18.3 TAVI/TAVR

TAVI/TAVR

ARRT Cardiac-Interventional Procedures 2.B.3 is transcatheter aortic valve implantation (TAVI) / transcatheter aortic valve replacement (TAVR) — same procedure, two names. The Focus of Questions still applies: anatomy and pathophysiology, indications, contraindications, imaging, access, ultrasound, equipment, complications, and closure. This is large-bore structural work in a hybrid OR with surgical backup.

Quick Answer: Severe symptomatic aortic stenosis (AS) is the core indication; selected aortic regurgitation (AR) and valve-in-valve for a failed surgical bioprosthesis are also in play. Transfemoral access is first-line; then transaxillary, transcarotid, transapical, transcaval. CT sizes the annulus, coronary height, and iliofemoral vessels. Balloon-expandable valves need rapid RV pacing at deployment; self-expanding valves unsheath and recapture on some platforms. Watch annular rupture, coronary obstruction, paravalvular leak (PVL), stroke, new LBBB/CHB needing a pacemaker, and vascular injury. Image with TEE or ICE plus a fluoro coplanar view.

Anatomy, pathophysiology, indications, contraindications

Calcific AS (senile/degenerative) is the usual adult substrate: a restricted trileaflet or bicuspid valve, high transvalvular gradient, and LV pressure overload. Rheumatic and congenital bicuspid disease appear in younger patients. Severe symptomatic AS (syncope, angina, heart failure) is the historic reason to replace the valve; untreated severe symptomatic AS has poor survival.

Indications (teaching): severe symptomatic AS in patients across the current surgical-risk spectrum when anatomy is suitable — originally prohibitive/high surgical risk, later intermediate and selected low risk as evidence matured. Do not invent unpublished ARRT STS-score cutoffs. Additional teaching indications: valve-in-valve TAVR inside a failed surgical bioprosthesis, and selected pure or predominant AR on platforms and anatomies that can anchor without relying only on stenosis calcium. AR is not the classic first TAVR story.

Contraindications / stops: annulus too large or too small for available valves, coronaries too low with bulky leaflets and no protection plan, inadequate iliofemoral access with no alternative access, active endocarditis, LV thrombus, and a team that cannot convert to surgery. Life expectancy too short to benefit is a heart-team decision, not a technologist veto.

Access routes

Transfemoral arterial is first-line when CT shows adequate iliofemoral diameter, limited circumferential calcium, and acceptable tortuosity. Fully percutaneous with suture-mediated preclose. Lowest morbidity among access choices when anatomy cooperates. Do not invent unpublished ARRT millimeter cutoffs — the CT report plus the chosen sheath’s labeled profile decide “adequate.”

If femoral vessels fail:

• Transaxillary / subclavian — usually left axillary; watch the IMA if it is a graft.
• Transcarotid — surgical exposure of a carotid; neuro monitoring.
• Transapical — left mini-thoracotomy through the LV apex; more invasive, still used when no extra-thoracic arterial path exists.
• Transcaval — femoral vein to IVC, then a crossing into the abdominal aorta, large-bore up to the valve, then close the aorto-caval fistula with an occluder. Rescue access, not first-line.
• Transaortic (mini-sternotomy to ascending aorta) appears in some programs.

Imaging, ultrasound, CT sizing, coplanar view

Pre-procedure CT is the anatomic gold standard: annulus area and perimeter, calcium, coronary ostial height (low height plus a bulky leaflet is coronary obstruction), sinus width, membranous septum length (conduction risk), bicuspid morphology, and iliofemoral luminal diameter, calcium, and tortuosity. Echo (TTE/TEE) grades AS/AR and LV function. Cath still documents coronaries and, if needed, a confirmation gradient.

Intraprocedural imaging. Fluoroscopy in a coplanar view of the annulus (all three cusps aligned in one plane — typically a combination of caudal/cranial and RAO/LAO derived from CT) is how the valve is landed at the right depth. TEE (general anesthesia) or ICE (often conscious-sedation transfemoral programs) watches position, leaflets, PVL, and effusion. A root aortogram after deploy looks for PVL and coronary filling. Vascular ultrasound guides the large-bore femoral sticks and assesses the vessels after closure.

