TUBE, Transesophageal Echocardiography, Transversus Abdominis Plane Block, and Team-Work: Peripartum Cardiomyopathy with Ejection Fraction 20% Managed “To the T”

INTRODUCTION

With continued improvement in maternal care world-wide, peripartum morbidity and mortality is on a decreasing trend. However, peripartum cardiomyopathy (PPCM), a heart failure (HF) associated with pregnancy of unknown etiology, ranging in incidence from 1 in 1149 to 4350 in United States,^[1] is a leading cause of maternal death in the peripartum period.^[2] The most acceptable proposed mechanism is the unbalanced oxidative stress and high levels of prolactin.^[3] Anesthesia management for these patients, especially with severely reduced cardiac function, can prove to be a herculean task to the extent of mechanical circulatory support (MCS) requirement in the perioperative period.^[4] We, hereby, report a case of a multi-co-morbid PPCM patient with the left ventricular (LV) ejection fraction (EF) 20 % for elective lower-segment cesarean section (LSCS).

CASE REPORT

A 36-year-old female (Gravida 2, Abortion 1) presented at 30 weeks of gestation with swelling of both legs progressing to generalized edema since 2 months with breathlessness on exertion (New York Heart Association III) since 5 days. She was a known case of bronchial asthma, also diagnosed with gestational hypothyroidism and gestational diabetes mellitus, and controlled on medication. She was also a reformed smoker. On investigations, NTpro brain natriuretic peptide was elevated to 2563 pg/mL. On transthoracic 2D echocardiography, left atrium (LA), left ventricle (LV), and right atrium were dilated. The LV was globally hypokinetic with EF of 15–20%. The right ventricular function was also reduced with tricuspid annular plane excursion (TAPSE) of 12 mm. There were severe mitral regurgitation (MR) and moderate tricuspid regurgitation (TR). Considering the prevailing condition in the background of pregnancy, she was diagnosed as a case of PPCM. The acute congestive HF was controlled with tablets furosemide, hydralazine + isosorbide, carvedilol, digoxin, and injection low-molecular-weight heparin (LMWH). Despite of stabilization for over 4 weeks, the decreased cardiac function and “precious pregnancy” status prompted for elective LSCS at 34 weeks weighing 70 kg. Pre-operative hemoglobin was 13.5 g/dL, HbA1c – 5.6% with normal thyroid function. The Mallampati grade was II with adequate mouth opening. The chest was clear with systolic murmur on the precordium. Considering the risk of acute decompensation, the case was planned to be carried out in cardiac surgical operation room (OR). LMWH was stopped 12 h before surgery, furosemide was withheld on the day of surgery, other drugs were continued with injection pantoprazole 40 mg, and metoclopramide 10mg administered 30 min before shifting to the OR. Informed/written high-risk consent was obtained from the patient.

In the OR, patient was made to lie supine with a wedge kept underneath the right hip. Five-lead electrocardiogram, noninvasive blood pressure (BP), and pulse oximetry (SpO₂) monitoring were instituted. Under local anesthesia, 20 gauge (G) peripheral intravenous (IV) line was placed on the left hand. Right radial artery and ultrasound-guided (USG) right internal jugular vein was cannulated with 20 G cannula and 7.5 French lines, respectively. The baseline heart rate (HR) was 120/min, invasive BP – 140/80 mmHg, respiratory rate – 22/min, central venous pressure (CVP) – 19 cm H₂O, and SpO₂ – 98% on room air (RA). Baseline arterial blood gas (ABG) showed pO₂ of 80 mmHg. Adrenaline and noradrenaline infusions were connected to the central venous line. Considering the possibility of intra-procedural cardiovascular collapse, the cardiac surgery team was also scrubbed in with concomitant readiness of perfusionist with veno-arterial extracorporeal membrane oxygenation (VA-ECMO) circuit standby. The pediatrician was also prepared with radiant warmer and neonatal resuscitation devices. Patient was painted and draped along with the bilateral femoral areas for emergency peripheral VA-ECMO cannulation. The plan of action was to institute femoral VA-ECMO in the event of cardiac collapse. General anesthesia (GA) was induced with etomidate 0.2 mg/kg and succinylcholine 2 mg/kg with application of Sellick’s maneuver. After induction of anesthesia, HR and BP were near baseline values. Trachea was intubated with 7.5 mm endotracheal tube with C-MAC video-laryngoscope. During intubation, HR and BP increased to 136/min and 158/90 mmHg, respectively. After intubation, the peak airway pressure increased to 35 cm H₂O, which subsided with salbutamol puffs. Transesophageal echocardiography (TEE) probe was also inserted. Intraoperative TEE findings were concurrent with the pre-operative findings of LA dilatation, severe LV dilatation, and dysfunction with EF 16%. However, MR had reduced to moderate severity [Figures 1a and b, 2a]. Systolic blunting of “S” wave was noted in the left pulmonary vein pulse-wave Doppler [Figure 2b]. Anesthesia was maintained with sevoflurane in air-oxygen mixture and vecuronium. After cesarean delivery of the baby, injection oxytocin 5 U diluted in 20 mL normal saline was administered over 10 min, additional 15 U were added to 150 mL normal saline in burette set and infused over 1 h. IV fentanyl 50 ug was given after clamping the cord. After delivery of baby, HR was 110/min and BP was 114/79 mmHg. The appearance, pulse, grimace, activity, and respiration score was 7 and 9 at 1 min and 5 min, respectively. Post-uterine closure TEE showed no further decrease in contractility or increasing MR/TR. After skin closure, HR was 106/min, BP – 104/79 mmHg, and CVP – 14 cm H₂O. The patient did not require any inotropes/vasopressors during surgery. USG bilateral transversus abdominis plane block (TAPB) was given with 40 mL 0.2% ropivacaine mixed with dexamethasone 8 mg and dexmedetomidine (DEX) 0.75 µg/kg. Injection paracetamol 1 g was also administered. Total intraoperative fluid administered was 300 mL Ringer’s lactate with urine output of 75 mL. There were no rales/rhonchi on auscultation. On resumption of spontaneous breathing efforts, neuromuscular blockade was reversed with neostigmine and trachea was extubated in OR. Patient was shifted in propped up position with oxygen supplementation to cardiac intensive care unit (CICU). HR of 80/min, BP – 108/70 mmHg, CVP reduced to 12 cm H₂O, and SpO₂ 100% on face mask with 5 L/min flow were measured in CICU with visual analog scale (VAS) score of 2. ABG revealed pO₂ of 117 mmHg, hematocrit 40 % without acidosis. The patient was monitored for the next 24 h in CICU. The CICU stay was uneventful, the patient was shifted to ward and discharged after 10 days.

