Explainable machine learning for estimation of elevated left ventricular filling pressure: a multicenter validation
摘要
Guideline-recommended algorithms (GL-algorithm) often results in indeterminate left ventricular filling pressure (LVFP). Despite high accuracy, machine learning (ML) methods lack interpretability, which necessitates the development of explainable ML models for clinical use.
ObjectiveTo develop an explainable ML model for estimating LVFP, providing patient-level interpretation using gold-standard right heart catheterization (RHC) data.
MethodsWe retrospectively enrolled 956 patients who underwent echocardiography and RHC at three hospitals within a median of 3 days. Two extreme gradient boosting models were trained using data from two hospitals (n = 621) to estimate elevated pulmonary artery wedge pressure (PAWP ≥ 18 mmHg) as a surrogate for elevated LVFP. Model 1 used variables from GL-algorithm, while Model 2 used variables selected based on Shapley additive explanations (SHAP) values. Models’ area under the receiver-operating characteristic curve (AUROC) for elevated LVFP were compared using external test data from the other hospital (n = 335).
ResultsOverall, 31.0% had elevated PAWP, and 42.7% were classified as indeterminate LVFP by GL-algorithm, whereas the ML models classified all patients. AUROCs of Model 1 (0.82, 95% CI 0.73–0.92) and Model 2 (0.83, 95% CI 0.75–0.91) in classifiable cases by GL-algorithm significantly outperformed that of GL-algorithm (0.72, 95% CI 0.60–0.83, p = 0.020 and 0.016, respectively), Model 2 performed equally well for indeterminate cases. SHAP force plots visualized each variable’s contribution to the ML model’s decision for each patient.
ConclusionsExplainable ML outperformed GL-algorithm in estimating LVFP, providing a user-friendly tool for clinicians with patient-level interpretability.
Graphical abstractMachine learning models improve estimation of elevated PAWP: Using XGBoost, ML models to estimate PAWP elevation from the echocardiographic parameters were developed. Compared with conventional algorithm, the ML models predicted PAWP elevation more accurately. By interpreting the impact of each parameter on the prediction using SHAP, the importance of each parameter for prediction could be understood for each patient and for the entire population. AUROC area under the receiver-operating characteristic curve, CI confidence interval, LAVI left atrial volume index, ML machine learning, PAWP pulmonary artery wedge pressure, RHC right heart catheterization, SHAP shapley additive explanations, TRV tricuspid regurgitation pressure gradient, TTE transthoracic echocardiography, XGBoost extreme gradient boosting