Percutaneous implantation of pulmonary valves

Factors associated with the internal jugular venous approach for Melody™ Transcatheter Pulmonary Valve implantation

BACKGROUND

Transcatheter pulmonary valve implantation is usually performed from a femoral venous - transfemoral - approach, but this may not be the optimal vascular access option in some patients. This study aimed to determine which group of patients might benefit from an internal jugular - transjugular - approach for transcatheter pulmonary valve implantation.

METHODS

This multicentre retrospective study included all patients who underwent attempted transcatheter pulmonary valve placement in the right ventricular outflow tract between April 2010 and June 2012 at two large congenital heart centres. Patients were divided into two groups based on venous access site - transfemoral or transjugular. Patient characteristics, procedural outcomes, and complications were compared between groups.

RESULTS

Of 81 patients meeting the inclusion criteria (median age 16.4 years), the transjugular approach was used in 14 patients (17%). The transjugular group was younger (median age 11.9 versus 17.3 years), had lower body surface area (mean 1.33 versus 1.61 m2), more often had moderate or greater tricuspid regurgitation (29% versus 7%), and had a higher ratio of right ventricle-to-systemic systolic pressure (mean 82.4 versus 64.7). Patients requiring a transjugular approach after an unsuccessful transfemoral approach had longer fluoroscopic times and procedure duration.

CONCLUSIONS

The transjugular approach for transcatheter pulmonary valve implantation is used infrequently but is more often used in younger and smaller patients. Technical limitations from a transfemoral approach may be anticipated if there is moderate or greater tricuspid regurgitation or higher right ventricular pressures. In these patients, a transjugular approach should be considered early.

Transcatheter mitral valve implantation via transapical approach: an early experience

OBJECTIVES

As many as 50% of patients with severe symptomatic mitral valve regurgitation are denied surgical valve replacement or repair due to high operative risk. We describe an early series of cases of transcatheter implantation with a CardiAQ™ mitral valve via a transapical approach.

METHODS

Three consecutive patients with an Society of Thoracic Surgeons (STS) mortality score of >22% were selected for transcatheter mitral valve implantation (TMVI) on compassionate grounds. All patients were elderly, had severe mitral regurgitation (MR), were in Class IV heart failure and deemed unsuitable for the MitraClip. Two of the patients had functional MR in the setting of ischaemic cardiomyopathy with left ventricular ejection fraction (LVEF) <40%, deemed while the remaining patient had chordal rupture with extensive anterior leaflet flail (preserved LVEF). Comorbidities included previous coronary artery bypass surgery (n = 2), severe pulmonary hypertension (n = 1) and moderate to severe chronic renal failure (n = 3). A CardiAQ mitral valve was implanted using fluoroscopy and transoesophageal (TEE) guidance via a standard transapical approach.

RESULTS

Accurate prosthesis positioning and deployment with immediate elimination of the MR was achieved in all 3 cases. Two patients made full clinical recovery and were discharged home. Post-procedural TEE performed on Days 1, 30 and 60 days showed good valve function, stable valve position and minimal LVOT gradient. One patient expired on the postoperative day 9 due to pneumonia.

CONCLUSIONS

TMVI using the CardiAQ™ device via a transapical approach is feasible and effective.

Bovine valved jugular vein (Contegra™) to reconstruct the right ventricular outflow tract

The right ventricular outflow tract (RVOT) is the part of the circulation located between the right ventricle and the bifurcation of the pulmonary artery. The most cranial part of the right ventriculum infundibulum, the pulmonary anulus, the valve and finally the main trunk of the pulmonary artery are the most important structures. The RVOT is frequently affected in congenital heart diseases, either isolated, or in combination with other cardiac malformations. Current techniques for surgical correction of anomalies of the RVOT include repair and/or replacement of the pulmonary valve often combined with sub- or supravalvular reconstruction. The use of extracardiac conduits (homografts, stented or stentless xenografts) to re-establish continuity between the pulmonary ventricle and pulmonary artery has been an important advance in repair of complex congenital malformations. The Contegra (Medtronic) conduit was introduced as a xenograft tissue for RVOT reconstruction. This conduit has some advantages over homografts including availability for pediatric and adult patient sizes and proximal and distal cuffs allowing for extended reconstruction. The principal late problem related to extracardiac conduit operations is the inevitable need for one or more conduit replacements due to patient somatic growth or progressive conduit degeneration and calcification leading to stenosis.

Percutaneous implantation of the Edwards SAPIEN(™) pulmonic valve: initial results in the first 22 patients

BACKGROUND

Percutaneous pulmonary valve implantation (PPVI) was introduced in 2000 as an interventional procedure for the treatment of right ventricular outflow tract (RVOT) dysfunction. The new Edwards SAPIEN(™) pulmonic valve has reached CE certification at the end of 2010 thus offering an attractive alternative with extended sizes (23 and 26 mm) to the conventional Melody(®) valve (sizes 18, 20 and 22 mm).

