Methodology of serial ECG classification using an adaptation of the NOVACODE for Q wave myocardial infarction in the Bypass Angioplasty Revascularization Investigation (BARI)

Effect of random deferral of percutaneous coronary intervention in patients with diabetes and stable ischaemic heart disease

BACKGROUND

In stable ischaemic heart disease (SIHD), measurement of fractional flow reserve (FFR) to guide selection of lesions for percutaneous coronary intervention (PCI) reduces death and myocardial infarction (MI) compared with angiographic guidance. However, it is unknown if the improved outcomes are due to avoidance of stenting of physiologically insignificant lesions or are a by-product of placing fewer stents.

METHODS

We developed a Monte Carlo simulation using the PCI strata of the Bypass Angioplasty Revascularization Investigation 2 Diabetes study to investigate how random deferral of PCI impacts outcomes. To simulate deferral, a randomly selected group of patients randomised to PCI were removed and replaced by an equal number of randomly selected patients randomised to intensive medical therapy (IMT) using a random number generator in Python's NumPy module. The primary endpoint was the rate of death or non-fatal MI at 1 year.

RESULTS

Death/MI at 1 year occurred in 8.3% of 798 patients in the PCI group and 5.1% of 807 patients in the IMT control group (p=0.02). Following 10 000 iterations of random replacement of 10%, 20%, 30% or 40% of PCI patients with randomly selected IMT patients, the rate of death/MI at 1 year progressively declined from 8.3% to 8.0%, 7.6%, 7.3% and 7.0%, respectively.

CONCLUSIONS

In this simulation model, random deferral of PCI procedures in SIHD progressively reduced death/MI as the percentage of procedures deferred increases. FFR-guided deferral of PCI may improve outcomes as a result of placing fewer stents and be unrelated to the haemodynamic severity of lesions.

Design, methodology and baseline characteristics of the Women's Ischemia Syndrome Evaluation-Coronary Vascular Dysfunction (WISE-CVD)

A significant number of women with signs and symptoms of ischemia with no obstructive coronary artery disease (INOCA) have coronary vascular dysfunction detected by invasive coronary reactivity testing (CRT). However, the noninvasive assessment of coronary vascular dysfunction has been limited.

METHODS

The Women's Ischemia Syndrome Evaluation-Coronary Vascular Dysfunction (WISE-CVD) was a prospective study of women with suspected INOCA aimed to investigate whether (1) cardiac magnetic resonance imaging (CMRI) abnormalities in left ventricular morphology and function and myocardial perfusion predict CRT measured coronary microvascular dysfunction, (2) these persistent CMRI abnormalities at 1-year follow-up predict persistent symptoms of ischemia, and (3) these CMRI abnormalities predict cardiovascular outcomes. By design, a sample size of 375 women undergoing clinically indicated invasive coronary angiography for suspected INOCA was projected to complete baseline CMRI, a priori subgroup of 200 clinically indicated CRTs, and a priori subgroup of 200 repeat 1-year follow-up CMRIs.

RESULTS

A total of 437 women enrolled between 2008 and 2015, 374 completed baseline CMRI, 279 completed CRT, and 214 completed 1-year follow-up CMRI. Mean age was 55± 11 years, 93% had 20%-50% coronary stenosis, and 7% had <20% stenosis by angiography.

CONCLUSIONS

The WISE-CVD study investigates the utility of noninvasive CMRI to predict coronary vascular dysfunction in comparison to invasive CRT, and the prognostic value of CMRI abnormalities for persistent symptoms of ischemia and cardiovascular outcomes in women with INOCA. WISE-CVD will provide new understanding of a noninvasive imaging modality for future clinical trials.

Ascertainment of Silent Myocardial Infarction in Patients Undergoing Percutaneous Coronary Intervention (from the GLOBAL LEADERS Trial)

Q-wave myocardial infarction (QWMI) comprises 2 entities. First, a clinically evident MI, which can occur spontaneously or be related to a coronary procedure. Second, silent MI which is incidentally detected on serial electrocardiographic (ECG) assessment. The prevalence of silent MI after percutaneous coronary intervention (PCI) in the drug-eluting stent era has not been fully investigated. The GLOBAL LEADERS is an all-comers multicenter trial which randomized 15,991 patients who underwent PCI to 2 antiplatelet treatment strategies. The primary end point was a composite of all-cause death or nonfatal new QWMI at 2-years follow-up. ECGs were collected at discharge, 3-month and 2-year visits, and analyzed by an independent ECG core laboratory following the Minnesota code. All new QWMI were further reviewed by a blinded independent cardiologist to identify a potential clinical correlate by reviewing clinical information. Of 15,968 participants, ECG information was complete in 14,829 (92.9%) at 2 years. A new QWMI was confirmed in 186 (1.16%) patients. Transient new Q-waves were observed in 28.5% (53 of 186) of them during the follow-up. The majority of new QWMI (78%, 146 of 186) were classified as silent MI due to the absence of a clinical correlate. Silent MI accounted for 22.1% (146 of 660) of all MI events. The prevalence of silent MI did not differ significantly between treatment strategies (experimental vs reference: 0.88% vs 0.98%, p = 0.5027). In conclusion, we document the prevalence of silent MI in an all-comers population undergoing PCI in this large-scale randomized trial.

Increased Hazard of Myocardial Infarction With Insulin-Provision Therapy in Actively Smoking Patients With Diabetes Mellitus and Stable Ischemic Heart Disease: The BARI 2D (Bypass Angioplasty Revascularization Investigation 2 Diabetes) Trial

Background

In the BARI 2D (Bypass Angioplasty Revascularization Investigation 2 Diabetes) trial, randomization of diabetic patients with stable ischemic heart disease to insulin provision (IP) therapy, as opposed to insulin sensitization (IS) therapy, resulted in biochemical evidence of impaired fibrinolysis but no increase in adverse clinical outcomes. We hypothesized that the prothrombotic effect of IP therapy in combination with the hypercoagulable state induced by active smoking would result in an increased risk of myocardial infarction (MI).

