Transcatheter therapy for Lutembacher's syndrome: The road less travelled.

An 18-year-old male with Lutembacher's syndrome underwent balloon mitral valvotomy (BMV) and device closure of the atrial septal defect (ASD). BMV necessitated technical modification of taking the Inoue balloon over the wire (OTW) into the left ventricle (LV). The procedure was complicated by slippage of ASD device into the right atrium, which was managed successfully by percutaneous retrieval, and deployment of a larger device. The case highlights the challenges associated with the seemingly easy transcatheter therapy for this disease entity.

INTRODUCTION

Lutembacher's syndrome, a combination of congenital defect in the atrial septum and acquired mitral stenosis (MS) with its unfavorable long-term natural history[1] has traditionally been corrected by surgical treatment. Due to widespread acceptance of transcatheter therapies for MS and ASD and its attendant safety, less morbidity, and cosmetic advantage, percutaneous treatment for Lutembacher's syndrome seems an attractive and feasible alternative. Although definitive percutaneous treatment has been reported in the literature,[234] none of these reports except for a recent one[4] have highlighted the challenges associated with simultaneous catheter-based treatment of this combination cardiac anomaly.

We report a case of percutaneous treatment for Lutambacher's syndrome, with the attendant technical difficulties faced in stabilizing the Inoue balloon across the mitral valve (MV) and management of post-procedure malpositioned ASD device.

CASE REPORT

An 18-year-old male, presented with history of dyspnea on exertion New York Heart Association (NYHA) class II. Physical examination revealed loud first heart sound, wide and fixed split second heart sound, mid diastolic murmur at the apex, and lower left sternal border with grade 4/6 ejection systolic murmur in the left second parasternal region. Electrocardiogram (ECG) showed incomplete right bundle branch block with right atrial enlargement. Chest X-ray findings were increased pulmonary vascular markings with prominent right pulmonary artery. Transthoracic echocardiography (TTE) showed a 27 mm ostium secundum ASD with severe rheumatic MS [Figure 1]. The mitral valve area (MVA) was 0.67 cm2 by planimetry. Color flow mapping revealed a left-to-right shunt across the ASD. As both the ASD and MS appeared suitable for percutaneous treatment, concurrent transcatheter therapy was planned.

Figure 1

Two-dimensional transthoracic echocardiogram in apical four-chamber view showing a 27 mm atrial septal defect (horizontal arrow) and stenotic mitral valve (vertical arrow)

Patient received 300 mg of clopidogrel and 325 mg of aspirin 1 day prior to procedure. After antibiotic prophylaxis, right femoral arterial and venous access was obtained, and 5,000 units of heparin administered. Right and left heart catheterization with oximetry run confirmed a left to right shunt with step up at the atrial level with Qp/Qs of 5.37 as measured by Fick's principle. The mean left atrial pressure and transmitral gradients were relatively low, in spite of significant MS.

Balloon mitral valvotomy (BMV) was first undertaken. Multiple attempts with standard Inoue technique proved futile with repeated jumping of Inoue balloon back into the right atrium (RA) and right ventricle (RV). Hence, an over -the -wire (OTW) technique was adopted with the available hardware on shelf. The mitral valve (MV) was crossed using a balloon floatation catheter (Swan Ganz) and an Inoue wire was placed directly into the LV. However, an attempt to introduce the Inoue balloon over the Inoue wire failed because of poor support. Modifying OTW technique, we recrossed the MV with a balloon floatation catheter, parking an Inoue wire directly into the left ventricle (LV). With the Inoue wire in situ, the Swan Ganz catheter was removed and a Mullins sheath was introduced into the LV. With adequate support provided by Mullins sheath, the Inoue wire was exchanged for a J tip Amplatz extra stiff wire (ESW). After removing the Mullins sheath, an Inoue balloon was successfully introduced into the LV over the ESW. With Inoue balloon stabilized in the LV cavity, the ESW was changed to Inoue wire for better conformation to the LV anatomy and provide safe support to Inoue balloon during mitral valvotomy [Figure 2]. The MV was successfully dilated using a 26 mm Inoue balloon with abolition of the transmitral gradient and a MVA of 1.8 cm2.

Figure 2

Inoue balloon positioned in the left ventricular cavity over the Inoue wire before mitral valvuloplasty

After successful BMV, ASD device closure was undertaken. Based on our experience of device closure of ASDs without balloon sizing under trans-thoracic (TTE) guidance in young patients, we decided to deploy a 30 mm Amplatzer (AGA Medical, Golden Valley, MN) ASD device under TTE guidance. Postprocedure TTE showed a well-deployed device across the ASD. Twelve hours postprocedure TTE showed a malpositioned device, which was confirmed later on transesophageal echocardiography (TEE) [Figure 3]. After arranging for full surgical backup, percutaneous retrieval of malpositioned ASD device was undertaken under cinefluroscopic and TEE guidance. Intentional bevel was created at the end of a 12 French Amplatzer sheath and a 1-cm Amplatz GooseNeck snare (Amplatz, ev3 Inc., Phymouth, MN, USA) was chosen with intention to grasp the microscrew of the right atrial disk of the ASD device. Using alternate orthogonal views to align the snare in the plane of the ASD device, the device was successfully pulled from the RA into the inferior vena cava below the kidneys and retrieved through the femoral sheath [Figure 4a–c]. Careful reassessment of ASD diameter under TEE guidance showed a procedural diameter of 30 mm and total interatrial septal length of 52 mm. Final ASD device closure [Figure 5] was done with a 36 mm Heartr™ atrial septal occluder device (Lifetech Scientific Inc., Shenzhen, China). There were no further postprocedural complications and patient has done excellently with no clinical sequelae at 16 months follow-up.

