Current spectrum of cardiogenic shock and effect of early revascularization on mortality. Results of an International Registry. SHOCK Registry Investigators

Cardiogenic shock

Mortality rates in patients with cardiogenic shock remain frustratingly high. Its pathophysiology involves a downward spiral in which ischemia causes myocardial dysfunction, which in turn worsens ischemia. Areas of viable but nonfunctional myocardium can contribute to the development of cardiogenic shock. Rapid diagnosis and prompt initiation of supportive therapy to maintain blood pressure and cardiac output, followed by expeditious coronary revascularization, are crucial. The SHOCK multicenter randomized trial has provided important new data that support a strategy of emergent cardiac catheterization and revascularization with angioplasty or coronary surgery when feasible. This strategy can improve survival and represents standard therapy at this time. In hospitals without direct angioplasty capability, stabilization with IABP and thrombolysis followed by transfer to a tertiary care facility may be the best option.

Appropriate indications for the use of a percutaneous cardiopulmonary support system in cases with cardiogenic shock complicating acute myocardial infarction

Percutaneous cardiopulmonary support (PCPS) is now available for hemodynamic support in patients with cardiogenic shock, but there are no guidelines for its use. The present study determined the appropriate indications for the use of the PCPS in patients with cardiogenic shock complicating acute myocardial infarction (AMI). Sixty-four consecutive patients with cardiogenic shock complicating AMI had hemodynamic support with an intraaortic balloon pump (IABP; n=38) and/or PCPS (n=26). The shock score (0-15) was calculated immediately before starting these support systems to quantify the severity of shock. Multivariate logistic regression analysis determined the clinical factors affecting in-hospital mortality. The relationship between in-hospital prognosis and the shock score was also examined in the 2 groups. The most significant factor related to the in-hospital prognosis was the shock score (p=0.0007; OR 2.16, 95% CI: 1.37-3.39). Another related factor was revascularization; however, this relationship did not reach statistical significance (p=0.069; OR 0.06). Among the 13 cases whose shock score was 4-8 (moderate shock), 5 survived in the PCPS group, but only 1 of 19 patients survived in the IABP group (p<0.05). None of the patients in either group whose shock score was more than 9 survived. The severity of shock is the most reliable independent predictor of in-hospital mortality in patients with cardiogenic shock complicating AMI. Using PCPS in patients with moderate cardiogenic shock may improve their in-hospital survival, but it must be used before the shock becomes severe.

Improved survival of patients with acute myocardial infarction with significant left ventricular dysfunction undergoing invasive coronary procedures

BACKGROUND

Acute myocardial infarction (AMI) associated with significant left ventricular dysfunction (LVD) indicates a poor prognosis. Previous studies suggested that revascularization improves survival of patients with AMI complicated by cardiogenic shock. However, other studies that suggested that revascularization improves survival of stable patients with significant LVD did not specifically address patients who had recently had an AMI.

OBJECTIVES

Our purpose was to determine whether patients with thrombolysis-treated AMI associated with significant LVD are likely to incur a survival advantage from catheterization and coronary revascularization performed within 30 days after AMI.

METHODS

The study population was drawn from the Argatroban in Acute Myocardial Infarction-2 (ARGAMI-2) trial, which included 1200 patients with AMI, all of whom received thrombolytic therapy. Our analysis included 737 patients for whom LV function was estimated by echocardiography. Two hundred two patients had significant LVD; of them, 117 (58%) underwent cardiac catheterization and 85 were treated noninvasively. Among 535 patients without significant LVD, 291 (54%) underwent cardiac catheterization and 244 were treated noninvasively.

RESULTS

Compared with a noninvasive approach, an invasive approach resulted in reduced 30-day and 6-month mortality rates in patients with significant LVD: 4.3% versus 10.6%, adjusted odds ratio (OR) 0.26, 95% confidence interval (CI) 0.04 to 1.18, and 6.1% versus 15.5%, OR 0.27, 95% CI 0.06 to 0.98, respectively. A similar comparison in patients without significant LVD resulted in comparable 30-day and 6-month mortality rates for both patient groups: invasively versus noninvasively treated, 0.7% versus 0.8%, OR 1.04, 95% CI 0.04 to 12.7, and 1.4% versus 1.7%, adjusted OR 1.60, 95% CI 0.20 to 9.87.

CONCLUSIONS

The current study suggests that AMI patients with significant LVD may benefit from cardiac catheterization and revascularization performed early after AMI, whereas in patients without significant LVD the outcome of those treated invasively or conservatively was similar.

Recent magnitude of and temporal trends (1994-1997) in the incidence and hospital death rates of cardiogenic shock complicating acute myocardial infarction: the second national registry of myocardial infarction

BACKGROUND

Limited recent data are available to describe the magnitude of, and temporal trends in, the incidence and case-fatality rates associated with cardiogenic shock complicating acute myocardial infarction. The purpose of this study was to examine recent (1994-1997) trends in the incidence of, and hospital death rates from, cardiogenic shock complicating acute myocardial infarction from a large, multihospital national perspective.

