Stents and Meshes

Lecture #10

Angioplasty

Opening up plaque-narrowed artery without doing major surgeryCatheter w/balloon tip inserted into coronary or major leg or arm arteryInflation of balloon

often repeatedlystretches artery walldisrupts plaques

Stents

wire meshUsed in 70-90% of all angioplasty procedureskeeps the vessel open after wideningTwo types

placed onto balloon prior to insertion (balloon expandable stent)Placed on a delivery system (self-expanding stent)

permanently attached as balloon inflates

Stent Types

Self-expanding: woven NiTi

Balloon expandable: stainless

Self-expanding: PTFE-coated NiTi

Uses of the Procedure

Open narrowed or blocked coronary artery in patients suffering from angina –alternative to bypass surgeryOpen a blocked artery in the pelvis, leg, or arm –peripheral arterial diseaseControl blood pressure in renal hypertension –caused by narrowing of one or both arteries supplying kidneys

To keep blood vessel grafts open in patients undergoing hemodialysis – most have a graft between a artery and vein in the arm to easily draw and replace bloodMaintain blood flow to the brain by keeping open the carotid artery

Ref: www.radiologyinfo.org/content/interventional/angioplasty.com

Advantages of Angioplasty

Less invasiveMajor surgery avoidedLower costShort hospital stayLocal anesthesiaNo incisionRelieve symptoms – though perhaps not as long

Risks

Angioplasty alone20-33% chance of recurrence of blockage in a few days or weeksReduced with the use of a stent

Risk of coronary angioplasty same as surgery1-3% die during or shortly after procedure3-5% experience a heart attack<3% require bypass surgery because of damage to the arterial wall during procedure

Alergic reaction to contrast materialHeavy bleeding at insertion siteDisruption of normal rhythm of the heartRisk of stroke when angioplasty/stenting performed on carotid artery

Endografts

Used to repair Abdominal Aortic Aneurism (AAA)Closely resembles an arterial graftGraft with metallic stentsInserted through both femoral arteriesDiverts blood flow away from aneurismDoes not remove aneurism – aneurism shrinks around graft

Surgical Meshes – Hernia Repair

Hernia – occurs when a piece of intestine slips through a weakness in the abdominal wallDiagnosed as early as 1564

Truss – mechanical device used to push the hernia back in

Two modern treatmentsTension RepairTension-free repair

Tension Repair

Incision made over site of herniaProtruding tissue pushed back inWound sutured shutToday

ChildrenSmall hernias

DisadvantagesDiscomfort4-6 week recovery10-15% recurrence

Meshes

Woven, knitted or non-wovenNatural (collagen) or synthetic (PPE, PET, PTFE)

Tension-Free – Flat Mesh

After making incision polypropylene mesh stitched to tissueAdvantages

Only 3% recurrenceQuick recoveryMinor discomfortLocal anesthesia

DisadvantagesMany stitches for large hernia – nerve damage40-60 minutes

Tension Free – Plug and Patch

Similar to flat mesh –but 2 fabricsDisadvantages

Does not protect well against new herniasPlug may shrink

RecurrencePosition change

Some can feel plug through skin

Tension Free - Laparoscopic

Mesh placed inside abdominal wall using laparascopeAdvantages

Pressure within abdomen holds mesh in place – no stitches

DisadvantagesGeneral anesthesiaCan require overnight stayTakes up to 60 min.

Tension Free – Kugel Patch

Mesh with firm outer ring Advantages

Minimally invasiveLocal anesthesiaFewer stitches

DisadvantagesFirm outer rim may cause discomfort after surgeryRecurrence due to patch movement

Tension Free – 3D Patch Repair

PROLINE Hernia System (Ethicon)3 components

Underlay patch for interior of abdominal wallConnector/plug“Onlay” patch on top of abdominal wall

AdvantagesComfortLow possibility of migrationMinimal suturingLocal anesthesia20 minutesQuicker recovery

DisadvantagesNew –no surgeon training