19.3 Left Atrial Appendage Closure

Left Atrial Appendage Closure

ARRT Cardiac-Interventional Procedures 2.B.6 is left atrial appendage (LAA) closure. The devices the R.T.(CI) will actually open are Watchman-class (single-lobe plug) and Amulet-class (lobe-and-disk) occluders. This is not a PFO double-disk (18.1), not a mitral clip (19.2), and not BAV. The Focus of Questions still applies: anatomy and pathophysiology, indications, contraindications, imaging, access, ultrasound, equipment, complications, and closure.

Quick Answer: LAA closure is for AF patients who need an alternative to long-term anticoagulation. TEE or CT sizes the appendage and excludes thrombus. Access is femoral venous then transseptal, guided by ICE or TEE. Land in the LAA ostium / landing zone, confirm with a tug test, and look for peri-device leak. A classic Watchman sequence of warfarin plus aspirin, then DAPT, then aspirin is an example protocol, not an ARRT mandate. Disasters: pericardial effusion/tamponade, device embolization, stroke, vascular injury.

Anatomy, pathophysiology, indication, contraindication

The LAA is a trabeculated outpouching of the LA — windsock, chicken-wing, cauliflower, or cactus in CT/TEE slang. In nonvalvular atrial fibrillation, the appendage is the dominant site of LA thrombus that later embolizes as ischemic stroke. Oral anticoagulation (warfarin or a DOAC) is first-line stroke prevention when the stroke-risk score warrants it. Percutaneous LAA closure is for the patient who needs an alternative to long-term anticoagulation: prior major bleeding, high bleeding risk, labile INR with inability to use a DOAC, or another documented reason the heart team will not commit to lifelong OAC. It is not a toy for every AF ablation, and it is not indicated to stop anticoagulation in a patient who is doing fine on a DOAC with no bleeding story.

Contraindications / stops: thrombus already in the LAA (do not implant on clot), an appendage too small or too shallow for available devices, anatomy no device will seal (some chicken-wing necks), active endocarditis or bacteremia, a contraindication to the planned post-implant antithrombotic window (even a short one), and no echo/CT roadmap. Valvular AF with a mechanical mitral prosthesis is a different anticoagulation problem — an LAA plug does not cancel a mechanical-valve warfarin indication.

Imaging, sizing, thrombus exclusion, ultrasound

Pre-procedure TEE or CT is how you size. TEE teaching sweeps 0°, 45°, 90°, and 135° to measure ostial width and depth; CT gives 3D ostium, landing-zone diameter, and the relationship to the pulmonary veins and circumflex. Do not invent unpublished ARRT millimeter cutoffs — match the measured landing zone to the labeled device chart. Exclude thrombus on the same TEE or on a recent CT/TEE. Smoke (spontaneous echo contrast) is not the same as a formed thrombus, but a definite LAA thrombus is a stop: anticoagulate and restudy.

Intraprocedural imaging. TEE or ICE (or both) guides transseptal puncture, sheath depth in the LAA, device unfolding, compression, peri-device color leak, and a new pericardial effusion. Fluoroscopy in RAO/caudal teaching views shows the LAA outline after a gentle contrast injection; fluoro does not replace echo thrombus exclusion. Vascular ultrasound guides the femoral venous stick.

Access, equipment, landing, tug test

Access. Femoral venous (usually right) → RA → transseptal puncture into the LA → steer a dedicated delivery sheath into the LAA. Puncture location is typically more inferior and posterior than a mitral-clip puncture so the sheath points at the appendage rather than the mitral valve. This is not arterial Watchman, and it is not “cross a PFO instead of puncturing.” Heparin after the LA is entered; ACT is lab protocol.

Watchman-class devices are a self-expanding nitinol frame with a fabric cover that sits in the landing zone at the LAA ostium, covering the mouth. After deployment, operators confirm position, compression of the frame (enough to hold, not so much the LAA tears), and a tug test: gentle traction on the delivery cable to prove the device is stable before release. Amulet-class devices use a lobe in the landing zone plus a disk that covers the ostium (dual-seal teaching). Know plug versus lobe-and-disk; do not mix them up with an ASD occluder.