METHODS

An observational study was performed of 426,253 patients hospitalized with acute myocardial infarction in 1662 hospitals throughout the United States between 1994 and 1997.

RESULTS

The incidence rates of cardiogenic shock averaged 6.2%. There was evidence for a slight decline in these rates between 1994 (6.6%) and 1997 (6.0%). Results of a multivariable regression analysis controlling for factors that might affect the risk of development of cardiogenic shock indicated that patients hospitalized in more recent years were at significantly lower risk for shock. Patients with shock had a markedly increased risk for dying during hospitalization compared with patients not having shock (74% vs 10%). Significant, albeit small, absolute differences were observed in the risk of dying after cardiogenic shock over time (76% dying in 1997, 72% dying in 1994). These improving trends were magnified, however, after potentially confounding prognostic factors were controlled: patients having shock in 1997 were at approximately one fifth lower risk of dying (odds ratio 0.79, 95% confidence interval 0.71-0.87) than those hospitalized in 1994.

CONCLUSIONS

Our findings indicate a slight decline in the incidence rates of cardiogenic shock and improving trends in the hospital survival of patients with shock. Despite these trends, it remains of considerable importance to prevent this clinical syndrome, given its high lethality.

[Coronary angioplasty in the acute myocardial infarction: in which patients is it less likely to obtain an adequate coronary reperfusion?]

INTRODUCTION

In patients with acute myocardial infarction treated with primary angioplasty, the inability to achieve successful coronary reperfusion is associated with higher mortality. The objective of the study was to identify which characteristics may predict a lower angiographic success rate in patients with acute myocardial infarction treated with coronary angioplasty.

PATIENTS AND METHODS

The study population is constituted by the 790 patients with acute myocardial infarction that were treated with angioplasty within the 12 hours after the onset of symptoms from 1991 to 1999 at our institution. A successful angiographic result was considered in presence of a residual stenosis < 50% and a TIMI flow 2 or 3 after the procedure.

RESULTS

A successful angiographic result and a final TIMI 3 flow were achieved in 736 (93.2%) and 652 (82.5%) patients, respectively. In-hospital mortality was higher in patients with angiographic failure than in those with angiographic successful result (48 vs. 10%; p < 0.01). Age under 65 (91 vs. 95%; p = 0.02), non smoking (90 vs. 96%; p < 0,01), previous infarction (87 vs. 94%; p < 0.01), angioplasty after failed thrombolysis (83 vs. 94%; p = 0. 02), cardiogenic shock (80 vs. 95%; p < 0.01), undetermined location (67 vs. 93%; p < 0.01), non-inferior location (92 vs. 96%; p = 0.04), left bundle branch block (64 vs. 94%; p < 0.01), multivessel disease (91 vs. 95%; p = 0.02), left ventricular ejection fraction < 0.40 (89 vs. 97%; p < 0.01), no utilization of coronary stenting (90 vs. 96%; p < 0.01), and use of intraaortic balloon counterpulsation pump (82 vs. 95%; p < 0.01) were associated with a lower angiographic success rate. In the multivariable analysis, the following were independent predictors for angiographic failure: left bundle branch block (odds ratio [OR], 12.95; CI 95%, 3.00-53.90), cardiogenic shock (OR, 4.20; CI 95%, 1.95-8.75), no utilization of coronary stent (OR, 3.44; CI 95%, 1.71-7.37), and previous infarction (OR, 2.82; CI 95%, 1.29-5.90).

CONCLUSIONS

Coronary angioplasty allows a successful coronary recanalization in most patients with acute myocardial infarction. Some basic characteristics, however, may identify some subsets in which a successful angiographic result may be more difficult to obtain.

Implications of the timing of onset of cardiogenic shock after acute myocardial infarction: a report from the SHOCK Trial Registry. SHould we emergently revascularize Occluded Coronaries for cardiogenic shocK?

OBJECTIVES

We sought to examine the implications of the timing of onset of cardiogenic shock (CS) after acute myocardial infarction (MI).

BACKGROUND

Little information is available about the relationships between timing, clinical substrate, management and outcomes of shock.

METHODS

The multinational SHOCK Trial Registry enrolled MI patients with CS from 1993 to 1997. Cardiogenic shock was predominantly attributable to left ventricular (LV) failure in 815 Registry patients for whom temporal data were available. We examined factors related to the timing of shock onset and the relation of temporal onset to in-hospital outcomes.

RESULTS

Overall, shock developed a median of 6.2 h after MI symptom onset. Shock onset varied by culprit artery: left main, median 1.7 h; right, 3.5 h; circumflex, 3.9 h; left anterior descending (LAD), 11.0 h; saphenous vein graft, 10.9 h (p = 0.025). Early shock (< 24 h) occurred in 74.1% and was associated with chest pain at shock onset, ST-segment elevation in two or more leads, multiple infarct locations, inferior MI, left main disease and smoking. Late shock (> or = 24 h) was associated with recurrent ischemia, Q waves in two or more leads and LAD culprit vessel. Mortality was higher in patients with early versus late shock (62.6% vs. 53.6%, p = 0.022).

