No-react detoxification process: a superior anticalcification method for bioprostheses

Early and midterm outcomes of a bentall operation using an all-biological valved BioConduit™

OBJECTIVES

To analyze the midterm results of aortic root replacement using the valved, all biological, No React®, BioConduit™.

METHODS

From 2017 to 2020, we prospectively followed 91 consecutive patients who underwent a Bentall procedure with a BioConduit™ valved graft in our institution. The primary outcomes were aortic bioprosthetic valve dysfunction and mortality according to Valve Academic Research Consortium 3 (VARC3).

RESULTS

Mean age was 70 ± 10 years and 67 patients (74%) were men. Ascending aortic aneurysm (72%), aortic valve regurgitation (51%) or stenosis (20%) and acute endocarditis (14%) were the main indications for surgery. Seventy-four patients (81.3%) were followed up at 1 year. The perioperative mortality was 8% (n = 8), the early, 1 year, mortality was 2% (n = 2) and the midterm mortality, at 4 years of follow up, was 4% (n = 3). Ten patients fulfilled the criteria for hemodynamic valve deterioration at 1 year (13%) and 14 for a bioprosthetic valve failure during the entire follow-up (17%).

CONCLUSIONS

We are reporting early and midterm results of Bentall procedures with the all-biological, valved, No-React® BioConduit™. To our knowledge, this is the first study reporting an early and midterm unexpectedly high rate of non-structural prosthetic hemodynamic deterioration. The rate of endocarditis and atrioventricular disconnections remain similar to previous studies.

High incidence of fever in patients after biointegral pulmonic valved conduit implantation

OBJECTIVE

To describe our short- and medium-term outcomes using the BioIntegral pulmonic conduit.

METHODS

Between August 2018 and September 2019, the BioIntegral pulmonic valved conduit was used for right ventricular outflow tract reconstruction in 48 patients. The data were retrospectively retrieved from the patient charts.

RESULTS

The median age at surgery was 36 months (interquartile range [IQR] = 18-62 months). The diagnoses were pulmonary atresia-ventricular septal defect in 28 patients, absent pulmonary valve in four patients, truncus arteriosus in six patients, TGA-VSD-PS in five patients, conduit stenosis in three patients, and left venticular outflow tract obstruction requiring a Ross operation in two patients. In the postoperative short-term follow-up, 15 patients out of 48 had a high fever. Of these, 12 patients had concomitantly elevated C-reactive protein levels. There were no patients with blood culture positivity. The median postoperative length of hospital stay was 14 days (IQR = 8-21 days). The overall mortality was 4% in two patients, one died of right ventricular failure and multiple organ failure and one died of pulmonary embolism. The two patients who died were not among the 15 patients with fever. However, four patients with fever underwent balloon angioplasty for conduit restenosis in their medium-term follow-up.

CONCLUSION

There was a high incidence of fever and adverse outcomes in the short-term postoperative follow-up of patients in whom the BioIntegral pulmonic valved conduit was implanted. Caution is advisable in using these conduits until there is convincing evidence about the sterilization and storage standards of these grafts.

Long-term follow-up of the Shelhigh™ superstentless bioprosthesis aortic valve and valved conduit in a monocentric experience

BACKGROUND

The Shelhigh™ SuperStentless (Shelhigh, INC., Union, NJ, USA) is a stentless aortic valve bioprosthesis and aortic root valved conduit. In 2007, this device was recalled by FDA due to malfunction, and subsequently reintegrated by BioIntegral Surgical™ Few data are available over late durability of this device. We performed a long-term follow-up of Shelhigh™ devices implanted at our center.

METHODS

Between 2002 and 2007, 44 patients underwent aortic valve replacement with a Shelhigh™ device (40 aortic valve bioprosthesis and 4 valved conduit). We performed a clinical and echocardiographic follow-up (9.2 years±4.3). Standardized definitions of valve-related events were adopted.

RESULTS

At discharge, maximum and mean aortic gradients averaged 36.1±11.3 and 21.0±6.8 mmHg, respectively. The 30-days mortality was 2.3%. Over the follow-up period, 29 patients died (65.9%); 2 deaths were valve related. Overall survival at 1, 5 and 10 years was 97.7%, 85.8% and 54% respectively. At last echocardiography, average transvalvular gradients had remained globally stable in the population (33.6±12 and 20.4±10.5 mmHg). Eight (19%) structural valve deterioration (SVD) events were reported. Two (5%) non-structural valve dysfunction (NSVD) events occurred (periprosthetic leak). Two (5%) infectious endocarditis events and two (5%) valve thromboses were also deplored. Three (7%) patients required re-operation (2 due to SVD and 1 due to endocarditis).

