In vitro study of coronary flow occlusion in transcatheter aortic valve implantation.

BACKGROUND: Transcatheter aortic valve implantation (TAVI) has been developed recently for patients with high morbidities and who are believed to be not tolerate standard surgical aortic valve replacement. Nevertheless, the TAVI is associated with complications such as potential obstruction of coronary ostia, mitral valve insufficiency, and stent migration although it seems promising. Impairment of the coronary blood flow after TAVI is catastrophic and it was believed to be associated with the close position of the coronary orifice and the aortic leaflets and valve stent. However, few data was available as to the anatomic relationship between valve stent and aortic root anatomic structures including the coronary arterial ostia, aortic leaflets. METHODS: The aortic roots were observed in 40 hearts specimens. The width of aortic leaflet, height of aortic sinus annulus to the sinutubular junction (STJ), distance between aortic sinus annulus to its corresponding coronary ostia, and coronary arterial ostia to its corresponding STJ level were measured. Moreover, the relationships of valve stent, aortic leaflets and coronary ostia before/post stent implantation and after the open of aorta were evaluated respectively. RESULTS: Approximate three quarters of the coronary ostia were located below the STJ level. The mean distances from left, right and posterior aortic sinus annulus to the related STJ level was comparable, which was 18.5±2.7, 18.9±2.6, 18.7±2.6 mm, respectively. Meanwhile, the height of left and right aortic sinus annulus to its corresponding coronary ostia was 16.6±2.8 and 17.2±3.1 mm for left and right side respectively. CONCLUSIONS: Most of the coronary ostia were located below the STJ level and could be covered by the leaflets. This highlights the need of modified stents to prevent occlusion of coronary flow after TAVI.

Transcatheter valve implantation: damage to the human aorta after valved stent delivery system exposure--an in vitro study.

Transcatheter heart valve implantation can be performed transapically and transfemorally. The transfemoral way to the aortic valve is significantly longer than the transapical one. The aim of this study was to analyse the intima of 15 human aortas after the deployment of different conventional valved stent delivery systems. Fifteen human aortas have been analysed (77 ± 8.4 years). These aortas were preserved with formalin and explanted from the common iliac arteries to the ascending aorta. After protocolling all relevant vascular parameters, the deployment force of different conventional valved stent delivery systems was analysed. After that, the intima was closely investigated by endoscopy. The deployment force of the old catheter was not different from the actual system. The endoscopic investigation revealed significant intimal damages in all parts of the aorta after deployment of the delivery system. This study demonstrated that the passage to the aortic valve can result in significant intimal damage regardless of the used deployment catheter. Efforts are necessary to lower the profile of the deployment devices to increase their flexibility. The intima of the aorta and possible damage have to get back into the physicians' focus to avoid possible late aortic complications.

Transcatheter aortic valve replacement: transapical resection of the aortic valve in vivo.

The resection of pulmonary valves has already been demonstrated in an experimental beating-heart model. The aim of this study was to analyse the transapical laser-assisted resection of aortic valves in an in vivo porcine model in a non-beating heart. The resection was performed in a porcine model (n = 10) using a Thullium:YAG laser. After establishing a standard extracorporeal circulatory support, the aortic valve isolation chamber (AVIC) system was inserted transapically. The resection of the aortic leaflets was carried out step-by-step in the arrested heart. The AVIC implantation, the resection process, and the gross anatomy of intracardiac lesions were analysed. The procedure for installing the AVIC took 5.8 ± 1.5 min. A sealed chamber was achieved in 9/10 cases. The resection of the valves was performed in 8/10 and completed in 7/10 cases. The resection took, on average, 7.4 ± 2.7 min/cusp. In 9/10 cases, the sealing was sufficient. Gross anatomy and histological analysis demonstrated only superficial damage to the surrounding tissue. In this study, the in vivo on-pump isolation of the left ventricular outflow tract and the laser resection of the native aortic valve could be demonstrated successfully. Nevertheless, this model is the next step towards a beating-heart resection of the aortic valve using the isolation chamber.

Professional parachuting: the risk of acute aortic dissection.