CONCLUSIONS

Shock onset after acute MI occurred within 24 h in 74% of the patients with predominant LV failure. Mortality was slightly higher in patients developing shock early rather than later. Many factors influence when shock develops, which has implications for its management.

Cardiogenic shock due to acute severe mitral regurgitation complicating acute myocardial infarction: a report from the SHOCK Trial Registry. SHould we use emergently revascularize Occluded Coronaries in cardiogenic shocK?

OBJECTIVES

Our objective was to define the outcomes of patients with cardiogenic shock (CS) due to severe mitral regurgitation (MR) complicating acute myocardial infarction (AMI).

BACKGROUND

Methods for early identification and optimal treatment of such patients have not been defined.

METHODS

The SHOCK Trial Registry enrolled 1,190 patients with CS complicating AMI. We compared 1) the cohort with severe mitral regurgitation (MR, n = 98) to the cohort with predominant left ventricular failure (LVF, n = 879), and 2) the MR patients who underwent valve surgery (n = 43) to those who did not (n = 51).

RESULTS

Shock developed early after MI in both the MR (median 12.8 h) and LVF (median 6.2 h) cohorts. The MR patients were more often female (52% vs. 37%, p = 0.004) and less likely to have ST elevation at shock diagnosis (41% vs. 63%, p < 0.001). The MR index MI was more frequently inferior (55% vs. 44%, p = 0.039) or posterior (32% vs. 17%, p = 0.002) than that of LVF and much less frequently anterior (34% vs. 59%, p < 0.001). Despite having higher mean LVEF (0.37 vs. 0.30, p = 0.001) the MR cohort had similar in-hospital mortality (55% vs. 61%, p = 0.277). The majority of MR patients did not undergo mitral valve surgery. Those undergoing surgery exhibited higher mean LVEF than those not undergoing surgery; nevertheless, 39% died in hospital.

CONCLUSIONS

The data highlight opportunities for early identification and intervention to potentially decrease the devastating mortality and morbidity of severe post-myocardial infarction MR.

Cardiogenic shock with non-ST-segment elevation myocardial infarction: a report from the SHOCK Trial Registry. SHould we emergently revascularize Occluded coronaries for Cardiogenic shocK?

OBJECTIVES

We sought to determine the outcomes of patients with cardiogenic shock (CS) complicating non-ST-segment elevation acute myocardial infarction (MI).

BACKGROUND

Such patients represent a high-risk (ST-segment depression) or low-risk (normal or nonspecific electrocardiographic findings) group for whom optimal therapy, particularly in the setting of shock, is unknown.

METHODS

We assessed characteristics and outcomes of 881 patients with CS due to predominant left ventricular (LV) dysfunction in the SHOCK Trial Registry.

RESULTS

Patients with non-ST-segment elevation MI (n = 152) were significantly older and had significantly more prior MI, heart failure, azotemia, bypass surgery, and peripheral vascular disease than patients with ST-elevation MI (n = 729). On average, the groups had similar in-hospital LV ejection fractions (approximately 30%), but patients with non-ST-elevation MI had a lower highest creatine kinase and were more likely to have triple-vessel disease. Among patients selected for coronary angiography, the left circumflex artery was the culprit vessel in 34.6% of non-ST-elevation versus 13.4% of ST-elevation MI patients (p = 0.001). Despite having more recurrent ischemia (25.7% vs. 17.4%, p = 0.058), non-ST-elevation patients underwent angiography less often (52.6% vs. 64.1%, p = 0.010). The proportion undergoing revascularization was similar (36.8% for non-ST-elevation vs. 41.9% ST-elevation MI, p = 0.277). In-hospital mortality also was similar in the two groups (62.5% for non-ST-elevation vs. 60.4% ST-elevation MI). After adjustment, ST-segment elevation MI did not independently predict in-hospital mortality (odds ratio, 1.30; 95% confidence interval, 0.83 to 2.02; p = 0.252).

CONCLUSIONS

Patients with CS and non-ST-segment elevation MI have a higher-risk profile than shock patients with ST-segment elevation, but similar in-hospital mortality. More recurrent ischemia and less angiography represent opportunities for earlier intervention, and early reperfusion therapy for circumflex artery occlusion should be considered when non-ST-elevation MI causes CS.

Diabetes mellitus 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 examine the role of diabetes mellitus in cardiogenic shock (CS) complicating acute myocardial infarction (AMI) in the SHOCK Trial Registry.

BACKGROUND

The characteristics, outcomes and optimal treatment of diabetic patients with CS complicating AMI have not been well described.

