Timing of coronary revascularization after acute myocardial infarction

Optimal Timing of Surgical Revascularization for Myocardial Infarction and Left Ventricular Dysfunction

Background:

The optimal timing of surgical revascularization for patients presenting with ST-segment elevation myocardial infarction (STEMI) and impaired left ventricular function is not well established. This study aimed to examine the timing of surgical revascularization after STEMI in patients with ischemic heart disease and left ventricular dysfunction (LVD) by comparing early and late results.

Methods:

From January 2003 to December 2013, there were 2276 patients undergoing isolated coronary artery bypass grafting (CABG) in our institution. Two hundred and sixty-four (223 male, 41 females) patients with a history of STEMI and LVD were divided into early revascularization (ER, <3 weeks), mid-term revascularization (MR, 3 weeks to 3 months), and late revascularization (LR, >3 months) groups according to the time interval from STEMI to CABG. Mortality and complication rates were compared among the groups by Fisher's exact test. Cox regression analyses were performed to examine the effect of the time interval of surgery on long-term survival.

Results:

No significant differences in 30-day mortality, long-term survival, freedom from all-cause death, and rehospitalization for heart failure existed among the groups (P > 0.05). More patients in the ER group (12.90%) had low cardiac output syndrome than those in the MR (2.89%) and LR (3.05%) groups (P = 0.035). The mean follow-up times were 46.72 ± 30.65, 48.70 ± 32.74, and 43.75 ± 32.43 months, respectively (P = 0.716). Cox regression analyses showed a severe preoperative condition (odds ratio = 7.13, 95% confidence interval 2.05–24.74, P = 0.002) rather than the time interval of CABG (P > 0.05) after myocardial infarction was a risk factor of long-term survival.

Conclusions:

Surgical revascularization for patients with STEMI and LVD can be performed at different times after STEMI with comparable operative mortality and long-term survival. However, ER (<3 weeks) has a higher incidence of postoperative low cardiac output syndrome. A severe preoperative condition rather than the time interval of CABG after STEMI is a risk factor of long-term survival.

Optimal timing of coronary artery bypass grafting in acute myocardial infarction

The timing of surgical coronary artery revascularization after an acute myocardial infarction is not well defined. The inherent difficulties of mobilizing a surgical team at odd hours has led to the adoption of a percutaneous coronary intervention strategy when possible or a clot-busting drug regimen when percutaneous coronary intervention is not available. Despite the difficulties and risks of surgical revascularization, there are situations where it may be indicated. We conducted a review of the literature to better understand the timing, scope, and risks of surgical coronary revascularization after an acute myocardial infarction.

Timing of bypass surgery in stable patients after acute myocardial infarction

OBJECTIVES

To determine the optimal timing for bypass surgery in stable patients after acute myocardial infarction (MI).

BACKGROUND

Coronary artery bypass graft surgery (CABG) is a proven treatment for coronary artery disease. Because of the hypothesized risk of hemorrhagic transformation, it had become common practice to wait four to six weeks after MI. Recently, improvements in surgical and perioperative management, as well as an increase in pre-CABG in-hospital waiting times and excess burden on health care resources, have pushed surgeons to operate earlier. The optimal timing for a stable patient to undergo CABG after MI is unclear, because there have been no randomized trials to answer this question.

METHODS

The published literature comparing early versus late surgical revascularization procedures in stable post-MI patients was reviewed.

RESULTS

No randomized, prospective trials were found; however, several retrospective studies were identified. Most series examining Q wave MIs showed that mortality is higher in the early stages post-MI and progressively decreases with time post-MI. When studies examined non-Q wave MIs separately, there appeared to be less of a mortality difference between early and late surgical revascularization. There was a large disparity between the definitions of early surgery post-MI among the studies, some as early as 6 h and others up to eight days. Factors that increased mortality include abnormal left ventricular function and urgency of surgery, and some studies found risk models helpful to define increased risk after infarction. The possible increased risk of early surgery may be balanced against the potential for improved remodelling, improved quality of life and decreased hospital stay costs.

CONCLUSIONS

There is a need for a randomized, prospective trial examining the optimal timing for CABG in stable post-MI patients.

