ZSFG AM Report 7/13 pearls: STE, PAILS, life of coronary artery graft

Thanks to Alayn for presenting the case of 65W h/o CAD s/p CABG who was activated as a STEMI based on a concerning EKG, had a clean cath, and ultimately presentation was most consistent with HTN emergency.

5(+1) life-threatening causes of chest pain to always consider when evaluation pt w/ CP:

  • Aortic dissection
  • ACS
  • PTX
  • Tamponade
  • Esophageal rupture
  • (PE)

 

Causes of ST elevation to keep in mind…not all STE is a STEMI:

  • ACS
  • LVH
  • Early Repol
  • LBBB
  • Brugada syndrome
  • Pericarditis
  • Left Ventricular aneurysm
  • Paced rhythms
  • Hyperkalemia

 

tombstone.png

Remind ourselves of the ECG diagnostic criteria for STEMI…also found in Agile MD:

  • ST elevations in ≥2 contiguous leads: ≥2 mm for men or ≥1.5 mm for women in V2-V3, and/or ≥1 mm (both genders) in other contiguous leads
  • In isolation (without clinical correlate), new LBBB is not diagnostic of MI (see Sgarbossa Criteria below)
  • If there are ST changes in the inferior distribution (II, III, aVF), rule out right ventricular STEMI. Obtain right-sided leads and look for ST elevation in V4R.
  • If there is ST depression in anterior leads (V1-V3) or R>S in V1, get posterior leads to rule out posterior STEMI
  • In Left Bundle Branch Blocks…..
    • Sgarbossa Criteria score of at least 3 has a sensitivity of 36% and specificity of 90% for acute MI
    • Given poor sensitivity of these criteria, consider emergent cath regardless of morphology of LBBB if story is good for ACS
    • Criteria
      • STE of 1mm or more in the same direction of the QRS in any lead (concordance) is 5 points
      • ST depression of 1mm in any of V1-V3 is 3 points
      • STE of 5mm or more in the opposite direction as the QRS in any lead (discordance) is 3 points

PAILS mnemonic (courtesy of Braden, Nalini, and cards fellows everywhere) for anatomical location of reciprocal changes in relation to ST elevations:

  • Posterior, Anterior, Inferior, Lateral, Septal
  • If elevations in one letter, following letter will have the reciprocal changes or depressions
  • For example: ST elevation in anterior leads should produce depression in inferior leads, and elevation in lateral leads should produce depression in septal leads

The life of a coronary artery graft:grafts

  • If you’re a SAPHENOUS VEIN GRAFT
    • About 10% of SVGs are occluded early postoperatively (<6 months), 20% at 1 year and 50% at 10 years of follow-up. Moreover 70% of SVGs are diffusely diseased at 10 years, some totally obstructed or showing angiographic evidence of pathologic changes
  • If you’re an INTERNAL THORACIC ARTERY AKA Mammary Artery GRAFT
    • LITA/LIMA to LAD graft have a more than 90% chance of functioning well early after operation, but that these grafts continued to function well for many years and that even 20 years after operation the development of obstructions in these grafts is extremely uncommon
  • See Table below on patency of grafts from Cardiovascular Revascularization Medicine (yup, that’s a journal)
Graft Patency at 1 year Patency at 4–5 years Patency at 10–15 years
SVG > 90% 65–80% 25–50%
RA* 86–96% 89% not reported
Left IMA > 91% 88% 88%
Right IMA Not reported 96% 65%

IMA internal mammary artery; *RA radial artery; SVG saphenous vein graft
Consider the following for causes of ACS in patients who are s/p CABG:

  • Native vessel occlusion
  • Graft occlusion (early vs late graft failure)
  • Dissection

 

References:
-Cleveland Clinic, Agile MD, UpToDate, google images.
-Lytle BW et al. Long-term (5 to 12 years) serial studies of internal mammary artery and saphenous vein coronary bypass grafts. J Thorac Cardiovasc Surg. 1985 Feb;89(2):248-58. -Scarsini R et al. Repeat revascularization: Percutaneous coronary intervention after coronary artery bypass graft surgery. Cardiovascular Revascularization Medicine. Volume 17, Issue 4, June 2016, Pages 272–278. doi:10.1016/j.carrev.2016.04.007

 

Evernote link:
https://www.evernote.com/shard/s354/sh/fd296b44-a3c6-473c-9282-ba9506044d7f/3c09a5001aa25f11f0e97d20110970aa

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