Management of Asymptomatic Severe Aortic Stenosis

Asymptomatic Severe Aortic Stenosis: Contemporary Evaluation and Management

Aortic stenosis (AS) is the most prevalent valvular heart disease in developed countries and most prevalent in the elderly. According to the current guidelines, intervention is recommended in symptomatic severe AS; however, in asymptomatic patients, aortic valve replacement (AVR) is considered when symptoms appear or the left ventricular dysfunction occurs, but the evidence supports these indications are poor. The optimal timing and modality of intervention in asymptomatic severe AS (ASAS) remain controversial. Earlier AVR in certain scenarios has been increasingly supported by some groups before subclinical irreversible myocardial damage occurs. In addition, the continuous advancement of percutaneous and surgical approaches where associated with a substantial decrease in mortality and perioperative complications which made many authors advocate for early intervention in those patients. Our review highlights the contemporary evaluation and management of ASAS and summarizes the current scientific evidence regarding optimal timing for intervention and indications for early AVR in such patients.

Prognostic Value of the Three-Dimensional Right Ventricular Ejection Fraction in Patients With Asymptomatic Aortic Stenosis

Background: The right ventricular (RV) function is an important prognostic marker of asymptomatic aortic stenosis (AS). However, previous publications have not addressed the additive value of conventional RV parameters over left heart parameters. Whether three-dimensional echocardiography (3DE)-derived RV ejection fraction (RVEF) has prognostic utility independent of 3DE derived left heart parameters is also unknown. We investigated the prognostic utility of 3DE RVEF in patients with asymptomatic AS.

Methods: We retrospectively selected 392 asymptomatic AS patients. RVEF, left ventricular ejection fraction (LVEF) and left atrial volumes (LAVs) were measured using 3DE datasets. We determined the association of those parameters, as well as of aortic valve replacement (AVR), and Charlson's comorbidity index with cardiac events. We also analyzed whether RVEF has incremental value over two-dimensional echocardiography (2DE) RV parameters.

Results: During a median follow-up of 27 months, 57 patients developed cardiac events, and 68 patients received AVR. Univariate Cox proportional hazard analysis revealed that RVEF was associated with cardiac events (p < 0.001). Multivariate analysis revealed that RVEF was significantly associated with cardiac events (p < 0.001) even after adjusting for AVR, Charlson's comorbidity index, LVEF, LAV, E/e', and indexed aortic valve area (iAVA). An incremental value of RVEF over left heart parameters was also demonstrated using a nested regression model. Classification and regression-tree analysis selected RVEF first with a cut-off value of 41%. RVEF had incremental value over iAVA, LVEF, and 2DE conventional RV parameters for its association with future outcomes.

Conclusions: 3DE RVEF had significant prognostic value even after adjusting for comorbidities, left heart parameters, and conventional 2DE RV parameters in asymptomatic aortic stenosis.

Diastolic Function and Clinical Outcomes After Transcatheter Aortic Valve Replacement: PARTNER 2 SAPIEN 3 Registry

BACKGROUND

Few studies have evaluated if diastolic function could predict outcomes in patients with aortic stenosis.

OBJECTIVES

The authors aimed to assess the association between diastolic dysfunction (DD) and outcomes in patients with aortic stenosis undergoing transcatheter aortic valve replacement (TAVR).

METHODS

Baseline, 30-day, and 1- and 2-year transthoracic echocardiograms from the PARTNER (Placement of Aortic Transcatheter Valves) 2 SAPIEN 3 registry were analyzed by a consortium of core laboratories and divided into the American Society of Echocardiography DD groups.

RESULTS

Among the 1,750 included, 682 (54.4%) had grade 1 DD, 352 (28.1%) had grade 2 DD, 168 (13.4%) had grade 3 DD, and 51 (4.1%) had indeterminate DD grade. Incremental baseline grades of DD were associated with an increase in combined 1- and 2-year cardiovascular (CV) death/rehospitalization (all p < 0.002) and all-cause death at 2 years (p = 0.01) but not at 1 year. Improvement in DD grade/grade 1 DD at 30 days post-TAVR was seen in 70.8% patients. Patients with improvement in ≥1 grade of DD/grade 1 DD had reduced 1-year CV death/rehospitalization (p < 0.001) and increased 2-year survival (p = 0.01). Baseline grade 3 DD was a predictor of 1-year CV death/rehospitalization (hazard ratio: 2.73; 95% confidence interval: 1.07 to 6.98; p = 0.04). Improvement in DD grade/grade 1 DD at 30 days was protective for 1-year CV death/rehospitalizations (hazard ratio: 0.39; 95% confidence interval: 0.19 to 0.83; p = 0.01).

CONCLUSIONS

In the PARTNER 2 SAPIEN 3 registry, baseline DD was a predictor of up to 2 years clinical outcomes in patients who underwent TAVR. Improvement in DD grade at 30 days was associated with improvement in short-term clinical outcomes. (The PARTNER II Trial: Placement of AoRTic TraNscathetER Valves II - PARTNER II - PARTNERII - S3 Intermediate [PARTNERII S3i]; NCT03222128; PARTNER II Trial: Placement of AoRTic TraNscathetER Valves II - High Risk and Nested Registry 7 [PII S3HR/NR7]; NCT03222141).

