Development of a bariatric surgery specific risk assessment tool for perioperative myocardial infarction

BackgroundPerioperative myocardial infarction (PMI) is a feared complication after surgery. Bariatric surgery, due to its intraabdominal nature, is traditionally considered an intermediate risk procedure. However, there are limited data on MI rates and its predictors in patients undergoing bariatric surgery.ObjectivesTo enumerate the prevalence of PMI after bariatric surgery and develop a risk assessment tool.SettingBariatric surgery centers, United States.MethodsPatients undergoing bariatric surgery were identified from the MBSAQIP participant use file (PUF) 2016. Preoperative characteristics, which correlated with PMI were identified by multivariable regression analysis. PUF 2015 was used to validate the scoring tool developed from PUF 2016.ResultsWe identified 172,017 patients from PUF 2016. Event rate for MI within 30 days of the operation was .03%; with a mortality rate of 17.3% in patients with a PMI. Four variables correlated with PMI on regression, including history of a previous MI (odds ratio [OR] = 8.57, confidence interval [CI] = 3.4–21.0), preoperative renal insufficiency (OR = 3.83, CI = 1.2–11.4), hyperlipidemia (OR = 2.60, CI = 1.3–5.1), and age >50 (OR = 2.15, CI = 1.1–4.2). Each predicting variable was assigned a score and event rate for MI was assessed with increasing risk score in PUF 2015; the rate increased from 9.5 per 100,000 operations with a score of 0 to 3.2 per 100 with a score of 5.ConclusionThe prevalence of MI after bariatric surgery is lower than other intraabdominal surgeries. However, mortality with PMI is high. This scoring tool can be used by bariatric surgeons to identify patients who will benefit from focused perioperative cardiac workup.     

The incidence of perioperative myocardial infarction in general vascular surgery.

In a 1-year period all patients undergoing general vascular surgery (491 patients, 534 procedures) underwent monitoring by creatine phosphokinase isoenzymes and electrocardiograms (ECG) to detect perioperative myocardial infarction. Only those patients with severe symptomatic coronary artery disease (31 patients, 5.8%) characterized by unstable angina pectoris, uncontrolled arrhythmia, or severe congestive heart failure had any testing for coronary artery disease beyond history, physical examination, and ECG. Only three patients (0.5%) had prophylactic coronary artery bypass performed before general vascular procedures. Twenty-one (3.9%) myocardial infarctions (five asymptomatic, detected by enzymes only, and 16 symptomatic, four of which were fatal) were associated with the 534 procedures (aorta 105, carotid 87, infrainguinal bypass 207, extraanatomic 51, other 84). Eight noncardiac perioperative deaths occurred. All operative deaths (12 of 534, 2.2%) including all four fatal myocardial infarctions occurred associated with surgery on an urgent or emergency basis (12 of 249 procedures, urgent/emergent operative mortality rate 4.8%). No operative deaths and no fatal myocardial infarctions associated with the 285 elective procedures occurred. Nine of the 17 nonfatal myocardial infarctions (53%) also occurred after urgent/emergent procedures. The rate of perioperative myocardial infarctions (eight of 285, 2.8%) after elective surgery in this patient series is no different from that reported by multiple recent authors advocating widespread screening for and prophylactic treatment of coronary artery disease before general vascular surgery. Our experience confirms the therapeutic approach that expensive and invasive coronary screening programs in patients to undergo vascular operations should be limited to carefully selected patients with severely symptomatic coronary disease.     

Analysis of risk factors for myocardial infarction and cardiac mortality after major vascular surgery

