Major Vascular Surgery Patients Research Articles

Ambulatory Cardiology or General Internal Medicine Assessment Prior to Scheduled Major Vascular Surgery is Associated with Improved Outcomes.

To characterize the association between ambulatory cardiology or general internal medicine (GIM) assessment prior to surgery and outcomes following scheduled major vascular surgery. Cardiovascular risk assessment and management prior to high-risk surgery remains an evolving area of care. This is population-based retrospective cohort study of all adults who underwent scheduled major vascular surgery in Ontario, Canada, April 1, 2004-March 31, 2019. Patients who had an ambulatory cardiology and/or GIM assessment within 6 months prior to surgery were compared to those who did not. The primary outcome was 30-day mortality. Secondary outcomes included: composite of 30-day mortality, myocardial infarction or stroke; 30-day cardiovascular death; 1-year mortality; composite of 1-year mortality, myocardial infarction or stroke; and 1-year cardiovascular death. Cox proportional hazard regression using inverse probability of treatment weighting (IPTW) was used to mitigate confounding by indication. Among 50,228 patients, 20,484 (40.8%) underwent an ambulatory assessment prior to surgery: 11,074 (54.1%) with cardiology, 8,071 (39.4%) with GIM and 1,339 (6.5%) with both. Compared to patients who did not, those who underwent an assessment had a higher Revised Cardiac Risk Index (N with Index over 2= 4,989[24.4%] vs. 4,587[15.4%], P<0.001) and more frequent pre-operative cardiac testing (N=7,772[37.9%] vs. 6,113[20.6%], P<0.001) but, lower 30-day mortality (N=551[2.7%] vs. 970[3.3%], P<0.001). After application of IPTW, cardiology or GIM assessment prior to surgery remained associated with a lower 30-day mortality (weighted Hazard Ratio [95%CI] = 0.73 [0.65-0.82]) and a lower rate of all secondary outcomes. Major vascular surgery patients assessed by a cardiology or GIM physician prior to surgery have better outcomes than those who are not. Further research is needed to better understand potential mechanisms of benefit.

Relationship between risk stratification scores and sublingual microcirculatory monitoring in major vascular surgery patients: preliminary results

Relationship between risk stratification scores and sublingual microcirculatory monitoring in major vascular surgery patients: preliminary results

Abstract 12636: Association Between Pre-Operative Specialist Assessment and Adverse Outcomes Among Patients Scheduled for Major Vascular Surgery

Background: The impact of pre-operative specialist assessment on outcomes following high-risk vascular surgery remains uncertain. Our objective was to characterize the association between pre-operative cardiology or general internal medicine (GIM) assessment and post-operative outcomes following scheduled major vascular surgery. Methods: This is a population-based cohort study of all adult scheduled major vascular surgery patients in Ontario, Canada (April 1, 2004-March 31, 2019). Those who underwent an ambulatory cardiology and/or GIM assessment within 6 months prior to surgery were compared to those who did not. The primary outcome was 30-day mortality. Secondary outcomes included 30-day mortality, myocardial infarction or stroke; 30-day cardiovascular death; 1-year mortality; 1-year mortality, myocardial infarction or stroke; and 1-year cardiovascular death. Multivariable cox proportional hazard regression using inverse probability of treatment weighting (IPTW) was used to mitigate confounding by indication. Results: Among 50,228 scheduled major vascular surgery patients, 20,484 underwent pre-operative ambulatory specialist assessment: 11,074 (54.1%) with cardiology, 8,071 (39.4%) with GIM and 1,339 (6.5%) with both. Patients who underwent cardiology or GIM assessment had a higher Revised Cardiac Risk Index (N with Index over 2= 4,989 [24.4%] vs. 4,587 [15.4%], p&lt;0.001) and more frequent pre-operative cardiac testing (N=7,772 [37.9%] vs. 6,113 [20.6%], p&lt;0.001) but had lower crude 30-day mortality (N=551 [2.7%] vs. 970 [3.3%], p&lt;0.001). After application of IPTW, pre-operative specialist assessment remained associated with a lower rate of 30-day mortality (Hazard Ratio [95%CI] = 0.73 [0.65-0.82]) and a lower rate of all secondary outcomes (Figure). Conclusion: Pre-operative ambulatory cardiology or GIM assessment is associated with improved outcomes following scheduled major vascular surgery

