Artificial intelligence in cardiac surgery: A systematic review.

BACKGROUND: Artificial intelligence (AI) has emerged as a tool to potentially increase the efficiency and efficacy of cardiovascular care and improve clinical outcomes. This study aims to provide an overview of applications of AI in cardiac surgery. METHODS: A systematic literature search on AI applications in cardiac surgery from inception to February 2024 was conducted. Articles were then filtered based on the inclusion and exclusion criteria and the risk of bias was assessed. Key findings were then summarized. RESULTS: A total of 81 studies were found that reported on AI applications in cardiac surgery. There is a rapid rise in studies since 2020. The most popular machine learning technique was random forest (n = 48), followed by support vector machine (n = 33), logistic regression (n = 32), and eXtreme Gradient Boosting (n = 31). Most of the studies were on adult patients, conducted in China, and involved procedures such as valvular surgery (24.7%), heart transplant (9.4%), coronary revascularization (11.8%), congenital heart disease surgery (3.5%), and aortic dissection repair (2.4%). Regarding evaluation outcomes, 35 studies examined the performance, 26 studies examined clinician outcomes, and 20 studies examined patient outcomes. CONCLUSION: AI was mainly used to predict complications following cardiac surgeries and improve clinicians' decision-making by providing better preoperative risk assessment, stratification, and prognostication. While the application of AI in cardiac surgery has greatly progressed in the last decade, further studies need to be conducted to verify accuracy and ensure safety before use in clinical practice.

Global Access to Cardiac Surgery Centers: Distribution, Disparities, and Targets.

BACKGROUND: Global data on cardiac surgery centers are outdated and survey-based. In 1995, there were 0.7 centers per million population, ranging from one per 120,000 in North America to one per 33 million in sub-Saharan Africa. This study analyzes the contemporary distribution of cardiac surgery centers and proposes targets relative to countries' cardiovascular disease (CVD) burdens. METHODS: Medical databases, gray literature, and governmental reports were used to identify the most recent post-2010 data that describe the number of centers performing cardiac surgery in each nation. The 2019 Institute for Health Metrics and Evaluation Global Burden of Disease Results Tool provided national CVD burdens. One-third of the CVD burden was assumed to be surgical. Center targets were proposed as the average or half of the average of centers per million surgical CVD patients in high-income countries. RESULTS: 5,111 cardiac surgery centers were identified across 230 nations and territories with available data, equaling 0.73 centers per million population. The median (interquartile range) number of centers ranged from 0 (0-0.06) per million in low-income countries to 0.75 (0-1.44) in high-income countries. Targets were 612.2 (optimistic) or 306.1 (conservative) centers per million surgical CVD incidence. In 2019, low-income, lower-middle-income, and upper-middle-income countries possessed 34.8, 149.0, and 271.9 centers per million surgical CVD incidence. CONCLUSION: Little progress has been made to increase cardiac surgery centers per population despite growing CVD burdens. Today's global cardiac surgical capacity remains insufficient, disproportionately affecting the world's poorest regions.

Health System Needs to Establish Cardiac Surgery Centers.

Cardiovascular diseases are the leading cause of mortality worldwide, responsible for nearly 18 million deaths each year. More than 80% of these take place in low- and middle-income countries (LMICs), where access to cardiac surgical services is scarce. Approximately 93% of the LMIC population, or six billion people worldwide, are estimated to lack access to safe, timely, and affordable cardiac surgical care as a result of workforce, infrastructure, financial, and quality barriers. Various models have been proposed and attempted to establish cardiac surgery centers in LMICs; however, only some have been successful in achieving sustainable local services. Here, we describe the workforce, infrastructure, financial, and political needs and considerations from a health systems perspective to establish a cardiac surgery center.

Cerebral protection in acute type A aortic dissection surgery: a systematic review and meta-analysis.