CONCLUSIONS

The immediate hemodynamic performance of the Shelhigh™ aortic bioprostheses was unexpectedly suboptimal. Despite this, hemodynamic performance remained stable over time. Patients survival at follow-up was satisfactory, however, continued surveillance is necessary.

Long-term follow-up after Bentall operation using a stentless Shelhigh NR-2000 bio-conduit

BACKGROUND

To analyze the long-term results after Bentall operation using the stentless Shelhigh No-React (NR)-2000 bio-root prosthesis.

MATERIAL

From 2004 to 2008, 26 consecutive, nonselected patients (mean age at surgery: 67 ± 9 years) underwent a Bentall operation using a stentless Shelhigh valved conduit at our institution. Mean preoperative Logistic-EuroSCORE was 17.1 ± 12.9. The mean size of the aortic root was 53.2 ± 5 mm. The mean preoperative ejection fraction was 55 ± 7.4%. Three patients had a bicuspid valve. One patient with acute endocarditis and one patient with type A aortic dissection were operated on an emergency. Three patients (11.54%) had a previous cardiac operation. The Button-Bentall technique was used in all cases. Seven patients (26.92%) received an associated procedure. The mean size of the implanted prosthesis was 26.1 ± 2.2. Follow-up ranged between 6 and 174 months (mean 93.4 ± 59.1 months). Primary endpoints consisted of early and late mortality, freedom from acute endocarditis, freedom from structural valve deterioration, and freedom from valve-related-reoperation.

RESULTS

Two patients died in hospital, while 10 patients died during follow-up time, of which three for cardiac causes (12.5%). Overall survival probability was 52.9% at 15 years. Freedom from acute endocarditis was 95.7% at 5 and 15 years. Freedom from severe aortic incompetence due to structural deterioration was 100% at 5 and 10 years, 90.9% at 15 years. The mean aortic gradient at follow-up was 11.4 ± 5 mm Hg. Freedom from valve-related reoperation was 100% at 5 and 10 years, 90.9% at 15 years.

CONCLUSIONS

In our experience, Bentall's operation using the Shelhigh NR-2000 stentless bio-conduit provided satisfactory early and long-term results. However, our findings are not consistent with unfavorable long-term outcomes following the implantation of this device reported by other authors.

Mid-term single-center outcomes of BioIntegral compared to Freestyle aortic conduit implantation

BACKGROUND

Full aortic root replacement with biological conduit has limited options. This non-randomized cohort study aims to compare mid-term clinical and hemodynamic results of the BioIntegral (BI) composite biological versus the stentless Freestyle (FS) conduits in patients undergoing full aortic root replacement.

METHODS

From February 2013 to July 2017, 265 patients underwent aortic root replacement at a single institution (202 BI, 65 FS). Preoperative, intraoperative and postoperative parameters, complications including stroke, myocardial infarction (MI), endocarditis and reoperation were studied. Hemodynamic performance of both conduits was analyzed by echocardiography. Target endpoints were 30-day mortality, two-year survival, two-year freedom from major adverse valve-related and cardiovascular events.

RESULTS

Wider BI conduits were used (BI 27±2 vs. FS 25±2 mm, P<0.0001). The BI group had shorter cardiopulmonary bypass (BI 165±67 vs. FS 200±78 min, P<0.0001) and cross-clamp (BI 102±36 vs. FS 122±40 min, P=0.001) times. Thirty-day mortality was similar in both groups. There were fewer conduit-related reoperations in the BI group (BI 0% vs. FS 3%, P=0.012) but higher postoperative atrial fibrillation (BI 31% vs. FS 17%, P=0.025). No significant differences were observed for stroke (BI 5% vs. FS 10%, P=0.947), MI (BI 3% vs. FS 4%, P=0.583), or infective endocarditis (BI 0% vs. FS 2%, P=0.077). No significant hemodynamic differences were evident on follow-up echocardiography while an improved overall survival trend was seen in the BI group (P=0.062).

CONCLUSIONS

FS and BI provide comparable clinical mid-term results and hemodynamic parameters. Simplified implantation technique providing shorter cardiopulmonary bypass and operation times are advantageous for BI.

