thrombolysis in PE

April 13, 2014

An Update on Pulmonary Embolism: NEJM’s PIETHO Study…what’s the verdict? #FOAMed, #FOAMcc

As has been discussed in a previous post (http://wp.me/p1avUV-7T), patients with sub-massive PE (hypoxic, tachycardic, some troponin rise, etc…but no hypotension) remain in a grey zone, which is, to me , a dubious situation at best – their mortality can be up to 15%, morbidity likely more.  Everyone agrees the low-risk patients don’t need thrombolysis, and everyone pretty much agrees that the patient in shock needs it.  There is data out there suggesting that some patients clearly benefit from thrombolysis despite not being in shock, in good part relating to avoiding chronic pulmonary hypertension and its consequences.

The issue for many clinicians is that they have a “stable” patient in front of them, and they are considering giving them a drug that can potentially give them a bleed in the head and leave them dead or crippled. Many shy away from this. Part of this is cultural, because the same docs probably wouldn’t hesitate giving the drug to a lateral or posterior MI, which is not likely to kill you, or even leave you a cardiac cripple (just to be clear, I’m not advocating against thrombolysis in these cases, just trying to find a parallel), but since the AHA guidelines say to do it and everyone else does it, there’s no trepidation. It is the standard of care.  For most of us acute care clinicians who do not do outpatient medicine, if the patient survives and gets discharged home, chalk one up in the win column. But, as has become clear in recent years with the post-critical illness syndromes, morbidity can be just as important as mortality, especially in the younger patients. Kline et al (Chest, 2009) showed how almost 50% of “submassive PE” patients treated with anticoagulation alone had dyspnea or exercise intolerance at 6 months. They only had a 15% improvement in their pulmonary artery pressures (mean 45 mmhg).

What are the real risks? Pooling the data together gives a value around 2% with a spread between 0.8% and 8%, more or less. This represents each patient’s inherent risk of bleeding, as well as some of the inconsistencies with post-thrombolysis anticoagulation (safest to aim for 1.5-2 x PTT baseline in the first 48h).

The MOPETT trial which, as a #FOAMite you have certainly come across, showed that a half-dose of TPA was highly effective, and they felt it might be possible to go lower. The physiological beauty in that is that, unlike other sites we thrombolyse with full dose TPA, the lungs get 100% of the TPA (coronary artery gets maybe 5%, brain gets 15%).  Mind you, of course, the culprit clot/artery obviously doesn’t get 100%, but much, much more (if we figure that you need about 50% vascular area occlusion to cause RV dysfunction) TPA per “clot” than other pathologies. One can argue that anatomically, there is a greater clot burden than coronary or arterial thrombolysis, which may offset this somewhat. However, the date was quite clear in this trial that the therapy was effective, and the bleeding was none.

Ok, so let’s get to the PIETHO. 1000 patients, TPA+heparin vs heparin alone in normotensive but intermediate risk patients. So, first question is how was that risk defined?  Patients needed to have echocardiographic/CT signs of RV dysfunction AND a positive troponin. Interestingly enough, onset of symptoms was up to 15 days before randomization…not exactly early treatment, and unfortunately there is no information about the actual time to thrombolysis or subgrouping.  The results were as one could imagine. The combined endpoint of death or hemodynamic decompensation was 2.6% in the thrombolytic group vs 5.6% in the anticoagulation.  I’m not a fan of combined endpoints. Hemorrhagic stroke was 2.0% vs 0.2%. Their conclusion? Exercise caution. Hmmm…not much of a step forward. Basically tells us what we know. It helps the hemodynamics, but you can bleed. They do re-affirm that bleeding is more likely in the over-75.

 

What do we REALLY need to figure out? 

1. echographic risk stratification – at least into moderate and severe RV dysfunction.

2. longer term outcomes (hopefully PIETHO has a follow-up study in the pipeline, since they had good numbers).

3. a point-of-care study – time is of the essence, and may have an impact on dosage. IMHO thrombolysis should be done within a few hours of presentation at most.

4. further dosage data – 1/2? 1/3? 1/4? small boluses q1h until RV function improves?

I wish I could do it, but community hospitals don’t have the ideal setup, nor do I have a research team that can handle something of this scale. But surely someone can!

