Heparin

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An event is serious (based on the ICH definition) when the patient outcome is:

• * death

• * life-threatening

• * hospitalisation

• * disability

• * congenital anomaly

• * other medically important event

A male neonate [exact age not stated] exhibited lack of efficacy during treatment with heparin for spontaneous aortic thrombosis.

The neonate was born by normal vaginal delivery. There was no maternal history of any antenatal risk factors or COVID-19-like symptoms. At birth, the neonate was healthy. On day 6 of life he developed irritability and progressive blackish discolouration of the toes of his right foot. On day 10, he presented to hospital in India. On examination, he was irritable and afebrile but non-cyanotic. The right lower limb had gangrenous changes of the toes with discolouration present up to 2cm above the ankle. He was diagnosed with lower limb gangrene owing to spontaneous aortic thrombosis in the setting of a fetal inflammatory response syndrome (FIRS) post-intrauterine COVID-19 infection. He was initiated on heparin [unfractioned heparin] infusion bolus at 80 U/kg, followed by maintenance dose of 28 U/kg/hr. The dose was adjusted by monitoring activated partial thromboplastin time. No improvement was noted (lack of efficacy). Therefore, he was thrombolysed with recombinant tissue plasminogen activator (r-TPA) bolus 0.1 mg/kg, followed by maintenance dose of 0.9 mg/kg. Post-thrombolysis, heparin infusion was continued. Doppler examination showed slightly improved circulation in both lower limbs with blood flow in the right posterior tibial artery and right anterior tibial artery distally up to 2cm above the ankle joint. He was started on dexamethasone for FIRS owing to intrauterine COVID-19 infection. Due to the progression of right limb gangrene, embolectomy was undertaken on day 12 of admission. A 1cm clot was removed from the distal aorta while a small clot was removed from the right common iliac artery. Doppler showed flow in the common femoral, deep femoral and popliteal arteries bilaterally. The aorta showed no evidence of thrombus. Unfortunately, amputation of the right limb below the knee was required on day 16 of admission. Afterwards, a unspecified low molecular weight heparin and aspirin were started. Oral corticosteroids were also continued. On day 28, he was discharged on aspirin and corticosteroids. At one month follow-up, he was doing well with good healing of the wound and adequate weight gain. No amputation stump-related complications were noted.