The Role of Angina Pectoris in Chronic Pain After Coronary Artery Bypass Graft Surgery

Practice Advisory for Preoperative and Intraoperative Pain Management of Cardiac Surgical Patients: Part 2

Pain after cardiac surgery is of moderate to severe intensity, which increases postoperative distress and health care costs, and affects functional recovery. Opioids have been central agents in treating pain after cardiac surgery for decades. The use of multimodal analgesic strategies can promote effective postoperative pain control and help mitigate opioid exposure. This Practice Advisory is part of a series developed by the Society of Cardiovascular Anesthesiologists (SCA) Quality, Safety, and Leadership (QSL) Committee's Opioid Working Group. It is a systematic review of existing literature for various interventions related to the preoperative and intraoperative pain management of cardiac surgical patients. This Practice Advisory provides recommendations for providers caring for patients undergoing cardiac surgery. This entails developing customized pain management strategies for patients, including preoperative patient evaluation, pain management, and opioid use-focused education as well as perioperative use of multimodal analgesics and regional techniques for various cardiac surgical procedures. The literature related to this field is emerging, and future studies will provide additional guidance on ways to improve clinically meaningful patient outcomes.

Presurgical distress about bodily sensations predicts chronic postsurgical pain intensity and disability 6 months after cardiothoracic surgery

ABSTRACT

Chronic postsurgical pain (CPSP) and disability after cardiothoracic surgery are highly prevalent and difficult to treat. Researchers have explored a variety of presurgical risk factors for CPSP and disability after cardiothoracic surgery, including one study that examined distress from bodily sensations. The current prospective, longitudinal study sought to extend previous research by investigating presurgical distress about bodily sensations as a risk factor for CPSP and disability after cardiothoracic surgery while controlling for several other potential psychosocial predictors. Participants included 543 adults undergoing nonemergency cardiac or thoracic surgery who were followed over 6 months postsurgically. Before surgery, participants completed demographic, clinical, and psychological questionnaires. Six months after surgery, participants reported the intensity of CPSP on a 0 to 10 numeric rating scale and pain disability, measured by the Pain Disability Index. Multinomial logistic regression analyses were conducted to evaluate the degree to which presurgical measures predicted pain outcomes 6 months after surgery. The results showed that CPSP intensity was significantly predicted by age and presurgical scores on the Symptom Checklist-90-Revised Somatization subscale (Nagelkerke R2 = 0.27, P < 0.001), whereas chronic pain disability was only predicted by presurgical Symptom Checklist-90-Revised Somatization scores (Nagelkerke R2 = 0.29, P < 0.001). These findings demonstrate that presurgical distress over bodily sensations predicts greater chronic pain intensity and disability 6 months after cardiothoracic surgery and suggest that presurgical treatment to diminish such distress may prevent or minimize CPSP intensity and disability.

Examination of psychological risk factors for chronic pain following cardiac surgery: protocol for a prospective observational study

INTRODUCTION

Approximately 400 000 Americans and 36 000 Canadians undergo cardiac surgery annually, and up to 56% will develop chronic postsurgical pain (CPSP). The primary aim of this study is to explore the association of pain-related beliefs and gender-based pain expectations on the development of CPSP. Secondary goals are to: (A) explore risk factors for poor functional status and patient-level cost of illness from a societal perspective up to 12 months following cardiac surgery; and (B) determine the impact of CPSP on quality-adjusted life years (QALYs) borne by cardiac surgery, in addition to the incremental cost for one additional QALY gained, among those who develop CPSP compared with those who do not.

METHODS AND ANALYSES

In this prospective cohort study, 1250 adults undergoing cardiac surgery, including coronary artery bypass grafting and open-heart procedures, will be recruited over a 3-year period. Putative risk factors for CPSP will be captured prior to surgery, at postoperative day 3 (in hospital) and day 30 (at home). Outcome data will be collected via telephone interview at 6-month and 12-month follow-up. We will employ generalised estimating equations to model the primary (CPSP) and secondary outcomes (function and cost) while adjusting for prespecified model covariates. QALYs will be estimated by converting data from the Short Form-12 (version 2) to a utility score.

ETHICS AND DISSEMINATION

This protocol has been approved by the responsible bodies at each of the hospital sites, and study enrolment began May 2015. We will disseminate our results through CardiacPain.Net, a web-based knowledge dissemination platform, presentation at international conferences and publications in scientific journals.

TRIAL REGISTRATION NUMBER

NCT01842568.

