Cath Lab Digest

In a recent issue of the Journal of Vascular Surgery, Modrall et al¹ published a paper on a retrospective clinical study of predictors of a favorable blood pressure (BP) response to RAS. The patient cohort was comprised of 149 patients receiving RAS between the years 2000 and 2008. The bottom-line results (in a multivariate analysis) pointed to 3 pre-operative clinical variables that may turn out to be useful predictors of a favorable BP response to RAS: 4 or more anti-hypertensive medications, diastolic BP ≥90 mm Hg, and clonidine use. All others were deemed to be non-responders.

Interestingly, in 86 out of the 149 patients, renal volume was estimated on the basis of pre-procedure CT or MR scans using the formula kidney length x width x depth divided by 2. The study uncovered that among patients with a 3-drug hypertension, a larger ipsilateral kidney (volume ≥150 cm³) increased the BP response rate more than threefold when compared with patients with smaller kidneys (63% vs. 18% BP response rate).

I think most would agree RAS – and renal artery revascularization in general – have gone through a prolonged period of “funk,” where uncertainty, equivocal data, and negative trial results have reigned supreme. To me, it still makes sense to open up (stent) tightly narrowed renal arteries in the majority of cases, and (for the most part) have continued to do so. But scientific evidence has lagged far behind “intuitive logic” in this important area of interventional medicine. This paper by Modrall et al should be regarded as a beacon of brightness and hope in an otherwise dark landscape. The data on kidney morphology (volume) is particularly interesting and somewhat intriguing, adding another important parameter that will hopefully prove helpful at the time of clinical decision-making.

I’d be keen to hear reactions and personal views on the matter…

References

1. Modrall JG, Rosero EB, Leonard D, et al. Clinical and kidney morphologic predictors of outcome for renal artery stenting: Data to inform patient selection. J Vasc Surg 2011;53(5):1282–1290.

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Dr. Frank J Criado is a Board-Certified Vascular Surgeon and Endovascular Specialist at the Union Memorial Hospital-MedStar Health in Baltimore, Maryland – USA.

Dr. Criado is widely acknowledged to be a pioneer in endovascular therapy, with a 20-year + interventional experience. He has contributed extensively to the literature with more than 100 peer-reviewed published articles – mostly on various vascular and endovascular subjects, and Editor-in-Chief of Vascular Disease Management (VDM). He has also been active in clinical research, with a major focus on aortic stent-graft and carotid interventions, and endovascular technologies in general. He was the National Principal Investigator (P.I.) for the Medtronic Talent AAA clinical trials in the U.S., and a member of the Executive Committee for the Medtronic Valor Thoracic trial.

He is a founding member and immediate past President of the International Society of Endovascular Specialists (ISES), founder and current President of the endovascular surgery society of Latinamerica (CELA), and a member of all major U.S. and international vascular and endovascular societies. He is a Fellow of the American College of Surgeons (FACS) and of the Society of Vascular Medicine (FSVM), and a member of the Board of Directors of the Society for Vascular Surgery (SVS).