Outcomes After Stent Implantation for the Treatment of Congenital and Postoperative Pulmonary Vein Stenosis in Children

Pulmonary vein stenosis: future optimism

PURPOSE OF REVIEW

Pulmonary vein stenosis (PVS) is a rare disease with high morbidity and mortality. Prevention of restenosis remains challenging. This review will highlight recent advances in therapy that are beginning to show a survival benefit.

RECENT FINDINGS

Intervention for multivessel pediatric PVS may be surgical or transcatheter, both with high restenosis rates. At a threshold upstream diameter of 7 mm, the risk of restenosis decreases. Close vigilance and frequent reinterventions, typically transcatheter, are now accepted practice to maintain vein patency and achieve upstream growth. Suppressive agents targeting the exuberant myofibroblastic proliferation characteristic of PVS, specifically sirolimus, delivered locally on the surface of balloons and stents, and as adjunct systemic therapy, have been shown to increase survival and decrease reinterventions. Newer surgical techniques focused on shortening and straightening the vein to optimize flow dynamics, coupled with hybrid intraoperative stent placement in selected cases, also show a survival benefit.Adult-onset PVS, most commonly a complication of pulmonary vein isolation, now occurs rarely, and generally responds to transcatheter intervention. Further advances in ablation techniques aim to eliminate this complication.

SUMMARY

An aggressive approach of frequent reinterventions is a necessary strategy rather than treatment failure. More granular understanding of the mechanisms underlying PVS leading to novel muti-pronged anatomic and suppressive therapy are yielding improved survival.Multispecialty PVS teams at the institutional level and multiinstitutional collaboration, now possible via the PVS registry, are crucial to optimal care and future progress.

Balloon Dilation Technique Influences Stent Shortening and Intentional Stent Fracture During Overexpansion of Drug-Eluting Stents: A Bench-Testing Study

BACKGROUND AND AIMS

Drug-eluting stents (DES) are not designed for overexpansion to supra-nominal diameters or intentional stent fracture (ISF). The optimal dilation technique to minimize stent shortening (SS) and achieve ISF to accommodate pediatric somatic growth has not been described.

METHODS

Three sizes of two commonly used DES were implanted within a silicone model to simulate blood vessels. Each stent was serially dilated in 1 mm increments under fluoroscopy using three techniques: 2 cm length, semi-compliant balloons (Technique 1), 2 cm, noncompliant balloons straddling the entire stent (Technique 2), or noncompliant balloons in an "inside-out" manner (balloon shorter than stent or 2 cm balloon aligned with distal end of stent (no straddle); (Technique 3). Technique 1 crossed over to noncompliant balloons once stent "napkin-ringed" (NR). Percent SS = (Lnominal - Lfinal)/Lnominal * 100.

RESULTS

Technique 1 resulted in the greatest SS (median 85%, IQR 82, 87) and universal napkin ringing. Technique 2 caused less SS (median 14%, IQR 7, 15), and Technique 3 caused the least SS (median 7%, IQR 3, 11). ISF was achieved in all, however, the inside-out technique caused ISF at smaller stent diameters (median 114% recommended postdilation limit vs. 122%-131%) and lower inflation pressures (median 15 vs. 28-29 ATM). ISF was achieved in Technique 1 after napkin ringing but required larger noncompliant balloons than other techniques (median 8.5 vs. 7 mm).

CONCLUSION

Inside-out dilation resulted in less SS and fracture at smaller diameters with lower inflation pressures. This technique may improve the ISF success rate of DES in pediatric patients.

Modified Technique for Repairing Recurrent Pulmonary Venous Obstruction

Postoperative pulmonary venous obstruction after the repair of total anomalous pulmonary venous connection is a challenging complication, especially when it occurs in the upstream pulmonary vein outside the pericardial sac. Here, we report such a case that was resolved successfully by a novel, modified, sutureless technique that repositioned the pericardial reflection to expand the pericardial sac.

Postrepair Pulmonary Vein Stenosis: Addressing Anatomic and Patient Risk Factors to Improve Outcomes

Surgical results for correction of total anomalous pulmonary venous connection (TAPVC) have improved in the current era. Postrepair pulmonary vein stenosis (PR-PVS) remains a major complication following TAPVC repair, often necessitating multiple reinterventions, and impacting patient outcomes. Considerations for patient and anatomical risk factors, surgical techniques for primary TAPVC repair, as well PR-PVS postoperative surveillance and management will be reviewed. We will also touch on emerging areas of research related to PR-PVS pathogenesis and incorporation of patient-specific simulation for surgical planning in TAPVC.

