The "natural history" of segmental wall motion abnormalities in patients undergoing noncardiac surgery. S.P.I. Research Group

Perioperative Risk of Noncardiac Surgery in Patients With Asymptomatic Significant Aortic Stenosis: A 10-Year Retrospective Study

BACKGROUND

Aortic stenosis (AS) is a representative geriatric disease, and there is an anticipated rise in the number of patients requiring noncardiac surgeries in patients with AS. However, there is still a lack of research on the primary predictors of noncardiac perioperative complications in patients with asymptomatic significant AS.

METHODS AND RESULTS

Among the cohort of noncardiac surgeries under general anesthesia, with an intermediate to high risk of surgery from 2011 to 2019, at Samsung Medical Center, 221 patients were identified to have asymptomatic significant AS. First, to examine the impact of significant AS on perioperative adverse events, the occurrences of major adverse cardiovascular events and perioperative adverse cardiovascular events were compared between patients with asymptomatic significant AS and the control group. Second, to identify the factors influencing the perioperative adverse events in patients with asymptomatic significant AS, a least absolute shrinkage and selection operator regression model was used. There was no significant difference between the control group and the asymptomatic significant AS group in the event rate of major adverse cardiovascular events (4.6% at control group versus 5.5% at asymptomatic significant AS group; P=0.608) and perioperative adverse cardiovascular events (13.8% at control group versus 18.3% at asymptomatic significant AS group; P=0.130). Cardiac damage stage was a significant risk factor of major adverse cardiovascular events and perioperative adverse cardiovascular events.

CONCLUSIONS

There was no significant difference in major postoperative cardiovascular events between patients with asymptomatic significant AS and the control group. Advanced cardiac damage stage in significant AS is an important factor in perioperative risk of noncardiac surgery.

The patient with ischaemic heart disease undergoing non cardiac surgery

The incidence of ischaemic heart disease (IHD) is increasing. The patients with IHD with or without interventions coming for non-cardiac surgical procedures are also increasing. These patients have increased risk of myocardial ischaemia, myocardial infarction (MI), conduction disturbances, morbidity and mortality during the peri-operative period. The risks of these events are even higher in patients with recent MI. An anaesthesiologist should be aware of the pathophysiology and the need to thoroughly evaluate the patient for peri-operative management. We searched Pubmed using combinations of terms like “ischemic heart disease” and “anaesthesia”, “perioperative”, and “anaesthetic implications”. We reviewed the current practices and guidelines regarding evaluation, risk stratification and management.

How to Reliably Detect Ischemia in the Intensive Care Unit and Operating Room

Detection of myocardial ischemia in the perioperative period is important because it allows for intervention that may prevent progression of ischemia to myocardial infarction. Perioperative ischemia is also an important predictor of adverse cardiovascular outcomes. Patients should first be stratified according to their risk of having cardiovascular disease by identifying major, intermediate, and minor predictors of adverse cardiovascular outcome. Electrocardiographic (ECG) monitoring for ischemia is inexpensive and noninvasive, but may not be applicable to all patients and is not perfectly sensitive or specific. Modern operating room monitors can automate ST segment monitoring and be set to alarm if changes occur. Increases in central venous pressure and pulmonary artery pressure can be caused by myocardial ischemia, but have been shown to be very insensitive compared to ECG. Also, detection of these hemodynamic changes requires insertion of invasive monitoring devices. Transesophageal echocardiography can be used to detect myocardial ischemia by identifying changes in regional wall motion. These transesophageal echocardiography changes occur sooner and more frequently than ECG changes, but require greater knowledge and skill to properly interpret.

