Plasma exchange therapy may boost short-term survival in AAV
China study: Patients with poor kidney function could see benefits
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Adding plasma exchange, a blood-cleaning procedure, to standard therapy to induce disease remission may help reduce short-term mortality in people with ANCA-associated vasculitis (AAV) with poor kidney function, a study in China shows.
Still, mortality rates at one year were comparable between patients who received plasma exchange and those who didn’t. In addition, the procedure was associated with significantly higher rates of infection.
This study shows “that the clinical application of [plasma exchange] requires a balance between its early survival benefits and infection risks, and should be individualized for the patients who are most likely to benefit,” researchers wrote.
The study, “Efficacy and safety of plasma exchange for crescentic and mixed classes of ANCA-associated glomerulonephritis with renal insufficiency,” was published in BMC Nephrology.
Kidney involvement common in AAV
AAV refers to a group of diseases characterized by inflammation and damage to small blood vessels, usually caused by self-reactive antibodies called ANCAs. Kidney involvement is common, often presenting as glomerulonephritis, or inflammation in the filtering units of the kidneys, called glomeruli.
Glomerulonephritis may be classified as focal, in which most glomeruli look normal; crescentic, when most glomeruli present crescent-shaped scar tissue; sclerotic, when most glomeruli are scarred and hardened; or a mixed profile of features of more than one class.
Plasma exchange consists of removing a patient’s plasma, the liquid portion of blood, and replacing it with plasma from a healthy donor to help remove AAV-driving antibodies. While some studies have reported that the procedure improves kidney function and reduces the risk of kidney failure, others have found no significant benefits.
3-month mortality lower among plasma exchange-treated patients
In this study, a team of researchers in China set out to evaluate whether adding plasma exchange to standard induction treatment improved survival in AAV patients with poor kidney function and crescentic or mixed glomerulonephritis, for which the procedure’s benefits are less certain.
They retrospectively analyzed data from 61 patients, most of whom were men (54.1%), with a mean age of 58.4 years. Almost two-thirds had mixed class glomerulonephritis (62.3%), while the remaining 37.7% had crescentic class.
A total of 30 patients received a standard induction regimen with the corticosteroid methylprednisolone plus cyclophosphamide or mycophenolate mofetil (two immunosuppressive therapies), while 31 received standard treatment plus plasma exchange.
Participants who received plasma exchange were significantly more likely to have alveolar hemorrhage, or bleeding into the lung’s air sacs due to damaged small lung blood vessels, at treatment start compared with those who received standard therapy alone (35.5% vs. 10%).
The plasma exchange group was also significantly more commonly treated with high-dose, short-term methylprednisolone (93.5% vs. 63.3%) and cyclophosphamide (93.5% vs. 66.7%), and less frequently with mycophenolate mofetil (3.2% vs. 20%). They also received a significantly higher cumulative dose of methylprednisolone (13.2 g vs. 4.9 g).
Mortality was lower among patients treated with plasma exchange after three months (9.7% vs. 40%) and one year (25.8% vs. 50%), but differences only reached statistical significance in the short term.
[Plasmapheresis] plus standard induction therapy improved short-term survival at [three] months in patients with crescentic and mixed ANCA-associated glomerulonephritis. However, it did not improve the dialysis independence … and was associated with a higher risk of infection.
There were no significant differences in the need for dialysis, a procedure to filter waste and excess fluid from the blood when the kidneys can no longer perform this role, between the two groups of patients.
“The rapid removal of ANCA[s] may have accounted, in part, for the decline of short-term mortality in our study,” the researchers wrote.
Further statistical analysis revealed that plasma exchange was significantly associated with a lower risk of a combined event of death or kidney failure, by 80.6% after three months and 62.7% after one year. This association remained after adjusting for several potential influencing factors, including patients’ age, sex, alveolar hemorrhage, kidney function, AAV activity, and treatment.
The most frequently reported adverse events were infections (45.9%), particularly pneumonia, a lung infection (39.3%). Infections were significantly more common in patients treated with plasmapheresis than in those who weren’t (61.3% vs. 30%).
“[Plasmapheresis] plus standard induction therapy improved short-term survival at [three] months in patients with crescentic and mixed ANCA-associated glomerulonephritis,” the researchers wrote. “However, it did not improve the dialysis independence … and was associated with a higher risk of infection.”
