CHD

Question 1

Ebstein anomaly

From Congenital Heart Disease in the Adult Cardiac Intensive Care Unit

Maan Jokhadar MD and Joel T. Hardin MD
Critical Care Clinics, 2024-01-01, Volume 40, Issue 1, Pages 179-191,

Answer 1

->Apical displacement of the tricuspid valve,
->Adherence of the septal and posterior leaflets to the myocardium,
->Atrialization of the inlet portion of the right ventricle.
-> Usually accompanied by tricuspid regurgitation, right ventricular failure, and arrhythmias
->severity depends upon the degree of displacement of TV

Question 2

Eisenmenger Syndrome

Answer 2

• A constellation of symptoms that arises from constellation of symptoms that arise from a congenital heart defect–> initially a left-right shunt, which develops into severe pulmonary arterial hypertension (PAH) –>resulting into a right-to-left shunt–>significant hypoxemia and cyanosis that is unresponsive to O2
  M/C/C- ASD, VSD, PDA

Question 3

ASD

Answer 3

RV dilation and dysfunction
Atrial arrhythmia
Pulmonary hypertension
Paradoxic emboli

Question 4

VSD with bidirectional flow

Answer 4

Pulmonary hypertension with cyanosis (Eisenmenger syndrome)
LV volume overload, LV dilatation

Question 5

PDA small to moderate

Answer 5

LV volume overload with LV dilation and dysfunction.

Question 6

large PDA

Answer 6

Pulmonary hypertension with differential cyanosis (lower extremity cyanosis and clubbing)

Question 7

Coarctation of Aorta
Q. Associated problems & findings

Answer 7

• Hypertensive heart disease
• LV hypertrophy and dysfunction
• Stenosis, aneurysm, and pseudoaneurysm of coarctation repair site.
• Bicuspid aortic valve and aortopathy
• Cerebral berry aneurysms
• Diminished left radial pulse if subclavian flap repair

Question 8

Repaired TOF
Problems associated

Answer 8

->Significant pulmonary regurgitation common, pulmonary valve replacement often required
->PVR complications–>valve failure, endocarditis
->RV dilation and dysfunction
->Atrial and ventricular arrhythmia

Question 9

Fontan

Answer 9

• Systemic ventricle dysfunction (LV or RV).
• Conduction disease, including sick sinus syndrome and heart block, often necessitating epicardial pacemaker
• Arrhythmia (atrial and ventricular).
• Thromboembolic complications.
• Pulmonary emboli (diagnosis with CT difficult).
• Cirrhosis and its complications, including hepatocellular carcinoma.

=> Imaging – CT Pulmonary Angiography in Fontan patients:
* Risk of overdiagnosis of PE.
* Cause: differential pulmonary blood flow + streaming from SVC/IVC → artifactual filling defects.
* ⚠️ Interpretation requires congenital cardiology/radiology expertise.

Question 10

Considerations upon admission to ICU

Answer 10

• IV access
• O2 monitoring
• O2 targets
• BP monitoring

Question 11

IV Access and Embolic Risk

Answer 11

• Residual shunts are common in ACHD (ASD, VSD, Fontan fenestration).
• Risk: paradoxical emboli from IV lines → neurologic complications (ischemia, seizures).
• Precaution: all IV lines should include an in-line 0.22 μm air filter to prevent air/particulate embolism.

Question 12

Blood Pressure Monitoring

Answer 12

• Prior surgeries/shunts can cause spuriously low ipsilateral arm BP: eg-
  ->Classic Blalock-Taussig-Thomas (BTT) shunts.
  ->Subclavian flap repair for coarctation.
• If bilateral BTT shunts → measure BP from lower extremities.
• In aortic coarctation (native or residual gradient):->Adequate right arm BP may not equal distal perfusion pressure.

Question 13

Oxygenation Monitoring

Answer 13

->Pulse oximetry unreliable in:
* Cyanotic ACHD.
* Darker complexion (signal interference).
* Post-procedural/surgical vascular compromise.

->Arterial blood gas (ABG): low threshold for use when accuracy is critical.

Question 14

Oxygen Targets

Answer 14

->Cyanotic patients:
* Maintain sats at or near baseline.
* Avoid excessive O₂ supplementation → ↑ pulmonary blood flow by relieving hypoxic pulmonary vc→ risk pulmonary edema

Question 15

Classification of ACHD and physiological effects

Answer 15

⸻

1. RV Pressure Overload Lesions
   
   • Examples: Pulmonary stenosis (valvular, sub-/supra-valvular), pulmonary hypertension.
   • Pathophysiology: RV hypertrophy → dysfunction.