Acute aortic dissection is a rare disease, but if it occurs rapid diagnosis and therapy are needed. It is usually seen in elderly patients with long-term persistent arterial hypertension. In younger patients, it is mainly caused by congenital connective tissue disorders, such as Marfan syndrome, or by trauma. We present here a 34-year-old male patient with an acute type A aortic dissection. This patient was a professional parachutist and had carried out a large number of parachute jumps during his lifetime. He was admitted to the emergency department with acute chest pain. The symptoms were not related in time to a parachute jump. During a computed tomography scan, an aortic dissection was diagnosed. The patient was immediately referred to the operating room, and the ascending aorta was replaced by a conduit. After a regular postoperative course, the patient was discharged and recovered completely. Although acute aortic dissection is rare in young patients, it has to be considered in cases of acute chest pain. An immediate diagnosis and adequate therapy are essential to offer the patient a good clinical outcome and long-term survival.

Percutaneous aortic valve replacement: valvuloplasty studies in vitro.

OBJECTIVE: Valvuloplasty of the aortic valve is currently used in selected patients for severe calcified aortic valve disease, but clinical effectiveness is low and complication rate remains high. In this study, the total particle load after valvuloplasty and the embolization risk of calcific debris into the coronary arteries was analyzed in an in vitro model. METHODS: Three highly calcified human aortic leaflets have been sutured into a porcine annulus (N = 9). Both coronary arteries were separated and each was anastomized to a silicon line, which was drained off into a measuring beaker. Then valvuloplasty was performed (Thyshak II, 20 mm, 1.5 atm). After removal of the balloon, 100ml of sodium chloride solution irrigated the ascending aorta. After passing through the separated coronary arteries, the solution was filtered (filter size 0.45 µm), dried, and the total amount of particles was analyzed microscopically. RESULTS: Nine experiments were analyzed. After valvuloplasty, all hearts showed a median of 18 particles larger than 1mm in the coronary arteries (range 0-307). The amount of particles smaller than 1mm was 6574 (median, range 2207-14200). In five cases, coronary arteries were completely occluded by bulky particles. CONCLUSION: This study demonstrated a large amount of calcific particles after valvuloplasty with a consequently high risk for coronary embolic events in case of highly calcified aortic valves. In times of valvuloplasty rediscovering as part of transcatheter valve implantation, the risk of embolization should be taken into consideration and filtering techniques have to be developed.

Mitral valved stent implantation.

OBJECTIVE: To date, transfemoral and trans-apical valved stent implantation techniques are limited to the replacement of pulmonary and aortic valves in a strictly selected group of patients. The current study was designed to assess the short-term follow-up using a mitral valved stent in off-pump technique. METHODS: A self-expanding, repositionable mitral valved stent was created for trans-apical implantation. Five pigs underwent successful trans-catheter implantation. Data were gathered to assess the animals' haemodynamical stability after stent implantation (n=5), 6h (n=5) and 1 week (n=4). The valved stent function was assessed by trans-oesophageal echocardiography and ventriculogram. Cardiac computed tomography (CT) was used to evaluate positioning of the new implant. RESULTS: Precise valved stent deployment and accurate subsequent adjustment of its intra-annular position allowed for reduction of paravalvular leakage in all animals. The deployment time ranged from 122 to 271 s and blood loss from 65 to 245 cc. Accurate positioning was established in all but one animal. The average mean transvalvular gradient and mean gradient across left ventricular outflow tract (LVOT) recorded immediately after deployment, 6 h and 1 week were 1.9 + or - 0.9 mmHg, 3.5 + or - 1.6 mmHg, 4.1 + or - 02.3 mmHg and 1.4 + or - 01.3 mmHg, 1.5 + or - 0.7 mmHg 1.9 + or - 0.7 mmHg, respectively. Mild regurgitation was present after valved stent deployment in one out of five animals after 1h, one out of five animals at 6h, and two out of four animals at 1 week. All animals exhibited normal haemodynamics after mitral valved stent implantation and maintained stability for the period of monitoring (6h). One animal died of unrecognised imperfect valved stent positioning after 1 day. In the subsequent animals, valved stent migration, embolisation, systolic anterior movement or LVOT obstruction was not observed after 1 week follow-up. CONCLUSIONS: The new mitral valved stent can be deployed in a reproducible manner to achieve reliable stent stability, minimal gradients across the LVOT and adequate valved stent function in short-term follow-up.

