manifests with a high valvular fibrotic burden, small valvular annuli, concentric left ventricular (LV) remodeling/hypertrophy, and, frequently, supernormal LV ejection fraction coupled with diastolic dysfunction. Paradoxical low-flow low-gradient AS epitomizes these traits, posing significant challenges post-aortic valve replacement due to limited positive remodeling and significant risk of patient-prosthesis mismatch. Conversely, men present more commonly with LV dilatation and dysfunction, indicating the phenotype of classical low-flow low-gradient AS, i.e., with decreased LV ejection fraction. However, these distinctions have not been fully incorporated into guidelines for AS management. The only treatment for AS is aortic valve replacement; women are frequently referred late, leading to increased heart damage caused by AS. Therefore, it is important to reassess surgical planning and timing to minimize irreversible cardiac damage in women. The integrity and the consideration of sex differences in the management of AS is critical. Further research, including sufficient representation of women, is needed to investigate these differences and to develop individualized, sex-specific management strategies.

Hearts apart: sex differences in cardiac remodeling in health and disease

Biological sex is an important modifier of physiology and influences pathobiology in many diseases. While heart disease is the number one cause of death worldwide in both men and women, sex differences exist at the organ and cellular scales, affecting clinical presentation, diagnosis, and treatment. In this Review, we highlight baseline sex differences in cardiac structure, function, and cellular signaling and discuss the contribution of sex hormones and chromosomes to these characteristics. The heart is a remarkably plastic organ and rapidly responds to physiological and pathological cues by modifying form and function. The nature and extent of cardiac remodeling in response to these stimuli are often dependent on biological sex. We discuss organ- and molecular-level sex differences in adaptive physiological remodeling and pathological cardiac remodeling from pressure and volume overload, ischemia, and genetic heart disease. Finally, we offer a perspective on key future directions for research into cardiac sex differences.

Prediction of symptom development and aortic valve replacement in patients with low-gradient severe aortic stenosis

Aims

Current evidence on the prognostic value of exercise stress echocardiography (ESE) in asymptomatic patients with low-gradient severe aortic stenosis (AS) is limited. Therefore, this study aimed to elucidate its prognostic implications for patients with low-gradient severe AS and determine the added value of ESE in risk stratification for this population.

Methods and results

This retrospective observational study included 122 consecutive asymptomatic patients with either moderate [mean pressure gradient (MPG) < 40 mmHg and aortic valve area (AVA) 1.0-1.5 cm2] or low-gradient severe (MPG < 40 mmHg and AVA < 1.0 cm2) AS and preserved left ventricular ejection fraction (≥50%) who underwent ESE. All patients were followed up for AS-related events. Of 143 patients, 21 who met any exclusion criteria, including early interventions, were excluded, and 122 conservatively managed patients [76.5 (71.0-80.3) years; 48.3% male] were included in this study. During a median follow-up period of 989 (578-1571) days, 64 patients experienced AS-related events. Patients with low-gradient severe AS had significantly lower event-free survival rates than those with moderate AS (log-rank test, P < 0.001). Multivariable Cox regression analysis showed that the mitral E/e' ratio during exercise was independently associated with AS-related events (hazard ratio = 1.075, P < 0.001) in patients with low-gradient severe AS.

Conclusion

This study suggests that asymptomatic patients with low-gradient severe AS have worse prognoses than those with moderate AS. Additionally, the mitral E/e' ratio during exercise is a useful parameter for risk stratification in patients with low-gradient severe AS.

Effect of Sex and Flow Status on Outcomes After Surgical or Transcatheter Aortic Valve Replacement

Background

Low stroke volume index <35 ml/m2 despite preserved ejection fraction (paradoxical low flow [PLF]) is associated with adverse outcomes in patients with aortic stenosis undergoing transcatheter aortic valve replacement (TAVR) or surgical aortic valve replacement (SAVR). However, whether the risk associated with PLF is similar in both sexes is unknown.

Objectives

The purpose of this study was to analyze the risk associated with PLF in severe aortic stenosis for men and women randomized to TAVR or SAVR.

Methods

Patients with ejection fraction ≥50% from the PARTNER (Placement of Aortic Transcatheter Valves) 2 and 3 trials were stratified by sex and treatment arm. The impact of PLF on the 2-year occurrence of the composite of death or heart failure hospitalization (primary endpoint) and of all-cause mortality alone (secondary endpoint) was analyzed. Analysis of variance was used to assess baseline differences between groups. Multivariate Cox regression analysis was used to identify predictors of the endpoint.

Results

Out of 2,242 patients, PLF was present in 390 men and 239 women (30% vs 26%, P = 0.06). PLF was associated with a higher rate of NYHA functional class III to IV dyspnea (60% vs 54%, P < 0.001) and a higher prevalence of atrial fibrillation (39% vs 24%, P < 0.001). PLF was a significant predictor of the primary endpoint among women undergoing SAVR in multivariate analysis (adjusted HR: 2.25 [95% CI: 1.14-4.43], P = 0.02) but was not associated with a worse outcome in any of the other groups (all P > 0.05).

Conclusions

In women with PLF, TAVR may improve outcomes compared to SAVR. PLF appears to have less impact on outcomes in men.

Multimodality Imaging to Explore Sex Differences in Aortic Stenosis

The aim of this article is to review sex differences in aortic stenosis (AS) assessed with multimodality imaging. Echocardiography remains the mainstay imaging technique to diagnose AS and provides important insights into the differences between men and women in relation to valve haemodynamic and left-ventricular response. However, echocardiography does not have adequate resolution to provide important insights into sex differences in the degenerative, calcific pathophysiological process of the aortic valve. CT shows that women with AS have more fibrotic changes of the aortic valve whereas men show more calcific deposits. Cardiac magnetic resonance shows that women have left ventricles that are less hypertrophic and smaller compared with those of men, while men have more replacement myocardial fibrosis. These differences may lead to different responses to aortic valve replacement because myocardial diffuse fibrosis but not replacement myocardial fibrosis may regress after the procedure. Sex differences in the pathophysiological process of AS can be assessed using multimodality imaging, assisting in decisionmaking in these patients.

Grading of Aortic Stenosis: Is it More Complicated in Women?

Aortic stenosis (AS) is the most common valvular heart disease and the main indication for valvular replacement in older women. Correct AS grading is mandatory for an adequate selection of patients for both surgical and transcatheter aortic valve replacement. Women and men have different AS severity grades at the same level of aortic valve calcification. Moreover, besides having smaller cardiac volumes, left ventricular outflow tract and aortic size, women have a specific pattern of left ventricular structural and functional remodelling in response to the AS-related chronic pressure overload. Here, the sex-specific cardiac changes in AS that make AS grading more challenging in women, with consequences for the management and outcome of this group of patients, are reviewed.