 

Bottom line?

It won’t change my practice. I will continue to offer thrombolysis in select cases, especially the younger patients, who obviously have a lower risk of bleeding, and stand to benefit the most, as pulmonary hypertension  can be crippling. I know I’d take the risk of bleeding when I see 50% dyspnea/exercise intolerance two years down the road…

Finally, bedside ultrasound to anyone with dyspnea/hypoxia should be a standard of care for every acute care physician. No ifs, ands or buts, no exception. Waiting for a CT angio or formal (read daytime hours) echocardiogram is, to me, unacceptable. If you, a friend or family member were in that ER bed, would you trust a physical examination and a CXR to rule out the need for an immediate intervention? I wouldn’t, not my own, and not even Dr. Bates’, Dr. DeGowin’s or Dr. Sapira’s, or all three combined.

cheers!

 

 

 

Kline JA, Steuerwald MT, Marchick MR, Hernandez-Nino J, Rose GA. Prospective evaluation of right ventricular function and functional status 6 months after acute submassive pulmonary embolism: frequency of persistent or subsequent elevation in estimated pulmonary artery pressure. Chest 2009;136:1202e1210.

Guy Meyer, M.D., Eric Vicaut, M.D., Thierry Danays, M.D., Giancarlo Agnelli, M.D., Cecilia Becattini, M.D., Jan Beyer-Westendorf, M.D., Erich Bluhmki, M.D., Ph.D., Helene Bouvaist, M.D., Benjamin Brenner, M.D., Francis Couturaud, M.D., Ph.D., Claudia Dellas, M.D., Klaus Empen, M.D., Ana Franca, M.D., Nazzareno Galiè, M.D., Annette Geibel, M.D., Samuel Z. Goldhaber, M.D., David Jimenez, M.D., Ph.D., Matija Kozak, M.D., Christian Kupatt, M.D., Nils Kucher, M.D., Irene M. Lang, M.D., Mareike Lankeit, M.D., Nicolas Meneveau, M.D., Ph.D., Gerard Pacouret, M.D., Massimiliano Palazzini, M.D., Antoniu Petris, M.D., Ph.D., Piotr Pruszczyk, M.D., Matteo Rugolotto, M.D., Aldo Salvi, M.D., Sebastian Schellong, M.D., Mustapha Sebbane, M.D., Bozena Sobkowicz, M.D., Branislav S. Stefanovic, M.D., Ph.D., Holger Thiele, M.D., Adam Torbicki, M.D., Franck Verschuren, M.D., Ph.D., and Stavros V. Konstantinides, M.D., for the PEITHO Investigators*, Fibrinolysis for Patients with Intermediate- Risk Pulmonary Embolism, N Engl J Med 2014;370:1402-11.

Mohsen Sharifi, MDa,b,*, Curt Bay, PhDb, Laura Skrocki, DOa, Farnoosh Rahimi, MDa, and Mahshid Mehdipour, DMDa,b, “MOPETT” Investigators, Moderate Pulmonary Embolism Treated With Thrombolysis (from the “MOPETT” Trial), Am J Cardiol 2012

February 23, 2014

“Doc, I can breathe!” – Thrombolysis in PE…a case discussion. #FOAMed, #FOAMcc

So I was on call last weekend and got a call from one of the internists on the ward about a potential admission who may need dialysis.   She was a woman in her 60’s, diabetic, hypertensive with minimal baseline renal dysfunction, who had been admitted with a hepatic abscess due to biliary obstruction. This had been stented and a pigtail catheter had been inserted to drain the abscess.  However, over the last few days, her creatinine had risen to about 500 and she was becoming oliguric.  Her O2 requirements had also increased and she was now on 15 liters by nasal prongs. This had been ascribed to pleural effusion and possible pneumonia.

When I saw this lady, she was visibly dyspneic at 30 with a heart rate 115-120 and a systolic BP of about 105-110, saturating 90% on 50% face mask.

So on physical examination, she had a soft abdomen (the first thing I feel just before I put probe to skin), her skin was cool, and the CUSE revealed a large (>20mm) IVC with no respiratory variation (despite the effort).  I unfortunately forgot to hit the record clip button…and the parasternal long axis and apical 4 chamber are here:

Lung views showed “A” profiles except for the right base which had a small effusion and some consolidation/atelectasis and some B lines, but not very extensive.

