Percutaneous intervention for central shunts: new routes, new strategies.

Introduction In traditional locations, the standard Blalock-Taussig shunt presents numerous technical difficulties for percutaneous intervention. We changed our strategy to a central type shunt (Laks-type) with end-to-side pulmonary and side-to-side aortic anastomosis. The aim of this study was to determine whether this modified strategy would allow easier percutaneous manipulation in patients with small pulmonary arteries. Methods All children with a stretchable central vascular graft who required any form of percutaneous intervention were prospectively enrolled in the study. Results Eleven infants were evaluated a median time of 3 months (range 0.9-4.4) following initial shunt placement; the median weight at intervention was 5.7 kg (range: 4.0 - 10.0). All shunts (100%) were easily and swiftly entered without the need for special catheters or co-axial systems. In four patients other interventions in distal pulmonary arteries were first performed: cutting balloon treatment in three and balloon angioplasty of peripheral pulmonary artery stenosis in one. The shunts were then augmented with a stent with a diameter increasing from 3.5 ± 0.4 mm to 4.7 ± 0.8 mm and saturation increasing from 76% (range: 69-88) to 84% (range: 77-88) (P < 0.05). Several months later, two children required further interventions that could easily be performed via the stented shunts. No complications were observed. Conclusions The Laks-type shunt provides easy access for percutaneous procedures of the distal pulmonary arteries including cutting balloons; this shunt can predictably be expanded to augment pulmonary flow. This study highlights how co-operation between the interventionalist and the surgeon can improve strategies to manage these difficult patients.

Can a volume challenge pinpoint the limiting factor in a Fontan circulation?

OBJECTIVE: It is difficult to indicate whether the limitation in a failing Fontan circulation lies within the pulmonary vasculature or the heart. Such differentiation is crucial to direct adequate therapy. This study was set out to determine if a volume challenge could identify the limiting factor. METHODS AND STUDY POPULATION: Thirty-two catheterizations in 28 patients with a Fontan circulation were included. Pressures and oxygen saturations were measured before and after volume challenge (NaCl 0.9%; 15 cc/Kg). The changes in data were grouped based on the location of the major pressure increase. Ventricular function was measured in the resting state. RESULTS: The majority of the patients showed an increase in aortic oxygen saturation, mixed venous oxygen saturation, systolic, pulmonary and systemic venous pressures. The arterio-venous oxygen gradient decreased, suggesting an increase in cardiac output. Different patterns in pressure changes were observed. Most (n=17) showed a similar increase of ventricular end-diastolic pressure and mean venous pressure (MVP); some (n=7) showed a lower increase of MVP, suggesting pulmonary reserve and recruitment; others (n=8) showed a significant higher increase in MVP, suggesting increased pulmonary vascular resistance. All volume challenge was well tolerated. CONCLUSION: Most patients were preload-responsive. The pressure changes following volume load showed patterns with a potential of differentiating between patients with a major pulmonary or cardiac limiting factor.

Percutaneous pulmonary valve implantation for free pulmonary regurgitation following conduit-free surgery of the right ventricular outflow tract.

INTRODUCTION: Pulmonary regurgitation (PR) following surgery of the right ventricular outflow tract (RVOT) is not innocent and leads to significant right heart dysfunction over time. Recent studies have demonstrated that percutaneous valves can be implanted in conduit free outflow tracts with good outcomes. OBJECTIVES: To evaluate in patients with severe PR--anticipated to require future pulmonary valve replacement--the feasibility and safety of pre-stenting dilated non-stenotic patched conduit-free right ventricular outflow tracts before excessive dilation occurs, followed by percutaneous pulmonary valve implantation (PPVI). PATIENTS AND METHODS: Twenty seven patients were evaluated, but only 23 were deemed suitable based on the presence of an adequate retention zone ≤ 24 mm defined by semi-compliant balloon interrogation of the RVOT. A 2 step procedure was performed: first the landing zone was prepared by deploying a bare stent, followed 2 months later by valve implantation. RESULTS: RVOT pre-stenting with an open cell bare metal stent (Andrastent XXL range) was performed at a median age of 13.0 years (range: 6.0-44.9) with a median weight of 44.3 kg (range: 20.0-88.0). Ninety six percent (22/23) of patients proceeded to PPVI a median of 2.4 months (range: 1.4-3.4) after initial pre-stent placement. Twenty one Melody valves and one 26 mm Edwards SAPIEN™ valve were implanted. Complications consisted of embolization of prestent (n = 1), scrunching (n = 4) and mild stent dislocation (n = 2). During follow-up, no stent fractures were observed and right ventricular dimensions decreased significantly. CONCLUSIONS: Post-surgical conduit-free non-stenotic RVOT with free pulmonary regurgitation can be treated percutaneously with a valved stent if anatomical (predominantly size) criteria are met. In experienced hands, the technique is feasible with low morbidity.