⸻

2. RV Volume Overload Lesions
   
   • Examples: ASD, tricuspid regurgitation,
   • Pathophysiology: RV dilation → RV dysfunction.

⸻

3. LV Pressure Overload Lesions
   
   • Examples: Aortic stenosis (valvular, sub-/supra-valvular), coarctation, systemic HTN.
   • Pathophysiology: LV hypertrophy → systolic ± diastolic dysfunction.

⸻

4. LV Volume Overload Lesions
   
   • Examples: Mitral regurgitation, aortic regurgitation, PDA, VSD (pressure-restricted, large shunts).
   • Pathophysiology: LV dilation → dysfunction.

Question 16

5). Systemic RV Lesions

Answer 16

=>Seen in - TGA

=>Key features:
* RV = systemic ventricle
- compensatory Dilatation & hypertrophy.
* Progressive systemic RV dysfunction & Failure -common late complications
* Haemodynamically significant Tricuspid regurgitation (systemic AV valve) common.

Question 17

6). Single Ventricle / Fontan Physiology

Answer 17

=>Fontan is a palliative procedure done in several conditions eg- Tricuspid atresia, Pulmonary atresia, Unbalanced ASD, Double inlet LV and Dovble outlet RV

=>Principle- Venous return is directed directly into the pulmonary arteries without a pulmonary ventricle.

=>Most adults with Fontan physiology develop multiorgan complications related to the elevated central venous pressure required to maintain the circulation eg:
->**Chronic liver congestion **(Fontan-associated liver disease) ->universal
-High risk for cirrhosis, portal hypertension, and hepatocellular carcinoma.
->Assessing volume status is particularly challenging due to the lack of jugular venous pulsatility
-> Increased risk for atrial arrhythmia, heart failure, thromboembolic complications
->CTPA–> overdiagnosis of pulmonary emboli due to differential pulmonary blood flow and streaming from the SVC and IVC with artifactual filling defects.
->Worsening cyanosis, in situ PE (sluggish pulmonary flow).
->Empiric anticoagulation often pragmatic; thrombolysis/thrombectomy in unstable PE.
-> Higher risk of hospital admission and critical illness

Question 18

7. Aortopathy / Connective Tissue Disorders

Answer 18

=>Seen in Marfan, vascular Ehlers-Danlos, Turner syndrome.
* Associations: Bicuspid aortic valve, coarctation.
* Risks: Aortic root aneurysm, dissection.
* Management: Surveillance, surgical thresholds per guidelines.

Aortopathy–>MET(Marfan’s, Ehler danlos, Turner)

Question 19

8. Cyanotic Heart Disease & Eisenmenger Syndrome

Answer 19

• Pathophysiology:
  ->Unrepaired L–R shunt (VSD, ASD, PDA) → ↑ Qp → vascular remodeling → ↑ PVR → bidirectional/R–L shunt → cyanosis.
  
  • Leads to secondary erythrocytosis, clubbing, progressive dyspnea.

=>Repairability:
* PVR < 4 WU = repairable.
* 8 WU = unrepairable.
* 4–8 WU = grey zone.

=>Management:
* Pulmonary vasodilators can help but risk pulmonary edema.
* No surgical closure once Eisenmenger established (risk of RV failure).
* Complications: Endocarditis, arrhythmia, hyperviscosity, thromboembolism, brain abscess.

Question 20

9). Ischemic Heart Disease in ACHD

Answer 20

=>Causes:
* Acquired atherosclerosis (increasing incidence with age).
* Coronary anomalies.
* Reimplanted coronaries (post arterial switch, Ross).
* Coronary fistulae.
-> Specific anomalies:
i)* Anomalous LCA from right sinus - neeeds surgical repair
ii)* ALCAPA (LCA from PA) → coronary steal → surgical repair.
iii)* Coronary fistulae: cause steal, arrhythmia → surgical/percutaneous closure if large.

Question 21

10). Aortic Arch Abnormalities

Answer 21

• Examples: Coarctation, interrupted arch, right aortic arch, double aortic arch
  ->Often surgically repaired during childhood but recoarctation can occur → treated with stents in adulthood.