PATIENTS

Over a 1-year period, PPVI using the Edwards SAPIEN(™) pulmonic valve was performed in 22 patients using a standardized procedure. Primary diagnosis was tetralogy of Fallot (n = 11), pulmonary atresia (n = 2), Truncus arteriosus (n = 3), TGA/PS-Rastelli (n = 1), Ross surgery (n = 2), double outlet right ventricle (n = 2) and absent pulmonary valve syndrome (n = 1). The character of the RVOT for PPVI was transannular patch (n = 4), bioprosthesis (n = 2), homograft (n = 5) and Contegra(®) conduit (n = 11). The leading hemodynamic problem consisted of a pulmonary stenosis (PS) (n = 2), pulmonary regurgitation (PR) (n = 11) and a combined PS/PR lesion (n = 9).

RESULTS

In 21/22 patients, PPVI was performed successfully (10 × 23 and 11 × 26 mm). There were 9 female and 13 male patients; the mean age was 21.7 years (range 6-83 years), the mean length was 162 cm (range 111-181 cm) and the weight 56.5 kg (range 20-91 kg). Invasive data showed a decrease of RV-systolic pressure from 61.2 mmHg (± 23.1) to 41.2 mmHg (± 8.6) and reduction of RV-PA gradient from 37.3 mmHg (± 23.2) to 6.9 mmHg (± 5.3). The PA-systolic pressure increased from 25.8 mmHg (± 8.6) to 33.9 mmHg (± 9.3) as did the PA diastolic pressure (from 6.0 mmHg (± 5.6) to 14.6 mmHg (± 4.3). There was a substantial reduction of pulmonary regurgitation from before (none/trivial n = 0, mild n = 2, mode rate n = 9, severe n = 11) to after PPVI (none/trivial n = 20, mild n = 1). During the short-term follow-up of 5.7 months there was no change in the immediate results.

CONCLUSION

PPVI using the Edwards SAPIEN(™) pulmonic valve can be performed safely in a wide range of patients with various diagnoses and underlying pathology of the RVOT and enables the restoration of an adult-size RVOT diameter. Although the immediate and short-term results seem promising, the long-term effects and safety have to be assessed in further clinical follow-up studies.

Catheter-based modification of heart valve diseases: from experimental to clinical application

Efforts to modify cardiac valve defects using catheter-based techniques are increasing at the present time. We present observations on cardiac valve morphology and disease and review the progress being made to address valve defects with these innovative methods. Some new procedures developed through animal experimentation have already been put to use in clinical practice, but the newness of these techniques and the small number of cases in which they have been applied to date precludes an evaluation of their long-term durability. Although at the present time cardiac surgery remains the standard for treating most cases of valve disease, in certain situations a catheter-based treatment might provide a reasonable alternative, even if only temporary, especially for individuals with serious disease who are not suitable candidates for surgery.

Right ventricular outflow tract reconstructive model in adult sheep

Patients born with congenital right ventricular outflow tract lesions are faced with invasive procedures to establish hemodynamic and physiological stability. Commonly, multiple subsequent surgical procedures are required due to deterioration of a previous repair. These procedures carry additive risks of mortality and morbidity. Less aggressive procedures with accompanying lower risk is ideal. Success in percutaneously placing a transcatheter valve has previously been reported; however, continued safety and efficacy of any technique needs continual assessment. We developed a model for preclinical evaluation of a percutaneous placement of a pulmonic transcatheter valve in adult sheep, including preoperative, surgical, and postoperative techniques for long-term evaluation. Adult sheep were assessed and determined to be acceptable for study enrollment. Perioperative antibiotics and analgesics were given prior to a left thoracotomy. A Medtronic, Hancock 1 valve conduit was inserted for reconstruction of the right ventricular outflow tract. The Hancock 1 valve conduit alone represented the control group and the test animals comprised the addition of a Melodytrade mark transcatheter pulmonary valve (TPV), within the Hancock 1 valve conduit. Fifteen adult sheep survived the surgical implant procedure with no perioperative mortality. There were four early postoperative deaths, three due to infection and one due to heart failure, secondary to intraoperative heart block. The remaining 11 animals remained healthy, gained weight, and survived to termination at 5 months. An initial definite-sized valve conduit was implanted, followed by inserting a single size TPV, which allowed a more accurate physiological assessment of any chosen valve. Our developed adult sheep model for percutaneous TPV implantation for right ventricular outflow tract lesions was successful for long-term assessment by utilizing our preoperative, surgical, and postoperative techniques.

