Total aortic arch replacement using a frozen elephant trunk device: Results of a 1-year US multicenter trial.

OBJECTIVE: In this prospective US investigational device exemption trial, we assessed the safety and 1-year clinical outcomes of the Thoraflex Hybrid device (Terumo Aortic) for the frozen elephant trunk technique to repair the ascending aorta, aortic arch, and descending thoracic aorta. METHODS: For the trial, which involved 12 US sites, 65 patients without rupture were recruited into the primary study group, and 9 patients were recruited into the rupture group. All patients underwent open surgical repair of the ascending aorta, aortic arch, and descending thoracic aorta in cases of aneurysm and/or dissection. The primary end point was freedom from major adverse events (MAE), defined as permanent stroke, permanent paraplegia/paraparesis, unanticipated aortic-related reoperation (excluding reoperation for bleeding), or all-cause mortality. RESULTS: In the primary study group, 2 patients were lost to follow-up at 1 year. Freedom from MAE at 1 year was 81% (51/63). Seven patients (11%) died (including 2 before 30 days or discharge), 3 patients (5%) suffered permanent stroke, and 3 (5%) developed permanent paraplegia/paraparesis. Twenty-six patients (41%) underwent planned extension procedures, including 22 endovascular procedures within a median of 122 (interquartile range, 64-156) days. In the aortic rupture group, 2 patients were lost to follow-up at 1 year. Freedom from MAE at 1 year was 71% (5/7). One patient (14%) died, 2 patients (29%) had permanent stroke, and none had permanent paraplegia/paraparesis. No extension procedures were performed in the rupture group. CONCLUSIONS: One-year results with the Thoraflex Hybrid device are acceptable. Long-term data are necessary to assess the durability of these repairs.

Attempt at off-label balloon valvuloplasty post-dilation for intuity sutureless valve.

Alternatives to traditional aortic valve replacement now form part of the valve surgeon's armamentarium. Sutureless valves offer decreased bypass and crossclamp times, excellent maneuverability, and promising outcomes. We present a case of a sutureless aortic valve replacement for a late failed David procedure, complicated by postoperative development of severe paravalvular regurgitation. We attempted off-label balloon post-dilation to improve expansion of the valve, however paravalvular regurgitation persisted. The patient underwent subsequent aortic valve replacement using a mechanical valve and experienced no further paravalvular leak.

Total body irradiation in Australia and New Zealand: results of a practice survey.

Total body irradiation (TBI) is an important treatment modality for the preparation of patients for bone marrow transplants. It is technically challenging and the actual delivery may vary from clinic to clinic. Knowledge of the pattern of practice may be helpful for clinics to determine future practice. We carried out an email survey from April to September 2019 sending 48 TBI related questions to all radiotherapy clinics in Australia and New Zealand via the Australasian College of Physical Scientists in Medicine email distribution list. Centres not performing TBI were not expected to complete the survey and centres that had participated in a previous survey, or that were known to perform the treatment, were followed up if no response was received. Of a total of approximately 70 centres, 14 clinics responded to the survey. The vast majority of clinics use conventional lateral and/or anterior-posterior beams at extended SSD for TBI treatment delivery. However, treatment planning, ancillary equipment (used for immobilisation/modulation), beam energy and prescribed lung doses vary considerably-with some clinics delivering the prescription dose to the lungs and some aiming to deliver a lung dose which is lower than the prescription dose. Only one clinic reported using an advanced delivery technique with modulated arcs at extended SSD. Centres either said they had no access to outcome data or did not answer this question. Compared with an earlier survey from 2005, 3 clinics have lowered their linac dose rate and 7 are the same or similar. The TBI practice in Australia and New Zealand remains varied, with considerable differences in treatment planning, beam energy, accepted lung doses and delivered dose rates.

CD90 Identifies Adventitial Mesenchymal Progenitor Cells in Adult Human Medium- and Large-Sized Arteries.

