Pulmonary embolism (PE) is infrequent following modern ophthalmic surgery partly because postoperative immobilization is rarely required. However, following certain vitreoretinal procedures, eg, retinal reattachment and macular hole surgery, patients who have received intravitreal gas for tamponade need to position their heads in such a way that the retinal break(s) is uppermost. Head positioning is usually required for 1 to 2 weeks and may involve prolonged bed rest. Such immobilization may predispose patients to thromboembolism, especially those with other known risk factors. We report a case to highlight this risk.
A 38-year-old white woman in good general health underwent pars plana vitrectomy, endolaser retinopexy, and intravitreal sulfur hexafluoride injection under general anesthesia to treat a retinal detachment in her right eye. She was a nonsmoker and was not using oral contraceptives. She was not pregnant and had no personal or family history of thromboembolic diseases.
She rested in the prone position, facing downward, after the procedure. From the first postoperative day, she was requested to position her head for 2 weeks so that the nasal retina in the right eye was uppermost. She did this largely by lying on her right side, taking only short breaks for meals and other essential activities.
She developed pain in her calves on the fifth postoperative day. On the eighth postoperative day, she was seen with severe pleuritic chest pain on the left side and dyspnea. She did not report hemoptysis, and there was no evidence of a chest infection. She was tachypneic and in severe pain. A pleural rub was heard in the left inframammary area and left calf tenderness was demonstrable. Her electrocardiogram and chest radiograph showed no abnormalities. Perfusion-ventilation scan showed parenchymal changes in the base of the lung on the left side with perfusion and ventilation defects, and a perfusion defect in the upper lung on the right side. A diagnosis of PE was made. She was treated with intravenous heparin sodium initially, followed by oral anticoagulation with warfarin sodium for 3 months. Screening for thrombophilia disclosed activated protein C resistance caused by factor V Leiden mutation. She was heterozygous for the mutation. Her protein C, protein S, and antithrombin III levels were normal. The patient tested negative for lupus anticoagulant.
Pulmonary embolism was the leading cause of ophthalmic surgical mortality in 2 large retrospective series.1,2 Patients with retinal detachment were at significantly greater risk than other patients, with gas anesthesia at an older age and prolonged bed rest probably contributing to higher mortality.2
Activated protein C resistance caused by factor V Leiden mutation is the most common inherited predisposing cause of venous thromboembolism. The mutation is highly prevalent in the general population (5%-10%). The risk for thrombosis for subjects with the mutation is increased 5- to 10-fold in heterozygotes and 50- to 100-fold in homozygotes.3 However, several studies have shown that factor V Leiden mutation is not independently associated with fatal PE.4,5 Besides the activated protein C resistance, we believe that the prolonged immobilization secondary to head positioning contributed to the development of PE in our patient.
To our knowledge, this is the first report of PE following head positioning in a young patient with a factor V Leiden mutation. We propose that patients requiring postoperative head positioning should be carefully questioned regarding family and personal risk factors for thrombosis, eg, cigarette smoking, pregnancy, and use of oral contraceptives and, when indicated, screened for thrombophilia. Ophthalmologists should encourage all patients to perform stretching exercises or to walk for 5 to 10 minutes every hour while maintaining head positioning. In addition, for patients at increased risk, they should consider perioperative deep vein thrombosis prophylaxis with compression stockings, intermittent pneumatic compression, or pharmacological agents, or the use of silicone oil tamponade to reduce the need for head positioning.
Dr Au Eong was supported by a Tan Tock Seng Hospital Scholarship, Singapore.
Corresponding author: Kah-Guan Au Eong, MMed(Ophth), FRCS, Department of Ophthalmology, Tan Tock Seng Hospital, 11 Jalan Tan Tock Seng, Singapore 308433, Singapore (e-mail: Kah_Guan_Au_Eong@notes.ttsh.gov.sg).
Au Eong K, Beatty S, Thomas W, Sen V, Turner GS. Pulmonary Embolism Following Head Positioning for Retinal Reattachment Surgery in a Young Patient With Factor V Leiden Mutation. Arch Ophthalmol. 2000;118(9):1296-1298. doi: