Prevention of reinfarction and sudden death

There are many potential approaches to the prevention of reinfarction and sudden death, but the proof of benefit as yet is confined to the use of beta-adrenoceptor blocking drugs and coronary artery bypass surgery. In selected cases, aspirin, anticoagulants and antiarrhythmics drugs may prevent one or other of these complications, but other categories of drugs, including the calcium antagonists, seem at present unsuccessful. Greatest hope for the future lies in the development of strategies that limit infarct size.

Natural history of myocardial infarction--relevance for secondary prevention

Numerous variables have been identified as having prognostic value after infarction. The significance of each of these depends both on the time after the event when the observation is made and the length of follow-up. Although much prognostic information has been published, its validity is difficult to establish because the criteria for infarction have seldom been stated, the effect of treatment has been ignored and the case material has been either ill-defined or atypical. Most of the most powerful predictors of medium and long-term prognosis are not susceptible to correction, e.g. age, previous myocardial infarction, cardiomegaly, enzyme levels, intraventricular conduction defects and indices of left ventricular dysfunction. Others, e.g. "warning arrhythmias" may be treatable but there is, as yet, no evidence that suppressing them improves prognosis. The most clinically relevant prognostic factors are those which are of relatively high predictive value but are potentially correctable. These include smoking, hypertension, diabetes, life-threatening arrhythmias, and exercise-induced ischaemia, as manifested by angina and ST changes. Secondary prevention is most likely to be successful if appropriate approaches are aimed at specific subsets. Thus, beta-blockade, anti-arrhythmic therapy, platelet active agents, and surgery may each be beneficial in different although possibly overlapping sub-sets. Even if it is shown that any one of these forms of therapy produces a statistical benefit when given to the whole post-infarct population, it does not follow that it should be given to all members of such a population.

Translation of clinical trials into clinical practice

The results of well-conducted clinical trials should be translated into practice but there is good evidence that this is not happening. There are a number of reasons for this - ignorance of doctors and patients, uncertainty as to the applicability of trials to individual patients, indolence and inefficiency on the part of practitioners, and financial considerations. More attention needs to be paid to correct all these factors.

Diltiazem in acute myocardial infarction treated with thrombolytic agents: a randomised placebo-controlled trial. Incomplete Infarction Trial of European Research Collaborators Evaluating Prognosis post-Thrombolysis (INTERCEPT)

BACKGROUND

Diltiazem reduces non-fatal reinfarction and refractory ischaemia after non-Q-wave myocardial infarction, an acute coronary syndrome similar to the incomplete infarction that occurs after successful reperfusion. We postulated that this agent would reduce cardiac events in patients after acute myocardial infarction treated initially with thrombolytic agents-a clinical application previously unexplored with heart-rate-lowering calcium antagonists.

METHODS

A prospective, randomised, double-blind, sequential trial was done in 874 patients with acute myocardial infarction, but without congestive heart failure, who first received thrombolytic agents. Patients received either 300 mg oral diltiazem once daily, or placebo, initiated within 36-96 h of infarct onset, and given for up to 6 months. The trial primary endpoint was the cumulative first event rate of cardiac death, non-fatal reinfarction, or refractory ischaemia. Additional prespecified endpoints included several composites of non-fatal cardiac events (non-fatal reinfarction combined with refractory ischaemia, all recurrent ischaemia, or the need for myocardial revascularisation). The diagnosis of ischaemia, whether refractory or recurrent, and the need for myocardial revascularisation, was always based on objective electrocardiographical evidence of ischaemia, either at rest or on exertion.

RESULTS

For the trial primary endpoint, 131 events occurred in the 444 placebo patients and 97 events in the 430 diltiazem patients (hazard ratio 0.79; 95% CI, 0.61-1.02; p=0.07). For non-fatal cardiac events, diltiazem treatment was associated with a relative decrease (0.76; 0.58-1.00) in the combined event rate of non-fatal reinfarction and refractory ischaemia. There was a similar decrease in the composite non-fatal endpoints of non-fatal reinfarction combined with all recurrent ischaemia (0.80; 0.64-1.00) and non-fatal reinfarction combined with the need for myocardial revascularisation (0.67; 0.46-0.96). The need for myocardial revascularisation alone was significantly reduced by 42% (0.61; 0.39-0.96). No major safety issues were encountered.