Methods and Results

We analyzed BARI 2D patients who were active smokers randomized to IP or IS therapy. The primary end point was fatal or nonfatal MI. PAI‐1 (plasminogen activator inhibitor 1) activity was analyzed at 1, 3, and 5 years. Of 295 active smokers, MI occurred in 15.4% randomized to IP and in 6.8% randomized to IS over the 5.3 years (P=0.023). IP therapy was associated with a 3.2‐fold increase in the hazard of MI compared with IS therapy (hazard ratio: 3.23; 95% confidence interval, 1.43–7.28; P=0.005). Baseline PAI‐1 activity (19.0 versus 17.5 Au/mL, P=0.70) was similar in actively smoking patients randomized to IP or IS therapy. However, IP therapy resulted in significantly increased PAI‐1 activity at 1 year (23.0 versus 16.0 Au/mL, P=0.001), 3 years (24.0 versus 18.0 Au/mL, P=0.049), and 5 years (29.0 versus 15.0 Au/mL, P=0.004) compared with IS therapy.

Conclusions

Among diabetic patients with stable ischemic heart disease who were actively smoking, IP therapy was independently associated with a significantly increased hazard of MI. This finding may be explained by higher PAI‐1 activity in active smokers treated with IP therapy.

Clinical Trial Registration

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00006305.

Associations of obesity and body fat distribution with incident atrial fibrillation in the biracial health aging and body composition cohort of older adults

Obesity is a well-recognized risk factor for atrial fibrillation (AF), yet adiposity measures other than body mass index (BMI) have had limited assessment in relation to AF risk. We examined the associations of adiposity measures with AF in a biracial cohort of older adults. Given established racial differences in obesity and AF, we assessed for differences by black and white race in relating adiposity and AF.

METHODS

We analyzed data from 2,717 participants of the Health, Aging, and Body Composition Study. Adiposity measures were BMI, abdominal circumference, subcutaneous and visceral fat area, and total and percent fat mass. We determined the associations between the adiposity measures and 10-year incidence of AF using Cox proportional hazards models and assessed for their racial differences in these estimates.

RESULTS

In multivariable-adjusted models, 1-SD increases in BMI, abdominal circumference, and total fat mass were associated with a 13% to 16% increased AF risk (hazard ratio [HR] 1.14, 95% CI 1.02-1.28; HR 1.16, 95% CI 1.04-1.28; and HR 1.13, 95% CI 1.002-1.27). Subcutaneous and visceral fat areas were not significantly associated with incident AF. We did not identify racial differences in the associations between the adiposity measures and AF.

CONCLUSION

Body mass index, abdominal circumference, and total fat mass are associated with risk of AF for 10years among white and black older adults. Obesity is one of a limited number of modifiable risk factors for AF; future studies are essential to evaluate how obesity reduction can modify the incidence of AF.

Electrocardiographic PR interval and adverse outcomes in older adults: the Health, Aging, and Body Composition study

BACKGROUND

The electrocardiographic PR interval increases with aging, differs by race, and is associated with atrial fibrillation (AF), pacemaker implantation, and all-cause mortality. We sought to determine the associations between PR interval and heart failure, AF, and mortality in a biracial cohort of older adults.

METHODS AND RESULTS

The Health, Aging, and Body Composition (Health ABC) Study is a prospective, biracial cohort. We used multivariable Cox proportional hazards models to examine PR interval (hazard ratios expressed per SD increase) and 10-year risks of heart failure, AF, and all-cause mortality. Multivariable models included demographic, anthropometric, and clinical variables in addition to established cardiovascular risk factors. We examined 2722 Health ABC participants (aged 74±3 years, 51.9% women, and 41% black). We did not identify significant effect modification by race for the outcomes studied. After multivariable adjustment, every SD increase (29 ms) in PR interval was associated with a 13% greater 10-year risk of heart failure (95% confidence interval, 1.02-1.25) and a 13% increased risk of incident AF (95% confidence interval, 1.04-1.23). PR interval >200 ms was associated with a 46% increased risk of incident heart failure (95% confidence interval, 1.11-1.93). PR interval was not associated with increased all-cause mortality.

CONCLUSIONS

We identified significant relationships of PR interval to heart failure and AF in older adults. Our findings extend prior investigations by examining PR interval and associations with adverse outcomes in a biracial cohort of older men and women.

The Bypass Angioplasty Revascularization Investigation 2 Diabetes randomized trial of different treatment strategies in type 2 diabetes mellitus with stable ischemic heart disease: impact of treatment strategy on cardiac mortality and myocardial infarction

BACKGROUND

The Bypass Angioplasty Revascularization Investigation 2 Diabetes (BARI 2D) trial in 2368 patients with stable ischemic heart disease assigned before randomization to percutaneous coronary intervention or coronary artery bypass grafting strata reported similar 5-year all-cause mortality rates with insulin sensitization versus insulin provision therapy and with a strategy of prompt initial coronary revascularization and intensive medical therapy or intensive medical therapy alone with revascularization reserved for clinical indication(s). In this report, we examine the predefined secondary end points of cardiac death and myocardial infarction (MI).

