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Correspondence: Tariq Marroush, MD, Department of Internal Medicine Residency Program, St. John Hospital and Medical Center, 19251 Mack Ave Suite 335, Grosse Pointe Woods, MI 48236
Myocardial infarction (MI) following blunt chest trauma is rare, but potentially fatal. We treated a young patient for acute MI after falling chest-first on ice while playing hockey. Coronary artery bypass grafting (CABG) was performed after percutaneous stenting attempts were unsuccessful. By reviewing the related literature, we found 179 cases, the majority of which affected young males following road accidents. Left anterior descending artery was most frequently affected followed by right coronary artery particularly in their proximal thirds. Prior to the advent of emergent angioplasty for MI, conservative management was frequently pursued, whereas subsequently both stenting and CABG were performed as initial therapy. Several cases required CABG after the failure of stenting attempts. Trauma-associated MI is uncommon but should be suspected to be properly diagnosed and managed; the potential need for CABG requires that a cardiac surgeon be informed at the time of angiography to avoid possible delay in revascularization.
Murphy SL, Xu J, Kochanek KD. Deaths: Preliminary Data for 2010. National vital statistics reports: from the Centers for Disease Control and Prevention, National Center for Health Statistics, National Vital Statistics System, 2012;60(4):1–52.
Relationship of symptom-onset-to-balloon time and door-to-balloon time with mortality in patients undergoing angioplasty for acute myocardial infarction.
Relationship of symptom-onset-to-balloon time and door-to-balloon time with mortality in patients undergoing angioplasty for acute myocardial infarction.
in 1764. They are common and vary broadly in type and severity, with imaging and electrocardiographic (EKG) abnormalities being detected in more than half of BCT cases.
Previous reports have shown that this entity was found in 2% of autopsies of BCT victims, and that only 13% of the cases underwent coronary catheterization in the first 24 hours.
reviewed 77 published cases revealing that the left anterior descending artery (LAD) is the most commonly affected vessel in these injuries, and that automobile accident is the most common causative trauma. Detailed information regarding coronary injuries and the best approach to treatment is lacking.
We recently observed a case of total occlusion of the right coronary artery (RCA) in a young man after BCT, which required coronary artery bypass grafting (CABG) after percutaneous attempts to wire the thrombus did not succeed. We report this case, review the related literature and discuss the findings for possible therapeutic implications.
Case Presentation
A 44-year-old man presented with sharp substernal pain that started after falling chest first on the ice while playing hockey. The pain did not radiate and reached 8/10 in intensity. The patient thought that his pain was due to the fall itself. He stopped playing hoping that the pain would subside; however, it only worsened.
The patient had a history of hypertension controlled with lisinopril 40 mg daily and dyslipidemia medicated with fenofibrate 200 mg daily. His family history was significant for premature coronary artery disease as his brother and grandfather died of MI at the age of 42 and 50 years, respectively. He did not smoke and led an active lifestyle.
When the pain became unbearable, the patient drove to an urgent care facility where a 12-lead EKG showed ST-segment elevation in leads II, III and augmented vector foot with reciprocal changes. The patient was transferred to our hospital where his initial blood pressure was 146/66 mm Hg, heart rate was 85 beat per minute and oxygen saturation was 96% on 3 L of oxygen per nasal cannula. A repeat EKG in the hospital showed sinus rhythm with a prominent R wave in V2, and ST-segment elevation in lead III greater than lead II, suggesting an inferior MI with posterior and right ventricular involvement (Figure 1). Emergent coronary angiogram showed a hyperdominant right circulation with an obstructing clot in the mid segment of the RCA where the thrombus burden was deemed to be high (Figure 2). As the right circulation was perfusing a large proportion of the myocardium and as prior thrombectomy trials had failed, the patient underwent emergent coronary artery bypass surgery with left saphenous vein grafting to the posterior descending artery without complication. During the procedure, multiple clots were flushed out of the artery, and an intimal dissection was seen. In the coronary care unit, the 2D echocardiogram showed global hypokinesia with ejection fraction of 40% and severe right ventricular dysfunction with anterolateral akinesia. The patient had multiple episodes of paroxysmal atrial fibrillation that were treated with sotalol in addition to warfarin. The patient was stabilized and discharged on postoperative day 11.