Doppler assessment of aortic stenosis: a 25-operator study demonstrating why reading the peak velocity is superior to velocity time integral

Aims

Measurements with superior reproducibility are useful clinically and research purposes. Previous reproducibility studies of Doppler assessment of aortic stenosis (AS) have compared only a pair of observers and have not explored the mechanism by which disagreement between operators occurs. Using custom-designed software which stored operators’ traces, we investigated the reproducibility of peak and velocity time integral (VTI) measurements across a much larger group of operators and explored the mechanisms by which disagreement arose.

Methods and results

Twenty-five observers reviewed continuous wave (CW) aortic valve (AV) and pulsed wave (PW) left ventricular outflow tract (LVOT) Doppler traces from 20 sequential cases of AS in random order. Each operator unknowingly measured each peak velocity and VTI twice. VTI tracings were stored for comparison. Measuring the peak is much more reproducible than VTI for both PW (coefficient of variation 10.1 vs. 18.0%; P < 0.001) and CW traces (coefficient of variation 4.0 vs. 10.2%; P < 0.001). VTI is inferior because the steep early and late parts of the envelope are difficult to trace reproducibly. Dimensionless index improves reproducibility because operators tended to consistently over-read or under-read on LVOT and AV traces from the same patient (coefficient of variation 9.3 vs. 17.1%; P < 0.001).

Conclusion

It is far more reproducible to measure the peak of a Doppler trace than the VTI, a strategy that reduces measurement variance by approximately six-fold. Peak measurements are superior to VTI because tracing the steep slopes in the early and late part of the VTI envelope is difficult to achieve reproducibly.

Value of ejection fraction/velocity ratio in the prognostic stratification of patients with asymptomatic aortic valve stenosis

BACKGROUND

The ejection fraction/velocity ratio (EFVR) is a simple function-corrected index of aortic stenosis severity with a good correlation with aortic valve area measured using the Gorlin formula at cardiac catheterization. It is calculated by dividing left ventricular ejection fraction (LVEF) to 4 × (peak jet velocity)² .

OBJECTIVE

Our aim was to evaluate the value of EFVR in predicting adverse events in patients with asymptomatic aortic stenosis.

METHODS

We analyzed the clinical and echocardiographic data of 216 asymptomatic patients with at least moderate aortic stenosis (AVA ≤ 1.5 cm² ). The primary end-point was cardiovascular death or aortic valve replacement.

RESULTS

There were 119 (55%) men and mean age was 68 ± 10 years. The mean follow-up time was 4.2 ± 1.6 years (median 4.3 years). During follow-up, the composite end-point of death or aortic valve replacement was reached in 105 patients (49%). Using multivariate Cox regression analysis, EFVR and valvulo-arterial impedance emerged as independent variables associated with outcome (P < 0.001 and P = 0.001, respectively). In the subgroup of patients with severe aortic stenosis (AVA < 1 cm² ), EFVR ≤ 0.9 was associated with an increased hazard ratio for the composite end-point of mortality and aortic valve replacement (HR 2.14, 95% CI: 1.15-4.0, P = 0.017), even after adjusting for aortic valve area.

CONCLUSIONS

In patients with asymptomatic moderate to severe aortic stenosis, EFVR is useful for risk stratification. Our results suggest that incorporating EFVR in the evaluation of patients with asymptomatic aortic stenosis might help identify those who are most likely to benefit from early elective aortic replacement.

Risk stratification of severe aortic stenosis according to new guidelines: long term outcomes

Background

Current ESC and ACC/AHA guidelines for the management of valvular heart disease assign a class Ia indication for aortic valve replacement (AVR) only to patients with symptomatic severe aortic valve stenosis and asymptomatic patients with depressed left ventricular ejection fraction (LVEF <50%) or positive exercise test. We examined the long-term outcomes for patients undergoing AVR for aortic stenosis over a 11-year period at our institution compared to current international guidelines for AVR.

Methods

Patients who had undergone isolated AVR for severe aortic valve stenosis between January 2001 and December 2012 were selected. The population was divided into subgroups based on preoperative LVEF (< or ≥50%) and on presence/absence of symptoms (NYHA =I or ≥II, respectively).

Results

We identified 607 patients with a median follow-up (FU) time of 5.75 years (IQR 3.24-8.00 years). The presence of symptoms did not have a significant impact on cardiovascular mortality (P=0.201). Patients with LVEF <50% displayed a higher long-term cardiovascular mortality rate (P=0.015). Multivariate analysis showed that preserved LVEF was a protective factor for asymptomatic patients (P=0.021), while preoperative LVEF did not affect the mortality rate in symptomatic patients (HR 0.88; 95% CI, 0.54-1.44). Correspondingly, asymptomatic patients with reduced LVEF were found to be at a higher risk of long-term mortality compared to the other groups (P=0.011). The only other independent risk factor for death was age (HR 6.46; 95% CI, 2.22-18.76).