METHODS AND RESULTS

Outcome data were analyzed by intention to treat; the Kaplan-Meier method was used to assess 5-year event rates. Nominal P values are presented. During an average 5.3-year follow-up, there were 316 deaths (43% were attributed to cardiac causes) and 279 first MI events. Five-year cardiac mortality did not differ between revascularization plus intensive medical therapy (5.9%) and intensive medical therapy alone groups (5.7%; P=0.38) or between insulin sensitization (5.7%) and insulin provision therapy (6%; P=0.76). In the coronary artery bypass grafting stratum (n=763), MI events were significantly less frequent in revascularization plus intensive medical therapy versus intensive medical therapy alone groups (10.0% versus 17.6%; P=0.003), and the composite end points of all-cause death or MI (21.1% versus 29.2%; P=0.010) and cardiac death or MI (P=0.03) were also less frequent. Reduction in MI (P=0.001) and cardiac death/MI (P=0.002) was significant only in the insulin sensitization group.

CONCLUSIONS

In many patients with type 2 diabetes mellitus and stable ischemic coronary disease in whom angina symptoms are controlled, similar to those enrolled in the percutaneous coronary intervention stratum, intensive medical therapy alone should be the first-line strategy. In patients with more extensive coronary disease, similar to those enrolled in the coronary artery bypass grafting stratum, prompt coronary artery bypass grafting, in the absence of contraindications, intensive medical therapy, and an insulin sensitization strategy appears to be a preferred therapeutic strategy to reduce the incidence of MI.

Sodium-hydrogen exchange inhibition by cariporide to reduce the risk of ischemic cardiac events in patients undergoing coronary artery bypass grafting: results of the EXPEDITION study

BACKGROUND

The EXPEDITION study addressed the efficacy and safety of inhibiting the sodium hydrogen exchanger isoform-1 (NHE-1) by cariporide in the prevention of death or myocardial infarction (MI) in patients undergoing coronary artery bypass graft surgery. The premise was that inhibition of NHE-1 limits intracellcular Na accumulation and thereby limits Na/Ca-exchanger-mediated calcium overload to reduce infarct size.

METHODS

High-risk coronary artery bypass graft surgery patients (n = 5,761) were randomly allocated to receive either intravenous cariporide (180 mg in a 1-hour preoperative loading dose, then 40 mg per hour over 24 hours and 20 mg per hour over the subsequent 24 hours) or placebo. The primary composite endpoint of death or MI was assessed at 5 days, and patients were followed for as long as 6 months.

RESULTS

At 5 days, the incidence of death or MI was reduced from 20.3% in the placebo group to 16.6% in the treatment group (p = 0.0002). Paradoxically, MI alone declined from 18.9% in the placebo group to 14.4% in the treatment group (p = 0.000005), while mortality alone increased from 1.5% in the placebo group to 2.2% with cariporide (p = 0.02). The increase in mortality was associated with an increase in cerebrovascular events. Unlike the salutary effects that were maintained at 6 months, the difference in mortality at 6 months was not significant.

CONCLUSIONS

The EXPEDITION study is the first phase III myocardial protection trial in which the primary endpoint was achieved and proof of concept demonstrated. As a result of increased mortality associated with an increase in cerebrovascular events, it is unlikely that cariporide will be used clinically. The findings suggest that sodium hydrogen exchanger isoform-1 inhibition holds promise for a new class of drugs that could significantly reduce myocardial injury associated with ischemia-reperfusion injury.

Computerized serial comparison of electrocardiograms: program performance in myocardial infarction

Serial comparison of electrocardiograms (ECGs) can provide a useful clinical function by reporting to the editing cardiologist the diagnostic changes that have occurred since the previous ECG. This program detects "significant measurement differences" in each of the diagnostic categories to detect these changes. We evaluated the accuracy and use of this serial comparison program by comparing the diagnostic results of the program with those of an expert cardiologist using a database of ECGs obtained from patients with symptoms admitted to the hospital and other laboratory results consistent with acute myocardial infarction. We found that the level of agreement between the computer and the cardiologist was much higher when a current ECG was compared with a previous that had been edited by the cardiologist than when that same ECG was analyzed in isolation.

Increased creatine kinase MB level predicts postoperative mortality after cardiac surgery independent of new Q waves

BACKGROUND

Recent consensus statements recommend cardiac enzyme release as the essential criterion for diagnosing myocardial infarction. However, the outcome implications of cardiac enzyme release in patients undergoing coronary artery bypass grafting are controversial.

METHODS

Eight hundred patients were followed for 30 days after elective on-pump coronary artery bypass grafting in a multicenter, prospective, randomized trial of the anti-C5 complement antibody pexelizumab. Data from centralized electrocardiography and creatine kinase MB analyses were examined for any association with death or severe left ventricular dysfunction.

RESULTS

More than half of the 800 patients had peak creatine kinase MB levels of more than 5 times the upper limit of 5 ng/mL set by the core laboratory. The median peak value was 29 ng/mL. The incidence of the combined outcome (death or severe left ventricular dysfunction) was 1.7% if the peak creatine kinase MB level was less than 25 ng/mL and 18.0% if 100 ng/mL or greater (P < .01). Similarly, the incidence of new Q-wave myocardial infarction was 3.9% if the peak creatine kinase MB level was less than 25 ng/mL and 30.6% if 100 ng/mL or greater (P < .01). In a multivariate analysis that included preoperative and intraoperative factors, as well as peak enzyme release and Q-wave myocardial infarction, the strongest predictor of the combined outcome was a peak creatine kinase MB level of 100 ng/mL or greater. New Q-wave myocardial infarction did not significantly predict the combined outcome.

CONCLUSIONS

Increased postoperative peak creatine kinase MB level, especially when 20 times or more of the upper limit of normal, indicates increased risk of severe postoperative left ventricular dysfunction and mortality within 30 days of coronary artery bypass grafting. High peak enzyme level is a stronger predictor of adverse outcomes than is postoperative Q-wave myocardial infarction in this population.

