Xun Zhou

Tissue engineered vascular grafts: current state of the field

ABSTRACT Introduction: Conventional synthetic vascular grafts are limited by the inability to remodel, as well as issues of patency at smaller diameters. Tissue-engineered vascular grafts (TEVGs), constructed from biologically active cells and biodegradable scaffolds have the potential to overcome these limitations, and provide growth capacity and self-repair. Areas covered: This article outlines the TEVG design, biodegradable scaffolds, TEVG fabrication methods, cell seeding, drug delivery, strategies to reduce wait times, clinical trials, as well as a 5-year view with expert commentary. Expert commentary: TEVG technology has progressed significantly with advances in scaffold material and design, graft design, cell seeding and drug delivery. Strategies have been put in place to reduce wait times and improve ‘off-the-shelf’ capability of TEVGs. More recently, clinical trials have been conducted to investigate the clinical applications of TEVGs.

Pseudoaneurysm formation after valve sparing root replacement in children with Loeys-Dietz syndrome

Loeys‐Dietz syndrome (LDS) is an autosomal dominant connective tissue disorder predisposing patients to aneurysm formation and arterial dissection. Aortic root replacement is often performed prophylactically and valve‐sparing root replacement (VSRR) has become the procedure of choice. However, in these patients with connective tissue disorders, postoperative pseudoaneurysms may develop.

In vivo therapeutic applications of cell spheroids

Spheroids are increasingly being employed to answer a wide range of clinical and biomedical inquiries ranging from pharmacology to disease pathophysiology, with the ultimate goal of using spheroids for tissue engineering and regeneration. When compared to traditional two-dimensional cell culture, spheroids have the advantage of better replicating the 3D extracellular microenvironment and its associated growth factors and signaling cascades. As knowledge about the preparation and maintenance of spheroids has improved, there has been a plethora of translational experiments investigating in vivo implantation of spheroids into various animal models studying tissue regeneration. We review methods for spheroid delivery and how they have been utilized in tissue engineering experiments. We break down efforts in this field by organ systems, discussing applications of spheroids to various animal models of disease processes and their potential clinical implications. These breakthroughs have been made possible by advancements in spheroid formation, in vivo delivery and assessment. There is unexplored potential and room for further research and development in spheroid-based tissue engineering approaches. Regenerative medicine and other clinical applications ensure this exciting area of research remains relevant for patient care.

Off-pump coronary artery bypass in octogenarians: results of a statewide, matched comparison

ObjectivesOff-pump coronary artery bypass grafting (OPCAB) may have advantages in the elderly. Although proven safe, it remains unclear whether OPCAB provides a short-term survival benefit in octogenarians. We sought to compare outcomes using propensity matching between OPCAB and conventional surgery in a statewide database.MethodsWe identified all octogenarians (≥u200980xa0years) who underwent isolated coronary artery bypass grafting (CAB) at 10 different centers in the state of Maryland from July 2011 to June 2016. We separated patients into two groups: OPCAB and on-pump coronary artery bypass (ONCAB). Patients were assigned propensity scores with a semi-parsimonious logistic regression model and matched 1:1 by the nearest-neighbor principle. A revascularization ratio was determined between the number of distal grafts sewn and number of diseased coronaries (≥u200950% stenosis).ResultsIn total, 926 octogenarians underwent isolated CAB (8.2% of all CAB): 798 (86%) had ONCAB and 128 (14%) had OPCAB. Propensity matching yielded 128 well-matched pairs. Operative mortality was similar between groups (OPCAB 5.5% vs ONCAB 3.1%, pu2009=u20090.364). Rates of complications were similar between groups. OPCAB patients had a lower revascularization ratio (0.92 vs 1.15, pu2009<u20090.001), but more frequent use of left internal mammary artery (97 vs 89%, pu2009=u20090.017), and decreased intraoperative transfusion rates (33 vs 63%, pu2009<u20090.001).ConclusionsIn comparing outcomes among octogenarians across the state of Maryland, OPCAB and ONCAB had similar mortality and morbidity. However, OPCAB was associated with a lower revascularization ratio. Thus, our results demonstrate no short-term survival benefit of OPCAB over ONCAB in octogenarians.