Transesophageal echocardiography and noncardiac surgery

The use of transesophageal echocardiography (TEE) for monitoring during cardiac and noncardiac surgery has increased exponentially over the past few decades. TEE has evolved from a diagnostic tool to a monitoring device and a procedural adjunct. The close proximity of the TEE transducer to the heart generates high-quality images of the intracardiac structures and their spatial orientation. The use of TEE in noncardiac and critical care settings is not well studied, and the evidence of the benefits of its use in these settings is lacking. Despite the widespread availability of TEE equipment in US hospitals, less than 30% of anesthesiologists are formally trained in the use of perioperative TEE. In this review, the safety and indications of TEE are reviewed and detailed analysis of the best available evidence in this regard is presented. Landmark trials evaluating the use of TEE and its therapeutic impact in noncardiac surgical setting are critically reviewed. This article details recommendations to familiarize anesthesiologists with TEE technology to exploit it to its fullest potential to achieve better patient monitoring standards and eventually improve outcome. Training of greater numbers of anesthesiologists in TEE is needed to increase awareness of the indications and contraindications. Until relatively inexpensive TEE equipment is available, the initial cost of equipment acquisition remains a significant prohibitive factor limiting its widespread use.

Cardiac risk reduction in non-cardiac surgery: the role of anaesthesia and monitoring techniques

Cardiac complications are the major cause of perioperative morbidity and mortality of patients undergoing non-cardiac surgery. This is related to the frequent presence of underlying coronary artery disease. In the last few decades, attention has focused on preoperative cardiac risk assessment that may help to identify patients at increased cardiac risk for whom cardioprotective medication and, when indicated, coronary revascularization may improve perioperative outcome. On the other hand, less attention was given to the role of anaesthesia and monitoring techniques in the cardiac risk management of high-risk patients undergoing non-cardiac surgery. The aim of this review was to summarize the current evidence from published studies on the effect of the type of anaesthesia and monitoring techniques on perioperative cardiac outcome in non-cardiac surgery.

Anesthésie et réanimation pour chirurgie réglée de l'anévrisme de l'aorte abdominale

OBJECTIVES

Patient scheduled for infrarenal abdominal aortic aneurysm surgery carries a high risk of cardiac or respiratory comorbidity. To outline the perioperative management for these patients.

METHODS

Review of the literature using MesH Terms "abdominal aortic aneurysm", "anesthesia", "analgesia" "critical care" and/or "surgery" in Medline database.

RESULTS

Cardiac preoperative evaluation and management have recently been reviewed. Intermediate and high-risk patients should undergo non-invasive cardiac testing to decide between a preoperative medical strategy (using betablocker+/-statin and aspirin) and an interventional strategy (coronary angioplasty or cardiac surgery). Perioperative myocardial ischaemia should also be investigated by clinical, electrocardiographic and biologic monitoring such as plasmatic troponin Ic dosage. Specific score could also assess the respiratory failure risk preoperatively. Epidural analgesia decreases this risk. There is no evidence that a pharmacological treatment decreases the incidence of acute renal failure after aortic surgery. Endovascular repair is actually recommended for older, higher-risk patients or patients with a hostile abdomen or other technical factors that may complicate standard open repair.

[Preoperative evaluation and perioperative management of patients with increased cardiovascular risk]

Due to the increasing age in western countries, combined with high rates of major surgical interventions in high-risk patients, perioperative reduction of cardiovascular complications becomes increasingly more important for perioperative physicians. After identifying patients with increased perioperative risk, specific interventions need to be considered to reduce their risk for cardiovascular complications, either by perioperative medical therapy or specific treatment options (e.g. coronary intervention). Several trials have demonstrated an effect of perioperative beta-blocker-therapy in reducing cardiovascular complications among high-risk patients. Additionally, several monitoring techniques are effective in detecting cardiovascular complications. Nevertheless, it remains unclear whether they are associated with a measurable improvement of outcome. Based on the ACC/AHA-guidelines, the present review describes a stepwise approach to surgical patients to identify perioperative risks, based on specific patient related risk factors, the kind of surgery and on the specific setting (emergency versus elective surgery). In addition, strategies to reduce perioperative cardiovascular complications are discussed.

