To the Editors:
The paper by Papadopoulos et al. 1 describes the failure of systolic left ventricular (LV) function in patients with idiopathic lung fibrosis (IPF).
Not much is known about LV systolic and diastolic function failure in IPF patients or its influence on rates of survival. In 1998, Vizza et al. 2 examined a large group of patients with advanced lung diseases and estimated that 6% of them had LV failure, in particular patients with primary pulmonary hypertension and Eisenmenger's syndrome. However, in a patient group with interstitial lung diseases (ILD) the proportion was lower and reached 3.6%.
In 2007, we studied LV systolic function in 18 patients with lung fibrosis and heavy respiratory insufficiency 3. The patients fulfilled the American Thoracic Society (ATS)/European Respiratory Society (ERS) criteria for lung transplantation. In this group there were nine patients with IPF, four patients with advanced allergic hypersensitivity alveolitis, three patients suffered from lung fibrosis in a course of connective tissue diseases and two patients had silicosis. The control group consisted of 22 patients with ILD that had been evaluated for lung transplantation, but did not meet all ATS/ERS criteria for intervention. Similarly to Papadopoulos et al. 1, we excluded patients with coexistent heart-circulation diseases or other diseases which might affect the LV function. The echocardiogram included two-dimensional examination with colour-doppler and pulsative parameters according to the recommendation of the American Echocardiography Society 4.
The presented spirometric and blood gas parameters were lower in our patient group in comparison to those presented by Papadopoulos et al. 1 (forced vital capacity (FVC): 37±15 versus 61±15 % predicted; arterial oxygen tension: 47±8 versus 62±6 mmHg (6.2±1.0 versus 8.3±0.8 kPa)). Also, the achieved distance in a 6-min walking test (6MWT) was shorter (255±180 versus 450±147 m). Unlike Papadopoulos et al. 1, we found substantial differences both in LV morphology and LV function between the study and the control groups. The end diastolic dimension of LV (4.4±0.7 versus 4.9±0.4 cm; p = 0.008), as well as LV volumes (end-systolic volume 26±12 versus 41±20 cm3; p = 0.01 and end-diastolic volume 56±29 versus 79±21 cm3; p = 0.02) were essentially different between the study and the control groups. Similarly to the study by Papadopoulos et al. 1, we did not state differences in the intraventricular septum diameter between the researched groups. We found positive correlations between the distance in 6MWT and variables connected with LV morphology. Similarities were also found between spirometric parameters (forced expiratory volume in one second and FVC) as well as the results of blood gas measurements and data obtained by echcardiogram estimation of LV. Consequently, it can be noticed that factors limiting activity in the end-stage ILD correlate with echocardiogram findings of LV in those patients.
Papadopoulos et al. 1 stated that the systolic function of the LV is preserved in patients with IPF. In our group, the systolic parameter of LV (estimated ejection fraction (EF)) was also satisfying (average EF 55.3±4.7%). However, we showed that patients with more advanced stages of pulmonary fibrosis present changes in the geometry of LV. Additionally, the size and the volume of LV correlate with parameters describing impairment of pulmonary function and activity in these patients. Therefore, although we did not estimate diastolic function of LV, we can assume that morphological changes of LV in patients with pulmonary fibrosis might also lead to the failure of the diastolic function of the LV. In our study, almost 70% of patients presented signs of pulmonary hypertension. Pulmonary hypertension can be the reason for changes in left ventricle geometry caused by an enlarged and overloaded right ventricle.
The correlation between echocardiogram parameters and the impairment of pulmonary function in patients with interstitial lung disease indicates that the impairment of left ventricular function is of major importance in patients with end-stage interstitial lung disease.
Statement of interest
None declared.
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