Reperfusion protocol and results in 738 patients with evolving myocardial infarction

Survival of patients treated with intra-aortic balloon counterpulsation for cardiogenic shock in a tertiary centre: variables correlated with death

OBJECTIVE

To describe the characteristics and mortality rates of 132 cardiogenic shock patients treated with intra-aortic balloon counterpulsation at a university hospital.

INTERVENTIONS

All patients underwent intra-aortic balloon counterpulsation. A total of 99 out of 132 patients were revascularized with angioplasty, surgery or were transplanted (intervention group), 33 out of 132 had no further intervention (no-intervention group).

MEASUREMENTS AND RESULTS

Overall mortality was 54.5% (72/132). In the intervention group mortality was 50.5% (50/99), in the no-intervention group mortality was 66.6% (22/33). The odds ratio for death comparing the intervention group with the no-intervention group was 0.533 (95% confidence interval 0.238-1.189, P = 0.122). By univariate analysis, diabetes and a left ventricular ejection fraction of less than 0.35 represented an increased odds ratio of death of 4.25 (1.813-9.965, P = 0.001) and 3.03 (1.22-7.54, P = 0.015), respectively. A lactate level greater than 2.5 mg/dl at baseline resulted in an increased odds ratio of death of 5.185 (1.988-13.525, P = 0.0001). Using a multivariate logistic regression analysis, a left ventricular ejection fraction less than 0.35 and diabetes remained significantly correlated with death.

CONCLUSION

Mortality rates remain high in cardiogenic shock patients in need of intra-aortic balloon counterpulsation. The odds ratio for death tended to be lower in the intervention group compared with the no-intervention group, although the absolute difference in mortality as a result of an intervention was only 15.2%, and did not reach statistical significance probably because of the small sample size. Diabetes and an ejection fraction lower than 35% are significant predictors for a worse prognosis.

[Elective primary angioplasty in cardiogenic shock: results from a single center]

INTRODUCTION

Cardiogenic shock is the leading cause of death among patients hospitalized for acute myocardial infarction. Conventional treatment for acute myocardial infarction does not achieve a better outcome in these patients, but prior studies with emergency revascularization by coronary angioplasty seem to provide encouraging results.

PATIENTS AND METHOD

A retrospective study of the clinical and angiographic results of elective primary angioplasty in 48 patients with cardiogenic shock complicating acute myocardial infarction of less than 12 hours is described. Intraaortic balloon counterpulsation was used in 79% of the patients. Patients with cardiogenic shock secondary to mechanical complications were excluded.

RESULTS

Angiographic success, defined as a residual stenosis < 50% and final TIMI flow >/= 2, was achieved in 85% of the culprit lesions, and stents were implanted in 76%. Multivessel angioplasty was performed in 25% of the patients, and abciximab was used in 35% of the cases. Mean time from the onset of symptoms to angioplasty was 7.4 +/- 3.1 hours. In-hospital survival was 58%, and was 54% at six months follow-up.

CONCLUSIONS

Emergency coronary revascularization with primary angioplasty and intracoronary stenting is effective in patients with acute myocardial infarction and cardiogenic shock. TIMI flow >/= 2 is achieved in most patients, and mortality is reduced when compared with conservative treatment in historical series.

Impact of thrombolysis, intra-aortic balloon pump counterpulsation, and their combination in cardiogenic shock complicating acute myocardial infarction: a report from the SHOCK Trial Registry. SHould we emergently revascularize Occluded Coronaries for cardiogenic shocK?

OBJECTIVES

We sought to investigate the potential benefit of thrombolytic therapy (TT) and intra-aortic balloon pump counterpulsation (IABP) on in-hospital mortality rates of patients enrolled in a prospective, multi-center Registry of acute myocardial infarction (MI) complicated by cardiogenic shock (CS).

BACKGROUND

Retrospective studies suggest that patients suffering from CS due to MI have lower in-hospital mortality rates when IABP support is added to TT. This hypothesis has not heretofore been examined prospectively in a study devoted to CS.

METHODS

Of 1,190 patients enrolled at 36 participating centers, 884 patients had CS due to predominant left ventricular (LV) failure. Excluding 26 patients with IABP placed prior to shock onset and 2 patients with incomplete data, 856 patients were evaluated regarding TT and IABP utilization. Treatments, selected by local physicians, fell into four categories: no TT, no IABP (33%; n = 285); IABP only (33%; n = 279); TT only (15%; n = 132); and TT and IABP (19%; n = 160).

