Faculty Bibliography

BACKGROUND:The impact of sex on long-term outcomes after pulmonary endarterectomy (PEA) for chronic thromboembolic pulmonary hypertension (CTEPH) remains unclear. We therefore examined the early and long-term outcome after PEA to determine whether sex had an impact on the risk of residual PH and need for targeted PH medical therapy. METHODS:Retrospective study of 401 consecutive patients undergoing PEA at our institution between 08/2005 and 03/2020 was performed. Primary outcome was need for targeted PH medical therapy postoperatively. Secondary outcomes included survival and measures of hemodynamic improvement. RESULTS:Females (n=203, 51%) were more likely to have preoperative home oxygen therapy (29.6% vs 11.6%, p<0.01), and to present with segmental and subsegmental disease compared to males (49.2% vs 21.2%, p<0.01). Despite similar preoperative values, females had higher postoperative pulmonary vascular resistance (final TPR after PEA, 437 Dynes∙s∙cm-5 vs 324 Dynes∙s∙cm-5 in males, p<0.01). Although survival at 10 years was not significantly different between sexes (73% in females vs 84% in males, p=0.08), freedom from targeted PH medical therapy was lower in females (72.9% vs. 89.9% in males at 5 years, p < 0.001). Female sex remained an independent factor affecting the need for targeted PH medical therapy after PEA in multivariate analysis (HR 2.03, 95%CI 1.03-3.98, p=0.04). CONCLUSIONS:Although outcomes are excellent for both sexes, females had greater need for targeted PH medical therapy in the long-term. Early reassessment and long-term follow-up of these patients is important. Further investigations into possible mechanisms to explain the differences is warranted.

Xenotransplantation promises to alleviate the issue of donor organ shortages and to decrease waiting times for transplantation. Recent advances in genetic engineering have allowed for the creation of pigs with up to 16 genetic modifications. Several combinations of genetic modifications have been associated with extended graft survival and life-supporting function in experimental heart and kidney xenotransplants. Lung xenotransplantation carries specific challenges related to the large surface area of the lung vascular bed, its innate immune system's intrinsic hyperreactivity to perceived 'danger', and its anatomic vulnerability to airway flooding after even localized loss of alveolocapillary barrier function. This article discusses the current status of lung xenotransplantation, and challenges related to immunology, physiology, anatomy, and infection. Tissue engineering as a feasible alternative to develop a viable lung replacement solution is discussed.

BACKGROUND:Interhospital transfers of surgical patients are an independent risk factor for mortality. The Australian and New Zealand Audit of Surgical Mortality (ANZASM) aims to improve surgical care through assessment of all cases of surgical mortality. This study aimed to describe common clinical management issues that contributed to interhospital transfer patient mortality. METHODS:Data for all surgical patient mortality in Australia (except New South Wales) that underwent interhospital transfer between 1 January 2010 and 31 December 2019 were extracted from ANZASM. The surgeons' reports and assessors' evaluations were examined to identify clinical management issues. Thematic analysis was performed to develop pertinent themes and subthemes. RESULTS:Some 8679 patients were identified over the 10-year period. Of these, 2171 (25.0 per cent) had 3259 clinical management issues identified. Prominent themes were operative design (n = 466, 14.3 per cent), decision to operate (n = 425, 13.0 per cent), medical conditions (n = 344, 10.6 per cent), diagnosis (n = 326, 10 per cent), transfer (n = 293, 10.0 per cent), intraoperative issues (n = 278, 8.5 per cent), inadequate assessment (n = 238, 7.3 per cent), communication (n = 224, 6.9 per cent), delay in recognizing complications (n = 180, 5.5 per cent), coagulopathy (n = 151, 4.6 per cent), insufficient monitoring (n = 127, 3.9 per cent), infection (n = 107, 3.3 per cent), and hospital resources (n = 100, 3.1 per cent). Assessors considered 58.4 per cent of clinical management issues (n = 1903) probably or definitely preventable. CONCLUSION:This study identified 13 themes of potentially avoidable management issues present in surgical mortality following interhospital transfers. Quality-improvement initiatives targeting these areas may improve surgical patient outcomes.

