Solitaire AB stent mechanical embolization combined with catheter contact thrombolysis for acute renal artery embolism: A case report

Abstract

Acute renal artery embolization is a rare disease resulting in interruption of blood flow, resulting in renal tissue ischemia or necrosis, and even developing into acute renal failure. It is urgent to diagnose timely, recanalize the occluded renal artery early, and recover renal blood perfusion. Here, the article reports a case of acute renal artery embolization, which was successfully cured by interventional therapy.

1. INTRODUCTION

Acute renal artery embolization is a rare disease in which the emboli in the blood appeared in the main renal artery and/or its branches, leading to thrombus formation or lumen blocked. Such physiological changes could result in interruption of blood flow, renal tissue ischemia or necrosis and even develop into acute renal failure. It has an acute onset, without specific clinical symptoms and signs, and is easily confused with the acute abdomen. However, there are symptoms – acute abdominal pain, usually on the side of the infarct, or flank pain. Therefore, it is urgent to diagnose timely, recanalize the occluded renal artery early, and recover renal blood perfusion. With the rapid development of imaging equipment and interventional technology, endovascular therapy has gradually become the main treatment for acute renal artery embolism. At present, endovascular therapy mainly includes catheter‐directed thrombolysis, thrombus aspiration, stent thrombectomy, and percutaneous transluminal angioplasty. Here, the authors reported a case of mechanical thrombectomy with Solitaire AB stent combined with catheter‐directed thrombolysis in the treatment of acute renal artery embolism in Nanchong Central Hospital, in order to deepen the understanding and attention of the disease.

2. CASE REPORT

An 85‐year‐old woman with a history of coronary heart disease and atrial fibrillation for many years presented to a local hospital with abdominal pain and fever for 1 day, she was admitted to the local hospital with “acute appendicitis”. A contrast‐enhanced CT was performed and it found that the right renal artery was occluded (Figure 1). Thus, acute renal artery embolism was diagnosed, and the elder woman was rapidly transferred to the authors' hospital in order to carry on emergency interventional therapy. The arteriography was performed under local anaesthesia via the right femoral artery with a five French sheath. First, a 5F pigtail catheter was placed for abdominal aortography, which revealed filling defects in the main trunk and branches of the right renal artery, and the opening of the right renal artery was clubbed. Then a 5F Cobra catheter was inserted into the opening of the right renal artery and angiography was performed again to further clarify the location and scope of renal artery embolism and to find out the compensation of renal artery collateral vessels. Next, a 6F guiding catheter was inserted into the proximal end of the occluded vessel, so as to provide strong support for the subsequent thrombectomy with the Solitaire AB stent and facilitate thrombus aspiration. A 2.7F microcatheter was super‐selectively inserted into the distal end of the embolus through the occluded segment of the thrombus under the guidance of a 0.014 guide wire. A Solitaire AB stent (EV3 Company, USA) was inserted through the microcatheter. The length of the stent was suitable to completely cover the occluded segment of the blood vessel. After releasing the stent completely, it was left in place for 5 min, and then the embolus was removed together with the microcatheter by gently and slowly pulling it back into the guiding catheter and out of the body. After thrombectomy, angiography showed that the right renal artery trunk and some branch arteries were visualized again, but some branch arteries still had filling defects (Figure 2). The guiding catheter was withdrawn, and the 5F Cobra catheter was reinserted to indwell for catheter‐contact thrombolysis. Urokinase was pumped through the 5F Cobra catheter (600 000 units/day) for 3 days. 3 days later renal arteriography was performed again, which found that the right renal artery trunk and branch arteries were well visualized without obvious filling defects (Figure 3). A renal contrast‐enhanced CT was performed 4 days later and showed that the perfusion of the right kidney was restored (Figure 4). During hospitalization and follow‐up, we successively tested the renal function of the patient and found no obvious renal function damage (Table 1). The patient did not suffer any complications and was discharged on the 6th day after intervention.

FIGURE 1.

Contrast enhance CT: (A) Axial view showing occlusion of the main trunk of the right renal artery, indicated by the arrow. (B) Coronal view showing inadequate perfusion of the right kidney.

FIGURE 2.

