Acute kidney injury remains a ‘relatively common’ complication of TAVI (Transcatheter Aortic Valve Implantation) procedures and is associated with significant mortality even in less comorbid patients, Australian research has concluded.

Drawn from Victorian registry data, the study is notable for showing the complication is continuing to occur despite advances in cardiac surgery practice, with an overall incidence of 6% since 2015.

The finding underscores the importance of improving pre-procedural acute kidney injury (AKI) risk stratification for patients, as well as the development of preventative and treatment strategies, say the authors.

A total of 2564 patients undergoing TAVI from 2008 to 2023 included in the Alfred-Cabrini-Epworth (ACE) TAVI Registry were analysed for the study, led by senior author and interventional cardiologist Professor Dion Stub.

Some 163 (6.4%) developed AKI over this time, although incidence fell from 9.7% in the first seven years to 6% from 2015 onwards.

While these rates were lower than reported in some recent overseas studies, AKI was still occurring with relatively high frequency, they wrote in in Heart, Lung & Circulation (link here).

AKI was also an independent predictor of 30-day (adjusted OR: 6.07, p<0.001) and 12-month (adjusted OR: 3.01, p=0.002) mortality, an association that remained consistent when excluding TAVIs performed prior to 2015, according to the authors.

“We are one of the first large, multi-centre registries to present longitudinal data examining the influence of TAVI evolution on AKI,” they said.

“Our work establishes that while incidence of AKI is falling, it remains a relatively common complication with significant morbidity and mortality even in contemporary practice patients.”

Moreover, the data revealed that baseline renal function and procedural characteristics were more powerful predictors of AKI than traditional cardiovascular risk factors in a less comorbid population.

On multivariable analysis, independent predictors of AKI were male sex, congestive cardiac failure, estimated glomerular filtration rate 30–59 and particularly rate <30.

Others included non-femoral access, bleeding, and contrast volume.

Based on these results, the authors strongly advocated for patients at high risk of AKI to have femoral access, avoidance of GA and minimisation of contrast volume where possible.

Interestingly, the use of self-expanding (SE) valves was associated with 1.6 times higher odds of AKI, a finding that added to the small but growing body of literature that demonstrated an association between the two.

Nevertheless, the science behind this apparent link was largely unexplored and the relationship lost significance in multivariate models excluding older TAVIs, the authors said.

“This is likely attributable to marked improvements in procedural technique, SE valve technology and delivery device stability,” they wrote.

“The introduction of cusp overlap view, which elongates the left ventricular outflow tract allowing for more precise control of the prosthesis depth, has seen promising results in reducing post-procedural conduction abnormality—a possible contributor to AKI.”

“Furthermore, iterative evolution in SE valves such as the addition of an outer pericardial tissue wrap designed to enhance sealing at the level of the aortic annulus and the ability for complete recapture and repositioning has improved overall outcomes with these bioprostheses, again possibly reducing AKI.”