Question 22

Common issues in ACHD patients requiring ICU
List 8 common complications

Answer 22

->Arrhythmias- artial and ventricular
->Conduction defects
-> Decompensation of Heart failure
->Respiratory failure
->Pulmonary haemorrhage
-> IE
->Cerebrovascular disease
->Complications of prosthetic valves

Question 23

Common issues in ACHD patients requiring ICU

Answer 23

1). Atrial and Ventricular Arrhythmias
* Increased risk due to atrial/ventricular scarring, chamber enlargement, or dysfunction.
=>Atrial arrhythmias:
* Especially destabilizing in single ventricle/Fontan and systemic RV (e.g., D-TGA atrial switch) patients.
* May precipitate hemodynamic collapse in Ebstein anomaly with concealed accessory pathways.
* Treatment:
-> Unstable → prompt cardioversion.
-> Stable → consider TEE prior to cardioversion (exclude thrombus).
* Antiarrhythmic choice must weigh risk of unmasking sinus node dysfunction; often requires pacing backup.
->IART: Very common in Fontan patients. Often elusive (esp. 2:1 conduction, mimicking sinus tachy). Adenosine can unmask.
* Many eventually require epicardial pacemakers for sinus node dysfunction or anti-tachycardia pacing.(not possible to put pacing wire thru SVC-will go into PA.

=>Ventricular arrhythmias:
* Life-threatening; emergent evaluation and therapy required.
* High risk groups:
- Tetralogy of Fallot with RV/LV dysfunction, prior ventriculotomy, prior Blalock-Taussig shunt, or QRS >180 ms.
* Management: antiarrhythmics, ablation, ICD implantation.
* Pulmonary regurgitation is a common substrate; pulmonary valve replacement often required to reduce arrhythmia burden.

Question 24

2). Cardiac Conduction Disease and Heart Block

Answer 24

->Sinus node dysfunction: common in ACHD, especially post-surgery.
->Complete heart block: may complicate surgery or arise spontaneously.
->Pacemaker considerations:
* Must carefully assess anatomy for residual septal defects.
* Risk of thromboembolism from endocardial leads across a septal defect.
* Solutions: percutaneous defect closure or epicardial lead placement.

Question 25

⸻ 3). Decompensated Heart Failure and Cardiogenic Shock

Answer 25

=>causes of ventricular dysfunction in ACHD: ->Decompensation of chronic HF ->Acute ventricular dysfunction due to - Arrhythmias, Valvular abnormalities or Ischemia =>Evaluation: detailed history and physical examination, Echocardiogram, multimodality imaging =>Systemic RV eg- TGA- * High risk for progressive decompensation. * Medical therapy: limited evidence, but typically includes beta-blockers, ACEi/ARB/ARNI, MRA, SGLT2 inhibitors. ->Decompensation management: * IV diuretics and vasodilators. * Inotropes if needed. * Advanced options: CRT, short- and long-term MCS, cardiac transplantation. * Systemic tricuspid regurgitation is common and often requires surgical intervention after stabilization.

Question 26

Hypoxic Respiratory Failure in ACHD

Answer 26

ACHD-> predisposed to hypoxic, hypercapnic, mixed respiratory failure due to unique anatomic, physiologic, and adaptive factors. Recognition of baseline physiology - essential =>Etiology * Restrictive lung disease due to multiple thoracotomies/sternotomies, surgical scarring. * Developmental lung abnormalities coexisting with congenital cardiac defects. * Cyanotic heart disease physiology ->Right-to-left shunt, secondary erythrocytosis, altered oxygen handling.

Question 27

Hypoxic Respiratory Failure in ACHD cont..

Answer 27

=>Hypoxia vs Cyanosis * Hypoxia = Reduced oxygen delivery to tissues → uniformly deoxygenated hemoglobin. * Cyanosis = Bluish discoloration from right-to-left shunting → mixed oxygenated & deoxygenated Hb. * Adaptation: Cyanotic ACHD patients develop secondary erythrocytosis, which maintains oxygen delivery despite low saturations. ->Clinical pitfall: * Do not confuse with polycythemia vera. * Do not perform routine phlebotomy (removes adaptive response, worsens iron deficiency & thrombosis risk) except in cases of Hyperviscosity syndrome =>Hyperviscosity Syndrome * phlebotomy is indicated in symptomatic hyperviscosity (blurred vision, headache, lethargy, seizures, altered mental status). * Hct usually >65%. * Management: * Emergent phlebotomy → target Hct <60%. * Replace equivalent volume with isotonic fluid. * Address underlying cause, consider pulmonary vasodilators judiciously.