Technology-Enabled Remote Monitoring and Self-Management - Vision for Patient Empowerment Following Cardiac and Vascular Surgery: User Testing and Randomized Controlled Trial Protocol

Background

Tens of thousands of cardiac and vascular surgeries (CaVS) are performed on seniors in Canada and the United Kingdom each year to improve survival, relieve disease symptoms, and improve health-related quality of life (HRQL). However, chronic postsurgical pain (CPSP), undetected or delayed detection of hemodynamic compromise, complications, and related poor functional status are major problems for substantial numbers of patients during the recovery process. To tackle this problem, we aim to refine and test the effectiveness of an eHealth-enabled service delivery intervention, TecHnology-Enabled remote monitoring and Self-MAnagemenT—VIsion for patient EmpoWerment following Cardiac and VasculaR surgery (THE SMArTVIEW, CoVeRed), which combines remote monitoring, education, and self-management training to optimize recovery outcomes and experience of seniors undergoing CaVS in Canada and the United Kingdom.

Objective

Our objectives are to (1) refine SMArTVIEW via high-fidelity user testing and (2) examine the effectiveness of SMArTVIEW via a randomized controlled trial (RCT).

Methods

CaVS patients and clinicians will engage in two cycles of focus groups and usability testing at each site; feedback will be elicited about expectations and experience of SMArTVIEW, in context. The data will be used to refine the SMArTVIEW eHealth delivery program. Upon transfer to the surgical ward (ie, post-intensive care unit [ICU]), 256 CaVS patients will be reassessed postoperatively and randomly allocated via an interactive Web randomization system to the intervention group or usual care. The SMArTVIEW intervention will run from surgical ward day 2 until 8 weeks following surgery. Outcome assessments will occur on postoperative day 30; at week 8; and at 3, 6, 9, and 12 months. The primary outcome is worst postop pain intensity upon movement in the previous 24 hours (Brief Pain Inventory-Short Form), averaged across the previous 14 days. Secondary outcomes include a composite of postoperative complications related to hemodynamic compromise—death, myocardial infarction, and nonfatal stroke— all-cause mortality and surgical site infections, functional status (Medical Outcomes Study Short Form-12), depressive symptoms (Geriatric Depression Scale), health service utilization-related costs (health service utilization data from the Institute for Clinical Evaluative Sciences data repository), and patient-level cost of recovery (Ambulatory Home Care Record). A linear mixed model will be used to assess the effects of the intervention on the primary outcome, with an a priori contrast of weekly average worst pain intensity upon movement to evaluate the primary endpoint of pain at 8 weeks postoperation. We will also examine the incremental cost of the intervention compared to usual care using a regression model to estimate the difference in expected health care costs between groups.

Results

Study start-up is underway and usability testing is scheduled to begin in the fall of 2016.

Conclusions

Given our experience, dedicated industry partners, and related RCT infrastructure, we are confident we can make a lasting contribution to improving the care of seniors who undergo CaVS.

Postoperative hyperalgesia does not predict persistent post-sternotomy pain; observational study based on clinical examination

BACKGROUND

Persistent post-sternotomy pain is a common problem, but the risk of developing it varies among patients. We sought to find out whether the risk of persistent post-sternotomy pain could be predicted by measuring the area of acute sensory dysfunction around the sternotomy wound. The secondary aim was to determine risk factors for persistent post-sternotomy pain.

PATIENTS AND METHODS

Hundred patients who were scheduled to undergo elective coronary artery bypass surgery were recruited to the study. Patients were excluded if they had undergone previous cardiac surgery or if they lacked co-operation. Preoperative pain scores were determined and the patients filled in questionnaires about depression, anxiety, and pain. The area of sensory dysfunction around the sternotomy wound was assessed by pin prick on postoperative day 4. The presence of persistent post-sternotomy pain was determined at a follow-up evaluation at 4-6 months after surgery.

RESULTS

The sizes of the area of hyperalgesia or overall sensory dysfunction were not associated with persistent post-sternotomy pain. Independent risk factors for persistent post-sternotomy pain were found to be smoking and high pain score on postoperative day 1. The prevalence of persistent post-sternotomy pain in our study population was 38% analyzed by only the questionnaire and 15% according to the clinical examination.

CONCLUSION

Measuring the area of hyperalgesia in the acute phase does not give any additional information on the risk of developing a persistent post-sternotomy pain. We do thus not recommend measuring the area in this particular group of patients. Evaluation of pain by only a questionnaire risks to overestimate the presence of persistent post-sternotomy pain as compared to clinical examination.

Persistent Postoperative Pain after Cardiac Surgery: Incidence, Characterization, Associated Factors and its impact in Quality of Life

BACKGROUND

Cardiac surgery (CS) ranks among the most frequently performed interventions worldwide and persistent postoperative pain (PPP) has been recognized as a relevant clinical outcome in this context. We aimed to evaluate its incidence, characteristics, associated factors and patient's quality of life (QoL).