Figure 3

Transesophageal echocardiography showing malpositioned Amplatzer device into the right atrial cavity

Figure 4

Percutaneous retrieval of malpositioned atrial septal defect (ASD) device under cinefluroscopic and transesophageal echocardiography (TEE) guidance. (a) The right atrial disk microscrew mechanism being snared with a 1-cm Amplatz GooseNeck snare. (b) The device being pulled into the 12 French Amplatzer sheath with intentional bevel at the end. (c) Successful retrieval of the device from the right atrium into the inferior vena cava (causing the device to elongate) below the kidneys and through the femoral sheath.

Figure 5

Lateral projection showing successful final deployment of a 36 mm Heartr™ atrial septal occluder device

DISCUSSION

With tremendous refinements in interventional technology, structural heart disease interventions have grown into a subspecialty of its own. With durable mid- and long-term results associated with percutaneous treatment for MS and ASD, Lutembacher's syndrome lends itself as a perfect recipe for percutaneous therapy.[234] However, the interventional procedure is, not simply a combination of two simple procedures, that is, BMV and ASD device closure, as the coexisting anomalies change the cardiac anatomy in a way that makes catheter manipulations complex.[4] Contrary to perception that presence of ASD foregoes the need for atrial septal puncture and hence simplifies BMV, the large defect provides excessive space for free floatation of the Inoue catheter which makes the balloon catheter unstable, posing technical difficulties in stabilizing it across the stenosed MV. This warrants use of alternative methods for MV crossing. OTW technique has been described as an alternative for MV crossing in difficult cases.[567]

Our case is interesting because we failed to cross the MV even with OTW technique. This may be related to the inadequate support provided by a small LV cavity resulting from LV underfilling consequent to significant MS augmenting the left to right shunt across the ASD with enormous RV volume overload. The OTW technique was subsequently modified in order to accomplish successful MV crossing. Though we initially crossed the MV with a balloon floatation catheter, parking an Inoue wire directly into the LV, the Swan Ganz catheter was exchanged to a Mullins sheath to provide adequate support to introduce the ESW into a small LV cavity. Once the Inoue balloon was successfully introduced into the LV over the ESW, the ESW was changed to Inoue wire for better conformation to the LV anatomy.

ASD device embolization has been reported in 0.5-1.2% for Amplatzer septal occluder and in 70% of cases it could be retrieved successfully.[89] We were fortunate that our device was malpositioned rather than embolized. The percutaneous retrieval of an ASD device involves snaring the device by catching the microscrew and withdrawing the whole device into the sheath.[9] Measures that facilitate entrance of the snared microscrew into the sheath include cutting a bevel at the tip of the sheath and rotating the sheath so it will engage the screw better.[89] In addition use of a stiff sheath (e.g., Cordis Brite Tip or Cook Flexor, Cook Cardiology, Bloomington, IN, USA) with the sheath size approximately two French sizes larger than the required implant sheath is recommended.[9] It is important to understand that snaring the device in any location other than the microscrew will not permit the device to be pulled into the sheath.[9]

The majority of embolizations are a function of either undersized devices or of ASDs with inadequate rims.[8] The device malpositioning in our case seems related to undersizing as we initially deployed the device under TTE guidance which underestimated the size of the ASD. Though balloon sizing of the defect has been regarded as an integral part of transcatheter closure of ASD, there has been a recent trend towards transcatheter closure of ASDs without balloon sizing.[1011] TTE with its advantages of not requiring general anesthesia and the convenience of presenting multiplanar views of the heart can be sufficient for the assessment of the ASDs.[1213] In addition there is good linear correlation between TTE measurement of the defect and balloon stretched diameter.[14] However, as reported by Li et al., TTE was most efficient in predicting device size for defects smaller than 20 mm.[12] This surely led us to make a wrong decision regarding device sizing with its attendant catastrophe.

TEE with its higher resolution is more appropriate for larger defects as the rims are usually weak, soft, and floppy; and the measurement of accurate defect diameter might be a more challenging task under TTE. However, anatomical ASD diameter, measured with TEE using edge-to-edge defect borders still tends to underestimate the device size. Hence, we utilized the procedural diameter measured using the maximal steadier rim border (thickness ≥2.5 mm) distance on TEE images as proposed by Carcagni and Presbitero[15] during redeployment of ASD device as it correlates well with stretched balloon diameter (SBD) in adults. Adding 4-6 mm to TEE diameter gives a good estimate of the stretched diameter in most cases,[11] which made us choose the final device diameter. In fact, oversizing of the device should be the rule in this condition.

CONCLUSION

Though percutaneous therapy for Lutambacher's syndrome is an attractive and feasible alternative to surgery, the BMV procedure can be complex with difficulties in stabilizing the Inoue balloon across the stenosed MV. In addition a careful assessment of device size utilizing either TEE procedural diameter or conventional balloon sizing and choosing a larger device is highly recommended to prevent complications like device embolization. As this is a road less travelled, prior anticipation of the difficulties to be encountered along with a skillful approach and familiarity of operators with device retrieval techniques improve the chances of success.