BACKGROUND: Patients undergoing vascular surgical procedures are at high risk for perioperative myocardial infarction (PMI). This study was undertaken to identify predictors of PMI and in-hospital death in major vascular surgical patients. METHODS: From the Vascular Surgery Registry (6,948 operations from January 1989 through June 1997) the authors identified 107 patients in whom PMI developed during the same hospital stay. Case-control patients (patients without PMI) were matched at a 1x:x1 ratio with index cases according to the type of surgery, gender, patient age, and year of surgery. The authors analyzed data regarding preoperative cardiac disease and surgical and anesthetic factors to study association with PMI and cardiac death. RESULTS: By using univariable analysis the authors identified the following predictors of PMI: valvular disease (P = 0.007), previous congestive heart failure (P = 0.04), emergency surgery (P = 0.02), general anesthesia (P = 0.03), preoperative history of coronary artery disease (P = 0.001), preoperative treatment with beta-blockers (P = 0.003), lower preoperative (P = 0.03) and postoperative (P = 0.002) hemoglobin concentrations, increased bleeding rate (as assessed from increased cell salvage; P = 0.025), and lower ejection fraction (P = 0.02). Of the 107 patients with PMI, 20.6% died of cardiac cause during the same hospital stay. The following factors increased the odds ratios for cardiac death: age (P = 0.001), recent congestive heart failure (P = 0.01), type of surgery (P = 0.04), emergency surgery (P = 0.02), lower intraoperative diastolic blood pressure (P = 0.001), new intraoperative ST-T changes (P = 0.01), and increased intraoperative use of blood (P = 0.005). Patients who underwent coronary artery bypass grafting, even more than 12 months before index surgery, had a 79% reduction in risk of death if they had PMI (P = 0.01). Multivariable analysis revealed preoperative definitive diagnosis of coronary artery disease (P = 0.001) and significant valvular disease (P = 0.03) were associated with increased risk of PMI. Congestive heart failure less than 1 yr before index vascular surgery (P = 0. 0002) and increased intraoperative use of blood (P = 0.007) were associated with cardiac death. The history of coronary artery bypass grafting reduced the risk of cardiac death (P = 0.04) in patients with PMI. CONCLUSIONS: The in-hospital cardiac mortality rate is high for patients who undergo vascular surgery and experience clinically significant PMI. Stress of surgery (increased intraoperative bleeding and aortic, peripheral vascular, and emergency surgery), poor preoperative cardiac functional status (congestive heart failure, lower ejection fraction, diagnosis of coronary artery disease), and preoperative history of coronary artery bypass grafting are the factors that determine perioperative cardiac morbidity and mortality rates.     

Age and sex differences in perioperative myocardial infarction after cardiac surgery

We investigate age and sex differences in acute myocardial infarction (AMI) after cardiac surgery in a prospective study of 2038 consecutive patients undergoing cardiac surgery with cardiopulmonary bypass. An age of ≥ 70 years implied changes in the type of AMI from the ST-segment elevation myocardial infarction (STEMI) to non-ST-segment elevation myocardial infarction (non-STEMI). Men were more likely than women to suffer from AMI after cardiac surgery (11.8% vs. 5.6%), as a result of the higher frequency of STEMI (6% of men vs. 1.8% of women; P < 0.001) in both age groups. A troponin-I (Tn-I) peak was significantly higher in patients ≥ 70 years old. In-hospital mortality was higher in patients ≥ 70 (7.3%) than in those < 70 years old (3.3%), because of the increased mortality observed in men with non-AMI (2.1% vs. 6.3%) and women with STEMI (0% vs. 28.6%) and non-STEMI (0% vs. 36.8%, P < 0.05). Old age was associated with a higher frequency of non-STEMI, Tn-I peak, mortality and length of stay in the intensive care unit (ICU). Regardless of age, men more often suffer from AMI (particularly STEMI). AMI in women had a notable impact on excess mortality and ICU stay observed in patients ≥ 70 years of age. Clinical and Tn-I peak differences are expected in relation to age and gender after AMI post-cardiac surgery.     

Preoperative assessment of cardiac risk and perioperative cardiac management in noncardiac surgery

More than 27 million Americans undergo noncardiac surgery annually. Cardiac complications can be a major source of morbidity and mortality in the perioperative period. Preoperative risk stratification, intraoperative ischemia monitoring and postoperative surveillance help to predict, identify and efficiently treat these adverse events. A renewed emphasis on preoperative evaluation has helped to identify patients at an increased risk for adverse cardiac events and thus, implement noninvasive or invasive cardio protective strategies in an attempt to minimize these complications. In this review we briefly describe the current evidence on perioperative management of patients presenting for noncardiac surgery. As the surgeon will remain one of the first to evaluate patients before noncardiac surgery it is essential he/she be well versed with this information.     

