a 73 year old man , 158 cm and weighing 52.8 kg , was scheduled for an emergency repair of a type - a aortic dissection and concomitant coronary arterial bypass grafting .
hypertension and a transient ischemic infarct ( tia ) that occurred 3 years ago were under conservative treatment .
he had undergone aortic valve replacement surgery for severe aortic stenosis 26 years earlier , and also had had percutaneous coronary stents inserted in the left circumflex artery and right coronary artery 10 years earlier for coronary stenosis . in a preoperative review of his chest computed tomography , dissection from the sinotubular junction of the ascending aorta to the aortic arch with a large intimal defect was observed .
stenotic lesions requiring concomitant coronary arterial bypass grafting were discovered at the initial coronary aorta ct scan .
although a coronary angiogram can be a risky procedure in an aortic dissection patient , his vital signs were stable and it was necessary to evaluate a more accurate range of the stenotic lesions .
50% left circumflex artery occlusion and total occlusion of the right coronary artery was confirmed with a coronary angiogram .
duplex sonography in the carotid artery showed < 50% stenosis in both internal carotid arteries .
his preoperative blood tests showed abnormally increased levels of hemoglobin ( 20.4 g / dl ) , hematocrit ( 61.8% ) , white blood cell count ( 297,000/mm ) , and platelets ( 406,000/mm )
. in his conventional coagulation test , the international normalized ratio of prothrombin time ( 1.33 ) and activated partial thromboplastin time ( 60.6 s ) were slightly prolonged , and his fibrinogen level was slightly higher than the upper end of the institutional normal range ( 384 mg / dl ) .
he had not been diagnosed with polycythemia vera previously , however , the results of his blood tests such as thrombocytosis ( > 400,000 platelets / mm ) and leukocytosis ( > 120,000/mm ) suggested that he had polycythemia vera . in the operating room , monitoring included a five - lead electrocardiogram with continuous st segment analysis , pulse oximetry , non - invasive blood pressure , arterial blood pressure with left radial arterial catheter , bispectral index , and a cerebral oximetry .
initial vital signs , checked in the operating room , were stable with a blood pressure of 130/66 mmhg and a heart rate of 85 bpm .
anesthesia was induced and maintained with a continuous infusion of propofol , remifentanil , and cisatracurium .
following endotracheal intubation , transesophageal echocardiography was performed to evaluate cardiac function and to guide the hemodynamic treatment .
a triple - lumen catheter with introducer ( advanced venous access , edward lifescience , irvine , ca , usa ) was placed in the right internal jugular vein by a sono - guided technique , and a pulmonary artery catheter ( swan - ganz catheter , edward lifescience , irvine , ca , usa ) was also inserted .
intraoperative baseline arterial blood gas analysis showed a hematocrit level of 61% and a hemoglobin level of 20.6 g / dl . to perform acute normovolemic hemodilution ( anh ) ,
1.5 units ( 650 ml ) of whole blood was drawn and replaced with 650 ml of 6% hydroxyethylstarch solution ( he s , volulyte , fresenius kabi , deutchland gmbh , friedberg , germany ) for 30 minutes . during the procedure ,
his hemodynamic condition was stable , and following the procedure , the hematocrit level was 50% .
we also performed rotational thromboelastometry ( rotem , pentapharm gmbh , munich , germany ) analysis , and the results were within the near - normal ranges with the exception of a hypercoagulable state in some results ( table 1 ) .
the patient underwent a bentall operation , hemi - arch replacement , and coronary artery bypass grafting under cardiopulmonary bypass . during the hemi - arch replacement ,
there was deep hypothermic circulatory arrest for 41 minutes and during that period , icepacks were applied around the patient 's head , 500 mg of intravenous pentothal sodium was injected , and cerebral oximetry values were monitored continuously ( fig .
