Efficacy And Mechanisms Of Exercise Training In Diastolic Heart Failure
Funder
National Health and Medical Research Council
Funding Amount
$385,250.00
Summary
Heart failure is modern epidemic which presents a significant public health burden, due to a high mortality, frequent hospital admissions and impaired functional capacity. Although the typical heart failure patient presents with a reduced contractile function, many patients have typical heart failure symptoms but with normal contraction. The problem in these patients seems to relate to the heart's ability to fill with blood, and this entity is known as diastolic heart failure (DHF). This syndrom ....Heart failure is modern epidemic which presents a significant public health burden, due to a high mortality, frequent hospital admissions and impaired functional capacity. Although the typical heart failure patient presents with a reduced contractile function, many patients have typical heart failure symptoms but with normal contraction. The problem in these patients seems to relate to the heart's ability to fill with blood, and this entity is known as diastolic heart failure (DHF). This syndrome is most frequently due to ischemic or hypertensive heart disease, and most commonly occurs in the elderly. The optimal management of DHF is not well defined, although some drug trials are currently in progress. A number of studies have shown exercise training to improve functional capacity by 15-20% in typical heart failure. However, training has not so far been trialled in DHF. In this multicenter, multi-disciplinary study, we will study a training and control group to determine whether exercise capacity and DHF symptoms are responsive to exercise training. This work will teach us about the optimum exercise prescription, in terms of the duration and nature of training, as well as the safety and effectiveness of exercise training. By using a number of sensitive measurements of heart and vessel function (in which our group has special expertise), we will identify whether exercise training exerts its effect through improvement in vascular function and myocardial properties. If successful, the clinical implications of this study are that; 1. Exercise training will be adopted to improve functional capacity and symptoms of DHF 2. The merits of aerobic and strength training will be identified in DHF 3. Abnormal blood vessel function will be identified as a major and reversible contributor to DHFRead moreRead less
Exertional Dyspnoea With Increased Filling Pressure - Mechanisms And Treatment Strategies
Funder
National Health and Medical Research Council
Funding Amount
$387,793.00
Summary
Patients with early heart disease often present with shortness of breath with exercise, as myocardial reserve at that stage is usually sufficient to maintain normal function at rest . Indeed, much myocardial dysfunction may originate from the modern lifestyle, including inactivity, obesity, the metabolic syndrome and type II diabetes. The potential benefits of making a definitive early diagnosis are large, because it seems more likely that an impact can be made on the disease process (and theref ....Patients with early heart disease often present with shortness of breath with exercise, as myocardial reserve at that stage is usually sufficient to maintain normal function at rest . Indeed, much myocardial dysfunction may originate from the modern lifestyle, including inactivity, obesity, the metabolic syndrome and type II diabetes. The potential benefits of making a definitive early diagnosis are large, because it seems more likely that an impact can be made on the disease process (and therefore, outcome) than with late stage disease. Current treatment strategies are expensive and because they are directed at end-organ damage (heart failure, heart attacks etc), rather ineffective. This multispecialty, multidisciplinary group will undertake a series of unique studies aimed at identifying early cardiovascular disease. The strategy will involve detection of abnormal filling behaviour at stress echocardiography, with randomization into longterm and short-term trials to examine various therapeutic strategies. Sensitive new cardiovascular imaging techniques will be used to detect preclinical abnormalities in the structure and function of the heart and vasculature, facilitating a mechanistic understanding of the process of increasing filling pressure with exercise.Read moreRead less
Importance Of The Transmural Distribution Of Viable Myocardium To Outcome Of Patients After Revascularization
Funder
National Health and Medical Research Council
Funding Amount
$268,800.00
Summary
After a heart attack, up to 50% of tissue showing reduced function can recover if blood supply is returned to normal with bypass surgery or balloon angioplasty. Because these procedures may be risky in cardiac patients, the investigators have used various imaging approaches including radionuclide and ultrasound techniques to predict regions where function will recover after intervention. The results of these tests may be discordant because they assess separate attributes of cardiac muscle, and s ....After a heart attack, up to 50% of tissue showing reduced function can recover if blood supply is returned to normal with bypass surgery or balloon angioplasty. Because these procedures may be risky in cardiac patients, the investigators have used various imaging approaches including radionuclide and ultrasound techniques to predict regions where function will recover after intervention. The results of these tests may be discordant because they assess separate attributes of cardiac muscle, and selection of patients for intervention on the basis of recovery of regional function ignores some other aspects that may be important. These include avoidance of heart enlargement, improvement of exercise capacity, and avoidance of heart rhythm disturbances and even other heart attacks. In this study, the investigators seek to define the importance of the proportion and site of live (viable) myocardium to the parameters listed above. A new magnetic resonance technique will be used to identify whether radionuclide and ultrasound techniques assess different parts of the heart wall. The relative importance of these sites will be identified by comparing the outcome of patients who have live tissue in the inner half, compared with the outer half of the heart wall. This study will involve 180 patients who will undergo testing with magnetic resonance and radionuclide imaging. A subgroup will undergo dobutamine echocardiography. Their responses over follow-up will be assessed by accurate evaluation of heart size, exercise response, heart rhythm abnormalities and clinical events.Read moreRead less
STudy Of Risk Assessment To Reduce Complications In Patients Following Noncardiac SurgerY (STRATIFY)
Funder
National Health and Medical Research Council
Funding Amount
$436,000.00
Summary
