VPB0119 - Evaluation of thrombotic outcomes in patients in a large clinical enterprise following COVID-19 vaccination

Sunday, July 10, 2022

6:30 PM – 7:30 PM

Location: Exhibition

Presentation Format: Virtual

Presenting Author(s)

Brady D. Greene

Medical Student
Cleveland Clinic Foundation
Cleveland, Ohio, United States

Co-Author(s)

WP

William M. Patterson

Medical Student
Cleveland Clinic Lerner College of Medicine of Case Western Reserve University
Cleveland, Ohio, United States
LT

Leben Tefera

Staff Physician
Department of Cardiovascular Medicine, Section of Vascular Medicine, Heart, Vascular & Thoracic Institute, Cleveland Clinic Foundation
Cleveland, Ohio, United States
JB

James Bena

Department of Quantitative Health Sciences, Lerner Research Institute
Cleveland Clinic
Cleveland, Ohio, United States
AM

Alex Milinovich

Director of Research, Data Science Analytics
Quantitative Health Sciences, Cleveland Clinic Foundation
Cleveland, Ohio, United States
NM

Neil B. Mehta

Staff Physician & Associate Dean for Curricular Affairs
Department of Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University
Cleveland, Ohio, United States
MC

Mina K. Chung

Staff Physician
Department of Cardiovascular Medicine, Section of Cardiac Electrophysiology, Heart, Vascular & Thoracic Institute, Cleveland Clinic Foundation
Cleveland, Ohio, United States
SC

Scott J. Cameron

Cardiovascular Medicine Department, Heart, Vascular and Thoracic Institute
Cleveland Clinic
Cleveland, Ohio, United States

Background: With widespread COVID-19 immunization efforts, reports of vaccine-induced thrombocytopenia and thrombosis (VITT) have emerged, particularly in association with adenoviral vector-based vaccines (ChAdOx1 nCoV-19 and Ad26.COV2.S). The incidence of VITT is considered to be extremely low, with the benefits of vaccination strongly outweighing associated risks. Despite the favorable safety profile of COVID-19 vaccines, VITT has garnered the attention of and likely contributes to vaccine hesitancy among a persistently unvaccinated portion of the United States population.

Aims: We sought to characterize thrombotic events following COVID-19 vaccination in a large clinical enterprise where mRNA-based vaccines were mostly administered.

Methods: With institutional approval, medical records of 779,602 patients vaccinated against COVID-19 (2 mRNA-based vaccines: 61.2% BNT162b2, 36% mRNA-1273, and adenovirus-based Ad26.COV2.S, 2.7%) from 12/4/2020-6/6/2021 at Cleveland Clinic Enterprise locations in Ohio and Florida were queried. A baseline complete blood count was available for 223,345 patients, of which 663 (0.3%) demonstrated thrombocytopenia—defined as ≥50% platelet decline 4-28 days post-vaccination—and were subject to chart review. Thrombotic events including deep vein thrombosis, pulmonary embolism, stroke/transient ischemic attack, myocardial infarction, cerebral venous sinus thrombosis, and splanchnic thrombosis were assessed. Thrombotic risk factors including medications, viruses, and malignancy, as well as platelet factor 4 antibody assays were recorded.

Results: Of 76 patients with thrombosis, 63 (82.9%) demonstrated clear etiologies. Thirty (39.5%) had malignancies (24 treated with chemotherapy associated with thrombosis risk). Seven (9.2%) were considered hypercoagulable, six (7.9%) had catheter-related thrombosis, five (6.6%) had recent surgery, five (6.6%) had reduced mobility, five (6.6%) had cardiovascular risk factors, three (3.9%) had diagnosed/suspected immune thrombocytopenia, and two (2.6%) were septic. Of three patients with unprovoked thrombosis, one had findings concerning for VITT (Figure 1).

Conclusion(s): 76/223,345 (0.03%) patients demonstrated thrombosis following COVID-19 vaccination, with one (0.0004%) case concerning for VITT. In a large clinical enterprise, VITT is exquisitely rare.