RESUMO
A comprehensive review of relevant clinical literature on evidence-based recommendations and existing prediction models specific to lung cancer surgery was undertaken. Preoperative risk assessment parameters such as pulmonary function tests (PFT), cardiopulmonary exercise testing (CPET), Brunelli models, Thoracoscore and frailty were analyzed for predicting postoperative risk of complications. When assessing fitness for surgery, the primarily used PFT parameters such as predictive postoperative forced expiratory volume in one second (FEV1) and diffusion capacity for carbon monoxide (DLCO ) showed conflicting evidence in determining a positive correlation with postoperative mortality. CPET variables predicted higher complication risk when VO2peak < 10ml/kg/min, AT < 11ml/kg/min and ventilation/carbon dioxide production (VE/VCO2) was in range of 34-40. While a cardiac risk index like the Thoracic Revised Cardiac Risk Index (ThRCRI) predicted major cardiovascular compromise, a thoracic risk index like Thoracoscore proved imprecise. Lastly, frailty is used to risk stratify patients in clinical practice but a recognized validated model specific to thoracic surgery is non-existent. When considering patients for lung cancer surgery, some dilemma exists regarding the accuracy of clinical prediction models and their external validation. There is a pressing need for the development of a consolidated clinically robust risk stratification model to predict complications after thoracic resections.
RESUMO
High-output cardiac failure is a rare form of heart failure associated with the formation of arteriovenous fistula (AVF) in hemodialysis patients. The pathophysiology underlying the HOCF is complex and multifactorial. Presence of AVF can cause long term hemodynamic changes that ultimately lead to increased cardiac output and consequently cardiac failure. A number of risk factors have been associated with the development of HOCF post-AVF construction, including male sex, a proximally located AVF and a state of volume overload. Dysregulation of tissue inhibitor of matrix metalloproteinase 4, Sirtuin-1 and Sirtuin-3 gene expression have been associated with the development of heart failure. The differences observed between genders have been attributed to altered activity of the ß-adrenoceptor system. Numerous biomarkers including cardiac troponin T and I, atrial natriuretic peptide, brain natriuretic peptide among others have shown both prognostic and diagnostic potential; however further research is needed to establish their utility in clinical practice for patients with AVF associated HOCF. In recent years risk stratification models have been developed to help identify patients at the highest risk of developing HOCF post AVF which could be revolutionary in its identification and management. Potential options for managing HOCF post-AVF include AVF ligation, banding and anastoplasty however these procedures are not without their own associated risks. In this review, we discuss the pathophysiology, risk stratification and management of patients with AVF associated HOCF.