RESULTS

Patients in CS treated with TT had a lower in-hospital mortality than those who did not receive TT (54% vs. 64%, p = 0.005), and those selected for IABP had a lower in-hospital mortality than those who did not receive IABP (50% vs. 72%, p < 0.0001). Furthermore, there was a significant difference in in-hospital mortality among the four treatment groups: TT + IABP (47%), IABP only (52%), TT only (63%), no TT, no IABP (77%) (p < 0.0001). Patients receiving early IABP (< or = 6 h after thrombolytic therapy, n = 72) had in-hospital mortality similar to those with late IABP (53% vs. 41%, n = 64, respectively, p = 0.172). Revascularization rates differed among the four groups: no TT, no IABP (18%); IABP only (70%); TT only (20%); TT and IABP (68%, p < 0.0001); this influenced in-hospital mortality significantly (39% with revascularization vs. 78% without revascularization, p < 0.0001).

CONCLUSIONS

Treatment of patients in cardiogenic shock due to predominant LV failure with TT, IABP and revascularization by PTCA/CABG was associated with lower in-hospital mortality rates than standard medical therapy in this Registry. For hospitals without revascularization capability, a strategy of early TT and IABP followed by immediate transfer for PTCA or CABG may be appropriate. However, selection bias is evident and further investigation is required.

Cardiogenic shock complicating acute myocardial infarction--etiologies, management and outcome: a report from the SHOCK Trial Registry. SHould we emergently revascularize Occluded Coronaries for cardiogenic shocK?

OBJECTIVES

This SHOCK Study report seeks to provide an overview of patients with cardiogenic shock (CS) complicating acute myocardial infarction (MI) and the outcome with various treatments. The outcome of patients undergoing revascularization in the SHOCK Trial Registry and SHOCK Trial are compared.

BACKGROUND

Cardiogenic shock is the leading cause of death in patients hospitalized for acute MI. The randomized SHOCK Trial reported improved six-month survival with early revascularization.

METHODS

Patients with CS complicating acute MI who were not enrolled in the concurrent randomized trial were registered. Patient characteristics were recorded as were procedures and vital status at hospital discharge.

RESULTS

Between April 1993 and August 1997, 1,190 patients with CS were registered and 232 were randomized in the SHOCK Trial. Predominant left ventricular failure (78.5%) was most common, with isolated right ventricular shock in 2.8%, severe mitral regurgitation in 6.9%, ventricular septal rupture in 3.9% and tamponade in 1.4%. In-hospital Registry mortality was 60%, with ventricular septal rupture associated with a significantly higher mortality (87.3%) than all other categories (p < 0.01). The risk profile and mortality were lower for Registry patients who were managed with thrombolytic therapy and/or intra-aortic balloon counter-pulsation, coronary angiography, angioplasty and/or coronary artery bypass surgery. After adjusting for these differences, the extent to which survival was improved with early revascularization was similar to that observed in the randomized SHOCK Trial.

CONCLUSIONS

In this prospective Registry the etiology of CS was a mechanical complication in 12%. The similarity of the beneficial treatment effect in patients undergoing early revascularization in the SHOCK Trial Registry and SHOCK Trial provides strong support for the generalizability of the SHOCK Trial results.

SHould we emergently revascularize Occluded Coronaries for cardiogenic shocK: an international randomized trial of emergency PTCA/CABG-trial design. The SHOCK Trial Study Group

BACKGROUND

Cardiogenic shock (CS) is the leading cause of death in patients hospitalized with acute myocardial infarction (MI). Nonrandomized studies suggest reduced mortality rate with revascularization.

TRIAL DESIGN

The SHOCK trial is a multicenter, randomized, and unblinded study with a Registry for trial-eligible and ineligible nonrandomized patients. The trial is testing the hypothesis that a direct invasive strategy of emergency revascularization for patients with cardiogenic shock complicating acute MI will reduce 30-day all-cause mortality rate by 20 absolute percentage points compared with initial medical stabilization. Eligibility criteria include development of CS within 36 hours of an acute transmural MI as evidenced by ST elevation or new left bundle branch block MI; clinical criteria for CS with hemodynamic confirmation; absence of a mechanical, iatrogenic, or other cause of shock; and enrollment within 12 hours of CS diagnosis. Patients randomly assigned to emergency revascularization immediately undergo coronary angiography, with percutaneous transluminal coronary angioplasty or coronary artery bypass grafting depending on the coronary anatomy. Patients assigned to initial medical stabilization may undergo revascularization >/=54 hours after randomization.

