Renal Artery Angioplasty and Stenting
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 middle-aged woman with malignant renovascular hypertension. Preprocedural right renal arteriogram was obtained after sterile preparation and draping of patient, conscious sedation, infiltration of local anesthetic (lidocaine 1% or 2% solution) at femoral access site, placement of arterial sheath in femoral artery, and advancement of renal guide catheter over 0.035-in. guide wire under fluoroscopic guidance. After tip of guide catheter is positioned at ostium of renal artery, angiogram (as shown here) is obtained. After guide wire is removed, proximal end of catheter is connected to manifold, and 4-8 mL of contrast is manually injected during cineangiographic recording. Once obtained, image may be played over and over in loop, or particular frame may be saved for review during angioplasty. Intravenous antithrombotic agent, usually heparin, is administered before clinician proceeds with angioplasty. Patient's activated clotting time is monitored.
Preangioplasty angiogram obtained in young woman with malignant hypertension shows tight stenosis in middle segment of right renal artery. Its appearance is consistent with that of fibromuscular dysplasia (FMD), for which angioplasty is procedure of choice and for which stenting is usually not indicated. Intra-arterial nitroglycerin, 300 mcg, was given without any change in appearance of stenosis (which differentiates it from spasm). In general, intra-arterial nitroglycerin injection is not necessary to differentiate it from FMD that has been demonstrated on prior abdominal aortogram.
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 with 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.)
Guide wire (0.018-in.) is advanced through 6F renal guide across ostial right renal stenosis. Small torque device is used over proximal segment of guide wire for steering, while small terminal bend is created by hand over distal end of guide wire before it is introduced into guide catheter. Passage of guide wire is monitored by using fluoroscopy and injections of small amounts of contrast agent. Occasionally, combination of torque and forward pressure is required to cross lesion. In addition, in tight lesions, balloon catheter is sometimes advanced and used as support for passage of 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.)
Balloon (6 mm × 18 mm) is positioned across lesion by carefully advancing it over guide wire. Balloon is prepared before it is loaded over guide wire by connecting its proximal balloon port to inflating device that contains half-and-half solution of contrast agent and sterile saline and then by drawing negative pressure to extrude any air bubbles. Inflating device is left in negative pressure while balloon is advanced with one hand and guide wire is held with the other. Balloon is advanced beyond distal end of guide catheter, which is gently pulled back, and balloon is straddled across stenosed segment. Small amount of contrast agent is injected to confirm proper positioning of balloon.
The balloon is inflated by increasing the pressure with the inflation device to several atmospheres of pressure (usually 4-8 bars, or 400-800 kPa). 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.
Balloon is inflated by increasing pressure with inflation device to several atmospheres of pressure (usually 4-8 bars, or 400-800 kPa). Mixed solution of contrast agent and saline in inflation device gradually moves into balloon. As balloon expands, it becomes visible under fluoroscopy, as shown. Balloon is held up for several seconds to apply circumferential pressure on stenosed arterial segment, then deflated and gradually pulled back into guide catheter.
Fluoroscopic image shows inflated percutaneous transluminal angioplasty (PTA) balloon in midright renal artery over guide wire. In this case, Judkins right 4 (JR4) guide was used to access right renal artery via right femoral approach. Balloon was left inflated for several seconds, then deflated and pulled out. Additional intra-arterial nitroglycerin 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 angioplasty and after balloon catheter is removed, but while guide wire is still retained, shows increased luminal diameter at stenotic segment. However, segment appears to be at least 50% narrowed. Flow into renal artery from aorta is increased. Vascular wall shows no clear dissection. No filling defect (which may represent clot) is visible. Distal flow into branches of right renal artery is brisk, with good nephrogram.
Angiogram obtained after percutaneous transluminal angioplasty and after balloon catheter was removed shows good result with residual stenosis of < 20% at previously stenosed site. Flow into renal artery from aorta is increased. Vascular wall shows no clear dissection. No filling defect (which may represent clot) is visible. Distal flow into branches of right renal artery is brisk, with good nephrogram.
Preparation of a stent-balloon catheter is similar to that of a balloon catheter; however, no negative pressure is created for 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.)