Does patient-prosthesis mismatch influence the results of combined aortic valve replacement and coronary bypass grafting?

BACKGROUND: Combined aortic valve replacement and coronary revascularisation is becoming more frequent. Patient-prosthesis mismatch (PPM) as an additional risk factor may potentially affect the early and late outcome. AIM: To evaluate the impact of PPM on early and mid-term clinical results including quality of life in patients undergoing combined surgical treatment of coronary artery disease and aortic valve defects. METHODS: Medical records of 309 consecutive patients referred for combined surgery were reviewed. Patients were divided into three groups according to the presence of moderate or severe PPM (defined by aortic valve effective orifice area index in the range 0.85-0.65 cm2/m2 and smaller than 0.65 cm2/m2, respectively) or absence of PPM. The demographic and perioperative data, and early and late survival, as well as quality of life (SF-36) were analysed. RESULTS: The presence of severe PPM was found in 51 (16.5%) patients, whereas moderate PPM--in 153 (49.5%) patients. Patients from both PPM groups were significantly older than those without PPM. Subjects with severe PPM had higher weight and body mass index. They frequently had dyslipidaemia and both PPM groups received a biological valve more often than patients without PPM (94.1 and 77.1 vs. 19.1%, p<0.0001). There was no significant difference between all groups regarding early or late mortality. Advanced age, renal insufficiency and arrhythmia were predictors of early death. Late survival was determined only by number of postoperative complications in a Cox regression model. There was no difference in any components of the SF-36 survey between all groups. CONCLUSIONS: PPM is a frequent phenomenon in older patients requiring aortic valve replacement and revascularisation. Severe PPM occurs rarely, predominantly in obese patients. However, its presence does not affect early and late survival or quality of life.

Off-pump transapical mitral valve replacement.

OBJECTIVE: Percutaneous valve replacement was recently introduced, and reports of early clinical experience have already been published. To date, this technique is limited to the replacement of pulmonary and aortic valves in a strictly selected group of patients. The aim of this study was to analyse a self-expanding valved stent for minimally invasive replacement of the mitral valve in animals. METHODS: A newly designed nitinol stent was specially designed for this experimental acute study. It comprised of a left ventricular tubular stent with star shaped left atrial anchoring springs and carried a trileaflet bovine pericardial valve. A polytetrafluoroethylene membrane was sutured to envelop the atrial springs and the outside of the ventricular stent. The ventricular anchoring system was the same as in our previously reported results with a similar mitral valved stent. Seven pigs underwent minimally invasive off-pump mitral valved stent implantation. This was performed through a lower mini-sternotomy and a standard transapical approach under transoesophageal echocardiographic (TEE) guidance was used. RESULTS: The valved stent is fully retrievable and precise deployment and accurate adjustment of its intra-annular position is achievable to eliminate paravalvular leakage. The deployment time ranged from 127 to 255s and the blood loss from 70 to 220cc. One animal died of intractable ventricular fibrillation. Mitral regurgitation in all surviving animals was minimal (trace in 5/6 and mild in 1/6 during echo examination; on the contrast ventriculogram no mitral insufficiency was observed except in one documented as mild paravalvular regurgitation). These animals remained haemodynamically stable (6/6) and without TEE or ventriculographic changes for 1h. CONCLUSION: Implantation of a tricuspid bovine pericardial valved stent in the mitral position is feasible in pigs through a transcatheter approach. This was possible through a smaller delivery system than previously reported. Additional studies are required to demonstrate long-term feasibility, durability, and heart function.

Influence of increased intra-abdominal pressure on fluid responsiveness predicted by pulse pressure variation and stroke volume variation in a porcine model.