Infective endocarditis of a transcatheter pulmonary valve in comparison with surgical implants.

BACKGROUND: Melody valved stents (Medtronic Inc, Minneapolis, Minnesota, USA) have become a very competitive therapeutic option for pulmonary valve replacement in patients with congenital heart disease. After adequate prestenting of the right ventricular outflow tract (RVOT) Melody valved stents have a good medium term functional result but are exposed to infective endocarditis (IE). PATIENTS AND METHODS: Retrospective study of tertiary centre Congenital Heart Disease database; to compare incidence of IE in three different types of valved conduits in RVOT: Melody valved stent, cryopreserved homograft (European Homograft Bank) and Contegra graft (Medtronic Inc). RESULTS: Between 1989 and 2013, 738 conduits were implanted in 677 patients. 107 Melody valved stents were implanted in 107 patients; IE occurred in 8 (7.5%) patients during a follow-up of 2.0 years (IQR 2.4 years, range 0.3-7.8 years). 577 Homografts were implanted in 517 patients; IE occurred in 14 patients (2.4%) during a median follow-up of 6.5 years (IQR 9.2 years; range 0.1-23.7 years). Finally, 54 Contegra grafts were implanted in 53 patients; 11 patients (20.4%) had IE during a follow-up of 8.8 years (IQR 7.7 years; range 0.2-3.5 years). Survival free of IE by Kaplan-Meier for homografts was 98.7% at 5 years and 97.3% at 10 years; for Contegra 87.8% at 5 years and 77.3% at 10 years and for Melody 84.9% at 5 years (log-rank test; p<0.001). CONCLUSIONS: The Contegra conduit and Melody valved stents have a significantly higher incidence of IE than homografts. IE is a significant threat for long-term conduit function.

Use of covered Cheatham-Platinum stents in congenital heart disease.

BACKGROUND: Controversy remains regarding the use of covered stents in congenital heart disease (CHD). We evaluate the possibilities and safety of covered Cheatham-Platinum (CCP) stents in CHD. METHODS: Single-center retrospective CHD-database study of all CCP stents, 2003-2012. Three study groups: aortic coarctation (CoA), right ventricular outflow tract pre-stenting for percutaneous revalvulation (RVOT), and miscellaneous. Continuous data expressed as median (range). RESULTS: 114 CCP stents in 105 patients, age 16.8 years (4.2-71.2). CoA group: 54 CCP stents in 51 patients: 3/54 for aneurysm exclusion, in 51/54 covering used "prophylactically" because of increased risk for vessel tear. Overall, CCP stenting increased the coarctation diameter from 6mm (0-15) to 15 mm (10-20) (p<0.001). RVOT group: 39 CCP stents in 37 patients (34 with RVOT graft, 3 with transannular patch): the graft lumen had shrunken from nominal 21 mm (10-26) to 13 mm (5-22); with the CCP stent the RVOT was redilated to 22 mm (16-26, p<0.001 vs stenosis). Miscellaneous group: 21 CCP stents in 17 patients: closure of Fontan-circuit fenestration (n=5), restoration of superior caval vein (n=2) or pulmonary artery (n=3) patency, relief of supra-pulmonary stenosis (n=2), exclusion of aberrant pulmonary arteries (n=1), cavopulmonary conduit expansion (n=2), Blalock-Taussig shunt flow reduction (n=1), and defibrillator lead protection from sharp stents (n=1). Hybrid procedures performed in 3/17 patients. CCP stent was used as rescue treatment in 2/patients to seal iatrogenic bleeding. CONCLUSION: CCP stents can safely be applied in CHD patients. The covering allows adequate sealing of existing or expected tears, thereby increasing the safety margin with more complete dilation.

Delivering stents in congenital heart disease using the double-wire technique: technical considerations.

