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McConnell’s Sign in Acute Pulmonary Embolism

Lau, Gary, MBChB, FRCA*; Ther, Gabor, MD, DESA*; Swanevelder, Justiaan, MBChB, FRCA, FCA (SA), MMED (Anes)

doi: 10.1213/ANE.0b013e31828a4b38
Cardiovascular Anesthesiology: Echo Didactics & Rounds
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Published ahead of print March 14, 2013

From the *Department of Anaesthesia, Glenfield Hospital, Leicester, United Kingdom; and Department of Anaesthesia, Groote Schuur Hospital, University of Cape Town Medical School, Cape Town, South Africa.

Accepted for publication October 23, 2012.

Published ahead of print March 14, 2013

Patient Consent Statement: Consent for publication of this case has been granted by the patient.

Funding: None.

The authors declare no conflicts of interest.

Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's Web site (www.anesthesia-analgesia.org).

Reprints will not be available from the authors.

Address correspondence to Gary Lau, MBChB, FRCA, Department of Anaesthesia, Glenfield Hospital, Groby Road, Leicester, LE3 9QP, United Kingdom. Address e-mail to gary.lau@uhl-tr.nhs.uk.

A 52-year-old woman presented with right calf swelling, chest pain, and shortness of breath. A computed tomography pulmonary angiography was performed, which demonstrated a massive pulmonary saddle embolus. She was transferred to our institution for an emergency surgical pulmonary embolectomy. After induction of anesthesia, a transesophageal echocardiography probe was inserted. The midesophageal ascending aorta short-axis view demonstrated a mass in the right pulmonary artery (PA) that occupied approximately two thirds of the vessel (Video 1, see Supplemental Digital Content 1, http://links.lww.com/AA/A522), and demonstrated a filling defect on color-flow Doppler (Fig. 1). There was no obvious mass in the main PA, and the left PA was not clearly visible. These findings suggested that the embolus had migrated distally. There were no further emboli identified in the inferior vena cava, the right atrium, or the right ventricle (RV).

Figure 1

Figure 1

The right atrium was severely enlarged, with the interatrial septum bulging into the left atrium throughout the entire cardiac cycle (Fig. 2). The RV systolic function was severely depressed. McConnell’s sign, with a hypokinetic midpapillary free wall and preserved apical contractility, was observed (Video 2, see Supplemental Digital Content 2, http://links.lww.com/AA/A523). The tricuspid annulus was dilated with moderate–severe tricuspid regurgitation. There was severe PA hypertension with an estimated RV systolic pressure of 64 mm Hg (maximum pressure gradient of the tricuspid regurgitation jet 50 mm Hg + central venous pressure 14 mm Hg). The left ventricle was underfilled with good systolic function. It had a “D-shaped” appearance with a flattened interventricular septum during the entire cardiac cycle, with paradoxical septal motion during late systole.

Figure 2

Figure 2

After sternotomy, the surgeon performed a longitudinal arteriotomy on the main PA and removed 2 large emboli from each of the right and left PAs. The patient was discharged from intensive care on the third postoperative day.

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DISCUSSION

Diagnosis of acute pulmonary embolism (PE) can be difficult because the clinical presentation can mimic other pulmonary or cardiac disorders. The first-line diagnostic imaging test is the computed tomography pulmonary angiography. Although echocardiography may visualize the pulmonary thrombus,1,2 its use is not recommended as a primary diagnostic modality for patients with suspected PE who are hemodynamically unstable.3 It has been demonstrated that the thrombus detection rate with transesophageal echocardiography is >50% in patients with suspected PE.4 In many clinical cases, only indirect signs of PE are present (Table 1).

Table 1

Table 1

Echocardiography is a useful adjunct in patients with hemodynamic instability to exclude other potential cardiac diseases such as RV infarction, valvular disease, and tamponade (Table 2). In addition, in patients with a suspected PE, echocardiography can assess its hemodynamic consequences and may be used to indicate the need for aggressive thrombolytic or surgical therapy.

Table 2

Table 2

The sudden occlusion of large portions of the pulmonary vascular bed results in an acute pressure overload on the RV. A distinct regional pattern of RV dysfunction may be noted, with akinesia of the midfree wall, and apparent normal motion at the apex. This characteristic echocardiographic finding has been described as “McConnell’s sign,” and 3 mechanisms have been proposed to explain these findings.5

First, in acute PE, apical sparing may be an illusion. Longitudinal velocity vector imaging demonstrated that there is a significant decrease in RV strain and RV apical deformation,6 and the appearance of preserved wall motion at the RV apex may occur due to the tethering of the dilated RV apex to a hypercontractile left ventricle. Second, the RV may assume a more spherical shape to equalize regional wall stress when subjected to an abrupt increase in afterload.5 Finally, there may be localized ischemia of the RV free wall as a result of increased wall stress.5 However, McConnell’s sign requires a significant degree of pulmonary perfusion obstruction before these echocardiographic findings become apparent. In addition, this pattern of RV dysfunction can be observed in cases of RV infarction and thus, cannot be considered a specific marker for the diagnosis of acute PE.