METHODS

Baseline characteristics, clinical and hemodynamic measures, treatment variables, shock etiologies and comorbid conditions were compared for 379 diabetic and 784 nondiabetic patients. Logistic regression was used to examine the association between diabetes and in-hospital mortality, after adjustment for baseline differences.

RESULTS

Diabetics were less likely than nondiabetics to undergo thrombolysis (28% vs. 37%; p = 0.002) or attempted revascularization (40% vs. 49%; p = 0.008). The survival benefit for diabetics selected for percutaneous or surgical revascularization (55% vs. 19% without revascularization) was similar to that for nondiabetics (59% vs. 25%). Overall unadjusted in-hospital mortality was significantly higher for diabetics (67% vs. 58%; p = 0.007), but diabetes was only a borderline predictor of mortality after adjustment for baseline and treatment differences (odds ratio for death, 1.36; 95% confidence interval, 1.00 to 1.84; p = 0.051).

CONCLUSIONS

Diabetics with CS complicating AMI have a higher-risk profile at baseline, but after adjustment, diabetics have an in-hospital survival rate that is only marginally lower than that of nondiabetics. Diabetics who undergo revascularization derive a survival benefit similar to that of nondiabetics.

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.

Cardiogenic shock complicating acute coronary syndromes

Cardiogenic shock remains the major cause of death among patients with all types of acute coronary syndromes. Thus, there is a growing interest in the identification of patients who are at risk for developing cardiogenic shock, in the exploration of different therapeutic approaches to preventing its development, and in the improvement of outcome when it occurs. This article reviews the aetiology and pathophysiology of cardiogenic shock, its epidemiology, its treatment (including pharmaceutical agents, counterpulsation, and revascularisation), and its outcome. Algorithms are presented that predict its occurrence in both ST-segment-elevation myocardial infarction and unstable angina or non-ST-elevation myocardial infarction, and that predict its mortality in patients with ST-segment-elevation acute myocardial infarction. Such new areas as metabolic therapy and glycoprotein IIb/IIIa inhibitors are discussed, as are the economic implications of shock.

Failed thrombolysis in myocardial infarction

Prompt treatment with thrombolytic therapy in acute myocardial infarction has been proven to reduce infarct size and mortality. However, reperfusion fails to occur in 30-50% of patients, either due to impaired epicardial artery flow or microvascular occlusion, with these patients experiencing a higher morbidity and mortality. We review the diagnosis and management of failed thrombolysis in acute myocardial infarction.

Effect of early revascularization on mortality from cardiogenic shock complicating acute myocardial infarction in California

Recent retrospective analyses of treatment of cardiogenic shock suggest that early revascularization reduces mortality. All nonfederal hospital admissions in California for 1994 with a diagnosis of acute myocardial infarction (AMI) were identified. From that cohort, patients who developed cardiogenic shock were selected to determine demographic features, procedure utilization, and outcomes of their admission compared with patients with AMI without cardiogenic shock. Multivariate logistic regression analysis was performed to assess the effect of early revascularization on survival of patients in cardiogenic shock. Cardiogenic shock was identified in 1,122 patients. Mean age was 70.4 years, 45% of patients were women, and 28% had diabetes mellitus. Shock patients were more likely to be older, diabetic, women, and having an anterior Q-wave AMI. Overall in-hospital mortality for patients with shock was 56%. Patients referred for early revascularization had more favorable risk profiles, but after multivariate analysis early revascularization remained a powerful, independent predictor of improved survival, reducing the odds of death by 80%. This population-based study suggests that early revascularization may improve in-hospital survival of patients with cardiogenic shock complicating AMI, even after adjustment for baseline differences between patients who underwent early revascularization and those who did not.

Acute myocardial infarction complicated by systemic hypoperfusion without hypotension: report of the SHOCK trial registry

BACKGROUND

Cardiogenic shock is usually characterized by inadequate cardiac output and sustained hypotension. However, following a large myocardial infarction, peripheral hypoperfusion can occur with relatively well maintained systolic blood pressure, a condition known as nonhypotensive cardiogenic shock. The aim of this study was to determine the characteristics of patients with this condition.

METHODS

The SHOCK trial registry prospectively enrolled patients with suspected cardiogenic shock complicating acute myocardial infarction. We identified a group of 49 patients who presented with nonhypotensive shock, defined as clinical evidence of peripheral hypoperfusion with a systolic blood pressure >90 mm Hg without vasopressor circulatory support. Clinical characteristics, hemodynamic data, and outcomes in these patients were compared with a group of 943 patients with classic cardiogenic shock with hypotension. The age, gender, and distributions of coronary risk factors were similar in both groups.

RESULTS

Patients with nonhypotensive shock were more likely to have an anterior wall myocardial infarction (71% versus 53%, P = 0.03). Both groups of patients had similar rates of treatment with thrombolytic therapy, angioplasty, and bypass surgery. Patients with nonhypotensive shock had an in-hospital mortality rate of 43% as compared with a rate of 66% among patients who had classic cardiogenic shock with hypotension (P = 0.001). Mortality among 76 patients who presented with a systolic blood pressure <90 mm Hg but no hypoperfusion was 26%.