END POINTS

The primary end point is all-cause 30-day mortality after randomization. Secondary end points include death at trial termination, changes in left ventricular dimensions and function measured by echocardiography at randomization and 2 weeks later, and changes in quality of life and physical functioning from 2 weeks after discharge to 6 months after MI.

[Prognosis and management in patients with left main shock syndrome--emergency PTCA following CABG]

To clarify the optimal management and delineate the characteristics of patients with severe left main disease and cardiogenic shock as a result of an acute anterolateral myocardial infarction (left main shock syndrome), we analyzed the course of 13 such patients from September 1989 to June 1997. Of the 13 patients, 7 (53.8%) were managed with emergency coronary angioplasty (group A), 3 (23.1%) were treated with emergency coronary angioplsty following coronary bypass graft surgery (group B) and 3 (23.1%) underwent emergency coronary bypass graft surgery alone (group C). The interval from the beginning of myocardial ischemia to revascularization was 266 +/- 303 min. The degree of diameter stenosis found in the left main coronary artery was 98.1 +/- 1.8%. Overall in-hospital mortality for the 13 patient with left main shock syndrome was 76.9% (group A: 7/7; group B: 1/3; group C: 2/3, NS) and operative mortality was 61.5% (group A: 6/7; group B: 0/3; group C: 2/3, p = 0.03). When all 13 patients were examined together, the presence of ventricular tachycardia (VT) x ventricular fibrillation (Vf) was found to be the most powerful univariate predictor of operative death (p = 0.03). This is, 7 (87.5%) of the 8 patients with VT x Vf at presentation died within 30 postoperative days, and only 1 (20%) of the 5 patients without VT x Vf died (p = 0.03). Age, percent stenosis of the left main or right coronary arteries, the interval from the beginning of myocardial ischemia to revascularization, intubation, systolic pressure, fractional shortning, pulmonary artery pressure, pulmonary capillary wedge pressure, coronary risk factors, pulmonary edema, mitral regurgitation and percutaneous cardiopulmonary support failed to attain univariate significance at the P = .1 level. The postoperative peak CPK level was 15665 +/- 6710 IU/1 in operative death compared to 4733 +/- 2749 IU/1 in operative survival (p = 0.01). In conclusion, emergency coronary angioplasty following coronary bypass graft surgery for left main shock syndrome has been a very successful therapeutic option. Finally, for the entire group of 13 patients with left main shock syndrome, VT x Vf significantly decreased short-term survival.

Surgical revascularization for acute coronary insufficiency: analysis of risk factors for hospital mortality

BACKGROUND

A retrospective study of 444 patients undergoing urgent and emergent coronary artery bypass grafting for acute coronary insufficiency was performed to identify the risk factors for hospital death specifically associated with the clinical severity of the acute coronary insufficiency syndrome.

METHODS

The patients were divided into three groups-urgent, emergent A, and emergent B-on the basis of the evolution of the clinical pattern of the acute coronary insufficiency syndrome on full medical treatment. The three categories were defined as follows: urgent (257 patients), surgical revascularization could be delayed for 24 to 36 hours after surgical consultation because of adequate control of ischemia; emergent A (127 patients), prompt myocardial revascularization was required because medical treatment achieved only transient regression of an unrelenting ischemic pattern; and emergent B (60 patients), prompt myocardial revascularization was required because the acute coronary insufficiency was entirely refractory to medical treatment.

RESULTS

Mortality rates were 7.4% for the urgent group, 13.4% for the emergent A group, and 31.7% for the emergent B group. Multivariate analysis identified the following as risk factors for hospital mortality: ejection fraction (p = 0.023) and aortic cross-clamp time (p = 0.10) for the urgent group; aortic cross-clamp time (p = 0.017), ejection fraction (p = 0.03), and nonuse of blood cardioplegia (p = 0.04) for the emergent A group; and cardiogenic shock (p = 0.00), preoperative ischemic interval (p = 0.00), aortic cross-clamp time (p = 0.018), and nonuse of blood cardioplegia (p = 0.012) for the emergent B group.

CONCLUSIONS

A more exact definition of patient risk can be achieved when predictive outcome models are constructed using the risk factors specifically related to each level of clinical severity of the ischemic syndrome.