Semiquantitative dipyridamole myocardial stress perfusion imaging for cardiac risk assessment before noncardiac vascular surgery: a meta-analysis

BACKGROUND: Semiquantitative dipyridamole myocardial perfusion scintigraphy may provide better estimates of perioperative cardiac risk than nonquantitative scintigraphy. OBJECTIVE: The purpose of this study was to conduct a metaanalysis of semiquantitive dipyridamole myocardial perfusion scintigraphy for the prediction of perioperative myocardial infarction and cardiac death in patients undergoing noncardiac vascular surgery. METHODS: The data sources used were MEDLINE (from 1975 to 1999), citation lists, and correspondence with study authors. We included studies that evaluated preoperative semiquantitative dipyridamole myocardial perfusion scintigraphy in patients undergoing noncardiac vascular surgery. For each study, we calculated results on the basis of the proportion of myocardial segments with reversible perfusion defects. The complications of interest were cardiac death and nonfatal myocardial infarction. We calculated likelihood ratios (LRs) and areas under the receiver operating characteristic curves for individual studies and for the combined data. DATA SYNTHESIS: We identified nine studies involving a total of 1179 patients with 82 cardiac complications (complication rate, 7.0%). Most studies were grade C in quality. Normal scans significantly reduced the likelihood of perioperative cardiac complications (LR, 0.42; 95% CI, 0.20 to 0.88). Fixed defects reduced the likelihood of complications, but the effect was not statistically significant (LR, 0.51; 95% CI, 0.24 to 1.1). Reversibility in less than 20% of myocardial segments did not change the likelihood of perioperative cardiac complications (LR, 1.3, 95% CI, 0.88 to 1.9). LRs for increasing extents of reversibility were: 20% to 29% reversibility (LR, 1.6; 95% CI, 1.0 to 2.6), 30% to 39% reversibility (LR, 2.9; 95% CI, 1.6 to 5.1), 40% to 49% reversibility (LR, 2.9; 95% CI, 1.4 to 6.2), and 50% or more reversibility (LR, 11; 95% CI, 5.8 to 20). The pooled area under the receiver operating characteristic curve was 0.78 (95% CI, 0.65 to 0.89). Heterogeneity was found among study results, but exclusion of heterogeneous studies did not significantly change the summary results. CONCLUSION: Reversible defects in less than 20% of myocardial segments do not significantly alter the risk of perioperative cardiac complications. Greater extents of reversibility on dipyridamole myocardial stress perfusion imaging increase the risk of perioperative complications after noncardiac vascular surgery, but the quality and amount of data regarding greater extents of reversibility are limited.     

Algorithm of cardiac risk assessment before vascular surgery

THE OBJECT: to detect the informative value of algorithm of cardiac risk assessment recommended by American Heart Association compared with original standard enlarged protocol. Overall 456 patients underwent vascular operations. First group consisted of 198 patients who were examined according original enlarged protocol; other 258 patients (2nd group) were examined with AHA protocol. At 1st group 41% patients didn't need myocardial revascularization (according coronarography results), preventive coronary bypass surgery was performed at 32% patients. At 2nd group coronarography was performed at 133 (51%) patients according risk factors stratification and stress-examination results. Preventive coronary bypass surgery was performed at 97 patients; 27 patients refused this recommendation. Enlarged protocol increases in 2.6 times the odds of unnecessary invasive procedure. It is concluded that AHA algorithm permits to reduce in 2 times and more the number of invasive diagnostic procedures compared with standard enlarged protocol; AHA algorithm increases the clinical and economic effectiveness.     

