Pulmonary vein stenosis: Anatomic considerations, surgical management, and outcomes

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.

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.

Surgical repair of neonatal total anomalous pulmonary venous connection: A single institutional experience with 241 cases

Objective

Challenges persist in surgery for neonatal total anomalous pulmonary venous connection (neoTAPVC), with the high mortality risk not mitigated over time.

Methods

A prospectively collected single-center database containing all neonates with TAPVC undergoing biventricular repair in 2012 to 2020 was retrospectively reviewed. The primary outcome was death or postoperative pulmonary venous obstruction (PPVO). Based on the preoperative admission location in our hospital, patients were classified into those being admitted to cardiac intensive care unit versus neonatal intensive care unit or general pediatric intensive care unit. Access to dedicated presurgical care (DPC) was defined as patients who were preoperatively admitted to the cardiac intensive care unit.

Results

Overall, 241 patients with a median age at surgery of 14 days (interquartile range [IQR], 9-21 days) were included. Anomalous return was supracardiac in 38.6%, cardiac in 26.1%, infracardiac in 28.6%, and mixed in 6.6%. Patients receiving DPC had better survival (96.3% vs 84.3%; P = .0028) and lower incidence of PPVO (15.2% vs 28.6%; P = .011) compared with those without DPC. Patients in the DPC group were less likely to undergo operation within 24 hours on presentation (27.1% vs 40.3%; P = .041), had improved lactate clearance (1.5 [IQR, 1.0-2.2] vs 2.8 [IQR, 1.8-4.1]; P < .001), and had lower incidence of postoperative pulmonary hypertension crisis (2.8% vs 18.7%; P < .001) compared with those in no-DPC group. After matching, no difference in PPVO could be observed in patients undergoing conventional versus sutureless repair (22.6% vs 12.9%; P = .29).

Conclusions

Access to DPC potentially improves outcomes in the neoTAPVC setting; freedom from PPVO were similar using conventional versus sutureless repair.

Pulmonary vein stenosis in heart transplant patients

BACKGROUND

Pulmonary vein stenosis (PVS) is a rare pediatric condition associated with significant mortality and morbidity. PVS in patients following heart transplant (HT) has not yet been described.

METHODS

Patients who had clinically significant PVS following a heart transplant during the time period of April 1, 2013 to April 30, 2023, at Seattle Children's Hospital were identified. Clinically significant PVS was defined as an atretic vein or a vein with a gradient of ≥4 mmHg across at least one vein by echocardiogram or during cardiac catheterization. Patients who had a diagnosis of PVS prior to their transplant were excluded. A total of six patients were identified. We collected clinical data on these patients from their pre-transplant course to their most recent status.

RESULTS

The median age at HT was 7.5 months (range 2-13 months). The median time from HT to diagnosis of PVS was 3.5 months (range 0.3-13 months). At the last follow-up, the patients had had two to five pulmonary vein interventions, and there were no mortalities. The donor-to-recipient weight and total cardiac volume (TCV) ratios were less than 2.0 in five of six of the patients.

CONCLUSIONS

PVS is a rare complication that is associated with patients who undergo HT during infancy. PVS develops soon after HT and screening should occur accordingly. Interestingly, high donor-to-recipient weight and TCV ratios are not necessarily associated with the development of PVS. Further work will need to be performed in order to determine the significance of PVS in post-HT patients.

Multi-omics signatures in new-onset diabetes predict metabolic response to dietary inulin: findings from an observational study followed by an interventional trial

AIM

The metabolic performance of the gut microbiota contributes to the onset of type 2 diabetes. However, targeted dietary interventions are limited by the highly variable inter-individual response. We hypothesized (1) that the composition of the complex gut microbiome and metabolome (MIME) differ across metabolic spectra (lean-obese-diabetes); (2) that specific MIME patterns could explain the differential responses to dietary inulin; and (3) that the response can be predicted based on baseline MIME signature and clinical characteristics.

METHOD

Forty-nine patients with newly diagnosed pre/diabetes (DM), 66 metabolically healthy overweight/obese (OB), and 32 healthy lean (LH) volunteers were compared in a cross-sectional case-control study integrating clinical variables, dietary intake, gut microbiome, and fecal/serum metabolomes (16 S rRNA sequencing, metabolomics profiling). Subsequently, 27 DM were recruited for a predictive study: 3 months of dietary inulin (10 g/day) intervention.