Segmental myocardial wall motion during minimally invasive coronary artery bypass grafting using open and endoscopic surgical techniques

Current options for minimally invasive surgical treatment of single-vessel coronary artery disease include beating heart procedures without cardiopulmonary bypass (CPB) via mini-thoracotomy (MIDCAB) and totally endoscopic robot-assisted techniques (TECAB) with CPB. Both procedures are associated with potential myocardial stress before revascularization, such as single-lung ventilation (SLV), temporary coronary artery occlusion, cardiac luxation, intrathoracic carbon dioxide insufflation, and extended CPB and operating time. In this echocardiographic study we sought to evaluate the extent of intraoperative segmental wall motion abnormalities (SWMA) during MIDCAB and TECAB surgery and to identify factors affecting SWMA. Forty-six patients with single-vessel coronary artery disease were studied. Sixteen patients were operated using the MIDCAB technique and 30 patients with TECAB. In both groups sequential transesophageal echocardiograms were recorded during the entire procedure. Hemodynamic data and oxygenation variables were acquired simultaneously. In both groups, mild but obvious perioperative SWMA were identified and noted to increase during the course of the operation. These SWMA were more pronounced in the TECAB group. Independent of operating time, these changes disappeared completely after revascularization. No significant hemodynamic compromise was observed. We conclude that MIDCAB and TECAB techniques are associated with significant perioperative SWMA. The appearance of more profound SWMA in the TECAB group compared with the MIDCAB patients might have been the result of intrathoracic CO(2) insufflation, as SLV was used in both groups. No persistent SWMA or post-CPB SWMA were apparent in either group. More extensive intraoperative ventricular SWMA was detected in the TECAB group, suggesting that a more frequent risk for right ventricular dysfunction may exist during TECAB procedures.

Does intraoperative evaluation of left ventricular contractile reserve predict myocardial viability? A clinical study using dobutamine stress echocardiography in patients undergoing coronary artery bypass graft surgery

To determine the contractile reserve of the left ventricle during reperfusion as a predictor of myocardial viability in patients undergoing coronary artery bypass graft surgery, we measured the response of left ventricular regional wall motion and thickening by using dobutamine stress echocardiography (DSE) after myocardial revascularization. All patients were monitored with radial and pulmonary arterial catheters, transesophageal echocardiography, standard five-lead clinical electrocardiography, and three-channel Holter electrocardiography. Immediately after separation from cardiopulmonary bypass, dobutamine was administered IV starting at 5 microg. kg(-1). min(-1), with increases in rate every 3 min to 10, 20, 30, and 40 microg. kg(-1). min(-1). Within 1 wk after surgery, resting and redistribution thallium-201 myocardial perfusion imaging (thallium studies) was performed to assess the relationship between the intraoperative contractile response and myocardial viability. One-hundred patients completed DSE up to 10 microg. kg(-1). min(-1), and 85 patients received the larger escalating doses of the DSE. Seventy-two patients had postoperative thallium studies. At the completion of the small-dose dobutamine infusion, 689 (97.7%) of 705 segments had a normal response (improvement), and 16 segments (2.3%) had a positive response (deterioration). During large-dose dobutamine infusion, 577 (95.8%) of 602 segments had a normal response, and 25 segments (4.2%) had a positive response. Myocardial segments that had a positive response during large-dose DSE (48%) were more likely to be considered as nonviable on postoperative thallium studies compared with segments that had a normal response (14.7%) (P < 0.00001). By using thallium studies as the reference standard, the sensitivity of DSE was low (31% and 48% for small- and large-dose DSE, respectively) in predicting nonviable myocardium. However, the specificity was higher (86% and 85% for small- and large-dose DSE, respectively). In a separate analysis of patients who developed new regional wall motion abnormalities (RWMA) in the early intraoperative reperfusion period, 15 (75%) of 20 abnormally contracting myocardial segments had normal postoperative thallium studies. Our results demonstrate that a normal response to DSE is highly specific for viable myocardium; however, a positive response to DSE has low sensitivity in predicting nonviable myocardium. The majority of new postbypass regional wall motion abnormalities appear to be related to stunned myocardium.

