Inappropriately high left-ventricular mass in asymptomatic mild-moderate aortic stenosis

Left Ventricular Mass, Myocardial Structure, and Function in Severe Aortic Stenosis: an Echocardiographic and Cardiac Magnetic Resonance Imaging Study

In severe aortic stenosis (AS), there are conflicting data on the prognostic implications of left ventricular (LV) hypertrophy (LVH). We aimed to characterize the LV geometry, myocardial matrix structural changes, and prognostic stratification using cardiac magnetic resonance imaging (CMR) and echocardiography in subjects with severe AS with and without LVH. Consecutive patients who had severe isolated AS and sufficient quality echocardiography and CMR within 6 months of each other were evaluated for LVH, cardiac structure, morphology, and late gadolinium-enhancement imaging. Kaplan-Meier curves, linear models, and proportional hazards models were used for prognostic stratification. There were 93 patients enrolled (mean age 74 ± 11 years, 48% female), of whom 38 (41%) had a normal LV mass index (LVMI), 41 (44%) had LVH defined at CMR by LVMI >2 SD higher than normal, and 14 (15% of the total) with >4 SD higher than the reference LVMI (severely elevated). The Society of Thoracic Surgeons scores were similar among the LVMI groups. Compared with those with normal LVMI, patients with LVH had higher LV end-diastolic and end-systolic volumes, increased late gadolinium-enhancement burden, and lower LV ejection fraction. Most notably, CMR feature-tracking global radial strain, 2-dimensional speckle-tracking echocardiography global longitudinal strain, and left atrial reservoir function were significantly worse. On the survival analyses, LVMI was not associated with a composite of all-cause mortality and/or heart failure hospitalization. In conclusion, compared with normal LVMI, elevated LVMI was not associated with a higher risk of adverse outcomes.

A simplified cardiac damage staging predicts the outcome of patients undergoing TAVR-A multicenter analysis

BACKGROUND

A significant number of patients with severe aortic stenosis (AS) undergoing transcatheter aortic valve replacement (TAVR) suffer from extra-aortic cardiac damage. Few studies have investigated strategies to quantify cardiac damage and stratify patients accordingly in different risk groups. The aim of this retrospective multicenter study was to provide a user-friendly simplified staging system based on the proposed classification system of Généreux et al. as a tool to evaluate the prognosis of patients undergoing TAVR more easily. Moreover, we analyzed changes in cardiac damage after TAVR.

METHODS

We assessed cardiac damage in patients, who underwent TAVR at the Heart Center Bonn or Düsseldorf, using pre- and postprocedural transthoracic echocardiography. Patients were assigned to the staging system proposed by Généreux et al. according to the severity of their baseline cardiac damage. Based on the established system, we created a simplified staging system to facilitate improved applicability. Finally, we compared clinical outcomes between the groups and evaluated changes in cardiac damage after TAVR.

RESULTS

A total of 933 TAVR patients were included in the study. We found a significant association between cardiac damage and 1-year all-cause mortality (stage 0: 0% vs. stage 1: 3% vs. stage 2: 6.6%; p < 0.009). In multivariate analysis, cardiac damage was an independent predictor of 1-year all-cause mortality (hazard ratio: 2.0, 95% confidence interval: 1.1-3.8; p = 0.03).

CONCLUSIONS

In patients undergoing TAVR, cardiac damage is associated with enhanced mortality. A simplified staging system can help identify patients at high risk for an adverse outcome.

New Evidence About Aortic Valve Stenosis and Cardiovascular Hemodynamics

Aortic stenosis (AS) is the most common degenerative valvular disease in western word. In patients with severe AS, small changes in aortic valve area can lead to large changes in hemodynamics. The correct understanding of cardiac hemodynamics and its interaction with vascular function is of paramount importance for correct identification of severe AS and to plan effective strategies for its treatment. In the current review with highlight the importance of pressure recovery phenomenon and valvular arterial impedance as novel tools in the evaluation of patients with aortic stenosis.

Moderate Aortic Stenosis: What is it and When Should We Intervene?

Current guidelines recommend aortic valve replacement in patients with severe aortic stenosis in the presence of symptoms or a left ventricular ejection fraction <50%. However, patients with less than severe aortic stenosis may also experience symptoms and recent literature suggests that the prognosis is not as benign as previously reported. There are no recommendations for patients with moderate aortic stenosis and left ventricular dysfunction, despite the high associated morbidity and mortality. There is also some evidence that these patients may benefit from early aortic valve intervention. It is recognised that aortic stenosis not only affects the valve but also has a complex myocardial response. This review discusses the natural history of moderate aortic stenosis along with the role of multimodality imaging in risk stratification in these patients.

