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AB C

Fig. 19.2 US-approved devices for ASD closure. (A) Amplatzer septal occluder (ASO). The device is manu- factured from nitinol mesh with Dacron inserts in the left and right atrial disc regions. There is a self-centering waist by which the device is sized. The left atrial disc is displayed on the right, and vice versa. (B) Amplatzer Cribriform device. Similar construction to the ASO. Left atrial disc on the right, and vice versa. (C) Gore Cardioform Septal Occluder device. Device is constructed of multiple nitinol wires with an ETFE (Gore-Tex) covering. Left atrial disc on the right and vice versa. [Not shown: Gore Cardioform ASD Occluder] (© Mayo)

TABLE 19.1 n Approved Devices for ASD Closure in the United States

Device Sizes Defect Sizes

Amplatzer ASD 4-38 mm Up to 38 mm Amplatzer Cribriform 18, 25, 35 mm Fenestrations ,35 mm Gore Cardioform Septal Occluder 15, 20, 25, 30 mm Up to 15-17 mm Gore Cardioform ASD Occluder 27, 32, 37, 44, 48 mm 8-35 mm

Procedural Imaging

Intraprocedural echo guidance can be performed with TEE or with intracardiac echo (ICE). The latter obviates the need for general anesthesia but does require additional venous access. Conﬁrmation of the defect size and rims is most important, and balloon sizing with a compliant sizing balloon may provide additional information on defect size if echo imaging is not adequate. During and after device deployment, careful examination of the device discs for proper positioning, lack of prolapse from the left atrium to right atrium, and evaluation of a residual shunt are mandatory.

Procedural Aspects

Femoral venous access is achieved; rarely does one need arterial access. An 8F or 10F ICE catheter is positioned in the mid-right atrium. The ASD is usually crossed with a balloon catheter

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and guidewire or occasionally a multipurpose catheter and guidewire. After heparinization to an activated clotting time (ACT) of 200 seconds or greater, an extra-stiff Amplatzer exchange wire is positioned in the left or right superior pulmonary vein, and a delivery sheath—and subsequently a closure device—is advanced across the atrial septum into the left atrium. The left atrial disc is deployed, the entire apparatus is pulled back against the atrial septum, and the right atrial disc is deployed. After echocardiographic imaging demonstrates suitable device position (i.e., no signiﬁcant residual edge shunting and no interference with adjacent cardiac structures), the device can be deployed.

Device sizing may be performed in several ways. Most defects are elliptical in shape. For defects of moderate size and well-established rims, dimensions may be measured echocardiographically in two planes, usually long and short axis. Alternatively, a “stop-ﬂow” technique may be used with a contrast-ﬁlled balloon inﬂated just enough to stop shunt ﬂow on the echocardiogram. The orthogonal dimensions of this balloon can be then measured ﬂuoroscopically and echocardiographically. It may be difﬁcult to measure the exact dimensions in larger defects or those with deﬁcient rims using the stop-ﬂow technique. Three-dimensional echocardiographic imaging performed preprocedurally may be useful in these patients. An ASO of 2 to 6 mm larger than the defect diameter is selected, usually reserving the larger size for defects with ﬂoppier or thinner rims. The Amplatzer Cribriform Occluder has no centering component and must be placed in a fenestration, which allows coverage of other nearby defects; therefore the echo should be used to measure the maximum distance between fenestrations, and a device larger than this dimension should be chosen (with the largest device being 35 mm). The Gore Cardioform Septal Occluder device is similar in function and could be placed in a fenestration or in a defect just over half of its diameter (i.e., 30-mm device for 17- to 18-mm defect). The Gore Cardioform ASD Occluder is placed similarly to the ASO.

Difﬁcult deployment may occur in patients with deﬁcient rims, especially the anterior or retroaortic rim. Alterations in angulation of the device using a modiﬁed delivery catheter or placement of the guidewire in the right upper pulmonary vein may be required. There are other various techniques, including pulmonary vein deployment of the left atrial (LA) disc, and balloon-assisted technique. The assistance of an experienced pediatric interventional cardiologist may be useful with larger defects. Proctoring will be necessary for the initial use of these devices.