Automated Cardiac Output Measurement by Transesophageal Color Doppler Echocardiography

Automated cardiac output measurement (ACOM), which integrates digital color Doppler velocities in space and in time, has been validated using transthoracic echocardiography but has not been tested using transesophageal echocardiography (TEE). Therefore, we determined the feasibility of the ACOM method by TEE in 36 patients undergoing cardiovascular surgery. Regions of interest for ACOM were placed within a color sector across the main pulmonary artery (PA), the mitral annulus, and the left ventricular outflow tract. Cardiac output was determined from the PA flow, the mitral flow, and the left ventricular ejection flow at each view using the ACOM method. We compared measurements of cardiac output derived from the ACOM method with measurements simultaneously obtained by thermodilution (TD). In the mitral flow analysis, the values derived from ACOM correlated well with those from TD (R(2) = 0.85; mean difference = 0.01 +/- 0.58 L/min in the 2-chamber view; R(2) = 0.78; mean difference = -0.10 +/- 0.68 L/min in the 4-chamber view). In the PA flow analysis, the values derived from ACOM did not correlate with those from TD (R(2) = 0.30). In the left ventricular outflow tract analysis, it was very difficult to obtain the optimal view (44%) in which color Doppler flow signals adequately appeared. Using the ACOM method, we obtained good correlation and agreement for cardiac output measurements in the mitral flow analysis compared with TD. The ACOM method is a practical and rapid method to measure cardiac output by TEE analysis of mitral flow.

IMPLICATIONS

Automated cardiac output measurement by transesophageal color Doppler echocardiography is a practical and rapid method to measure cardiac output. This technique is a promising new approach to echocardiographic quantification in the intraoperative setting.

Therapeutic impact of intra-operative transoesophageal echocardiography during noncardiac surgery

The impact of transoesophageal echocardiography on haemodynamic management during elective noncardiac surgery was assessed during this observational prospective database analysis. Ninety-nine consecutive patients were studied, who were at risk of intra-operative myocardial ischaemia or haemodynamic instability (Class II indications) and were undergoing vascular, visceral or chest surgery. A total of 165 new echocardiographic findings were recorded. Based on these findings changes in drug therapy were made in 47% and changes in fluid therapy in 24% of patients. Left ventricular wall motion abnormalities were seen in 32% and other relevant diagnoses made in 10%. Echocardiography showed a significant impact on drug therapy in patients with pre-operative systolic wall motion abnormalities (vasodilators: OR = 7.1, CI 95% = 2.1/24.0; vasopressors: OR = 3.3, CI 95% = 1.2/9.1) and patients with a history of left heart failure (vasodilators: OR = 5.2, CI 95% = 1.0/31.4). Fluid therapy was significantly influenced by echocardiographic findings during liver and lung transplantation (50% compared with 24% during other surgical interventions, p < 0.05).

Quantitative analysis of left ventricular regional wall motion with color kinesis during abdominal aortic cross-clamping

OBJECTIVES

The authors aimed to establish a technique for quantitative analysis of regional wall motion abnormality (RWMA) using color kinesis (CK) of transesophageal echocardiography (TEE) in surgical patients. This technique was used to determine whether RWMAs develop de novo after infrarenal aortic cross-clamping in patients undergoing vascular surgery with a preoperative dipyridamole thallium stress test (DTST).

DESIGN

An observational study.

SETTING

University hospital.

PARTICIPANTS

Thirty-eight patients undergoing infrarenal abdominal aortic aneurysm resection or aortofemoral bypass.

MEASUREMENTS AND MAIN RESULTS

CK images of the left ventricle (LV) were obtained from the midventricular transgastric short-axis view before and after infrarenal aortic cross-clamping using TEE and analyzed off-line using custom software. The predictive value of the category "reversible perfusion defect" (RD) was also estimated from DTST for predicting new RWMAs with CK. CK analysis is suitable for clinical use based on the comparison with conventional two-dimensional echocardiogram measurements and interobserver variability. CK analysis showed all 7 patients with persistent perfusion defects on DTST had RWMAs. New RWMAs occurred in 2 of 9 patients with RD and in 2 of 15 patients with normal DTST, indicating that there was no significant difference between RD and normal DTST in the incidence of new RWMAs.

CONCLUSIONS

A new method is available for clinical use, which is capable of visualizing RWMAs. These results suggest that new RWMAs introduced by aortic cross-clamping occur irrespective of the risk as assessed by preoperative DTST. CK with the new analysis method might be a useful tool to quantitatively evaluate RWMAs during surgery.