OBJECTIVES: To evaluate the use of a double-wire technique to deliver stents. BACKGROUND: Placement of a stent in lesions close to bifurcations or without an anatomic obstruction can be problematic. PATIENTS AND METHODS: Stents were implanted in 12 patients between August 2010 and August 2012. Indications were complex anatomic obstruction in nine, external compression of pulmonary veins in two, and exclusion of an aortic aneurysm in one patient. RESULTS: Median age and body weight of the group were 11.6 years (range: 1.6-34.8) and 36 kg (range: 10-78), respectively. All stents were delivered safely and the patency of all side vessels was maintained; the distal end of the stent was flared to a median ratio of 1.4 (range: 1.2-1.8). The clinical objective was met in all patients: in lesions with stenosis, diameter increased from 5.9 mm (range: 1-13) to 9.9 mm (range: 8-17) [P < 0.01; 95% confidence interval (CI): 2.0-7.2]; oxygen saturations improved in the 2 patients after relief of the external pulmonary venous compression and in another an aortic aneurysm was excluded. One patient developed a hemothorax and one required blood transfusion for bleeding from the valve of the sheath. CONCLUSIONS: The double-wire stenting technique is effective to accurately deliver and anchor stents into lesions close to side branches and bifurcations. Side branch patency is maintained; the clinical objective (gradient relief, aneurysm exclusion, relief of external compression) can safely be reached. Technique and balloon selection should be based on the underlying anatomical substrate.

Off-label use of percutaneous pulmonary valved stents in the right ventricular outflow tract: time to rewrite the label?

INTRODUCTION: Percutaneous pulmonary valve implantation is now considered feasible and safe. "Native" right ventricular outflow tract (RVOT), small diameter conduits (<16 mm) and relatively large RVOT with a dynamic outflow aneurysm are currently considered off-label uses. Extending indications creates concerns of safety, ethics, reimbursement, and liability. AIM OF STUDY: To report the safety and feasibility of off-label application of percutaneous pulmonary valve implantation. DESIGN: Retrospective analysis of prospectively collected data. PATIENTS AND METHODS: Off-label indications: conduit-free RVOT or patients with an existing but undersized conduit. RESULTS: Twenty-one Melody® valves and two Sapien® valves were successfully implanted in 23 patients (16.9 years; range 6.1-80.5 years). In 22 patients, prestenting was performed 4.8 months (range 0-69.2) before valve implantation (15 covered and 13 bare stents). Stent endothelial ingrowth was allowed for at least 2 months prior to implantation of the percutaneous valve if stent stability or sealing by the covering was presumed to be insufficient. Group 1 patients (n = 8) had a "conduit-free" RVOT after transannular/infundibular patch and after prestenting underwent percutaneous pulmonary valve implantation (PPVI), with a final RVOT diameter of 21.5 mm (range 16-26 mm). Group 2 patients consisted of two elderly patients with pulmonary valve stenosis and severe RVOT calcifications. Group 3 (n = 13) had an existing conduit (nominal 15.9 ± 3.2 mm; range 10-20 mm). The conduit was augmented from 14.7 ± 3.5 to 20 ± 1.6 mm with PPVI. The RVOT preparation and valve implantations were uneventful. CONCLUSIONS: PPVI is safe and feasible in selected patients with an off-label indication. Creating an adequate "landing zone" by prestenting makes the procedure safe and predictable. Updating the indications for PPVI should be considered.

Bailout stenting for critical coarctation in premature/critical/complex/early recoarcted neonates.

BACKGROUND: Surgical repair of critical coarctation can be problematic in premature, critical, complex, or early postoperative neonates. OBJECTIVES: We aimed to review our experience with stent implantation to defer urgent surgery to an elective time. METHODS: Fifteen neonates with severe aortic coarctation: five premature-hypotrophic (1,400-2,000 g), six critical and complex cardiac malformation, four early (1 day [0-2 days]; median [range]) after surgical coarctectomy or complex arch reconstruction. Bare coronary stents (diameter 4.0 [3.5-5.0] mm; length 10 [8-16] mm) were used. Stents were removed surgically depending on clinical needs. RESULTS: Adequate aortic flow was obtained in 15 patients. The femoral artery was preserved in 13/15 patients. Two deaths occurred before stent removal and were nonprocedure related. In patients with simple stented coarctation, the stent was removed after 2.8 [0.2-5.0] months. In complex cardiac malformation, stents were finally removed 3.0 [0.2-78] months after implantation. SURGICAL TECHNIQUE: simple coarctectomy end-to-end in eight, extensive arch patch reconstruction in four. One patient is awaiting stent removal. The final maximum systolic velocity (cw-Doppler) across the aortic arch was 1.7 [1.2-2.5] m/sec. CONCLUSIONS: In premature/critical/complex neonates with severe coarctation, bailout stenting followed by early or late surgical coarctectomy appears a promising concept.