COMPLICATIONS

Deairing a long sheath placed in the left atrium can be problematic, but this long sheath is required for the Amplatzer devices. Air embolism usually manifests as chest pain and ST-segment deviation from air entering the right coronary artery or, less commonly, as neurologic symptoms. An air embolus can be avoided by careful catheter ﬂushing and avoidance of developing an air– ﬂuid level in the catheter hub. This is best achieved by keeping the hub of the catheter low on the table. A thrombus developing on the guidewire or device during implantation can be avoided by adequate anticoagulation. Atrial ﬁbrillation can occur during device implantation or shortly thereafter and is usually self-limited. If spontaneous resolution does not occur, cardioversion should be done.

Device embolization can occur with larger defects, particularly when the rims are small, absent, or ﬂoppy. Embolization can occur either into the left atrium and arterial system or into the pulmonary artery. It is best avoided by proper device sizing and careful inspection of the device seating before full release after deployment. Embolized devices can be retrieved with a snare and large-bore sheath in most cases. Typically, a sheath at least 2F larger than the

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original delivery system will be needed, and a bevel cut into the tip may facilitate bringing the snared device into the retrieval sheath. Device erosion is a rare complication of the Amplatzer device. It occurs in 0.1% to 0.2% of cases, and is likely related to apposition of the LA disc against the LA wall or aorta. There is some relation to device oversizing and deﬁciency of the retroaortic rim, and careful imaging before and after deployment is warranted. Figs. 19.3 to

19.5 and Video 19.3 demonstrate ASD closure.

Follow-Up

Our current practice is an outpatient or one-night hospitalization with rhythm monitoring and transthoracic echocardiographic imaging after device placement to evaluate device position and to rule out pericardial effusion. Aspirin therapy and endocarditis prophylaxis are recommended for 6 months. Patients then are typically followed up at 6 months with another limited echocardiographic examination and then annually.

Procedural Steps for ASD Closure

Fig. 19.3 Closure of secundum ASD. (A) Intracardiac echo of a patient with secundum atrial septal defect (arrow- heads). INF, Inferior; LA, left atrium; RA, right atrium; SUP, superior. (B) Intracardiac echo, color ﬂow image. Defect

measures 1.26 cm. Left-to-right shunt shown in red. (C) Balloon sizing. Arrowheads denote indentation of balloon. (D) Left atrial disc deployment.

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E F

Fig. 19.3 cont’d

device deployment. Device still attached to delivery cable. (G) Device released. Properly positioned. (© Mayo)

(E) Improper positioning of Amplatzer device. Right atrial disc is partially in left atrium. (F) Proper

Fig. 19.4 Deployment of Gore Cardioform device. (A) Left atrial disc deployed. (B) Device drawn toward atrial septum. (C) Right atrial disc deployed. (© Mayo)

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Fig. 19.5 Deployment of Amplatzer Septal Occluder in atrial septal defect with deﬁcient aortic rim. (A) Intracardiac echocardiogram (ICE) showing secundum atrial septal defect. A posterior rim is seen, but there is no tissue rim adjacent to the aorta. (B) Color ﬂow images showing left-to-right shunt. (C) Measurement of the defect between the posterior rim and the aorta 5 1.7 cm. (D) Balloon sizing shows a dimension of 2.4 cm. (E) Placement of a 26-mm Amplatzer Septal Occluder. (© Mayo)

Patent Foramen Ovale

INDICATIONS

Results of recent randomized trials demonstrate that closure of a patent foramen ovale (PFO) may be indicated in selected patients with unexplained stroke (Table 19.2). Before considering PFO device closure, common causes of stroke such as carotid stenosis, thrombotic diathesis, arterial dissection, and subclinical atrial ﬁbrillation must be excluded. In our practice, a neurologist is involved in shared decision-making regarding closure versus antiplatelet or anticoagulant therapy.

Fig. 19.6 demonstrates our usual approach.

Orthodeoxia is another indication for PFO device closure, as well as selected patients with

pacemaker lead debris who have planned pacemaker extraction.

