Renal Artery Angioplasty Technique

Updated: Jun 20, 2016
  • Author: Vibhuti N Singh, MD, MPH, FACC, FSCAI; Chief Editor: Kyung J Cho, MD, FACR, FSIR  more...
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Technique

Renal Artery Angioplasty and Stenting

The technique for renal artery angioplasty and stenting is described and illustrated below.

For a percutaneous transluminal renal angioplasty (PTRA), the patient is sterilely prepared and draped, conscious sedation is employed, a local anesthetic (lidocaine 1% or 2% solution) is infiltrated at the femoral access site, an arterial sheath is placed in the femoral artery, and the renal guide catheter is advanced over a 0.035-in. guide wire under fluoroscopic guidance. After the tip of the guide catheter is positioned at the ostium of the renal artery, an angiogram (see the images below) is obtained.

Percutaneous transluminal renal angioplasty in mid Percutaneous transluminal renal angioplasty in middle-aged woman with malignant renovascular hypertension. This preprocedural right renal arteriogram was obtained after sterile preparation and draping of the patient, conscious sedation, infiltration of local anesthetic (lidocaine 1% or 2% solution) at the femoral access site, placement of an arterial sheath in the femoral artery, and advancement of the renal guide catheter over a 0.035-in. guide wire under fluoroscopic guidance. After the tip of the guide catheter is positioned at the ostium of the renal artery, an angiogram (as shown here) is obtained. After the guide wire is removed, the proximal end of the catheter is connected to a manifold, and 4-8 mL of contrast is manually injected during cineangiographic recording. Once obtained, the image may be played over and over in a loop, or a particular frame may be saved for review during angioplasty. An intravenous antithrombotic agent, usually heparin, is administered before the clinician proceeds with angioplasty. The patient's activated clotting time is monitored.
Preangioplasty angiogram obtained in a young woman Preangioplasty angiogram obtained in a young woman with malignant hypertension shows tight stenosis in the middle segment of the right renal artery. Its appearance is consistent with that of fibromuscular dysplasia, for which angioplasty is the procedure of choice and for which stenting is usually not indicated. Intra-arterial nitroglycerine, 300 mcg, was given without any change in the appearance of the stenosis (which differentiates it from spasm).

After the guide wire is removed, the proximal end of the catheter is connected to a manifold, and 4-8 mL of contrast is manually injected during cineangiographic recording. Once an image is obtained, it may be played over and over in a loop, or a particular frame may be saved for review during angioplasty. An intravenous (IV) antithrombotic agent, usually heparin, is administered before the clinician proceeds with angioplasty. The patient's activated clotting time is monitored.

A 0.018-in. guide wire is advanced through the 6-French renal guide across the renal stenosis. A small torque device is used over the proximal segment of the guide wire for steering, while a small terminal bend is created by hand over the distal end of the guide wire before it is introduced into the guide catheter. Passage of the guide wire is monitored by using fluoroscopy and injections of small amounts of contrast agent. Occasionally, a combination of torque and forward pressure is required to cross the lesion. In addition, in tight lesions, the balloon catheter is sometimes advanced and used as a support for passage of the guide wire. (See the image below.)

A 0.018-in. guide wire is advanced through the 6F A 0.018-in. guide wire is advanced through the 6F renal guide across the ostial right renal stenosis. A small torque device is used over the proximal segment of the guide wire for steering, while a small terminal bend is created by hand over the distal end of the guide wire before it is introduced into the guide catheter. Passage of the guidewire is monitored by using fluoroscopy and injections of small amounts of contrast agent. Occasionally, a combination of torque and forward pressure is required to cross the lesion. In addition, in tight lesions, the balloon catheter is sometimes advanced and used as a support for passage of the guide wire.

A 6-mm × 18-mm balloon is positioned across the lesion by carefully advancing it over the guide wire. The balloon is prepared before it is loaded over the wire by connecting its proximal balloon port to an inflating device that contains a 50:50 solution of contrast agent and sterile saline and then by drawing negative pressure to extrude any air bubbles. The inflating device is left in negative pressure while the balloon is advanced with one hand and the guide wire is held with the other.