Stent-balloon catheter is prepared in manner similar to balloon catheter; however, before it is inserted into guide catheter, no negative pressure is created. Stent-balloon catheter is then advanced over guide wire through guide catheter beyond distal opening and across lesion. Stent is positioned over lesion by confirming its placement with injection of small amount of contrast material through guide. Guide catheter is pulled back on wire slightly to allow proximal edge of stent to be slightly in aorta. Before stent balloon is inflated, guide catheter is pushed upward to straighten stent and wire in proximal portion of renal artery. Stent is then deployed by first creating negative pressure in stent balloon and then inflating it by injecting contrast agent–saline solution through inflation device. Stent is left inflated for several seconds at 5-10 bars (500-1000 kPa) of pressure. Balloon is then deflated and withdrawn while guide wire is retained across lesion, and guide catheter is slightly advanced into stent.
Next, the stent is deployed by first creating negative pressure in the stent balloon and then 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 (500-1000 kPa) 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 guide wire still lying across stented segment. Stent shadow is visible in proximal portion of 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, guide wire is withdrawn after absence of flap, dissection, or filling defect is confirmed. Poststenting angiogram shows 0% residual stenosis in proximal renal artery. Guide catheter is finally withdrawn.
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, [32] 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. [51]
Other complications of angioplasty include the following:
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Hematoma at the puncture site
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Azotemia, caused by the dye load
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Cholesterol emboli
These complications tend to be more common in old patients with diffuse atheromatous disease than in others.
When PTRA 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 suggested 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). NSF/NFD is a debilitating and sometimes fatal disease. Characteristics include the following:
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Red or dark patches on the skin
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Burning, itching, swelling, hardening, and tightening of the skin
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Yellow spots on the whites of the eyes
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Joint stiffness with trouble moving or straightening the arms, hands, legs, or feet
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Pain deep in the hip bones or ribs
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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. Renal subcapsular hematoma due to reperfusion injury has been reported after PTRA. [52]
In one large series, the 30-day mortality was 2.2%; all deaths occurred in patients with atheroma.
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Renal artery stenosis in patient with medically refractory renovascular hypertension.
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Percutaneous transluminal angioplasty.
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Renal arteriogram obtained after renal percutaneous transluminal angioplasty.
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Percutaneous transluminal renal angioplasty in middle-aged woman with malignant renovascular hypertension. Preprocedural right renal arteriogram was obtained after sterile preparation and draping of patient, conscious sedation, infiltration of local anesthetic (lidocaine 1% or 2% solution) at femoral access site, placement of arterial sheath in femoral artery, and advancement of renal guide catheter over 0.035-in. guide wire under fluoroscopic guidance. After tip of guide catheter is positioned at ostium of renal artery, angiogram (as shown here) is obtained. After guide wire is removed, proximal end of catheter is connected to manifold, and 4-8 mL of contrast is manually injected during cineangiographic recording. Once obtained, image may be played over and over in loop, or particular frame may be saved for review during angioplasty. Intravenous antithrombotic agent, usually heparin, is administered before clinician proceeds with angioplasty. Patient's activated clotting time is monitored.
-
Guide wire (0.018-in.) is advanced through 6F renal guide across ostial right renal stenosis. Small torque device is used over proximal segment of guide wire for steering, while small terminal bend is created by hand over distal end of guide wire before it is introduced into guide catheter. Passage of guide wire is monitored by using fluoroscopy and injections of small amounts of contrast agent. Occasionally, combination of torque and forward pressure is required to cross lesion. In addition, in tight lesions, balloon catheter is sometimes advanced and used as support for passage of guide wire.
-
Balloon (6 mm × 18 mm) is positioned across lesion by carefully advancing it over guide wire. Balloon is prepared before it is loaded over guide wire by connecting its proximal balloon port to inflating device that contains half-and-half solution of contrast agent and sterile saline and then by drawing negative pressure to extrude any air bubbles. Inflating device is left in negative pressure while balloon is advanced with one hand and guide wire is held with the other. Balloon is advanced beyond distal end of guide catheter, which is gently pulled back, and balloon is straddled across stenosed segment. Small amount of contrast agent is injected to confirm proper positioning of balloon.
-
Balloon is inflated by increasing pressure with inflation device to several atmospheres of pressure (usually 4-8 bars, or 400-800 kPa). Mixed solution of contrast agent and saline in inflation device gradually moves into balloon. As balloon expands, it becomes visible under fluoroscopy, as shown. Balloon is held up for several seconds to apply circumferential pressure on stenosed arterial segment, then deflated and gradually pulled back into guide catheter.