Background: Acute type A aortic dissection (ATAAD) still challenges physicians and warrants emergent surgical management. Two main methods to reduce cerebrovascular events in ATAAD surgeries are antegrade cerebral perfusion (ACP) and retrograde cerebral perfusion (RCP). We conducted a systematic review and meta-analysis to compare the outcomes of ACP and RCP methods during the ATAAD surgery. Methods: In this study, we searched the databases until March 29th, 2023. Studies that reported the data for comparison of different types of brain perfusion protection during aortic surgery in patients with ATAAD were included. Results: Twenty-six studies met the eligibility criteria. All studies had a low risk of bias as they were evaluated by the Joanna Briggs Institute (JBI) critical appraisal tool. Eventually, we included 26 studies in the current meta-analysis, and a total of 13,039 patients were evaluated. The calculated risk ratio (RR) for permanent neurologic dysfunction (PND) in ACP and RCP comparison was RR =1.23, 95% confidence interval (CI): (0.84, 1.80) (P value =0.2662), and in unilateral ACP (uACP) and bilateral ACP (bACP) was RR =1.2786, 95% CI: (0.7931, 2.0615) (P value =0.3132). When comparing the ACP-RCP and uACP-bACP groups, significant differences were found between ACP-RCP the groups in terms of circulatory arrest time (P value =0.0017 and P value =0.1995, respectively), cardiopulmonary bypass time (P value =0.5312 and P value =0.7460, respectively), intensive care unit (ICU)-stay time (P value =0.2654 and P value =0.0099), crossclamp time (P value =0.6228 and P value =0.2625), and operative mortality (P value =0.9368 and P value =0.2398, respectively), and when comparing the u-ACP and b-ACP groups for transient neurologic deficit (TND), an RR of 1.32, 95% CI: (1.05, 1.67) (P value =0.0199). The results showed high heterogeneity and no publication bias. Conclusions: This study demonstrated that the ACP and RCP are both safe and acceptable techniques to use in emergent settings. The uACP technique is equivalent to bACP in terms of PND and mortality, however, uACP is preferred over bACP in terms of TND.

Echocardiogram Vector Embeddings Via R3D Transformer for the Advancement of Automated Echocardiography.

Background: Ejection fraction (EF) estimation informs patient plans in the ICU, and low EF can indicate ventricular systolic dysfunction, which increases the risk of adverse events including heart failure. Automated echocardiography models are an attractive solution for high-variance human EF estimation, and key to this goal are echocardiogram vector embeddings, which are a critical resource for computational researchers. Objectives: The authors aimed to extract the vector embeddings from each echocardiogram in the EchoNet dataset using a classifier trained to classify EF as healthy (>50%) or unhealthy (<= 50%) to create an embeddings dataset for computational researchers. Methods: We repurposed an R3D transformer to classify whether patient EF is below or above 50%. Training, validation, and testing were done on the EchoNet dataset of 10,030 echocardiograms, and the resulting model generated embeddings for each of these videos. Results: We extracted 400-dimensional vector embeddings for each of the 10,030 EchoNet echocardiograms using the trained R3D model, which achieved a test AUC of 0.916 and 87.5% accuracy, approaching the performance of comparable studies. Conclusions: We present 10,030 vector embeddings learned by this model as a resource to the cardiology research community, as well as the trained model itself. These vectors enable algorithmic improvements and multimodal applications within automated echocardiography, benefitting the research community and those with ventricular systolic dysfunction (https://github.com/Team-Echo-MIT/r3d-v0-embeddings).

Decentralization and Integration of Advanced Cardiac Care for the World's Poorest Billion Through the PEN-Plus Strategy for Severe Chronic Non-Communicable Disease.

