Progression of vascular remodeling in pulmonary vein obstruction

De Novo and Progressive Pulmonary Vein Stenosis Following Pediatric Heart Transplantation: A Multicenter Retrospective Study

BACKGROUND

Pulmonary vein stenosis (PVS) is a rare condition in which neointimal proliferation leads to venous and arterial hypertension. Little is known about PVS after heart transplant (HTx) in children. We sought to describe the characteristics and outcomes of children who develop PVS after HTx.

METHODS

We performed a retrospective review of patients ≤18 years old who underwent HTx at two HTx centers between April 2012 and October 2023. Patients with PVS were identified via database queries. Cardiac diagnosis, PVS location and extent, and outcomes were recorded.

RESULTS

Over 11.5 years, 422 patients underwent HTx across both centers. Nineteen patients with PVS (10 male) were identified, 15 with de novo PVS. Sixteen had underlying congenital heart disease (CHD), two with anomalous pulmonary venous return. PVS was diagnosed at a median of 2 months (range 2 weeks to 14 years) after HTx. At time of initial diagnosis, 13 patients had one-vessel PVS. At final follow-up, 7/19 (37%) had increases in the number of vessels involved. Six patients underwent surgery, and nine patients had stent or balloon angioplasty. Two patients were treated for pulmonary hypertension following PVS diagnosis. Three patients died from right heart failure secondary to PVS.

CONCLUSIONS

This is the largest study to describe the characteristics of post-HTx PVS in children. PVS occurs in 4.5% of HTx, and underlying CHD is a strong risk factor. Multiple vessels can be involved and may require catheter-based or surgical intervention. Clinicians must be vigilant in monitoring the development of PVS in this population.

Efficacy of Drug-Coated Balloon Angioplasty in Pulmonary Vein Stenosis or Total Occlusion

BACKGROUND

Current therapies for pulmonary vein stenosis (PVS) or pulmonary vein total occlusion (PVTO) involving angioplasty and stenting are hindered by high rates of restenosis.

OBJECTIVES

This study compares a novel approach of drug-coated balloon (DCB) angioplasty and stenting with the current standard of care in PVS or PVTO due to pulmonary vein isolation (PVI).

METHODS

A retrospective single-center study analyzed patients with PVS or PVTO due to PVI who underwent either angioplasty and stenting (NoDCB group; December 2012-December 2016) or DCB angioplasty and stenting (DCB group; January 2018-January 2021). Multivariable Andersen-Gill regression analysis assessed the risk of restenosis and target lesion revascularization (TLR).

RESULTS

The NoDCB group comprised 58 patients and 89 veins, with a longer median follow-up of 35 months, whereas the DCB group included 26 patients and 33 veins, with a median follow-up of 11 months. The DCB group exhibited more PVTO (NoDCB: 12.3%; DCB: 42.4%; P = 0.0001), with a smaller reference vessel size (NoDCB: 10.2 mm; DCB: 8.4 mm; P = 0.0004). Follow-up computed tomography was performed in 82% of NoDCB and 85% of DCB, revealing lower unadjusted rates of restenosis (NoDCB: 26%; DCB: 14.3%) and TLR (NoDCB: 34.2%; DCB: 10.7%) in the DCB group. DCB use was associated with a significantly lower risk of restenosis and TLR (HR: 0.003: CI: 0.00009-0.118; P = 0.002).

CONCLUSIONS

The novel approach of DCB angioplasty followed by stenting is effective and safe and significantly reduces the risk of restenosis and reintervention compared with the standard of care in PVS or PVTO due to PVI.