Percutaneous implantation of the pulmonary and aortic valves: indications and limitations

Percutaneous transcatheter intervention for valvular heart disease is the new horizon in transcatheter therapeutics. Balloon dilatation has been used successfully for treatment of congenital and acquired stenotic lesions of semilunar and atrio-ventricular valves. Although attempts have been made to repair and replace cardiac valves without cardiopulmonary bypass and through percutaneous techniques, this has only recently become a reality. The semilunar valves have preceded atrioventricular valves in successful application in animals and humans. Morphological features play an important role in determining the design of the valve and technique and site of implantation. The major deviations in research and development in artificial or tissue valves have included attempts at delivery of these valves to the site of implantation without open heart surgery. Successful implantation needs long-term follow-up for the durability of the valve and freedom from re-intervention.

Current Experience with Percutaneous Pulmonary Valve Implantation

Transcatheter valve replacement has recently been introduced into clinical practice and has the potential to transform the management of valvular heart disease. To date, the largest human experience exists with percutaneous pulmonary valve implantation in patients with repaired congenital heart disease who require re-intervention to the right ventricular outflow tract. The application of this approach, however, is presently restricted to certain right ventricular outflow tract morphologies, because the device needs to be anchored safely to prevent device dislodgement. Early results of percutaneous pulmonary valve implantation show lower morbidity than surgery and significant early symptomatic improvement. In the future, the challenge will be to extend percutaneous pulmonary valve implantation to all patients with a clinical indication to delay or avoid repeat open-heart surgery.

Advances in Experimental Percutaneous Pulmonary Valve Replacement

BACKGROUND

Percutaneous pulmonary valve implantation is emerging as an alternative and additional option for a successful surgical scheme. To date, these procedures are performed by the balloon-in-balloon technique. The use of self-expanding stents for percutaneous valve replacement is assumed to improve preservation of the valve in its folded condition in the application device and the valve's long-term functioning. Therefore, initial experience with the development of a completely percutaneous transfemoral technique for pulmonary valve implantation using a self-expanding valved stent is described.

METHODS

Bovine jugular xenografts were sutured into nitinol stents, and functional in vitro tests of valved stents were carried out. Transfemoral implantation in pulmonary position was acutely evaluated in 6 sheep weighing 22 to 29 kg. Radiologic evaluation was performed by angiography and multislice computed tomography (MSCT) scan. In addition, pathoanatomical studies were performed.

RESULTS

Exact implantation in pulmonary valve position was achieved in 5 of 6 sheep, with 1 early stent migration. Another sheep died before stent placement owing to perforation of the right ventricle by the delivery system. Orthotopic pulmonary valved stent position was depicted by MSCT in all other sheep (n = 4). The peak-to-peak transvalvular gradient was 8.2 +/- 3.9 mm Hg (n = 5). Postmortem examination revealed intact stent valves with no adherent clots. No macroscopic damage of the pulmonary artery was noted, whereas minor hematoma of the right atrium and the right ventricular outflow tract were observed in 2 hearts.

CONCLUSIONS

This acute study demonstrates that memory nitinol valved stents can be optimally deployed in the pulmonary position through the groin in sheep.

Reduction of QRS duration after pulmonary valve replacement in adult Fallot patients is related to reduction of right ventricular volume

AIMS

Late after total correction, Fallot patients with a long QRS duration are prone to serious arrhythmias and sudden cardiac death. Pulmonary regurgitation is a common cause of right ventricular (RV) failure and QRS lengthening. We studied the effects of pulmonary valve replacement (PVR) on QRS duration and RV volume.

METHODS AND RESULTS

Twenty-six consecutive Fallot patients were evaluated both pre-operatively and 6-12 months post-operatively by cardiac magnetic resonance (CMR). In this study, we present the computer-assisted analysis of the standard 12-lead electrocardiograms closest in time to the CMR studies. For the whole group, QRS duration shortened by 6+/-8 ms, from 151+/-30 to 144+/-29 ms (P=0.002). QRS duration decreased in 18 of 26 patients by 10+/-6 ms, from 152+/-32 to 142+/-31 ms. QRS duration remained constant or increased slightly in eight of 26 patients by 3+/-3 ms, from 148+/-27 to 151+/-25 ms. CMR showed a decrease in RV end-diastolic volume from 305+/-87 to 210+/-62 mL (P=0.000004). QRS duration changes correlated with RV end-diastolic volume changes (r=0.54, P=0.01).

CONCLUSION

Our study shows that PVR reduces QRS duration. The amount of QRS reduction is related to the success of the operation, as expressed by the reduction in RV end-diastolic volume.