Abstract
Anteriorly displaced right coronary artery (RCA) and anomalous origin RCAs occur in ≈1% and 0.1% of adult patients, respectively, and are the leading cause of incomplete coronary angiography and prolonged procedure times. We present a case in which anteriorly displaced RCA occlusion resulted in an acute inferior–posterior–right ventricular myocardial infarction complicated by complete atrioventricular block and hypotension. Failure to image the RCA resulted in considerable delay in reperfusion time with fibrinolysis.
The authors discuss the most frequent anatomic locations of ectopic RCAs and suggest an algorithm to be employed when an ectopic RCA cannot be imaged with conventional diagnostic catheters. Contrary to popular belief, the search for an ectopic RCA has <90° boundaries limited to the anterior third of the right sinus and anterior half of the left sinus.
1
Case presentation
A 47-year-old African-American female reported sudden onset of chest pain occurring 3 h after cocaine use and 60 min prior to her hospital admission. Chest pain was associated with diaphoresis and presyncope. The patient was a cigarette smoker and occasional cocaine user and was not known to suffer from any medical problem or receive any medical therapy. The EMS transmitted EKG via LifeNet ( Fig. 1 ) which revealed acute inferior–posterior wall myocardial infarction as well as probable right ventricular infarction (ST elevation in V 1 lead). In transit to the university hospital, the patient received aspirin 325 mg and 500 ml normal saline intravenously for hypotension. In the emergency department, heparin bolus (4000 U intravenously) was given and the patient was transferred to the cardiac catheterization laboratory (CCL).
On admission, the patient appeared to be in distress and reported severe chest pain (8 of 10). Her blood pressure was 99/51, heart rate was 48 (regular), respiratory rate was 25, and pulse oxymetry was 92% on room air. Cardiac exam and lung examination results were unremarkable with the exception of jugular venous distention. The admission laboratory blood work was all within normal range. The patient was transferred to the CCL for coronary angiography (CA) and percutaneous coronary intervention. The left coronary artery was not affected by significant obstructive coronary disease ( Fig. 2 ). The right coronary artery (RCA) could not be imaged. Ventriculography and aortography ( Fig. 3 ) failed to image or disclose the location of the RCA. After numerous attempts using multiple catheter shapes and sizes, the RCA could not be visualized. During these attempts, the patient developed complete atrioventricular block and severe hypotension which required temporary transvenous pacing and dopamine administration. CT angiogram was done emergently (using a 16-slice CT while employing a dissection protocol). The CT angiogram demonstrated normal aorta and failed to disclose the orifice of the ectopic RCA. After a failed second attempt to image selectively the RCA, tissue plasminogen activator was administered (225 min from emergency department arrival) with subsequent evidence of successful reperfusion (80% ST elevation and pain resolution 90 min after fibrinolysis administration). On the day after admission, creatine phosphokinase and troponin I peaked at 8369 U/l and 227 ng/ml, respectively. Transthoracic echocardiogram showed right ventricular dilation with hypokinesis as well as akinetic inferoposterior wall. Subsequently, transesophageal echocardiogram demonstrated that the RCA was originating from the anterior one third of the right cusp ( Fig. 4 ). In addition, color flow Doppler demonstrated normal RCA flow: flow velocity during systole exceeding flow during diastole ( Fig. 5 ). The RCA course was delineated: from left superior to right inferior region. Equipped with this information, we used an Amplatz Left 4-French catheter to successfully catheterize and image the anteriorly displaced RCA ( Fig. 6 ).
2
Discussion
Ectopic RCAs are the most frequent cause of incomplete CA and prolonged procedure and fluoroscopy time during CA and PCI . Since there are no universally accepted definitions for ectopic RCAs, there are considerable variations in the reported frequency of this condition ranging between 0.04% and 0.46% . However, most reports do not include the anteriorly displaced RCA as a coronary anomaly.
2.1
Location of ectopic RCAs
Villalonga reported that former studies by Banchi and Hackensellner suggest that RCAs originate from the posterior third, middle third, and anterior third of the right sinus in 40%, 59%, and 1%, respectively ( Fig. 7 ). Since 99% of RCAs originate from the posterior two thirds of the right sinus, for the purpose of our discussion, ectopic RCAs will be defined as RCAs originating outside that zone. Pathology series reveal that high takeoff RCAs [defined as RCAs originating >10 mm superior to the sinotubular junction (STJ)] are encountered less frequently (14%) than high takeoff left coronaries (36%). High takeoff RCAs usually do not present an imaging challenge during CA since they can be imaged subselectively by a right sinus injection and selectively by conventional right diagnostic catheters (Judkins Right 3–4, Amplatz Right 1–2, or Williams curves).