Perioperative myocardial infarction in noncardiac surgery: the diagnostic and prognostic role of cardiac troponins

Despite the number of technologies used, the diagnosis of perioperative myocardial infarction is still a challenge. Studies conducted in surgical series have demonstrated that cardiac troponins (cTns) have both a superior diagnostic sensitivity and specificity, compared with other traditional techniques, and an independent power to predict short- and long-term prognosis. Nevertheless, some points need to be clarified. They include the usefulness of cTns in patients with end-stage renal failure; the standardization of the cTns cut-off for the diagnosis of myocardial injury; the timing of postoperative blood samplings; the cost-effectiveness of a screening in asymptomatic patients; and the possible therapeutic strategies.

Segmental wall motion abnormalities during telerobotic totally endoscopic coronary artery bypass grafting

In addition to single-lung ventilation (SLV), intrathoracic CO2 insufflation is mandatory for adequate exposure during totally endoscopic coronary artery bypass grafting. With transesophageal echocardiography, we investigated biventricular myocardial wall motion in 25 patients with isolated disease of the left anterior descending coronary artery who underwent totally endoscopic coronary artery bypass grafting with the "Da Vinci" robotic surgical system. At distinct time points during the operation, a cine loop of both ventricles was registered from a transgastric mid-short-axis view. Myocardial wall motion analysis was performed according to an established segmentation model of the left ventricle and to an established five-point scale for wall motion (1, normal; 5, dyskinesia). Significant alterations from preoperative baseline wall motion were visible in the septal, inferior, and anterior segments of the left ventricle at some time during the prebypass period, combined with a markedly decreased PaO2 under SLV and increased intrathoracic pressure. The same findings applied to the right ventricle; however, wall motion abnormalities were more pronounced here. After myocardial revascularization, weaning from cardiopulmonary bypass, CO2 deflation, and return to double-lung ventilation, myocardial wall motion recovered to baseline values. Clinically significant hemodynamic instability did not occur. The data suggest that robot-assisted coronary artery bypass grafting leads to significant prebypass alterations of biventricular segmental wall motion. On the basis of our data, it cannot be definitively stated whether the observed results were due to reduced oxygenation during SLV and thus "real" myocardial ischemia, intrathoracic CO2 insufflation with positive pressure leading to mechanical compromise of the heart, absolute or relative hypovolemia, or a combination of these factors. However, in this cohort, which consisted of patients with single-vessel disease and good ventricular function, these changes were of limited clinical relevance.

IMPLICATIONS

Segmental myocardial wall motion was evaluated with transesophageal echocardiography during robot-assisted totally endoscopic coronary artery bypass grafting. Significant biventricular segmental wall motion abnormalities occurred before cardiopulmonary bypass under single-lung ventilation and carbon dioxide insufflation. The changes in myocardial wall motion were of limited clinical relevance.

Randomized study comparing cardiac response in endovascular and open abdominal aortic aneurysm repair

BACKGROUND

The aim was to compare the cardiac response and the incidence of adverse cardiac events during and after endovascular (EVAR) and open (OR) repair of abdominal aortic aneurysms (AAAs).

METHODS

Seventy-six patients with an AAA suitable for EVAR, and in a general condition allowing open surgery were randomized to EVAR (57 patients) or OR (19 patients). The analysis was on an intention-to-treat basis. Haemodynamic variables were assessed intraoperatively before, during and after aortic occlusion. During the procedure myocardial ischaemia was identified with use of electrocardiography (ECG) and transoesophageal echocardiography (TEE). After operation, cardiac complications were diagnosed by clinical observation, 12-lead ECG at 1 h, 1 day and 7 days, echocardiography at 1 month and measurement of cardiac enzymes.

RESULTS

After aortic occlusion, a greater decrease in systemic vascular resistance compared with baseline was observed with OR than with EVAR (- 396 and - 70 dyne s/cm5 respectively; P = 0.03). The stroke work index, as a direct measure of myocardial performance, demonstrated a decrease during OR and an increase during EVAR during aortic occlusion (- 6.6 and + 1.7 g m/m2 respectively; P = 0.03) as well as after aortic occlusion (- 7.6 and + 3.4 g m/m2 respectively; P < 0.01), compared with baseline. The incidence of postoperative clinical cardiac complications was comparable in the two study groups; however, myocardial ischaemia, as observed by ECG and TEE, was observed more frequently in the OR group (ten of 19 versus 15 of 57 patients; P = 0.05).

