Acute pulmonary embolism

High-risk pulmonary embolism (One of the following)

Cardiac arrest

Obstructive shock

90

Systolic BP < 90 mmHg

OR

Vasopressor required

to achieve a BP >_90 mmHg despite adequate filling status

And

End organ hypoperfusion

(oliguria, alter mental status or increase serum lactate)

Persistent hypotension

90

40

mmHg

Systolic BP < 90 mmHg

OR

systolic BP drop >_40 mmHg,

lasting longer than 15 min and not caused by new-onset arrhythmia, hypovolaemia, or sepsis

None of above ?: See Not high risk.

Suspected PE with hemodynamic instability

Probability for PE

The D-dimer test cut-off value is 0.5 ng/mL or 500 mg/L (some hospitals use mg/L as the unit).

Age-adjusted cut-off value

calculated by adding 10 times the age over 50 to the standard cut-off value. For example, if the patient is 55 years old, the cut-off value would be 550 ng/mL.

Age (year)

Cut-off: 500 ng/ml (0.5 mg/L)

A reliable method for diagnosis is to use the ELISA technique for D-dimer to achieve high sensitivity, which can exclude acute pulmonary embolism in low-probability patients.

Method	Time	Sensitivity (%)	Specificity (%)
Enzyme Linked Immunosorbent Assay (ELISA)	> 8 hours	95	46 - 68%
Quantitative Rapid ELISA	30 min
Semi quantitative rapid ELISA	10 min
Qualitative rapid ELISA	10 min	90
Quantitative latex agglutination assay	10 - 15 min
Semi quantitative latex	5 min	86
Erythrocyte agglutination assay	2 min	82

Echocardiography

Parasternal long axis (PLAX)

In the parasternal long axis view, there is an enlargement of the right ventricle (the structure of the right chamber of the heart located at the front adjacent to the sternum).

Parasternal short axis (PSAX)

The right ventricle appears enlarged in the parasternal short axis view. During acute right ventricular pressure load, the high pressure in the rightricle compresses the interventricular septum, causing a characteristic LV-D shape where both the left and right ventricles share the septum.

Apical four chamber (A4C)

The Apical four-chamber view image shows that the right ventricle is larger than the left ventricle in comparison.

CW

TR pressure gradient ≤ 60 mmHg

PW

PA acceleration time ≤ 60 msec

The 60/60 Sign consists of TR pressure gradient ≤ 60 mmHg and PA acceleration time ≤ 60 msec. According to the 2019 ESC guideline on acute PE, the TR pressure gradient is used for the 60/60 sign, not RVSP.

To measure TR pressure gradient, use the parasternal short axis at the level of the aortic valve and CW to measure TR Vmax. Then, calculate with the formula TRPG = 4 V².

Pulmonary artery acceleration time can be measured by opening the pulmonary artery view, placing the sample volume at the pulmonic valve position, adjusting the Sweep speed, and measuring from onset to peak flow velocity.

Typically, the pulmonary artery waveform has a rounded contour. Still, if pulmonary resistance increases, it will have a shaped point max peak, an asymmetrical 'W,' with a Doppler notch.

Tricuspid Annular Plane Systolic Excursion (TAPSE)

DOI: https://doi.org/10.21980/J8M052

TAPSE is a measurement of the longitudinal function of the right ventricle, which can be obtained through echocardiography in the Modified Apical four-chamber view using M-mode to measure the distance of motion of the lateral tricuspid annulus. If TAPSE is ≤ 16 mm, it indicates right ventricular longitudinal dysfunction.

Modified four-chamber view

Mechanism:

During an acute pulmonary embolism, there is a sudden increase in the right ventricular pressure load, which can lead to right ventricle hypoperfusion and ischemia.

The right coronary artery supplies the lateral right ventricle, and the left anterior descending artery supplies the apical right ventricle.

Therefore, this results in akinesia of the mid-right ventricle free wall (green arrows) while hyperkinesia of the right ventricular apical wall (purple arrows). the sensitivity of McConnell's sign to be only 22%

Although McConnell's sign has high specificity, it may need to be differentiated from other conditions, such as acute right ventricular infarction and chronic pulmonary hypertension.

