Cardiac catheterization in neonates may serve diagnostic or therapeutic purposes. Noninvasive imaging — echocardiography, MRI, or CT — is used first when possible. A common diagnostic indication for neonatal catheterization is evaluation of pulmonary hypertension or coronary anatomy that cannot be adequately assessed noninvasively.
| Procedure | Main Use |
|---|---|
| Atrial septostomy, dilation, or atrial septal stenting | Improve atrial mixing in TGA; decompress left atrium in HLHS with restrictive/absent ASD |
| PDA, ASD, or VSD closure | Reduce pulmonary overcirculation and respiratory compromise in selected infants |
| Aortic or pulmonary valvuloplasty | Treat severe or critical valve stenosis soon after birth |
| Ductal stenting | Maintain or augment pulmonary blood flow in pulmonary stenosis or pulmonary atresia with persistent desaturation |
| Coarctation angioplasty | Stabilize severe ventricular dysfunction before surgical repair in selected cases |
| Pulmonary artery angioplasty | Treat severe congenital or postoperative pulmonary artery stenosis |
| Pulmonary vein dilation or stenting | Treat pulmonary vein stenosis with cardiorespiratory worsening, especially multiple-vein involvement with pulmonary hypertension |
| Thrombectomy, angioplasty, or stenting of occluded vessels | Treat symptomatic occlusion of central veins or arteries, often related to chronic line placement |
Infants with HLHS and no atrial communication may present with profound cyanosis and pulmonary edema immediately at birth. An EXIT or planned delivery with catheterization team on standby may be required. Delay is lethal.
Catheter closure is feasible even below 1000 g in selected centers. It avoids the surgical risks of ligation and post-closure syndrome may still occur as LV afterload increases — anticipate and monitor accordingly.
Decompressing the RV in pulmonary atresia with intact septum can be fatal if the coronary circulation depends on RV sinusoids for perfusion. Catheterization for coronary anatomy evaluation is mandatory before intervention.
Patients are generally anticoagulated with heparin during the procedure to reduce thromboembolism risk. PDA closure in smaller infants is often performed under echocardiographic guidance to reduce radiation exposure.
Catheter-related arterial thrombosis is a recognized complication after neonatal cardiac catheterization.
| Data Point | Finding |
|---|---|
| Reported CAT incidence | ~2% to 7.9% in infants |
| Vascular complication rate at 2.5–3.5 kg | ~0.9% |
| Vascular complication rate below 2.5 kg | ~6% |
| Risk factors | Lower weight, larger sheath, longer procedural time |
| Consequences of untreated CAT | Loss of future vascular access; rarely leg-length discrepancy or limb loss |
| Time After Catheterization | Assessment |
|---|---|
| Every 15 minutes × 4 | Pulse, capillary refill, limb temperature, and perfusion |
| Every 30 minutes × 2 | Pulse, capillary refill, limb temperature, and perfusion |
| Every 1 hour × 4 | Pulse, capillary refill, limb temperature, and perfusion |
| Every 4 hours for 24 hours | Continue limb and perfusion surveillance |
If pulses, temperature, capillary refill, or perfusion are abnormal at any check → obtain bedside Doppler ultrasound immediately.
| Risk Level | Definition |
|---|---|
| Low risk | Non-occlusive asymptomatic venous thrombus or chronic organized venous thrombus |
| Moderate risk | Symptomatic or acute occlusive venous thrombus without ischemia or organ failure; bilateral renal vein thrombosis; propagating venous thrombus; thrombus extending into a central vein |
| High risk | Any arterial thrombus; any thrombus causing limb ischemia or organ injury; occlusive central artery or vein; symptomatic pulmonary embolism |
| Finding | Management Direction |
|---|---|
| Negative Doppler | Routine care |
| Non-obstructive thrombus with preserved perfusion | Careful monitoring or anticoagulation depending on risk and hematology input |
| Non-limb-threatening thrombosis | Usually treat with UFH or LMWH |
| Limb-threatening thrombosis | Contact catheterization team and vascular surgery; consider embolectomy or localized tPA infusion |
UFH and LMWH are treatment-dose agents of choice for CAT. UFH is preferred when renal dysfunction is present, when procedures may be needed urgently, or when rapid reversibility with protamine is important.
