Case # 16: The Smoking Gun

A 32 year-old woman with history of pleurisy and systemic lupus erythematosus presented to the emergency department with three weeks of shortness of breath and pleuritic chest pain, acutely worse one day prior to arrival.

She flew into San Diego three days prior to her hospital presentation. She became dyspneic when walking from her hotel bed to the bathroom. On review of systems, she did endorse 3 weeks of right lower leg cramping. She denied fever/chills, cough, back pain, or history of blood clots. She was tachypneic and speaking in short phrases upon arrival.

Vitals: T: 98.3, HR: 130, BP: 142/88, RR: 24, SpO2 97% on RA

A bedside ultrasound ECHO and lower extremity scan was preformed.  What do you see?

 

ezgif.com-video-to-gif
RV strain gif
dvt gif 2

Answer and Learning Points

Answer

These ultrasound images show an apical 4 chamber and parasternal short view of the heart, as well as a right lower extremity DVT. The apical 4 chamber demonstrates right ventricular dilation with bowing of the septum into the left ventricle. The parasternal short illustrates “D sign” with right ventricular dilation and bowing/flattening of the interventricular septum leading to decreased left ventricular systolic function. Both views indicate right heart strain in the setting of likely pulmonary embolism. The right lower extremity showed a noncompressible right femoral vein, indicating DVT.

TPA was prepared and ready to give incase patient had worsening hemodynamic instability. She was fortuantley able to tolerate further imaging without HD compromise; CT angio confirmed the diagnosis of pulmonary embolism in bilateral main pulmonary arteries extending into all 5 lobes. Half dose TPA was administered and the patient was admitted to the ICU.

Learning Points

    • Identification of right ventricular dilatation on point-of-care echocardiography for the diagnosis of pulmonary embolism has a sensitivity of 50%, but a specificity of 98%1
    • Patients who present normotensive but have signs of cardiac dysfunction secondary to a PE are classified as submassive, and thrombolytic therapy should be considered2
    • When combining echocardiogram with lower extremity ultrasound, the sensitivity and specificity of cardiac US are 91% and 87%, respectively. Venous US shows a lower sensitivity 56%, but higher specificity 95% than cardiac. When cardiac and venous US are both positive the specificity increases to 100%, whereas when at least one was positive the sensitivity increased to 95.3
    • There is a broad differential of patients presenting to the emergency department with chest pain and shortness of breath. Point-of-care transthoracic cardiac ultrasound in the ED is an effective tool to promptly diagnose acute pulmonary embolism with right heart strain, and rapidly guide management.4,5 This patient with a history of lupus and pericarditis could have presented with cardiac tamponade, and ultrasound did show a small circumferential pericardial effusion, but did not show a collapsing right ventricle that would be expected in tamponade (instead, a dilated RV is seen).6
 

Author

Nicolas Kahl, MD. Emergency Medicine Resident. UCSD Department of Emergency Medicine.

Jessica Oswald, MD. Clinical Faculty, UCSD Department of Emergency Medicine. 

Sukhdeep Singh, MD. Clinical Faculty, UCSD Department of Emergency Medicine. Director of POCUS, El Centro Regional Medical Center.

References

  1. Dresden S, et al. Right Ventricular dilatation on bedside echocardiography performed by emergency physicians aids in diagnosis of pulmonary embolism. Ann Emerg Med; 2014 Jan; 63(1):16-24
  2. Malik Sonika et al. Advanced Management Options for Massive and Submassive Pulmonary Embolism. USC US Cardiology Review. 2016 Feb. 
  3. Nazerian P, et al.Diagnostic accuracy of focused cardiac and venous ultrasound examinations in patients with shock and suspected pulmonary embolism.Intern Emerg Med. 2018 Jun;13(4):567-574
  4. Fields JM, et al. Transthoracic Echocardiography for Diagnosing Pulmonary Embolism: A Systematic Review and Meta-Analysis.J Am Soc Echocardiogr. 2017
  5. Kahl N, et al. Point-of-care Ultrasound Diagnosis of Pulmonary Embolism with Thrombus in Transit.Clin Pract Cases Emerg Med. 2019 Feb; 3(1): 11–12.
  6. Singh, S., et al., Usefulness of right ventricular diastolic collapse in diagnosing cardiac tamponade and comparison to pulsus paradoxus.Am J Cardiol, 1986. 57(8): p. 652-6.