The value of silent myocardial ischemia monitoring in the prediction of perioperative myocardial infarction in patients undergoing peripheral vascular surgery

Real-time electrocardiographic monitoring for silent myocardial ischemia was performed on 200 patients undergoing peripheral vascular surgery to try to better define those at high risk of perioperative myocardial infarction. The patients were divided into those undergoing abdominal aortic aneurysm or lower extremity revascularization procedures (group I, n = 120) and those undergoing carotid artery endarterectomy (group II, n = 80). Silent ischemia was detected during the preoperative, intraoperative, or post-operative periods in 60.8% of group I and 67.5% of group II patients. Six group I and three group II patients suffered an acute perioperative myocardial infarction with two cardiac deaths. In both groups I and II a variety of parameters based on monitoring of silent myocardial ischemia were compared between the subgroups of patients who had myocardial infarction and those who did not. The results show that in both groups there was a significantly (p less than or equal to 0.05) greater total duration of perioperative ischemic time, total number of perioperative ischemic episodes, and total duration of perioperative ischemic time as a percent of total monitoring time in patients who suffered a perioperative myocardial infarction compared to those who did not. Multivariate logistic regression analysis of preoperative characteristics in all 200 patients showed the occurrence of preoperative silent myocardial ischemia and angina at rest to be the only significant predictors of perioperative myocardial infarction. Thus perioperative monitoring for silent myocardial ischemia might noninvasively identify those patients undergoing peripheral vascular surgery who are at increased risk for perioperative myocardial infarction, permitting implementation of timely preventive measures in selected patients.     

Effects of myocardial infarction on perioperative cardiac complications

Of 1104 consecutive noncardiac operations on 981 patients using general anesthesia, 63 were performed on 53 patients who had had a previous myocardial infarction. Patients with a previous infarct were compared to those with no prior infarct to determine the influence of a previous infarct on perioperative cardiac complications. Two of the 53 patients with a previous myocardial infarction (3.8%) had perioperative myocardial infarction, compared to 0.4% (4/928) of patients with no prior history of myocardial infarction (P less than 0.05). Ventricular tachycardia (P less than 0.05) and cardiac death (P less than 0.01) were more frequent in patients with a previous myocardial infarction compared to those with no prior infarct. All patients with a previous myocardial infarction who developed cardiac complications underwent vascular procedures (P less than 0.005) and were over 77 years of age. The two patients who reinfarcted experienced intraoperative hypotension (P less than 0.05). Fourteen of the 53 patients with a history of a myocardial infarction (26.4%) had previous coronary artery bypass surgery; no perioperative cardiac complications occurred in these patients.     

Peripheral vascular surgery: update on the perioperative non-surgical management for high cardiac risk patients

This review of the recent literature regarding perioperative management in peripheral vascular surgery emphasizes some of the important features for the 2003 state-of-the-art on non surgical perioperative care for these high cardiac risk patients. The most adapted preoperative cardiac evaluation for each patient is guided by its individual risk factors and clinical history. Perioperative medication should nowadays consist of pre- and postoperative beta-blockers and acetyl salicylic acid, both reducing cardiac morbidity and mortality. Neuraxial locoregional anaesthesia techniques are reasonable alternatives to general anaesthesia because of their potential advantages, by reducing postoperative inflammatory response and reducing procoagulating activity, and increasing peripheral vascular graft patency, but the individual benefit/risk balance has always to be evaluated for patients submitted to aggressive antithrombotic therapy. During the postoperative course, early detection and treatment of postoperative myocardial ischemia or infarction by ST wave changes and/or cardiac enzyme control has to be considered.     

The role of state-of-the-art echocardiography in the assessment of myocardial injury during and following cardiac surgery.

Use of intraoperative echocardiography during open heart surgery, transesophageal probes, high-frequency transducers, and color Doppler imaging provide important diagnostic information to surgeons and anesthesiologists. Early detection of myocardial ischemia, assessment of valvular disorders, and the ability to monitor for intracardiac air are among the most important roles of intraoperative transesophageal echocardiography. Large prospective studies are necessary to evaluate whether these changes affect the outcome of patients undergoing coronary artery bypass grafting in terms of morbidity, mortality, hospital length of stay, and functional recovery. The application of new techniques such as contrast-enhanced transesophageal echocardiography helps to assess the adequacy of cardioplegia distribution and, thus, myocardial protection during cardiopulmonary bypass, which has a significant influence on outcomes as well.     

Silent myocardial ischemia monitoring predicts late as well as perioperative cardiac events in patients undergoing vascular surgery.

