Ventricular septal defects

Ventricular septal defects (VSDs) can be differentiated to 1) Congenital and 2) Acquired

1) Congenital VSDs

Ventricular septal defects (VSDs) are the most common forms of acyanotic congenital heart disease accounting for 37% of congenital heart disease in children.

It is less common in adults due to spontaneous closure of most muscular VSDs during childhood.

The intraventricular septum is formed by the growth and fusion of 1) the muscular septum, 2) inferior endocardial cushion, and 3) the conal septum.

A defect in the development of any portion of the septum will result in a VSD.

A VSD may occur as a primary anomaly, with or without additional major associated cardiac defects.

It may also occur as a single component of a wide variety of intracardiac anomalies, including tetralogy of Fallot (TOF), complete atrioventricular (AV) canal defects, transposition of great arteries, and corrected transpositions.

‍There are four major types of VSDs: 

• perimembranous
• muscular
• outlet
• inlet VSDs

Image 1 Types of Congenital VSDs

https://pedecho.org/library/fetal/Fet-VSD

The spectrum of VSDs in adults includes the following hemodynamic and clinical types:

• Small restrictive VSDs with small left-to-right shunts (pulmonary to systemic flow ratio [Qp:Qs] <1.5:1); this type is generally associated with no symptoms and no pulmonary hypertension (PH). 

• Moderately restrictive VSDs with moderate shunts (Qp:Qs ≥1.5:1 and <2:1) that have not undergone closure often cause mild to moderate PH, and/or left heart volume overload, which may cause symptoms. 

• Large nonrestrictive unrepaired VSDs cause progressive pulmonary arterial hypertension. The left-to-right shunt declines and then reverses; the resultant right-to-left shunt causes hypoxemia and cyanosis (Eisenmenger syndrome).

A VSD should be suspected in a patient who presents with a characteristic murmur.

‍

2) Acquired VSDs

Ventricular septal rupture (VSR) is a rare (only 0.17 and 0.31% of patients with AMI), but lethal mechanical complication of acute myocardial infarction.

Implementation of PCI into standard therapeutic management of ACS has led to a decline in the incidence of VSR, but despite that, overall mortality of patients who develop VSR remains high (41-80%).

Ventricular septal defect usually occurs 3-5 days after AMI, but can occur much sooner in a matter of hours (median at 16 h).

Risk factors for VSR include older age, female sex, prior stroke, chronic kidney disease, and CHF.

Upon clinical presentation, VSR is more likely to develop in patients with ST segment elevation, initial positive cardiac biomarkers, cardiogenic shock, cardiac arrest, higher Killip class, and longer times to first balloon inflation or thrombolytic administration.

Rupture can occur at any anatomic location of the septum after a transmural infarction. Anterior infarctions are more likely to cause apical defects and inferior or lateral infarctions are more likely to cause basal defects at the junction of the septum and the posterior wall.

Every patient with AMI should be examined for mechanical complications. The easiest way is to listen for a characteristic harsh, holo-systolic murmur over the precordium.

‍The symptoms may vary from complete hemodynamic stability to circulatory collapse depending on the size of the defect.

‍

Management of MI related VSDs

a) Surgery
  - Definitive surgery remains the treatment of choice, but is still a challenging operation associated with high early mortality (around 42%).

    - Acute infarcted myocardium is weak and friable, and sutures hold poorly which leads to an increased risk of tearing and recurrent septal defects. For the.                repair to be successful, the surgeon must perform a debridement of infarcted tissue back to healthy myocardium (even if it involves enlarging the defect), and        avoiding tension on the repair by using an appropriately sized patch.

   - The time between VSR detection and its repair is a determining factor in the survival or mortality of patients. Studies showed that earlier repair and operation in VSR         patients increases the risk of mortality. A delayed surgery (usually > 2-3 weeks), should be preferred, because of improved stability of the cardiac tissue as the         infarct evolves, allowing a more effective repair. Unfortunately, in a large number of patients, it is not possible to delay the operation since they are at risk of         severe heart failure and organ dysfunction.  

b) Percutaneous VSR closure
      - Percutaneous closure of VSR is an option for patients with significant risk for surgical repair, either as a definitive strategy, or as a bridge to surgery after initial           stabilization. For this to be successful the rupture must have favourable anatomy and an adequate tissue rim to secure the device.

c) IABP can be used as a treatment strategy for off-loading of a left ventricle in patients with ventricular septal defect. Position of IABP should be checked on X-ray on       a regular basis, as distal migration of the device might be observed.

