Endovascular Therapeutic Techniques

1.      Balloon Angioplasty: Transluminal dilation of stenotic atherosclerotic arterial lesion-may be done during surgery or Percutanaeous (PTA).

First describe by Dotter in 1964-now non elastomeric balloons are used i.e. can withstand high inflation pressure without distortion of shape or over stretching.

        Indications:

Ø      Localised, short Stenotic Lesions or short occlusion.e.g. Iliac, femoral.

Ø      Renovascular stenosis

       Technique:

Ø      Femoral arteriogram is performed

Ø      Guide wire is inserted through the stenosis

Ø      The balloon catheter is inserted over the guide wire

Ø      The balloon is positioned within the stenosis.

Ø      The balloon is inflated for one minute and then deflated

Ø      Repeat inflation and deflation

Ø      Withdraw catheter

Best results are obtained in short stenotic lesions of common iliac artery 50-70% patency rate at 4 years interval has been reported.

The results of PTA of infra-inguinal arterial disease are not as good as for aortoiliac disease.

Ø      Intermittent claudication as the presenting symptom  rather than limb salvage

Ø      Short stenosis

Ø      Good  run off of the distal vessels

The only suitable approach for Femoropopliteal or tibial Angioplasty in severe limb ischemia is to use the technique in a limited and highly selective group of isolated short lesions.

2.      Laser Angioplasty: limited indication and low success rate

Ø      Short arterial stenosis or occlusion

Ø      Iliac artery disease

Ø      PTFE graft occlusion secondary to intimal hyperplasia

Ø      Contr indication of surgery

      Laser provides high energy ablation of tissue => recnalization.

      Complication:

Ø      Vessel wall disection

Ø      Perforation

Results of laser recanalization are still disappointing.

3.      Atherectomy:  Atherectomy catheter can be used percutaneously or used as part of sugery. I.e. during surgical bypass.

Mechanism: Atherectomy devices remove the plaques from the vessels by cutting or drilling atheroma.

Indications:

Ø      Extraction of fragments percutaneously

Ø      Reduce plaque into micro particles

Ø      May be used as a sole therapy or in conjugation with balloon dilatation

Ø      If a stenotic arterial lumen is not sufficiently enlarged after atherectomy procedure , balloon  dilatation is performed

Ø      Dissections or acute occlusion after balloon Angioplasty may be improved by subsequent  passage of an atherectomy catheter

      Complications:

Ø      Fragmentation

Ø      Embolization

Ø      Thrombosis

4.      Intravascular stents (intraluminal splints): in certain circumstances after balloon dilatation, the vessel fails to stay adequately dilated, it then may be possible to hold the lumen open by using a stent.

Types:

Ø              Stainless steel spring loaded stents

Ø              Thermally expanded memory metal stent

Ø              Balloon expandable stent

      

 Stents are most beneficial in large diameter high flow vessel e.g. iliac artery stenosis, SVC stenosis, and Aortoiliac stenosis.

The usefulness of stents may be to treat acute reclosure of angioplasties from residual thrombotic material, flaps or dissection or from recoil of the vessel wall

Complications:

Ø   Dislodgement

Ø   Migration

Ø    Embolization

5.    Other endovascular Angioplasty devices:

Ø      Non Laser thermal Angioplasty

Ø      Ultrasonic  ablation device

Ø      Electrical ablation device

Ø      Thermal  ablation device

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