Biventricular Repair of Complex Congenital Left Ventricular Aneurysm

Karina Javalkar MD^1,2, Paul Esteso MD PhD^1,2, Rebecca S. Beroukhim MD^1,2

¹Department of Cardiology, Boston Children’s Hospital, Boston, MA, USA
²Department of Pediatrics, Harvard Medical School, Boston, MA, USA

Clinical History

A newborn infant male presented to the cardiac intensive care unit with a prenatal diagnosis of congenital left ventricular (LV) aneurysm and apical muscular ventricular septal defect (VSD). Prenatally, he had worsening LV function with fetal hydrops between 29-33 weeks gestational age. Hydrops resolved but LV systolic function remained severely depressed between 33-36 weeks gestation. Shortly after birth (36 weeks 6 days), he was electively intubated in the setting of known LV dysfunction. He developed low cardiac output syndrome with poor perfusion, and was transferred to our hospital’s cardiac intensive care unit. Echocardiogram showed a large apical LV aneurysm with severely depressed LV systolic function, as well as qualitatively moderate-to-severe right ventricular systolic dysfunction (Movie 1). He underwent cardiac catheterization which showed borderline cardiac output (cardiac index 2.5 L/min/m²), markedly elevated Qp:Qs of 3:1 related to the large apical VSD, and almost no contractility of the LV; nearly all contrast from the LV angiogram crossed the VSD into the pulmonary arteries, and there was minimal antegrade aortic blood flow (Movie 2). Coronary artery angiography showed normal coronary artery origins with unobstructed vessels. Therefore, the decision was made to proceed with initial transcatheter single ventricle palliation with a patent ductus arteriosus (PDA) stent and bilateral pulmonary artery (PA) flow restrictors. PA flow restrictors are an alternative to surgical pulmonary artery bands, in which a transcatheter microvascular plugs can be placed in the branch pulmonary arteries to restrict blood flow.[1,2]

Movie 1: Newborn echocardiogram subcostal sagittal view showing a large apical LV aneurysm.

Movie 2: Newborn LV angiogram demonstrating decreased LV systolic function and left to right flow across the VSD.

Cardiac magnetic resonance imaging (CMR) was obtained 2 weeks later in order to characterize the aneurysm and guide surgical planning. The patient subsequently underwent surgical conversion to a comprehensive stage 1, shunted circulation, with a Damus-Kaye-Stansel (DKS) anastomosis, modified Blalock-Taussig-Thomas (BTT) shunt, atrial septectomy and VSD closure. At the time of the surgical stage 1, he also underwent PDA stent and PA flow-restrictor removal, as well as LV aneurysm resection with the Dor technique.[3] He had persistent severe LV dysfunction, with the right ventricle, which also had significant dysfunction, supporting systemic output. He required tracheostomy in the setting of chronic respiratory failure and was finally discharged on an extensive oral heart failure regimen. In this setting, his LV systolic function improved over the course of a year.

Approximately 1 year following surgical stage 1, catheterization showed a normal cardiac index of 3.9 L/min/m², normal right- and left-sided filling pressures. LV end-diastolic pressure was 10 mmHg. A follow up CMR was obtained approximately 1 month following this catheterization in order to characterize his biventricular function, ventricular volumes, flows, and late gadolinium enhancement (LGE) imaging for consideration of biventricular repair. He subsequently underwent complex biventricular repair with takedown of his DKS and modified BTT shunt, PA and arch reconstruction, and atrial septation. Approximately 1 year following biventricular repair, he is clinically well with mildly depressed left and normal right ventricular systolic function. He remains on an oral heart failure regimen consistent of an angiotensin converting enzyme inhibitor and mineralocorticoid receptor antagonist.

CMR Findings

Initial CMR: CMR at 2 weeks of age, following transcatheter stage 1, showed a large LV apical aneurysm (Figure 1, Movie 3). The aneurysm involved the inferolateral and inferior segments at the mid and apical levels with hypokinesis of most of the affected segments. A small region at the apex was dyskinetic. The LV ejection fraction was calculated to be approximately 21%. There were 2 muscular septae protruding into the cavity, and significant hypokinesis and dyssynchrony of the ventricle. The right ventricular function was moderately depressed. LGE imaging showed basal anterior segment subendocardial enhancement, and apical inferior and lateral segment transmural enhancement (Figure 2). A 3D model was created in preparation for surgical Stage 1 and LV aneurysm resection (Figure 3).

Figure 1: Multi-plane (four chamber (a), two chamber (b), three chamber (c), short axis stack (d-f)) still frames of a large apical LV aneurysm (yellow arrows and asterisk) from cine SSFP series during initial CMR. There are 2 muscular septae protruding into the cavity as seen in panels a-c. The apex consists mostly of aneurysm tissue in panels d-f. Corresponds to Movie 3.