Impact of pexelizumab, an anti-C5 complement antibody, on total mortality and adverse cardiovascular outcomes in cardiac surgical patients undergoing cardiopulmonary bypass

BACKGROUND

During cardiac surgery requiring cardiopulmonary bypass, pro-inflammatory complement pathways are activated by exposure of blood to bio-incompatible surfaces of the extracorporeal circuit and reperfusion of ischemic organs. Complement activation promotes the generation of additional inflammatory mediators thereby exacerbating tissue injury. We examined the safety and efficacy of a C5 complement inhibitor for attenuating inflammation-mediated cardiovascular dysfunction in cardiac surgical patients undergoing cardiopulmonary bypass.

METHODS

Pexelizumab (Alexion Pharmaceuticals, Inc, Cheshire, CT), a recombinant, single-chain, anti-C5 monoclonal antibody, was evaluated in a randomized, double-blinded, placebo-controlled, multicenter trial that involved 914 patients undergoing coronary artery bypass grafting with or without valve surgery requiring cardiopulmonary bypass.

RESULTS

Pexelizumab was administered intravenously as a bolus (2.0 mg/kg) or bolus plus infusion (2.0 mg/kg plus 0.05 mg/kg/h for 24 hours), and inhibited complement activation. There were no statistically significant differences between placebo-treated and pexelizumab-treated patients in the primary endpoint (composite of death, or new Q-wave, or non-Q-wave [myocardial-specific isoform of creatine kinase > 60 ng/mL] myocardial infarction, or left ventricular dysfunction, or new central nervous system deficit). However, post hoc analysis revealed a reduction in the composite of death or myocardial infarction (myocardial-specific isoform of creatine kinase >/= 100 ng/mL) for the isolated coronary artery bypass grafting, bolus plus infusion subgroup on POD 4 (p = 0.007) and on POD 30 (p = 0.004).

CONCLUSIONS

Pexelizumab had no statistically significant effect on the primary endpoint. However, the reduction in death or myocardial infarction (myocardial-specific isoform of creatine kinase >/= 100 ng/mL) as revealed in the post hoc analysis in the isolated coronary artery bypass grafting bolus plus infusion subpopulation, suggests that further investigation of anti-C5 therapy for ameliorating complement-mediated inflammation and myocardial injury is warranted.

Impact of sodium-hydrogen exchange inhibition by cariporide on death or myocardial infarction in high-risk CABG surgery patients: results of the CABG surgery cohort of the GUARDIAN study

OBJECTIVES

To evaluate the effects of cariporide on all-cause mortality or myocardial infarction at 36 days in patients at risk of myocardial necrosis after coronary artery bypass graft surgery.

METHODS

In the coronary artery bypass graft cohort of the GUARD During Ischemia Against Necrosis trial, patients > or =18 years who required urgent coronary artery bypass graft, repeat coronary artery bypass graft, or had a history of unstable angina and > or =2 risk factors (age >65 years, female gender, diabetes mellitus, ejection fraction <35%, or left main or 3-vessel disease) were randomized to placebo (n = 743) or cariporide 20 mg (n = 736), 80 mg (n = 705), or 120 mg (n = 734). A 1-hour intravenous infusion was initiated shortly before surgery and administered every 8 hours for 2 to 7 days. Patients were followed up for 6 months. A nonparametric covariance analysis was used to calculate the primary efficacy endpoint.

RESULTS

Baseline characteristics were similar between treatment groups. The cariporide 20- and 80-mg groups had event rates similar to placebo. The endpoint of all-cause mortality or myocardial infarction at day 36 was significant with cariporide 120 mg versus placebo (event rate 12.2% vs 16.2%; P =.027). The risk reduction was evident on postoperative day 1 (3.3% vs 6.5%; P =.005) and was maintained at 6 months (event rate 15.0% vs 18.6%; P =.033). Cariporide was well tolerated, and most adverse events were mild and transient in this high-risk population.

CONCLUSIONS

Clinical benefit with cariporide 120 mg was observed early after treatment initiation and continued for 6 months postsurgery, suggesting that sodium-hydrogen exchange inhibition with cariporide is cardioprotective in patients undergoing high-risk coronary artery bypass graft surgery.

A review of the GUARDIAN trial results: clinical implications and the significance of elevated perioperative CK-MB on 6-month survival

BACKGROUND

The Guard During Ischemia Against Necrosis (GUARDIAN) trial was designed to determine whether cariporide, a selective sodium-hydrogen exchanger inhibitor, reduces the combined incidence of all-cause mortality and myocardial infarction (MI) in patients at risk of myocardial necrosis and to assess the safety and tolerability of this drug.

METHODS AND RESULTS

The study population consisted of 11,590 patients who were hospitalized for an acute coronary syndrome or were undergoing high-risk percutaneous coronary intervention or coronary artery bypass grafting (CABG). Patients were enrolled and randomized to one of three doses of cariporide (20, 80, or 120 mg), or placebo, administered as a 60-minute infusion every 8 hours for two to seven days. At day 36, patients treated with cariporide 120 mg demonstrated a 10% risk reduction in death or MI compared with placebo (p = 0.12). At this dose, patients undergoing CABG experienced a 25% risk reduction in death or MI (p = 0.03), which was sustained through six months (p = 0.033). The improvement resulted primarily from a 32% risk reduction in nonfatal MI (p = 0.007). Cariporide was well tolerated; most adverse events were mild and transient. Data from the GUARDIAN trial indicate that myocardial muscle creatine kinase isoenzyme (CK-MB) values of >10 times the upper limit of normal during the initial 48 hours after CABG are associated with significantly increased six-month mortality (p < 0.001); the six-month mortality risk is similar to that observed in acute coronary syndrome patients, even after adjustment for baseline variables known to impact long-term prognosis.

