a 60-year - old woman ( height , 150 cm ; weight , 58 kg ) was scheduled for aortic and mitral valve repairs with maze procedure for mixed aortic and mitral valvular heart disease with atrial fibrillation ( af ) .
the preoperative electrocardiogram showed af with ventricular rates of 60 - 100/min and left ventricular hypertrophy .
transthoracic echocardiography ( tte ) and cardiac computed tomography ( ct ) revealed an ejection fraction of normal range and a dilated left atrium ( la ) and ventricle , as well as moderate aortic regurgitation and moderate mitral stenosis and regurgitation .
coagulation profiles were as follows : prothrombin time ( pt ) 14.9 s , international normalized ratio ( inr ) 1.14 , activated partial thromboplastin time ( aptt ) 35.2 s , and fibrinogen 255 mg / dl . upon arrival at the operation room , after establishing routine invasive arterial blood pressure and noninvasive patient monitoring ( electrocardiography , pulse oximetry , bispectral index , and cerebral oximetry ) , anesthesia was induced and maintained using target - controlled infusion of propofol ( target concentration , 1.2 - 1.3 g / ml ) and remifentanil ( target concentration , 10 - 20 ng / ml ) . muscle relaxation was achieved with the administration of a bolus of rocuronium under the guidance of peripheral monitoring of neuromuscular transmission .
then a pulmonary artery catheter ( swan - ganz ccombo cco / svo2 , edwards lifesciences , irvine , ca , usa ) was inserted after anesthesia induction .
tee probe ( 6 t probe , ge healthcare , waukesha , wi , usa ) was inserted .
tee ( vivid 7 , ge healthcare , waukesha , wi , usa ) revealed no intracardiac thrombus , as was seen in the preoperative tte and cardiac ct . the activated clotting time ( act ) before cpb was 140 s. cpb was initiated after heparin 300 units / kg was injected , and act above 450 s was achieved . during cpb for 211 min , the act was checked every 60 min and maintained above 450 s with additional heparin 2,000 units given 60 min after cpb started .
aortic and mitral valve repairs using bovine pericardium , a mitracon strip ( mitr - lift , sciencity , wonju - shi , kangwon - do , korea ) , and a sinotubular junction ring , and following the maze procedure , were successfully performed without unexpected events .
defibrillation with 50 j was applied and tee was performed to evaluate aortic and mitral valve and regional wall motion abnormality .
the core temperature reached 36 and weaning of cpb was attempted . at that time , a mobile hyper - echogenic mass in the la was detected via tee ( fig .
it had a distinct border and different echogenic density than that of blood or the atrial wall .
at that point , the act was checked and recorded at 504 s. rotation thromboelastometry ( rotem , tem innovations , munich , bayern , germany ) showed hypocoagulability , with clotting time ( ct ) of 972 sec ( normal 100 - 240 sec ) , clot formation time ( cft ) of 330 sec ( normal 30 - 110 sec ) , -angle 33.5 ( normal 70 - 83 ) , and maximum clot firmness ( mcf ) of 49.8 mm ( normal 50 - 72 mm ) .
after discussions with the cardiac surgeons , cpb was re - started for surgical confirmation and proper management of a mobile hyper - echogenic mass . left atriotomy revealed that the mass was a thrombus , 15  20 mm in size with an irregular spherical surface ( fig .
protamine was injected for neutralization of heparin and an act of 124 s was recorded .
during cpb , three units of packed red blood cells ( rbcs ) were transfused . after weaning from cpb , eight units of platelet concentrates ,
three units of fresh frozen plasma ( ffp ) , and three units of rbcs were transfused . on completion of the operation , weaning from cpb was accomplished uneventfully .
the patient was transferred to the intensive care unit ( icu ) . in the icu ,
mild coagulopathy was observed with pt 18.1 s , inr 1.46 , aptt 35.2 s , fibrinogen 189 mg / dl , d - dimer 5.40 mcg / ml , and platelets 72000/mcl .
after 3 days , the patient made an uneventful recovery and was transferred to a general ward .
intracardiac thrombus during or just after cpb have rarely been reported . in one such rare case ,
gillham and tousignant   reported severe acute thrombosis of a mechanical aortic valve prosthesis while the patient was fully heparinized on cpb .
multiple interacting prothrombotic factors , such as use of aprotinin [ 2 - 4 ] , acquired antithrombin iii deficiency , prolonged duration of cpb , post - protamine status , transfusion of blood components , disseminated intravascular coagulation , preoperative congestive heart failure , biological glue , and multiple prosthetic surfaces , may contribute to intracardiac thrombus during or just after cpb . the report by gillham and tousignant  
in addition , the patient was resistant to heparin and an antifibrinolytic drug was also administered . in our case ,
aprotinin was not administered , nor were any antifibrinolytic drugs , and the patient had no known coagulation disorders .
no blood components , except rbcs , were transfused before cpb weaning . biological glue for aortic and mitral valve repairs was not used .
therefore , the prolonged duration of cpb ( 211 min ) might have contributed to the intracardiac thrombus in this case .
congested pulmonary venous blood , related to mitral regurgitation , might become sticky during an extended cpb .
the patient had no right - to - left cardiac shunt , such as a patent foramen ovale .
therefore , the intracardiac thrombus would have originated from the left cardiac chamber itself or the pulmonary veins .
sudden development of refractory hypotension with a rapid rise in pulmonary artery pressures within 10 min after infusion of protamine and while closing the sternum might be key signs of right heart thrombus .
transesophageal echocardiography is a useful tool for the diagnosis and evaluation of intracardiac thrombus . in particular
, the evaluation of posterior structures of the heart , such as the la and left atrial appendage ( laa ) , is much easier with tee .
the sensitivity and specificity of tee for thrombus in the la have been reported as 93 - 100% and 99 - 100% [ 7 - 9 ] , respectively .
however , it is important to distinguish between intracardiac thrombus and artifacts or pitfalls during tee examination .
kim et al .   reported that folding of the right atrium appeared as a mass - like thrombus via tee .
pressman and figueredo   also reported misdiagnosis of the inverted laa as an la thrombus .
a large hypertrophic trabecula , stagnant blood , or a warfarin ridge can also be confused for an intracardiac thrombus . in our case , however , the mobile hyper - echogenic mass with a clear - cut margin was determined conclusively to be a thrombus .
the mass was separate from the adjacent la wall , so it could be distinguished from pectinate muscle , trabeculations , and inverted laa .
it could be differentiated from suture materials because it had no connection with the ring of the mitral valve annuloplasty and was less echogenic than suture materials . in conclusion ,
abrupt formation of intracardiac thrombus with full heparinization can occur . for early detection of an intracardiac thrombus and prevention of detrimental outcomes , meticulous
 intracardiac thrombus during cardiopulmonary bypass ( cpb ) with full heparinization is very rare but fatal . 
 a 60-year - old woman was scheduled for aortic and mitral valve repairs with a maze procedure for mixed aortic and mitral valvular heart disease with atrial fibrillation . 
 preoperative transthoracic echocardiography and cardiac computed tomography showed moderate aortic regurgitation and moderate mitral stenosis with regurgitation . 
 there was no intracardiac thrombus . 
 aortic and mitral valve repairs with the maze procedure were successfully performed without unexpected events . during cpb 
 weaning , a mobile hyper - echogenic mass in the left atrium was detected on transesophageal echocardiography . 
 after cardiac arrest , it was surgically removed . on completion of the operation , weaning from cpb was accomplished uneventfully . 
 the patient fully recovered and was discharged from the intensive care unit on her third postoperative day . 
Case Report
Discussion