Surface-Immobilized Biomolecules on Albumin Modified Porcine Pericardium for Preventing Thrombosis and Calcification

The search for a noncalcifying tissue material to be used for valve replacement application continues to be a field of extensive investigation. A series of porcine pericardial membranes was prepared by modifying the glutaraldehyde - treated tissues with albumin and subsequently immobilizing bioactive molecules like PGE1, PGI2 or heparin via the carbodiimide functionalities. The in vitro calcification and collagenase degradation of these modified tissues were studied as a function of exposure time. Furthermore, the biocompatibility aspects of such novel interfaces were established by platelet adhesion and fibrinogen adsorption.

The results reported in this article propose that the treatment with antiplatelet agents such as albumin, heparin and prostaglandins (PGE1 or PGI2) change the surface conditioning of pericardial tissues, suggesting a possible role of deposited serum components in affecting mineralization process on bioprosthesis. Therefore, it is worthy to hypothesize that besides inhibiting the accumulation of calcium in the devitalized cells, the early formation of a conditioning layer on the bioprosthesis surface may affect salt precipitations, determining the propensity of the implant to calcify. More detailed studies are needed to understand the involvement of plasma proteins and cellular components of the recipient blood in tissue-associated calcification.

Initial experience with xenograft bioconduit for the treatment of complex prosthetic valve endocarditis

INTRODUCTION

The treatment of complex prosthetic valve endocarditis (PVE) with aortic root abscess remains a surgical challenge. Several studies support the use of biological tissues to minimize the risk of recurrent infection. We present our initial surgical experience with the use of an aortic xenograft conduit for aortic valve and root replacement.

METHODS

Between October 2013 and August 2015, 15 xenograft bioconduits were implanted for complex PVE with abscess (13.3% female). In 6 patients, concomitant procedures were performed: coronary bypass (n=1), mitral valve replacement (n=5) and tricuspid annuloplasty (n=1). The mean age at operation was 60.3±15.5 years. The mean Logistic European system for cardiac operating risk evaluation (EuroSCORE) was 46.6±23.6. The median follow-up time was 607±328 days (range: 172-1074 days).

RESULTS

There were two in-hospital deaths (14.3% mortality), two strokes (14.3%) and seven patients required permanent pacemaker insertion for conduction abnormalities (46.7%). The mean length of hospital stay was 26 days. At pre-discharge echocardiography, the conduit mean gradient was 9.3±3.3mmHg and there was either none (n=6), trace (n=6) or mild aortic insufficiency (n=1). There was no incidence of mid-term death, prosthesis-related complications or recurrent endocarditis.

CONCLUSIONS

Xenograft bioconduits may be safe and effective for aortic valve and root replacement for complex PVE with aortic root abscess. Although excess early mortality reflects the complexity of the patient population, there was good valve hemodynamics, with no incidence of recurrent endocarditis or prosthesis failure in the mid-term. Our data support the continued use and evaluation of this biological prosthesis in this high-risk patient cohort.

Suitability of the rat subdermal model for tissue engineering of heart valves

BACKGROUND

Tissue engineering (TE) is a promising approach to overcome problems associated with biological heart valve prosthesis. Currently several animal models are used to advance this method. The rat subdermal model is uncomplicated and widely used, but its suitability for TE has not yet been shown.

MATERIAL AND METHODS

Using the rat subdermal model we implanted two decellularized porcine aortic wall specimens (of which one was endothelialized) and one native porcine aortic wall specimen in 30 Lewis rats, respectively. Endothelial cells (EC) were harvested from the rat jugular veins. After explantation Hematoxylin/Eosin-staining, CD-68-positive cell staining, fibroblast-staining and Von-Willebrand factor staining were performed.

RESULTS

All animals survived without complications. Endothelialization was confirmed to be effective by Giemsa staining. Histological evaluation of specimens in Hematoxylin/Eosin staining showed significant decrease (p<0.05) of inflammatory reaction (confirmed by CD-68-positive cell staining) after decellularization. All specimens showed strongest inflammatory reactions at areas of destroyed extracellular matrix. Fibroblasts could be detected in all specimens, with strongest infiltration in decellularized specimens (p<0.05). Surrounding endothelialized specimens had no monolayer of endothelial cells, but a higher density of blood vessels occurred (p<0.05).

