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

Effect of thoracic epidural analgesia on refractory angina pectoris: long-term home self-treatment

OBJECTIVES

To evaluate the effects of long-term home self-treatment with thoracic epidural analgesia (TEA) on angina, quality of life, and safety.

DESIGN

Prospective consecutive pilot study.

SETTING

Department of Cardiology, Heart Center, Linköping University Hospital.

PARTICIPANTS

Between January 1998 and January 2000, 37 consecutive patients with refractory angina began treatment with TEA, using a subcutaneously tunnelled epidural catheter.

INTERVENTIONS

The patients were trained to provide self-treatment at home with intermittent injections of bupivacaine. Data were collected until January 2001, and the follow-up for each patient was 1 to 3 years.

MEASUREMENTS AND MAIN RESULTS

All but 1 of the patients improved symptomatically. The improvement was maintained throughout the treatment period (4 days to 3 years). The Canadian Cardiovascular Society angina class decreased from 3.6 to 1.7, frequency of anginal attacks decreased from 46 to 7 a week, nitroglycerin intake decreased from 32 to 5 a week, and the overall self-rated quality of life assessed by visual analog scale increased from 24 to 76 (all p < 0.001). No serious catheter-related complications occurred; however, 51% of the catheters became displaced and a new one had to be inserted during the study.

CONCLUSION

Long-term self-administered home treatment with TEA seems to be an effective and safe adjuvant treatment for patients with refractory angina. It produces symptomatic relief of angina and improves the quality of life.

35 years of experimental research in transmyocardial revascularization: what have we learned?

In the past 35 years many experimental studies have been performed to investigate the revascularization potential of transmyocardial revascularization and the possible working mechanisms underlying the observed clinical improvement in angina pectoris after this treatment. In this review of the experimental literature, the various methods that have been used to create transmyocardial channels and the most supported hypotheses on the working mechanism (channel patency, angiogenesis and myocardial denervation) are discussed and evaluated.

Thoracic epidural anesthesia for cardiac surgery: the effects on tracheal intubation time and length of hospital stay

Improvements in analgesia after major surgery may allow a more rapid recovery and shorter hospital stay. We performed a prospective randomized trial to study the effects of epidural analgesia on the length of hospital stay after coronary artery surgery. The anesthetic technique and postoperative mobilization were altered to facilitate early intensive care discharge and hospital discharge. Fifty patients received high (T1 to T4) thoracic epidural anesthesia (TEA) with ropivacaine 1% (4-mL bolus, 3-5 mL/h infusion), with fentanyl (100-microg bolus, 15-25 microg/h infusion) and a propofol infusion (6 mg x kg(-1) x h(-1)). Another 50 patients (the General Anesthesia group) received fentanyl 15 microg/kg and propofol (5 mg x kg(-1) x h(-1)), followed by IV morphine patient-controlled analgesia. The TEA group had lower visual analog scores with coughing postextubation (median, 0 vs 26 mm; P < 0.0001) and were extubated earlier (median hours [interquartile range], 3.2 [2.1-4.6] vs 6.7 [3.3-13.2]; P < 0.0001). More than half of all patients were discharged home on Postoperative Day 4 (24%) or 5 (33%), but there was no difference in the length of stay between the TEA group (median [interquartile range], Day 5 [5-6]) and the General Anesthesia group (median [interquartile range], Day 5 [4-7]). There were no differences in postoperative spirometry or chest radiograph changes or in markers for postoperative myocardial ischemia or infarction. No significant TEA-related complications occurred. In summary, TEA provided better analgesia and allowed earlier tracheal extubation but did not reduce the length of hospital stay after coronary artery surgery.

IMPLICATIONS

We found that epidural analgesia was more effective than IV morphine for cardiac surgery. Epidural anesthesia also allowed earlier weaning from mechanical ventilation, but it did not affect hospital discharge time.

Minimizing perioperative adverse events in the elderly

Elderly patients still have the highest postoperative mortality and morbidity rate in the adult surgical population. Preoperative clinical assessment to detect patients at high risk of postoperative events, and specific intraoperative and postoperative anaesthesia management are important to minimize postoperative adverse events in the elderly.