Case # 15: When Lines Go Wild

A 35 year old woman with sickle cell disease presented to the emergency department with localized swelling and pain near her port site. The pain started two days prior to arrival, when she was at an infusion center and her port was found to be inaccessible by the staff. She stated that the staff were unable to draw back any blood. She denied shortness of breath, chest pain, fever, or any other skin changes aside from the swelling.

Vitals: T: 97.8, HR: 64, BP: 144/80, RR: 16, Sat: 96% on RA

A bedside ultrasound ECHO was preformed to evaluate the distal tip of the port.  What do you see?

Answer and Learning Points

Answer

These ultrasound images show an apical 4 view of the heart. There is a hyperechoic mass in the right atrium that does not shadow, suggestive of a line thrombosis. A CT angio confirmed the diagnosis, showing a large clot adhered to the distal tip of the catheter.

Learning Points

    • Catheter-related complications are common and are the cause of significant morbidity and mortality for patients that have chronic indwelling lines. Symptomatic rates are reported to be 5% with asymptomatic rates increasing to nearly 20%(1).
    • Typical imaging beings with an upper extremity ultrasound. However, challenges arise as compression is unattainable when dealing with subclavian vessels(2). CT can improve the sensitivity and specificity(3).
    • In our case, a DVT ultrasound would not have been adequate, as the port is inserted over the subclavian vessel. However, a clot located in the heart can be easily detected on a cardiac echo. A CT angio was used to confirm there was a clot adhered to the line, but no pulmonary embolism.
    • Ultrasound can be used to evaluate for RV strain and at times may note RA thrombosis (such as in this case), clots in transit, and can be helpful in evaluating lines that extend into the right atrium/right ventricle.  

Ultrasound findings of clots on the cardiac echo:

Non-adhered clots will typically be floating/tumbling with cardiac motion. Since they are non-calcified, shadowing does not typically occur.

Right Atrial Thrombus
Dr. Scheels. The POCUS Atlas. http://www.thepocusatlas.com/

This can be difficulty to distingue from other masses, such as an atrial myxoma. However the correct clinical context is able to help.

Atrial Myxoma
Dr. Russell. The POCUS Atlas. http://www.thepocusatlas.com/

Using echo to check line placement/wire tips is not uncommon. Obtaining an apical 4 view as done in this case, one can evaluate the right atrium and right ventricle.


Dr. Ftacnikova et al. 3D ECHO 360. http://3decho360.com/cc19/

Author

Sukhdeep Singh, MD. Clinical Faculty, UCSD Department of Emergency Medicine. Director of POCUS, El Centro Regional Medical Center

References

  1. Verso M, Agnelli GJ. Venous thromboembolism associated with long-term use of central venous catheters in cancer patientsJ Clin Oncol 2003; 21: 3665–3675.
  2. Sartori M, Migliaccio L, Favaretto E, et al. Whole-Arm Ultrasound to Rule Out Suspected Upper-Extremity Deep Venous Thrombosis in Outpatients. JAMA Intern Med. 2015;175(7):1226–1227. doi:10.1001/jamainternmed.2015.1683
  3. Gita Yashwantrao Karande, Sandeep S. Hedgire, Yadiel Sanchez, Vinit Baliyan, Vishala Mishra, Suvranu Ganguli, Anand M. Prabhakar
    Cardiovasc Diagn Ther. 2016 Dec; 6(6): 493–507. doi: 10.21037/cdt.2016.12.06

Right ventricular dilatation on bedside echocardiography performed by emergency physicians aids in the diagnosis of pulmonary embolism

Background

Pulmonary embolism (PE) is a disease entity with a high mortality rate, ranging from 2.5-33%. Frequently, its diagnosis is delayed or frankly missed and often it is only discovered during autopsy. Around 66% of deaths occur during the first hour of presentation and 75% of deaths during the initial hospitalization. The mechanism of morbidity/mortality for PE is thought to be secondary to right ventricle (RV) outflow obstruction, leading to circulatory collapse. Delays in diagnosis have been linked to issues with imaging (wait times, schedules), contrast in the setting of renal impairment, and poor IV access.

In the emergency department, it is not only critical to identify patients with PE, but also to identify those who are at risk for decompensation and poor outcomes. This can be accomplished by evaluating for signs of RV dysfunction which has been associated with RV failure, hemodynamic collapse, and death. Previous studies have shown that right ventricular dysfunction has been found in 27-40% of normotensive patients with PE. Well studied markers of RV dysfunction include elevated biomarkers [1], specific ECG findings (RBBB, tachycardia, S1Q3T3, anterior TWI, ST elevation aVR, atrial fibrillation) [2], and RV dysfunction on echocardiography [3]. While biomarkers and ECG are readily available to emergency providers (EP), these are less specific for the diagnosis of PE and bedside echocardiography may prove to be more useful for evaluation of PE and RV dysfunction.

