Tools for Echocardiographic Calculations

Muhamed Saric, MD, PhD
New York University



FDA Indication for Watchman LAA Occluder

The WATCHMAN Device is indicated to reduce the risk of thromboembolism from the left atrial appendage in patients:

bulletWith non-valvular AF who are at increased risk for stroke and systemic embolism based on CHADS2 or CHA2DS2-VASc scores;
bulletAre deemed by their physicians to be suitable for warfarin; and
bulletHave an appropriate rationale to seek a non-pharmacologic alternative to warfarin

Watchman Device Sizes

bulletWatchman comes in 5 different sizes, 3 mm apart
bulletSize is based on the device diameter
bulletAvailable sizes 21, 24, 27, 30, 33 mm
bulletImplanted Watchman should be appropriately oversized for a given LAA diameter

LAA Anatomic Exclusion Criteria

bulletLargest LAA orifice diameter < 16.8 mm OR > 30.4 mm
That is, the largest LAA orifice size cannot be smaller the smallest diameter required for the 21-mm Watchman and cannot be larger than the largest diameter required for the 33-mm Watchman.

LAA diameter and depth are measured on TEE at 0, 45, 90 and 135 degrees. The largest diameter and depth obtained from these 4 angles is then used. At 0 degrees, measure from left coronary artery to 2 cm from tip of LAA coumadin ridge. At other angles from top of MV annulus to 2 cm from tip of LAA coumadin ridge.
bulletLAA depth < Largest LAA orifice diameter
That is, a patient's LAA cannot be too shallow.
bulletThe depth of the secondary LAA lobe (if present) from the LAA orifice plane < 1 cm
That is, the secondary lobe cannot be too close to the LAA orifice.
bulletPresence of intracardiac thrombus or LAA dense smoke


Other Exclusion Criteria

bulletAtrial septal aneurysm excursion distance > 15 mm
bulletAtrial septal aneurysm length > 15 mm
That is, atrial septal aneurysm may be considered an indication for anticoagulation even if LAA is excluded.
bulletLarge interatrial shunt
This is a semi-quantitative criterion; no specific definition for a large shunt on color Doppler or after agitated saline injection is given.
bulletMobile aortic plaque > 4 mm
bulletMitral stenosis (MV area < 1.5 cm2)
That is, the patient cannot have significant mitral stenosis.
bulletPericardial effusion with thickness > 2 mm
That is, a patient cannot have more than a trivial pericardial effusion).


Watchman Device Sizes & Compression Values

  Compressed Diameters
Watchman Diameter Minimum Maximum
21 16.8 19.3
24 19.2 22.1
27 21.6 24.8
30 24.0 27.6
33 26.4 30.4


Medical Therapy Post Watchman Implantation

bulletFirst 6 weeks - Warfarin or NOAC
bulletFrom 7th week to 6 month - Dual antiplatelet therapy
bulletAfter 6 months - Aspirin for life

Watchman Screening Sheet

bulletWatchman Screening Sheet.pdf