OBJECTIVE: Dynamic variables of fluid responsiveness such as pulse pressure variation (PPV) and stroke volume variation (SVV) have been shown to reliably predict the response to fluid administration in different patient populations. The influence of increased intra-abdominal pressure (IAP) on the predictive ability of these variables is currently under debate. Therefore, the present study was designed to evaluate whether PPV and SVV are suitable for predicting fluid responsiveness during elevated IAP. DESIGN: Prospective controlled experimental study. SETTING: Animal research laboratory. SUBJECTS: 14 anesthetized and mechanically ventilated pigs. INTERVENTIONS: Pigs were studied at different experimental stages: normovolemia at baseline conditions, after induction of pneumoperitoneum (PP) by increasing IAP up to 25 mm Hg, followed by releasing PP and performing a fluid load with 1000 cc hydroxyl-ethyl starch 6%, and finally after inducing PP again. Cardiac output, stroke volume, central venous pressure, and pulmonary artery occlusion pressure were obtained by pulmonary artery thermodilution. Additionally, global end-diastolic volume (GEDV) was measured by transpulmonary thermodilution. PPV and SVV were monitored continuously by pulse contour analysis. MEASUREMENTS AND MAIN RESULTS: PP induced significant changes in peak airway pressure, esophageal pressure, chest wall compliance, SVV, PPV, central venous pressure, and pulmonary artery occlusion pressure independent of loading conditions. As assessed by receiver operating characteristic curve analysis, PPV, SVV, and GEDV accurately predicted fluid responsiveness before IAP was increased (area under the curve: 0.90, 0.91 and 0.91). A PPV value of >or=11.5%, a SVV value of >or=9.5%, and a GEDV value of or=15%. After increasing IAP, the ability of SVV to predict fluid responsiveness was abolished, whereas it was preserved with both PPV and GEDV, although the threshold value for PPV dramatically increased up to >or=20.5%. CONCLUSIONS: : In this animal model PPV and GEDV proved to be sensitive and specific predictors of fluid responsiveness even during increased IAP.

Transapical mitral valved stent implantation.

BACKGROUND: Transcatheter aortic and pulmonary valve replacement is currently being tested in human trials. Efforts to create a valved stent to replace the atrioventricular valves have shown limited success. This is due to their their complex anatomy and function. METHODS: A self-expanding valved stent was created for transapical replacement of the atrioventricular valve. Ten pigs underwent transapical off-pump mitral valved stent implantation. Data were gathered to assess the animals' hemodynamic stability for 60 minutes after implantation. The valved stent function was assessed by transesophageal echocardiography (TEE) and contrast left ventriculogram. RESULTS: All animals exhibited normal hemodynamics immediately after mitral valved stent implantation and maintained stability for the entire period of monitoring. Accurate positioning of the valved stent was established in all animals. Mild paravalvular regurgitation was found in three out of ten animals by TEE and in two animals during left ventriculogram. No left ventricular outflow tract obstruction was encountered. CONCLUSIONS: Transapical off-pump mitral valved stent implantation is feasible in an acute experimental setting. Long-term function of the new valved stent remains to be established.

Percutaneous aortic valve replacement: endovascular resection of human aortic valves in situ.

OBJECTIVE: Transluminal in vitro resection of severely calcified human aortic valves has already been successfully carried out by our group. The aim of this study was to analyze endovascular laser-assisted resection of human aortic valves in situ in 10 human cadavers. MATERIAL AND METHODS: After anterolateral minithoracotomy, the aortic valve isolation chamber system was inserted into the descending aorta and pushed forward transluminally into the aortic position to generate a separate operation space between the subvalvular and the proximal ascending aortic area. After deployment and sealing of the chamber, stable function with a continuous chamber lavage of 1.58 L/min saline solution was established (8/10 cases). The endoscopically guided laser fiber was delivered via the right carotid artery. After fixation of a leaflet by a forceps catheter, the native leaflets were resected each by a thulium:YAG laser with 20-W power rating. Macropathology and micropathology of surrounding anatomic structures were analyzed. RESULTS: The duration of transluminal positioning and deployment of the aortic valve isolation chamber took 7.3 +/- 5.8 minutes. Fluoroscopy confirmed sealed chambers. The resection was completed in all leaflets and took, on average, 6.0 +/- 3.5 minutes per leaflet. The aortic wall was moderately injured in 4 of 10 cases and the aortic annulus in two cases with one aortic wall perforation. The surrounding tissue, the coronary ostia, the mitral valve, and the left ventricular outflow tract remained unaffected. CONCLUSION: This study demonstrates the feasibility of endovascular resection of human aortic valves in situ. This is a subsequent step toward complete percutaneous replacement (resection and implantation) of human aortic valves.

Percutaneous aortic valve replacement: endovascular sealing studies in situ.