Peri-device leak is color Doppler around the fabric at the ostium. A significant leak is residual communication with the trabeculated LAA — residual embolic risk, and a reason not to stop the planned antithrombotic path. Historic Watchman teaching tolerated small leaks below a lab threshold (often discussed around 5 mm — lab teaching, not an unpublished ARRT cutoff). Newer teaching prefers no leak. Either way, document the leak; do not call a wide color jet a sealed appendage.

Antithrombotic example protocol — not an ARRT mandate

Endothelialization takes weeks to months. Until the fabric is covered, the device itself can form device-related thrombus (DRT). Labs therefore prescribe a protocol-specific sequence.

Classic Watchman teaching (example only, not an ARRT mandate): warfarin plus aspirin for an early window (often taught as about 45 days), then a TEE look for leak and DRT; if the seal is acceptable, transition to dual antiplatelet therapy, then aspirin long term. Some contemporary Watchman-class protocols use DAPT instead of warfarin from day one. Amulet-class programs often use DAPT then aspirin and may not mandate warfarin. Whatever the implanting service ordered is the regimen — the exam point is that some antithrombotic coverage continues after implant, not that you memorize an unpublished ARRT day-count. Do not tell a patient “the device means you never take a blood thinner again” on the table.

Complications and closure

Pericardial effusion / tamponade: the LAA wall is thin. Oversizing, deep sheath intubation, a wire perforation, or a rough transseptal produces bleeding into the pericardium. This can declare during the case or hours later. Echo now; pericardiocentesis ready; surgical backup if the hole is a torn appendage rather than a needle puncture. Chicken-wing and small-depth anatomy raise perforation risk when the sheath has nowhere to go.

Device embolization: undersized or poorly compressed device, released despite a failed tug test, or a shallow landing zone. The device may sit in the LA, LV, aorta, or beyond. This is a snare and surgical-backup problem, not “it will endothelialize wherever it landed.”

Stroke: missed LAA thrombus, air from sheath exchanges, debris, or later DRT if antithrombotics are skipped. Vascular complications are the large venous sheath (hematoma, fistula, rare AV fistula) plus any extra arterial line.

Closure of access is venous hemostasis (figure-of-8, manual pressure, venous closure device). Document distal pulses if an arterial line was also placed. Hybrid-OR backup is a local-program decision; tamponade and embolization still need an immediate echo-and-surgery path (14.1, 16.3).

Table: step / confirmation / disaster

Worked case

A 78-year-old with nonvalvular AF, prior recurrent GI bleeding on a DOAC, CHA2DS2-VASc that would otherwise warrant anticoagulation. CT and TEE: no thrombus, landing zone matches a Watchman-class size. Femoral venous access, TEE-guided inferior-posterior transseptal, sheath into the LAA, device at the ostium, tug test holds, only a trivial peri-device leak. Start the lab’s antithrombotic protocol — if that lab uses classic Watchman teaching, that example is warfarin plus aspirin then a surveillance TEE, then DAPT, then aspirin; it is not an ARRT-mandated recipe. If TEE had shown LAA thrombus, stop. If the tug test fails and the frame rocks, do not release. Sudden hypotension with a new effusion is tamponade, not a vasovagal from the venous stick. A device that has left the LAA on the next fluoro is embolization — snare/surgery, not “check it in the morning.”

Exam traps

• Closing an LAA that already contains thrombus.
• Treating LAA closure as optional extra hardware on every AF ablation.
• Skipping the tug test or ignoring a peri-device leak.
• Reciting the classic Watchman warfarin–DAPT–aspirin sequence as an ARRT mandate rather than an example protocol.
• Confusing Watchman/Amulet with a PFO/ASD double-disk or a MitraClip.
• Calling tamponade impossible because the stick was venous.