Risk Of Left Ventricular Outflow Tract Obstruction Research Articles

New echocardiographic screening tool for left ventricular tract obstruction risk assessment in TMVR

BackgroundTranscatheter mitral valve replacement (TMVR) is an alternative to conventional surgery to treat severe mitral disease but its use is limited by the risk of left ventricular outflow tract obstruction (LVOTO). Screening depends on ECG-gated computed tomography (CT) that is not widely available and requires contrast. We developed and validated a transthoracic echocardiographic (TTE) method to assess the risk of LVOTO after TMVR with the Tendyne System. MethodsWe measured the LVOT longitudinal area on preoperative TTE dataset of patients screened for TMVR. The LVOT was measured as the box-area included by the aortic valve annulus, the anterior mitral leaflet (AML), the c-septum distance line, and the respective length of the AML on the interventricular septum. We analyzed the correlation between the TTE LVOT-box and the CT-measured neoLVOT area. Prediction performance for eligible patients was tested with ROC curves. ResultsThirty-nine patients were screened, out of 14 patients (36%) not eligible for TMVR, 8 had risk of LVOTO. We found a linear correlation between the TTE LVOT-box and the CT-measured Neo-LVOT (r = 0.6, p = 0.002). ROC curve showed that the method is specific and sensitive and the cut-off value of the measure LVOT-box is 350 mm2. ConclusionsThe proposed method is reliable to evaluate the risk of LVOTO after TMR with the Tendyne System. It is quick and easy and can be used as a first-line assessment in the outpatient clinic. Patients with LVOT-box <350 mm2 should not be further screened with ECG-gated cardiac CT.

Peri-procedural management of transcatheter mitral valve replacement in patients with heart failure.

Over the past decade, transcatheter mitral valve replacement (TMVR) technologies have evolved with the objective of improving outcomes for patients with severe mitral regurgitation (MR) deemed unsuitable for conventional mitral valve surgery. Although the safety and efficacy of transcatheter edge-to-edge mitral valve repair (TEER) is well-established, there is a sense amongst innovators that a major advantage of TMVR may be to offer a more complete solution for the correction of MR in patients whose complex anatomy means that the likelihood of achieving grade 0 or 1 MR with TEER is low. However, abrupt correction of MR in a poorly prepared left ventricle poses a number of unique haemodynamic challenges, particularly when sudden elimination of regurgitant flow causes a relative increase in left ventricular (LV) afterload. Rapid reduction in LV cavity size following MR elimination may itself result in relative LV outflow tract obstruction (LVOTO), irrespective of the intrinsic risk of LVOTO associated with TMVR. Nevertheless, TMVR on a beating heart affords the opportunity to study real-time invasive cardiac indices in high-risk patients with acute reversal of severe MR.

Machine learning evaluation of LV outflow obstruction in hypertrophic cardiomyopathy using three-chamber cardiovascular magnetic resonance

Left ventricular outflow tract obstruction (LVOTO) is common in hypertrophic cardiomyopathy (HCM), but relationships between anatomical metrics and obstruction are poorly understood. We aimed to develop machine learning methods to evaluate LVOTO in HCM patients and quantify relationships between anatomical metrics and obstruction. This retrospective analysis of 1905 participants of the HCM Registry quantified 11 anatomical metrics derived from 14 landmarks automatically detected on the three-chamber long axis cine CMR images. Linear and logistic regression was used to quantify strengths of relationships with the presence of LVOTO (defined by resting Doppler pressure drop of > 30 mmHg), using the area under the receiver operating characteristic (AUC). Intraclass correlation coefficients between the network predictions and three independent observers showed similar agreement to that between observers. The distance from anterior mitral valve leaflet tip to basal septum (AML-BS) was most highly correlated with Doppler pressure drop (R2 = 0.19, p < 10–5). Multivariate stepwise regression found the best predictive model included AML-BS, AML length to aortic valve diameter ratio, AML length to LV width ratio, and midventricular septal thickness metrics (AUC 0.84). Excluding AML-BS, metrics grouped according to septal hypertrophy, LV geometry, and AML anatomy each had similar associations with LVOTO (AUC 0.71, 0.71, 0.68 respectively, p = ns), significantly less than their combination (AUC 0.77, p < 0.05 for each). Anatomical metrics derived from a standard three-chamber CMR cine acquisition can be used to highlight risk of LVOTO, and suggest further investigation if necessary. A combination of geometric factors is required to provide the best risk prediction.

Novel Multiphase Assessment for Predicting Left Ventricular Outflow Tract Obstruction Before Transcatheter Mitral Valve Replacement

ObjectivesThis study proposes a physiologic assessment of left ventricular outflow tract obstruction (LVOTO) that accommodates changes in systolic flow and accounts for the dynamic neo–left ventricular outflow tract (LVOT). BackgroundPatients considered for transcatheter mitral valve replacement trials often screen-fail because of the perceived risk of LVOTO. In the Intrepid Global Pilot Study, assumed risk of LVOTO was based on computed tomography estimates of the neo-LVOT area computed at end-systole. However, this may overestimate actual risk. MethodsRetrospective analyses were performed for screen-failed patients for potential LVOTO (n = 33) and treated patients (n = 29) with available dynamic computed tomography. A multiphase assessment of the neo-LVOT area was performed and represented as: 1) multiphase average; and 2) early systolic value. Prospective evaluation was performed in 9 patients approved for enrollment with multiphase and early systole methods that would have previously screen-failed with the end-systolic approach. ResultsOf 166 patients screened for possible inclusion; 32 were screen-failed for nonanatomical reasons. Screen failure for assumed LVOTO risk occurred in 37 of 134 (27.6%) patients. Retrospective analysis indicated a potential enrollment increase of 11 of 33 (33.3%) and 18 of 33 (54.5%) patients using multiphase and early systolic assessment methods. In the prospective cohort, there were no clinical observations of LVOTO 30 days post-procedure, despite assumed risk based on end-systolic estimates. ConclusionsMultiphase, and specifically early systolic, assessment of the neo-LVOT may better determine risk of LVOTO with transcatheter mitral valve replacement compared with end-systolic estimates. This novel approach has the potential to significantly increase patient eligibility, with over one-half of patients previously screen-failed now eligible for treatment.

