Valved Conduit Research Articles

Aortic Root Replacement With Autologous Pericardium Valved Conduit

Available aortic prosthesis replacement options present a challenge to achieving low perioperative morbidity, low pressure gradients, and prolonged durability. Trileaflet aortic valve reconstruction using autologous pericardium offers an alternative treatment option with excellent postoperative gradients, large effective orifice areas, and the avoidance of long-term anticoagulation. The modified Bentall procedure with either tissue xenograft valved conduit or mechanical valved conduit is considered the gold standard for patients with aortic root pathology requiring surgical replacement. We report a novel adaptation of the modified Bentall procedure with a self-fabricated valved conduit with trileaflet aortic valve neocuspidization using autologous pericardium.

A decellularized porcine pulmonary valved conduit embedded with gelatin.

To prepare a tissue-engineered pulmonary valved conduit (PVC) with good tensile strength and biocompatibility. Sixty adult porcine PVCs were used to determine the optimal decellularization time. Five juvenile porcine decellularized PVCs and five juvenile porcine crosslinked PVCs were subsequently prepared according to the optimized decellularization and crosslinking methods. All PVCs were implanted into juvenile sheep for 8months and then were harvested for staining. With a low concentration of detergent (0.25% Triton X-100+0.25% sodium deoxycholate), the decellularization effect on porcine PVCs was complete by 24hours, and there was minimal damage to the matrix. Gelatin embedding and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) crosslinking improved the biomechanical properties of decellularized PVCs and reduced their immunogenicity. After implantation, the diameter and thickness of the PVCs in the decellularized and crosslinked groups increased significantly. In both groups, the conduits were unobstructed, with soft and smooth inner walls and without thrombosis, ulceration or neoplasia. The valves slightly degenerated with mild to moderate regurgitation. CD31-positive endothelial cells were visible on the inner surface of the conduits and valves. Scattered smooth muscle actin-positive cells were found in the middle layer of the conduit. The percentage of CD4- and CD68-positive cells and the calcium content were highest in decellularized porcine PVCs and lowest in ovine PVCs. The percentage of the matrix that was laminin-positive in decellularized and crosslinked porcine PVCs was lower than it was in ovine PVCs. Gelatin-embedded and EDC-crosslinked porcine PVCs can be "hosted" in sheep, with good biocompatibility, growth potential, and reduced calcification.

Tissue Remodeling of Engineered Valved Conduit Evaluated at 52 Weeks in the Growing Lamb

Objective: Tissue-engineered valved conduits that can resist calcification and degradation while allowing somatic growth would provide an ideal solution for congenital valve replacement. The goal of this study was to assess remodeling of conduits made from acellular engineered matrix manufactured from allogeneic fibroblasts. Methods: Three 16mm diameter tubes of engineered tissue were stitched together with Maxon degradable sutures to create a novel tri-leaflet valved conduit. The valved conduit was implanted as a pulmonary replacement in 7 lambs (average age 15.5 wk) up to 12 months. Conduits explanted after 12 - 52 weeks were evaluated histologically and biochemically for matrix remodeling and calcification. Results: The valved conduits explanted at the earliest timepoint of 12 weeks showed degradation of Maxon sutures indicating matrix remodeling was providing the load-bearing properties at resorbing suture lines. The conduit increased in diameter over the implant duration. Collagen and protein concentrations in the wall of the conduit at 52 weeks were increased. Histology showed recellularization of the wall matrix with αSMA+ interstitial cells and CD31+ endothelial cells on the lumen surface. The leaflet matrix showed no change in the collagen or protein concentration compared to the implant. The cell concentration in the leaflet matrix increased from zero at implant to 34±10M cells/cm3 at the 52 week explant. Cells on the leaflet surface were also CD31+. Von Kossa stain showed no calcification other than near Maxon sutures and sparse punctate micro-calcification in two valves. Conclusions: This 1-yr study of a valved conduit implanted in a growing lamb demonstrated extensive matrix remodeling both to provide load-bearing capabilities at the degradable suture lines and new extracellular matrix to confer somatic growth. Combined with a lack of macro-calcification over the 1-yr implantation are promising outcomes to support the use of this acellular engineered matrix for potential pediatric use.