The balloon is advanced beyond the distal end of the guide catheter, which is gently pulled back, and the balloon is straddled across the stenosed segment. A small amount of contrast agent is injected to confirm proper positioning of the balloon. (See the image below.)

A 6-mm × 18-mm balloon is positioned across the le A 6-mm × 18-mm balloon is positioned across the lesion by carefully advancing it over the guide wire. The balloon is prepared before it is loaded over the guide wire by connecting its proximal balloon port to an inflating device that contains a half-and-half solution of contrast agent and sterile saline and then by drawing negative pressure to extrude any air bubbles. The inflating device is left in negative pressure while the balloon is advanced with one hand and the guide wire is held with the other. The balloon is advanced beyond the distal end of the guide catheter, which is gently pulled back, and the balloon is straddled across the stenosed segment. A small amount of contrast agent is injected to confirm proper positioning of the balloon.

The balloon is inflated by increasing the pressure with the inflation device to several atmospheres of pressure (usually 4-8 bars). The mixed solution of contrast agent and saline in the inflation device gradually moves into the balloon. As the balloon expands, it becomes visible under fluoroscopy (see the images below). The balloon is held up for several seconds to apply circumferential pressure on the stenosed arterial segment and then deflated and gradually pulled back into the guide catheter.

The balloon is inflated by increasing the pressure The balloon is inflated by increasing the pressure with the inflation device to several atmospheres of pressure (usually 4-8 bars). The mixed solution of contrast agent and saline in the inflation device gradually moves into the balloon. As the balloon expands, it becomes visible under fluoroscopy, as shown. The balloon is held up for several seconds to apply circumferential pressure on the stenosed arterial segment and then deflated and gradually pulled back into the guide catheter.
Fluoroscopic image shows an inflated percutaneous Fluoroscopic image shows an inflated percutaneous transluminal angioplasty (PTA) balloon in the midright renal artery over the guid ewire. In this case, a Judkins right 4 (JR4) guide was used to access the right renal artery via a right femoral approach. The balloon was left inflated for several seconds, then deflated and pulled out. Additional intra-arterial nitroglycerine was infused.

After PTRA and after the balloon catheter is removed but while the guide wire is still retained, angiography is performed to evaluate the success of the procedure (see the images below).

Angiogram obtained after percutaneous transluminal Angiogram obtained after percutaneous transluminal angioplasty and after the balloon catheter is removed but while the guidewire is still retained shows increased luminal diameter at the stenotic segment. However, the segment appears to be at least 50% narrowed. Flow into the renal artery from the aorta is increased. The vascular wall shows no clear dissection. No filling defect (which may represent clot) is visible. Distal flow into the branches of the right renal artery is brisk, with good tissue flush.
Angiogram obtained after percutaneous transluminal Angiogram obtained after percutaneous transluminal angioplasty and after the balloon catheter was removed shows a good result with residual stenosis of less than 20% at the previously stenosed site. Flow into the renal artery from the aorta is increased. The vascular wall shows no clear dissection. No filling defect (which may represent clot) is visible. Distal flow into the branches of the right renal artery is brisk, with good tissue flush.

Preparation of a stent-balloon catheter is similar to that of a balloon catheter; however, no negative pressure is created insertion into the guide catheter. The stent-balloon catheter is advanced over the guide wire through the guide catheter beyond the distal opening and across the lesion. The stent is positioned over the lesion; placement is confirmed with the injection of a small amount of contrast material through the guide. The guide catheter is pulled back on the wire a little to allow the proximal edge of the stent to be slightly in the aorta. Before the stent balloon is inflated, the guide catheter is pushed upward to straighten the stent and wire in the proximal portion of the renal artery. (See the image below.)