METHODS

Observational prospective study conducted in patients undergoing CS in a tertiary university hospital. PPP was defined as persistent pain after surgery with higher than 3 months' duration, after excluding other causes of pain. We used a set of questionnaires for data collection: Pain Catastrophizing Scale, Duke Health Profile, Brief Pain Inventory Short Form, McGill Pain Questionnaire Short Form, Douleur Neuropathique en 4 Questions and standardized questions regarding pain periodicity.

RESULTS

A total of 288 patients have completed the study and 43% presented PPP assessed at 3 months (PPP3M); out of which 84% were not under any treatment. PPP patients reported significantly lower QoL, and a neuropathic pain (NP) component was present in 50% of them. Younger age, female gender, higher body mass index, catastrophizing, coronary artery bypass graft, osteoarthritis, history of previous surgery (excluding sternotomy) and moderate to severe acute postoperative pain were independent predictors of PPP3M.

CONCLUSION

This is the first study comprehensively describing PPP after CS and identifying NP in half of them. Our results support the important role that PPP plays after CS in considering its interference in patients' daily life and their lower QoL, which deserves the attention of health care professionals in order to improve prevention, assessment and treatment of these patients. WHAT DOES THIS STUDY ADD?: This study comprehensively describes persistent postoperative pain (PPP) after cardiac surgery (CS) and identifies neuropathic pain (NP) in half of them. Our results support the important role that PPP plays after CS in considering its interference in patients' daily life and their lower quality of life.

Prediction of postoperative pain from assessment of pain induced by venous cannulation and propofol infusion

BACKGROUND

Postoperative pain may lead to delayed mobilization, persisting pain, and psychosocial distress. There are no simple and reliable techniques for prediction of postoperative pain. This study was designed to evaluate if pain induced by venous cannulation or propofol injection can be used to predict postoperative pain.

METHODS

This prospective study included 180 patients scheduled for laparoscopic cholecystectomy. Pain intensity associated with peripheral venous cannulation and administration of propofol preoperatively and pain intensity, and use of opioid postoperatively was recorded.

RESULTS

Patients scoring cannulation-induced pain intensity > 2.0 VAS units were given postoperative opioid more often (65% vs. 36%; P < 0.001), earlier (12 min vs. 90 min; P < 0.001), and in higher doses (4.8 mg vs. 0 mg; P < 0.001), and also reported higher levels of postoperative pain intensity (5.8 vs. 2.9 VAS units; P < 0.001). There were also significant (P < 0.01) correlations with postoperative pain intensity (rs = 0.24), time to opioid administration (rs = -0.26), and total dose of opioid (rs = 0.25). Propofol-induced pain intensity correlated significantly (P < 0.05) with postoperative pain intensity (rs = 0.19).

CONCLUSION

Pain intensity associated with venous cannulation and propofol infusion can easily be evaluated at bedside before surgery without specific equipment or training. Patients scoring > 2.0 VAS units on venous cannulation were found to have 3.4 times higher risk of postoperative pain after laparoscopic cholecystectomy. Low pain intensity associated with venous cannulation and propofol infusion indicate lower risk of postoperative pain.

Risk factors and early pharmacological interventions to prevent chronic postsurgical pain following cardiac surgery

Chronic postsurgical pain (CPSP) after cardiac surgery represents a significant clinical problem. The prevalence of CPSP varies widely between studies, but severe CPSP is present in less than 10% of the patients. Important differential diagnoses for CPSP after cardiac surgery are myocardial ischemia, sternal instability and mediastinitis. CPSP after cardiac surgery may be thoracic pain present at the site of the sternotomy or leg pain due to vein-graft harvesting. The CPSP can be neuropathic pain, visceral pain, somatic pain or mixed pain. Potential risk factors for CPSP are young age, female gender, overweight, psychological factors, preoperative pain, surgery-related factors and severe postoperative pain. In addition to standard postoperative analgesics, the use of N-methyl-D-aspartate (NMDA) antagonists, alpha-2 agonists, local anesthetics, gabapentinoids, and corticosteroids are all proposed to reduce the risk for CPSP after cardiac surgery. Still, no specific pharmacological therapy, cognitive therapy or physical therapy is established to protect against CPSP. The only convincing prevention of CSPS is adequate treatment of acute postoperative pain irrespective of method. Hence, interventions against acute pain, preferably in a step-wise approach titrating the interventions for each patient's individual needs, are essential concerning prevention of CPSP after cardiac surgery. It is also important that surgeons consider the risk for CPSP as a part of the basis for decision-making around performing a surgical procedure and that patients are informed of this risk.