Rheumatic and congenital heart disease, cardiomyopathies, and hypertensive heart disease are major causes of suffering and death in low- and lower middle-income countries (LLMICs), where the world's poorest billion people reside. Advanced cardiac care in these counties is still predominantly provided by specialists at urban tertiary centers, and is largely inaccessible to the rural poor. This situation is due to critical shortages in diagnostics, medications, and trained healthcare workers. The Package of Essential NCD Interventions - Plus (PEN-Plus) is an integrated care model for severe chronic noncommunicable diseases (NCDs) that aims to decentralize services and increase access. PEN-Plus strategies are being initiated by a growing number of LLMICs. We describe how PEN-Plus addresses the need for advanced cardiac care and discuss how a global group of cardiac organizations are working through the PEN-Plus Cardiac expert group to promote a shared operational strategy for management of severe cardiac disease in high-poverty settings.

Correction: Decentralization and Integration of Advanced Cardiac Care for the World's Poorest Billion Through the PEN-Plus Strategy for Severe Chronic Non-Communicable Disease.

[This corrects the article DOI: 10.5334/gh.1313.].

Comparing the effectiveness and lubricity of a novel Shea lubricant to 2% lidocaine gel for digital rectal examination: a randomized non-inferiority trial.

This study compared the level of lubricity and pain reduction of a novel shea lubricant to 2% lidocaine gel during digital rectal examination (DRE). Our research group performed a 9-week single-blind non-inferiority trial at the Ho Teaching Hospital involving 153 patients. The primary outcome measure was the mean pain difference during the procedure using a Visual Analogue Scale. 75 and 78 patients were randomized to the shea lubricant and 2% lidocaine gel groups respectively. The analysis considered the per-protocol population. The mean pain difference at endpoint was Δ - 0.01. The 95% lower confidence interval was a -0.595 difference in means, above the non-inferiority (NI) limit of - 0.720, thus establishing non-inferiority (Δ - 0.01, 95% CI - 0.59 to 0.57, NI - 0.72). With secondary outcome measures, perianal pruritus (p = 0.728), discomfort (p = 0.446), bowel urgency (p = 0.077) and urinary urgency (p = 0.841) were similar during the procedure. Shea lubricant had better lubricity and ease of use (p = 0.002). While the novel shea lubricant achieved similar level of pain reduction as obtained with 2% lidocaine gel, it had better ease of performance and lubricity.

Heart murmur detection from phonocardiogram recordings: The George B. Moody PhysioNet Challenge 2022.

Cardiac auscultation is an accessible diagnostic screening tool that can help to identify patients with heart murmurs, who may need follow-up diagnostic screening and treatment for abnormal cardiac function. However, experts are needed to interpret the heart sounds, limiting the accessibility of cardiac auscultation in resource-constrained environments. Therefore, the George B. Moody PhysioNet Challenge 2022 invited teams to develop algorithmic approaches for detecting heart murmurs and abnormal cardiac function from phonocardiogram (PCG) recordings of heart sounds. For the Challenge, we sourced 5272 PCG recordings from 1452 primarily pediatric patients in rural Brazil, and we invited teams to implement diagnostic screening algorithms for detecting heart murmurs and abnormal cardiac function from the recordings. We required the participants to submit the complete training and inference code for their algorithms, improving the transparency, reproducibility, and utility of their work. We also devised an evaluation metric that considered the costs of screening, diagnosis, misdiagnosis, and treatment, allowing us to investigate the benefits of algorithmic diagnostic screening and facilitate the development of more clinically relevant algorithms. We received 779 algorithms from 87 teams during the Challenge, resulting in 53 working codebases for detecting heart murmurs and abnormal cardiac function from PCG recordings. These algorithms represent a diversity of approaches from both academia and industry, including methods that use more traditional machine learning techniques with engineered clinical and statistical features as well as methods that rely primarily on deep learning models to discover informative features. The use of heart sound recordings for identifying heart murmurs and abnormal cardiac function allowed us to explore the potential of algorithmic approaches for providing more accessible diagnostic screening in resource-constrained environments. The submission of working, open-source algorithms and the use of novel evaluation metrics supported the reproducibility, generalizability, and clinical relevance of the research from the Challenge.

