Fontan & Single Ventricle Questions¶

Question 1¶

What is the optimal central venous pressure (CVP) for Fontan circulation?

A) 2-4 mmHg B) 6-8 mmHg C) 12-15 mmHg D) 18-20 mmHg E) >20 mmHg

Answer

**Correct Answer: C** Fontan CVP goals: - **12-15 mmHg** provides adequate driving pressure - Too low (<10) = inadequate pulmonary blood flow - Too high (>18) = Fontan failure, venous congestion Fontan gradient (CVP - LAP) should be <5-6 mmHg. **Board Pearl:** Fontan CVP target = 12-15 mmHg; gradient <5-6 mmHg

Question 2¶

A Fontan patient has albumin of 1.8 g/dL, diarrhea, and ascites. Alpha-1 antitrypsin is elevated in stool. What is the expected immunologic finding?

A) Elevated IgG B) Lymphopenia C) Neutrophilia D) Elevated T-cells E) Normal immunoglobulins

Answer

**Correct Answer: B** **PLE immunologic features**: - Hypogammaglobulinemia (lose immunoglobulins) - **Lymphopenia** (lose lymphocytes enterically) - Increased infection risk - May need IVIG replacement **Board Pearl:** PLE = hypoalbuminemia + hypogammaglobulinemia + lymphopenia

Question 3¶

What percentage of Fontan patients develop atrial arrhythmias by 20 years post-Fontan?

A) 10-15% B) 20-30% C) 40-50% D) 60-70% E) >80%

Answer

**Correct Answer: C** Fontan arrhythmia incidence: - **40-50%** by 20 years - IART (flutter) most common - Poorly tolerated (loss of AV synchrony) - May need ablation, pacemaker, conversion **Board Pearl:** 40-50% Fontan patients have arrhythmias by 20 years; IART most common

Question 4¶

Fontan-associated liver disease (FALD) includes which pathologic finding?

A) Hepatocellular carcinoma B) Congestive hepatopathy with fibrosis C) Acute hepatitis D) Biliary cirrhosis E) Hepatic steatosis only

Answer

**Correct Answer: B** **FALD features**: - Congestive hepatopathy from elevated CVP - Progressive fibrosis/cirrhosis - Risk of hepatocellular carcinoma (HCC) - Surveillance required (ultrasound + AFP) Nearly universal after 10-15 years of Fontan. **Board Pearl:** FALD = congestive fibrosis; HCC surveillance needed

Question 5¶

A 25-year-old Fontan patient wants to become pregnant. What counseling is appropriate?

A) Pregnancy is absolutely contraindicated B) Pregnancy carries high maternal and fetal risk - requires careful counseling C) Pregnancy outcomes are similar to normal population D) Only cesarean delivery is safe E) First-trimester termination is mandatory

Answer

**Correct Answer: B** Fontan pregnancy: - **High risk** but not absolutely contraindicated - Maternal complications: arrhythmias, HF, thrombosis - Fetal risks: prematurity, IUGR, loss (~30% miscarriage) - Requires high-risk OB + cardiology team - Pre-conception optimization essential **Board Pearl:** Fontan pregnancy = high risk but not absolutely contraindicated; multidisciplinary care essential

Question 6¶

What anticoagulation strategy is most commonly used for Fontan patients without fenestration?

A) No anticoagulation needed B) Aspirin alone is standard C) Warfarin INR 2-3 is standard D) DOAC is standard E) Practice varies - aspirin, warfarin, or DOAC used

Answer

**Correct Answer: E** Fontan anticoagulation: - **No consensus** - varies by center - Aspirin alone used at some centers - Warfarin INR 2.0-3.0 at others - DOACs emerging but limited data - Fenestrated Fontan → anticoagulation preferred **Board Pearl:** Fontan anticoagulation = no consensus; options include ASA, warfarin, DOACs

Question 7¶

What test should be performed annually for hepatocellular carcinoma screening in Fontan patients?

A) CT chest B) Liver biopsy C) Liver ultrasound + AFP D) Cardiac catheterization E) Colonoscopy

Answer

**Correct Answer: C** FALD/HCC surveillance: - **Ultrasound + AFP** annually after 10 years of Fontan - MRI/CT if abnormality detected - Risk increases with duration of Fontan - Consider hepatology co-management **Board Pearl:** Fontan HCC screening = annual ultrasound + AFP (after 10 years)

Question 8¶

Plastic bronchitis in Fontan patients is caused by what mechanism?

A) Aspiration pneumonia B) Lymphatic dysfunction with airway casts C) Bacterial infection D) Allergic reaction E) Pulmonary hemorrhage

Answer

**Correct Answer: B** **Plastic bronchitis**: - Lymphatic dysfunction → lymph enters airways - Protein-rich casts obstruct bronchi - Life-threatening complication - Treatment: inhaled tPA, lymphatic intervention **Board Pearl:** Plastic bronchitis = lymphatic dysfunction; treat with inhaled tPA, lymphatic intervention

Question 9¶

What is the expected exercise capacity (peak VO2) in well-functioning Fontan patients compared to normal?

A) >90% of predicted B) 70-80% of predicted C) 50-70% of predicted D) 30-50% of predicted E) <30% of predicted

Answer

**Correct Answer: C** Fontan exercise capacity: - Typically **50-70% of predicted** peak VO2 - Limited by reduced preload and single ventricle - Chronotropic incompetence common - Trend over time prognostically important **Board Pearl:** Fontan peak VO2 = 50-70% predicted; serial trends are prognostic

Question 10¶

A Fontan patient develops sudden-onset dyspnea with reduced SpO2. CXR shows clear lungs. What should be considered?

A) Pneumonia B) Heart failure exacerbation C) Fontan pathway obstruction or pulmonary embolism D) Asthma exacerbation E) Anemia

Answer

**Correct Answer: C** Sudden dyspnea + low SpO2 in Fontan: - **Fontan pathway thrombosis/obstruction** - Pulmonary embolism - Both cause acute drop in pulmonary blood flow - CT angiography indicated - May need emergent catheterization/intervention **Board Pearl:** Acute Fontan decompensation → rule out pathway obstruction/PE