CONCLUSIONS

Even in the presence of normal blood pressure, clinical signs of peripheral hypoperfusion, which may be subtle, are associated with a substantial risk of in-hospital death following acute myocardial infarction.

Thrombolysis in Acute Myocardial Infarction Complicated by Cardiogenic Shock

The adverse impact of the development of cardiogenic shock in the setting of acute myocardial infarction was first described by Killip and Kimball in 1967. While the in-hospital mortality rate in patients with myocardial infarction and no evidence of heart failure was only 6%, the mortality rate in those patients who developed cardiogenic shock was 81%. Despite advances in cardiovascular care and therapy since that initial report, including universal institution of cardiac care units, advances in hemodynamic monitoring, new inotropic and vasodilating agents, and even increasing utilization of thrombolytic therapy, the mortality from acute myocardial infarction, when complicated by cardiogenic shock, remains disturbingly high, and cardiogenic shock remains the leading cause of death of hospitalized patients following acute myocardial infarction.The grave prognosis associated with this condition has resulted in increased interest in potential therapeutic interventions, particularly in the area of reperfusion therapy. Several studies suggest that, in contrast to the beneficial effects of thrombolytic therapy in most patient populations suffering acute myocardial infarction, mortality rates are not decreased in those patients with cardiogenic shock at the time of lytic administration. Thrombolytic administration does, however, appear to lead to a modest reduction in the percent of patients with myocardial infarction who will subsequently develop cardiogenic shock during hospitalization.Reperfusion rates with lytic therapy in patients with cardiogenic shock are disappointingly low, in the range of 42-48%, significantly lower than those achieved in patients without cardiogenic shock. These low perfusion rates may, in part, be explained by decreased coronary blood flow and perfusion pressure in patients with left ventricular pump failure.Although promising as adjunctive therapy, it is unclear whether institution of balloon counterpulsation has any long-term benefit in patients with cardiogenic shock treated with thrombolytic therapy. Whether other or additional interventions, such as coronary angioplasty and coronary artery bypass graft (CABG), decrease mortality rates in patients with cardiogenic shock remains to be determined.

Predictors of cardiogenic shock after thrombolytic therapy for acute myocardial infarction

OBJECTIVES

This study characterized clinical factors predictive of cardiogenic shock developing after thrombolytic therapy for acute myocardial infarction (AMI).

BACKGROUND

Cardiogenic shock remains a common and ominous complication of AMI. By identifying patients at risk of developing shock, preventive measures may be implemented to avert its development.

METHODS

We analyzed baseline variables associated with the development of shock after thrombolytic therapy in the Global Utilization of Streptikonase and Tissue-Plasminogen Activator for Occluded Coronary Arteries (GUSTO-I) trial. Using a Cox proportional hazards model, we devised a scoring system predicting the risk of shock. This model was then validated in the Global Use of Strategies to Open Occluded Coronary Arteries (GUSTO-III) cohort.

RESULTS

Shock developed in 1,889 patients a median of 11.6 h after enrollment. The major factors associated with increased adjusted risk of shock were age (chi2 = 285, hazard ratio [95% confidence interval] 1.47 [1.40, 1.53]), systolic blood pressure (chi2 = 280), heart rate (chi2 = 225) and Killip class (chi2 = 161, hazard ratio 1.70 [1.52, 1.90] and 2.95 [2.39, 3.63] for Killip II versus I and Killip III versus I, respectively) upon presentation. Together, these four variables accounted for >85% of the predictive information. These findings were transformed into an algorithm with a validated concordance index of 0.758. Applied to the GUSTO-III cohort, the four variables accounted for > 95% of the predictive information, and the validated concordance index was 0.796.

CONCLUSIONS

A scoring system accurately predicts the risk of shock after thrombolytic therapy for AMI based primarily on the patient's age and physical examination on presentation.

Risk stratification after acute myocardial infarction in the reperfusion era

Historically, risk stratification for survivors of acute myocardial infarction (AMI) has centered on 3 principles: assessment of left ventricular function, detection of residual myocardial ischemia, and estimation of the risk for sudden cardiac death. Although these factors still have important prognostic implications for these patients, our ability to predict adverse cardiac events has significantly improved over the last several years. Recent studies have identified powerful predictors of adverse cardiac events available from the patient history, physical examination, initial electrocardiogram, and blood testing early in the evaluation of patients with AMI. Numerous studies performed in patients receiving early reperfusion therapy with either thrombolysis or primary angioplasty have emphasized the importance of a patent infarct related artery for long-term survival. The predictive value of a variety of noninvasive and invasive tests to predict myocardial electrical instability have been under active investigation in patients receiving early reperfusion therapy. The current understanding of the clinically important predictors of clinical outcomes in survivors of AMI is reviewed in this article.

