To Compare the Effects of a Standard Versus Hydrophilic Polymer Coated Airway Stent in a Porcine Model: A Randomized, Single-Blinded Study.

BACKGROUND: Stent encrustation with debris and mucostasis is a significant cause of airway injury and comorbidity, leading to ~25% of stent exchanges (1-3). Previous work from our group has shown that the experimental coating can reduce mucous adhesion in bench testing and demonstrated a signal for reducing airway injury and mucostasis in a feasibility study. OBJECTIVES: The aim of this study is to continue our inquiry in a randomized, single-blinded multi-animal trial to investigate the degree of airway injury and mucostasis using silicone stents with and without this specialized coating. METHODS: We modified commercially available silicone stents with a hydrophilic polymer from Toray Industries. We conducted an in vivo survival study in 6 mainstem airways (3 coated and 3 uncoated) of 3 pigs to compare the degree of airway injury and mucostasis between coated versus noncoated stented airways. Both stents were randomized to either left or right mainstem bronchus. The pathologist was blinded to the stent type. RESULTS: We implanted a total of six 14×15 mm silicone stents (1 per mainstem bronchi) into 3 pigs. All animals survived to termination at 4 weeks. All stents were intact; however, 1 uncoated stent migrated out. On average, all the coated stents demonstrated reduced pathology and tissue injury scores (75 vs. 68.3, respectively). The average total dried mucous weight was slightly higher in the coated stents (0.07 g vs. 0.05 g; respectively). CONCLUSION: Coated stents had lower airway injury compared with uncoated stents in this study. Of all the stents, 1 uncoated stent migrated out and was not included in the dried mucous weight totals. This could explain the slightly higher mucous weight in the coated stents. Nevertheless, this current study demonstrates promising results in lowering airway injury in stents incorporated with the hydrophilic coating, and future studies, including a larger number of subjects, would be needed to corroborate our findings.

Infant Mitral Valve Replacement: Current State of the Art.

Mitral valve replacement (MVR) in the very young is an imposing clinical challenge. Early and late mortality risk is substantial, severe adverse events are common, and redo mitral valve replacement is inevitable. Therapeutic options are limited. In the older infant with an annulus of 17mm or larger, mechanical MVR is associated with low risk of mortality and predictable durability. For the very young with annular hypoplasia, bovine jugular vein conduit MVR appears to offer equivalent or better early outcomes with the possibility of subsequent valve expansion, potentially prolonging the interval to redo MVR. Experience with cylinder MVR and other forms of surgeon-manufactured MVR is quite limited, and there is currently no information on late outcomes or durability.

Fetal Unguarded Mitral Valve Orifice, Aortic Atresia, and Severe Left Heart Enlargement.

Unguarded mitral valve orifice is a rare disease with only 7 described cases in the literature. We describe the first known case of unguarded mitral valve orifice with normal segmental cardiac anatomy, severe left ventricular dilatation and dysfunction, aortic atresia, and atrial flutter. (Level of Difficulty: Advanced.).

Vascular grafts and valves that animate, made from decellularized biologically-engineered tissue tubes.

Biologically-engineered matrix - a tissue that is grown in vitro from donor cells, decellularized, and stored prior to use as off-the-shelf allografts - offers a promising alternative to current cardiovascular biomaterials. This perspective reviews preclinical studies and clinical trials of vascular grafts and valves comprising biologically-engineered matrix, with a focus on those based on donor dermal fibroblast remodeling of fibrin gel with the capacity to heal and grow following recellularization, via animation of the matrix. It concludes with a discussion of related key clinical considerations.

Feasibility of intraoperative aortic root imaging in congenital heart surgery.

BACKGROUND: Intraoperative vascular imaging is a useful tool to evaluate coronary ostia in congenital heart patients with suboptimal preoperative imaging findings. Additionally, vascular imaging has potential value for visualization of the ascending aortic intima media thickness (IMT) in certain clinical scenarios. This study sought to evaluate the feasibility of intraoperative vascular imaging of coronary ostia and IMT during congenital heart surgery. METHODS: We describe the technique for performance of intraoperative vascular imaging by a pediatric cardiologist using a high-resolution linear sequential array transducer. RESULTS: Intraoperative vascular imaging was obtained on seven patients. Coronary ostia were normal in all except one. This patient had congenital stenosis of the left coronary ostium discovered during intraoperative imaging and confirmed by the surgeon. In another patient with Williams syndrome, the IMT was noted to be prominent. CONCLUSIONS: It is feasible to perform intraoperative vascular imaging in less than 5 minutes of operator's time and provides superior visualization of the coronary ostia and IMT.