Surgical treatment for life-threatening acute myocardial infarction: a prospective protocol

OBJECTIVE

In this paper we describe the preliminary results of a prospective operative protocol designed in order to define the role of emergent myocardial revascularization in extensive acute myocardial infarction and in post-infarction cardiogenic shock.

METHODS

Entry criteria are: age < 75 years; anterior acute myocardial infarction with ST segment elevation > 4 leads, infero-postero-lateral or inferior and right ventricular within 6 h from onset of chest pain; post-infarction cardiogenic shock within 3 h from onset of shock. From November 1994 to July 1995, after emergency coronary arteriography, 23 patients were treated by coronary artery bypass grafting. Fifteen were operated for extensive acute myocardial infarction (group A, mean age 54.1 +/- 9.4 years) and eight for post-infarction cardiogenic shock (group B mean age 65.0 +/- 8.7 years). Mean time from onset was 4.4 +/- 1.3 h in group A and 2.2 +/- 0.8 h in group B. Mean left ventricular ejection fraction was 39.3 +/- 12.7% in group A and 22.6 +/- 3.5% in group B. Six out of eight group B patients needed intraaortic balloon counterpulsation preoperatively, and 2/8 cardiopulmonary resuscitation.

RESULTS

Myocardial revascularization consisted in 3.4 +/- 1.1 grafts in group A (vein grafts, except for 8 patients who also received a left internal thoracic artery graft) and 3.3 +/- 1.1 vein grafts in group B. All patients in group B and 3/15 (20%) in group A underwent intraaortic balloon counterpulsation. In-hospital death occurred in 1/15 (6.7%) patients of group A and in 4/8 (50%) patients of group B. At a mean follow-up of 4.1 +/- 3.4 months for group A and 3.9 +/- 2.2 months for group B left ventricular ejection fraction was 43.4 +/- 9.0% in group A and 35.7 +/- 13.1% in group B.

CONCLUSIONS

Experience of 9 months with this prospective protocol showed its effectiveness in the management of critically ill patients with acute coronary occlusion leading to low mortality rate in acute myocardial infarction and improved survival rate in post-infarction cardiogenic shock.

Acute myocardial infarction. Reperfusion strategies

Acute myocardial infarction is the result of an acute interruption of myocardial blood flow resulting in ischemic myocardial necrosis. The pathogenesis of this phenomenon nearly always involves acute thrombosis superimposed on a disrupted atherosclerotic plaque. Thrombolytic agents have been conclusively shown to reduce mortality in many patient subgroups with myocardial infarction, including the elderly, patients with inferior myocardial infarction, and patients with systolic hypertension. Nearly all patients with acute myocardial infarction of less than 6 h in duration with S-T segment elevation should receive thrombolysis unless significant contraindications exist and outweigh the potential benefits. Aspirin should be given to almost all patients regardless of whether they receive thrombolysis. Angioplasty and coronary artery bypass surgery are useful as primary or secondary modes of reperfusion in selected patients with infarction.

Hemodynamic, mechanical, and metabolic determinants of thrombolytic efficacy: a theoretic framework for assessing the limitations of thrombolysis in patients with cardiogenic shock

Although thrombolytic therapy has been shown to limit infarct size, preserve left ventricular function, and improve survival in most subgroups of patients with acute MI, a benefit has not been demonstrated in patients with clinical left ventricular dysfunction or overt cardiogenic shock before treatment is initiated. The reason(s) for the lack of benefit derived from thrombolytic therapy in these settings is unclear. Left ventricular dysfunction and overt cardiogenic shock are the result of extensive myocardial necrosis, typically in excess of 30% of the left ventricle, which progresses over time. The available data suggest that thrombolytic efficacy is decreased because of either hemodynamic, mechanical, or metabolic factors. As a result coronary patency is rarely achieved in a timely fashion, and if patency is achieved it typically is not maintained. The ability of mechanical revascularization by means of balloon angioplasty to reduce mortality suggests that reperfusion is a key determinant of outcome even among patients with large infarctions and early signs of left ventricular dysfunction. Thrombolytic therapy, which is widely available and extensively tested, represents the standard of care for patients with acute MI. Its apparent lack of efficacy in patients with congestive heart failure and cardiogenic shock is poorly understood. Further investigation must therefore be undertaken.

