Continuous Venous-Arterial Doppler Ultrasound During a Preload Challenge

A preload challenge (PC) is a clinical maneuver that, first, increases the cardiac filling (i.e., preload) and, second, calculates the change in cardiac ...

Health Sciences North Research Institute

Northern Ontario School of Medicine

Stem cell transplantation is a promising approach for improving cardiac function after severe myocardial damage, for which the use of autologous donor cells has been preferred to avoid immune rejection. Recently, however, rodent as well as human mesenchymal stem cells have been reported to be uniquely immune-tolerant, in both in vitro and in vivo transplant models. In this review, we explore in detail the current understanding of the underlying immunologic mechanisms, which can facilitate the use of such cells as "universal donor cells" with fascinating clinical implications.

Concise review: immunomodulatory properties of mesenchymal stem cells in cellular transplantation: update, controversies, and unknowns.

Stem cell treatments are a desirable therapeutic option to regenerate myocardium and improve cardiac function after myocardial infarction. Several different types of cells have been explored, each with their own benefits and limitations. Induced pluripotent stem cells possess an embryonic-like state and therefore have a high proliferative capacity, but they also pose a risk of teratoma formation. Mesenchymal stem cells have been investigated from both bone marrow and adipose tissue. Their immunomodulatory characteristics may permit the use of allogeneic cells as universal donor cells in the future. Lastly, studies have consistently shown that cardiac stem cells are better able to express markers of cardiogenesis compared to other cell types, as well improve cardiac function. The ideal source of stem cells depends on multiple factors such as the ease of extraction/isolation, effectiveness of engraftment, ability to differentiate into cardiac lineages and effect on cardiac function. Although multiple studies highlight the benefits and limitations of each cell type and reinforce the successful potential use of these cells to regenerate damaged myocardium, more studies are needed to directly compare cells from various sources. It is interesting to note that research using stem cell therapies is also expanding to treat other cardiovascular diseases including non-ischemic cardiomyopathies.

Therapeutic use of stem cells for cardiovascular disease.

Myocardial infarction is a leading cause of morbidity and mortality worldwide. Although medical and surgical treatments can significantly improve patient outcomes, no treatment currently available is able to generate new contractile tissue or reverse ischemic myocardium. Driven by the recent/novel understanding that regenerative processes do exist in the myocardium-tissue previously thought not to possess regenerative properties-the use of stem cells has emerged as a promising therapeutic approach with high expectations. The literature describes the use of cells from various sources, categorizing them as either embryonic, induced pluripotent, or adult/tissue stem cells (mesenchymal, hematopoietic, skeletal myoblasts, cardiac stem cells). Many publications show the successful use of these cells to regenerate damaged myocardium in both animal and human models; however, more studies are needed to directly compare cells of various origins in efforts to draw conclusions on the ideal source. Although numerous challenges exist in this developing area of research and clinical practice, prospects are encouraging. The following aims to provide a concise review outlining the different types of stem cells used in patients after myocardial infarction.

Therapeutic Use of Stem Cells for Myocardial Infarction.

Diaphragmatic eventration in old age is a rare phenomenon. Typically, it is thought to originate as a result of failure of development of the muscles of the diaphragm. Less commonly, it can occur secondary to acquired conditions resulting from spinal cord or phrenic nerve injury and is only detected incidentally when the patient presents with dyspnea, chest infection, or cardiac compression symptoms. Herein, we report a case of right diaphragmatic paralysis in a 58-year-old man with a presentation of marked elevation of the right hemidiaphragm and ascites causing a picture compatible with cardiac tamponade.

An Unusual Case of Cardiac Tamponade Secondary to an Elevated Right Hemidiaphragm.

Coronary artery bypass grafting with cardiopulmonary bypass (CPB) induces an inflammatory reaction that is associated with postoperative complications. Influenza vaccination has been shown to decrease cardiovascular morbidity in patients with cardiovascular disease, possibly via its anti-inflammatory properties. We hypothesize that influenza vaccination would attenuate the inflammatory reaction after CPB.

Influenza Vaccination Blunts the Inflammatory Response in Patients Undergoing Cardiopulmonary Bypass.

Heart failure continues to be one of the leading causes of morbidity and mortality worldwide. Myocardial infarction is the primary causative agent of chronic heart failure resulting in cardiomyocyte necrosis and the subsequent formation of fibrotic scar tissue. Current pharmacological and non-pharmacological therapies focus on managing symptoms of heart failure yet remain unable to reverse the underlying pathology. Heart transplantation usually cannot be relied on, as there is a major discrepancy between the availability of donors and recipients. As a result, heart failure carries a poor prognosis and high mortality rate. As the heart lacks significant endogenous regeneration potential, novel therapeutic approaches have incorporated the use of stem cells as a vehicle to treat heart failure as they possess the ability to self-renew and differentiate into multiple cell lineages and tissues. This review will discuss past, present, and future clinical trials, factors that influence stem cell therapy outcomes as well as ethical and safety considerations. Preclinical and clinical studies have shown a wide spectrum of outcomes when applying stem cells to improve cardiac function. This may reflect the infancy of clinical trials and the limited knowledge on the optimal cell type, dosing, route of administration, patient parameters and other important variables that contribute to successful stem cell therapy. Nonetheless, the field of stem cell therapeutics continues to advance at an unprecedented pace. We remain cautiously optimistic that stem cells will play a role in heart failure management in years to come.

Stem cell therapy for heart failure: Medical breakthrough, or dead end?

Postoperative atrial fibrillation (POAF) commonly occurs after coronary artery bypass graft (CABG) surgery. Patients with POAF are at higher risk of stroke and mortality. The use of oral anticoagulation (OAC) in POAF remains inconsistent, and the care gap is unknown.

The Gap in Prescribing Stroke Prevention Therapies in Postoperative Atrial Fibrillation After Isolated Coronary Artery Bypass Grafting Surgery.

A novel, wireless, ultrasound biosensor that adheres to the neck and measures real-time Doppler of the carotid artery may be a useful functional hemodynamic monitor. A unique experimental set-up during elective coronary artery bypass surgery is described as a means to compare the wearable Doppler to trans-esophageal echocardiography (TEE).

A Wireless Wearable Doppler Ultrasound Detects Changing Stroke Volume: Proof-of-Principle Comparison with Trans-Esophageal Echocardiography during Coronary Bypass Surgery.

Rony Atoui

Health Sciences North Research Institute

Continuous Venous-Arterial Doppler Ultrasound During a Preload Challenge