Sex differences in aortic stenosis: Identification of knowledge gaps for sex-specific personalized medicine

Objectives

This review summarizes sex-based differences in aortic stenosis (AS) and identifies knowledge gaps that should be addressed by future studies.

Background

AS is the most common valvular heart disease in developed countries. Sex-specific differences have not been fully appreciated, as a result of widespread under diagnosis of AS in women.

Summary

Studies including sex-stratified analyses have shown differences in pathophysiology with less calcification and more fibrosis in women's aortic valve. Women have impaired myocardial perfusion reserve and different compensatory response of the left ventricle (LV) to pressure overload, with concentric remodeling and more diffuse fibrosis, in contrast to men with more focal fibrosis and more dilated/eccentrically remodeled LV. There is sex difference in clinical presentation and anatomical characteristics, with women having more paradoxical low-flow/low-gradient AS, under-diagnosis and severity underestimated, with less referral to aortic valve replacement (AVR) compared to men. The response to therapies is also different: women have more adverse events with surgical AVR and greater survival benefit with transcatheter AVR. After AVR, women would have more favorable LV remodeling, but sex-related differences in changes in myocardial reserve flow need future research.

Conclusions

Investigation into these described sex-related differences in AS offers potential utility for improving prevention and treatment of AS in women and men. To better understand sex-based differences in pathophysiology, clinical presentation, and response to therapies, sex-specific critical knowledge gaps should be addressed in future research for sex-specific personalized medicine.

Tgfβ1-Cthrc1 Signaling Plays an Important Role in the Short-Term Reparative Response to Heart Valve Endothelial Injury

OBJECTIVE

Aortic valve disease is a common worldwide health burden with limited treatment options. Studies have shown that the valve endothelium is critical for structure-function relationships, and disease is associated with its dysfunction, damage, or injury. Therefore, therapeutic targets to maintain a healthy endothelium or repair damaged endothelial cells could hold promise. In this current study, we utilize a surgical mouse model of heart valve endothelial cell injury to study the short-term response at molecular and cellular levels. The goal is to determine if the native heart valve exhibits a reparative response to injury and identify the mechanisms underlying this process. Approach and Results: Mild aortic valve endothelial injury and abrogated function was evoked by inserting a guidewire down the carotid artery of young (3 months) and aging (16-18 months) wild-type mice. Short-term cellular responses were examined at 6 hours, 48 hours, and 4 weeks following injury, whereas molecular profiles were determined after 48 hours by RNA-sequencing. Within 48 hours following endothelial injury, young wild-type mice restore endothelial barrier function in association with increased cell proliferation, and upregulation of transforming growth factor beta 1 (Tgfβ1) and the glycoprotein, collagen triple helix repeat containing 1 (Cthrc1). Interestingly, this beneficial response to injury was not observed in aging mice with known underlying endothelial dysfunction.

CONCLUSIONS

Data from this study suggests that the healthy valve has the capacity to respond to mild endothelial injury, which in short term has beneficial effects on restoring endothelial barrier function through acute activation of the Tgfβ1-Cthrc1 signaling axis and cell proliferation.

Matters of the heart: Cellular sex differences

Nearly all cardiovascular diseases show sexual dimorphisms in prevalence, presentation, and outcomes. Until recently, most clinical trials were carried out in males, and many animal studies either failed to identify the sex of the animals or combined data obtained from males and females. Cellular sex in the heart is relatively understudied and many studies fail to report the sex of the cells used for in vitro experiments. Moreover, in the small number of studies in which sex is reported, most of those studies use male cells. The observation that cells from males and females are inherently different is becoming increasingly clear - either due to acquired differences from hormones and other factors or due to intrinsic differences in genotype (XX or XY). Because of the likely contribution of cellular sex differences in cardiac health and disease, here, we explore differences in mammalian male and female cells in the heart, including the less-studied non-myocyte cell populations. We discuss how the heart's microenvironment impacts male and female cellular phenotypes and vice versa, including how secretory profiles are dependent on cellular sex, and how hormones contribute to sexually dimorphic phenotypes and cellular functions. Intracellular mechanisms that contribute to sex differences, including gene expression and epigenetic remodeling, are also described. Recent single-cell sequencing studies have revealed unexpected sex differences in the composition of cell types in the heart which we discuss. Finally, future recommendations for considering cellular sex differences in the design of bioengineered in vitro disease models of the heart are provided.

One-year impact of bariatric surgery on left ventricular mechanics: results from the prospective FatWest study

Aims

Patients with severe obesity are predisposed to left ventricular (LV) hypertrophy, increased myocardial oxygen demand, and impaired myocardial mechanics. Bariatric surgery leads to rapid weight loss and improves cardiovascular risk profile. The present prospective study assesses whether LV wall mechanics improve 1 year after bariatric surgery.

Methods and results

Ninety-four severely obese patients [43 ± 10 years, 71% women, body mass index (BMI) 41.8 ± 4.9 kg/m², 57% with hypertension] underwent echocardiography before, 6 months and 1 year after gastric bypass surgery in the FatWest (Bariatric Surgery on the West Coast of Norway) study. We assessed LV mechanics by midwall shortening (MWS) and global longitudinal strain (GLS), LV power/mass as 0.222 × cardiac output × mean blood pressure (BP)/LV mass, and myocardial oxygen demand as the LV mass-wall stress-heart rate product. Surgery induced a significant reduction in BMI, heart rate, and BP (P < 0.001). Prevalence of LV hypertrophy fell from 35% to 19% 1 year after surgery (P < 0.001). The absolute value of GLS improved by—4.6% (i.e. 29% increase in GLS) while LV ejection fraction, MWS, and LV power/mass remained unchanged. In multivariate regression analyses, 1 year improvement in GLS was predicted by lower preoperative GLS, larger mean BP, and BMI reduction (all P < 0.05). Low 1-year MWS was associated with female sex, preoperative hypertension, and higher 1-year LV relative wall thickness and myocardial oxygen demand (all P < 0.001).

Conclusion

In severely obese patients, LV longitudinal function is largely recovered one year after bariatric surgery due to reduced afterload. LV midwall mechanics does not improve, particularly in women and patients with persistent LV geometric abnormalities.

ClinicalTrials.gov identifier

NCT01533142, 15 February 2012.

