VSD in a kyphoscoliotic child: A perilous liaison!

To the Editor,

Congenital heart disease (CHD) often manifests as a component of multisystemic syndrome with the coexisting pathologies demonstrating the potential of compounding the underlying disease.[1] We describe the perioperative course of a 3-year-old kyphoscoliotic child posted for the surgical closure of the ventricular septal defect (VSD) wherein the interaction between the vertebral anomaly and CHD with the subsequent impact on the management is discussed.

The child presented to our hospital with chief complaints of recurrent chest infections for 2 years. On evaluation, transthoracic echocardiography revealed a large perimembranous VSD with severe pulmonary arterial hypertension (PAH). The preoperative X-ray demonstrated severe thoracic kyphoscoliosis [Figure 1a]. Cardiac catheterization was performed preoperatively which outlined a pulmonary vascular resistance index (PVRI) of 7 wood unit/m2 with a positive acute vasoreactivity test.[2] Albeit a positive vasoreactivity, a high baseline PVRI in a patient with a combination of pulmonary pathology (owing to kyphoscoliosis) and a CHD (with increased pulmonary blood flow) implied a high-risk operative setting.

Figure 1

An image panel depicting severe thoracic kyphoscoliosis with enhanced bronchovascular markings in the chest X-ray (a); large perimembranous ventricular septal defect in mid-esophageal 4-C view, transesophageal echocardiographic examination performed with S7-3t probe and Philips Healthcare 7Q Elite ultrasound machine (Bothell, WA) (b); and pre-cardiopulmonary bypass (CPB) and post-CPB comparative presentation of the systemic and pulmonary arterial pressures (c and d), respectively

Anesthesia was induced and maintained following a standard institutional protocol. Intraoperative transesophageal echocardiography (TEE) performed with S7-3t probe and Philips Healthcare 7Q Elite ultrasound machine (Bothell, WA), depicted left to right shunt across the VSD with a gradient of 10 mmHg and a significant left ventricular volume overload [Figure 1b]. The main pulmonary artery (PA) was dilated and tense on surgical palpation. Needle transduction revealed near systemic PA pressure [Figure 1c]. Phenoxybenzamine in a dose of 0.5 mg/kg was administered intravenously after aortic cannulation. Subsequently, a VSD patch closure was performed with the cardiopulmonary bypass (CPB) time of 85 min and aortic cross-clamp duration of 51 min under adequate heparinization and mild hypothermia. Considering severe preoperative PAH, milrinone and adrenaline infusions were initiated in a dose of 0.5 mcg/kg/min and 0.05 mcg/kg/min, respectively at rewarming, anticipating difficult weaning. Following a safe separation from CPB, modified ultrafiltration (MUF) was contemplated. The post-CPB PA pressure was almost half as compared to the systemic pressure [Figure 1d]. Heparin was reversed with a 1:1 dose of protamine administered slowly in the background of vigilant monitoring for any characteristic signs of post-CPB pulmonary hypertensive (PH) crisis (hypoxemia with high airway pressure, hypotension with high right atrial pressure and/or tachycardia with ischemic signs in right-sided ECG leads).[3] The postoperative TEE demonstrated a satisfactory surgical closure of the VSD with a mildly impaired right ventricular (RV) function (RV- fractional area change of 28% and tricuspid annular plane systolic excursion of 17 mm). Moreover, a patent foramen ovale (PFO) was surgically created to decompensate RV in a situation of declining ventricular performance at the cost of systemic desaturation. The arterial oxygen tension/fractional inspired oxygen concentration (PaO2 /FiO2) ratio steadily improved post-procedurally and the patient was extubated after 12 h of intensive care unit (ICU) stay.

Varying degree of PAH is inexorably associated with large nonrestrictive VSD. It is noteworthy that the kyphoscoliosis related pathophysiology could have accentuated the VSD related PAH in the index case which is supported by the existing evidence on the cardiopulmonary consequences of the vertebral anomaly. An exemplary study by Caro et al. revealed elevated PA pressure in subjects with kyphoscoliosis.[4] The coexisting PAH in kyphoscoliosis can be explained by the resultant restrictive ventilatory pattern (causing diminished lung volumes and enhanced ventilation-perfusion mismatch), alveolar hypoventilation culminating as systemic hypoxemia and hypercarbia which are well-known to increment RV afterload.[5] However, the degree of PAH contributed by the pulmonary pathology and the extent of PAH emanating as a result of VSD could not have been delineated in the present clinical context of a pediatric patient precluding the performance of a pulmonary function test. Despite the aforementioned fact, the index association incurred a heightened risk of postoperative PH crisis and/or difficult CPB-weaning. VSD closure in a setting of VACTERL syndrome (vertebral column anomalies, anal atresia, congenital heart defects, tracheoesophageal defects, renal and distal urinary tract anomalies, and limb abnormalities) has been described in the literature.[6] Nevertheless, this is a novel discussion of the liaison between the concomitant pathologies with regards to the management principles in this rare cohort of patients wherein the inclusion of the tenets of a multipronged anesthetic-perfusion-surgical approach individualized to the case scenario (anti-inflammatory measures, normothermic CPB, MUF, prophylactic ionodilators, PFO, open pleurae, lung-protective ventilation, and other pharmacological anti-PAH strategies including postoperative phosphodiesterase inhibitors and/or inhaled NO) is pivotal for ensuring favorable outcome.

To conclude, the case highlights that PAH is essentially a multifactorial syndrome, elucidating the importance of meticulous perioperative planning accounting for the pathologies which could complicate the CHD associated PAH. As it is aptly said: To be forewarned is to be forearmed and half the victory…

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Conflicts of interest

There are no conflicts of interest.