Prognosis and Management of Recurrent Stenosis After Pulmonary Vein Stenting: A Prospective Study

BACKGROUND

Pulmonary vein stenting is effective for severe pulmonary vein stenosis, which is limited by restenosis. The assessment and management of in-stent restenosis (ISR) are inadequate, and follow-up outcomes after reintervention remain unknown.

OBJECTIVES

This study aimed to assess the prognosis and management of pulmonary vein ISR and determine whether the modified stent-in-stent strategy is superior to balloon angioplasty (BA) in treating ISR.

METHODS

The authors conducted a prospective observational study on patients with severe pulmonary vein stenosis post radiofrequency ablation for atrial fibrillation.

RESULTS

A total of 107 patients with 174 severely stenosed veins underwent successful stenting. Forty-three veins among 36 patients experienced ISR (24.7%, 43 of 174). Veins developing ISR had smaller diameter stents (7.8 ± 0.8 mm vs 9.2 ± 0.7 mm; P = 0.008). Restenosis veins were assigned to BA group or stent-in-stent group. Success rate was 95.7% for BA and 90.0% for stent-in-stent. Twelve veins experienced recurrent ISR, including 2 in stent-in-stent group (11.1%, 2 of 18) and 10 in BA group (45.5%, 10 of 22). The risk of recurrent stenosis was significantly lower in veins treated with the stent-in-stent method than with BA (HR: 0.21; 95% CI: 0.07-0.64; P = 0.02). Patients in the stent-in-stent group had greater exercise endurance and better World Health Organization cardiac functional class compared with BA group (F = 7.2; P < 0.05; and F = 4.4; P < 0.05, respectively) at 6- and 12-month follow-ups.

CONCLUSIONS

Our modified stent-in-stent implantation approach is superior to BA for treating pulmonary vein ISR, by reducing recurrent restenosis rate and improving exercise endurance.

Systemic Sirolimus Therapy Is Associated With Reduced Intervention Frequency in Pulmonary Vein Stenosis

Background

Early clinical outcomes data for adjunctive systemic sirolimus therapy (SST) for moderate to severe pediatric pulmonary vein stenosis (PVS) are promising but limited.

Objectives

The authors aimed to characterize a cohort of patients treated with SST to determine if SST was associated with a reduction in frequency of PVS interventions.

Methods

Medical records of 45 patients with PVS treated with SST for ≥1 month from 2015 to 2022 were retrospectively reviewed. PVS intervention rates pre-SST and on-SST were compared using generalized Poisson mixed models, accounting for paired intervals within each patient. In addition to an unadjusted model, an adjusted model accounted for age at interval start, PVS type, sex, prematurity, and concurrent antiproliferative therapy. Mean number of PVS interventions per patient over time (mean cumulative function) were also compared for these intervals in an unpaired fashion. Kaplan-Meier estimates were used to quantify survival over time.

Results

Median per-patient PVS intervention rate (interventions/year) was 5 pre-SST and 1.7 on-SST, significantly lower on-SST in the unadjusted and adjusted models (P < 0.001, both). Patients accrued an increased cumulative number of interventions over time pre-SST compared to on-SST by mean cumulative function (P < 0.001). Median duration of SST was 1.7 years and median follow-up time from SST initiation was 2.7 years. There were 6 mortalities at a median of 1.1 years (range, 4.4 months-6.5 years) following SST initiation.

Conclusions

SST was associated with a reduction in frequency of PVS interventions. Prospective studies are warranted to determine potential causality, delineate patient- and vein-level outcomes, and determine optimal therapeutic duration.