Conclusions

According to our data, current international class I indications for symptomatic patients ensure good long-term survival, while class I indications for asymptomatic patients with reduced LVEF are associated with poor long-term survival. Our results suggest that early surgery should also be considered also for asymptomatic patients with preserved LVEF, particularly in cases of very low operative risk.

Prognostic value of area of calcified aortic valve by 2-dimensional echocardiography in asymptomatic severe aortic stenosis patients with preserved left ventricular ejection fraction

We hypothesized that area of calcified aortic valve (ACAV) measured by 2D echocardiography (2DE) can predict future cardiovascular events in asymptomatic severe aortic stenosis (AS).Multidetector computed tomography determined aortic valve calcification load is strongly associated with AS severity but has risks for radiation exposure. Quantification of ACAV by transthoracic 2DE is simple and convenient but its clinical utility has not been extensively studied.We measured ACAV in 124 asymptomatic severe AS patients (80 ± 9 years, 45 males) with preserved left ventricular ejection fraction. ACAV was measured by planimetry from 2D zoomed long axis view of the AV at end-diastole. Patients were followed to record cardiac death (CD) and major adverse cardiovascular events (MACEs).During a median follow-up of 232 days, 17 patients had MACE, including 8 CD. ACAV was significantly larger in patients with event compared to those without (1.14 ± 0.35 cm vs 0.87 ± 0.34 cm, P=.0032). Using receiver operating characteristics derived ACAV of 0.79 cm as cutoff value, Kaplan-Meyer analysis showed it could discriminate high-risk group from low-risk group for future CD (P=.0223, χ = 5.22) and MACE (P = .0054, χ = 7.74).2DE determined ACAV is straightforward and has potential to predict future cardiac events in asymptomatic severe AS patients.

Interaction of renal failure and dyslipidaemia in the development of calcific aortic valve disease in rats

OBJECTIVE

Calcific aortic valve disease (CAVD) is currently the most common heart valve disease worldwide and is known to be an active process. Both renal failure and dyslipidaemia are considered to be promoting factors for the development of valvular calcifications. The aim of this study is to prospectively evaluate the respective contribution and interaction of renal failure and dyslipidaemia on CAVD in a rat model, using echocardiography and compared with histology.

METHODS AND RESULTS

Sixty-eight male Wistar rats were prospectively divided in eight groups, each fed a different diet to induce renal failure alone and combined with hyperlipidaemia or hypercholesterolemia. CAVD was detected and quantified by calibrated integrated backscatter of ultrasound (cIB) and compared with the histological calcium score. The study follow-up was 20 weeks. At the end of the study, the cIB value and the calcium score of the aortic valve were significantly increased in the group with isolated renal failure but not with dyslipidaemia. The combination of renal failure with high cholesterol or high-fat diet did not significantly increase calcifications further.

CONCLUSIONS

Renal failure alone does induce aortic valve calcifications in a rat model of CAVD, whereas dyslipidaemia alone does not. The combination of renal failure with dyslipidaemia does not increase calcification further. These findings suggest that a combination of atherosclerotic and calcifying factors is not required to induce aortic valve calcifications in this model.

Severe and Asymptomatic Aortic Stenosis Management Challenge: Knowing That We Do Not Really Know

OPINION STATEMENT

The clinical management of asymptomatic patients with severe aortic valve stenosis (AS) may be challenging. Indeed, there is substantial controversy over the optimal timing of intervention for these patients, as some advocate early intervention while others urge for a conservative management until symptom onset. In the meantime of randomized clinical trials aiming to compare both strategies of management, an integrative approach including several imaging modalities as well as biomarkers of the myocardial damage may help to improve the risk stratification of patients with asymptomatic severe AS and individualize strategy of treatment. The extent of aortic valve calcification, semi-quantitatively assessed by echocardiography but better fully quantitatively measured by computed tomography (CT), provides incremental value to predict rapid disease progression and adverse event and thus could be a potential trigger for early referral to intervention or guide the timing of clinical follow-up. In addition, the assessment of disease activity using positron emission tomography, combined with CT calcium scoring, may also help to better predict the disease progression. The comprehensive assessment of left ventricular (LV) function using speckle-tracking echocardiography and/or cardiac magnetic resonance may provide useful information regarding the actual repercussion of AS on the myocardium. Besides imaging modalities, the measurement of several circulating biomarkers associated with the extent of the myocardial damage may also improve the risk stratification of asymptomatic patients with severe AS and help guiding management. Finally, it should be emphasized that a personalized medicine, including this comprehensive integrative approach in heart valve clinics, should be advocated for the management of these challenging patients.

Delayed Time to Peak Velocity Is Useful for Detecting Severe Aortic Stenosis

BACKGROUND

Time to peak velocity (TPV) is an echocardiographic variable that can be easily measured and reflects a late peaking murmur, a classic physical finding suggesting severe aortic stenosis (AS). The aim of this study was to investigate the usefulness of TPV to evaluate AS severity.

