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Blunt thoracoabdominal trauma is most often caused by high-velocity motor-vehicle accidents or by falls from a height. The clinical spectrum of cardiac injuries arising from this type of trauma varies from myocardial contusion to valvular rupture. Intracardiac valvular rupture is rarely observed, and few cases have been reported. The youngest of the patients in cases reported to date was 6 years of age. Here we report the case of a 2½year-old child, who sustained mitral valve insufficiency due to isolated rupture of the posterior mitral papillary muscle, which developed after a domestic accident.
Blunt thoracoabdominal trauma is most often caused by high-velocity motor-vehicle accidents or by falls from a height,1 and the clinical spectrum of cardiac injuries arising from this type of trauma varies from myocardial contusion to aortic rupture. Intracardiac valvular rupture is rarely observed with this type of trauma, and few cases have been reported.
In July 2006, a 2½-year-old boy presented with nausea, vomiting, and subxiphoid pain after a 21-inch television fell on his thorax and abdomen. Before the onset of these symptoms, he had lost consciousness for 5 to 10 min. On auscultation, we heard a 4/6 pansystolic murmur through the anterior and posterior walls of the thorax. Transthoracic 2-dimensional (2-D) echocardiography revealed structurally normal mitral valve leaflets, but the posterior leaflet moved freely and prolapsed into the left atrium during systole; therefore, the mitral valve could not coapt. Severe mitral insufficiency was seen (Figs. 1, ,22 and and3).3). No other thoracoabdominal injury appeared on radiologic evaluation or on clinical follow-up.
Surgical repair of the mitral valve was chosen after consultation between staff members of pediatric cardiology and cardiovascular surgery. After performing a left atriotomy, we filled the left ventricle with a cooled 0.9% solution of sodium chloride, which confirmed severe prolapse of the posterior mitral leaflet into the left atrium. We then used pledgeted 3-0 polypropylene sutures to reattach the torn papillary muscle of the left posterior mitral valve to its primary position. During intraoperative testing, however, the leaflets of the mitral valve still did not coapt properly, so we performed a quadrangular resection of the posterior leaflet. Even so, minimal leakage was observed through the mitral valve; therefore, we performed mitral annuloplasty with a strip of autogenous pericardium 2.5 cm long and 2 mm wide, affixed by five 6-0 polypropylene sutures. The operation was terminated after proper coaptation of the mitral leaflets was confirmed by visual inspection. Mitral insufficiency was not observed during echocardiography performed in the operating room, so the patient was transferred to the intensive care unit.
The patient stayed in the intensive care unit for 1 day, with no complication. When transferred to the clinic, he had a heart rate of 96 beats/min, with sinus rhythm, and a blood pressure of 115/70 mmHg. Follow-up echocardiography performed on the 3rd postoperative day revealed 1st-degree mitral insufficiency that extended from the region of mitral coaptation to the interatrial septum (Fig. 4). The peak mitral gradient was 11 mmHg, and the mean gradient was 5.5 mmHg. The patient experienced no adverse sequela and was discharged on the 6th postoperative day.
Traumatic rupture of papillary muscle was first reported by Glendy and White in 1936,2 and the 1st successful repair of a mitral valve after blunt trauma was performed by McLaughlin and colleagues in 1964.3 The most common cardiac valve injuries due to this type of trauma are aortic valve lesions, followed by mitral and tricuspid lesions.4 Aortic valve injuries are seen in early ventricular diastole, whereas tricuspid and mitral valve injuries can be detected in late diastole or at the beginning of systole.1,4 The most common type of mitral valve injury after blunt trauma is rupture of the papillary muscle. This is followed in incidence by rupture of the chordae tendineae and leaflets. Our patient sustained a mitral papillary muscle rupture caused by blunt thoracic trauma. Aortic valve lesions tend to occur as the tearing of a single aortic cusp, frequently the noncoronary cusp torn from the anulus.5
Valvular injury must be suspected after blunt cardiac trauma when the examining physician detects acute or progressive cardiac insufficiency, or a new cardiac murmur. The clinical spectrum of symptoms may range from none at all to cardiogenic shock. As in the case of our patient, asymptomatic mitral valve injury may progress (due to stress on the wall) to complete rupture of the valvular apparatus and exacerbation of symptoms. Consequently, treatment must be started without delay.
Clinical signs determine the timing of mitral valve replacement or repair. Decisions on timing and choice of technique are made in consideration of the location of the injury, the presence of accompanying injuries, the time elapsed between the injury and the operation, and the experience of the surgeon. Because our patient was 2½ years old, valve replacement would likely have led to anticoagulation complications and, more certainly, to subsequent operations (for the placement of larger valves) as the patient grew. Therefore, we chose primary repair of the ruptured papillary muscle, quadrangular resection of the posterior leaflet, and posterior mitral annuloplasty with a pericardial strip. Use of a pericardial strip for mitral annuloplasty has been shown to preserve anatomic and physiologic properties of the mitral annulus and to provide better long-term results.6
In autopsies of 546 fetuses with nonpenetrating cardiac injuries, Parmley and colleagues7 were unable to detect a mitral lesion in isolation, but they did find 8 cases of mitral valve rupture in combination with other cardiac injuries. To our knowledge, nearly 40 cases of traumatic mitral valve injury treated by surgical repair have been reported in the medical literature. In our research, the youngest patient was 6 years of age.4 We have presented the case of a 2½-year-old boy who sustained, in isolation, a mitral papillary muscle rupture consequent to blunt thoracic trauma.
Patients who have experienced blunt thoracic trauma must undergo meticulous physical examination and echocardiographic imaging in an effort to detect cardiac injuries, which include possible intracardiac valvular lesions.
Address for reprints: Mehmet Guzeloglu, MD, Department of Cardiovascular Surgery, Dokuz Eylul University, Inciralti, 35340 Izmir, Turkey. E-mail: moc.liamtoh@ulgolezugtemhem