Long Covid19NCT05635552
All Eyes on PCS - Analysis of the Retinal Microvasculature in Patients With Post-COVID-19 Syndrome
An observational study of Long Covid19 and Post COVID-19 Condition, run by Technical University of Munich at 1 site in Germany.
Trial summary
The goal of this observational, prospective study is to in depth analyze the retinal microvasculature in patients with Post-COVID-19 Syndrome (PCS). The main questions it aims to answer is: Do patients with PCS show a prolonged endothelial dysfunction when compared with fully COVID-19 recovered participants? Does… Read more about this study
- Who is it for?
- Ages 18 years and olderHealthy volunteers can take part
- Conditions the study is for
- Long Covid19, Post COVID-19 Condition, Endothelial Dysfunction
- What is being tested?
- Dynamic retinal vessel analysis (DVA), Optical coherence tomography (OCT) and Biochemistry and immune phenotyping
- How many people
- 300 participants
- Where
- 1 siteGermany
- Study dates
- 17 Oct 2022to 21 Jul 2023
- Phase
- Observational
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Study population: Community sample, Post-Covid ambulance, general practitioner
Who may be able to join
- Patients with Post-COVID syndrome (positive PCR or positive rapid antibody test ≥3 months) with a currently existing, PCS-typical complaint complex, ongoing for at least 2 months and cannot be explained by an alternative diagnosis.
- Control group: recovered from COVID-19 infection (positive PCR or positive rapid antibody test ≥ 3 months) without residual symptoms.
- Healthy cohort: no history of COVID-19 infection
Who cannot join
- Missing or incomplete consent form
- Age < 18 years
- Pregnancy
- Malignancy
- Diseases associated with a significant change in life expectancy
- Autoimmune diseases of the rheumatological type
Show all 9Show fewer
- Cataract
- Epilepsy
- Glaucoma
Trial locations and contacts
1 site in 1 country.
Germany1 site, 1 recruiting
- Recruiting
Klinikum rechts der Isar
München, Bavaria, 81675
Christoph Schmaderer, Prof. Dr, 089 4140 5053, christoph.schmaderer@mri.tum.de
Timon Kuchler, 089 4140 8189, timon.kuchler@mri.tum.de
About this study
The goal of this observational, prospective study is to in depth analyze the retinal microvasculature in patients with Post-COVID-19 Syndrome (PCS). The main questions it aims to answer is:
Do patients with PCS show a prolonged endothelial dysfunction when compared with fully COVID-19 recovered participants? Does symptom severity in PCS patients correlate with the extend of endothelial dysfunction? Do these changes correlate with improvement in symptoms in the prospective observation?
Read the detailed description
The investigators will recruit patients with PCS, fully COVID-19 recovered participants and COVID-19 infection naïve participants. After comprehensive clarification and given written informed consent, measurements will take place in the Klinikum rechts der Isar. To evaluate the retinal microvasculature dynamic retinal vessel analysis (DVA) and optical coherence tomography (OCT) are used. Patient reported outcomes (PROM) of PCS typical symptoms will be collected using standardized questionnaires. To ensure data quality the investigators will use standard operating procedures (SOP) for both technical measurements and data collection. For DVA measurements all examiners will be trained by a single experienced supervisor and must reach high image accuracy and quality in at least 10 volunteers. Examiners are only involved in data acquisition.
- Being tested
- Dynamic retinal vessel analysis (DVA), Optical coherence tomography (OCT), Biochemistry and immune phenotyping, Handgrip strength test, Questionnaires (Patient reported outcomes)
- Keywords
- Retinal Vessel Analysis, Retinal microvasculature, Autoimmunity, Inflammation, Vasculopathy
- Medical subject headings
- Post-Acute COVID-19 Syndrome, Autoimmune Diseases, Inflammation, Vascular Diseases
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Dynamic retinal vessel analysis (DVA)Diagnostic test
DVA is an established, non-invasive tool to measure the responsiveness of retinal vessels to flickering light. In addition static retinal vessel parameters are recorded.
Optical coherence tomography (OCT)Diagnostic test
OCT is an imaging technique which applies low-coherence light to capture high resolution images from the ocular fundus.
Biochemistry and immune phenotypingDiagnostic test
Blood sample collection for clinical chemistry and isolation of PBMCs for FACS analysis.
Handgrip strength testDiagnostic test
Measure the maximum isometric strength of the hand and forearm muscles and their fatiguability.