Interventional procedure: (A) Abdominal aortogram shows occlusion of the right renal artery, and the main trunk of the right renal artery is pestle‐shaped, the arrow shows the right renal artery. (B and C) The interventional process of Solitaire AB stent mechanical removal of the right renal artery thrombotic, the arrow shows the Solitaire AB stent. (D) Thrombus removed during operation. (E) The angiographic found that the right renal artery immediately after thrombectomy revealed that the main trunk of the right renal artery was recanalized.

FIGURE 3.

Comparison of renal arteriograms before and after the main right renal artery has been opened: (A) Right renal artery angiography after embolization. (B) Right renal artery angiography 3 days after placement of thrombolytic therapy.

FIGURE 4.

Renal contrast‐enhanced CT examination 4 days later: (A) Axial position showing right renal artery trunk recanalization. (B) MIP reconstruction showing right renal artery. The arrow shows the right renal artery.

TABLE 1.

Comparative analysis of renal function indexes

	First presentation	Pre‐op	First day post‐op	Third day post‐op	Fifth day post‐op	A month post‐op
Uric acid (208–428 μmol/L)	298	283	287.1	298	402	300.6
Creatinine (57–110 μmol/L)	98	81	96	101	71	67
Urea (3.1–9.5 mmol/L)	5.91	6.13	5.6	8.97	4.25	4.42
LDH (135–240 U/L)	449	487	421	237	201	198

3. DISCUSSION

The kidney is a rare organ involved in arterial thrombosis compared with the lungs and brain, and it is rare and its clinical symptoms are not specific. Based on this phenomenon, more attentions need to pay to the disease due to the urgency and adverse consequences of acute renal artery embolism by clinicians. When acute abdominal pain of unknown origin is found in clinical work, the existence of this rare disease should be considered. If not diagnosed and treated in time, it will often cause irreversible renal damage, even renal failure. Renal artery embolism is caused by the dislodgement of emboli from other parts of the body, of which cardiac emboli account for the majority. Some studies have reported that about 70%–94% of renal artery embolism is caused by the dislodgement of cardiac emboli. ¹ , ² In this case, the patient had a previous history of atrial fibrillation for many years and was considered to have a cardiogenic embolus dislodged causing a renal artery embolism. The clinical symptoms of acute renal artery embolism often show acute abdominal pain, fever, nausea, vomiting, etc., and a few can be manifested as hematuria, proteinuria, renal insufficiency, and so forth. ³ , ⁴ In this case, the patient who presented with abdominal pain and fever in the early stage was misdiagnosed with appendicitis by the local hospital. The diagnosis of acute renal artery embolism mainly depends on imaging examination, in which B‐ultrasound can observe the slowing of blood flow in the main trunk or branch of the renal artery, but it has limited ability to assess the perfusion of the kidney. ⁵ CT and MRI are powerful evidence for the diagnosis of renal artery embolism, which can not only clarify the blood flow changes of the main trunk and branches of the renal artery, but also observe the volume, density, or signal changes of the kidney, and assess the site and degree of renal ischemia. ⁶ , ⁷ In this case, the right renal artery embolism was diagnosed timely by a contrast‐enhanced CT. Renal arteriography is the gold standard for the diagnosis of renal artery embolism because it can show changes in blood flow in the renal artery and branch vessels, and can clearly demonstrate intraluminal filling defects. ⁸ However, it is an invasive test that is generally used in clinical practice for preoperative renal artery flow assessment in patients who are undergoing thrombolytic therapy and for renal arteriography review to assess the efficacy of thrombolytic therapy during thrombolysis.

