Unlike a true left ventricular aneurysm, the wall of the pseudoaneurysm does not contain endocardium nor myocardium. It is an incomplete rupture of the left ventricular wall enclosed by adherent pericardium and/or scar tissue [4, 6]. The outer layer of a true left ventricular aneurysm has the usual three tunics with intact [10] but thinned heart wall.
Left ventricular pseudoaneurysms are rare and potentially fatal. Their true incidence is unknown [11]. They are caused by myocardial infarction in most cases [4], while they are iatrogenic following previous cardiac surgery in 33% of cases [11]. Surgical procedures frequently associated with pseudoaneurysms include mitral valve replacement, aortic valve replacement, and correction of congenital heart disease [12]. For some authors, an infection is responsible in only 13% of cases [13].
In the presence of infectious disease, three mechanisms have been described for the formation of left ventricular pseudoaneurysms: septic coronary embolism leading to myocardial infarction and secondary rupture, dissemination from an adjacent perivalvular abscess, and seeding of the endocardium by a regurgitant jet [1, 7]. In our case, the pseudoaneurysm certainly developed in the postoperative course of valve surgery, but in a situation of an active infection, the exact mechanisms are not clear and can be common. Seeding of the left ventricular wall from an aortic perivalvular abscess or regurgitant jet that has escaped the operating team intraoperatively may be the likely cause, but iatrogenic origin cannot also be excluded. We believe that the left heart decompression cannula may have played a role in the development of the pseudoaneurysm in our patient. Its introduction through the right upper pulmonary vein and/or its replacement in the left ventricle after completion of the mitral valve repair for purging the left heart with its resulting tickling of an inflammatory endocardium can induce minimal wall trauma which progressed silently.
Regarding the clinical presentation, the revealing symptoms of pseudoaneurysm are variable and are not specific. The most common symptoms are chest pain and dyspnea [10]. Arrhythmias like junctional changeover as in our presentation are described in the literature [14]. On the other hand, the incidental discovery following transthoracic echocardiography is possible, and the proportion of asymptomatic patients varies between 10 and 48% according to studies [10]. In addition, the to-and-fro murmur which is the classic result of the physical examination is not constant (absent in our patient) and may be indistinguishable from an associated mitral regurgitation [4].
Although ventriculography remains the gold standard for the diagnosis of pseudoaneurysms [10], currently, with the advance of noninvasive techniques namely echocardiography despite its low sensitivity to detect pseudoaneurysms [15], computed tomography angiography of the chest and cardiac magnetic resonance imaging, this invasive examination has lost much of its indications. These noninvasive examinations can also guide management by suggesting the nature of the anomaly detected. If cardiac magnetic resonance imaging appears to be more helpful, its unavailability in case of emergency and its contraindication in many patients limit its use [14].
Current literature reports that 30–45% of ventricular pseudoaneurysms rupture within the first year, and therefore most authors have supported surgery as their appropriate treatment [4]. Surgical repair is the standard approach to treat left ventricular pseudoaneurysms with a reported mortality rate of 23% [4, 8]. The choice between direct or patch closure depends on the age of the pseudoaneurysm, the size of its neck, and its location. In our case, we were able to suture directly the defect, despite it being recent because it was narrow and the quality of the myocardial tissue surrounding it was good. However, a conservative approach may be recommended for asymptomatic patients and those with a higher risk of postoperative morbidity and mortality [10]. Recently, percutaneous closure has been reported as an alternative for high-risk surgical candidates [11, 16].