Losartan ameliorates “upstream” pulmonary vein vasculopathy in a piglet model of pulmonary vein stenosis

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.

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.

Rodent Models of Dilated Cardiomyopathy and Heart Failure for Translational Investigations and Therapeutic Discovery

Even with modern therapy, patients with heart failure only have a 50% five-year survival rate. To improve the development of new therapeutic strategies, preclinical models of disease are needed to properly emulate the human condition. Determining the most appropriate model represents the first key step for reliable and translatable experimental research. Rodent models of heart failure provide a strategic compromise between human in vivo similarity and the ability to perform a larger number of experiments and explore many therapeutic candidates. We herein review the currently available rodent models of heart failure, summarizing their physiopathological basis, the timeline of the development of ventricular failure, and their specific clinical features. In order to facilitate the future planning of investigations in the field of heart failure, a detailed overview of the advantages and possible drawbacks of each model is provided.

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.

Pulmonary Vein Stenosis Associated with Germline PIK3CA Mutation

Pulmonary vein stenosis is a rare and frequently lethal childhood disease. There are few known genetic associations, and the pathophysiology is not well known. Current treatments include surgery, interventional cardiac catheterization, and more recently, medications targeting cell proliferation, which are not uniformly effective. We present a patient with PVS and a PIK3CA mutation, who demonstrated a good response to the targeted inhibitor, alpelisib.

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

OBJECTIVE

The study objective was to evaluate outcomes of pulmonary vein stenosis repair in a large single-center cohort.

METHODS

Clinical data from a pulmonary vein stenosis registry were retrospectively reviewed identifying patients who underwent pulmonary vein stenosis repair. The primary/index operation was defined as the patient's first pulmonary vein stenosis operation during the study period.

RESULTS

Between January 2007 and August 2019, 174 patients underwent pulmonary vein stenosis repair. Bilateral pulmonary vein stenosis occurred in 111 patients (64%); 71 patients (41%) had 4-vessel disease. Fifty-nine patients (34%) had primary pulmonary vein stenosis. Median age was 9 months (interquartile range, 5-27) and weight was 6.5 kg (4.7-10.2). Surgical techniques evolved and included ostial resection, unroofing, reimplantation, sutureless, modified sutureless, and a newer anatomically focused approach of pulmonary vein stenosis resection with lateralization or patch enlargement of the pulmonary vein-left atrium connection. Twenty-three patients (13%) required reoperation. Cumulative 2-year incidence of postoperative transcatheter intervention (balloon dilation ± stenting) was 64%. One-, 2-, and 5-year survivals were 71.2%, 66.8%, and 60.6%, respectively. There was no association between surgery type and reoperation rate (hazard ratio, 2.38, P = .25) or transcatheter intervention (hazard ratio, 0.97, P = .95). The anatomically focused repair was associated with decreased mortality on univariate (hazard ratio, 0.38, P = .042) and multivariable analyses (hazard ratio, 0.19, P = .014). Antiproliferative chemotherapy was also associated with decreased mortality (hazard ratio, 0.47, P = .026).

CONCLUSIONS

This large single-center surgical pulmonary vein stenosis experience demonstrates encouraging midterm results. A new anatomically focused repair strategy aims to alleviate pulmonary vein angulation to minimize turbulence and shows promising early outcomes. Continued follow-up is required to understand longer-term outcomes for this surgical approach.

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.

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.

Selected 2020 Highlights in Congenital Cardiac Anesthesia

This article is a review of the highlights of pertinent literature published during the 12 months of 2020 that are of interest to the congenital cardiac anesthesiologist. After a search of the US National Library of Medicine's PubMed database, several topics emerged for which significant contributions were made in 2020. The authors of the present article considered the following topics noteworthy to be included in this review: pediatric cardiac care in the coronavirus disease 2019 era, the use of mechanical circulatory support in coronavirus disease 2019-related multisystem inflammatory syndrome in children, transfusion and coagulation management in children undergoing congenital heart surgery, and pulmonary vein stenosis.

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.

The many faces and outcomes of pulmonary vein stenosis in early childhood

Pulmonary vein stenosis is a rare and poorly understood condition causing obstruction of the large pulmonary veins and of blood flow from the lungs to the left atrium. This results in elevated pulmonary venous pressure and pulmonary edema, pulmonary hypertension, potentially cardiac failure, and death. Clinical signs of the disease include failure to thrive, increasingly severe dyspnea, hemoptysis, respiratory difficulty, recurrent respiratory tract infections/pneumonia, cyanosis, and subcostal retractions. On chest radiograph, the most frequent finding is increased interstitial, ground-glass and/or reticular opacity. Transthoracic echocardiography with pulsed Doppler delineates the stenosis, magnetic resonance imaging and multislice computerized tomography are used for further evaluation. Interventional cardiac catherization, surgical techniques, and medical therapies have been used with varying success as treatment options.