A stent-balloon catheter is prepared in a manner s A stent-balloon catheter is prepared in a manner similar to the balloon catheter; however, before it is inserted into the guide catheter, no negative pressure is created. The stent-balloon catheter is then advanced over the guide wire through the guide catheter beyond distal opening and across the lesion. The stent is positioned over the lesion by confirming its placement with the injection of a small amount of contrast material through the guide. The guide catheter is pulled back on the wire a little to allow the proximal edge of the stent to be slightly in the aorta. Before the stent balloon is inflated, the guide catheter is pushed upward to straighten the stent and wire in the proximal portion of the renal artery. The stent is then deployed by first creating negative pressure in the stent balloon and then by inflating it by injecting the contrast agent–saline solution through the inflation device. The stent is left inflated for several seconds at 5-10 bars of pressure. The balloon is then deflated and withdrawn while the guide wire is retained across the lesion, and the guide catheter is slightly advanced into the stent.

The stent is then deployed by first creating negative pressure in the stent balloon and then by inflating it by injecting the contrast agent–saline solution through the inflation device. The stent is left inflated for several seconds at 5-10 bars of pressure. The balloon is then deflated and withdrawn while the guide wire is retained across the lesion, and the guide catheter is slightly advanced into the stent. (See the image below.)

Fluoroscopic image shows the guide wire still lyin Fluoroscopic image shows the guide wire still lying across the stented segment. The stent shadow is visible in the proximal portion of the right renal artery, and it appears well expanded.

Next, after the absence of a flap, dissection, or filling defect is confirmed, the guide wire is withdrawn. Poststenting angiography is performed to look for any residual stenosis in the proximal renal artery. Finally, the guide catheter is withdrawn.

Last, the guidewire is withdrawn after the absence Last, the guidewire is withdrawn after the absence of a flap, dissection, or filling defect is confirmed. Poststenting angiogram shows 0% residual stenosis in the proximal renal artery. The guide catheter is finally withdrawn.
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Complications

The rate of restenosis in patients with atheromatous disease has been reported to be 19% after 9 months and 35% if the lesion is ostial. The latter rate may be an underestimate.

In the randomized study by Weibull, [28] the 1-year rate of restenosis was 25%. Losinno et al reported a 5-year patency rate of 82%, though this percentage was based on an incomplete sample of patients.

Other complications of angioplasty include the following:

  • Hematoma at the puncture site
  • Azotemia, caused by the dye load
  • Cholesterol emboli

These complications tend to be more common in old patients with diffuse atheromatous disease than in others.

When PTA is performed in patients with elevated creatinine levels, alternative contrast agents such as carbon dioxide and gadolinium-based contrast agents (eg, gadopentetate dimeglumine, gadobenate dimeglumine, gadodiamide, gadoversetamide, and gadoteridol) may be used to minimize the risk of azotemia as a complication of renal angioplasty. Findings from early clinical experience suggest that distal protection devices used during stenting of carotid arteries may effectively filter debris produced during renal angioplasty and stenting, preventing renal failure.

However, gadolinium-based contrast agents have been linked to the development of nephrogenic systemic fibrosis (NSF) or nephrogenic fibrosing dermopathy (NFD). For more information, see Nephrogenic Systemic Fibrosis. NSF/NFD is a debilitating and sometimes fatal disease. Characteristics include the following:

  • Red or dark patches on the skin
  • Burning, itching, swelling, hardening, and tightening of the skin
  • Yellow spots on the whites of the eyes
  • Joint stiffness with trouble moving or straightening the arms, hands, legs, or feet
  • Pain deep in the hip bones or ribs
  • Muscle weakness

The disease has occurred in patients with moderate to end-stage renal disease after a gadolinium-based contrast agent was given to enhance magnetic resonance imaging (MRI) or magnetic resonance angiography (MRA) scans. For more information, see the FDA Drug Warning or this article.

Dissection or occlusion of the renal artery may also occur, but this is rare. When this complication occurs, renal stenting may restore renal blood flow. Acute pulmonary edema as a complication of angioplasty has been reported in a patient with bilateral RAS.

In one large series, the 30-day mortality was 2.2%; all deaths occurred in patients with atheroma.

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