Predicting left ventricular recovery after replacement of a regurgitant aortic valve in pediatric and young adult patients: is it ever too late?

Short-Term Left Ventricular Reverse Remodeling after Transcatheter Aortic Valve Replacement in Children

BACKGROUND

There are no published data on left ventricular (LV) reverse remodeling after transcatheter aortic valve replacement (TAVR) in children. The aim of this study was to assess changes in LV echocardiographic parameters 6 months after TAVR in children.

METHODS

This single-center, retrospective study included all 22 patients (age < 21 years) who underwent TAVR. The median age was 14.7 years (interquartile range, 13.3-15.9 years), median weight was 57 kg (interquartile range, 46.0-66.3 kg), and 59% of patients were male. Demographics, type and duration of aortic valve dysfunction, symptom and treatment data, and preprocedural and 6-month follow-up echocardiographic data (LV volume, mass, end-diastolic dimension, end-systolic dimension, ejection fraction [EF], sphericity, and longitudinal strain) were collected. Failure to reverse remodel at 6 months was defined as meeting at least two of the following: Z score ≥ 2 that was unchanged or increased from baseline for LV volume, mass, end-diastolic dimension, or end-systolic dimension; abnormally high sphericity index that was unchanged or increased; and abnormally low EF or longitudinal strain. Median, interquartile range, and range are reported for continuous variables, and pre- and post-TAVR data were compared using the Wilcoxon signed rank test.

RESULTS

Eight patients (36%) had isolated aortic stenosis, four (18%) had isolated regurgitation, and 10 had (46%) mixed disease. Twelve (55%) had symptoms and 20 (91%) had prior surgical or catheter valve interventions. The primary complication was left bundle branch block, occurring in four children (18%). At 6 months, LV volume, mass, end-diastolic dimension, end-systolic dimension, and sphericity index improved. EF and strain were normal at baseline and at follow-up. Of three patients who failed to reverse remodel, two had left bundle branch block. Of three patients with persistent symptoms, one had failure of reverse remodeling.

CONCLUSIONS

Most pediatric patients had evidence of reverse LV remodeling 6 months after TAVR, suggesting a possible alternative to surgical aortic valve replacement in this population. Functional parameters (EF and strain) were normal at baseline and follow-up. Future studies are needed to determine optimal timing of TAVR and to explore the association of postprocedural left bundle branch block on failed reverse remodeling and outcomes in this population.

Left ventricular systolic function impairment in children after balloon valvuloplasty for congenital aortic stenosis assessed by 2D speckle tracking echocardiography

AIMS

The aim of the study was to evaluate left ventricular (LV) remodeling and systolic function using two-dimensional speckle tracking echocardiographic (2D STE) imaging in children at a long-term (more than 36 months, 107.5±57.8 months) after balloon valvuloplasty for aortic stenosis (BAV).

METHODS AND RESULTS

40 patients (mean age 9,68 years, 75% male) after BAV and 62 control subjects matched to the age and heart rate were prospectively evaluated. The 2D STE assessment of LV longitudinal and circumferential strain and strain rate was performed. Left ventricular eccentric hypertrophy (LVEH) was diagnosed in 75% of patients in the study group. Left ventricular ejection fraction (LVEF) was normal in all patients. In study group, global longitudinal strain (GLS), global longitudinal strain rate (GLSr) were significantly lower compared with the controls: GLS (-19.7±2.22% vs. -22.3±1.5%, P< 0.001), GLSr (-0.89±0.15/s vs. -1.04 ±0.12/s, P < 0.001). Regional (basal, middle and apical segments) strain and strain rate were also lower compared with control group. Global circumferential strain (GCS), global circumferential strain rate (GCSr) as well as regional (basal, middle and apical segments) strain and strain rate were normal. Multivariable logistic regression analysis included: instantaneous peak systolic Doppler gradient across aortic valve (PGmax), grade of aortic regurgitation (AR), left ventricular mass index (LVMI), left ventricular relative wall thickness (LVRWT), left ventricular end-diastolic diameter (LVEDd), peak systolic mitral annular velocity of the septal and lateral corner (S'spt, S'lat), LVEF before BAV and time after BAV and showed that the only predictor of reduced GLS was LV eccentric hypertrophy [odds ratio 6.9; (95% CI: 1.37-12.5), P = 0.045].

CONCLUSION

Patients at long-term observation after BAV present the subclinical LV systolic impairment, which is associated with the presence of its remodeling. Longitudinal deformation is the most sensitive marker of LV systolic impairment in this group of patients.

Persistence of Reduced Left Ventricular Function after Aortic Valve Surgery for Aortic Valve Regurgitation: Bicuspid versus Tricuspid

OBJECTIVE

 Long-term prognosis of patients with aortic regurgitation (AR) and reduced left ventricular ejection fraction (LVEF) who undergo aortic valve surgery (AVS) is unknown. Due to the congenital origin, bicuspid aortic valve (BAV) morphotype might be associated with a more severe cardiomyopathy. We aimed to evaluate the LVEF recovery after aortic valve replacement (AVR) surgery in patients with AR and reduced preoperative LVEF.