Question 28

Management Principles in Cyanotic ACHD

Answer 28

I. Know the patient’s baseline SaO₂ → target return to baseline, not “normal” saturations. II. Avoid excessive oxygen → risk of pulmonary vasodilation, ↑ pulmonary blood flow, pulmonary edema. III. Use pulmonary vasodilators cautiously → can precipitate pulmonary edema. IV. Avoid drugs that ↓ SVR or ↑ PVR → worsens shunting & cyanosis. V. Avoid excessive sedation / hypercapnia → CO₂ retention ↑ PVR → worsens R→L shunting VI. IV access: always with 0.22-micron filters → prevent paradoxical emboli via R→L shunt.

Question 29

Mechanical Ventilation Considerations

Answer 29

=>Fontan physiology: * Blood flow is passive, dependent on negative intrathoracic pressure. * Positive pressure ventilation ↓ venous return, ↑ CVP, ↓ CO. *** If required → shortest inspiratory time, lowest possible PEEP.** =>RV dysfunction / Eisenmenger: * Same risks as above (RV preload dependent). * Use ventilation only when absolutely unavoidable.

Question 30

Pulmonary Hemorrhage in Eisenmenger Syndrome Platypnea–Orthodeoxia Syndrome

Answer 30

=>Pulmonary haemorrhage * Etiology: pulmonary infarction, in situ thrombosis, hyperviscosity. * Management: * Supportive care, avoid ventilation if possible. * Active bleeding → I**R for bronchial artery embolization. ** ⸻ =>Platypnea–Orthodeoxia Syndrome * Definition: Dyspnea & desaturation worse upright, improved supine. * **Mechanism: Often PFO + prominent Eustachian valve → IVC flow directed across PFO → cyanosis.** * Precipitants: Superimposed pulmonary insult ↑ PVR → worsens shunt. * Management: PFO closure indicated. * Other causes: Hepatopulmonary syndrome, pulmonary AVMs.

Question 31

Infective Endocarditis =>Epidemiology =>Risk factors =>Presentation =>Management

Answer 31

=>Epidemiology: Common in ACHD; major cause of morbidity and mortality. =>Risk factors: * Cyanosis * Abnormal native valves * Artificial prosthetic valves (mechanical or bioprosthetic) * Native/residual shunts * Prior endocarditis * Immunodeficiency =>Presentation: Often subtle and indolent * Febrile illness OR non-specific features (malaise, weight loss, rash, **hematuria)**. * Acute change in valve function (native or prosthetic) should trigger suspicion. =>Complication: **Brain abscess in cyanotic ACHD.** =>Management: * Early suspicion and blood cultures. * Echocardiography (TTE, often TEE needed). * Multidisciplinary care. * Prosthetic valve endocarditis → usually requires surgical replacement (exceptions exist depending on organism and status).

Question 32

Cerebrovascular Disease

Answer 32

1). Aneurysm rupture: * **Circle of Willis Berry aneurysm associated with coarctation of aorta. * Bleeding risk ↑ with hypertension.** 2). Cardioembolic stroke: * ↑ risk in ACHD, esp. with residual shunts or prosthetic valves. 3). Brain abscess: * Important complication of endocarditis in cyanotic ACHD. =>Management: * Multidisciplinary: neurovascular IR, neurology, ACHD cardiology. * Stroke/aneurysm management is generally similar to non-ACHD patients, with special attention to underlying cardiac anatomy/lesions.

Question 33

Prosthetic Valve Complications

Answer 33

=>Indication: Valve replacements are common in ACHD (mechanical or tissue). =>Evaluation in the critically ill: * Always assess prosthetic valves with echocardiography **(dysfunction, thrombosis, paravalvular leak, endocarditis)**. * Mechanical valve gradients (abnormal thresholds): ->Aortic: Peak gradient >36 mmHg → needs further Doppler assessment (velocity index, acceleration time, clinical correlation). ->Mitral: Mean gradient >6 mmHg → requires Doppler index, pressure half-time, correlation. * Causes: valve thrombosis, pathological regurgitation, high-output states, prosthesis–patient mismatch (esp. childhood valves later outgrown). * Valve thrombosis: -->Acute → feared, often requires emergent surgery. ->Thrombolysis: Alternative if surgery not possible. ->Slow infusion, small-dose regimens (6–25 hrs, often repeated). -> Contrasts with large bolus thrombolysis for PE/stroke.