Anti-ischemic and anti-anginal effects of thoracic epidural anesthesia versus those of conventional medical therapy in the treatment of severe refractory unstable angina pectoris

Impact of spinal or epidural anaesthesia on perioperative outcomes in adult noncardiac surgery: a narrative review of recent evidence

Spinal and epidural anaesthesia and analgesia are important anaesthetic techniques, familiar to all anaesthetists and applied to patients undergoing a range of surgical procedures. Although the immediate effects of a well-conducted neuraxial technique on nociceptive and sympathetic pathways are readily observable in clinical practice, the impact of such techniques on patient-centred perioperative outcomes remains an area of uncertainty and active research. The aim of this review is to present a narrative synthesis of contemporary clinical science on this topic from the most recent 5-year period and summarise the foundational scholarship upon which this research was based. We searched electronic databases for primary research, secondary research, opinion pieces, and guidelines reporting the relationship between neuraxial procedures and standardised perioperative outcomes over the period 2018-2023. Returned citation lists were examined seeking additional studies to contextualise our narrative synthesis of results. Articles were retrieved encompassing the following outcome domains: patient comfort, renal, sepsis and infection, postoperative cancer, cardiovascular, and pulmonary and mortality outcomes. Convincing evidence of the beneficial effect of epidural analgesia on patient comfort after major open thoracoabdominal surgery outcomes was identified. Recent evidence of benefit in the prevention of pulmonary complications and mortality was identified. Despite mechanistic plausibility and supportive observational evidence, there is less certain experimental evidence to support a role for neuraxial techniques impacting on other outcome domains. Evidence of positive impact of neuraxial techniques is best established for the domains of patient comfort, pulmonary complications, and mortality, particularly in the setting of major open thoracoabdominal surgery. Recent evidence does not strongly support a significant impact of neuraxial techniques on cancer, renal, infection, or cardiovascular outcomes after noncardiac surgery in most patient groups.

The effect of erector spinae plane block on arterial grafts in coronary artery bypass grafting

Background

This study aims to evaluate the sympathectomy effects of erector spinae plane block on the diameters and cross-sectional areas of the left and right internal mammary arteries and of the radial arteries.

Methods

This prospective study included a total of 25 patients (14 males, 11 females; median age: 67 years; range, 23 to 75 years) who underwent erector spinae plane block categorized as the American Society of Anesthesiologists Class III and underwent off-pump coronary artery bypass grafting between June 01, 2020 and March 01, 2021. The effects of erector spinae plane block on the diameters and cross-sectional areas of the left and right internal mammary arteries and radial arteries were assessed using ultrasonography images taken both before and 45 min after the procedure, from the third, fourth, and fifth intercostal spaces for the left and right internal mammary arteries and from 3 cm proximal to the wrist for the radial arteries.

Results

The diameters and cross-sectional areas of the left and right internal mammary arteries and radial arteries significantly increased compared to baseline values after the erector spinae plane block (p<0.05). There was no significant difference in the pre- and post-procedural heart rate and mean arterial pressure values (p>0.05).

Conclusion

The bilateral erector spinae plane block, which was performed at the T5 level, provided vasodilatation of the left and right internal mammary arteries and radial arteries without causing any significant difference in the heart rate and mean arterial pressure. These findings indicate that the sympathetic block produced by the erector spinae plane block may facilitate better surgical conditions by preventing arterial spasms. Thus, bilateral erector spinae plane block may be a promising technique to achieve regional anesthesia for off-pump coronary artery bypass grafting.

Pain management after robot-assisted minimally invasive esophagectomy

Background

Adequate pain control after open esophagectomy is associated with reduced complications, earlier recovery and higher patient satisfaction. While further developing surgical procedures like robot-assisted minimally invasive esophagectomy (RAMIE) it is relevant to adapt postoperative pain management. The primary question of this observational survey was whether one of the two standard treatments, thoracic epidural analgesia (TEA) or intravenous patient-controlled analgesia (PCA), is superior for pain control after RAMIE as the optimal pain management for these patients still remains unclear. Use of additional analgesics, changes in forced expiratory volume in 1 s (FEV1), postoperative complications and duration of intensive care and hospital stay were also analyzed.

Methods

This prospective observational pilot study analyzed 50 patients undergoing RAMIE (postoperative PCA with piritramide or TEA using bupivacaine; each n = 25). Patient reported pain using the numeric rating scale score and differences in FEV1 using a micro spirometer were measured at postoperative day 1, 3 and 7. Additional data of secondary endpoints were collected from patient charts.

Results

Key demographics, comorbidity, clinical and operative variables were equivalently distributed. Patients receiving TEA had lower pain scores and a longer-lasting pain relief. Moreover, TEA was an independent predictive variable for reduced length of hospital stay (HR -3.560 (95% CI: -6.838 to -0.282), p = 0.034).

Conclusions

Although RAMIE leads to reduced surgical trauma, a less invasive pain therapy with PCA appears to be inferior compared to TEA in case of sufficient postoperative analgesia and length of hospital stay. According to the results of this observational pilot study analgesia with TEA provided better and longer-lasting pain relief compared to PCA. Further randomized controlled trials should be conducted to evaluate the optimal postoperative analgesic treatment for RAMIE.

Pectoral Fascial Plane Versus Paravertebral Blocks for Minimally Invasive Mitral Valve Surgery Analgesia

OBJECTIVES

This study examined the postoperative analgesic efficacy of single-injection pectoral fascial plane (PECS) II blocks compared to paravertebral blocks for elective robotic mitral valve surgery.

DESIGN

A single-center retrospective study that reported patient and procedural characteristics, postoperative pain scores, and postoperative opioid use for patients undergoing robotic mitral valve surgery.

SETTING

This investigation was performed at a large quaternary referral center.