Timing of coronary artery bypass graft surgery following acute myocardial infarction: a critical literature review

Despite more than 30 years' experience with coronary artery bypass surgery, controversy still exists about the optimal timing of surgical revascularization following acute myocardial infarction. To review the published information on this topic, a Medline search of the literature published between 1984 and October 2000 was performed. After reviews and individual case reports we re excluded, 11 retrospective and prospective studies remained for analysis. Pervasive heterogeneity with respect to inclusion criteria, outcome measurement, definitions, variance among studies of measured time between myocardial infarction (MI) and coronary artery bypass graft (CABG), differences in study endpoints, and evolution of surgical techniques and medical regimens over this time precluded formal meta-analysis. Although prospective randomized trials are lacking, the preponderance of data from the 11 retrospective and prospective observational studies suggests that timing of bypass surgery after infarction is not an independent predictor of outcome and that delaying coronary bypass surgery for an arbitrary period of time following acute MI is unwarranted. Rather, ventricular function, post-infarction ischemia, noncardiac comorbid conditions, and the urgency of the surgery itself constitute the important predictors of perioperative mortality, and these clinical factors should be used to estimate perioperative risk and decide upon the risk:benefit relationship for CABG in this patient population.

Urgent off-pump coronary artery bypass grafting

OBJECTIVES

The use of off-pump coronary artery bypass grafting (CABG) has become widespread, since it has proven less invasive and to promote early recovery. In this study, we investigated the efficacy of off-pump CABG in patients in the evolving phase of acute myocardial infarction.

METHODS

Retrospective chart review was carried out for patients undergoing urgent isolated off-pump and on-pump CABG at Shin-Tokyo Hospital Group between January 1991 and June 2001. The patients' demographic, operative data, and postoperative results were collected.

RESULTS

The off-pump group consisted of 19 males and 11 females with a mean age of 72.0 years and the on-pump group of 91 males and 38 females with a mean age of 64.3 years. Preoperative use of intraaortic balloon pumping and preoperative shock was more frequently observed in the on-pump group. The mean number of distal anastomoses was 3.1 +/- 0.9 in the off-pump group and 3.2 +/- 1.1 in the on-pump group (p = NS). Intubation time (18.5 vs 32.9 hours), ICU stay (3.4 vs 4.9 days), and postoperative stay (13.5 vs 24.3 days) were significantly shorter in the off-pump group than in the on-pump group (P < 0.05). The frequency of the major complications was significantly lower in the off-pump group (9/30, 30%) than the on-pump group (65/129, 50.4%), especially for postoperative low output syndrome (p < 0.05). Multivariate analysis demonstrated a significant reduction in the recovery period by use of off-pump CABG. Early follow-up results were similar between the two groups, in terms of late cardiac events and survival.

CONCLUSION

Urgent off-pump CABG is safe and provides early recovery, provided that the patient's intraoperative hemodynamics are taken into account.

Emergency myocardial revascularization for acute myocardial infarction: survival benefits of avoiding cardiopulmonary bypass

OBJECTIVE

Emergency coronary artery bypass grafting (CABG) for acute myocardial infarction (AMI) is associated with increased operative mortality. It has been suggested that this mortality might be reduced by performing the operation without cardiopulmonary bypass (CPB).

METHODS

Between January 1992 and April 1998, 77 patients underwent emergency CABG within 48 h of AMI. Thirty seven were operated on with CPB, and 40 without CPB. The two groups were similar regarding age, gender, left-ventricular ejection fraction (EF) and preoperative use of intra-aortic balloon pump (IABP; 50%). The mean number of grafts/patient was 3 in the CPB group, and 1.9 in the No-CPB group (P<0.0001).

RESULTS

Operative mortality in the CPB group was 24% (nine of 37) compared to 5% (two of 40) without CPB (P=0.015). Follow-up ranged between 6 and 66 months. There were no late deaths in the CPB group compared to nine (22%) in the No-CPB group (P<0.0066). Patients operated on with CPB had lower rates of recurrent angina (0 versus 15%; P=0.04) and re-interventions (0 versus 15%; P=0.04).