CONCLUSIONS

The subdermal model provides excellent contact of host tissue with implanted specimens leading to rapid cellular infiltration; therefore, we could ascertain reduced inflammatory response to decellularized tissue. Due to the subdermal position, an absence of blood stream and mechanical stress occurs, which influences cellular repopulation; therefore, endothelialization did not lead to an EC monolayer, but rather to increased vascularization. Thus, the model appears ideal for investigating basic biological compatibility, but further questions must be researched using other models.

Totally biological composite aortic stentless valved conduit for aortic root replacement: 10-year experience

Objectives

To retrospectively analyze the clinical outcome of a totally biological composite stentless aortic valved conduit (No-React^® BioConduit) implanted using the Bentall procedure over ten years in a single centre.

Methods

Between 27/10/99 and 19/01/08, the No-React^® BioConduit composite graft was implanted in 67 patients. Data on these patients were collected from the in-hospital database, from patient notes and from questionnaires. A cohort of patients had 2D-echocardiogram with an average of 4.3 ± 0.45 years post-operatively to evaluate valve function, calcification, and the diameter of the conduit.

Results

Implantation in 67 patients represented a follow-up of 371.3 patient-year. Males were 60% of the operated population, with a mean age of 67.9 ± 1.3 years (range 34.1-83.8 years), 21 of them below the age of 65. After a mean follow-up of 7.1 ± 0.3 years (range of 2.2-10.5 years), more than 50% of the survivors were in NYHA I/II and more than 60% of the survivors were angina-free (CCS 0). The overall 10-year survival following replacement of the aortic valve and root was 51%. During this period, 88% of patients were free from valved-conduit related complications leading to mortality. Post-operative echocardiography studies showed no evidence of stenosis, dilatation, calcification or thrombosis. Importantly, during the 10-year follow-up period no failures of the valved conduit were reported, suggesting that the tissue of the conduit does not structurally change (histology of one explant showed normal cusp and conduit).

Conclusions

The No-React^® BioConduit composite stentless aortic valved conduit provides excellent long-term clinical results for aortic root replacement with few prosthesis-related complications in the first post-operative decade.

64-slice computed tomography of bovine internal mammary artery coronary grafts

In cases where conventional aortocoronary grafts cannot be used, No-React bovine internal mammary artery is a possible alternative. The aim of this study was to assess the patency and clinical performance of bovine internal mammary artery as a coronary bypass conduit, using 64-slice computed tomography coronary angiography. Eleven patients (mean age, 68.2 + or - 5.9 years) received 11 bovine grafts between 2002 and 2006. Eight of these patients were alive after a mean follow-up of 29.4 + or - 16.3 months. Their mean additive EuroSCORE was 6.5 + or - 3.2. The mean number of distal anastomoses was 2.5 + or - 0.5. Six grafts were anastomosed to the right coronary artery, 2 to the left anterior descending artery, and 3 to the circumflex artery. All 11 bovine grafts were found to be occluded after 14.1 + or - 3.6 months. This demonstrates very poor results with the bovine coronary graft, thus we do not recommend its use, and we suggest considering an hybrid approach in selected cases.

Follow-up of Shelhigh porcine pulmonic valve conduits

BACKGROUND

We implanted Shelhigh porcine pulmonic valve conduits because of the limited availability of homografts in our country. The aim of this study was to evaluate the short-term results of SPVC.

METHODS

From November 2002 to July 2005, the Shelhigh porcine pulmonic valve conduit was implanted in 73 patients (81 procedures) in the right ventricular outflow tract to correct congenital heart diseases. Operative procedures were Rastelli operation in 65, anatomic correction of atrioventricular discordance in 5, and Ross operation in 3. Age at operation was 6.8 +/- 7.5 years, including 11 patients under 1 year. The median conduit size was 18 mm (range, 12 to 24 mm).

RESULTS

There was no operative mortality and 1 nonconduit-related late death (mean follow-up, 11.3 +/- 10.7 months). Ten conduits (12.3%, 7 patients) were removed at a median of 9.6 months (range, 2.5 to 25.4) owing to obstruction in 9 and pseudoaneurysm in 1. In the explanted conduits, we found a prominent intimal peel at the distal anastomosis without leaflet calcification. Freedom from reoperation at 24 months was 87% +/- 11.7% in large-sized conduits (>or=18 mm) and 62.8% +/- 10.6% in small-sized conduits (<or=16 mm). Especially, 12-mm sized conduit showed 33.3% freedom from reoperation during the first 12 months of follow-up.