Cardiac problems account for many complications in patients undergoing major non-cardiac surgery, and even apparently minor cardiac damage is a marker of high risk for subsequent adverse events. Unfortunately, while money and effort is expended on identifying patients at risk, the appropriate response to this risk is quite unclear. The performance of bypass surgery or balloon angioplasty in order to treat the underlying coronary disease of at-risk patients is used in other situations, and reduce ....Cardiac problems account for many complications in patients undergoing major non-cardiac surgery, and even apparently minor cardiac damage is a marker of high risk for subsequent adverse events. Unfortunately, while money and effort is expended on identifying patients at risk, the appropriate response to this risk is quite unclear. The performance of bypass surgery or balloon angioplasty in order to treat the underlying coronary disease of at-risk patients is used in other situations, and reduces longterm risk. However, in many patients undergoing major noncardiac surgery, this approach may be inappropriately aggressive, as these patients are often elderly, have other diseases that make heart operations more difficult and risky than usual, and in any case may have a reduced life expectancy from the disease necessitating the operation. As the most critical issue is to ensure that patients undergo their surgery uneventfully, an alternative is the use of intensive medical therapy to protect the heart. This multicentre study, based at Brisbane hospitals that perform large numbers of major operations, will follow up patients for complications, and outcome (including quality of life) will be assessed six months after the operation. We will address two important questions about the efficacy and cost of risk reduction strategies. First, in patients at higher levels of risk and with a positive stress test, could a combination of medical therapy designed to protect the heart be as effective as current approaches, which include the performance of bypass surgery or coronary balloon angioplasty? Second, in patients identified as being at some risk - but low risk - are drugs sufficiently effective to avoid the need for further testing to quantify risk? As the population continues to age, the numbers of at risk patients undergoing major surgery will increase, and answers to these questions will provide important information to guide their management.Read moreRead less
This Study aims to answer the question: When is the best time for adults with kidney disease to start dialysis? This question is currently a subject of intense international debate. It has been suggested that patients who commence dialysis relatively early, when they still have a high level of remaining kidney function, have fewer complications, maintain a better level of function in the community and are less likely to die as a result of their kidney disease. However, this has not been determin ....This Study aims to answer the question: When is the best time for adults with kidney disease to start dialysis? This question is currently a subject of intense international debate. It has been suggested that patients who commence dialysis relatively early, when they still have a high level of remaining kidney function, have fewer complications, maintain a better level of function in the community and are less likely to die as a result of their kidney disease. However, this has not been determined in a rigorous scientific manner. In fact starting dialysis earlier may expose the person to the risks associated with the use of dialysis and may also impact on their quality of life. Many international kidney societies have formulated guidelines recommending that dialysis should be commenced early - when the remaining kidney function drops to a level of approximately 10-15% of normal kidney function. Recent practice in Australia and New Zealand has been to commence dialysis when the remaining kidney function is between 6 and 9% of normal. Hence, the adoption of these guidelines recommending an earlier dialysis start time will have a significant impact on health costs; therefore a net benefit to the patient and the community, needs to be demonstrated. To answer this important question, we have designed and instituted a multi-center trial, that was commenced in 2000. The trial has been scientifically designed (randomised controlled trial) to compare the effect of early start dialysis (remaining kidney function between 10-14%) versus late start dialysis (remaining kidney function between 5-7%) on survival, disease and dialysis complications and subsequent hospitalization. To date 748 of the required 800 patients have been entered into the trial and will be followed for a minimum of 3 years. We are confident the results of this trial will impact at a local, national and international level, delineating best practice management of dialysis in people with kidney failure.Read moreRead less
The outcomes to be assessed are recurrent ischaemic stroke, intracranial haemorrhage, myocardial infarction, parenchymal embolism and vascular death. Should these outcomes be significantly reduced, the public health and economic issues which will be addressed in this study are considerable. Approximately 40,000 new and recurrent cases of stroke occur in Australia each year, and about 80% of these are ischaemic. There is an average prevalence of about 20% of large or complex aortic plaque among p ....The outcomes to be assessed are recurrent ischaemic stroke, intracranial haemorrhage, myocardial infarction, parenchymal embolism and vascular death. Should these outcomes be significantly reduced, the public health and economic issues which will be addressed in this study are considerable. Approximately 40,000 new and recurrent cases of stroke occur in Australia each year, and about 80% of these are ischaemic. There is an average prevalence of about 20% of large or complex aortic plaque among patients with ischaemic stroke. About the same proportion of cases of ischaemic stroke yearly are associated with the presence of complex aortic plaque alone, and as many again with simple plaque (40% in total). Using the NHMRC estimated cost of $40,000 per stroke (and assuming that recurrent stroke costs are similar to initial stroke costs) and the estimated recurrent stroke rates of 11.9-100 person-years for plaque > 4 mm, the national cost of recurrent ischaemic stroke attributable to complex aortic plaque alone is about $3 million in the first year. This estimate does not include patients with incident TIA and atherosclerotic plaque or the resources spent on evaluating recurrent stroke and TIA attributable to aortic plaque, the cost of lost wages, or the negative impact on the quality of life of the victims. The economic and public health burden to our society could be greatly reduced by successful efforts at secondary stroke prevention in individuals with aortic plaque and TIA or ischaemic stroke. If just 25% of recurrent ischaemic strokes associated with aortic arch debris could be prevented by treatment interventions, the annual savings to society for recurrent ischaemic stroke alone would be considerable.Read moreRead less