Regional anaesthesia in patients at coronary risk for noncardiac and cardiac surgery

This review presents a brief overview about the role of regional anaesthesia in patients at risk for myocardial ischemia and/or infarction after cardiac and noncardiac surgical procedures. It includes pathophysiological insights in the problems of plaque rupture and the possible interactions by the use of regional anaesthesia. Special emphasis is put on the subject of thoracic epidural anaesthesia with newer studies showing improvement in relief of angina and improvement of global systolic and diastolic function in patients with coronary artery disease.

Thoracic epidural analgesia: its role in postthoracotomy atrial arrhythmias

OBJECTIVE

To determine the effects of thoracic epidural analgesia (TEA) management on the incidence of atrial arrhythmias (AAs) after thoracotomy for lung resection.

DESIGN

Retrospective.

SETTING

A major university medical center.

PARTICIPANTS

The medical records of 185 consecutive patients who underwent thoracotomy between 1993 and 1997 were reviewed; patients with TEA only were included in the analysis.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

There was a 20% incidence of AAs after thoracotomy. Preoperative predictors of AAs were age >65 years, cardiac history, and an abnormal electrocardiogram (ECG). There was a temporal relationship between epidural catheter removal and occurrence of AAs. Fourteen patients developed AAs before TEA catheter removal, whereas 29 patients developed AAs after TEA catheter removal (p = 0.01). There was no relationship between anatomic site of epidural catheter placement or choice of epidural agent and AAs.

CONCLUSIONS

AAs after thoracotomy were common. These AAs were associated with increased age, cardiac history, abnormal ECG, increased cost, increased length of hospital stay, and time of epidural catheter removal. Although a cause-and-effect relationship cannot be inferred from this study, the presence or absence of TEA was found to have a temporal relationship with the incidence of AAs.

Epidural infusion of bupivacaine and fentanyl reduces perioperative myocardial ischaemia in elderly patients with hip fracture--a randomized controlled trial

BACKGROUND

Perioperative myocardial ischaemia is an important risk factor for cardiac morbidity and mortality after noncardiac surgery. The impact of analgesic management on the incidence and severity of cardiac ischemia was studied in 77 elderly patients undergoing surgical treatment of traumatic hip fracture.

METHODS

After hospital admission and written consent, patients were randomised to conventional analgesic regimen (intramuscular oxycodone, OPI group) or continuous epidural infusion of bupivacaine/fentanyl (EPI group). The analgesic regimens were started preoperatively. Patients were operated under spinal anaesthesia and the treatments were continued three days postoperatively. ECG was continuously recorded. ST segment depression of > or = 0.1 mV or elevation of > or = 0.2 mV lasting > or = 1 min were considered as ischaemic episodes. Nocturnal arterial oxygen saturation (SaO2) was recorded perioperatively, and subjective pain was assessed every morning using a visual analogue scale (VAS).

RESULTS

Fifty-nine (OPI 30, EPI 29) patients were evaluable for efficacy. Thirteen patients (43%) in the OPI and 12 patients (41%) in the EPI group had ischaemic episodes (NS). However, significantly more patients in the OPI group had ischaemic episodes during the surgery (8 vs. 0 in the EPI group, P=0.005). The median (quartal deviation) total ischaemic burden (i.e. integral of ST-change vs. time) in patients with ischaemic episodes was ten times larger in the OPI group (340 [342] mm x min) compared with the EPI group (30 [36] mm x min) (P=0.002). There were no significant differences between the groups in average heart rates or in heart rates at the start of ischaemic episodes or in maximal heart rates during the attacks. Average nocturnal SaO2 was similar in the two groups and there were no differences in the number of hypoxaemic (SaO2<90%) episodes. Preoperatively there were no differences in subjective pain, but postoperative and average perioperative VAS scores for pain were almost 40% lower in the EPI group (P=0.006). Perioperative myocardial infarctions were not detected.