PARTICIPANTS

Adult patients (age ≥18) admitted to the authors' hospital from January 1, 2016, to August 14, 2020, for elective robotic mitral valve repair who received either a paravertebral or PECS II block for postoperative analgesia.

INTERVENTIONS

Patients received an ultrasound-guided, unilateral paravertebral or PECS II nerve block.

MEASUREMENTS AND MAIN RESULTS

One hundred twenty-three patients received a PECS II block, and 190 patients received a paravertebral block during the study period. The primary outcome measures were average postoperative pain scores and cumulative opioid use. Secondary outcomes included hospital and intensive care unit lengths of stay, need for reoperation, need for antiemetics, surgical wound infection, and atrial fibrillation incidence. Patients receiving the PECS II block required significantly fewer opioids in the immediate postoperative period than the paravertebral block group, and had comparable postoperative pain scores. No increase in adverse outcomes was noted for either group.

CONCLUSIONS

The PECS II block is a safe and highly effective option for regional analgesia for robotic mitral valve surgery, with demonstrated efficacy comparable to the paravertebral block.

Neuromodulation for Ventricular Tachycardia and Atrial Fibrillation: A Clinical Scenario-Based Review

Autonomic dysregulation in cardiovascular disease plays a major role in the pathogenesis of arrhythmias. Cardiac neural control relies on complex feedback loops consisting of efferent and afferent limbs, which carry sympathetic and parasympathetic signals from the brain to the heart and sensory signals from the heart to the brain. Cardiac disease leads to neural remodeling and sympathovagal imbalances with arrhythmogenic effects. Preclinical studies of modulation at central and peripheral levels of the cardiac autonomic nervous system have yielded promising results, leading to early stage clinical studies of these techniques in atrial fibrillation and refractory ventricular arrhythmias, particularly in patients with inherited primary arrhythmia syndromes and structural heart disease. However, significant knowledge gaps in basic cardiac neurophysiology limit the success of these neuromodulatory therapies. This review discusses the recent advances in neuromodulation for cardiac arrhythmia management, with a clinical scenario-based approach aimed at bringing neurocardiology closer to the realm of the clinical electrophysiologist.

Effects of Thoracic Epidural Anesthesia on Neuronal Cardiac Regulation and Cardiac Function

Cardiac sympathetic blockade with high-thoracic epidural anesthesia is considered beneficial in patients undergoing major surgery because it offers protection in ischemic heart disease. Major outcome studies have failed to confirm such a benefit, however. In fact, there is growing concern about potential harm associated with the use of thoracic epidural anesthesia in high-risk patients, although underlying mechanisms have not been identified. Since the latest review on this subject, a number of clinical and experimental studies have provided new information on the complex interaction between thoracic epidural anesthesia–induced sympatholysis and cardiovascular control mechanisms. Perhaps these new insights may help identify conditions in which benefits of thoracic epidural anesthesia may not outweigh potential risks. For example, cardiac sympathectomy with high-thoracic epidural anesthesia decreases right ventricular function and attenuates its capacity to cope with increased right ventricular afterload. Although the clinical significance of this pathophysiologic interaction is unknown at present, it identifies a subgroup of patients with established or pending pulmonary hypertension for whom outcome studies are needed. Other new areas of interest include the impact of thoracic epidural anesthesia–induced sympatholysis on cardiovascular control in conditions associated with increased sympathetic tone, surgical stress, and hemodynamic disruption. It was considered appropriate to collect and analyze all recent scientific information on this subject to provide a comprehensive update on the cardiovascular effects of high-thoracic epidural anesthesia and cardiac sympathectomy in healthy and diseased patients.

Advantages of Epidural Analgesia on Pulmonary Functions in Liver Transplant Donors

OBJECTIVE

Epidural analgesia (EA) has positive effects on anesthetic requirement, blood loss, postoperative analgesia, and pulmonary function tests (PFTs). The purpose of the present study was to investigate the effect of EA on postoperative PFTs in liver transplant donors (LTDs).

METHODS

In the present study, 66 LTDs were classified as total intravenous anesthesia (TIVA) and TIVA+EA groups. Patient's age, sex, body mass index, induction and maintenance dose of propofol (IDP and MDP), operation duration, forced expiratory volume in 1 second (FEV₁), forced vital capacity (FVC), FEV₁/FVC ratio, visual analog scale (VAS), atelectasis scores, and lengths of intensive care unit (ICU) and hospital stays were recorded.

RESULTS

In the TIVA+EA group, IPD, MPD, delta-FEV₁ delta-FVC, VAS for all time, atelectasis score and length of hospital stay were significantly lower than in the TIVA group (P < .001 for all). Whereas VAS at the end of the operation was negatively correlated with delta-FEV₁ and delta-FVC (r² = 0.26 P < .001; r² = 0.41 P < .001; respectively), it was positively correlated with atelectasis score and length of ICU stay (r² = 0.49, P < .001; and r² = 0.41, P < .001; respectively). Atelectasis score was positively correlated with length of ICU stay (r² = 0.86, P < .001).

CONCLUSIONS

Reduced anesthetic requirement, better postoperative analgesia, reduced atelectasis score, and preserved PFTs can be provided with the use of EA in LTDs. Positive effects of EA on anesthesia requirement, pain management and pulmonary function are associated with outcomes.

