Acute Pulmonary Vasodilator Testing and Long-Term Clinical Course in Segmental Pulmonary Vascular Disease

Improving Outcomes in Pulmonary Vein Stenosis: Novel Pursuits and Paradigm Shifts

Pulmonary vein stenosis (PVS) remains a clinical challenge, with progressive restenosis being common. In the past five years, we have seen an exponential increase in both clinical and scientific publication related to PVS. Central to progress in PVS clinical care is the paradigm shift towards collaborative, multidisciplinary care that utilizes a multimodality approach to treatment. This manuscript will discuss recent conceptual gains in PVS treatment and research while highlighting important outstanding questions and barriers.

Management of Pediatric Pulmonary Vein Stenosis

Pediatric intraluminal pulmonary vein stenosis has evolved into a chronic illness, with improving survival. Although significant knowledge gaps remain, medical providers have found success in the management of patients with pulmonary vein stenosis using a comprehensive multimodality treatment strategy. This review discusses the core principles employed by 4 centers dedicated to improving pulmonary vein stenosis outcomes, including how to make the diagnosis, educating the family, treatment strategy, the importance of surveillance, and the management of symptoms and comorbidities.

Pulmonary Vein Stenosis in Children: A Programmatic Approach Employing Primary and Anatomic Therapy

Pulmonary vein stenosis (PVS) is a difficult condition to treat due to recurrence and progression. In 2017, we developed a comprehensive PVS Program at our center to address the multidisciplinary needs of these patients. We discuss the components of our program and our approach to these patients, using a combination of primary (medical) therapy in addition to anatomic therapy to preserve vessel patency. A multidisciplinary approach to treating these challenging patients is critical.

Intervening with the Nitric Oxide Pathway to Alleviate Pulmonary Hypertension in Pulmonary Vein Stenosis

Pulmonary hypertension (PH) as a result of pulmonary vein stenosis (PVS) is extremely difficult to treat. The ideal therapy should not target the high-pressure/low-flow (HP/LF) vasculature that drains into stenotic veins, but only the high-pressure/high-flow (HP/HF) vasculature draining into unaffected pulmonary veins, reducing vascular resistance and pressure without risk of pulmonary oedema. We aimed to assess the activity of the nitric oxide (NO) pathway in PVS during the development of PH, and investigate whether interventions in the NO pathway differentially affect vasodilation in the HP/HF vs. HP/LF territories. Swine underwent pulmonary vein banding (PVB; n = 7) or sham surgery (n = 6) and were chronically instrumented to assess progression of PH. Pulmonary sensitivity to exogenous NO (sodium nitroprusside, SNP) and the contribution of endogenous NO were assessed bi-weekly. The pulmonary vasodilator response to phosphodiesterase-5 (PDE5) inhibition was assessed 12 weeks after PVB or sham surgery. After sacrifice, 12 weeks post-surgery, interventions in the NO pathway on pulmonary small arteries isolated from HP/LF and HP/HF territories were further investigated. There were no differences in the in vivo pulmonary vasodilator response to SNP and the pulmonary vasoconstrictor response to endothelial nitric oxide synthase (eNOS) inhibition up to 8 weeks after PVB as compared to the sham group. However, at 10 and 12 weeks post-PVB, the in vivo pulmonary vasodilation in response to SNP was larger in the PVB group. Similarly, the vasoconstriction to eNOS inhibition was larger in the PVB group, particularly during exercise, while pulmonary vasodilation in response to PDE5 inhibition was larger in the PVB group both at rest and during exercise. In isolated pulmonary small arteries, sensitivity to NO donor SNP was similar in PVB vs. sham groups irrespective of HP/LF and HP/HF, while sensitivity to the PDE5 inhibitor sildenafil was lower in PVB HP/HF and sensitivity to bradykinin was lower in PVB HP/LF. In conclusion, both NO availability and sensitivity were increased in the PVB group. The increased nitric oxide sensitivity was not the result of a decreased PDE5 activity, as PDE5 activity was even increased. Some vasodilators differentially effect HP/HF vs. HP/LF vasculature.

Never Say Never: The Use of Nitric Oxide in Patients With Obstructed Pulmonary Veins: A Case Report

Pulmonary vein stenosis (PVS) is a progressive disease with pulmonary hypertension (PH) as a major cause of morbidity and mortality. Traditional management of PH with inhaled nitric oxide (iNO) is typically avoided in PVS patients because, while iNO may reduce pulmonary vascular resistance, PH persists as pulmonary blood flow increases in the presence of a downstream resistive lesion. We report 3 cases with primary PVS and PH in which iNO was used to successfully decrease mean pulmonary artery pressures with clinical improvement. Based on this experience, we suggest that iNO can be used to treat PH in select patients with PVS.