CONCLUSIONS

Although the results of the GUARDIAN trial failed to demonstrate overall clinical benefit, cariporide 120 mg reduced the rate of death and MI in patients undergoing CABG. Cariporide may provide a cardioprotective benefit in CABG patients at high-risk of myocardial necrosis.

Increased mortality after coronary artery bypass graft surgery is associated with increased levels of postoperative creatine kinase-myocardial band isoenzyme release: results from the GUARDIAN trial

OBJECTIVES

We sought to determine if elevated cardiac serum biomarkers after coronary artery bypass graft surgery (CABG) are associated with increased medium-term mortality and to identify patients that may benefit from better postoperative myocardial protection.

BACKGROUND

The relationship between the magnitude of cardiac serum protein elevation and subsequent mortality after CABG is not well defined, partly because of the lack of large, prospectively studied patient cohorts in whom postoperative elevations of cardiac serum markers have been correlated to medium- and long-term mortality.

METHODS

The GUARD during Ischemia Against Necrosis (GUARDIAN) study enrolled 2,918 patients assigned to the entry category of CABG and considered as high risk for myocardial necrosis. Creatine kinase-myocardial band (CK-MB) isoenzyme measurements were obtained at baseline and at 8, 12, 16 and 24 h after CABG.

RESULTS

The unadjusted six-month mortality rates were 3.4%, 5.8%, 7.8% and 20.2% for patients with a postoperative peak CK-MB ratio (peak CK-MB value/upper limits of normal [ULN] for laboratory test) of < 5, > or = 5 to <10, > or =10 to < 20 and > or =20 ULN, respectively (p < 0.0001). The relationship remained statistically significant after adjustment for ejection fraction, congestive heart failure, cerebrovascular disease, peripheral vascular disease, cardiac arrhythmias and the method of cardioplegia delivery. Receiver operating characteristic curve analysis revealed an area under the curve of 0.648 (p < 0.001); the optimal cut-point to predict six-month mortality ranged from 5 to 10 ULN.

CONCLUSIONS

Progressive elevation of the CK-MB ratio in clinically high-risk patients is associated with significant elevations of medium-term mortality after CABG. Strategies to afford myocardial protection both during CABG and in the postoperative phase may serve to improve the clinical outcome.

Comparative 30-day economic and clinical outcomes of platelet glycoprotein IIb/IIIa inhibitor use during elective percutaneous coronary intervention: Prairie ReoPro versus Integrilin Cost Evaluation (PRICE) Trial

OBJECTIVES

This study examined the economics, pharmacodynamics, and clinical outcomes among patients randomly assigned to receive either abciximab (ReoPro, Centocor, Inc, Malvern, Pa, and Eli Lilly & Company, Indianapolis, Ind) or eptifibatide (Integrilin, COR Therapeutics, Inc, South San Francisco, Calif, and Key Pharmaceuticals, Inc, Kenilworth, NJ) therapy during elective percutaneous coronary intervention (PCI).

BACKGROUND

Clinical and safety outcomes after elective PCI with a high-dose eptifibatide treatment strategy have not previously been systematically evaluated. In addition, comparative economic and pharmacodynamic studies of platelet glycoprotein (GP) IIb/IIIa receptor antagonists during PCI are sparse.

METHODS

This randomized, double-blind study assessed the 30-day economic and clinical outcomes of 320 consecutive patients undergoing elective coronary balloon angioplasty or stent implantation who were randomly assigned to receive adjunct abciximab (n = 163) or eptifibatide (n = 157) therapy. The primary study end point was total in-hospital costs based on an intention-to-treat analysis. A secondary end point included 30-day total hospital costs. A platelet aggregometry substudy was performed on 155 patients (abciximab: n = 74 and eptifibatide: n = 81) with use of the Ultegra Rapid Platelet Function Assay.

RESULTS

Baseline demographic, angiographic, and procedural variables were similar between the two treatment groups. The median and interquartile ranges of total in-hospital costs were $8268 ($6505, $9958) and $7207 ($5659, $9307), respectively, between the abciximab- and eptifibatide-treated patients (P =.009). Median total costs at 30 days were $8336 ($6505, $10,126) and $7207 ($5659, $9431), respectively, between the abciximab- and eptifibatide-treated groups (P =.009). The composite secondary clinical end points (death/nonfatal myocardial infarction/urgent revascularization) occurred in 4.9% versus 5.1% of patients, respectively, by hospital discharge (P =.84) and in 5.6% versus 6.3% of patients, respectively, at 30 days (P =.95) in the abciximab and eptifibatide groups. With the eptifibatide dose used, early and more durable platelet inhibition was achieved compared with abciximab (P <.00001).

CONCLUSION

In drug dosages and patients similar to those enrolled in the current study, eptifibatide achieved durable platelet inhibition throughout drug infusion and was associated with lower in-hospital and 30-day costs compared with abciximab in patients undergoing elective PCI.

Inhibition of the sodium-hydrogen exchanger with cariporide to prevent myocardial infarction in high-risk ischemic situations. Main results of the GUARDIAN trial. Guard during ischemia against necrosis (GUARDIAN) Investigators

BACKGROUND

The transmembrane sodium/hydrogen exchanger maintains myocardial cell pH integrity during myocardial ischemia but paradoxically may precipitate cell necrosis. The development of cariporide, a potent and specific inhibitor of the exchanger, prompted this investigation of the potential of the drug to prevent myocardial cell necrosis.