Treatment of Inoperable Coronary Disease and Refractory Angina: Spinal Stimulators, Epidurals, Gene Therapy, Transmyocardial Laser, and Counterpulsation

Intractable angina from refractory coronary disease is a severe form of myocardial ischemia for which revascularization provides no prognostic benefit. Inoperable coronary disease is also accompanied by a “vicious cycle” of myocardial dystrophy from a chronic alteration of the cardiac sympathetic tone and sensitization of damaged cardiac tissues. Several adjunctive treatments have demonstrated efficacy when revascularization is either unsuccessful or contraindicated. Spinal cord stimulation modifies the neurologic input and output of the heart by delivering a very low dose of electrical current to the dorsal columns of the high thoracic spinal cord. Neural fibers then release CGRP and other endogenous peptides to the coronary circulation reducing myocardial oxygen demand and enhancing vasodilation of collaterals to improve the myocardial blood flow of the most diseased regions of the heart. Randomized study has shown the survival data at five years is comparable to bypass for high-risk patients. Transmyocardial laser revascularization creates small channels into ischemic myocardium in an effort to enhance flow though studies have shown no improvement in prognosis over medical therapy alone. Enhanced external counterpulsation uses noninvasive pneumatic compression of the legs to improve diastolic filling of the coronary vessels and promote development of collateral flow. The compressor regimen requires thirty-five hours of therapy over a seven-week treatment period. Therapeutic angiogenesis requires injection of cytokines to promote neovascularization and improve myocardial perfusion into the regions affected by chronic ischemia. Phase 3 trials are pending. High thoracic epidural blockade produces a rapid and potent sympatholysis, coronary vasodilation and reduced myocardial oxygen demand in refractory coronary disease. This technique can be used as an adjunct to bypass surgery or medical therapy in chronic or acute unstable angina. Epidurals are easy to perform and often available for outpatient or inpatient use. The rapid anti-ischemic effect may complement therapeutic angiogenesis or other interventions with delayed onset to clinical benefit. A new era for interventional and implant cardiology is beginning to emerge as more clinicians, including cardiologists, gradually learn new procedures to safely provide more therapeutic options for patients suffering refractory angina.

Clinical neurocardiology defining the value of neuroscience-based cardiovascular therapeutics

The autonomic nervous system regulates all aspects of normal cardiac function, and is recognized to play a critical role in the pathophysiology of many cardiovascular diseases. As such, the value of neuroscience-based cardiovascular therapeutics is increasingly evident. This White Paper reviews the current state of understanding of human cardiac neuroanatomy, neurophysiology, pathophysiology in specific disease conditions, autonomic testing, risk stratification, and neuromodulatory strategies to mitigate the progression of cardiovascular diseases.

High Thoracic Epidural in Cardiac Anesthesia

High thoracic epidural analgesia (HTEA) offers a distinctive opportunity to enhance postoperative recovery for the thoracic surgery patient. In the modern hospital setting with day of admission surgery, the logistics of insertion of the epidural catheter has become increasingly difficult. The greatest limitation to its use might be the believed increased risk of epidural hematoma associated with anticoagulation during cardiopulmonary bypass. The aim of this review is to give an overview of complications and effect on outcomes with focus on cardiac performance and postoperative glycemic control and kidney function. Patients with epidurals may have improved postoperative pulmonary function and shorter ventilation time, while impact on length of stay in the intensive care unit and hospital is not as evident. HTEA is effective in pain management, attenuates perioperative stress and seems to improve postoperative blood glucose control. Whether HTEA improves recovery and facilitates fast-track is still to be confirmed. With regard to serious postoperative complications, there is evidence of reduction in supraventricular arrhythmias and lower frequency of postoperative acute kidney injury and dialysis. There are some indications of lower short term mortality and frequency of postoperative myocardial infarctions, but only as a combined outcome. The present short-term mortality of 1% to 2% should be compared with the most pessimistic frequency of epidural hematoma being 1 in 4600 patients.

[Cardioprotection by thoracic epidural anesthesia? : meta-analysis]

BACKGROUND

Thoracic epidural analgesia (EDA) is thought to provide cardioprotective effects in patients undergoing noncardiac surgery. The results of two previous meta-analysis showed controversial conclusions regarding the impact of EDA on perioperative survival. The purpose of the present meta-analysis was to evaluate, whether thoracic EDA has the potential to reduce perioperative cardiac morbidity or mortality on the basis of available randomized controlled trials.

PATIENTS AND METHODS

A systematic literature search was conducted in medical databases (Med-Line, EBM-Reviews, Embase, Biosis and Biological Abstracts) and relevant clinical trials including patients undergoing noncardiac surgery were evaluated by two independent investigators. All randomized controlled trials investigating the effects of thoracic EDA on perioperative outcome, published from 1980 up to the end of 2008 were included into this quantitative systematic review. Calculations were performed using the statistics program Review Manager 4.1 using a fixed-effects model.

RESULTS

Nine studies with a total of 2,768 patients were included in the meta-analysis. Thoracic EDA did not reduce perioperative mortality [odds ratio (Peto OR): 1.08; 95% confidence interval (CI) 0.74-1.58]. Patients receiving thoracic EDA demonstrated a tendency to a lower rate of perioperative myocardial infarction. However, this effect of thoracic EDA did not reach statistical significance (Peto OR: 0.65; 95% CI 0.4-1.05).

CONCLUSIONS

The present meta-analysis did not prove any positive influence of thoracic EDA on perioperative in-hospital mortality in patients undergoing noncardiac surgery. Furthermore, it remains questionable if thoracic EDA has the potential to reduce the rate of perioperative myocardial infarction.

Risks and benefits of thoracic epidural anaesthesia

Thoracic epidural anaesthesia (TEA) reduces cardiac and splanchnic sympathetic activity and thereby influences perioperative function of vital organ systems. A recent meta-analysis suggested that TEA decreased postoperative cardiac morbidity and mortality. TEA appears to ameliorate gut injury in major surgery as long as the systemic haemodynamic effects of TEA are adequately controlled. The functional benefit in fast-track and laparoscopic surgery needs to be clarified. Better pain control with TEA is established in a wide range of surgical procedures. In a setting of advanced surgical techniques, fast-track regimens and a low overall event rate, the number needed to treat to prevent one death by TEA is high. The risk of harm by TEA is even lower, and other methods used to control perioperative pain and stress response also carry specific risks. To optimize the risk-benefit balance of TEA, safe time intervals regarding the use of concomitant anticoagulants and consideration of reduced renal function impairing their elimination must be observed. Infection is a rare complication and is associated with better prognosis. Close monitoring and a predefined algorithm for the diagnosis and treatment of spinal compression or infection are crucial to ensure patient safety with TEA. The risk-benefit balance of analgesia by TEA is favourable and should foster clinical use.