Mesenchymal stem cells (MSCs) reportedly exist in a vascular niche occupying the outer adventitial layer. However, these cells have not been well characterized in vivo in medium- and large-sized arteries in humans, and their potential pathological role is unknown. To address this, healthy and diseased arterial tissues were obtained as surplus surgical specimens and freshly processed. We identified that CD90 marks a rare adventitial population that co-expresses MSC markers including PDGFRα, CD44, CD73, and CD105. However, unlike CD90, these additional markers were widely expressed by other cells. Human adventitial CD90+ cells fulfilled standard MSC criteria, including plastic adherence, spindle morphology, passage ability, colony formation, and differentiation into adipocytes, osteoblasts, and chondrocytes. Phenotypic and transcriptomic profiling, as well as adoptive transfer experiments, revealed a potential role in vascular disease pathogenesis, with the transcriptomic disease signature of these cells being represented in an aortic regulatory gene network that is operative in atherosclerosis.

Mitral Regurgitation Exacerbation Due to Sutureless Aortic Valve Replacement.

Sutureless aortic valves are increasingly used for aortic valve replacement (AVR) with excellent outcomes. Implantation requires device expansion in a subannular position within the native aortic root. We report a patient with severe aortic stenosis who received a Perceval sutureless AVR (LivaNova, London, United Kingdom), resulting in a competent prosthesis with an absence of paravalvular leak and aortic regurgitation. However, this implantation resulted in the exacerbation of mitral regurgitation. The sutureless valve required explantation, and a traditional sutured valve was subsequently implanted, which returned the mitral regurgitation to baseline. We discuss a potential etiology of this sutureless AVR-specific complication.

The Use of Branched Endografts for the Aortic Arch in the Endovascular Era.

The endovascular realm has steadily increased its footing in the treatment of the aorta and all of its territories since the foundational case in 1990 by Parodi. The aortic arch, however, continues to be one of the last bastions for treatment via open surgery, which remains the gold standard. Significant comorbidity and prior cardiac surgery prevent open surgery from being the only preferred option, allowing novel endovascular procedures to be considered. Since 1999, more advanced endovascular systems have been created by companies such as Cook Medical, Bolton Medical, Medtronic, Endospan, Gore Medical, and, recently, Kawasumi. The unique shape and angulation of the aortic arch often require the use of custom-made grafts, though arch reconstruction may also include in situ or back-table physician alterations to off-the-shelf devices. The goal of branched endografts is to exclude the aneurysm, while maintaining flow to supra-aortic trunk vessels. Technical success and device durability are limited by the physical constraints of the aortic arch, though greater experience may yield better patient outcomes. Typically, the initial stent-graft (SG) is introduced and deployed into the arch first. Bridging SG are then inserted via axillary or carotid access. Most often, the bridging SG extends from the innominate branch to the distal innominate, and from the left carotid branch to the left common carotid. The major concern is that manipulation of catheters and wires, both within the carotid arteries and aortic arch, create the potential for emboli leading to stroke and paraplegia. The development of endovascular-only techniques for aortic arch pathology will only increase with the aging population of the United States and associated accumulation of comorbidities, making open surgery too grave of a risk.

Hybrid Repair Techniques for Complex Aneurysms and Dissections Involving the Aortic Arch and Thoracic Aorta.