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Figure 1:

(a) Trans-esophageal echocardiography 2D image in mid-esophageal four-chamber view at 00 shows dilated LA, dilated, and globular LV. The LA measures 4.39 × 4.51 cm signifying dilatation. (b) M-mode image in trans-gastric mid-papillary view at 00, showing measurement of LV internal diameter in systole and diastole − 5.98 cm and 6.49 cm respectively, which are severely dilated. The fractional shortening is calculated to 7% and ejection fraction of 16%, indicating severe dysfunction. RA: Right atrium, RV: Right ventricle, LA: Left atrium, LV: Left ventricle, LVIDs: Left ventricular internal diameter in systole, LVIDd: Left ventricular internal diameter in diastole.

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Figure 2:

(a) Mid-esophageal four-chamber color Doppler image showing moderate central mitral regurgitation jet reaching in the left atrium associated with globular left ventricular. (b) Pulsed-wave Doppler in mid-esophageal two-chamber view probing the left pulmonary vein, showing blunting of “s” wave, suggestive of moderate mitral regurgitation. RA: Right atrium, RV: Right ventricle, LA: Left atrium, LV: Left ventricle.

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DISCUSSION

The European society of cardiology has defined PPCM as an idiopathic cardiomyopathy frequently presenting with HF secondary to LV systolic dysfunction (LVEF < 45%) toward the end of pregnancy or in months following delivery. Diagnosis of PPCM may be delayed, as HF symptoms can be confused with symptoms of normal pregnancy. The plan for mode of delivery, anesthesia, invasive hemodynamic monitoring, and requirement of MCS should be discussed in a multi-disciplinary team meet at the first contact with patient.^[5]

Anesthesia management for severely reduced systolic function with EF < 20% should be done on a case-based assessment. Regional anesthesia (RA) in the form of spinal anesthesia (SA), continuous SA, epidural anesthesia (EA),^[6] and combined spinal EA^[7] have been used for LSCS in PPCM.^[8] Graded EA has been preferred due to gradual reduction in systemic vascular resistance (SVR), decreasing the preload and afterload to the failing heart.^[9] The sympathetic nervous system is maximally stretched in HF with generalized vasoconstriction along with salt and water retention. Any further sudden decrease in SVR is avoided with use of GA, facilitated by induction with etomidate. In a patient with orthopnea and severe preeclampsia for emergency LSCS under SA, developed loss of consciousness, shock, acute respiratory failure, and cardiac arrest requiring acute cardiac life support with intubation and was subsequently diagnosed as having EF 25–30%.^[10] Emergency LSCS and severely decompensated HF mandates GA. Florid pulmonary edema and fetal distress in a case of PPCM required performance of LSCS under GA, intraoperative pink frothy sputum and increasing oxygen requirement could be well managed with endotracheal tube in situ.^[11] In another case with EF 28%, pre-induction acute cardio-respiratory deterioration required emergency tracheal intubation.^[12] A recent meta-analysis comprising 403 case reports providing 466 cases from 48 countries described, patients with PPCM are at risk of rapid unpredictable deterioration. It also states mortality in 5–6% patients and its association with LVEF <30%. Although, it concludes that neither of the anesthetic techniques have a discernible impact on outcome.^[13] Another case series also report no link between anesthetic intervention and postpartum deterioration.^[14] Maintenance of preload, contractility, afterload, and avoiding tachycardia form the goals of induction irrespective of the choice of anesthesia. In our case, GA was administered considering the severity of LV dysfunction. It also provided the added advantage of secured airway avoiding emergency intubation in the event of hemodynamic collapse, ease of insertion, and performance of TEE. Response to laryngoscopy can be blunted by opioids with the attending risk of neonatal intubation and mechanical ventilation. Awake insertion of central venous line was done to promptly start inotropic support in the event of hemodynamic instability at induction. Pulmonary artery catheter (PAC) can be used to monitor the hemodynamic changes with also being helpful for post-operative management since fluid-shifts continue to occur post-delivery. PAC was used to aid in planning delivery in a case of recurrent PPCM patient with EF 10%.^[15] However, its invasiveness and decreasing trend in use of PAC limited its use in our patient. Furthermore, the use of TEE providing structural and functional view of the heart superseded PAC in our case.