Risk analysis of operative intervention for failed coronary angioplasty

To assess the outcome of emergency coronary artery bypass grafting (CABG) after failed percutaneous transluminal coronary angioplasty (PTCA), 91 patients undergoing emergency CABG after failed PTCA over a 30-month period ending July 31, 1991, were studied. For reference, a cohort of patients (91) concurrently undergoing elective CABG equally matched for age, sex, number of grafts, ventricular function, and reoperative status was compared. Specific outcomes including death, hospital length of stay, use of blood products, and development of myocardial infarction were analyzed. More than half the patients undergoing emergency CABG for failed PTCA required three or more grafts. Operative mortality was 12.1% (11/99) for emergency CABG compared with 1% (1/91) for elective case-matched CABG patients (p = 0.007). Emergency CABG patients required frequent use of postoperative inotropes (p = 0.02) and intraaortic balloon counterpulsation (p = 0.001). Length of hospital stay (p = 0.005), administration of blood products (p = 0.009), postoperative myocardial infarction (p = 0.0005), and ventricular arrhythmias (p = 0.0004) were increased after emergency compared with elective CABG. The presence of multivessel disease or use of a reperfusion catheter had no influence on clinical outcome. Despite accumulated experience and improved operative management, patients requiring emergency CABG for failed PTCA remain at increased risk for postoperative complications and death.

Early revascularization improves survival in cardiogenic shock complicating acute myocardial infarction

The effects of coronary revascularization by percutaneous transluminal coronary angioplasty or coronary bypass grafting, or both, on survival were evaluated in 81 patients with cardiogenic shock complicating acute myocardial infarction. Thirty-two patients had successful revascularization and 49 patients had unsuccessful or no revascularization. Revascularization was achieved by coronary angioplasty in 22 patients, coronary bypass surgery in 2 and angioplasty followed by bypass surgery in 8. No significant differences were noted between the two groups with regard to baseline clinical or hemodynamic variables. Intraaortic balloon counterpulsation was employed in 27 (84%) of the 32 patients in the group with revascularization and in 19 (39%) of the 49 patients without revascularization (p = 0.0006). The in-hospital survival was significantly better in the patients with--18 (56%) of 32--than in the patients without revascularization--4 (8%) of 49 (p less than 0.0001). At a mean follow-up period of 21 +/- 15 months, this survival difference persisted--16 (50%) of 32 patients with revascularization survived versus 1 (2%) of 49 patients without revascularization (p less than 0.0001). The mean time from the onset of shock to revascularization differed significantly between survivors (12.4 +/- 15 h) and nonsurvivors (58.5 +/- 93 h) in the group with revascularization (p = 0.0004). In the revascularization group, the in-hospital survival rate was 77% (17 of 22) when revascularization was performed within 24 h but only 10% (1 of 10) when it was performed after 24 h (p = 0.0006).(ABSTRACT TRUNCATED AT 250 WORDS)

Percutaneous transluminal coronary angioplasty in patients with cardiogenic shock

In cardiogenic shock complicating acute myocardial infarction, percutaneous transluminal coronary angioplasty has been reported to significantly improve the modest survival benefits afforded by emergency surgical revascularization and thrombolytic therapy. The records of all patients who underwent angioplasty for acute myocardial infarction complicated by cardiogenic shock were retrospectively reviewed to determine whether coronary angioplasty improves survival. Of the 45 patients, 28 (group 1, 62%) had successful dilation of the infarct-related artery and 17 (group 2, 38%) had unsuccessful angioplasty. The groups were similar in extent of coronary artery disease, infarct location, incidence of multivessel disease and hemodynamic variables. The overall hospital survival rate was 56% (71% in group 1 and 29% in group 2). Group 1 patients had more left main coronary artery disease, and group 2 patients were older and had a higher incidence of prior myocardial infarction. Multivariate analysis showed that the survival advantage in patients with successful angioplasty was statistically significant (p = 0.014) when these factors were taken into account. At a mean follow-up interval of 2.3 years (range 1 month to 5.6 years), there were five deaths (four cardiac and one noncardiac), for a 2.3-year survival rate of 80% in patients surviving to hospital discharge. During the follow-up period, 36% of hospital survivors had repeat hospitalization for cardiac evaluation, 8% had myocardial infarction, 8% had coronary artery bypass surgery and 24% had angina.