Targeted Rapamycin Delivery via Magnetic Nanoparticles to Address Stenosis in a 3D Bioprinted in Vitro Model of Pulmonary Veins

Vascular cell overgrowth and lumen size reduction in pulmonary vein stenosis (PVS) can result in elevated PV pressure, pulmonary hypertension, cardiac failure, and death. Administration of chemotherapies such as rapamycin have shown promise by inhibiting the vascular cell proliferation; yet clinical success is limited due to complications such as restenosis and off-target effects. The lack of in vitro models to recapitulate the complex pathophysiology of PVS has hindered the identification of disease mechanisms and therapies. This study integrated 3D bioprinting, functional nanoparticles, and perfusion bioreactors to develop a novel in vitro model of PVS. Bioprinted bifurcated PV constructs are seeded with endothelial cells (ECs) and perfused, demonstrating the formation of a uniform and viable endothelium. Computational modeling identified the bifurcation point at high risk of EC overgrowth. Application of an external magnetic field enabled targeting of the rapamycin-loaded superparamagnetic iron oxide nanoparticles at the bifurcation site, leading to a significant reduction in EC proliferation with no adverse side effects. These results establish a 3D bioprinted in vitro model to study PV homeostasis and diseases, offering the potential for increased throughput, tunability, and patient specificity, to test new or more effective therapies for PVS and other vascular diseases.

Interventions for Pulmonary Vein Stenosis

Pulmonary vein stenosis (PVS) is a rare and unique disease of infants and young children. PVS is attended by high morbidity and mortality, and for many decades, effective therapy eluded the practitioner. However, in the most recent era, interventional techniques when employed in combination with systemic (primary) therapy have had a remarkable impact on outcomes in these at-risk children. Despite apparent complete relief of PVS in a discrete region of a pulmonary vein, stenosis reliably recurs and progresses. In this review, we discuss the current state-of-the-art interventional techniques, through the lens of our collective experiences and practices.

Long-Term Outcomes of Surgical Repair of Supracardiac Total Anomalous Pulmonary Venous Connection

The conventional surgery (CS) of supracardiac total anomalous pulmonary venous connection (TAPVC) is not always effective particularly in the setting of complex anatomy such as the mixed variety of TAPVC. This study aimed to analyze the outcomes of surgical treatment of supracardiac TAPVC and determine the optimal strategy. From December 2009 to December 2023, patients with supracardiac TAPVC undergoing surgical repair in our institution were included. The Kaplan-Meier curve was used to demonstrate the survival estimates. The Cox proportional hazard model was used to identify risk factors for death and postoperative pulmonary venous obstruction (PVO). One hundred and eighty-three patients with supracardiac TAPVC underwent surgical repair [CS group, n = 102; modified L-shaped incision technique (MLIT) group, n = 81]. There were 8 in-hospital deaths and 16 late deaths. The survival rates at 1, 5, and 10 years were 89.0%, 85.0%, and 85.0%, respectively in the whole cohort. Multivariable analysis showed that lower weight (P = 0.031), prolonged CBP time (P = 0.007), preoperative PVO (P = 0.020), and emergency surgery (P = 0.001) were incremental risk factors for death, but using the MLIT was a protective factor for death (p = 0.028). In the CS group, patients with emergency operation had worse survival than patients with elective surgery (P < 0.001). However, in the MLIT group, patients with emergency operation had comparable survival to patients with elective surgery (P = 0.332). Postoperative PVO occurred in 30 patients. Fourteen patients underwent PVO-related reintervention. In the whole cohort, freedom from postoperative PVO at 1, 5, and 10 years were 87.5%, 80.6%, and 80.6%, respectively. Patients who underwent MLIT repair had a lower incidence of postoperative PVO (P < 0.001), and PVO-related reintervention (P = 0.019). Neonates(P = 0.033), aortic cross-clamp time (P = 0.012), preoperative PVO (P = 0.002), and using the CS (P = 0.005) were associated with postoperative PVO. In terms of postoperative PVO, MLIT had a protective effect compared with CS. In the CS group, Infant and Children patients had better freedom from postoperative PVO than Neonate patients (P < 0.001). However, in the MLIT group, Neonate patients had comparable freedom from postoperative PVO to Infant and Children patients (P = 0.332). The MLIT can achieve satisfactory outcomes for supracardiac TAPVC repair. Compared with CS, the MLIT was significantly associated with decreased death, postoperative PVO, and PVO-related reintervention. It is especially significant in improving the survival rate of patients undergoing emergency surgery and reducing the incidence of postoperative PVO in neonatal patients.