So further assessment revealed she was not a smoker, previously quite active and easily able to go up and down several flights of stairs.  She had noted dyspnea about 3 days ago, without chest pain. There were no leg symptoms, and she had been on LMWH for dot prophylaxis.  The CXR was not very impressive – in a sense that there was not enough parenchymal disease to explain pulmonary hypertension.

This is PE until proven otherwise, and I would have been comfortable without further confirmation, but with the presence of some lung disease and an intrahepatic catheter, I preferred to have 100% confirmation before initiating thrombolysis.

After CT angiogram confirming bilateral and extensive embolism, I had a thorough discussion with her and her family and they all agreed to go ahead with TPA.  She was quite concerned with cardiorespiratory limitation, given that she was quite active. She was comfortable with a quoted risk of intracerebral bleeding below 2%. I used the MOPETT half-dose of 50mg.

Overnight, her HR slowed to about 100, and sats increased to 93-94%.

When I rounded on her in the morning, she said “Doc, I can breathe!” with a big grin. Her HR was 95-100, she was not on 3 litters by NPs, BP 115-120 systolic, and CUSE showed:

So we can see that even though the RV is still quite impaired, it has decreased in size and the LV is now filling better. This was about 12-13h post thrombolysis. She was able to sit up without dyspnea and mobilize to the chair. Her IVC, although it remained around 18-19 mm, had clear respiratory variation.

So…success? Who really knows. It is concievable that, with heparin alone, she might have improved similarly. It is possible. I’m not putting this up to formally support the concept of thrombolysis in “submassive” PE but more to contribute to the #FOAMed discussion regarding the “grey zone” of thrombolysis, since she was technically not in shock (eg SBP>90, lactate normal), but the degree of impairment of the RV to me and the clinical picture, 3 days post, was concerning enough to warrant thrombolysis, but importantly to stress the following:

Point 1: the importance of bedside ultrasound, especially in acute cases.  Without it, over a weekend, and with a patient in renal failure, how quickly would I have ordered a CT angio?  Not without some hesitation…

I won’t review the MOPETT trial, these guys did a much better job than I could hope to, so definitely listen to this if this topic is of any interest to you (and it should!!!):

http://emcrit.org/wee/mopett-trial/

http://ragepodcast.com/rage-session-two/

Great case debates in the RAGE podcast.

Keep in mind that morbidity, not mortality, is the main thing to focus on in sub-massive embolism and the MOPETT – even though I don’t really like the term, its quite vague – benefit in embolism with shock is quite clear.

Point 2: Equally interesting to me was the fact that the renal failure improved. In fact, overnight following thrombolysis, she had a urine output (without diuretic) over a litre, and over the next few days her creatinine normalized and renal replacement therapy was not needed.  Interesting, since she even got a good blast of toxic dye with the CT.  Some will feel that it is the improvement in CO that improved renal function, and this may be partly true, but in view of the lack of “systemic shock,” I think that venous decompression resolved the congestive renal failure, which I think was the main cause of her ARF. I posted about this topic a few months ago, so for more on this see:

https://thinkingcriticalcare.com/2013/09/25/chf-associated-renal-failure-low-flow-or-not/

so thanks for reading and love to hear anyone’s opinion!

PR

COMMENTS:

QUESTION. IF SOMEONE DOES NOT HAVE A PALPABLE PULSE BUT HAS CARDIAC ACTIVITY ON THE ECHO AND RATE IS 90 AND BP IS 50.  DO YOU CONSIDER THIS PEA AND INITIATE CPR?

SEAN

Great question!  There is a whole grey area in “PEA” and management is unclear. I don’t think there is a single answer to that, but physiologically and without further information about RV/LV, I would say your patient needs vasopressor/inotrope support, so I would probably give a small bolus of epi (maybe 100ug) and start an infusion. If I see little reaction (eg HR/BP doesn’t pick up in 30 seconds, I would probably give a short cycle of CPR to get the epi back to the heart.   Of course, hopefully there is a reversible cause (MI/PE), that can be addressed.

Thanks!

 

Philippe