Effect of Transaortic Valve Intervention for Aortic Stenosis on Myocardial Mechanics

Chronic afterload excess in aortic stenosis results in compensatory concentric hypertrophy which mitigates the increased systolic load. Surgical aortic valve replacement has been shown to decrease afterload and improve left ventricular (LV) ejection fraction (EF). The extent to which these changes take place in patients undergoing TAVI (transcatheter aortic valve intervention) may be different than what has been observed in the surgical aortic valve replacement patients who were generally younger with few co-morbidities. Accordingly, we analyzed indices of LV structure and ventricular mechanics pre- and 1-year after TAVI in 397 patients (mean age 81±9, 46% women) with severe symptomatic aortic stenosis, complete echocardiographic data was available in 156 patients and these patients compromised our study population. Our principal findings are: (1) LV remodeling occurs after TAVI; (2) afterload decreases significantly; (3) LV chamber and myocardial function, assessed by left ventricular ejection fraction and midwall fractional shortening, and stroke volume, respectively, remain unchanged or decrease. In conclusion, TAVI effects LV remodeling despite significant co-morbidities. Thus, TAVI reduces afterload and leads to LV remodeling. Surprisingly, however, systolic function does not improve. These data run counter to the paradigm that afterload reduction improves systolic function and suggest that the response to afterload reduction is complex in the TAVI population.

Prognostic impact of impaired left ventricular midwall function during progression of aortic stenosis

OBJECTIVE

In hypertension, indexes of midwall left ventricular (LV) function may identify patients at higher cardiovascular (CV) risk independent of normal LV ejection fraction (EF). We analyzed the association of baseline and new-onset LV midwall dysfunction with CV outcome in a large population of patients with asymptomatic aortic stenosis (AS).

METHODS

One thousand four hundred seventy-eight patients with asymptomatic AS and normal EF (≥50%) at baseline in the Simvastatin Ezetimibe in Aortic Stenosis (SEAS) study were followed for a median of 4.3 years. LV systolic function was assessed by biplane EF and midwall shortening (MWS, low if <14% in men/16% in women) at baseline and annual echocardiographic examinations.

RESULTS

One hundred twenty-three CV deaths and heart failure hospitalizations occurred during follow-up. In Cox analyses, adjusting for age, gender, body mass index, hypertension, EF, AS severity, LV hypertrophy and systemic arterial compliance, low baseline MWS predicted 61% higher risk of a major CV event and a twofold higher risk of death and heart failure hospitalization (P < .05). New-onset low MWS developed in 574 patients, particularly in elderly women with higher blood pressure and more severe AS (P < .05). In time-varying Cox analysis, new-onset low MWS was associated with a twofold higher risk of CV death and heart failure hospitalization, independent of changes over time in EF, AS severity, LV hypertrophy and systemic arterial compliance (P < .05).

CONCLUSIONS

Low MWS develops in a large proportion of patients with AS and normal EF during valve disease progression and is a marker of increased CV risk.

Sex-Related Differences in the Extent of Myocardial Fibrosis in Patients With Aortic Valve Stenosis

OBJECTIVES

The aim of this study was to assess the effect of sex on myocardial fibrosis as assessed by using cardiac magnetic resonance (CMR) imaging in aortic stenosis (AS).

BACKGROUND

Previous studies reported sex-related differences in the left ventricular (LV) remodeling response to pressure overload in AS. However, there are very few data regarding the effect of sex on myocardial fibrosis, a key marker of LV decompensation and adverse cardiac events in AS.

METHODS

A total of 249 patients (mean age 66 ± 13 years; 30% women) with at least mild AS were recruited from 2 prospective observational cohort studies and underwent comprehensive Doppler echocardiography and CMR examinations. On CMR, T1 mapping was used to quantify extracellular volume (ECV) fraction as a marker of diffuse fibrosis, and late gadolinium enhancement (LGE) was used to assess focal fibrosis.

RESULTS

There was no difference in age between women and men (age 66 ± 15 years vs 66 ± 12 years; p = 0.78). However, women presented with a better cardiovascular risk profile than men with less hypertension, dyslipidemia, diabetes, and coronary artery disease (all, p ≤ 0.10). As expected, LV mass index measured by CMR imaging was smaller in women than in men (p < 0.0001). Despite fewer comorbidities, women presented with larger ECV fraction (median: 29.0% [25th to 75th percentiles: 27.4% to 30.6%] vs. 26.8% [25th to 75th percentiles: 25.1% to 28.7%]; p < 0.0001) and similar LGE (median: 4.5% [25th-75th percentiles: 2.3% to 7.0%] vs. 2.8% [25th-75th percentiles: 0.6% to 6.8%]; p = 0.20) than men. In multivariable analysis, female sex remained an independent determinant of higher ECV fraction and LGE (all, p ≤ 0.05).

CONCLUSIONS

Women have greater diffuse and focal myocardial fibrosis independent of the degree of AS severity. These findings further emphasize the sex-related differences in LV remodeling response to pressure overload.

Transcriptional sex and regional differences in paired human atrial and ventricular cardiac biopsies collected in vivo

Transcriptional studies of the human heart provide insight into physiological and pathophysiological mechanisms, essential for understanding the fundamental mechanisms of normal cardiac function and how they are altered by disease. To improve the understanding of why men and women may respond differently to the same therapeutic treatment it is crucial to learn more about sex-specific transcriptional differences. In this study the transcriptome of right atrium and left ventricle was compared across sex and regional location. Paired biopsies from five male and five female patients undergoing aortic valve replacement or coronary artery bypass grafting were included. Gene expression analysis identified 620 differentially expressed transcripts in atrial and ventricular tissue in men and 471 differentially expressed transcripts in women. In total 339 of these transcripts overlapped across sex but notably, 281 were unique in the male tissue and 162 in the female tissue, displaying marked sex differences in the transcriptional machinery. The transcriptional activity was significantly higher in atrias than in ventricles as 70% of the differentially expressed genes were upregulated in the atrial tissue. Furthermore, pathway- and functional annotation analyses performed on the differentially expressed genes showed enrichment for a more heterogeneous composition of biological processes in atrial compared with the ventricular tissue, and a dominance of differentially expressed genes associated with infection disease was observed. The results reported here provide increased insights about transcriptional differences between the cardiac atrium and ventricle but also reveal transcriptional differences in the human heart that can be attributed to sex.

Impact of estimated left atrial volume on prognosis in patients with asymptomatic mild to moderate aortic valve stenosis

BACKGROUND

The prognostic impact of increased left atrial (LA) volume in mild-to-moderate aortic valve stenosis (AS) is unclear. We investigated the association of estimated LA volume with prognosis in a large prospective study of patients with asymptomatic mild-to-moderate AS.

METHODS

The association of estimated LA volume with major cardiovascular events (MACE, combined cardiovascular death, heart failure hospitalization and non-hemorrhagic stroke) was assessed in 1534 patients with initially mild-to moderate asymptomatic AS, participating in the Simvastatin Ezetimibe in Aortic Stenosis study for a median of 4.3 years. LA volume was estimated from LA diameter applying a validated nonlinear equation and indexed to body height in meters squared (eLAVI). An enlarged eLAVI was identified by using sex-specific cut-offs (>19 ml/height² in men and >17 ml/height² in women).