CONCLUSIONS

Diltiazem did not reduce the cumulative occurrence of cardiac death, non-fatal reinfarction, or refractory ischaemia during a 6-month follow-up, but did reduce all composite endpoints of non-fatal cardiac events, especially the need for myocardial revascularisation.

Depressed heart rate variability identifies postinfarction patients who might benefit from prophylactic treatment with amiodarone: a substudy of EMIAT (The European Myocardial Infarct Amiodarone Trial)

OBJECTIVES

This substudy tested a prospective hypothesis that European Myocardial Infarct Amiodarone Trial (EMIAT) patients with depressed heart rate variability (HRV) benefit from amiodarone treatment.

BACKGROUND

The EMIAT randomized 1,486 survivors of acute myocardial infarction (MI) aged < or =75 years with left ventricular ejection fraction (LVEF) < or =40% to amiodarone or placebo. Despite a reduction of arrhythmic mortality on amiodarone, all-cause mortality was not changed.

METHODS

Heart rate variability was assessed from prerandomization 24-h Holter tapes in 1,216 patients (606 on amiodarone). Two definitions of depressed HRV were used: standard deviation of normal to normal intervals (SDNN) < or =50 ms and HRV index < or =20 units. The survival of patients with depressed HRV was compared in the placebo and amiodarone arms. A retrospective analysis investigated the prospective dichotomy limits. All tests were repeated in five subpopulations: patients with first MI, patients on beta-adrenergic blocking agents, patients with LVEF < or =30%, patients with Holter arrhythmia and patients with baseline heart rate > or =75 beats/min.

RESULTS

Centralized Holter processing produced artificially high SDNN but accurate HRV index values. Heart rate variability index was < or =20 U in 363 (29.9%) patients (183 on amiodarone) with all-cause mortality 22.8% on placebo and 17.5% on amiodarone (23.2% reduction, p = 0.24) and cardiac arrhythmic mortality 12.8% on placebo and 4.4% on amiodarone (66% reduction, p = 0.0054). Among patients with prospectively defined depressed HRV, the largest reduction of all-cause mortality was in patients with first MI (placebo 17.9%, amiodarone 10.3%, 42.5% reduction, p = 0.079) and in patients with heart rate < or =75 beats/min (placebo 29.0%, amiodarone 19.3%, 33.7% reduction, p = 0.075). Among patients with first MI and depressed HRV, amiodarone treatment was an independent predictor of survival in a multivariate Cox analysis. The retrospective analysis found a larger reduction of mortality on amiodarone in 313 (25.7%) patients with HRV index < or =19 U: 23.9% on placebo and 17.1% on amiodarone (28.4% reduction, p = 0.15). This was more expressed in patients with first MI: 49.4% mortality reduction on amiodarone (p = 0.046), on beta-blockers: 69.0% reduction (p = 0.047) and with heart rate > or =75 beats/min: 37.9% reduction (p = 0.054).

CONCLUSION

Measurement of HRV in a large set of centrally processed Holter recordings is feasible with robust methods of assessment. Patients with LVEF < or =40% and depressed HRV benefit from prophylactic antiarrhythmic treatment with amiodarone. However, this finding needs confirmation in an independent data set before clinical practice is changed.

The agonising negative trend in monitoring of clinical trials

Randomised clinical trials are undertaken in the hope of showing positive benefits of a new treatment, but on occasion quite the opposite trend can occur, If the interim data suggest possible negative (harmful) effects of a new treatment. The handling of such emerging negative trends is among the most complicated and ethically challenging scenarios in monitoring clinical trials through repeated interim analyses. Statistical methods are helpful to detect the point of no likely beneficial effect, and the point that separates neutral results from harmful results. However, in practice the decision whether (and exactly when) to stop such a trial involves a complex of other issues that depends on the context of the disease, the treatment being assessed, and the current practice of medicine. Owing to this complexity, an Independent Data and Safety Monitoring Board (DSMB) is best suited to deal with such a situation. Prediction of whether a negative trend will emerge in any trial is not possible. Negative trends were not anticipated in the cardiovascular trials and the trials of lung-cancer prevention described here. In the light of these experiences, all trials and their DSMBs should consider ahead of time the possibility of unexpectedly harmful results, and should document appropriately the statistical guidelines and the decision-making process required to cope with such undesirable events.

Effect of mivazerol on perioperative cardiac complications during non-cardiac surgery in patients with coronary heart disease: the European Mivazerol Trial (EMIT)

BACKGROUND

Mivazerol is a drug with alpha2-agonist properties that reduces post-ganglionic noradrenaline availability and spinal efferent sympathetic output.

