3.1 Baseline characteristics
The baseline demographic and metabolic characteristics of the entire CKD population (n=60) are shown in Table 1 . The median age of the CKD patients was 63 years and most of them were males (70%). Most of the CKD patients had an established history of hypertension (88%) and 28% were diagnosed with diabetes. The underlying etiology of CKD was defined in appx 75% of the patients with various diagnoses. Only 57% of the patients were treated with a RAAS blocker. The median value of eGFR was 30.5 ml/min/1.73 m2 and 24-hr urine protein 900 mg. There was no statistically significant difference between younger and older CKD patients in eGFR (32.9±18.2 vs 31.5±12.9ml/min/1.73 m2, p=0.732) and 24hr urine protein [median 1134 (IQ range 498, 3000) versus 400 (IQ range 159, 2356), p=0.136].
3.2 Comparison between younger CKD patients and healthy controls (Table 2)
There were no significant differences in age, gender and body mass index between the two groups (p=NS). Patients with CKD had higher E/e’ ratio (7.80±2.71 vs 6.06±1.37, p=0.019 Bonferroni correction), LVMI (114.7±41.1 vs 89.6±21.2, p=0.017Bonferroni correction) and relative wall thickness (0.47±0.08 vs 0.40±0.06, p=0.031Bonferroni correction) and lower E’ (10.6±2.6 cm/s vs 2.3±2.9 cm/s, p=0.045Bonferroni correction) compared to healthy controls.
3.3 Comparison between CKD patient subgroups i.e. <60 versus ≥60 years old (Table 2)
There were no significant differences in gender or body mass index between the two groups (p=NS).Older CKD patients had higher systolic BP(143±21mmHg vs 130±18 mmHg, p=0.023 Bonferroni correction) and lower E/A (0.80±0.19 vs 1.03±0.33, p=0.007 Bonferroni correction) and E’ (8.5±1.8cm/s vs 10.6±2.6 cm/s, p=0.003 Bonferroni correction) compared to younger CKD patients. None of the aforementioned differences remained significant after adjustment for the difference in age between the two groups (p=NS for all).
3.4 Effects of dipyridamole infusionin CKD subgroups and healthy controls (Table 3)
CFR was higher in healthy controls compared to both younger (3.93±1.25 versus 3.1±0.75, p=0.009, Bonferroni correction) and older CKD patients (3.93±1.25versus 2.89±0.88, p<0.001,Bonferroni correction). There was no significant difference in CFR between younger and older CKD patients (p=1.000, Bonferroni correction). Dipyridamole caused a significant increase in Sm, Sl, E’and a decrease in GLS in all groups (p<0.05 for all). LVEF was significantly increased in healthy controls and younger CKD patients while UNTWIST was significantly decreased in healthy controls and older CKD patients (p<0.05 for all) following dipyridamole administration. Dipyridamole significantly decreased E/A ratio only in younger CKD patients (p<0.05). Dipyridamole-induced changes did not differ significantly among the 3 studied groups (RM ANOVA, p=NS for all).