CONCLUSION

Haemodynamic changes were less severe and there was a lower incidence of myocardial ischaemia during EVAR than during OR. Studies are needed to demonstrate whether this may reduce the operative mortality rate.

Monitoring Perioperative Ischemia

This report addresses monitoring for ischemia during surgery and whether perioperative ischemia leads to increased morbidity and mortality in patients with cor onary artery disease (CAD) who are undergoing sur gery. Based on previous studies, it is generally accepted that perioperative ischemia is common in patients with CAD undergoing noncardiac surgery. The incidence of ischemia during the operative period varies greatly with cardiac risk factors, type of surgery, duration of surgery, and the monitor used to detect ischemia. Be cause perioperative cardiac morbidity is the leading cause of death after anesthesia and surgery, it is pru dent for the anesthesia clinician to have an understand ing of the tools available for monitoring as well as their clinical utility. These tools are summarized, and recom mendations are made regarding their use.

Automated electrocardiograph ST segment trending monitors: accuracy in detecting myocardial ischemia

Continuous automated ST segment trending devices (ST trending monitors) are included in most new operating room electrocardiography (ECG) monitors to facilitate ischemia detection, but their efficacy is not well validated. Therefore, we compared their accuracy with that of Holter ECG recorders in detecting ST segment changes (both analyzed offline) in 94 patients undergoing coronary artery bypass graft surgery. Holter ECG tapes were analyzed using standard criteria for determining ECG ischemic episodes, which were compared with those measured by the ST trending monitors. Overall, 42 ischemic episodes were detected by using the Holter monitor in 30 patients. Of the 42 episodes, 38 (90%) were also detected by the ST trending monitors. Sixteen episodes of ST segment deviation were detected by the ST trending monitors, but not by the Holter. The sensitivity of the three ST trending monitors in detecting ischemia was 75%, 78%, and 60% for the Marquette (Milwaukee, WI), Hewlett Packard (Andover, MA), and Datex (Helsinki, Finland) monitors, respectively, with a specificity of 89%, 71%, and 69% relative to the Holter. Compared with the HP and Datex monitors, the Marquette monitor has the best agreement with the Holter (K 0.64). Conditions in which ST trending monitors may be inaccurate were identified and included the appearance of small R-wave amplitude, drifting baseline, and during periods of conduction abnormalities and pacing. We conclude that ST trending monitors have only moderate sensitivity and specificity (< 75% overall) in accurately detecting ECG ST segment changes compared with Holter ECG recordings. Therefore, sole reliance on ST trending monitors for the detection of myocardial ischemia may be insufficient.

IMPLICATIONS

Using Holter recordings as the reference standard for detection of intraoperative ischemia, ST trending monitors were found to have overall sensitivity and specificity of 74% and 73%, respectively. Several conditions contribute to the inaccuracy of ST trend monitoring, and additional modification of their performance is necessary to achieve better agreement with the Holter analysis.

The surgeon's use of transesophageal echocardiography

Transesophageal echocardiography has become an instrumental diagnostic modality for the accurate evaluation of cardiac and aortic anatomy and function. Multiplanar technology has facilitated improved visualization of structures and enhanced TEE over TTE in many situations. Care of the trauma patient and critically ill patient is improved with the appropriate and timely performance of TEE. Education, certification, credentialing, and determination of competency are areas that need to be addressed continually in the future.

Effects of calcium on left ventricular function early after cardiopulmonary bypass

OBJECTIVES

Evaluation of the effects of intravenous CaCl2 on systolic and diastolic function early after separation from cardiopulmonary bypass (CPB) DESIGN: Prospective study

SETTING

University hospital

PARTICIPANTS

Twenty patients scheduled for elective coronary artery surgery

INTERVENTIONS

Left ventricular (LV) pressures were measured with fluid-filled catheters. Data were digitally recorded during pressure elevation induced by tilt-up of the legs. Transgastric short-axis echocardiographic views of the LV were simultaneously recorded on videotape. Measurements were obtained before the start of CPB, 10 minutes after termination of CPB, after intravenous administration of CaCl2, 5 mg/kg, and 10 minutes later.