Biologically-engineered Pediatric Tri-tube Valved Conduit Evaluated 52 Weeks in the Growing Lamb

Objective: There is a dire need for a heart valve that can grow with children. We fabricated tubes of biologically-engineered matrix that have been shown to regenerate and grow as a pulmonary artery replacement in lambs, and implemented a novel design for a valved conduit made from sewing three of these tubes together with degradable suture that confers valve growth potential. The study was to assess valve function and growth potential over a one-year period in the lamb model. Methods: Seven lambs were implanted with tri-tube valved conduits in sequential cohorts and compared to bioprosthetic conduits using longitudinal echocardiography and histological and mechanical characterization post-explantation. Results: Valves implanted in two lambs of the first cohort of four animals functioned with only mild regurgitation and systolic pressure drops <10 mmHg up to 52 weeks post-implantation, during which the valve diameter increased from 19 mm to a normal ~25 mm. In a second cohort of three animals, an additional tube was used to create a sleeve around the tri-tube valve to counteract faster root growth relative to the leaflets. Two valves exhibited only trivial-to-mild regurgitation at 52-weeks with similar diameter increase and systolic pressure drops of < 5 mm Hg. The same was true for the third animal until moderate regurgitation at 52 weeks correlating to hyper-increase of the valve diameter. In all explanted valves, the leaflets remained thin and pliable with only sparse, punctate microcalcification at most, and they contained interstitial cells and an endothelium progressing from the base of the leaflets. Conclusions: These results are demonstrably improved in terms of calcification and hemodynamic function compared to reported studies for clinically-used pediatric bioprosthetic valves tested in the same model. The results demonstrate the potential for long-term valve growth of this “off-the-shelf” tri-tube valved conduit in children.

EuroScore and IL-6 predict the course in ICU after cardiac surgery

BackgroundDespite modern advances in intensive care medicine and surgical techniques, mortality rates in cardiac surgical patients are still about 3%. Considerable efforts were made to predict morbidity and mortality after cardiac surgery. In this study, we analysed the predictive properties of EuroScore and IL-6 for mortality in ICU, prolonged postoperative mechanical ventilation, and prolonged stay in ICU.MethodsWe enrolled 2972 patients undergoing cardiac surgery. The patients either underwent aortic valve surgery (AV), mitral valve surgery (MV), coronary artery bypass grafting (CABG), and combined operations of aortic valve and coronary artery bypass grafting (AV + CABG) or of mitral and tricuspid valve (MV + TV). Different laboratory and clinical parameters were analysed.ResultsEuroScore as well as IL-6 were associated with increased mortality after cardiac surgery. Furthermore, a higher EuroScore and elevated levels of IL-6 were predictors for prolonged mechanical ventilation and a longer stay in ICU. Especially, highly significant elevated IL-6 levels and an increased EuroScore showed a strong association. Statistics suggested superiority when both parameters were combined in a single model.ConclusionOur results suggest that EuroScore and IL-6 are helpful in predicting the course in ICU after cardiac surgery, and therefore, the use of intensive care resources. Especially, the combination of highly elevated levels of IL-6 and EuroScore may prove to be excellent predictors for an unfortunate postoperative course in ICU.

Pediatric tri-tube valved conduits made from fibroblast-produced extracellular matrix evaluated over 52 weeks in growing lambs.

There is a need for replacement heart valves that can grow with children. We fabricated tubes of fibroblast-derived collagenous matrix that have been shown to regenerate and grow as a pulmonary artery replacement in lambs and implemented a design for a valved conduit consisting of three tubes sewn together. Seven lambs were implanted with tri-tube valved conduits in sequential cohorts and compared to bioprosthetic conduits. Valves implanted into the pulmonary artery of two lambs of the first cohort of four animals functioned with mild regurgitation and systolic pressure drops <10 mmHg up to 52 weeks after implantation, during which the valve diameter increased from 19 mm to a physiologically normal ~25 mm. In a second cohort, the valve design was modified to include an additional tube, creating a sleeve around the tri-tube valve to counteract faster root growth relative to the leaflets. Two valves exhibited trivial-to-mild regurgitation at 52 weeks with similar diameter increases to ~25 mm and systolic pressure drops of <5 mmHg, whereas the third valve showed similar findings until moderate regurgitation was observed at 52 weeks, correlating to hyperincrease in the valve diameter. In all explanted valves, the leaflets contained interstitial cells and an endothelium progressing from the base of the leaflets and remained thin and pliable with sparse, punctate microcalcifications. The tri-tube valves demonstrated reduced calcification and improved hemodynamic function compared to clinically used pediatric bioprosthetic valves tested in the same model. This tri-tube valved conduit has potential for long-term valve growth in children.