Potential New Approaches in Predicting Adverse Cardiac Events One Month after Major Vascular Surgery

Objective: The aim of our study was to find the best model with sufficient power to improve the risk stratification in major vascular surgery patients during the first 30 days after this procedure. The discriminatory power of 4 biomarkers (troponin I [TnI], N-terminal prohormone of brain natriuretic peptide [NT-proBNP], creatine kinase-MB isoenzyme [CK-MB], high-sensitivity C-reactive protein [hs-CRP]) was tested as well as 2 risk assessment models and 13 different combinations of them. Subjects and Methods: The study included 122 patients (77% men, 23% women) with an average age of 67.03 ± 4.5 years. An aortobifemoral bypass was performed in 6.56% of the patients, a femoropopliteal bypass in 18.85%, and 49.18% received open surgical reconstruction of the carotid arteries. A total of 25.41% of the patients were given an aortobi-iliac bypass. Results: During the first 30 days, 13 patients (10.7%) had 17 cardiac complications. The most common complication was the new onset of atrial fibrillation (35.3%). During the first 10 days, 10 patients had 1 complication and 2 patients had 2 cardiac events, while 1 patient had 3 complications. By comparing combinations of scores and markers, it was shown that revised cardiac risk index (RCRI) + Vascular Portsmouth Physiological and Operative Severity Score (V-POSSUM) + hsTnI and RCRI + V-POSSUM + hsTnI + NT-proBNP with 100% sensitivity, > 80% specificity had the best discriminatory ability (AUC 0.924 and 0.933, respectively; p < 0.001 for both models) for cardiac complications during the 30 days after surgery. Conclusion: Combinations of traditional preoperative risk factors and scores can enhance the assessment of major adverse cardiac events (MACE) in patients preparing for large vascular surgery. Using only one risk score in these patients seems to be underperforming in preoperative risk assessment.

The long-term impact of early cardiovascular therapy intensification for postoperative troponin elevation after major vascular surgery.

Acute cardiac events are a frequent cause of morbidity after vascular surgery. The impact of early evidence-based treatment for patients with an acute cardiac event after vascular surgery on long-term postoperative outcomes has not been extensively studied. We hypothesized that providing appropriate evidence-based treatment to patients with elevated postoperative cardiac troponin levels may limit long-term mortality. We conducted a study of 667 consecutive major vascular surgery patients with an elevated postoperative troponin I level. We then determined which of these patients received medical therapy as per the 2007 American College of Cardiology/American Heart Association recommendations for the medical management of patients with chronic stable angina. All patients with troponin elevation were then matched with 2 control patients without postoperative troponin elevation. Matching was done using logistic regression and nearest-neighbor matching methods. The primary study end point was 12 months survival without a major cardiac event (i.e., death, myocardial infarction, coronary revascularization, or pulmonary edema requiring hospitalization). Therapy was intensified in 43 of 66 patients (65%) who suffered a troponin I elevation after surgery. Patients with a troponin I elevation not receiving intensified cardiovascular treatment had a hazard ratio (HR) of 1.77 (95% confidence interval (CI), 1.13-2.42; P = 0.004) for the primary study outcome as compared with the control group. In contrast, patients with a troponin I elevation who received intensified cardiovascular treatment had an HR of 0.63 (95% CI, 0.10-1.19; P = 0.45) for the primary outcome as compared with the control group. Patients with a troponin I elevation not receiving treatment intensification likely were at higher risk for a major cardiac event (HR, 2.80; 95% CI, 1.05-24.2; P = 0.04) compared with patients who did receive treatment intensification. The main finding of this study was that in patients with elevated troponin I levels after noncardiac surgery, long-term adverse cardiac outcomes may likely be improved by following evidence-based recommendations for the medical management of acute coronary syndromes.