Transcatheter Mitral Valve Planning and the Neo-LVOT: Utilization of Virtual Simulation Models and 3D Printing.

Transcatheter mitral valve replacement (TMVR) is an emerging alternative for patients with severe mitral valve regurgitation who are considered at high risk for conventional surgical options. The early clinical experience with TMVR has shown that pre-procedural planning with computed tomography (CT) is needed to mitigate the risk of potentially lethal procedural complications such as left ventricular outflow tract (LVOT) obstruction. The goal of this review is to provide an overview of key concepts relating to TMVR pre-procedural planning, with particular emphasis on imaging-based methods for predicting TMVR-related LVOT obstruction. Risk of LVOT obstruction can be assessed with CT-based pre-procedural planning by using virtual device simulations to estimate the residual 'neo-LVOT' cross-sectional area which remains after device implantation. A neo-LVOT area of less than 2cm2 is currently thought to increase the risk of obstruction; however, additional studies are needed to further validate this cutoff value. Three-dimensional printing and personalized computational simulations are also emerging as valuable tools which may offer insights not readily confered by conventional two-dimensional image analysis. The simulated neo-LVOT should be routinely assessed on pre-procedural CT when evaluating anatomical suitability for TMVR.

Echocardiographic Predictors of Left Ventricular Outflow Tract Obstruction following Repair of Atrioventricular Septal Defect.

Left ventricular outflow tract obstruction (LVOTO) is a common complication following surgical repair of atrioventricular septal defect (AVSD). We sought to determine predictors of LVOTO based on echocardiograms performed prior to initial repair of AVSD. Of the 415 children that had repair of AVSD from 2003 to 2012, 17 children were identified with LVOTO that required surgical intervention. Thirty-four patients with repaired AVSD and no LVOTO served as controls. Patient demographics, cardiac surgery type, and echocardiogram results at last follow-up were collected. Off-line analysis of the echocardiogram prior to AVSD repair was done to obtain: left ventricular outflow tract (LVOT) and interventricular septal diameter, chordae across LVOT, aortoseptal angle, left ventricular (LV) inflow/outflow length ratio, inferior displacement of the atrioventricular (AV) valve, atrioventricular valve index (AVVI) and presence of coarctation of the aorta. The LVOTO group had significantly smaller indexed LVOT diameters (P < .001), increased likelihood of chordae crossing the LVOT (P = .010), decreased LV inflow/outflow length ratio (P < .001), decreased AVVI (P = .014) and increased presence of coarctation of the aorta (P = .003) compared to control patients. A multiple logistic regression model including presence of chordae in the LVOT [OR 5.32, 95% CI: (1.24-22.78, P = .024] and an indexed LVOT diameter ≤2.5 cm/m2 [OR 5.41, 95% CI: (1.15-25.39) P = .032] demonstrated each to be independently associated with the development of LVOT obstruction (area under the receiving operating curve = 0.77). Chordae across the LVOT and an indexed LVOT diameter of ≤2.5 cm/m2 are associated with a higher risk of development of LVOTO following repair of AVSD. Identification of these risk factors on echocardiogram prior to initial AVSD repair can be useful in evaluating for future risk of LVOTO and the need for closer clinical follow-up.

Late Cardiovascular Complications After Surgical or Balloon Angioplasty of Coarctation of Aorta in an Asian Cohort

Late cardiovascular complications after intervention for coarctation of the aorta (CoA) might be common. Such data, especially in Asian populations, are still limited. A total of 169 patients with CoA who survived balloon (n = 41) or surgical (n = 128) intervention from 1986 to 2004 were enrolled. The total follow-up was 1,776 patient-years, and the patient age at last follow-up was 14.7 +/- 8.5 years. Reintervention for recoarctation, systemic hypertension, and left ventricular outflow tract obstruction (LVOTO) was subsequently noted in 57 (34%), 36 (21.3%), and 24 (14.2%) patients, respectively, without significant differences between the balloon and surgical groups. The 20-year freedom from reintervention, systemic hypertension, and LVOTO rate was 52%, 78.6%, and 80.8% in the balloon group and 59%, 51%, and 81.9% in the surgical group, respectively. The age at CoA intervention and the aortic geometry after CoA intervention of gothic type were common risk factors for reintervention for recoarctation and late systemic hypertension. In contrast, the presence of bicuspid aortic valves and gothic arch geometry after CoA intervention increased the risk of LVOTO. Plasma renin/aldosterone activities were not elevated in those with or without systemic hypertension. In conclusion, the profile of reintervention for recoarctation and late systemic hypertension after CoA interventions in our Asian cohort with CoA was similar to that observed in white patients. Asian patients might have a lower risk of LVOTO.