Ji-won Hwang, Sang-Chol Lee , Darae Kim, Jihoon Kim, Eun Kyoung Kim, Sung-A. Chang, Sung-Ji Park, Sung Mok Kim, Yeon Hyeon Choe, Seung Woo Park
Abstract
We aimed to evaluate the additive value of cardiovascular magnetic resonance imaging (CMR) and cardiopulmonary exercise test (CPET) to predict clinical outcomes in patients with HCM. We enrolled 373 patients with HCM and normal left ventricular systolic function who underwent CPET and CMR. The primary outcome was a clinical composite of all-cause death, cardiac transplantation, stroke, heart failure requiring hospitalization and defibrillator implantation. During a follow-up of 70.70 ± 30.74 months, there were 84 composite clinical events. Peak oxygen consumption during CPET was significantly lower (18.51±13.25 vs. 24.59±13.28 mL/kg/min, p < 0.001) and abnormal hemodynamic response to exercise was more frequently detected (41.7 vs. 20.8%, p<0.001) in the group with composite clinical events.
Introduction
Hypertrophic cardiomyopathy (HCM) is a cardiac disease characterized by inappropriate myocardial hypertrophy and a non-dilated left ventricle with frequent myocardial fibrosis. It is associated with variable clinical expressions and outcomes [1, 2].
Reduced exercise capacity is common in patients with HCM, affecting these patients over a broad spectrum of clinical severity [3]. Exercise stress testing has been shown to be useful for the assessment of functional capacity and risk stratification, evaluation of symptoms, and monitoring the response to therapy in patients with HCM [4]. Peak oxygen consumption (peak VO2) during cardiopulmonary exercise testing (CPET) is known to be a useful marker for the functional capacity of patients with HCM [5, 6].
Materials and Methods
Study population and clinical characteristics
The study was performed using data obtained from the prospective observational HCM registry of the Samsung Heart Vascular Stroke Institute, Seoul, Korea. A total of 591 prospectively enrolled patients, who were diagnosed with HCM and underwent CMR between 2008 and 2015, were included. The echocardiographic criteria for inclusion in the HCM registry included the following definition of guidelines: HCM is defined by the presence of increased left ventricular (LV) wall thickness that is not solely explained by abnormal loading conditions [18, 19]. Patients with uncontrolled hypertension, uncontrolled ventricular arrhythmias, severe valvular diseases, other concomitant systemic diseases–including malignancy–and poor echocardiographic windows for analysis were excluded [3, 20–22].
Results
The incremental prognostic value of non-sustained VT on Holter, echocardiographic parameters, CMT parameters, and CPET parameters over conventional clinical variables ranged from 0.700 to 0.790 on the basis of the value of the AUC obtained by the ROC curve analysis (Table 4 and Fig 1). All models showed statistical significance for the prediction of composite clinical outcomes as the NRI value (all p-values < 0.05) (Table 4) by risk reclassification analysis. Particularly, in Model 4, where CPET variables were added to clinical, echocardiographic, and CMR parameters, definite incremental values for composite outcome prediction were significantly identified (p-values < 0.005 on NRI and IDI values).
Discussion
Our findings confirmed that the presence and amount of myocardial fibrosis could be a determinant of composite clinical outcomes in patients with HCM, and could also add value to conventional factors. The uniqueness of our study was that we demonstrated that CPET may also be an important tool for risk stratification in HCM on top of CMR findings. Moreover, we showed that functional capacity demonstrated by peak VO2 was an independent predictor of outcomes in patients with HCM, with incremental value as a risk factor when added to the alleged parameters.
Conclusion
This study demonstrated that CPET-derived peak oxygen consumption level, especially when combined with LGE on CMR, added value to conventional clinical risk factors as prognostic factors in patients with HCM, especially in terms of heart failure-related admissions. Dynamic objective assessment of patients with CPET may aid in elucidating various symptoms, improving treatment planning, and assessing risk stratification in patients with HCM.
Citation: Hwang J-w, Lee S-C, Kim D, Kim J, Kim EK, Chang S-A, et al. (2023) Role of cardiovascular magnetic resonance imaging and cardiopulmonary exercise test in predicting composite clinical outcomes in patients with hypertrophic cardiomyopathy. PLoS ONE 18(5): e0285887. https://doi.org/10.1371/journal.pone.0285887
Editor: Tomohiko Ai, Ohio State University, UNITED STATES
Received: March 23, 2022; Accepted: May 4, 2023; Published: May 16, 2023
Copyright: © 2023 Hwang et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Data Availability: Our data contain sensitive privacy information. Data are available from the Samsung Medical Center Institutional Review Board (contact via email: [email protected]; or telephone: 02-3410-1847) for researchers who meet the criteria for access to confidential data.
Funding: The authors received no specific funding for this work.
Competing interests: The authors have declared that no competing interests exist.
https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0285887#sec008