An Article on the Predictive Value of on Treatment Platelet Reactivity in Major Vascular Surgery Patients

Background: Ageing is associated with a marked reduction in capacity for angiogenesis and vascular regeneration. In elderly males, ageing is also associated with a decline in androgen levels. We examined the effects of ageing on androgenmodulation of angiogenesis in young and old human fibroblasts. Methods:Human dermal fibroblasts were isolated from young (30 yrs) and older males (>65 yrs). Cells were incubated with 40nM dihydrotestosterone (DHT), with or without hydroxyflutamide (HF), or a phosphoinositide 3-kinase (PI3-kinase) inhibitor. Fibroblasts and fibroblastconditioned media was used to stimulate HUVECs, and analysed by ELISA and western blotting. Nuclear fractionation and fluorescencemicroscopywere used to study androgen receptor (AR) localisation. Results: Young male fibroblasts treated with DHT doubled HUVEC tubulogenesis and migration through increased VEGF secretion (p< 0.05). Older male fibroblasts were unresponsive to DHT treatment with a lack of VEGF production and could not stimulate enhanced angiogenesis in HUVECs. DHT-induced stimulation of VEGF secretion from young fibroblasts was dependent on AR binding and increased nuclear AR translocation (p< 0.01). Thiswas associatedwith increasedAKTproduction (p< 0.05) and phosphorylation (p< 0.01), all of which was abrogated by PI3-kinase inhibition. Despite comparable level of ARs, fibroblasts from older males treated with DHT displayed reduced AR nuclear translocation, resulting in a lack of AR-mediated VEGF production. Conclusion: Unlike young male fibroblasts, older male cells cannot respond to DHT treatment with increased VEGF production and angiogenic promotion of endothelial cellsdue todefectivenuclear translocationof androgen receptors.

A Cohort Study of Nutrition Practices in the Intensive Care Unit Following Abdominal Aortic Aneurysm Repair

Enteral nutrition within 48 hours of intensive care unit (ICU) admission is recommended for the ICU population. Major vascular surgery patients have a higher incidence of pre- and postoperative malnutrition compared with the general surgical population. Our objectives were to determine if early feeding (within 48 hours of admission) is achievable and well tolerated, identify factors that predict early feeding, and determine if there is an association between early feeding and in-hospital mortality among abdominal aortic aneurysm (AAA) repair patients. A retrospective cohort study was conducted among 145 postsurgical AAA repair patients admitted to the ICU within 48 hours of surgery. Kaplan-Meier methods and Cox proportional hazard multiple regression were used to analyze the data. Only 35 (24%) patients received early feeding. Patients were more likely to be fed early if they were male (adjusted hazard ratio [aHR] = 2.3; 95% confidence interval [CI], 0.8-6.7; P = .13), had endovascular AAA repair (aHR = 2.9; 95% CI, 1.4-6.2; P = .006), had less blood loss (<4 L) during surgery (aHR = 2.3; 95% CI, 0.7-7.2; P = .14), and had shorter length of ventilation (<48 hours) (aHR = 2.2; 95% CI, 1.1-4.8; P = .048). Of 44 patients fed via enteral nutrition (EN), 27 (61%) achieved nutrition adequacy (>80% EN goal) during ICU admission. After controlling for other factors, 14-day mortality was not related to feeding time (aHR = 1.1; P = .88). Early feeding was achieved in a minority of patients following AAA repair, was related to type of surgery and duration of mechanical ventilation, and was tolerated as well as later introduced feedings. Randomized trials are needed to determine safety and benefits of early feeding in this patient group.

Value of Specialized Preanesthetic Clinic for Cardiac and Major Vascular Surgery Patients

In a complicated and specialized population, such as patients undergoing cardiac and major vascular procedures, patients, clinicians, and hospitals may be best served and resources conserved with a specialized preanesthesia clinic. A specialized preanesthesia clinic for cardiac and major vascular procedures has a focused staff usually consisting of practitioners with cardiac and major vascular surgical care experience designed to address the patient evaluation, the information gathering, the necessary consultations, the required testing, and specific needs for the day of cardiac and major vascular surgery. Specialized preanesthesia clinics increase patient satisfaction and may also provide cost containment by decreasing the amount of indiscriminate ordering of expensive preoperative tests and potentially may decrease patient litigation. Resident trainee education can also be enhanced by a specialized preanesthesia clinic for cardiac and major vascular rotations. The ultimate goal of a specialized preanesthesia clinic is to ensure a safe and efficient perioperative cardiac and major vascular surgical experience in complicated patients undergoing complex procedures.