METHODS

A double-blind randomized placebo-controlled trial was conducted in 61 European centers during a 2.5-yr period on 2,854 patients: 1,897 with coronary heart disease and 957 patients without overt coronary heart disease but classified as at high risk for it. The present analysis was restricted to those patients with previous known coronary heart disease of whom 48% had vascular surgery, 32% non-vascular thoracic or abdominal surgery, and 20% orthopedic surgery. Mivazerol or placebo were given intravenously from the induction of anesthesia for up to 72 h.

RESULTS

In the 1,897 patients with established coronary heart disease, mivazerol did not reduce the primary endpoint--the combination of myocardial infarction or death--or all-cause deaths significantly. A preplanned subgroup analysis of 904 patients with known coronary heart disease undergoing vascular surgery showed that there were fewer primary endpoints in those receiving mivazerol (risk ratio [RR], 0.67; 95% CL, 0.45-0.98; P = 0.037) and fewer cardiac deaths (6 of 454 vs. 18 of 450: RR, 0.33; 95% confidence limits, 0.13-0.82; P = 0.017). The all-cause death rate was also decreased (RR, 0.41; 95% CL, 0.18-0.91; P = 0.024), although there was no significant reduction in myocardial infarction.

CONCLUSION

The alpha2-adrenergic agonist, mivazerol, did not alter the rates of myocardial infarction or cardiac death in patients with known coronary heart disease undergoing noncardiac surgery. However, it may have protected patients undergoing vascular surgery from further coronary events, and a specific study of such patients is now indicated.

Amiodarone interaction with beta-blockers: analysis of the merged EMIAT (European Myocardial Infarct Amiodarone Trial) and CAMIAT (Canadian Amiodarone Myocardial Infarction Trial) databases. The EMIAT and CAMIAT Investigators

BACKGROUND

Investigations with in vitro and animal models suggest an interaction between amiodarone and beta-blockers. The objective of this work was to explore if an interaction with beta-blocker treatment plays a role in the decrease of cardiac arrhythmic deaths with amiodarone in patients recovered from an acute myocardial infarction.

METHODS AND RESULTS

A pooled database from 2 similar randomized clinical trials, the European Amiodarone Myocardial Infarction Trial (EMIAT) and the Canadian Amiodarone Myocardial Infarction Trial (CAMIAT), was used. Four groups of post-myocardial infarction patients were defined: beta-blockers and amiodarone used, beta-blockers used alone, amiodarone used alone, and neither used. All analyses were done on an intention-to-treat basis. Unadjusted and adjusted relative risks for all-cause mortality, cardiac death, arrhythmic cardiac death, nonarrhythmic cardiac death, arrhythmic death, or resuscitated cardiac arrest were lower for patients receiving beta-blockers and amiodarone than for those without beta-blockers, with or without amiodarone. The interaction was statistically significant for cardiac death and arrhythmic death or resuscitated cardiac arrest (P=0.05 and 0.03, respectively). Findings were consistent across subgroups.

CONCLUSIONS

These findings are based on a post hoc analysis. However, they confirm prior results from in vitro and animal experiments suggesting an interaction between beta-blockers and amiodarone. In practice, not only is the adjunct of amiodarone to beta-blockers not hazardous, but beta-blocker therapy should be continued if possible in patients in whom amiodarone is indicated.

Identification of post acute myocardial infarction patients with potential benefit from prophylactic treatment with amiodarone. A substudy of EMIAT (the European Myocardial Infarct Amiodarone Trial)

AIMS

To perform a retrospective analysis of subgroups of patients enrolled into the European Myocardial Infarct Amiodarone Trial (EMIAT) in order to identify patients who might benefit from prophylactic amiodarone treatment and patients in whom amiodarone might be harmful.

METHODS

Baseline characteristics of the 1486 patients enrolled in EMIAT were used to investigate the all-cause mortality effect of amiodarone (intention-to-treat) in patients with a left ventricular ejection fraction 30-40% and < 30%, in patients with and without arrhythmia signs on Holter recordings, in patients with high and low baseline resting heart rate, in patients on and off beta-blocker treatment, and in a combination of these groups.

RESULTS

A univariate analysis suggested that all-cause mortality is reduced on amiodarone in patients with an ejection fraction < 30%, with arrhythmia on the initial Holter, on beta-blocker treatment, and with an increased initial heart rate. A trend towards an increase of all-cause mortality was noted in patients with an ejection fraction 30-40%, without arrhythmia on Holter, off beta-blockers, and with a low baseline heart rate. A multivariate analysis suggested that the univariate observations are mutually additive.

