Casualty Surgery: Cardiac thromboembolism complicating a gunshot wound to the heart

Surgical Rounds®, October 2007, Volume 0, Issue 0

L. D. George Angus, Director of Trauma and Vice-Chair; Eric Seitelman, Surgical Resident; Jean-Joseph Desir, Surgical Resident; Lioudmila Haimovicci, Surgical Resident; Leonard O. Barrett, Director of Cardiothoracic Surgery; Dahua Zhou, Attending Radiologist, Department of Surgery, Nassau University Medical Center, East Meadow, NY Departments

L. D. George Angus, MD, MPH

Director of Trauma and

Vice-Chair

Eric Seitelman, MD

Surgical Resident

Jean-Joseph Desir, MD

Surgical Resident

Lioudmila Haimovicci, DO

Surgical Resident

Leonard O. Barrett, MD

Director of

Cardiothoracic Surgery

Dahua Zhou, MD

Attending Radiologist

Department of Surgery

Nassau University

Medical Center

East Meadow, NY

Introduction: Cardiac injuries are relatively rare compared with other injuries, but they are being encountered with increasing frequency, especially at urban trauma centers. Although these injuries are life-threatening, they are not always obvious.

Results and discussion: This paper discusses the case of a patient who presented to the hospital after sustaining a self-inflicted thoracoabdominal gunshot wound. It also provides a review of the literature and discusses the presentation and management of penetrating cardiac injuries.

Conclusion: Cardiac injuries may occasionally have a subtle presentation, and clinicians should have a high index of suspicion for such injuries in any patient presenting with trauma to the precordial region of the chest.

Gunshot wounds to the heart can be devastating injuries. Our report details the case of a young woman who sustained a self-inflicted gunshot wound that required cardiac repair. The patient developed an intracardiac thrombus, which resulted in a pulmonary embolism. Intracardiac thrombus with systemic embolization following cardiorrhaphy for penetrating trauma is life-threatening. Surviving patients should be monitored for delayed sequelae that require further evaluation and management. We review the literature and discuss the presentation and management of penetrating cardiac injuries.

Case report

A 29-year-old woman presented to the hospital after sustaining a self-inflicted thoracoabdominal gunshot wound. Her vital signs were stable, with a heart rate of 103 beats per minute. A chest radiograph was normal. Evaluation using advanced trauma life support (ATLS) protocol revealed a through-and-through gunshot wound that entered to the left of the xyphoid cartilage and exited from the left lower back. A nasogastric tube revealed gross blood.

Ertapenem sodium was administered as a preoperative antibiotic, and the patient was taken to the operating room (OR) for an exploratory celiotomy. The abdomen was explored through a midline incision, and a through-and-through stomach injury was observed. Her stomach was filled with clots, which were evacuated, and the stomach was repaired using a linear 4.0 x 4.5-mm stapler. A bleeding laceration to the left lobe of the liver also was noted, and the bleeding was controlled using a 0-chromic blunt liver suture. No other gastrointestinal injuries were observed.

On further exploration of the tract of the injury, a small isolated clot was observed anteriorly at the junction of the left hemidiaphragm and the pericardial sac, raising a high index of suspicion for a cardiac injury. There was no evidence of cardiac tamponade, and the patient's vital signs remained stable throughout the procedure. Given the high clinical suspicion for a cardiac injury, the midline incision was converted into a thoracoabdominal incision for complete exploration of the heart and left chest. Upon opening the pericardium and removing the clot, a 1.5-cm laceration at the apex of the heart involving both ventricles was noted with active bleeding. The bleeding was controlled with digital pressure followed by an expeditious repair of the cardiac injury using 2.0 polypropylene sutures with pledgets. The pericardium was re-approximated in an interrupted fashion followed by placement of a left chest tube. The patient's vitals remained stable after her wounds were closed, and she was transported to the intensive care unit.

On postoperative day 1, the patient was recovering well and was extubated without distress. She was placed on subcutaneous heparin, 5,000 units every 8 hours, as prophylaxis for deep vein thrombosis (DVT). On the morning of postoperative day 2, she became hypoxemic, hypotensive, and bradycardic, requiring re-intubation with a fraction of inspired oxygen of 100%. Following resuscitation with fluids, a computed tomography (CT) scan was performed, which showed a significant pulmonary embolism in the intermediate branch of the right upper lobe of the lung, no evidence of DVT, and a 1.5-cm thrombus at the apex of the left ventricle (Figure). An echocardiogram showed good cardiac function and no valvular or septal abnormalities.

The patient was given 5,000 units of intravenous heparin and started on a heparin drip of 1,000 units per hour for full anticoagulation. She was stabilized and returned to the OR for a retained hemothorax and washout of her left chest. Upon the patient's discharge from the hospital 8 weeks after her injury, she was kept on therapeutic heparin, treated with the broad-spectrum antibiotics vancomycin and an imipenem-cilastatin combination, and given a regimen of 5 mg of warfarin daily. Postoperatively, she also received a short course of acetaminophen and codeine, along with antidepressants prescribed by her psychiatrist. She has since recovered from her injuries and is doing well, although she continues to battle with intermittent bouts of depression.

Discussion

Cardiac injuries are not altogether rare and are being observed with increasing frequently in urban trauma centers. Despite the sophistication of emergency medical services, 60% to 80% of penetrating cardiac injuries result in death at the scene or before arrival to a trauma facility.1,2 Patients who make it to a trauma center alive have a survival rate between 30% and 70%.3 The presentation of these cases varies considerably and can range from complete stability to cardiac tamponade leading to cardiovascular collapse and cardiac arrest.

