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

Manisha Sahota1, Sepas Ryan Saraskani1, Hao Xu1

  • 1Department of Biomedical Engineering, King's College London, 1 Lambeth Palace Rd, London, SE1 7EU, UK.

Insights

Machine learning models can predict left ventricular outflow tract obstruction (LVOTO) in hypertrophic cardiomyopathy (HCM) using cardiac MRI (CMR) anatomical metrics. The distance from the mitral valve to the septum best predicts obstruction, with combined metrics offering superior risk assessment.

Area of Science:

  • Cardiology
  • Medical Imaging
  • Machine Learning

Background:

  • Left ventricular outflow tract obstruction (LVOTO) is a frequent complication of hypertrophic cardiomyopathy (HCM).
  • The precise relationship between anatomical characteristics and LVOTO severity in HCM remains incompletely understood.
  • Accurate assessment of LVOTO is crucial for patient management and risk stratification.

Purpose of the Study:

  • To develop and validate machine learning (ML) methods for evaluating LVOTO in HCM patients.
  • To quantify the associations between specific anatomical metrics derived from cardiac magnetic resonance (CMR) imaging and the degree of LVOTO.
  • To identify key anatomical predictors of LVOTO in HCM.

Main Methods:

  • Retrospective analysis of 1905 HCM Registry participants.
  • Automatic detection of 14 landmarks on three-chamber cine CMR images to derive 11 anatomical metrics.
  • Linear and logistic regression models to assess relationships with LVOTO (defined by Doppler pressure drop > 30 mmHg).
  • Evaluation of ML model performance using the area under the receiver operating characteristic curve (AUC).

Main Results:

  • The distance from the anterior mitral valve leaflet tip to the basal septum (AML-BS) showed the strongest correlation with Doppler pressure drop (R² = 0.19).
  • A multivariate stepwise regression model incorporating AML-BS, AML length to aortic valve diameter ratio, AML length to LV width ratio, and midventricular septal thickness achieved an AUC of 0.84.
  • Combinations of anatomical metrics, particularly those related to septal hypertrophy, LV geometry, and AML anatomy, significantly improved LVOTO prediction compared to individual groups.

Conclusions:

  • Standard three-chamber CMR cine acquisitions provide valuable anatomical metrics for assessing LVOTO risk in HCM.
  • A combination of geometric factors, including AML-BS, offers the best predictive capability for LVOTO.
  • These findings support the use of CMR-derived anatomical data to identify HCM patients who may require further investigation for LVOTO.