Pulmonary Hypertension and the D-sign on Ultrasound

A 31 y.o. female patient, with a history of Pulmonary Hypertension, Vasovagal Syncope, Dyspnea On Exertion, and Chronic Systolic Right Heart Failure, was admitted for Right Heart Catheterization secondary to Pulmonary Hypertension. The symptoms in this patient included: chronic cough, bilateral lower extremities edema, orthopnea, dyspnea, chest pain, dizziness, tachycardia, hoarseness, and diaphoresis.

We performed a bedside ultrasound looking from right ventricle strain. The image above shows a parasternal short-axis view of the heart. We saw the “D-sign” which is formed when the inter-ventricular septum is flattened during diastole and forms D-shaped left ventricle. This is a sign of right ventricular enlargement.

Assessment of the right ventricle size is part of a focused bedside heart ultrasound. A rule of thumb is that a right ventricle should be about ⅔ of the size of the left ventricle. If the right ventricle is the same size as the left ventricle, the right ventricle is moderately dilated. If the right ventricle is bigger than the left ventricle, the right ventricle is severely dilated. Even though we used a parasternal short-axis view, a 4-chambers apical view could also be used to assess right ventricular size.

Right ventricle size assessment is also used as a part of the workup in a patient with suspected Pulmonary Embolism. Weekes et al. showed that using echocardiography to detect right ventricular strain in the setting of PE has a sensitivity of 100% and specificity of 99%. This shows the accuracy of the bedside ultrasound to detect the right ventricular dysfunction.

Weekes et al. also evaluated the agreement between different observers over right ventricular dysfunction. Two emergency physicians and two cardiologists evaluated the images. There was an 83.9% agreement on right ventricular enlargement, 74.2% agreement on RV dysfunction and 71% agreement on the septal deviation. They concluded that the “Agreement was substantial for both severe RV enlargement and RV systolic dysfunction and moderate for septal deviation.” They used the following criteria to determine right ventricular dysfunction: “RV enlargement was present, with a right-to-left ventricular basal diameter ratio of 1.0 or higher and blunting of the apex of the RV in 2 or more different windows; RV systolic dysfunction was present if the tricuspid annulus moved toward the apex 10 mm or less and there was RV free wall hypokinesis; and septal deviation was present with any flattening or deviation of the ventricular septum toward the left ventricle.”

-Hector Almanzar-Ramos, MS4

References

• https://www.123sonography.com/ebook/how-assess-pulmonary-hypertension
• SonoSim Modules: Cardiology. https://sonosim.ttlms.com
• Weekes AJ, Oh L, Thacker G, Johnson AK, Runyon M, Rose G, Johnson T, Templin M, Norton HJ. Interobserver and Intraobserver Agreement on Qualitative Assessments of Right Ventricular Dysfunction With Echocardiography in Patients With Pulmonary Embolism. J Ultrasound Med. 2016 Oct;35(10):2113-20. doi: 10.7863/ultra.15.11007. Epub 2016 Aug 8. PubMed PMID: 27503757.
• Weekes AJ, Thacker G, Troha D, Johnson AK, Chanler-Berat J, Norton HJ, Runyon M. Diagnostic Accuracy of Right Ventricular Dysfunction Markers in Normotensive Emergency Department Patients With Acute Pulmonary Embolism. Ann Emerg Med. 2016 Sep;68(3):277-91. doi: 10.1016/j.annemergmed.2016.01.027. Epub 2016 Mar 11. PubMed PMID: 26973178

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