CONCLUSIONS

On the basis of our short-term results, Shelhigh porcine pulmonic valve conduits are not satisfactory. Small-sized conduits (<or=16 mm) fail earlier; large-sized conduits (>or=18 mm) fail after 2 years of implantation due to intimal peel formation at the distal segment.

First report of no-react bovine internal mammary artery performance and patency

BACKGROUND

No-React treatment is known to render tissues resistant to calcific degeneration and to reduce early inflammatory response. No-React bovine internal mammary artery (NR-IMA) is available for restricted use in Europe. In this first study, our aim was to use magnetic resonance imaging (MRI) to investigate the clinical performance and patency rates of this conduit.

METHODS

Seven patients received 8 grafts with NR-IMA. Approval from the Medical Devices Agency of the United Kingdom was obtained for use of this material. One patient needed salvage coronary artery bypass grafting (CABG). Graft patency was investigated with cardiac MRI. One patient was excluded from the MRI study because of the presence of intracerebral metal clips. The mean follow-up period was 2.5 years with a range of 1 to 4.5 years.

RESULTS

There was no mortality in this group. After treatment 6 patients were asymptomatic, and 1 patient had class II anginal symptoms. Four (57%) of the 7 NR-IMA grafts remained patent. The longest patency was 4.5 years in a patient who underwent salvage CABG. Other associated grafts in this cohort of patients were 5 left internal mammary arteries (all patent), 1 radial artery graft (patent), and 7 saphenous vein grafts (4 [57%] of 7 patent). There were no occluded NR-IMA grafts in a patient with patent vein grafts.

CONCLUSION

We concluded that at 2.5 year follow-up, NR-IMA had a patency rate of 57% (4 of 7 cases). This rate matched the vein graft patency rate in this cohort of patients. With the longest patency of 4.5 years, use of NR-IMA seems to hold promise for the future.

Early and mid–term results of the Shelhigh stentless bioprosthesis in patients with active infective endocarditis

AIMS

This study investigated the early and mid-term results following valve replacement with the new Shelhigh stentless bioprosthesis made entirely of biological material in patients with active infective endocarditis (AIE).

MATERIAL AND METHODS

Between 02/2000 and 12/2004, 164 patients (n = 122 men, mean age 59, 18-85 years) received implantation of an AIE Shelhigh stentless bioprosthesis in the aortic, mitral, tricuspid or pulmonary position. A total of 119 patients (72.6%) had native AIE and 45 (27.4%) prosthetic AIE. A large proportion of the patients reached the operating room in a condition of cardiac decompensation: 37 (22.6%) patients were intubated, 40 (24.4%) had protracted septic shock and 41 (25.0%) required intensive catecholamine treatment. Surgery was regarded as urgent in 94 patients (57.4%) and was performed as an emergency procedure in 70 (42.6%). The mean follow-up time is 1.5 +/- 0.11 years (range, 5 months to 5.2 years). Echocardiographic follow-up examinations were performed early postoperatively and after 12 months.

RESULTS

In terms of the operative indication, we found a highly significant difference in the survival rate between patients who were operated on urgently vs in an emergency. In patients who died within 30 days, the main cause of death was septic multiorgan failure (67.6%). Only three patients required reoperation due to reinfection of the Shelhigh bioprostheses; this represents a reinfection rate of 1.8% in relation to the whole cohort. The postoperative echocardiographic examinations showed the Shelhigh valves to have very good hemodynamics without relevant pressure gradients.

CONCLUSION

Our experience in the use of Shelhigh bioprostheses in patients with native and prosthetic endocarditis show the early and mid-term results, in particular the low reinfection rate and the good hemodynamics, to be comparable with the results achieved using homografts. Since these prostheses are readily available and their implantation straightforward, they are increasingly being used in patients with endocarditis. These promising results need to verified in the long term.