Limitations of thrombolytic therapy for acute myocardial infarction complicated by congestive heart failure and cardiogenic shock

As many as one quarter of patients treated with thrombolytic therapy present with congestive heart failure or cardiogenic shock. Although thrombolytic therapy has been shown to limit infarct size, preserve left ventricular ejection fraction and decrease mortality in most subgroups of patients, no apparent benefit has been demonstrated in patients with clinical left ventricular dysfunction. The lack of correlation between ejection fraction and other measurements of left ventricular dysfunction such as exercise time, cardiac output, filling pressures, activation of the neurohumoral system and regional perfusion bed abnormalities may partly explain this paradox. Alternatively, lower perfusion rates, higher reocclusion rates, associated mechanical complications or completed infarction may explain these findings. Preliminary data indicate that emergency coronary angioplasty or bypass graft surgery improves survival in selected patients with cardiogenic shock. Because these findings suggest that restoration of infarct artery patency is especially important in patients with clinical left ventricular dysfunction, additional studies are needed in these patients to investigate the potential benefit that new thrombolytic strategies, inotropic or vasodilator agents or intraaortic balloon counterpulsation might offer by augmenting coronary blood flow and improving reperfusion rates. Currently, acute mechanical revascularization should be considered for patients who present with congestive heart failure associated with hypotension or tachycardia and for patients with cardiogenic shock.

Coronary bypass surgery improves global and regional left ventricular function following thrombolytic therapy for acute myocardial infarction. TAMI Study Group

Coronary bypass surgery was performed prior to hospital discharge in 303 (22%) of 1387 consecutive patients enrolled in the TAMI 1 to 3 and 5 trials of intravenous thrombolytic therapy for acute myocardial infarction. Bypass surgery was of emergency nature (less than 24 hours from treatment with intravenous thrombolytic therapy) in 36 (2.6%) and was deferred (greater than 24 hours) in 267 (19.3%) patients. The indications for bypass surgery included failed angioplasty (12%); left main or equivalent coronary disease (9%); complex or multivessel coronary disease (62%); recurrent postinfarction angina (13%); and refractory pump dysfunction, mitral regurgitation, ventricular septal rupture or abnormal predischarge functional test (1% each). Although patients having bypass surgery were older (59.5 +/- 9.8 versus 56.0 +/- 10.2 years, (p less than 0.0001), had more extensive coronary artery disease (46% with three-vessel disease versus 11%, (p less than 0.0001), had more frequent diabetes mellitus (19% versus 15%, (p = 0.048), had more prior infarctions (p less than 0.0001), had more severe initial depression in global left ventricular ejection fraction (48.0 +/- 11.9% versus 51.8 +/- 11.9%, p = 0.0002), and regional infarct zone (-2.7 +/- 0.94 versus -2.5 +/- 1.1 SD/chord, p = 0.02) and noninfarct zone function (-0.36 +/- 1.8 versus 0.43 +/- 1.6 SD/chord, p less than 0.0001) than patients not having coronary bypass surgery, no difference in the incidence of death in hospital (7% surgical versus 6% nonsurgical) or death at long-term follow-up of hospital survivors (7% surgical versus 6% nonsurgical) was noted between groups. Surgical patients demonstrated a greater degree of recovery in left ventricular ejection fraction (3.4 +/- 9.8% versus 0.16 +/- 8.5%, p = 0.036) and infarct zone regional function (0.71 +/- 1.1 versus 0.34 +/- 0.99 SD/chord, p = 0.001) when immediate (90 minutes following initiation of thrombolytic therapy) and predischarge (7 to 14 days after treatment) contrast left ventriculograms were compared than did patients who received only intravenous thrombolytic therapy with or without coronary angioplasty. These data suggest a beneficial influence of coronary bypass surgery on left ventricular function and possibly on the clinical outcome of patients initially treated with intravenous thrombolytic therapy for acute myocardial infarction.

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.

