Two questions arise when an arteriosclerotic renal artery stenosis is identified. First, is it a contributing factor to the patient’s hypertension or renal insufficiency? Second, if stenosis is a contributing factor and an operative intervention is deemed appropriate, is an open surgical procedure or endovascular procedure preferred?

Historically, when open surgical procedures were the only means available to revascularize a kidney, considerable time and resources were spent to ensure that preoperative diagnosis was accurate. Because of the thoroughness of these preoperative studies, outcomes from centers of excellence regarding hypertension after open surgery for renal artery arteriosclerotic disease were relatively good. In experienced surgeons’ hands, cure rates were in the 15% to 30% range, significant improvement occurred in 50% to 75%, and mortality rates ranged from 0% to 6%. Mortality in these cases was often attributed to patients undergoing concomitant aortic surgery, which skewed the risks of the accompanying renal artery intervention. Randomized, controlled trials comparing open surgical treatment to medical therapy of arteriosclerotic renal artery stenotic disease are nonexistent.

There was a fourfold increase in endovascular interventions for renal artery disease in the United States between 1996 and 2005. Many assume that endovascular treatment of renal artery stenotic disease is a simple procedure requiring minimal skill. That is not the case. In fact, the appropriateness of the commonplace endovascular treatment of renal artery disease has been questioned. A detailed review of the CORAL, ASTRAL, STAR, DRASTIC, Newcastle Renal Artery Stenosis Group, Hospital Broussais, and RAOOD clinical trials^∗ underscores this concern. These studies compared endovascular renal artery intervention to medical management (five trials) or surgery (one trial). In none of these trials were clear advantages ascribed to endovascular therapy. Complication rates accompanying endovascular treatments ranged from 10% to 40%, and the mortality rate was not zero. The design and conduct of these trials had many flaws, yet their influence on clinical practice has persisted. Clearly, a more rigorous set of indications and contraindications for endovascular and open surgical renal artery interventions are needed.

Conditions in Favor of Open Renal Artery Revascularization

Open revascularization should be considered if an endovascular procedure would require small-diameter (<6 mm) or long (>15–20 mm) stents. Early thrombosis or restenosis is likely using stents having these dimensions. This is a particular issue when multiple small renal arteries, especially accessory renal arteries, require reconstruction.

Stenotic disease affecting renal arteries with very early bifurcations may be treated best by an open procedure. Such an anatomic finding affects 14% of patients and limits effective renal artery angioplasty and stenting because of an attendant risk of segmental branch occlusions. Segmental branch occlusions occur as a consequence of the stent itself as well as disruption of the underlying plaque.

Patients exhibiting luminal thrombus or ulcerated renal plaques, with an attendant risk of distal atheroembolization, are better treated with an open procedure in which temporary occlusion of the renal artery offers a means of protecting the kidney. A subtler suggestion that a patient may be at high risk for atheroembolism includes visualization of retained contrast along the perirenal aortic wall, which indicates a granular lining of superficial arteriosclerotic material. This material often embolizes with the least amount of catheter or guidewire trauma.

Atheroembolism is clinically significant in 2% to 10% of renal artery endovascular procedures. The incidence of this complication may be even higher, given that endovascular filters capture debris in more than 60% of patients undergoing renal artery angioplasty. Devices to trap this material can decrease the risk for this complication. However, the distance of unaffected artery distal to the intended landing site of the stent must be greater than 1 to 2 cm for a filter device to be placed. A branch occlusion or filter entrapment can occur if the unaffected artery is not long enough.

Concomitant aortic surgery may be a reason to pursue open renal revascularization, rather than an endovascular approach. An open renal artery reconstruction is favored in certain patients with an aortic aneurysm to be treated by an aortic endograft. This is the case if a renal artery stent would interfere with the aortic endograft landing zone or if a stent would cause subsequent difficulty in cannulating the renal artery if suprarenal aortic graft fixation was to be accomplished. Similarly, an open renal artery reconstruction is recommended in patients having pararenal aortic occlusion, in that femoral artery access to the renal artery for an endovascular procedure is not possible. Although a brachial artery approach may be used in this setting, accessing a stenotic renal artery using long sheaths by this route would be challenging and can lead to injury of the brachial artery. Simultaneous open aortic and renal reconstructions would be appropriate in such cases.

Failure of a complex renal artery angioplasty with stenting or repeated endovascular interventions for recurrent stenotic disease are common indications for an open renal revascularization. The outcome of an open surgical intervention in this setting is not as good as if it were the initial therapy, and the risk of nephrectomy in this setting is many times greater than with an open renal revascularization as a primary intervention.

Young patients (younger than 50 years) who could undergo either an endovascular or open renal revascularization might benefit from an open procedure if they do not have coexisting illnesses that present a prohibitive operative risk. Advocating open renal reconstructions in younger patients is based on the greater benefit afforded them in the long term, in contrast to the less salutary long-term outcomes accompanying endovascular therapy.

The RAOOD trial is the only recent randomized, controlled trial that has compared open renal artery revascularization to endovascular treatment. The trial, published in 2009, included 29 renal arteries revascularized by open surgery and 28 renal arteries treated by endovascular techniques. No procedural mortality occurred in either group. Endovascular-related morbidity was 4%, compared to 13% in the open surgical group. Both interventions improved renovascular hypertension and preserved or improved kidney function. However, primary patency at 4 years was 68% in the endovascular group versus 88% in the open surgical group. Cumulative (primary and secondary) freedom at 4 years from recurrent renal artery stenosis (>70%) was 90% of the surgical group versus 80% in the endovascular group. Although this was a small study and its design was subject to criticism, it appears that open renal revascularization in experienced hands is a safe procedure and provides benefits that are longer lasting.

Restenosis after renal angioplasty and stenting is not benign. A large retrospective review from West Virginia on the outcomes of 122 renal artery stents associated with symptomatic restenosis found that independent of any treatment of the recurrent stenosis, 23% progressed to renal failure and 28% had no benefit or a worsening of their hypertension. This was particularly problematic in patients with a single functional kidney and a previously thrombosed renal artery stent.

Only gold members can continue reading. Log In or Register to continue

Share this:

• Click to share on Twitter (Opens in new window)
• Click to share on Facebook (Opens in new window)

Related

Related posts:

1. Physiologic and Noninvasive Studies to Document Severity and Extent of Aortoiliac Occlusive Disease
2. Surgical Treatment of Lymphedema
3. Arteriographic Evaluation of Cerebrovascular Disease
4. Endovascular Management of Isolated Iliac Artery Aneurysms

Stay updated, free articles. Join our Telegram channel

Join