Tertiary prevention and treatment of rheumatic heart disease: a National Heart, Lung, and Blood Institute working group summary.

Although entirely preventable, rheumatic heart disease (RHD), a disease of poverty and social disadvantage resulting in high morbidity and mortality, remains an ever-present burden in low-income and middle-income countries (LMICs) and rural, remote, marginalised and disenfranchised populations within high-income countries. In late 2021, the National Heart, Lung, and Blood Institute convened a workshop to explore the current state of science, to identify basic science and clinical research priorities to support RHD eradication efforts worldwide. This was done through the inclusion of multidisciplinary global experts, including cardiovascular and non-cardiovascular specialists as well as health policy and health economics experts, many of whom also represented or closely worked with patient-family organisations and local governments. This report summarises findings from one of the four working groups, the Tertiary Prevention Working Group, that was charged with assessing the management of late complications of RHD, including surgical interventions for patients with RHD. Due to the high prevalence of RHD in LMICs, particular emphasis was made on gaining a better understanding of needs in the field from the perspectives of the patient, community, provider, health system and policy-maker. We outline priorities to support the development, and implementation of accessible, affordable and sustainable interventions in low-resource settings to manage RHD and related complications. These priorities and other interventions need to be adapted to and driven by local contexts and integrated into health systems to best meet the needs of local communities.

Recommendations for developing effective and safe paediatric and congenital heart disease services in low-income and middle-income countries: a public health framework.

The global burden of paediatric and congenital heart disease (PCHD) is substantial. We propose a novel public health framework with recommendations for developing effective and safe PCHD services in low-income and middle-income countries (LMICs). This framework was created by the Global Initiative for Children's Surgery Cardiac Surgery working group in collaboration with a group of international rexperts in providing paediatric and congenital cardiac care to patients with CHD and rheumatic heart disease (RHD) in LMICs. Effective and safe PCHD care is inaccessible to many, and there is no consensus on the best approaches to provide meaningful access in resource-limited settings, where it is often needed the most. Considering the high inequity in access to care for CHD and RHD, we aimed to create an actionable framework for health practitioners, policy makers and patients that supports treatment and prevention. It was formulated based on rigorous evaluation of available guidelines and standards of care and builds on a consensus process about the competencies needed at each step of the care continuum. We recommend a tier-based framework for PCHD care integrated within existing health systems. Each level of care is expected to meet minimum benchmarks and ensure high-quality and family centred care. We propose that cardiac surgery capabilities should only be developed at the more advanced levels on hospitals that have an established foundation of cardiology and cardiac surgery services, including screening, diagnostics, inpatient and outpatient care, postoperative care and cardiac catheterisation. This approach requires a quality control system and close collaboration between the different levels of care to facilitate the journey and care of every child with heart disease. This effort was designed to guide readers and leaders in taking action, strengthening capacity, evaluating impact, advancing policy and engaging in partnerships to guide facilities providing PCHD care in LMICs.

A Simplified Adult Expiratory Support Device: First Clinical Cases in a Low-Resource Setting.

PURPOSE: In low and middle-income countries, mechanical ventilators or commercially available devices used to offer continuous positive airway pressure are not readily affordable and available. In Ghana, nearly 10% of critically ill patients presenting to the emergency department require ventilator support. DESCRIPTION: We designed, built, and tested a simple expiratory positive airway pressure (EPAP) device to provide adult respiratory support in low resource environments with or without supplemental oxygen and without the need for electricity. EVALUATION: Laboratory tests demonstrated that the device is capable of delivering EPAP at levels expected to provide significant assistance to some patients. We present the first 2 cases where the use of this simple EPAP device provided critical respiratory support during weaning of patients from mechanical ventilation. CONCLUSIONS: A low-cost 3-dimensional printable adult respiratory support device could provide substantial benefit to patients suffering from respiratory distress through the delivery of appropriate levels of EPAP in a low-resource setting with limited infrastructure. Further clinical validation is needed for broader application in low-resource settings.