Hybrid Interventions for Pulmonary Vein Stenosis: Leveraging Intraoperative Endovascular Adjuncts in Challenging Clinical Scenarios

Background: Pediatric pulmonary vein stenosis (PVS) is often progressive and treatment-refractory, requiring multiple interventions. Hybrid pulmonary vein interventions (HPVIs), involving intraoperative balloon angioplasty or stent placement, leverage surgical access and customization to optimize patency while facilitating future transcatheter procedures. We review our experience with HPVI and explore potential applications of this collaborative approach. Methods: Retrospective chart review of all HPVI cases between 2009 to 2023. Results: Ten patients with primary (n = 5) or post-repair (n = 5) PVS underwent HPVI at median age of 12.7 months (range 6.6 months-9.5 years). Concurrent surgical PVS repair was performed in 7/10 cases. Hybrid pulmonary vein intervention was performed on 17 veins, 13 (76%) with prior surgical or transcatheter intervention(s). One patient underwent intraoperative balloon angioplasty of an existing stent. In total, 18 stents (9 bare metal [5-10 mm diameter], 9 drug eluting [3.5-5 mm diameter]) were placed in 16 veins. At first angiography (median 48 days [range 7 days-2.8 years] postoperatively), 8 of 16 (50%) HPVI-stented veins developed in-stent stenosis. Two patients died from progressive PVS early in the study, one prior to planned reintervention. Median time to first pulmonary vein reintervention was 86 days (10 days-2.8 years; 8/10 patients, 13/17 veins). At median survivor follow-up of 2.2 years (2.3 months-13.1 years), 1 of 11 surviving HPVI veins were completely occluded. Conclusions: Hybrid pulmonary vein intervention represents a viable adjunct to existing PVS therapies, with promising flexibility to address limitations of surgical and transcatheter modalities. Reintervention is anticipated, necessitating evaluation of long-term benefits and durability as utilization increases.

Incidence and predictors of in-stent restenosis following intervention for pulmonary vein stenosis due to fibrosing mediastinitis

BACKGROUND

Fibrosing mediastinitis (FM) is a rare yet fatal condition, caused by different triggers and frequently culminating in the obstruction of the pulmonary vasculature and airways, often leading to pulmonary hypertension and right heart failure. Percutaneous transluminal pulmonary venoplasty (PTPV) is an emerging treatment for pulmonary vein stenosis (PVS) caused by FM. Our previous study showed as high as 24% of in-stent restenosis (ISR) in FM. However, the predictors of ISR are elusive.

OBJECTIVES

We sought to identify the predictors of ISR in patients with PVS caused by extraluminal compression due to FM.

METHODS

We retrospectively enrolled patients with PVS-FM who underwent PTPV between July 1, 2018, and December 31, 2022. According to ISR status, patients were divided into two groups: the ISR group and the non-ISR group. Baseline characteristics (demographics and lesions) and procedure-related information were abstracted from patient records and analyzed. Univariate and multivariate analyses were performed to determine the predictors of ISR.

RESULTS

A total of 142 stents were implanted in 134 PVs of 65 patients with PVS-FM. Over a median follow-up of 6.6 (3.4-15.7) months, 61 of 134 PVs suffered from ISR. Multivariate analysis demonstrated a significantly lower risk of ISR in PVs with a larger reference vessel diameter (RVD) (odds ratio (OR): 0.79; 95% confidence interval [CI]: 0.64 to 0.98; P = 0.032), and stenosis of the corresponding pulmonary artery (Cor-PA) independently increased the risk of restenosis (OR: 3.41; 95% CI: 1.31 to 8.86; P = 0.012). The cumulative ISR was 6.3%, 21.4%, and 39.2% at the 3-, 6-, and 12-month follow-up, respectively.

CONCLUSION

ISR is very high in PVS-FM, which is independently associated with RVD and Cor-PA stenosis.

TRAIL REGISTRATION

Chinese Clinical Trials Register; No.: ChiCTR2000033153. URL: http://www.chictr.org.cn .

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.

Hybrid Interventions in Congenital Heart Disease: A Review of Current Practice and Rationale for Use

BACKGROUND

Hybrid interventions have become a common option in the management for a variety of patients with congenital heart disease. In this review, we discuss the data that have driven decision making about hybrid interventions to date.

METHODS

The existing literature on various hybrid approaches was reviewed and summarized. In addition, the key tenants to creating a successful hybrid program within a congenital heart center are elucidated.

RESULTS

Hybrid strategies for single-ventricle patients, pulmonary atresia with intact ventricular septum, branch pulmonary artery stenosis, and muscular ventricular septal defect closure have important benefits and limitations compared with traditional approaches.

CONCLUSION

A growing body of evidence supports the use of hybrid interventions in congenital heart disease. But important questions remain regarding improved survival and other long-term outcomes, such as neurocognition, that might impact widespread adoption as a primary treatment strategy.