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.

A neonatal rat model of pulmonary vein stenosis

OBJECTIVES

Pulmonary vein stenosis (PVS), one of the most challenging clinical problems in congenital heart disease, leads to secondary pulmonary arterial hypertension (PAH) and right ventricular (RV) hypertrophy. Due to the lack of a rodent model, the mechanisms underlying PVS and its associated secondary effects are largely unknown, and treatments are minimally successful. This study developed a neonatal rat PVS model with the aim of increasing our understanding of the mechanisms and developing possible treatments for PVS.

METHODS

PVS was created at postnatal day 1 (P1) by banding pulmonary veins that receive blood from the right anterior and mid lobes. The condition was confirmed using echocardiography, computed tomography (CT), gross anatomic examination, hematoxylin and eosin (H&E) staining, fibrosis staining, and immunofluorescence. Lung and RV remodeling under the condition of PVS were evaluated using H&E staining, fibrosis staining, and immunofluorescence.

RESULTS

At P21, echocardiography revealed a change in wave form and a decrease in pulmonary artery acceleration time-indicators of PAH-at the transpulmonary valve site in the PVS group. CT at P21 showed a decrease in pulmonary vein diameter in the PVS group. At P30 in the PVS group, gross anatomic examination showed pulmonary congestion, H&E staining showed wall thickening and lumen narrowing in the upstream pulmonary veins, and immunofluorescence showed an increase in the smooth muscle layers in the upstream pulmonary veins. In addition, at P30 in the PVS group, lung remodeling was evidenced by hyperemia, thickening of pulmonary small vessel walls and smooth muscle layers, and reduction of the number of alveoli. RV remodeling was evidenced by an increase in RV free wall thickness.

CONCLUSIONS

A neonatal rat model of PVS was successfully established, showing secondary lung and RV remodeling. This model may serve as a useful platform for understanding the mechanisms and treatments for PVS.

Pulmonary Vein Stenosis-Balloon Angioplasty Versus Stenting: A Systematic Review and Meta-Analysis

Pulmonary vein stenosis (PVS) may arise from a variety of conditions and result in major morbidity and mortality. In some patients, pharmacologic therapy may help, but more often in advanced stages, mechanical treatment must be considered. Transcatheter approaches, both balloon angioplasty (BA) and stent implantation, have been applied. Although both are effective, they continue to be limited by restenosis. In this systematic review and meta-analysis, Ovid MEDLINE, Ovid Embase, Ovid Cochrane Central Register of Controlled Trials, Ovid Cochrane Database of Systematic Reviews, and Scopus were searched for English-language studies in humans published between January 1, 2010, and August 2, 2021. Two independent reviewers screened for studies in which BA or stenting was performed for PVS with reporting of restenosis outcomes, and data were independently extracted. A systematic review was performed, and overall restenosis rates were reported across all 34 included studies. Meta-analysis was then performed using RevMan version 5.4, assessing rates of restenosis and restenosis requiring reintervention. For restenosis rates, 4 studies treated in those studies with available data reported. For restenosis rates, 4 studies treated a total of 340 patients with 579 pulmonary vein interventions (225 with BA and 354 with stenting, mean follow-up 13-69 months). Restenosis requiring repeat intervention was reported in 3 studies, including 301 patients with 495 pulmonary vein interventions (157 with BA and 338 with stenting). Compared with BA, stenting was associated with both a lower risk for restenosis (risk ratio: 0.36; 95% CI: 0.18-0.73; P = 0.005) and a lower risk for restenosis requiring reintervention (RR: 0.36; 95% CI: 0.15-0.86; P = 0.02). For PVS intervention, restenosis and reintervention rates may be improved by stent implantation compared with BA.