METHODS AND RESULTS

A total of 11 590 patients with unstable angina or non-ST-elevation myocardial infarction (MI) or undergoing high-risk percutaneous or surgical revascularization were randomized to receive placebo or 1 of 3 doses of cariporide for the period of risk. The trial failed to document benefit of cariporide over placebo on the primary end point of death or MI assessed after 36 days. Doses of 20 and 80 mg every 8 hours had no effect, whereas a dose of 120 mg was associated with a 10% risk reduction (98% CI 5.5% to 23.4%, P=0.12). With this dose, benefit was limited to patients undergoing bypass surgery (risk reduction 25%, 95% CI 3.1% to 41.5%, P=0.03) and was maintained after 6 months. No effect was seen on mortality. The rate of Q-wave MI was reduced by 32% across all entry diagnostic groups (2.6% versus 1.8%, P=0.03), but the rate of non-Q-wave MI was reduced only in patients undergoing surgery (7.1% versus 3.8%, P=0.005). There were no increases in clinically serious adverse events.

CONCLUSIONS

No significant benefit of cariporide could be demonstrated across a wide range of clinical situations of risk. The trial documented safety of the drug and suggested that a high degree of inhibition of the exchanger could prevent cell necrosis in settings of ischemia-reperfusion.

Association between new electrocardiographic abnormalities after coronary revascularization and five-year cardiac mortality in BARI randomized and registry patients

There are few data comparing the relative frequency of new electrocardiographic (ECG) abnormalities after coronary artery bypass grafting (CABG) compared with percutaneous transluminal coronary angioplasty (PTCA) and their association with long-term cardiac mortality. The study population consisted of 3,373 patients who were either randomized or eligible to be randomized to CABG or PTCA in the BARI trial. The frequency of new postprocedural ECG abnormalities was significantly greater after a CABG procedure than after PTCA. The incidence of new postprocedural major Q waves, ST-segment elevation, and T-wave abnormalities were significantly more frequent after CABG. After PTCA (n = 1,869), the 5-year cardiac mortality rates associated with the new development of major Q waves, ST-segment elevation, ST-segment depression, T-wave abnormalities, or no abnormality was 18.1%, 8.5%, 8.9%, 6.0%, and 5.4%, respectively. After CABG (n = 1,427), 5-year cardiac mortality rates were 8.0%, 4.2%, 3.8%, 2.8%, and 3.7%, respectively. The adjusted relative risk of 5-year cardiac mortality for new Q-wave abnormalities was 2.6 after CABG (p <0.04) and 4.6 after PTCA (p <0.01). Thus, patients who undergo CABG have more postinitial procedural ECG abnormalities than patients who undergo PTCA. Cardiac mortality is significantly increased by the new development of postprocedural Minnesota code Q-wave abnormalities regardless of whether patients undergo CABG or PTCA.

All-artery multigraft coronary artery bypass grafting with only internal thoracic arteries possible and safe: a randomized trial

BACKGROUND

The internal thoracic artery (ITA) bypass to the left anterior descending coronary artery is of proven benefit in multigraft coronary artery bypass. Total ITA grafts, if reoperation is averted by avoiding saphenous vein grafts (SVGs), are attractive. The safety of the total ITA graft operation (all-ITA) is a concern.

METHODS

A randomized trial of multiple-ITA bypass graftings with the use of bilateral sequential ITA without SVGs was performed. Control patients received 1 ITA plus SVG. Inclusion criteria were those used in the Coronary Artery Surgery Study, extended to age 76 years, and any angina class, except emergent. One hundred sixty-two patients were randomized (81 patients per group) from January 1, 1990, to December 31, 1994.

RESULTS

Baseline traits were similar as were cross-clamp times, pump times, and number of arteries bypassed (average, 4.3 arteries). Patients who received multiple ITA grafts had no myocardial infarctions, per reference laboratory. One patient died, and 2 patients returned for bleeding. The ITA-SVG group had similar results. The all-ITA group experienced successful completion in 93% of cases. Complications did not differ from control patients.

CONCLUSIONS

Early and 5-year outcomes were not different between the all-ITA group and the ITA with SVGs group. We believe experienced surgeons can safely extend the ITA to multibypass coronary artery bypass without use of SVG to achieve an all-ITA operation.

The effect of previous coronary-artery bypass surgery on the prognosis of patients with diabetes who have acute myocardial infarction. Bypass Angioplasty Revascularization Investigation Investigators

BACKGROUND

Acute myocardial infarction in patients with diabetes is associated with high mortality. We studied whether previous revascularization by coronary-artery bypass grafting (CABG), as compared with percutaneous transluminal coronary angioplasty (PTCA), influences the prognosis in such patients.

METHODS

We classified all patients eligible for the Bypass Angioplasty Revascularization Investigation who underwent coronary revascularization within three months after entry into the study according to whether they had diabetes and whether they had undergone CABG, either initially or after PTCA. The protective effect of CABG with regard to mortality in the presence and in the absence of subsequent spontaneous Q-wave myocardial infarction was estimated with the use of Cox regression models.

RESULTS

Among the 641 patients with diabetes and the 2962 without diabetes, the cumulative five-year rates of death were 20 percent and 8 percent, respectively (P<0.001), and the five-year rates of spontaneous Q-wave myocardial infarction were 8 percent and 4 percent (P<0.001). CABG greatly reduced the risk of death after spontaneous Q-wave myocardial infarction in the patients with diabetes (relative risk, 0.09; 95 percent confidence interval, 0.03 to 0.29). Among patients with diabetes who had undergone CABG but did not have spontaneous Q-wave myocardial infarctions, the corresponding relative risk of death was 0.65 (95 percent confidence interval, 0.45 to 0.94). Among the patients without diabetes, no protective effect of CABG was evident.

CONCLUSIONS

Among patients with diabetes, previous coronary bypass surgery, as compared with coronary angioplasty, has a highly favorable influence on prognosis after acute myocardial infarction and a smaller beneficial effect among patients who do not have infarction. These findings should influence the type of coronary revascularization procedure selected for patients with diabetes who have multivessel coronary artery disease.

