Increased risk of heparin induced thrombocytopenia and thrombosis in patients with essential thrombocythemia carrying the homozygous JAK2 V617F mutation

ADAMTS13, von Willebrand Factor, Platelet Microparticles, Factor VIII, and Impact of Somatic Mutations in the Pathogenesis of Splanchnic Vein Thrombosis Associated with BCR-ABL-Negative Myeloproliferative Neoplasms

BACKGROUND

Myeloproliferative neoplasms (MPNs) are often associated with splanchnic vein thrombosis (SVT). Not all the factors involved in the thrombotic tendency are currently known.

OBJECTIVES

This study aims to evaluate a possible association between ADAMTS13, von Willebrand factor (VWF), platelet microvesicles (MV), and factor VIII activity (FVIII:C) with thrombotic events in MPN patients.

MATERIALS AND METHODS

In total, 36 consecutive MPN patients with SVT were enrolled. The MPNs were diagnosed based on clinical characteristics and one or more gene mutations among JAK-2, CALR, and MPL. As controls, 50 randomly selected patients with MPN without thrombosis, 50 patients with deep vein thrombosis without MPNs, and 50 healthy blood donors were evaluated. Complete blood count, ADAMTS13, VWF, MV, and FVIII:C in plasma were measured in all the subjects.

RESULTS

The JAK-2 mutation was found in 94% of the patients with SVT, but none were triple-negative for genetic mutations (JAK2 V617F, CALR, MPL, and exon 12). Compared to the normal subjects, in all the MPN patients (with or without SVT), the levels of ADAMTS13 were found to be significantly lower (p < 0.001) and the MV concentrations were significantly higher (p < 0.001). Among the MPN patients, the VWF and FVIII:C levels were significantly higher in the patients with SVT than those without thrombosis (p = 0.007 and p = 0.04, respectively). Splenomegaly was present in 78% of MPN patients with SVT and in 30% of those without SVT (p < 0.001). The ADAMTS13/VWF ratio was reduced in all the patients, but not in the healthy blood donors (p < 0.001).

CONCLUSIONS

The significant increase in circulating MV, VWF, and FVIII:C in the MPN patients and in the patients with thrombosis supports the role of endothelium damage in promoting thrombotic events. In particular, a significant increase in VWF and FVIII:C levels was found in the MPN patients with SVT.

Surgical Complications in Myeloproliferative Neoplasm Patient with Essential Thrombocythemia: A Case Report

Introduction

Essential thrombocythemia (ET) is a myeloproliferative neoplasm (MPN) which could complicate surgical procedures due to thrombosis and spontaneous bleeding. However, currently, there is neither concrete guideline nor prerequisite for ET patients who underwent operations.

Case Report

A 48 year-old-female was admitted to the emergency unit on 21 February 2020 due to vomiting and inability to pass gas/stool. The patient previously had an operation for uterine myoma two weeks before which showed thrombocyte count of 688,000/mm³. The patient was previously diagnosed with essential thrombocythemia with positive JAK2V617 point mutation on 24 June 2019. Laboratory examination showed thrombocyte 1,134,000/mm³ and leukocyte 22,700/mm³ suggestive of neutrophilia. CT scan showed fluid collection with blood density in the abdomen and pelvis. She was then diagnosed with obstructive ileus due to abdominal abscess and intestine adhesion. Adhesiolysis by laparoscopy was performed on 29 February 2020 with thrombocyte count of 727,000/mm³. Patient was able to pass flatus and defecate three days post-surgery. However, a decrease of hemoglobin to 8.2 g/dL on 3 March 2020 with thrombocyte count of 700,000/mm³ was suggestive of internal bleeding. She was discharged three weeks post-surgery after improvement of clinical condition with thrombocyte count of 850,000/mm³. She was given hydroxyurea 1000 mg once every two days, aspirin 80 mg OD, anagrelide 1 mg OD, and amlodipine 10 mg OD.

Conclusion

Myeloproliferative disease patients with high thrombocyte count are subjected to increased risk of thrombotic complications in perioperative settings, thus perioperative management and risk assessment are important to improve quality of life and prevent complications. Surgery in MPN patients with elevated thrombocytes may be considered if the benefits outweigh the risks. More studies in this field should be conducted in-order to provide more data for a guideline or systematic review/meta-analyses.

What cardiologists should know about essential thrombocythemia and acute myocardial infarction: report of two cases and advanced heart failure therapies considerations

We present the cases of two young male patients aged 22 and 31 without prior medical history nor cardiovascular risk factors, who presented to the hospital with large anterior ST-elevation myocardial infarction (STEMI). Urgent coronary angiography revealed acute thrombotic occlusion of the proximal left anterior descending artery in both patients. Persistent thrombocytosis was noted and subsequent investigations led to the diagnosis of essential thrombocythemia (ET) with positive JAK2-V617F mutation. Myocardial infarction as a first clinical manifestation of ET is rare but must be considered in patients without cardiovascular risk factors who show persistent thrombocytosis. In young patients without risk factors, there may be great delays before the diagnosis of STEMI is made. Longer time to revascularization of extensive STEMI is associated with adverse outcomes and cardiogenic shock which can lead to advanced therapies like heart transplant and left ventricular assist device (LVAD). Considering the favorable long-term prognosis of patients with ET, advanced therapies may be a valuable option in the presence of severe left ventricular dysfunction.