Prevention of calcification in bioprosthetic heart valves: challenges and perspectives

Surgical replacement with artificial devices has revolutionised the care of patients with severe valvular diseases. Mechanical valves are very durable, but require long-term anticoagulation. Bioprosthetic heart valves (BHVs), devices manufactured from glutaraldehyde-fixed animal tissues, do not need long-term anticoagulation, but their long-term durability is limited to 15 - 20 years, mainly because of mechanical failure and tissue calcification. Although mechanisms of BHV calcification are not fully understood, major determinants are glutaraldehyde fixation, presence of devitalised cells and alteration of specific extracellular matrix components. Treatments targeted at the prevention of calcification include those that target neutralisation of the effects of glutaraldehyde, removal of cells, and modifications of matrix components. Several existing calcification-prevention treatments are in clinical use at present, and there are excellent mid-term clinical follow-up reports available. The purpose of this review is to appraise basic knowledge acquired in the field of prevention of BHV calcification, and to provide directions for future research and development.

Factors Influencing the Results of Double-Valve Surgery in Patients with Fulminant Endocarditis: The Importance of Valve Selection

BACKGROUND

Extension of infection below the aortic valve is a serious complication, especially with mitral valve involvement. Mortality is substantial and reinfection can strongly influence outcome.

PATIENTS

Of 327 surgical patients with active infective aortic valve endocarditis admitted to the Deutsches Herzzentrum Berlin for surgical treatment between December 1996 and December 2003, 108 had root abscess, and 53 (25.5%) had diagnoses of secondary infective mitral valve disease (SMVD). The mean age (+/-SD) was 53 +/- 14.2 years; there were 37 men and 16 women.

METHODS

The secondary lesion on the mitral valve was classified as SMVD requiring double-valve surgery (DVS). This prospective clinical and echocardiographic study revealed 2 paths of infection extension into the mitral valve. In the DVS group, 38 patients (71.7%) had tissue metastatic lesions, and 15 patients (28.3%) had a jet lesion on the mitral valve. Most patients (42) with SMVD had an aortic ring abscess as the primary lesion.

RESULTS

All patients with destructive endocarditic doublevalve disease received aortic and mitral valve surgery. In 19 cases (35.8%), mitral valve reconstruction was undertaken; in 4 cases, mitral valve replacement had to be carried out after attempted mitral valve reconstruction. Concomitant mitral valve replacement because of severe damage to the valvular and subvalvular apparatus was performed in 30 patients (56.6%). Other types of surgery performed in 11 cases (20.8%) were 8 closures of a septic ventricular septal defect and 3 closures of a fistula to the right ventricle or right atrium. Twenty-seven patients were treated with a Shelhigh prosthesis, 18 were treated with double-valve replacement (both Shelhigh), and 9 were treated with an aortic Shelhigh prosthesis and concomitant mitral valve reconstruction. Homografts were used in 17 patients, with mitral valve reconstruction carried out in 10 patients and a stented mitral prosthesis in 7. In 9 cases, 2 stented valve prostheses were used. There were 14 early (60 days) deaths (26.4%). Septic shock, severe annular and subannular destruction, and poor left ventricular function (end-diastolic dimension >65 mm, ejection fraction <40%) were the significant risk factors determined in the multivariate analysis. Function of Implants: Continuous and Color Doppler Investigation: Comparative studies of 2 different implants in the aortic position were performed late postoperatively (325 +/- 251 days) for homografts and the Shelhigh stentless prosthesis. The calculated instantaneous (maximal Doppler) gradient and the mean pressure gradient through the aortic implants were 19 +/- 10.4 mm Hg and 12 +/- 5.7 mm Hg, respectively, for the homografts and 24 +/- 8.4 mm Hg and 15 +/- 4.6 mm Hg, respectively, for the Shelhigh stentless prosthesis (not significantly different for the 2 groups). There was no mitral or aortic valve dysfunction. A trivial paravalvular leakage in the mitral position in 1 patient and a pseudoaneurysm of the left ventricular out- flow tract without leakage or valvular dysfunction in another were diagnosed by postoperative Doppler investigation.

CONCLUSIONS

The mortality in patients with destructive endocarditis requiring DVS depends mostly on the patients' preoperative hemodynamic situation. The risk of reinfection can be minimized if valve substitutes are properly selected (homografts, Shelhigh No-React SuperStentless and No-React BioConduit in the aortic position, or Shelhigh BioMitral in the mitral position). Concomitant mitral valve reconstruction procedures do not increase the risk of mitral reinfection.

A new nonabsorbable adhesion barrier for myomectomy

BACKGROUND

A pilot study was made to assess the efficacy and safety of a new nonabsorbable adhesion barrier (Shelhigh Dome Pericondial Patch No-React Treated) in reducing adhesion after extensive myomectomy by laparotomy with a planned second-look laparoscopy.