Right Ventricular Dilatation on Bedside Echocardiography Performed by Emergency Physicians Aids in the Diagnosis of Pulmonary Embolism

Clinical Question

Does evaluation for right ventricular dilation by emergency physicians using bedside echocardiography add diagnostic value in the evaluation for suspected pulmonary embolism? 

Methods & Study Design

  • Design
    • Prospective observational study
  • Population
    • Using a “convenience sample” population of patients who presented to the ED at Boston Medical Center from June 2009 – August 2011, with a moderate to high suspicion (pretest probability) of having a PE.  Wells score 2, those receiving PE imaging (CT, angio, V/Q scan), or those who came in with diagnosis of PE.
  • Exclusion criteria 
    • Non-english speakers
    • Prisoners
  • Intervention
    • Transthoracic echocardiography (blinded of confirmatory results) was performed by 4 ED docs, 1 with advanced training in cardiac sonography.  The other 3 had standard 1-month residency rotation in ultrasound and a minimum of 25 cardiac ultrasounds; plus, 10 hours hands-on and 10 hours image review with principal investigator.
    • Data collection
      • 3 views recorded: parasternal short & long axis, and apical 4-chamber, with primary measurement being qualitative assessment of RV size vs. LV size. Normal ratio (0.6:1)
        • Dilation defined as >1:1 RV:LV ratio
        • RV length and diameter or qualitative distension of RV apex adjacent to LV apex also assessed
      • They also recorded: RV function (nl vs. hypokinetic), paradoxical septal motion, and presence of McConnell’s sign.
      • All image reads were reviewed by the PI.
      • ED RAs then used chart review to compare findings to confirmatory imaging
        • PE was categorized as proximal vs distal
        • Disposition of patient was also documented 
  • Outcomes
    • Diagnostic characteristics
      • Sensitivity, specificity, PPV, NPV, positive and negative likelihood ratios
    • Presence of advanced signs of RV dysfunction
      • Right ventricular hypokinesis [qualitatively assessed as normal or hypokinetic], paradoxical septal motion, and McConnell’s sign

Results

    • Final analysis
      • 146 patients included in study
      • 126 with moderate pretest probability
      • 20 with high pretest probability
      • 126 with normal RV:LV ratio, 17 with increased RV:LV ratio
      • 30 had PE, of these 15 also had increased RV:LV ratio
    • Presence of RV dilation test characteristics
      • Sensitivity 50% (95% CI 32% to 68%)
      • Specificity 98% (95% CI 95% to 100%), a positive predictive value of 88%
      • Positive Predictive Value 88%  negative predictive value of 88%
      • Negative Predictive Value 88% (95% CI 83% to 94%).
      • Positive Likelihood Ratio 29 (95% CI 6.1% to 64%)
      • Negative Likelihood Ratio 0.51 (95% CI 0.4% to 0.7%)
      • Good observer agreement 96%, independent 100%

Strengths & Limitations

  • Strengths
    • Good concordance of sens/spec with prior study observations, although higher sensitivity
    • Good intra-observer agreement/reliability
  • Limitations
    • Single location, young population (less chronic diseases leading to RV changes)
    • Operator skill may not generalize to other physicians, other EDs.  PI was very experienced sonographer.
    • Convenience sample leading to possible selection bias.
    • Secondary outcomes under-powered.

Author's Conclusions

The authors conclude that right ventricular dilatation on bedside echocardiography may help emergency physicians rule in pulmonary embolism more rapidly by raising a provider’s index of suspicion before definitive testing. They also note that this evidence supports the concept that patients with a moderate to high pretest probability for pulmonary embolism and a bedside echocardiography result showing right ventricular dilatation should be considered for anticoagulation before definitive testing.

Lastly, they also comment on severity of PE, noting that patients with signs of advanced right ventricular dysfunction on bedside echocardiography (right ventricular dilatation with right ventricular hypokinesis, McConnell’ s sign, or paradoxical septal motion), tends to occur in patients with a larger clot burden who are more likely to be admitted to an ICU setting or have in hospital mortality (though this study was not powered appropriately for this analysis).