CONCLUSIONS

The study might serve as a basis for future prospective trials where amiodarone could be tested in patients with a recent myocardial infarction, having a reduced left ventricular ejection fraction, a high initial heart rate, and taking beta-blockers.

Randomised trial of effect of amiodarone on mortality in patients with left-ventricular dysfunction after recent myocardial infarction: EMIAT. European Myocardial Infarct Amiodarone Trial Investigators

BACKGROUND

Ventricular arrhythmias are a major cause of death after myocardial infarction, especially in patients with poor left-ventricular function. Previous attempts to identify and suppress arrhythmias with various antiarrhythmic drugs failed to reduce or actually increase mortality. Amiodarone is a powerful antiarrhythmic drug with several potentially beneficial actions, and has shown benefit in several small-scale studies. We postulated that this drug might reduce mortality in patients at high risk of death after myocardial infarction because of impaired ventricular function, irrespective of whether they had ventricular arrhythmias.

METHODS

The European Myocardial Infarct Amiodarone Trial (EMIAT) was a randomised double-blind placebo-controlled trial to assess whether amiodarone reduced all-cause mortality (primary endpoint) and cardiac mortality and arrhythmic death (secondary endpoints) in survivors of myocardial infarction with a left-ventricular ejection fraction (LVEF) of 40% or less. Intention-to-treat and on-treatment analyses were done.

FINDINGS

EMIAT enrolled 1486 patients (743 in the amiodarone group, 743 in the placebo group). Median follow-up was 21 months. All-cause mortality (103 deaths in the amiodarone group, 102 in the placebo group) and cardiac mortality did not differ between the two groups. However, in the amiodarone group, there was a 35% risk reduction (95% CI 0-58, p = 0.05) in arrhythmic deaths.

INTERPRETATION

Our findings do not support the systematic prophylactic use of amiodarone in all patients with depressed left-ventricular function after myocardial infarction. However, the lack of proarrhythmia and the reduction in arrhythmic death support the use of amiodarone in patients for whom antiarrhythmic therapy is indicated.

A comparison of aspirin and anticoagulation following thrombolysis for myocardial infarction (the AFTER study): a multicentre unblinded randomised clinical trial

OBJECTIVE

To compare aspirin with anticoagulation with regard to risk of cardiac death and reinfarction in patients who received anistreplase thrombolysis for myocardial infarction.

DESIGN

A multicentre unblinded randomised clinical trial.

SETTING

38 hospitals in six countries.

SUBJECTS

1036 patients who had been treated with anistreplase for myocardial infarction were randomly assigned to either aspirin (150 mg daily) or anticoagulation (intravenous heparin followed by warfarin or other oral anticoagulant). The trial was stopped earlier than originally intended because of the slowing rate of recruitment.

MAIN OUTCOME MEASURE

Cardiac death or recurrent myocardial infarction at 30 days.

RESULTS

After 30 days cardiac death or reinfarction, occurred in 11.0% (57/517) of the patients treated with anticoagulation and 11.2% (58/519) of the patients treated with aspirin (odds ratio 1.02, 95% confidence interval 0.69 to 1.50, P = 0.92). Corresponding findings at three months were 13.2% (68/517) and 12.1% (63/519) (0.91, 0.63 to 1.32, P = 0.67). Patients receiving anticoagulation were more likely than patients receiving aspirin to have had severe bleeding or a stroke by three months (3.9% v 1.7% (0.44, 0.20 to 0.97, P = 0.04)).

CONCLUSION

No evidence of a difference in the incidence of cardiac events was found between the two treatment groups, though the trial is too small to claim treatment equivalence confidently. A higher incidence of severe bleeding events and strokes was detected in the group receiving anticoagulation, suggesting that aspirin may be the drug of choice for most patients in this context.

Time as a factor in thrombolytic therapy

Animal studies first demonstrated the importance of early reperfusion in limiting the size of eventual infarction. This has been confirmed by human studies in which the early patency of the infarct-related artery is correlated with prognosis. Large randomised clinical trials suggested a graded effect, with a particularly great benefit if therapy was administered during the first hour after the onset of symptoms, and a progressive diminution in the effect thereafter, up to 12 h, and perhaps beyond. These studies did not, however, randomise patients to earlier or later treatment so the comparisons of different time intervals were not entirely valid. Five mortality trials have now randomised patients to early or later treatment and have demonstrated a significant benefit if more than 1 h is gained thereby. These trials were individually not large enough to establish the degree of gain from earlier treatment, but pooling their results suggests that gaining about 1 h will reduce mortality by about 17%.

