Left Main Dissection and Pseudoaneurysm Formation After a Road Traffic Accident
We present here the case of a 46-year-old man, a smoker, who was involved in a motor vehicle accident. He was hit by a car while driving his motorcycle. The emergency medical care team found that the patient had a Glasgow Coma Scale score of 3 and quickly developed a bradyasystolic cardiac arrest. After successful advanced resuscitation, the ECG showed right bundle-branch block and anterolateral ST-segment elevation (Figure 1), so the patient was transported to the intensive care unit.
First, a body computed tomography scan and x-ray were done, demonstrating jaw, rib, femur, and tibia fractures without any points of active bleeding. The right bundle-branch block disappeared but the ST-segment elevation persisted on ECG. In addition, an urgent echocardiogram detected wall motion abnormalities with an anteroseptal akinetic area and a moderately depressed ejection fraction without pericardial effusion (Movies I and II in the online-only Data Supplement). Consequently, an emergency coronary angiogram showed a thin radiolucent line in the distal left main coronary artery (LMCA) that suggested intimal flap (dissection) with Thrombolysis in Myocardial Infarction (TIMI) grade 3 flow in the left anterior descending (LAD) artery and left circumflex artery (Figure 2A and Movie III in the online-only Data Supplement). In addition, the proximal LAD artery appeared moderately narrowed with an image of plaque rupture in the ostium. There was also severe stenosis in the obtuse marginal branch (Figure 2B and Movie IV in the online-only Data Supplement).
Because there was an image of dissection of the LMCA, the TIMI grade flow was 3, and there was high risk of bleeding in a polytraumatized patient, it was decided not to perform any coronary intervention but to give medical treatment and repeat the coronary angiogram in a few days. The patient received antiplatelet therapy with only 1 drug (ticagrelor) and fondaparinux as the anticoagulant. The peak level of the ultrasensitive troponin T was 10 636 ng/L. Afterward, the patient required a long stay in the intensive care unit for respiratory support. During that time, surgical correction was applied for the traumatic fractures.
Two weeks after his arrival at the hospital, the coronary angiogram was repeated. The intimal tear of the LMCA had disappeared, and there was a new image of an aneurysm that started at the distal LMCA and was parallel to the proximal LAD artery. Moreover, the image of stenosis of the proximal LAD had worsened (Movie V in the online-only Data Supplement). Intravascular optical coherence tomography revealed a lipid-rich plaque in the proximal LAD artery with significant stenosis (minimum area, 2.7 mm2), and there was an image of an intimal tear and a “neo” cavity without an intimal layer as a pseudoaneurysm in the distal LMCA and ostium of the LAD artery (Figure 3 and Movie VI in the online-only Data Supplement). Therefore, percutaneous coronary intervention (PCI) was performed. Drug-eluting stents were implanted in the obtuse marginal and then in the distal LMCA toward the proximal LAD artery, with good results by both angiography and optical coherence tomography (Movie VII in the online-only Data Supplement). A routine echocardiogram showed a left ventricular ejection fraction of 45% (just mildly reduced) with akinesia of the distal segments of the septum, anterior wall, and apex without aneurysm or thrombus. The patient achieved full recovery, and he was discharged without sequelae. Aspirin and ticagrelor were prescribed at discharge, as well as the routine treatment after an acute myocardial infarction (AMI).
Cardiac complications of blunt chest trauma (BCT) range from arrhythmias to valvular avulsions to myocardial contusion, rupture, and rarely AMI. The mechanisms that lead to vascular injury include intimal tear resulting from acceleration/deceleration forces or compression between the heart and the sternum.1 Previous reviews of AMI after BCT have reported the highest prevalence in men <45 years of age secondary to road traffic accidents.2 Furthermore, coronary dissections were found in most cases of the reported coronary angiogram for AMI after BCT.3 The most commonly affected coronary artery is the LAD (The probable explanation is the vulnerable anatomic position on the anterior part of the heart). Involvement of the LMCA is extremely infrequent.2 Posttraumatic coronary aneurysm is a relatively late manifestation of BCT and was found incidentally. In previously published cases, most patients were treated conservatively and had an uneventful clinical course.4
To the best of our knowledge, this is the first case reported of an LMCA dissection that subsequently develops a pseudoaneurysm in the distal part of the LMCA after a BCT. Our patient already had coronary artery disease (in the obtuse marginal and in the proximal LAD). The trauma probably predisposed to the intimal tear and posterior formation of the pseudoaneurysm.
Management of AMI is challenging in patients after BCT. Intracoronary imaging can help explore the mechanism of coronary injury and guide the most adequate treatment. PCI is the preferred approach to treat AMI after chest trauma, yet some cases treated by bypass surgery have been published. Hemorrhage from coexisting injuries is the main concern for PCI, so hemorrhage of important organs must be excluded before emergency PCI. Emergency PCI should be a good choice for patients without obvious hemorrhage in other organs. However, an early conservative treatment after delay of PCI is an optional method in patients with other organ hemorrhage.3 As illustrated by our patient’s case, conservative management at first (after confirming TIMI grade 3 flow) and delayed stenting can be a safe option for polytraumatized patients at a high risk of bleeding.
The online-only Data Supplement is available with this article at http://circ.ahajournals.org/lookup/suppl/doi:10.1161/CIRCULATIONAHA.115.014515/-/DC1.
- © 2015 American Heart Association, Inc.