Results

Cohort characteristics

The 34 patients with a diagnosis of CF included in the study were 17 girls and 17 boys with a mean age of 9.94±4.97 years, while of the 37 healthy volunteers, whose mean age was 9.85±4.33; 18 were female and 19 male. No significant differences between the two groups were detected with regard to sex, age or weight (p>0.05). Testing for gene mutation was positive in 19 (55.8%) and the sweat test was positive in 30 (88.2%), with a mean score of 96.70±24.63 for the latter. Gastrointestinal and pulmonary involvement was present in 30 (88.2%) and 23 (94.1%) patients, respectively. In 16 (64%) of the 25 patients with a pulmonary involvement determined on the CT-scan, bronchiectasis was present. Of the CF patients, 4 (11.7%) had a history of more than 10 in-patient hospital admissions for pulmonary infection; the total number of such admissions was 5-10 in 10 (29.4%) and was less than 5 in 15 (44.1%) patients. Colonization by Pseudomonas aeruginosa was detected in 13 (38.2%) and that by Staphylococcus aureus in 11 (32.3%). Of 19 patients who were subjected to respiratory function testing, 13 (68.4%) showed an abnormal result; the remaining 6 (31.6%) were unremarkable in this regard.

Echocardiographic Findings

M-mode and Doppler echocardiography results are summarized in Table 1. While no difference could be detected between the patients and volunteer groups with regard to LV measurements IVSd, IVSs, LVPWd, LVPWs, EF and FS, there as a significant difference between them in LVDd and LVDs measurements. Pulmonary artery systolic pressure (PAPs) was significantly higher in the CF group compared to the controls (32.50±4.09 and 28.96±2.82 mmHg, respectively; p<0.001). Diastolic pulmonary artery pressure (PAPd) was 10.57±3.68 mmHg in the patients and 9.00±2.08 mmHg in the control patients, with no statistically significant difference detected. Similarly, no statistically significant difference could be evidenced between the two groups in the Doppler echocardiography parameters E-wave, A-wave, E/A ratio and E/e’ ratio.
Color TDI results are summarized in Table 2. Color TDI measurement of LV parameters also evidenced some systolic and diastolic dysfunction. When compared to the controls by TDI, CF patients had shorter TST (343.7±37.5 ms vs. 367.8±38.6 ms respectively, p=0.009), EF (260.7±32.8 ms vs. 288±38.7 ms, p=0.002) and increased MPI (0.32±0.04 vs. 0.28±0.05, p=0.001). Interventricular septal TST was reduced in CF patients (341.1±38.6 ms vs. 361.1±3.2 ms in controls, p=0.027), ET was relatively shortened (256.9±35 ms vs. 282.2±33.2 ms, p=0.002), IVRT lengthened (47.6±5.8 ms vs. 44.4±5.3 ms, p=0.017) and MPI was increased (0.33±0.04 vs. 0.28±0.03, p=0.000).

Speckle Tracking Echocardiography

LV longitudinal myocardial strain measurements indicated the following reductions in segmental circumferential myocardial strain compared to the control group: apical septal (-20.0±4.8 vs. -23.4±5.8, p=0.015), apex (-20.0±4.8 vs. -23.4±5.8, p=0.003), AC3 chamber mid inferolateral (-18.7±4.1 vs. -22.2±5.6, p=0.004), basal anteroseptal (-17.8±3.9 vs. -21.4±5.7, p=0.004), mid inferior (-18.7±4.1 vs. -21.5±6.2, p=0.044), apical inferior (-19.9±4.3 vs. -22.2±4.4, p=0.027), mid anterior (-18.8±3.9 vs. -21.7±5.9, p=0.025). Global strain and total global strain values did not appear to be different (Table 3). Circumferential myocardial strain measurements of the LV wall showed significant reductions in CF patients compared to controls in the basal inferior (-17.9±7.2 vs. -21.2±6, p=0.049), mid inferior (-17.8±7 vs. -23.9±6.6, p=0.001) and apical anterior (-21.6±6.6 vs. -27.5±5.2, p<0.001) segments. No difference was observed between global strain and total global strain values (Table 4). Longitudinal strain rate measurements of CF patients by segment, compared to the controls by segment, were as follows: in A4C mid anterolateral (-1.5±0.3 vs. -2.0±0.5, p=0.001), in A3C basal inferolateral (-1.6±0.3 vs. -1.9±0.6, p=0.030), in A2C mid inferior (-1.7±0.4 vs. -2.1±0.7, p=0.010), apex (-1.3±0.2 vs. -1.5±0.5, p=0.023), apical anterior (-1.4±0.3 vs. -1.7±0.6, p=0.041). Circumferential strain rate measurements were also lower in CF patients than in healthy controls in the following parameters: in basal view, in the basal anteroseptal (-2.0±0.4 vs. -2.4±0.5, p=0.003) and basal anterolateral (-1.6±0.4 vs. -2.0±0.7, p=0.040); in the medial view, in the mid anterior (-1.7±0.5 vs. -2.0±0.5, p=0.039), mid inferolateral (-1.7±0.4 vs. -2.0±0.6, p=0.035) and mid inferoseptal segments (-1.7±0.4 vs. -1.9±0.3, p=0.012) (Tables 3,4).