IJCS | Volume 32, Nº2, May/June 2019

223 Table 4 - Clinical outcomes and postoperative complications in the first year of follow-up of patients who underwent myocardial revascularization surgery at Fundação Hospital de Clínicas Gaspar Vianna between 2013 and 2014 Variable N % 95%CI Lower limit Upper limit Clinical outcome Discharge 158 88.3 82.6 92.6 Postoperative mortality 18 10.0 6.1 15.4 Mortality after discharge 3 1.7 0.4 4.8 Cause of death Septic shock 12 57.1 34.0 78.2 Cardiogenic shock 7 33.3 14.6 57.0 Acute myocardial infarction 1 4.8 0.1 23.8 Ventricular tachycardia 1 4.8 0.1 23.8 Outpatient follow-up Lost to follow-up 30 18.9 12.8 24.9 1-2 visits 39 24.5 17.8 31.2 3 or more visits 90 56.6 48.9 64.3 Complications after discharge Recurrent angina 13 10.1 5.5 16.6 Stroke/TIA 2 1.5 0.2 5.5 Need for new MRS 1 0.8 0.1 4.2 TIA: transient ischemic attack; MRS: myocardial revascularization surgery. Lobato et al. Patients undergoing cagb in Pará, Brazil Int J Cardiovasc Sci. 2019;32(3)217-226 Original Article 2008 to 2011 showed that acute kidney failure, blood transfusion and sepsis in the postoperative period, as well as urgency/emergency procedures were associated with higher mortality. These findings were different from ours, since emergency surgery had no significant effect on mortality. 19,25 An important findingwas the lack of acutemyocardial infarction in the perioperative period in our study group, which differs from studies in the literature that report an incidence ranging from 2 to 30%, depending on the criteria used by the authors. 26 In a study on 116 patients, 24.1% had perioperative acute myocardial infarction, which was related with worse ventricular function and death. 26 This can be explained by the fact that acute myocardial infarction may be difficult to be detected in the perioperative period due to its particular characteristics during this phase, different from usual manifestation. For example, patients are usually under sedation and anesthesia and thereby not able to identify pain, requiring a high degree of suspicion by the clinician and complementary tests such as markers of myocardial necrosis, ECG and echocardiography for the diagnosis. Besides, endarterectomy, an important risk factor for perioperative acute myocardial infarction, is rarely performed in our center. The most frequent causes of mortality were septic shock, followed by cardiogenic shock, acute myocardial infarction (at clinical follow-up, after discharge) and arrhythmia. A study conducted at Instituto Nacional de Cardiologia (National Institute of Cardiology) between 2004 and 2009 showed that main causes of mortality after MRS were cardiac-related (38.7%), infection (14.1%), multiple organ failure (3.8%), neurological (1.9%) and others (41.5%). 27