CONCLUSIONS

Our experience suggests that CABG without CPB is the preferred method of myocardial revascularization, due to the fact that it carries lower mortality than CABG with CPB. The trade-off includes increased rates of recurrent angina, re-interventions and late mortality.

Surgical management of unstable patients in the evolving phase of acute myocardial infarction

BACKGROUND

Acute myocardial infarction (AMI) can be treated with thrombolysis or coronary catheter intervention; surgical treatment--coronary artery bypass grafting (CABG)--is reserved for the patients in whom other procedures have failed. We performed CABG in 47 patients during the evolving phase of AMI, and analyzed their short-term and long-term results.

METHODS

Preoperative, intraoperative, and postoperative data were analyzed in patients who underwent emergency CABGs for AMI between January 1, 1992, and July 31, 1998. CABGs performed more than 7 days after AMI were excluded from this study.

RESULTS

The subjects were 47 patients (33 males and 14 females) with AMI who were treated by emergency CABG. Intraaortic balloon pumping was used in 44 cases and percutaneous circulatory pulmonary support was used in 3 cases. The mean interval between the onset of AMI and surgery was 27.4 +/- 27.9 hours. The mean number of bypass grafts was 3.0 +/- 1.1, and at least 1 arterial conduit was used in 45 cases (95.7%). Aortic clamp time, pump time, and operative time were 64.7 +/- 31.7, 117.3 +/- 55.2, and 313.2 +/- 84.8 minutes, respectively. IABP or percutaneous cardiopulmonary support were removed in the intensive care unit (ICU) 30.0 +/- 28.9 hours after CABG. The patients were extubated 41.4 +/- 40.5 hours after surgery, remained in ICU for 4.7 +/- 2.7 days, and were discharged from the hospital after 27.0 +/- 22.5 days. Three patients died from multiorgan failure related to postoperative sepsis, and 8 cases of major complications were observed. The actuarial 5-year survival rate of the patients treated with CABG was 83.0%.

CONCLUSIONS

Surgical treatment in the unstable patients after AMI can be performed with acceptable risk. Arterial revascularization may contribute to improvement in long-term results.

[The practical clinical guidelines of the Sociedad Española de Cardiología on coronary surgery]

Surgery in coronary disease, including myocardial revascularization and the surgery of mechanical complications of acute myocardial infarction, has shown to improve the symptoms, quality of life and/or prognosis in certain groups of patients. The expected benefit in each patient depend on many well-known factors among which the appropriateness of the indication for surgery is fundamental. The objective of these guidelines is to review current indications for cardiac surgery in patients with coronary heart disease through an evaluation of the degree of evidence of effectiveness in the light of current knowledge (systematic review of bibliography) and expert opinion gathered from various reports. Indications and the degree of recommendation for conventional coronary artery bypass grafting have been established for each of the most frequent anatomo-clinical situations defined by clinical symptoms (stable angina, unstable angina and acute myocardial infarction) as well as by left ventricular function and extend of coronary disease. Furthermore, the subgroups with the greatest surgical risk and stratification models are described to aid the decision making process. Also we analyse the rational basis and indication for the new surgical techniques such as minimally invasive coronary surgery and total arterial revascularization. Finally, the indication and timing of surgery in patients with mechanical complications of acute myocardial infarction are considered.

Coronary artery bypass without cardiopulmonary bypass for patients with acute myocardial infarction

OBJECTIVE

Between January 1992 and December 1994, 57 patients having an acute myocardial infarction with coronary anatomy suitable for coronary artery bypass grafting without cardiopulmonary bypass underwent this procedure within 1 week of the infarction. We describe the surgical results of these high-risk patients.

METHODS

The study population included 43 male patients (75%) and 14 female patients (25%) whose mean age was 58.5 +/- 10.4 years. Thirty-two patients (56%) underwent emergency bypass grafting within 48 hours of an acute myocardial infarction, 4 of them (12.5%) as a bailout procedure after complicated percutaneous transluminal coronary angioplasty. Of these 32 patients, 7 patients (22%) were in cardiogenic shock, and 10 patients (31%) required preoperative intra-aortic balloon pump. Twenty-five patients (44%) underwent coronary bypass grafting 2 to 7 days after an acute myocardial infarction. The mean number of grafts per patient was 1.8 (range, 1-4), and the internal thoracic artery was used in 47 patients (82%). Only 7 patients (12%) received grafts to a circumflex marginal branch.