Our Conclusions

 We agree with the author's conclusions of this study that EP performed bedside echocardiography is a useful adjunct in the evaluation of suspected PE, both in identification of PE as well as risk stratification. We know that delays in diagnosis/treatment can lead to worse outcomes, however with the ability of EPs to perform bedside echocardiography and identify right ventricular dilation, this may reduce the time to both of these endpoints. It also seems reasonable that in patients who are moderate to high risk for PE, whom have evidence of right ventricular dilation on bedside echocardiography,  be empirically treated with anticoagulation prior to definitive imaging, with the caveat that they have no high bleed risk.

The Bottom Line

Emergency physician performed bedside echocardiography can be used reliably to increase provider's index of suspicion for PE in patients demonstrating RV dilation; however, given its poor sensitivity, it should not be used as a screening tool for PE.

Authors

This post was written by Hector Guerrero, MS4 at UCSD. It was reviewed by Michael Macias, MD, Ultrasound Fellow at UCSD.

References

    1. Weekes AJ, e. (2017). Diagnostic Accuracy of Right Ventricular Dysfunction Markers in Normotensive Emergency Department Patients With Acute Pulmonary Embolism. - PubMed - NCBI. Ncbi.nlm.nih.gov. Retrieved 25 September 2017, from https://www.ncbi.nlm.nih.gov/pubmed/26973178
    2. Shopp, J., Stewart, L., Emmett, T., & Kline, J. (2015). Findings From 12-lead Electrocardiography That Predict Circulatory Shock From Pulmonary Embolism: Systematic Review and Meta-analysis. Academic Emergency Medicine, 22(10), 1127-1137. doi:10.1111/acem.12769
    3. Dudzinski DM, e. (2017). Assessment of Right Ventricular Strain by Computed Tomography Versus Echocardiography in Acute Pulmonary Embolism. - PubMed - NCBI . Ncbi.nlm.nih.gov. Retrieved 25 September 2017, from https://www.ncbi.nlm.nih.gov/pubmed/27664798
    4. Dresden S, e. (2017). Right ventricular dilatation on bedside echocardiography performed by emergency physicians aids in the diagnosis of pulmonary embolism. - PubMed - NCBI . Ncbi.nlm.nih.gov. Retrieved 25 September 2017, from https://www.ncbi.nlm.nih.gov/pubmed/24075286

Case # 1: The Acutely Winded Traveler

A 65 year old female presents with shortness of breath after a return flight from the Gold Coast of Australia to the United States.

Vitals: HR 107 BP 110/80 RR 22 O2 95

RV+Strain_Mead

Answer and Learning Point

Answer

There is right ventricular dysfunction demonstrated as septal bowing appreciated on this parasternal short axis view. This is concerning for a pulmonary embolism in the setting of the provided clinical context.

Learning Point

Echocardiography can be a useful adjunct to laboratory markers (i.e. BNP and troponin) and CTA for evaluation of right heart strain in normotensive patients presenting with concern for pulmonary embolism.  While there is building evidence that many patients presenting with pulmonary embolism are safe for discharge [1] , those patients that have evidence of right ventricular dysfunction are at higher risk for morbidity and mortality and may also be candidates for more advanced therapies, other than simple anticoagulation, such as catheter directed thrombolysis.  The most up-to-date evidence supports that emergency physicians can accurately perform echocardiography at the bedside to risk stratify patients presenting with concern for pulmonary embolism. In a recent study by Weekes et al, emergency physicians (EP) performed goal directed echocardiography to assess for right ventricular dysfunction. If any of the following criteria below were present, a patient was considered positive by goal directed echocardiography for right ventricular dysfunction:

This study found the EP goal-directed echocardiography sensitivity and specificity for right ventricular dysfunction to be 100% (CI 87% to 100%) and 99% (95% CI 94% to 100%), respectively [2]. Our patient ended up having a saddle embolus and underwent catheter directed thrombolysis and did well.

References

  1. Aujesky D, e. (2017). Outpatient versus inpatient treatment for patients with acute pulmonary embolism: an international, open-label, randomised, non-inferiority trial. - PubMed - NCBI . Ncbi.nlm.nih.gov. Retrieved 8 July 2017, from https://www.ncbi.nlm.nih.gov/pubmed/21703676

  2. Weekes AJ, e. (2017). Diagnostic Accuracy of Right Ventricular Dysfunction Markers in Normotensive Emergency Department Patients With Acute Pulmonary Embolism. - PubMed - NCBI . Ncbi.nlm.nih.gov. Retrieved 8 July 2017, from https://www.ncbi.nlm.nih.gov/pubmed/?term=26973178