Percutaneous transluminal angioplasty (PTA) and stenting in bilateral renal artery stenosis - Vascular surgery

Puncture the left femoral artery at the groin in Seldinger technique and carefully introduce the guidewire. After removing the puncture cannula, introduce a 6F sheath over the indwelling guidewire under fluoroscopic guidance. After removing the wire, administer 5000 IU of heparin saline solution locally and check for pulsatile reflux.

Tips:

1. A severely calcified artery may be difficult to puncture. Care must be taken when puncturing the artery and introducing the guide wire not to dissect the vessel.

2. If percutaneous puncture in both groins fails, make a mini-incision in one groin, expose the common femoral artery there and then puncture under direct vision.

Advance a Terumo® guidewire through the sheath and introduce a pigtail catheter into the suprarenal aorta. Perform survey angiography of the aorta and renal artery in road-mapping technique. Angiography reveals bilateral subtotal stenosis of the renal arteries close to their origins. Next, in this mask place a Renal Double Curve (RDC) catheter into the suprarenal aorta. Slowly retract the guidewire until it slips into the infundibulum at the origin of the left renal artery. Once the guidewire is seated securely, exchange the Terumo® guidewire for a soft-tipped thinner, but harder, metal wire, advancing it carefully into the peripheral renal artery.

Tips:

1. Do not advance the metal wire too far. The resistance must be felt, otherwise the kidney will be perforated, resulting in severe parenchymal hemorrhage. 

2. Why does the Terumo® catheter have to be replaced with a harder metal catheter in the first place? This is necessary to obtain sufficient thrust for the balloon-expandable stent to be released in the next surgical step. A soft Terumo® guidewire would dislodge and the stent could not be delivered accurately because it would lack central purchase. 

Roadmapping („Pathfinder“):

This involves the administration a small bolus of contrast agent to visualize the abdominal aorta as a roadmap. This image is saved as a mask. Subsequent images are then acquired without contrast media and subtracted from the mask. In this way, for example, only the current position of a radiopaque catheter will be displayed. In the resulting subtraction images, the bright catheter will be visible against the dark background of the abdominal aorta, and any background irrelevant to this study is omitted.

Because of the presumed ulcerated lumen of the stenosed renal arteries, avoid dissection and embolization from the outset by not predilating and deliver a 5 mm stent (length 20 mm).

Advance the balloon-expandable stent through the RDC catheter and over the guidewire into the renal artery in roadmapping technique, and then carefully withdraw the RDC catheter. Deliver the stent with its central end approximately 1 mm outside the renal artery ostium in the aorta. Secure the guidewire and RDC catheter firmly to the patient's thigh to prevent dislodgement. Then deploy the stent by inflating the balloon. 

Caution:

Do not inadvertently deploy the stent in the RDC catheter. This would create significant technical problems. In case of partial stent protrusion, there would even be the risk of dissection or perforation when retracting the guidewire.

Note:

True renal artery stenosis at its aortic ostium is always caused by the calcified aortic wall. After balloon dilation, these stenoses always constrict like the iris diaphragm in a camera. Such stenoses always require stenting. Sometimes such stenoses are so hard that they must be predilated before stenting can be performed. Otherwise, the stent could not pass through the stenosis and might become damaged.

In most cases, stenosis directly downstream of the renal artery orifice is also very hard and the aorta likewise exhibits severe arteriosclerotic changes, as in the present case. Similarly, these stenoses quite often require stenting because the short-term postoperative outcome is poor.

RAS far from its ostium is mostly eccentric and easily dilated. This type of stenosis requires stenting only if there is significant residual stenosis following dilation.

Fibromuscular dysplasia of the renal arteries usually requires stenting because of their tendency to undergo restenosis due to the connective-tissue like scarring of the arterial wall with intimal ridges.

Verification angiography demonstrates complete restitution of the renal artery lumen and proper stent placement.