Circumferential deformation in diagnosis and risk assessment of patients with left ventricular non-compaction

Introduction

Echocardiography-based deformation analysis is used for studying left ventricular (LV) mechanics and have an emerging role in the diagnosis of cardiomyopathies. Left ventricular non-compaction (LVNC) is a rare cardiomyopathy characterised by a two-layered LV myocardium with prominent trabeculae separated by deep recesses perfused from the LV cavity. Left ventricular hypertrabeculation (LVHT) may be difficult to differentiate from LVNC. In this study, we aim to develop a diagnostic algorithm based on the circumferential deformation (CD) of LVNC, LVHT and controls; and find their associations with LVNC outcomes.

Methods

We compared 45 LVNC patients, 45 LVHT individuals, and 45 matched healthy controls. LVNC was diagnosed according to current echocardiographic criteria. LVHT was defined as presence of three or more trabeculae in the LV apex visualised in both parasternal short axis and apical views. Controls had a normal echocardiographic examination and no evidence of cardiovascular disease. Strain analysis was performed using TomTec Image-Arena (version 4.6).

Results

Receiver observer characteristics curve (ROC) analyses revealed that GCS <22.3% differentiated LVNC from control or LVHT. In individuals with global circumferential strain (GCS) below 22.3%, an apical peak circumferential strain (PCS) cut-off value of 18.4% differentiated LVNC [<18.4%] and LVHT [≥18.4%] (fig. 1). An independent echocardiographer (Table 1) performed blind validation of diagnosis on 32 subjects from each group.

Combined endpoint of cardiovascular events in LVNC (CVE) is described in figure 2. Multi-variate regression analyses have shown that GCS was associated with 11-fold increased risk of CVE independent of LVEF and NC:C ratio, while global longitudinal strain (GLS) displayed only 2-fold increased risk. Regional basal and apical peak circumferential or longitudinal strain, left ventricular twist, basal-apical rotation ratio have shown significant associations (Fig. 3).

Conclusions

A diagnostic algorithm with GCS and aPCS (threshold value 18.4%) differentiates LVNC from LVHT and control with very high sensitivity and specificity independent of additional echocardiographic or clinical information. Circumferential strain derived parameters exhibit a very strong association with outcomes independent of LVEF and NC:C ratio. Absence of CVE in LVHT provides further evidence on the distinct nature of LVNC and LVHT.

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): 2018 research grant from the Swiss Heart Foundation

P1842Impact of left ventricular outflow tract sphericity on transcatheter heart valve hemodynamics and outcome after transcatheter aortic valve implantation

Background

Accurate assessment of aortic annulus and left ventricular outflow tract (LVOT) anatomy is mandatory for appropriate device selection in order to achieve optimal deployment of transcatheter heart valves (THV).

Aim

To evaluate the impact of LVOT shape as determined by the sphericity index (ratio of long and short LVOT diameter) on THV hemodynamics.

Methods

1000 consecutive patients diagnosed with severe symptomatic aortic stenosis and undergoing TAVI between May 2008 and July2017 were analyzed. Assessment of aortic root dimensions including the LVOT was performed by contrast-enhanced multidetector computed tomography (MDCT) in all patients. The primary endpoint was 30-day device success as defined by the VARC-2 criteria. Secondary endpoints included all-cause mortality, cardiovascular mortality, permanent pacemaker implantation (PPI), and a 30-day combined early safety endpoint (all-cause mortality, all strokes, life threatening bleeding, acute kidney injury stage 2 or 3, CAD obstruction requiring intervention, major vascular complication, valve related dysfunction requiring repeat intervention).