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.

Application of sutureless technique in total anomalous pulmonary venous connection repair

The sutureless technique was initially used for the treatment of postoperative pulmonary vein obstruction (PVO) in patients with total anomalous pulmonary venous connection (TAPVC). However, as the effectiveness of the sutureless technique has been confirmed and widely developed, the sutureless technique has been used for the primary treatment of high-risk children with TAPVC who are at high risk of PVO. Compared with traditional surgery, the sutureless technique significantly reduces the incidence of postoperative PVO, re-intervention rate due to PVO, and postoperative mortality, but there are potential complications such as pericardial and confluent venous anastomosis, phrenic nerve damage, air embolism. In addition, the sutureless technique is not effective in dealing with the progressive stenosis of the pulmonary veins after sutureless surgery and diffuse stenosis of extrapulmonary proximal veins and intrapulmonary veins. These make the efficacy and safety of this procedure controversial. This paper reviews the research status of the sutureless technique in TAPVC repair at home and abroad over the years.

Transcatheter Recanalization of Atretic Pulmonary Veins in Infants and Children

BACKGROUND

Pulmonary vein stenosis is a progressive disease associated with a high rate of mortality in children. If left untreated, myofibroblastic proliferation can lead to pulmonary vein atresia (PVA). In our experience, transcatheter recanalization has emerged as a favorable interventional option. We sought to determine the acute success rate of recanalization of atretic pulmonary veins and mid-term outcomes of individual veins after recanalization.

METHODS

We reviewed all patients with PVA at our institution between 2008 and 2020 diagnosed by either catheterization or cardiac computed tomography. All veins with successful recanalization were reviewed and procedural success rate and patency rate were noted. Competing risk analysis was performed to demonstrate outcomes of individual atretic veins longitudinally.

RESULTS

Between 2008 and 2020, our institution diagnosed and treated 131 patients with pulmonary vein stenosis. Of these, 61 patients developed atresia of at least one pulmonary vein. In total, there were 97 atretic pulmonary veins within this group. Successful recanalization was accomplished in 47/97 (48.5%) atretic veins. No atretic pulmonary veins were successfully recanalized before 2012. The majority of veins were recanalized between 2017 and 2020-39/56 (70%). The most common intervention after recanalization was drug-eluting stent placement. At 2-year follow-up 42.6% of recanalized veins (20.6% of all atretic veins) remained patent with a median of 4 reinterventions per person.

CONCLUSIONS

Transcatheter recanalization of PVA can result in successful reestablishment of flow to affected pulmonary veins in many cases. Drug-eluting stent implantation was the most common intervention performed immediately post-recanalization. Vein patency was maintained in 42.6% of patients at 2-year follow-up from recanalization with appropriate surveillance and reintervention. Overall, only a small portion of atretic pulmonary veins underwent successful recanalization with maintained vessel patency at follow-up. Irrespective of successful recanalization, there was no detectable survival difference between the more recently treated PVA cohort and non-PVA cohort.

Progress in Pulmonary Vein Stenosis: Lessons from Success in Treating Pulmonary Arterial Hypertension

Pulmonary vein stenosis (PVS) is a rare and poorly understood condition that can be classified as primary, acquired, status-post surgical repair of PVS, and/or associated with developmental lung disease. Immunohistochemical studies demonstrate that obstruction of the large (extrapulmonary) pulmonary veins is associated with the neointimal proliferation of myofibroblasts. This rare disorder is likely multifactorial with a spectrum of pathobiology. Treatments have been historically surgical, with an increasing repetitive interventional approach. Understanding the biology of these disorders is in its infancy; thus, medical management has lagged behind. Throughout medical history, an increased understanding of the underlying biology of a disorder has led to significant improvements in care and outcomes. One example is the treatment of pulmonary arterial hypertension (PAH). PAH shares several common themes with PVS. These include the spectrum of disease and biological alterations, such as vascular remodeling and vasoconstriction. Over the past two decades, an exponential increase in the understanding of the pathobiology of PAH has led to a dramatic increase in medical therapies that have changed the landscape of the disease. We believe that a similar approach to PVS can generate novel medical therapeutic targets that will markedly improve the outcome of these vulnerable patients.

