Changes in myocardial deformation after transcatheter and surgical aortic valve replacement

Potential Diagnostic and Prognostic Values of Left Atrial Strain in Valvular Heart Disease

There has been increasing evidence supporting the importance of left atrial (LA) functional analysis and measurement in various physiologic and pathologic cardiovascular conditions due to its high diagnostic and prognostic values. Assessment of LA strain (LAS) has emerged as an early marker of subclinical LA dysfunction. Using speckle-tracking echocardiography, LAS can be measured in all phases of LA function (reservoir, conduit, and booster pump). In valvular heart disease (VHD), surgical and nonsurgical interventions should be performed before irreversible left ventricular (LV) and/or LA myocardial dysfunction. The current guidelines recommended using LV strain as a parameter for early detection and timely intervention. Currently, many published data have shown the diagnostic and prognostic values of LAS in VHD, which is encouraging to integrate LAS during echo assessment. In this review, we aim to collect the current data about the clinical utility of LAS changes in risk stratification, predicting outcome, and guiding the time of intervention in VHD. The review summarized these data according to the type of valve pathologies.

Atrial electrical remodeling and function after transcatheter aortic valve replacement in patients with aortic stenosis

To examine reverse atrial electrical remodeling in patients with aortic stenosis (AS) after trans-catheter aortic valve replacement (TAVR). In 65 consecutive patients with severe AS (83 ± 4 years, 47 (72.3%) females), we analyzed ECG records for the P wave duration (PWD) in lead II and P-terminal force (PTFV1) in V1, and measured cardiac dimensions and function by echocardiography (ECHO) following TAVR. Biomarkers were measured to assess myocardial injury by TAVR. TAVR was successfully performed without major complications: the aortic valve area increased from 0.62 ± 0.14 cm2 to 1.52 ± 0.24cm2, and the trans-aortic pressure gradient decreased from 58.4 ± 15.9 mmHg to 15.0 ± 19.6 mmHg. PWD and PTFV increased immediately after TAVR and returned to the pre-TAVR levels on the next day. Then, the PWD declined toward 6 months after TAVR non-significantly in all patients, but significantly in 25 patients with baseline PWD ≥ 130 ms (P = 0.039). PTFV1 showed no long-term change. Improvement was observed in the ejection fraction, all thickness of the left ventricle and in the left atrial dimensions on ECHO. After recovery from transient aggravation by TAVR procedure, PWD reversed slowly, and the change was significant in those with baseline PWD ≥ 130 ms while change in PTFV1 was not significant at 6 months of follow-up. ECHO showed a reversal of remodeling in the left ventricle and in the left atrial dimension after TAVR.

Left Atrial Remodeling in Response to Aortic Valve Replacement: Pathophysiology and Myocardial Strain Analysis

Severe aortic stenosis (AS) is the most common valve disease in the elderly and is associated with poor prognosis if treated only medically. AS causes chronic pressure overload, concentric left ventricular (LV) hypertrophy, myocardial stiffness, and diastolic dysfunction. This adverse remodeling also affects the left atrium (LA), which dilates and develops myocardial fibrosis, with a reduction in intrinsic function and a consequent high risk of the development of atrial fibrillation. Speckle-tracking echocardiography is able to detect myocardial dysfunction before other conventional parameters, such as LV ejection fraction, and also predict clinical outcomes. This review aims at describing LV and LA remodeling in AS and before and after aortic valve replacement and the usefulness of myocardial strain analysis in this clinical setting.

Investigation on Imaging Features and Clinical Significance of Cardiac CT in Comprehensive Evaluation of Aortic Valve and Root before Percutaneous Aortic Valve Replacement

Medical imaging feature analysis is the basis of medical image processing and analysis. The solution of this problem not only directly affects the successful application of computer graphics and image technology in medicine but also has important theoretical and practical significance. In this paper, the imaging characteristics and clinical significance are discussed by studying the comprehensive evaluation of aortic valve and root before aortic valve replacement. In recent years, preoperative comprehensive evaluation of the aortic valve and root has been gradually carried out. Compared with traditional methods, minimally invasive surgery brings more accurate diagnosis to patients, quick recovery and discharge after surgery, and less pain. This study retrospectively includes patients with severe aortic stenosis who underwent TAVR with routine computed tomography. Based on CT images, the determination and grouping of bicuspid aortic valve and tricuspid aortic valve were completed. Thirteen cross-sectional levels of the aorta-iliac-femoral vascular access were completed. The results showed that 3 people had stroke (17.6%) and 5 people had myocardial infarction (29.4%) during the follow-up period. Atrial fibrillation occurred in 5 patients (29.4%), permanent pacemaker implantation was performed in 1 patient (5.9%), and acute kidney injury occurred in 7 patients (41.2%). No patient died due to surgery-related causes, and the analysis of imaging features and clinical significance in the preoperative comprehensive evaluation of the aortic valve and root played a crucial role. In the training stage, the principal component analysis method was used to train the shape, and the model of the shape intensity of the aortic valve and the shape change of each principal component was obtained. The most probable aortic valve region in the target image was obtained by matching the similarity of all atlases, and the correct aortic valve segmentation was obtained by using the first level set of shape intensity. The experimental part verified the accuracy of the algorithm.