RESULTS

Patients with enlarged eLAVI were older, more obese, and had higher systolic blood pressure and left ventricular (LV) mass index (all p < 0.001). During follow-up, incident MACE occurred in 137 patients, more often in patients with enlarged eLAVI (20% vs. 7.7%, p < 0.001). Using aortic valve replacement as a competing risk event, enlarged eLAVI at baseline predicted increased hazard rate (HR) of MACE (HR 2.21 [95% confidence interval 1.37-3.55], p = 0.001) independent of significant associations with presence of LV hypertrophy, older age, higher peak aortic jet velocity, serum creatinine and lower LV ejection fraction and stroke volume.

CONCLUSIONS

Presence of enlarged eLAVI was independently associated with increased risk of MACE in patients with mild-to moderate asymptomatic AS.

An Asian Perspective on Gender Differences in Clinical Outcomes and Echocardiographic Profiles of Patients With Medically Managed Severe Aortic Stenosis

BACKGROUND

Gender differences in valvular heart disease are increasingly recognised. A prior study has suggested better surgical outcomes in women with symptomatic aortic stenosis (AS). We investigate gender differences in medically managed severe AS.

METHOD

We studied 347 patients with severe AS (aortic valve area index <0.6 cm²/m²) in terms of baseline clinical background, echocardiographic characteristics, and clinical outcomes. Appropriate univariate and multivariate models were employed, while Kaplan-Meier curves were constructed to compare mortality outcomes.

RESULTS

In total, 205 (59%) patients were women. Despite higher incidences of hypertension (75.6% vs 47.3%) and diabetes mellitus (46.5% vs 29.5%) in women, women had improved survival (Kaplan-Meier log-rank = 6.24, p = 0.012). After adjusting for age (hazard ratio [HR], 1.034; 95% confidence interval [CI], 1.014-1.054), hypertension (HR, 1.469; 95% CI, 0.807-2.673), diabetes (HR, 1.219; 95% CI, 0.693-2.145), and indexed aortic valve area (HR 0.145, 95% CI 0.031-0.684) on multivariate analyses, female gender remained independently associated with lower mortality (HR, 0.561; 95%, CI 0.332-0.947). Women tended to have smaller body surface area (BSA), left ventricular (LV) internal diastolic diameter, and smaller LV outflow tract diameter but were similar to men in terms of LV ejection fraction, AS severity, and patterns of LV remodelling.

CONCLUSIONS

Women appeared to have better outcomes compared to men in medically managed severe AS. These gender differences warrant further study and may affect prognosis, follow-up, and timing of valve surgery.

Effects of Aortic Valve Replacement on Left Ventricular Diastolic Function in Patients With Aortic Valve Stenosis

The afterload increase imposed by severe aortic valve stenosis (AS) creates concentric left ventricular (LV) remodeling and diastolic dysfunction (DD), which are both markers of poor clinical outcome. Ideally, a correctly timed surgery for isolated AS can reverse the LV remodeling. However, data on LV DD after aortic valve replacement (AVR) are sparse and contrasting. Aims of the study are to define the markers of a favorable evolution of the DD at follow-up. Patients with severe isolated AS, scheduled for AVR were prospectively enrolled. Transthoracic echocardiography with DD assessment was performed before surgery, and at 12 months after surgery. Global LV longitudinal and circumferential strain, peak atrial longitudinal and contraction strain (PALS, PACS) were obtained at baseline. LV septal biopsy to assess fibrosis was performed at the time of AVR. Sixty-seven patients were enrolled, age 72 ± 8 years, 66% female, ejection fraction 61 ± 8%, E/e' 13 ± 6, PALS 23 ± 7%. Normal estimated left atrial pressure was detected in 19/67 (28%) versus 43/67 (64%) at follow-up (p <0.0001). In the 37 patients with biopsy available, fibrosis was 24 ± 12%. PALS and AS severity were correlated with LV fibrosis (R² = 0.19; p = 0.006, and R² = 0.15; p = 0.02, respectively). PALS (odds ratio: 1.19 [1.05 to 1.41], p = 0.02) and PACS (odds ratio: 1.24 [1.06 to 1.50], p = 0.006) were the only baseline noninvasive parameters independently associated with normal left atrial pressure at follow-up. Mean follow-up time was 791 ± 245 days, and 8 (12%) patients had cardiovascular events (death, hospital admission due to heart failure or ischemic disease, and onset of atrial fibrillation). Myocardial fibrosis (p = 0.05), baseline PALS (p = 0.004), and PACS (p = 0.03) were associated with cardiovascular events. In conclusion, LV diastolic function generally improves after AVR for severe AS. Baseline PALS, PACS, and LV fibrosis were related to the DD and clinical outcome at follow-up; these parameters might cue a better diastolic response to the afterload correction.

Remodeling classification system considering left ventricular volume in patients with aortic valve stenosis: Association with adverse cardiovascular outcomes

BACKGROUND

To assess prevalence and clinical implications of left ventricular (LV) remodeling considering: LV volume, mass and relative wall thickness at the time of aortic valve stenosis diagnosis.

METHODS AND RESULTS

We retrospectively analyzed 343 patients (age 79.2 ± 9.5 years, 48.1% males) with functional aortic valve area (AVA) ≤ 1.5 cm² . LV geometric patterns and clinical outcomes (combined death, cardiac hospitalization, aortic valve replacement [AVR]) were evaluated. According to the new LV remodeling classification, 4.9% had normal geometry, 7.5% concentric remodeling, 39.3% concentric hypertrophy (LVH), 22.4% mixed LVH, 12.5% dilated LVH, 3.2% eccentric LVH and 4.3% eccentric remodeling, 5.5% had not classifiable LVH. Indexed stroke volume (SVi) was higher in patients with concentric LVH (40.3 ± 11.9 mL/m² ) and mixed LVH (41.6 ± 13.4 mL/m² ) and lower in patients with eccentric LVH (24.9 ± 7.7 mL/m² ), concentric (36.6 ± 12.7 mL/m² ) and eccentric remodeling (34.9 ± 9.5 mL/m² ), P = 0.003. During a median follow-up of 2.2 years, 260 (75.8%) had the combined end point. A significant association between the combined end point and LV dilation (P = 0.010) or LV remodeling patterns (P = 0.0001) was found. After multivariable adjustment for AVR, concentric remodeling (HR 3.12, IC 95% 1.14-8.55; P = 0.02) and dilated LVH (HR 3.48, IC 95% 1.31-9.27; P = 0.01) were strongly associated with death or cardiac hospitalizations.

CONCLUSIONS

In patients with AVA ≤ 1.5 cm² , when the new LV remodeling classification system is applied, only a minority had normal geometry and less than half had "classic" concentric LVH or remodeling. LV volume dilatation is frequent and associated with adverse outcome. Concentric remodeling, eccentric remodeling, dilated LVH had the worst noninvasive hemodynamic profile and prognosis.

Impact of left ventricular remodelling patterns on outcomes in patients with aortic stenosis

Aims

The objective of this study was to examine the association between the different patterns of left ventricular (LV) remodelling/hypertrophy on all-cause and cardiovascular mortality in patients with aortic stenosis (AS).

