Christopher McIntyre

Christopher McIntyreArsh Jain

This study used advanced brain imaging and cognitive testing to examine how peritoneal dialysis affects the brain compared to the known risks of hemodialysis. Researchers found that while patients on peritoneal dialysis experienced significant increases in brain glucose levels during treatment, they did not show the acute signs of restricted blood flow or brain injury typically seen in hemodialysis patients. Despite this protective effect on brain structure, many participants still demonstrated difficulties with memory, attention, and executive function during cognitive assessments.

Christopher McIntyre

This protocol describes the design of an ongoing multicentre randomized controlled trial evaluating the impact of a 12-week intradialytic cycling program on hemodialysis-induced heart muscle stunning. Researchers will measure changes in regional wall motion abnormalities during dialysis, alongside secondary outcomes like cognitive function, recovery time, and symptom burden. The study aims to determine if exercise during dialysis can mitigate cardiac injury and improve patient-reported symptoms and functional status.

Christopher McIntyre

This review examines the technical challenges and potential errors in using bioimpedance to estimate fluid volumes in patients undergoing hemodialysis. The authors demonstrate through data simulation that standard wrist-to-ankle bioimpedance measurements tend to underestimate extracellular fluid volume as a patient's body fat percentage increases. They suggest that using segmental measurements or incorporating subject-specific body shape corrections, such as those from three-dimensional smartphone scans, can improve the accuracy of these fluid assessments.

Christopher McIntyre

This study examined whether expanded hemodialysis, which uses a specialized filter, could improve quality of life and symptom burden compared to standard hemodialysis. Over 15 months, 47 patients in Ontario, Canada, switched between standard hemodialysis and expanded hemodialysis while tracking their symptoms using a dynamic patient-reported outcomes tool. Expanded hemodialysis led to durable improvements in overall quality of life, energy, sleep, and pain, with symptoms worsening when patients switched back to standard hemodialysis.

Christopher McIntyre

Using an animal model, researchers investigated how different sodium concentrations in dialysis fluid affect blood vessel health and blood flow during hemodialysis. They found that hemodialysis itself causes acute injury to the protective lining of blood vessels and reduces blood flow, but these harmful effects were significantly worsened when a high-sodium dialysis fluid was used. This suggests that exposing patients to high sodium levels during dialysis may aggravate blood vessel damage.

Christopher McIntyre

A study of thirteen patients undergoing maintenance hemodialysis used advanced heart imaging to examine how dialysis affects blood flow to the heart muscle. Researchers found that hemodialysis reduced blood flow and caused temporary heart muscle dysfunction even in patients without coronary artery disease. In patients who did have coronary artery disease, these negative effects on heart perfusion and contraction were even more pronounced and persisted after the dialysis session ended.

Christopher McIntyreArsh Jain

Patients receiving maintenance dialysis often experience faster and more severe cognitive decline compared to those with advanced kidney disease who are not on dialysis. This review explores how both hemodialysis and peritoneal dialysis can cause structural and functional brain changes, leading to symptoms ranging from short-term confusion and brain fog to long-term loss of cognitive ability. The authors examine the underlying biological mechanisms of this decline and discuss potential medical interventions to protect brain health in this population.

Christopher McIntyre

Using a rat model of hemodialysis, researchers compared how different types of dialyzer membranes affect blood flow in tiny blood vessels. They found that conventional high-flux polysulfone dialyzers caused a twenty-five percent reduction in microvascular tissue perfusion, whereas newer mid-cut-off dialyzers preserved this blood flow. The conventional dialyzers also showed higher activation of the complement immune pathway, suggesting that dialyzer membrane design plays a key role in preventing tissue-damaging drops in blood flow during treatment.

Christopher McIntyre

This review explores the potential of advanced functional magnetic resonance imaging techniques, including multi-parametric and multi-nuclear imaging, to assess kidney function in children. These non-invasive methods can evaluate kidney perfusion, tissue oxygenation, and scarring without the need for a biopsy, and can track sodium and phosphate levels to monitor specific kidney disorders. Because these techniques do not use radiation, they are particularly well-suited for safely monitoring pediatric kidney health over time.

Christopher McIntyre

Researchers developed and tested a novel, sodium-free intraperitoneal solution containing 30% icodextrin and 10% dextrose to optimize fluid and sodium removal. In animal models and a small study of ten human patients with kidney failure, this new solution removed significantly more water and sodium than standard peritoneal dialysis solutions without causing serious adverse events or tissue damage. These findings suggest the solution could be a highly effective treatment for managing fluid overload in patients with kidney failure or other swelling disorders like heart failure.