OBJECTIVE: : To improve the outcome of percutaneous valve replacement in aortic stenosis endovascular resection of calcified aortic valves will be necessary. In this study different sealing methods were evaluated. The focus of this research was feasibility and mechanical functionality in human anatomy. METHODS: : The aortic valve isolation chamber (AVIC) is a catheter-based system to seal the aortic valve during resection, and was installed antegrade and retrograde. Firstly, AVIC was inserted antegrade via the cardiac apex in human postmortem models (n = 2), and secondly in porcine in vivo models under extra corporeal circulation (n = 5). Endoscopic inspection of the valve was recorded. AVIC was installed via a port system through the descending aorta. Micro- and macropathologies were performed. RESULTS: : AVIC transapical deployment in the two human models took 3 and 4 minutes respectively and 2.2 ± 1.3 minutes in average in the porcine model. From the descending aorta, the deployment took 9.3 ± 5.5 minutes. Fluoroscopy and macroscopy demonstrated sealed chambers. Microscopic and histologic analysis demonstrated no profound damages of the surrounding tissue. CONCLUSION: : This study demonstrates the feasibility of transapical and retrograde endovascular sealing of the aortic valve in vitro and in vivo in nonbeating hearts.

Percutaneous heart valve replacement: histology and calcification characteristics of biological valved stents in juvenile sheep.

INTRODUCTION: Percutaneous techniques to replace the pulmonary valve are emerging as an alternative to congenital cardiac surgical procedures. Promising experimental and early clinical results have been reported so far, focusing on technical feasibility and valved stent function. The present study aimed to describe the micropathology after experimental percutaneous valve replacement. METHODS: Self-expanding nitinol stents carrying a valved bovine jugular vein were transfemorally implanted into the pulmonary position of nine sheep. After 3 months of survival, macro- and micropathological examinations were carried out using standard staining techniques and immunohistochemistry. Additionally, calcification characteristics were determined by X-ray examinations and von Kossa stainings. RESULTS: Six of nine animals survived the 3-month study time with good angiographic and echocardiographic function. All valves were grossly functional at the time of explantation. Slight fibrous overgrowth was seen at the inflow portions of two valved stents. No cuspal perforations or intracuspal hematomas were observed. Light microscopy proved the absence of cellular inflammatory infiltrates in any tissue samples. The myocardium directly proximal to the stent appeared structurally normal without calcification. The overall structure of the native pulmonary artery was well preserved with few mineral deposits spread diffusely throughout the wall distal to the stent. Massive calcification appeared in the bovine jugular-vein wall together with increased numbers of T lymphocytes. Neither calcific deposits in the cusps nor extrinsic mineralization was noted. CONCLUSION: For the first time, micropathologic evaluation of percutaneously implanted heart valves is described. The results demonstrate that calcification of valved stents occurs in the wall portions without affecting the cusps. The cardiac structures in the vicinity had normal histology without inflammation.

Percutaneous pulmonary valve replacement: 3-month evaluation of self-expanding valved stents.

PURPOSE: In a recent study our group established an acute animal model of percutaneous pulmonary valve replacement using self-expanding nitinol stents. The present study was performed to evaluate these valved stents over a 3-month period. DESCRIPTION: Bovine jugular xenografts were sutured into nitinol stents. Transfemoral implantation in the pulmonary position using a modified commercially available application device (with a 22-French outer diameter) was evaluated in 9 sheep. EVALUATION: Two sheep died shortly after successful valved stent implantation due to internal venous hemorrhage. Another 1 sheep died 2.5 months after the procedure due to vegetations on the neovalve leading to subtotal stenosis. All other animals survived the 3-month study time (n = 6). An orthotopic pulmonary valved stent position was achieved in 4 animals and a supravalvular position in 1. During the deployment procedure, rhythm disturbances occurred in all animals, and mean arterial blood pressure dropped from 83.9 +/- 26.0 mm Hg to 68.3 +/- 22.3 mm Hg (p = 0.006) (n = 5). The peak-to-peak transvalvular gradient was 5.1 +/- 4.0 mm Hg initially (n = 5), and 3.6 +/- 1.6 mm Hg at follow-up (n = 5). Three-month angiographic and echocardiographic follow-up confirmed competent neovalves without paravalvular leakages. CONCLUSIONS: After 3 months of implantation, percutaneously implanted memory nitinol valved stents demonstrated good function in the sheep.

