2 Clinical Trials for Various Conditions
Patients undergoing liver transplantation (LT) have a high risk for cardiovascular disease (CVD). Frailty is a frequent condition among LT candidates. Together, CVD and frailty are major causes of morbidity and mortality before and after LT. Conventional methods to diagnose and predict CVD in LT candidates lack sensitivity and clinically relevant application. However, cardiopulmonary exercise testing (CPET) can directly estimate coronary artery disease, cirrhotic cardiomyopathy, and indirectly assess frailty. Such versatility of CPET has caused it to become the standard of care in many LT centers outside of the United States. In preliminary work (funded internally by the Pittsburgh Liver Research Center) that will be used to fund a more definitive study (RO1), the investigators plan to investigate CVD and frailty in LT candidates, both from existing standard of care (SOC) methods and CPET. The investigators expect results to improve the current capacity to assess and prognosticate CVD and frailty in LT, ultimately changing practice.
The rapid rise in obesity (body mass index (BMI) ≥ 30 kg/m2) in the US over the past decade is responsible for more disease and death than any other single factor. Severe obesity is associated with numerous co-morbidities contributing to increased mortality risk, including end stage liver disease. Liver transplantation is a life-saving procedure for patients with end stage liver disease and obesity is becoming increasingly prevalent in this population. In one study, 54% of patients undergoing orthotopic liver transplant (OLT) were either overweight or obese \[body mass index (BMI) \>25 kg/m2\], and 7% were severely or morbidly obese (BMI \> 35 kg/m2). In addition, weight gain after solid organ transplantation is common because of steroid-containing immunosuppression and physical inactivity from decreased exercise tolerance. Obesity has been shown to increase the surgical morbidity, including wound infections, wound dehiscence, and hernias after transplantation. More significantly, excess pretransplant body weight hinders the rate of improvement in health-related quality of life after liver transplantation\[7\]. One possible approach for treating obesity after a liver transplant is to use bariatric surgery. Currently, bariatric surgery is established as the most effective means for both weight loss and resolution of metabolic disease in the morbidly obese. Recent publications emphasize the usefulness of bariatric surgery in the reduction of long-term cardiometabolic risk, cardiovascular disease incidence and mortality, and the management of uncontrolled type 2 diabetes (T2DM). In addition, it decreases mortality and improves both social functioning and quality of life. Bariatric surgery may improve eligibility for transplant in patients previously excluded due to excessive weight. Bariatric procedures, such as sleeve gastrectomy, allow for significant weight loss over time that greatly reduces or eliminates obesity related illnesses such as diabetes, high blood pressure and liver disease. According to the National Institutes of Health, bariatric surgery is reserved for patients with a BMI of \> 40 or \> 35 kg/m2 in the presence of major co-morbidities (e.g. type 2 diabetes, hypertension, sleep apnea, heart disease, etc). A significant number of liver transplant candidates have obesity-related illnesses, thus putting them at risk for cardiovascular and metabolic complications post-transplant. In addition, patients awaiting OLT are typically no longer medically stable to undergo intensive diet and exercise regimens as treatment for their diseases. Finally, decreased activity and medications used to prevent liver graft rejection all contribute to increased weight gain following transplant. In fact, in a series of 320 non-obese liver transplant recipients, 21.6% of patients became obese within two years of transplant. These comorbidities also contribute to poorer post-transplant outcomes and development of what is known as the post-transplant metabolic syndrome. Morbidly obese patients (BMI \> 40 kg/m2) may also have higher frequencies of morbidities such as prolonged hospitalization and readmission as well as infectious, wound, and cardiovascular complications after transplantation. Finally, intra-abdominal adiposity creates a technically more challenging operative dissection, but no data exist on whether it increases perioperative morbidity or mortality in liver transplant patients. Sleeve gastrectomy is the most attractive restrictive procedure in a liver transplant population for several key reasons. One, sleeve gastrectomy does not require the implantation of a foreign body, such as placement of an adjustable gastric band, which in an immunocompromised post-transplant patient raises concern for severe infectious complications. Secondly, as stated previously, sleeve gastrectomy is a purely restrictive procedure, and therefore is least likely to cause significant macronutrient and micronutrient deficiencies. Finally, when compared to other restrictive procedures, such as adjustable gastric band placement, it has a lower likelihood of treatment failure (i.e. \<50% excess weight loss). In fact, recent reports describe not only high failure rates with adjustable gastric band placement, but also high reintervention rates for both band-related complications (e.g. band erosion, leakage, slippage, port infection and esophageal dilatation) and failure to lose weight such that as few as 54% of patients may have their band in place after 10 years.