Better preoperative exercise function is associated with shorter hospital stay after paediatric pulmonary valve replacement or conduit revision.

Single centre retrospective cohort study of patients aged 8-18 years who underwent surgical pulmonary valve replacement. The primary predictor was preoperative percent predicted peak oxygen consumption, and primary outcome was total hospital length of stay. Clinical, imaging, and cardiopulmonary exercise test data were reviewed and compared to total hospital length of stay. Cox proportional hazards regression was used to examine the association between total hospital length of stay and percent predicted peak oxygen consumption. Three-hundred and seventy patients undergoing pulmonary valve replacement/conduit change between 2003 and 2017 at Boston Children's Hospital were identified. Ninety had preoperative cardiopulmonary exercise tests within 6 months of surgery. Exclusion for inadequate exercise data (n = 3) and imaging data (n = 1) left 86 patients for review. Patients with percent predicted peak oxygen consumption ≥ 70% (n = 46, 53%) had shorter total hospital length of stay (4.4 days) than the 40 with percent predicted peak oxygen consumption <70% (5.4 days, p = 0.007). Median percent predicted peak oxygen consumption increased over sequential surgical eras (p < 0.001), but total hospital length of stay did not correlate with surgical era, preoperative left ventricular function, or preoperative right ventricular dilation. Children undergoing surgical pulmonary valve replacement with better preoperative exercise capacity had shorter total hospital length of stay. Exercise capacity is a potentially modifiable factor prior to and after pulmonary valve replacement. Until more patients systematically undergo cardiopulmonary exercise tests, the full impact of optimisation of exercise capacity will not be known.

Management of a mechanical aortic valve during left ventricular assist device implantation in a previously replaced aortic root.

The use of left ventricular assist device (LVAD) in patients with mechanical aortic valves may result in thromboembolic events due to blood stasis around the valve and intermittent valve opening. Mechanical aortic valves encountered during LVAD implantation are managed by replacement with a tissue valve, or closure of the valve with a patch. Closure of the valve carries the risk of sudden death in cases of LVAD stoppage. Replacing the whole mechanical valve conduit is time consuming and carries a significant risk of bleeding and right ventricular (RV) failure. We describe an alternative technique of replacing a mechanical aortic valve by breaking its inner leaflets and sewing a tissue valve on top of the mechanical valve ring.

Screening for potential targets to reduce stenosis in bioprosthetic heart valves

Progressive stenosis is one of the main factors that limit the lifetime of bioprosthetic valved conduits. To improve long-term performance we aimed to identify targets that inhibit pannus formation on conduit walls. From 11 explanted, obstructed, RNAlater presevered pulmonary valved conduits, we dissected the thickened conduit wall and the thin leaflet to determine gene expression-profiles using ultra deep sequencing. Differential gene expression between pannus and leaflet provided the dataset that was screened for potential targets. Promising target candidates were immunohistologically stained to see protein abundance and the expressing cell type(s). While immunostainings for DDR2 and FGFR2 remained inconclusive, EGFR, ErbB4 and FLT4 were specifically expressed in a subset of tissue macrophages, a cell type known to regulate the initiation, maintenance, and resolution of tissue repair. Taken toghether, our data suggest EGFR, ErbB4 and FLT4 as potential target candidates to limit pannus formation in bioprosthestic replacement valves.