Lung transplantation remains the only available therapy for many patients with end-stage lung disease. The number of lung transplants performed has increased significantly, but development of the field was slow compared with other solid-organ transplants. This delayed growth was secondary to the increased complexity of transplanting lungs; the continuous needs for surgical, anesthetics, and critical care improvements; changes in immunosuppression and infection prophylaxis; and donor management and patient selection. The future of lung transplant remains promising: expansion of donor after cardiac death donors, improved outcomes, new immunosuppressants targeted to cellular and antibody-mediated rejection, and use of xenotransplantation or artificial lungs.

BACKGROUND:Evolution of surgical practice is influenced by publications in the leading journals of that field. If the authorship of a publication lacks geographical diversity, this could create bias and limit generalizability of the evidence. Accordingly, we conducted a geographical analysis of the leading Cardiothoracic Surgery journals worldwide. METHODS:Using 2020 Impact Factor, we searched the leading Cardiothoracic Surgery journals over the past decade. Only original articles were included. Data regarding first, second and last authors were extracted from every article. From this, we analysed country of affiliation, highest academic degree obtained and author location by metropolitan or rural setting. RESULTS:A total of 12,706 original articles were published in the top 5 ranked Cardiothoracic journals between 2011 and 2020. Authors originated from 69 countries, with the majority being from North America and Western Europe. The United States was the most common country of affiliation (42.8%) in all five journals, with New York City the most prominent city. A total of  63.7% of the authorship originated from large metropolitan areas (estimated as population greater than 500,000 residents), and the most common degrees obtained by authors were MD and PhD. CONCLUSION/CONCLUSIONS:The prominent Cardiothoracic authorship is predominantly located in Western countries, most commonly large metropolitan centers in the United States. This raises questions as to whether the literature adequately reflects populations in other geographical areas such as the continents of South America and Africa and rural settings. Leading journals should consider policies which encourage publication by authors from geographical locations that are underrepresented globally.

Objectives/UNASSIGNED:Proning patients with acute respiratory distress syndrome (ARDS) has been associated with increased survival, though little data exists evaluating the safety and feasibility of proning ARDS patients on extracorporeal membrane oxygenation (ECMO). Methods/UNASSIGNED:, 2020 was performed. All proning events were evaluated for complications, as well as change in compliance, sweep, oxygenation and flow. The primary outcome of this study was the rate major morbidity associated with proning while on ECMO. Results/UNASSIGNED:of 86 pre to 103 post (p<0.0001). Mean ECMO flow was unchanged. Conclusions/UNASSIGNED:Proning in patients with ARDS on ECMO is safe with an associated improvement in lung mechanics. With careful planning and coordination, these data support the practice of appropriately proning patients with severe ARDS, even if they are on ECMO.

INTRODUCTION:The COVID-19 pandemic has had a significant impact on global surgery. In particular, deleterious effects of SARS-CoV-2 infection on the heart and cardiovascular system have been described. To inform surgical patients, we performed a systematic review and meta-analysis aiming to characterize outcomes of COVID-19 positive patients undergoing cardiac surgery. METHODS:The study protocol was registered with PROSPERO (CRD42021228533) and conformed with PRISMA 2020 and MOOSE guidelines. PubMed, Ovid MEDLINE and Web of Science were searched between 1 January 2019 to 24 February 2022 for studies reporting outcomes on COVID-19 positive patients undergoing cardiac surgery. Study screening, data extraction and risk of bias assessment were conducted in duplicate. Meta-analysis was conducted using a random-effects model where at least two studies had sufficient data for that variable. RESULTS:Searches identified 4223 articles of which 18 studies were included with a total 44 patients undergoing cardiac surgery. Within these studies, 12 (66.7%) reported populations undergoing coronary artery bypass graft (CABG) surgery, three (16.7%) aortic valve replacements (AVR) and three (16.7%) aortic dissection repairs. Overall mean postoperative length of ICU stay was 3.39 (95% confidence interval (CI): 0.38, 6.39) and mean postoperative length of hospital stay was 17.88 (95% CI: 14.57, 21.19). CONCLUSION:This systematic review and meta-analysis investigated studies of limited quality which characterized cardiac surgery in COVID-19 positive patients and demonstrates that these patients have poor outcomes. Further issues to be explored are effects of COVID-19 on decision-making in cardiac surgery, and effects of COVID-19 on the cardiovascular system at a cellular level.

