Retrospective Pulmonary Valve Replacement Imaging
Condition: Congenital Heart Disease
MeSH terms: Heart Diseases; Heart Defects, Congenital
Study type: Observational

Summary: 
      This is a retrospective chart review examining children and adults with history of Tetralogy
      of Fallot or pulmonary stenosis who have undergone subsequent pulmonary valve replacement.
      The primary interest of the study is to analyze the routine pre- and post-operative imaging
      studies.
    

Detailed description: 
      Congenital heart defects having a component of pulmonary stenosis (narrowing) are often
      palliated in childhood by disrupting the pulmonary valve. This arrangement can provide an
      excellent quality of life as these children grow and enter young adulthood. Unfortunately,
      the pulmonary insufficiency that is created by disrupting the pulmonary valve results in
      volume overload of the right heart. This may eventually lead to right ventricular dilation
      and irreversible right heart failure. In addition, volume load of the right heart may affect
      the inter-ventricular septum and left heart function as well. Placement of a competent
      pulmonary valve at a subsequent operation, hopefully at a time without the replacement valve
      size constraints present at the initial operation, is a means to eliminate the volume
      overload and prevent these further sequelae.

      Unfortunately, the optimal timing for subsequent pulmonary valve replacement is
      controversial. One of the currently used indications for valve replacement includes a right
      ventricular to left ventricular volume ratio greater than two. However, determining the
      boundaries of the right ventricle by echocardiography and magnetic resonance imaging is
      difficult in the absence of a pulmonary valve. The boundaries are determined by an arbitrary
      estimation of where the pulmonary valve should be. Other potential indicators for pulmonary
      valve replacement may be right ventricular area and right ventricular strain, determined by
      echocardiography. These measurements are not affected by the absence of the pulmonary valve.
      They may provide better markers for impending right ventricular failure and a simpler means
      to follow serial improvement following valve replacement.

      While the emphasis after pulmonary valve disruption typically lies on the right ventricle,
      there is evidence that the left ventricle may become impaired as well. Volume load on the
      right ventricle causes bowing of the inter-ventricular septum and affects left ventricular
      function. Echocardiographic imaging of the left ventricle may also be important to follow
      serial improvement of the left heart following pulmonary valve replacement.

      All charts reviewed will be of patients who had their surgery at Children's Healthcare of
      Atlanta or Emory University Hospital between January 1, 1994 and December 31, 2006. We will
      review approximately 125 patients' charts for patients between the ages of 1 and 65 years of
      age who have required pulmonary valve replacement.
    

Observational model: Case-Control
Time perspective: Retrospective
Sampling method: Non-Probability Sample
Study population: 
        This is a retrospective chart review examining children and adults with history of
        Tetralogy of Fallot or pulmonary stenosis who have undergone subsequent pulmonary valve
        replacement. The primary interest of the study is to analyze the routine pre- and
        post-operative imaging studies. All charts reviewed will be of patients who had their
        surgery at Children's Healthcare of Atlanta or Emory University Hospital between January 1,
        1994 and May 1, 2008. We will review approximately 200 patients' charts for patients
        between the ages of 1 and 65 years of age who have required pulmonary valve replacement.
      
Keywords: Pulmonary Stenosis; Right Ventricular Dilation; Right Heart Failure; Imaging; Tetralogy of Fallot