Four right ventricle to pulmonary artery conduit types

ObjectiveThe most durable valved right ventricle to pulmonary artery conduit for the repair of congenital heart defects in patients of different ages, sizes, and anatomic substrate remains uncertain. MethodsWe performed a retrospective analysis of 4 common right ventricle to pulmonary artery conduits used in a single institution over 30 years, using univariable and multivariable models of time-to-failure to analyze freedom from conduit dysfunction, reintervention, and replacement. ResultsBetween 1988 and 2018, 959 right ventricle to pulmonary artery conduits were implanted: 333 aortic homografts, 227 pulmonary homografts, 227 composite porcine valve conduits, and 172 bovine jugular vein conduits. Patients weighed 1.6 to 98.3 kg (median 15.3 kg), and median duration of follow-up was 11.4 years, with 505 (52.2%) conduits developing dysfunction, 165 (17.2%) requiring catheter intervention, and 415 (43.2%) being replaced. Greater patient weight, conduit z-score, type and position, as well as catheter intervention were predictors of freedom from replacement. Multivariable analysis demonstrated inferior durability for smaller composite porcine valve conduits, with excellent durability for larger diameter conduits of the same type. Bovine jugular vein conduit longevity was inferior to that of homografts in all but the smallest patients. Freedom from dysfunction at 8 years was 60.7% for aortic homografts, 72% for pulmonary homografts, 51.2% for composite porcine valve conduits, and 41.3% for bovine jugular vein conduits. Judicious oversizing of the conduit improved conduit durability in all patients, but to the greatest extent in patients weighing 5 to 20 kg. ConclusionsPulmonary and aortic homografts had greater durability than xenograft conduits, particularly in patients weighing 5 to 20 kg. Judicious oversizing was the most significant surgeon-modifiable factor affecting conduit longevity.

Replacement of the Mitral Valve Under One Year of Age: Size Matters.

Surgical management of mitral valve disease in neonates and infants is challenging. When repair is no longer feasible, replacement may become inevitable, but should only be considered as an option of last resort due to the remarkably high rate of associated morbidity and mortality. Mechanical valves are the preferred choice in large annuli, while stented conduits seem promising in smaller ones. In patients with a preoperative mitral valve annulus equal or larger than 15-16 mm, an intra-annular placement of the smallest mechanical valve available should be attempted. In patients with smaller annuli, the placement of a stented valved conduit seems to display a lower mortality risk. Supra-annular implantation of prostheses should be reserved for exceptional cases and to those familiar with this technique because of the high rate of associated complications.

Assessment of long-term outcomes: aortic valve reimplantation versus aortic valve and root replacement with biological valved conduit in aortic root aneurysm with tricuspid valve.

We compared the long-term outcomes between aortic valve reimplantation [David V (DV)] and aortic valve and root replacement with biological valved conduit [Bentall-De Bono (BD)] for the patients with aortic root aneurysm with tricuspid valve. Among 876 patients who underwent aortic root replacement in our institution between 2005 and 2018, 371 patients who underwent DV (n = 199) or BD (n = 172) for aortic root aneurysm with tricuspid valve were retrospectively reviewed. Exclusion criteria included aortic stenosis, infective endocarditis, previous prosthetic aortic valve, bicuspid aortic valve, aortic dissection and mechanical Bentall procedure. Propensity score matching was performed based on the patient characteristics, matching 90 patients in each group. The primary end point was all-cause mortality. Secondary end points were reoperation for any cause and specifically for aortic valve-related cause. After propensity score matching, DV and BD groups each had 1 in-hospital mortality (1.1%). Survival at 10 years was 95.3% [95% confidence interval (CI) 85.8-98.5] in DV and 98.6% (95% CI 90.8-99.8) in BD (P = 0.345). The cumulative incidences of reoperation at 10 years in DV versus BD were 3.9% (95% CI 0.7-11.8) vs 18.1% (95% CI 6.9-33.4) for any cause (P = 0.046) and 1.9% (95% CI 0.1-8.8) vs 15.9% (95% CI 5.5-31.4) for aortic valve-related causes (P = 0.032). The reasons for valve-related reoperation were aortic insufficiency (3/5 in DV vs 5/10 in BD), aortic stenosis (0/5 vs 2/10) and infective endocarditis (2/5 vs 3/10). Both DV and BD procedures for patients with aortic root aneurysm with tricuspid valve resulted in excellent 10-year survival. All-cause and aortic valve-related reoperations were significantly less frequent with valve-sparing root replacement, suggesting an advantage of DV over biological BD.

