Study to Evaluate the Effectiveness of SGB in Preventing Post-op Atrial Fibrillation
| Status: | Not yet recruiting |
|---|---|
| Conditions: | Atrial Fibrillation |
| Therapuetic Areas: | Cardiology / Vascular Diseases |
| Healthy: | No |
| Age Range: | 18 - Any |
| Updated: | 9/1/2017 |
| Start Date: | December 2017 |
| End Date: | December 2018 |
| Contact: | Janelle Richard, BA, CCRP |
| Email: | richaj3@mmc.org |
| Phone: | 207-662-2862 |
Study for the Evaluation of the Effectiveness of Stellate Ganglion Blockade in Preventing Postoperative Atrial Fibrillation
Atrial fibrillation requires both an initiation trigger and favorable environment for
maintenance and the sympathetic and parasympathetic nervous systems play important roles in
this regard. Unfortunately, the precise mechanisms of post operative atrial fibrillation
(POAF) are still being investigated. This postoperative complication has persisted in spite
of efforts to mitigate it pharmacologically with beta blockers and amiodarone, an experience
shared by most other cardiac surgery centers.
The stellate ganglion is formed by the fusion of the inferior cervical sympathetic ganglion
and first thoracic sympathetic ganglion. By modulating the sympathetic component of the
autonomic nervous system, stellate ganglion stimulation has been shown to facilitate
induction of atrial fibrillation while ablation may reduce or prevent episodes. Human studies
have further supported this model.
Preliminary studies of perioperative stellate ganglion block (SGB) in cardiac surgery suggest
that this technique may reduce or prevent episodes of POAF requiring treatment. The
investigator's hypothesis is that SGB reduces the incidence of POAF in cardiac surgery
populations.
maintenance and the sympathetic and parasympathetic nervous systems play important roles in
this regard. Unfortunately, the precise mechanisms of post operative atrial fibrillation
(POAF) are still being investigated. This postoperative complication has persisted in spite
of efforts to mitigate it pharmacologically with beta blockers and amiodarone, an experience
shared by most other cardiac surgery centers.
The stellate ganglion is formed by the fusion of the inferior cervical sympathetic ganglion
and first thoracic sympathetic ganglion. By modulating the sympathetic component of the
autonomic nervous system, stellate ganglion stimulation has been shown to facilitate
induction of atrial fibrillation while ablation may reduce or prevent episodes. Human studies
have further supported this model.
Preliminary studies of perioperative stellate ganglion block (SGB) in cardiac surgery suggest
that this technique may reduce or prevent episodes of POAF requiring treatment. The
investigator's hypothesis is that SGB reduces the incidence of POAF in cardiac surgery
populations.
The investigator's hypothesis is that perioperative SGB in cardiac surgery will decrease
POAF. To address this, the investigator will:
1. Recruit 707 patients to undergo perioperative SGB prior to cardiac surgery (CABG, Aortic
Valve Replacement, CABG/Aortic Valve Replacement).
2. Perform a double blinded post-induction/pre-operative SGB using either 10 mL 0.5%
bupivacaine or 10 mL 0.9% normal saline
3. Assess the effects on POAF as defined by the Northern New England (NNE) Cardiovascular
Disease Study Group.
Significance: If the investigator is able to demonstrate that perioperative SGB in cardiac
surgery affects POAF, this simple, low cost and low risk procedure may significantly impact
POAF incidence and thereby its attendant morbidity, mortality and costs in this clinical
population.
Study subjects 707 patients electively scheduled for aortic valve, coronary revascularization
surgery (CABG) or a combination of the two (CABG/AVR) will be recruited and enrolled to
receive SGB at the time of surgery. Patients will be introduced to the study by their
surgical team and only those providing informed consent to participate will be enrolled. The
informed consent document (attached) clearly states that SGB is not currently standard of
care.
Randomization The investigator will use NQuery software (Statistical Solutions Ltd., Boston,
MA) to create a randomization scheme stratified by the three types of elective surgery: CABG,
aortic valve replacement, and CABG plus aortic valve replacement. Patients will be randomized
in a 1:1 ratio to receive either SGB (case, injection of 10 mL 0.5% bupivacaine injection) or
sham SGB (control, injection of 10 mL 0.9% saline). For each of the three surgery types,
treatment assignments will be placed in opaque envelopes, numbered sequentially; these three
series of assignments will be maintained in separate surgery-specific boxes. Medications will
be unidentified at the time of injection and the anesthesiologists and cardiac surgeons will
be blinded to sham versus treatment group.
Power analysis:
Sample size was calculated based on a group sequential test of two proportions (NQuery,
Statistical Solutions Ltd., Boston, MA), which takes into account a single interim analysis
of SGB efficacy once 50% of the proposed study group have been enrolled. At 80% power,
cumulative alpha = 0.05, with a two-sided test with continuity correction, and using the
O'Brien-Fleming spending function, a total study group of n=632 (n=316/ treatment group)
would be required to detect a decrease in the rate post-operative atrial fibrillation from
30% to 20% with stellate ganglion block. After taking the interim analysis (performed when
n=350; significance accepted at p<0.003) into account, significance will be accepted at
p<0.047 for the overall study. In our preliminary feasibility study, the investigator
established that stellate ganglion block was successful in 88% of cases; thus, the sample
size was increased by 12%, from n=632 to n=707.
Data analysis. Descriptive statistics (mean (SD), median, frequency as appropriate) will be
used to summarize the demographic, procedural and clinical characteristics of the study
group. To evaluate the success of randomization, the investigator will describe demographic
and clinical data both overall and after stratification by surgery type and by treatment
type. As intra-operative conditions can direct modification in the actual surgery performed
(e.g. CABG may become CABG plus valve replacement), the investigator will also describe the
proportion of subjects who were misclassified by surgery type during randomization and if
necessary will assess randomization balance according to the actual surgery type received.