METHODS AND RESULTS

This study included 700 AS patients, whose aortic valve area (AVA) was <1.5 cm2, and 200 control patients. The TPV was defined as the time from aortic valve opening to when the flow velocity across the aortic valve reaches its peak. AS severity was classified as follows: High gradient severe AS, mean pressure gradient ≥40 mm Hg and AVA index (AVAI) <0.6 cm2/m2; Low gradient severe AS, mean pressure gradient <40 mm Hg, AVAI <0.6 cm2/m2, and dimensionless index <0.25; moderate AS, mean pressure gradient <40 mm Hg, AVAI ≥0.6 cm2/m2. The area under the receiver operating characteristic curve of TPV to predict high gradient severe AS was 0.94 (95% CI: 0.92-0.97, P<0.001). TPV was significantly delayed in low gradient severe AS compared with moderate AS both in patients with preserved (102±13 ms versus 83±13 ms, P<0.001) and with reduced ejection fraction (110±18 ms versus 88±13 ms, P<0.001). Delayed TPV was associated with increased all-cause mortality or need for aortic valve replacement after adjustment for confounders (hazard ratio for first quartile, reference is fourth quartile: 7.31, 95% CI 4.26-12.53, P<0.001).

CONCLUSIONS

TPV is useful to evaluate AS severity and predict poor prognosis of AS patients.

Relation between E/e' ratio and NT-proBNP levels in elderly patients with symptomatic severe aortic stenosis

BACKGROUND

Symptoms in the elderly patients with severe aortic stenosis (AS) and co-morbidities seem to lack in specificity. Therefore, objective parameters for increased left ventricular(LV) filling pressures are needed. The aim of this study was to investigate the correlation between the septal, lateral and average E/e' ratio and the value of the N-terminal pro-hormone of brain natriuretic peptide (NT-proBNP).

METHODS

Two-hundred-fifty consecutive symptomatic patients (mean age 80 ± 8 years, 52% men) with severe AS underwent transthoracic echocardiography and NT-proBNP measurement.

RESULTS

In the overall population the septal E/e' (r = 0,459, r(2) = 0,21, P <0,0001), lateral E/e' (r = 0,322, r(2) = 0,10, P <0,0001), and the average E/e' (r = 0,432, r(2) = 0,18, P <0,0001) were all significantly correlated to NT-proBNP. After the exclusion of patients with confounders (more than mild aortic or mitral regurgitation, severe renal dysfunction, obesity or severe COPD) the septal E/e' (r = 0,584, r(2) = 0,34, P <0,0001), lateral E/e' (r = 0,377, r(2) = 0,14, P <0,0001), and the average E/e' (r = 0,487, r(2) = 0,24, P <0,0001) were all significantly better correlated to NT-proBNP. In obese patients no significant correlations were seen. Previous bypass surgery did not alter the correlations.

CONCLUSIONS

In elderly patients with severe symptomatic AS there is a significant correlation between the E/e' ratio and NT-proBNP, in particular after exclusion of confounders. The correlation was best for the septal E/e' ratio and was preserved in patients with a history of bypass surgery.

Thallium-201 gated single-photon emission tomography for assessing left ventricular volumes and function in patients with aortic valve stenosis: Comparison with echocardiography as the reference standard

Background

Aortic valve stenosis (AS) is characterized by chronic left ventricular pressure overload, leading to left ventricular hypertrophy (LVH). We assessed correlations in left ventricular volumes and function between echocardiography and quantitative gated SPECT (QGS) in patients with AS.

Methods and results

The study population consisted of 28 patients with AS defined as a peak velocity of > 3.0 m/s and 28 age- and sex-matched control subjects. Patients with AS had a peak pressure gradient of 73.4 ± 24.5 mm Hg and a larger LVM index compared to control subjects (115.5 ± 29.2 g/m² vs 78.3 ± 12.1 g/m², p < 0.01). There were good correlations in end-diastolic volume and end-systolic volume between echocardiography and QGS in patients with AS as well as control subjects. Bland–Altman plot for end-systolic volume showed a significant negative slope of − 0.51 in patients with AS. There was a good correlation in ejection fraction between the 2 methods in patients with AS as well as control subjects. However, Bland–Altman plots showed significant negative slopes of − 0.40 in patients with AS and − 0.74 in control subjects.

Conclusions

Our data suggested that QGS was a useful method for assessing left ventricular volumes and function even in patients with AS. Cardiologists should recognize its specific characteristics.

IL-18 level in patients undergoing coronary artery bypass grafting surgery or valve replacement: which link with epicardial fat depot?