Methods and results

In total, 747 consecutive patients (69 ± 14 years, 57% men) with AS and preserved LV ejection fraction were included in this study. According to LV mass index and relative wall thickness, patients were classified into four LV patterns: normal, concentric remodelling (CR), concentric hypertrophy (CH), and eccentric hypertrophy (EH). One hundred and sixteen patients (15%) had normal pattern, 66 (9%) had EH, 169 (23%) had CR, and 396 (53%) had CH. During a median follow-up of 6.4 years, 339 patients died (242 from cardiovascular causes). CH was associated with higher risk of all-cause mortality compared with the three other LV patterns (all P < 0.05). After multivariable adjustment, CH remained associated with higher risk of mortality (HR = 1.27, 95% CI 1.01-1.61, P = 0.046). There was a significant interaction (P < 0.05) between sex and CH with regards to the impact on mortality: CH was associated with worse outcome in women (P = 0.0001) but not in men (P = 0.22). In multivariable analysis, CH remained associated with higher risk of worse outcome in women (HR = 1.56, 95% CI 1.08-2.24, P = 0.018).

Conclusions

This study shows that CH was independently associated with increased risk of mortality in AS patients with preserved ejection fraction. This association was observed in women but not in men. The pattern of LV remodelling/hypertrophy should be integrated in the risk stratification process in patients with AS.

Echocardiographic aortic valve calcification and outcomes in women and men with aortic stenosis

Objective

Sex differences in risk factors of aortic valve calcification (AVC) by echocardiography have not been reported from a large prospective study in aortic stenosis (AS).

Methods

AVC was assessed using a prognostically validated visual score and grouped into none/mild or moderate/severe AVC in 1725 men and women with asymptomatic AS in the Simvastatin Ezetimibe in Aortic Stenosis study. The severity of AS was assessed by the energy loss index (ELI) taking pressure recovery in the aortic root into account.

Results

More men than women had moderate/severe AVC at baseline despite less severe AS by ELI (p<0.01). Moderate/severe AVC at baseline was independently associated with lower aortic compliance and more severe AS in both sexes, and with increased high-sensitive C reactive protein (hs-CRP) only in men (all p<0.01). In Cox regression analyses, moderate/severe AVC at baseline was associated with a 2.5-fold (95% CI 1.64 to 3.80) higher hazard rate of major cardiovascular events in women, and a 2.2-fold higher hazard rate in men (95% CI 1.54 to 3.17) (both p<0.001), after adjustment for age, hypertension, study treatment, aortic compliance, left ventricular (LV) mass and systolic function, AS severity and hs-CRP. Moderate/severe AVC at baseline also predicted a 1.8-fold higher hazard rate of all-cause mortality in men (95% CI 1.04 to 3.06, p<0.05) independent of age, AS severity, LV mass and aortic compliance, but not in women.

Conclusion

In conclusion, AVC scored by echocardiography has sex-specific characteristics in AS. Moderate/severe AVC is associated with higher cardiovascular morbidity in both sexes, and with higher all-cause mortality in men.

Trial registration number

ClinicalTrials.gov identifier: NCT00092677

Comparison of Frequency of Ischemic Cardiovascular Events in Patients With Aortic Stenosis With Versus Without Asymmetric Septal Hypertrophy (from the SEAS Trial)

Asymmetric interventricular septum hypertrophy (ASH) has been associated with increased perioperative morbidity and mortality in patients with severe, symptomatic aortic valve stenosis (AS). Less is known about the prognostic impact of ASH during progression of AS. Clinical, echocardiographic, and outcome data from 1,691 patients with initially asymptomatic, mostly moderate AS, participating in the Simvastatin Ezetimibe in Aortic Stenosis (SEAS) study was used. ASH was considered present if interventricular septum/posterior wall thickness ratio in end-diastole ≥1.5. The associations of ASH with hazard rate of ischemic cardiovascular events were tested in time-dependent Cox regression analyses. Based on the presence of ASH at study echocardiograms, the study population was grouped in to a no-ASH, nonpersistent ASH, persistent ASH, and new-onset ASH groups. During a median of 4.3 years of follow-up, ASH persisted or developed in 17% of patients. Persistent or new-onset ASH was characterized by higher left ventricular mass index and ejection fraction at baseline (both p <0.05) but not with female gender or hypertension. In time-varying Cox regression analyses adjusting for these confounders, persistent or new-onset ASH was associated with higher hazard rate of ischemic cardiovascular events (hazard rate 1.45; 95% confidence interval 1.09 to 1.91, p = 0.01), in particular coronary artery bypass grafting (hazard rate 1.69; 95% confidence interval 1.17 to 2.47; p = 0.006), whereas no association with increased mortality was found. In conclusion, in patients with AS without diabetes or known renal or cardiovascular disease participating in the SEAS study, persistent or new-onset ASH during progression of AS was associated with higher rate of ischemic cardiovascular events.

Mechanistic Pathways of Sex Differences in Cardiovascular Disease

Major differences between men and women exist in epidemiology, manifestation, pathophysiology, treatment, and outcome of cardiovascular diseases (CVD), such as coronary artery disease, pressure overload, hypertension, cardiomyopathy, and heart failure. Corresponding sex differences have been studied in a number of animal models, and mechanistic investigations have been undertaken to analyze the observed sex differences. We summarize the biological mechanisms of sex differences in CVD focusing on three main areas, i.e., genetic mechanisms, epigenetic mechanisms, as well as sex hormones and their receptors. We discuss relevant subtypes of sex hormone receptors, as well as genomic and nongenomic, activational and organizational effects of sex hormones. We describe the interaction of sex hormones with intracellular signaling relevant for cardiovascular cells and the cardiovascular system. Sex, sex hormones, and their receptors may affect a number of cellular processes by their synergistic action on multiple targets. We discuss in detail sex differences in organelle function and in biological processes. We conclude that there is a need for a more detailed understanding of sex differences and their underlying mechanisms, which holds the potential to design new drugs that target sex-specific cardiovascular mechanisms and affect phenotypes. The comparison of both sexes may lead to the identification of protective or maladaptive mechanisms in one sex that could serve as a novel therapeutic target in one sex or in both.