Magnetic Resonance Imaging Based Flow Field and Lagrangian Particle Tracking From a Left Ventricular Assist Device.

This study explores the optimal left ventricular assist device (LVAD) cannula outflow configuration in a patient-specific replica of the aorta. The volumetric velocity field is measured using phase-contrast magnetic resonance imaging (PC-MRI) under a physiologically relevant steady flow. The effect of the LVAD outflow graft insertion site and anastomosis angle on the transport of embolic particles to cranial vessels is studied by solving the particle equation of motion for spheres in the range of 0.1-1.0 mm using the measured three-dimensional (3D) velocity field. Results show that for a given aorta anatomy, it is possible to design the cannula graft location and terminal curvature so that the probability of embolic transport to the cranial vessels is significantly minimized. This is particularly important since the complex flow pattern in each cannula case affects the embolic trajectories differently, and hence the common assumption that particles distribute by the volumetric flow division does not hold.

The First Repair of Cor Triatriatum.

This article describes the first patient treated surgically for cor triatriatum, and also describes preoperative testing, operative findings, and procedures, as well as follow-up.

Neonatal pulmonary artery reconstruction during shunting to treat and prevent juxtaductal coarctation.

BACKGROUND: Coarctation of the pulmonary artery may lead to its early obstruction. We investigated the outcomes of a strategy of aggressive reconstruction of the pulmonary arteries in the neonatal period. METHODS: From 2000 to 2013 a total of 162 consecutive neonates (< 90 days) underwent systemic-to-pulmonary shunting. Twenty-eight of them underwent the following concomitant reconstruction of the central pulmonary arteries: end-to-end anastomosis (4), patch reconstruction of the pulmonary arteries (24) with 0.4 mm Gore-Tex (W. L. Gore & Associates, Newark, DE) patch (18), or autologous pericardium (6). Ten patients were directed to univentricular palliation and 18 to biventricular repair. RESULTS: There was 1 in-hospital death (4%) and 2 deaths after hospital discharge (inter-stage mortality, 7%). The follow-up of the 25 survivors was complete. After a mean of 3 ± 3 years, patients with single ventricle palliation reached the following stages: shunts (2); one and a half ventricle repair (1); bidirectional cavopulmonary shunt (4); and Fontan (2). Fourteen of the patients destined for biventricular physiology reached complete repair while 2 patients were still with shunts. There was no pulmonary artery occlusion. Focal narrowing or pulmonary artery hypoplasia was the main indication for 10 of the subsequent 36 reinterventions. CONCLUSIONS: Neonatal pulmonary artery reconstruction effectively prevents pulmonary artery occlusion and warrants pulmonary artery growth in the majority of cases of juxtaductal pulmonary artery coarctation. A number of these patients needed enlargement of their central pulmonary arteries in subsequent procedures. Indications of this reconstruction at the time of systemic-to-pulmonary shunting remains to be specified.

Downsized Contegra graft as a right ventricle-to-pulmonary artery conduit in the setting of mediastinitis.

Polytetrafluoroethylene (PTFE) grafts are commonly used for construction of the right ventricle-to-pulmonary artery conduit in the modified Norwood procedure. Dehiscence of a PTFE conduit in the setting of purulent mediastinitis presents a challenging clinical problem because of limited availability of appropriately sized replacement vascular homografts. The Contegra bovine jugular vein graft is an alternative to placing another PTFE graft in an infected space when a homograft of appropriate size is not available. We describe the use of a downsized Contegra conduit to replace an infected PTFE right ventricle-to-pulmonary artery graft in a neonate with life-threatening purulent mediastinitis.

The 2010 Thoracic Surgery Residents Association workforce survey report: a view from the trenches.

