AKI after percutaneous edge-to-edge mitral repair tied to worse outcomes

Despite the lack of significant contrast use, nearly one in six patients undergoing transcatheter mitral valve repair (MitraClip) develop acute kidney injury (AKI), which is associated with device failure or other severe conditions, according to a study.

“Postprocedural AKI negatively affected survival and renal function at follow-up, with worse outcomes especially if mitral repair was suboptimal,” the researchers said. “A number of risk factors identified in the present report may help to optimize the management of these high-risk patients and to identify preventive preoperative measurements to be tested in the future.”

A total of 721 patients (mean age, 72±11 years; 28.3 percent women) who underwent MitraClip participated in this study. AKI was defined as an absolute or a relative increase in serum creatinine of >0.3 mg/dl or ≥50 percent, respectively, or the need for haemodialysis during index hospitalization.

The median estimated glomerular filtration rate (eGFR) was 43.7 ml/min/1.73 m² (interquartile range, 30.9–60.1) and was <60 ml/min/1.73 m² in 74.9 percent of the patients. Of the participants, 106 (14.7 percent) had AKI after MitraClip. [J Am Coll Cardiol 2020;76:2463-2473]

Independently, the following factors predicted AKI: baseline haemoglobin <11 g/dl (odds ratio [OR], 1.97; p=0.003), urgent procedure (OR, 3.44; p=0.003), and absence of device success (OR, 3.37; p<0.001). Outcomes were significantly worse for patients with AKI than for those without, which included a higher proportion of in-hospital bleeding events (3.8 percent vs 0.8 percent; p=0.011), 2-year all-cause mortality (40.5 percent vs 18.7 percent; p<0.001), and major adverse cardiac events (63.6 percent vs 23.5 percent; p<0.001).

Notably, the combination of AKI and significant residual mitral regurgitation (MR) after MitraClip resulted in even worse outcomes: 2-year all-cause mortality (50.0 percent vs 19.6 percent; p=0.001) and major adverse cardiac events (MACE; 70.0 percent vs 18.9 percent; p<0.001).

“Our incidence of AKI was slightly lower than previous smaller studies (ranging from 18–23.8 percent),” the researchers said. “This could be explained by different definitions of AKI and some differences in baseline characteristics (younger patients, less hypertension, lower N-terminal pro–B-type natriuretic peptide level, and STS score).” [Int J Cardiol 2013;169:e24-e25; Am J Cardiol 2018;122:316-322]

“However, the proportion [of patients] having AKI after MitraClip was in the range of other percutaneous interventions and, as demonstrated by others, lower than in surgical interventions,” they added. [J Am Coll Cardiol 2016; 68:1465-1473; EuroIntervention J Eur Collab Work Group Interv Cardiol Eur Soc Cardiol 2017; 12:2067-2074; EuroIntervention 2018;13:1645-1651]

The findings on the risk of 2-year all-cause mortality or MACE in AKI patients compared with those without was consistent with those from earlier studies. Significant residual MR also had been previously associated with the risk for future clinical events. [Int J Cardiol 2013;169:e24-e25; Am J Cardiol 2018;122:316-322; EuroIntervention 2014;9:1407-1417; Catheter Cardiovasc Interv 2013;81:609-617]

“AKI is a frequent and serious complication both in cardiac surgery and in catheter-based procedures, being associated with a worse prognosis even when slight deterioration of renal function occurs after the procedure,” the researchers said. [Circulation 2009;119:2444-2453; Ann Card Anaesth 2016;19:687-698; Am J Med 1998;104:343-348; J Am Coll Cardiol Intv 2018;11:1074-1083]

“Furthermore, the link between renal function and heart disease is widely known, and it is well-established that patients with CKD will have worse cardiovascular outcomes,” they added. [N Engl J Med 2004;351:1296-1305]