The efficacy and safety of clopidogrel in vascular surgery patients with immediate postoperative asymptomatic troponin T release for the prevention of late cardiac events: Rationale and design of the Dutch Echocardiographic Cardiac Risk Evaluation Applying Stress Echo-VII (DECREASE-VII) trial

Major vascular surgery patients are at high risk for developing asymptomatic perioperative myocardial ischemia reflected by a postoperative troponin release without the presence of chest pain or electrocardiographic abnormalities. Long-term prognosis is severely compromised and characterized by an increased risk of long-term mortality and cardiovascular events. Current guidelines on perioperative care recommend single antiplatelet therapy with aspirin as prophylaxis for cardiovascular events. However, as perioperative surgical stress results in a prolonged hypercoagulable state, the postoperative addition of clopidogrel to aspirin within 7 days after perioperative asymptomatic cardiac ischemia could provide improved effective prevention for cardiovascular events. DECREASE-VII is a phase III, randomized, double-blind, placebo-controlled, multicenter clinical trial designed to evaluate the efficacy and safety of early postoperative dual antiplatelet therapy (aspirin and clopidogrel) for the prevention of cardiovascular events after major vascular surgery. Eligible patients undergoing a major vascular surgery (abdominal aorta or lower extremity vascular surgery) who developed perioperative asymptomatic troponin release are randomized 1:1 to clopidogrel or placebo (300-mg loading dose, followed by 75 mg daily) in addition to standard medical treatment with aspirin. The primary efficacy end point is the composite of cardiovascular death, stroke, or severe ischemia of the coronary or peripheral arterial circulation leading to an intervention. The evaluation of long-term safety includes bleeding defined by TIMI criteria. Recruitment began early 2010. The trial will continue until 750 patients are included and followed for at least 12 months. DECREASE-VII is evaluating whether early postoperative dual antiplatelet therapy for patients developing asymptomatic cardiac ischemia after vascular surgery reduces cardiovascular events with a favorable safety profile.

Relation between Preoperative and Intraoperative New Wall Motion Abnormalities in Vascular Surgery Patients

Coronary revascularization of the suspected culprit coronary lesion assessed by preoperative stress testing is not associated with improved outcome in vascular surgery patients. Fifty-four major vascular surgery patients underwent preoperative dobutamine echocardiography and intraoperative transesophageal echocardiography. The locations of left ventricular rest wall motion abnormalities and new wall motion abnormalities (NWMAs) were scored using a seven-wall model. During 30-day follow-up, postoperative cardiac troponin release, myocardial infarction, and cardiac death were noted. Rest wall motion abnormalities were noted by dobutamine echocardiography in 17 patients (31%), and transesophageal echocardiography was noted in 16 (30%). NWMAs were induced during dobutamine echocardiography in 17 patients (31%), whereas NWMAs were observed by transesophageal echocardiography in 23 (43%), kappa value = 0.65. Although preoperative and intraoperative rest wall motion abnormalities showed an excellent agreement for the location (kappa value = 0.92), the agreement for preoperative and intraoperative NWMAs in different locations was poor (kappa value = 0.26-0.44). The composite cardiac endpoint occurred in 14 patients (26%). There was a poor correlation between the locations of preoperatively assessed stress-induced NWMAs by dobutamine echocardiography and those observed intraoperatively using transesophageal echocardiography. However, the composite endpoint of outcome was met more frequently in relation with intraoperative NWMAs.

The Need for Specialized Preanesthesia Clinics for Day Admission Cardiac and Major Vascular Surgery Patients

The majority of patients undergoing surgical procedures today are not admitted to the hospital prior to the morning of surgery. In a medical world that strives not only for patient safety, but also for cost containment, Day Admission Surgery (DAS) plays an important role in our healthcare systems. This is true even for patients undergoing cardiac and major vascular (CMV) procedures. However, CMV patients often present with more complicated pre-, intra- and post-operative issues than other surgical patients.In order to optimize the preoperative evaluation and care of CMV patients, we developed a specialized Pre-Anesthesia Clinic (PAC). We believed that patients, surgeons, anesthesiologists, and intensive care unit (ICU) teams would all benefit when appropriate preoperative evaluations are thoughtfully performed by those specializing in the care of these complicated patients. Planning for this specialized clinic included a survey of other institutions' practices. Following initiation of our clinic, we performed a patient satisfaction survey. We report these findings along with the demographic data concerning the patients and types of surgeries evaluated in our initial experience. Finally, we discuss the preoperative evaluation including various areas of assessment provided by our PAC.