Feasibility of intraoperative aortic root angiography in the identification of critical coronary lesions

Early revascularization is critical for the treatment of acute myocardial infarction (AMI) because the ischemic myocardium begins to suffer irreversible damage after 4 h from the onset of symptoms. However, to make a diagnosis, perform coronary angiography, and prepare for operative revascularization usually takes longer than 4 h. Also, once a patient develops severe cardiogenic shock, coronary angiography is often impossible. Without angiography, the patient is no longer a candidate for surgical repair. To circumvent this problem, we designed this experiment to determine whether intraoperative aortic root angiography after cardiopulmonary bypass and cardioplegic arrest could satisfactorily substitute for angiographic examination in the identification of critical coronary lesions. The feasibility of this approach was tested in dog hearts in which one or tow of the major coronary arteries were ligated. The ascending aorta was then clamped, contrast material was injected, and continuous real-time fluoroscopic images were obtained and recorded on videotape. The videotape was then analyzed by three physicians independently, each without prior knowledge of the lesion locations. Lesions of the left anterior descending artery, the circumflex coronary artery, and the right coronary artery were identified with 94, 91, and 94% accuracy, respectively, for an overall identification rate of 92%. We conclude that aortic root angiography reliably demonstrates coronary artery lesions, and refinements in this technique may allow certain patients to undergo coronary operations without preoperative catheterization.

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)

Reperfusion of infarcting myocardium: benefit of surgical reperfusion in a chronic model

Surgical reperfusion of experimental infarction leads to improved recovery of regional function compared with medical reperfusion, but sustained myocardial salvage has not been demonstrated. Twenty-two dogs were subjected to two hours of anterior descending occlusion and divided into three groups: group P (n = 7), no reperfusion; group M (n = 8), medical reperfusion; and group S (n = 7), controlled surgical reperfusion. Ischemia caused systolic bulging (-36% of control systolic shortening, p less than 0.01) and decreased regional work (9% of control pressure-length loop area, p less than 0.05). Thirty minutes after reperfusion group M had persistent systolic bulging (-9% of control systolic shortening) and decreased regional work (9% of control pressure-length loop area), whereas group S had +17% of control systolic shortening and 33% of control pressure-length loop area. After 1 week, regional function improved in all three groups (percent of control systolic shortening: group P, 26%; group M, 19%; group S, 52%), but systolic shortening was significantly better in group S (p less than 0.05 versus group M). Surgical reperfusion also resulted in one half of the eventual myocardial necrosis found in the other groups (group P, 45% of area at risk; group M, 38%; group S, 19%; p less than 0.05, group S versus group P or M). In this model, medical reperfusion offered no demonstrable benefit, whereas controlled surgical reperfusion led to a sustained (1 week) improvement in regional function and significant myocardial salvage.

Favorable early and long-term prognosis following coronary bypass surgery therapy for myocardial infarction: results of a multicenter trial. TAMI Study Group

Coronary bypass surgery was performed before hospital discharge on 82 (21%) of 386 consecutive patients enrolled in the Thrombolysis and Angioplasty in Myocardial Infarction (TAMI) multicenter trial of intravenous tissue plasminogen activator and coronary angioplasty for acute myocardial infarction. Time from infarct symptom onset to coronary bypass surgery was 7.3 +/- 1.9 hours for 24 patients operated upon on an emergency basis and 9.3 +/- 5.2 days for 58 patients having late in-hospital surgery. There were no operative deaths and five in-hospital deaths in the surgical group, all of which occurred in patients with preoperative cardiogenic shock. Although patients in the surgical group were older (59.7 +/- 10.4 years versus 54.9 +/- 10.2 years; p = 0.03), had more extensive coronary artery disease (42% three-vessel disease versus 11%; p = 0.001), and had a higher incidence of anterior wall myocardial infarction (48% versus 39%; p = 0.02), in-hospital mortality for the surgical group (6%) was similar to that in 301 patients not undergoing surgery (7%) in this trial. For patients discharged from the hospital, mortality at 1 year was 2.5% in the surgical group and 1.8% in patients not having coronary bypass surgery before hospital discharge. At a 1 year follow-up, there were no significant differences in the frequency of cardiac or noncardiac-related hospitalizations or in event-free survival between surgical and nonsurgical groups. The majority of patients in both groups considered themselves to be in excellent or good condition. Coronary bypass surgery can be performed with low morbidity and mortality rates in close temporal association to acute myocardial infarction.(ABSTRACT TRUNCATED AT 250 WORDS)

Disrupted coronary artery caused by angioplasty: supportive and surgical considerations