Equipment: balloon-expandable versus self-expanding, pacing

Balloon-expandable valves (Sapien-class teaching) are crimped on a balloon and expanded in one inflation. Rapid right-ventricular pacing (temporary RV wire or LV pacing via the wire; teaching rates often ~160–200/min — lab teaching, not an unpublished ARRT cutoff) drops stroke volume so the balloon/valve does not eject during the inflation. Oversize plus a heavily calcified annulus is the annular rupture setup.

Self-expanding valves (Evolut/CoreValve-class teaching) are nitinol, constrained in a sheath, and unsheathed. Many generations can be recaptured/repositioned before final release. Rapid pacing is less central to frame expansion (some labs still pace for aortography or for a balloon predilatation). Self-expanding frames sit deeper into the LVOT on many implants — historically more new conduction disturbance (LBBB, high-grade AV block) and permanent pacemaker. They are often preferred when annular rupture risk is high or for some valve-in-valve and AR anatomies because of oversizing behavior.

Predilatation (balloon aortic valvuloplasty) is used when the native valve will not let the device cross; postdilatation treats PVL from underexpansion — and raises rupture and conduction risk. A cerebral embolic protection device (filter in the innominate and left carotid) appears in some labs; treat it as adjunctive stroke-risk equipment, not as proof that stroke cannot happen.

Temporary RV pacing must work before balloon-expandable deployment. Loss of capture at the moment of inflation is how the valve jumps. Do not pull the RV wire the minute the frame looks pretty if a new LBBB is on the monitor.

Complications and closure

Annular rupture: sudden tamponade or mediastinal bleed during or after balloon-expandable implant or aggressive postdilatation. Hybrid OR / CPB / surgery now.

Coronary obstruction: a native or surgical leaflet is pushed over a low coronary ostium. Acute ischemia, shock. Protection (wire in the coronary, chimney stent) is planned from CT coronary height, not improvised after the aortogram is black. Valve-in-valve cases can raise this risk when surgical leaflets are displaced outward.

Paravalvular leak (PVL): contrast around the frame. Mild PVL may be watched; significant PVL is postdilatation, a second valve, or a plug — PVL is associated with worse outcomes, not a free LV-unloading gift.

Stroke: aortic arch and valve calcium embolize. Minimize unnecessary catheter manipulation; protection devices if used; neuro checks.

Conduction: the frame compresses the left bundle / His at the membranous septum. New LBBB and complete heart block may need temporary pacing and often a permanent pacemaker. Self-expanding implants carry the heavier historical pacemaker lecture; balloon-expandable implants are not immune.

Vascular injury: large-bore femoral dissection, occlusion, or retroperitoneal bleed. Iliac rupture is a covered-stent / surgical emergency.

Closure. Preclose sutures (often two suture-mediated devices) before upsizing the TAVR sheath, then cinch after the sheath comes out; surgical cutdown if percutaneous closure fails. Alternative-access sites have their own surgical closures (carotid, apex, axillary). Document distal pulses. Venous pacing-wire hemostasis is separate. Need for a hybrid OR and surgical backup is not optional window dressing: rupture, obstruction, and iliac catastrophe are minutes, not a hallway transfer (14.1).

Table: access / valve type / unique complication

Worked case

CT: severe AS, annulus suitable, coronary heights adequate, right iliac heavily calcified and too small for the planned sheath. Do not force transfemoral. Plan transaxillary or transcarotid in a hybrid OR. If femorals had been adequate and the operator chose a balloon-expandable valve, confirm RV pacing capture, a coplanar cusp view, and TEE/ICE before the inflation. After deploy, aortography shows a dark coronary and ST elevation: coronary obstruction — not “the pacing wore off.” If instead the problem is a new wide LBBB and a long pause, leave the temporary pacemaker and plan for PPM risk, especially after a self-expanding implant. A sudden pericardial effusion after postdilatation of a balloon-expandable valve in a calcium-heavy annulus is annular rupture until surgery says it is not.

Exam traps

• Forcing transfemoral on inadequate CT iliofemoral anatomy.
• Deploying a balloon-expandable valve without rapid RV pacing.
• Ignoring coronary height on CT.
• Pulling the temporary pacemaker immediately after a new LBBB.
• Calling TAVR a table-suite case with no surgical backup.
• Treating PVL as irrelevant because the transvalvular gradient fell.