Treatment for survivors of acute myocardial infarction: what have we learned from large intervention trials?

The current treatment of survivors of acute myocardial infarction is now largely based on sound scientific principles, supported by the results of large and well-designed clinical trials. These have demonstrated that aspirin, anticoagulants, beta-blockers, angiotensin converting enzyme inhibitors, and lipid-lowering agents reduce mortality and reinfarction in selected groups of patients. It remains uncertain whether these different treatments are additive and whether there are beneficial or undesirable interactions. In addition to informing us about the effectiveness or otherwise of these and other drugs, we have learned much about the conduct, analysis, and limitations of clinical trials in this context. The selection of patients for the various treatments is a matter of opinion because the results of the trials are open to a variety of interpretations. In assessing trials, one must be sure that they have been conducted on the intention to treat principle and that surrogate and composite end points have not been inappropriately used. In applying the results of trials to one's own practice, one must take into account the problems of extrapolation and subgroup analysis.

Secondary prophylaxis after myocardial infarction

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Guidelines for the early management of patients with myocardial infarction. British Heart Foundation Working Group

In light of recent publications relating to resuscitation and pre-hospital treatment of patients suffering acute myocardial infarction of British Heart Foundation convened a working group to prepare guidelines outlining the responsibilities of general practitioners, ambulance services, and admitting hospitals. The guidelines emphasise the importance of the rapid provision of basic and advanced life support; adequate analgesia; accurate diagnosis; and, when indicted, thrombolytic treatment. The working group developed a standard whereby patients with acute myocardial infarction should receive thrombolysis, when appropriate, within 90 minutes of alerting the medical or ambulance service--the call to needle time. Depending on local circumstances, achieving this standard may involve direct admissions to coronary care units, "fast track" assessments in emergency departments, or pre-hospital thrombolytic treatment started by properly equipped and trained general practitioners.

Time as a factor in thrombolytic therapy

There is abundant evidence from angiographic studies that reperfusion and/or patency rates are greater when thrombolysis is initiated earlier. Evidence of a reduction in infarct size has been provided by a number of studies, which have also suggested that earlier therapy preserves left ventricular function. The major intravenous thrombolytic mortality trials appear to confirm the importance of delivering therapy soon after the onset of symptoms e.g. GISSI and ISIS-2. However, the benefit reported in the first hour in GISSI may be questioned. Furthermore, it seems probable that those coming in late to trials are patients who did not have a sudden onset of symptoms, but whose symptoms persisted, perhaps with recurrent pain, or with heart failure symptoms. This may account for the fact that the benefit seen relatively late, particularly in ISIS-2, does not seem to accord with reperfusion, infarct size and LVEF findings. The true benefits of earlier therapy will be established only when patients are randomized to active therapy or placebo at one point in time and then switched to alternative therapy at a specified later time. This has been done in a small trial with alteplase in Belfast. The findings were suggestive but not conclusive of an improvement in LVEF in those treated earlier. The European Myocardial Infarction Project (EMIP) should go far towards answering the question. In most European cities the time between onset of symptoms and the initiation of skilled treatment for myocardial infarction is of the order of 5-6 h.(ABSTRACT TRUNCATED AT 250 WORDS)

The APSAC interventional mortality study (AIMS) trial: mortality data

The anistreplase (anisoylated plasminogen streptokinase activator complex or APSAC) intervention mortality study was designed as a double-blind, placebo-controlled study to test the effectiveness of anistreplase, 30 U administered intravenously within the first 6 hours of acute myocardial infarction. The primary endpoint of the study was mortality of all causes at 30 days and 1 year. Within 30 days, there were 77 deaths with placebo (17.8%) and 40 deaths (6.5%) with anistreplase, an odds reduction of 50.5% (p = 0.0006). By the end of one year, there had been a total of 113 deaths (17.8%) with placebo and 69 deaths (11.1%) with anistreplase, an odds reduction of 42.7% (p = 0.0007).