FIGURE 1Initial electrocardiogram with findings suggestive of inferior and right myocardial infarction.
We conducted a web-based search of the literature for case reports of MI induced by BCT using PubMed and Google Scholar with keywords: MI, trauma, and BCT. We also reviewed the references cited in the retrieved articles to obtain all possible cases. For a case to be included, it had to fulfill the World Health Organization definition of MI based on symptoms, EKG findings and elevation of cardiac enzymes,
with a logical chronological course of events where the infarction evolved as a direct result of the trauma. The primary search resulted in 746 articles of which 157 PubMed-indexed articles and abstracts were included, describing 179 different cases; these were analyzed after adding our patient׳s case. The data were double-checked for accuracy before analysis; the results are presented as percentage of the available data.
Results
Most cases (89%) occurred in males (Table 1). The mean age of the patients was 35 years, with 74% being between 20 and 50 years old.
TABLE 1Clinical features.
n (%)
Sex
Male
158 (89%)
Female
21 (11%)
N/A
2
Age: mean ± SD = 35 ± 13
<20
20 (11%)
20-30
46 (26%)
30-40
52 (29%)
40-50
34 (19%)
>50
27 (15%)
N/A
1
Trauma
Car accident
76 (43%)
Sport
39 (22%)
Motorcycle
21 (12%)
Physical altercation
15 (9%)
Occupational injuries
12 (7%)
Other
13 (7%)
NA
4
Presenting symptoms
Chest pain
126 (83%)
Obtunded/intubated
16 (11%)
Dyspnea
6 (4%)
Asymptomatic
3 (2%)
Sudden death
1 (1%)
N/A
28
Associated findings
Rib/sternal fracture
23 (13%)
Angiographic findings
Left main
9 (5%)
Two vessels
10 (6%)
Left anterior descending
99 (58%)
Proximal
79 (85%)
Middle
13 (14%)
Distal
1 (1%)
N/A
6
Left circumflex
6 (4%)
Right coronary artery
24 (14%)
Proximal
15 (71%)
Middle
4 (19%)
Distal
2 (10%)
N/A
3
Normal angiography
21 (12%)
CABG grafts
2 (1%)
N/A
9
Mechanism
Dissection ± thrombosis
120 (71%)
Thrombosis/subtotal occlusion
12 (7%)
Coronary laceration
6 (3%)
Coronary aneurysm
5 (3%)
Compressive hematoma
4 (2%)
Normal angiography
21 (12%)
N/A
12
CABG, coronary artery bypass grafting, N/A: not available; SD, standard deviation.
The trauma accounting for the injury was found to be road accidents in 55% and sport-related trauma in 22%.
Chest pain was present in 83% of the patients. Further, 11% of the patients were obtunded or intubated where the diagnosis was made with EKG, cardiac enzymes elevation or inadvertently during imaging for other purposes. Echocardiography was abnormal in 96% of the cases with a variety of findings including, but not limited to, regional wall motion abnormalities, compromised systolic function and ventricular septal defect.
Angiography revealed that the most frequently involved vessels were the LAD in 58% of cases and the RCA in 14%. The proximal segments of these vessels were most commonly affected. Normal angiography was found in 12% of the cases. Coronary dissection, with or without thrombosis, was the mechanism of injury in 120 cases (71%).
Before proving the clear benefit of percutaneous angioplasty (PCI) in managing ST-elevation MI (PAMI Trial) in 1995,
Predictors of in-hospital and 6-month outcome after acute myocardial infarction in the reperfusion era: the Primary Angioplasty in Myocardial Infarction (PAMI) trial.
In cases published before the landmark PAMI trial, 52 patients (84%) received conservative treatment while 6 patients (10%) underwent CABG, of which 2 were after failure of PCI. The trend changed significantly after 1995, where 38 patients (39%) received conservative treatment and 37 patients (38%) had primary PCI. CABG was employed in 18 patients (19%), of which 6 underwent PCI. Overall, 14 patients died (8%), and we did not observe an improvement in this percentage between the 2 eras.