Design of a trial evaluating myocardial cell protection with cariporide, an inhibitor of the transmembrane sodium-hydrogen exchanger: the Guard During Ischemia Against Necrosis (GUARDIAN) trial

Inhibition of the sodium-hydrogen exchanger (NHE) is a powerful experimental tool to inhibit sodium and calcium accumulation within the ischemic myocyte and halt progression of cell ischemia to cell necrosis. This paper describes the protocol and rationale of a first large-scale clinical trial designed to evaluate the safety and efficacy of cariporide, a novel specific and potent inhibitor of the exchanger.

Frequency of early occlusion and stenosis in a left internal mammary artery to left anterior descending artery bypass graft after surgery through a median sternotomy on conventional bypass: benchmark for minimally invasive direct coronary artery bypass

BACKGROUND

Uncertainty exists regarding the frequency of early occlusion when the left internal mammary artery (LIMA) is anastomosed to the left anterior descending artery (LAD) through a sternotomy with conventional coronary artery bypass grafting (CABG). The issue has gained importance for comparison with less invasive surgical approaches in which operative exposure may be limited and graft anastomosis more difficult.

METHODS AND RESULTS

Data were analyzed from the International Multicenter Aprotinin Graft Patency Experience (IMAGE) trial in which 617 patients underwent conventional CABG of the LAD with a LIMA between April 1993 and May 1995. Coronary angiography was performed a mean of 10.8 days postoperatively. Patients were randomized to receive intraoperative aprotinin, an inhibitor of several serine proteinases, or placebo. Because no differences existed in patency rates of LIMA grafts between patients who received aprotinin and placebo, both groups were analyzed collectively. On coronary angiography, the LIMA was widely patent (<50% stenosis) in 561 patients (91%), had > or = 50% and <99% stenosis in 48 patients (7.8%), and was occluded in 8 patients (1.3%). Therefore, the LIMA was patent in 609 patients (98.7%). Conclusions-In the IMAGE trial, the largest and most contemporary early angiographic analysis of CABG available, early patency of the LIMA was >98% when anastomosed to the LAD. These data provide an important benchmark for less invasive surgical approaches in which the LIMA is anastomosed to the LAD.

Analyses of coronary graft patency after aprotinin use: results from the International Multicenter Aprotinin Graft Patency Experience (IMAGE) trial

OBJECTIVE

We examined the effects of aprotinin on graft patency, prevalence of myocardial infarction, and blood loss in patients undergoing primary coronary surgery with cardiopulmonary bypass.

METHODS

Patients from 13 international sites were randomized to receive intraoperative aprotinin (n = 436) or placebo (n = 434). Graft angiography was obtained a mean of 10.8 days after the operation. Electrocardiograms, cardiac enzymes, and blood loss and replacement were evaluated.

RESULTS

In 796 assessable patients, aprotinin reduced thoracic drainage volume by 43% (P < .0001) and requirement for red blood cell administration by 49% (P < .0001). Among 703 patients with assessable saphenous vein grafts, occlusions occurred in 15.4% of aprotinin-treated patients and 10.9% of patients receiving placebo (P = .03). After we had adjusted for risk factors associated with vein graft occlusion, the aprotinin versus placebo risk ratio decreased from 1.7 to 1.05 (90% confidence interval, 0.6 to 1.8). These factors included female gender, lack of prior aspirin therapy, small and poor distal vessel quality, and possibly use of aprotinin-treated blood as excised vein perfusate. At United States sites, patients had characteristics more favorable for graft patency, and occlusions occurred in 9.4% of the aprotinin group and 9.5% of the placebo group (P = .72). At Danish and Israeli sites, where patients had more adverse characteristics, occlusions occurred in 23.0% of aprotinin- and 12.4% of placebo-treated patients (P = .01). Aprotinin did not affect the occurrence of myocardial infarction (aprotinin: 2.9%; placebo: 3.8%) or mortality (aprotinin: 1.4%; placebo: 1.6%).

CONCLUSIONS

In this study, the probability of early vein graft occlusion was increased by aprotinin, but this outcome was promoted by multiple risk factors for graft occlusion.

Reproducibility of computerized ECG measurements and coding in a nonhospitalized elderly population

The standard 12-lead electrocardiogram (ECG) is used in many epidemiologic studies to diagnose and predict cardiovascular disease. In view of this, knowledge about the reproducibility of ECG measurements and coding is essential. Minute-to-minute, day-to-day, and year-to-year variability of ECG measurements, composite scores, and Minnesota Code classification were assessed by use of a computer program, in 101 nonhospitalized elderly men and women. Interval ECG measurements were more reproducible than amplitude measurements. The best reproducibility was found for the overall QTc interval (coefficient of variation 3.1%, 4.0%, and 5.2% for the minute-to-minute, day-to-day, and year-to-year groups, respectively) and the poorest was found for the Cardiac Infarction Injury Score (coefficient of variation 67.1%, 78.5%, and 94.3%, respectively). Minnesota Code discrepancies occurred in 16%, 19%, and 22% of the ECGs in the minute-to-minute, day-to-day, and year-to-year groups, respectively. Reproducibility within specific code categories was much better. Overall, variability tended to increase with time. In the routine setting, electrode positioning had relatively little effect on total variability.