Of 2,859 patients having percutaneous transluminal coronary angioplasty, 201 (7%) underwent emergency coronary artery bypass grafting. Two categories of patients were reviewed. Group 1 consisted of 126 patients of 2,304 who had immediate coronary artery bypass grafting after failed elective percutaneous transluminal coronary angioplasty. Ninety-eight of these patients had angiographic evidence of occlusion of a coronary artery, and 28 had angiographic evidence of coronary artery dissection. Epicardial hemorrhage was observed at operation in 20% (25 patients). Three deaths (2.4%) occurred in group 1, and an average of 3.3 grafts was performed per patient. Group 2 comprised 75 of 555 patients who had unsuccessful attempted percutaneous transluminal coronary angioplasty during an evolving myocardial infarction and required immediate coronary artery bypass grafting. Angiography revealed coronary artery occlusion in 61 patients with dissection in 14. All group 2 patients had evidence of myocardial injury by electrocardiographic and enzymatic (myocardial-specific isoenzyme of creatine kinase) criteria. Three deaths (4%) occurred in this group, and there was an average of 3.4 grafts per patient. Percutaneous transluminal coronary angioplasty is routinely performed without surgical consultation, although an operating room and team are usually available. Supportive techniques include the intraaortic balloon pump and percutaneous cardiopulmonary bypass. In those patients with coronary artery dissection, care must be taken to reestablish the true lumen of the coronary artery. Hemopericardium should be surgically explored and broken guidewires or other foreign bodies or debris removed. From 1979 through 1986, the number of patients requiring emergency coronary artery bypass grafting after percutaneous transluminal coronary angioplasty steadily declined to less than 5%.

Emergency coronary artery bypass surgery preserves global and regional left ventricular function after intravenous tissue plasminogen activator therapy for acute myocardial infarction

Emergency coronary bypass surgery was performed in 24 (6.2%) of 386 consecutive patients enrolled in the Thrombolysis and Angioplasty in Myocardial Infarction (TAMI) Multicenter Trial. Intravenous tissue plasminogen activator was administered 2.6 +/- 0.7 h and bypass surgery was performed 7.3 +/- 1.9 h after the onset of infarction. Infarct artery patency was achieved in 21 (88%) of the 24 patients (pharmacologically in 18 or mechanically with coronary angioplasty in 3) in the catheterization laboratory before bypass surgery. The indication for surgery was left main or equivalent coronary artery disease in 7 patients, coronary anatomy unsuitable for angioplasty in 4 patients and unsuccessful coronary angioplasty in 13 patients. A coronary perfusion catheter was inserted before surgery in 11 of 13 patients with unsuccessful angioplasty. All three deaths occurred postoperatively in patients with preoperative cardiogenic shock. Three patients required surgical reexploration for postoperative hemorrhage. Comparison of preoperative and predischarge contrast left ventriculograms demonstrated significant preservation of global (left ventricular ejection fraction 49 +/- 6 to 56 +/- 6%; p = 0.008) and regional (standard deviation/chord -2.6 +/- 0.5 to -1.5 +/- 1.1; p = 0.001) left ventricular function. Emergency coronary bypass surgery can be performed with a low morbidity and mortality in patients treated with intravenous tissue plasminogen activator therapy for acute myocardial infarction. Such therapy is associated with significant preservation of global and regional (infarct zone) left ventricular function.

Anesthetic implications for the management of patients with acute myocardial infarction: a matched cohort study of patients undergoing emergency myocardial revascularization

Emergency coronary artery bypass grafting (CABG) is advocated as a treatment of acute myocardial infarction (AMI). To attempt to define anesthetic management problems in this patient group, a retrospective study was conducted comparing the perioperative courses of 23 patients undergoing emergency CABG during AMI with 23 elective patients, individually matched for gender, operating surgeon, ejection fraction, and aortic crossclamp time. The 23 AMI patients were anesthetized 5.98 +/- 3.0 (range 1.5 to 11.0) hours after the onset of chest pain. Anesthetic agents were similar for both groups. Induction of anesthesia was well tolerated by AMI patients. Tolerance of cardioplegic arrest was impaired in the AMI group as evidenced by the sharp increase in frequency of inotropic support required to discontinue bypass in the AMI group compared to elective patients (12/23 v 3/23; P less than .005). Fifteen AMI patients who received preoperative streptokinase had greater postoperative bleeding. Three AMI patients died postoperatively. The number of patients requiring prolonged postoperative ventilation and extended ICU care was higher in the AMI group. It is concluded that patients undergoing emergency CABG during AMI represent a greater risk than elective patients. They have a higher incidence of myocardial dysfunction following cardioplegic arrest during bypass. Those who receive preoperative thrombolytic therapy exhibit greater bleeding tendencies.