The frequency of atrial fibrillation (AF) will be compared between treatment groups by chi
square test; this primary analysis will be performed first using an intention to treat model.
In post hoc analysis the investigator will explore treatment outcomes after stratification by
type of surgery and established clinical risk factors for POAF (age, sex, smoking, obesity,
hypertension, diabetes mellitus, myocardial infarction, and BMI). If descriptive analyses
suggest imbalance in clinical or demographic characteristics between treatment groups, these
will be explored using t tests or their non-parametric equivalent (continuous data) or chi
square test (categorical data), as appropriate, and logistic regression will be used to
evaluate differences in AF rate between treatment groups, while taking identified covariates
into account.
POAF. To address this, the investigator will:
1. Recruit 707 patients to undergo perioperative SGB prior to cardiac surgery (CABG, Aortic
Valve Replacement, CABG/Aortic Valve Replacement).
2. Perform a double blinded post-induction/pre-operative SGB using either 10 mL 0.5%
bupivacaine or 10 mL 0.9% normal saline
3. Assess the effects on POAF as defined by the Northern New England (NNE) Cardiovascular
Disease Study Group.
Significance: If the investigator is able to demonstrate that perioperative SGB in cardiac
surgery affects POAF, this simple, low cost and low risk procedure may significantly impact
POAF incidence and thereby its attendant morbidity, mortality and costs in this clinical
population.
Study subjects 707 patients electively scheduled for aortic valve, coronary revascularization
surgery (CABG) or a combination of the two (CABG/AVR) will be recruited and enrolled to
receive SGB at the time of surgery. Patients will be introduced to the study by their
surgical team and only those providing informed consent to participate will be enrolled. The
informed consent document (attached) clearly states that SGB is not currently standard of
care.
Randomization The investigator will use NQuery software (Statistical Solutions Ltd., Boston,
MA) to create a randomization scheme stratified by the three types of elective surgery: CABG,
aortic valve replacement, and CABG plus aortic valve replacement. Patients will be randomized
in a 1:1 ratio to receive either SGB (case, injection of 10 mL 0.5% bupivacaine injection) or
sham SGB (control, injection of 10 mL 0.9% saline). For each of the three surgery types,
treatment assignments will be placed in opaque envelopes, numbered sequentially; these three
series of assignments will be maintained in separate surgery-specific boxes. Medications will
be unidentified at the time of injection and the anesthesiologists and cardiac surgeons will
be blinded to sham versus treatment group.
Power analysis:
Sample size was calculated based on a group sequential test of two proportions (NQuery,
Statistical Solutions Ltd., Boston, MA), which takes into account a single interim analysis
of SGB efficacy once 50% of the proposed study group have been enrolled. At 80% power,
cumulative alpha = 0.05, with a two-sided test with continuity correction, and using the
O'Brien-Fleming spending function, a total study group of n=632 (n=316/ treatment group)
would be required to detect a decrease in the rate post-operative atrial fibrillation from
30% to 20% with stellate ganglion block. After taking the interim analysis (performed when
n=350; significance accepted at p<0.003) into account, significance will be accepted at
p<0.047 for the overall study. In our preliminary feasibility study, the investigator
established that stellate ganglion block was successful in 88% of cases; thus, the sample
size was increased by 12%, from n=632 to n=707.
Data analysis. Descriptive statistics (mean (SD), median, frequency as appropriate) will be
used to summarize the demographic, procedural and clinical characteristics of the study
group. To evaluate the success of randomization, the investigator will describe demographic
and clinical data both overall and after stratification by surgery type and by treatment
type. As intra-operative conditions can direct modification in the actual surgery performed
(e.g. CABG may become CABG plus valve replacement), the investigator will also describe the
proportion of subjects who were misclassified by surgery type during randomization and if
necessary will assess randomization balance according to the actual surgery type received.
The frequency of atrial fibrillation (AF) will be compared between treatment groups by chi
square test; this primary analysis will be performed first using an intention to treat model.
In post hoc analysis the investigator will explore treatment outcomes after stratification by
type of surgery and established clinical risk factors for POAF (age, sex, smoking, obesity,
hypertension, diabetes mellitus, myocardial infarction, and BMI). If descriptive analyses
suggest imbalance in clinical or demographic characteristics between treatment groups, these
will be explored using t tests or their non-parametric equivalent (continuous data) or chi
square test (categorical data), as appropriate, and logistic regression will be used to
evaluate differences in AF rate between treatment groups, while taking identified covariates
into account.
Inclusion Criteria:
- scheduled for non-emergent CABG, AVR, or CABG/AVR
- aged at least 18 years
- English speaking
Exclusion Criteria:
- aged less than 18 years
- pregnant women
- prisoners
- patients having emergency surgery
- patients with clinical contraindications to SGB (including allergy to local
anesthetic, carotid vascular disease as defined by ipsilateral prior carotid
endarterectomy or carotid stent, superficial infection at the proposed puncture site,
contralateral phrenic or laryngeal nerve palsies, and severe chronic obstructive
pulmonary disease as defined by the need for home oxygen)
- patients who are unable to provide informed consent for themselves
- patients with a history of atrial fibrillation
We found this trial at
1
site
22 Bramhall St
Portland, Maine 04102
Portland, Maine 04102
(207) 662-0111
Principal Investigator: Chris Connors, MD
Phone: 207-662-2862
Maine Medical Center One of the country's consistently highest rated hospitals is right in your...
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