The State of the Art in Pulmonary Vein Stenosis -Diagnosis & Treatment

Patient-specific 3D in vitro modeling and fluid dynamic analysis of primary pulmonary vein stenosis

Introduction

Primary pulmonary vein stenosis (PVS) is a rare congenital heart disease that proves to be a clinical challenge due to the rapidly progressive disease course and high rates of treatment complications. PVS intervention is frequently faced with in-stent restenosis and persistent disease progression despite initial venous recanalization with balloon angioplasty or stenting. Alterations in wall shear stress (WSS) have been previously associated with neointimal hyperplasia and venous stenosis underlying PVS progression. Thus, the development of patient-specific three-dimensional (3D) in vitro models is needed to further investigate the biomechanical outcomes of endovascular and surgical interventions.

Methods

In this study, deidentified computed tomography images from three patients were segmented to generate perfusable phantom models of pulmonary veins before and after catheterization. These 3D reconstructions were 3D printed using a clear resin ink and used in a benchtop experimental setup. Computational fluid dynamic (CFD) analysis was performed on models in silico utilizing Doppler echocardiography data to represent the in vivo flow conditions at the inlets. Particle image velocimetry was conducted using the benchtop perfusion setup to analyze WSS and velocity profiles and the results were compared with those predicted by the CFD model.

Results

Our findings indicated areas of undesirable alterations in WSS before and after catheterization, in comparison with the published baseline levels in the healthy in vivo tissues that may lead to regional disease progression.

Discussion

The established patient-specific 3D in vitro models and the developed in vitro-in silico platform demonstrate great promise to refine interventional approaches and mitigate complications in treating patients with primary PVS.

Cardiovascular magnetic resonance pulmonary perfusion for guidance of interventional treatment of pulmonary vein stenosis

BACKGROUND

Pulmonary vein (PV) stenosis represents a rare but serious complication following radiofrequency ablation of atrial fibrillation with a comprehensive diagnosis including morphological stenosis grading together with the assessment of its functional consequences being imperative within the relatively narrow window for therapeutic intervention. The present study determined the clinical utility of a combined, single-session cardiovascular magnetic resonance (CMR) imaging protocol integrating pulmonary perfusion and PV angiographic assessment for pre-procedural planning and follow-up of patients referred for interventional PV stenosis treatment.

METHODS

CMR examinations (cine imaging, dynamic pulmonary perfusion, three-dimensional PV angiography) were performed in 32 consecutive patients prior to interventional treatment of PV stenosis and at 1-day and 3-months follow-up. Degree of PV stenosis was visually determined on CMR angiography; visual and quantitative analysis of pulmonary perfusion imaging was done for all five lung lobes.

RESULTS

Interventional treatment of PV stenosis achieved an acute procedural success rate of 90%. Agreement between visually evaluated pulmonary perfusion imaging and the presence or absence of a ≥ 70% PV stenosis was nearly perfect (Cohen's kappa, 0.96). ROC analysis demonstrated high discriminatory power of quantitative pulmonary perfusion measurements for the detection of ≥ 70% PV stenosis (AUC for time-to-peak enhancement, 0.96; wash-in rate, 0.93; maximum enhancement, 0.90). Quantitative pulmonary perfusion analysis proved a very large treatment effect attributable to successful PV revascularization already after 1 day.

CONCLUSION

Integration of CMR pulmonary perfusion imaging into the clinical work-up of patients with PV stenosis allowed for efficient peri-procedural stratification and follow-up evaluation of revascularization success.

Radiologic review of acquired pulmonary vein stenosis in adults

Acquired pulmonary vein stenosis (PVS) is an uncommon occurrence in adults, but one that carries significant morbidity/mortality. PVS can be secondary to neoplastic infiltration/extrinsic compression, non-neoplastic infiltration/extrinsic compression, or iatrogenic intervention. This article: (I) reviews the common causes of acquired PVS; (II) illustrates direct and indirect cross-sectional imaging findings in acquired PVS (in order to avoid misinterpretation of these imaging findings); and (III) details the role of imaging before and after the treatment of acquired PVS.

Non-interventional Management of Symptomatic Pulmonary Vein Occlusion after Radiofrequency Ablation for Atrial Fibrillation

Pulmonary vein occlusion (PVO) after atrial fibrillation ablation is often highly symptomatic. In cases with a clear target, balloon angioplasty and stenting can be successful. In the absence of such a target, surgical lobectomy has been reported as a treatment option, but the natural history of physiological adaptation may outweigh the risks of invasive therapies and a non-invasive strategy is valid in these situations. We present a case of highly symptomatic PVO managed non-invasively, with complete symptom resolution and return to high-intensity exercise. Catheter intervention may not always be possible in the absence of a target vessel, and lobectomy may not be necessary to manage PVO.