METHODS

 This retrospective analysis included 1,170 consecutive patients with moderate to severe AR who underwent AVS at our institution between January 2005 and April 2016. Preoperative echocardiography revealed 154 (13%) patients with predominant AR and baseline LVEF < 50%. A total of 60 (39%) patients had a BAV (BAV group), while the remaining 94 (61%) patients had a tricuspid morphotype (tricuspid aortic valve [TAV] group). Follow-up protocol included clinical interview using a structured questionnaire and echocardiographic follow-up.

RESULTS

 A total of 154 patients (mean age 63.5 ± 12.4 years, 71% male) underwent AVS for AR in the context of reduced LVEF (mean LVEF 42 ± 8%). Fifteen (10%) patients had a severely reduced preoperative LVEF ≤ 30%. Mean STS (Society of Thoracic Surgeons) score was 1.36 ± 1.09%. Mean follow-up was comparable between both the study groups (BAV: 50 ± 40 months vs. TAV: 40 ± 38 months, p = 0.140). A total of 25 (17%) patients died during follow-up. Follow-up echocardiography demonstrated similar rate of postoperatively reduced LVEF in both groups (i.e., 39% BAV patients vs. 43% TAV patients; p = 0.638). Cox's regression analysis showed no significant impact of BAV morphotype (i.e., as compared with TAV) on the postoperative LVEF recovery (odds ratio [OR]: 1.065; p = 0.859). Severe left ventricular (LV) dysfunction at baseline (i.e., LVEF ≤ 30%) was a strong predictor for persistence of reduced LVEF during follow-up (OR: 3.174; 95% confidence interval: 1.517-6.640; p = 0.002). Survival was significantly reduced in patients with persisting LV dysfunction versus those in whom LVEF recovered (log rank: p < 0.001).

CONCLUSION

 Our study demonstrates that reduced LVEF persists postoperatively in 40 to 45% patients who present with relevant AR and reduced LVEF at baseline. Postoperative LVEF recovery is independent of aortic valve morphotype (i.e., BAV vs. TAV). Severe LV dysfunction (LVEF ≤ 30%) at baseline is a strong predictor for persistence of reduced LVEF in patients with AR and results in significantly reduced long-term survival.

Cardiomyopathy in Children: Classification and Diagnosis: A Scientific Statement From the American Heart Association

In this scientific statement from the American Heart Association, experts in the field of cardiomyopathy (heart muscle disease) in children address 2 issues: the most current understanding of the causes of cardiomyopathy in children and the optimal approaches to diagnosis cardiomyopathy in children. Cardiomyopathies result in some of the worst pediatric cardiology outcomes; nearly 40% of children who present with symptomatic cardiomyopathy undergo a heart transplantation or die within the first 2 years after diagnosis. The percentage of children with cardiomyopathy who underwent a heart transplantation has not declined over the past 10 years, and cardiomyopathy remains the leading cause of transplantation for children >1 year of age. Studies from the National Heart, Lung, and Blood Institute-funded Pediatric Cardiomyopathy Registry have shown that causes are established in very few children with cardiomyopathy, yet genetic causes are likely to be present in most. The incidence of pediatric cardiomyopathy is ≈1 per 100 000 children. This is comparable to the incidence of such childhood cancers as lymphoma, Wilms tumor, and neuroblastoma. However, the published research and scientific conferences focused on pediatric cardiomyopathy are sparcer than for those cancers. The aim of the statement is to focus on the diagnosis and classification of cardiomyopathy. We anticipate that this report will help shape the future research priorities in this set of diseases to achieve earlier diagnosis, improved clinical outcomes, and better quality of life for these children and their families.

Holodiastolic Flow Reversal at the Descending Aorta on Cardiac Magnetic Resonance is Neither Sensitive Nor Specific for Significant Aortic Regurgitation in Patients with Congenital Heart Disease

Holodiastolic flow reversal in the descending aorta on echocardiogram suggests significant aortic regurgitation. The study aim was to determine whether the presence of holodiastolic flow reversal on cardiac magnetic resonance imaging (MRI) correlates with aortic valve regurgitant fraction. We retrospectively reviewed 166 cardiac MRIs (64 % male, age 14.1 ± 9.5 years) from January 2011 to May 2012 where velocity mapping was acquired at both the aortic valve and the descending aorta at the level of the diaphragm. Descending aorta velocity maps were checked for baseline offset using a static reference region. Holodiastolic flow reversal was defined as flow reversal throughout diastole both before and after baseline correction. Significant aortic regurgitation was defined as regurgitant fraction >10 %. Aortic valve regurgitant fraction was <10 % in 144 patients (Group A), 10-20 % inclusive in 7 patients (Group B), and >20 % in 15 patients (Group C). Though the aortic valve regurgitant fraction was significantly higher for patients with holodiastolic flow reversal versus those without (8.5 ± 14.2 vs. 3.8 ± 6.6 %, p = 0.02), holodiastolic flow reversal was present in 32 Group A patients (22 %). In comparison, 4 Group B patients (57 %) and 7 Group C patients (47 %) had holodiastolic flow reversal. The sensitivity (Groups B and C) was 0.5, and the specificity (Group A) was 0.78. Holodiastolic flow reversal in the descending aorta on cardiac MRI was neither sensitive nor specific for predicting significant aortic regurgitation in this study population. Holodiastolic flow reversal in the absence of significant aortic regurgitation may be a relatively common finding in patients with congenital heart disease.