Prevalence of and risk factors for persistent postoperative nonanginal pain after cardiac surgery: a 2-year prospective multicentre study

BACKGROUND

Persistent postoperative pain continues to be an underrecognized complication. We examined the prevalence of and risk factors for this type of pain after cardiac surgery.

METHODS

We enrolled patients scheduled for coronary artery bypass grafting or valve replacement, or both, from Feb. 8, 2005, to Sept. 1, 2009. Validated measures were used to assess (a) preoperative anxiety and depression, tendency to catastrophize in the face of pain, health-related quality of life and presence of persistent pain; (b) pain intensity and interference in the first postoperative week; and (c) presence and intensity of persistent postoperative pain at 3, 6, 12 and 24 months after surgery. The primary outcome was the presence of persistent postoperative pain during 24 months of follow-up.

RESULTS

A total of 1247 patients completed the preoperative assessment. Follow-up retention rates at 3 and 24 months were 84% and 78%, respectively. The prevalence of persistent postoperative pain decreased significantly over time, from 40.1% at 3 months to 22.1% at 6 months, 16.5% at 12 months and 9.5% at 24 months; the pain was rated as moderate to severe in 3.6% at 24 months. Acute postoperative pain predicted both the presence and severity of persistent postoperative pain. The more intense the pain during the first week after surgery and the more it interfered with functioning, the more likely the patients were to report persistent postoperative pain. Pre-existing persistent pain and increased preoperative anxiety also predicted the presence of persistent postoperative pain.

INTERPRETATION

Persistent postoperative pain of nonanginal origin after cardiac surgery affected a substantial proportion of the study population. Future research is needed to determine whether interventions to modify certain risk factors, such as preoperative anxiety and the severity of pain before and immediately after surgery, may help to minimize or prevent persistent postoperative pain.

Chronic pain after cardiac surgery: a prospective study

BACKGROUND

Chronic pain is a complication of several surgical procedures. The prevalence of chronic pain reported after cardiac surgery varies from 18% to 61%. However, most studies are retrospective, do not use validated instruments for pain measurement or include only pain at the sternum site. The aim of the present study was to assess chronic pain and health-related quality of life (HRQOL) after cardiac surgery.

METHODS

In a prospective, population-based study, we included 534 patients (413 males) and assessed chronic pain and HRQOL before, 6 months after, and 12 months after cardiac surgery. Pain was measured by the Brief Pain Inventory, while HRQOL was measured by the Short-Form 36 (SF-36).

RESULTS

Five hundred and twenty-one patients were alive 12 months after surgery; 462 (89%) and 465 (89%) responded after 6 and 12 months, respectively. Chronic pain was reported by 11% of the patients at both measurements. Younger age was associated with chronic pain [odds ratio 0.7 (95% confidence interval: 0.5-0.9)] at 12 months. Patients with chronic pain reported lower scores on seven of eight SF-36 subscales.

DISCUSSION

In conclusion, we observed a lower prevalence of chronic pain after cardiac surgery than in previous studies. Still, more than one out of 10 patients reported chronic pain after cardiac surgery. Chronic pain appears to affect HRQOL. Thus, given the large number of patients subjected to cardiac surgery, this study confirms that chronic pain after cardiac surgery is an important health care issue.

Only half of the chronic pain after thoracic surgery shows a neuropathic component

Chronic pain is a common complication after thoracic surgery. The cause of chronic post-thoracotomy pain is often suggested to be intercostal nerve damage. Thus chronic pain after thoracic surgery should have an important neuropathic component. The present study investigated the prevalence of the neuropathic component in chronic pain after thoracic surgery. Furthermore, we looked for predictive factors for prevalence and intensity of chronic pain. We contacted 243 patients who underwent a video-assisted thoracoscopy (VATS) or thoracotomy in the period between January 2004 and September 2006 by mail. Patients retrospectively received a questionnaire with the Dutch version of the PainDETECT Questionnaire, a validated screening tool for neuropathic pain. Results were analyzed from 204 patients (144 thoracotomies, 60 VATS). The prevalence of chronic pain was 40% after thoracotomy and 47% after VATS. Definite chronic neuropathic pain was present in 23% of the patients with chronic pain, with an additional 30% having probable neuropathic pain. Greater probability of neuropathic pain (ie, a higher total score of the PainDETECT) correlated with more intense chronic pain. Predictive factors for chronic pain were younger age (P = .01), radiotherapy (P = .043), pleurectomy (P = .04) and more extensive surgery (P < .001).

PERSPECTIVE

Up to half the chronic pain after thoracic surgery is not associated with a neuropathic component, which has not been reported to date. More extensive surgery and pleurectomy are predictive factors for chronic pain after thoracic surgery, suggesting a visceral component apart from nerve injury.