Reply to Hamidian Jahromi and Bastani: Acute early transplant renal artery thrombosis; a complex etiologic diagnosis

Implication for health policy/practice/research/medical education: This article discusses renal artery thrombosis as a complication of distal renal artery stenosis in a kidney transplant recipient. This important complication should be considered in the differential diagnosis of acute kidney injury occurring immediately post-kidney transplantation. Acute early transplant renal artery thrombosis; a complex etiologic diagnosis. ABSTRACT Dear Editor We read with interest the letter by Hamidian Jahromi and Bastani (1) on our case report (2). The answers to the questions raised in their letter are provided below: 1. Our patient received anti-thymocyte globulin (ATG). There is a case report showing the possible association between OK3 induction therapy and acute transplant renal artery thrombosis (3). There are also reports that show ATG can induce thrombocytopenia, possibly through induction of platelet aggregation (4). However, the chance of local or systemic thrombosis following ATG induction is reported to be minimal (4). Moreover, there is a report that shows rabbit ATG, by induction of thrombocytopenia, can decrease the chance of graft thrombosis in pediatric renal transplant patients (5). 2. Our patient was on aspirin when she was discharged home (6 days post-operation) and at the time of presentation to the hospital with decreased urine output (7 days post-operation). 3. During the catheterization of the transplant renal artery, a complete obstruction was observed and the occluding clot was completely resolved by mechanical thrombectomy and pharmacologic thrombectomy with tissue plasminogen activator (TPA). However, after the removal of the clot, a distal stenosis was visible on follow-up angiogram which was only amenable to stenting. Moreover, fibromuscular dysplasia most commonly has the characteristic string of beads appearance on renal artery angiography (6). This characteristic appearance was not observed in our patient. 4. Heparin infusion was started for our patient following thrombectomy. Activated partial thromboplastin time was within the therapeutic range during the first 24 hours after thrombectomy. Our patient had no episode of hypotension in post-operative period or after the initial attempt at thrombectomy and stent placement. 5. 6. All the tests for detection of a possible hypercoagulable state including protein C, protein S and antithrombin III deficiency and mutations of factor V Leiden and prothrombin 20210 were done in our patient after nephrectomy when