Increased hsCRP is associated with higher risk of aortic valve replacement in patients with aortic stenosis

Objective To investigate relations between inflammation and aortic valve stenosis (AS) by measuring high-sensitivity C-reactive protein, at baseline (hsCRP0) and after 1 year (hsCRP1) and exploring associations with aortic valve replacement (AVR). Design We examined 1423 patients from the Simvastatin and Ezetimibe in Aortic Stenosis study. Results During first year of treatment, hsCRP was reduced both in patients later receiving AVR (2.3 [0.9-4.9] to 1.8 [0.8-5.4] mg/l, p < 0.001) and not receiving AVR (1.90 [0.90-4.10] to 1.3 [0.6-2.9] mg/l, p < 0.001). In Cox-regression analyses, hsCRP1 predicted later AVR (HR = 1.17, p < 0.001) independently of hsCRP0 (HR = 0.96, p = 0.33), aortic valve area (AVA) and other risk factors. A higher rate of AVR was observed in the group with high hsCRP0 and an increase during the first year (AVRhighCRP0CRP1inc = 47.3% versus AVRhighCRP0CRP1dec = 27.5%, p < 0.01). The prognostic benefit of a 1-year reduction in hsCRP was larger in patients with high versus low hsCRP0 eliminating the difference in incidence of AVR between high versus low hsCRP0 (AVRhighCRP0CRP1dec = 27.5% versus AVRlowCRP0CRP1dec = 25.8%, p = 0.66) in patients with reduced hsCRP during the first year. Conclusions High hsCRP1 or an increase in hsCRP during the first year of follow-up predicted later AVR independently of AVA, age, gender and other risk factors, although no significant improvement in C-statistics was observed.

Relation of Left Ventricular Mass to Prognosis in Initially Asymptomatic Mild to Moderate Aortic Valve Stenosis

The prognostic importance of left ventricular (LV) mass in nonsevere asymptomatic aortic stenosis has not been documented in a large prospective study.

Echocardiographic determinants of LV functional improvement after transcatheter aortic valve replacement

BACKGROUND

Transcatheter aortic valve replacement (TAVR) is an established therapy in high-risk patients with severe aortic stenosis. Among patients with reduced left ventricular ejection fraction (LVEF), it is unclear which patients will derive maximal benefit from TAVR.

METHODS

Clinical and echocardiographic data of patients with severe aortic stenosis and low LVEF (≤50%) who underwent TAVR at a single institution during 2009-2013 were retrospectively analyzed. Patients were divided into 2 groups post-TAVR based on improved LV function (Group A = ΔLVEF ≥ 10%) versus persistent LV dysfunction (Group B = ΔLVEF<10%). Echocardiographic parameters were assessed for their association with LVEF change post-TAVR. Kaplan-Meier analysis was performed to generate survival estimates.

RESULTS

Of 382 patients who underwent TAVR, 60 patients had low LVEF, LV function failed to improve ≥10% in 50% of patients following the procedure (Group B). At baseline echocardiograms, Group B had higher LVEF, stroke volume (SV), SV index; and lower E, E/E', and estimated pulmonary arterial systolic pressure (PASP) compared to Group A. Higher mortality was found in Group B compared to the Group A (p = 0.003) with a significantly shorter survival (Group A = 3.3 ± 0.1 years vs Group B = 2.7 ± 0.2 years, p = 0.003). One-year event free survival was 53.3% in Group B compared to 93.3% in Group A, with a stable trend over ensuing years (5-year survival; 53.3% versus 90.0%, p = 0.003).

CONCLUSIONS

In patients undergoing TAVR with depressed LV function, those who failed to improve were more likely to have relatively higher LVEF, SV, and SVI; and lower E, E/E', and PASP at baseline. Mortality rates were found to be higher in persistent LV dysfunction group. © 2015 Wiley Periodicals, Inc.

Myocardial function in aortic stenosis--insights from radial multilayer Doppler strain

Background

Left ventricular (LV) radial tissue Doppler imaging (TDI) strain increases gradually from the subepicardial to the subendocardial layer in healthy individuals. A speckle tracking echocardiography study suggested this gradient to be reduced in parallel with increasing aortic stenosis (AS) severity.

Methods

We used TDI strain in 84 patients with AS (mean age 73 ± 10 years, 56% hypertensive) for superior assessment of layer strain. 38 patients had non-severe and 46 severe AS by aortic valve area corrected for pressure recovery. Peak systolic radial TDI strain was measured in the subendocardial, mid-myocardial and subepicardial layers of the basal inferior LV wall, each within a region of interest of 2 × 6 mm (strain length 2 mm).

Results

Radial strain was lower in the subepicardial layer (33.4 ± 38.6%) compared to the mid-myocardial and subendocardial layers (50.3 ± 37.3% and 53.0 ± 40.0%, respectively, both p < 0.001 vs. subepicardial). In the subendo- and midmyocardium, radial strain was lower in patients with severe AS compared to those with non-severe AS (p < 0.05). In multivariate regression analyses including age, heart rate, inferior wall thickness, hypertension, and AS severity, radial strain in the mid-myocardium was primarily attenuated by presence of hypertension (β = −0.23) and AS severity (β = −0.26, both p < 0.05), while radial strain in the subendocardium was significantly influenced by AS severity only (β = −0.35, p < 0.01).

Conclusions

In AS, both the AS severity and concomitant hypertension attenuate radial TDI strain in the inferior LV wall. The subendocardial radial strain is mainly influenced by AS severity, while midmyocardial radial strain is attenuated by both hypertension and AS severity.

Combined circumferential and longitudinal left ventricular systolic dysfunction in patients with asymptomatic aortic stenosis

BACKGROUND

Early detection of left ventricular (LV) systolic dysfunction is pivotal in the management of patients with aortic stenosis (AS). LV circumferential and/or longitudinal shortening may be impaired in these patients despite LV ejection fraction is preserved. We focused on prevalence and factors associated with combined impairment of circumferential and longitudinal shortening (C&L) in asymptomatic AS patients.

METHODS

Echocardiographic and clinical data from 200 patients with asymptomatic AS of any degree without history of heart failure and normal LV ejection fraction were analyzed. C&L were evaluated by mid-wall shortening (MS) and tissue Doppler mitral annular peak systolic velocity (S'), and classified low if <16.5% and if <8.5 cm/sec, respectively (10th percentiles of controls).

RESULTS

Combined C&L dysfunction was detected in 72 patients (36%). The variables associated with this condition were higher LV mass (OR 1.02 [CI 1.01-1.04], P = 0.03), concentric LV geometry (OR 4.30 [CI 1.79-10.34], P = 0.001), increasing pulmonary artery wedge pressure (by E/e' ratio; OR 1.11 [CI 1.04-1.19], P = 0.001). The relation of MS and peak S' was linear and slightly significant in the whole population (r = 0.23; F statistic=0.001), absent in patients with C&L dysfunction (r = 0.04; F = ns), negative (linear model) in the subgroup of patients without C&L dysfunction (r = -0.22; F = 0.02).

CONCLUSIONS

C&L dysfunction is present in more than one-third of patients with asymptomatic AS and is associated with concentric LV geometry and higher degree of diastolic dysfunction. The relation between MS and peak S' largely varies in the subgroups with different C&L function.

