{'fraction_non_alphanumeric': 0.05339805825242718, 'fraction_numerical': 0.05218446601941747, 'mean_word_length': 4.058282208588957, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Changes in renal function over time in patients with cardiac resynchronisation therapy.

QUESTION UNDER STUDY
Cardiac resynchronisation therapy (CRT) with defibrillator back-up (CRT-D) is widely used in selected patients with moderate/severe heart failure. Renal failure is common in these patients. Data on the impact of CRT on renal function are controversial and limited by short follow-up. The aim of this study was to describe changes in glomerular filtration rate (GFR) from baseline compared with 1 and 2 years after CRT implantation.


METHODS
A total of 284 CRT-D patients with creatinine levels at baseline and after 1 year were identified in two prospective registries. In 149 patients, levels after 2 years were available. GFR in ml/min/1.73 m2 was estimated with the Modification Diet in Renal Disease equation and patients stratified into GFR stages 1 to 4.


RESULTS
The population was predominantly male (75%), mean (± standard deviation) age was 61 ± 7 years and ejection fraction 24% ± 8 %. GFR was 63 ± 24 ml/min/1.73 m2 at implantation and 60 ± 24 ml/min/1.73 m2 after 1 year (p = 0.26). At the 2-year follow-up, GFR had decreased from 60 ± 21 to 56 ± 21 ml/min/1.73 m2 (p = 0.04). Mean GFR decreased in stages 1 and 2, remained stable in stage 3 and improved in stage 4 patients. After 2 years, GFR had decreased ≥10 ml/min/1.73 m2 in 42%, but improved in only 15% (p = 0.04).


CONCLUSIONS
Overall, mean GFR in CRT-D patients decreases at 1 and 2 years after implantation, depending in part on the initial degree of renal function. However, the chance of further substantial deterioration (≥10 ml/min/1.73 m2) is considerable.