The Central Role of Left Atrium in Heart Failure

In past cardiovascular medicine, the attention to the left ventricle-identified as the only indicator and determinant of healthy or unhealthy cardiac conditions- has systematically hidden the role of the left atrium (LA). The recent advances in cardiovascular imaging have provided a better understanding of LA anatomy, physiology, and pathology, making us realize that this functional structure is far from being an innocent spectator. We now know that the LA's mechanical and neuro-hormonal properties play a relevant part in several cardiovascular diseases, including atrial fibrillation, ischemic heart disease, valvular heart disease, and heart failure. The present review aims to describe the role of LA in the specific setting of heart failure. We provide currently available information on LA structure and function and summarize its role as a determinant of symptoms, prognosis, and potential therapeutic target in heart failure patients.

Left Ventricular Strain Normalizes After Balloon Aortic Valvuloplasty in Infants with Congenital Aortic Stenosis

Severe aortic stenosis (AS) causes left ventricular (LV) afterload and subendocardial ischemia. Despite this, most infants with AS have normal LV ejection fraction (EF). Strain analysis using two-dimensional speckle tracking echocardiography (2DSTE) may identify more sensitive markers of systolic dysfunction. We sought to show changes in LV strain after balloon aortic valvuloplasty (BAV) in infants with AS. Twenty-seven infants ≤ 1 year of age with AS who underwent BAV from 2007 to 2017 were included. Echocardiograms before/after BAV were retrospectively analyzed with 2DSTE. Median age was 29 days (interquartile range 3-52) and LV EF was 64 ± 10%. Global longitudinal strain (GLS) significantly improved post-BAV (- 17 ± 5 vs. - 20 ± 4%, p = 0.001) with no difference in global circumferential strain. Peak longitudinal strain was abnormal at the inferoseptal base and mid-ventricle (- 15 ± 6 and - 17 ± 5 = 7%, respectively) and significantly improved in the basal and mid-anterolateral segments (- 17 ± 5 vs. - 21 ± 5%, p < 0.01; - 17 ± 6% vs. - 20 ± 5%, p = 0.01, respectively). Five (20%) patients underwent reintervention, and had significantly higher peak-to-peak pre and post-BAV AS gradients (86 ± 14 vs. 61 ± 20 mmHg, p = 0.02; 33 ± 17 vs. 21 ± 10 mmHg, p = 0.04, respectively). In conclusion, longitudinal strain is abnormal in infants with AS and improves to previously published normal values after BAV.

Effectiveness and Safety of Transcatheter Aortic Valve Implantation in Patients With Aortic Stenosis and Variable Ejection Fractions (<40%, 40%-49%, and >50%)

We evaluated the safety and efficacy of transcatheter aortic valve implantation (TAVI) in aortic stenosis patients with mid-range ejection fraction (ASmrEF) and compared it to aortic stenosis patients with reduced ejection fraction (ASrEF) and preserved ejection fraction (ASpEF). TAVI cases were stratified by baseline ejection fraction (ASrEF, ASmrEF, ASpEF) and compared for characteristics, procedural outcomes, and change in echocardiographic parameters at 1 year and mortality over a 5-year follow-up. The final study population included 708 patients who underwent TAVI. ASmrEF patients presented with improved EF at 1-year after procedure (49.0 ± 9.8 at 1 year vs 43.0 ± 2.5 at baseline, p <0.001) and showed improvements in left ventricular (LV) diameters (LV end-diastolic diameter: 50.4 ± 6.0 at 1 year vs 53.0 ± 5.5 at baseline and LV end-systolic diameter 34.7 ± 7.8 at 1 year vs 39.5 ± 5.9 at baseline, p <0.001 for both). LVEF improved for patients with ASrEF but not in ASpEF patients. LV diameters did not improve for patients in either group. Procedural safety and success rates were similar between all heart failure groups. Survival rates over a 5-year follow-up post-TAVI were not different between patients with ASmrEF, ASrEF, and ASpEF (ASrEF 78.4%, ASmrEF 81.9%, ASpEF 78.3%, p = 0.327). TAVI for patients with ASmrEF is safe and effective and results in marked improvement of LV function and structure.