19—ATRIAL SEPTAL DEFECT, PATENT FORAMEN OVALE, AND ATRIAL SEPTOSTOMY 231

*Recommended TEE to MRA imaging of carotid and Duple Thrombophilia testing to e Exter

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TABLE 19.2 n Recent Randomized Trials of PFO Device Closure for Secondary Prevention of Stroke

Trial Device Recurrent Stroke (per

100 Patient-Years)

RESPECT LT Amplatzer PFO 0.58 vs. 1.1 45 5.9 REDUCE Gore Cardioform 1.4 vs. 5.4 25 3.5 CLOSE Multiple 0 vs. 6 17 5.4

F/U, Follow-up; NNT, number needed to treat.

NNT Mean F/U

(Years)

PFO identified by TEE

Hx stroke, TIA

No intervention

Ye s

Neurology consult:

Stroke location c/w embolism

No Ye s

2° prevention

per neurologist

Treat cause

2° prevention

evaluation:

evaluate intracardiac or aortic embolic sources

x scan of lower extremities and rule-out DVT

nal or implantable cardiac monitoring to exclude atrial fibrillation

Presence of large R → L shunt (> 30 microbubbles) or atrial septal aneurysm increase likelihood of benefit of device closure

vertebral arteries

xclude thrombotic diathesis

Fig 19.6 General approach to PFO in the adult.

Stroke cause other

than PFO identified*

Consider PFO device closure

Shared decision making

with neurologist

DEVICES

Approved devices include the Amplatzer PFO Occluder and the Gore Cardioform Septal Occluder (Table 19.3).

PREPROCEDURAL IMAGING

Usually a PFO will be ﬁrst diagnosed by echocardiography and bubble study, with documentation of right-to-left shunting after Valsalva release. It is important to determine the exact

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TABLE 19.3 n Approved Devices for PFO Closure

Amplatzer PFO Occluder 18, 25, 35 mm Gore Cardioform Septal Occluder 15, 20, 25, 30 mm

location of observed right-to-left shunting—intrapulmonary versus across the PFO. This can be achieved by transesophageal imaging the PFO and directly observing the passage of bubbles from right to left. It is also important to judge the adequacy of the Valsalva response. This will be sufﬁcient if the atrial septum bows from the right to left side during Valsalva release. In heavily sedated patients, this may not occur, and subsequent transthoracic bubble study may demonstrate right-to-left shunting that was not revealed during the TEE because of sedation.

PROCEDURAL IMAGING

Guidance during device closure is accomplished with either TEE or ICE. We typically use an ICE catheter as described earlier. In addition to inspection of the PFO and adjacent atrial septum for fenestrations, we may perform a bubble study from the right femoral vein. Fluoroscopic imaging views are similar to that for ASD described earlier.

PROCEDURAL ASPECTS

The atrial septum can usually be crossed with a balloon catheter and soft-tipped straight guidewire. Often the straight wire will cross the defect without difﬁculty. If the defect is hard to cross, we will use a 5F multipurpose diagnostic catheter and position it against the atrial septum within the PFO tunnel and then cross with a guidewire. ICE is useful for guiding the catheter across the defect. Following this, the catheter is positioned into a pulmonary vein and an exchange-length 0.0350 stiff guidewire is positioned. The delivery sheath or catheter/ device is advanced and the device positioned across the PFO. With careful echocardiographic guidance, the LA disc is deployed, drawn back against the atrial septum, and the right atrial disc deployed. Once the ICE/TEE conﬁrms satisfactory device position, the device can be released.

With regard to device sizing, we typically do not perform balloon sizing of a PFO. We take

measurements of the fossa ovalis in long- and short-axis intracardiac imaging views. We avoid placing a device larger than the distance between the aorta and the free wall in the short-axis view, where the distance is typically smallest. For the Gore Cardioform Septal Occluder, in most smaller-bodied individuals, a 25-mm device size is sufﬁcient. For larger individuals and those with a very mobile atrial septum or a large excursion of the PFO ﬂap, we place a 30-mm device. In the patient with orthodeoxia or those with a wide PFO diameter and redundant septum, the use of a compliant sizing balloon, then selecting an ASO of similar diameter to that of the balloon waist should be considered; the central waist of this device ﬁlls the defect to provide closure and prevent further signiﬁcant right-to-left shunting. Figs. 19.7 and 19.8 and Videos 19.1, 19.2, and 19.4 demonstrate device closure of a PFO.

