Blog entry by Meguid El Nahas
This article by Huang and colleagues from Taiwan appeared in the January 2011 issue of JASN.
It shows that patients undergoing coronary artery grafting/surgery who have pre-operative proteinuria are at a considerable higher risk to develop post-operative AKI. Odds ration from 1.66, 2.30 to 7.29 for mild, moderate and severe proteinuria respectively. This was independent of the presence of diabetes.
This article adds to the growing list of observations, including those made by the CKD Collaborative consortium and published in KI 2011, showing that proteinuria is an independent risk factor for the development of AKI.
Most of these studies overlook the following:
1. That proteinuria/albuminuria in elderly individuals is a marker of underlying vascular pathology and endothelial dysfunction. Therefore the worst the underlying CVD the higher the albuminuria. It is therefore not surprising that those with the most severe underlying atherosclerosis and CVD have the higher risk of AKI!
2. Most of these studies, including the one by Huang et al, does not take into account that elderly individuals with proteinuria are often treated with inhibitors of the RAAS. These agents, whether they are ACE inhibitors or angiotensin receptor blockers, are potentially nephrotoxic and would increase the risk of post-operative AKI.
The learning point here is:
STOP ACEinhibitors/ARBs well before any high risk surgery as these agents could increase the risk of AKI and the associated morbidity and mortality!