Inadequately low left ventricular mass in patients with significant aortic stenosis predicts favourable prognostic outcomes

In patients with significant aortic stenosis (AS), the prognostic effect of the increase in left ventricular mass (LVM) in relation to one's hemodynamic load has been described. Inappropriately high LVM has been shown to predict adverse cardiovascular events. However, little is known about the prognostic impact of inadequately low LVM (i-lowLVM) in patients with significant AS. I-lowLVM was defined as the measured LVM < 73% of the predicted LVM based on sex, stroke work and height from the reference adult population, used in previous established studies. For outcome analysis, the end-point was defined as all-cause mortality, aortic valve replacement and/or admission for congestive heart failure. Kaplan-Meier curves and multivariable Cox regression models were constructed to compare outcomes on follow-up. During the follow-up (4.5 ± 4.1 years), 132 patients (11.1%) had i-lowLVM, 868 (73.1%) had adequate-LVM, 188 (15.8%) had inappropriately high LVM. Outcome analysis only included patients with i-lowLVM and adequate-LVM (N = 1000). An adverse composite event occurred in 41.7% of the i-lowLVM group and 52.4% of the adequate-LVM group (p = 0.021). Event-free survival in patients with i-lowLVM and appropriate-LVM was 76% versus 68% at 2-year, 55% versus 46% at 4-year, 33% versus 27% at 6-year, 20% versus 17% at 8-year, and 17% versus 11% at 10-year follow-up, respectively (p < 0.001). Cox analysis revealed that i-lowLVM was independently associated with lower composite adverse outcome (HR 0.624, 95% CI 0.460-0.846, p = 0.002) after adjusting for sex, age, ejection fraction, ischemic heart disease, diabetes and transaortic valve mean gradient. In the separate Cox subanalyses, the presence of i-lowLVM remained a predictor of lower composite adverse outcome in the severe AS subgroup (HR 0.587, 95% CI 0.396-0.870, p = 0.008), and the LVH subgroup (HR 0.574, 95% CI 0.401-0.824, p = 0.003) after adjusting for confounders. I-lowLVM despite significant AS may represent a distinct group that is associated with improved survival outcomes independent of other prognostic covariates.

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.

Management of patients with combined arterial hypertension and aortic valve stenosis: a consensus document from the Council on Hypertension and Council on Valvular Heart Disease of the European Society of Cardiology, the European Association of Cardiovascular Imaging (EACVI), and the European Association of Percutaneous Cardiovascular Interventions (EAPCI)

Aortic valve stenosis (AS) is the third most common cardiovascular disease. The prevalence of both AS and arterial hypertension increases with age, and the conditions therefore often co-exist. Co-existence of AS and arterial hypertension is associated with higher global left ventricular (LV) pressure overload, more abnormal LV geometry and function, and more adverse cardiovascular outcome. Arterial hypertension may also influence grading of AS, leading to underestimation of the true AS severity. Current guidelines suggest re-assessing patients once arterial hypertension is controlled. Management of arterial hypertension in AS has historically been associated with prudence and concerns, mainly related to potential adverse consequences of drug-induced peripheral vasodilatation combined with reduced stroke volume due to the fixed LV outflow obstruction. Current evidence suggests that patients should be treated with antihypertensive drugs blocking the renin-angiotensin-aldosterone system, adding further drug classes when required, to achieve similar target blood pressure (BP) values as in hypertensive patients without AS. The introduction of transcatheter aortic valve implantation has revolutionized the management of patients with AS, but requires proper BP management during and following valve replacement. The purpose of this document is to review the recent evidence and provide practical expert advice on management of hypertension in patients with AS.

Better Myocardial Function in Aortic Stenosis with Low Left Ventricular Mass: A Mechanism of Protection against Heart Failure Regardless of Stenosis Severity?

