Recruiting

Cervicothoracic Sympathetic Block

Sponsor:

University Health Network, Toronto

Code:

NCT07468604

Conditions

Autonomic Dysfunction

Eligibility Criteria

Sex: All

Age: 18+

Healthy Volunteers: Not accepted

Interventions

5 mL of 0.25% bupivacaine with epinephrine (1:200,000)

Sham Group

Study Details

Brief summary:

Post-COVID Condition (PCC) affects roughly 2.1 million Canadians, carrying an annual economic burden of CAD $7.8-50.6 billion. It presents across multiple organ systems with symptoms including fatigue, brain fog, palpitations, and orthostatic intolerance, at an annual cost of CAD $1,675-$7,340 per case.

A key mechanism underlying many treatment-resistant PCC symptoms appears to be dysautonomia abnormal autonomic nervous system function driven by immune-mediated sympathetic overactivity. Persistent inflammation (cytokine storms, T/B-cell dysfunction, microclots) sustains sympathetic hyperactivity, which in turn perpetuates systemic inflammation and "sickness behaviors" resembling PCC symptoms.

Current treatments including beta blockers, ivabradine, fludrocortisone, and rehabilitation are limited by variable responses, side effects, and the complication of post-exertional symptom exacerbation. Emerging therapies (SSRIs, low-dose naltrexone, antihistamines, HBOT) show promise but lack robust trial evidence.

Cervicothoracic sympathetic chain block (CSB) a local anesthetic block of the cervical and upper thoracic sympathetic ganglia is a promising intervention that reduces sympathetic outflow, improves cerebral blood supply, and lowers pro-inflammatory cytokines. Small observational studies (16 studies, 224 patients) show benefit for PCC symptoms, but all lack placebo controls and have significant methodological heterogeneity.

The proposed study aims to fill this gap with a double-blind, placebo-controlled RCT to rigorously evaluate CSB's efficacy, magnitude of benefit, and durability in PCC patients.

Conditions

Autonomic Dysfunction

Study ID

NCT07468604

Start date

May 19, 2026

Status verified date

Jun, 2026

Completion date

Sep 1, 2027

Anticipated

Primary completion date

May 20, 2027

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 18+

Healthy Volunteers: Not accepted

Inclusion criteria

1. Age 18 years or older
2. PCC following COVID-19 infection with symptoms lasting for at least three months
3. Ability to read, write, and understand English
4. Quantified autonomic symptoms from at least one domain as reported by the patient on the screener Composite Autonomic Symptom Score (COMPASS-31), i.e. a COMPASS-31 score greater than 0. COMPASS-31 assesses 6 domains of autonomic symptoms: Orthostatic Intolerance, Vasomotor, Secretomotor, Gastrointestinal, Bladder, and Pupillomotor.
5. Patients should be stable on any PCC-related medications for at least four weeks.

Exclusion criteria

1. History of co-existing conditions that are a contraindication for SGBCSBCSB:

1. Unilateral vocal cord paralysis; Severe chronic obstructive pulmonary disease (FEV1 between 30-50% of predicted value)
2. Recent myocardial infarction (within the last one year), Cardiac conduction block of any degree
3. Glaucoma
4. Infection or mass at injection site, bleeding disorders
2. Comorbid conditions that could confound study results, such as:

1. Active autoimmune disorders
2. Pre-existing autonomic dysfunction (e.g. POTS, IST, and CRPS) prior to COVID-19
3. Untreated psychiatric conditions (e.g. severe anxiety or PTSD requiring medication adjustments during the study period)
3. Recent history of major surgery or cerebrovascular events within the last three months
4. Allergy to local anesthetic; Inability to extend the neck for any reason (e.g. severe arthritis)
5. History of prior stellate ganglion block

Study Design

Enrollment

78 participants

Anticipated

Allocation

Randomized

Intervention Model

Parallel Assignment

Primary purpose

Treatment

Interventions and Outcome Measures

Arms

experimental: Active group

The active group will have cervical sympathetic block (CSB) on both the left and right sides using up to 5 mL of 0.25% bupivacaine with epinephrine (1:200,000).

placebo comparator: Sham group

The sham group will have cervical sympathetic block (CSB) on both the left and right sides using up to 5 ml of normal saline (0.9% NaCl).

Interventions

5 mL of 0.25% bupivacaine with epinephrine (1:200,000)

The active group will have cervical sympathetic block (CSB) on both the left and right sides using up to 5 mL of 0.25% bupivacaine with epinephrine (1:200,000). After the injection, all patients will be monitored for a minimum of 30 minutes to check for expected effects of the block and to watch for any side effects or complications.

Sham Group

The sham group will have cervical sympathetic block (CSB) on both the left and right sides using up to 5 ml of normal saline (0.9% NaCl). After the injection, all patients will be monitored for a minimum of 30 minutes to check for expected effects of the block and to watch for any side effects or complications.

Primary outcome measure

  • Cardiac dysautonomia-related symptoms [ Time Frame: 4-week ]
  • Cardiac dysautonomia-related symptoms [ Time Frame: 4-Week ]

Central Contacts and Locations

Central contacts

Emad Al Azazi, MD, PhD

4166035800emad.al-azazi@uhn.ca

Locations

Toronto Western Hospital

Recruiting

Toronto, Ontario, Canada, M5T 2S8

Contacts

Anuj Bhatia, MD FRCPC

(416) 603 5800anuj.bhatia@uhn.ca

Danielle Alvares

(416) 603 5800danielle.alvares@uhn.ca

Toronto Western Hospital/UHN

Recruiting

Toronto, Ontario, Canada

Contacts

Emad Al Azazi, MD,PhD

4166035800emad.al-azazi@uhn.ca

More Information

Sponsor

University Health Network, Toronto

Last update posted

Jun 8, 2026

Last verified

Jun, 2026

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-10. This information was provided to ClinicalTrials.gov by University Health Network, Toronto on 2026-06-08.