Prematurity and Pulmonary Vein Stenosis: The Role of Parenchymal Lung Disease and Pulmonary Vascular Disease

Pulmonary vein stenosis (PVS) has emerged as a critical problem in premature infants with persistent respiratory diseases, particularly bronchopulmonary dysplasia (BPD). As a parenchymal lung disease, BPD also influences vascular development with associated pulmonary hypertension recognized as an important comorbidity of both BPD and PVS. PVS is commonly detected later in infancy, suggesting additional postnatal factors that contribute to disease development, progression, and severity. The same processes that result in BPD, some of which are inflammatory-mediated, may also contribute to the postnatal development of PVS. Although both PVS and BPD are recognized as diseases of inflammation, the link between them is less well-described. In this review, we explore the relationship between parenchymal lung diseases, BPD, and PVS, with a specific focus on the epidemiology, clinical presentation, risk factors, and plausible biological mechanisms in premature infants. We offer an algorithm for early detection and prevention and provide suggestions for research priorities.

The Outcomes of Total Anomalous Pulmonary Venous Connection in Neonates-10-Year Experience at a Single Center

Background: Recent developments in surgical techniques and hospital care have led to improved outcomes following repair of total anomalous pulmonary venous connection (TAPVC). However, surgical repair of neonatal TAPVC remains associated with a high risk of postoperative mortality and pulmonary venous obstruction (PVO). We conducted this retrospective study to identify risk factors associated with surgical outcomes in the neonatal population.

Methods: A retrospective review was conducted for all 127 neonates who underwent operations for isolated TAPVC from January 2009 to January 2019.

Results: Preoperative PVO occurred in 33 (26.0%) of the 127 patients. Fifty patients (39.4%) required tracheal intubation before the operation. Twenty-three patients (18.1%) underwent emergency surgery. There were 11 (8.7%) early deaths. Significant risk factors were prolonged cardiopulmonary bypass (CPB) time (p = 0.013) and increased postoperative central venous pressure (CVP, p = 0.036). There were 5 (4.3%) late deaths within 1 year of repair. The risk factors for overall death were preoperative acidosis (p = 0.001), prolonged CPB time (p < 0.001) and increased postoperative CVP (p = 0.007). In particular, mortality was significantly higher (p = 0.007) with a postoperative CVP > 8 mmHg. With an increase in use of sutureless techniques (p = 0.001) and decrease in deep hypothermic circulatory arrest (p = 0.009) over the past 5 years, postoperative mortality greatly decreased (21.2%: 6.7%, p = 0.016). Postoperative PVO occurred in 15 patients (11.8%). Risk factors were mixed TAPVC (p = 0.037), preoperative acidosis (p = 0.001) and prolonged CPB time (p = 0.006).

Conclusion: Although postoperative mortality of neonatal TAPVC has dropped to 6.7% over the past 5 years, it is still relatively high. Risk factors for postoperative death include preoperative acidosis, prolonged CPB time and increased postoperative CVP. Mortality was significantly higher for neonates with an average CVP > 8 mmHg 24 h after surgery.

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.

Primary pulmonary vein stenosis during infancy: state of the art review

Primary pulmonary vein stenosis (PPVS) is an emerging problem among infants. In contrast to acquired disease, PPVS is the development of stenosis in the absence of preceding intervention. While optimal care approaches remain poorly characterized, over the past decade, understanding of potential pathophysiological mechanisms and development of novel therapeutic strategies are increasing. A multidisciplinary team of health care providers was assembled to review the available evidence and provide a common framework for the diagnosis, management, and treatment of PPVS during infancy. To address knowledge gaps, institutional and multi-institutional approaches must be employed to generate knowledge specific to ex-premature infants with PPVS. Within individual institutions, creation of a team comprised of dedicated health care providers from diverse backgrounds is critical to accelerate clinical learning and provide care for infants with PPVS. Multi-institutional collaborations, such as the PVS Network, provide the infrastructure and statistical power to advance knowledge for this rare disease.