Absorbable metal stents for vascular use in pediatric cardiology: progress and outlook

The past five years have yielded impressive advancements in fully absorbable metal stent technology. The desired ultimate ability for such devices to treat a vascular stenosis without long-term device-related complications or impeding future treatment continues to evoke excitement in clinicians and engineers alike. Nowhere is the need for fully absorbable metal stents greater than in patients experiencing vascular anomalies associated with congenital heart disease (CHD). Perhaps not surprisingly, commercially available absorbable metal stents have been implanted in pediatric cardiology patients with conditions ranging from pulmonary artery and vein stenosis to coarctation of the aorta and conduit/shunt reconstructions. Despite frequent short term procedural success, device performance has missed the mark with the commercially available devices not achieving degradation benchmarks for given applications. In this review we first provide a general overview detailing the theory of absorbable metal stents, and then review recent clinical use in CHD patients since the release of current-generation absorbable metal stents around 2019. We also discuss the challenges and our center's experience associated with the use of absorbable metal stents in this pediatric population. Lastly, we present potential directions for future engineering endeavors to mitigate existing challenges.

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.

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.

Replacement of pulmonary venous stent during Fontan operation

Post-operative pulmonary venous stenosis is a poor prognostic factor in single-ventricle haemodynamics. Implantation of a drug-eluting stent is a therapeutic option. However, due to their small size, they inevitably become inadequate as the patient grows. We present the first case, to the best of our knowledge, of the replacement of a small-diameter stent with a large-diameter stent during Fontan surgery.

Hybrid approach to pulmonary vein stenting after Fontan palliation

Pulmonary vein stenosis is poorly tolerated in patients who have undergone Fontan palliation and typically requires surgical or transcatheter intervention. Percutaneous transcatheter approaches to intervention can be technically difficult due to challenging anatomy. A hybrid per-atrial transcatheter approach for stenting pulmonary veins provides a direct approach to the pulmonary veins and has the potential to improve safety and efficacy of this complex intervention. We describe our experience with hybrid per-atrial pulmonary vein stenting in three patients with pulmonary vein stenosis following Fontan palliation.

A Risk Prediction Model for Reintervention After Total Anomalous Pulmonary Venous Connection Repair

BACKGROUND

Outcomes after total anomalous pulmonary venous connection (TAPVC) repair remain suboptimal due to recurrent pulmonary vein (PV) obstruction requiring reinterventions. We sought to develop a clinical prediction rule for PV reintervention after TAPVC repair.

METHODS

Data from consecutive patients who underwent TAPVC repair at a single institution from January 1980 to January 2020 were retrospectively reviewed after Institutional Review Board approval. The primary outcome was postdischarge (late) unplanned PV surgical or transcatheter reintervention. Echocardiographic criteria were used to assess PV residual lesion severity at discharge (class 1: no residua; class 2: minor residua; class 3: major residua). Competing risk models were used to develop a weighted risk score for late reintervention.

RESULTS

Of 437 patients who met entry criteria, there were 81 (18.5%) reinterventions at a median follow-up of 15.6 (interquartile range, 5.5-22.2) years. On univariable analysis, minor and major PV residua, age, single-ventricle physiology, infracardiac and mixed TAPVC, and preoperative obstruction were associated with late reintervention (all P < .05). The final risk prediction model included PV residua (class 2: subdistribution hazard ratio [SHR], 4.8; 95% CI, 2.8-8.1; P < .001; class 3: SHR, 6.4; 95% CI, 3.5-11.7; P < .001), age <1 year (SHR, 3.3; 95% CI, 1.3-8.5; P = .014), and preoperative obstruction (SHR, 1.8; 95% CI, 1.1-2.8; P = .015). A risk score comprising PV residua (class 2 or 3: 3 points), age (neonate or infant: 2 points), and obstruction (1 point) was formulated. Higher risk scores were significantly associated with worse freedom from reintervention (P < .001).

CONCLUSIONS

A risk prediction model of late reintervention may guide prognostication of high-risk patients after TAPVC repair.