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Fig. 19.7 Closure of tunnel-type PFO with lipomatous septum secundum. (A) ICE imaging. Arrowheads demonstrate the “tunnel,” which represents overlap of the septum primum and septum secundum. This distance is approximately 2.5 cm. (B) Placement of a Gore Cardioform Septal Occluder device. The arrowheads demonstrate the edges of the device. Complete coverage of the lipomatous septum is achieved, with no residual shunting. (© Mayo)

Fig. 19.8 Closure of the atrial septum in a patient with orthodeoxia/platypnea. This patient presented with dyspnea and arterial desaturation. (A) Upright bubble study. The left ventricle is completely opaciﬁed. (B) Amplatzer Septal Occluder implanted. Arrowheads delineate the edges of the device. (C) Upright bubble study with coughing. No residual shunting is present. The patient’s dyspnea and arterial desaturation were immediately corrected. (© Mayo)

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COMPLICATIONS

These are similar to those observed for ASD closure. Device embolization is extremely rare. There is a risk of permanent atrial ﬁbrillation of less than 2%.

FOLLOW-UP

This is similar to ASD device closure.

Atrial Septostomy

INDICATIONS

In adult patients, atrial septostomy may be performed as part of another procedure (i.e., mitral valve-in-valve placement) or occasionally as palliation in patients with high right atrial pressures, such as pulmonary hypertension with low cardiac output, or those with elevated LA pressure such as patients with stiff LA syndrome. The latter two situations are not guideline-recommended indications, and the use of this procedure must be carefully considered before it is employed. The assistance of a pulmonary hypertension specialist or heart failure specialist in evaluation of the patient is recommended.

DEVICES

We use a number of different peripheral high-pressure angioplasty balloons, typically 8 to 16 mm in diameter.

PROCEDURAL IMAGING

We use ICE for imaging of the atrial septum in multiple views, as described earlier. This patient population can be hemodynamically unstable, so the use of ICE avoids the discomfort of TEE and the risk of general anesthesia. The best view showing the fossa ovalis and thin portion of the atrial septum (septum primum) is selected for our working view. Biplane fluoroscopy can be utilized, or simply monoplane with an anteroposterior (AP) projection.

PROCEDURAL ASPECTS

We perform a transseptal puncture as described elsewhere in this chapter. For the septostomy, one should avoid traversing a PFO, if present. After this, a moderately stiff exchangelength guidewire is placed across the septum. Utilizing ICE guidance, we place a dilating balloon across the ASD and perform several inﬂations. Typically, a 14- to 16-mm-diameter balloon will produce an ASD of approximately 6 to 8 mm. Fig. 19.9 demonstrates an atrial septostomy.

COMPLICATIONS

If the transseptal puncture site has been determined correctly, complications will be minimal but similar to those observed any time transseptal access is performed. Follow-up depends on the clinical situation, but typically we do bubble study echocardiograms in follow-up to determine continued patency of the septostomy, especially if performed to create a right-to-left shunt.

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Fig. 19.9 Atrial septostomy in a patient with stiff left atrial syndrome. The patient presented with dyspnea after multiple catheter ablation procedures. Left atrial pressure was elevated with a large V wave. (A) ICE image of atrial chambers. Transseptal puncture has been performed in the midportion of the atrial septum. An Amplatzer extra-stiff guidewire has been placed in the left superior pulmonary vein. The atrial septum has been dilated with an Inoue dilator. There is left-to-right shunting around the guidewire (color jet). (B) ICE image, 10 3 20 mm Mustang balloon inﬂated across the atrial septum (arrowheads). This did not result in a sufﬁciently sized atrial septal defect. (C) Initial inﬂation of a 15 3 40 Tyshak balloon. Arrowheads show waist on balloon. (D) Final inﬂation of this balloon. (E) The resultant atrial septal defect was approximately 1.5 3 0.7 cm. The patient had an excellent clinical response with reduction of dyspnea and sustained lowering of mean left atrial pressure. (© Mayo)