In a previous study we have shown that perioperative monitoring for silent myocardial ischemia can noninvasively identify those patients undergoing peripheral vascular surgery who are at significantly increased risk for perioperative myocardial infarction. In the present study a group of 385 patients undergoing peripheral vascular surgery was studied long-term as well as short-term to determine whether perioperative monitoring for silent ischemia can identify those patients who are at significantly increased risk of late cardiac death or late cardiac complications as well as those patients at increased risk of perioperative myocardial infarction. All patients were monitored before, during, and after operation and were divided into two groups on the basis of results of monitoring: patients whose total duration of silent ischemia as a percentage of the total duration of perioperative monitoring was 1% or greater (group I, n = 120) and those for whom this value was less than 1% (group II, n = 265). Among patients in group I 13.3% (16 of 120) suffered a perioperative myocardial infarction in contrast to only 1.1% (3 of 265) patients in group II (p less than 0.001). Multivariate logistic regression analysis of preoperative and perioperative characteristics showed that the presence of a total perioperative percent time ischemic 1% or greater and age were the only significant predictors of perioperative myocardial infarction.(ABSTRACT TRUNCATED AT 250 WORDS)     

Which stress test is superior for perioperative cardiac risk stratification in patients undergoing major vascular surgery?

OBJECTIVE: to compare the additional prognostic value of Dobutamine Stress Echocardiography (DSE), Dipyridamole Stress Echocardiography (DiSE) and Perfusion Scintigraphy (DTS) on clinical risk factors in patients undergoing major vascular surgery. DESIGN: retrospective analysis. MATERIALS: 2204 consecutive patients who underwent DSE (n=1093), DiSE (n=394), or DTS (n=717) testing before major vascular surgery were studied. METHODS: primary endpoint was a composite of cardiac death and non-fatal myocardial infarction (MI). Logistic regression analysis was performed to evaluate the relation between cardiac risk factors, stress test results and the incidence of the composite endpoint. RESULTS: there were 138 patients (6.3%) with cardiac death or MI. Patients with 0, 1-2, and 3 or more risk factors experienced respectively 3.0, 5.7 and 17.4% cardiac events. We found no statistically significant difference in the predictive value of a positive test result for DiSE and DSE (Odds ratio (OR) of 37.1 [95% CI, 8.1-170.1] vs 9.6 [95% CI, 4.9-18.4]; p=0.12), whereas a positive test result for DTS had significantly lower prognostic value (OR=1.95 [95% CI, 1.2-3.2]). CONCLUSION: a result of stress echocardiography effectively stratified patients into low- and high-risk groups for cardiac complications, irrespective of clinical risk profile. In contrast, the prognostic value of DTS results was more likely to be dependent on patients' clinical risk profile.     

Relationship of unrecognised myocardial infarction, diabetes mellitus and type of surgery to postoperative cardiac outcomes in vascular surgery.

OBJECTIVES: to evaluate preoperative clinical, surgical and instrumental variables as predictors of postoperative cardiac events in patients undergoing different types of elective major vascular surgery. MATERIAL AND METHODS: on the basis of an algorithm including clinical and test echocardiographic data, we prospectively stratified 604 consecutive patients into low, intermediate and high-risk groups. The value of the variables in predicting postoperative cardiac events was assessed by means of multivariate analysis. RESULTS: there were 16 major postoperative cardiac events and six of 16 postoperative deaths were cardiac related (1%). Significant predictors of cardiac complications were unrecognised myocardial infarction (odds ratio - (OR) 5.6), coronary artery disease (OR 2.5), severe hypertension (OR 2.1) and peripheral vascular surgery (OR 1.9). In the intermediate-risk group, the best correlates with cardiac complications were unrecognised myocardial infarction (OR 3.3) and diabetes (OR 2.5). CONCLUSIONS: our results suggest the importance of identifying patients with unrecognised ischaemic heart disease and of using aggressive perioperative protocols for managing diabetic patients undergoing peripheral vascular procedures.     

