What is the treatment for renal (kidney) infarction?

From the Guidelines

The treatment of renal infarct should prioritize selective angioembolization (AE) as the primary intervention for hemodynamically stable patients with indications such as arterial contrast extravasation on CT-scan, gross non-self-limiting hematuria, arteriovenous fistula, pseudoaneurysm, extended perirenal hematoma, and progressive decrease in hemoglobin concentration. This approach is supported by the most recent and highest quality study available, which suggests that AE has a high success rate, ranging from 63% to 100%, and is associated with better outcomes in terms of renal function and ICU length of stay compared to nephrectomy 1.

Key Considerations for Treatment

• Indications for angiography and eventual selective angioembolization include arterial contrast extravasation on CT-scan, gross non-self-limiting hematuria, arteriovenous fistula, pseudoaneurysm, extended perirenal hematoma, and progressive decrease in hemoglobin concentration.
• The success rate of AE in blunt renal trauma is high, and re-interventions are justified when indicated by the clinical course.
• AE seems to have better results in terms of renal function and ICU length of stay compared with nephrectomy, showing similar transfusion need and re-bleeding rates.
• The anatomical damage to the kidney is associated with the need to repeat AE, but not with an overall AE failure.

Management Approach

• Selective angioembolization should be performed as sub-selectively as possible to limit the associated parenchymal infarction.
• Agents used for AE can induce either temporary or permanent arterial occlusion, and the chosen embolic agents depend on the type of vascular injury.
• Embolization should be considered for patients with severe trauma and liable hemodynamic parameters, provided that the environment is adequate and risk is not increased.
• Conservative management of main renal artery occlusion leads to a high rate of severe hypertension, requiring subsequent nephrectomy, while percutaneous revascularization with stents showed better outcomes on renal function than surgical treatment.

Important Considerations

• Renal venous pedicle avulsion is a contraindication for non-operative management (NOM) and AE, and requires immediate surgery.
• Warm ischemia time longer than 60 minutes leads to significant exponential losses in kidney function, and the placement of a peripheral stent graft may be considered for hemostasis, allowing perfusion of the renal artery distal to the injury site.
• Selective balloon occlusion can be considered as a temporary bleeding control maneuver prior to laparotomy, however, fluoroscopy is required for positioning of the guidewire and balloon catheter.

From the Research

Treatment of Renal Infarct

• The treatment of renal infarct is a complex process, and there is no generally accepted protocol for its diagnosis and treatment 2.
• Renal replacement therapy (RRT) may be required in some cases, with continuous renal replacement therapies (CRRT) being the preferred technique 3.
• Anticoagulation therapy is often used in the treatment of renal infarct, with unfractionated heparin being the most widely used anticoagulant 3, 4.
• However, anticoagulation therapy can be associated with significant adverse effects, including bleeding complications and heparin-induced thrombocytopenia (HIT-II) 3, 5, 6.
• Regional citrate anticoagulation (RCA) is a safe and effective technique that can be used as an alternative to systemic anticoagulation 3, 4.
• The choice of anticoagulant for CRRT should be determined by patient characteristics, local expertise, and ease of monitoring 4.
• Surgical treatment is effective only in the first hours after the onset of renal infarct, and the outcome is often unfavorable with a high probability of hemorrhagic complications 2.

Anticoagulation Strategies

• The most common anticoagulant options for CRRT include unfractionated heparin (UFH), regional citrate anticoagulation (RCA), and no anticoagulation 4.
• The Kidney Disease Improving Global Outcomes (KDIGO) acute kidney injury guidelines recommend using RCA rather than UFH in patients who do not have contraindications to citrate and are with or without increased risk of bleeding 4.
• Monitoring should include evaluation of the anticoagulant effect, circuit life, filter efficacy, and complications 4.

Bleeding Complications

• Bleeding complications are a significant risk in patients receiving anticoagulation therapy, particularly those with chronic kidney disease (CKD) 5, 6.
• A lower heparin bolus dose may result in lower activated partial thromboplastin times (aPTT) and less bleeding complications in patients with CKD undergoing primary percutaneous coronary intervention (PPCI) 5.
• Patients with activated partial thromboplastin times (aPTT) >80 s are at increased risk of bleeding complications 6.