Huge Morgagni Hernia, a Rare Criterion to Favor TAVI Against SAVR

Abstract

Transcatheter aortic valve implantation is now a validated treatment option for severe aortic stenosis in patients in whom surgical aortic valve replacement is recommended, especially those associated with an elevated surgical risk. Here, we discuss the surgical management of a case of severe aortic stenosis in a patient with huge Morgagni hernia. (Level of Difficulty: Beginner.)

Central Illustration

History of Presentation

A 75-year-old man presented with worsening exertional dyspnea (NYHA functional class III) over the last 2 years. However, he denied orthopnea or paroxysmal dyspnea, nor did he have any episodes of angina or syncope. On presentation, his vital signs were stable. His cardiovascular examination revealed a grade 4/6 ejection systolic murmur. Respiratory and abdominal examinations were unremarkable.

Learning Objectives

• •To be able to diagnose the cause of worsening dyspnea in a patient with a multitude of respiratory and cardiac comorbidities.
• •To understand the role of TAVI as an alternative to SAVR in patients with complex surgical conditions.

Past Medical History

The patient was being managed conservatively for a stable Morgagni diaphragmatic hernia, which was diagnosed in 2017. He has obstructive sleep apnea for which he uses a continuous positive airway pressure machine regularly. He was diagnosed with interstitial lung disease (ILD) secondary to hypereosinophilic syndrome. From a cardiac perspective, the patient has known coronary artery disease and he received multiple drug-eluting stents in 2017 to his right coronary artery and left main stem. His past medical history was significant for type II diabetes mellitus, arterial hypertension, peripheral neuropathy, and obesity (body mass index of 38 kg/m²).

Differential Diagnosis

The differential diagnosis for his presentation includes progression of Morgagni diaphragmatic hernia, worsening of ILD, or worsening of his aortic stenosis (AS).

Investigations

A computed tomography (CT) scan of the chest showed a stable huge Morgagni hernia that extended through the anterior mediastinal space up to the level of the aortic arch (Figure 1). His most recent pulmonary function tests showed a forced expiratory volume in 1 second of 1.8 L, an forced expiratory volume in 1 second/forced vital capacity of 0.72, and a diffusing capacity for carbon monoxide of 13.6, suggestive of a restrictive pattern probably owing to a combination of obesity, the diaphragmatic hernia, and ILD. However, these values have remained stable over the last few years. His transthoracic echocardiogram and cardiac CT scan showed heavily calcified aortic valve leaflets (Figures 2 and 3) with AS (aortic valve area: 0.80 cm²; aortic valve area index: 0.36 cm²/m²; peak gradient: 60 mm Hg; mean gradient: 29 mm Hg; and dimensionless index: 0.25) with preserved left ventricular ejection fraction (67%), mild left ventricular (LV) hypertrophy (LV posterior wall thickness: 1.2 cm; LV septal thickness: 1.3 cm; and LV mass index: 118 g/m²) with decreased LV cavity (LV end-systolic volume index: 14 mL/m²; LV end-diastolic volume index: 41 mL/m²; and LV stroke volume index: 37 mL/m²), mild left atrial enlargement (left atrial dimension: 4.5 cm; left atrial volume index: 36 mL/m²), and elevated left side pressures (pulmonary capillary wedge pressure: 39.5 mm Hg). On admission, his B-type natriuretic peptide plasma level was 153 ng/L. Coronary angiography showed patent coronary stents and no new flow-limiting lesions.

Figure 1.

CT Scan Showing a Large Morgagni Hernia

A large Morgagni hernia containing transverse colon extending through the mediastinum to the level of the aortic arch in an (A) axial and (B) sagittal views. CT = computed tomography.

Figure 2.

Cardiac CT Scan

There is evidence of severe aortic valve calcifications along all 3 commissural margins.

Figure 3.

Transthoracic Echocardiogram

(A) Long and (B) short axis views of the left ventricle demonstrating evidence of severe aortic valve leaflet calcifications.