Aortic aneurysms involving the ascending aorta, aortic arch, and descending thoracic aorta have been a challenging entity to surgically treat for over 60 years. Despite the mortality of the disease, early open surgical procedures also had significant morbidity and mortality. The inherent risk in treating multiple anatomic segments simultaneously led to the innovation of the staged elephant trunk (ET) approach by Borst in 1983. To avoid the thoracotomy and associated complications related to the second stage of the procedure, an endovascular completion paradigm was begun by Volodos in 1991. This theoretical hybrid technique combinined shorter and less elaborate open supra-aortic trunk debranching with less invasive endovascular exclusion and has grown since then in terms of different approaches and case volume. The rise of thoracic endovascular aortic repair (TEVAR) combined with debranching bypass has allowed certain lesions to be treated without a large scale intrathoracic open surgical procedure. The complexity and extensiveness of certain lesions, however, has necessitated a hybrid approach such as the frozen elephant trunk (FET) and the standard ET with second stage TEVAR. The former has been used to treat multifocal degenerative aneurysms, chronic dissections with aneurysm, and acute extensive dissections. After conventional proximal aortic replacement, a stent-graft (SG) is delivered antegrade through the transected arch where it is sutured proximally and then "frozen" distally via endovascular means. The FET has the advantage of avoiding a second stage, but potentially introduces a greater rate of spinal cord ischemia compared to the standard elephant trunk. Improvements on the FET procedure have included the development of more advanced hybrid SG such as the Vascutek® Thoraflex™ Hybrid graft (Vascutek Ltd, Scotland, UK), which consists of a distal en,dograft sealed to a proximal four-branched Vascutek Gelweave™ Vascutek Ltd, Scotland, UK) and incorporated sewing collar. While open surgery continues to be a component of complex aortic arch aneurysms, the development of hybrid devices that can bridge the gap between open and endovascular surgery will continue to flourish.

Short-term outcomes in adult cardiac surgery in the use of del Nido cardioplegia solution.

OBJECTIVES: Del Nido cardioplegia in adult cardiac surgery has not been studied although it has been in common use as a "single" dose cardioplegia in pediatric heart surgery. We retrospectively assessed the short-term (in-hospital) clinical outcomes of patients undergoing aortic valve replacement (AVR) using del Nido cardioplegia solution, comparing it to conventional multi-dose whole blood cardioplegia. METHODS: We switched our cardioplegia protocol from conventional whole blood cardioplegia exclusively to del Nido solution in May 2011. In 2011, 240 consecutive patients underwent isolated AVR. One hundred and seventy-eight of them were operated on with the use of del Nido cardioplegia (del Nido group) and whole blood cardioplegia (conventional group) was used in the other 62 patients. Isolated AVR was chosen as a cohort because of its relative simplicity and the similarity of surgical techniques among surgeons. Propensity-score matching identified 54 matched pairs for analysis. RESULTS: The retrograde cardioplegia technique was used in 19 cases (35.2%) in the del Nido group and 52 cases (96.3%) in the conventional group (p<0.001). Mean cardiopulmonary bypass time and mean aortic cross-clamp time were significantly shorter in the del Nido group compared to the conventional group: 71 ± 16 min vs. 84 ± 28 min (p<0.01), 52 ± 14 min vs. 60 ± 16 min (p<0.01), respectively. Postoperative inotropic support was required in 11 patients (20.4 %) in the del Nido group and 13 patients (24.1 %) in the conventional group (p=0.82) with no statistical difference. No patient required a postoperative intra-aortic balloon pump and in-hospital mortality was 0% in both groups. There was no significant difference in postoperative complications between the two groups. CONCLUSIONS: Short-term outcomes in adult cardiac surgery using del Nido solution were acceptable and comparable to conventional multi-dose whole blood cardioplegia. The del Nido cardioplegia technique was associated with shortened cross-clamp times and less frequent utilization of the retrograde cardioplegia delivery technique.

Thoracic aortic aneurysm and dissection.

Aortic dissection is the most devastating complication of thoracic aortic disease. In the more than 250 years since thoracic aortic dissection was first described, much has been learned about diseases of the thoracic aorta. In this review, we describe normal thoracic aortic size; risk factors for dissection, including genetic and inflammatory conditions; the underpinnings of genetic diseases associated with aneurysm and dissection, including Marfan syndrome and the role of transforming growth factor beta signaling; data on the role for medical therapies in aneurysmal disease, including beta-blockers, angiotensin receptor blockers, and angiotensin-converting enzyme inhibitors; prophylactic surgery for aneurysm; surgical techniques for the aortic root; and surgical and endovascular management of aneurysm and dissection for different aortic segments.