Management of Complex Pulmonary Vein Stenosis at Altitude Combining Comprehensive Percutaneous Interventional Treatment with Sirolimus, Pulmonary Hypertension Medications and Intraluminal Imaging with Optical Coherence Tomography

BACKGROUND

Pulmonary vein stenosis (PVS) is a growing problem for the pediatric congenital heart population. Sirolimus has previously been shown to improve survival and slow down the progression of in-stent stenosis in patients with PVS. We evaluated patients before and after initiation of sirolimus to evaluate its effects on re-intervention and vessel patency utilizing Optical Coherence Tomography (OCT).

METHODS

We performed a retrospective study, reviewing the charts of patients with PVS, who had been prescribed sirolimus between October 2020 and December 2021. OCT was performed in the pulmonary vein of interest as per our published protocol. Angiographic and OCT imaging was retrospectively reviewed. Statistical analysis was performed using Chi square and Wilcoxon signed-rank test to compare pre-and post-sirolimus data.

RESULTS

Ten patients had been started and followed on sirolimus. Median age at sirolimus initiation was 25 months with median weight of 10.6 kg and average follow-up of 1 year. Median total catheterizations were 7 for patients prior to starting sirolimus and 2 after starting treatment (p = 0.014). Comparing pre- and post-sirolimus, patients were catheterized every 3 months vs every 11 months (p = 0.011), median procedure time was 203 min vs 145 min (p = 0.036) and fluoroscopy time, 80 min vs 57.2 min (p = 0.036). 23 veins had severe in-stent tissue ingrowth prior to SST (luminal diameter < 30% of stent diameter). Post-sirolimus, 23 pulmonary veins had moderate to severe in-stent tissue ingrowth that responded to non-compliant balloon inflation only with stent luminal improvement of > 75%.

CONCLUSION

Our study suggests that the addition of sirolimus in patients with moderate-severe PVS helps to decrease disease progression with decrease frequency of interventions. Reaching therapeutic levels for sirolimus is critical and medication interactions and side-effects need careful consideration. OCT continues to be important for evaluation and treatment guidance in this patient population.

Bioresorbable PPDO sliding-lock stents with optimized FDM parameters for congenital heart disease treatment

Stent implantation has been a promising therapy for congenital heart disease (CHD) due to better efficacy. Compared to permanent metal stents, bioresorbable polymer stents have shown a great advantage in accommodating the vascular growth of pediatric patients, but the application is still limited due to inferior radial strength. Here, bioresorbable poly(p-dioxanone) (PPDO) sliding-lock stents for CHD treatment were fabricated by fused deposition modeling (FDM). The effects of FDM processing parameters, including nozzle temperature, bed temperature, layer thickness, and printing speed, on the mechanical properties of PPDO parts were investigated to optimize the processing condition to enhance the radial strength of stents. Finite element analysis (FEA) was also used to evaluate the mechanical properties of stents. PPDO sliding-lock stents fabricated under optimized FDM parameters showed radial strength of 3.315 ± 0.590 N/mm, superior to benchmark commercial metal stents. Radial strength curve and compression behavior of PPDO sliding-lock stents were investigated. Results of FEA exhibited that strut width, shape of the mesh cell and surface coverage ratio had an impact on the compression force of PPDO sliding-lock stents. PPDO sliding-lock stents fabricated with optimized FDM parameters show favorable mechanical performance and meet the requirement of CHD treatment.

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.

"Half-uncovered technique" to secure larger stents for postoperative pulmonary vein stenosis

Although larger stent placement could be effective for pulmonary vein stenosis, stents extrusion tends to occur due to caliber narrowing, small landing area, and the slippery nature. We placed stents with diameter ≧8 mm for four stenotic lesions using the "half-uncovered technique". All stents were precisely placed and successfully resolved the stenosis. This technique allows us to avoid extrusion and to perform safe and effective dilatation when placing larger stents for pulmonary vein stenosis.

Transcatheter Cardiac Interventions in the Newborn: JACC Focus Seminar

For neonates with critical congenital heart disease requiring intervention, transcatheter approaches for many conditions have been established over the past decades. These interventions may serve to stabilize or palliate to surgical next steps or effectively primarily treat the condition. Many transcatheter interventions have evidence-based records of effectiveness and safety, which have led to widespread acceptance as first-line therapies. Other techniques continue to innovatively push the envelope and challenge the optimal strategies for high-risk neonates with right ventricular outflow tract obstruction or ductal-dependent pulmonary blood flow. In this review, the most commonly performed neonatal transcatheter interventions will be described to illustrate the current state of the field and highlight areas of future opportunity.

