Aortic regurgitation severity after transcatheter aortic valve implantation is underestimated by echocardiography compared with MRI.

OBJECTIVE: Aortic regurgitation (AR) after transcatheter aortic valve implantation (TAVI) is associated with a poor clinical outcome and its assessment therefore crucial. Quantification of AR by transthoracic echocardiography (TTE), however, remains challenging in this setting. The present study used quantitative flow measurement by cardiac MRI (CMR) with calculation of regurgitant fraction (RF) for the assessment of AR and compared the results with TTE. METHODS AND RESULTS: We included 65 patients with a mean age of 82.2±8.1 years (38 women) who underwent successful TAVI with Edwards SAPIEN valves (52 transfemoral, 13 transapical). The post-interventional degree of AR was assessed by CMR and by TTE. There was agreement between CMR and TTE with regards to the absence of severe AR. However, TTE significantly underestimated the presence of moderate AR classifying it to be mild in 38 and moderate in only 5 patients, whereas CMR found mild AR in 23 and moderate in 16 patients. Overall, there was only fair agreement between CMR and TTE regarding the grading of AR with a weighted κ of 0.33. The rate of detection of TTE for more than mild AR was only 19%. CONCLUSIONS: Using CMR for the quantification of AR in a sizeable group of TAVI patients, we demonstrate a strong tendency of TTE to underestimate AR compared with CMR. Since higher AR severity on echocardiography has been associated with worse patient outcome, the potential incremental prognostic value of CMR should be studied prospectively in this setting.

Low flow, low gradient severe aortic stenosis: diagnosis, treatment and prognosis.

Low flow, low gradient aortic stenosis is a highly challenging condition in terms of diagnosis and therapeutic management. With regard to prognosis and to management decisions, it is essential to distinguish those patients with preserved systolic left ventricular ejection fraction from patients with impaired systolic left ventricular ejection fraction, and in particular those with true severe aortic stenosis from patients who have non-significant aortic stenosis associated with reduced transvalvular flow for other reasons and who present with a functionally small valve area. In addition, measurement errors deserve particular consideration in order to avoid a misdiagnosis. Echocardiography, including low dose dobutamine stress studies, is the key diagnostic tool. Magnetic resonance imaging, invasive assessment of haemodynamics by catheterisation and quantification of valve calcification by computed tomography calcium scoring can provide additional information that helps to assess aortic stenosis severity accurately, predict outcome and guide treatment decisions. Percutaneous aortic valve implantation may provide an intervention with lower periprocedural risk in this challenging patient subset; however, further studies are required to define its exact role in this setting.

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.

Impact of transcatheter aortic valve implantation or surgical aortic valve replacement on right ventricular function.

OBJECTIVE: Transcatheter aortic valve implantation (TAVI) has become an alternative to surgical aortic valve replacement (sAVR) in selected high risk patients. While improvement in left ventricular function after TAVI has been demonstrated, little is known about the impact on right ventricular (RV) function. Since postoperative RV dysfunction is linked to adverse outcomes, the authors sought to investigate the effect of TAVI and aortic valve replacement (AVR) on RV function using speckle tracking echocardiography. DESIGN: Cross-sectional study in tertiary healthcare setting. SETTING: 101 patients with severe symptomatic aortic stenosis (age 81 ± 11 yrs) who underwent TAVI and 22 patients who underwent sAVR were included. RV function was assessed using 2D longitudinal strain (RV-LS), fractional area change and tricuspid annular plain systolic excursion before and after sAVR and TAVI (median 89 days). RESULTS: Although the TAVI group had worse baseline characteristics, RV function remained unchanged in this group whereas significant deterioration of RV function was observed in patients undergoing conventional AVR: RV-LS (-25.2 ± 6.1 vs -20.0 ± 7.0%; p=0.009), RV-fractional area change (47.0 ± 7.0 vs 39.8 ± 10.7%, p=0.019) and tricuspid annular plain systolic excursion (24 ± 5 vs 16 ± 4 mm, p=0.0001). CONCLUSION: While TAVI did not affect RV function it deteriorated significantly in patients undergoing sAVR. The authors speculate that this may be related to the detrimental effects of pericardiotomy and, to a lesser degree, cardiopulmonary bypass. While further studies are required to assess the clinical significance of this finding, these data suggest that patients with pre-existing RV dysfunction may benefit from TAVI and that RV function should be incorporated into future risk scores.