[Nonanalgesic effects of thoracic epidural anesthesia]

Thoracic epidural anesthesia, which has been performed since the 1950s, has progressed from being one analgesic technique among others to its present status as the technique of choice for managing pain after major abdominal and thoracic surgery. In addition to providing effective analgesia, the epidural infusion of local anesthetic agents produces a sympathetic block that offers advantages over other types of pain control, particularly with respect to the cardiovascular, respiratory, and gastrointestinal systems. Thoracic epidural anesthesia provides dynamic pain relief, allowing the patient to resume activity early. It also permits early extubation and is associated with fewer postoperative pulmonary complications, shorter duration of paralytic ileus, and a better response to the stress of anesthesia and surgery. However, meta-analyses have not yet demonstrated that postoperative outcomes are improved. This review describes the nonanalgesic effects of thoracic epidural anesthesia.

Effects of high thoracic epidural anesthesia on atrial electrophysiological characteristics and sympathetic nerve sprouting in a canine model of atrial fibrillation

High thoracic epidural anesthesia (HTEA) blocks the afferent and efferent cardiac sympathetic nerve fibers and may affect atrial electrophysiological characteristics and nerve sprouting in patients with atrial fibrillation (AF). In this study, 18 dogs were randomly divided into a control group (n = 6), in which dogs were atrially paced at 400 beats/min for 6 weeks; an HTEA group (n = 6), in which dogs underwent atrial pacing and HTEA for 6 weeks; and a sham-operated group (n = 6), in which dogs underwent the operation but did not receive atrial pacing or HTEA. Electrophysiological examinations were performed in all groups. Cardiac nerves were immunocytochemically stained with anti-growth-associated protein 43 (GAP43) and anti-tyrosine hydroxylase (TH) antibodies. The protein expressions of nerve growth factor (NGF), GAP43 and TH in atrial myocardium were also studied by western blot. In addition, the plasma levels of C-reactive protein (CRP) and norepinephrine, as well as atrial production of superoxide anion (O(2)(·-)) and malondialdehyde, were measured. In the HTEA group, atrial effective refractory period increased (P < 0.05) and AF maintenance decreased (P < 0.01) significantly compared with the control group. The densities of GAP43-positive nerves and TH-positive nerves were significantly lower in the HTEA group compared with the control group. The protein levels of NGF, GAP43 and TH were also lower in the HTEA group compared with the control group. A significant positive correlation between the expressions of NGF and GAP43 (P < 0.01) was observed. A similar correlation was demonstrated for NGF and TH (P < 0.01) in our study. Furthermore, the plasma levels of CRP and norepinephrine, as well as the amount of O(2)(·-) and malondialdehyde produced from myocardium, decreased in the HTEA group compared with the control group. In conclusion, HTEA inhibited electrical and nerve remodeling and reduced the maintenance of AF in a canine AF model, in which process HTEA exhibited anti-inflammatory and antioxidant effects, indicating that, in addition to the efferent cardiac sympathetic nerve, afferent fibers also play an important role in the initiation and/or maintenance of AF.

Immediate extubation versus standard postoperative ventilation: Our experience in on pump open heart surgery

Elective postoperative ventilation in patients undergoing "on pump" open heart surgery has been a standard practice. Ultra fast-track extubation in the operating room is now an accepted technique for "off pump" coronary artery bypass grafting. We tried to incorporate these experiences in on pump open heart surgery and compare the haemodynamic and respiratory parameters in the immediate postoperative period, in patients on standard postoperative ventilation for 8-12 hours. After ethical committee's approval and informed consent were obtained, 72 patients, between 28 and 45 years of age, undergoing on pump open heart surgery, were selected for our study. We followed same standard anaesthetic, cardiopulmonary bypass (CPB) and cardioplegic protocol. Thirty-six patients (Group E) were randomly allocated for immediate extubation following operation, after fulfillment of standard extubation criteria. Those who failed to meet these criteria were not extubated and were excluded from the study. The remaining 36 patients (Group V) were electively ventilated and extubated after 8-12 hours. Standard monitoring for on pump open heart surgery, including bispectral index was done. The demographic data, surgical procedures, preoperative parameters, aortic cross clamp and cardiopulmonary bypass times were comparable in both the groups. Extubation was possible in more than 88% of cases (n=32 out of 36 cases) in Group E and none required reintubation for respiratory insufficiency. Respiratory, haemodynamic parameters and postoperative complications were comparable in both the groups in the postoperative period. Therefore, we can safely conclude that immediate extubation in the operating room after on pump open heart surgery is an alternative acceptable method to avoid postoperative ventilation and its related complications in selected patients.

