Dilated-Hypokinetic Evolution of Hypertrophic Cardiomyopathy
Key result
Dilated-hypokinetic evolution linked to significantly lower cardiovascular death-free survival vs classic HCM.
- P<0.04
- n=222
Why the study?
The incidence, risk factors, and prognosis of dilated-hypokinetic evolution in hypertrophic cardiomyopathy, especially in pediatric patients, were not well characterized.
Key Points
- To determine the incidence, baseline clinical risk factors, and long-term prognosis of dilated-hypokinetic evolution in pediatric and adult patients with hypertrophic cardiomyopathy.
- Prospectively evaluated N=222 consecutive patients with hypertrophic cardiomyopathy (65% male, 19% aged ≤18 years) for a mean follow-up of 11 ± 9 years.
- Measured baseline prevalence and longitudinal incidence of dilated-hypokinetic transition in patients presenting with classic hypertrophic cardiomyopathy.
- Identified multivariable risk factors for cardiovascular mortality using Cox proportional hazards regression analysis.
- Dilated-hypokinetic hypertrophic cardiomyopathy was diagnosed in 12 patients at baseline (prevalence 4.9%) and developed longitudinally in 12 of 210 classic patients (incidence 5.3 per 1,000 patient-years).
- Patients with dilated-hypokinetic evolution were younger at diagnosis (32 ± 14 vs. 41 ± 21 years, P=0.04), more often had a family history of cardiomyopathy (61% vs. 26%, P=0.002) or sudden death (43% vs. 19%, P=0.01), and had greater interventricular septal thickness (23 ± 3 vs. 19 ± 6 mm, P=0.004) and posterior wall thickness (15 ± 3 vs. 13 ± 4 mm, P=0.006).
- Cardiovascular death-free survival was significantly lower in patients with dilated-hypokinetic disease (P<0.04), with left ventricular wall thickness (HR 1.07, 95% CI 1.01–1.14, P=0.03) and end-diastolic diameter (HR 1.08, 95% CI 1.04–1.11, P=0.0001) acting as independent mortality predictors.
Study Design
Type
Cohort (n=222)
Multicenter
No
Structured PICO
P
Population
222 consecutive patients with hypertrophic cardiomyopathy, including adult and pediatric populations, prospectively followed for a mean of 11 years.
C
Comparator
Patients who maintained classic HCM
O
Outcome
Cardiovascular death-free survivalhard clinical
Main Result
p-value: p=<0.04
Dilated-hypokinetic evolution of hypertrophic cardiomyopathy is a rare but high-risk phenotype associated with younger age at diagnosis, positive family history, greater initial wall thickness, and an increased risk of cardiovascular death.
Key expert perspectives
Captured external expert commentary on this paper, strongest first. Original sources are linked where available.
“Although the number of patients in this study is small (reflecting the rarity of dilated-phase HCM) and does not allow clear prospective identification of those at increased risk for dilation, these findings need to be considered in the context of the genetic and metabolic recipe of HCM.”
Implication
Dilated-hypokinetic HCM evolution signals higher cardiovascular mortality; this Level 3 cohort finding leaves open whether targeted surveillance improves outcomes.
Abstract
OBJECTIVES: This study sought to investigate the incidence, risk factors, and prognosis of dilated-hypokinetic evolution in a large cohort of patients with hypertrophic cardiomyopathy (HCM) followed up at a cardiology center serving both the pediatric and the adult population. BACKGROUND: The available data on this evolution of HCM mainly regards prevalence (rather than incidence) in adults, with very little being known about the pediatric population. METHODS: A total of 222 consecutive HCM patients (65% men, 19% < or =18 years old) were prospectively evaluated for a mean follow-up of 11 +/- 9 years. RESULTS: A diagnosis of dilated-hypokinetic HCM was made in 12 patients at first evaluation (11 without previous septal myectomy surgery; prevalence, 4.9%). Twelve of the 210 patients with classic HCM at first evaluation underwent dilated-hypokinetic evolution (incidence, 5.3/1,000 patient-years). Patients with prevalent/incident dilated-hypokinetic evolution were younger at first evaluation (32 +/- 14 years vs. 41 +/- 21 years, p = 0.04) and more often had a family history of HCM (61% vs. 26%, p = 0.002) or sudden death (43% vs. 19%, p = 0.01) with respect to patients who maintained classic HCM. Moreover, they showed greater interventricular septum (23 +/- 3 mm vs. 19 +/- 6 mm, p = 0.004) and posterior wall (15 +/- 3 mm vs. 13 +/- 4 mm, p = 0.006) thickness. Cardiovascular death-free survival was lower among patients with dilated-hypokinetic HCM (p < 0.04). Cox proportional hazards regression analysis identified left ventricular wall thickness (hazard ratio [HR] = 1.07; 95% confidence interval [CI], 1.01 to 1.14; p = 0.03) and end-diastolic diameter (HR = 1.08; 95% CI 1.04 to 1.11; p = 0.0001) as independent predictors of cardiovascular death. CONCLUSIONS: Dilated-hypokinetic evolution is rare but not exceptional in HCM. Young age at diagnosis, family history of HCM, and greater wall thickness are incremental risk factors for dilated-hypokinetic HCM, which carries an ominous prognosis.
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Cite This Study
Biagini et al. (2005) conducted a cohort in Hypertrophic cardiomyopathy (n=222). Dilated-hypokinetic evolution vs. Classic hypertrophic cardiomyopathy was evaluated on Cardiovascular death-free survival (p=<0.04). Dilated-hypokinetic evolution occurred at an incidence of 5.3 per 1,000 patient-years and was associated with significantly lower cardiovascular death-free survival (p<0.04) compared to classic HCM.