What precautions should be advised for a patient with myelofibrosis undergoing splenectomy surgery to minimize perioperative complications?

Preoperative Fitness Assessment and Precautions for Myelofibrosis Patients Undergoing Splenectomy

Before clearing a myelofibrosis patient for splenectomy, you must ensure cytoreduction to maintain platelet count below 400 × 10⁹/L, initiate prophylactic anticoagulation, verify vaccination status against encapsulated bacteria, confirm good performance status, and exclude disseminated intravascular coagulation. 1, 2

Critical Preoperative Requirements

Hematologic Optimization

• Cytoreductive therapy is mandatory before surgery to prevent postoperative extreme thrombocytosis, which significantly increases thrombotic complications 1, 2
• Maintain platelet count strictly below 400 × 10⁹/L using hydroxyurea or other cytoreductive agents 1, 2
• Document baseline complete blood count with particular attention to platelet levels, as normal-to-high platelet counts (>200 × 10⁹/L) predict hemorrhagic or thrombotic complications 3
• Severe thrombocytopenia (<100 × 10⁹/L) is a marker of impending leukemic transformation and significantly worsens postoperative survival—reconsider surgical candidacy in these patients 1, 4

Infection Prophylaxis Requirements

• All patients must receive immunization against encapsulated bacteria at least 14 days before elective splenectomy 1, 5
• Required vaccines include: polyvalent pneumococcal (23-valent), meningococcal C conjugate, and Haemophilus influenzae type B 1, 5
• If discharge occurs before 14 days post-surgery, vaccinate before discharge to prevent missed immunization 1
• Arrange lifelong prophylactic antibiotics (phenoxymethylpenicillin or erythromycin if penicillin-allergic) starting immediately postoperatively 1

Thrombotic Risk Assessment

• Initiate prophylactic anticoagulation with low molecular weight heparin (LMWH) as a preoperative measure 1, 2, 5
• Myelofibrosis patients have inherently elevated thrombotic risk affecting both portal and systemic venous systems 5
• Extended prophylaxis with LMWH should continue postoperatively given the high-risk nature of splenectomy 1

Absolute Contraindications to Surgery

Clinical Exclusion Criteria

• Poor performance status—patient must have adequate functional capacity to tolerate major surgery 1
• Clinical or laboratory evidence of disseminated intravascular coagulation (DIC)—this is an absolute contraindication 1
• Active infection of any kind 5
• Blast crisis or leukemic transformation 6

Risk Stratification and Informed Consent

Expected Perioperative Outcomes

• Perioperative mortality ranges from 5-10% in myelofibrosis patients 1, 2
• Postsplenectomy complications occur in approximately 50% of patients 1, 2
• Common complications include: surgical site bleeding (14%), thrombosis (9.9-12%), infection (9.9-42%), subphrenic abscess, accelerated hepatomegaly, and extreme thrombocytosis 1, 4, 3, 7
• Leukemic transformation occurs at unexpectedly high rates postsplenectomy (42.8-44% of deaths), though causality remains unclear 3, 7

Predictors of Poor Outcome

• Age <50 years with normal-to-high platelet count and huge splenomegaly (>16 cm from costal margin) predicts hemorrhagic/thrombotic complications 3
• Preoperative thrombocytopenia (<100 × 10⁹/L) significantly decreases postsplenectomy survival 4
• Surgery performed >1 year after myelofibrosis diagnosis has significantly higher morbidity (64% vs 13%) and increased intraoperative blood loss 8

Surgical Team Requirements

• An experienced surgical team is mandatory given the complexity and high complication rates 1
• Multidisciplinary coordination with hematology, anesthesiology, and perioperative medicine teams is essential 1, 5
• Ensure availability of platelet apheresis capability for postoperative extreme thrombocytosis management 4

Postoperative Monitoring Plan

Immediate Postoperative Period

• Aggressive surveillance for arterial or venous thrombosis symptoms 1
• Monitor for extreme thrombocytosis and initiate immediate cytoreduction if platelet count rises rapidly 1, 4
• Watch for accelerated hepatomegaly, which occurs in 24% of patients, especially those splenectomized for transfusion-dependent anemia 3
• Implement mechanical prophylaxis (sequential compression devices) immediately and continue throughout hospitalization 5

Long-term Considerations

• Lifelong risk of overwhelming post-splenectomy infection (OPSI) with mortality rates approaching 50% for pneumococcal sepsis 5
• Educate patient that any fever >38°C (101°F) requires immediate emergency department evaluation 5
• Provide home supply of antibiotics for immediate use if fever develops 1, 5
• Reimmunization recommended every 5-10 years 1