If >4–8 hours have passed after catheterization: CBC, PT, PTT, fibrinogen, and D-dimer before starting.
| Step | Dose |
|---|---|
| Loading dose | 75 units/kg IV over 10 minutes |
| Maintenance infusion | Start 28 units/kg/hour |
| Test | Goal |
|---|---|
| Heparin level (anti-Xa) | 0.3–0.7 units/mL |
| PTT | 70–101 seconds |
Knowing the target is not the same as knowing what to do when the level comes back outside it. Heparin level and PTT should correlate — when they do not, look for a confounder that prolongs the PTT and so underestimates how anticoagulated the infant really is.
| Heparin level (units/mL) | PTT (seconds) | Dose adjustment | Repeat level and PTT |
|---|---|---|---|
| <0.2 | <60 | Give a 50 units/kg bolus and increase the infusion rate by 10% | 4 hours after the rate change |
| 0.2–0.29 | 60–69 | Increase the infusion rate by 10% | 4 hours after the rate change |
| 0.3–0.7 (target) | 70–101 (target) | Keep the rate the same | Every 12 hours |
| 0.71–0.8 | 102–112 | Decrease the infusion rate by 10% | 4 hours after the rate change |
| 0.81–0.99 | 113–130 | Hold the infusion for 30 minutes, then decrease the rate by 10% | 4 hours after the rate change |
| ≥1 | >130 | Repeat the heparin level; hold the infusion for 60 minutes, then decrease the rate by 15% | 4 hours after the rate change |
LMWH advantages: reaches therapeutic levels earlier, less frequent monitoring, given subcutaneously, may be administered at home by caregivers.
Do not use enoxaparin as first-line when renal dysfunction is present. Use UFH instead.
| Postmenstrual age | Initial treatment dose |
|---|---|
| <32 weeks | 2 mg/kg/dose subcutaneous every 12 hours |
| 32–40 weeks | 1.7 mg/kg/dose subcutaneous every 12 hours |
| >40 weeks | 1.5 mg/kg/dose subcutaneous every 12 hours |
| Indication | Goal Anti-Xa Level |
|---|---|
| Treatment | 0.5–1.0 units/mL |
| Prophylaxis | 0.2–0.4 units/mL |
| Anti-Xa, treatment (target 0.5–1) | Anti-Xa, prophylaxis (target 0.2–0.4) | Dose titration | Repeat level |
|---|---|---|---|
| <0.35 | <0.15 | Increase the dose by 25% | 4 hours after the next dose |
| 0.35–0.49 | 0.15–0.19 | Increase the dose by 10% | 4 hours after the next dose |
| 0.5–1 (target) | 0.2–0.4 (target) | Keep the same dose | Weekly, 4 hours after a dose |
| 1.1–1.5 | 0.41–1 | Decrease the dose by 20% | 4 hours after the next dose |
| 1.6–2 | 1.1–2 | Decrease the dose by 30% and hold the dose 3 hours past its due time | 4 hours after the next dose |
| >2 | >2 | Repeat the level; hold all doses until it falls below 0.5, then decrease the dose by 40% | Every 12 hours until the level is <0.5 units/mL |
Through the maintenance phase, haematology guides therapy until discharge or clot resolution, whichever comes first, and outpatient haematology follow-up may be needed. Usual treatment duration is 6 weeks to 3 months.
| Mistake | Better Action |
|---|---|
| Waiting until the limb is clearly ischemic before checking pulses | Perform scheduled pulse, perfusion, temperature, and capillary refill checks after every catheterization |
| Treating every small post-access thrombus the same way | Reserve treatment mainly for occlusive or clinically significant thrombi; stratify by limb threat and organ injury risk |
| Using enoxaparin first-line in renal dysfunction | Use UFH when renal dysfunction is present or rapid reversibility is needed |
| Forgetting baseline coagulation labs before UFH | Obtain CBC, PT, PTT, fibrinogen, and D-dimer when appropriate before starting UFH drip |
| Assuming PDA closure in tiny infants always requires surgery | Catheter closure can be performed in selected extremely premature infants, sometimes even below 1000 g |
| Forgetting radiation reduction strategies in small infants | PDA closure and other procedures in smaller infants can be performed under echocardiographic guidance to minimize radiation |
"Some heart problems can be treated through a catheter — a small tube placed through a blood vessel in the leg or belly button — instead of requiring open heart surgery. The heart team will explain which approach is best for your baby's specific situation."
"After catheterization, we check the baby's leg or access-site circulation very frequently for 24 hours, because a small blood clot can occasionally form where the tube was placed. We want to catch any problem early, when treatment is simplest."
"If we find a clot, the treatment depends on whether blood flow to the limb or an organ is affected. For most small clots, we use a blood-thinning medicine. For larger or more serious clots, we may involve additional specialists."