METHODS

In 20 patients after extensive myomectomy and full thickness uterine wall reconstruction, the patch was sutured over the uterus. Second-look laparoscopy was performed 6 weeks postoperatively. Third-look laparoscopy was done in 3 patients.

RESULTS

Surgeries were completed without intraoperative or postoperative complications. No problems related to the patch were encountered including the need for its removal. At laparoscopy no adhesions between the abdominal wall, bladder, small bowel, or sigmoid colon to the uterus were noticed. A thin layer of the omental edge covered the patch that was securely anchored to the uterine fundus. The mean follow-up was 13 months.

CONCLUSIONS

These findings suggest benefits with this new bovine/porcine pericardial adhesion barrier for myomectomy. Controlled clinical trials are warranted.

Long-term results after aortic valve replacement with the Biocor PSB stentless xenograft in the elderly

BACKGROUND

This study seeks to define the long-term results after Biocor PSB stentless aortic valve replacement (AVR) in elderly patients, including the effects of No-React treatment.

METHODS

We reviewed the outcomes of 106 consecutive patients, aged 70+/-6 years, having Biocor PSB (93 standard, 13 No-React) AVR between October 1992 and October 1996.

RESULTS

There were three early deaths (3%) and 15 late deaths (15%), during a mean follow-up of 5.8+/-1.6 years. At 8 years, survival was 82%+/-4% and freedom from cardiac death was 94%+/-3%. Freedom from valve failure was 92%+/-4% at 8 years (No-React: 92%+/-8% at 4 years). Replacement of the xenograft was required in 5 patients. Freedom from reoperation was 91%+/-4% at 8 years (No-React: 92%+/-8% at 4 years). Four bleeding and two embolic events were recorded: overall valve-related event-free survival was 81%+/-7% at 8 years (No-React: 76%+/-12% at 4 years). Age of long-term survivors averaged 77+/-5 years and their New York Heart Association status was 1.3+/-0.6 (versus 2.9+/-0.6 preoperatively, p = 0.01).

CONCLUSIONS

Satisfactory freedom from cardiac events and from valve deterioration added to uniform improvement in functional status despite advanced age and high prevalence of comorbid conditions make AVR with the Biocor PSB xenograft a valid long-term therapy for the elderly. No-React treatment does not influence xenograft durability.

Calcification and degeneration characteristics of the Biocor no-react bovine internal mammary artery (BIMA) - in vivo evaluation in a sheep model

OBJECTIVE

The No-React process for biomaterials was suggested to prevent calcification and degeneration. We examined in vivo in a chronic sheep model the performance of a Biocor bovine internal mammary artery (BIMA) graft after No-React processing.

METHODS

'No-React' processing consists of aldehyde cross-linkage following a detoxification process with multiple physical variables and incubation with surfactant. Biocor BIMA No-React treated grafts have been interposed in the carotid artery in seven sheep with a Dacron graft as control. Grafts were explanted after 3 or 6months and were grossly examined, by X-ray, histology, transmission and scanning electron microscopy, and atomic absorption spectrophotometry.

RESULTS

In the BIMA, good healing was found with a smooth intimal surface, minimal inflammatory reaction, and a well preserved ultrastructure. Calcification increased progressively. In the Dacron grafts, a fibrous covering the inner surface and infiltration with fibroblasts, histiocytes and macrophages was noted. Calcium content was stable.

CONCLUSION

Calcification increased progressively in Biocor BIMA No-React grafts. Minimal inflammatory changes, a smooth inner surface and well preserved ultrastructure were noted.

Shelhigh No-React porcine pulmonic valve conduit: a new alternative to the homograft

BACKGROUND

The Shelhigh No-React pulmonic valve conduit is a new porcine conduit that is glutaraldehyde-treated and detoxified using a proprietary heparin process. In our institution it has been implanted in 25 patients. The aim of this present contribution is to evaluate the short-term follow-up after its implantation.

METHODS

From November 1997 to August 1999, 25 patients (mean age, 20.2 years; range, 0.6 to 28.3 years) were operated on using this conduit. Seventeen patients underwent a Ross procedure for aortic valve disease, with the conduits implanted in anatomic position; 6 patients underwent right ventricular outflow tract reconstruction; 2 patients underwent the Rastelli operation. The follow-up was complete. Preoperative and postoperative two-dimensional echocardiography data were collected.