Questionnaires (Patient reported outcomes)Diagnostic test
The questionnaires evaluate anxiety, depression, chronic fatigue, quality of life, and post-covid typical symptoms
| Study group | Role | What they receive |
|---|---|---|
| PCS patients | Patients with a COVID-19 infection at least 3 months ago (positive PCR or rapid antibody test) and PCS typical symptoms (e.g. fatigue, breast pain, heart palpitations, cognitive impairment) ongoing for at least 2 months and which cannot be explained by an alternative diagnosis. Receives: Diagnostic Test: Dynamic retinal vessel analysis (DVA); Diagnostic Test: Optical coherence tomography (OCT); Diagnostic Test: Biochemistry and immune phenotyping; Diagnostic Test: Handgrip strength test; Diagnostic Test: Questionnaires (Patient reported outcomes) | |
| COVID-19 recovered participants | Participants with Sars-CoV-2 infection at least 3 months ago (positive PCR or positive rapid antibody test) which are fully recovered. Receives: Diagnostic Test: Dynamic retinal vessel analysis (DVA); Diagnostic Test: Optical coherence tomography (OCT); Diagnostic Test: Biochemistry and immune phenotyping; Diagnostic Test: Handgrip strength test; Diagnostic Test: Questionnaires (Patient reported outcomes) | |
| COVID-19 infection naïve | No history of COVID-19 infection (exclusion via measurement of specific antibodies).
Consists of an already established, pre-pandemic healthy cohort and a cohort recruited during the pandemic. Receives: Diagnostic Test: Dynamic retinal vessel analysis (DVA); Diagnostic Test: Optical coherence tomography (OCT); Diagnostic Test: Biochemistry and immune phenotyping |
What is being measured
The primary outcome is the main question the study is designed to answer.
PCS patients show an impaired retinal vessel responsiveness when compared with fully recovered COVID-19 participants.
Static and dynamic parameters of the retinal vessel analysis.
Measured: Baseline
Secondary outcomes (7)
PCS patients show an impaired retinal vessel responsiveness at baseline when compared with infection naïve participants.
Static and dynamic parameters of the retinal vessel analysis.
Measured: Baseline
PCS patients with improved symptoms show a change in retinal vessel responsiveness after 6 months when compared with baseline parameters.
Static and dynamic parameters of the retinal vessel analysis. Test items of the The COVID-19 Yorkshire Rehabilitation Scale (C19-YRS) and PCS questionnaire. Calculation of PCS severity scores (Bahmer, 2022) in each patient with a range of score values from zero (better outcome) to 59 (worse outcome). Comparison of retinal vessel parameters and PCS scores between Baseline and month 6.
Measured: Baseline to month 6
Symptom severity of PCS in patients correlates with impaired retinal vessel responsiveness.
Correlation between PCS severity scores with static and dynamic parameters of the retinal vessel analysis.
Measured: Baseline
PCS patients with impaired RVA analysis show elevated levels of markers of endothelial dysfunction and of chronic inflammation when compared with COVID-19 recovered cohort.
Measurement of markers of endothelial dysfunction:
Concentration of: sICAM, sVCAM, Thrombomodulin, P-Selectin,E-Selectin, ADMA, SADMA, Endothelin-1, ACE-1, ACE-2, ANG-2, GDF-15.
Measurement of markers of chronic inflammation Concentration of IFN-β, IFN-λ1,TNFa. Comparison of marker levels to the COVID-19 recovered cohort.
Measured: Baseline
PCS patients with impaired RVA show a reactivation of EBV.
Using PCR to measure EBV reactivation in patients plasma .
Measured: Baseline
Characterization of immune cell composition in PCS patients and comparison with COVID-19 recovered and COVID-19 infection naïve participants.
Using flow cytometry to detect different T-cell and monocyte subpopulations.
Measured: Baseline
PCS patients show a decrease in vessel density in OCT-A when compared with COVID-19 recovered participants.
Parameters of OCT-A.
Measured: Baseline
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted2 Dec 2022
- Study start17 Oct 2022
- Primary completion21 Feb 2023 (estimated)
- Study completion21 Jul 2023 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (5)Papers the sponsor has linked to this study.
- Other trials for Long Covid19Studies of the same condition, open and under way.
