From the Guidelines
Yes, acute kidney injury (AKI) can cause high blood pressure due to the kidneys' reduced ability to filter excess fluid and sodium from the blood, leading to fluid retention and increased blood volume. When the kidneys are injured, they may not effectively filter excess fluid and sodium from the blood, leading to fluid retention and increased blood volume. This puts additional pressure on blood vessel walls, resulting in elevated blood pressure. Additionally, the damaged kidneys might release hormones like renin that trigger the renin-angiotensin-aldosterone system, further constricting blood vessels and raising blood pressure 1.
Some key points to consider in the management of high blood pressure in the context of AKI include:
- The importance of timely identification and treatment of AKI to prevent progressive kidney disease and other poor health outcomes 1
- The role of ACE inhibitors and ARBs in managing blood pressure and reducing the risk of progressive kidney disease, even in patients with reduced kidney function 1
- The need for careful fluid management, which may include restricting salt and fluid intake or using diuretics if fluid overload is present 1
- The importance of monitoring blood pressure regularly during AKI recovery, as it often improves as kidney function returns to normal 1
It is also important to note that some patients may develop chronic kidney disease following AKI, which could lead to long-term hypertension requiring ongoing management 1. In such cases, treatment typically focuses on addressing the underlying cause of AKI while managing blood pressure with medications such as ACE inhibitors, ARBs, or calcium channel blockers as appropriate.
In terms of specific management strategies, the use of ACE inhibitors or ARBs is recommended as first-line therapy for hypertension in patients with diabetes and established coronary artery disease 1. Additionally, the combination of an ACE inhibitor and an ARB should be avoided due to the reported harms demonstrated in several large cardiology trials 1.
Overall, the management of high blood pressure in the context of AKI requires a comprehensive approach that takes into account the underlying cause of AKI, the patient's kidney function, and the need for careful fluid management and regular blood pressure monitoring. The goal of treatment should be to reduce blood pressure to a target of <130/80 mm Hg, while also addressing the underlying cause of AKI and preventing progressive kidney disease 1.
From the Research
Relationship Between Blood Pressure and Acute Kidney Injury (AKI)
- High blood pressure can be a result of acute kidney injury (AKI) as indicated by a study published in 2019 2, which found that the prevalence of hypertension was 70% in patients with AKI.
- The study also noted that the prevalence of hypertension varied depending on the origin of AKI, with post-renal AKI having the highest rate of hypertension at 85%, followed by renal AKI at 75%, and pre-renal AKI at 30% 2.
- Another study published in 2017 3 suggested that mean arterial pressure (MAP) may not be an adequate target in AKI, and that other factors such as diastolic arterial perfusion and diastolic perfusion pressures may play a role in the progression of AKI.
Impact of Angiotensin-Converting Enzyme Inhibitors (ACEIs) and Angiotensin II Receptor Blockers (ARBs) on Blood Pressure in AKI
- A study published in 2022 4 found that the use of ACEIs/ARBs in patients with AKI was associated with a decreased risk of mortality, but an increased risk of acute kidney disease (AKD).
- Another study published in 2021 5 found that exposure to ACEIs/ARBs after AKI was associated with lower risks of all-cause mortality, recurrent AKI, and progression to incident chronic kidney disease (CKD).
- However, the same study noted that the use of ACEIs/ARBs was also associated with a higher risk of hyperkalemia, highlighting the need for close clinical monitoring 5.
- A study published in 2021 6 found that the risk of AKI in emergency medical admissions was higher among users of ACEIs/ARBs at target or above target dosages, suggesting that physicians should adjust RAS blockade according to estimated glomerular filtration rate (eGFR) and advise patients to withhold ACEIs/ARBs in cases of acute illness.