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The Clinical Trajectory of NYHA Functional Class I Patients With Obstructive Hypertrophic Cardiomyopathy
Monica Ahluwalia1, Jiankang Liu2, Iacopo Olivotto3
1Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA; Boston Medical Center Boston University Chobanian and Avedisian School of Medicine, Boston, Massachusetts, USA.
Insights
Patients with obstructive hypertrophic cardiomyopathy (oHCM) in NYHA functional class I experienced fewer adverse events than class II patients over 5 years. However, older age, female sex, and larger left atrial diameter increased risks in class I oHCM patients.
Area of Science:
- Cardiology
- Internal Medicine
- Genetics
Background:
- Understanding the natural history of obstructive hypertrophic cardiomyopathy (oHCM) in patients with New York Heart Association (NYHA) functional class I is crucial.
- The Sarcomeric Human Cardiomyopathy Registry (SHaRe) provides valuable data for such investigations.
Purpose of the Study:
- To describe the natural history of oHCM in NYHA functional class I patients.
- To compare outcomes between NYHA class I and class II oHCM patients.
- To identify baseline characteristics associated with clinical events in NYHA class I oHCM patients.
Main Methods:
- A multicenter registry (SHaRe) was utilized.
- Patients with oHCM in NYHA functional class I were compared to those in NYHA functional class II.
- Incident clinical events included worsening symptoms, reduced ejection fraction, arrhythmias, stroke, interventions, or death.
- Statistical models included Kaplan-Meier, Cox proportional hazards, and restricted cubic spline analyses.
Main Results:
- Among 1,239 oHCM patients, 598 were NYHA class I and 641 were NYHA class II.
- The 5-year composite event rate was 28% for NYHA class I versus 44% for NYHA class II (P < 0.001).
- In NYHA class I patients, increased risk of adverse events was associated with larger left atrial diameter (≥45 mm), female sex, and older age.
Conclusions:
- NYHA functional class I patients with oHCM demonstrate a better prognosis than NYHA class II patients.
- A significant proportion (over 25%) of NYHA class I oHCM patients experienced adverse events within 5 years.
- Targeted strategies are needed to mitigate clinical outcomes in NYHA class I oHCM patients, particularly those with specific risk factors.
Background:
An improved understanding of the natural history in NYHA functional class I patients with obstructive hypertrophic cardiomyopathy (oHCM) is needed.
Objectives:
Using a multicenter registry (SHaRe [Sarcomeric Human Cardiomyopathy Registry]), this study described the natural history in patients with oHCM who were classified as NYHA functional class I at the initial visit compared with patients classified as NYHA functional class II and reported baseline characteristics associated with incident clinical events.
Methods:
Incident events assessed included a composite of NYHA functional class III to IV symptoms, left ventricular ejection fraction <50%, atrial fibrillation, stroke, ventricular arrhythmias, septal reduction therapy, ventricular assist device or transplantation, or death. Factors associated with incident events were determined using Kaplan-Meier, Cox proportional hazards, and restricted cubic spline models.
Results:
Of 7,964 patients with HCM in SHaRe, 1,239 patients with oHCM met inclusion criteria; 598 were in NYHA functional class I at the initial visit (age 48 ± 17 years; 31.1% female; peak gradient, 75 ± 40 mm Hg). At 5-year follow-up, the composite event rate of NYHA functional class I patients was 28% compared with 44% (P < 0.001) in 641 NYHA functional class II patients with oHCM (age 54 ± 16 years; 46.5% female; peak gradient, 83 ± 39 mm Hg). Left atrial (LA) diameter ≥45 mm (HR: 1.56 [95% CI: 1.14-2.12]; P = 0.005), female sex (HR: 1.61 [95% CI: 1.16-2.24]; P = 0.003), and older age (HR: 1.21 per 10 years [95% CI: 1.09-1.34]; P < 0.001), but not the magnitude of left ventricular outflow tract obstruction, were associated with a higher risk of the composite outcome in NYHA functional class I patients.
Conclusions:
Although NYHA functional class I patients with oHCM fared better than NYHA functional class II patients, more than one-fourth experienced adverse events over 5-year follow-up, especially if they were older, female, and/or had LA enlargement. Strategies to reduce the rate of clinical outcomes in NYHA functional class I patients warrant further study.
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