RESULTS

Operative mortality was 1.7% (1 patient), and the mean postoperative hospital stay was 6.8 +/- 3 days. One- and 5-year actuarial survivals were 94.7% and 82.3%, respectively. Angina returned in 7 patients (12%), 1 of whom underwent reoperation. Multivariate analysis revealed renal failure and preoperative cardiogenic shock to be independent predictors of overall mortality. Old myocardial infarction and operation within the first 48 hours were independent predictors of overall unfavorable outcome events.

CONCLUSIONS

These results suggest that coronary artery bypass grafting without cardiopulmonary bypass is a relatively low-risk procedure for patients having an infarction with coronary anatomy suitable for this technique.

Myocardial revascularisation after acute myocardial infarction

One hundred and twenty-three patients had coronary artery bypass grafting (CABG) within 30 days of acute myocardial infarction (AMI) from May 1992 to November 1997. Commonest infarct was anterior transmural (61.8%) and commonest indication of surgery was post-infarct persistent or recurrent angina (69.1%). Ten patients were operated within 48 h and 36 between 48 h to 2 weeks of having MI. Out of these, nine patients were having infarct extension and cardiogenic shock at the time of surgery. Pre-operatively fourteen patients were on inotropes of which six also had intra-aortic balloon pump (IABP) support. All patients had complete revascularisation with 3.8+/-1.2 distal anastomoses per patient. By multivariate analysis, we found that independent predictors of post-operative morbidity [inotropes >48 h, use of IABP, ventilation >24 h, ICU stay >5 days] and complications [re-exploration, arrhythmias, pulmonary complications, wound infection, cerebrovascular accident (CVA)] were left ventricular ejection fraction (LVEF) <30%, Q-wave MI, surgery <48 h after AMI, presence of pre-operative cardiogenic shock and age >60 years (P < or = 0.01). Mortality at 30 days was 3.3%. LVEF <30%, Q-wave MI, surgery <48 h after AMI, presence of pre-operative cardiogenic shock and age >60 years were found to be independent predictors of 30 days mortality (P < or = 0.01). Ninety patients were followed up for a mean duration of 33 months (1 to 65 months). There were three late deaths and five patients developed recurrence of angina. To conclude, CABG can be carried out with low risk following AMI in stable patients for post-infarct angina. Patients who undergo urgent or emergent surgery and who have pre-operative cardiogenic shock, IABP, poor left ventricular functions, age >60 years and Q-wave MI are at increased risk.

Appropriate timing of elective coronary artery bypass graft surgery following acute myocardial infarction

BACKGROUND

The appropriate timing of elective coronary artery bypass surgery (CABG) following acute myocardial infarction (AMI) remains uncertain. It is hypothesized that a waiting period allows the myocardium to recover prior to revascularization, thus decreasing morbidity and mortality. This study was designed to determine if a waiting strategy is justified following AMI in patients requiring elective CABG.

METHODS

Between 1994 and 1996, 214 patients underwent isolated, nonrepeat, elective CABG. Three groups were evaluated: group I, control, 155 patients with no AMI; group 11, 39 patients with nontransmural AMI; and Group III, 20 patients with transmural AMI. Demographics, intraoperative, and postoperative variables were collected and compared among all groups.

RESULTS

Groups were well-matched demographically: group I, patients waited an average of 2.3 days in hospital prior to operation; group II, an average of 4.2 days; and group III, an average of 5.2 days. Except for the use of inotropes, group I 34%, group 11 39%, and group III 70% (P = 0.007), and the intra-aortic balloon pump, group I 0%, group 11 8%, and group III 25% (P = 0.001). There were no differences in complications. Importantly, there was no difference in mortality or postoperative length of stay. The mortality in group I was 2.6%, in group 11 2.6%, and in group III 0%. The length of stay in groups I and II was 8.5 days, and in group III, 8.1 days.

CONCLUSION

A waiting period of 3 to 5 days after a nontransmural AMI and 5 to 7 days after a transmural AMI can produce similar postoperative results to non-AMI patients undergoing CABG. Thus, a waiting strategy to allow the myocardium to recover is justified.