BACKGROUND: Workforce estimates suggest 11% of general surgery residents are considering careers in cardiothoracic (CT) surgery. In an effort to identify areas for programmatic improvement, we examined trends in thoracic surgery residents' perspectives on training and employment. METHODS: Results from the 2010 Thoracic Surgery Residents Association workforce survey were analyzed. The survey was administered to all trainees in North America during the annual in-service exam. Longitudinal trends from 2006 to 2010 are reported. RESULTS: Of 299 respondents, 76% (228 of 299) were US citizens. The most common determinants in choosing CT surgery were types of cases (123 of 299, 41%) and mentorship (95 of 299, 32%). Sixty-five percent (193 of 299) would recommend CT surgery to potential trainees. While 81% (242 of 299) felt they would be adequately trained in their program, 39% (118 of 299) planned additional fellowship training. Only 23% (70 of 299) felt the 80-hour work week had a positive impact on training. Of residents seeking jobs, 68% (62 of 92) received 2 or more job interviews and 70% (69 of 99) more than 1 job offer. Seventeen percent (16 of 92) had no offers. While 45% (51 of 114) reported still searching for employment, 20% (23 of 114) had accepted private practice positions, 25% (29 of 114) academic positions, and 6% (7 of 114) fellowship positions. Education-related debt was greater than $100,000 in 46% (140 of 299) and greater than $200,000 in 17% (52 of 299). From 2007 to 2010, CT residents reporting debt greater than $200,000 rose from 8% to 17%. Accepted fellowship training positions dropped to 6% in 2010 compared with 13% and 15% in 2008 and 2009, respectively. CONCLUSIONS: Diminished CT job opportunities remain a concern. There are concerning trends in debt accrual and perceptions of work-hour restrictions on quality of training. These data justify further investigation into areas of improvement in CT training.

Mucosal tube technique for creation of esophageal anastomosis after esophagectomy.

BACKGROUND: The definitive treatment of esophageal cancer remains surgical resection. Morbidity and mortality are highly influenced by the success of the anastomosis created in the reconstruction of the resected esophagus. The results of an anastomotic technique that creates an esophageal mucosal tube are analyzed. METHODS: The medical records of all patients undergoing esophagectomy at a single institution by 3 surgeons between January 2002 and July 2008 were reviewed. Patients who underwent a 2-layer, hand-sewn, esophageal anastomosis using a mucosal tube were included. The unique aspect of the anastomosis was the creation of an esophageal mucosal tube that facilitates a tension-free, precise mucosal approximation. RESULTS: Of the 61 patients who underwent esophageal reconstructions (60 gastric, 1 colonic), 49 (80%) had a diagnosis of esophageal neoplasm. Of those with cancer, 20 (41%) had neoadjuvant therapy before the resection. Two patients presented with perforation. The anastomoses were intrathoracic in 57 of 61 (93%) and cervical in 4 cervical. There were no operative deaths. All patients underwent contrast study at an average of 5 days postoperatively. The anastomotic leak rate was 2% (1 of 61). Postoperative dilations (mean, 1.3 dilations) were done in 12 of 61 patients (20%), using a low symptom threshold for endoscopy and dilation. CONCLUSIONS: The use of the esophageal mucosal tube and 2-layer anastomosis is a robust technique that results in a low leak rate. Strictures are minimal and easily dilated if they occur. Use of a gastrotomy larger than 2.5 cm may decrease stricture rates.

Results with continuous cardiopulmonary bypass for the bidirectional cavopulmonary anastomosis.

OBJECTIVE: Some centres have proposed creating the bidirectional cavopulmonary anastomosis without cardiopulmonary bypass, while others continue to use deep hypothermic circulatory arrest. The purpose of this review is to evaluate the results of using continuous cardiopulmonary bypass with moderate hypothermia, perhaps the most commonly used of the three techniques for this procedure. METHODS: Between 1990 and 2005, 114 patients, having a mean age of 1.58 years, with a median age of 8 months, and ranging from 3 months to 16 years, underwent creation of either a unilateral cavopulmonary anastomosis, in 94 cases, or bilateral anastomoses in 20 cases. All had continuous cardiopulmonary bypass with moderate hypothermia at 32 degrees Celsius, with 24 also having aortic cross-clamping with cardioplegia for simultaneous intracardiac procedures. Interrupted absorbable sutures were used to create the anastomosis in 105 patients. RESULTS: Perioperative mortality was 5%, with 6 of the patients dying. The mean period of cardiopulmonary bypass for an isolated anastomosis was 91 minutes, with a range from 44 to 160 minutes. In 10 patients (8.8%), it was necessary to place a graft to augment the anastomosis. The average postoperative length of stay was 7.9 days for those undergoing an isolated unilateral anastomosis, and 16.4 days for patients undergoing combined cardiac operations. We have now created the Fontan circulation in 79 of the patients, at an average interval from the bidirectional cavopulmonary anastomosis of 2.1 plus or minus 1.14 years. In 76 patients, we performed postoperative angiograms, and none revealed any stenoses. CONCLUSIONS: The bidirectional cavopulmonary anastomosis can be performed successfully with continuous cardiopulmonary bypass and moderate hypothermia with a beating heart, avoiding circulatory arrest. The use of interrupted and absorbable sutures was not associated with any late anastomotic stenosis.

