Role of extracorporeal membrane oxygenation in the management of myocarditis during caesarean birth

Summary

We describe a pregnant patient who presented in labour with diffuse ST‐segment elevation on electrocardiography and biochemical evidence of myocardial injury. Transthoracic echocardiography showed severe biventricular dysfunction. An urgent caesarean birth was indicated due to breech presentation and severe cardiac dysfunction. Intra‐operatively, the ventricular function worsened requiring escalating vasopressor administration and the patient developed refractory monomorphic ventricular tachycardia. After delivery, she progressed to cardiogenic shock and required urgent veno‐arterial extracorporeal membrane oxygenation cannulation with subsequent axillary Impella 5.5 (Abiomed, Johnson & Johnson MedTech; Danvers, MA, USA) placement for left ventricular unloading. She received immunosuppressive therapy for suspected fulminant myocarditis. Her haemodynamics improved and ventricular function normalised over 12 days of extracorporeal membrane oxygenation support. She was weaned from mechanical circulatory support, her trachea was extubated and an implantable cardioverter‐defibrillator was placed. She was discharged home neurologically intact with complete biventricular recovery. The case emphasises the importance of early recognition of rapid haemodynamic decline and timely initiation of mechanical circulatory support in an acute setting.

Introduction

Cardiovascular disease remains one of the leading causes of maternal mortality in the USA [1]. Acute myocarditis is an uncommon but potentially catastrophic cause of acute ventricular failure, characterised by inflammatory myocardial injury leading to severe systolic dysfunction, arrhythmias and cardiogenic shock [2, 3, 4]. Viral infections remain the most common aetiology [2]. During pregnancy and the peripartum period, physiological cardiovascular changes increase myocardial workload and may exacerbate inflammatory injury, predisposing the patient to electrical instability and haemodynamic collapse [2, 5].

Fulminant myocarditis frequently presents with ventricular tachyarrhythmias, conduction abnormalities and biventricular failure, resulting in refractory shock and multi‐organ dysfunction [2, 3]. Diagnosis relies on clinical features, biomarkers, ECG and echocardiography with confirmatory cardiac magnetic resonance imaging (MRI) and endomyocardial biopsy findings [3, 4]. Early recognition and timely escalation of supportive therapy are essential to prevent irreversible myocardial and end‐organ injury.

Veno‐arterial extracorporeal membrane oxygenation (VA‐ECMO) provides effective temporary circulatory support for patients with fulminant myocarditis and potentially reversible cardiac failure [6]. Increasing experience with ECMO use in pregnant and peripartum patients demonstrates favourable maternal outcomes when initiated promptly within a multidisciplinary framework [6, 7, 8]. However, reports describing the use of VA‐ECMO during emergency caesarean birth for myocarditis‐associated ventricular arrhythmia and haemodynamic collapse remain limited.

Report

A 25‐year‐old nulliparous woman with BMI 26 kg.m⁻² and a past medical history of asthma presented to the obstetric unit at 39‐weeks' gestation with regular contractions. She was promptly scheduled for an urgent caesarean birth due to a footling breech presentation. Further inquiry revealed a recent history of intermittent palpitations and a presyncopal episode associated with symptoms of a viral upper respiratory tract infection one week earlier. On arrival, she had tachycardia up to 134 beats.min⁻¹ with blood pressure of 100/67 mmHg; she was dyspnoeic and peripherally oedematous but denied any chest pain. Electrocardiography revealed diffuse ST‐segment elevations (Fig. 1). Administration of adenosine briefly slowed the ventricular rate, revealing underlying P‐waves with persistent ST‐segment elevations. The fetal heart rate was reassuring, with intermittent minimal to moderate variability and tachycardia up to 180 beats.min⁻¹.

Figure 1.

Initial electrocardiogram demonstrating diffuse ST‐segment elevation.

Laboratory testing suggested marked myocardial injury with a serum troponin of 22.28 ng.ml⁻¹, creatinine kinase‐myocardial band of 80.6 ng.ml⁻¹ and pro‐BNP of 6306 pg.ml⁻¹. Liver enzymes were also mildly elevated. Bedside transthoracic echocardiography suggested global hypokinesia with a left ventricular ejection fraction (LVEF) of 20–25% and severely reduced right ventricular function. Emergency coronary angiography prior to surgery demonstrated normal coronary arteries with no acute findings.

Given the breech presentation, progressing cervical dilatation and worsening haemodynamic instability, an urgent caesarean birth was performed under general anaesthesia. Prior to induction of anaesthesia, an external defibrillator and pacing pads were applied. The patient was positioned supine with left uterine displacement and a noradrenaline infusion commenced. General anaesthesia was induced using midazolam 2 mg, etomidate 6 mg, lidocaine 100 mg and suxamethonium 100 mg, followed by noradrenaline boluses in 16 μg increments and initiation of an adrenaline infusion at 0.03 μg.kg⁻¹.min⁻¹. A low‐dose propofol infusion combined with sevoflurane was used to maintain anaesthesia. Rocuronium was administered for ongoing neuromuscular blockade.

A healthy neonate was delivered, and immediately after cord clamping, an infusion of oxytocin 30 IU was administered over 60 minutes while a central line was placed and vasopressors were then administered centrally. Intra‐operative transoesophageal echocardiography performed by a cardiac anaesthetist showed progressive biventricular dysfunction and new severe mitral regurgitation. During abdominal closure, the patient developed sustained monomorphic ventricular tachycardia (Fig. 2) refractory to boluses of lidocaine, amiodarone and magnesium; two attempts at synchronised cardioversion with energy of 120 J and 200 J resulted in only transient sinus rhythm. Despite favourable uterine tone and modest intra‐operative blood loss estimated at 470 ml, the patient required escalating doses of adrenaline, noradrenaline, vasopressin and dopamine.