Perioperative Blood Glucose Monitoring and Control in Major Vascular Surgery Patients

Diabetes mellitus (DM) is an independent predictor for morbidity and mortality in the general population, which is even more apparent in patients with concomitant cardiovascular risk factors. As the prevalence of DM is increasing, with an ageing general population, it is expected that the number of diabetic patients requiring surgical interventions will increase. Perioperative hyperglycaemia, without known DM, has been identified as a predictor for morbidity and mortality in patients undergoing surgery. Moreover, early studies showed that intensive blood-glucose-lowering therapy reduced both morbidity and mortality among patients admitted to the postoperative intensive care unit (ICU). However, later studies have doubted the benefit of intensive glucose control in medical–surgical ICU patients. This article aims to comprehensively review the evidence on the use of perioperative intensive glucose control, and to provide recommendations for current clinical practice. A systematic review was performed of the literature on perioperative intensive glucose control. Based on this literature review, we observed that intensive glucose control in the perioperative period has no clear benefit on short-term mortality. Intensive glucose control may even have a net harmful effect in selected patients. In addition, concerns on the external validity of some studies are important barriers for widespread recommendation of intensive glucose control in the perioperative setting. We propose that guidelines recommending intensive glucose control should be re-evaluated. In addition, moderate tight glucose control should currently be regarded as the safest and most efficient approach to patients undergoing major vascular surgery.

Perioperative Blood Glucose Monitoring and Control in Major Vascular Surgery Patients

Diabetes mellitus (DM) is an independent predictor for morbidity and mortality in the general population, which is even more apparent in patients with concomitant cardiovascular risk factors. As the prevalence of DM is increasing, with an ageing general population, it is expected that the number of diabetic patients requiring surgical interventions will increase. Perioperative hyperglycaemia, without known DM, has been identified as a predictor for morbidity and mortality in patients undergoing surgery. Moreover, early studies showed that intensive blood-glucose-lowering therapy reduced both morbidity and mortality among patients admitted to the postoperative intensive care unit (ICU). However, later studies have doubted the benefit of intensive glucose control in medical-surgical ICU patients. This article aims to comprehensively review the evidence on the use of perioperative intensive glucose control, and to provide recommendations for current clinical practice. A systematic review was performed of the literature on perioperative intensive glucose control. Based on this literature review, we observed that intensive glucose control in the perioperative period has no clear benefit on short-term mortality. Intensive glucose control may even have a net harmful effect in selected patients. In addition, concerns on the external validity of some studies are important barriers for widespread recommendation of intensive glucose control in the perioperative setting. We propose that guidelines recommending intensive glucose control should be re-evaluated. In addition, moderate tight glucose control should currently be regarded as the safest and most efficient approach to patients undergoing major vascular surgery.

Intraoperative Fluid Restriction Predicts Improved Outcomes in Major Vascular Surgery

Traditional fluid resuscitation during general anesthesia has been questioned in recent studies. One study of patients undergoing abdominal surgery showed decreased postoperative weight gain, earlier return of bowel function, and shorter intensive care unit (ICU) and hospital length of stay (LOS) when intraoperative crystalloid infusion was restricted. The authors conducted a retrospective study of major vascular surgery patients (neo-aorto iliac system surgery) to correlate clinical outcomes with intraoperative crystalloid fluid administration. The charts of 41 patients who underwent major vascular surgery at our institution were reviewed. Patients were grouped according to the crystalloid volume infused intraoperatively into <3 L (group 1) and >3 L (group 2). Preoperative and postoperative weights, intraoperative crystalloid administration, intraoperative vasopressor use, preoperative and postoperative creatinine, number of days to clear liquid diet, and the time to discharge from the ICU (ICU LOS) and hospital (hospital LOS) were collected. There were statistically significant differences in duration of mechanical ventilation (0.55 +/- 0.934 vs 2.03 +/- 2.735 days, P = .013) and ICU LOS (3.0 +/- 1.48 vs 5.79 +/- 3.938, P = .029) in favor of the fluid restriction group. Major postoperative complications, such as sepsis, acute myocardial infarction, and graft thrombosis, were less frequent in the fluid restriction group but not statistically significant (5 vs 9, P = .742). Intraoperative crystalloid volume was found to be an independent predictor of ICU LOS after adjusting for estimated blood loss and duration of surgery. There was no statistically significant difference in preoperative serum albumin in both groups. Restricted intraoperative administration of crystalloid fluids (<3 L) may be beneficial in major vascular surgery patients. These benefits are similar to those previously described in patients undergoing abdominal surgery.