Coronary artery bypass grafting within 30 days of an acute myocardial infarction

Risks and benefits of performing coronary artery bypass grafting (CABG) within 30 days of an acute myocardial infarction (AMI) were examined. In 642 patients operated on between January 1988 and December 1993, emergent CABG was performed in 46 patients for cardiogenic shock mainly for failed thrombolysis in patients with an evolving AMI. The remaining patients underwent urgent (< 72 hours) or elective (> 72 hours) revascularization for failed percutaneous transluminal coronary angioplasty (n = 73), postinfarction angina (n = 381), vein graft stenosis (n = 100), and complications after an AMI (n = 42). In patients who underwent primary CABG for an uncomplicated AMI, the infarct was subendocardial in 68, anterolateral or septal in 200, inferior or posteroinferior in 200, and posterolateral in 32 patients. Early mortality (< 30 days) was 5.9% for the entire series and 0%, 4.5%, 4.5%, 29%, 9%, 8%, 10%, and 26% for the subsets of patients with subendocardial infarct, anterolateral or septal infarct, inferior or posteroinferior infarct, ischemic mitral regurgitation, left ventricular aneurysm, redo CABG, age more than 70 years, and left ventricular ejection fraction less than 0.30, respectively. By multivariate analysis, independent predictors of early mortality were left ventricular ejection fraction less than 0.30, age more than 70 years, and cardiogenic shock.(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary artery bypass graft surgery after thrombolytic therapy in the Thrombolysis in Myocardial Infarction Trial, Phase II (TIMI II)

OBJECTIVES

We examined the results of coronary artery bypass graft surgery after thrombolytic therapy in the Thrombolysis in Myocardial Infarction trial, Phase II (TIMI II) with particular emphasis on patient characteristics, the impact of antecedent percutaneous transluminal coronary angioplasty and morbidity and mortality in certain subgroups.

BACKGROUND

Coronary bypass surgery is frequently used after thrombolytic therapy, but there is relatively little information with regard to early and late outcomes.

METHODS

We analyzed 3,339 patients enrolled in the TIMI II trial. Bypass surgery was performed in 390 patients (11.7%): 54 (14%) within 24 h after entry into the trial or within 24 h of coronary angioplasty and 336 (86%) between 24 h and 42 days after entry.

RESULTS

Perioperative mortality rates were, respectively, 16.7% and 3.9% (p < 0.001); perioperative myocardial infarction rates were 5.6% and 6.2%, respectively; and major hemorrhagic events occurred in 74% and 50.9%, respectively (p = 0.002). On multivariate analysis, the only independent predictor of perioperative mortality was bypass surgery within 24 h after entry or after coronary angioplasty. Among patients undergoing bypass surgery within 24 h of entry or after coronary angioplasty, the prevalence of multivessel disease (59.1% vs. 77.8%) and use of the internal thoracic artery (18.5% vs. 62.5%) were lower than in the remaining surgical patients. Among the 322 perioperative survivors, the 1-year mortality rate after discharge was only 2.2% and 1.9%, respectively, in the two groups. Only one patient had a documented recurrent myocardial infarction during the first year.

CONCLUSIONS

The increased mortality rate with bypass surgery after thrombolytic therapy, particularly in patients undergoing operation within 24 h of coronary angioplasty or during the involving phase of infarction, must be balanced against the excellent 1-year prognosis and perioperative survivors, who are in general a group at higher risk of death or recurrent infarction. These data provide a basis for comparison for future studies.