Abstract 14789: Multimodality Imaging in Mycobacterium Chimaera Cardiovascular Infections

Introduction: Mycobacterium Chimaera (MC) infections following cardiovascular surgery are challenging to diagnose given their insidious presentation. We therefore reviewed the various imaging modalities used to diagnose these infections at Mayo Clinic. Methods: Cases from 01/01/2010-06/01/2020 were identified using electronic medical records. Demographics and clinical history were collected. Imaging studies, including transthoracic echocardiogram (TTE), transesophageal echocardiogram (TEE), positron emission tomography / computed tomography (PET/CT), cardiac CT (CCT), and cardiac magnetic resonance (CMR) were reviewed. Results: A total of 7 patients (85.7% male) were found. 6 underwent aortic valve replacement and 1 received an aortic composite valve conduit. Surgical dates ranged from 01/2010-12/2018. Mean age at presentation was 63.3 years. Mean time from surgery to symptom onset was 28.0 months. All patients underwent TTE and TEE; prosthetic valve endocarditis was identified in 6 cases between both, while CMR established the diagnosis in 1 case. TTE showed prosthetic valve obstruction in 2 cases and an anterior pseudoaneurysm in 1 case. TEE findings included thickened prosthesis and/or vegetations (n=5), thickened posterior root (n=4), and root abscess (n=3). Among the 3 patients who underwent PET/CT, 2 demonstrated increased fluorodeoxyglucose (FDG) uptake around the aortic prosthesis; in addition, 1 had elevated FDG uptake in the myocardium suggesting myocarditis. 1 patient did not have aortic prosthesis FDG uptake. In the 2 patients who had CCT, 1 showed a pseudoaneurysm that prompted suspicion for endocarditis, and the other revealed a fluid collection adjacent to the aortic valve conduit. 2 patients underwent CMR; 1 had aortic prosthesis thickening and patchy areas of myocardial delayed enhancement suspicious for myocarditis, whereas the other showed vegetation and an aortic root abscess. Conclusion: TTE plus TEE successfully identified MC prosthetic valve endocarditis in most cases with TEE having higher specificity. Advanced imaging techniques are helpful to support the diagnosis and assess for myocardial and/or aortic involvement. Combining these modalities is therefore crucial in unveiling this elusive organism.

Abstract 14086: Early Results of a Novel EPTFE-based Pulmonary Valved Conduit in a Pediatric Patient Population

Introduction: This prospective, multicenter, single-arm, early feasibility study evaluates the safety and performance of an investigational ePTFE-based valve for replacement of the pulmonary valve and reconstruction of the Right Ventricular Outflow Tract. A novel polymeric pulmonary valved conduit, resistant to calcification and structural valve deterioration, may provide a more durable therapy option for the pediatric population by preventing loss of right ventricular function and increased freedom from valve-related reintervention and mortality. Methods: The primary endpoints at 6 months adjudicated by an independent Clinical Events Committee are valve-related mortality and device-related reintervention. The investigational device is a valved conduit comprised of ePTFE with stretch technology and a flexible tri-leaflet polymeric valve made of an advanced proprietary composite material, which can be tailored to length requirements of the anatomy. All enrolled patients met study inclusion/exclusion criteria and had a signed informed consent form. All patients had pre- and postoperative evaluation via transthoracic echocardiography (TTE). Aspirin was administered for a minimum of three months post procedure and, per institutional protocols, four patients were on temporary Coumadin. Results: Of the 17 patients enrolled from three sites, 52.9% were male. Ages ranged from 6 to 17 years (mean 11.5 ± 3.7). BSA ranged from 0.82 to 1.57 m 2 . At six months follow up, 100% of subjects successfully met the primary endpoint of freedom from valve-related mortality and device-related reintervention. No patient exhibited an RVOT gradient &gt; 20 mmHg. No patients had pulmonary regurgitation above baseline (≤ mild) observed through six months. Throughout postoperative serial TTE evaluation at discharge, 1, 3, and 6 months, no evidence of worsening valvular insufficiency was observed. No patient developed endocarditis and TTE detected no clinically significant thrombus formation. Conclusions: These preliminary data of a novel Pulmonary Valve Conduit suggest improved pulmonic and right ventricular function based on TTE measurements, no unexpected findings, no valve-related adverse events and encouraging hemodynamic performance through 6 months.