急性心肌梗死康复期病人非心脏手术的麻醉处理

目的评价急性心肌梗死后进行非心脏手术围手术期的麻醉处理.方法普外科和普胸外科病人12例,(67±4)岁.心梗发生至手术间隔72-175d.麻醉选择为硬膜外阻滞或复合全身麻醉,保留硬膜外导管术后镇痛.结果病人均顺利度过手术期.术中心电图监测无缺血性ST-T改变.术后病人镇痛效果良好.随访至出院,无一例出现急性心衰和心肌梗死.结论急性心肌梗死康复期病人进行非心脏手术应放宽时间限制.急性心梗康复期病人进行非心脏手术的危险不仅与心梗发生的时间间隔相关,还取决于冠心病的严重程度、病人对体力活动的耐受程度及外科手术性质.充分的术前准备对稳定围手术期心脏功能十分重要.硬膜外阻滞复合全身麻醉是冠心病病人非心脏手术较适合的麻醉方法.     

Characteristics of patients at risk for perioperative myocardial infarction after infrainguinal bypass surgery: An exploratory study

Patients requiring infrainguinal bypass surgery often have diffuse atherosclerotic disease, and perioperative myocardial infarction (MI) is a potentially lethal complication that is not uncommon in these patients. To establish additional clinical characteristics that might be useful in identifying patients who require more extensive cardiac evaluation, we conducted an exploratory case-control study comparing 22 patients who had a perioperative MI following elective infrainguinal bypass surgery with 191 control subjects whose bypasses were uneventful. In addition to previously recognized risk factors (e.g., history of angina or prior MI), we examined the association of perioperative MI with (1) results of common preoperative laboratory tests and ECG, (2) preoperative use of certain medications, and (3) intraoperative factors that might be anticipated prior to surgery (e.g., duration of surgery or type of anesthesia). Perioperative MI was associated not only with a history of angina, prior MI, or coronary artery disease but also with the need for certain cardiac medications, higher white blood cell (WBC) counts, ST-segment depression, left bundle branch block, and lengthy surgical procedures. Multiple logistic regression analysis identified the following factors as being independently associated with perioperative MI: preoperative antiarrhythmic agents (odds ratio [OR]=26.4,p 0.006), nitrates (OR=8.4,p=0.006), calcium channel blockers (OR=5.5,p=0.04), and aspirin (OR=6.8,p <0.01) and ST-segment depression (OR=11.8,p=0.01), WBC count (OR=1.27/1000,p=0.005), and duration of surgery (OR=2.2/hr,p=0.0001). In patients undergoing infrainguinal bypass surgery, perioperative MI is associated not only with a history of previous cardiac events and ECG evidence of ischemia but also with regular use of certain cardiac medications, higher WBC counts, and longer surgical procedures. Incorporation of these variables into current methods of risk assessment might improve their predictive value sufficiently to provide an objective, inexpensive means of distinguishing patients who warrant extensive preoperative cardiac evaluation from those who do not.We are indebted to Maryann Barry, RN, for helping to collect the preoperative ECG reports and to Timothy Heeren, PhD, Boston University School of Public Health, for advice regarding statistical analysis.     

Validation of an updated approach to preoperative cardiac risk assessment in vascular surgery

To validate a more selective approach to cardiac assessment which consisted of limiting stress testing and coronary revascularization to highly selected patients and limiting coronary revascularization to patients with severe cardiac symptoms, we compared two time periods (1994-1995 and 2000-2001) with respect to cardiac work-up and cardiac morbidity and mortality. Our method involved a retrospective review of patients undergoing vascular procedures from 2000 to 2001 at a single institution. In group 1 (2000-2001), 139 operations were performed on 120 patients. In group 2 (1994-1995), 145 procedures were performed on 109 patients. Preoperative stress testing was reduced from 42 patients (29%) in group 2 to 20 patients (14%) in group 1 (P < 0.01), and preoperative coronary artery bypass grafting was reduced from six (4.1%) to two (1.4%) (P < 0.28), respectively. Coronary angiography was unchanged: 8 (5.8%) patients in group 1 versus 11 (7.9%) patients in group 2 (P = NS). Two (1.4%) patients underwent percutaneous transluminal coronary angioplasty in group 1 and group 2. Cardiac event rates were similar: seven (5%) patients in both groups. Cardiac death was not significantly different: two (1.4%) in group 1 versus one (0.7%) in group 2. Cardiac morbidity and mortality after major vascular surgery remain the same despite using a more selective cardiac stress protocol.