🫀 Mirza's Cardiology Notes

Amyloidosis

3 min read

  • Related

  • Patients with variant ATTR amyloidosis may experience OH due to autonomic dysfunction

  • Exclude AL amyloidosis with work-up that includes serum FLCs, serum (SIFE), and urine immunofixation

  • Labs may reveal a chronic troponin elevation that remains flat

    • d/t amyloid invasion into the vasculature causing microvascular ischemia

  • Echo:

    • LV wall thickness >1.2 cm (0.6 cm to 1.0 cm is normal) in the absence of hypertension should prompt suspicion for CA. 1
      • LVH is most commonly symmetric, but you may see asymmetric septal hypertrophy, particularly in ATTRwt-CA 1
    • Strain Imaging with “apical sparing,” in which the apical LV segments have normal or near-normal strain compared with the mid and basal segments. 1

Discordance: LVH on Echo and Low-voltage on ECG

If you see LVH on echo but low-voltage on ECG, you should definitely suspect cardiac amyloidosis.

  • ECG may show low-voltage and pseudo-infarct pattern (Q waves in early precordial leads, V1-V2) mimicking prior anteroseptal MI. 1
    • 📝 only about 50% of patients with AL-CA and about 30% of patients with ATTR-CA meet true low-voltage criteria (QRS amplitude <5 mm in limb leads or <10 mm in precordial leads)
    • Wide QRS complexes are more frequent in ATTR-CA and lower limb voltages are more frequent in AL-CA

Pathophysiology

Figure source

Diagnosis

Figure source: 2

Figure source

Concomitant Aortic Stenosis

  • ~15% of TAVR patients have ATTR cardiac amyloid
  • ~15% of ATTR cardiac amyloid patients have moderate to severe AS
  • When both aortic stenosis and ATTR cardiac amyloid occur together, patients will often have low-flow, low-gradient AS because of the stiff heart’s restrictive physiology (→ low stroke volume index)
    • recall, paradoxical low-flow, low-gradient AS occurs with an AVA ≤ 1.0 cm2 with ∆P < 4 m/s and MG < 40 mmHg with preserved ejection fraction (≥ 50%) and SVI < 35 mm/m2

Burnt-out Amyloid

Severe HTN is unlikely to be advanced amyloid

  • If there is enough accumulation of amyloid fibrils, systolic dysfunction can occur → LV unable to adequately perfuse the brain and other organs. These patients may present with bad congestion, but also poor forward flow that is manifested in normal blood pressures despite a history of hypertension and intolerance to neurohomonal blockade, such as BBs, RAASi, etc.
  • From the LVs perspective, you have poor inflow and poor outflow. ∴, ↓ SVR in such patients is not going to translate into improved flow, but rather hypOtension, AKI, and altered mentation.
  • Often very challenging diuresing these patients.

Footnotes

  1. Donnelly JP, Hanna M. Cardiac amyloidosis: An update on diagnosis and treatment. Cleve Clin J Med. 2017 Dec;84(12 Suppl 3):12-26. doi: 10.3949/ccjm.84.s3.02. PMID: 29257735. ↩ ↩2 ↩3 ↩4

  2. Writing Committee; Kittleson MM, Ruberg FL, Ambardekar AV, Brannagan TH, Cheng RK, Clarke JO, Dember LM, Frantz JG, Hershberger RE, Maurer MS, Nativi-Nicolau J, Sanchorawala V, Sheikh FH. 2023 ACC Expert Consensus Decision Pathway on Comprehensive Multidisciplinary Care for the Patient With Cardiac Amyloidosis: A Report of the American College of Cardiology Solution Set Oversight Committee. J Am Coll Cardiol. 2023 Mar 21;81(11):1076-1126. doi: 10.1016/j.jacc.2022.11.022. Epub 2023 Jan 23. Erratum in: J Am Coll Cardiol. 2023 Mar 21;81(11):1135. doi: 10.1016/j.jacc.2023.02.013. PMID: 36697326. ↩

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