Pulmonary Vein Stenosis: Incremental Knowledge Gains to Improve Outcomes

Pulmonary vein stenosis remains a considerable clinical challenge, with high mortality still present in children with progressive disease. In this review, we discuss the clinical spectrum of pulmonary vein stenosis and what is known about the etiology and potential modifying and contributing factors in progressive pulmonary vein stenosis.

Systemic Sirolimus Therapy for Infants and Children With Pulmonary Vein Stenosis

BACKGROUND

Anatomic interventions for pulmonary vein stenosis (PVS) in infants and children have been met with limited success. Sirolimus, a mammalian target of rapamycin inhibitor, has demonstrated promise as a primary medical therapy for PVS, but the impact on patient survival is unknown.

OBJECTIVES

The authors sought to investigate whether mTOR inhibition with sirolimus as a primary medical therapy would improve outcomes in high-risk infants and children with PVS.

METHODS

In this single-center study, patients with severe PVS were considered for systemic sirolimus therapy (SST) following a strict protocol while receiving standardized surveillance and anatomic therapies. The SST cohort was compared with a contemporary control group. The primary endpoint for this study was survival. The primary safety endpoint was adverse events (AEs) related to SST.

RESULTS

Between 2015 and 2020, our PVS program diagnosed and treated 67 patients with ≥moderate PVS. Of these, 15 patients were treated with sirolimus, whereas the remaining patients represent the control group. There was 100% survival in the SST group compared with 45% survival in the control group (log-rank p = 0.004). A sensitivity analysis was completed to address survival bias using median time from diagnosis of PVS to SST. A survival advantage persisted (log-rank p = 0.027). Two patients on sirolimus developed treatable AEs. Patients in the SST group underwent frequent transcatheter interventions with 3.7 catheterizations per person-year (25th to 75th percentile: 2.7 to 4.4 person-years). Median follow up time was 2.2 years (25th to 75th percentile: 1.2 to 2.9 years) in the SST group versus 0.9 years (25th to 75th percentile: 0.5 to 2.7 years) in the control group.

CONCLUSIONS

The authors found a survival benefit associated with SST in infants and children with moderate-to-severe PVS. This survival benefit persisted after adjusting the analysis for survival bias. There were 2 mild AEs associated with SST during the study period; both patients were able to resume therapy without recurrence.

Primary Pulmonary Vein Stenosis: A New Look at a Rare but Challenging Disease

Primary pulmonary vein stenosis (PPVS) represents a rare but emerging, often progressive heterogeneous disease with high morbidity and mortality in the pediatric population. Although our understanding of PPVS disease has improved markedly in recent years, much remains unknown regarding disease pathogenesis, distinct disease phenotypes, and patient- and disease-related risk factors driving the unrelenting disease progression characteristic of PPVS. In the pediatric population, risk factors identified in the development of PPVS include an underlying congenital heart disease, prematurity and associated conditions, and an underlying genetic or congenital syndrome. Continued improvement in the survival of high-risk populations, coupled with ongoing advances in general PPVS awareness and diagnostic imaging technologies suggest that PPVS will be an increasingly prevalent disease affecting pediatric populations in the years to come. However, significant challenges persist in both the diagnosis and management of PPVS. Standardized definitions and risk stratification for PPVS are lacking. Furthermore, evidence-based guidelines for screening, monitoring, and treatment remain to be established. Given these limitations, significant practice variation in management approaches has emerged across centers, and contemporary outcomes for patients affected by PPVS remain guarded. To improve care and outcomes for PPVS patients, the development and implementation of universal definitions for disease and severity, as well as evidence-based guidelines for screening, monitoring, cardiorespiratory care, and indications for surgical intervention will be critical. In addition, collaboration across institutions will be paramount in the creation of regionalized referral centers as well as a comprehensive patient registry for those requiring pulmonary vein stenosis.

