a 32-year male patient presented to the ed with severe dyspnea and agitation at 2:00 a.m. the patient was placed in orthopnea position and oxygen was administered .
blood pressure was 165/50 mmhg , heart rate was 113 bpm , body temperature was 36.5 c , 25 breaths of respiratory rate per minute and oxygen saturation with pulse oximetry was 78% with nasal cannula .
physical examination revealed rales as far as upper zones of both of lungs and at base of heart , and a diastolic grade 2/6 murmur of aortic regurgitation was heard .
medical history included hypertension treated with angiotensin receptor blocker ( arb ) and smoking habit .
electrocardiography ( ecg ) showed sinus tachycardia with t - wave inversion in leads di and vl .
the working diagnosis was pulmonary edema , and use of bronchodilator inhaler was initiated , as well as intravenous nitrates and intravenous diuretic therapy .
while taking arterial blood gas sample , patient s condition deteriorated and abdominal respiration pattern became obvious .
elective tracheal intubation of patient was performed , and patient was admitted to coronary intensive care unit ( cicu ) with pulmonary edema and possible acute valvular insufficiency .
transthoracic echocardiogram ( tte ) showed mild to moderate aortic regurgitation with 3.3 cm of sinus of valsalva .
systolic function of ventricle was normal and left ventricular ( lv ) cavity widened to 5.1 cm at end - diastolic volume .
arterial blood gas before intubation showed hypoxia with 76% arterial oxygen saturation and hypocarbia with metabolic acidosis of 7.13 ph .
contrast - enhanced computed tomography ( cect ) of thorax was used to refine the diagnosis . as a team , the cardiologist , the cardiovascular surgeon , and the radiologist checked the computed tomography ( ct ) images .
sinus of valsalva was 3.5 cm and no flap was found in ascending or descending aortas .
as lab test results showed coronary ischemia with positive troponin i levels ( 1.016 ng / dl ) , it was decided that a diagnostic coronary angiography ( cag ) would be performed . in the catheterization laboratory , intubation of right coronary artery ( rca ) and left main coronary artery ( lmca ) was difficult , and the test required 1 hour to complete .
pulmonary embolism and coronary artery disease as cause of acute dyspnea were ruled out , but the cause of dissection of aorta was still unclear because of possibility of a false negative ct scan .
transesophageal echocardiography ( tee ) was selected as the next diagnostic tool due to high pretest probability of aortic dissection .
tee showed a stanford type a dissection flap closing lmca ostia from beat to beat and compromising the aortic valve with moderate aortic regurgitation .
determining the appropriate diagnosis for acute heart failure was very challenging , but at 6.00 a.m. , surgery to correct a stanford type a dissection localized in the valve and coronary ostia was performed . upon further careful review of ct scan images ,
a very tiny flap was observed at the ostium of lmca ( figure 1 ) .
transverse cut view of contrast enhenced enhanced computed tomography shows a tiny flap at the ostium of lmca that was initially misdiagnosed .
acute aortic dissection is a life - threatening medical emergency that can quickly lead to death .
incidence is estimated to be 3 in a 1000 cases according to international registry of aortic dissection ( irad ) .
if left untreated , 33% of individuals will die within 24 hours of presentation , and 50% die in the initial 48 hours .
although diagnostic tests have improved , the condition remains undiagnosed in about half of patients because of variable symptoms and negative laboratory tests . after first admission tests of physical examination , vital signs , and electrocardiogram ( ecg )
; the most frequently performed tests to diagnose aortic dissection are ct , tee and magnetic resonance imaging ( mri ) .
a recent meta - analysis by shiga et al .   reviewed published studies of diagnosis of aortic dissection by tee , helical ct and mri showed that these tests have equal and reliable diagnostic value .
tee had 99% sensitivity and 95% specificity , helical ct had 100% sensitivity and 98% specificity , and mri had 98% sensitivity and 98% specificity [ 4 , 5 ] . in the present case , first admission physical examination and laboratory tests were supportive of aortic dissection .
after a misdiagnosis was made by the radiologist , the cardiologist , and the surgeon based on ct of chest , cag was performed to clarify coronary ischemia , which is contraindicated in aortic dissection .
correct diagnosis of aortic dissection was made with tee , and the patient was taken to surgery .
further examination of ct scan images then revealed a tiny flap at the ostium of lmca ( figure 1 ) .
aortic dissection may occur in a small part of aorta and not be seen in ct scan or laboratory test results .
if suspicion of aortic dissection is high , diagnosis can be made with tte and tee in intensive care units ( icus ) .
dyspnea is the major symptom of acute heart failure and an etiologic assessment must be made for every patient who presents with acute dyspnea . in the present case ,
aortic dissection compromised aortic valve and coronary ostium , increasing left ventricle end - diastolic pressure , which led to pulmonary edema and acute dyspnea . in episodes of acute dyspnea
though a diagnostic tool like ct scan may have 100% sensitivity and 98% specificity , it may also contribute to a misdiagnosed aortic dissection .
if high pretest probability is present and ct scan does not support the diagnosis , tee and mri may be used next to determine the correct diagnosis .
 acute dyspnea is a major complaint of patients admitted to cardiology and emergency departments ( ed ) . 
 acute dyspnea can be life - threatening , and is seen in cases of asthma , pulmonary embolism , acute heart failure and myocardial infarction . 
 the present case is that of a 32-year - old man admitted to the ed with orthopnea position and agitation . 
 physical examination , electrocardiogram ( ecg ) , transthoracic echocardiogram ( tte ) , contrast - enhanced computed tomography ( cect ) of thorax and coronary angiography ( cag ) helped to rule out chest disease pathologies such as pneuomo - thorax , pulmonary embolism and coronary artery disease , but were not enough to make an appropriate diagnosis in this case . because of high pretest probability of aortic dissection , transesophageal echocardiography ( tee ) was performed and a diagnosis of stanford type a dissection closing left main coronary artery ( lmca ) ostia from beat to beat was made 
 . 
CASE REPORT
DISCUSSION