MEASUREMENTS AND MAIN RESULTS

Systolic function was evaluated with the slope (Ees, mmHg/mL) of the systolic pressure-volume relation. Diastolic function was evaluated with the chamber stiffness constant (Kc, mmHg/mL) of the diastolic pressure-volume relation. CaCl2 increased Ees from 2.62 +/- 0.46 to 5.58 +/- 0.61 (mean +/- SD), but induced diastolic dysfunction with an increase in Kc from 0.011 +/- 0.006 to 0.019 +/- 0.007. These changes were transient and had disappeared within 10 minutes after administration of CaCl2.

CONCLUSIONS

CaCl2 early after CPB transiently improved systolic function at the expense of an increase in ventricular stiffness, suggesting temporary diastolic dysfunction.

Detection of myocardial ischemia by transesophageal echocardiographically determined changes in left ventricular area in patients undergoing coronary artery bypass surgery

STUDY OBJECTIVE

To evaluate left ventricular (LV) dimensions and function during myocardial ischemic episodes in anesthetized patients undergoing coronary artery bypass surgery.

DESIGN

Prospective, nonrandomized study.

SETTING

Large, medical school-affiliated tertiary-care medical center.

PATIENTS

36 adults undergoing elective primary coronary artery bypass surgery.

INTERVENTIONS

Transesophageal atrial pacing for 3 to 5 minutes at heart rates (HRs) of 65, 70, 80, and 90 beats per minute.

MEASUREMENTS AND MAIN RESULTS

Arterial, pulmonary artery, and venous pressures, transesophageal echocardiographic (TEE) determined LV end-diastolic (EDA) and end-systolic (ESA) areas, and fractional area change (FAC = [FDA-ESA]/EDA). Myocardial ischemia determined as at least 1 mm ST segment deviation at J + 60 milliseconds from 12-lead electrocardiography (ECG) and TEE detected new LV regional wall motion abnormalities. Biplane TEE images were recorded on videotape, and LV EDA and ESA were determined with planimetry from images of the LV short axis. Myocardial ischemia was observed in 12 patients. In these patients, EDA and ESA were higher and FAC lower than those patients without ischemia at the same HR. There were no differences between patients with and without myocardial ischemia with regard to pulmonary artery occlusion pressure, stroke volume, or other hemodynamic variables. The positive predictive values were best for ESA (67%) and EDA (58%), and least for FAC (18%). Negative predictive values were highest for ESA (85%) and EDA (80%), and least for FAC (47%).

CONCLUSIONS

In anesthetized patients undergoing coronary artery bypass surgery, myocardial ischemia observed during atrial pacing results in increases in LV dimensions and decreases in FAC compared with values in patients without ischemia. These results support further investigations of the clinical usefulness of monitoring LV EDA and LV ESA with TEE as a method of myocardial ischemia detection.

Effects of anesthetic technique on myocardial wall motion abnormalities during abdominal aortic surgery

OBJECTIVE

To assess the impact of regional supplemented general anesthesia (RSGEN) on regional myocardial function during abdominal aortic surgery (AAS).

DESIGN

Prospective randomized study.

SETTING

Single academic medical center.

PARTICIPANTS

Seventy-three patients scheduled for infrarenal aortic aneursymectomy.

INTERVENTIONS

Patients received standardized intraoperative anesthetic management consisting of either general anesthesia (GA; n = 37) or general anesthesia supplemented by epidural anesthesia (RSGEN; n = 36).