Modified bentall procedure with composite biologic grafts.

OBJECTIVES: The search continues for the ideal composite biologic graft (CBG). We have performed aortic root replacements with CBGs, initially with a stented pericardial valve in a Valsalva graft (Gen1) and subsequently with the stentless 3f valve (Gen2). The valve is sewn at the base of the graft sinuses, leaving residual proximal graft to sew separately to the left ventricular outflow tract. This allows for CBG size standardization and permits fabrication prior to bypass. We share our institutional experience and aim to show noninferiority of this technique, as well as discuss potential advantages. METHODS: The first 75 patients to receive each generation of CBG were identified and assessed retrospectively. Overall survival was assessed as our primary outcome. Various secondary outcomes were also analyzed, including operative times and short-term outcomes. RESULTS: Operative times were shorter for Gen2, with cardiopulmonary bypass times that were significantly reduced (126.3 ± 5.2 minutes vs. 157.6 ± 5.8 minutes for Gen1, p = 0.001) and aortic cross-clamp times that trended lower (98.2 ± 4.2 minutes vs. 107.7 ± 3.8 minutes for Gen1, p = 0.095). There were no postoperative myocardial infarctions (MIs) or aortic insufficiency graded 2+ or greater in either group. There was only one stroke in a Gen1 patient who recovered fully. Kaplan-Meier survival analysis showed a strong trend toward improved survival among Gen2 patients (p = 0.0566). CONCLUSIONS: Our experience with Gen2 CBG showed decreased operative times and a trend toward improved survival, though further patient follow-up and larger sample sizes in prospective studies are necessary. Further research with this CBG and additional improvements are warranted.

Feasibility of temporary biventricular pacing after off-pump coronary artery bypass grafting in patients with reduced left ventricular function.

In selected patients undergoing cardiac surgery, our research group previously showed that optimized temporary biventricular pacing can increase cardiac output one hour after weaning from cardiopulmonary bypass. Whether pacing is effective after beating-heart surgery is unknown. Accordingly, in this study we examined the feasibility of temporary biventricular pacing after off-pump coronary artery bypass grafting. The effects of optimized pacing on cardiac output were measured with an electromagnetic aortic flow probe at the conclusion of surgery in 5 patients with a preoperative mean left ventricular ejection fraction of 0.26 (range, 0.15-0.35). Atrioventricular (7) and interventricular (9) delay settings were optimized in randomized order. Cardiac output with optimized biventricular pacing was 4.2 ± 0.7 L/min; in sinus rhythm, it was 3.8 ± 0.5 L/min. Atrial pacing at a matched heart rate resulted in cardiac output intermediate to that of sinus rhythm and biventricular pacing (4 ± 0.6 L/min). Optimization of atrioventricular and interventricular delay, in comparison with nominal settings, trended toward increased flow. This study shows that temporary biventricular pacing is feasible in patients with preoperative left ventricular dysfunction who are undergoing off-pump coronary artery bypass grafting. Further study of the possible clinical benefits of this intervention is warranted.

Quality, not volume, determines outcome of coronary artery bypass surgery in a university-based community hospital network.

