Author + information
- Goktug Savas, MD∗ ( and )
- Nihat Kalay, MD
- ↵∗Department of Cardiology, Erciyes University School of Medicine, 38039 Kayseri, Turkey
We have read with great interest the report by Murphy et al. (1) who used data from the CORAL (Cardiovascular Outcomes in Renal Atherosclerotic Lesions) study to examine the treatment effect of the renal artery stent procedure compared with medical therapy alone on the basis of stenosis severity, level of systolic blood pressure elevation, and translesion pressure gradient. The authors failed to demonstrate a significant difference in outcomes on the basis of the examined variables. Moreover, some issues need further clarifications and it may be pertinent to discuss them.
In our opinion, the determined endpoints may not be suitable for investigating the effects of renal artery stenting. Why do we primarily expect that the treatment of renal artery stenosis will have a beneficial effect on stroke, acute myocardial infarction, or death from cardiovascular causes? These adverse events may be affected by many factors such as arrhythmia, baseline left ventricle function, variation in medical therapy, or familial predisposition. Although no one denies the importance of these outcomes in a clinical care setting, there is however a more important question: Does renal artery stenting confer improvement in renal functions, lower blood pressure, or prevent renal deaths? It may be more appropriate to evaluate renal stenting results with respect to narrowed end points.
In a previous study, Harden et al. (2) reported that stabilization or improvement in renal function, which was defined as a 20% change in serum creatinine value after renal stent placement, was quite frequent (69%). In our opinion, improvement in kidney function after the renal stent procedure should be expected among patients with severe renal artery stenosis but without severe renal dysfunction. Also, in the CORAL study, patients with a serum creatinine level ≤1.6 mg/dl tended to benefit from stent therapy (3). However, in the present report, the effects of the renal stent procedure on kidney functions or the primary endpoints among these subgroups were unknown. Thus, a new assessment requires detailed analyses that weigh the benefits of renal artery stenting with respect to renal outcomes or primary endpoints among subgroups who have extreme pressure gradients or stenosis severity with preserved kidney function.
Please note: Both authors have reported that they have no relationships relevant to the contents of this paper to disclose.
- American College of Cardiology Foundation