60/60 sign for Acute PE

Disturbed Right Ventricular Ejection Pattern as a New Doppler Echocardiographic Sign of Acute Pulmonary Embolism

Kurzyna. Am J Cardiology 2002;90:507-511

Clinical Question

  • In patients with suspected acute pulmonary embolism, do echo features of disturbed right ventricular ejection allow accurate diagnosis?

Background

  • In patients with acute pulmonary embolism (APE), right ventricular (RV) pressure overload often occurs which can be detected by echocardiography. In patients with pre-existing cardiorespiratory disease the presence of RV overload may be chronic
  • A retrospective study suggested that in patients with pre-existing pulmonary hypertension the 60/60 sign may be able to aid in the correct diagnosis of APE
  • This study investigated whether the 60/60 sign and McConnell’s sign are useful diagnostic tools in the assessment of suspected APE in patients with and without pre-existing cardiorespiratory disease

Design

  • Prospective observational diagnostic cohort
  • Consecutive patients
  • Not stated if assessors of test of interest were blinded to results of gold standard investigation
  • Statistical analysis
    • Differences between groups compared with Student’s t test or Mann’s U test
    • Differences between categorical variables assessed with Pearson’s chi-square test with Yates’ correction when required

Setting

  • Single tertiary pulmonary medicine referral centre, Poland
  • Dates of data collection – not documented

Population

  • Inclusion criteria: Clinical suspicion of acute pulmonary embolism following clinical assessment including history, examination, arterial blood gases, chest x-ray and ECG
  • Exclusion criteria:
    • Time from onset or aggravation of symptoms to study enrolment >14 days
  • 100 patients included
    • 57 male, 43 female
    • Age (mean): 61 years ±15 years
    • 54 patients had known previous cardiorespiratory disease, including 23 patients with diagnosed/suspected COPD, and 17 patients with congestive heart failure
    • 62 patients assessed in the intensive care unit

Tests of Interest

  • Trans-thoracic ECHO
    • 60/60 sign
      • Pulmonary valve acceleration time ≤60ms and tricuspid regurgitation pressure gradient ≤60mmHg
    • McConnell sign
      • Normokinesia +/or hyperkinesia of the apical segment of the RV free wall despite hypokinesia +/or akinesia of the remaining parts of the RV free wall
    • Signs of RV pressure overload, defined as 1 or more of the following signs
      • Right sided cardiac thrombus
      • RV diastolic dimension on parasternal view of >30mm or a ratio of RV to left ventricle of >1
      • Systolic flattening of the interventricular septum
      • Pulmonary valve acceleration time <90ms or tricuspid regurgitation pressure gradient >30mmHg in absence of RV hypertrophy

Gold Standard Investigation

  • APE diagnosed with
    • Spiral CT, n=63 (5mm thick sections, 5mm/s table feed, secondary reconstruction of overlapped images at 3mm intervals)
    • High-probability lung perfusion scan, n=1
    • Pulmonary angiography, n=1
    • Surgery, n=1
    • Autopsy, n=1
  • APE excluded based on
    • Negative CT and negative venous compression ultrasound, n=20
    • Negative lung perfusion scan, n=10
    • Autopsy, n=3
  • Mortality assessed at 1 month

Outcome

  • APE confirmed in 67 patients
    • 60/60 sign
      • Diagnosed 17/67 patients correctly with APE
      • 2 false positives (lung fibrosis n=1, ARDS post bi-lobectomy, n=1)
    • McConnell Sign
      • Diagnosed 13/67 patients correctly with APE
      • No false positives
    • RV pressure overload
      • Diagnosed 54/67 patients correctly with APE
      • 18 false positives

  • In patients without known previous cardiorespiratory diseases, the 60/60 sign and McConnell’s sign were 100% specific for the diagnosis of APE

  • In patients with APE, comparing patients with a +ve 60/60 sign vs. a –ve 60/60 sign, significant difference in:
    • Hypoxaemia: PaO2: 51mmHg vs. 60mmHg, p=0.01
    • Collapsibility of inferior vena cava: 19% vs. 33%, p=0.02
  • ECHO features in patients with vs. without APE
    • RV diameter (mm) measured in parasternal long axis view: 31 vs. 28, p=0.01
    • RV:LV ratio: 0.72 vs. 0.63, p=0.04
    • Septal flattening: 36% vs. 12%, p=0.02
    • Tricuspid regurgitation pressure gradient (mmHg): 41 vs. 28, p=0.01
    • Pulmonary valve acceleration time: 73ms vs. 95ms, p<0.0001
    • Inferior vena cava expiratory diameter: 18mm vs. 16mm, p=0.06
    • IVC collapsibility index: 28% vs. 36%, p=0.22

Authors’ Conclusions

  • The 60/60 sign and McConnell signs are reliable but not sensitive signs of APE

Strengths

  • Consecutive patients
  • Prospective
  • Appropriate gold standard

Weaknesses

  • Population studied from single tertiary pulmonary referral centre with very high prevalence of APE. This limits the external validity
  • Not stated if assessors of test of interest blinded to gold standard investigation
  • No sample size calculation

The Bottom Line

  • In patients seen at a tertiary referral centre with a high pre-test probability of acute pulmonary embolism, the McConnell Sign had a very high positive likelihood ratio. In patients without previous cardiorespiratory disease the 60/60 sign also demonstrated a very high positive likelihood ratio. A negative McConnell or 60/60 sign added little diagnostic information
  • In patients presenting to the ED/ICU with a high probability of acute pulmonary embolism who cannot immediately undergo CT, I will use bedside echo to assess the 60/60 and McConnell’s signs. A positive test result will give me greater confidence for the diagnosis of acute pulmonary embolism, where as a negative result will neither help confirm or repute the diagnosis of acute pulmonary embolism

External Links

Metadata

Summary author: Dave Slessor
Summary date: 10/09/2017
Peer-review editor: Steve Mathieu

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