A clinical survival score predicts the likelihood to benefit from preoperative thallium scanning and coronary revascularization before major vascular surgery

Guidelines advocate selective non-invasive testing before major non-cardiac surgery, yet data defining who may benefit from such tests is lacking. We aimed to find the predictors that define patients who are most likely to benefit from preoperative cardiac testing and coronary revascularization (CR). In 624 consecutive major vascular surgery patients, the preoperative thallium scanning (PTS) results and subsequent CRs were correlated with long-term (3-15 years) survival. Of all patients, 510 (80.6%) had PTS, 154 (24.7%) had moderate-severe ischaemia on PTS, and 96 (15.4%) underwent CR. Seven predictors: age >or=65, diabetes, cerebrovascular disease, ischaemic heart disease, congestive heart failure, ST-depression on preoperative ECG, and renal insufficiency, independently determined long-term survival. A long-term survival score (LTSS) comprised of these predictors, divided all patients into low, intermediate, and high-risk groups (0-1, 2-3, >or=4 predictors, respectively) with a 5-year survival of 83 +/- 2%, 60 +/- 3%, and 34 +/- 6%, respectively. Compared with low-risk patients, intermediate and high-risk patients had worse survival [HR (CI) = 2.6 (2.0-3.4) and 5.9 (4.1-8.9), respectively, P < 0.001]. Yet, only the intermediate-risk group had better long-term survival following preoperative CR [HR = 0.48 (0.31-0.75), P = 0.001]. The low-risk groups' favourable survival and high-risk groups' poor survival were not significantly affected by CR. Intermediate-risk patients (LTSS 2-3) are most likely to have a long-term survival benefit from PTS and CR.

The safety and effectiveness of esmolol in the perioperative period in patients undergoing abdominal aortic surgery

Objectives: To determine (1) if perioperative use of esmolol in major vascular surgery patients provides strict heart rate (HR) control, (2) what doses of esmolol are required to do this, and (3) does this control influence myocardial ischemia or result in adverse consequences. Design: Prospective study of 40 patients randomized to two groups: The HR was controlled to either less than 80 beats/min (group 80) or less than 110 beats/min (group 110) using esmolol. Patients were monitored continuously for electrocardiographic changes perioperatively. HR control began after induction of anesthesia and continued for 48 hours thereafter. Setting: Operating room and intensive care unit. Patients: Patients undergoing abdominal vascular surgery involving aortic cross-clamping. Interventions: Esmolol was titrated until the target HR was met. Measurements and Results: Only one patient demonstrated an adverse effect. The median infusion rates were 100 and 12.5 μg/kg/min for groups 80 and 110. Target HR was met less in group 80 than in group 110, primarily in the postoperative period. Ischemia patterns were not significantly different between groups. Conclusion: Using esmolol for HR control in the intraoperative period for abdominal vascular surgery patients is effective and safe. HR control was much less effective in the postoperative period, but esmolol is safe when used at recommended doses. Further study with a larger number of patients is necessary to determine whether strict HR control with esmolol affects the incidence of myocardial ischemia or infarction in this patient population.