Movie 3: Muti-plane (four chamber (a), two chamber (b), three chamber (c), short axis stack (d-f)) cine SSFP demonstrating large apical LV aneurysm during initial CMR (corresponds to Figure 1).

Figure 2: Late gadolinium enhancement short axis stack images on initial CMR shows delayed enhancement in the basal anterior, apical inferior and lateral segments.

Figure 3: 3D model of large apical LV aneurysm (arrows).

Follow up CMR: CMR was again obtained at 1 year after surgical aneurysm resection (Dor procedure) and Stage 1 with modified BTT shunt insertion, in preparation for biventricular repair (Figures 4 and 5, Movie 4). There was no residual LV aneurysm and mildly depressed global LV systolic dysfunction with regional apical hypokinesis. The LV ejection fraction on this study was 43%, and LV end-diastolic volume index was 64 mL/m[2] . There was a moderately dilated RV with moderately depressed function (EF 34%). The LV was contributing to 40% of cardiac output at the time of this study, and Qp:Qs was 1.22. There was aortopoulmonary collateral burden of approximately 20% of aortic flow. Additionally, there was patchy LGE in multiple areas of the RV, with areas of subendocardial and transmural enhancement that worsened towards the apex, associated with hypokinesis. In the LV, there was hypokinesis and subendocardial LGE in the mid-LV and apex, at the site of aneurysm resection. There was also transmural enhancement of the apical inferior and lateral segments.

Figure 4: Multi-plane (four chamber (a), two chamber (b), three chamber (c), short axis stack (d-f)) still frames from cine SSFP imaging on follow up CMR obtained 1 year after initial surgery. CMR shows no residual LV aneurysm and normal RV and LV volumes from 4-chamber, 2-chamber and short axis views. Corresponds to Movie 4.

Movie 4: Multi-plane (four chamber (a), two chamber (b), three chamber (c), short axis stack (d-f)) cine
SSFP from follow up CMR obtained 1 year after initial surgery (corresponds to Figure 5).

Figure 5: Late gadolinium enhancement short axis stack image on follow up CMR shows extensive delayed enhancement throughout both ventricles. Panels a-c show the basal segments with less extensive, but present LGE. Panels d-f show substantial LGE in the apical segments.

Conclusion

We present a pediatric case of a rare congenital LV aneurysm with associated VSD that required initial single ventricle palliation prior to complex biventricular repair. This novel single ventricle palliation approach was undertaken in order to support LV aneurysm resection and allow for recovery of the LV myocardium. Initial CMR provided detailed evaluation of ventricular function, regional dyskinesis, and aneurysm characterization, and 3D modeling was used for surgical planning. CMR findings after initial stabilization with a PDA stent and PA-flow restrictors were used to guide decision-making to pursue a surgical stage 1 procedure concomitantly with LV aneurysm resection.

The patient was monitored clinically and by echocardiography in the interim to determine optimal timing for biventricular conversion. With this approach, the patient’s biventricular systolic function improved with time and oral heart failure therapies. The development of worsening cyanosis and reassuring function prompted further evaluation for consideration of biventricular conversion. Additionally, understanding the challenges of single ventricle physiology in the setting of tracheostomy dependence, there was additional indication to move towards a biventricular circulation when possible.[4,5] CMR at that time was used for accurate assessment of ventricular volumes, cardiac output, regional and global function, and fibrosis. He was discussed at our institution’s biventricular repair multidisciplinary conference in which he was deemed appropriate for repair. CMR findings were key in determining readiness for biventricular repair, including volumes, lack of residual LV aneurysm, and percentage of combined ventricular output provided by the LV. The patient successfully underwent a biventricular repair without additional interventions needed thus far. He continues on an oral heart failure regimen, with remaining dyskinesia primarily at the LV apex. His most recent echocardiogram (2 months following biventricular repair) shows qualitatively normal RV systolic function and LV ejection fraction of 52%. (Movie 5)

Movie 5: Echocardiogram short axis mid-ventricular view obtained 2 months following biventricular repair, demonstrating mild global LV systolic dysfunction.

