pulmonary embolism ( pe ) is a relatively common cardiovascular emergency , and is associated with a high mortality.1 ) in this respect , early diagnosis of pe is clinically important . because of the variable and nonspecific clinical presentations of pe , a diagnostic testing like computed tomographic pulmonary angiography ( ctpa ) is necessary to diagnose and determine the extent of disease .
however , we sometimes experience a patient with a significant discrepancy between clinical findings and ctpa results . here
, we describe a patient with pe , in whom ctpa did not suggest the therapeutic role of surgical embolectomy . notwithstanding , based on the clinical and echocardiographic judgment ,
the patient was referred to surgery , resulting in a progressive , hemodynamic improvement postoperatively .
a 42-year - old man presented to the emergency department with recently aggravated severe dyspnea . the patient had been treated for crohn 's disease .
he experienced acute pe 2 years ago and thereafter had been on warfarin , with a target inr of 2.0 to 3.0 .
the last follow - up ctpa that had been conducted 7 weeks before revealed a decreased extent of eccentric filling defects in descending braches of both pulmonary arteries , which was improved compared to the initial exam ( fig .
concomitant baseline echocardiography revealed mildly to moderately depressed right ventricular ( rv ) systolic function , mild tricuspid regurgitation ( tr ) and pulmonary hypertension with estimated systolic pulmonary arterial pressure of 62 mm hg .
his blood pressure was 81/70 mm hg , pulse 89 bpm , respiration rate 40 breaths per minute , and body temperature 36.0 with oxygen saturation of 81% on room air .
serum level of cardiac enzymes was within normal ranges , but bnp was elevated at 396 pg / ml , and d - dimer was also elevated at 1,940 ng / ml .
initial arterial blood gas analysis showed combined metabolic acidosis and respiratory alkalosis ( ph 7.237 , pco2 12.8 mm hg , hco3 9.6
mmol / l ) and pao2 of 126 mm hg with supplemental oxygen at 10 liters / min via a partial rebreathing mask . shortly after arrival at emergency department
due to high clinical suspicion of acute pe , ctpa with venous phase imaging of lower extremities was conducted .
but ctpa did not demonstrate any interval change in the extent of pre - existing chronic pe ( fig .
1b ) , and ct venography also did not demonstrate a source of pulmonary embolism .
there was no lung parenchymal lesion which could explain the patient 's acute respiratory failure . however , echocardiography revealed an increased rv size with severely depressed rv systolic function ( fig .
moderate tr was found with maximal velocity of tr jet of 3.58 m / sec , corresponding to an estimated systolic pulmonary arterial pressure of 71 mm hg with an assumption of ra pressure of 20 mm hg ( fig .
because of refractory respiratory failure unresponsive to maximum medical management , he was subsequently connected to a venovenous extracorporeal membrane oxygenation system in medical intensive care unit .
although ctpa did not support the role of surgical intervention , pulmonary embolectomy under cardiopulmonary bypass was performed on the third hospital day with a high probability of hemodynamically significant acute pe , based on clinical and echocardiographic findings . in the operating room
, both pulmonary arteries were extensively inspected , and a large amount of organized thrombi with fresh thrombi were found in right and left pulmonary arteries extending to the segmental artery levels .
his hemodynamic parameters had progressively improved over the following 2 days , with a significant reduction in systolic pulmonary artery pressure to 40 mm hg on invasive monitoring .
however , pulmonary hemorrhage and ventilator associated pneumonia developed and he finally passed away on the 43rd postoperative day .
since the first introduction of multi - detector ct , ctpa has become the method of choice for the diagnosis of suspected acute pe in everyday clinical practice.2 ) in hemodynamically unstable patients with acute pe , ctpa is strongly recommended because of its high sensitivity for detecting ' fresh ' emboli in " large " pulmonary artery branches.3 ) however , there are two points that we should keep in mind in this setting . first , the predictive value of ctpa depends on the pretest probability of pe .
stein et al.3 ) have reported that in patients with a high pretest probability of pe , as assessed by the wells score,4 ) a negative ctpa result had a low ( 60% ) negative predictive value for pe , highlighting that clinical finding should be considered a high priority over ctpa findings in therapeutic decision - making .
second , in the setting of acute thromboembolic event on top of chronic pe , ctpa can underestimate the distribution of pulmonary emboli in the pulmonary branches .
this is especially true when the emboli are linearly located along the pulmonary arterial wall or at the subsegmental artery level despite use of multi - detector ctpa.5 ) in addition , we suggest based on this case that in - situ thrombosis occurring slowly on chronic thromboemboli is difficult to detect with ctpa . as shown in fig .
3 , fresh thrombi were clearly demonstrated on operative findings , although ctpa could not suggest their presence .
in this situation , clinical presentation of the patient must be discrepant from anatomic burden of pulmonary emboli . in this particular condition , echocardiography is able to guide therapeutic decision - making because it can reflect hemodynamic status of the patient , not simple anatomical thrombi burden .
echocardiography is frequently performed in pe patients , because it permits reliable , qualitative , hemodynamic assessment of rv size , rv systolic function , and pulmonary arterial pressure.6)7 ) prognostic information can be obtained with the help of echocardiography.8)9 ) furthermore , in a critically ill patient with worsening symptoms who can not undergo ctpa without delay , bedside echocardiography contributes to early diagnosis and treatment of pe .
kucher et al.10 ) have suggested that echocardiographic signs of rv pressure overload and dysfunction in a hemodynamically unstable patient with high pretest probability of pe may justify invasive treatment for pe . in this case , worsened hemodynamic parameters on serial echocardiography helped us to apply an invasive approach for recurrent pe .
since the patient was on a venovenous extracorporeal membrane oxygenation system , intravenous thrombolysis was not considered an initial treatment option .
as described above , ctpa can underestimate the burden of pulmonary thrombi , especially those that is distributed along the pulmonary arterial wall , at the subsegmental artery level , and in - situ thrombosis on top of chronic thrombi .
therefore , we believe that the present case is important and instructive in that hemodynamic assessment with echocardiography should be conducted to more accurately guide therapeutic strategy in clinically suspected pe patients .
 we describe a 42-year - old man presenting to the emergency department with cardiogenic shock . 
 he had a prior history of acute pulmonary embolism ( pe ) , and had been on anticoagulation for 2 years . 
 although computed tomographic pulmonary angiography performed at the emergency department showed no change in the extent of pe and did not support a role of surgical treatment , pulmonary embolectomy was recommended by attending physician based on clinical and echocardiographic hemodynamic findings like unstable vital sign and markedly enlarged right ventricle with severely depressed systolic function . 
 surgery confirmed the presence of fresh thrombi . 
 after surgery , hemodynamic status was progressively improved , but the patient died due to pneumonia and pulmonary hemorrhage . 
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Case
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