Pulmonary Embolism: Short of Breathe and Short of Time...

Tom Fuller & Viet Tran

The Case
A 61 yo female is brought in with a 19 hr history of worsening SOB that suddenly become profound thus prompting an ambulance call. Theres no history of chest pain and no past history of cardiac or respiratory disease that you can elucidate through her short gasps.

The Rest of the Case
Otherwise well recently, no sick contacts, no exotic travel history.
Associated symptoms; no chest pain, syncope or palpitations, maybe some left thigh pain but only on prompting
A distant history of what sounds like an unprovoked DVT with unclear follow up but hasn't been on "the rat poison" for years.

Clinical Examination

Looks dreadful! 
​Cyanotic but talking in short phrases
RR 70
Sats 84% RA (89-91% 15L NRBM)
BP 96/48
HR 120
Afebrile

Good AE (when she can)
HSD NM
JVP approx 6cm
Calves SNT without pedal oedema

So Whats Up?
Such sudden drastic deterioration is likely due to a heart (AMI), lung (PXT) or vascular problem (PE, Dissection in coronaries).

And sepsis...sepsis is always on the radar

Investigations

Bedside
ECG - Sinus Tachy, maybe some R heart strain but definitly nothing to catheterise at this stage
VBG - machine broken, being sent to the lab
BSL - 9
Cxr - radiographer on the way

The patients sick and the decision is made for CT to rule out the immediate life threats in the not-so-good looking patient.

CT
So what are we going to order? Non-Con vs CTPA vs Aortagram vs CTCA?  The hooves sound like horses so lets go with the CTPA...

CT Findings
Occlusive thrombus in R main pulmonary artery (shown image 1)
Thrombi in L lobar pulmonary arterial branches
Evidence of R heart strain
Flattening of the interventricular septum
Reflux of contrast into the hepatic arteries and IVC (shown image 2)

PE GRADING
American Heart Association Grading​

MASSIVE
SBP< 90mmHg (15mins or ionotropes) OR
Profound bradycardia with signs of shock OR
Pulselessness (this is bad)

SUBMASSIVE
​SBP>90mmHg with evidence of RV dysfunction (on CTPA, Echo or "Biomarkers")

NON-MASSIVE
Everything else!

So What's Our Patient Have?
SBP > 100mmHg + CTPA shows RV dysfunction + Oh, and the bloods are back...hsTn 119 = SUBMASSIVE

Right, What Do We Do?
Nothing or Anticoagulant or Lyse (systemic or interventional radiology) or Embolectomy or Nothing

---

Some Evidence Around Lysis...

(click on pictures for articles where available)

Fibrinolysis for Patients with Intermediate-Risk Pulmonary Embolism (PEITHO Trial)​
2014
​

• Tenectaplase + heparin vs heparin alone
• Randomised, double-blind, placebo controlled, multicentre
• N=1005 (>18ys, acute onset, submassive PE)
• 1ry outcomet: death or haemodynamic decompensation within 7 days
• Safety outcomes: major bleeding (ICH, other)
• 6 deaths vs 9 (control)
• Less bleeding in <75yo

NNT 33 vs NNH 13.7

Trend toward decreased mortality (non-sig) but increased bleeding (non-sig).

Does not support thrombolysis in submassive PE

Moderate Pulmonary Embolism Treated With Thrombolysis (from the “MOPETT” Trial)
2013

• Prospective, randomised control trial
• N=121

• Moderate PE (based on imaging)
• 1ry outcome: pulmonary HTN on echo 24mo
• ½ dose tPA & anticoagulation vs heparin
• 57% vs 16% (pulm HTN) and no bleeding events
  
• (other studies report pulm HTN post PE in approx 4-5% Px’s and no bleeding)

ARR 41%, NNT 2.4
​
Difficult to interpret study as measured echocardiographic outcomes​

Systematic review and meta-analysis for thrombolysis treatment in patients with acute submassive pulmonary embolism. 
2014

• 7 studies included (inc PEITHO)
• Thrombolysis +/- anticoag vs anticoag
• Mortality from PE 2.7 vs 4.3% (not sig)
• Recurrant PE 2 vs 5% (not sig)
• Major haemorrhage 4.5 vs 3.3% (not sig)
• Minor haemorrhage 41 vs 9% (sig)

---

The Internet...What Does The Internet Have To Say?

• There is a role for thrombolysis in submassive PE.
• The ‘Submassive’ group is too disparate to find an effect based on current definitions.

"Fullers Faith"
Named after the practitioner who provided most of the above information, it is a stream of consciousness that consolidates the evidence and the stuff between the lines

• Some "submassives" are on the way to being massive
• Thrombolysis zeal post N=1 has deflated
• Still a little confused but less than before

All This Talk About Death...What That About?

PESI (Pulmonary Embolism Severity Index) scores 30 day mortality (does not include all the following)

Suggested Interpretation of Score
​
Very Low (≤ 65) or Low Risk (66-85) by the PESI score.

• Patient has an overall low risk of mortality or severe morbidity.
• Consider outpatient management of PE if clinically appropriate and social factors allow for it.

Intermediate (86-105), High Risk (106-125) or Very High Risk (>125) by the PESI.

• Patient has an overall high risk of mortality and severe morbidity.
• Consider higher levels of care (e.g., ICU) for those with higher scores.

​