Christopher D. Blosser

Global Cardiovascular and Renal Outcomes of Reduced GFR

The burden of premature death and health loss from ESRD is well described. Less is known regarding the burden of cardiovascular disease attributable to reduced GFR. We estimated the prevalence of reduced GFR categories 3, 4, and 5 (not on RRT) for 188 countries at six time points from 1990 to 2013. Relative risks of cardiovascular outcomes by three categories of reduced GFR were calculated by pooled random effects meta-analysis. Results are presented as deaths for outcomes of cardiovascular disease and ESRD and as disability-adjusted life years for outcomes of cardiovascular disease, GFR categories 3, 4, and 5, and ESRD. In 2013, reduced GFR was associated with 4% of deaths worldwide, or 2.2 million deaths (95% uncertainty interval [95% UI], 2.0 to 2.4 million). More than half of these attributable deaths were cardiovascular deaths (1.2 million; 95% UI, 1.1 to 1.4 million), whereas 0.96 million (95% UI, 0.81 to 1.0 million) were ESRD-related deaths. Compared with metabolic risk factors, reduced GFR ranked below high systolic BP, high body mass index, and high fasting plasma glucose, and similarly with high total cholesterol as a risk factor for disability-adjusted life years in both developed and developing world regions. In conclusion, by 2013, cardiovascular deaths attributed to reduced GFR outnumbered ESRD deaths throughout the world. Studies are needed to evaluate the benefit of early detection of CKD and treatment to decrease these deaths.

Plasma C4d+ Endothelial Microvesicles Increase in Acute Antibody-mediated Rejection.

Background Antibody-mediated rejection (AMR) is a major cause of kidney allograft loss. Currently, AMR diagnosis relies on biopsy which is an invasive procedure. A noninvasive biomarker of acute AMR could lead to early diagnosis and treatment of this condition and improve allograft outcome. Microvesicles are membrane-bound vesicles released from the cell surface after injury. We hypothesized that because AMR is associated with allograft endothelial injury and C4d deposition, plasma microvesicles positive for endothelial (CD144) marker and C4d are increased in this condition. Methods We studied microvesicle concentration in the plasma of 95 kidney transplant patients with allograft dysfunction and compared with 23 healthy volunteers. Biopsy diagnosis and scoring was performed using Banff classification. Results In the 28 subjects with AMR, the density of C4d+/CD144+ microvesicles was on average 11-fold (P = 0.002) higher than transplant recipients with no AMR and 24-fold (P = 0.008) than healthy volunteers. Densities of C4d+ and C4d+/annexin V+ (C4d+/AVB+) microvesicles were also increased in AMR patients compared with no AMR and healthy subjects. C4d+/AVB+ microvesicles correlated with AMR biopsy severity. Nine patients with acute AMR that received treatment showed a mean 72% decrease (P = 0.01) in C4d+/CD144+ microvesicle concentration compared with pretreatment values. Conclusions Quantification of plasma C4d+ microvesicles provides information about presence of AMR, its severity and response to treatment in transplant patients.

Mistaken identity: normotensive scleroderma renal crisis

A patient presented with neuromuscular, respiratory and cardiac symptoms and was initially diagnosed with amyotrophic lateral sclerosis (ALS), myocardial ischaemia and pneumonia. He developed unexplained progressive kidney failure over the ensuing week, and his kidney biopsy showed thrombotic microangiopathy that led to the correct diagnosis of normotensive scleroderma renal crisis. His clinical presentation and course were consistent with systemic sclerosis and normotensive scleroderma renal crisis. He was treated with an ACE inhibitor (ACEi) and haemodialysis with significant functional improvement over the next 3 months to his prior baseline with the exception of kidney failure. This case highlights a diagnostic challenge requiring astute history and physical examination skills, and the value of a kidney biopsy in providing the final diagnosis.