The presented case requires differential diagnosis of several possible causes of the significant hemodynamic decompensation that occurred on the 11th postoperative day.
Early graft occlusion and myocardial infarction was one of the considered causes of patient’s symptoms and hemodynamic instability. Prevalence of this complication is estimated on 3-12% for venous grafts and 1–2,5% for the internal thoracic artery
. Vascular loops and tourniquets passed under the coronary arteries may damage arterial walls and intraluminal shunts may cause lesions of the vascular endothelium. Although pericardial effusion is a common finding after cardiac surgeries, but the prevalence of a cardiac tamponade does not exceed 2% and is less frequent after myocardial revascularization
. The effusion or hematoma is usually not massive and is more likely regional than circumferential. That is why the role of fluid accumulated in pericardium that should be considered as a cause of severe clinical condition and cardiac tamponade is neglected. The final clinical outcome depends on the appropriate time of rethoracotomy
Dressler’s syndrome was considered but during rethoracotomy not a bloody effusion but hematoma and fresh blood filling the pericardial sac were found. It seemed apparent that bleeding was a cause of the cardiac tamponade.
Unfortunately TTE, that should be the first step of diagnostic process in this particular case and might have disclosed pericardial effusion was not performed on admission in the local hospital. At that time, mild elevation of troponin T level was not diagnostic for an acute coronary event, as blood levels of this marker may remain increased up to 2 weeks after surgical myocardial revascularization. Cardiac tamponade was another possible cause of the elevation of troponin level. In our opinion stenting of the circumflex artery was not appropriate as the marginal venous bypass graft was well functioning. Introduction of double antiplatelet therapy might have increased the oozing bleeding and caused further patient’s destabilization.
Another possible complication after beating heart surgery is an intraoperative mechanical heart wall damage with suction devices. Mandke et al.
 presented a case of subepicardial hematoma, which was evacuated intraoperatively, but early after the surgery dissecting intramural hematoma with tamponade occurred.
OPCAB procedure may lead to an acute ascending aorta dissection as a result of the partial clamping of the aorta for suturing the proximal anastomoses. Hagl and Griepp
 suggested that in case of poor aortic wall quality the risk of dissection is even higher for OPCAB than procedures under ECC. Some authors emphasized underestimation of this complication, which prevalence is 3-5%, especially in cases of sudden postoperative deaths with ventricular tachyarrhythmias
. Iatrogenic ascending aorta dissection can occur at any time after the operation. It often presents as acute neurological deficits, rapidly arising mediastinal hematoma and finally aortic rupture. Such cases must be aggressively treated. However iatrogenic dissection can be clinically silent and found incidentally with conservative treatment as a solution
. In our patient neither the clinical presentation nor the dynamics of arising effusion indicated dissection. The diagnosis of our experienced echocardiographist based on TEE excluded the presence of aortic dissection and was definitively confirmed during re-exploration of the mediastinum.
The most interesting issue in this case are the confusing results of imaging examinations. The firstly performed 16-slice CT, considered as diagnostic tool of relatively low sensitivity and specificity, revealed limited dissection of the ascending aorta at the area of the proximal bypass graft anastomosis, which was not confirmed on subsequent TEE. Thinking of the possible explanation of this diagnostic discrepancy we considered iatrogenic aortic dissection as a result of proximal bypass graft anastomosis or at the time of coronary artery bypass angiography, self-healed within following hours. Garg P et al.
 described spontaneous recovery of aortic dissection in several hours.
Salerno et al.
 reported a fatal case of descending aorta injury. Fukui et al.
 described a case of a lesion in the pulmonary vein with retrocardiac hematoma formation.
The presented case is an example of a rare but extremely dangerous complication of beating heart revascularization. The authors believe that a lesion of a pericardial or aortic nutritional vessel caused by Lima-stitch resulted in the life-threatening complication. Echocardiographic examination remains the first step in diagnostic process in a patient after cardiac surgery.