Detrimental complications due to improper antithrombotic management in the preoperative period: report of two cases

Abstract

Antiplatelet agents, including aspirin and clopidogrel, and anticoagulants are widely used for the primary or secondary prevention of cardiovascular events, as well as for oth er therapeutic purposes. However, they tend to be interrupted before surgery to reduce the risk of bleeding in many patients. We encountered two cases of patients who experienced myocardial infarct (MI) or cerebrovascular events in the postoperative period due to improper antithrombotic management before surgery. The first patient was a 75 -year-old man scheduled to undergo open partial nephrectomy for renal cell carcinoma. He took an angiotensin receptor blocker for hypertension and had voluntarily stopped taking aspirin several months earlier. Preoperative electrocardiography (ECG) revealed T-wave inversion in leads I, aVL, V5–6, consistent with an interval change compared with previous normal ECG. Transthoracic echocardiography (TTE) and myocardial perfusion scan showed left ventricular ejection fraction (LVEF) of 53% and regional wall motion abnormalities (RWMAs) in left anterior descending (LAD) and left circumflex (LCX) territories; these RWMAs had not been observed on TTE taken 3 years earlier. Cardiac intervention was recommended before surgery, but the patient strongly refused this recommendation from private reason. Because he did not present with symptoms of chest pain or dyspnea, surgery first planned, followed by timely postoperative administration of aspirin. After surgery was achieved successfully without any abnormal events, spontaneous respiration was recovered and the endotracheal tube was extubated. However, the patient complained of dyspnea on post-anesthetic care unit. After the patient was moved to intensive care unit receiving oxygen 4 L/min through a mask, arterial blood gas analysis values were within normal range. However, postoperative cardiac enzymes showed increased levels of cardiac troponin I (cTnI, 3.51 ng/ml) and creatine kinase MB (0.5 ng/ml). TTE showed a reduced LVEF (30%) and new RWMAs. Therefore, postoperative acute MI and dyspnea due to left ventricular dysfunction were suspected and intravenous nitrate was infused. On postoperative day (POD) 3, nitrate infusion was stopped and intravenous heparinization was initiated. After confirming a decrease in the cTnI level to 0.789 ng/ml, heparin administration was stopped on POD 8. Follow-up TTE revealed LVEF 33% and RWMAs in LAD/LCX territories without interval change. Anti-anginal drugs, including aspirin, were prescribed, and the patient was discharged without further problems on POD 13. The second patient was a 44-year-old woman presented with right lower abdominal pain to gynecologist. Abdominal computed tomography (CT) showed bilateral enlargement of the ovaries with peritoneal carcinomatosis. She had no previous underlying disease or history of surgery. However, the patient had signs of ascites, bilateral pleural effusion, and dyspnea. Preoperative ECG and TTE showed sinus tachycardia (120 beats/min) and moderate hypokinesia of enlarged right ventricle with normal LVEF, respectively. Because CT showed deep vein thrombosis (DVT) in the anterior and posterior tibial veins in both legs, pulmonary thromboembolism (PTE) in the right lower lobar artery, she received subcutaneous injection of low-molecular weight heparin (LMWH). Diagnostic exploration surgery was planned urgently because abdominal pain aggravated suddenly. However, at that time, anticoagulation had been discontinued