Interleukin-18 (IL-18) is a member of the interleukin-1 family of cytokines produced constitutively by different cell types and by adipose tissue. Due to the link between obesity, inflammation and cardiovascular diseases, we aimed to measure IL-18 circulating level in patients undergoing open-heart surgery both for elective coronary artery bypass grafting (CABG) or for valve replacement (VR), and we also evaluated whether epicardial adipose tissue (EAT) depot may be a potential source of IL-18. Circulating IL-18 protein was quantified by enzyme-linked immunosorbent assay. IL-18, IL-18 receptor 1 (IL-18 R1) and IL-18 receptor accessory protein (IL-18-RAP) gene expression in EAT depot were evaluated by one colour microarray platform. EAT thickness was measured by echocardiography. In this study we found that all cardiovascular patients (CABG and VR) have increased circulating IL-18 level compared to healthy control subjects (p &#60; 0.0001), but no statistical significant difference was observed between CABG and VR groups (p = 0.35). A great increase in the gene expression of IL-18 (p &#60; 0.05), IL-18 R1 (p &#60; 0.01) and IL-18 RAP (p &#60; 0.001) was observed in EAT samples obtained from CABG vs VR patients. In conclusion, CABG and VR patients had similar increased level of circulating IL-18 protein, but in EAT depots isolated from CABG gene expression of IL-18, IL-18 R1 and IL-18-RAP resulted higher than in VR patients. Future investigation on local IL-18 protein production, its autocrine-paracrine effect and its correlation with plasmatic IL-18 level could give more information on the relationship between IL-18 and coronary artery disease.

Critical care management of patients following transcatheter aortic valve replacement

Transcatheter aortic valve replacement (TAVR) is rapidly gaining popularity as a technique to surgically manage aortic stenosis (AS) in high risk patients. TAVR is significantly less invasive than the traditional approach to aortic valve replacement via median sternotomy. Patients undergoing TAVR often suffer from multiple comorbidities, and their postoperative course may be complicated by a unique set of complications that may become evident in the intensive care unit (ICU). In this article, we review the common complications of TAVR that may be observed in the ICU, and different strategies for their management.

Aortic stenosis and mitral regurgitation as predictors of atrial fibrillation during 11 years of follow-up

Background

There is limited information about any association between the onset of atrial fibrillation (AF) and the presence of valvular disease.

Methods

We retrospectively examined 940 patients in sinus rhythm, examined by echocardiography in 1996. During 11 years of follow-up, we assessed the incidence of AF and outcome defined as valvular surgery or death, in relation to baseline valvular function. AS (aortic stenosis) severity at baseline examination was assessed using peak transaortic valve pressure gradient.

Results

In univariate analysis, the risk of developing AF was related to AS (significant AS versus no significant AS; hazard ratio (HR) 3.73, 95% confidence interval (CI) 2.39-5.61, p<0.0001) and mitral regurgitation (MR) (significant MR versus no significant MR; HR 2.52, 95% CI 1.77-3.51, p<0.0001). Also the risk of valvular surgery or death was related to AS (HR 3.90, 95% CI 3.09-4.88, p<0.0001) and MR (HR 2.07, 95% CI 1.67-2.53, p<0.0001). In multivariate analyses, adjusting for sex, age, other valvular abnormalities, left ventricular ejection fraction and left atrial size − AS was independently related to both endpoints, whereas MR was not independently related to either endpoint.

Conclusions

AS, but not MR, was independently predictive of development of AF and combined valvular surgery or death. In patients with combined AS and MR, the grade of AS, more than the grade of MR, determined the risk of AF and combination of valvular surgery or death. Further studies using contemporary echocardiographic quantification of aortic stenosis are warranted to confirm these retrospective data based on peak transaortic valve pressure gradient.

Association of myocardial deformation with outcome in asymptomatic aortic stenosis with normal ejection fraction

BACKGROUND

Current guidelines recommend intervention for symptomatic aortic stenosis, but the management of asymptomatic aortic stenosis remains controversial. As left ventricular global longitudinal strain (GLS) has been shown to predict cardiovascular outcome, we sought to find whether its use could guide the assessment of risk in these patients.

METHODS AND RESULTS

We prospectively followed 79 patients with severe asymptomatic aortic stenosis (39 men; mean age, 77 ± 12 years; aortic valve [AV] area index, 0.36 cm(2)/m(2)). In addition to standard echocardiography, speckle strain was measured to assess GLS. Patients were followed for cardiac death and AV replacement driven by symptom development. A multivariable Cox regression was performed to identify associations with events. During 23 ± 20 months, 3 patients had cardiac death and 49 underwent AV replacement. Event-free survival was 72 ± 5% at 1 year, 50 ± 5% at 2 years, and 24 ± 5% at 4 years. Death and AV replacement were predicted by GLS (hazard ratio [HR], 1.14 [95% CI, 1.01-1.28]; P=0.037), as well as extent of AV calcification (HR, 2.44 [95% CI, 1.17-5.12]; P=0.018), peak transaortic pressure gradient (HR, 1.03 [95% CI, 1.01-1.04]; P<0.001), valvulo-arterial impedance (HR, 1.32 [95% CI, 1.04-1.67]; P=0.045), and Society of Thoracic Surgeons Predicted Risk of Morbidity and Mortality (HR, 0.95 [95% CI, 0.90-1.00]; P=0.052). A mean absolute GLS <15% was associated with a significant excess mortality, and this measurement added incremental prognostic value to the Society of Thoracic Surgeons Predicted Risk of Morbidity and Mortality, transaortic peak pressure gradient, AV calcification, and valvulo-arterial impedance.