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Angiogram obtained after percutaneous transluminal angioplasty and after balloon catheter is removed, but while guide wire is still retained, shows increased luminal diameter at stenotic segment. However, segment appears to be at least 50% narrowed. Flow into renal artery from aorta is increased. Vascular wall shows no clear dissection. No filling defect (which may represent clot) is visible. Distal flow into branches of right renal artery is brisk, with good nephrogram.
-
Stent-balloon catheter is prepared in manner similar to balloon catheter; however, before it is inserted into guide catheter, no negative pressure is created. Stent-balloon catheter is then advanced over guide wire through guide catheter beyond distal opening and across lesion. Stent is positioned over lesion by confirming its placement with injection of small amount of contrast material through guide. Guide catheter is pulled back on wire slightly to allow proximal edge of stent to be slightly in aorta. Before stent balloon is inflated, guide catheter is pushed upward to straighten stent and wire in proximal portion of renal artery. Stent is then deployed by first creating negative pressure in stent balloon and then inflating it by injecting contrast agent–saline solution through inflation device. Stent is left inflated for several seconds at 5-10 bars (500-1000 kPa) of pressure. Balloon is then deflated and withdrawn while guide wire is retained across lesion, and guide catheter is slightly advanced into stent.
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Fluoroscopic image shows guide wire still lying across stented segment. Stent shadow is visible in proximal portion of right renal artery, and it appears well expanded.
-
Last, guide wire is withdrawn after absence of flap, dissection, or filling defect is confirmed. Poststenting angiogram shows 0% residual stenosis in proximal renal artery. Guide catheter is finally withdrawn.
-
Preangioplasty angiogram obtained in young woman with malignant hypertension shows tight stenosis in middle segment of right renal artery. Its appearance is consistent with that of fibromuscular dysplasia (FMD), for which angioplasty is procedure of choice and for which stenting is usually not indicated. Intra-arterial nitroglycerin, 300 mcg, was given without any change in appearance of stenosis (which differentiates it from spasm). In general, intra-arterial nitroglycerin injection is not necessary to differentiate it from FMD that has been demonstrated on prior abdominal aortogram.
-
Fluoroscopic image shows inflated percutaneous transluminal angioplasty (PTA) balloon in midright renal artery over guide wire. In this case, Judkins right 4 (JR4) guide was used to access right renal artery via right femoral approach. Balloon was left inflated for several seconds, then deflated and pulled out. Additional intra-arterial nitroglycerin was infused.
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Angiogram obtained after percutaneous transluminal angioplasty and after balloon catheter was removed shows good result with residual stenosis of < 20% at previously stenosed site. Flow into renal artery from aorta is increased. Vascular wall shows no clear dissection. No filling defect (which may represent clot) is visible. Distal flow into branches of right renal artery is brisk, with good nephrogram.
Tables
- Table 1. Success Rates of Percutaneous Transluminal Renal Angioplasty (PTRA) in Renal Artery Stenosis (RAS) Caused by Atherosclerosis (80% of RAS) and Fibromuscular Dysplasia (FMD; 20% of RAS) [27, 28]
- Table 2. Success Rates of Percutaneous Transluminal Renal Angioplasty (PTRA) in Renal Artery Stenosis (RAS) Caused by Atherosclerosis (80% of RAS) [23, 31, 32]
- Table 3. Natural History: Progression of Medically Treated Renal Artery Stenosis [34]
- Table 4. Effect of Renal Stenting on Serum Creatinine Level [28]
Outcome |
Atherosclerotic RAS, % |
RAS Due to FMD, % |
Primary success |
85 |
89 |
Hypertension cured |
19 |
41 |
Hypertension improved |
61 |
44 |
Restenosis |
50 |
15 |
Intervention |
Success Rate, % |
Restenosis Rate, % |
PTRA |
85 |
50 |
Renal stenting |
100 |
25 |
Outcome |
Rate, % |
Decrease in glomerular filtration rate |
37 |
Increase in creatinine level |
20 |
Decrease in renal size |
35 |
Change in Creatinine Level |
Rate, % |
Improved |
29 |
None |
67 |
Worsened |
4 |