Ramos H R, Ceballos M, Alvarenga H, et al. (September 26, 2019) Catheter-based Therapy for Massive Pulmonary Embolism in an Elderly Woman with Chest Pain and Dyspnea: Case Report. Cureus 11(9): e5771. doi:10.7759/cureus.5771

CTPA

DOI: https://doi.org/10.21980/J8N63P

A thrombus in the shape of a saddle is lodged at the bifurcation of the pulmonary artery, as seen in the CTPA.

DOI:10.7759/cureus.7771

In the CTPA, the right ventricle enlarged in comparison to the left ventricle.

Management of RV failure in acute high risk acute pulmonary embolism

Norepinephrine (0.2-1 ug/kg/min)

The left ventricle is perfused mainly during diastole. Because the LV produces a higher internal pressure during systole, systolic coronary resistance increases, and systolic coronary blood flow is lower.

The right ventricle receives equal perfusion during systole and diastole. However, in cases of acute PE, there is an acute increase in right ventricular systolic pressure (RVSP), which leads to right ventricular ischemia. Administering vasopressors can help increase blood pressure, restore coronary perfusion pressure gradient, and improve right ventricle inotropy.

Int J Cardiol. 2018 Dec 1;272S:46-52.

Norepinephrine is commonly used to treat persistent hypotension by constricting blood vessels through α1—and β1 —adrenoceptors. However, it may increase pulmonary vascular resistance (PVR).

Vasopressin, on the other hand, acts as a systemic vasoconstrictor and pulmonary vasodilator, making it a potential alternative to norepinephrine. Nonetheless, there is limited data on using Vasopressin in patients with RHF.

Risk stratification

PESI score (Pulmonary Embolism Severity Index)

PESI score

Class I: ≤65 points, very low 30-day mortality risk (01.6%)

Class II: 66 - 85 points, low mortality risk (1.73.5%)

Class III: 86 - 105 points, moderate mortality risk (3.2-7.1%) Class IV: 106 - 125 points, high mortality risk (4.0 - 11.4%) Class V: >125 points, very high mortality risk (10.0 - 24.5%)

Simplified PESI

0 points: 30-day mortality risk 1.0% (95% CI 0.0 - 2.1%)

1 ≥ point(s): 30-day mortality risk 10.9% (95% CI 8.5 - 13.2%)

For patients with PESI class III-IV or sPESI ≥ 1, the mortality risk is intermediate.

If both RV dysfunction on TTE or CTPA AND elevated troponin levels are present, the risk is intermediate-high.

If one of the above or none, the risk is intermediate-low.

Patients who have acute PE and are hemodynamically unstable are at a high risk.

For PESI class I-II and sPESI = 0

The mortality risk is low if there is no RV dysfunction on TTE or CTPA.

However, if there is RV dysfunction, a troponin test should be performed.

If the troponin test is positive, the risk is intermediate-high,

if the troponin test is negative, the risk is intermediate-low.

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References

1) Konstantinides SV, Meyer G, Becattini C, Bueno H, Geersing GJ, Harjola VP, et al. 2019 ESC Guidelines for the diagnosis and management of acute pulmonary embolism developed in collaboration with the European Respiratory Society (ERS): The Task Force for the diagnosis and management of acute pulmonary embolism of the European Society of Cardiology (ESC). European Heart Journal. 2020 Jan 21;41(4):543–603.

2) Ramos H R, Ceballos M, Alvarenga H, et al. (September 26, 2019) Catheter-based Therapy for Massive Pulmonary Embolism in an Elderly Woman with Chest Pain and Dyspnea: Case Report. Cureus 11(9): e5771. doi:10.7759/cureus.5771

3) Sathe P, Patwa U. D Dimer in acute care. International journal of critical illness and injury science. 2014 Jul 1;4:229–32.

4) Olsson KM, Halank M, Egenlauf B, Fistera D, Gall H, Kaehler C, Kortmann K, Kramm T, Lichtblau M, Marra AM, Nagel C, Sablotzki A, Seyfarth HJ, Schranz D, Ulrich S, Hoeper MM, Lange TJ. Decompensated right heart failure, intensive care and perioperative management in patients with pulmonary hypertension: Updated recommendations from the Cologne Consensus Conference 2018. Int J Cardiol. 2018 Dec 1;272S:46-52. doi: 10.1016/j.ijcard.2018.08.081. Epub 2018 Aug 26. PMID: 30190155.