Increased survival after APSAC: 30-day and 12-month mortality data from the APSAC Intervention Mortality Study

Preliminary analysis of mortality data from the anisoylated plasminogen streptokinase activator complex (APSAC) Intervention Mortality Study (AIMS) showed a 47% reduction in 30-day mortality (with a 95% confidence interval of 21 to 65%) for patients treated with APSAC within 6 hours of onset of acute myocardial infarction. After follow-up of 1,004 patients for 30 days after randomization in the double-blind, placebo-controlled, clinical trial, researchers found that 61 patients (12.2%) in the placebo group had died compared with 32 patients (6.4%) in the APSAC group (p = 0.0016). Incomplete follow-up of these patients for 1 year provided an estimated mortality of 19.4% in the placebo group and 10.8% in the APSAC group (log-rank test for survival to year p = 0.0006). Benefit was seen irrespective of age, site of infarction and time from onset of symptoms up to 6 hours.

An analysis of factors predisposing to neurological injury in patients undergoing coronary bypass operations

In a prospective study of 312 patients undergoing elective coronary bypass surgery we evaluated 50 preoperative, intraoperative and postoperative factors with the aim of identifying predisposing causes for perioperative neurological morbidity. Factors which showed a significant association with the development of neurological complications included the duration and severity of heart disease before surgery; the presence of extracoronary vascular disease; history of cardiac failure; history of diabetes; difficulty in terminating bypass; intraoperative mean arterial pressure levels of less than 40 mmHg; a large drop in haemoglobin level during surgery; prolonged stay in the intensive therapy unit after operation; and abnormalities of blood pressure control in the postoperative period. The significance of these findings is discussed and a comparison made with data available from previous studies.

A controlled trial of GL enzyme in the treatment of acute myocardial infarction

GL enzyme (hyaglosidase) is a highly purified component enzyme of hyaluronidase. A therapeutic trial was carried out in the treatment of suspected myocardial infarction among 1,488 patients presenting within 6 h of the onset of symptoms. No significant reduction in mortality at 6 months was observed in the GL group (15.7%) compared with the placebo group (16.4%). Mortality at 2 weeks was also unaffected by treatment (GL 10.3%; placebo 10.9%).

Prevention of tolerance to nitroglycerin patches by overnight removal

This investigation assesses the extent of tolerance development with nitroglycerin patches and whether tolerance might be prevented by overnight patch removal. On commencing therapy, active patches significantly prolonged exercise time (3.5 hours after patch application) in comparison with placebo, with an accompanying reduction in ST-segment depression at maximal common workload. Patients then received continuous or 12-hour-daily intermittent patch therapy, in a double-blind fashion, for 7 days. Exercise testing was repeated before and after active patch application, on the eighth day of each treatment phase. During continuous therapy, beneficial effects on exercise time and ST depression were abolished. By contrast, during intermittent therapy, prolongation of exercise time and reduction in ST-segment depression still occurred, on testing 3.5 hours after active patch application. These results confirm previous studies showing a high degree of tolerance during continuous therapy with nitroglycerin patches and suggest that tolerance can be prevented by 12-hour-daily intermittent therapy.

Neurologic and neuropsychological morbidity following major surgery: comparison of coronary artery bypass and peripheral vascular surgery

As part of a prospective study of the neurologic and neuropsychological complications of coronary artery bypass graft surgery, 312 patients were compared with a control group of 50 patients undergoing major surgery for peripheral vascular disease. The purpose of comparing the 2 groups was to determine to what extent neurologic complications after heart surgery can be attributed to cardiopulmonary bypass. The 2 groups were similar with respect to age, preoperative neurologic and intellectual status, anesthetic methods, duration of operation, perioperative complications, and time spent in the intensive therapy unit. Certain potential risk factors for cerebrovascular disease were more common in the control than the coronary bypass patients. The important difference between the 2 groups was that only the latter group underwent cardiopulmonary bypass. In this group 191 of 312 (61%) and 235 of 298 (79%), respectively, developed early neurologic and neuropsychological complications. By the time of hospital discharge 17% had neurologic disability and 38% had significant neuropsychological symptoms. In the control group 9 of 50 (18%) developed neurologic complications resulting largely from trauma to lower limb sensory nerves. Two patients developed primitive reflexes. Fifteen of 48 (31%) showed neuropsychological impairment on 1 or 2 subtest scores. Moderate or severe intellectual dysfunction was not seen in the control patients in contrast to the 24% thus affected in the coronary bypass group. The difference in frequency and severity of central nervous system complications between the 2 groups is likely to reflect cerebral injury resulting from cardiopulmonary bypass.