Successful transcatheter aortic valve implantation in a patient after an apico-aortic conduit for severe aortic stenosis complicated by haemolytic anaemia: a case report.

BackgroundApico-aortic conduit (AAC) which connects the left ventricular (LV) apex directly to the descending aorta through a valved conduit, is an alternative to surgical aortic valve replacement (AVR) for patients with aortic stenosis (AS) who are inoperable or high risk for surgical AVR and are not suitable candidates for transcatheter aortic valve implantation (TAVI).Case summaryAn 84-year-old man with severe AS underwent an AAC combined with coronary artery bypass grafting 8 years earlier. A saphenous vein graft was anastomosed from the conduit to the left anterior descending artery. He had developed haemolytic anaemia requiring frequent blood transfusions. The stenosis at the anastomosis of the left ventricle and the conduit might be the cause of a turbulent flow and a shear stress which led to mechanical haemolysis. We expected that dilatation of native aortic valve would reduce the blood flow at the anastomosis site and thereby improve haemolytic anaemia. Since balloon aortic valvuloplasty improved haemolytic anaemia without exacerbation of myocardial ischaemia, transsubclavian TAVI was performed. After the TAVI, significant reductions in the pressure gradient between the left ventricle and the ascending aorta and that between the left ventricle and the conduit were achieved, and the patient remained clinically stable without the recurrence of haemolytic anaemia.DiscussionThis is the first report regarding mechanical haemolytic anaemia after AAC which might result from a turbulence and a shear stress by the stenosis of the anastomosis of the LV apex and the conduit. A careful monitoring for conduit dysfunction should be made after AAC.

Emergency aortic root replacement with the Bioconduit stentless aortic valve conduit

This report concerns a 73-year-old woman who presented with asymptomatic aortic root an-eurysm with severe aortic regurgitation. The purpose of this article is to present our first successful case for emergency aortic root replacement (Bentall operation) that involves annular implantation of a pericardial valved conduit (Bioconduit TM, Biointegral Surgical, Inc., Ontario, Canada) and to discuss some essential technical clue issues related to this approach.

The early results of pulmonary autograft mitral valve replacement (Ross Ⅱ) in infants

Objective: To evaluate the early results of pulmonary autograft mitral valve replacement (Ross Ⅱ procedure) in infants with intractable congenital mitral valve lesions. Methods: Between August 2018 and September 2019, 6 infants underwent mitral valve replacement with a pulmonary autograft in Department of Cardiovascular Surgery, Guangzhou Women and Children's Medical Center. There were 2 males and 4 females.The age at surgery ranged from 50 days to 1 year old.Preoperative diagnoses included severe to critic mitral valve insuffiency in all patients, moderate mitral valve stenosis in 3 patients, and mitral valve prolapse in one. When the pulmonary autograft was harvested, a cuff of bovine or autologous pericardium was sewn onto the proximal (infundibular) end of the autograft ( "top-hat" configuration). The distal (pulmonary) end of the autograft was secured to the mitral annulus.At the level of the left atrial free wall, the pericardial cuff was progressively tailored and sewn onto the atrial wall to remain away from the ostia of the pulmonary veins and to maintain normal morphology of the autograft. The bovine jugular valved conduit was used to reconstruct the right ventricular outflow tract. Results: There was one early death due to sudden cardiac arrest at the night of surgery day. The remaining 5 patients were successfully recovered and discharged. Follow-up of survivors ranged from 3 to 13 months. Echocardiographic follow-up demonstrated the flow velocity across the mitral valve position was 1.5 to 2.3 m/s, with a means gradient of 4 to 6 mmHg (1 mmHg=0.133 kPa). Four patients showed mild mitral insuffiency, normal left atrium and ventricle size and left ventricle ejection fraction.One patient had moderate mitral insuffiency, pulmonary valve endocarditis, and reduced left ventricle ejection fraction. The clinical symptoms of all survivals improved significantly and the weight gain were satisfactory. Conclusion: Pulmonary autograft mitral valve replacement may be a feasible and effective remedial surgical strategy for young infants with intractable congenital mitral valve lesions.

Management of the aortic root in type A aortic dissection: A valve sparing approach.