1 ) . while attempting to wean from the cardiopulmonary bypass , his hematocrit level was 43% ( hemoglobin 14.5 g / dl ) and in the rotem analysis , the results of extem showed normal values .
the results of fibtem showed a slightly higher amplitude 20 minutes after the start of assay ( a20 ) , and maximal clot formation ( mcf ) in the upper normal range indicating a hypercoagulable state . at the end of surgical
wound closure following protamine reversal , surgeons complained that there was a lot of microvascular bleeding , inconsistent with our rotem analysis .
even though the hematocrit was 29% and our transfusion guideline was not satisfied , two units of packed rbcs , 10 units of cryoprecipitate , 10 units of platelets , and two units of fresh frozen plasma were transfused .
the rotem analysis at the end of the surgery were within normal ranges . during the whole operation period ,
the values of cerebral oximetry on both hemispheres were shown to be above 60% , and for fluid management during the operation , we used crystalloid , with the exception of 650 ml colloid for anh . following transfer to the intensive care unit , his mental recovery was delayed until postoperative day 1 , and the postoperative brain mri showed an acute ischemic embolic infarct in the right basal ganglia . after starting heparinization , his neurological problems resolved fully , he was discharged from the hospital on postoperative day 13 with no neurological sequelae and without any postoperative bleeding problems .
polycythemia vera is a chronic myeloproliferative disorder characterized by excessive red blood cell production , and is more common in men , with a prevalence of 4 - 16/million . in patients with polycythemia vera ,
increased circulating red blood cells are associated with hyperviscosity of the blood , which can lead to an increased risk of thrombotic complications such as cerebrovascular accidents , myocardial infarction , or peripheral vascular events .
moreover , approximately half of the patients with polycythemia vera also have proliferation of all blood cell lines , causing thrombocytosis and leukocytosis . in a previous survey relating to postoperative outcomes in patients with polycythemia vera , an increased risk of both vascular occlusive ( 7.7% ) and hemorrhagic ( 7.3% ) complications
abnormal platelet function such as decreased platelet factor 3 , reduced platelet adhesiveness , and abnormal platelet aggregation , may in fact be associated with a paradoxical bleeding risk . in order to be positively diagnosed with polycythemia vera ,
two major criteria and one minor criterion or the first major criterion together with two minor criteria are required .
major criteria include 1 ) hemoglobin > 18.5 g / dl in men , > 16.5 g / dl in women , 2 ) presence of the jak2 v617f or similar mutation .
minor criteria include 1 ) bone marrow biopsy showing myeloproliferation , 2 ) serum erythropoietin level below the normal range , and 3 ) endogenous erythroid colony formation in vitro .
with polycythemia vera having bleeding tendency , it is necessary to distinguish this condition from secondary polycythemia .
it seems likely that this patient suffered from secondary polycythemia , because he had chronic hypoxia . in our case ,
primary polycythemia vera was suggested from the patient 's preoperative hemoglobin and hematocrit levels of 20.4 g / dl and 61.8% , respectively , and from the results of his blood tests such as thrombocytosis ( > 400,000 platelets / mm ) , leukocytosis ( > 120,000/mm ) , positive jak gene mutation , and a low level of serum erythropoietin . several perioperative pretreatments can be considered to prevent perioperative thromboembolic complications in patients with polycythemia vera , such as the use of low - dose heparin , a course of weekly phlebotomy to reduce hematocrit to below 45% , or intraoperative acute normovolemic hemodilution , extracting blood that is simultaneously replaced by colloids until the hb is reduced to 14.5 g / dl with a hematocrit level of 45% . in this case , as the patient had an emergency operation , anh was the only available technique .
our target hematocrit level after anh ( 50% ) was slightly higher than recommended , due to the patient having concomitant ischemic heart disease and several risk factors for post - procedural bleeding , such as the use of a large dose of heparin for the cardiopulmonary bypass , re - sternotomy , and deep hypothermic circulatory arrest that is usually associated with decreased coagulation factor activation , platelet dysfunction , and excessive fibrinolysis resulting in a bleeding diathesis .