The Real Need for Regenerative Medicine in the Future of Congenital Heart Disease Treatment

Bioabsorbable materials made from polymeric compounds have been used in many fields of regenerative medicine to promote tissue regeneration. These materials replace autologous tissue and, due to their growth potential, make excellent substitutes for cardiovascular applications in the treatment of congenital heart disease. However, there remains a sizable gap between their theoretical advantages and actual clinical application within pediatric cardiovascular surgery. This review will focus on four areas of regenerative medicine in which bioabsorbable materials have the potential to alleviate the burden where current treatment options have been unable to within the field of pediatric cardiovascular surgery. These four areas include tissue-engineered pulmonary valves, tissue-engineered patches, regenerative medicine options for treatment of pulmonary vein stenosis and tissue-engineered vascular grafts. We will discuss the research and development of biocompatible materials reported to date, the evaluation of materials in vitro, and the results of studies that have progressed to clinical trials.

Clinical Outcomes Predictors and Surgical Management of Primary Pulmonary Vein Stenosis

BACKGROUND

Surgical outcomes for primary pulmonary vein stenosis (PPVS) remain unfavorable, and risk factors are still poorly understood. The purpose of this study is to evaluate outcomes and risk factors after PPVS repair.

METHODS

Forty patients with PPVS undergoing surgical repair in Fuwai Hospital from 2010 to 2020 were included retrospectively. Adverse outcomes included mortality, pulmonary vein (PV) restenosis and reintervention. A univariate and multivariate risk analysis was performed to determine risk factors.

RESULTS

The mean follow-up duration was 37.5 ± 31.5 months. Sutureless technique was performed in 7 patients (17.5%), endovenectomy in 9 patients (22.5%), and patch venoplasty in 24 patients (60%). Bilateral PV involvement was documented in 12 patients (30%). Overall mortality, PV reintervention, and restenosis occurred in 15%, 12.5%, and 25% of patients, respectively. Freedom from overall mortality, PV reintervention, and restenosis at 5 years was 85%±6.3%, 88.9%±5.2%, and 65.1%±13.2%, respectively. Multivariate analysis revealed that bilateral PV involvement was an independent risk factor for mortality or PV reintervention (hazard ratio, 10.4; 95% confident interval, 1.9-56; p = 0.006), and involvement of left inferior PV was an independent risk factor for postoperative restenosis of left inferior PV (hazard ratio, 13.1; confident interval, 2.2-76.8; p = 0.004).

CONCLUSIONS

Surgical treatment for PPVS remains a challenging issue with imperfect prognosis. Therefore, it is right and appropriate to take close surveillance on mild or moderate stenosis on a single pulmonary vein. Bilateral and left inferior pulmonary vein involvement are independent risk factors for adverse outcomes.

Histopathology of anastomotic stenosis after total anomalous pulmonary vein connection

We report a case of a 10-month-old girl who was diagnosed with pulmonary vein stenosis after total anomalous pulmonary vein connection repair and underwent release of an anastomotic stenosis. Histopathological examinations of the resected anastomotic tissue revealed intimal hyperplasia at the anastomotic site. Predominant lesion cells were identified as myofibroblasts and had the characteristics of fibroblasts and synthetic smooth muscle cells. These cells could be a useful target for preventing anastomotic stenosis after total anomalous pulmonary vein connection repair.

Pulmonary Vein Stenosis: Moving From Past Pessimism to Future Optimism

Pulmonary Vein Stenosis (PVS) is a rare disease with a prevalence of around 1. 7 cases per 100,000 children under 2 years old. Treatment options for this disease have not provided great results and pathophysiology of this condition is still poorly understood. Here, we will review the history of PVS including diagnostic tools and treatments, the current management approach, and what the future holds for this devastating disease.