Ventricular Septal Defects

Introduction

¨VSDs are common congenital abnormalities in children

¨Less common in adults due to spontaneous closure of most VSDs

¨Majority present as isolated defect

¨Can be an acquired condition secondary to acute MI or chest wall trauma

Complicating Factors

¨Subpulmonary stenosis

¨Pulmonary Hypertension

¨Aortic Regurgitation

Types of Ventricular Septal Defects

¨1 – Infundibular

¨2 – Membranous

¨3 – Inlet Defect

¨4 – Muscular Defect

Classification

¨Small or Restrictive

¡Orifice dimension less than or equal to 25% of aortic annulus diameter

¡Small left-to-right shunts, no left ventricular volume overload or pulmonary hypertension

¨Moderate

¡Measure more than 25% but less than 75% of aortic annulus diameter

¡Mild to moderate volume overload of pulmonary arteries, left atrium, and left ventricle

¡No (or mild) pulmonary hypertension

¨Large

¡Diameter measuring more than or equal 75% of aortic annulus

¡Large left-to-right shunts with left ventricular volume overload

¡Can cause significant pulmonary hypertension

Eisenmenger Syndrome

¨Progressive pulmonary hypertension , the right ventricular pressure can reach systemic levels leading to reversal of the shunt so that it is directed right-to-left with resultant hypoxemia and cyanosis

¨Elevated right ventricular and right atrial pressures cause right hypertrophy and right atrial enlargement

Natural History

¨Restrictive Defect

¡Small left to right shunt

¡Generally asymptomatic

¡Can see aortic regurgitation in adulthood with low risk of endocarditis

¨Moderate Defect

¡May remain asymptomatic; may develop mild heart failure in childhood

¡Heart failure resolves with medical therapy, and with time the VSD gets smaller (absolutely or relatively)

¨Large Defect

¡Early large left-to-right shunting with development of heart failure in infancy

¡In rare cases, presentation of Eisenmenger syndrome occurs sometime during late childhood to early adulthood

¡The right-to-left shunt causes cyanosis

Echocardiography

¨Detection rate: 88-95%

¨Most sensitive for VSD > 5 mm and those located in membranous, inlet, or infundibular system

¨Can determine presence and degree of shunting

Indications for Intervention

¨Pulmonary to systemic flow (Qp/Qs) > 2 and clinical evidence of left ventricular volume overload

¨History of infective endocarditis

¨Net left-to-right shunting with a Qp/Qs > 1.5 with pulmonary artery pressure less than two thirds of systemic pressure and pulmonary vascular resistance less than two-thirds of systemic vascular resistance.

¨Net left-to-right shunting with a Qp/Qs > 1.5 in the presence of left ventricular systolic or diastolic dysfunction or failure

Contraindications for Intervention

¨Severe, irreversible pulmonary artery hypertension

Summary

¨Thorough clinical, echocardiographic, and occasionally, invasive hemodynamic catheter evaluation are important in the assessment of VSD patients

¨These data can help determine the most appropriate timing of surgical or percutaneous