Introduction

Posterior left ventricular pseudo-aneurysm (LVP) is a rare and insidious condition, difficult to diagnose and to treat. It is generated by the rupture of the posterior ventricular wall contained by the pericardium, which blocks the bleeding and the consequent cardiac tamponade. Several causes have been described, the most common of which is myocardial infarction. The second most common cause of LVP is previous surgery, in particular mitral valve replacement; in literature, it is reported as a cause of LVP in a percentage from 0.02 to 2% [1]. Lesser causes are heart trauma and infections.

Case Presentation

A 61-year-old patient was referred to the Department of Cardiology of our Hospital for the presence of severe exertional dyspnea, NYHA functional class III. Two years before, he underwent mitral valve replacement with a mechanical prosthesis for the presence of severe mitral insufficiency due to Staphylococcus aureus infective endocarditis, treated with six weeks of specific antibiotic therapy. About 2 months later, the patient had removed the mechanical prosthesis for valve thrombosis due to incorrect management of anticoagulation therapy, and a Carpentier Edwards Magna Ease 27 mm bio-prosthesis was implanted. The post-operative course was uneventful and the patient was discharged on the seventh post-operative day after an echocardiogram that highlighted the correct position and function of the mitral prosthesis. Subsequently, the patient remained asymptomatic for 2 years; then, he began to complain of dyspnea, which progressively worsened; surface echocardiogram and then a trans-esophageal demonstrated the correct functioning of mitral bio-prosthesis in presence of a left ventricle pseudo-aneurysm (LVP) of about 6 cm maximum diameter determining a total end-diastolic volume of 267 ml (LVP volume 135 ml). Cardiac synchronized multi-detector computed tomography (MDCT) was then useful to better characterize the pathology, and it confirmed the presence of the pseudo-aneurysm, with the neck just adjacent to the edge of the mitral prosthesis; the overall size of LVP was 7.6 × 7.4 × 6 cm. Along the external profile, LVP was demarcated by a scar tissue of about 0.5 cm thick. The neck measured 2.5 × 2.2 cm and was not visible any thrombus inside the LVP that was close to the right ventricle and right atrium; collaterally, MDCT did not highlight critical coronary disease (Fig. 1). At this point, surgery was planned, and through a longitudinal median sternotomy, extracorporeal circulation has begun by cannulation of ascending aorta and right atrium by femoral percutaneous vein; the posterior and inferior surface of the heart was cleaved by the surrounding structures after initiating extracorporeal circulation to hold the ventricles. LVP was then opened allowing access to its cavity and visualization from the inside of the neck, which in the cranial portion lay behind the mitral prosthesis. The consistency of the left ventricular wall at the LVP neck has allowed us to perform the implantation of a dacron patch to close it. The patch was sutured with 2–0 Prolene U-stitches with pledgets in the area adjacent to the mitral prosthesis, while the remaining perimeter was sutured with a 3–0 Prolene running suture. Successively, the LVP external wall was closed covering the patch to complete the hemostasis. The mitral prosthesis appeared in excellent conditions confirming what has been seen through ultrasound examination. The patient was easily disconnected from the extracorporeal circulation and the post-operative course was uneventful. A trans-esophageal echocardiogram was performed in five post-operative days and confirmed the suitable surgical result with the absence of residual pseudo-aneurysm and preserved good shape and global kinesis of the left ventricle. Chest tomography at 3 months from operation showed a good surgical result (Fig. 2).

Fig. 1
figure 1

Three-dimension cardiac synchronized tomography showing left ventricle pseudo-aneurysm. A four-chamber view; B short-axis view showing the neck of the pseudo-aneurysm; C two-chamber view showing the proximity of left ventricle pseudo-aneurysm with mitral prosthesis

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Fig. 2
figure 2

Three-dimension cardiac synchronized tomography 3 months after surgical repair of left ventricle pseudo-aneurysm. A Coronal view. B Axial view. C sagittal view

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Discussion

LVP after replacement of the mitral valve complicates the post-operative course of this intervention at a percentage between 0.02 and 2.0% [1, 2]. Several causes may determine a rupture in the posterior wall of the left ventricle post-mitral surgery, such as the presence of endocarditis with or without abscess, the need for extensive decalcification of the annulus, and the placement of a valve oversized. From the few works in the literature on the subject, it emerges that the formation of LVP is facilitated by the presence of coronary heart disease with myocardial infarction [3]. LPA after mitral valve replacement usually occurs from a few days to a few weeks after the surgery. In our case, 2 years have passed between the surgery and the diagnosis of LPA, and although there is a temporal correlation, causality cannot be directly established. The onset in our case may have been delayed due to the repeated stress of the mitral valve over a back ventricular wall already weakened. But the rupture may have occurred even shortly after the intervention and then with time the LPA has increased considerably. Due to a poor trans-thoracic echocardiographic window and the absence of symptoms, the diagnosis may have been delayed. The main symptoms in presence of LVP are dyspnea and chest pain, although in 10% of cases, it can be asymptomatic and diagnosis occurs at a post-operative echo [4]. There are also changes in electrocardiogram and widening of the cardiac shadow to the chest x-ray, but the instrumental investigations that best allow diagnosis are echocardiography, including trans-esophageal, cardiac tomography or magnetic resonance (MRI), and angiography. Angiography allows a good view of the size of the sac around the left ventricle and the size of the neck, and assesses the presence of coronary occlusion. MDCT and MRI allow you to delimit the contours of LVP and relationships with other cardiac structures, as well as measuring the distance of the neck from the mitral prosthesis (MP). The only therapeutic solution for LVP is represented by surgery, since leaving this untreated would mean a volumetric increase and a 30 to 45% of rupture risk [5]. Elective surgery is at high risk, with a mortality ranging from 10 to 23%, and requires optimal planning based on the characteristics of the pseudo-aneurysm. Sternotomy access allows better control of LVP, especially when by large size, and troubles derived from the presence of adhesions. Closure of LVP has been described without opening the cardiac cavities, but suturing the wall from the outside with Teflon reinforced Prolene points [6]. Alternatively, access may be performed by left mini-thoracotomy at the fifth intercostal space, avoiding exposure of the lesion by retracting the heart [7]. The planning of this operation was crucial, through the interpretation of cardiac tomography with three-dimensional reconstruction and angiography.

Conclusions

Right diagnosis and structural characterization are of crucial importance in the management of LVP, and they must be supported by instrumental investigations such as MDCT and trans-esophageal echocardiography. The correct surgical strategy should be selected based on clinical presentation and anatomy, taking into account the causes that led to the genesis of pseudo-aneurysm. Surgery is burdened by high mortality, but when diagnosis is done, it must be performed to avoid the risk of breakage.