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.

Retrograde Pulmonary Vein Recanalization Using Transcatheter Electrosurgery

Transcatheter electrosurgery is a wire-based technique used to traverse or cut tissue within blood-filled spaces using alternating current delivered by guidewires or catheters. The use of transcatheter electrosurgical techniques in the pediatric population has been limited. We are reporting the first case of retrograde pulmonary vein recanalization using transcatheter electrosurgery. (Level of Difficulty: Advanced.)

Pulmonary Arteriovenous Malformation and Its Vascular Mimickers

Pulmonary arteriovenous malformation (AVM) is a congenital vascular disease in which interventional radiologists can play both diagnostic and therapeutic roles in patient management. The diagnosis of pulmonary AVM is simple and can usually be made based on CT images. Endovascular treatment, that is, selective embolization of the pulmonary artery feeding the nidus of the pulmonary AVM, and/or selectively either the nidus or draining vein, has become a first-line treatment with advances in interventional devices. However, some vascular diseases can simulate pulmonary AVMs on CT and pulmonary angiography. This subset can confuse interventional radiologists and referring physicians. Vascular mimickers of pulmonary AVM have not been widely known and described in detail in the literature, although some of these require surgical correction, while others require regular follow-up. This article reviews the clinical and radiologic features of pulmonary AVMs and their mimickers.

This and that: management of Tetralogy of Fallot and pulmonary vein stenosis in an infant—a case report

Background

Tetralogy of Fallot (TOF) is the most common congenital cyanotic cardiac lesion. Pulmonary vein stenosis occurs much less commonly and remains difficult to manage. It is exceedingly uncommon for a patient to have both lesions. This case highlights the diagnostic and management difficulties in an infant with these two lesions.

Case summary

The patient is a 4-month-old female infant with a history of TOF status post right ventricular outflow tract stent placement who presented after a hypoxaemic event at home to 40% SpO2. Computed tomography angiography demonstrated previously undiagnosed pulmonary vein stenosis of all four veins. She underwent multiple catheter-based palliations including balloon dilations and stent placements in each pulmonary vein in order to maximize her chances of successful definitive repair. She underwent successful repair of her TOF and pulmonary vein stenosis at ten months of age.

Discussion

The combination of TOF and pulmonary vein stenosis is not common, but when these lesions co-occur, they present a significant dilemma in determining the timing of surgery in order to optimize the odds of a successful outcome. This case demonstrates that serial catheter-based procedures can be valuable tools in minimizing pre-operative risk factors and highlights one strategy in determining timing of definitive surgical repair.

Aspiration Is Associated with Poor Treatment Response in Pediatric Pulmonary Vein Stenosis

Intraluminal pulmonary vein stenosis is a disease with significant morbidity and mortality, though recent progress has been made using multimodal therapy with antiproliferative agents. The aim of this study was to evaluate the association between aspiration and poor treatment response in patients with intraluminal pulmonary vein stenosis. A retrospective, single-center cohort analysis was performed of patients treated with a combination of imatinib mesylate and multimodal anatomic relief between March 2009 and November 2019. Analysis focused on 2-ventricle patients due to small numbers and clinical heterogeneity of single ventricle patients. Among the 84 patients included, 15 had single ventricle physiology and 69 had 2-ventricle physiology. Among the 2-ventricle group, multivariable analysis revealed that patients with clinical aspiration had nearly five times higher odds of poor treatment response than patients without aspiration (OR 4.85, 95% CI [1.37, 17.2], p = 0.014). Furthermore, male patients had higher odds of poor treatment response than their female counterparts (OR 3.67, 95% CI [1.04, 12.9], p = 0.043). Aspiration is a novel, potentially modifiable risk factor for poor treatment response in pediatric multi-vessel intraluminal pulmonary vein stenosis in patients with 2-ventricle physiology.

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.

Computed tomography-based surgical strategy for total anomalous pulmonary venous connection

OBJECTIVES

We used computed tomographic angiography (CTA)-based surgical planning to clarify the anatomical indications of sutureless repair technique for total anomalous pulmonary venous connection. The mid-term impact of the current surgical strategies was evaluated.

