Evaluation of pathological criteria for diagnosis of hypertrophic cardiomyopathy
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Current pathological criteria for diagnosing hypertrophic cardiomyopathy (HCM) are imperfect. The histologic HOCM index (HHI) was most common in HCM patients, and higher in those with sudden death.
Area of Science:
- Cardiovascular Pathology
- Histopathology
- Cardiac Diseases
Background:
- Hypertrophic cardiomyopathy (HCM) diagnosis relies on pathological criteria.
- Myofibre disarray is a key feature, but its diagnostic threshold is debated.
- Existing criteria lack a definitive gold standard.
Purpose of the Study:
- To evaluate and compare current pathological criteria for HCM diagnosis.
- To assess the utility of myofibre disarray percentage, asymmetrical septal hypertrophy (ASH), subaortic plaque, and histologic HOCM index (HHI).
Main Methods:
- Analysis of 39 autopsy cases with cardiac myofibre disarray.
- Application of four pathological criteria: >5% septal myofibre disarray, ASH, subaortic plaque, and HHI.
- Comparison of criteria between groups with >5% (Group 1, n=27) and <5% (Group 2, n=12) myofibre disarray.
Main Results:
- Group 1 showed significantly higher ASH and myofibre disarray in ventricular free walls compared to Group 2.
- The histologic HOCM index (HHI) was the most frequent positive criterion in Group 1.
- A higher HHI was observed in patients who experienced sudden cardiac death.
Conclusions:
- No single pathological criterion currently serves as a gold standard for HCM diagnosis.
- The HHI shows promise, particularly in identifying cases associated with sudden death.
- Further refinement of pathological criteria for HCM is warranted.
Abstract:
This study aims to evaluate and compare the current pathological criteria for the diagnosis of hypertrophic cardiomyopathy (HOCM). The following criteria were applied to 39 autopsy patients whose hearts showed myofibre disarray: (i) disarray involving more than 5% of ventricular septal myofibres, (ii) asymmetrical septal hypertrophy (ASH), (iii) mirror-image subaortic plaque, and (iv) a positive histologic HOCM index (HHI). Group 1 (27 patients) with greater than 5% ventricular septal myofibre disarray were diagnosed as HCM, whereas group 2 (12 patients) had less than 5% disarray. The mean disarray value in group 1 was 52% compared to 1.2% in group 2. The two groups showed significant differences regarding ASH and in the amounts of myofibre disarray in the free walls of both ventricles. A new finding was that the histologic HOCM index was significantly higher in patients who died suddenly. The HHI was the commonest positive criterion in group 1, followed by ASH and a mirror-image endocardial plaque. None of the current imperfect pathological criteria for the diagnosis of HCM can be used as the 'gold standard'.