[The clinical management guidelines of the Sociedad Española de Cardiología in acute myocardial infarct]

In the recent years, new possibilities have emerged in the diagnosis and management of acute myocardial infarction with ST segment elevation and its complications. Moreover, a deep transformation has taken place in the health care system organization, particularly in aspects related to care of patients presenting non-traumatic chest pain, both in pre-hospital and hospital areas. All these issues warrant a consensus document in Spain dealing with the role that these important changes should play in the whole management of myocardial infarction patients. This document revises and updates all the main clinical issues of acute myocardial infarction patients from the moment they contact with the health care system outside the hospital until they return home, after staying at the coronary care unit and the general hospitalization ward. All those aspects are considered not only in the uncomplicated myocardial infarction but also in the complicated one. This review also includes a set of recommendations on structural and organisational aspects, mainly referred to the prehospital and emergency levels.

[Reperfusion therapy and mechanical circulatory support in patients in cardiogenic shock]

Cardiogenic shock is a state of inadequate tissue perfusion due to cardiac dysfunction, which is most commonly caused by acute myocardial infarction. The pathophysiology of cardiogenic shock is characterized by a downward spiral: ischemia causes myocardial dysfunction, which, in turn, augments the ischemic damage and the energetical imbalance. With conservative therapy, mortality rates for patients with cardiogenic shock are frustratingly high reaching more than 80%. Additional thrombolytic therapy has not been shown to significantly improve survival in such patients. Emergency cardiac catheterization and coronary angioplasty, however, seem to improve the outcome in shock-patients, which most probably is due to rapid and complete revascularization generally reached by angioplasty. In addition to interventional therapy with rapid coronary revascularization, the use of mechanical circulatory support may interrupt the vicious cycle in cardiogenic shock by stabilizing hemodynamics and the metabolic situation. Different cardiac assist devices are available for cardiologists and cardiac surgeons: 1. intraaortic balloon counterpulsation (IABP), 2. implantable turbine-pump (Hemopump), 3. percutaneous cardiopulmonary bypass support (CPS), 4. right heart, left heart, or biventricular assist devices placed by thoracotomy, and 5. intra- and extrathoracic total artificial hearts. Since percutaneous application is possible with IABP, Hemopump and CPS, these devices are currently used in interventional cardiology. The basic goals of the less invasive intraaortic balloon counterpulsation (IABP; Figure 1) are to stabilize circulatory collapse, to increase coronary perfusion and myocardial oxygen supply, and to decrease left ventricular workload and myocardial oxygen demand (Figure 2). Since the advent of percutaneous placement, IABP has been used by an increasing number of institutions (Figure 3). In addition to cardiogenic shock, the system may be of use in a variety of other indications in the catheterization laboratory and intensive care unit, including weaning from percutaneous cardiopulmonary bypass, in ischaemic left ventricular failure, in unstable angina, in high risk PTCA, and in prophylactic support in patients with myocardial infarction and successful revascularization. Animal experimental data showed that IABP may improve success of thrombolysis and recent clinical data suggest that survival is enhanced and transfer for revascularization is facilitated when patients with myocardial infarction and cardiogenic shock undergo thrombolysis and IABP rather than thrombolysis alone. A lot of studies had demonstrated before, that combined use of counterpulsation and revascularization therapy (i.e. coronary bypass surgery or angioplasty) may improve prognosis in patients with myocardial infarction complicated by cardiogenic shock (Table 1). In such patients, early treatment with IABP is most important: Multivariate analysis identified early IABP-support with a duration of shock to IABP-treatment of > or = 4 hours as an independent predictor of a positive short-term outcome. In shock-patients with postinfarction ventricular septal defect, IABP provides a marked hemodynamic improvement, and a significant decrease in shunt-flow (Figure 5). However, despite initial stabilization with IABP, such patients need immediate surgical repair of the septal defect to avoid hemodynamic deterioration. The rate of complications related to percutaneous IABP was significantly attenuated by employing catheters of reduced size. Using 9.5-F catheters, a long duration of counterpulsation emerged as the most significant factor associated with complications. In our hospital, those patients with 9.5-F catheters in whom counterpulsation did not exceed 48 hours had a low complication rate of 3.9%. The Hemopump is a catheter-mounted transvalvular left ventricular assist device intended for surgical placement via the femoral artery (Figures 6 and 7). (ABSTRACT TRUNCATED)

Spectrum of reperfusion strategies and factors influencing the use of primary angioplasty in patients with acute myocardial infarction admitted to hospitals with the facilities to perform primary angioplasty. Maximal Individual Therapy in Acute Myocardial Infarction (MITRA) Study Group

OBJECTIVE

To determine the frequency of the use of primary angioplasty in patients with acute myocardial infarction and the factors influencing its indications in hospitals with the facilities to perform this treatment.