‍

‍ECHO

The goals of ECHO in assessing VSDs preoperatively:

• Determine the location and size of the defect
• Determine relationships with nearby structures (ie. Aortic and pulmonary valves)
• Measurement of defect margins
• Hemodynamic assessment including flow direction (by color and spectral Doppler)
• Estimation of RV systolic pressure (TR jet velocities)
• Mean transseptal pressure gradient
• Evidence of hemodynamic load (LV enlargement, systolic septal flattening associated with RV pressure load, increased pulmonary blood flow)
• Biventricular function
• Associated lesions

Color Doppler transthoracic echocardiography (TTE) is the most valuable tool for diagnosis of VSD because of its high sensitivity, detecting up to 95% of VSDs, especially nonapical lesions larger than 5 mm.

The septum is a complex curved surface; traditionally careful assessment using multiple two-dimensional (2D) echocardiographic planes has been used to define the location and extension of defects.

‍

Perimembranous defects (aka paramembranous, membranous) 

Perimembranous defects are the most common type of VSDs and involve the membranous ventricular septum adjacent to aortic and tricuspid valves. 

These defects can be imaged from parasternal, apical, or subcostal views.

Located adjacent to the tricuspid valve, perimembranous VSD can be associated with tricuspid septal leaflet distortion with tricuspid regurgitation.

Accessory tissue or part of septal leaflet of tricuspid valve can partially or completely close the defect, referred to as “ventricular septal aneurysm”.

Occasionally blood from VSD can traverse through aneurysmal tissue across the tricuspid valve into the right atrium leading to LV to right atrial shunt.

About 10% of perimembranous defects are associated with AV prolapse due to close proximity with AV. It can be identified by right or noncoronary cusp protruding into the VSD best seen in parasternal long- and short-axis views. Due to importance in the development of aortic regurgitation, the presence of aortic cusp prolapse should be carefully reported. 

About 5% of perimembranous defects are associated with a subaortic ridge with or without subaortic obstruction. These are fibromuscular in origin and located at the inferior aspect of VSD commonly associated with septal aneurysm.

Video 1a  PSAX with colour Doppler shows perimembranous ventricular septal defect (approx. 4x6 mm) with left to right ventricle jet. 

Video 1b  PSAX view shows perimembranous ventricular septal defect/aneurysm, seen protruding to the left of aortic valve.

Video 1c A4C TTE view documenting permembranous VSD with L-R shunt

Video 1c  TEE assessment of the same patient with perimembranous VSD - aneurysm of the membranous part of the IVS, partly formed by septal cusp tissue of tricuspid valve. Defect with left to right shunt and diameter of 5mm is seen in the apical part of the aneurysm.

Video 1d TEE, aneurysm with defect of the membranous part of IVS, left to right shunt, colour Doppler of the jet 

Image 1e Maximal gradient over the VSD = 101 mmHg

Video 1f Angiography of the shunt, oxymetry proves the L-R shunt 1.4:1 (Qp= 6,9l/min vs. Qs= 4,9 l/min)

‍

Video 2a Perimembranous VSD with aneurysm, A5C view - aneurysm approx. 26x15x15 mm in size of the perimembranous part of the interventricular septum (IVS) is protruding into the RV.

Video 2b  Perimembranous VSD with aneurysm, A5C view with colour - note the flow across the defect in the IVS aneurysm, diameter approx. 4 mm with peak gradient across the defect measured at 105 mmHg.

Video 2c  Perimembranous VSD with aneurysm, PLAX view

Video 2d TEE in the same patient with Perimembranous VSD with aneurysm

Image 2e Maximal gradient over the VSD = 103 mmHg

‍

Apical VSD

Video 3 Apical VSD - Colour Doppler documenting tiny L-R shunt

Muscular VSD

Video 4a Muscular VSD - gap in the VSD as a congenital heart disease is appartent in the mid of the septum

Image 4b Size of the VSD in the same patient (7 mm)

‍

POST MYOCARDIAL INFARCTION RELATED VSDs

Video 5a Ventricular septal defect as a mechanical complication of acute myocardial infarction, A4C view - akinesis of the basal ⅓ of the inferior wall following the acute MI, hyperkinesis of other segments, hypertrophic septum (IVS 12mm). VSD in the basal part of the septum, opening to the LV has a diameter of 11mm.

