BRS and Outcomes in Cardiothoracic Surgery

Study Overview
=================
Brief Summary
-----------------
The purpose of this study is to determine whether baroreceptor sensitivity (the ability of your body to change your heart rate and/or blood pressure in response to a situation) has any effect on how likely you are to suffer certain events after heart or lung surgery. The postoperative events that the investigators will be studying are pain after surgery, atrial fibrillation (an irregular heart rhythm), and cognitive dysfunction (a decline in mental abilities).

Detailed Description
-----------------
The purpose of this study is to determine if preoperative baroreceptor sensitivity (BRS) correlates with major outcomes after cardiac and thoracic surgery, including acute and chronic pain, atrial arrhythmias, and cognitive function. To test this hypothesis, approximately 95 patients will be enrolled, and spontaneous baroreceptor sensitivity will be measured prior to surgery as well as immediately postoperatively. Outcomes will include acute pain using the numeric rating scale, Brief Pain Inventory, and Gracely Box Scale administered preoperatively, on postoperative days 1 and 2 and by phone at 6-weeks postoperatively. Chronic pain will be assessed at 6-month follow-up visit via hyperalgesia testing using Von Frey filaments. Postoperative atrial arrhythmias will be assessed by review of postoperative telemetry, the electronic medical record, and ECG performed prior to discharge. Finally, cognitive function will be assess via Mini-Mental State examination administered preoperative and at the 6-month follow-up visit. Association between BRS and the outcomes of interest will be tested with regression models adjusted for appropriate covariates. Significance threshold alpha will be adjusted for the number of statistical tests using the Bonferroni correction. Our hypothesis is that patients with impaired preoperative BRS will have an increased incidence of acute and chronic postoperative pain, atrial fibrillation, and cognitive decline after surgery.

Official Title
-----------------
Role of Preoperative Baroreflex Sensitivity on Major Outcomes After Cardiothoracic Surgery

Conditions
-----------------
Pain, Postoperative, Atrial Fibrillation, Cognitive Dysfunction

Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: >= 18 years of age Undergoing cardiac (coronary artery bypass grafting [CABG], CABG + valve, or valve only) or thoracic (video-assisted thoracoscopic [VATS] approach to lobectomy) surgery Exclusion Criteria: Any preexisting pain condition (defined as pain of >=3 months duration prior to enrollment) Pain at the time of enrollment interview Need for preoperative analgesics Preexisting chronic or paroxysmal atrial fibrillation Preexisting atrial or ventricular arrhythmia Need for preoperative anti-arrhythmic medication History of symptomatic cerebrovascular disease (e.g., prior stroke) with residual deficits Alcoholism (>2 drinks/day) Psychiatric illness (any clinical diagnosis requiring therapy) Drug abuse (any illicit drug use in the preceding 3 months before surgery) Hepatic insufficiency (liver function tests > 1.5 times the upper limit of normal) Severe pulmonary insufficiency (home oxygen) Renal failure (serum creatinine >2.0 mg/dL) Non-English speaking Unable to read Participants who score <24 on baseline Mini Mental State examination

Ages Eligible for Study
-----------------
Minimum Age: 18 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Surgical<br>No interventions. Patients undergoing cardiothoracic surgery will be assessed for baroreflex sensitivity and the outcomes of interest. | |

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Baseline baroreflex sensitivity | Non-invasive BRS testing with BIOPAC MP160 | 30 min | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Postoperative day (POD) 1 baroreflex sensitivity | Non-invasive BRS testing with BIOPAC MP160 | 30 min | 
| POD 2 baroreflex sensitivity | Non-invasive BRS testing with BIOPAC MP160 | 30 min | 
| 6 month baroreflex sensitivity | Non-invasive BRS testing with BIOPAC MP160 | 6 months | 
| Acute postoperative pain as assessed by the numeric rating scale (NRS) - 24h | Median NRS pain score in the first 24h after surgery | 24 hours | 
| Acute postoperative pain as assessed by the numeric rating scale (NRS) - 48h | Median NRS pain score in the second 24h after surgery | 48 hours | 
| Acute postoperative pain as assessed by the Gracely Box Scale (GBS) - POD1 | GBS survey on POD 1 | 15 min | 
| Acute postoperative pain as assessed by the Gracely Box Scale (GBS) - POD2 | GBS survey on POD 2 | 15 min | 
| Acute postoperative pain as assessed by the Gracely Box Scale (GBS) - 6 mo | GBS survey at 6 month follow-up visit | 6 months | 
| Chronic pain as assessed by the change in Brief Pain Inventory score | Change from baseline to 6 months postoperatively | Baseline, 6 months | 
| Hyperalgesia | Nociceptive threshold as assessed by Von Frey filament testing at 6 month follow-up | 6 months | 
| Area of hyperalgesia or allodynia | Area surrounding operative incision as assessed by Von Frey filament testing at 6 month follow-up | 6 months | 
| Postoperative atrial fibrillation | Chart review assessment of the occurrence of postoperative atrial fibrillation during hospitalization and up to 6 weeks postoperatively | 6 weeks | 
| Postoperative cognitive change | Change from baseline to 6 months in the Mini Mental Status Exam score | Baseline, 6 months | 
| Baseline psychological distress | As assessed by the Brief Symptom Inventory-18 | 15 min | 
| 6 month psychological distress | As assessed by the Brief Symptom Inventory-18 | 6 months | 
| Baseline frailty | As assessed by the Modified Frailty Index | 10 min |