About one-tenth to one-third of patients with severe aortic stenosis (AS) do not develop left ventricular hypertrophy (LVH). Intriguingly, the absence of LVH despite severe AS is associated with lower prevalence of heart failure (HF), which challenges the classical notion of LVH as a beneficial compensatory response. Notably, the few studies that have attempted to characterize AS subjects with inadequately low left ventricular (LV) mass relative to LV afterload (i-lowLVM) described better prognosis and enhanced LV performance in AS associated with i-lowLVM, but those reports were limited to severe AS. Our aim was to compare myocardial function between moderate and severe AS with i-lowLVM. We retrospectively analyzed in-hospital records of 225 clinically stable nondiabetic patients with isolated moderate or severe degenerative AS in sinus rhythm, free of coexistent diseases. Subjects with i-lowLVM were compared to those with appropriate or excessive LVM (a/e-LVM), defined on the basis of the ratio of a measured LVM to the LVM predicted from an individual hemodynamic load. Patients with i-lowLVM and a/e-LVM did not differ in aortic valve area, LV end-diastolic diameter (LVd, a measure of LV preload), and circumferential end-systolic LV wall stress (cESS), an estimate of LV afterload. Compared to a/e-LVM, patients with i-lowLVM had increased LV ejection fraction (EF) and especially higher LV midwall fractional shortening (a better index of LV myocardial function than EF in concentric LV geometry) (p < 0.001–0.01), in both moderate and severe AS. LVd and cESS were similar in the four subgroups of the study subjects, i.e., moderate AS with i-lowLVM, moderate AS with a/e-LVM, severe AS with i-lowLVM, and severe AS with a/e-LVM (p > 0.6). Among patients with i-lowLVM, LVM did not differ significantly between moderate and severe AS (p > 0.4), while in those with a/e-LVM, LVM was increased in severe versus moderate AS (p < 0.001). In conclusion, the association of the low-LVM phenotype with better myocardial contractility may already develop in moderate AS. Additionally, cESS appears to be a controlled variable, which is kept constant over AS progression irrespective of LVM category, but even when controlled (by increasing LVM), is not able to prevent deterioration of LV function. Whether improved myocardial performance contributes to favorable prognosis and the preventive effect against HF in AS without LVH, remains to be studied.

Association of Inadequately Low Left Ventricular Mass with Enhanced Myocardial Contractility in Severe Degenerative Aortic Stenosis

Background: Left ventricular hypertrophy (LVH), traditionally considered an adaptive mechanism that is aimed at the maintenance of LV systolic function, is absent in 10%–35% of patients with severe aortic stenosis (AS). Our aim was to estimate the clinical and hemodynamic characteristics in patients with severe AS and absent LVH, or inadequately low LV mass (i-lowLVM) relative to an individual hemodynamic load. Methods: We retrospectively analyzed in-hospital records of 100 patients with pure severe degenerative AS, preserved LV systolic function and without relevant coexistent diseases, except for well-controlled hypertension or diabetes. Results: Clinical characteristics were similar in patients with and without LVH, as well as those with and without i-lowLVM, except for slightly lower GFR at i-lowLVM. When compared to their counterparts, subjects without LVH or with i-lowLVM had smaller LV cavities, decreased LV wall thicknesses and higher EF. There were no significant differences in stenosis severity and indices of afterload (valvulo-arterial impedance and circumferential end-systolic LV wall stress), according to the presence or absence of either LVH or i-lowLVM. However, LV fractional shortening at the midwall level was elevated only in patients with i-lowLVM, but not in those without LVH, compared to the remainder (15.8 ± 3.3 vs. 12.9 ± 3.2%, p < 0.001 for those with and without i-lowLVM, respectively; 13.7 ± 3.7 vs. 13.8 ± 3.6% for LVH presence and absence, p = 0.9). Conclusions: Inadequately low LVM relative to the individual hemodynamic load could potentially reflect a different mode of the LV response to severe AS, associated with enhanced load-independent LV systolic performance, i.e., better LV contractility. If confirmed in a large series of patients, our small preliminary study may add to the possible mechanisms of a previously reported counterintuitive tendency of a lower, not higher, risk of adverse outcome in patients with low LV mass despite severe AS. Prospective studies are warranted, in order to determine a potential utility of LVM inadequacy in the risk stratification of patients with AS.

Is left ventricular hypertrophy a friend or foe of patients with aortic stenosis?

Left ventricular hypertrophy (LVH) is traditionally considered a physiological compensatory response to LV pressure overload, such as hypertension and aortic stenosis (AS), in an effort to maintain LV systolic function in the face of an increased afterload. According to the Laplace law, LV wall thickening lowers LV wall stress, which in turn would be helpful to preserve LV systolic performance. However, numerous studies have challenged the notion of LVH as a putative beneficial adaptive mechanism. In fact, the magnitude of LVH is associated with higher cardiovascular morbidity and mortality, especially when LVH is disproportionate to LV afterload. We have briefly reviewed: first, the importance of non-valvular factors, beyond AS severity, for total LV afterload and symptomatic status in AS patients; second, associations of excessive LVH with LV dysfunction and adverse outcome in AS; third, prognostic relevance of the presence or absence of pre-operative LVH in patients referred for aortic valve surgery; fourth, time course, determinants and prognostic implications of LVH regression and LV function recovery after surgical valve replacement and transcatheter aortic valve implantation (TAVI) with a focus on TAVI-specific effects; fifth, the potential of medical therapy to modulate LVH before and after surgical or interventional treatment for severe AS, a condition perceived as a relative contraindication to renin-angiotensin system blockade.