DESIGN

Data from the maximal individual therapy in acute myocardial infarction (MITRA) trial were analysed, concerning the effects of the decisions of individual hospitals, the time of admission of patients, and the effects of patient characteristics on the selection of reperfusion treatment.

PATIENTS

Between June 1994 and January 1997 eight hospitals treated 1532 patients with acute myocardial infarction. 418 (27.3%) were treated conservatively, 641 (41.8%) were treated using intravenous thrombolysis, 387 (25.3%) were treated using primary angioplasty, and 86 (5.6%) received a combination of thrombolysis and angioplasty.

RESULTS

The proportion of patients treated with primary angioplasty varied from 1.8% to 57.7% among the eight hospitals. The use of primary angioplasty during non-office hours also showed wide variation, ranging from 20% to 54% between centres. The use of thrombolysis was comparatively evenly distributed during the non-office hours, ranging from 50-69%. Four hospitals with a primary angioplasty use rate > 30% showed no difference in the proportion of patients with contraindications for thrombolysis, high risk patients, or a combination of both, when compared with four hospitals with a lower rate of primary angioplasty use (98/322 (30.4%) v 19/65 (29. 2%), respectively, p = 0.847).

CONCLUSIONS

In hospitals with the facilities for performing primary angioplasty the most important factors influencing its use were the discretion of the individual hospital and the time of patient admission. Characteristics of patients did not influence the choice of reperfusion treatment

Early revascularization in acute myocardial infarction complicated by cardiogenic shock. SHOCK Investigators. Should We Emergently Revascularize Occluded Coronaries for Cardiogenic Shock

BACKGROUND

The leading cause of death in patients hospitalized for acute myocardial infarction is cardiogenic shock. We conducted a randomized trial to evaluate early revascularization in patients with cardiogenic shock.

METHODS

Patients with shock due to left ventricular failure complicating myocardial infarction were randomly assigned to emergency revascularization (152 patients) or initial medical stabilization (150 patients). Revascularization was accomplished by either coronary-artery bypass grafting or angioplasty. Intraaortic balloon counterpulsation was performed in 86 percent of the patients in both groups. The primary end point was mortality from all causes at 30 days. Six-month survival was a secondary end point.

RESULTS

The mean age of the patients was 66+/-10 years, 32 percent were women and 55 percent were transferred from other hospitals. The median time to the onset of shock was 5.6 hours after infarction, and most infarcts were anterior in location. Ninety-seven percent of the patients assigned to revascularization underwent early coronary angiography, and 87 percent underwent revascularization; only 2.7 percent of the patients assigned to medical therapy crossed over to early revascularization without clinical indication. Overall mortality at 30 days did not differ significantly between the revascularization and medical-therapy groups (46.7 percent and 56.0 percent, respectively; difference, -9.3 percent; 95 percent confidence interval for the difference, -20.5 to 1.9 percent; P=0.11). Six-month mortality was lower in the revascularization group than in the medical-therapy group (50.3 percent vs. 63.1 percent, P=0.027).

CONCLUSIONS

In patients with cardiogenic shock, emergency revascularization did not significantly reduce overall mortality at 30 days. However, after six months there was a significant survival benefit. Early revascularization should be strongly considered for patients with acute myocardial infarction complicated by cardiogenic shock.

[Therapy of acute myocardial infarct--primary PTCA or thrombolysis?]

