Fig. 9.1
(a) Pericardial effusion and cardiac tamponade is the most common complication of LAA closure. (b) The LAA is a delicate cardiac structure that can be easily perforated. Any wire (even a J wire) that is pushed out of a catheter can perforate the LAA if the catheter is against the LAA wall. Unsheathing and fluoroscopic guidance is recommended. The SafeSept wire can be used for a safer transseptal puncture
9.1.1.1 Prevention
By using TEE, the baseline status of pericardial space should be defined in order to differentiate an acute from chronic pericardial effusion.
Optionally, two packs of RBC may be cross-matched before the procedure.
LAA closure in a patient receiving OAC therapy should be avoided.
During transseptal puncture, all available safety measures should be used, especially when encountering a very rigid or aneurysmal interatrial septum. For example, a coronary angioplasty wire can be used. The stiff back-end of the wire is used to puncture (inside the TSP needle—not to be advanced more then 3–5 mm in the left atrium) and then the floppy front of the wire can be advanced in the left upper pulmonary vein (LSPV) to facilitate safe introduction of the TSP sheath (over-the-wire). In case of a rigid septum, the dilator and sheath can be advanced over the introducer wire (0.032″) that has been carefully placed in the LSPV.
Angiography of the LAA should be performed via a pigtail catheter (inside the TSP sheath) or via the side arm of the TSP sheath. The latter allows for enhanced contrast injection in high pressure, which can fully dilate a partially collapsed LAA (especially a large LAA). Power injection should be avoided and checking for back-flow bleeding before injecting can prevent LAA wall trauma from a vigorous contrast injection.
Since the LAA is a blind-ended structure, any wire should be advanced cautiously and only under fluoroscopic guidance. Note that even a soft J wire can easily perforate the LAA when it is pushed out a catheter facing the LAA wall (Fig. 9.1, panel b).
Early detection of a pericardial effusion can be life saving so close patient monitoring is required. An invasive pressure line (i.e. radial) can allow for immediate recognition of hemodynamic compromise due to pericardial effusion. The TEE operator should check periodically for the presence of a new effusion.
When deep intubation of the LAA is needed a pigtail catheter should be used inside the TSP or the delivery sheath.
A pericardial drainage kit should be readily available in the Cath Lab.
When available, a cardiac surgeon should be notified about a planned LAA closure procedure.
Watchman implantation: a very distal release in a tiny lobe (Fig. 9.2) where the device cannot unfold properly also leaving a large gap (Fig. 9.2b, c, d) has a high risk of causing a pericardial effusion.
Fig. 9.2
Pericardial effusion following distal release (a) The Watchman delivery sheath is positioned deep in the most anterior lobe. The 27 mm device is released (b) but leaves a huge gap towards the inferior lobe (c, d). The ridge between the lobes which is not visible on TEE (see Fig. 8.1) prevents the device taking the typical Watchman configuration. The device is compressed massively in its distal part (b). This situation (device release too distal, compression >70%) comes with a particular high risk of pericardial effusion
9.1.1.2 Treatment
A rapidly accumulating pericardial effusion is an emergency situation because it can lead to tamponade and cardiac arrest within a few minutes. The following measures should be applied.
If the device is closing the LAA effectively, it should be released since this will minimize leakage from the LAA (Fig. 9.3).
LAA closure should be completed rapidly if possible. Successful LAA closure either with an Amplatzer Amulet or a Watchman device will often seal or at least partially seal the source of hemorrhage.
echo diagnosis should be made by comparing baseline images to the current situation (Fig. 9.4a, b).
Pericardiocentesis should be performed once the effusion has reached approximately 1 cm (Fig. 9.4b). Puncture is easily performed with a standard long needle from a pericardial puncture set with small amounts of contrast medium to visualize successful location of the epicardial space. (Fig. 9.4c) Very early puncture has an increased risk of accidental right ventricular puncture. Late puncture takes the risk of the patient becoming hemodynamically stable.