The Ross, Konno, and Ross-Konno operations for congenital left ventricular outflow tract abnormalities

Operations for left ventricular outflow tract abnormalities are centred on hemodynamic conditions that relate to subvalvar stenosis, valvar stenosis/regurgitation, aortic annular hypoplasia, and supravalvar aortic stenosis. Operative interventions over the years have evolved because the intervening outcomes proved to be unsatisfactory. The resection for subvalvar aortic stenosis has progressed from a fibrous "membrane" resection to a more extensive fibromuscular resection. Operative solutions for valvar aortic stenosis and regurgitation have resulted in operative interventions that depend on simple commissurotomy, leaflet extensions, prosthetic mechanical valve replacement, biologic valve replacement, including the pulmonary autograft, and operations to treat aortic annular stenosis. Although there are enthusiastic proponents for all of these strategies, the fact remains that none have proven to be curative; patients can expect to undergo further procedures during their lifetimes. The short- and mid-term solutions to these left ventricular outflow tract abnormalities have improved based on operations that have been attended by increasing operative complexity. The purpose of this review is to chronicle the operative steps of the Ross operation, the Konno-Rastan operation, the modified Konno operation, the Ross-Konno operation, and the modified Ross-Konno operation.

Direct measurement of aortic regurgitation with phase-contrast magnetic resonance is inaccurate: proposal of an alternative method of quantification

BACKGROUND

Phase-contrast magnetic resonance (MR) has been widely used for quantification of aortic regurgitation. However there is significant practice variability regarding where and how the blood flow data are acquired.

OBJECTIVE

To compare the accuracy of flow quantification of aortic regurgitation at three levels: the ascending aorta at the level of the right pulmonary artery (level 1), the aortic valve hinge points at end-diastole (level 2) and the aortic valve hinge points at end-systole (level 3).

MATERIALS AND METHODS

We performed cardiovascular MR in 43 children with aortic regurgitation. By using phase-contrast MR, we measured the systolic forward, diastolic retrograde and net forward flow volume indices at three levels. At each level, the following comparisons were made: (1) systolic forward flow volume index (FFVI) versus left ventricular cardiac index (LVCI) measured by cine ventricular volumetry; (2) retrograde flow volume index (RFVI) versus estimated aortic regurgitation volume index (which equals LVCI minus pulmonary blood flow index [QPI]); (3) net forward flow volume index (NFVI) versus pulmonary blood flow index.

RESULTS

The forward flow volume index, retrograde flow volume index and net forward flow volume index measured at each of the three levels were significantly different except for the retrograde flow volume index measured at levels 1 and 3. There were good correlations between the forward flow volume index and the left ventricular cardiac index at all three levels, with measurement at level 2 showing the best correlation. Compared to the forward flow volume indices, the retrograde flow volume index had a lower correlation with the estimated aortic regurgitation volume indices and had widely dispersed data with larger prediction intervals.

CONCLUSION

Large variations in systolic forward, diastolic retrograde and net forward flow volumes were observed at different levels of the aortic valve and ascending aorta. Direct measurement of aortic regurgitation volume and fraction is inaccurate and should be abandoned. Instead, calculation of the aortic regurgitation volume from more reliable data is advised. We recommend subtracting pulmonary blood flow from systolic forward flow measured at the aortic valve hinge points at end-diastole as a more accurate and consistent method for calculating the volume of aortic regurgitation.

Left ventricular sphericity index predicts systolic dysfunction in rats with experimental aortic regurgitation

Although an increased left ventricular (LV) diastolic diameter (DD) and a decreased ejection fraction have been used as markers for the surgical replacement of an insufficient aortic valve, these signals may be observed when irreversible myocardium damage has already occurred. The aim of this study was to determine whether change in LV geometry predicts systolic dysfunction in experimental aortic regurgitation. Male Wistar rats underwent surgical acute aorta regurgitation (aorta regurgitation group; n = 23) or a sham operation (sham group; n = 12). After the procedure, serial transthoracic echocardiograms were performed at 1, 4, 8, and 16 wk. At the end of protocol, the LV, lungs, and liver were dissected and weighed. During the follow-up, no animal developed overt heart failure. There was a correlation between the LV sphericity index and reduced fractional shortening ( P < 0.001) over time. A multiple regression model showed that the LVDD-sphericity index association at 8 wk was a better predictor of decreased fractional shortening at week 16 ( R2 = 0.50; P < 0.001) than was the LVDD alone ( R2 = 0.39; P = 0.001). LV geometry associated with increased LVDD improved the prediction of systolic dysfunction in experimental aortic regurgitation.