Perspective

LV aneurysms and diverticulae are rare malformations first identified in the 1800s with ~800 cases in the literature.[6] LV aneurysms are characterized as a dyskinetic sac-like outpouching from the LV, thought to be due to idiopathic endomyocardial dysplasia.[7] Congenital LV outpouchings are often prenatally diagnosed by echocardiography. The vast majority of congenital LV aneurysms present with a hemodynamically stable biventricular circulation. A small proportion of patients can develop thrombosis, arrhythmia, congestive heart failure, mitral regurgitation, aneurysm rupture, or sudden death[8–11] . When LV aneurysms are diagnosed, congenital aneurysms must be differentiated from potential acquired causes.[12] Non-congenital causes of LV aneurysms in children can include myocardial infarction, prior cardiac surgery, trauma, Chagas disease, and tuberculosis[7] . In this case, we discuss the diagnosis and management of congenital LV aneurysms. The most common associated congenital cardiac abnormalities with LV aneurysms cited in the literature include coronary anomalies, VSD, and atrial septal defects.[12] In our patient, the presence of the aneurysm prenatally excluded infectious and traumatic causes. There was an associated VSD. Coronary anomalies were ruled out on catheterization and coronary angiography shortly after birth, although this would not completely rule out a neonatal infarct.

Medical management of LV aneurysms is focused on targeting congestive heart failure, and preventing thromboembolism. Surgical treatment when patients are symptomatic, as in the case of our patient, may include aneurysm resection or plication.[7,13] The Dor procedure, described by Dor et al in 1989, and most commonly used in adult patients with LV aneurysms, is comprised of three components: (1) resection of the dyskinetic or akinetic LV free wall aneurysm and thrombectomy if needed at that time; (2) Dacron patch used to exclude the akinetic regions; and (3) myocardial revascularization of the left anterior descending artery performed as needed.[3,14,15] The initial study of the Dor procedure suggested improved outcomes compared to more traditional linear closure of the LV; however, data is limited in use of this surgical technique in children with congenital LV aneurysms.

A wide range of imaging modalities are useful in the diagnosis and management of LV aneurysms. Initial diagnosis can be made on both fetal and postnatal transthoracic echocardiography. 3D echocardiography can be helpful in calculating LV aneurysm volumes.[16] Tissue Doppler and strain assessments can aid in identification of dyskinetic segments.[17] However, depending on echocardiographic windows, small apical changes can be missed if the apex is unable to be fully visualized.[10] Angiography may be needed to confirm coronary artery anatomy and patency, and left ventriculograms can be useful to assess the continuity between the LV and the aneurysm (i.e. to differentiate from a pericardial tumor), identify thrombus and assess for areas of dyskinesis.[10,12] Cardiac CT, an alternative to CMR for the evaluation of congenial ventricular aneurysms, are well suited to identify anatomic details of the aneurysm as well as associated non-cardiac abnormalities.[18,19] CMR has emerged as a useful modality in the management of congenital LV aneurysms as it can provide both anatomic and functional details needed for clinical assessment and surgical planning.[20]

With numerous strengths in tissue characterization, assessment of ventricular volumes and function, and the ability to quantify flow, CMR is an ideal imaging strategy for patients with congenital LV aneurysms. In the pediatric population, myocardial viability by CMR has been shown to correlate well with coronary angiography and segmental wall motion abnormalities.[21] Tissue characterization of the aneurysm and adjacent myocardium provided by CMR, which allows for assessment of myocardial perfusion and scar, can help guide decision for surgery and operative strategy, as well as aid in predicting postoperative outcome after biventricular conversion.[22] Volumetric assessment of the aneurysm by CMR provides a baseline with which aneurysms can be followed over time. Given the abnormal geometric morphology of the ventricle in this condition, CMR is the most accurate way to quantify LV volumes and ejection fraction. Furthermore, CMR allows for identification of regional dyskinesis and akinesis related to the aneurysm. The 3D models produced from source angiograms are highly instrumental in visualization of the aneurysm morphology, and for guiding surgical planning. In addition, quantification of cardiac output with flow measurements, and assessment of surrounding structures (i.e. mitral and aortic valves) leads to a comprehensive cardiac assessment. One limitation of CMR – the inability to image distal coronary arteries (which have been implicated in development of LV aneurysms) – can be mitigated by coronary angiography, as was done in our case.

For our patient, who underwent a staged approach to biventricular repair, CMR also provided critical information guiding subsequent medical and surgical planning after the Dor procedure. As a complement to echocardiography and hemodynamic data by catheterization, CMR provided wall motion assessment, LV volume, and ejection fraction which helped to determine readiness for biventricular repair. LGE identified subendocardial scar tissue that has implications in our patient’s risk for adverse outcomes in the short and long term.[22]

In summary, congenital LV aneurysms are rare abnormalities that may carry a poor prognosis, and therefore require comprehensive assessment of anatomy and tissue characterization to guide management. We described a case of a large congenital LV aneurysm that required multimodality imaging to guide a novel, staged surgical technique that ultimately resulted in a biventricular circulation without significant complications at present. CMR is useful for initial anatomic and functional assessment and surgical planning, and should be further explored as a tool for follow up and prognostication of patients who have undergone LV aneurysm resection.

Click here to view the initial CMR on CloudCMR.

Click here to view the follow-up CMR on CloudCMR.