- More trials run by Technical University of MunichThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Case-control
- Time perspective
- Prospective
- Enrolment
- 300 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Technical University of Munich
- Sponsor type
- University, hospital or other
- Collaborators
- Ludwig-Maximilians - University of Munich
- Responsible party
- Principal investigator, PD Dr. Christoph Schmaderer, Technical University of Munich
- Investigators
- Christoph Schmaderer, Prof. Dr., Principal investigator, Technical University Munich
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05635552
- Sponsor's protocol ID
- 2022317PCS
- Status last verified
- Nov 2022
- First submitted
- 18 Nov 2022
- Last updated
- 2 Dec 2022
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Bahmer T, Borzikowsky C, Lieb W, Horn A, Krist L, Fricke J, Scheibenbogen C, Rabe KF, Maetzler W, Maetzler C, Laudien M, Frank D, Ballhausen S, Hermes A, Miljukov O, Haeusler KG, Mokhtari NEE, Witzenrath M, Vehreschild JJ, Krefting D, Pape D, Montellano FA, Kohls M, Morbach C, Stork S, Reese JP, Keil T, Heuschmann P, Krawczak M, Schreiber S; NAPKON study group. Severity, predictors and clinical correlates of Post-COVID syndrome (PCS) in Germany: A prospective, multi-centre, population-based cohort study. EClinicalMedicine. 2022 Jul 18;51:101549. doi: 10.1016/j.eclinm.2022.101549. eCollection 2022 Sep.
PubMed 35875815Wallraven T, Gunthner R, Lethen I, Ribeiro A, Lech M, Oertel FC, Reess LG, Haller B, Streese L, Hanssen H, Basta-Wunderle M, Schmaderer C. Microvascular remodeling and endothelial dysfunction across the post-COVID-19 spectrum: a prospective observational case-control study. BMC Med. 2026 Aug 19;24(1):456. doi: 10.1186/s12916-026-05144-9.
PubMed 42625188Wunderle M, Ribeiro A, Lethen I, Schmaderer C, Wallraven T. Persistent impairments in muscle function and symptom burden in post-COVID syndrome: a prospective longitudinal study. J Transl Med. 2026 Jul 7;24(1):871. doi: 10.1186/s12967-026-08579-z.
PubMed 42415070Kuchler T, Hausinger R, Braunisch MC, Gunthner R, Wicklein R, Knier B, Bleidissel N, Maier M, Ribero A, Lech M, Adorjan K, Stubbe H, Kotliar K, Heemann U, Schmaderer C. All eyes on PCS: analysis of the retinal microvasculature in patients with post-COVID syndrome-study protocol of a 1 year prospective case-control study. Eur Arch Psychiatry Clin Neurosci. 2024 Dec;274(8):1847-1856. doi: 10.1007/s00406-023-01724-5. Epub 2023 Dec 2.
PubMed 38041762Kuchler T, Gunthner R, Ribeiro A, Hausinger R, Streese L, Wohnl A, Kesseler V, Negele J, Assali T, Carbajo-Lozoya J, Lech M, Schneider H, Adorjan K, Stubbe HC, Hanssen H, Kotliar K, Haller B, Heemann U, Schmaderer C. Persistent endothelial dysfunction in post-COVID-19 syndrome and its associations with symptom severity and chronic inflammation. Angiogenesis. 2023 Nov;26(4):547-563. doi: 10.1007/s10456-023-09885-6. Epub 2023 Jul 28.
PubMed 37507580
Study at a glance
From the registry record, last updated by the sponsor on 2 Dec 2022. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- All Eyes on PCS - Analysis of the Retinal Microvasculature in Patients With Post-COVID-19 Syndrome
- ClinicalTrials.gov ID
- NCT05635552
- Acronym / sponsor ID
- 2022317PCS
- Keywords
- Retinal Vessel Analysis, Retinal microvasculature, Autoimmunity, Inflammation, Vasculopathy
- Study type
- Observational
- Recruitment status
- Unknown status
- Enrolment
- 300 participants (estimated)
- Lead sponsor
- Technical University of MunichUniversity, hospital or other
- Collaborators
- Ludwig-Maximilians - University of Munich
- Study start
- 17 Oct 2022 (actual)
- Primary completion
- 21 Feb 2023 (estimated)
- Study completion
- 21 Jul 2023 (estimated)
- First posted
- 2 Dec 2022 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The goal of this observational, prospective study is to in depth analyze the retinal microvasculature in patients with Post-COVID-19 Syndrome (PCS). The main questions it aims to answer is:
Do patients with PCS show a prolonged endothelial dysfunction when compared with fully COVID-19 recovered participants? Does symptom severity in PCS patients correlate with the extend of endothelial dysfunction? Do these changes correlate with improvement in symptoms in the prospective observation?