Christopher McIntyre

This pilot study evaluated the feasibility of using sodium magnetic resonance imaging to assess residual kidney function in patients receiving hemodialysis by measuring the sodium gradient between the inner and outer parts of the kidney. Researchers found that healthy volunteers had a significantly higher sodium gradient than patients on hemodialysis, and this gradient correlated closely with urine concentration. This imaging technique may provide a new way to evaluate remaining kidney tubule function in dialysis patients, which is currently difficult to measure in clinical practice.

Christopher McIntyre

This proof-of-concept study evaluated the feasibility of using sodium magnetic resonance imaging to measure the sodium concentration within kidney cysts in four patients with autosomal dominant polycystic kidney disease. The researchers successfully captured sodium images of the kidneys, revealing a wide and previously unappreciated range of sodium content across different cysts. This imaging technique could eventually help clinicians assess the metabolic activity of cysts to improve prognosis and monitor responses to treatment without invasive procedures.

Christopher McIntyreAmit Garg

This systematic review and meta-analysis evaluated the impact of exercise during hemodialysis sessions on cardiovascular health in adults with kidney failure. Analyzing data from thirty-two studies, researchers found that intradialytic exercise, primarily aerobic, significantly reduced arterial stiffness and improved diastolic blood pressure, heart pumping function, and heart rate variability compared to standard care. These findings suggest that incorporating exercise programs during dialysis treatments can meaningfully improve several physiological measures of cardiovascular health.

Christopher McIntyre

This review examines how the circulatory stress of recurrent hemodialysis causes abnormal blood flow and progressive, irreversible damage to vital organs like the brain and heart. It explores the underlying biological mechanisms of this vascular injury and discusses potential therapeutic strategies to protect patients from these complications. Ultimately, addressing these issues is critical to reducing the high rates of cardiovascular disease and premature death in people receiving hemodialysis.

Christopher McIntyre

Researchers evaluated a new multiplex testing panel that measures 21 different proteins in blood and urine samples from healthy individuals, critically ill patients with acute kidney injury, and patients with chronic or end-stage kidney disease. They identified unique protein profiles that could accurately distinguish patients with kidney injury or disease from healthy controls, with specific markers like TIMP-1 and osteoactivin showing high predictive value. These findings demonstrate the potential of using multi-protein panels to better characterize and profile different stages of kidney dysfunction.

Christopher McIntyre

This review examines the practice of cooling dialysis fluid to prevent drop in blood pressure and protect organs like the heart and brain from stress during hemodialysis. While smaller studies previously suggested benefits, a recent large-scale trial found that a center-wide policy of using cooler dialysis fluid did not improve cardiovascular outcomes. The authors discuss why cooler dialysate may still be useful for certain individual patients rather than being completely abandoned.

Christopher McIntyre

This study evaluated whether non-invasive skin perfusion monitoring using photoplethysmography could detect hemodialysis-induced heart injury in twelve patients. Researchers found that a significant reduction in skin pulse strength during dialysis was associated with both decreased myocardial perfusion and the development of regional heart wall motion abnormalities, which indicate myocardial stunning. The findings suggest that monitoring skin perfusion is a promising, non-invasive way to detect and manage circulatory stress and heart injury during hemodialysis treatments.

Christopher McIntyre

This review highlights recent progress in sodium magnetic resonance imaging, a technology used to detect excess sodium accumulation in tissues like the skin, heart, and kidneys. Researchers have linked this tissue sodium buildup to declining kidney function, inflammation, and cardiovascular issues across the entire spectrum of chronic kidney disease. The article discusses how this imaging technique could serve as a valuable tool in future clinical trials and patient care.

Christopher McIntyre

Using advanced magnetic resonance imaging and spectroscopy during active hemodialysis sessions, researchers found direct evidence of acute brain injury in patients. The study revealed brain tissue changes consistent with swelling and chemical markers of oxygen deprivation during the period of maximum circulatory stress. These findings suggest that even a single hemodialysis session can cause acute, ischemic brain injury, which may contribute to long-term cognitive decline in this patient population.

Christopher McIntyreAndrew House

This article discusses the clinical utility of midodrine, an oral medication commonly used to prevent and treat low blood pressure during hemodialysis. While small studies show midodrine effectively raises blood pressure and improves symptoms, a large observational study raised safety concerns by linking its use to higher mortality and hospitalizations. However, these observational findings may be biased by confounding, as patients prescribed midodrine are typically sicker and at higher baseline risk for poor outcomes.

Christopher McIntyreAndrew House

This preliminary study evaluated the safety and feasibility of a novel extracorporeal immunomodulatory therapy designed to regulate white blood cells in critically ill patients with severe COVID-19. In twelve patients requiring mechanical ventilation and blood pressure support, the therapy was found to be safe and was associated with a significant 37 percent reduction in the need for blood pressure-boosting medications. These findings support further evaluation of this blood-filtering approach to manage severe inflammation in critically ill patients.

