Use of Sutureless Valve in Aortic Root Enlargement.

AIM: The small aortic annulus is a surgical challenge in patients undergoing aortic valve replacement which may lead to patient prosthesis mismatch. Management options include aortic root enlargement, aortic root replacement, and the use of sutureless valves. In this case series, we report our results with aortic root enlargement, sutureless valve implantation, and benchtop modelling of the radial forces exerted. METHODS: Five patients underwent aortic root enlargement and insertion of the Perceval valve as part of the management strategy to enlarge their effective orifice area. We further investigate this strategy with a benchtop model to quantify the radial forces exerted by the Perceval valve on the aortic annulus. Radial and hoop forces on the aortic annulus and inner ring of the Perceval valve were recorded using a Mylar force tester. RESULTS: Five female patients with native annulus between 18mm-20mm underwent root enlargement and insertion of a Perceval S valve. The postoperative course was uncomplicated for all patients except for one who required a permanent pacemaker insertion. Transvalvular pressure gradients remained low at up to 4 years of follow-up (12 mmHg-21 mmHg), with no evidence of paravalvular leak. Benchtop testing demonstrated radial forces exerted at the annulus in all-size Perceval S valves to be within physiological variables, whereas compressive forces required to deform the valves were supraphysiological. CONCLUSIONS: The deployment of a sutureless valve within a surgical enlarged aortic root is a feasible solution in patients with a small aortic root.

The pathophysiology and management of depression in cardiac surgery patients.

Background: Depression is common in the cardiac surgery population. This contemporary narrative review aims to explore the main pathophysiological disturbances underpinning depression specifically within the cardiac surgery population. The common non-pharmacological and pharmacological management strategies used to manage depression within the cardiac surgery patient population are also explored. Methods: A total of 1291 articles were identified through Ovid Medline and Embase. The findings from 39 studies were included for qualitative analysis in this narrative review. Results: Depression is associated with several pathophysiological and behavioral factors which increase the likelihood of developing coronary heart disease which may ultimately require surgical intervention. The main pathophysiological factors contributing to depression are well characterized and include autonomic nervous system dysregulation, excessive inflammation and disruption of the hypothalamic-pituitary-adrenal axis. There are also several behavioral factors in depressed patients associated with the development of coronary heart disease including poor diet, insufficient exercise, poor compliance with medications and reduced adherence to cardiac rehabilitation. The common preventative and management modalities used for depression following cardiac surgery include preoperative and peri-operative education, cardiac rehabilitation, cognitive behavioral therapy, religion/prayer/spirituality, biobehavioral feedback, anti-depressant medications, and statins. Conclusion: This contemporary review explores the pathophysiological mechanisms leading to depression following cardiac surgery and the current management modalities. Further studies on the preventative and management strategies for postoperative depression in the cardiac surgery patient population are warranted.

A Qualitative Analysis of Access to Healthcare Among African American Adults in South Carolina.

Access to healthcare is a Social Determinant of Health that is associated with public health outcomes and barriers to access disproportionately affect African American adults. This study used a health and financial literacy approach to qualitatively assess how African American adults access healthcare and potential barriers faced (n = 20). Results indicated a wide range of experiences generally split between positive and negative experiences in access to healthcare. Specific themes that emerged included scheduling issues and appointment availability, expense of care, lack of transparency in insurance coverage, the need for more primary care clinics and enhanced community outreach and education on how to access healthcare. This research identifies a need for increased education surrounding health insurance coverage and an identified need for more local physicians or ease of scheduling. All participants in this study stated they were covered by health insurance of some form. Future research should examine these issues in the context of socioeconomic and insurance status.

An Update on Postoperative Cognitive Dysfunction Following Cardiac Surgery.

Postoperative cognitive dysfunction is extremely prevalent following cardiac surgery. The increasing patient age and comorbidity profile increases their susceptibility to cognitive impairment. The underlying pathophysiological mechanisms leading to cognitive impairment are not clearly elucidated. Using the contemporary literature (2015-present), this narrative review has three aims. Firstly, to provide an overview of postoperative cognitive impairment. Secondly, to analyse the predominant pathophysiological mechanisms leading to cognitive dysfunction following cardiac surgery such as inflammation, cerebral hypoperfusion, cerebral microemboli, glycaemic control and anaesthesia induced neurotoxicity. Lastly, to assess the current therapeutic strategies of interest to address these pathophysiological mechanisms, including the administration of dexamethasone, the prevention of prolonged cerebral desaturations and the monitoring of cerebral perfusion using near-infrared spectroscopy, surgical management strategies to reduce the neurological effects of microemboli, intraoperative glycaemic control strategies, the effect of volatile vs. intravenous anaesthesia, and the efficacy of dexmedetomidine.

The experiences, attitudes and understanding of research amongst medical students at an Australian medical school.

BACKGROUND: Research engagement plays an integral role in developing clinicians that practice effective, evidence-based medicine. Research participation by clinicians, however, is declining. Given the link between research during medical school and future research output, promotion of medical student research is one avenue by which this shortage can be addressed. Student research attitudes and participation in Australia are not well-documented in the literature. This study therefore aims to investigate research practices, motivators, and barriers amongst Australian medical students in order to determine whether there is a need for further integration of research within Australian medical school curriculums. METHODS: A cross-sectional study design was used to explore research experience and attitudes, as well as the enablers and barriers to research amongst students enrolled in all years of the five-year medical course at Monash University. A questionnaire was created by combining questions from several surveys on medical student research and comprised Likert scales, multiple choice options and free-text responses assessing research experience, attitudes, motivators, and barriers. RESULTS: Seven hundred and four respondents (69.4% female; survey response rate 36.7%) reported variable research experience and interest. Less than half of the cohort (n = 296; 44.9%) had contributed to a research project. Increasing employability for specialty training programs was the primary motivating factor (n = 345; 51.9%) for pursuing research, with only 20.5% (n = 136) citing an interest in academia as a motivator. Time constraints (n = 460; 65.3%) and uncertainty surrounding how to find research opportunities (n = 449; 63.8%) were the most common barriers to research. CONCLUSIONS: Medical students at Monash University are interested in but have limited experience with research. Students are, however, primarily motivated by the prospect of increasing employability for specialist training; medical schools should therefore focus on encouraging intrinsic motivation for pursuing research. Greater integration of research education and opportunities within medical school curricula may also be required to provide students with the skills necessary to both pursue research and practice evidence-based medicine.

Donor-acceptor biomorphs from the ionic self-assembly of porphyrins.

Microscale four-leaf clover-shaped structures are formed by self-assembly of anionic and cationic porphyrins. Depending on the metal complexed in the porphyrin macrocycle (Zn or Sn), the porphyrin cores are either electron donors or electron acceptors. All four combinations of these two metals in cationic tetra(N-ethanol-4-pyridinium)porphyrin and anionic tetra(sulfonatophenyl)porphyrin result in related cloverlike structures with similar crystalline packing indicated by X-ray diffraction patterns. The clover morphology transforms as the ionic strength and temperature of the self-assembly reaction are increased, but the structures maintain 4-fold symmetry. The ability to alter the electronic and photophysical properties of these solids (e.g., by altering the metals in the porphyrins) and to vary cooperative interactions between the porphyrin subunits raises the possibility of producing binary solids with tunable functionality. For example, we show that the clovers derived from anionic Zn porphyrins (electron donors) and cationic Sn porphyrins (electron acceptors) are photoconductors, but when the metals are reversed in the two porphyrins, the resulting clovers are insulators.