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.

Effect of Oral Losartan on Orthobiologics: Implications for Platelet-Rich Plasma and Bone Marrow Concentrate-A Rabbit Study

Recent efforts have focused on customizing orthobiologics, such as platelet-rich plasma (PRP) and bone marrow concentrate (BMC), to improve tissue repair. We hypothesized that oral losartan (a TGF-β1 blocker with anti-fibrotic properties) could decrease TGF-β1 levels in leukocyte-poor PRP (LP-PRP) and fibrocytes in BMC. Ten rabbits were randomized into two groups (N = 5/group): osteochondral defect + microfracture (control, group 1) and osteochondral defect + microfracture + losartan (losartan, group 2). For group 2, a dose of 10mg/kg/day of losartan was administrated orally for 12 weeks post-operatively. After 12 weeks, whole blood (WB) and bone marrow aspirate (BMA) samples were collected to process LP-PRP and BMC. TGF-β1 concentrations were measured in WB and LP-PRP with multiplex immunoassay. BMC cell populations were analyzed by flow cytometry with CD31, CD44, CD45, CD34, CD146 and CD90 antibodies. There was no significant difference in TGF-β1 levels between the losartan and control group in WB or LP-PRP. In BMC, the percentage of CD31+ cells (endothelial cells) in the losartan group was significantly higher than the control group (p = 0.008), while the percentage of CD45+ cells (hematopoietic cells-fibrocytes) in the losartan group was significantly lower than the control group (p = 0.03).

Single-institution outcomes of surgical repair of infracardiac total anomalous pulmonary venous connection

OBJECTIVE

This contemporary study sought to describe the outcomes of patients undergoing biventricular repair of infracardiac total anomalous pulmonary venous connection.

METHODS

A retrospective study was performed on patients with infracardiac total anomalous pulmonary venous connection who underwent sutureless technique or conventional repair between 2006 and 2018. Risk factors for survival and post-repair pulmonary vein stenosis (PVS) were assessed with Cox regression model. Time-to-event analysis was conducted using Kaplan-Meier estimates.

RESULTS

This study included 82 consecutive patients with the median age of 21 days (interquartile range, 9-40 days). The median follow-up was 29 months (interquartile range, 12.5-59 months) and was available in 95% of the survivors at the end of the study period in 2019. Overall, 8 deaths (8.5%) occurred in the conventional repair group. There was a trend of higher mortality in the conventional repair group, although it did not reach a statistical difference (P = .2). Postrepair PVS occurred at a median of 2 months (interquartile range, 1.2-3.6 months) postoperatively and all occurred in the conventional repair group. Time-to-event analysis with the event of postrepair PVS showed significantly higher freedom from restenosis in the sutureless technique group (P = .0004). Adjusted hazard ratios from time-dependent Cox model described the association between postrepair PVS and pulmonary venous confluence of antler configuration (hazard ratio, 2.14; 95% confidence interval, 1.03-5.47; P = .002) and the use of sutureless technique (hazard ratio, 0.72; 95% confidence interval, 0.39-0.97; P = .003).

CONCLUSIONS

Sutureless technique is associated with a lower risk of postrepair PVS in patients with infracardiac total anomalous pulmonary venous connection. pulmonary venous confluence configuration of antler appearance appears to be associated with restenosis and mortality.

Progression of vascular remodeling in pulmonary vein obstruction

OBJECTIVES

Pulmonary vein obstruction (PVO) frequently occurs after repair of total anomalous pulmonary vein connection with progression of intimal hyperplasia from the anastomotic site toward upstream pulmonary veins (PVs). However, the understanding of mechanism in PVO progression is constrained by lack of data derived from a physiological model of the disease, and no prophylaxis has been established. We developed a new PVO animal model, investigated the mechanisms of PVO progression, and examined a new prophylactic strategy.

METHODS

We developed a chronic PVO model using infant domestic pigs by cutting and resuturing the left lower PV followed by weekly hemodynamic parameter measurement and angiographic assessment of the anastomosed PV. Subsequently, we tested a novel therapeutic strategy with external application of rapamycin-eluting film to the anastomotic site.