Topical application of bacitracin ointment is associated with decreased risk of mediastinitis after median sternotomy.

BACKGROUND: The diagnosis of mediastinitis after open-heart surgery is infrequent but dreaded as it carries a high morbidity and mortality. The purpose of this study was to investigate the impact that topical antibacterials would have on the postoperative mediastinitis rate. METHODS: Data were collected from 2455 consecutive patients who underwent sternotomy and cardiopulmonary bypass for both valvar and ischemic heart disease. Prior to 1999, patients (n = 1036) underwent surgery with standard perioperative intravenous antibiotics but no application of bacitracin. After 1999, patients (n = 1419) underwent surgery with intravenous antibiotics and application of bacitracin ointment to the sternotomy incision after closure. RESULTS: Cases of mediastinitis occurred in 12 patients (1.2%) not treated with bacitracin, which required re-exploration, sternectomy, and soft tissue closure of the mediastinum. Alternatively, 3 patients (0.2%) in the group treated with bacitracin developed mediastinitis (P < .01). Therefore, the use of topical antibacterials was associated with a 6-fold reduction in the risk of mediastinitis after cardiac surgery. This significant difference in the infection rate was observed even though the percentage of patients with risk factors for mediastinitis was equal to greater than the group not treated with bacitracin. Non-bacitracin versus bacitracin: diabetics, 298 versus 484; emergency operations, 24 versus 50; bilateral internal thoracic grafts, 28 versus 29; and obesity (body mass index >30), 294 versus 396. CONCLUSIONS: The use of topical antibacterials is associated with a decrease in the risk of mediastinitis after cardiac surgery.

Paravalvular leaks around prosthetic valves implanted in the mitral position: technical refinements of the ovine model.

BACKGROUND AND AIM OF THE STUDY: Currently, the sheep model is preferred for preclinical in-vivo evaluation of prosthetic heart valves implanted in the mitral position. In sheep, the anatomy and tissue characteristics in, and around, the native mitral valve's posterior commissure (12:00-3:00 quadrant) makes valve implantation technically challenging. As the majority of non-infectious paravalvular leaks occurred in this quadrant, the surgical technique was modified to offer greater exposure of the annulus in this region and permit more accurate placement of sutures. METHODS: A total of 223 valve implantations (138 bioprostheses, 85 mechanical valves) performed between 1991 and 1998 using the sheep model was retrospectively reviewed. No evidence of endocarditis was found, indicating that etiology of the leaks was due to surgical technique. The incidence of paravalvular leak in the 12:00-3:00 quadrant was compared with that in all other quadrants, both before and after the surgical technique change. RESULTS: The incidence of paravalvular leak was 33% (28/85) for mechanical valves and 13.8% (19/138) for bioprosthetic valves. Leaks in the 12:00-3:00 quadrant accounted for 82% (14/17) of those occurring before the surgery change, and only 43% (13/30) afterwards. Before the change, the incidence of paravalvular leak was 20.3% (14/69) in the 12:00-3:00 position, and 4.3% (3/69) in the non-12:00-3:00 quadrants. After the change, incidence in the 12:00-3:00 position fell to 8.4% (13/154; p < 0.05), but that in other quadrants was not significantly affected. Analysis by valve type showed that leak incidence in the 12:00-3:00 quadrant fell from 20.3% (12/59) to 3.8% (3/79) in the bioprosthesis group (p < 0.05), and from 20.0% (2/10) to 13.3% (10/75) in the mechanical valve group (p = 0.56). In all other quadrants there was no statistically significant change in either groups. CONCLUSION: Technical refinement of surgery has led to a reduced incidence of paravalvular leak in the 12:00-3:00 quadrant, thereby providing a standard by which to compare prostheses implanted in the mitral position. These data should also assist in improving prosthetic heart valve design by enabling device-related complications to be distinguished from model-related complications.