Coronary Button Pseudoaneurysms After Aortic Root Replacement in a Child With Loeys-Deitz Syndrome

Loeys-Deitz syndrome (LDS) is a connective tissue disorder characterized by aggressive aortopathy with a proclivity for aortic aneurysmal rupture and dissection. Prophylactic surgical intervention is often indicated to ameliorate risk of aneurysm rupture. Aortic root replacement involves excision of the coronary arteries from the aortic root with a button of surrounding aortic tissue and subsequent anastomosis of these buttons to the synthetic aortic graft. We report the case of a 16-year-old girl with LDS who developed pseudoaneurysms at the sites of previous coronary button implantation.

Tricuspid Valve Detachment in Ventricular Septal Defect Closure Does Not Impact Valve Function

BACKGROUNDnAlthough tricuspid valve detachment (TVD) facilitates improved exposure during transatrial ventricular septal defect (VSD) closure, few have analyzed the impact of TVD on long-term valve durability.nnnMETHODSnPediatric patients undergoing VSD closure at our institution from 1997 to 2013 were identified, and charts were retrospectively reviewed. Patients were separated into groups based on utilization of TVD. Propensity score matching was then performed using a nonparsimonious logistic regression model involving 7 variables. Primary outcome was residual TV dysfunction at long-term follow-up, defined as mild (2+) and moderate (3+) TV regurgitation (TR) on follow-up echocardiography. Secondary outcomes included postoperative atrioventricular dissociation, residual VSD, and reinterventions.nnnRESULTSnA total of 247 patients underwent VSD closure; 164 (66.4%) without TVD and 83 (33.6%) with TVD. Median follow-up time was 2,343 days (interquartile range, 1,237 to 3,963.5 days) in the group without TVD versus 1,606 days (interquartile range, 826 to 3,017 days) in those with TVD. After successfully matching 83 patients, 29 of 83 (34.9%) patients in the non-TVD group had mild TR versus 28 of 83 (33.7%) patients in the TVD group (pxa0= 0.87). 2 patients in the non-TVD group had moderate TR versus 1 patient in the TVD group at long-term follow-up. One patient in each group suffered transient atrioventricular block, but neither required pacemaker insertion.nnnCONCLUSIONSnTVD did not compromise long-term valve durability and did not impose increased morbidity. Patients who underwent TVD had a similar prevalence of mild TR to patients without TVD. Moderate TR was exceptionally rare in both groups. When exposure is difficult, TVD is a safe and effective technical adjunct.

The Prevalence and Impact of Congenital Diaphragmatic Hernia among Patients Undergoing Surgery for Congenital Heart Disease

There has not been a multicenter investigation to elucidate the prevalence and impact of congenital diaphragmatic hernia (CDH) on children undergoing cardiac surgery. We investigated the prevalence of CDH across congenital cardiac diagnostic and procedural groups and its impact on outcomes. The STS Congenital Heart Surgery Database was queried to identify children undergoing cardiac surgery who also had CDH. Baseline perioperative characteristics and postoperative outcomes were compared between groups. Subgroup analyses were performed based on case complexity as determined by STAT Categories. Overall 426 of 157,419 (0.27%) pediatric patients undergoing an index cardiac operation had a diagnosis of CDH including 89 neonates (0.25% of all neonatal index operations), 217 infants (0.39%), and 120 children (0.18%). The frequency of concomitant CDH varied across diagnostic groups and, in neonates and infants, was highest for tetralogy of Fallot (0.45%, nu202f=u202f41), coarctation (0.39%, nu202f=u202f27) and complete atrioventricular septal defects (0.31%, nu202f=u202f19). For neonates and infants outcomes were generally worse in CDH vs no-CDH patients across the various procedural strata. For example, STAT ≥3 operative mortality was 34.4% vs 10.3% ( P < 0.001) for neonates, and 24.2% vs 5.3% ( P < 0.001) for infants with vs without CDH, respectively. In older children, outcomes disparities were less clear cut with no significant differences in mortality, and variable differences for complication and length of stay outcomes. CDH occurs in a small percentage of patients born with congenital heart disease. Concomitant diagnosis of CDH portends increased morbidity and mortality in infants and neonates undergoing cardiac surgery.