Of the 166 patients who survived, 67 had follow-up information with 36% developing heart failure and 64% having preserved cardiac function.
Discussion
Our findings are largely in agreement with smaller previous reports.
The distribution of age, sex and causative trauma is similar to that of BCT in general, as it was found in a series of 515 patients that the mean age was 36.9 years and the male:female ratio was 2.7:1.
Suggested mechanisms of BCT-induced MI include direct impact, deceleration forces and sudden increase in systemic resistance known as water-hammer effect.
The compliance of the sternum in younger patients may play a role in the insult by transmitting a higher proportion of the impact intrathoracically, which may also explain the preponderance of this condition to affect young individuals.
LAD was involved more frequently than RCA, although the latter is closer to the chest wall; this is explained by the vulnerable anatomic location of LAD for acceleration or deceleration forces during the traumatic event.
The relatively high percentage of normal angiographies may be due to the tendency of the coronary dissection to heal spontaneously in a similar fashion to the iatrogenic dissection related to cardiac interventions,
Coronary dissection was the most common injury in these cases, which implies that thrombolytics may cause unfavorable outcomes necessitating pursuing different reperfusion modalities when possible.
The death rate of 8% in our study may represent an underestimation, as it was previously reported at 15.5% of BCT in general.
This may be due to missing the diagnosis when death occurred early on or to the selective reporting of cases with successful outcomes.
The diagnosis of MI following BCT is challenging owing to the distracting concomitant injuries and to the absence of a specific symptom or finding. Chest pain is often attributed to the concomitant injuries and may be absent in comatose patients. On the contrary, EKG changes including ST-segment elevation,
can be detected in more than half of BCT victims even without MI. Furthermore, coronary injury is not necessarily instantaneous and can develop days after the initial insult, as seen in human
We think that it is reasonable to start evaluation of all patients with BCT by obtaining an EKG, then expanding the work-up if the EKG shows any concerning injury-like pattern or if the clinical suspicion is high.
Different modalities have been used to visualize coronary dissection, sometimes accidently, including comprehensive echocardiography with Doppler studies,
Institutional preferences and expertise should be taken into account when pursuing the diagnosis. It is also essential to obtain a screening echocardiogram in patients who present with circulatory shock following BCT; segmental motion abnormalities should prompt further assessment and evaluation.
Our findings support the sensitivity of echocardiogram, which was abnormal in most studied cases that reported these findings.
In our results, we found that a few cases, including our patient, were switched to an emergent CABG when the thrombus was difficult to wire. The explanation to this observation is unclear; the dissection may trigger a large clot burden that may impair manipulation. We also found that approximately 11% of the cases involved either the left main or 2 arteries concomitantly, which may render interventional measures more difficult, and hence it is reasonable to activate the surgical team when facing BCT-induced MI to minimize the time to reperfusion in case of inability to perform successful PCI.
Concomitant bleeding from other injuries is a major concern in treating patients with MI after BCT. Anticoagulation and antiplatelet therapy should only be initiated after significant and noncompressible bleeding has been ruled out. Frequent examinations and neurologic checks are also warranted after initiating these agents, and treatment should be considered if any symptoms related to potential bleeding develop.
Conclusions
MI in the context of BCT is a rare but devastating event. It mainly affects young patients and tends to occur in the proximal segments of both LAD and RCA with possible injuries to 2 arteries at a time in some cases. Timely diagnosis and treatment are crucial and STAT EKG should be obtained in all cases of chest trauma. Treatment should always be tailored depending on the concomitant injuries and the injury location. The urgent need for surgery remains a possibility should PCI prove inefficient or injuries seem not amenable to percutaneous measures.
References
Murphy SL, Xu J, Kochanek KD. Deaths: Preliminary Data for 2010. National vital statistics reports: from the Centers for Disease Control and Prevention, National Center for Health Statistics, National Vital Statistics System, 2012;60(4):1–52.
Relationship of symptom-onset-to-balloon time and door-to-balloon time with mortality in patients undergoing angioplasty for acute myocardial infarction.
Predictors of in-hospital and 6-month outcome after acute myocardial infarction in the reperfusion era: the Primary Angioplasty in Myocardial Infarction (PAMI) trial.
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