Type A acute aortic dissection (TAAAD) is rapidly fatal without emergency repair. Surgical outcomes have improved over the years with improvements in technique and postoperative care. Classically, supracomissural aortic replacement has been the standard of care. However, reintervention rates, particularly on the aortic root in certain groups of patients, shifted the focus towards improving long-term results of surgical repair. With regard to the aortic root, root replacement has been the gold standard. However, the surgical community realized that valve replacement in itself is a disease, and valve sparing aortic root replacement (VSRR) took center stage in the care of these patients. We searched the Pubmed and EMBASE databases for articles related to VSRR and composite valve conduit (CVC) root replacement, and the long-term results of these techniques in TAAAD. Supracomissural repair is limited by reintervention, and CVC results are affected by complications related to the prosthetic valve. Conversely, VSRR is associated with good short-term outcomes, improvement in quality of life, and it is durable. VSRR is a sound technique in TAAAD in experienced hands.

Comparative Effectiveness of Mechanical Valves and Homografts in Complex Aortic Endocarditis

The ideal surgical reconstruction of the aortic root in patients with complex endocarditis is controversial. We compared the short- and long-term outcomes between mechanical valves, bioprostheses, and homografts. We identified all patients undergoing an operation for active complex aortic endocarditis at our institution between 2003 and 2017. We grouped patients according to those who received a mechanical valve, bioprosthesis, or homograft. We used multiple logistic regression and proportional hazards models. To minimize confounding by indication, we used marginal risk adjustment to simulate that every patient would undergo (contrary to fact) all 3 operations. Of 159 patients with complex active endocarditis, 48 (30.2%) had a valve plus patch reconstruction, and 85 (53.4%) had a root replacement. Of all, 50 (31.5%) had a mechanical valve, 56 (35.2%) had a bioprosthesis, and 53 (33.3%) had a homograft. The groups were similar in age, sex, body mass index, comorbid conditions, organism, abscess location, and mitral involvement (all P > .05). However, patients receiving mechanical reconstructions were more likely to have native valve endocarditis (46% vs 37.5% vs 17%; P= .005) and less likely to undergo root replacement (32% vs 28.6% vs 100%; P < .001). Marginal risk-adjusted operative mortality was lowest for mechanical valves (4.8%) and highest for homografts (16.9%; P= .041). Long-term survival after root replacement was worse with homografts than with mechanical valve conduits (adjusted hazard ratio, 2.9; P= .045). In patients with complex endocarditis, mechanical valves are associated with similar, if not better, short- and long-term outcomes compared with homografts, even after adjusting for important baseline characteristics and limiting the analysis to root replacements only.

Right ventricular outflow reconstruction with handmade valve conduit - A short experience from a developing country. Case series

ObjectivesRight ventricular outflow tract continuity abnormalities are one of the most commonly encountered entities in the field of congenital cardiac surgery. Various strategies including homograft, valve conduit, Contegra are used to restore continuity between right ventricle and pulmonary artery. In countries like Pakistan these may not be easily available and affordable. We report the experience of our short observational study of using a handmade trileaflet valve conduit to reconstruct the right ventricular outflow tract. MethodologyFrom September 2015 to December 2016, a total of 15 patients with different congenital heart diseases underwent open-heart surgery at our institute. Restoration of right ventricular to pulmonary artery continuity was achieved using handmade valve conduit utilizing bovine pericardium and thin sheet PTFE sheets (0.1 mm) as conduit and valve respectively. ResultsPatients ranged from 1 to 16 years. Seven patients had previous palliation including 4 blalock taussig (BT) Shunts and 3 pulmonary artery (PA) banding. Postoperative complications were observed in 4 patient including 2 in hospital deaths and 2 required interventions. One patient developed aneurysm at RV- conduit junction requiring surgical repair and the other underwent conduit dilatation for moderate to severe stenosis (gradient 60 mmHg). No significant regurgitation was observed in this series. Overall postoperative gradients were stable with mean gradient 25.3 mmHg (8 mmhg - 60 mmHg). ConclusionThe use of handmade valve conduits has acceptable morbidity and mortality. These are cost effective alternatives in this part of the world, where well-established conduits have cost implications and uncertain availability.