METHODS

One hundred twelve patients underwent repair for total anomalous pulmonary venous connection. The study period was divided into era 1 (1996-2010, n = 56) and era 2 (2011-2018, n = 56). Patients with single ventricular heart (SVH) were included. In era 2, the indications for primary sutureless repair and branch pulmonary vein incision were based on CTA findings.

RESULTS

For patients with biventricular heart, the 5-year survival was 69% and 97% in eras 1 and 2, respectively (P = 0.0024). For patients with SVH, the 5-year survival was 21% and 70% in eras 1 and 2, respectively (P = 0.0007). During the follow-up period, the evidence of post-repair pulmonary vein stenosis (PVS) was observed in 12 patients with biventricular heart [era 1, 8 patients (23%); era 2, 4 patients (13%)], and 14 patients with SVH [era 1, 6 patients (60%); era 2, 8 patients (36%)]. Using multivariable analysis, preoperative CTA was associated with improved survival in both biventricular heart and SVH and associated with post-repair PVS-free survival in SVH. Since 2011, 12 patients with post-repair PVS underwent multiple reintervention with 1 recorded death (5-year survival: 88%).

CONCLUSIONS

CTA-based surgical strategy for total anomalous pulmonary venous connection provided significant survival benefit. Although post-repair PVS could occur in era 2, aggressive reintervention appeared to be associated with improved survival and vein patency.

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.

Outcomes in Establishing Individual Vessel Patency for Pediatric Pulmonary Vein Stenosis

The purpose of this study was to determine what patient and pulmonary vein characteristics at the diagnosis of intraluminal pulmonary vein stenosis (PVS) are predictive of individual vein outcomes. A retrospective, single-center, cohort sub-analysis of individual pulmonary veins of patients enrolled in the clinical trial NCT00891527 using imatinib mesylate +/− bevacizumab as adjunct therapy for the treatment of multi-vessel pediatric PVS between March 2009 and December 2014 was performed. The 72-week outcomes of the individual veins are reported. Among the 48 enrolled patients, 46 patients and 182 pulmonary veins were included in the study. Multivariable analysis demonstrated that patients with veins without distal disease at baseline (odds ratio, OR 3.69, 95% confidence interval, CI [1.52, 8.94], p = 0.004), location other than left upper vein (OR 2.58, 95% CI [1.07, 6.19], p = 0.034), or veins in patients ≥ 1 y/o (OR 5.59, 95% CI [1.81, 17.3], p = 0.003) were at higher odds of having minimal disease at the end of the study. Veins in patients who received a higher percentage of eligible drug doses required fewer reinterventions (IRR 0.76, 95% CI [0.68, 0.85], p < 0.001). The success of a multi-modal treatment approach to aggressive PVS depends on the vein location, disease severity, and drug dose intensity.

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.

Treatment of Congenital and Acquired Pulmonary Vein Stenosis

PURPOSE OF REVIEW

Pulmonary vein stenosis (PVS) is a rare entity that until the last 2 decades was seen primarily in infants and children. Percutaneous and surgical interventions have limited success due to relentless restenosis, and mortality remains high. In adults, acquired PVS following ablation for atrial fibrillation has emerged as a new syndrome. This work will review these two entities with emphasis on current treatment.

RECENT FINDINGS

Greater emphasis on understanding and addressing the mechanism of restenosis for congenital PVS has led to the use of drug-eluting stents (DES) and systemic drug therapy to target neo-intimal growth. Frequent reinterventions are positively affecting outcomes. Longer-term outcomes of percutaneous treatment for acquired PVS are emerging. Treatment of congenital PVS continues to be plagued by restenosis. DES show promise, but frequent reinterventions are required. Larger upstream vein diameter predicts success for congenital and acquired PVS interventions. Efforts to induce/maintain vessel growth are important for future treatment strategies.

Preliminary findings on the use of intravascular ultrasound in the assessment of pediatric pulmonary vein stenosis

OBJECTIVE

Determine the feasibility of performing intravascular ultrasound (IVUS) in pediatric pulmonary vein stenosis (PVS) and investigate whether IVUS can delineate the mechanism of PVS.

BACKGROUND

The use of IVUS in pediatric patients with PVS has not been reported.

METHODS

Retrospective, single center, cohort analysis of all patients who underwent IVUS of pulmonary veins from August 2016 to December 2019.

