Enhancement of Contrast Opacification for Echocardiographic Imaging of the Right Heart and Shunts
Condition: Bidirectional Cardiovascular Shunt
Study type: Interventional

Summary: 
      The study aims to answer whether the use of a mixture of blood and saline alone (limited air)
      provides the same degree of right-heart contrast enhancement as compared to the standard
      agitated saline (with air), during two types of echocardiograms.
    

Detailed description: 
      A cardiovascular shunt is an abnormality of the blood flow between the sides of the heart or
      between the systemic and pulmonary circulation. A right-to-left shunt diverts blood from the
      right side of the heart to the left side or from the pulmonary to the systemic circulation
      through an anomalous opening such as septal defect or patent ductus arteriosus. To visualize
      the shunt during an echocardiogram, agitated saline solution is injected intravenously to
      provide air microbubble contrast which opacifies (makes visible) the right heart chambers and
      is the standard used for the non-invasive detection of right to left intracardiac or
      intrapulmonary shunts. However, agitated saline has the potential risk of air microembolism.
      Although this type of adverse event is uncommon (<1% of strokes are related to air embolism),
      there have been reports in the literature of a number of small strokes/transient ischemic
      attacks following agitated saline injections at the time of echocardiographic studies. Mixing
      blood with saline substantially reduces the amount of air introduced, and this study will
      attempt to quantify the differences in the degree of contrast enhancement.

      100 patients scheduled for either Transesophageal Echocardiogram (TEE) or Transthoracic
      Echocardiogram (TTE) will be studied to determine the degree of contrast enhancement, when
      using a Saline/Air mixture versus a Saline/Blood mixture. Fifty participants of each type of
      echocardiography will be studied. The standard agitated saline mixture consists of 10
      milliliters of sterile saline and 0.5 milliliters of air agitated together in a syringe prior
      to injection. The agitated Saline/Blood mixture consists of 9 milliliters of sterile saline
      and 0.5 - 1 milliliter of blood and agitated together in a syringe prior to injection.

      All study participants will complete the routine clinical echocardiography (either a TEE or a
      TTE) with peripheral injection of agitated Saline/Air mixture, via an intravenous (IV)
      cannula attached to a three way stop cock. Blood removed from the patient will be withdrawn
      through the IV into a syringe and agitated with saline and then re-injected into the patient
      through the same tubing. After completion of the standard clinical imaging for shunt, the
      Saline/Blood mixture will be infused and an image obtained for comparison.

      For each study, digital images will be stored and an Investigator who does not know which
      treatment arm/mixture was used for a given image, will subsequently rate image quality and
      assign an image score using a semi-quantitative scale: 0 = poor/no right atrial
      opacification, 1 = average right atrial opacification, 2 = good right atrial opacification.
      After all images are analyzed, the scores will be compared for both TEE and TTE studies.
    

Intervention name(s): Transesophageal Echocardiogram (TEE); Transthoracic Echocardiogram (TTE); Saline/Air Mixture; Saline/Blood Mixture
Intervention type(s): Procedure; Procedure; Other; Other
Intervention description(s): Transesophageal echocardiography (TEE) is a test that produces pictures of the heart. TEE uses high-frequency sound waves (ultrasound) to make detailed pictures of the heart and the arteries that lead to and from it. Unlike a standard echocardiogram, the echo transducer that produces the sound waves for TEE is attached to a thin tube that passes through the mouth, down the throat and into the esophagus. Because the esophagus is so close to the upper chambers of the heart, very clear images of those heart structures and valves can be obtained.; An echocardiogram is a type of ultrasound test that uses high-pitched sound waves that are sent through a device called a transducer. The device picks up echoes of the sound waves as they bounce off the different parts of the heart. These echoes are turned into moving pictures of the heart that can be seen on a video screen.
Transthoracic echocardiogram (TTE) is the most common type of echocardiogram. Views of the heart are obtained by moving the transducer to different locations on the chest or abdominal wall.; The Saline/Air mixture consists of 10 milliliters of sterile saline and 0.5 milliliters of air agitated together in a syringe prior to injection.; The Saline/Blood mixture consists of 9 milliliters of sterile saline and 0.5 - 1.0 milliliters of blood agitated together in a syringe prior to injection.
Allocation: Non-Randomized
Intervention model: Parallel Assignment
Masking: Single (Outcomes Assessor)
Primary purpose: Diagnostic
Keywords: Shunt; Echocardiogram