Figure 2.

Electrocardiogram demonstrating ventricular tachycardia.

With worsening cardiogenic shock suspected, cardiothoracic surgical assistance was sought. Emergency femoral VA‐ECMO cannulation was undertaken under echocardiographic guidance and a distal perfusion catheter placed. ECMO flows were adequate with 100% oxygenation. Due to subsequent minimal pulsatility overnight, an axillary Impella 5.5 device (Abiomed, Johnson & Johnson MedTech; Danvers, MA, USA) was placed to aid left ventricular unloading and inhaled nitric oxide added for right ventricular support. The patient was anticoagulated with a bivalirudin infusion after ECMO cannulation, with a target activated partial thromboplastin time (aPTT) of 60–80 s.

On postoperative day 1, the patient developed complete heart block and required temporary transvenous pacing. A therapeutic regimen for suspected fulminant myocarditis was initiated, including high‐dose methylprednisolone with taper, intravenous immunoglobulin, a single dose of anti‐thymocyte globulin and ciclosporin targeting a level of 150 ng.ml⁻¹. The LVEF initially decreased to 10% but gradually improved with the return of pulsatility. By hospital day 12, LVEF had recovered to 55–60%, allowing successful VA‐ECMO decannulation. The patient was subsequently placed on prophylactic antimicrobial therapy including sulfamethoxazole‐trimethoprim, acyclovir and valganciclovir.

An implantable cardioverter‐defibrillator was placed for secondary prevention and endomyocardial biopsy performed to rule out giant cell myocarditis. Results showed patchy chronic inflammation consistent with myocarditis, with lymphocytes and histiocytes present, yet no evidence of eosinophils or giant cells. Cardiac magnetic resonance imaging showed no epicardial enhancement. The patient was discharged home neurologically intact, at her functional baseline, with complete biventricular recovery.

Discussion

This patient rapidly progressed to sustained ventricular tachycardia (VT) and cardiogenic shock intra‐operatively. There are multiple factors which contributed to this patient's clinical decline. Her left ventricular dysfunction and underlying myocardial dysfunction due to myocarditis likely acted as a substrate for arrhythmia. In the setting of critical illness, she had a catecholaminergic or sympathetic surge associated with the surgical stimulus which could have triggered a VT storm. Although rare, refractory VT storm in peripartum cardiomyopathy is associated with poor outcomes when circulatory support is delayed [2, 6]. Auto‐transfusion after placental delivery can precipitate cardiovascular collapse; however, in this case the arrhythmia occurred during fascial closure rather than immediately after delivery of the placenta, suggesting a multifactorial cause of her deterioration [9].

While rapid boluses of oxytocin can cause hypotension, our institutional standard of 30 IU of diluted oxytocin administered over 60 minutes would likely not have contributed significantly to the patient's underlying instability. Our institutional practice is to transition to a combination of propofol infusion and inhalational agent to avoid significant uterine hypotonus.

Early VA‐ECMO was initiated after global hypokinesia with biventricular failure was suggested on transthoracic and subsequently transoesophageal echocardiography. Prompt circulatory support allowed an opportunity for anti‐arrhythmic therapy, metabolic optimisation and immunosuppression. The Impella 5.5 device is increasingly recognised as an adjunct to ECMO and was used here to enable left ventricle unloading, reduce ventricular distension and risk of intracardiac thrombus and support myocardial recovery [6, 10].

High‐dose intravenous immunoglobulin (IVIG) has been proposed as a treatment for acute myocarditis because of anti‐inflammatory and immunomodulatory effects [3, 4]. Two clinical trials evaluating IVIG have yielded inconclusive results, potentially due to heterogeneity in patient selection and dosing regimens [3, 4]. While immunosuppression is strongly recommended in specific non‐infectious myocarditis subtypes, the role of steroids in viral myocarditis remains controversial [4]. In our patient, empiric immunosuppressive therapy was initiated before biopsy results were available because of the patient's critical illness. The severity of her haemodynamic instability precluded early cardiac magnetic resonance imaging or endomyocardial biopsy.

This case highlights the importance and potential of early recognition and timely escalation to mechanical circulatory support in pregnant and peripartum patients with refractory shock or malignant arrhythmias [8, 11]. The Seventh National Audit Project (NAP7) found that the leading cause of cardiac arrest in obstetric patients was haemorrhage; however, high neuraxial block and bradyarrhythmia were also listed as causes of cardiac arrest [11]. Mechanisms for this include inferior vena cava compression by the gravid uterus and bradyarrhythmia related to spinal anaesthesia and decreased venous return [11]. Protocol‐driven early initiation of VA‐ECMO may reduce the risk of irreversible end‐organ injury and support myocardial recovery. In centres without on‐site ECMO capability, temporary mechanical circulatory support devices, such as a femoral Impella CP device (Abiomed, Johnson & Johnson MedTech; Danvers, MA, USA) or an intra‐aortic balloon pump, may be considered as a bridge to definitive support, with careful consideration of anticoagulation strategies in the peripartum period [6, 10]. In this case, bivalirudin was used due to its short half‐life compared to heparin, which allows for quicker titration and minimises the patient's exposure to heparin.

Emerging machine learning models designed to predict the need for rescue VA‐ECMO may further aid early identification of high‐risk patients [6, 10]. Early recognition of clinical deterioration, clearly defined triggers for escalation, stabilisation prior to inter‐hospital transfer and standardised referral pathways are all essential components of safe and effective care. The development of structured checklists for critically ill patients requiring transfer and early consideration of cannulation by a mobile ECMO team may stand to improve outcomes further.