CONCLUSIONS

Continuous epidural bupivacaine/fentanyl analgesic regimen, started preoperatively, reduces the amount of myocardial ischaemia in elderly patients with hip fracture.

Thoracic epidural anesthesia reduces infarct size in a canine model of myocardial ischemia and reperfusion injury

OBJECTIVE

To determine the effects of thoracic epidural anesthesia on myocardial infarct size, regional myocardial blood flow (RMBF), and plasma norepinephrine in an anesthetized canine model of ischemia reperfusion injury with infarction.

DESIGN

Blinded, randomized, placebo-controlled animal study.

SETTING

Experiments were performed in the cardiothoracic research laboratory at Wake Forest University Baptist Medical Center.

PARTICIPANTS

Anesthetized, open-chest mongrel dogs were used in these studies.

METHODS

Dogs were instrumented for measurement of aortic pressure (AP) and left ventricular systolic pressure (LVSP), dP/dt, and RMBF Epidural catheters were inserted at thoracic segment T5. Three groups received epidural 0.5% bupivacaine: low-dose (n = 7; 0.3 mg/kg bolus, 0.15 mg/kg/ h), mid-dose (n = 7; 0.6 mg/kg bolus, 0.3 mg/kg/h), high-dose (n = 7; 1.2 mg/kg bolus, 0.6 mg/kg/h). The vehicle (VEH) group received epidural saline. Bolus followed by maintenance infusions began 30 minutes before the onset of ischemia (60 min) and continued through reperfusion (180 min).

RESULTS

Myocardial infarct size was significantly reduced in the high-dose group versus the VEH and low-dose groups (p < 0.05). After initiation of the mid and high dose, AP, LVSP, and dP/dt decreased 7% to 16% (high vVEH; p < 0.05). VEH dogs showed a 130% increase from control in early postischemic RMBF. There was a dose-dependent attenuation in this reflow response: 72%, 31%, and 6% increase in RMBF in the low, mid, and high groups, relative to controls (p < 0.05 high v VEH). Although there was no significant difference in plasma norepinephrine, fewer surges occurred in the high-dose group.

CONCLUSIONS

Thoracic epidural anesthesia reduces infarct size and postischemic hyperemia in a model of ischemia reperfusion injury.

Pain management in cardiothoracic practice

All analgesia regimens have benefits and side effects, and personal expertise can greatly influence the efficacy of regional techniques. A multimodal approach to analgesic management allows physicians to achieve maximum analgesic efficacy while limiting side effects. An appropriate analgesic plan takes into account the extent of pain associated with the type of incision and adjusts this according to each patient's individual needs. As we enter the new millennium, thoracic and cardiac surgery is becoming more innovative, and the life expectancy of people in the first world is constantly increasing. Older people with less physiologic reserve and more multisystem dysfunction are undergoing more major surgical procedures, and adequate pain control in the postoperative period is becoming increasingly important.

Aortic pain

With the exception of the pain of acute aortic dissection, the thoracic aorta is not usually considered as a pain-producing organ. However, nineteenth century clinicians considered the aorta as a source of cardiovascular pain in the presence of autopsy-documented inflammatory aortitis, aortic aneurysms, and arterial hypertension, whereas early in the twentieth century, aortic pain reactions were elicited in experimental studies involving distension of the ascending aorta or the application of stimulating substances to the outer surface of the aorta. More recently, increased attention to aortic elastic properties, and to aortic vascular biology at the molecular level refocused interest on the many facets of aortic function beyond that of a simple conduit. The recognition of pain of thoracic aortic origin now extends to patients with progressive aortic syndromes such as aortic intramural hematoma, aortic intimal tears, aortic penetrating ulcers, aortic root dilatation without dissection in connective tissue disorders, inflammatory aortopathies, and abnormalities of aortic distensibility. The occurrence of pain during balloon inflation at balloon angioplasty of aortic coarctation, which disappears immediately after deflation, is the modern equivalent of the early experimental studies. The authors present a consideration of thoracic aortic pain in light of contemporary concepts in cardiovascular medicine with roots in the rich historical reservoir of information about aortic function and disease.