CONCLUSIONS

GLS is associated with outcomes in patients with severe asymptomatic aortic stenosis, incremental to other clinical and echocardiographic variables.

Longitudinal left ventricular 2D strain is superior to ejection fraction in predicting myocardial recovery and symptomatic improvement after aortic valve implantation

BACKGROUND

Predicting improvement of myocardial function after transcatheter aortic valve implantation (TAVI) for aortic stenosis (AS) remains a challenge. As ejection fraction (EF) may be of limited value in detecting early myocardial dysfunction and predicting outcome, we assessed the potential of echocardiographic longitudinal function in this setting.

MATERIALS AND METHODS

Left ventricular (LV) function was assessed using EF, mitral annular plane systolic excursion (MAPSE), peak longitudinal 2D strain (LS) and strain rate (SR) in101consecutive patients with severe symptomatic AS (age 81 ± 11 years) undergoing TAVI. Echocardiography and assessment of clinical status including NYHA functional class were performed prior and after intervention (median 70 days).

RESULTS

Pre-interventional EF was 57 ± 17% and 32 patients (32%) had an EF<50% while 58 patients (57%) were found to have an impaired LS. After TAVI there was no significant change in EF. In contrast, LS, SR and MAPSE improved significantly (-14.0 ± 4.4 vs. -15.5 ± 4.0%; p=0.007, 0.68 ± 0.24 vs. 0.78 ± 0.23/s, p=0.002; and 9.1 ± 3.2 vs. 10.2 ± 3.3mm, p=0.006, respectively). Receiver Operating Curve characteristic analysis identified a pre-TAVI LS>-13.3% as the optimal cut-off value for predicting lack of LS recovery post TAVI. There was a marked improvement in NYHA FC after intervention (p=0.0002). Among the studied echocardiographic parameters LS change correlated closest with NYHA class improvement (r=0.42, p=0.0008).

CONCLUSION

Overall, LS appears to be more sensitive for detecting early myocardial damage in patients with AS compared to conventional echocardiographic parameters. More importantly, pre-interventional LS may identify irreversible myocardial dysfunction and LS improvement correlates with symptomatic improvement after intervention.

Preliminary feasibility and hemodynamic performance of a newly-developed self-expanding bioprosthesis and 16-F delivery system in transcatheter aortic valve implantation in sheep

We sought to evaluate the feasibility and hemodynamic performance of a new self-expanding bioprosthesis and 16-F delivery system in sheep. A 23-mm new self-expanding aortic bioprosthesis was implanted in sheep (n = 10) with a 16-F catheter via the right common carotid artery. Each sheep underwent angiography and coronary angiography before intervention, immediately and 1 h after stent implantation. Electrocardiographic monitoring was carried out during and 2 h after the procedure. Transthoracic echocardiography was employed to detect hemodynamic performance before intervention, immediately and 1 and 2 h after stent implantation. All sheep were euthanized 2 h after successful implantation for macroscopic inspection. In all cases, the new self-expanding aortic bioprosthesis was successfully delivered to the aortic root and released with a 16-F catheter. Successful implantation was achieved in 8 of 10 sheep. Hemodynamic performance and device position of successful implantation were stable 2 h after device deployment. Atrioventricular block was not observed. We conclude that it is feasible to implant the new self-expanding aortic valve with a 16-F delivery system into sheep hearts via the retrograde route.

The role of echocardiography in the evaluation and management of aortic stenosis in the older adult

Aortic stenosis is currently the most predominant valvular pathology in older adults. Signs and symptoms of aortic stenosis in this age-group may be difficult to recognize due to the decreased activity associated with aging and attribution of symptoms to other conditions. Echocardiography can be very helpful in the assessment of valvular structure and real time hemodynamic evaluation as well as in the progression of the disease over time. Unprecedented advances in echocardiography, including real time three-dimensional echocardiography, facilitate a comprehensive assessment of this condition and help in the decision-making process. Recent innovations in the percutaneous treatment of valvular diseases promise a revolution in the treatment of aortic stenosis especially in older adults.

Three years' experience of focused cardiovascular ultrasound in the peri-operative period

Ultrasound applications in peri-operative medicine have become common place in modern anaesthesia practice. Anaesthetists have performed transoesophageal echocardiography in cardiac and selected non-cardiac surgery for over two decades. We aimed to assess the indications, impact on clinical management and accuracy of focused cardiovascular ultrasound performed by anaesthetists in the peri-operative period. One hundred and seventy patients over a 3-year period had a focused transthoracic echocardiogram. Adequate images to answer the clinical question were obtained in 167 out of 170 patients (98%). The undifferentiated systolic murmur was the commonest indication (98 out of 170, 58%). Some degree of aortic stenosis was present in 47 out of 170 (26%) of patients; mitral valve disease (30 out of 170 (18%)) and pulmonary hypertension (25 out of 170 (14%)) were also common. Changes in peri-operative management occurred in 140 out of 170 (82%) patients and major findings correlated with a formal cardiology transthoracic echocardiogram in 52 out of 57 (92%) patients. Focused cardiovascular ultrasound performed by anaesthetists in the peri-operative period accurately detects major cardiac pathology and significantly alters peri-operative management.