Percutaneous valve replacement: significance of different delivery systems in vitro and in vivo.

BACKGROUND AND PURPOSE: Percutaneous heart valve replacement is an exciting growing field in cardiovascular medicine yet still with some major problems. Only sophisticated improvement of the instruments could make it a real alternative to conventional surgery. Therefore, the aim of this study was to evaluate different delivery devices for percutaneous heart valve replacement in vitro and in vivo. METHODS: A catheter prototype designed by our group, and two commercially available devices for the delivery of esophageal stents and aortic endoprostheses, were tested. After in vitro experiments, an ovine animal model of transfemoral pulmonary valve implantation was established using biological valved self-expanding stents. Only the delivery device for aortic endografts (Medtronic, Talent, Santa Rosa, CA, USA) allowed fast in vitro procedures without material fatigue. This device was chosen for the in vivo tests. RESULTS: Technical success was achieved in 9 of 10 animals (90%). One animal died after perforation of the ventricular wall. Orthotopic pulmonary placement was performed in 6 animals and intentional supravalvular valved stent placement in 3 animals. CONCLUSIONS: An adequate in vitro model for this evolving field of interventional heart valve replacement is presented. Furthermore, the present study pinpoints the key characteristics that are mandatory for a delivery system in percutaneous pulmonary valve implantation. With regard to the delivery device's ductility observed during this "venous" study, an approach to transfemoral aortic valve implantation seems feasible.

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.

Percutaneous aortic valve replacement: resection before implantation.

OBJECTIVE: After transluminal endovascular implantation of a new valved stent, the aim of this study was to evaluate the feasibility of using a high-pressure water stream to endovascularly resect human calcified aortic valves. METHODS: First, human calcified aortic valves were excised and then resected in vitro to determine optimal water jet parameters. Second, healthy porcine aortic valves were ablated in vitro to evaluate possible destruction to the surrounding anatomy. Third, resection was performed endoluminally by introducing microsystemic tools into the descending aorta, passing them through the arch and ascending aorta to the aortic valve in an in vitro porcine model. Macro- and micropathology of specimens were analyzed. RESULTS: First, resection of human calcified valves took a mean of 6.0+/-2.4min per three leaflets at 150bar (n=17). The maximum size of the cut leaflets was 7.1+/-1.7mm. Second, resection of healthy porcine aortic valves at 60bar took 2.3+/-0.3min per three leaflets (n=10). Only the aortic annulus was moderately affected in six cases. Third, endoluminal resection via the descending aorta took 12.2+/-0.8min per three leaflets at 60bar (n=10). The aortic wall was affected in four cases, the aortic annulus and the coronary ostia only once. Microscopic analysis also revealed superficial lesions with a maximum lesion depth of 1200microm in one case, and an average of 580+/-145microm in subsequent lesions. The mitral valve and the left ventricular outflow tract were not affected. CONCLUSIONS: Percutaneous resection of heart valves is emerging as a promising auxiliary method for the resection of calcified aortic heart valves because they can be cut endoscopically. Nonetheless, before this resection tool can be clinically applied by surgeons to perform a true percutaneous valve replacement, an additional aortic valve resection chamber (already at the prototype stage) designed for capturing all debris, has to be established.

Change of the mechanical properties of two different balloon catheters with increasing numbers of cycles of resterilization.

An increasing number of centers are reusing PTCA catheters even though manufacturers warrant single use only. This prospective bench laboratory trial addresses the quality of PTCA balloon catheters after up to three resterilization cycles in order to determine whether a larger trial is warranted to discern whether catheters should be reused. Forty PTCA catheters from two different manufacturers (nominal diameters 1.5 and 3.0 mm) were taken from the shelf. An independent institute tested mechanical properties such as burst pressure, nominal diameter, crossing profile, and balloon surface. The crossing profile increased by 22.5%-39.2% with no additional deterioration after repeated sterilizations. The nominal diameter either increased or decreased by a maximum of 47%. In all 1.5 mm balloons, the burst pressure remained above the manufacturers' values, whereas in the 3.0 mm balloons, the value dropped below the rated burst pressure in 40%-50% of the trials. In conclusion, in both catheter types analyzed, reuse was associated with a considerably worse quality, which puts in question their routine clinical use.