Pediatric and Congenital Vascular Surgery

68.1Definition and clinical presentation

Pediatric vascular conditions encompass vascular anomalies, congenital structural defects, acquired aneurysms, inherited aortopathies, and pediatric thrombosis. The clinical presentation is defined by the underlying disease mechanism:

• Vascular anomalies: The ISSVA classification divides these into vascular tumors, which are proliferative lesions such as infantile hemangioma, and vascular malformations, which enlarge by expansion of developmental anomalies without proliferation ISSVA 2018.
• Aortic coarctation: Presents with a hemodynamic gradient, upper-to-lower extremity blood-pressure discrepancy, collateral formation, and associated arch hypoplasia AHA/ACC 2018.
• Pediatric venous thromboembolism: Renal vein thrombosis presents as neonatal or childhood disease defined by laterality, renal impairment, and inferior vena cava extension ACCP 2012.
• Kawasaki disease: An acute childhood vasculitis resulting in coronary artery aneurysms that carry a long-term risk of thrombosis, stenosis, and myocardial infarction AHA 2017.
• Heritable aortopathy: Thoracic aortic dilation presenting alongside a syndromic phenotype, a family history of early dissection, or an identified pathogenic familial variant AHA 2024.

68.2Classification and risk stratification

Anatomic and physiologic classification determines intervention thresholds across pediatric conditions. Vascular malformations are categorized by the ISSVA system as simple, combined, involving major named vessels, or associated with other anomalies ISSVA 2018.

Kawasaki coronary artery aneurysms are classified by z-score and absolute diameter. Small aneurysms have a z-score of 2.5 to < 5. Medium aneurysms have a z-score of 5 to < 10 and an absolute dimension < 8 mm. Large or giant aneurysms, which carry the highest ischemic risk, have a z-score >= 10 or an absolute dimension >= 8 mm AHA 2017.

Hypertension risk stratification requires ambulatory blood pressure monitoring to confirm true hypertension and exclude white-coat hypertension, which accounts for 30 to 40 percent of elevated office readings. Ambulatory monitoring is required to detect masked hypertension after coarctation repair and in patients with chronic kidney disease or diabetes AAP 2017.

Aortopathy risk stratification is guided by genetic testing. Testing is indicated for patients with a thoracic aortic aneurysm and a first-degree relative with aortic disease or a suspected heritable syndrome, including Marfan (FBN1), Loeys-Dietz (TGFBR1, TGFBR2, SMAD3, TGFB2), vascular Ehlers-Danlos (COL3A1), and ACTA2-related disease. Identification of a pathogenic variant triggers cascade testing in first-degree relatives and alters aortic surveillance intervals AHA 2024 · ACC/AHA 2022. Management extends to serial echocardiographic surveillance at guideline intervals and referral for prophylactic aortic root surgery when the aortic dimension reaches syndrome-specific thresholds, informed by absolute size, growth rate, family history, and syndrome.

68.3Treatment decision and operative thresholds

Pediatric vascular interventions require modality selection tailored to patient size, future growth, and durable organ function. Management pathways are distinct for each disease category.

1. Classify vascular anomalies to separate proliferating tumors requiring early medical assessment from malformations managed by targeted observation, medical therapy, or staged interventional treatment: image-guided sclerotherapy for low-flow (venous, lymphatic) lesions, catheter embolization for high-flow (arteriovenous) lesions, and surgical excision for selected localized or symptomatic lesions.
2. Stratify renal vein thrombosis by laterality, renal function, and caval extension to dictate antithrombotic intensity.
3. Determine the coarctation repair route based on patient age, arch hypoplasia severity, collateral burden, and anatomic suitability for catheter-based intervention.

68.4Medical therapy and secondary prevention

Medical therapy targets specific tumor proliferation or complex malformation biology. Propranolol is the standard agent for high-risk infantile hemangiomas, dosed at 1 to 3 mg of propranolol base per kilogram of body weight per day Léauté-Labrèze 2015. Sirolimus is used for complicated vascular anomalies, demonstrating partial response in generalized lymphatic anomalies, kaposiform hemangioendothelioma with Kasabach-Merritt phenomenon, capillary-lymphatic-venous malformations, PTEN-related arteriovenous malformations, and venous-lymphatic malformations Adams 2016.

Pediatric venous thromboembolism protocols employ unfractionated heparin or low-molecular-weight heparin scaled to pediatric physiology and bleeding risk rather than adult-derived regimens ACCP 2012. Kawasaki coronary aneurysms are managed with coordinated antiplatelet or anticoagulant regimens scaled to the exact z-score risk stratum to mitigate long-term thrombosis and myocardial infarction risk AHA 2017.

All patients receive low-dose aspirin 3 to 5 mg/kg/day once afebrile AHA 2017. Small-to-medium aneurysms (z-score 2.5 to < 10) are held on low-dose aspirin alone, adding a second antiplatelet such as clopidogrel for expanding lesions. Large or giant aneurysms (z-score >= 10 or >= 8 mm) require systemic anticoagulation, warfarin targeting an INR of 2.0 to 3.0 or low-molecular-weight heparin, in addition to low-dose aspirin. Aneurysm thrombosis prompts escalation to triple therapy or thrombolysis.

68.5Areas of controversy

The efficacy of sirolimus across the spectrum of vascular malformations is not uniform. Central conducting lymphatic channel anomalies demonstrate progressive disease despite sirolimus therapy, and small patient numbers within specific ISSVA strata limit the broad extrapolation of medical therapy across all complex malformations Adams 2016 · ISSVA 2018.

The optimal modality for native aortic coarctation remains center-dependent. While surgical repair is established for neonates, young children, and those with complex arch hypoplasia, the specific anatomic and age boundaries favoring primary stent placement or balloon angioplasty over open repair in older children vary significantly among institutions AHA/ACC 2018 · CCISC 2011.