Recent preoperative myocardial infarction increases the risk of surgery for unstable angina

Patients with postinfarction angina undergoing surgery for unstable angina face an increased risk of operative mortality. Between January 1982 and December 1987, clinical, angiographic, and operative data was collected prospectively in 588 unstable patients with a prior myocardial infarction within 30 days of surgery (MI) and 5951 unstable patients without preoperative damage (NONMI). MI patients were characterized as being older (age greater than or equal to 70 years: MI, 19.7%; NONMI, 11.6%; p less than 0.001) and having more left ventricular dysfunction (left ventricular ejection fraction less than 40%: MI, 34.8%; NONMI, 26.4%; p less than 0.001). Semi-elective surgery was performed in 82.0% of NONMI patients while 76.9% of MI patients underwent urgent surgery. Operative mortality was increased in MI patients (MI, 11.1%; NONMI, 4.0%; p less than 0.001) which was related to the extent of preoperative MI (non-Q wave, 8.3%; Q wave, 17.5%; p less than 0.001). Stepwise logistic regression analysis identified preoperative MI as an independent risk variable of operative mortality for unstable angina. Separate multivariate analyses were performed to identify the independent predictors for MI and NONMI patients. The multivariate predictors of operative death for MI patients were left ventricular dysfunction, reoperative coronary surgery, nonuse of the internal mammary, age, transmural MI (relative risk 2.11 vs non-Q wave infarction) and left main stenosis. For NONMI patients, the independent variables were urgent operation, left ventricular dysfunction, reoperation, female gender, left main stenosis, and age. The results of this study indicate that recent preoperative MI adversely influences the surgical results in patients with unstable angina. Alternative treatment strategies are warranted for high risk patients, particularly those with transmural MIs and impaired ventricular function.

True emergency coronary artery bypass surgery

Previous reports of emergency coronary artery bypass grafting often included cases that were not true surgical emergencies, thereby creating inappropriately favorable results. To accurately investigate this important subgroup of patients, we analyzed our recent experience with truly emergent coronary artery bypass grafting. From January 1984 to January 1989, 117 patients underwent true emergency bypass grafting for acute refractory coronary artery ischemia. Clinical deterioration was associated with failure of percutaneous angioplasty in 37 patients and instability during diagnostic catheterization in 13 patients. Refractory ischemia developed in the remaining patients while on the ward or in the intensive care unit. All operations were performed within four hours of surgical consultation, most within one hour. Overall in-hospital operative mortality was 14.5% (17/117), and 76.5% of deaths (13/17) were due to cardiac-related causes. Major morbidity occurred in 35.9% (42/117). Univariate analysis isolated ejection fraction, extent of coronary artery disease, previous myocardial infarction, hypertension, need for inotropic support, use of an intraaortic balloon pump, and cardiopulmonary resuscitation as risk factors for operative mortality. Stepwise multivariate analysis confirmed that previous myocardial infarction, hypertension, cardiopulmonary resuscitation, and reoperation were independently significant risk factors. Age, sex, diabetes, left main disease, and peripheral vascular disease had no significant impact on the prognosis. The 4% operative mortality (2/50) for patients taken directly to the operating room from the catheterization suite was significantly lower than the 22.4% mortality (15/67) associated with emergencies arising on the ward or intensive care unit (p less than 0.01). A logistic risk equation developed from this population accurately modeled operative mortality.(ABSTRACT TRUNCATED AT 250 WORDS)

Long-term survival after postinfarction bypass operation: early versus late operation

A study of 832 patients operated on within 30 days of infarction from 1974 to 1987 has resulted in 2,388 patient-years (maximum, 14 years) of prospectively acquired follow-up. This study excludes 74 patients in whom cardiogenic shock was the indication for operation. Five-year survival (+/- standard error) was 84% +/- 2%, 85% +/- 1%, and 90% +/- 1%, and 10-year survival was 71% +/- 4%, 68% +/- 1%, and 78% +/- 1% for patients with acute infarction, remote infarction, and no previous infarction, respectively. Age and left ventricular end-diastolic pressure significantly affected long-term survival for patients with acute infarction by both univariate and multivariate analysis. For patients aged less than 65 years, the 5-year and 10-year actuarial survival rates were 89% +/- 2% and 80% +/- 4%, compared with 75% +/- 3% and 58% +/- 9%, respectively, for patients aged more than 65 years. The survival percentages were 89% +/- 2% and 75% +/- 6% for patients with left ventricular end-diastolic pressure less than 15 mm Hg compared with 77% +/- 5% and 67% +/- 7% for patients with left ventricular end-diastolic pressure greater than 15 mm Hg. Operative mortality was 7.6% for patients operated on within 24 hours, compared with 4.1% for patients operated on between 2 and 30 days after infarction. Ten-year survival was similar (about 70%) for all timing groups. Based on these long-term results, there appears to be little to gain by delaying coronary artery bypass grafting, when indicated, after infarction occurs.

