Question of the Week 569
Authors: Maxwell James, MD – University of Mississippi Medical Center AND
Stephanie N. Grant, MD, FAAP – Emory University School of Medicine/ Children’s Healthcare of Atlanta
A six-month old female with hypoxemia and elevated mean pulmonary artery pressure (mPAP) is undergoing a diagnostic cardiac catheterization. She demonstrates reactivity during acute vasodilator testing with an improvement in hypoxemia and reduction of mPAP. For which of the following lesions is inhaled nitric oxide MOST LIKELY a beneficial treatment?
EXPLANATION
Pediatric pulmonary vein stenosis (PVS) is a rare disorder characterized by obstruction of the pulmonary veins. PVS can be categorized as postoperative surgical obstruction, anatomic obstruction, or intraluminal PVS. Postoperative surgical obstruction and anatomic obstruction result from external compression or angulated entry of pulmonary veins into the left atrium. Intraluminal PVS is characterized by obstruction due to neointimal growth into the lumens of pulmonary veins - often with relentless progression of disease leading to secondary pulmonary hypertension (pHTN), right heart failure, and death.1,2,3
Intraluminal PVS can be further categorized as primary PVS, PVS associated with congenital heart disease, or PVS associated with prematurity or chronic lung disease. However, “primary PVS” is often used to describe any case of intraluminal PVS not associated with prior surgical or catheter intervention. Given the rarity of this disease, the true incidence is difficult to determine, though studies estimate an incidence of 0.0017% to 0.03%.2,3 The etiology of this disease remains unclear, though myofibroblast deposition within the pulmonary vein walls is a common feature among all forms of intraluminal PVS.1,2 Intraluminal PVS is often associated with other cardiac defects and commonly occurs after repair of total anomalous pulmonary venous return (TAPVR).
In patients with pulmonary vein stenosis, any plan for sedation or general anesthesia warrants a thorough preoperative assessment of right ventricular function. Anesthetic management includes techniques to support the right ventricle and avoid increases in pulmonary vascular resistance. While it is prudent to avoid pulmonary vasodilator therapy in patients with certain forms of fixed distal obstructions - such as in TAPVR, mitral stenosis, and diffuse pulmonary vein stenosis - inhaled nitric oxide (iNO) may reduce pulmonary artery pressure and lead to clinical improvement in some patients with segments of lung affected by PVS.5 Case series of pediatric patients with segmental pulmonary vein stenosis and pHTN have demonstrated reactivity to acute vasodilator testing with iNO, suggesting a component of reversible pHTN.5 Presumably, blood flow into pulmonary veins with obstruction is redistributed to non-stenotic veins leading to elevated pulmonary venous pressure and the development of pulmonary arterial hypertension (PAH) in segments of the lung without pulmonary vein stenosis. In the early disease process, PAH is reversible, and patients demonstrate reactivity to acute vasodilator testing, leading to a decrease in mean pulmonary arterial pressure and pulmonary vascular resistance. Therefore, inhaled nitric oxide therapy is beneficial for a particular subset of patients with segmental pulmonary vein stenosis.4,5
Despite advances in medical, surgical, and catheter-based treatments, prognosis remains poor for patients with pulmonary vein stenosis. Restenosis occurs in the majority of patients, and long-term survival is rare.
REFERENCES
1. Nasr VG, Callahan R, Wichner Z, Odegard KC, DiNardo JA. Intraluminal Pulmonary Vein Stenosis in Children: A “New” Lesion. Anesthesia & Analgesia. 2019;129(1):27–40.
2. Vanderlaan RD, Rome J, Hirsch R, Ivy D, Caldarone CA. Pulmonary vein stenosis: Treatment and challenges. The Journal of Thoracic and Cardiovascular Surgery. 2021;161(6):2169–76.
3. Latson LA, Prieto LR. Congenital and Acquired Pulmonary Vein Stenosis. Circulation. 2007;115(1):103–8.
4. Domingo L, Magdo HS, Day RW. Acute Pulmonary Vasodilator Testing and Long-Term Clinical Course in Segmental Pulmonary Vascular Disease. Pediatr Cardiol. 2018;39(3):501–8.
5. Sokoliuk, V, DiNardo JA, Brown, M L. Never Say Never: The Use of Nitric Oxide in Patients With Obstructed Pulmonary Veins: A Case Report. A&A Practice. 2019; 12(6):205-207.