Perioperative handling of patients on antiplatelet therapy with need for surgery

The widespread use of metal stents and drug-eluting stents has shown the extent to which patients with unstable coronary perfusion depend on antiplatelet drugs, and how their risk of late thrombosis depends on the long-term use of agents such as clopidogrel. It has also been shown that the risk of surgical bleeding, if antiplatelet drugs are continued, is lower than that of coronary thrombosis if they are withdrawn. Thus, except for low-risk settings, the practice of withdrawing antiplatelet drugs 5-10 days prior to surgical procedures should be changed. The following suggestions are meant to provide a guideline in this respect. Most of the current surgical procedures may be performed while on low-dose aspirin treatment. Except when bleeding may occur in closed spaces (e.g. intracranial surgery, spinal surgery in the medullary canal, surgery of the posterior chamber of the eye) or where excessive blood loss is expected, where only clopidogrel should be discontinued; in all other cases the surgical procedures should be carried out in the presence of dual antiplatelet agents (if prescribed). Aspirin may be discontinued only in subjects at low risk of thrombosis, and at high risk of intraoperative bleeding. Operations associated with an expected excessive blood loss should be postponed unless vital. When prescribed for acute coronary syndrome or during stent re-endothelialization, clopidogrel should not be discontinued before a noncardiac procedure. For elective procedures, surgery should be postponed until the end of the indication for clopidogrel. After the operation, clopidogrel should be resumed within the 12-24 h. Cardiac procedures should be postponed for at least 4 days after clopidogrel withdrawal. The thrombotic risk of preoperative withdrawal of antiplatelet drugs overwhelms the benefit of regional or neuraxial blockade. Antiplatelet treatment replacement by heparin or low-molecular weight heparin does not provide protection against the risk of coronary artery or stent thrombosis. Haemostasis requires that at least 20% of circulating platelets have a normal function. As the effects of antiplatelet agents are not reversible by other drugs, fresh platelets are the only manner to rapidly restore normal haemostasis. Aprotinin decreases postoperative bleeding and transfusion rates in patients undergoing CABG and on clopidogrel during the days preceding surgery.

High thoracic epidural analgesia improves left ventricular function in patients with ischemic heart

BACKGROUND

In patients with ischemic heart disease, high thoracic epidural analgesia (HTEA) has been proposed to improve myocardial function. Tissue Doppler Imaging (TDI) is a tool for quantitative determination of myocardial systolic and diastolic velocities and a derivative of TDI is tissue tracking (TT), which allows quantitative assessment of myocardial systolic longitudinal displacement during systole. The purpose of this study was to evaluate the effect of thoracic epidural analgesia on left ventricular (LV) systolic and diastolic function by means of two-dimensional (2D) echocardiography and TDI in patients with ischemic heart disease.

METHODS

The effect of a high epidural block (at least Th1-Th5) on myocardial function in patients (N=15) with ischemic heart disease was evaluated. Simpson's 2D volumetric method was used to quantify LV volume and ejection fraction. Systolic longitudinal displacement was assessed by the TT score index and the diastolic function was evaluated from changes in early (E'') and atrial (A'') peak velocities during diastole.

RESULTS

After HTEA, 2D measures of left ventricle function improved significantly together with the mean TT score index [from 5.87 +/- 1.53 to 6.86 +/- 1.38 (P<0.0003)], reflecting an increase in LV global systolic function and longitudinal systolic displacement. The E''/A'' ratio increased from 0.75 +/- 0.27 to 1.09 +/- 0.32 (P=0.0026), indicating improved relaxation.

CONCLUSION

A 2D-echocardiography in combination with TDI indicates both improved systolic and diastolic function after HTEA in patients with ischemic heart disease.

Perioperative antiplatelet therapy: the case for continuing therapy in patients at risk of myocardial infarction

Recent clinical data show that the risk of coronary thrombosis after antiplatelet drugs withdrawal is much higher than that of surgical bleeding if they are continued. In secondary prevention, aspirin is a lifelong therapy and should never be stopped. Clopidogrel is regarded as mandatory until the coronary stents are fully endothelialized, which takes 3 months for bare metal stents, but up to 1 yr for drug-eluting stents. Therefore, interruption of antiplatelet therapy 10 days before surgery should be revised. After reviewing the data on the use of antiplatelet drugs in cardiology and in surgery, we propose an algorithm for the management of patients, based on the risk of myocardial ischaemia and death compared with that of bleeding, for different types of surgery. Even if large prospective studies with a high degree of evidence are still lacking on different antiplatelet regimens during non-cardiac surgery, we propose that, apart from low coronary risk situations, patients on antiplatelet drugs should continue their treatment throughout surgery, except when bleeding might occur in a closed space. A therapeutic bridge with shorter-acting antiplatelet drugs may be considered.

Transmyocardial Laser Revascularization Enhances Blood Flow within Bypass Grafts

OBJECTIVE

: Early benefits from transmyocardial laser revascularization (TMR) may be related to acute sympathetic denervation. This study hypothesized that TMR as an adjunct to off-pump coronary artery bypass (OPCAB) would improve myocardial runoff in the TMR-treated regions and increase graft flow.

METHODS

: Graft blood flow was measured in 145 consecutive OPCAB patients. In patients with graft flow <40 mL/min (n = 25), the myocardial region served by the graft was treated with TMR. Blood flow was reassessed 10 minutes after TMR and compared with graft flow in the nontreated regions. Postoperative outcomes, transcardiac thrombin production, coagulation activation, myocardial, and inflammatory markers were assessed. A control group not treated with TMR (n = 14) was selected with similar graft flows and other baseline characteristics.

RESULTS

: Risk factors, comorbidities, and preoperative medications were similar in all groups. TMR led to a 48% increase in bypass graft flow in 12 patients, but no significant change in flow in the remainder (n = 13). The control group also showed no change in graft flow measured during the same time-points. Compared with those that did not respond to TMR, responders showed a greater drop in pH during warm ischemia caused by distal anastomoses during OPCAB and significantly higher transcardiac gradients of F1.2, IL-8, TNFα, and VCAM.

CONCLUSIONS

: TMR acutely improves venous bypass graft flow in regions with more severe myocardial acidosis and inflammation during and after OPCAB. Acute sympathetic denervation after TMR may provide mechanistic insight into the early clinical benefits of TMR as an adjunct to OPCAB.

