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Functional and histopathologic correlation in patients with dilated cardiomyopathy: an integrated evaluation by
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In dilated cardiomyopathy, collagen fiber proliferation significantly correlates with reduced heart contractility. This histologic finding may be a key factor in worsening cardiac function in affected patients.
Area of Science:
- Cardiology
- Pathology
- Biomedical Engineering
Background:
- Dilated cardiomyopathy (DCM) is characterized by impaired left ventricular function.
- Understanding the relationship between cardiac structure and function is crucial for managing DCM.
- Histologic changes in myocardial tissue may offer insights into disease progression.
Purpose of the Study:
- To correlate left ventricular (LV) hemodynamic function with histologic features in patients with DCM.
- To identify specific histologic markers associated with functional deterioration in DCM.
- To investigate the role of collagen fiber proliferation in DCM pathophysiology.
Main Methods:
- Endomyocardial biopsies were obtained from DCM patients during cardiac catheterization.
- Hemodynamic indexes including ejection fraction and stress-volume relations were assessed.
- Histologic findings (myofiber disarray, hypertrophy, etc.) were semiquantitatively graded.
- Multivariate analysis, including principal component and Fisher's discriminant analysis, was employed.
Main Results:
- Ejection fraction was lower in patients with significant collagen fiber proliferation.
- Hypertrophy of myofibers correlated with increased collagen fiber proliferation.
- Fisher's discriminant analysis distinguished between patients with and without significant collagen fiber proliferation.
- Patients with collagen fiber proliferation showed reduced contractility and elevated afterload.
Conclusions:
- Proliferation of collagen fibers is a significant histologic finding in DCM.
- Collagen fiber proliferation is associated with impaired left ventricular contractility and elevated afterload.
- Collagen fiber proliferation may play a pivotal role in the functional deterioration observed in dilated cardiomyopathy.
Abstract:
To correlate left ventricular function and histologic features in patients with dilated cardiomyopathy, precise indexes of hemodynamics and semiquantitative histologic data were combined for multivariate analysis. Right endomyocardial biopsy was performed at the time of cardiac catheterization. Five hemodynamic indexes were used for functional assessment: ejection fraction, ratio of end-systolic stress to volume index, end-diastolic stress, time constant (T) of left ventricular pressure fall, and end-systolic stress. Six histologic findings (disarray of myofibers, hypertrophy of myofibers, scarcity of myofibrils, nuclear changes of myofibers, vacuolization of myofibers and proliferation of collagen fibers) were graded from (-) to (4+). Each finding was assigned to category (-) or (+) according to the absence or presence of significant abnormality. Ordinary statistical analysis revealed that, although ejection fraction was lower in category (+) for proliferation of collagen fibers, ratio of end-systolic to volume index was reduced for category (+) of hypertrophy of myofibers. A significant correlation was present between hypertrophy of myofibers and proliferation of collagen fibers by Spearman rank correlation. When principal component analysis was applied to the hemodynamic data, two principal components could be extracted. Fisher's discriminant analysis could clearly differentiate two categories (-) and (+) in the semiquantitative histologic finding of proliferation of collagen fibers. The analysis indicated that contractility was reduced with elevated afterload in that category (+). Thus, proliferation of collagen fibers may play a pivotal role in deteriorating contractility in patients with dilated cardiomyopathy.