Neuraxial anesthesia in Lutembacher’s syndrome? Yes, we can!

ABSTRACT

Lutembacher’s syndrome is a rare congenital cardiac syndrome comprising of a combination of an atrial septal defect complicated by congenital or acquired mitral stenosis. The applied physiology of the patient depends upon the severity and the interactions of the lesions. They pose certain difficulties to the administration of both general or neuraxial anesthesia. A preference of one form of anesthesia over the other should be based on the understanding of the physiology of the patient. There should not be an orthodox avoidance of neuraxial anesthesia in complex cardiac pathologies as general anesthesia can be associated with certain complications of its own. Here, we report our successful experience of neuraxial anesthesia being administered in a patient with Lutembacher’s syndrome.

Introduction

Lutembacher’s syndrome is a rare syndrome comprising of a combination of an atrial septal defect (ASD) complicated by congenital or acquired mitral stenosis (MS).[1] Hemodynamic changes in these patients depend on the interplay between the relative effects of ASD and MS. A fixed cardiac output state and the presence of pulmonary arterial hypertension (PAH) make administering neuraxial anesthesia challenging in these patients as it is associated with a reduction in systemic vascular resistance (SVR). We hereby share our successful experience of administering neuraxial anesthesia in a patient with Lutembacher’s syndrome.

Case Report

A 54-year-old male patient came to our hospital for bilateral inguinal hernia repair. He had been previously diagnosed with a 13-mm Ostium Secondum ASD and moderate MS with severe PAH. The left ventricular ejection fraction was 35% without any evidence of thrombus in any chamber of the heart. Preoperative interrogation revealed a heart rate of 90 bpm with stable hemodynamics. All the necessary rescue devices were kept ready in the operating room (OR). After confirming pre-anesthetic instructions, the patient was shifted to the OR. Standard American Society of Anesthesiologists (ASA) monitors were attached and the patient was administered oxygen by venturi mask. A peripheral intravenous catheter (18 G), an arterial catheter (20 G, right radial artery), and a central venous catheter (7 F, right internal jugular vein) were placed. A preloading bolus of intravascular fluids was avoided. Strict air-bubble precautions were followed to prevent any accidental paradoxical air embolism. The patient was positioned in the right lateral position. Under all aseptic precautions and infiltration anesthesia, an 18-G epidural catheter was placed at the L3–L4 intervertebral level using the loss of resistance technique. Then, a subarachnoid block was administered in the same intervertebral space. A total of 1.7 mL of drug was administered constituting of 1.2 mL of 0.5% bupivacaine heavy and 25 mcg (0.5 ml) of fentanyl using a 26-G Quincke spinal needle. Surgical anesthesia was achieved, and the level of the block was confirmed to be T10.

There was an isolated episode of hypotension (blood pressure = 89/45 mmHg, mean arterial pressure = 60 mmHg). It was managed by an intravenous bolus of 25 mcg of phenylephrine. A mean arterial pressure greater than 65 mmHg and a heart rate between 60 and 100 bpm were targeted. The intravenous fluids were administered at the rate of 60 mL/h. Perioperative echocardiography was performed to assess the volume status at preinduction and after regional anesthesia [Figures 1–3, Videos 1 and 2].

Figure 1.

Transthoracic apical four-chamber view showing (a) severe tricuspid regurgitation, and (b) right ventricular systolic pressure of 41.1 mmHg from the tricuspid regurgitation jet

Figure 3.

Apical four-chamber view showing a large atrial septal defect (yellow arrow)(yellow arrow)

Figure 2.

Apical five-chamber view showing a left ventricular outflow tract velocity time interval of 14.9 cm

The low-dose subarachnoid anesthesia was supplemented by epidural administration of 0.5% ropivacaine in a graded manner. After 60 minutes of administration of subarachnoid block, two aliquots of 3 mL of 0.5% preservative-free ropivacaine were administered in a time span of 10 minutes. It was not associated by any hemodynamic fluctuation. The surgical anesthesia lasted for a duration of 2 hours and 30 minutes. At the end of the surgery, the patient was shifted to recovery with stable hemodynamics. The patient was transferred to a high dependency unit for overnight monitoring of hemodynamics and subsequentially discharged to home.

Discussion

Severity of Lutembacher’s syndrome can range from an isolated mild MS to severe MS with PAH.[2] The hemodynamic alterations in these patients mainly depend on the size of the ASD and MS severity, which can further be complicated by the development of PAH and right ventricular failure. As MS becomes severe, the left atrium blood finds exit through the ASD resulting in left atrial decompression. This process delays the development of pulmonary venous hypertension. On the other hand, PAH develops early due to excessive pulmonary blood flow which can lead to right ventricular failure in the long run.

Administration of general anesthesia in these patients itself can be associated with an unpredictable perioperative course. The sympathetic surge during intubation can precipitate hemodynamic instability by reducing diastolic filling time, resulting in low left ventricular stroke volume. Also, an increase in the pulmonary vascular resistance (PVR) due to hypoxia, hypercarbia, and hypothermia can worsen right ventricular dysfunction, further compromising the forward flow and resulting in acute decompensation if left untreated. Mechanical ventilation in these patients is associated with complex cardiopulmonary interactions. The transition from a positive pressure ventilation to a negative pressure ventilation during a hastened weaning attempt can create unfavorable loading conditions for the heart and potentially entails acute cardiac decompression.[3]

Administration of neuraxial anesthesia in these patients can be associated with different complications. Although neuraxial blockade has been used safely in patients with PAH, blocking cardiac sympathetic fibers in the upper thoracic region disrupts the right ventricular homeometric autoregulation. When inhibited, it can lead to a critical reduction in cardiac output and right heart failure that is not due to impaired right ventricular coronary flow dynamics or systemic vasodilation.[4] Therefore, neuraxial blockade involving the upper thoracic region should be practiced with caution.

PAH coupled with a fixed cardiac output state owing to severe MS make these patients prone to developing hemodynamic instability in response to vasodilation. The hypotension is caused by a decrease in SVR in this patient population. It should not be treated by an overzealous use of intravenous fluids as they have a fixed cardiac output. A judicious use of vasopressors is thus a better management strategy to tackle this hypotension. The choice of vasopressors depends on their effect on PVR-to-SVR ratio. The use of norepinephrine and vasopressin may reduce the PVR-to-SVR ratio more than the high doses of phenylephrine.[5] In fact, low-dose vasopressin actually decreases PVR by enhancing the release of nitric oxide from the pulmonary vascular endothelium and V₂ receptor activation in vascular smooth muscles.[6] It is important for the anesthesiologist to understand the pathophysiology of Lutembacher’s syndrome thoroughly for the optimal intraoperative management of these rare pathologies. The best strategy is to always aim at maintaining higher systemic pressures than pulmonary pressures, irrespective of the anesthetic technique.

The postoperative goals are appropriate management of pain, targeting lower heart rate, adequate oxygenation, and normothermia. Prevention of arrythmias is key. Few patients with significant hemodynamic instability, refractory hypoxemia, or hypercarbia at the end of surgery may require postoperative monitoring in an intensive care unit. These patients may have prolonged ventilatory requirements and higher morbidity and mortality.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given his consent for his images and other clinical information to be reported in the journal. The patient understands that his name and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.