Detailed description
The investigators will recruit patients with PCS, fully COVID-19 recovered participants and COVID-19 infection naïve participants. After comprehensive clarification and given written informed consent, measurements will take place in the Klinikum rechts der Isar. To evaluate the retinal microvasculature dynamic retinal vessel analysis (DVA) and optical coherence tomography (OCT) are used. Patient reported outcomes (PROM) of PCS typical symptoms will be collected using standardized questionnaires. To ensure data quality the investigators will use standard operating procedures (SOP) for both technical measurements and data collection. For DVA measurements all examiners will be trained by a single experienced supervisor and must reach high image accuracy and quality in at least 10 volunteers. Examiners are only involved in data acquisition.
Study design
- Observational model
- Case-control
- Time perspective
- Prospective
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| PCS patients | – | Diagnostic Test: Dynamic retinal vessel analysis (DVA), Diagnostic Test: Optical coherence tomography (OCT), Diagnostic Test: Biochemistry and immune phenotyping, Diagnostic Test: Handgrip strength test, Diagnostic Test: Questionnaires (Patient reported outcomes)Patients with a COVID-19 infection at least 3 months ago (positive PCR or rapid antibody test) and PCS typical symptoms (e.g. fatigue, breast pain, heart palpitations, cognitive impairment) ongoing for at least 2 months and which cannot be explained by an alternative diagnosis. |
| COVID-19 recovered participants | – | Diagnostic Test: Dynamic retinal vessel analysis (DVA), Diagnostic Test: Optical coherence tomography (OCT), Diagnostic Test: Biochemistry and immune phenotyping, Diagnostic Test: Handgrip strength test, Diagnostic Test: Questionnaires (Patient reported outcomes)Participants with Sars-CoV-2 infection at least 3 months ago (positive PCR or positive rapid antibody test) which are fully recovered. |
| COVID-19 infection naïve | – | Diagnostic Test: Dynamic retinal vessel analysis (DVA), Diagnostic Test: Optical coherence tomography (OCT), Diagnostic Test: Biochemistry and immune phenotypingNo history of COVID-19 infection (exclusion via measurement of specific antibodies). Consists of an already established, pre-pandemic healthy cohort and a cohort recruited during the pandemic. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
- Study population
- Community sample, Post-Covid ambulance, general practitioner
Key inclusion criteria (3 listed)
- Patients with Post-COVID syndrome (positive PCR or positive rapid antibody test ≥3 months) with a currently existing, PCS-typical complaint complex, ongoing for at least 2 months and cannot be explained by an alternative diagnosis.
- Control group: recovered from COVID-19 infection (positive PCR or positive rapid antibody test ≥ 3 months) without residual symptoms.
- Healthy cohort: no history of COVID-19 infection
Key exclusion criteria (9 listed)
- Missing or incomplete consent form
- Age < 18 years
- Pregnancy
- Malignancy
- Diseases associated with a significant change in life expectancy
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Dynamic retinal vessel analysis (DVA)DVA is an established, non-invasive tool to measure the responsiveness of retinal vessels to flickering light. In addition static retinal vessel parameters are recorded. | Diagnostic test | COVID-19 infection naïve, COVID-19 recovered participants, PCS patients |
| Optical coherence tomography (OCT)OCT is an imaging technique which applies low-coherence light to capture high resolution images from the ocular fundus. | Diagnostic test | COVID-19 infection naïve, COVID-19 recovered participants, PCS patients |
| Biochemistry and immune phenotypingBlood sample collection for clinical chemistry and isolation of PBMCs for FACS analysis. | Diagnostic test | COVID-19 infection naïve, COVID-19 recovered participants, PCS patients |
| Handgrip strength testMeasure the maximum isometric strength of the hand and forearm muscles and their fatiguability. | Diagnostic test | COVID-19 recovered participants, PCS patients |
| Questionnaires (Patient reported outcomes)The questionnaires evaluate anxiety, depression, chronic fatigue, quality of life, and post-covid typical symptoms | Diagnostic test | COVID-19 recovered participants, PCS patients |
Primary outcome
PCS patients show an impaired retinal vessel responsiveness when compared with fully recovered COVID-19 participants.
Time frame: Baseline
Static and dynamic parameters of the retinal vessel analysis.
7 secondary outcomes
PCS patients show an impaired retinal vessel responsiveness at baseline when compared with infection naïve participants.