Right ventricular-left ventricular interaction in adults with Tetralogy of Fallot: a combined cardiac magnetic resonance and echocardiographic speckle tracking study.

OBJECTIVES: To assess ventricular dysfunction and ventricular interaction after repair of Tetralogy of Fallot (ToF) employing echocardiography speckle-tracking and cardiac magnetic resonance imaging (CMR). BACKGROUND: Severe pulmonary regurgitation and right ventricular (RV) dysfunction are common after repair of ToF and may also affect the shape and function of the left ventricle (LV). Recent studies suggest that LV dysfunction may be of particular prognostic value. METHODS AND RESULTS: Twenty-one consecutive adults with repaired ToF (15 male, mean age 38 ± 11 years, 7 with severe PR) underwent a comprehensive echocardiographic exam including speckle-tracking analysis, CMR and cardiopulmonary exercise testing. Twenty-one subjects without relevant heart disease served as controls. Echocardiographically measured RV diameters correlated with RV volumes obtained from CMR (r=0.63; p=0.006). In addition, a close correlation was found between RV and LV function on CMR (r=0.74, p=0.002), speckle-tracking LV and RV peak longitudinal 2D strain (r=0.66, p=0.003) and mitral and tricuspid annular plain systolic excursion (r=0.71, p=0.0003). While LV ejection fraction was normal in the majority of patients and not different from controls, LV longitudinal strain was significantly reduced in ToF patients (-16.5 ± 3.3 vs. -20.5 ± 2.7%, p=0.0001). CONCLUSION: Left and right ventricular function both by CMR and speckle-tracking is interrelated in adults with repaired ToF. Despite normal LV ejection fraction, 2D longitudinal strain is significantly reduced in ToF patients, suggesting subclinical LV myocardial damage. Considering the potential prognostic value of LV dysfunction in ToF, this measurement may gain importance and should be included in future outcome studies.

The risk of acute kidney injury and its impact on 30-day and long-term mortality after transcatheter aortic valve implantation.

Background. Transcatheter aortic valve implantation (TAVI) is widely used in high risk patients (pts) with aortic stenosis. Underlying chronic kidney disease implicates a high risk of postprocedural acute kidney injury (AKI). We analyzed its occurrence, impact on hospital stay, and mortality. Methods. 150 consecutive pts underwent TAVI in our institution (mean age 81 ± 7 years; logistic EuroSCORE 24 ± 15%). AKI definition was a creatinine rise of 26.5 µmol/L or more within 48 hours postprocedural. Ten patients on chronic hemodialysis were excluded. Results. AKI occurred in 28 pts (20%). Baseline creatinine was higher in AKI pts (126.4 ± 59.2 µmol/L versus 108.7 ± 45.1 µmol/L, P = 0.09). Contrast media use was distributed evenly. Both, 30-day mortality (29% versus 7%, P < 0.0001) and long-term mortality (43% versus 18%, P < 0.0001) were higher; hospital stay was longer in AKI pts (20 ± 12 versus 15 ± 10 days, P = 0.03). Predicted renal failure calculated STS Score was similar (8.0 ± 5.0% [AKI] versus 7.1 ± 4.0% [non-AKI], P = 0.32) and estimated lower renal failure rates than observed. Conclusion. AKI remains a frequent complication with increased mortality in TAVI pts. Careful identification of risk factors and development of more suitable risk scores are essential.

Imaging decision-making for transfemoral or transapical approach of transcatheter aortic valve implantation.

Transcatheter aortic valve implantation has been shown to be a feasible alternative to surgical aortic valve replacement in selected high-risk patients. Although, being less invasive, catheter techniques remain associated with the potential of serious complications. Procedural success and avoidance of such complications critically depends on careful patient selection and comprehensive preprocedural evaluation of vascular access, cardiac and aortic root anatomy. This article reviews the role of currently available imaging modalities for appropriate patient selection and decision between transfemoral and transapical approach.