Perioperative use of anti-platelet drugs

Performing a surgical procedure on a patient undergoing anti-platelet therapy raises a dilemma: is it safer to withdraw the drugs and reduce the haemorrhagic risk, or to maintain them and reduce the risk of myocardial ischaemic events? Based on recent clinical data, this review concludes that the risk of coronary thrombosis on anti-platelet drugs withdrawal is much higher than the risk of surgical bleeding when maintaining them. In secondary prevention, aspirin is a lifelong therapy and should never be stopped. Clopidogrel is mandatory as long as the coronary stents are not fully endothelialized, which takes 6-24 weeks depending on the technique used, but might be required for a longer period.

Epidural anesthesia and pulmonary function

The epidural administration of local anesthetics can provide anesthesia without the need for respiratory support or mechanical ventilation. Nevertheless, because of the additional effects of epidural anesthesia on motor function and sympathetic innervation, epidural anesthesia does affect lung function. These effects, i.e., a reduction in vital capacity (VC) and forced expiratory volume in 1 s (FEV(1.0)), are negligible under lumbar and low thoracic epidural anesthesia. Going higher up the vertebral column, these effects can increase up to 20% or 30% of baseline. However, compared with postoperative lung function following abdominal or thoracic surgery without epidural anesthesia, these effects are so small that the beneficial effects still lead to an improvement in postoperative lung function. These results can be explained by an improvement in pain therapy and diaphragmatic function, and by early extubation. In chronic obstructive pulmonary disease (COPD) patients, the use of thoracic epidural anesthesia has raised concerns about respiratory insufficiency due to motor blockade, and the risk of bronchial constriction due to sympathetic blockade. However, even in patients with severe asthma, thoracic epidural anesthesia leads to a decrease of about 10% in VC and FEV(1.0) and no increase in bronchial reactivity. Overall, epidural administration of local anesthetics not only provides excellent anesthesia and analgesia but also improves postoperative outcome and reduces postoperative pulmonary complications compared with anesthesia and analgesia without epidural anesthesia.

Thoracic epidural anesthesia impairs the hemodynamic response to acute pulmonary hypertension by deteriorating right ventricular-pulmonary arterial coupling

OBJECTIVE

Thoracic epidural anesthesia is increasingly used in critically ill patients. This analgesic technique was shown to decrease left ventricular contractility, but effects on right ventricular function have not been reported. A deterioration of right ventricular performance may be clinically relevant for patients with acute pulmonary hypertension, in which right ventricular function is an important determinant of outcome. In the present study, we tested the hypothesis that thoracic epidural anesthesia decreases right ventricular contractility and limits its capacity to tolerate pulmonary hypertension.

DESIGN

Prospective, placebo-controlled study using an established model of acute pulmonary hypertension.

SETTING

University hospital laboratory.

SUBJECTS

A total of 14 pigs (mean weight, 35 +/- 2 kg).

INTERVENTIONS

After instrumentation with an epidural catheter, biventricular conductance catheters, a pulmonary flow probe, and a high-fidelity pulmonary pressure catheter, seven pigs received thoracic epidural anesthesia and seven pigs served as control. Hemodynamic measurements were performed in baseline conditions and after induction of pulmonary hypertension via hypoxic pulmonary vasoconstriction (Fio2 of 0.15).

MEASUREMENTS AND MAIN RESULTS

Ventricular contractility was assessed using load- and heart rate-independent variables. Right ventricular afterload was characterized with instantaneous pressure-flow measurements. In baseline conditions, thoracic epidural anesthesia decreased left but not right ventricular contractility. In untreated animals, pulmonary hypertension was associated with an increase in right ventricular contractility and cardiac output. Pretreatment with thoracic epidural anesthesia completely abolished the positive inotropic response to acute pulmonary hypertension. As a result, ventriculo-vascular coupling between the right ventricle and pulmonary-arterial system deteriorated, and cardiac output was significantly lower in animals with thoracic epidural anesthesia than in untreated controls during hypoxia-induced pulmonary hypertension.

CONCLUSIONS

Thoracic epidural anesthesia inhibits the native positive inotropic response of the right ventricle to increased afterload and deteriorates the hemodynamic effects of acute pulmonary hypertension.

High thoracic epidural blockade increases myocardial oxygen availability in coronary surgery patients

BACKGROUND

High thoracic epidural techniques are increasingly being used in patients scheduled for cardiothoracic surgery, including coronary artery bypass grafting. In the present study, we evaluated the acute effects of the epidural blockade on myocardial oxygen availability by means of tissue oxygen pressure monitoring in patients submitted for surgical revascularization.

METHODS

Fifty adult patients were included in a prospective, randomized, double-blind study. After placement of an epidural catheter in thoracic space T1-T2, and under general anesthesia, 5-10 ml of either normal saline or 0.3% ropivacaine was injected through the epidural catheter. Hemodynamic parameters and the intramyocardial oxygen partial pressure were recorded before and 20 min after the epidural injection.

RESULTS

There were no demographic or hemodynamic differences between the groups before intervention. A significant increase in intramyocardial partial oxygen pressure was observed in the ropivacaine group (14.6 mmHg vs. 25.1 mmHg, P < 0.0005).

CONCLUSION

High thoracic epidural blockade with 5-10 ml of 0.3% ropivacaine increases myocardial oxygen availability in coronary diseased patients prior to surgical revascularization without deleterious hemodynamic disturbances.

High thoracic epidural anesthesia and coronary artery disease in surgical and non-surgical patients

PURPOSE OF REVIEW

Even though high thoracic epidural anesthesia has been shown to be highly efficacious in the control of symptoms in refractory angina, its general use is still restricted. In patients who undergo coronary revascularization, however, the technique is becoming more and more popular. The present review outlines the use of high thoracic epidural anesthesia in patients with ischemic heart disease who underwent coronary revascularization in order to further reveal high thoracic epidural anesthesia's low complication rate and to analyze why physicians still refrain from using it more frequently.