The treatment of acute renal artery embolism was previously based on pharmacological anticoagulation, thrombolytic therapy, and surgical treatment, but the efficacy of anticoagulation and thrombolytic therapy on cardiogenic emboli and main stem occlusion of the renal artery is limited. ⁹ , ¹⁰ With the advancement of devices and interventional techniques, endovascular treatment is gradually becoming the main treatment modality for this disease. The current endovascular treatment of renal artery embolism includes catheter contact thrombolysis, thrombus aspiration, stenting, and percutaneous transluminal angioplasty. ¹¹ , ¹² , ¹³ Catheter‐contact thrombolysis and thrombus aspiration have the disadvantage of not opening the renal artery trunk and restoring renal artery blood flow in a timely manner. Thrombi in small branches of the renal artery cannot be removed completely was the main disadvantage of Stent thrombectomy, represented by Solitaire AB stent thrombectomy. Therefore, a combination of multiple modalities can often play an important role in the treatment of renal artery embolism. Endovascular mechanical thrombectomy combined with catheter contact thrombolysis is currently recommended as a more common choice for the treatment of renal artery main stem embolism. In this case, the main renal artery was embolized and implicated the branches of the right renal artery. We adopted the treatment of Solitaire AB stent thrombectomy combined with catheter contact thrombolysis. Firstly, Solitaire AB stent was used to remove the embolus, and the main renal artery was opened as soon as possible to restore blood flow. Then we used a micro pump to pump urokinase through the catheter to target the embolus of the branch artery for local thrombolysis, and finally achieved the purpose of restoring the blood supply of the branch artery and restoring the function of the kidney as much as possible. A number of studies have confirmed the safety and efficacy of Solitaire AB stent thrombectomy in the treatment of acute renal artery embolism. ¹⁴ , ¹⁵ , ¹⁶ The use of Solitaire AB stent thrombectomy in the treatment of acute renal artery embolism has the following advantages: (1) It can quickly dredge the blood vessels, restore the blood perfusion of the blocked renal artery, and greatly shorten the time of renal tissue ischemia, and avoid ischemic necrosis of renal tissue. (2) Its delivery system can penetrate deep into the distal renal artery, and the treatment range is significantly larger than that of the common suction catheter, especially can remove the emboli detached from the distal peripheral artery during the process of catheter thrombectomy. (3) It can be repeatedly released and recycled many times, which can greatly improve the efficiency of thrombus removal and reduce the cost of treatment. (4) Compared with a fluid dynamic aspiration device or catheter aspiration device, thrombectomy can significantly reduce blood loss. (5) For dissection or inherent severe stenosis that seriously affects blood flow after thrombectomy, stents can be released at the lesion to prevent vascular re‐occlusion and promote the establishment of collateral circulation. However, it also has some potential risks, such as vascular intimal injury of the renal artery, ectopic embolism, bleeding due to thrombolysis, and so on. Fortunately, the woman did not suffer from any complications.

There is no consensus on the therapeutic time window of renal artery embolization in various centers at home and abroad. Although, the textbook tells us that the renal ischemic tolerance time is generally 60–90 min, and the earlier the renal artery is recanalized, the better the recovery of renal function. The current study suggests that revascularization of the renal artery is also recommended regardless of the time window limitation. Studies have shown that renal perfusion can be restored by opening the renal artery after 4–40 h of renal artery occlusion. ⁷ Some studies have speculated that the vascular opening within 72 h can be referred to the treatment plan for acute stroke. ¹⁶ In Koivuviita's study, it was found that some patients could still fully recover their renal function after renal ischemia for up to 2 weeks. ¹⁷ This may be due to the formation of collateral circulation from the adrenal artery, lumbar artery, and ureteral artery, which improves the kidney's tolerance to ischemia. According to the timeline of this patient's diagnosis and treatment, it was more than 48 h since the onset of illness for this woman to undergo therapeutic intervention at our hospital (Figure 5). In the case after individualized endovascular treatment according to the patient's condition, the blood supply and renal function of the patient were well restored. Based on the literature reports and the experience of this case, we believe that early diagnosis and individualized endovascular treatment can restore the blood supply of the kidney and save the renal function of patients with acute renal artery embolism within a certain period of time (within 72 h) after onset. We recommend that if the patient's renal blood supply has other collateral circulations and more than 72 h of acute renal artery embolism, we still should actively try to open the renal artery, but this should be judged according to the actual situation of the patient.

FIGURE 5.

Timeline

Qiu S, Li C, Li C, et al. Solitaire AB stent mechanical embolization combined with catheter contact thrombolysis for acute renal artery embolism: A case report. Nephrology. 2023;28(2):130‐135. doi: 10.1111/nep.14135