A scoping review of artificial intelligence applications in thoracic surgery.

OBJECTIVES: Machine learning (ML) has great potential, but there are few examples of its implementation improving outcomes. The thoracic surgeon must be aware of pertinent ML literature and how to evaluate this field for the safe translation to patient care. This scoping review provides an introduction to ML applications specific to the thoracic surgeon. We review current applications, limitations and future directions. METHODS: A search of the PubMed database was conducted with inclusion requirements being the use of an ML algorithm to analyse patient information relevant to a thoracic surgeon and contain sufficient details on the data used, ML methods and results. Twenty-two papers met the criteria and were reviewed using a methodological quality rubric. RESULTS: ML demonstrated enhanced preoperative test accuracy, earlier pathological diagnosis, therapies to maximize survival and predictions of adverse events and survival after surgery. However, only 4 performed external validation. One demonstrated improved patient outcomes, nearly all failed to perform model calibration and one addressed fairness and bias with most not generalizable to different populations. There was a considerable variation to allow for reproducibility. CONCLUSIONS: There is promise but also challenges for ML in thoracic surgery. The transparency of data and algorithm design and the systemic bias on which models are dependent remain issues to be addressed. Although there has yet to be widespread use in thoracic surgery, it is essential thoracic surgeons be at the forefront of the eventual safe introduction of ML to the clinic and operating room.

Cardiac Surgery in Low- and Middle-Income Countries: A State-of-the-Art Review.

BACKGROUND: Six billion people in low- and middle-income countries (LMICs) lack timely or ready access to safe and affordable cardiac surgical care when needed, which remains a low priority on the global public health and global surgery agenda. Here, we report the results of a state-of-the-art review of cardiac surgical care in LMICs to highlight the important milestones and current progress as well as the challenges associated with the expansion of sustainable global cardiac surgery for those in need. METHODS: A literature review was performed searching the PubMed/MEDLINE and Google Scholar databases using a combination of cardiac surgery, global health, and LMIC keywords. The Institute for Health Metrics and Evaluation Global Burden of Disease Results Tool was used to assess the global burden of disease related to cardiovascular surgical diseases. RESULTS: High-income countries are estimated to have more than 100 times as many cardiac surgeons per million population compared with low-income countries. There are more than 4000 cardiac centers worldwide, but less than 1 center per 10 million population in LMICs. Approximately 1.5 million cardiac operations are performed globally, of which a disproportionally low number are in LMICs. Despite the high costs associated with cardiac operations, recent data suggest the favorable cost-effectiveness thereof in LMICs. Opportunities arise to sustainably integrate cardiac surgery in holistic health systems strengthening interventions. CONCLUSIONS: Skepticism underlying the need, feasibility, and cost-effectiveness of cardiac surgery in LMICs prevails, but recent advances, successful case studies, and existing data illustrate the potential of expanding cardiac care globally.

Pre-existing cardiovascular disease, acute kidney injury, and cardiovascular outcomes in hospitalized blacks with COVID-19 infection.

BACKGROUND: The Corona Virus 19 (COVID-19) infection is associated with worse outcomes in blacks, although the mechanisms are unclear. We sought to determine the significance of black race, pre-existing cardiovascular disease (pCVD), and acute kidney injury (AKI) on cardiopulmonary outcomes and in-hospital mortality of COVID-19 patients. METHODS: We conducted a retrospective cohort study of blacks with/without pCVD and with/without in-hospital AKI, hospitalized within Grady Memorial Hospital in Georgia between February and July 2020, who tested positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on qualitative polymerase-chain-reaction assay. The primary outcome was a composite of in-hospital cardiac events. RESULTS: Of the 293 patients hospitalized with COVID-19 in this study, 71 were excluded from the primary analysis (for race/ethnicity other than black non-Hispanic). Of the 222 hospitalized COVID-19 patients included in our analyses, 41.4% were female, 78.8% had pCVD, and 30.6% developed AKI during the admission. In multivariable analyses, pCVD (OR 4.7, 95% CI 1.5-14.8, P=0.008) and AKI (OR 2.7, 95% CI 1.3-5.5, P=0.006) were associated with increased odds of in-hospital cardiac events. AKI was associated with increased odds of in-hospital mortality (OR 8.9, 95% CI 3.3-23.9, P<0.0001). The presence of AKI was associated with increased odds of ICU stay, mechanical ventilation, and acute respiratory distress syndrome (ARDS). CONCLUSION: pCVD and AKI were associated with higher risk of in-hospital cardiac events, and AKI was associated with a higher risk of in-hospital mortality in blacks.