RESULTS

IVUS was performed on 81 pulmonary veins in 50 pediatric patients (median age = 1.7 years [0.9, 3.1], median weight = 8.6 kg [7.3, 11.8]). All veins accepted the IVUS catheter (.014 or .018), with adequate visualization in 88% (71/81) of imaged veins, and improvement in visualization in the more recent period (23/24; 96%). Veins were categorized as having presumed intimal thickening (PIT) with luminal narrowing (n = 36), ostial narrowing without PIT (n = 14), distortion/compression (n = 6), normal (n = 2), and stent with (n = 9) or without in-stent stenosis (n = 4). In veins with at least 6 months of follow up, (re)intervention occurred more commonly in veins with PIT (14/19; 74%) versus veins without PIT (3/13; 23%; p = 0.01). There were no IVUS related adverse events.

CONCLUSION

IVUS can be used safely in pediatric patients and can reliably demonstrate vein lumen and wall architecture. With further refinement, IVUS has the potential to differentiate intimal neo-proliferation from other mechanisms of obstruction. The exact role of IVUS in the assessment of pediatric PVS is yet to be determined.

Paclitaxel-coated drug-eluting balloon for pulmonary vein stenosis after repair of total anomalous pulmonary venous return with asplenia

We used a paclitaxel-coated drug-eluting balloon (DEB) for pulmonary vein stenosis (PVS) after repair of total anomalous pulmonary venous return with asplenia. No adverse effect of paclitaxel was revealed and plasma concentration of paclitaxel was not elevated after intervention. Although progression of PVS slowed after dilatation with the DEB, stenosis recurred relentlessly, resulting in patient demise. This strategy may be safe for infantile cases, but requires further effective strategy, such as usage of larger sizes of DEBs. <Learning objective: Paclitaxel-coated drug-eluting balloons may be safely used for pulmonary vein stenosis after total anomalous pulmonary venous return repair in an infant with asplenia. However, their effectiveness is still limited.>.

Percutaneous Pulmonary Vein Stenting to Treat Severe Pulmonary Vein Stenosis After Surgical Reconstruction

A 36-year-old female underwent left lower lobectomy with left atrial and left upper pulmonary vein (LUPV) reconstruction with a bovine pericardial patch for an intrathoracic pheochromocytoma. Postoperatively, she developed shortness of breath and transesophageal echocardiography demonstrated LUPV stenosis with increased velocities. Computed tomography angiogram of the chest revealed LUPV stenosis at the left atrium ostium with an area of 39 mm². Under angiographic and echocardiographic guidance, a 10 × 19 mm Omnilink Elite uncovered stent was deployed in the LUPV ostia. While reported following left atrial ablation, pulmonary vein stenting can be successful in a pulmonary vein surgically reconstructed with bovine pericardium.

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.

Long-term outcome of percutaneous intervention for pulmonary vein stenosis after pulmonary vein isolation procedure

OBJECTIVES

Report long-term outcomes of percutaneous intervention in patients with pulmonary vein stenosis (PVS) after pulmonary vein isolation (PVI) from a single center over 16 years.

BACKGROUND

Outcome reports of percutaneous intervention for PVS resulting from PVI are limited.

METHODS

Retrospective review of all patients with PVS after PVI who underwent percutaneous intervention at the Cleveland Clinic Foundation between January 2000 and December 2016.

RESULTS

A total of 205 patients underwent cardiac catheterization for PVS during the study period. Completely occluded veins which could not be recanalized occurred in six patients. Of the remaining 199 patients, 27 (14%) were lost to follow-up, leaving 172 patients with 276 veins for analysis. Balloon angioplasty was performed in 62 veins and stent implantation in 250 (primary in 214, to treat postdilation restenosis in 36). Re-intervention occurred in 45/62 (73%) balloon-dilated veins and 45/250 (18%) stented veins. Freedom from re-intervention at 1 and 5 years was 90 and 73% following stenting versus 40 and 23% following balloon dilation (p < .001, Hazard ratio (HR) = 5.7). Veins with stent diameter ≥7 mm (n = 231) had greater freedom from re-intervention (95% at 1 year, 79% at 5 years) than veins with stents <7 mm (43% at 1 year, 9% at 5 years), p < .001. There was clear symptomatic improvement after intervention and no procedural mortality.

CONCLUSIONS

Stent implantation at ≥7 mm for PVS after PVI is associated with low rates of re-intervention, in contrast to balloon dilation and stenting with small conventional stents.