Christopher McIntyre

Patients undergoing hemodialysis experience significant circulatory stress that can damage small blood vessels and lead to organ injury, even when their overall blood pressure appears stable. This review examines various non-invasive technologies used to monitor microcirculatory function during dialysis treatments. Incorporating these monitoring tools into clinical practice could help healthcare providers detect tissue stress early and personalize dialysis delivery to improve patient outcomes.

Christopher McIntyre

Using advanced sodium magnetic resonance imaging, researchers measured tissue sodium levels in the legs of children with chronic kidney disease and compared them to healthy peers and adults. While overall tissue sodium levels did not differ significantly between healthy children and those with kidney disease, differences emerged when looking at the underlying cause of the kidney disease. Children with glomerular diseases showed elevated tissue sodium levels, whereas those with tubular disorders had reduced levels, with these measurements closely linked to protein loss in the urine and low blood albumin.

Christopher McIntyreAndrew House

The Renal Community Photo Initiative used a participatory photography method called Photovoice to explore resilience and quality of life among adult hemodialysis patients in Ontario, Canada. Participants used various photographic technologies to capture their daily lives and met in focus groups to discuss their experiences and direct how their images should be shared publicly. The project successfully gathered over 1600 images and handwritten logs, establishing a participant-led model to raise public awareness about living with chronic kidney disease.

Christopher McIntyre

This study reports on a twelve-year-old male with a rare genetic kidney disorder called hereditary hypophosphatemic rickets with hypercalciuria, which causes bone pain, fractures, and kidney calcification. Standard phosphate and potassium treatments failed to correct these issues, but adding recombinant human growth hormone, fluconazole, and dietary salt restriction successfully improved the patient's growth, bone pain, and calcium levels. Advanced sodium magnetic resonance imaging also showed normal tissue sodium levels, providing a physiological rationale for the salt restriction.

Christopher McIntyre

This study evaluated cognitive function in forty-nine patients who had recently started maintenance hemodialysis, comparing them to age- and sex-matched healthy controls. Researchers found that a high proportion of patients experienced cognitive impairment within their first year of starting dialysis, with the most significant deficits observed in verbal skills and reasoning. These findings suggest that cognitive decline is highly prevalent early in the course of hemodialysis and may be related to the treatment itself.

Christopher McIntyreAmit Garg

This study explored the barriers and enablers to delivering exercise programs during dialysis treatments by interviewing healthcare providers and patients across twelve hospitals in Ontario, Canada. The researchers identified key challenges, including a lack of staff training, concerns about workload, and uncertainty regarding patient eligibility and safety. To address these issues, they developed a list of practical solutions and a forty-seven-item feasibility checklist to help clinics successfully implement exercise programs in dialysis units.

Christopher McIntyreAndrew House

This study evaluated the ability of sodium magnetic resonance imaging to measure the sodium concentration gradient between the inner and outer parts of the kidney, which is a key indicator of kidney function. In healthy volunteers, changes in this gradient measured by the scan closely matched changes in urine concentration after drinking water, and the imaging technique was also shown to be feasible in patients with chronic kidney disease. This non-invasive imaging method could provide a new way to monitor kidney health and function without relying solely on urine tests.

Christopher McIntyre

Using advanced sodium magnetic resonance imaging, researchers measured the concentration of sodium in the skin of patients undergoing hemodialysis and peritoneal dialysis. They found that higher levels of skin sodium were strongly linked to a higher risk of death and major cardiovascular events, independent of age, sex, and blood sodium levels. In hemodialysis patients, higher skin sodium was specifically associated with the sodium concentration of the dialysis fluid, low blood albumin, and a history of congestive heart failure.

Christopher McIntyre

Using a newly developed small animal model, researchers monitored the microvasculature of healthy rats in real time during hemodialysis. They found that even without fluid removal, the hemodialysis procedure caused significant systemic hemodynamic disturbances and acutely reduced blood flow in skeletal muscle microcirculation. This model demonstrates that hemodialysis itself can directly impair microvascular perfusion, providing a new way to study and prevent dialysis-induced ischemic organ injury.

Louise MoistChristopher McIntyre

Researchers followed eight patients undergoing hemodialysis through the creation of an upper-arm arteriovenous fistula and tracked changes in their heart structure using magnetic resonance imaging. They found that all patients experienced an increase in the muscle mass of the heart's main pumping chamber, and most experienced a decrease in the chamber’s ability to pump blood effectively within the first year. These changes in heart structure are concerning because increased heart muscle mass is linked to a higher risk of health problems and death in people with kidney disease.