Video 5b VSD as a mechanical complication of acute myocardial infarction, A4C with colour Doppler - note the left-to-right shunt as the blood flows from the LV through the VSD into RV.

Video 5c VSD post AIM in the same patient, subcostal view - this view shows the VSD propagates through the IVS and splits into two canals (7 and 4mm in width) and continues into the basal part of the inferior wall.

Image 5d Entrance into the VSD from the LV, diameter 13mm

Video 6a Large VSD document in the basal septum after subacute MI of inferior wall

Video 6b Colour Doppler over the large VSD

Image 6c Dize of the rupture (15 mm)

‍‍Video 7a Apical ventricular septal defect as a complication of anterior acute myocardial infarction, A4C view - aneurysm and akinesis of the apical ⅓ of the heart with a anteroseptal rupture of the IVS, diameter 6x9 mm. A left-to-right shunt jet is aimed into the apex of the right ventricle.

‍Video 7b Apical VSD resolved by surgical treatment, no residual jet is seen.

‍

References

1. Ventricular Septal Defects - Congenital Cardiac Anesthesia Society. Congenital Cardiac Anesthesia Society - Congenital Cardiac Anesthesia Society [online]. Copyright © 2020 The Congenital Cardiac Anesthesia Society [cit. 04.09.2021]. Dostupné z: https://ccasociety.org/education/echoimage/vsd-echo/
2. Tripathi RR. Ventricular Septal Defect: Echocardiography Evaluation. J Indian Acad Echocardiogr Cardiovasc Imaging [serial online] 2020 [cited 2021 Sep 4];4:260-6. Available from: https://www.jiaecho.org/text.asp?2020/4/3/260/303938
3. Ann Kavanaugh-McHugh, Warren J Manning, Susan B Yeon. Echocardiographic evaluation of ventricular septal defects. Available from: https://www.uptodate.com/contents/echocardiographic-evaluation-of-ventricular-septal-defects
4. Ventricular Septal Defects: Background, Anatomy, Pathophysiology. Diseases & Conditions - Medscape Reference [online]. Copyright © 1994 [cit. 04.09.2021]. Available from: https://emedicine.medscape.com/article/892980-overview
5. Naser M Ammash, Heidi M Connolly, Candice Silversides, Susan B Yeon.Clinical manifestations and diagnosis of ventricular septal defect in adults. Available from: https://www.uptodate.com/contents/clinical-manifestations-and-diagnosis-of-ventricular-septal-defect-in-adults
6. Brandon M. Jones, Samir R. Kapadia, Nicholas G. Smedira, Michael Robich, E. Murat Tuzcu, Venu Menon, Amar Krishnaswamy, Ventricular septal rupture complicating acute myocardial infarction: a contemporary review, European Heart Journal, Volume 35, Issue 31, 14 August 2014, Pages 2060–2068, https://doi.org/10.1093/eurheartj/ehu248
7. Urschel CW, Eber L, Forrester J, Matloff J, Carpenter R, Sonnenblick E. Alteration of mechanical performance of the ventricle by intraaortic balloon counterpulsation. Am J Cardiol. 1970 May;25(5):546-51. doi: 10.1016/0002-9149(70)90593-x. PMID: 5441342.
8. Intra-aortic Balloon Counterpulsation: Overview, Indications, Contraindications. Diseases & Conditions - Medscape Reference [online]. Accessible at: https://emedicine.medscape.com/article/1847715-overview
9. Shafiei I, Jannati F, Jannati M. Optimal Time Repair of Ventricular Septal Rupture Post Myocardial Infarction. J Saudi Heart Assoc. 2020 Jul 31;32(2):288-294. doi: 10.37616/2212-5043.1120. PMID: 33154931; PMCID: PMC7640570.
10. Mubarik A, Iqbal AM. Ventricular Septal Rupture. 2020 Apr 14. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2020 Jan–. PMID: 30521278