Thrombotic microangiopathy in patients with malignant hypertension

Abstract

Background Thrombotic microangiopathy (TMA) is a complication of malignant hypertension (mHTN) attributed to the high levels of blood pressure (BP). However, no studies have investigated in patients with mHTN of different etiologies whether the presence of TMA is associated with specific causes of mHTN. Methods We investigate the presence of TMA (microangiopathic hemolytic anemia and thrombocytopenia) in a large and well characterized cohort of 199 patients with mHTN of different etiologies (primary HTN 44%, glomerular diseases 16.6%, primary atypical hemolytic uremic syndrome (aHUS) 13.1%, renovascular HTN 9.5%, drug-related HTN 7%, systemic diseases 5.5%, endocrine diseases 4.5%). Outcomes of the study were kidney recovery and kidney failure. Results Patients with TMA (40 cases, 20.1%) were younger, had a lower proportion of males, lower BP levels and worse kidney function at presentation. Their underlying diseases were primary aHUS (60%), drug-related mHTN (15%), glomerular diseases (all of them IgA nephropathy) (10%), systemic diseases (10%) and primary HTN (5%). The presence of TMA was 92.3% in primary aHUS, 42.9% in drug-related HTN, 36.4% in systemic diseases, 12.1% in glomerular diseases and 2.3% in primary HTN. No patient with renovascular HTN or mHTN caused by endocrine diseases developed TMA, despite BP levels as severe as patients with TMA. A higher proportion of TMA patients developed kidney failure as compared to patients without TMA (56.4% versus 38.9%, respectively). Conclusions The presence of TMA in patients with mHTN should guide the diagnosis towards primary aHUS, drug-related mHTN, some systemic diseases and IgA nephropathy, while it is exceptional in other causes of mHTN.

A Renal Disease Triggered by COVID-19

“…However, our patient was clinically stable before this HUS episode and had normal blood pressure recorded during outpatient follow-up. 14 Genetic predisposition, namely, mutations in AC regulation, is common in patients with aHUS. Determining the underlying mutation with genetic testing is warranted, if possible, even if there are known triggers.…”

“…However, our patient was clinically stable before this HUS episode and had normal blood pressure recorded during outpatient follow-up. 14…”

Persistently elevated sFlt-1 and recovery of reduced ADAMTS13 activity in malignant hypertension

“…Moderately reduced ADAMTS13 activity may suggest a thrombotic tendency in hypertensive emergency, which was indicated by higher levels of Fg in patients with MHT. In addition, further evaluation of specific causes, such as atypical hemolytic uremic syndrome, should be performed in acute hypertensive patients with TMA [27,28]. The severity of decreasing plasma ADAMTS13 activity may help in the differential diagnosis between MHT and hypertensive crisis.…”

Targeting complement in IgA nephropathy

“…Since TMA and vascular lesions are not included in the Oxford pathologic classification, there is a lack of systematic report and analysis of these lesions in IgAN, but they seem to be similar to those found in other causes of TMA [ 47 ]. Despite the relatively high prevalence of TMA in IgAN, the percentage of patients presenting laboratory evidence of TMA (microangiopathic hemolytic anemia, thrombocytopenia, elevated lactate dehydrogenase, decreased or undetectable serum haptoglobin, schistocytes in peripheral blood smear) seems to be low compared with other entities causing TMA [ 56 ], and the reason for this discrepancy is not clear.…”