Stent expansion of stretch Gore-Tex grafts in children with congenital heart lesions.

OBJECTIVE: To evaluate the efficacy and safety of expanding vascular shunt grafts beyond original nominal diameter using stents. METHODS: Bench testing confirmed the expandability of 3.5 mm and 4.0 mm vascular Gore-Tex stretch grafts. A retrospective analysis included eleven systemic to pulmonary artery shunts with diminished flow which were stented with the aim of increasing the original nominal diameter of the shunts. RESULTS: During bench testing, the grafts could be expanded to 4.5 mm and 5.8 mm, respectively. Fourteen stents were implanted in 11 stretch grafts a median of 18.9 months (3.2; 21.6 months) after shunt surgery. There was a median increase in diameter of 1.4 mm (0.9; 1.7 mm) [P = 0.001, 95% CI: 0.47; 1.7) from original nominal to final stented diameter of the shunts with a median gain of 28%. A simultaneous improvement in saturations from a median of 73% (66; 77%) to 87% (84; 89%) [P = 0.015; 95% CI: 3; 22] was observed. No complications were experienced during the procedures. CONCLUSION: In our limited experience, stretch Gore-Tex vascular grafts can be safely expanded beyond nominal diameters using high pressure vascular stents. This leads to improvement in saturation and pulmonary blood flow. It allows the clinician to tailor pulmonary flow in relation to pulmonary artery size and growth, ensuring best possible timing for the next surgical procedure.

Sutureless rescue of a severely hypoplastic pulmonary artery.

The management of severely hypoplastic pulmonary arteries in the adolescent or adult with congenital heart disease is challenging. A patient with pulmonary atresia and ventricular septal defect (PA-VSD) presented with severe cyanosis due to a kinked and thrombosed right ventricle to pulmonary artery conduit. Retrograde wedge angiography showed a patent right and a diminutive left pulmonary artery deep in the lung hilus. Treatment options were limited and therefore a different strategy had to be considered to rescue the lung segments. This case report describes the novel use of a covered stent to successfully obtain a sutureless connection between a vascular graft and a diminutive pulmonary artery during a hybrid procedure.

Percutaneous management of a Fontan fenestration: in search for the ideal restriction-occlusion device.

OBJECTIVE: Most devices devices available for percutaneous closure of Fontan fenestrations tend to be bulky. The aim of this study was to evaluate a low profile custom made device and assess its efficacy and safety. PATIENTS AND METHODS: A 15 mm PFO star was used as the basis. The following modifications were made: removal of the left disc to reduce thrombogenicity in the left atrium, increase the length of the LA legs from 2 by 15 mm to 3 by 20 mm to prevent dislodgement and later adding a pivot between the left and right umbrella. A partial occluder was made by removing two opposite quadrants from the proximal disk. RESULTS: Device deployment was possible in 93% (63 of 68) patients. In five patients, the device could not be deployed and an alternative device was used. In 45 patients complete closure of the fenestration was obtained and saturations increased from 84% +/- 4% to 95% +/- 2% (P < 001). In 18 high risk patients with suboptimal Fontan circulation, a modified device was used to effect partial occlusion: saturations increased from 79% +/- 7% to 90% +/- 4% (P < 0.001); a residual shunt persisted in most patients for several months. No thrombotic events were recorded during follow-up. CONCLUSIONS: The modified PFO star device can safely be deployed in Fontan patients to occlude or restrict flow through a fenestration. It has a low profile with minimal foreign material, is non-obstructive and minimally thrombogenic.

Volume load paradox while preparing for the Fontan: not too much for the ventricle, not too little for the lungs.