MEASUREMENTS AND MAIN RESULTS

Hemodynamic measurements and transesophageal echocardiograms (TEE) were obtained at eight intraoperative times. The electrocardiogram (ECG) was continuously recorded using Holter monitoring. Of the 56 patients with interpretable TEE recordings, 8 of 30 (27%) GA patients and 7 of 26 (27%) RSGEN patients developed new segmental wall motion abnormalities (SWMAs). There was no treatment effect on either the incidence (p = 0.23) or the intensity (p = 0.34) of SWMAs. Cross-clamping of the aorta was associated with the onset of new SWMAs (odds ratio, 8.2; 95% CI, 1.1 to 64; p = 0.04). Among the 63 patients with interpretable Holter recordings, 9 of 34 (26%) GA patients and 9 of 29 (31%) RSGEN patients exhibited intraoperative ischemia. There was no treatment effect on the incidence (p = 0.22) or intensity (p = 0.67) of ECG ischemia.

CONCLUSION

Despite providing modest hemodynamic depression, RSGEN did not reduce the incidence or intensity of either regional myocardial dysfunction or ECG ischemia. New SWMAs were temporally associated with cross-clamping of the aorta and tended to resolve with unclamping.

Evaluation of the effects of mivacurium chloride on hemodynamics and left ventricular function in patients with coronary artery disease undergoing abdominal aortic surgery

OBJECTIVE

To determine the effects of two doses of mivacurium chloride on hemodynamics and left ventricular function in patients with documented coronary artery disease undergoing aortic surgery.

DESIGN

A prospective study with the dose of mivacurium determined by randomization.

SETTING

Induction area at a university hospital.

PARTICIPANTS

Twenty consecutive patients undergoing aortic surgery with clinically and/or angiographically documented coronary artery disease.

INTERVENTIONS

Intravenous administration of mivacurium chloride.

MEASUREMENTS AND MAIN RESULTS

Induction of anesthesia was performed with midazolam and fentanyl. Two different doses of mivacurium chloride, 0.15 mg/kg (n = 10) and 0.2 mg/kg (n = 10; 2 and 2.5 ED95; respectively), were administered as a single bolus injection over a 60-second period in the absence of any surgical stimulation. In addition to standard hemodynamic monitoring, pulmonary artery catheterization and transesophageal echocardiography were used. The occurrence of myocardial ischemia was monitored using both a computerized three-lead ST-segment analysis system and the echocardiographic assessment of regional wall motion. No change in heart rate, mean arterial pressure, pulmonary capillary wedge pressure, cardiac output, and global left ventricular function was noted after administration of mivacurium with the two doses studied. No ST-segment change or new segmental wall motion abnormality was noted in either group.

CONCLUSION

Mivacurium chloride, when injected over a 60-second period, preserves global and regional myocardial function in patients with documented coronary artery disease undergoing noncardiac surgery.

Effects of lidoflazine on left ventricular function in patients

OBJECTIVE

The present study evaluated the effects of the nucleoside transport inhibitor, lidoflazine, at a dose of 1 mg/kg, on left ventricular function.

DESIGN

Patients were randomly assigned to receive either lidoflazine or saline in a double-blind manner.

SETTING

A university hospital.

PARTICIPANTS

The study was performed in 32 patients scheduled for elective coronary artery bypass surgery.

INTERVENTIONS

Left ventricular pressures were measured with fluid-filled catheters. Data were digitally recorded during pressure elevation induced by tilt-up of the legs. Transgastric short-axis echocardiographic views of the left ventricle were simultaneously recorded on videotape. Systolic function was evaluated with the slope (Ees, mmHg/mL) of the systolic pressure-volume relationship. Diastolic function was evaluated with the chamber stiffness constant (Kc, mmHg/mL) of the diastolic pressure-volume relationship. Cardiac function was assessed at baseline and after administration of either lidoflazine (group A [n = 16]) or placebo (group B [n = 16]). Data were compared using two-factor analysis of variance.

MEASUREMENTS AND MAIN RESULTS

At baseline, diastolic and systolic function were comparable in both groups. Lidoflazine increased Kc from 0.079 +/- 0.015 to 0.125 +/- 0.017 mmHg/mL and decreased Ees from 2.481 +/- 0.213 to 1.217 +/- 0.211 mmHg/mL (p = 0.009 and p = 0.004, respectively). None of these changes occurred when placebo was administered.

CONCLUSIONS

Administration of lidoflazine before the start of cardiopulmonary bypass impaired left ventricular systolic function but also increased diastolic stiffness.