Rapid and rational echocardiographic-assisted management of cardiogenic shock after coronary artery bypass surgery.

N THE EARLY 1980s, when transesophageal echocardiography (TEE) was first used in the operating room, its main application was the assessment of global and regional left ventricular function. 1 Since then, there have been numerous technical advances in TEE, and the number of clinical applications has markedly increased. 1 The American Society of Anesthesiologists has published practice guidelines for the use of perioperative TEE, but the role and effect of TEE outside the cardiac operating room are still poorly explored. 2 The clinical applications of TEE have been studied in many conditions and gradually applied in the critical care setting. Echocardiography has been applied perioperatively with a limited but focused purpose, to diagnose rapidly developing perioperative hemodynamic collapse. 3-5 The authors present a case of cardiogenic shock without acute changes that developed in the intensive care unit (ICU) within 2 hours after coronary artery bypass surgery. The role of TEE in emergent diagnosis is highlighted. The uniqueness of this case lies in the immediate diagnosis following integration of the TEE findings with appropriate early management, thus preventing postoperative death. The increasing role and application of TEE, not only in the operating room but also in the ICU, is highlighted. CASE REPORT A 45-year-old man was transferred to the ICU after aortocoronary bypass surgery. He had a history of diabetes mellitus and hypertension. His hemoglobin was 16 g/dL; platelets, coagulation tests, and serum creatinine concentration were within normal limits. Recent cardiac catheterization had revealed triple-vessel coronary artery disease, a right dominant coronary circulation, and an ejection fraction of 45%. Transthoracic echocardiography (TTE) had ruled out significant valve disease and septal defects, and documented left ventricular regional wall motion abnormalities, with a 45% ejection fraction. Based on preoperative ultrasound studies, the radial arteries were judged inadequate for harvest as an arterial conduit. A left internal mammary artery harvest was therefore planned. A right internal mammary artery harvest was not considered ideal in view of potential risk for postoperative sternal wound infection related to the patient’s diabetic status. The patient was admitted to the ICU, intubated, sedated, paralyzed, placed on appropriate mechanical ventilation, and given infusions of low-dose epinephrine and nitroglycerin. A 16-gauge peripheral intravenous catheter, a right radial arterial catheter, and a pulmonary arterial catheter had been introduced via his right internal jugular vein. Cardiopulmonary bypass (CPB) time was 100 minutes, with an aortic cross-clamp time of 85 minutes. Coronary grafts were the left internal mammary artery to the left anterior descending artery, and the saphenous vein to the right coronary artery (RCA). The circumflex coronary artery was not grafted, because of diffuse disease on inspection. He had not received any allogeneic transfusion or antifibrinolytic therapy. At ICU admission, vital signs were as follows: temperature 95°F; pulse rate 88 bpm (sinus rhythm); blood pressure 120/75 mmHg; and systemic arterial oxygen saturation 99%. His central venous pressure was 10 mmHg; pulmonary arterial pressure, 30/16 mmHg; and cardiac index, 2.2 L/min/m 2 . About 1 hour after admission to the ICU the patient became profoundly hypotensive. The vital signs were: temperature 96°F; pulse rate 110 bpm (sinus rhythm); blood pressure 60/35 mmHg; and systemic arterial oxygen saturation 99%. His central venous pressure was 20 mmHg; pulmonary arterial pressure 55/34 mmHg; and cardiac index 1.4 L/min/m 2 . The ECG obtained at this point showed sinus rhythm, with no signs of ischemia (Fig 1). The diagnosis of cardiogenic shock was made. The cardiac index was normalized with titrated inotropic support using epinephrine. An emergent bedside TEE was obtained to ascertain the mechanism of cardiogenic shock. The TEE findings were as follows: no features of pericardial tamponade; no new valvular disease; and a ventricular ejection fraction of 10%, with new left ventricular inferior wall akinesis. Given this scenario, with no acute evolving ECG changes, a new onset of inferior wall akinesis, and a clinical picture suggestive of cardiogenic shock, occlusion of the RCA graft was strongly suspected. The cardiac surgical team considered emergent revision of the saphenous vein graft. The patient was taken emergently to the operating room, where he was placed on CPB for revision of the graft. A clot in the saphenous vein graft that was occluding the flow in the RCA was removed. Separation from CPB required high-dose inotropic support and intra-aortic balloon counterpulsation, which was placed under intraoperative TEE guidance. The postoperative course in the ICU was uneventful. The trachea was extubated within 24 hours, and the intra-aortic balloon counterpulsation was withdrawn within 48 hours. The patient was transferred to the surgical ward after 4 days, and had an uncomplicated hospital recovery.