Ventricular dysfunction is frequently encountered in Fontan patients. Cardiologists and cardiac surgeons have, therefore, mainly focused on preservation of cardiac function, limiting the early volume overload as much as possible both in magnitude and duration. This resulted in improved cardiac function but, in some patients, also in poor pulmonary artery (PA) growth which in turn resulted in a poor final Fontan circuit. The volume requirements for optimal growth and development of the ventricle and the lungs are different and divergent. Avoiding overload of the ventricle is important, but excessive protection from volume overload may not be necessary and may result in PA hypoplasia, which in turn will severely affect the Fontan circuit.

Use of a microcatheter in a telescopic system to reach difficult targets in complex congenital heart disease.

BACKGROUND: Some lesions can be very difficult to reach, especially if acute angles and/or multiple turns "protect" access. Once reached, the guiding system needs to give sufficient support for balloons or stents to be deployed. METHODS: A "telescopic" system was created consisting of: (1) a microcatheter with guidewire. This system fits into any catheter allowing a 0.035 inch wire. (2) a 4Fr "delivery" catheter. (3) If sharp angles were encountered, the 4Fr catheter was deployed through a 6Fr or larger angulated guiding sheath. This was cut-off 15 cm out of the groin and re-valvulated with a standard short introducer sheath. PATIENTS AND RESULTS: Since 2004, 89 microcatheter telescopic systems were used during a 4-year period in 1,225 procedures (7.3%). The technique allowed probing with a floppy steerable and exchangeable guidewire, securing any gained position as well as exchanges with a stiffer guide wire if required. Procedures where the telescopic system was effective included: complex stenoses e.g. aortopulmonary collaterals (n = 21), tortuous ducts (n = 9), anterograde balloon dilation of critical aortic stenosis (n = 8) and crossing Blalock Taussig shunts (n = 3). Once in place, the telescopic system allowed delivery of embolic material (n = 38), balloon angioplasty (n = 21), stent deployment (n = 23), fulguration of pulmonary valve (n = 1) or introduction of medication (n = 1). The interventionalists felt that using the telescopic system had reduced fluoroscopy and procedure time. CONCLUSIONS: The microcatheter-telescopic system is an invaluable tool to reach difficult targets and allows exchange for suitable guidewires permitting balloons, stents, embolisation material or radiofrequency energy to be deployed in such targets. This approach has become our standard when dealing with difficult targets protected by a tortuous route.

Stenting the neonatal arterial duct.

Ductal stenting in neonates with either duct-dependent pulmonary or systemic circulation has become a good alternative for the initial palliation of complex congenital heart disease. Changes of stent and catheter technology (low profile, flexible, premounted stents with good scaffolding), better patient selection and preparation, optimal interventional access and covering the complete length of the duct have significantly improved results.

Late redilation of a stent in the aorta crossing the subclavian artery complicated with a cerebellar infarction.

Redilation of a stent appears a simple and safe procedure but complications do occur. A case is reported where redilation of a stent in the aorta crossing the subclavian artery was complicated by embolisation of neo-endothelium or peel into the vertebral artery, causing a cerebellar infarction.

Stenting the neonatal arterial duct in duct-dependent pulmonary circulation: new techniques, better results.

OBJECTIVES: The goal of this study was to assess a new approach to stent the arterial duct in neonates with a duct-dependent pulmonary circulation. BACKGROUND: Previous attempts to stent the neonatal arterial duct were unsatisfactory. Learning from these failures, we speculated that covering the complete length of the duct with current low-profile stents might avoid previous problems. METHODS: Ten neonates with duct-dependent pulmonary circulations through a short straight duct were treated with stent implantation. The duct was crossed with an atraumatic 0.014-inch wire. A low-profile premounted coronary stent (outer diameter <4F, length 13 to 24 mm, diameter 3.0 to 4.0 mm) was positioned within the duct, not protected by a sheath; care was taken to cover the complete length of the duct from the aortaductal junction until well within the pulmonary trunk. RESULTS: All stents could safely be deployed with adequate pulmonary flow at early- and medium-term follow-up. There were no procedure-related complications; one patient died early from sepsis. All patients had adequate relief of cyanosis for at least three to four months. During follow-up, the pulmonary vasculature bed had grown without distortion. Acute occlusion of a stented duct was not observed. Ductal flow progressively decreased slowly over several months by luminal narrowing, until the stented duct had either become redundant or was dilated/restented or until elective staged surgery was performed. CONCLUSIONS: With current technology, complete stenting of a short straight duct is a safe and effective palliation, allowing adequate growth of the pulmonary arteries.