Another indirect sign of acute PE is the “60/60 sign,” which may appear with smaller perfusion defects. The 60/60 sign is the finding of a PA acceleration time (AT) of <60 milliseconds with a maximal tricuspid regurgitant pressure gradient of <60 mm Hg. The maximum tricuspid regurgitant pressure gradient should not exceed 60 mm Hg, as this is the maximum output of a nonhypertrophied RV. The PA AT is defined as the interval between the onset of systolic PA flow and peak flow velocity (Fig. 3). It can be measured by pulsed-wave Doppler interrogation of the PA in the midesophageal ascending aorta short axis, the upper esophageal aortic arch long axis, or the transgastric RV inflow–outflow views, with the sample volume in the main PA. The AT decreases in PE because of increased PA impedance from proximal thrombi with only moderately increased PA pressures. This may be a more sensitive variable for diagnosing acute PE than McConnell’s sign in patients without underlying cardiorespiratory disease.7

Figure 3

Figure 3

Recognition of these echocardiographic findings associated with massive PE could help critical care physicians in early management decisions regarding thrombolysis or embolectomy.

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DISCLOSURES

Name: Gary Lau, MBChB, FRCA.

Contribution: This author helped prepare the manuscript.

Name: Gabor Ther, MD, DESA.

Contribution: This author helped prepare the manuscript.

Name: Justiaan Swanevelder, MBChB, FRCA, FCA (SA), MMED (Anes).

Contribution: This author helped prepare the manuscript.

Attestation: Justiaan Swanevelder approved the final manuscript.

This manuscript was handled by: Martin J. London, MD.

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REFERENCES

1. Allyn JW, Lennon PF, Siegle JH, Quinn RD, D’Ambra MN. The use of epicardial echocardiography as an adjunct to transesophageal echocardiography for the detection of pulmonary embolism. Anesth Analg. 2006;102:729–30
2. Brzezinski M, Corkey WB, Grichnik KP, Swaminathan M. Transesophageal echocardiography of pulmonary thrombus causing complete left pulmonary artery occlusion. Anesth Analg. 2005;101:639–40
3. Douglas PS, Garcia MJ, Haines DE, Lai WW, Manning WJ, Patel AR, Picard MH, Polk DM, Ragosta M, Ward RP, Weiner RB. ACCF/ASE/AHA/ASNC/HFSA/HRS/SCAI/SCCM/SCCT/SCMR 2011 appropriate use criteria for echocardiography. A report of the American College of Cardiology Foundation Appropriate Use Criteria Task Force, American Society of Echocardiography, American Heart Association, American Society of Nuclear Cardiology, Heart Failure Society of America, Heart Rhythm Society, Society for Cardiovascular Angiography and Interventions, Society of Critical Care Medicine, Society of Cardiovascular Computed Tomography, and Society for Cardiovascular Magnetic Resonance Endorsed by the American College of Chest Physicians. J Am Coll Cardiol. 2011;57:1126–66
4. Pruszczyk P, Torbicki A, Kuch-Wocial A, Szulc M, Pacho R. Diagnostic value of transoesophageal echocardiography in suspected haemodynamically significant pulmonary embolism. Heart. 2001;85:628–34
5. McConnell MV, Solomon SD, Rayan ME, Come PC, Goldhaber SZ, Lee RT. Regional right ventricular dysfunction detected by echocardiography in acute pulmonary embolism. Am J Cardiol. 1996;78:469–73
6. López-Candales A, Edelman K, Candales MD. Right ventricular apical contractility in acute pulmonary embolism: the McConnell sign revisited. Echocardiography. 2010;27:614–20
7. Kurzyna M, Torbicki A, Pruszczyk P, Burakowska B, Fijałkowska A, Kober J, Oniszh K, Kuca P, Tomkowski W, Burakowski J, Wawrzyńska L. Disturbed right ventricular ejection pattern as a new Doppler echocardiographic sign of acute pulmonary embolism. Am J Cardiol. 2002;90:507–11
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Clinician’s Key Teaching Points

By Martin J. London, MD, Nikolaos J. Skubas, MD, and Roman M. Sniecinski, MD

  • An acute pulmonary embolism (PE) can often lead to significant hemodynamic instability, which is typically the result of right heart strain. Although computed tomography pulmonary angiography is the preferred diagnostic method for PE, transesophageal echocardiography can often be used to first exclude other causes of right-sided hypotension, including right ventricular (RV) infarction, cardiac tamponade, and hypovolemia.
  • In this case of acute PE, the nonspecific signs of RV pressure overload (right atrial and RV enlargement, tricuspid regurgitation, and bowing of interatrial and interventricular septa to the left) were imaged together with McConnell’s sign, a hypokinetic RV free wall with normal contraction of the RV apex. Additionally, the authors were able to actually view the PE in the right main pulmonary artery, which, unlike the left main pulmonary artery, can usually be reliably imaged.
  • Although it is rare to actually visualize a PE with transesophageal echocardiography, indirect findings such as McConnell’s sign and the “60/60 sign” (pulmonary artery acceleration time <60 milliseconds with tricuspid regurgitation gradient <60 mm Hg) can help clinicians make a presumptive diagnosis and institute timely treatment.

Supplemental Digital Content

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