In acute situations, cardiac penetration may go unrecognized, and a high index of suspicion is required to establish the diagnosis. In the emergency department, the presence of a cardiac injury with cardiac tamponade can be presumed in patients presenting with a precordial wound, tachycardia, pulsus paradoxus, and Beck's triad, which includes hypotension, markedly elevated systemic venous pressure, and muffled or soft heart sounds. Beck's triad has been reported to be present in only 10% to 40% of reported cardiac injury cases.4 In cases with Beck's triad, elevation of venous pressure is the most significant diagnostic finding for pericardial tamponade.5 An electrocardiogram may also exhibit low voltage in tamponade cases; however, a common clinical mistake is to expect the presence of Kussmaul's sign, which is described as jugular venous distension upon inspiration. Although this sign has been described in cases of constrictive pericarditis, congestive heart failure, or tricuspid regurgitation, it does not occur in uncomplicated cardiac tamponade cases.6 The aforementioned signs alone or in combination are neither very specific nor sensitive and are usually the exception rather than the rule; therefore, the absence of these clinical findings does not exclude a cardiac injury.

Our case exemplifies the occasional subtle and deceptive nature of cardiac wounds, which can result in complications and death should the clinician fail to suspect this injury. Our patient did not present in tamponade, nor did she exhibit any signs associated with it. All patients who sustain a penetrating injury to an area inferior to the clavicle, superior to the costal margins, and medial to the midclavicular lines should be treated as though they are harboring an injury to the heart until proven otherwise; the burden of proof lies with the trauma surgeon. On occasion, the myocardial muscle along with a blood clot can seal the injury, which prevents cardiac tamponade and maintains a patient's hemodynamic stability, allowing enough time for transport to the trauma facility and early detection of the cardiac injury.

Mortality following gunshot wounds to the heart is between 72% and 84%.7,8 As more physicians have become familiar with focused abdominal sonographic assessment for the evaluation of the trauma patient (FAST), cardiac tamponade has become somewhat easier to diagnose. Although the FAST technique is operator-dependent and at times limited by body habitus, excessive bowel gas, or open wounds, it serves as a rapid, noninvasive, and highly accurate diagnostic tool, which identifies life-threatening accumulations of blood in the pericardium or abdominal cavity.9 Although a learning curve is required, ultrasonography is very sensitive in detecting hemopericardium and is more specific than diagnostic pericardiocentesis, which carries a false-positive and false-negative rate of 6.4% and 19%, respectively.10 It is often wrongly stated that blood does not clot in the pericardium, yet many clinicians who care for trauma patients have observed clots in the pericardium, and the high false-negative rate of pericardiocentesis is often attributed to these clots.11 Cardiac ultrasonography has been found to have 98% accuracy, 97% specificity, and 90% sensitivity rates in detecting penetrating cardiac injuries.12 The mean examination time for a surgeon-performed cardiac ultrasound is 0.8 minutes.13 Studies have shown that echocardiography significantly reduces the time taken to diagnose cardiac or pericardial injuries and therefore confers a significant survival advantage.14

FAST was not performed in our case because the intra-abdominal wound was obvious and a celiotomy was necessary. Under these circumstances, a pericardial window is expeditious, safe, and accurate in identifying or excluding cardiac injury and is part of the trauma surgeon's armamentarium in the OR. In a series of 76 patients reported by Andrade-Alegre and Mon, no false-positives or negatives were reported with pericardial windows.15 The advantage of the pericardial window lies in its rapidity, safety, and accuracy, which is why it remains the gold standard in the evaluation of cardiac injuries. In our case, the injury created a pericardial window, but this was plugged by a visible clot intraoperatively. Given our clinical suspicion for a cardiac injury, the decision was made to obtain adequate exposure of the heart with an anterolateral thoracotomy in preparation for a cardiac repair. A median sternotomy would have been acceptable, as well. Although the patient's biventricular injury was repaired uneventfully, she encountered a rare and serious postoperative complication that often is not emphasized following penetrating cardiac injuries. A report discussing a level I trauma center's 22 years of experience with 192 penetrating cardiac trauma cases mentioned no incidence of an intracardiac thrombus.16

The postoperative complication of intracardiac thrombus with subsequent pulmonary embolization is serious and potentially life-threatening in an individual with an already compromised myocardium. Although one other case of ventricular thrombus complicating cardiac trauma has been described in the literature, there is no description of an intracardiac thrombus resulting in a pulmonary embolism following a gunshot wound to the heart.17 While cardiac evaluation for thrombus is most commonly done using two-dimensional echocardiography, our case demonstrates that CT scanning can be a useful adjunct, because it evaluates the chambers of the heart and the peripheral vasculature, allowing the lungs to be examined for emboli.

In the setting of our patient's biventricular injury, which consisted of a clot in the left ventricle and no evidence of DVT, it is likely that the pulmonary embolism originated from a clot in her right ventricle that dislodged to the lung parenchyma as an embolus. A clot seen intraoperatively at the apex of her heart was the initial operative finding that led to the high suspicion of a cardiac injury. There was no documentation of a ventricular septal defect in any of the diagnostic studies that were performed.

Conclusion

Penetrating cardiac trauma is among the most dramatic and lethal of all injuries. This case highlights the occasional subtle presentation of cardiac injuries and emphasizes the basic premise that a high index of suspicion for cardiac injury is necessary when injuries to the precordial region are identified. A better understanding of the modes of presentation and the diagnostic tools available will also lead to a rapid diagnosis and a better outcome. Following repair of a cardiac injury, close follow-up is needed, because significant complications can occur. These include the development of septal and valvular abnormalities and cardiac thromboembolism, as demonstrated by this case.

Disclosure

The authors have no relationship with any commercial entity that might represent a conflict of interest with the content of this article and attest that the data meet the requirements for informed consent and for the Institutional Review Boards.

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