OBJECTIVE:We sought to determine the risk factors associated with late mortality or complications (thoracoabdominal aortic aneurysm [TAAA] life-altering events [TALE]: a composite of mortality, permanent paraplegia, permanent dialysis, and stroke) for patients who had undergone endovascular or open TAAA repair. METHODS:We performed a population-based study of patients who had undergone TAAA repair in Ontario, Canada, from 2006 to 2017. The association of baseline risk factors with mortality and complications after repair was examined using Cox hazards models with hospital-specific random effects. The survival of patients who had undergone TAAA repair was compared with that of controls without TAAAs. The two groups were matched by age, sex, area of residence, and average annual household income. The type of repair (endovascular vs open) was included in all models. RESULTS:We identified 664 adults (mean age, 69.3 ± 10.6 years; 71% men) who had undergone TAAA repair. At 5 and 8 years, survival was 55.0% (95% confidence interval [CI], 49.8%-60.1%) and 44.6% (95% CI, 40.4%-49.6%) for patients who had undergone TAAA repair vs 85.6% (95% CI, 83.9%-87.1%) and 76.3% (95% CI, 73.8%-78.8%) for the control population, respectively (hazard ratio [HR], 1.97; 95% CI, 1.67-2.32; P < .01). For the TAAA group, freedom from TALE was 49.2% (95% CI, 44.7%-53.7%) and 37.3% (95% CI, 33.1%-42.4%) at 5 and 8 years of follow-up, respectively. On multivariable analysis, the risk factors associated with mortality during follow-up included older age (HR, 1.21 per 5-year increase; 95% CI, 1.13-1.28), peripheral artery disease (HR, 1.46; 95% CI, 1.03-2.09), hypertension (HR, 1.58; 95% CI, 1.03-2.43), congestive heart failure (HR, 1.78; 95% CI, 1.34-2.36), and urgent procedures (HR, 2.27; 95% CI, 1.74-3.00). A lower rate of death was observed for those with previous coronary revascularization (HR, 0.63; 95% CI, 0.41-0.96) and those who had undergone repair at high-volume institutions (>60 TAAA repairs during the study period; HR, 0.71; 95% CI, 0.55-0.91). Older age, chronic kidney disease, congestive heart failure, and urgent procedures were associated with a higher rate of TALE. The type of repair (endovascular vs open) was not associated with mortality or TALE. CONCLUSIONS:TAAA repair was associated with reduced long-term survival compared with the general population, regardless of the mode of treatment. Urgent or emergent repair was the most profound risk factor for late adverse events. The type of repair (endovascular vs open) was not a predictor of long-term death or complications. Previous coronary revascularization and treatment performed at a high-volume institution were associated with improved late outcomes for patients undergoing TAAA repair.

OBJECTIVE:Determine the long-term outcome and need for additional therapy after pulmonary endarterectomy (PEA) for segmental chronic thromboembolic pulmonary hypertension. METHODS:Retrospective analysis of a prospective cohort of 401 consecutive Canadian patients undergoing PEA between August 2005 and March 2020 in Toronto. The outcome of segmental disease defined as Jamieson type 3 was compared with more proximal disease defined as Jamieson type 1 and 2. The cohort was divided into 3 intervals to analyze the trend over time: 2005-2010, 2011-2015, and 2016-2020. RESULTS:in type 1 or 2 disease (P = .07). Mortality after PEA was similar between type 3 and type 1 and 2 disease at 30-days (2.8% vs 2.3%; P = .8) and at 1 year (7.7% vs 5.5%; P = .4). At 5 years, the survival was lower in type 3 disease (80% vs 91% in type 1 or 2 disease; P = .002). Type 3 disease was an independent predictor for the initiation of pulmonary hypertension-targeted medical therapy after PEA with a cumulative incidence of 38% at 10 years compared with 20% in type 1 and 2 disease (P < .0001). Post-PEA balloon pulmonary angioplasty was predominantly performed in type 3 disease (8% vs 1% in more type 1 or 2 disease; P = .0002). CONCLUSIONS:PEA achieved excellent early and long-term results in segmental chronic thromboembolic pulmonary hypertension. However, patients with segmental disease are at increased risk of requiring additional therapy after PEA and should be carefully monitored.