Özet

Patients with myeloproliferative disorders such as primary thrombocytosis are prone to vascular thrombotic events. Splenectomy is also a risk factor for thrombocytosis. Such significant thrombosis may cause serious extremity or cardiac problems. It is beneficial to use prophylactic platelet anti-aggregating medication such as aspirin, cytoreductive agents such as hydroxyurea or anticoagulation with close monitoring in these patients that have additional risk factors. In this article, we present a case for whom medical therapy was more important and life-saving than surgery for peripheral vascular thrombosis after splenectomy operation.

The normal platelet count is 150-450 K/μL, and thrombocytosis is diagnosed when the platelet count is higher than 500 K/μL.[1] When myeloproliferative disorders occur or after a splenectomy, the platelet count can be extremely high, and when thrombocytosis is present, it can lead to a stroke, myocardial infarction, extremity ischemia, venous thrombosis, or embolic events that can be catastrophic.

Portal vein thrombosis (PVT) is a serious problem related to thrombocytosis, and Doppler ultrasonography (USG) performed before or after the splenectomy may be beneficial for detecting this condition so that treatment with prophylactic agents can begin.[2]

Myeloproliferative disorders have to be detected before splenectomies because they both can lead to serious cardiac or other thrombotic complications. Hence, it is important to monitor the platelet counts closely, and if necessary, anti-aggregating agents and anticoagulation medications can be utilized for both prophylaxis and treatment.

Surgery is also a risk factor for these patients. After arterial or venous complications, an early vascular evaluation is essential, and if an intervention is required, it should be done immediately to rescue the extremities or organs. The success of the surgery is related to the platelet count at that time, so using the proper prophylaxis and medications becomes even more critical for these patients.

A 76-year-old woman with a previous history of primary thrombocytosis had undergone a splenectomy for subscapular hematoma and rupture after a traumatic event at another hospital, and she came to our facility after the operation. On the postoperative second day, the patient began to complain of bilateral lower extremity pain, but she was taking daily doses of acetylsalicylic acid (aspirin) for the primary thrombocytosis, and there was no vascular event in her medical history. The patient’s extremities were pale, and both lower extremities were cold and cyanotic. In addition, the bilateral femoral artery pulses were palpable, but the popliteal and distal artery pulses were absent. Lower extremity arterial Doppler USG then revealed a bilateral superficial femoral artery occlusion proximal to the popliteal artery, and lower extremity arterial magnetic resonance angiography (MRA) also identified a bilateral superficial femoral artery occlusion (Figure 1). All of the laboratory tests were normal except for the platelet count (1,200 K/μL). We performed an emergency bilateral femoral embolectomy until the intraoperative popliteal pulses were palpable. Unfortunately, during the postoperative first hour, the popliteal distal pulses were lost, and the patient then underwent a popliteal artery embolectomy. However, both the popliteal and distal pulses were absent postoperatively. During her intensive care unit (ICU) stay, the patient received an intravenous systemic heparin infusion (15 U/kg/hour), but the distal perfusion could not be restored. On the postoperative second day, the patient’s liver enzymes increased [alanine transaminase (ALT): 875 units per liter (U/L) and aspartate transaminase (AST): 1256 U/L), and renal failure occurred (urea: 174 mg/dl; creatinine: 3.45 mg/dl), so a bilateral above-the-knee amputation was performed. At the 18^th hour after the amputation, the patient had abdominal tenderness, and Doppler USG detected PVT. The classic heparin treatment was replaced by low-molecular-weight heparin (LMWH), and on the postoperative 10^th d y, the patient’s liver and renal functions were restored. She was then discharged on the postoperative 14^th day.

Figure 1: Preoperative magnetic resonance angiogram image of the lower extremity arterial system showing bilateral superficial femoral artery thrombosis.

Tartışma

Trombocytosis may occur due to myeloproliferative disorders or splenectomies, and it is a well known risk factor for vascular events.[3,4] Therefore, it is essential to detect and treat it before complications occur. Prophylactic and therapeutic agents are well defined for this group of patients.[5,6] Most often, when vascular complications occur, vascular surgical or interventional procedures are inevitable, and, unfortunately, they most often have poor outcomes. This is probably caused by the deterioration of the vascular structures due to asymptomatic recurrent thrombosis. In our patient, vascular surgery was attempted, but we ultimately had to perform a bilateral leg amputation.

Portal vein thrombosis is a rare but significant complication associated with splenectomies performed for hematological diseases, with myeloproliferative diseases being the most common hematological disorder that causes this condition. These are followed by hemolytic anemia, hereditary spherocytosis, and thalassemia major and idiopathic thrombocytopenic purpurae. Prolonged unexpected febrile and abdominal tenderness in patients who have undergone a splenectomy must be promptly evaluated for the development of PVT, and Doppler USG may then be performed to diagnose this condition. Furthermore, prophylactic antiplatelet and antithrombotic therapy should be considered after splenectomies to help prevent PVT.[2]

Asplenia also has been known to predispose patients to infection, and infectious complications associated with the postsplenectomy state are well documented.[7] Thus, a discussion should be take place with the patient regarding special perioperative management. Our patient had a vascular operation and bilateral amputation. We used prophylactic antibiotherapy for all of her operations, and she did not experience any infectious complications.

The risk to the patient from the increased platelet count should be assessed first. Patients with thrombocytosis who have had thrombotic events and possess cardiovascular risk factors should be treated with hydroxyurea, interferon alpha, ticlopidine, enoxaparin, and anagrelide, a newer plateletlowering agent that has been approved for patients with essential thrombocytosis[5,6] either before or after vascular surgical procedures performed for thrombocytosis. The risk of bleeding associated with the use of aspirin should be kept in mind for patients with thrombocytosis, and patients taking hydroxyurea should be monitored for leukemic transformation. Another treatment option for rapidly reducing the platelet count in life-saving clinical situations is plasmapheresis, which involves the removal, treatment, and return of plasma from the circulating blood.

Par tial splenectomies and splenic autotransplantation techniques may also protect against complications, but whether or not they do this job as well as a total splenectomy remains controversial. Currently, prophylaxis remains the treatment of choice to prevent complications after a splenectomy.

Thrombocytosis is a serious risk factor associated with vascular and cardiac events after a splenectomy performed for myeloproliferative disorders. Therefore, either before or after surgical interventions, prophylactic medical therapy with anti-aggregating and anticoagulating agents is essential for these patients.

Declaration of conflicting interests
The authors declared no conflicts of interest with respect to the authorship and/or publication of this article.

Funding
The authors received no financial support for the research and/or authorship of this article.

Kaynaklar

1) Griesshammer M, Bangerter M, Sauer T, Wennauer R, Bergmann L, Heimpel H. Aetiology and clinical significance of thrombocytosis: analysis of 732 patients with an elevated platelet count. J Intern Med 1999;245:295-300.

2) Soyer T, Ciftci AO, Tanyel FC, Senocak ME, Büyükpamukçu N. Portal vein thrombosis after splenectomy in pediatric hematologic disease: risk factors, clinical features, and outcome. J Pediatr Surg 2006;41:1899-902.

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5) Harrison CN, Campbell PJ, Buck G, Wheatley K, East CL, Bareford D, et al. Hydroxyurea compared with anagrelide in high-risk essential thrombocythemia. N Engl J Med 2005;353:33-45.

6) Storen EC, Tefferi A. Long-term use of anagrelide in young patients with essential thrombocythemia. Blood 2001;97:863-6.

7) Dahyot-Fizelier C, Debaene B, Mimoz O. Management of infection risk in asplenic patients. Ann Fr Anesth Reanim 2013;32:251-6.