RESULTS

We found the pig PVO model mimicked human PVO hemodynamically and histopathologically. This model exhibited increased expression levels of Ki-67 and phospho-mammalian target of rapamycin in smooth muscle-like cells at the anastomotic neointima. In addition, contractile to synthetic phenotypic transition; that is, dedifferentiation of smooth muscle cells and mammalian target of rapamycin pathway activation in the neointima of upstream PVs were observed. Rapamycin-eluting films externally applied around the anastomotic site inhibited the activation of mammalian target of rapamycin in the smooth muscle-like cells of neointima, and delayed PV anastomotic stenosis.

CONCLUSIONS

We demonstrate the evidence on dedifferentiation of smooth muscle-like cells and mammalian target of rapamycin pathway activation in the pathogenesis of PVO progression. Delivery of rapamycin to the anastomotic site from the external side delayed PV anastomotic stenosis, implicating a new therapeutic strategy to prevent PVO progression.

Medical treatment of a symptomatic acute pulmonary vein stenosis following antral pulmonary vein isolation

Pulmonary vein (PV) stenosis is a rare but serious complication of PV isolation. It usually develops 3-6 months after the procedure, but may rarely develop in the acute phase. We present a case of symptomatic PV stenosis within 48 hours after antral PV isolation. Following the initiation of medical treatment including a glucocorticoid, acute changes in the PV wall regressed and the patient's complaint of dyspnea at rest improved rapidly. In addition, long-term renin-angiotensin-aldosterone system (RAAS) blockers were given. The complaint did not recur during follow-up and PV stenosis was mild at 6 months.

Losartan-chitosan/dextran sulfate microplex as a carrier to lung therapeutics: Dry powder inhalation, aerodynamic profile and pulmonary tolerability

This study aims to obtain an inhalation powder with meaningful aerodynamic and safety profiles for the lung delivery of losartan (LS). For this, the capacity of self-assembly of chitosan (CS) and dextran sulfate (DS) to form CS/DS microplex (MC), incorporating high payload of hydrophilic LS was harnessed. Dry powder inhaler (LS-MC-DPI), prepared via spray drying of the best achieved LS-MC, was proposed to impart precise engineered inhalation characteristics. Micrometric robust CS/DS MC was revealed to offer the opportunity to heighten LS encapsulation, accounting for ~75%. LS-MC-DPI was successfully developed with high yield, flowability, respirable aerodynamic size and morphology which formed swellable and mucoadhesive network, facilitating intra-pulmonary delivery. Moreover, sustained release pattern, augmented deep lung deposition and safe histological profile were realized. Overall, the newly developed LS-MC DPI shows promises as an inhalation system. The aerodynamic performance and safety of LS-MC-DPI verify its suitability for further in vivo lung therapeutics.

Pulmonary Vein Stenosis in Infants: A Systematic Review, Meta-Analysis, and Meta-Regression

OBJECTIVE

To quantify outcomes of infants (<1 year of age) diagnosed with pulmonary vein stenosis (PVS).

STUDY DESIGN

MEDLINE (PubMed), Scopus, and Web of Science were searched through February 1, 2017, with no language restrictions. Publications including infants diagnosed with primary PVS, defined as the absence of preceding intervention(s), were considered. The study was performed according to Meta-analysis of Observational Studies in Epidemiology guidelines, the Systematic Reviews, and Meta-Analysis checklist, and registered prospectively. The quality of selected reports was critically examined. Data extraction was independently performed by multiple observers with outcomes agreed upon a priori. Data were pooled using an inverse variance heterogeneity model with incidence of mortality the primary outcome of interest.

RESULTS

Forty-eight studies of 185 infants were included. Studies were highly diverse with regards to the participants, interventions, and outcomes reported. The median (range) age at diagnosis was 5.0 (0.1-11.6) months. Pooled mortality was 58.5% (95% CI 49.8%-67.0%, I² = 21.4%). We observed greater mortality incidence among infants with 3 or 4 vein stenoses than in those with 1 or 2 vein stenoses (83.3% vs 36.1%; P < .01). We observed greater mortality among infants with bilateral than unilateral disease (78.7% vs 26.0%; P < .01).

CONCLUSIONS

Studies of primary PVS during infancy are highly variable in their methodological quality and estimates of clinical outcomes; therefore, estimates of prognosis remain uncertain. Multicenter, interdisciplinary collaborations, including alignment of key outcome measurements, are needed to answer questions beyond the scope of available data.