Changes in dynamic left ventricular function, assessed by the strain-volume loop, relate to reverse remodeling after aortic valve replacement

Aortic valve replacement (AVR) leads to remodeling of the left ventricle (LV). Adopting a novel technique to examine dynamic LV function, our study explored whether post-AVR changes in dynamic LV function and/or changes in aortic valve characteristics are associated with LV mass regression during follow-up. We retrospectively analyzed 30 participants with severe aortic stenosis who underwent standard transthoracic echocardiographic assessment before AVR [88 (IQR or interquartile range: 22–143) days], post-AVR [13 (6–22) days], and during follow-up [455 (226–907) days]. We assessed standard measures of LV structure, function, and aortic valve characteristics. Novel insight into dynamic LV function was provided through a four-chamber image by examination of the temporal relation between LV longitudinal strain (ε) and volume (ε-volume loops), representing the contribution of LV mechanics to volume change. AVR resulted in immediate changes in structural valve characteristics, alongside a reduced LV longitudinal peak ε and improved coherence between the diastolic and systolic part of the ε-volume loop (all P < 0.05). Follow-up revealed a decrease in LV mass ( P < 0.05) and improvements in LV ejection fraction and LV longitudinal peak ε ( P < 0.05). A significant relationship was present between decline in LV mass during follow-up and post-AVR improvement in coherence of the ε-volume loops ( r = 0.439, P = 0.03), but not with post-AVR changes in aortic valve characteristics or LV function (all P > 0.05). We found that post-AVR improvements in dynamic LV function are related to long-term remodeling of the LV. This highlights the potential importance of assessing dynamic LV function for cardiac adaptations in vivo.

NEW & NOTEWORTHY Combining temporal measures of left ventricular longitudinal strain and volume (strain-volume loop) provides novel insights in dynamic cardiac function. In patients with aortic stenosis who underwent aortic valve replacement, postsurgical changes in the strain-volume loop are associated with regression of left ventricular mass during follow-up. This provides novel insight into the relation between postsurgery changes in cardiac hemodynamics and long-term structural remodeling, but also supports the potential utility of the assessment of dynamic cardiac function.

Regression of left ventricular hypertrophy provides an additive physiological benefit following treatment of aortic stenosis: Insights from serial coronary wave intensity analysis

AIM

Severe aortic stenosis frequently involves the development of left ventricular hypertrophy (LVH) creating a dichotomous haemodynamic state within the coronary circulation. Whilst the increased force of ventricular contraction enhances its resultant relaxation and thus increases the distal diastolic coronary "suction" force, the presence of LVH has a potentially opposing effect on ventricular-coronary interplay. The aim of this study was to use non-invasive coronary wave intensity analysis (WIA) to separate and measure the sequential effects of outflow tract obstruction relief and then LVH regression following intervention for aortic stenosis.

METHODS

Fifteen patients with unobstructed coronary arteries undergoing aortic valve intervention (11 surgical aortic valve replacement [SAVR], 4 TAVI) were successfully assessed before and after intervention, and at 6 and 12 months post-procedure. Coronary WIA was constructed from simultaneously acquired coronary flow from transthoracic echo and pressure from an oscillometric brachial cuff system.

RESULTS

Immediately following intervention, a decline in the backward decompression wave (BDW) was noted (9.7 ± 5.7 vs 5.1 ± 3.6 × 10³  W/m² /s, P < 0.01). Over 12 months, LV mass index fell from 114 ± 19 to 82 ± 17 kg/m² . Accompanying this, the BDW fraction increased to 32.8 ± 7.2% at 6 months (P = 0.01 vs post-procedure) and 34.7 ± 6.7% at 12 months (P < 0.001 vs post-procedure).

CONCLUSION

In aortic stenosis, both the outflow tract gradient and the presence of LVH impact significantly on coronary haemodynamics that cannot be appreciated by examining resting coronary flow rates alone. An immediate change in coronary wave intensity occurs following intervention with further effects appreciable with hypertrophy regression. The improvement in prognosis with treatment is likely to be attributable to both features.