Results

Patients were divided into 3 groups according to LVOT sphericity index (SI) quartiles. The three groups (low-SI: 0.4–0.63, n=250; mid-SI: 0.64–0.75, n=500; high-SI: 0.76–1.0, n=250) were well balanced in terms of baseline characteristics, except for gender distribution with more female patients in the low-SI group (36.8% vs. 49.0% vs. 60.0%; p=0.ehz748.05941). Assessment of calcification volume and Agatston score demonstrated significantly higher aortic valve and LVOT calcification in the high-SI group. The primary endpoint of device success after 30-days did not differ between the 3 groups (92.4% vs 91.9% vs. 87.9%; p=NS). However, moderate or severe paravalvular regurgitation (PAR) occurred significantly more often in the high-SI as compared to the other groups (4.1% vs. 5.2% vs. 10.6%; p=0.004 for low-SI vs. high-SI). In contrast, PPI rates, the early safety endpoint at 30 days, and all-cause mortality at 1 year did not differ between the groups. In the high-SI group implantation of a BE valve was associated with a significantly higher rate of device success as compared to SE valves (93.8% vs. 82.2%, p=0.007). This difference was driven by a higher rate of moderate or severe PAR (6.9% vs. 15.3%, p=0.007) in patients treated with SE valves. Moreover, patients in the high-SI group receiving a SE valve required more often a PPI than those treated with a BE valve (26.2% vs 13.3%, p=0.012). There was no difference between the THV types in the other SI groups in terms of primary and secondary endpoints.

Conclusion

A more circular LVOT is associated with higher aortic valve and LVOT calcification. Implantation of a SE THV results in higher rates of moderate or severe PAR and persistent conduction disorder requiring PPI in such patients.

P2270Clinical characteristics and outcomes after TAVI in patients reclassified to moderate aortic stenosis by integration of multimodality imaging and pressure recovery

Background

Accurate assessment of aortic stenosis (AS) severity is critical for the correct management of patients. This has become particularly important because the introduction of transcatheter aortic valve implantation (TAVI) has markedly increased the number of patients eligible for aortic valve replacement

Aims

To assess whether reclassification of aortic stenosis (AS) grading by integration of fusion imaging using data from transthoracic echocardiography (TTE) and multidetector computed tomography (MDCT) under consideration of the energy loss index (ELI) predicts outcome in patients undergoing transcatheter aortic valve implantation (TAVI).

Methods

197 consecutive patients with symptomatic severe AS undergoing TAVI at our University Heart Center were included in this study. AS severity was determined according to current guidelines.

Results

Left ventricular outflow tract (LVOT) area derived from TTE was smaller than the planimetric area in MDCT due the ovoid shape of the LVOT (3.4±0.12 cm2 vs. 4.5±0.23 cm2; p<0.01). The sinotubular junction (ST-junction) diameter measured in TTE was similar to maximal, minimal, and mean diameters determined by MDCT. The sphericity index confirmed an almost circular anatomy of ST-junction, and its area derived from TTE was similar to the planimetric area in MDCT. Fusion aortic valve area index (fusion AVAi) assessed by inserting MDCT derived planimetric LVOT area in the continuity equation was significantly higher in all patients compared to conventional AVAi. 62 patients were reclassified from severe to moderate AS because fusion AVAi was >0.6 cm2/m2. ELI was calculated for conventional AVAi and fusion AVAi each with ST-junction area determined by both TTE and MDCT. Calculating ELI with fusion AVAi resulted in significantly larger effective orifice area, with values >0.6 cm2/m2 in 83 patients (ST-junction area from echo) and 85 patients (ST-junction area from MDCT). Similarly, calculating ELI with conventional AVAi resulted in significantly larger effective orifice area as compared to AVAi alone. Reclassified patients had lower mean transvalvular pressure gradients, lower myocardial mass, less symptoms according to NYHA classification, and lower proBNP levels at baseline. While both groups exhibited improvement of functional status at 1 year of follow-up, the survival rate at 3 years after TAVI was higher in patients reclassified to moderate AS (81% versus 66%; p=0.02).

Conclusion

Integration of TTE and MDCT derived values for calculation of ELI reclassifies the severity of AS in 43% of patients initially diagnosed with severe AS.Although reclassified patients display less advanced valve disease at baseline, TAVI results in functional improvement in all patients. Furthermore, patients reclassified to moderate AS exhibit higher survival rates at 3 years after aortic valve replacement.