Time frame: Baseline
PCS patients with improved symptoms show a change in retinal vessel responsiveness after 6 months when compared with baseline parameters.
Time frame: Baseline to month 6
Symptom severity of PCS in patients correlates with impaired retinal vessel responsiveness.
Time frame: Baseline
PCS patients with impaired RVA analysis show elevated levels of markers of endothelial dysfunction and of chronic inflammation when compared with COVID-19 recovered cohort.
Time frame: Baseline
PCS patients with impaired RVA show a reactivation of EBV.
Time frame: Baseline
Characterization of immune cell composition in PCS patients and comparison with COVID-19 recovered and COVID-19 infection naïve participants.
Time frame: Baseline
PCS patients show a decrease in vessel density in OCT-A when compared with COVID-19 recovered participants.
Time frame: Baseline
Results and safety
Results are not available in the source record.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 2 Dec 2022.
- Background: PubMed 35875815Bahmer T, Borzikowsky C, Lieb W, Horn A, Krist L, Fricke J, Scheibenbogen C, Rabe KF, Maetzler W, Maetzler C, Laudien M, Frank D, Ballhausen S, Hermes A, Miljukov O, Haeusler KG, Mokhtari NEE, Witzenrath M, Vehreschild JJ, Krefting D, Pape D, Montellano FA, Kohls M, Morbach C, Stork S, Reese JP, Keil T, Heuschmann P, Krawczak M, Schreiber S; NAPKON study group. Severity, predictors and clinical correlates of Post-COVID syndrome (PCS) in Germany: A prospective, multi-centre, population-based cohort study. EClinicalMedicine. 2022 Jul 18;51:101549. doi: 10.1016/j.eclinm.2022.101549. eCollection 2022 Sep.
- Derived from this study: PubMed 42625188Wallraven T, Gunthner R, Lethen I, Ribeiro A, Lech M, Oertel FC, Reess LG, Haller B, Streese L, Hanssen H, Basta-Wunderle M, Schmaderer C. Microvascular remodeling and endothelial dysfunction across the post-COVID-19 spectrum: a prospective observational case-control study. BMC Med. 2026 Aug 19;24(1):456. doi: 10.1186/s12916-026-05144-9.
- Derived from this study: PubMed 42415070Wunderle M, Ribeiro A, Lethen I, Schmaderer C, Wallraven T. Persistent impairments in muscle function and symptom burden in post-COVID syndrome: a prospective longitudinal study. J Transl Med. 2026 Jul 7;24(1):871. doi: 10.1186/s12967-026-08579-z.
- Derived from this study: PubMed 38041762Kuchler T, Hausinger R, Braunisch MC, Gunthner R, Wicklein R, Knier B, Bleidissel N, Maier M, Ribero A, Lech M, Adorjan K, Stubbe H, Kotliar K, Heemann U, Schmaderer C. All eyes on PCS: analysis of the retinal microvasculature in patients with post-COVID syndrome-study protocol of a 1 year prospective case-control study. Eur Arch Psychiatry Clin Neurosci. 2024 Dec;274(8):1847-1856. doi: 10.1007/s00406-023-01724-5. Epub 2023 Dec 2.
- Derived from this study: PubMed 37507580Kuchler T, Gunthner R, Ribeiro A, Hausinger R, Streese L, Wohnl A, Kesseler V, Negele J, Assali T, Carbajo-Lozoya J, Lech M, Schneider H, Adorjan K, Stubbe HC, Hanssen H, Kotliar K, Haller B, Heemann U, Schmaderer C. Persistent endothelial dysfunction in post-COVID-19 syndrome and its associations with symptom severity and chronic inflammation. Angiogenesis. 2023 Nov;26(4):547-563. doi: 10.1007/s10456-023-09885-6. Epub 2023 Jul 28.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Christoph Schmaderer, Prof. Dr. principal investigator
Technical University Munich
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Long Covid19 and Post COVID-19 Condition, run by Technical University of Munich at 1 site in Germany.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 9 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: status not confirmed, as of the sponsor's last update on 2 Dec 2022. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Germany. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
Results are not available in the source record.
How can a doctor refer a patient or contact the research team?
Contact Christoph Schmaderer, Prof. Dr. (089 4140 5053, christoph.schmaderer@mri.tum.de), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
PCS patients show an impaired retinal vessel responsiveness when compared with fully recovered COVID-19 participants. (time frame: Baseline). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT05635552, which also lists 5 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 2 Dec 2022.