RECENT FINDINGS

The incidence of severe hemodynamic complications after high thoracic epidural anesthesia is low in patients with coronary artery disease. The main advantage would be a myocardial sympathectomy leading to an improvement in the oxygen input-demand relationship. Likewise, a decrease in mortality due to respiratory complications could not be shown. In patients undergoing myocardial revascularization with full anticoagulation there is an increased risk of epidural hematoma formation. Its precise risk is difficult to evaluate. There is an overall low rate of epidural hematomas as a result of high thoracic epidural anesthesia. With the available data, the incidence has been estimated at between 1/1500 and 1/10,000.

SUMMARY

Epidural anesthesia does not decrease mortality or the incidence of myocardial infarction after coronary artery bypass grafting. It reduces the incidence of arrhythmias and respiratory complications and improves the quality of analgesia. High thoracic epidural anesthesia has been shown to be a safe and efficient technique for refractory angina that reduces the frequency of ischemic events and improves the clinical condition of patients.

Continuous intra- and postoperative thoracic epidural analgesia attenuates brain natriuretic peptide release after major abdominal surgery

We investigated whether blocking afferent nociceptive inputs by continuous intra- and postoperative thoracic epidural analgesia (TEA) would decrease plasma concentrations of brain natriuretic peptide (BNP) in patients who were at risk for, or had, coronary artery disease. Twenty-eight patients undergoing major abdominal surgery received either general anesthesia supplemented with a continuous thoracic epidural infusion of 1.25 mg/mL bupivacaine and 1 microg/mL sufentanil (n = 14; TEA) or general anesthesia followed by IV patient-controlled analgesia (n = 14; IV PCA). Visual analog scale pain scores, hemodynamics, plasma catecholamines, cardiac troponin T, atrial natriuretic peptide (ANP), and BNP were serially measured preoperatively, 90 min after skin incision, at arrival in the intensive care unit, and in the morning of the first, second, and third postoperative day. Dynamic visual analog scale scores were significantly less in the TEA group. TEA reduced the postoperative heart rate without affecting other hemodynamic variables. Plasma epinephrine increased perioperatively in both groups but was significantly lower in the TEA group. Baseline ANP and BNP concentrations were similar between groups (TEA 3.4 +/- 1.8 and 27.0 +/- 12.3 pg/mL; IV PCA 3.1 +/- 2.0 and 25.9 +/- 13.0 pg/mL, respectively). ANP and BNP increased perioperatively in both groups, with significantly lower postoperative BNP levels in TEA patients (TEA 92.1 +/- 31.9 pg/mL; IV PCA 161.2 +/- 44.7 pg/mL). No such difference was observed in plasma ANP concentrations. Plasma cardiac troponin T concentrations were within normal limits in both groups at all times. We conclude that continuous perioperative TEA using local anesthetics and opioids attenuated the release of BNP in patients undergoing major abdominal surgery who were at risk for, or had, coronary artery disease.

The effect of high thoracic epidural anesthesia on systolic and diastolic left ventricular function in patients with coronary artery disease

In patients with coronary artery disease, vasoconstriction is induced through activation of the sympathetic nervous system. Both alpha1- and alpha2-adrenergic epicardial and microvascular constriction are potent initiators of myocardial ischemia. Attenuation of ischemia has been observed when sympathetic nervous system activity is inhibited by high thoracic epidural anesthesia (HTEA). However, it is still a matter of controversy whether establishing HTEA may correspondingly translate into an improvement of left ventricular (LV) function. To clarify this issue, LV function was quantified serially before and after HTEA using a new combined systolic/diastolic variable of global LV function (myocardial performance index [MPI]) and additional variables that more specifically address systolic (e.g., fractional area change) or diastolic function (e.g., intraventricular flow propagation velocity [Vp]). High thoracic epidural catheters were inserted in 37 patients scheduled for coronary artery surgery, and HTEA was administered in the awake patients. Echocardiographic and hemodynamic measures were recorded before and after institution of HTEA. HTEA induced a significant improvement in diastolic LV function (e.g., Vp changed from 45.1 +/- 16.1 to 53.8 +/- 18.8 cm/s; P < 0.001), whereas indices of systolic function did not change. The change in the diastolic characteristics caused the MPI to improve from 0.51 +/- 0.13 to 0.35 +/- 0.13 (P < 0.001). We conclude that an improvement in cardiac function was due to improved diastolic characteristics.

Update in thoracic epidural anaesthesia

Thoracic epidural analgesia (TEA) provides optimal perioperative anaesthesia and analgesia after thoracic and major abdominal surgery and decreases postoperative morbidity and mortality, mainly by blocking sympathetic nerve fibres. Surgery leads to a stress response characterized by sympathetic arousal, altered balance of catabolic and anabolic hormones, hypermetabolism, negative protein economy, and altered carbohydrate metabolism and immune function. A threefold increase of the plasma level of norepinephrine (noradrenaline) was detected up to 24 hours after surgery. These elevated catecholamine plasma levels are a risk, especially to patients with coronary artery disease, because unlike healthy coronary arteries, the stress response causes a vasoconstriction in arteriosclerotic coronary arteries. TEA results in a vasodilation in stenotic coronary arteries. In patients with instable angina pectoris, TEA reduced the number as well as the duration of episodes of cardiac ischaemia. Furthermore, TEA improves myocardial structure and function after coronary artery bypass grafting. Plasma levels of troponin T and I, as well as of atrial natriuretic peptides, were reduced and echocardiographic parameters of the ventricular wall motion were improved by TEA. Patients showed fewer arrhythmic episodes and postoperative myocardial infarction, and could be extubated earlier. The positive effects of TEA after coronary artery bypass grafting are not limited to a short postoperative period, the 2-year mortality rate also seems to be reduced. Optimized pain control and early mobilization decrease the riskof pulmonary complications, resulting in a shortened stay in intensive care units. In combination with early enteral nutrition, TEA leads to an earlier return of gastrointestinal function. Patients treated with thoracic epidural anaesthesia and analgesia have a better health-related quality of life.

