VSD: Eisenmenger Effects

Eisenmengers syndrome (ES) is an advanced form of pulmonary arterial hypertension (PAH) that is associated with congenital heart defects (CHD).  A number of congenital heart defects can increase the flow and blood pressure in the pulmonary arterial vasculature. The cardiac defects most associated with ES are ventricular septal defects (VSDs), atrial septal defects (ASDs), atrioventricular septal defects, and patent ductus arteriosus. Early surgical correction of CHD has reduced the incidence of ES, but once PAH has developed surgical correction is contraindicated.

Begnetti and Galie' describe the pathophysiology of pulmonary artery hypertension associated with the afore mentioned forms of CHD .  The disease model begins with:

1. An uncorrected left-to-right shunt that increases pulmonary artery pressure and blood flow.
2. Increased blood flow causes shear stress on the endothelium and circumfrential stretch of the walls of the pulmonary arteries.
3. Endothelial stress injury leads to vascular remodeling characterized by inflammation, intimal proliferation of smooth muscle, deposition of extracellular matrix and intravascular thrombosis.
4. Smooth muscle proliferation increases pulmonary arteriole wall thickness, decreases lumen diameter and the extracellular matrix decreases compliance.
5. Narrowing lumen and stiffening of the vessel walls increase pulmonary vascular resistance (PVR).
6. Increased PVR raises the central venous and right heart pressures leading to right ventricular hypertrophy and shunt reversal.
7. The now right-to-left shunt reduces systemic arterial O² saturation and characterizes ES (Vongpatanasin. 1998)

Symptoms of ES differ with the type of CHD and with age.  Patients with uncorrected atrial septal defects (ASD) may not develop symptoms until 20 to 40 years of age (Beerman 2020). While patients with VSD, patent ductus arteriosus or more complex defects can develop symptoms as early as age 2 years (Frank 2015).

• Pulmonary hypertension - elevated blood pressure in the pre-capillary blood vessels of the lungs (pulmonary hypertension )
  
  • Shortness of breath
  • Fatigue
  • Lethargy
  • Exercise intolerance
  • Syncope
  • Cyanosis
• Right heart failure
  • Exertional dyspnea
  • Orthopnea
  • Paroxysmal dyspnea
  • Edema
  • Ascities
  • Hepatomegaly
  • Jugular distention
    

Eingelfriet et al. (2007) performed a 5-year follow-up study on a cohort of 1877 patients with atrial septal defect (ASD) n= 896, ventricular septal defect (VSD) n= 710.  They found 15 cases of ES in the ASD group. The VSD group had 83 cases of ES.  Pulmonary arterial hypertension was present in 34% of patients with an open ASD and 28% of patients with an open VSD. Patients with PAH had an eightfold increased probability of functional limitations, with a further sixfold increase when ES was present.

Treatment

Curative treatment for Eisenmenger Syndrome requires heart-lung transplant.

Palliative medical treatment focuses on managing the symptoms and complications

• pulmonary vasodilation
  • prostacyclin analogs: treprostinil, epoprostenol
  • endothelin antagonist: bosentan
  • nitric oxide enhancers sildenafil
• supplemental O²
• Phlebotomy in the event of erythrocytosis with hyperviscosity in response to chronic hypoxia (Oechslin 2010)
• Antithrobotic drugs
• Endocarditis prophylaxis before dental or surgical procedures that are likely to cause bacteremia.(Beerman 2020)

Instant Feedback: What direction is the shunt in an Eisenmenger effect:

References

Beghetti, M., & Galiè, N. (2009). Eisenmenger syndrome a clinical perspective in a new therapeutic era of pulmonary arterial hypertension. Journal of the American College of Cardiology, 53(9), 733–740. https://doi.org/10.1016/j.jacc.2008.11.025

Beerman, L. B. (2022, April 18). Eisenmenger syndrome - Pediatrics. Merck Manuals Professional Edition. Retrieved May 1, 2022, from https://www.merckmanuals.com/professional/pediatrics/congenital-cardiovascular-anomalies/eisenmenger-syndrome

Frank, D. B., & Hanna, B. D. (2015). Pulmonary arterial hypertension associated with congenital heart disease and Eisenmenger syndrome: current practice in pediatrics. Minerva pediatrica, 67(2), 169–185.

Oechslin, E., Mebus, S., Schulze-Neick, I., Niwa, K., Trindade, P. T., Eicken, A., Hager, A., Lang, I., Hess, J., & Kaemmerer, H. (2010). The Adult Patient with Eisenmenger Syndrome: A Medical Update after Dana Point Part III: Specific Management and Surgical Aspects. Current cardiology reviews, 6(4), 363–372. https://doi.org/10.2174/157340310793566127

van Vonderen, J. J., Roest, A. A., Siew, M. L., Walther, F. J., Hooper, S. B., & te Pas, A. B. (2014). Measuring physiological changes during the transition to life after birth. Neonatology, 105(3), 230–242. https://doi.org/10.1159/000356704

Vongpatanasin, W., Brickner, M. E., Hillis, L. D., & Lange, R. A. (1998). The Eisenmenger syndrome in adults. Annals of internal medicine, 128(9), 745–755. https://doi.org/10.7326/0003-4819-128-9-199805010-00008