Two-Stent Telescoping Technique for Securing an Atrially Embolized Venous Stent

ABSTRACT: Coronary sinus stenosis or atresia is a rare problem in congenital heart disease. It is sometimes associated with ventricular dysfunction. In this setting, relief of the obstruction may improve myocardial perfusion and contractility. During percutaneous stent deployment within the coronary sinus, distal embolization of the stent into the atrial chambers occurred. The patient had double inlet left ventricle, severe ventricular dysfunction, interrupted IVC, mechanical aortic valve, and a Fontan circulation. The intervention was performed as a rescue procedure prior to transplantation referral. In this report we describe use of telescoping technique, i.e., deploying the distal end of a long stent within the embolized stent while traversing its proximal end across the stenosed coronary sinus ostium. This secured the embolized stent and at the same time relieved the coronary sinus stenosis.

J INVASIVE CARDIOL 2010;22:E168–E170

Key words: coronary sinus obstruction, stent migration, stent retrieval, stent crimping, telescopic technique

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Coronary sinus stenosis or atresia is a rare problem in congenital heart disease sometimes associated with ventricular dysfunction. In this setting, relief of the obstruction may improve myocardial perfusion and contractility. Case Report. A 22-year-old male with a heterotaxy syndrome, double inlet left ventricle, interrupted aortic arch, subaortic stenosis, and azygos continuation of an interrupted inferior caval vein, had initial repair of the interrupted aortic arch, with pulmonary arterial band during infancy. This was followed by a Damus-Kaye-Stansel procedure in which the pulmonary trunk was anastamosed to the aorta in an end to side fashion. At the age of 9 years he underwent his first Fontan procedure, in which his superior caval vein was connected to the right pulmonary artery which resulted in total systemic venous return to the pulmonary circulation, i.e., a Kawashima type procedure, while his hepatic veins continued to drain to the right atrium directly. At the age of 16 he underwent completion of his Fontan with insertion of a 22 mm Dacron conduit from the hepatic veins to the underneath surface of the proximal left pulmonary artery following an entirely extra-cardiac fashion. During the same surgery he also had replacement of the native pulmonary valve with a mechanical prosthesis for regurgitation. At age 20 he required percutaneous stenting of Fontan conduit stenosis. At most recent presentation he complained of marked effort related dyspnea and chest pain. Two-dimensional echocardiography revealed severe systemic ventricular dysfunction and subsequent diagnostic catheterization revealed critical coronary sinus ostial stenosis and proximal dilation of the sinus, most likely congenital in origin. There was minimal run off to the right superior caval vein as the inter-connecting vein was rather small. Balloon occlusive angiography within the left superior caval vein demonstrated a pin point stenosis at its ostium at the communication site to the atrial chambers (Figure 1). His Fontan pressures were acceptable at 11 mmHg. In view of his poor ventricular function he was deemed not a surgical candidate and it was felt that ultimate transplantation was his only real option. Percutaneous relief of the coronary sinus stenosis was felt to be a reasonable 1st line therapeutic strategy. We consequently proceeded with balloon dilatation of the coronary sinus using a 16 mm x 3 cm Cristal balloon. (Balt Extrusion, Montmorency, France) with complete relief of waist. This procedure was successful and repeat angiography demonstrated a good result. The day following the procedure he desaturated profoundly due to steal from the left SVC to the coronary sinus and therefore the proximal left SVC was occluded with a 9 mm Amplatzer vascular plug. Saturation increased from 84 to 89% and mean left SVC pressure was 5 mmHg. However in the ensuing weeks he had progressive angina and worsening of his effort tolerance. He was therefore recatheterized with a view to stenting his coronary sinus ostium. Venous access was obtained via the left internal jugular vein using a 6 French (Fr) short sheath. The left superior caval vein and coronary sinus were then cannulated initially with a 0.035″Terumo exchange length wire (Terumo Interventional Systems, Somerset, New Jersey) and a 4 Fr Gensini catheter (Cordis Corp., Miami, Florida). The Terumo was exchanged for a 0.035″ ordinary guidewire which was positioned in the atrial chambers. The guidewire was manually pre-shaped such that 3 large loops lay in the atria for wire stability. A 10 Fr Mullins (Bard, Billerica, Massachusetts) sheath was then passed through the distal obstruction into the atrial chambers. A PG2910P Cordis Genesis Palmaz stent (Johnson & Johnson Interventional Systems Co., Warren, New Jersey) mounted on a 16 mm Cristal balloon (Balt Extrusion, Montmorency, France) was then introduced through the sheath. During the deployment of the stent, the distal end of the balloon opened first deforming the stent into a cone shape. The balloon was partly deflated and repositioned over the incompletely expanded proximal stent. During inflation there was forward migration of the stent with embolization into the atrial chambers, but still contained by the looped guidewire passing through the stent (Figure 2). A surgical opinion was sought and open heart surgery felt to carry a high mortality risk and therefore not a good option. We therefore pursued a catheter based strategy, initially using a 20 mm Amplatzer Gooseneck snare kit passed through the long delivery