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

Results of acute pulmonary vasodilator testing (AVT) and the outcome of medical therapy have not been described in patients with segmental pulmonary vascular disease (SPVD). We sought to compare the pulmonary vasodilatory effects of oxygen, oxygen with nitric oxide, and diltiazem, and to describe the clinical course of patients with SPVD and pulmonary hypertension. A retrospective review of 16 patients with pulmonary hypertension and SPVD involving 2-3 major lung segments who underwent AVT between January 2000 and December 2015 was performed. Baseline hemodynamic measurements were obtained with patients breathing ≤ 30% oxygen. AVT was performed using 100% oxygen, 100% oxygen with 20 ppm nitric oxide, 21-35% oxygen, and 21-35% oxygen with intravenous diltiazem. The events associated with their long-term care were described. Nine of 16 patients were acutely responsive during AVT using the Sitbon criteria. The change in mean pulmonary artery pressure with oxygen or oxygen with nitric oxide (19 ± 12 mmHg) was significantly greater than the change with diltiazem (7 ± 5 mmHg). Pulmonary vasodilator therapy was initiated or escalated after AVT in 12 patients. Five patients subsequently experienced a decrease in mean pulmonary artery pressure or normalization in B-type natriuretic peptide. Three patients experienced adverse events associated with therapy. The actuarial survival was 94% over a period of 1-20 years. This study suggests that AVT can be used to identify patients with SPVD who are reactive to oxygen, oxygen with nitric oxide, and diltiazem. Clinical improvement was temporally associated with pulmonary vasodilator therapy in some patients with few adverse effects.

Pulmonary vein stenosis in patients with Smith-Lemli-Opitz syndrome

OBJECTIVE

To describe a group of children with co-incident pulmonary vein stenosis and Smith-Lemli-Opitz syndrome and to generate hypotheses as to the shared pathogenesis of these disorders.

DESIGN

Retrospective case series.

PATIENTS

Five subjects in a pulmonary vein stenosis cohort of 170 subjects were diagnosed with Smith-Lemli-Opitz syndrome soon after birth.

RESULTS

All five cases were diagnosed with Smith-Lemli-Opitz syndrome within 6 weeks of life, with no family history of either disorder. All cases had pathologically elevated 7-dehydrocholesterol levels and two of the five cases had previously reported pathogenic 7-dehydrocholesterol reductase mutations. Smith-Lemli-Opitz syndrome severity scores ranged from mild to classical (2-7). Gestational age at birth ranged from 35 to 39 weeks. Four of the cases were male by karyotype. Pulmonary vein stenosis was diagnosed in all cases within 2 months of life, earlier than most published cohorts. All cases progressed to bilateral disease and three cases developed atresia of at least one vein. Despite catheter and surgical interventions, all subjects' pulmonary vein stenosis rapidly recurred and progressed. Three of the subjects died, at 2 months, 3 months, and 11 months. Survival at 16 months after diagnosis was 43%.

CONCLUSIONS

Patients with pulmonary vein stenosis who have a suggestive syndromic presentation should be screened for Smith-Lemli-Opitz syndrome with easily obtainable serum sterol tests. Echocardiograms should be obtained in all newly diagnosed patients with Smith-Lemli-Opitz syndrome, with a low threshold for repeating the study if new respiratory symptoms of uncertain etiology arise. Further studies into the pathophysiology of pulmonary vein stenosis should consider the role of cholesterol-based signaling pathways in the promotion of intimal proliferation.

Pulmonary Vein Stenosis in a Newborn: A Commonly Overlooked Diagnosis

The diagnosis of primary pulmonary vein stenosis is often overlooked because its symptoms overlap lung diseases and pulmonary arterial hypertension. Its diagnosis may be difficult because the condition is progressive and associated with other defects. We present a case of pulmonary vein stenosis in a newborn with stenosis of the left-sided common pulmonary vein, diffuse hypoplasia of the superior right pulmonary vein, and atresia of the inferior right pulmonary vein.

The Year in Review

Congenital cardiac anesthesiology is a rapidly expanding field at both ends of the life spectrum. The care of the unborn child with congenital heart disease is becoming highly specialized in regional centers that offer advanced imaging techniques, coordinated specialist care, and potentially fetal interventions. As more children with congenital heart disease survive to adulthood, patients and their health care providers are facing new challenges. The growing volume of publications reflects this expanding field of congenital cardiac anesthesiology. This year in review article highlights some developing trends in the literature.