RESULTS

MIME composition was different between groups. While the DM and LH groups represented opposite poles of the abundance spectrum, OB was closer to DM. Inulin supplementation was associated with an overall improvement in glycemic indices, though the response was very variable, with a shift in microbiome composition toward a more favorable profile and increased serum butyric and propionic acid concentrations. The improved glycemic outcomes of inulin treatment were dependent on better baseline glycemic status and variables related to the gut microbiota, including the abundance of certain bacterial taxa (i.e., Blautia, Eubacterium halii group, Lachnoclostridium, Ruminiclostridium, Dialister, or Phascolarctobacterium), serum concentrations of branched-chain amino acid derivatives and asparagine, and fecal concentrations of indole and several other volatile organic compounds.

CONCLUSION

We demonstrated that obesity is a stronger determinant of different MIME patterns than impaired glucose metabolism. The large inter-individual variability in the metabolic effects of dietary inulin was explained by differences in baseline glycemic status and MIME signatures. These could be further validated to personalize nutritional interventions in patients with newly diagnosed diabetes.

Predictors of Serious Adverse Events and High-Level Cardiorespiratory Support in Patients Undergoing Transcatheter Pulmonary Vein Interventions

Patients with pulmonary vein stenosis (PVS) often require frequent transcatheter pulmonary vein (PV) interventions for management of restenosis. Predictors of serious adverse events (AEs) and need for high-level cardiorespiratory support (mechanical ventilation, vasoactive support, and/or extracorporeal membrane oxygenation) 48 h after transcatheter PV interventions have not been reported. This is a single-center retrospective cohort analysis of patients with PVS who underwent transcatheter PV interventions from 3/1/2014 to 12/31/2021. Univariate and multivariable analyses were performed using generalized estimating equations to account for within-patient correlation. 240 patients underwent 841 catheterizations involving PV interventions (median 2 catheterizations per patient [1,3]). At least one serious AE was reported in 100 (12%) cases, the most common of which were pulmonary hemorrhage (n = 20) and arrhythmia (n = 17). There were 14 severe/catastrophic AEs (1.7% of cases) including three strokes and one patient death. On multivariable analysis, age less than 6 months, low systemic arterial saturation (< 95% in patients with biventricular [BiV] physiology, < 78% in single ventricle [SV] physiology), and severely elevated mean PA pressure (≥ 45 mmHg in BiV, ≥ 17 mmHg in SV) were associated with SAEs. Age less than 1 year, hospitalization prior to catheterization, and moderate-severe RV dysfunction were associated with high-level support after catheterization. Serious AEs during transcatheter PV interventions in patients with PVS are common, although major events such as stroke or death are uncommon. Younger patients and those with abnormal hemodynamics are more likely to experience serious AEs and require high-level cardiorespiratory support after catheterization.

Pulmonary Venous Gradients in Healthy Controls and Following the Repair of Total Anomalous Pulmonary Venous Return

The percent of children who can achieve a normal and physiologic pulmonary venous gradient and flow following the repair of Total Anomalous Pulmonary Venous Return (TAPVR) is not known. Pulmonary venous confluence gradients from infants with supra-, infra-, or mixed TAPVR, repaired using a direct anastomotic connection were measured. Data from age, weight, and gender-matched controls established the normal pulmonary venous gradient range (0.30-0.94 mmHg). TAPVR subjects were divided into three groups: (I) pulmonary venous gradient < 2 × normal with multiphasic flow (II) pulmonary venous gradient > 2 × normal with multiphasic flow, and (III) pulmonary venous gradient > 2 × normal with monophasic flow. From 63 children following TAPVR repair and 63 matched controls, pulmonary venous gradients were significantly lower [0.5 mmHg (IQR:0.4, 0.6) vs 1.6 mmHg (IQR:1.0, 2.4); p < 0.001], and multiphasic flow more frequent (100 vs. 84.1%; p = 0.001) within the control group. There were 38 children (60.3%) in group I, 15 (23.8%) in group II, and 10 (15.8%) in group III. Children in Group I were significantly older at the time of repair, had shorter cardiopulmonary bypass times, and did not utilize deep hypothermic circulatory arrest (DHCA). Multivariate analysis confirmed that avoiding DHCA [Odds Ratio 0.931 (0.913,0.994; p = 0.002)] and shorter cardiopulmonary bypass times [Odds Ratio 0.962 (0.861,0.968; p = 0.02)] during repair were associated with the lowest pulmonary venous gradients and multiphasic flow. Following TAPVR repair with a direct anastomosis, the majority of children can achieve a gradient two times normal or less with multiphasic pulmonary venous flow.