6F Pigtail via a standard femoral sheath is recommended. (Fig. 9.4d)
Ongoing hemorrhage may be managed by autotransfusion using a standard red blood cell transfusion system and a 50 ml syringe
Reversal of heparinization with protamine risks thrombus formation in the epicardial space without stopping bleeding; the pigtail clots but the effusion continues to enlarge. This regularly ends in a very unstable situation which requires immediate surgery and is responsible for the mortality in this setting. Usually the bleeding reduces after around 10–15 min of drainage even without protamin.
In case of massive hemorrhage, call for emergency surgery preparation.
Most pericardial effusion’s can be managed by interventional pericardiocentesis. Usually drainage is required for around 24–48 h.
Fig. 9.3
Successful closure of the LAA with a more proximal release. After partial recapture the device is release more proximal finally taking the classical Watchman strawberry-like configuration (a, b). Echo confirms good compression and successful closure without any leaks (c, d)
Fig. 9.4
Pericardial effusion following the first distal Watchman release; successful drainage. Parallel to LAA closure demonstrated in Figs. 8.1–8.3 the development of a hemodynamically relevant pericardial effusion is observed (a, b). A pericardial puncture under angiographic guidance is performed from a subxiphoid access (c) using contrast to visualize correct positioning of the needle. A 6F pigtail is placed in the pericardial space (d). This drained around 200 cc of blood. No protamine is given since this would lead to clotting of the pericardial effusion without sealing the perfoaration resulting in impaired effective pericardial drainage.
9.1.2 Thrombus Formation
Thrombus formation during LAA closure can occur within seconds and can jeopardize the whole procedure. Incomplete heparinization is the most common reason for thrombus formation (Fig. 9.5).
Fig. 9.5
(a) Thrombus is not visible on fluoroscopy unless contrast is injected. However, as this may result in thrombus embolization to the periphery it should be avoided. (b) Fortunately, to date delivery wire thrombosis has not been associated with procedural stroke as the thrombotic material is attached quite firmly to the wire. In any case, careful heparinization with an ACT > 250 s (or even 300 s) is mandatory. (c) TEE surveillance is invaluable in the early detection of thrombus in the LAA, on the LAA closure device or delivery system
9.1.2.1 Prevention
ACT should be periodically checked (every 20–30 min) and corrected.
ACT should be between 250–300 sec before introducing any material in the left atrium.
In the case of a difficult TSP, a thrombus can form on the TSP needle in the right atrium. Therefore many operators prefer to administer half-dose of heparin before TSP and complete heparinization immediately after crossing the septum.
Some patients may have a higher risk for thrombosis due to very large left atria, chronic AF with spontaneous contrast on TEE, blood dyscrasias or resistance to heparin and, therefore, require higher doses of heparin. On the other hand, there is always a theoretical risk of bleeding, which is commonly the indication for LAA closure, so aggressive heparinization may be harmful. Time is probably one of the most important elements: if working on a low ACT range is mandatory, the intervention should be done as speedily as possible.
Thrombus is usually not visible on fluoroscopy so TEE surveillance is important for early detection.
For the Amplatzer devices, the most common surface a thrombus may be formed on is the distal part of the delivery wire. Fortunately, when a thrombus forms there it is well attached and does not easily embolize to the periphery.
If the patient is not sufficiently heparinized, thrombus may develop inside the Watchman sheath. If after the transseptal puncture and sheath exchange, backbleeding is unsuccessful, the sheath should be removed and flushed outside the body.
9.1.2.2 Treatment
Depending on its position, size and mobility, thrombus aspiration via a large sheath may be attempted.
Local thrombolysis with alteplase has been reported.
If available, it is advisable to use a cerebral protection device before starting any manipulations.
The presence of thrombus in the LAA despite adequate OAC (Fig. 9.6a) is a challenging situation (malignant LAA). At first presentation, the patient should be treated with low molecular weight heparin for 4–6 weeks.
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