Management

The case was discussed by the heart team, and it was thought that the patients’ recent symptomatic deterioration was probably attributed to his AS rather than worsening ILD or expanding diaphragmatic hernia. The consensus was that the patient presented with severe low-gradient AS with normal left ventricular ejection fraction or paradoxical low-flow severe AS. This finding was supported by his echocardiographic and radiologic findings in the context of an elevated B-type natriuretic peptide and in absence of any recent significant deterioration in the patient’s recent pulmonary function tests or progression of his hernia on serial imaging. His calculated Society of Thoracic Surgeons intraoperative risk was 3%. After multidisciplinary discussion, it was agreed that, owing to his massive retrosternal extension of the diaphragmatic hernia, transcatheter aortic valve implantation (TAVI) would be a more favorable option as compared with surgical aortic valve replacement (SAVR). His CT angiogram for preprocedural planning showed measurements adequate for a transfemoral approach and suitable aortic root anatomy for TAVI. The patient underwent transfemoral TAVI with a balloon-expandable valve (Edwards Sapien 3; size 26 mm). There were no intraprocedural complications. Intraoperative and predischarge echocardiography confirmed a well-seated functioning valve with no evidence of paravalvular leak (peak/mean gradients: 19/10 mm Hg) and he was discharged home on postoperative day 2.

Discussion

Morgagni hernia is a rare diaphragmatic defect in the adult life that accounts for approximately 3% of congenital diaphragmatic hernias.¹ Most cases are congenital, but it can also be acquired secondary to iatrogenic injury or chest or abdominal trauma.^2,3 Although most patients are asymptomatic, progressive herniation of the abdominal contents into the thoracic cavity can cause worsening dyspnea, retrosternal chest pain, and rarely cardiac tamponade.² Complications include bowel strangulation and incarceration and, thus, it is recommended that large hernias be repaired to prevent these serious complications.¹

Only a few case reports in literature have been published regarding the diagnosis and suggested management of aortic valve pathology in patients with Morgagni hernia.3, 4, 5 Most studies reported concomitant SAVR and hernia repair with good postoperative outcomes.3, 4, 5

If a staged procedure is planned, SAVR typically occurs first, because severe symptomatic AS is acutely more life threatening than an uncomplicated diaphragmatic hernia.⁵ Also, from the general anesthesia point of view, undergoing a major procedure to repair a huge diaphragmatic hernia in patients with untreated severe symptomatic AS can incur a risk of cardiac decompensation.⁵

Similarly, performing SAVR in patients with residual untreated diaphragmatic hernia may increase the risk of some perioperative complications such as profound respiratory compromise, acid-base imbalance, and hemodynamic instability.⁶ Postoperative ileus is common after cardiac surgery and, in the context of a diaphragmatic hernia, can lead to an increased risk of bowel obstruction, incarceration, and strangulation.⁷ Furthermore, mediastinal adhesions resulting from the first surgery of a staged procedure can increase the intraoperative risk during chest re-entry.⁵ For all these reasons, a concomitant procedure has been generally preferred to a staged procedure.⁵

However, concomitant surgeries may be associated with perioperative morbidity owing to the prolonged operative times increasing risk of wound infection, bleeding, and respiratory compromise.⁸ Additionally, there is a risk of bowel perforation owing to the retrosternal location of the Morgagni hernia—the occurrence of which can result in surgical field contamination and the potential risk for prosthetic or surgical wound infections.⁹

Regarding the order by which concomitant procedures are performed, although Nenekidis et al³ suggested performing SAVR before the hernia repair, Huang et al⁴ recommended performing the hernia repair before pericardiotomy, which ensures a sterile field for the subsequent cardiac surgery. Some studies recommended performing the hernia repair before initiating the cardiopulmonary bypass to help avoid postcardiopulmonary bypass sequelae, such as hemodynamic instability and coagulopathy, which can increase the risk of the hernia repair.^4,5

In the present case report, the patient has a low intraoperative mortality risk as estimated by the Society of Thoracic Surgeons risk calculator, and the use of TAVI was felt to be more beneficial than SAVR owing to the presence of a huge Morgagni hernia. This strategy avoids the associated intraoperative risk of concomitant hernia repair and SAVR, including the clinical sequelae of a prolonged operative time. Furthermore, TAVI has been shown to provide a reliable option as compared with SAVR in patients with respiratory compromise,¹⁰ as was the case for our patient.

Follow-up

The patient remained clinically stable with significant symptomatic improvement on follow-up 6 months after the procedure and his most recent B-type natriuretic peptide plasma level has decreased to 105 ng/L.

Conclusions

This case report highlights the value of TAVI as a valid option to SAVR in patients with complex surgical conditions to reduce the likelihood of developing perioperative complications.