Sex differences in cardiovascular outcome during progression of aortic valve stenosis

Objective

Women with severe aortic valve stenosis (AS) have better LV systolic function and more concentric LV geometry than their male counterparts. However, sex differences in cardiovascular (CV) outcome during progression of AS have not been reported from a longitudinal prospective study.

Methods

Doppler echocardiography and CV events were recorded during a median of 4.0 years in 979 men and 632 women aged 28–86 (mean 67±10) years in the Simvastatin Ezetimibe in Aortic Stenosis (SEAS) study. LV systolic function was assessed by EF and midwall shortening (MWS). Study outcomes were AS-related events, ischaemic CV events and total mortality.

Results

The annular cumulative incidence of AS events, ischaemic CV events and death was 8.1%, 3.4% and 2.8% in women, and 8.9%, 4.4% and 2.4% in men, respectively. Women and men had similar AS progression rate whether measured by peak jet velocity, mean gradient or valve area. In multivariate analyses, female sex independently predicted less reduction in LV MWS and EF during follow-up (both p<0.05). In time-varying Cox analyses, women had a 40% lower rate of ischaemic CV events (95% CI 21% to 54%), in particular, more than 50% lower rate of stroke and coronary artery bypass grafting, and a 31% lower all-cause mortality (95% CI 1% to 51%), independent of active study treatment, age and hypertension, as well as time-varying valve area, low systolic function and abnormal LV geometry. AS event rate did not differ by sex.

Conclusions

In the SEAS study, women and men had similar rates of AS progression and AS-related events. However, women had lower total mortality and ischaemic CV event rate than men independent of confounders.

Trial registration number

ClinicalTrials.gov identifier: NCT00092677.

Impact of obesity and nonobesity on grading the severity of aortic valve stenosis

We tested the hypothesis that the disproportionate increase of body surface area in obesity may lead to the overestimation of aortic stenosis (AS) severity when the aortic valve area (AVA) is indexed (AVAI) for body surface area in 1,524 patients enrolled in the Simvastatin and Ezetimibe in AS study. Obesity was defined as a body mass index of ≥30 kg/m(2). Peak aortic jet velocity, mean aortic gradient, AVA, and energy loss (EL) did not differ, although AVAI and EL indexed (ELI) for body surface area were significantly smaller in the obese group (n = 321) compared with the nonobese (n = 1,203) group (both p <0.05). Severe AS by AVAI (<0.6 cm(2)/m(2)) but nonsevere by AVA (>1.0 cm(2); AVAI/AVA discordance) was found in 15% of the patients, whereas severe AS by ELI (<0.6 cm(2)/m(2)) but nonsevere by EL (>1.0 cm(2); ELI/EL discordance) was found in 9% of the patients. Obesity was associated with a 2.4-fold higher prevalence of AVAI/AVA discordance and a 1.6-fold higher prevalence of ELI/EL discordance. Discordant grading was also associated with male gender, larger body size, higher mean aortic gradient, and stroke volume (all p <0.05). During a median follow-up of 4.3 years, 419 patients were referred for aortic valve replacement and 177 patients died or were hospitalized because of heart failure. In the Cox regression analyses, AVAI/AVA discordance was associated with a 28% higher rate of aortic valve replacement (p <0.05) but did not predict the rate of combined death and hospitalization for heart failure. In conclusion, using AVAI and ELI for the grading of stenosis in patients with obesity may lead to overestimation of true AS severity.

Parallel improvement of left ventricular geometry and filling pressure after transcatheter aortic valve implantation in high risk aortic stenosis: comparison with major prosthetic surgery by standard echo Doppler evaluation

Purpose

The effect of Transcatheter Aortic Valve Implantation (TAVI) on left ventricular (LV) geometry and function was compared to traditional aortic replacement (AVR) by major surgery.

Methods

45 patients with aortic stenosis (AS) undergoing TAVI and 33 AVR were assessed by standard echo Doppler the day before and 2 months after the implantation. 2D echocardiograms were performed to measure left ventricular (LV) mass index (LVMi), relative wall thickness (RWT), ejection fraction (EF) and the ratio between transmitral E velocity and early diastolic velocity of mitral annulus (E/e’ ratio). Valvular-arterial impedance (Zva) was also calculated.

Results

At baseline, the 2 groups were comparable for blood pressure, heart rate, body mass index mean transvalvular gradient and aortic valve area. TAVI patients were older (p<0.0001) and had greater LVMi (p<0.005) than AVR group. After 2 months, both the procedures induced a significant reduction of transvalvular gradient and Zva but the decrease of LVMi and RWT was significant greater after TAVI (both p<0.0001). E/e’ ratio and EF were significantly improved after both the procedure but E/e’ reduction was greater after TAVI (p<0.0001). TAVI exhibited greater percent reduction in mean transvalvular gradient (p<0.05), Zva (p<0.02), LVMi (p<0.0001), RWT (p<0.0001) and E/e’ ratio (p<0.0001) than AVR patients. Reduction of E/e’ ratio was positively related with reduction of RWT (r = 0.46, p<0.002) only in TAVI group, even after adjusting for age and percent reduction of Zva (r =0.43, p<0.005).

Conclusions

TAVI induces a greater improvement of estimated LV filling pressure in comparison with major prosthetic surgery, due to more pronounced recovery of LV geometry, independent on age and changes of hemodynamic load.

Prognostic value of energy loss index in asymptomatic aortic stenosis

BACKGROUND

Aortic valve area index adjusted for pressure recovery (energy loss index [ELI]) has been suggested as a more accurate measure of aortic stenosis (AS) severity, but its prognostic value has not been determined in a prospective study.

METHODS AND RESULTS

The relation between baseline ELI and rate of aortic valve events and combined total mortality and hospitalization for heart failure resulting from the progression of AS was assessed by multivariate Cox regression and reclassification analysis in 1563 patients with initial asymptomatic AS in the Simvastatin and Ezetimibe in Aortic Stenosis (SEAS) study. During 4.3 years follow-up, a total of 498 aortic valve events and 181 combined total mortalities and hospitalizations for heart failure caused by the progression of AS occurred. In Cox regression analyses, 1-cm(2)/m(2) lower baseline ELI predicted a 2-fold higher risk both for aortic valve events and for combined total mortality and hospitalization for heart failure independently of baseline peak aortic jet velocity or mean aortic gradient and independently of aortic root size (all P<0.05). In reclassification analysis, ELI improved the prediction of aortic valve events by 13% (95% confidence interval, 5-19), whereas the prediction of combined total mortality and hospitalization for heart failure resulting from the progression of AS did not improve significantly.

CONCLUSIONS

In asymptomatic AS patients without known atherosclerotic disease or diabetes mellitus, ELI provides independent and additional prognostic information to that derived from conventional measures of AS severity, suggesting that ELI should be measured in such patients.

CLINICAL TRIAL REGISTRATION INFORMATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00092677.