ASSOCIATION BETWEEN PROLONGED ISCHEMIA ON CONTINUOUS 12-LEAD ECG AND MYOCARDIAL INJURY, DETECTED BY AN INCREASE IN TROPONIN-I, FOLLOWING MAJOR VASCULAR SURGERY

Introduction. Previous studies implied that cardiac complication after major non-cardiac surgery are preceded by long-duration Holter detected ischemia [1,2]. The present study intends to corroborate those findings using continuous, on-line 12-lead ST-trend monitoring and Troponin-I measurements. Methods. With the approval of our IRB, 132 consecutive major vascular surgery patients (54 carotid, 17 abdominal aortic and 61 infra-inguinal bypass procedures) were studies. All patients were monitored by continuous 12-lead ECG with on-line ST-trend analysis (Marquette Solar 7000 and ST-Guard station) starting before induction of anesthesia till 48-72 hrs thereafter. Patients were followed for cardiac signs and symptoms and serum cardiac Troponin-I (cT-I) was measured daily for the first 3 postoperative days. Ischemia was defined as ST depression > 1 mm in >or=to 2 leads, or > 2 mm in 1 lead, or ST elevation > 2mm, lasting > 10 min. Myocardial injury was defined as an increase in cT-I > 2.5 times above its upper limit of normal (i.e., > 3.75 = 2.5 x 1.5 ng/ml). Results. 32 patients had ischemic episodes, longest of which lasting 90 +/- 94 min [range 11-452]. In all but 1 patient these were pure ST segment depressions. 7 patients had myocardial injury, 4 of them asymptomatic. Figure 1 describes the correlation between longest ischemia duration and highest cT-I (Pearson's correlation coefficient r=0.66, p<0.001). All but 1 patient with ischemia > 120 min had myocardial injury and all but 1 patients with elevated myocardial injury had ischemia > 120 min. In all but 1 patient ischemic ECG changes reverted completely to baseline after the end of ischemia. One patient with prolonged ischemia and myocardial injury died from cardiac arrest 1 week after surgery.Figure 1Conclusions: Prolonged (> 120 min) ischemia, denoted by ST depression precedes most postop myocardial injuries detected by cT-I.. Thus, in accordance with previous reports, perioperative myocardial ischemia may be the leading cause of postoperative myocardial infarction.

The patient with coronary artery disease scheduled for noncardiac surgery

Summary Cardiovascular morbidity continues to represent the single most important contributor to surgical mortality. The impact of postoperative interventions in potentially improving cardiovascular morbidity and mortality is extremely difficult to separate from the influence of the intra-operative technique. It is most likely that the combination of techniques used intra-operatively and postoperatively have a combined impact on cardiovascular outcome. A thorough preoperative assessment of the patient to determine the probability of risk for coronary artery disease and whether further workup will improve patient outcome is essential. Perioperative interventions such as coronary artery bypass grafting have not always shown a subsequent reduction in patient morbidity before noncardiac surgery. Other perioperative interventions such as percutaneous transluminal coronary angioplasty and the insertion of an intraaortic balloon pump may provide more patient benefit with less risk than coronary artery bypass graft. Intra-operative monitoring devices are only helpful if clinicians can interpret and extrapolate meaningful data that will assist them in achieving an end-point (detection and prevention of myocardial ischemia) for their patient's management. A familiarity of the sensitivity and specificity of a particular monitoring device is helpful to determine the best method for detecting myocardial ischemia. A smooth transition from the intraoperative to the postoperative period is desirable. Attenuation of the neurohumeral stress response through adequate pain management may reduce the incidence of postoperative morbid cardiac events. Regional techniques may hold the greatest promise for effecting significant improvements in cardiovascular outcome. Yeager's study is conclusive in showing that epidural anesthesia and analgesia results in decreased morbidity and mortality for major vascular surgery patients. Tuman 55 showed decreased hypercoagulability with epidural anesthesia that may be a critical physiological benefit in reducing the incidence of vascular graft occlusion, coronary artery occlusion, and deep venous thromboses. Blomberg's studies in patients with severe coronary artery disease provide insight into the mechanisms by which epidural anesthesia may be a therapeutic measure in preventing and treating myocardial ischemia. Perhaps we should consider using thoracic epidural anesthesia for patients with coronary artery disease scheduled for noncardiac surgery to reduce the incidence or even the occurrence of perioperative myocardial infarction. Perhaps thoracic epidural anesthesia will replace our conventional therapies for myocardial ischemia. Only further investigation of this hypothesis will elucidate the answer.