Race and Ethnicity in Cardiac Surgery: A Missed Opportunity?

BACKGROUND: Patients' race and/or ethnicity are increasingly being associated with differential surgical access and outcomes in cardiac surgery. However, deriving evidence-based conclusions that can inform surgical care has been difficult because of poor diversity in study populations and conflicting research methodology and findings. Using a fictional patient example, this review identifies areas of concern in research engagement, methodology, and analyses, as well as potential steps to improve race and ethnicity considerations in cardiac surgical research. METHODS: A narrative literature review was performed using the PubMed/MEDLINE and Google Scholar databases, with a combination of cardiac surgery, race, ethnicity, and disparities keywords. RESULTS: Less than half of the published cardiac surgery randomized control trials report the race and/or ethnicity of research participants. Racial and/or ethnic minorities make up <20% of most study populations and are significantly underrepresented relative to their proportions of the general population. Further, race and/or ethnicity of research participants is variably categorized based on ancestry, geographic regions, cultural similarities, or minority status. There is growing consideration of analyzing interrelated and confounding variables, such as socioeconomic status, geographic location, or hospital quality, to better elucidate racial and/or ethnic disparities; however, intersectionality considerations remain limited in cardiac surgery research. CONCLUSIONS: Racial and/or ethnic disparities are increasingly being reported in research engagement, cardiac pathologies, and surgical outcomes. To promote equitable surgical care, tangible efforts are needed to recruit racially and/or ethnically minoritized patients to research studies, be transparent and consistent in their groupings, and elucidate the impact of their intersectional social identities.

Comparison of modes of failure and clinical outcomes between explanted porcine and bovine pericardial bioprosthetic valves.

OBJECTIVE: To compare pathological and hemodynamic modes of failure and operative outcomes between explanted porcine and bovine pericardial bioprosthetic valves. METHODS: Patients who underwent explantation of their bioprosthetic valves at Toronto General Hospital from 2007 to 2019 were identified. Retrospective chart review was conducted to attain demographic information, operative outcomes, and echocardiography and pathology reports. RESULTS: A total of 278 patients underwent explantation of their porcine (n=183) or bovine pericardial (n=95) valves. A greater proportion of the porcine group had severe regurgitation, compared to the bovine group (45.3% vs. 19.8%, p<.001). Porcine valves had higher rates of cusp flail (19.4% vs. 3.3%, p<.001). The rates of moderate or worse stenosis were higher among bovine pericardial valves (37.9% vs. 15.8%, p<.001). On pathologic examination, the porcine valves exhibited more cusp tears (67.6% vs. 50.5%, p=.006), while higher incidences of calcification were found in the bovine group (p<.001). Rate of stroke was higher during the explantation procedure of the bovine valves (5.3% vs. 0.5%, p=.040). CONCLUSIONS: The primary mode of failure was regurgitation in porcine valves due to cusp tears and stenosis in bovine valves due to calcification. Establishing a clear understanding of failure modes based on valve material may improve design and guide valve selection at the time of surgery.

Ethiopia's first minimally invasive surgery program: A novel approach in global surgical education.

Objective: Complex lung diseases are among the leading causes of death in Ethiopia. Access to thoracic surgery is limited, and before 2016 no thoracic surgeons were trained in minimally invasive surgery. A global academic partnership was formed between the University of Toronto and Addis Ababa University. We describe implementation of the first minimally invasive surgery training program in sub-Sahara Africa and evaluate its safety. Methods: We performed a retrospective cohort analysis of open versus minimally invasive thoracic and upper gastrointestinal procedures performed at Addis Ababa University from January 2016 to June 2021. Baseline demographic, diagnostic, operative, and postoperative outcomes including length of stay and complications were compared. Results: In our bilateral model of surgical education, training is provided in Ethiopia and Canada over 2 years with a focus on capacity building through egalitarian forms of knowledge exchange. Program features included certification in Fundamentals of Laparoscopic Surgery, high-fidelity lobectomy simulation, and hands-on training. Overall, 41 open and 56 minimally invasive surgery cases were included in the final statistical analysis. The average length of stay in the minimally invasive surgery group was 5.2 days versus 11.0 days in the open group (P < .001). The overall complication rate was 18% in the minimally invasive surgery group versus 39% in the open group (P = .020). Conclusions: We demonstrated the successful initiation of sub-Sahara Africa's first minimally invasive surgery program in thoracic and upper gastrointestinal surgery and characterize its patient safety. We envision the minimally invasive surgery program as a template to continue expanding global partnerships and improving surgical care in other resource-limited settings.

Ascending aortic geometry and its relationship to the biomechanical properties of aortic tissue.

Objective: The objective of this study was to evaluate the relationship between ascending aortic geometry and biomechanical properties. Methods: Preoperative computed tomography scans from ascending aortic aneurysm patients were analyzed using a center line technique (n = 68). Aortic length was measured from annulus to innominate artery, and maximal diameter from this segment was recorded. Biaxial tensile testing of excised tissue was performed to derive biomechanical parameters energy loss (efficiency in performing the Windkessel function) and modulus of elasticity (stiffness). Delamination testing (simulation of dissection) was performed to derive delamination strength (strength between tissue layers). Results: Aortic diameter weakly correlated with energy loss (r 2 = 0.10; P < .01), but not with modulus of elasticity (P = .13) or delamination strength (P = .36). Aortic length was not associated with energy loss (P = .87), modulus of elasticity (P = .13) or delamination strength (P = .90). Using current diameter guidelines, aortas >55 mm (n = 33) demonstrated higher energy loss than those <55 mm (n = 35; P = .05), but no difference in modulus of elasticity (P = .25) or delamination strength (P = .89). A length cutoff of 110 mm was proposed as an indication for repair. Aortas >110 mm (n = 37) did not exhibit a difference in energy loss (P = .40), modulus of elasticity (P = .69), or delamination strength (P = .68) compared with aortas <110 mm (n = 31). Aortas above diameter and length thresholds (n = 21) showed no difference in energy loss (P = .35), modulus of elasticity (P = .55), or delamination strength (P = .61) compared with smaller aortas (n = 47). Conclusions: Aortic geometry poorly reflects the mechanical properties of aortic tissue. Weak association between energy loss and diameter supports intervention at larger diameters. Further research into markers that better capture aortic biomechanics is needed.