Regional anesthesia and perioperative outcome: what is new?

PURPOSE OF REVIEW

This review of the most recent publications is aimed to look at the current developments regarding the effects of regional anesthesia on perioperative outcome.

RECENT FINDINGS

The debate continues on whether regional anesthesia and analgesia improve outcome or not. Researchers are still divided in their views. While previous meta-analyses are more favorable, more recent trials are rather on the con side. In an attempt to lessen heterogeneity, meta-analyses have now incorporated data from more recent trials to perform subgroup analyses. Such analyses persistently show the same positive results. The established outcome effects of regional anesthesia are mostly due its ability to provide superior analgesia, its ability to reduce the perioperative stress response and subsequent physiologic perturbations, and its ability to reduce pulmonary complications. Its potential to prevent cardiac morbidity in patients undergoing coronary artery bypass grafting is investigated further by looking at valuable specific biological markers like troponin I and natriuretic peptides. Intrathecal opioids do not seem to improve outcome, unlike the intrathecal local anesthetics. The latter improve outcome presumably by blocking the surgical stress response. In contrast, opioids, non-steroidal antiinflammatory drugs and cyclooxygenase-2 inhibitors have been shown not to impact outcome presumably by not being able to interfere with the stress response. The safety and efficacy of epidural or spinal anesthesia for spinal surgery continue to be demonstrated by current studies.

SUMMARY

Despite the controversies, the numerous potential benefits and advantages of regional anesthesia are keys to its continued popularity. With constant search for new scientific clues by improving experimental designs, valuable evidence slowly unfolds. Regional anesthesia certainly takes a leading role in the current trends for a multimodal approach of perioperative pain management.

High thoracic epidural anesthesia for off-pump coronary artery bypass surgery

OBJECTIVE

To assess the feasibility of high thoracic epidural anesthesia combined with sevoflurane for off-pump coronary artery bypass surgery and to evaluate the postoperative pain control, side effects, and perioperative hemodynamics.

DESIGN

Retrospective review of prospectively collected data.

SETTING

A university teaching hospital.

PARTICIPANTS

One hundred six consecutive patients receiving thoracic epidural combined with sevoflurane.

INTERVENTION

From November 1999, the patients undergoing off-pump coronary artery bypass grafting were offered the epidural-inhalation anesthetic approach.

MEASUREMENTS AND MAIN RESULTS

Insertion of the epidural catheter was successful in all but 2 patients; 1 bloody tap occurred and the dura was never punctured, although 1 patient presented with postoperative paraplegia. An emergency spinal cord nuclear magnetic resonance excluded signs of medullary compression caused by epidural or spinal hematoma. Visual analog scale scores for pain during the first 24-hour period were < 2 in all patients. Mean time to extubation was 4.6 +/- 2.9 hours. The average intensive care unit stay was 1.5 +/- 0.8 days. Incidences of perioperative myocardial infarction, myocardial ischemia, and atrial fibrillation were 2.8%, 7.5%, and 10.6%, respectively. Two patients died: 1 from multiorgan failure and the other from myocardial infarction. Heart rate, mean arterial pressure, cardiac index, and systemic vascular resistance were not affected by thoracic epidural alone. Mean arterial pressure and cardiac index decreased (p < 0.05) when general anesthesia was induced and remained stable thereafter. Neither heart rate nor systemic vascular resistance changed from baseline during operation.

CONCLUSIONS

Thoracic epidural as an adjunct to general anesthesia is a feasible technique in off-pump coronary artery bypass surgery. It induces intense postoperative analgesia and does not compromise central hemodynamics.

Awake coronary artery bypass grafting: utopia or reality?

BACKGROUND

Off-pump coronary artery bypass grafting (OPCAB) was implemented to reduce trauma during surgical coronary revascularization. High thoracic epidural anesthesia further reduced intraoperative stress and postoperative pain. This technique also supports awake coronary artery bypass (ACAB), completely avoiding the drawbacks of mechanical ventilation and general anesthesia in high-risk patients. We compared our first results of the ACAB procedure with the conventional OPCAB operation.

METHODS

Thirty-five patients underwent ACAB (group A) with left internal mammary artery to left anterior descending coronary artery grafting using a partial lower ministernotomy (n = 25) or double bypass grafting (n = 9) and even triple vessel coronary artery revascularization (n = 1) through complete median sternotomy. Thirty-four patients (group B), matched for age, sex, and comorbidity with group A, underwent either partial lower ministernotomy (n = 24) or OPCAB by complete sternotomy (n = 10). We recorded clinical outcomes and postoperative visual analog scale pain scores.

RESULTS

In group A, 32 patients remained awake throughout the entire procedure. Three patients required secondary intubation because of incomplete analgesia (n = 1) or pneumothorax (n = 2). Patients in group A had a recovery room stay of 6.0 +/- 3.2 hours. In group B, mechanical ventilation was implemented for 4.8 +/- 3.1 hours and intensive care unit stay lasted 12 +/- 6.8 hours. Group A had no in-hospital deaths, compared with 1 death in the conventional OPCAB group. Each group had 1 patient with graft stenosis detected on the predischarge angiogram. Early postoperative pain was significantly less in group A than in group B (visual analog scale of 32 +/- 8 compared with 58 +/- 11, p < 0.0001).

CONCLUSIONS

The present data demonstrate the feasibility and safety of surgical coronary revascularization without general anesthesia. Continuation of thoracic epidural analgesia provides better pain control and faster mobilization after such procedures. Surprisingly, the ACAB procedure was well accepted by the patients.