Hybrid cardiovascular suite: the operating room of the future.

The evolving specialty of cardiovascular hybrid surgery that involves the integration of advanced interventional techniques into cardiovascular surgery requires sophisticated angiographic imaging capabilities in the operating room (hybrid suite). This new operating-room concept enables new cardiac-surgery therapies and will play a vital role for the advancement of minimally invasive cardiovascular surgery. Careful planning and professional expertise is a key factor for every hybrid room project.

Access platform techniques for transcatheter aortic valve replacement.

BACKGROUND: One of the unique variables for successful implantation of transcatheter aortic valves involves the ability to secure an access route for deployment of the aortic valve. AIM OF STUDY: A large number of the high-risk patients with critical aortic stenosis referred for transcatheter valve implantation approach may not be candidates for the femoral approach due to peripheral vascular disease with the morbidity and mortality increased severalfold in patients who develop access related complications. METHOD & RESULTS: A thorough knowledge and review of various alternate access site techniques and trouble shooting are therefore important and required by the implanting cardiac surgeons involved in transcatheter aortic valve therapy. CONCLUSION: The article review highlights the various percutaneous, hybrid, and surgical access techniques platforms available as well as options for implantation of these devices.

"Cracking and paving": a novel technique to deliver a thoracic endograft despite ilio-femoral occlusive disease.

BACKGROUND: The use of endoluminal grafts to treat thoracic aortic aneurysms has been associated with a decreased morbidity and mortality compared with open thoracic aortic aneurysm repair. High-risk surgical patients with ilio-femoral occlusive disease may not be amenable to general anesthesia and the construction of a retroperitoneal conduit. METHODS AND RESULTS: We report the use of a novel technique consisting of cracking and paving of the ilio-femoral vessels with balloon angioplasty, followed by deployment of an endoconduit to deliver an endoluminal graft under local sedation to treat a high-risk 80-year-old patient with a thoracic aneurysm. CONCLUSION: High-risk surgical patients with iliofemoral disease can undergo endoluminal graft therapy to threat thoracic aortic aneurysms.

An Exploration of Myths, Barriers, and Strategies for Improving Diversity Among STS Members.

Diversity within health care organizations has many proven benefits, yet women and other groups remain underrepresented in cardiothoracic surgery. We sought to explore responses from a Society of Thoracic Surgeons (STS) survey to identify myths and barriers for informing organizational strategies in the STS and cardiothoracic surgery. We performed a qualitative review of narrative survey responses within three domains surrounding diversity in cardiothoracic surgery: myths, barriers, and strategies for improvement. Common diversity myths included diversity as a pipeline problem (24%), diversity equated to exclusivity (21%), and diversity not supporting meritocracy (18%). The most frequent barrier code was perceived prejudice (22%). Suggested strategies toward improvement were culture change prioritizing diversity (22%) and training the leaders (14%). Notably, 15% of response codes reflected the belief that disparities do not exist; thus, the issue should not be prioritized by the organization. The results do not necessarily reflect the beliefs of most of the STS membership; nonetheless, they provide important insight critical to guide any efforts toward eliminating disparities within cardiothoracic surgery and improving the care of our patients.