Does aortic valve replacement mitigate the risk of preoperative heart failure?

Congestive heart failure complicating aortic valve disease has been reported to increase the operative mortality associated with aortic valve replacement. To determine whether this adverse effect remains late after aortic valve replacement, we analyzed prospectively collected and survival data of 849 patients who underwent aortic valve replacement between 1999 and 2008. There were 243 (29%) cases of heart failure preoperatively (138 current and 105 prior). Both operative and late mortality rates (up to 10 years) were significantly higher in heart failure patients. Current congestive heart failure caused a 3-fold increase in operative mortality and an 86% increase in late mortality, whereas previous history of heart failure caused a doubling of late mortality. Preoperative heart failure still compromises early and late survival after aortic valve replacement. Surgery should be considered early in patients with aortic valve disease and deferred, when possible, in those with frank heart failure.

Undercarboxylated matrix Gla protein is associated with indices of heart failure and mortality in symptomatic aortic stenosis

OBJECTIVE

Matrix Gla protein (MGP) is a calcification inhibitor and alterations in circulating MGP have been observed in different populations characterized by vascular calcification. We hypothesized that patients with calcific valvular aortic stenosis (AS) would have dysregulated circulating MGP levels.

DESIGN AND SUBJECTS

We examined plasma levels of nonphosphorylated carboxylated and undercarboxylated MGP (dp-cMGP and dp-ucMGP, respectively) in 147 patients with symptomatic severe AS and in matched healthy controls.

MAIN OUTCOME MEASURES

We further investigated the relationship between MGP levels and aortic pressure gradients and valve area by echocardiography and measures of heart failure. Finally, we assessed the prognostic value of elevated plasma dp-ucMGP level in relation to all-cause mortality in patients with AS.

RESULTS

We found markedly enhanced plasma levels of dp-cMGP and in particular of dp-ucMGP in patients with symptomatic AS. Although only weak correlations were found with the degree of AS, circulating dp-ucMGP was associated with cardiac function and long-term mortality in multivariate analysis.

CONCLUSIONS

A dysregulated MGP system may have a role in the development of left ventricular dysfunction in patients with symptomatic AS.

Assessment of myocardial mechanics using speckle tracking echocardiography: fundamentals and clinical applications

The authors summarize the recent developments in speckle-tracking echocardiography (STE), a relatively new technique that can be used in conjunction with two-dimensional or three-dimensional echocardiography for resolving the multidirectional components of left ventricular (LV) deformation. The tracking system is based on grayscale B-mode images and is obtained by automatic measurement of the distance between 2 pixels of an LV segment during the cardiac cycle, independent of the angle of insonation. The integration of STE with real-time cardiac ultrasound imaging overcomes some of the limitations of previous work in the field and has the potential to provide a unified framework to more accurately quantify the regional and global function of the left ventricle. STE holds promise to reduce interobserver and intraobserver variability in assessing regional LV function and to improve patient care while reducing health care costs through the early identification of subclinical disease. Following a brief overview of the approach, the authors pool the initial observations from clinical studies on the development, validation, merits, and limitations of STE.

Reasons for nonadherence to guidelines for aortic valve replacement in patients with severe aortic stenosis and potential solutions

The official guidelines for the treatment of patients with valvular heart disease have given a class I indication for aortic valve replacement in patients with symptomatic, severe aortic stenosis (AS). However, many patients with symptomatic, severe AS do not undergo AVR. We sought to determine the proportion and characteristics of patients with severe AS who do not undergo AVR in a university hospital and to identify the reasons for the lack of surgical referrals, despite the class I guideline indications. We retrospectively studied consecutive patients from an academic hospital with severe AS, as determined by echocardiographic criteria. The records were reviewed for clinical presentation, co-morbidities, surgical intervention, and outcomes. Of the 106 patients with severe AS, 33 (31%) had undergone AVR and 73 (69%) had not. Of those patients without AVR, 31 (42%) were symptomatic. The most common reason the patients with symptomatic, severe AS did not undergo AVR was their symptoms were thought to be unrelated to AS. Of the 42 patients (58%) who were deemed asymptomatic, only 4% had undergone exercise stress testing. With an average follow-up of 15 months, 15 (14%) of the 73 patients who did not undergo AVR died. In patients with severe AS, physicians commonly underrecognize symptoms and overestimate the operative risk. The exercise stress tests were underused in determining which patients with severe AS were symptomatic. As a result, many patients with a class I indication for AVR, who would benefit from this life-saving intervention, do not receive it.

Early surgery versus conventional treatment in asymptomatic very severe aortic stenosis

BACKGROUND

The optimal timing of surgical intervention remains controversial in asymptomatic patients with very severe aortic stenosis. We therefore compared the long-term results of early surgery and a conventional treatment strategy.