RESULTS

There were two non-conduit-related deaths. Two conduits needed to be exchanged because of an increase in the gradient. Overall, all patients were improved in terms of New York Heart Association class. Comparison of preoperative and postoperative two-dimensional echocardiography gradient showed significant improvement. At the 30-month follow-up, no calcification was seen on the explanted conduits or on the two-dimensional echocardiography, although many of the patients are children.

CONCLUSIONS

The Shelhigh conduits seem to be an alternative to homograft especially in infants. These experiences are preliminary, and longer follow-up is required.

Evaluation of a porcine internal mammary artery (No-React II) as a small-diameter conduit

BACKGROUND

The patency of biologic small-diameter vascular grafts in the aortocoronary position is still unsatisfactory. Most of the studies suggest that xenografts are to be avoided as an aortocoronary bypass.

METHODS

The porcine internal mammary artery treated by the No-React II procedure was developed for use as an alternative coronary artery bypass conduit. The attempt of this study was to evaluate the patency and histologic changes of the porcine internal mammary artery in animals. Five calves underwent coronary artery bypass grafting with a porcine internal mammary artery graft to the right coronary artery. After euthanasia of the animals 103 days later, the samples of these grafts were studied morphologically for patency, structural changes, calcifications, and inflammatory and immunologic response.

RESULTS

One animal died during the procedure as result of acute thrombosis of the porcine internal mammary artery graft. In the other 4 animals all grafts became occluded. In the histologic sections of the grafts we noted multiple calcifications and a host-graft immunologic reaction (severe chronic rejection).

CONCLUSIONS

The present study demonstrates a very poor experience with the porcine internal mammary artery (No-React II) conduit. We do not recommend this prosthesis for clinical use in humans.

Aortic pulmonary autograft implant: medium-term follow-up with a note on a new right ventricular pulmonary artery conduit

BACKGROUND

The Ross operation has been applied to various aortic valve pathologies, particularly when somatic growth is an issue. However, associated cardiac disease and technical problems may limit its use with regard to associated procedures and issues of right ventricular outflow reconstruction.

MATERIALS AND METHODS

From December 1992 to March 1998, 24 patients underwent aortic pulmonary autograft implantation. There were 14 males and 10 females, 15+/-10 years of age (mean +/- SD) (range 1 to 50 years), weighing 42.8+/-20 kg (mean +/- SD) (range 8 to 78 kg). Aortic insufficiency was present in 15 (62.5%) patients, stenosis in 8 (33.3%) patients, and valvar stenosis associated with left ventricular outflow tract obstruction in 1 (4.1%) patient. Etiology was rheumatic in 17 patients and congenital in 7. The Ross procedure was accompanied by a partial-Konno left ventricular outflow enlargement in one patient, and mitral valve annuloplasty, mitral commissurotomy, and tricuspid valve replacement in three other patients, respectively. The right ventricular outflow was reconstructed with a valved pulmonary homograft in 14 patients and with a Shelhigh No-React porcine pulmonary conduit in 10 patients. Evaluation was done by New York Heart Association (NYHA) Class and by echocardiography at a follow-up of 22.8+/-24 months (mean +/- SD) (range 3 to 63 months).

RESULTS

There were no operative mortalities and no postoperative arrhythmias. One (4.1%) patient required intra-aortic balloon pump (IABP) support for 3 days, one (4.1%) patient died 2 years later of probable arrhythmia, and one (4.1%) patient required mechanical aortic valve replacement 2 years later for severe autograft insufficiency. Left ventricular ejection fraction was unchanged (preoperative 62.4%+/-30%, postoperative 64.2%+/-30% [mean +/- SD], [p = NS]) and no significant gradient was documented by echocardiographic Doppler in the right and left ventricular outflow tracts. The aortic insufficiency scale decreased from a mean of 3.9+/-0.2 to a mean of 1+/-0 (p < 0.01). NYHA Class decreased to I in all patients, from III (10) and II (14).

CONCLUSIONS

The pulmonary autograft in the aortic position is suitable for aortic valve replacement in pediatric and adult patients with good medium-term results and in patients with rheumatic etiology, and it provides a desirable solution in the presence of associated pathologies, such as left ventricular tract obstruction or associated multivalvular disease. The development of new means of right ventricular outflow reconstruction must parallel the progress achieved for the left side.