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Case 007: Failed CCHD Screen

Presentation

A full-term newborn at 26 hours of life fails CCHD screening.

Screening Results: - Right hand (pre-ductal): 97% - Right foot (post-ductal): 91% - Difference: 6%

Repeat at 1 hour: - Right hand: 96% - Right foot: 90% - Difference: 6%

Baby appears comfortable, feeding well. No respiratory distress.

Clinical Reasoning

Question 1: Does this meet fail criteria per 2025 algorithm?

Answer **YES - FAILED screen** 2025 criteria: - PASS: ≥95% in BOTH locations AND ≤3% difference - RETEST: 90-94% in either location OR >3% difference - FAIL: <90% in any location OR still abnormal after 1 retest This baby: - Post-ductal 90-94% ✓ (retest indicated) - After retest: still 90% and >3% difference - **Only 1 retest allowed in 2025 algorithm** - → FAIL → needs echocardiogram

Question 2: What is the differential diagnosis?

Answer **Cardiac causes (the targets):** - Coarctation of the aorta (most commonly missed!) - Critical aortic stenosis - Interrupted aortic arch - Hypoplastic left heart syndrome - Other ductal-dependent systemic lesions **Non-cardiac causes:** - Persistent pulmonary hypertension (PPHN) - Respiratory disease (TTN, pneumonia, RDS) - Sepsis - Congenital diaphragmatic hernia - Hemoglobinopathy affecting oximetry The **>3% difference** (pre > post-ductal) specifically suggests **right-to-left ductal shunting** → concerning for left heart obstruction.

Question 3: What workup is indicated?

Answer **Immediate:** 1. **Echocardiogram** - gold standard 2. Chest X-ray 3. Blood gas 4. Consider: CBC, blood culture if sepsis concern **Careful physical exam:** - Four-extremity blood pressures - Femoral pulse assessment - Hepatomegaly - Signs of respiratory distress **Do NOT discharge** until echo completed.

Echo Results

Echocardiogram findings: - Bicuspid aortic valve - Discrete shelf at aortic isthmus - Doppler gradient: 25 mmHg - Moderate hypoplasia of transverse arch - PDA present with bidirectional flow - Good LV function

Question 4: What is the diagnosis?

Answer **Coarctation of the aorta** with discrete shelf and transverse arch hypoplasia This is EXACTLY why coarctation is often "missed" initially: - Ductus still patent at 26 hours - Provides some lower body perfusion - As ductus closes → differential cyanosis worsens → can develop shock The CCHD screen caught this before clinical deterioration!

Management

Question 5: What is the immediate management?

Answer **Immediate:** 1. **Prostaglandin E1 (PGE1)** infusion - Starting dose: 0.05-0.1 mcg/kg/min - Maintains ductal patency - Side effects: apnea (have airway management ready), fever, hypotension 2. **Transfer to cardiac center** if not at one 3. **NPO**, IV fluids 4. **Monitoring:** - Pre- and post-ductal saturations - Four-extremity BPs - Urine output - Lactate trending

Question 6: What is the definitive treatment?

Answer **Surgical repair:** - Extended end-to-end anastomosis (preferred) - Or subclavian flap repair **Timing:** - Urgent but not emergent if PGE maintaining perfusion - Usually within days of diagnosis **Alternative (in select cases):** - Balloon angioplasty (more common for recurrent coarctation) - Stenting (older children/adolescents)

Teaching Points

  1. Coarctation is the most commonly missed lesion on CCHD screening
  2. >3% difference suggests right-to-left ductal shunting
  3. PGE1 is lifesaving for ductal-dependent lesions
  4. A passed CCHD screen does NOT rule out coarctation - can present later when ductus closes
  5. 2025 algorithm: Only 1 retest allowed (faster to diagnosis)