sheath in an attempt to crimp the stent down onto the balloon. This proved impossible as the snare could not encompass the stent circumferentially. The procedure also resulted in more distal movement of the stent and was therefore abandoned. Next, we inflated a 16 mm Cristal balloon within the stent and captured it and attempted to pull it proximally into the stenosis. Despite hard pulling it was not possible to engage the stenosed coronary sinus ostium. At this stage we considered use of a second stent within the embolized stent to secure the latter in the coronary sinus ostium. We therefore delivered a PG395P Cordis Genesis Palmaz stent (Johnson & Johnson Interventional Systems Co., Warren, New Jersey) mounted on an 18 mm x 4 cm Cristal balloon via 10 Fr Amplatzer ASD delivery sheath. The stent was positioned and deployed with its distal end engaging the proximal one-third of the embolized stent and its proximal end traversed the ostial stenosis (Figure 3). Repeat angiography demonstrated complete resolution of the coronary sinus stenosis and secure capture of the free-floating embolized stent. Immediately following the procedure there was no significant change in ventricular function, but over the ensuing 1 year there seemed to be a gradual improvement in overall function such that the ventricle became moderately dysfunctional. Discussion. Coronary sinus obstruction is a rarely detected clinical problem.1 Though usually congenital, it may be acquired secondary to venous cannulation injury, primary coronary sinus thrombosis, fungal endocarditis, heart transplant and or mitral valve surgery.^2,3 The coronary sinus when obstructed usually has effective drainage via collateral Thabesian veins or via the left superior caval vein into the bridging vein and subsequently into the right superior caval vein in congenital cases of heterotaxy. Rarely, however, superior caval or collateral Thabesian vein run-off is inadequate, impeding antegrade myocardial perfusion and resulting in ventricular dysfunction, pericardial effusion and sudden cardiac death.^4–7 Under these latter circumstances relief of the obstruction has been documented to be beneficial.^5,7 In the case described in this report, the left superior caval vein run-off was occluded, therefore coronary sinus stenting was a reasonable strategy. During stent deployment, the balloon inflated unequally due to differential external compression within the stenosed area as compared with the portion of the balloon protruding unopposed into the atrial chamber. This resulted in forward movement in the direction of least resistance and eventually embolization of the stent. Normally this complication can be dealt with by cessation of inflation as long as there is some degree of stent stability either against the balloon or the stenosed area. The balloon can then be positioned more proximally and re-inflated. This was not successful in our case as the stent had already moved forward to such a degree that proximal re-inflation promoted migration and completed the embolization process. When differential inflation of the balloon is proximal, the sheath can be advanced over the proximal portion of the balloon and during re-inflation only the distal end will expand. Arguably, use of a BIB balloon may have prevented this complication. Inflation of the inner balloon usually results in release of any asymmetric initial opening of the stent during balloon inflation. It is however difficult to know if the external compressive forces in the proximal stenosed coronary sinus may have still resulted in unequal opening of the stent. In our case the generously looped wire within the atrium contained the stent on the guidewire and within the atria allowing us sufficient time to formulate and test different strategies to address the problem. We did not form a veno-arterial loop in this case since the outlet of the ventricle was partly protected by a mechanical valve prosthesis. Though crimping of the stent onto the balloon has been described8 we could not safely circumscribe the stent to allow this to be done. Next, we recaptured the embolized stent on a balloon and attempted to pull this back into the coronary sinus ostium. This too was ineffective due to the balloon being too big in combination with the unfavorable hemispheric profile at the proximal inflated end. We abandoned this strategy as we feared that excessive force would rupture the atrial wall or coronary sinus. In the end we used a telescoping technique, capturing the embolized stent and anchoring it within the stenosed area by means of an interposing 2nd longer stent. This was based on our experience of overlapping stents in long-segment pulmonary arterial stenoses. To our knowledge, this technique has not previously been described in the context of a stent embolized within a chamber. Conclusions. Migration is a well known complication of endovascular stent angioplasty in congenital heart disease occurring in about 3–7.7% cases.^9,10 We believe that use of the telescoping technique when encountering stent embolization into a cardiac chamber may be a useful adjunctive tool to that previously described in the literature.

References

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From the Wessex Congenital Cardiac Centre, Southampton General Hospital, Southampton, United Kingdom. The authors report no conflicts of interest regarding the content herein. Manuscript submitted December 23, 2009, provisional acceptance given January 4, 2010, final version accepted March 1, 2010. Address for correspondence: Dr. Gruschen Veldtman, Consultant Cardiologist, Wessex Congenital Cardiac Centre, Southampton General Hospital, Mail point 46, Southampton, UK SO16 6YD. E-mail: gruschen@aol.com