Postinfarction angina

In conclusion, the PIA patient is at high risk, with higher early as well as late mortality. The pathophysiology of PIA is complex and may vary from patient to patient. The concepts of ischemia at a distance and ischemia in the infarct zone have led to a better understanding of early PIA. Coronary spasm may play an important role in most PIA patients as in the general population of patients with angina pectoris. Medical therapy is efficacious in many, although it may on rare occasion aggravate myocardial ischemia. Urgent coronary arteriography is generally safe and should be performed as soon as possible for medically refractory PIA. CABG appears to be safe in experienced hands, but its timing must be individualized. The IABP should be reserved for more unstable patients for fear of vascular complications. Randomized controlled trials such as the BARI Trial will further compare PTCA with CABG.

Early myocardial revascularization for postinfarction angina

In 1983 and 1984, coronary artery bypass grafting (CABG) was performed on 107 consecutive patients for postinfarction angina. In each instance, CABG was done within 30 days of infarction. Sixty-three patients (59%) required intravenous administration of nitroglycerin and/or the intraaortic balloon pump (IABP) for relief of angina. Oral medications relieved angina in the remaining 44 patients. Thirty-eight patients underwent CABG 7 days or less after the infarction (Group 1), 25 received it between 8 and 15 days later (Group 2), and 44 had CABG between 16 and 30 days later (Group 3). There were 9 in-hospital deaths: 4 in Group 1, 2 in Group 2, and 3 in Group 3. Thirteen patients needed the IABP for hemodynamic stability as well as relief of angina. Even when the patient was stable hemodynamically, death was more likely to occur among these 13 patients if CABG was conducted within 7 days of infarction. Follow-up was 94% complete at 29.4 months. Eighty-six percent of patients were asymptomatic or in New York Heart Association Functional Class I, and 6% were in Class II. There were 2 late deaths. CABG for angina can be accomplished within 30 days of an acute infarction with good results. The exception to this rule is the patient in whom shock develops after a myocardial infarction and who, despite stabilization, receives CABG within 7 days of the infarction.

Determinants of cardiac failure after coronary bypass surgery within 30 days of acute myocardial infarction

Timing of coronary artery bypass grafting after acute myocardial infarction (MI) is controversial, especially if myocardial function is depressed. Early coronary artery bypass grafting may result in reperfusion injury causing cardiac failure. Delay, however, may risk a second ischemic event. This study was performed to determine if four preoperative factors--time after MI, ejection fraction, ischemia (need for intravenous administration of nitroglycerin), and failure (need for inotropic support)--independently predict postoperative cardiac failure. Postoperative failure was defined as the need for inotropic support or intraaortic balloon pumping. The study group consisted of 145 patients who underwent isolated coronary artery bypass grafting between January, 1980, and July, 1985, within 4 weeks of an acute MI. Postoperatively 38 patients (26%) had cardiac failure. Five patients, all of whom had postoperative cardiac failure, died. Univariate and stepwise logistic regression analyses showed preoperative failure (p = .0001), ejection fraction less than 45% (p = .002), and preoperative ischemia (p = .02) were predictors of postoperative cardiac failure. Time after MI was not found to be an independent predictor (p = .96). We conclude that if ischemia or threatening coronary anatomy is present early after MI and clinical improvement is not occurring, operative intervention should be strongly considered at that time, as it does not appear that delay itself reduces the risk of cardiac failure and may risk a second ischemic event.

Predictors of outcome in early revascularization after acute myocardial infarction

We have reviewed 44 consecutive patients undergoing myocardial revascularization from 1 to 42 days after myocardial infarction. Operation within 12 days of transmural myocardial infarction carried a substantially high risk, particularly in patients with poor ventricular function. Patients with subendocardial infarction may be safely operated on shortly after infarction has occurred. In those with transmural infarcts, it may be advantageous to delay operation if early and aggressive medical therapy can effectively control the symptoms. This has to be counterbalanced, however, by the realization that the situation should not be allowed to slide into one of irreparable ventricular damage from infarct extension.