Replies to This Discussion

Permalink Reply by Greggory DeVore MD on August 20, 2010 at 12:29pm

The reason for the "technically feasible" is because the outflow tracts cannot be obtained in all examinations. However, if the outflow tracts are not visualized, the examiner should state why and offer options for further evaluation. In my practice I have the patient return at no charge to examine the outflow tracts. This may happen in less than 1% of patients. If the examiner does not have the experience to identify the outflow tracts, then the patient should be given the option of being referred to someone who can. I have recently reviewed two cases in which the physician is being sued for missing transposition. The images and clips were classic for this malformation but the pathology was missed.

Permalink Reply by Lisa M. Allen on August 20, 2010 at 4:52pm

Dr. DeVore,

So, do you support the AIUM changing the guidelines and expectations for the practice of obstetric sonography? If you can get these additional views in your practice 99% of the time, don't you believe that other facilities could get similar results? I know we do.

As a statement to the community:

I believe, that if the outflow tract views were added, just like any other part of the anatomy, if you don't get it, you report as so and usually recommend a follow-up. In any given anatomy scan there is the potential that a part of the fetal anatomy may not be visulaized due to the technical limitations (maternal obesity, oligohydramnios, polyhydramnios, fetal lie, the presence of anomalies, etc) and there is no "technically feasible" statement associated with any other part of the anatomy in the guidelines. I feel very strongly, as many others do, that the guidelines need to be changed to require the outflow tracts. Obviously, this should also be an expectation for AIUM accreditation. Ultrasound practices would need to "raise the bar" if they want to become accredited. I feel that most AIUM accredited facilities are already doing this. This would be the push that the obstetrical sonography community needs to improve our detection rates for congenital heart disease. Over the past several years that I have attended the AIUM annual conference, multiple talks have emphasized and demonstrated the ease with which the outflow tracts can be obtained and have taught techniques such as the "sweep" method ( I believe that was your talk!!!). As a clinical instructor for an ultrasound program, I know all of the sonography students are taught how to get the outflow tracts. I have spoken with other accredited ultrasound programs and the same goes for them. If there are examiners out there that do not have the experience to obtain the outflow tracts, then they simply need to get some additional training/education. There are so many resources out there to achieve this. In my opinion, we have a responsibility to our patients to make this change. I am curious how other members of the community feel about this issue.

Permalink Reply by Judy Jones on June 5, 2011 at 10:42pm

I am a little late getting in on this discussion but perhaps it may get resurrected.  I strongly agree with Lisa Allen's comments.  If the guidelines say "technically feasible" this is essentially giving centers the option of saying "it was not technically feasible" to get the outflow tracts.  Alternately, if the outflow tracts were added as "required" , and if the center could not image them on the first scan, the patient would need to come back for another visit until the outflow tracts were visualized or the patient should be referred to a fetal echo center.  In my experience, if one is having difficulty visualizing the outflow tracts, they are often abnormal, which is even more reason to obtain the images and not sign off as a normal heart until they are seen.

Permalink Reply by Lisa M. Allen on June 6, 2011 at 7:14pm

Thanks Judy,

 

The way I look at it, we do not simply evaluate and image the fetal brain (which is also a very complex and vital organ) in just one plane, for instance, the transthalamic view for the measurement of the BPD and HC. According to AIUM guidelines for a routine obstetric anatomy scan, we are required to image and document the falx, thalamus and CSP at the level of the BPD, the cerebellum, cisterna magna, choroid plexus, and cerebral lateral ventricles. These structures are located at different levels and require knowledge of the intracranial structures, their relationship to each other, and their development. 

If just a 4-chamber view is required in a two-dimensional imaging plane, it is simply not sufficient enough to evaluate the cardiac structure and function, and by no means could we rule-out congenital heart disease based on this view alone. Personally, I would like to see additional views added to the guidelines for a routine obstetric exam, just like the multiple views of the brain. At a minimum, the 4-chamber view, LVOT, RVOT, 3VV, and perhaps the ductal arch. High hopes?!!! Here's hoping! Also, just because we are not required to obtain these views, that does not mean that we can't include these views in the unit specific protocols of our practices to improve the detection rate of congenital heart disease.

 

Lisa

Judy Jones said:

I am a little late getting in on this discussion but perhaps it may get resurrected.  I strongly agree with Lisa Allen's comments.  If the guidelines say "technically feasible" this is essentially giving centers the option of saying "it was not technically feasible" to get the outflow tracts.  Alternately, if the outflow tracts were added as "required" , and if the center could not image them on the first scan, the patient would need to come back for another visit until the outflow tracts were visualized or the patient should be referred to a fetal echo center.  In my experience, if one is having difficulty visualizing the outflow tracts, they are often abnormal, which is even more reason to obtain the images and not sign off as a normal heart until they are seen.

Permalink Reply by Mark Sklansky on June 25, 2011 at 10:21am

It has become increasingly clear that those cardiac defects for whom prenatal detection has the greatest impact on outcome are those defects that have abnormal outflow tracts and, frequently, normal four-chamber views. These defects, predominantly ductal-dependent lesions, include transposition of the great arteries, tetralogy of Fallot, double outlet right ventricle, truncus arteriosus, aortic stenosis, pulmonary stenosis/atresia, and others...We know that outflow tracts can be obtained routinely, albeit commonly with greater difficulty than the four-chamber view.  For these reasons, I strongly agree with the notion that we should "raise the bar" for the cardiac imaging required in low risk pregnancies at the time of the second trimester anatomic survey, and revise the most current set of guidelines that continue to use the "when technically feasible" and "an attempt may be made" escape clauses. For our patients' sake, raising the bar is the right thing to do.

 

For those who may be interested, I have attached our paper discussing the superiority of the outflow tracts over the four chamber view for detecting ductal-dependent forms of CHD.

Attachments:

• superioritypaper.pdf, 748 KB