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Lung Lesions: Fetal Interventions Parts I+II

Video Published 2019-01-11 Updated 2022-08-22

Timestops (8)

Topic Overview

A multidisciplinary discussion on fetal interventions for congenital lung lesions, primarily congenital cystic adenomatoid malformations (CCAMs) and bronchopulmonary sequestrations. The conversation centers on indications for fetal surgery, EXIT procedures, and less-invasive interventions such as pleuro-amniotic shunts. Key clinical points include: CVR >1.6 predicts hydrops risk in microcystic lesions; most congenital lung lesions do not require prenatal intervention; EXIT procedures demand specialized maternal-fetal teams and are reserved for cases with severe compression and high CVR; and attempts at vessel ablation or sclerotherapy carry significant risks including systemic thrombosis and unknown neurodevelopmental effects from alcohol injection.

Key Takeaways

  • CVR >1.6 in microcystic CCAM predicts <5% hydrops risk; EXIT reserved for CVR >2 with severe compression signs. (0:46)
  • EXIT procedures require 15-20 person teams, weeks of planning, and maternal expertise; 3-5 cases/year minimum volume. (5:13)
  • 95% of congenital lung lesions are prenatally diagnosed, but almost none require prenatal intervention. (18:11)
  • Alcohol sclerotherapy risks systemic thrombosis and unknown neurodevelopmental effects; avoid in fetal interventions. (16:27)
  • Patients with prior fetal surgery must never labor due to classical uterine incision; future deliveries require cesarean. (2:59)

Inside this episode

Kai, the Library's AI content creator, listened to this episode and mapped who's speaking, the chapters, key claims, and cases. Every item links to the exact moment in the recording.

AI-enriched

Who's speaking

  • Jack — guest
  • Alan — guest
  • Speaker 3 — guest
  • Speaker 4 — host
  • Jean-Martin — guest
  • Speaker 6 — guest

Chapters

  • 0:00EXIT Procedure Indications and Technique — Discussion of EXIT procedure use for large CCAMs, selection criteria (CVR >2, compression signs), and technical considerations including maternal anesthesia and uterine relaxation requirements.
  • 3:41EXIT Program Development and Requirements — Requirements for establishing an EXIT program: maternal-fetal expertise, anesthetic team experience, adequate case volume (3-5/year minimum), and the complexity of multidisciplinary coordination involving 15-20 team members.
  • 7:57Management of Sequestrations with Systemic Vessels — Discussion of bronchopulmonary sequestrations with large feeding vessels, mechanisms of hydrops (mass effect vs high-output failure), and risks of vessel ablation techniques including alcohol injection and radiofrequency ablation.
  • 10:10Technical Aspects of Fetal Lobectomy — Fetal tissue characteristics at 20-23 weeks (gelatinous, friable), positioning techniques using amniotic fluid buoyancy, and comparison to neonatal surgery. No successful fetal pneumonectomies reported; bilobectomies performed with dramatic compensatory growth of residual lung.
  • 12:50Vessel Occlusion Attempts and Complications — Toronto center's experience with vessel occlusion (radiofrequency ablation, coils, alcohol injection) showing mixed results. Concerns raised about alcohol causing systemic thrombosis and unknown neurodevelopmental effects, and radiofrequency causing uncontrolled collateral thermal damage in high-water-content fetal tissues.
  • 18:09Natural History and Regression of Congenital Lung Lesions — Emphasis that 95% of prenatally diagnosed CCAMs do not require intervention. Discussion of lesion regression vs disappearance: true cystic CCAMs regress but remain visible on postnatal CT, while some bronchial stenosis cases may appear to resolve. Importance of fetal evaluation to prevent inappropriate termination recommendations.
  • 21:42Nomenclature and EXIT Indication Pitfalls — Recommendation to use 'congenital lung lesions' rather than 'CCAM' for prenatal diagnosis since CCAM is a pathological diagnosis. Case example of EXIT performed for presumed large CCAM that was actually congenital lung agenesis, highlighting the critical importance of accurate prenatal diagnosis.
  • 25:00Referral Criteria and Diagnostic Workup — Indications for fetal center referral: inability to manage complications, inadequate monitoring capability, or lack of intervention capacity. CVR 1.6 threshold for hydrops risk in microcystic lesions. Pleuro-amniotic shunts reserved for macrocystic lesions with true hydrops (not isolated ascites). Role of fetal MRI varies by center resources and case complexity.