Comparison of the various electrocardiographic scoring codes for estimating anatomically documented sizes of single and multiple infarcts of the left ventricle

It is clinically important to estimate the size of a myocardial infarction (MI) to predict patient prognosis, to determine the ability of a therapy to limit its size, and to evaluate its effect on left ventricular function. Various electrocardiographic methods have been used for these purposes but their accuracies have not been compared with each other using an identical reference population of anatomically measured infarcts. The capability of 4 electrocardiographic scoring methods (the Selvester score, the Minnesota code, the Novacode, and the Cardiac Infarction Injury Score) to estimate MI size was compared using anatomic MI size in a group of 100 deceased patients. All patients had a standard 12-lead electrocardiogram of sufficient quality to perform manual waveform measurements and without confounding factors such as ventricular hypertrophy, fascicular block, or bundle branch block. The location and size of the left ventricular infarction was measured postmortem using the anatomic method of Ideker et al. All methods' size estimates correlated best with anatomic MI size in the anterior location (r = 0.65 to 0.89). The Selvester score was superior in estimating the sizes of inferior (r = 0.70) and posterolateral (r = 0.74) infarcts. For multiple infarcts all methods performed poorly (r = 0.18 to 0.44).

Rationale and design of the Myocardial Ischemia Reduction with Aggressive Cholesterol Lowering (MIRACL) study that evaluates atorvastatin in unstable angina pectoris and in non-Q-wave acute myocardial infarction

The goal of the Myocardial Ischemia Reduction with Aggressive Cholesterol Lowering (MIRACL) study is to determine whether early, rapid, and profound cholesterol lowering therapy with atorvastatin can reduce early recurrent ischemic events in patients with unstable angina or non-Q-wave acute myocardial infarction. Within 1 to 4 days of hospitalization for one of these conditions, 2,100 patients will be randomly assigned to receive atorvastatin, 80 mg/day, or placebo in a double-blind design. Both groups receive dietary counseling. Over a 16-week follow-up period, the primary outcome measure is the time to occurrence of an ischemic event, defined as death, nonfatal acute myocardial infarction, cardiac arrest with resuscitation, or recurrent symptomatic myocardial ischemia requiring emergency rehospitalization. Secondary outcome measures are the time to occurrence and incidence of each of the primary outcome components, as well as nonfatal stroke, worsening angina, congestive heart failure requiring hospitalization, and need for coronary revascularization not anticipated before randomization. The sample size of 1,050 patients in each group is expected to provide 95% power to detect a 30% reduction in the primary outcome measure with a 5% level of significance. The results of the MIRACL study will determine the utility of profound cholesterol lowering as an early intervention in acute coronary syndromes.

Myocardial infarction and cardiac mortality in the Bypass Angioplasty Revascularization Investigation (BARI) randomized trial

BACKGROUND

Cardiac mortality and myocardial infarction (MI) rates are used to evaluate the efficacy of coronary artery bypass grafting (CABG) and percutaneous transluminal coronary angioplasty (PTCA). We compared 5-year cardiac mortality and MI rates in 1829 patients with multivessel disease randomized to CABG or PTCA.

METHODS AND RESULTS

The 5-year cardiac mortality rate was 8.0% in patients assigned to PTCA compared with 4.9% in those assigned to CABG (relative risk [RR] of 1.55 with a 95% confidence interval [CI] of 1.07 to 2.23; P=.022). In a subgroup of 1476 nondiabetic patients, there were no significant differences between treatment groups in cardiac mortality either overall (4.6% versus 4.2%; RR= 1.04, 95% CI, 0.65 to 1.66; P=.908) or in subgroups based on symptoms, left ventricular function, number of diseased vessels, or stenotic proximal left anterior descending artery. The two treatment groups had similar event rates for the combined end point of cardiac death or MI. The RR for cardiac mortality in 264 patients who sustained an MI compared with those who did not was 5.9 (P<.001). MIs were more common after CABG during index hospitalization (P=.004), but in the PTCA group, they were more common after discharge (P<.001).

CONCLUSIONS

The Bypass Angioplasty Revascularization Investigation (BARI) trial indicates 5-year cardiac mortality in patients with multivessel disease was significantly greater after initial treatment with PTCA than with CABG. The difference was manifest in diabetic patients on drug therapy. There were no significant differences overall for the composite end point of cardiac mortality or MI between treatment groups or for cardiac mortality in nondiabetic patients regardless of symptoms, left ventricular function, number of diseased vessels, or stenotic proximal left anterior descending artery.

Influence of diabetes on 5-year mortality and morbidity in a randomized trial comparing CABG and PTCA in patients with multivessel disease: the Bypass Angioplasty Revascularization Investigation (BARI)

BACKGROUND

Patients with diabetes mellitus have increased morbidity and mortality after coronary revascularization. The Bypass Angioplasty Revascularization Investigation (BARI), a trial of percutaneous transluminal coronary angioplasty (PTCA) versus coronary artery bypass graft surgery (CABG) in patients with multivessel disease, reported a 5-year survival advantage of CABG over PTCA in patients with treated diabetes mellitus (TDM). This report examines these findings in more detail.

METHODS AND RESULTS

Eighteen clinical centers randomly assigned 1829 patients with multivessel coronary disease to undergo initial CABG or PTCA. Patients were followed an average of 5.4 years. TDM was defined as a history of diabetes with use of oral hypoglycemic agents or insulin at study entry. Nineteen percent of the randomized population (353 patients) met these criteria. TDM patients had more unfavorable baseline characteristics than other patients, but among TDM patients, these characteristics were similar between the CABG and PTCA groups. Better average 5.4-year survival with CABG was due to reduced cardiac mortality (5.8% versus 20.6%, P=.0003), which was confined to those receiving at least one internal mammary artery graft.

CONCLUSIONS

Patients with TDM assigned to an initial strategy of CABG have a striking reduction in cardiac mortality compared with PTCA. Long-term internal mammary artery graft patency may contribute to this improved outcome by reducing the fatality of follow-up myocardial infarction.