Based on the available literature [4,5,6], the incidence of PMI is 0.6 to 5% depending on the target population, study design, and the PMI definition. PMI itself is not a rare complication; however, intraoperative MI complicated by refractory CS during non-cardiac surgery, as in this case, is rare. MI that develops during hepatectomy has a high risk of treatment-related bleeding, which complicates the management.
Proper preoperative assessment of cardiovascular risk is important for the prevention of PMI [1, 2]. The guidelines on perioperative cardiovascular evaluation and management published by the American College of Cardiology/American Heart Association (ACC/AHA)  and European Society of Cardiology/European Society of Anaesthesiology  have proposed a stepwise approach to perioperative cardiac assessment, including the type of surgery, comorbidities, cardiac conditions, and functional capacity. In this case, although hepatectomy was a high-risk surgery, the patient had no other risk factors as defined by the Revised Cardiac Risk Index. Furthermore, he was able to ski asymptomatically, which was equivalent to 7.5 metabolic equivalents . Therefore, following the guidelines, we proceeded with the planned surgery without further cardiovascular testing. Preoperative evaluation according to these guidelines could not reveal the risk of cardiovascular complications in this case.
Although the etiology of PMI is incompletely understood, coronary thrombosis (classified as type 1 PMI) and supply-demand mismatch (classified as type 2 PMI)  appear to be important causes. In this case, mild hypotension and slow upsloping ST depression occurred after the start of the liver resection, which persisted for approximately 30 min, after which the patient developed refractory CS. This clinical course led us to speculate that the etiology of MI in this case was a supply-demand mismatch caused by hypotension. Therefore, we administered noradrenaline and adrenaline to raise coronary perfusion pressure instead of administering a coronary dilator. We did not administer nitrates in this case, as the guidelines [8, 9] recommend avoidance of nitrates in patients with hypotension. In fact, IVUS revealed the presence of a stenotic lesion with ulceration, which strongly suggested type 1 PMI. Intraoperative factors such as inflammation, hypercoagulability, and blood pressure fluctuations might have caused plaque rupture and acute subtotal occlusion. Moreover, persistent hypotension further exacerbated myocardial ischemia, which caused left ventricular asynergy followed by functional MR, resulting in a vicious cycle of profound hypotension and coronary ischemia, leading to refractory CS.
Many recent reviews and guidelines on PMI focus on its prevention [1,2,3], but there are a few studies on the management of PMI, especially intraoperative MI. Once intraoperative MI has occurred, the management must be decided in consideration with factors such as surgical procedure, surgical progress, bleeding risk, the severity of MI, and hemodynamics. Early diagnosis and multidisciplinary approaches are important for managing this difficult clinical situation. We immediately performed TEE to investigate the etiology of CS and decided to insert IABP and perform CAG because conservative treatment could not improve the situation. Although routine use of IABP in patients with acute MI (AMI) complicated by CS is not recommended , in this case, immediate IABP insertion improved hemodynamics by coronary artery perfusion improvement and left ventricle afterload reduction. This hemodynamic improvement by IABP enabled the patient to be safely transferred to the hybrid operating room.
In general, invasive treatment for PMI has a risk of bleeding; conservative treatment is, therefore, preferred [3, 11]. In fact, Smithowitz et al. reported that only 23.6% of perioperative AMI patients were treated invasively, even among patients with STEMI . However, this patient developed refractory CS, and it seems that the patient could not have been saved without invasive treatment. Despite the extremely high risk of bleeding from the hemi-resected liver parenchyma, this case was successfully treated with invasive treatment with proper transfusion management. Many studies [12,13,14] have revealed that early revascularization reduces mortality in patients with CS complicating AMI. As with AMI, early revascularization seems to be important for patients with intraoperative MI complicated by CS, even if the bleeding risk is high.
In summary, we described a case of MI with CS during hepatectomy. Anesthesiologists should recognize that intraoperative MI can occur, even for cases evaluated as “reasonable to proceed with planned surgery without further cardiovascular testing” by the relevant guidelines. Once intraoperative MI has occurred, early diagnosis and multidisciplinary approaches are important. Despite the extremely high risk of bleeding during liver resection, the patient was successfully treated with invasive treatment and proper transfusion management.