Key claims

  • 27:50CVR greater than 1.6 in microcystic CCAM lesions predicts less than 3-5% likelihood of evolving hydrops — Alan
  • 0:46EXIT procedures at CHOP are reserved for cases with average CVR over 2, evidence of compression including diaphragmatic aversion and marked mediastinal shift — Alan
  • 1:41It is very rare to need ECMO in CCAM patients — Alan
  • 2:46There is no clear reduction in ability to have subsequent pregnancy after fetal surgery — Alan
  • 2:59Patients who have had fetal surgery should never labor with future pregnancies due to classical cesarean-type uterine incision — Alan
  • 3:22No cases of placenta accreta at hysterotomy site have been observed following fetal surgery — Alan
  • 4:03EXIT procedure requires anesthetic team expertise in uterine relaxation and maternal issues, distinct from standard cesarean section — Alan
  • 4:49CHOP has performed close to 100 EXIT procedures in the past 10 years — Alan
  • 5:13Maternal expertise must be available at the hospital performing EXIT procedures to protect the mother — Speaker 6
  • 6:04Four or five centers in the US clearly have qualifications and background to do good EXIT procedures — Alan
  • 6:56EXIT procedures require weeks of planning and involve 15-20 people in the team — Speaker 6
  • 7:15One EXIT procedure per year is probably not enough volume to justify doing them; 3-5 per year is a reasonable threshold — Alan
  • 8:27Most bronchopulmonary sequestrations causing hydrops have associated pleural effusions and mediastinal shift rather than high-output failure physiology — Alan
  • 16:27Injecting alcohol into fetal vessels has potential for systemic thrombosis, with documented case of thrombi in heart chambers — Alan
  • 17:06Neurologic effects of using alcohol as sclerosant in the fetus have not been adequately studied and are very worrisome — Alan
  • 17:26Radiofrequency ablation in fetus causes uncontrolled heat dispersion due to 90% water content, with energy dispersing unpredictably and causing collateral damage — Alan
  • 18:11Probably 95% of CCAMs seen now are prenatally diagnosed — Speaker 6
  • 18:18Almost none of prenatally diagnosed congenital lung lesions require prenatal intervention, and very few require intervention the day the child is born — Speaker 6
  • 19:46Many large congenital lung lesions have been referred after recommendation for termination by practitioners who don't understand natural history — Alan
  • 20:56True cystic CCAMs often regress and become isoechogenic in third trimester but remain present and prominent on CT scan one month after birth — Alan
  • 22:18CCAM is a pathological diagnosis once specimen is in the bucket, not a prenatal diagnosis — Jean-Martin
  • 22:18Congenital lung lesions should be classified as macrocystic, hyperechoic, or mixed rather than called CCAMs prenatally — Jean-Martin
  • 23:58Lung agenesis is frequently misdiagnosed as microcystic CCAM elsewhere and referred to fetal centers — Alan
  • 24:25EXIT is more invasive than regular C-section for the mother — Jean-Martin
  • 25:34Pleuro-amniotic shunts are used specifically for macrocystic CCAMs with evidence of hydrops — Alan
  • 25:50Hydrops requires more than just ascites; must include pleural effusion, pericardial effusion, and skin or scalp edema — Alan
  • 25:53Pure ascites is not necessarily hydrops and can be related to mediastinal shift and hepatic venous return — Alan
  • 10:53Fetal tissue at 20-23 weeks becomes very gelatinous and friable, requiring careful handling — Alan
  • 11:48Fetus is anesthetized from maternal anesthesia plus direct fetal anesthetic and paralytic injection — Alan
  • 13:43Small piece of residual lung tissue grows dramatically after fetal lobectomy as long as airway and vasculature are preserved — Alan
  • 12:58No successful fetal pneumonectomies have been performed; one case of bronchial atresia with attempted pneumonectomy resulted in fetal death — Alan
  • 14:08Most C-sections are done through lower uterine segment and do not interfere with fetal surgery incision — Alan

Cases discussed

  • 15:10Bronchopulmonary sequestration or hybrid lesion with large feeding vessel managed with shunt and vessel occlusion
  • 15:52Vessel occlusion attempt using radiofrequency ablation
  • 15:59Vessel occlusion using coils
  • 16:27Teratoma with alcohol injection for sclerotherapy
  • 17:38Teratoma with radiofrequency ablation
  • 23:01Presumed large hyperechoic lung lesion in obese mother
  • 13:04Bronchial main stem atresia with attempted fetal pneumonectomy

Points of disagreement

  • 0:17Frequency of EXIT procedure use for CCAMs
    • Jack: Toronto has not had cases requiring EXIT with lobectomy
    • Alan: CHOP may have overused EXIT with CCAMs but believes most cases were justified given severity (CVR >2, compression signs)
  • 20:56Whether CCAMs can truly disappear
    • Speaker 3: Has seen patients where hydrops resolved and CCAM could not be found after birth despite CT scan
    • Alan: True cystic CCAMs regress but do not disappear; always present on postnatal CT. Some apparent disappearances are likely bronchial stenosis cases misdiagnosed as CCAM

Open questions

  • What is the true incidence of high-output cardiac failure as mechanism of hydrops in bronchopulmonary sequestrations with large systemic feeding vessels?
  • What are the neurodevelopmental effects of alcohol injection into fetal circulation?
  • How many centers worldwide perform EXIT procedures with appropriate expertise and volume?
  • Should there be a registry for fetal surgery and EXIT procedures similar to the ECMO registry?
  • What is the optimal management for hybrid lesions (CCAM with systemic feeding vessel) that develop hydrops?
  • Can fetal MRI reliably distinguish between true CCAM and bronchial stenosis/atresia that mimics CCAM appearance?
This episode was analyzed and enriched by Kai, the Library's AI content creator. Every item links to the moment it comes from — click a timestamp to listen in context.
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