PB0946 - The wide spectrum of pulmonary thromboembolism on electron microscopy and clinical implications

Monday, June 24, 2024

13:45 – 14:45 ICT

Room: Exhibition Hall

Presenting Author(s)

Arthur M. Freedman, M.D, B.S

Associate Professor, Chief of Interventional Radiology
Medical College of Georgia
Augusta, Georgia, United States

Co-Author(s)

VA

Vishal Arora

Professor
Medical College of Georgia
Augusta, Georgia, United States
BM

Brendan Marshall

Chief of Electron Microscopy, Department of Cell Biology
Medical College of Georgia
Augusta, Georgia, United States
Hw

Hanping wu

Assistant Professor , Interventional Radiology
Medical College of Georgia
Augusta, Georgia, United States
IE

Islam A. Shehata Elhelf, M.D., PhD
mS

musa Sharkawi

Assistant Professor, Structural Cardiology
Medical College of Georgia
Augusta, Georgia, United States
HB

Hal "greg" Bowers

Interventional Radiologist
Medical College of Georgia
Augusta, Georgia, United States
Hg

Harkanwar gill

Assistant Professor , Interventional Radiology
Medical College of Georgia
Augusta, Georgia, United States
jb

jacob beltz

Assistant Professor, Interventional Radiology
Medical College of Georgia
Augusta, Georgia, United States

Background: Current treatments of acute pulmonary embolism (PE) include anticoagulation alone, thrombolytics and catheter embolectomy. Despite these therapies , the incidence of post PE pulmonary hypertension (CTEPH) is between 1.7 and 8% and disability (CTED) ranges from 30-43%. Furthermore, up to 15-20% of patients show lytic resistance.
Pulmonary embolectomy specimens appear grossly heterogenous. Electron microscopy (EM) was selected to further examine the composition of the PE and see if age can be determined
.

Aims: 1. Investigate PE composition with EM
2. Find specific components which explain "lytic resistance."
3. Initiate conversation PE composition and optimization of treatments at the time of diagnosis.
4. Stimulate interest and discussion of the connection between PE composition and long-term CTEPH and CTED among PE survivors

Methods: PE embolectomy specimens from 45 patients treated with embolectomy were sent for EM. The most chronic appearing, (firm, lighter colored) portions of the extracted embolus was submitted for EM. Some older appearing samples were also sent for specific immuno-EM antibody staining for collagen, Von Willibrand's Factor and smooth muscle actin and histones.

Results: Intermediate and chronic stages thrombus formation were found. (Table1) Findings included acute fibrin-platelet mesh platelets, polyhedrocytes, neutrophils, monocytes, macrophages, foam cells, phagocytosis, fibroblasts, smooth muscle cells, collagen type 1, and endothelialization.
80% of samples demonstrated mixed ages of thrombus
23% samples contained collagen (See Table2 )
In many samples thrombus was older than 2 weeks age

Conclusion(s): Pulmonary emboli are heterogenous .
Specific components including collagen implies lytic resistance
Pulmonary emboli are more advanced in age than expected
More study is needed to correlate symptom onset of EM findings
This study suggests anticoagulation and lysis may be is insufficient treatment of older PE.
Explanation why PE never resolve is provided
The incidence of CTEPH and CTED must be considered as related to advanced aged PE and possibly inadequate treatments.