METHODS AND RESULTS

From 1996 to 2006, we prospectively included a total of 197 consecutive asymptomatic patients (99 men; age, 63+/-12 years) with very severe aortic stenosis. Patients were excluded if they had angina, syncope, exertional dyspnea, ejection fraction <0.50, significant mitral valve disease, or age >85 years. Very severe aortic stenosis was defined as a critical stenosis in the aortic valve area < or =0.75 cm(2) accompanied by a peak aortic jet velocity > or =4.5 m/s or a mean transaortic pressure gradient > or =50 mm Hg on Doppler echocardiography. The primary end point was defined as the composite of operative mortality and cardiac death during follow-up. Early surgery was performed on 102 patients, and a conventional treatment strategy was used for 95 patients. There were no significant differences between the 2 groups in terms of age, gender, European System for Cardiac Operative Risk Evaluation score, or ejection fraction. During a median follow-up of 1501 days, the operated group had no operative mortalities, no cardiac deaths, and 3 noncardiac deaths; the conventional treatment group had 18 cardiac and 10 noncardiac deaths. The estimated actuarial 6-year cardiac and all-cause mortality rates were 0% and 2+/-1% in the operated group and 24+/-5% and 32+/-6% in the conventional treatment group, respectively (P<0.001), and for 57 propensity score-matched pairs, the risk of all-cause mortality was significantly lower in the operated group than in the conventional treatment group (hazard ratio, 0.135; 95% confidence interval, 0.030 to 0.597; P=0.008).

CONCLUSIONS

Compared with the conventional treatment strategy, early surgery in patients with very severe aortic stenosis is associated with an improved long-term survival by decreasing cardiac mortality. Early surgery is therefore a therapeutic option to further improve clinical outcomes in asymptomatic patients with very severe aortic stenosis and low operative risk.

Meta-analysis of prognostic value of stress testing in patients with asymptomatic severe aortic stenosis

The management strategy in asymptomatic patients with severe aortic stenosis (AS) is controversial. Aortic valve replacement has significant morbidity and mortality, while there is a risk for sudden cardiac death with conservative management. There is no consensus on the prognostic value of stress testing to stratify management. A pooled analysis of studies in patients with severe AS was performed to assess the prognostic value of stress testing for adverse events, including angina, dyspnea, acute heart failure, sudden death, and symptoms requiring aortic valve replacement. A search of published research was performed using the terms "stress test" and "asymptomatic aortic stenosis." A random-effects model was used to calculate pooled odds ratios and 95% confidence intervals. Data from 7 studies were included (491 patients with asymptomatic severe AS). None of the patients experienced any complications during or after stress testing. There were no sudden deaths in the patients with normal stress test results after 1 year of follow-up, while 5% with abnormal stress test results had sudden cardiac death. Overall, 52 of 253 patients (21%) with normal stress test results had adverse cardiac events, compared with 156 of 238 (66%) with abnormal stress test results (odds ratio 0.12, 95% confidence interval 0.07 to 0.21, p <0.001). In conclusion, stress testing in asymptomatic patients with severe AS is safe and identifies patients at risk for adverse cardiac events and sudden cardiac death. These data suggest that stress tests can be used for risk stratification and for deciding on the timing of aortic valve replacement in asymptomatic patients with severe AS.

Noninvasive imaging of the heart and coronary arteries

There are multiple imaging modalities currently available to noninvasively evaluate the heart and coronary arteries. Choosing the most appropriate modality depends on the pertinent clinical question and the underlying patient characteristics. This article provides an overview of the fields of echocardiography, myocardial perfusion imaging, cardiac computed tomography, and cardiac magnetic resonance imaging, with particular attention to specific clinical applications for cardiac surgery patients.

Increased interleukin-18 expression in nonrheumatic aortic valve stenosis

BACKGROUND

It is unknown whether interleukin-18 (IL-18) participates in the pathophysiology of nonrheumatic aortic stenosis (NR-AS).

METHODS

We examined IL-18 expression in human NR-AS valves by immunohistochemistry and Western blot analysis.

RESULTS

Immunohistochemistry revealed that NR-AS valves showed increased IL-18 expression compared with controls. IL-18 receptor was also expressed in NR-AS valves. Western blot analysis showed that IL-18 was expressed as an active form in NR-AS valves. Furthermore, increased IL-18 expression was correlated with the advanced clinical severity of NR-AS.

CONCLUSIONS

IL-18 was expressed in the aortic valves and up-regulated in NR-AS valves. IL-18 may contribute to the pathophysiology of NR-AS.

Valvular regurgitation and stenosis: when is surgery required?

Valvular heart disease is a growing public health problem, with an increasing prevalence due to an ageing population. Despite advances, the medical management of symptomatic valvular heart diseases remains suboptimal, necessitating surgical correction. The challenge remains in identifying an asymptomatic or mildly symptomatic patient who will benefit from timely surgery before irreversible changes in cardiac function have occurred. The potential risks of surgery versus watchful expectancy require careful decision-making. This review is a focused update on the existing guidelines and identifies the knowledge gaps and avenues of future research in the management of patients with valvular heart diseases.