OBJECTIVES: The present study examined the relationship between hospital and surgeon coronary artery bypass grafting procedural volume, mortality, morbidity, and National Quality Forum care processes in a university-based community hospital quality improvement program. METHODS: The study population consisted of 2218 consecutive patients undergoing isolated coronary artery bypass grafting from 2007 to 2009 in a university-based quality improvement program that emphasizes involvement of all surgeons in the academic quality endeavor. The endpoints included operative mortality, major morbidity, and National Quality Forum-endorsed process measures as defined by the Society of Thoracic Surgeons. The procedural volume was analyzed as a categorical and continuous variable using general estimating equations, which accounted for clustering effects and which were adjusted for Society of Thoracic Surgeons risk scores and the propensity for operation in a low- versus high-volume program. RESULTS: The annual program volume ranged from 67 to 292 (median, 136; interquartile range, 88-224) and surgeon volume from 1 to 124 (median, 58; interquartile range, 30-89). The mortality rate among the hospitals was 0.47% to 2.23% (0.8% overall), and the observed/expected mortality ranged from 0 to 1.20 (0.41 overall). When comparing low-volume (<200 cases/year) and high-volume centers, no difference was found in the mortality (odds ratio [OR], 1.08; 95% confidence interval [CI], 0.46-2.54, P = .85), morbidity (OR, 1.34; 95% CI, 0.73-2.43), or any of the medication process measures. No difference was found in mortality (OR, 1.59; 95% CI, 0.81-3.13; P = .18), morbidity (OR, 1.20; 95% CI, 0.86-1.66; P = .28), or medication failure (OR, 0.57, 95% CI, 0.3-1.10; P = .10) between the high- and low-volume surgeons (<87). After adjustment for both the Society of Thoracic Surgeons risk score and the propensity score, no association was found for either hospital or surgeon volume with mortality or morbidity. However, a lack of compliance with National Quality Forum measures was highly predictive of morbidity (OR, 1.51; 95% CI, 1.18-1.93; P = .001), regardless of volume, even after adjustment for predicted risk. CONCLUSIONS: In the setting of a university-based community hospital quality improvement program, excellent surgical results can consistently be obtained even in relatively low-volume programs. The surgical outcomes were not associated with program or surgeon volume, but were directly correlated with the focus on quality as manifested by compliance with evidence-based quality standards. Meaningful university affiliation might represent a new quality paradigm for cardiac surgery in the community hospital setting.

Designing a stentless valve conduit for use in a biological Bentall procedure.

Various modifications of the Bentall procedure have been described using mechanical valve conduits. A further modification, using a bioprosthetic valve, has grown in popularity as this prevents the need for lifelong anticoagulation. Additional innovation using a stentless bioprosthetic valve has the theoretical advantages of allowing for a larger bioprosthesis and an improved durability. The technical aspects involved in designing a stentless valve conduit for use in a biological Bentall procedure are described.

Circulating activated and effector memory T cells are associated with calcification and clonal expansions in bicuspid and tricuspid valves of calcific aortic stenosis.

We sought to delineate further the immunological significance of T lymphocytes infiltrating the valve leaflets in calcific aortic stenosis (CAS) and determine whether there were associated alterations in circulating T cells. Using clonotypic TCR ß-chain length and sequence analysis we confirmed that the repertoire of tricuspid CAS valves contains numerous expanded T cell clones with varying degrees of additional polyclonality, which was greatest in cases with severe calcification. We now report a similar proportion of clonal expansions in the much younger bicuspid valve CAS cases. Peripheral blood flow cytometry revealed elevations in HLA-DR(+) activated CD8 cells and in the CD8(+)CD28(null)CD57(+) memory-effector subset that were significantly greater in both bicuspid and tricuspid CAS cases with more severe valve calcification. Lesser increases of CD4(+)CD28(null) T cells were identified, principally in cases with concurrent atherosclerotic disease. Upon immunostaining the CD8 T cells in all valves were mainly CD28(null), and CD8 T cell percentages were greatest in valves with oligoclonal repertoires. T cell clones identified by their clonotypic sequence as expanded in the valve were also found expanded in the circulating blood CD28(null)CD8(+) T cells and to a lesser degree in the CD8(+)CD28(+) subset, directly supporting the relationship between immunologic events in the blood and the valve. The results suggest that an ongoing systemic adaptive immune response is occurring in cases with bicuspid and tricuspid CAS, involving circulating CD8 T cell activation, clonal expansion, and differentiation to a memory-effector phenotype, with trafficking of T cells in expanded clones between blood and the valve.