Prevalence and factors related to inappropriately high left ventricular mass in patients with rheumatoid arthritis without overt cardiac disease

OBJECTIVES

Due to the chronic inflammatory status, specific neuro-hormones and progression of arterial stiffness, patients with rheumatoid arthritis (RA) are exposed to the development of excessive left ventricular mass disproportionate to the need to compensate left ventricular load. This condition, named inappropriately high left ventricular mass (iLVM), is associated with unfavorable prognosis in patients with hypertension, aortic stenosis or diabetes. In this study, we assessed prevalence and factors associated with iLVM in a large cohort of patients with RA and tested the hypothesis that RA per se is a condition related to iLVM.

METHODS

We prospectively analyzed 235 RA patients without overt cardiac disease recruited between January and December 2014, who were compared with 235 controls matched for age, sex, BMI, prevalence of hypertension and diabetes. iLVM was defined as measured/predicted LVM ratio above 123%. LVM was predicted in each individual by using a simple equation considering height, sex and left ventricular work.

RESULTS

iLVM was detected in 150 RA patients (64%) and in 30 controls (15%; P < 0.001). In patients with RA, the variables independently associated with iLVM emerged by multivariate logistic regression analysis were left ventricular systolic dysfunction measured as mid-wall shortening and concentric left ventricular geometry. Considering both groups of patients with RA and matched controls, RA was the strongest variable related to iLVM (odds ratio 3.37, 95% confidence interval 1.37-8.31, P = 0.008).

CONCLUSIONS

Two-thirds of patients with RA without overt cardiac disease have iLVM, which is associated with left ventricular systolic dysfunction and concentric geometry. RA per se is a condition closely related to iLVM.

From Left Ventricular Hypertrophy to Dysfunction and Failure

Left ventricular hypertrophy (LVH) is growth in left ventricular mass caused by increased cardiomyocyte size. LVH can be a physiological adaptation to strenuous physical exercise, as in athletes, or it can be a pathological condition, which is either genetic or secondary to LV overload. Physiological LVH is usually benign and regresses upon reduction/cessation of physical activity. Pathological LVH is a compensatory phenomenon, which eventually may become maladaptive and evolve towards progressive LV dysfunction and heart failure (HF). Both interstitial and replacement fibrosis play a major role in the progressive decompensation of the hypertrophied LV. Coronary microvascular dysfunction (CMD) and myocardial ischemia, which have been demonstrated in most forms of pathological LVH, have an important pathogenetic role in the formation of replacement fibrosis and both contribute to the evolution towards LV dysfunction and HF. Noninvasive imaging allows detection of myocardial fibrosis and CMD, thus providing unique information for the stratification of patients with LVH. (Circ J 2016; 80: 555-564).

Left ventricular hypertrophy in valvular aortic stenosis: mechanisms and clinical implications

Valvular aortic stenosis is the second most prevalent adult valve disease in the United States and causes progressive pressure overload, invariably leading to life-threatening complications. Surgical aortic valve replacement and, more recently, transcatheter aortic valve replacement effectively relieve the hemodynamic burden and improve the symptoms and survival of affected individuals. However, according to current American College of Cardiology/American Heart Association guidelines on the management of valvular heart disease, the indications for aortic valve replacement, including transcatheter aortic valve replacement, are based primarily on the development of clinical symptoms, because their presence indicates a dismal prognosis. Left ventricular hypertrophy develops in a sizeable proportion of patients before the onset of symptoms, and a growing body of literature demonstrates that regression of left ventricular hypertrophy resulting from aortic stenosis is incomplete after aortic valve replacement and associated with adverse early postoperative outcomes and worse long-term outcomes. Thus, reliance on the development of symptoms alone without consideration of structural abnormalities of the myocardium for optimal timing of aortic valve replacement potentially constitutes a missed opportunity to prevent postoperative morbidity and mortality from severe aortic stenosis, especially in the face of the quickly expanding indications of lower-risk transcatheter aortic valve replacement. The purpose of this review is to discuss the mechanisms and clinical implications of left ventricular hypertrophy in severe valvular aortic stenosis, which may eventually move to center stage as an indication for aortic valve replacement in the asymptomatic patient.