anh extracted volume ( 650 ml ) was calculated as followed v = ebv  ( ho - hf ) / hav , initial hematocrit ( ho , this patient ; 60% ) , minimum allowable hematocrit ( hf , this patient ; 50% ) , average hematocrit ( hav , this patient ; 55% ) , estimated blood volume ( ebv , this patient ; 50 kg  70 ml / kg ) , volume ( v ) .
there have been a few reports of intraoperative anh in polycythemic patients undergoing cardiovascular surgery with or without cardiopulmonary bypass .
reported a case of off - pump coronary artery bypass grafting in a polycythemic patient having preoperative hemoglobin of 20.1 g / dl and hematocrit of 60.3% .
they performed anh through the venous sheath ( 650 ml of 6% he s colloid was used as replacement fluid after 2 units of blood ) and hemoglobin was reduced to 16 g / dl .
reported a polycythemic patient with preoperative hematocrit of 51% undergoing aortic dissection repair , and intraoperative anh was performed to reduce the hematocrit level to 44% .
although anh should be applied with caution in patients with ischemic heart disease , some previous studies reported its protective effects in patients undergoing coronary arterial bypass grafting .
licker et al .   demonstrated that anh has cardio - protective effects by lowering blood viscosity in patients undergoing coronary artery bypass surgery with aortic cross clamping . lowered blood viscosity
can improve coronary arterial perfusion , cardiac output , higher oxygen extraction ratios and oxygen delivery to the underperfused myocardial area .
recently , we have been reluctant to use he s colloid in cpb , depending on the operation , due to raised concerns about the increasing bleeding risk .
however , he s colloid was used at a relatively low risk in hypercoagulable status of pv .
the thromboelastographic pattern in polycythemia vera shows minute changes in reaction time and maximal amplitude and a significant increase in the alpha angle , indicating a hypercoagulable state . in our case
, we performed rotem analysis three times during the operation , and the majority of the results were near - normal and close to baseline ( after anh ) showing a hypercoagulable state ( prolongated clotting time , clot formation time ) consistent with previous reports .
however , the patient suffered from microvascular bleeding of the surgical field after weaning from cardiopulmonary bypass , which is inconsistent with our rotem analysis .
this may suggest that although the amounts of fibrinogen and platelets are increased in a polycythemia vera patient , platelet function may have been deficient , and thus associated with paradoxical bleeding .
our limitation was the platelet function test , as the platelet count was not evaluated during the operation or postoperatively .
the actual cause of the event could not be determined , however there were several related risk factors for postoperative cerebral accidents , such as the use of cardiopulmonary bypass , deep hypothermic circulatory arrest , and the presence of polycythemia .
fortunately , the patient was discharged from the hospital with no apparent neurological sequelae , and there has been no further event during the postoperative follow - up period . in conclusion ,
thus , the results of conventional coagulation tests or rotem analysis could be used carefully with consideration of the actual clinical situation in a patient with polycythemia vera .
 polycythemia vera is a chronic progressive myeloproliferative disease characterized by increased circulating red blood cells , and the hyperviscosity of the blood can lead to an increased risk of arterial thrombosis . in a previous survey regarding postoperative outcomes in polycythemia vera patients , an increased risk of both vascular occlusive and hemorrhagic complications have been reported . 
 aortic surgery involving cardiopulmonary bypass may be associated with the development of a coagulopathy , and as a result , the occurrence of thrombotic complications should be avoided after coronary anastomosis . 
 thus , optimizing the hemostatic balance is an important concern for anesthesiologists . 
 however , only a few cases of anesthetic management in polycythemia vera patients undergoing concomitant aorta and coronary arterial bypass surgery have ever been reported . 
 here , we experience a polycythemia vera patient who underwent an emergency repair of a type - a aortic dissection and concomitant coronary artery bypass grafting , and report this case with a review of the relevant literature . 
Case Report
Discussion