Wednesday, June 3, 2009

Renal stents for preservation of renal function with atherosclerotic renal artery stenosis

The annals has an article this week on renal stents and again they fail.

Stent Placement in Patients With Atherosclerotic Renal Artery Stenosis and Impaired Renal Function

They randomized 140 patients with GFR <>50% stenosis (CT angio, MRA or digital subtraction angiography) with in 1 cm of the origin of the renal artery. They also excluded patients with uncontrolled blood pressure (>140/90) this was done because if patients randomized to medical management developed uncontrollable blood pressure they could cross over and receive a stent.

The end point was a persistant 20% reduction of GFR by Cockcroft-Gault for more than a month.

Results: No significant difference between the two treatment strategies.

The Kaplan-Meier curves confirm this. The top graph is the primary outcome and the bottom graph is primary outcome plus death:
Renal angioplasty resulted a variety of complications:

Two patients in the stent group died of procedure-related causes within 30 days after stent placement. In 1 of the patients, embolization of a perforated renal artery was required; the patient subsequently developed pulmonary edema and needed mechanical ventilation, and died of a massive ischemic stroke 3 days later. The second patient had perforation of a renal artery branch; the artery was embolized, but despite re-intervention, the patient went into hypovolemic shock and experienced the acute respiratory distress syndrome, and died of multiorgan failure after 1 week.

The most common complications after stent placement were minor and mainly consisted of hematoma at the puncture site (11 patients [17%]). In 1 of these patients, secondary infection in the groin required surgical reconstruction. The patient thereafter developed end-stage renal failure, pulmonary edema, and heart failure and died 6 months after the procedure. In 2 other patients, stent placement was complicated by false aneurysm of the femoral artery. Injury to the kidney or renal artery occurred in 5 patients; however, this was never associated with loss of renal function and additional intervention was never required.

One patient in the stent group who had repeated angiography required permanent dialysis after cholesterol embolism.

So another negative trial of renal artery revascularization. We are still waiting for the publication of ASTRAL, a much larger and more definitive trial. CORAL is another trial which is ongoing and will shed further light on this subject.
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