TEE is an excellent tool for intraoperative real-time hemodynamic monitoring.^[16] It aids in deciphering the exact cause of hemodynamic instability – hypovolemia, decreasing systolic function of LV/RV, increasing MR/TR, decision to institute ECMO, rule out intra-cardiac thrombus/PFO, facilitate correct position of peripheral ECMO cannulas, and requirement of LV venting.^[17,18] TEE in our case enabled us to confirm the stability of cardiac function and guided in estimation of intraoperative volume status and fluid replacement. In-sights into cardiac decompensation was visualized by TEE in a PPCM patient undergoing LSCS under EA with pre-operative EF 35%. Intraoperative echo found decline in EF to 20–25% with severe MR which required dobutamine and colloid resuscitation.^[19] In a recent study of investigations of pregnancy-associated cardiomyopathy, RV dysfunction was present in one-third of patients and was associated with worse outcomes including death, transplant, and LV assist device (LVAD) implantation.^[20] A 32 year previously undiagnosed patient, post vaginal delivery required LVAD after EF reduced to 10% and subsequently bi-ventricular assist device for RV dysfunction, complicated by cerebral infarct and a large thrombus in aortic root detected by TEE.^[4] Our patient also had RV dysfunction, measured by TAPSE <16 mm. Our choice with the use of stand-by VA-ECMO was superior since it provides biventricular circulatory support vis-à-vis intra-aortic balloon pump or LVAD. Femoral micropuncture catheters can be placed providing conduit to swiftly change over to ECMO cannulas.^[21] Right radial artery should be cannulated for accurate assessment of saturation being supplied to brain in femoral VA-ECMO, as was done in our case.^[22,23] Dobutamine stress echocardiography at initial presentation has been shown to correlate with recovery of LV contractile function and can be used for risk stratification.^[24]

The auto-transfusion occurring post cord clamping from contracted uterus and release of inferior venacaval compression can cause acute volume overload in a tenuous hemodynamic situation. Oxytocin should be administered slowly to avoid hypotension. Contraction of uterus should be ensured, avoiding the use of methyl-ergometrine with its risk of tachycardia and hypertension.

A major disadvantage with GA is absence of post-operative pain reduction obtained with RA. Post-operative pain can cause tachycardia and increase SVR, raising the myocardial oxygen demand. Considering the history of asthma, nonsteroidal anti-inflammatory drugs (NSAIDs) were avoided to mitigate the risk of its exacerbation. Regional analgesia with TAPB can provide effective pain control in the immediate post-operative period where NSAIDs and opioids are contraindicated. IV infusion of DEX in HF with reduced EF decreases mean arterial pressure.^[25] Addition of DEX to local anesthetic is known to improve the duration of analgesia. Although, DEX added to TAPB in dose of 1–1.5 ug/kg has been found to have systemic side-effect of bradycardia, there is a dose-dependent reduction in stress response measured by serum cortisol, interleukin-6, epinephrine, and norepinephrine.^[26] Control of HR plays a seminal role in management of HF. Numerous studies and trials have reported a direct relationship between resting HR and mortality.^[27] In our case, the use of 0.75 ug/kg dose could also have been systemically absorbed to cause beneficial decrease in HR to 80/min observed in CICU, although for a moderate duration of time aiding in to recuperate in the post-delivery period. This case report highlights the novel role of DEX in chronic HF administered through regional block in the perioperative period to decrease HR along with conscious-sedative effect and “pain-free” patient observed post-extubation.

Intensive monitoring of hemodynamics, respiration, saturation, and vigilance in the post-operative period is equally important for detection of any signs of decompensation and need for institution of MCS in refractory cardiogenic shock.

CONCLUSION

The mode of anesthesia depends on the emergency of LSCS and severity of PPCM. Anesthesiologist should be actively involved in the multi-disciplinary team managing a patient with PPCM. Pre-operative optimization in an elective case, formulation of an individualized plan, intraoperative hemodynamic monitoring with echocardiography, and careful attention in the post-operative period paves way for a safe peripartum period.