Global left ventricular load in asymptomatic aortic stenosis: covariates and prognostic implication (the SEAS trial)

Introduction

Valvuloarterial impedance (Zva) is a measure of global (combined valvular and arterial) load opposing left ventricular (LV) ejection in aortic stenosis (AS). The present study identified covariates and tested the prognostic significance of global LV load in patients with asymptomatic AS.

Methods

1418 patients with mild-moderate, asymptomatic AS in the Simvastatin Ezetimibe in Aortic Stenosis (SEAS) study were followed for a mean of 43±14 months during randomized, placebo-controlled treatment with combined simvastatin 40 mg and ezetimibe 10 mg daily. High global LV load was defined as Zva >5 mm Hg/ml/m². The impact of baseline global LV load on rate of major cardiovascular (CV) events, aortic valve events and total mortality was assessed in Cox regression models reporting hazard ratio (HR) and 95% Confidence Intervals (CI).

Results

High global LV load was found in 18% (n=252) of patients and associated with female gender, higher age, hypertension, more severe AS and lower ejection fraction (all p<0.05). A total of 476 major CV events, 444 aortic valve events and 132 deaths occurred during follow-up. In multivariate Cox regression analyses, high global LV load predicted higher rate of major CV events (HR 1.35 [95% CI 1.08-1.71], P=0.010) and aortic valve events (HR 1.41 [95% CI 1.12-1.79], P=0.004) independent of hypertension, LV ejection fraction, female gender, age, abnormal LV geometry and AS severity, but failed to predict mortality.

Conclusion

In asymptomatic AS, assessment of global LV load adds complementary information on prognosis to that provided by hypertension or established prognosticators like AS severity and LV ejection fraction.

Hypertension in Aortic Stenosis

The impact of hypertension on left ventricular structure and outcome during progression of aortic valve stenosis has not been reported from a large prospective study. Data from 1616 patients with asymptomatic aortic stenosis randomized to placebo-controlled treatment with combined simvastatin and ezetimibe in the Simvastatin Ezetimibe in Aortic Stenosis Study were used. The primary study end point included combined cardiovascular death, aortic valve events, and ischemic cardiovascular events. Hypertension was defined as history of hypertension or elevated baseline blood pressure. Left ventricular hypertrophy was defined as left ventricular mass/height 2.7 ≥46.7 g/m 2.7 in women and ≥49.2 g/m 2.7 in men and concentric geometry as relative wall thickness ≥0.43. Baseline peak aortic jet velocity and aortic stenosis progression rate did not differ between hypertensive (n=1340) and normotensive (n=276) patients. During 4.3 years of follow-up, the prevalence of concentric left ventricular hypertrophy increased 3 times in both groups. Hypertension predicted 51% higher incidence of abnormal LV geometry at final study visit independent of other confounders ( P <0.01). In time-varying Cox regression, hypertension did not predict increased rate of the primary study end point. However, hypertension was associated with a 56% higher rate of ischemic cardiovascular events and a 2-fold increased mortality (both P <0.01), independent of aortic stenosis severity, abnormal left ventricular geometry, in-treatment systolic blood pressure, and randomized study treatment. No impact on aortic valve replacement was found. In conclusion, among patients with initial asymptomatic mild-to-moderate aortic stenosis, hypertension was associated with more abnormal left ventricular structure and increased cardiovascular morbidity and mortality.

Left atrial systolic force and outcome in asymptomatic mild to moderate aortic stenosis

BACKGROUND AND AIMS

In patients with chronic pressure overload due to hypertension or aortic valve stenosis (AS), higher left atrial systolic force (LASF) is associated with a high-risk cardiovascular (CV) phenotype. We tested LASF as prognostic marker in patients with AS.

METHODS

We used baseline and outcome data from 1,566 patients recruited in the Simvastatin and Ezetimibe in AS (SEAS) study evaluating the effect of placebo-controlled simvastatin and ezetimibe treatment on CV events. The primary outcome was a composite of major CV events, including CV death, aortic valve replacement, nonfatal myocardial infarction, hospitalization for unstable angina, heart failure caused by progression of AS, coronary artery bypass grafting, percutaneous coronary intervention, and nonhemorrhagic stroke. LASF was calculated by Manning's method. High LASF was defined as >95th percentile (50 Kdynes/cm(2)) of the distribution within the study population.

RESULTS

During 4.3 years of follow-up, a major CV event occurred in 38 of 78 patients with high LASF (49%) and in 513 of 1,488 (34%) with normal LASF (P = 0.01). In multivariate Cox regression analysis, high LASF predicted higher rate of major CV events (Hazard ratio 1.43 [95% confidence interval 1.01-2.03] independent of aortic valve area and LV mass index. A simple risk score including absence or presence of these three variables allowed risk stratification into low, intermediate, high and very high risk for major CV events during follow-up (22%, 28%, 38%, and 53%, respectively).

CONCLUSIONS

Higher LASF provides additional prognostic information in patients with asymptomatic mild-to-moderate AS.

Prognostic significance of valvuloarterial impedance and left ventricular longitudinal function in asymptomatic severe aortic stenosis involving three-cuspid valves

The purpose of the present study was to evaluate the role of left ventricular global afterload and various echocardiographic parameters of systolic function in a prospective cohort of 52 asymptomatic patients with severe aortic stenosis (indexed aortic valve area 0.4 ± 0.1 cm²/m²) and normal left ventricular ejection fraction (61 ± 5%). Using 2-dimensional speckle tracking echocardiography, myocardial strain, rotation, and twist were evaluated. The valvuloarterial impedance (Zva) was calculated as a measure of left ventricular global afterload. The predefined end points were the occurrence of symptoms (dyspnea, angina, syncope), aortic valve replacement, and death. At study entry, all patients had decreased longitudinal strain (LS) (-15 ± 4%) and increased circumferential strain (-22 ± 5%), twist (24 ± 7°), and Zva (5.8 ± 2 mm Hg/ml/m²). Increased Zva was closely associated with the circumferential strain increase (r = 0.59, p = 0.02) and LS decrease (r = -0.56, p = 0.016). In contrast, no relation was found between myocardial function and transaortic gradients. During follow-up (11 ± 7.5 months), on univariate Cox regression analysis, the predictors of events were the left ventricular ejection fraction (p = 0.02), mass index (p = 0.01), LS (p < 0.0001), radial strain (p = 0.04), and Zva (p = 0.0002). On multivariate Cox regression analysis, only the global LS (p = 0.03) and Zva (p = 0.03) were independently associated with the combined end point. Using receiver operating characteristic curve analysis, a LS of ≤-18% (sensitivity 96%, specificity 73%) and a Zva of ≥ 4.7 mm Hg/ml/m² (sensitivity 100%, specificity 91%) were identified as the best cutoff values to be associated with events. In conclusion, in asymptomatic patients with severe aortic stenosis, the degree of global afterload and its consequences on longitudinal function might play a role in clinical practice.