Since reperfusion of the infarct-related coronary artery has been established as a mainstay in the treatment of acute myocardial infarction (AMI) mechanical recanalization by direct angioplasty has been used as an alternative to the standard treatment with thrombolysis. Direct PTCA is more efficient than thrombolysis in terms of reperfusion rates, whereas thrombolysis is more readily available. Thrombolysis reduces mortality from AMI by approximately 25%. The clinical efficacy is strongly time-dependent, and treatment within the first hour of AMI improves survival by nearly 50% by preventing transmural infarction in a significant proportion of the patients. The disadvantage of thrombolysis is its limited efficacy in terms of rapid, complete and sustained patency of the infarct vessel yielding optimal results in only 50% of the patients. Direct PTCA is generally agreed to be more efficient to recanalize the infarct vessel, but its clinical advantage remains controversial. The first randomized studies of direct PTCA in AMI from highly specialized centers in selected patients reported success rates of coronary reperfusion up to 97% resulting in a trend to less death and reinfarction, but the differences were significant only in a metaanalysis of these small studies. The real world of direct PTCA has been depicted by a large registry in Germany of the Arbeitsgemeinschaft Leitender Kardiologischer Krankenhausärzte (ALKK) now including more than 4,000 direct PTCA-procedures since 1994. In this registry, the success rate of direct PTCA was 87% as defined by a final TIMI-grade 3 perfusion of the infarct vessel which is close to the data of the MITI-registry and the GUSTO IIb study. Failed PTCA was associated with an exceptionally high mortality rate of 36% confirming earlier observational reports. The non-randomized comparison of thrombolysis and direct PTCA in the MITI-registry showed no differene in survival or reinfarction rates, and the randomized GUSTO IIb substudy of direct PTCA versus front-loaded alteplase showed a small advantage in death and reinfarction rates at 30 days which dissipated over time leaving no significant clinical advantage of direct PTCA over thrombolysis at 6 months. Thus, in myocardial infarction in general the advantage of direct PTCA over thrombolysis is at best minimal. The reason is very probably the longer time lag until the procedure is started, the lower success rate as compared to the first reports of some specialized centers, and the clearly negative impact of failed PTCA on survival. Moreover, the immediate success of direct PTCA seems to be overestimated by the operator as demonstrated by comparison of central and local estimates of the TIMI flow rates in GUSTO IIb. Improvements of direct PTCA in AMI might be possible by coronary stenting which has markedly increased to more than 60% during the last year in the ALKK-registry. This was accompanied by a slight decrease in death and reinfarction rates. Further improvements can be expected from GP IIb/IIIa platelet antagonists which are under clinical investigation. It has been claimed, that in cardiogenic shock direct PTCA is more effective than thrombolysis. This hypothesis is based on comparison of failed versus successful PTCA-attempts, but this comparison is not valid since failed procedures clearly increase mortality. In the GUSTO-1 study patients with cardiogenic shock had lower mortality with than without an early coronary angiogram. This survival advantage, however, was independent of revascularization since only half of the patients with an early angiogram had PTCA. The same was observed in the International Shock Registry, reflecting significant selection bias in that patients in relatively better condition will be taken to the cathlab whereas apparently hopeless cases will not. In the ALKK-registry half of the patients in cardiogenic shock died after direct PTCA casting doubt on the presumed high clinical efficacy of this strategy. (ABST

Reperfusion therapy in cardiogenic shock complicating acute myocardial infarction

The most frequent cause of cardiogenic shock complicating acute myocardial infarction is extensive myocardial damage involving a relevant amount of myocardium. Treatment is aimed at support for the circulation with the use of drugs and mechanical devices and at restoration of perfusion to the ischemic myocardium as soon as possible. Therefore, emergency coronary angiography is indicated in all patients. Coronary angioplasty is the first option in patients with suitable anatomy because it is the fastest available technique able to recanalize the infarct-related vessel. Stenting of the infarct artery must be considered because stent implantation has been shown to improve results in comparison with the balloon alone. Complete revascularization is likely to offer a better outcome in patients with multivessel disease. Coronary surgery is indicated as first-line intervention in patients who have a coronary anatomy not suitable for angioplasty; it may also serve to complete revascularization in patients with multivessel disease initially treated with emergency coronary angioplasty. In a hospital without facilities for emergency coronary interventions, mechanical circulatory support with an intra-aortic balloon pump should be instituted and thrombolysis started; then patients should be transferred immediately to a tertiary center to undergo coronary angiography and revascularization procedures, if needed. In patients not benefiting from this aggressive revascularization strategy who develop irreversible extensive myocardial damage, heart transplantation must be considered.

Long-term (three-year) prognosis of patients treated with reperfusion or conservatively after acute myocardial infarction. Israeli Thrombolytic Survey Group

OBJECTIVES

This survey sought to assess the frequency of the use of thrombolytic therapy, invasive coronary procedures (ICP) (angiography, percutaneous transluminal coronary angioplasty and coronary artery bypass grafting [CABG]), variables associated with their use, and their impact on early (30-day) and long-term (3-year) mortality after acute myocardial infarction (AMI).

BACKGROUND

Few data are available regarding the implementation in daily practice of the results of clinical trials of treatments for AMI and their impact on early and long-term prognosis in unselected patients after AMI.

METHODS

A prospective community-based national survey was conducted during January-February 1994 in all 25 coronary care units operating in Israel.

RESULTS

Among 999 consecutive patients with an AMI (72% men; mean age 63+/-12 years) acute reperfusion therapy (ART) was used in 455 patients (46%; thrombolysis in 435 patients [44%] and primary angioplasty in 20 [2%]). Its use was independently associated with anterior AMI location and hospitals with on-site angioplasty facilities, whereas advancing age, prior myocardial infarction (MI) and prior angioplasty or CABG were independently associated with its lower use. The three-year mortality of patients treated with ART was lower than in counterpart patients (22.0% vs. 31.4%, p = 0.0008), mainly as the result of 30-day to 3-year outcome (12.4% vs. 21.1%; hazard ratio = 0.73, 95% confidence interval [CI] 0.52 to 1.03). Independent predictors of long-term mortality were: age, heart failure on admission or during the hospitalization, ventricular tachycardia or fibrillation and diabetes. The outcome of patients not treated with ART differed according to the reason for the exclusion, where patients with contraindications experienced the highest three-year (50%) mortality rate. After ART, coronary angiography, angioplasty and CABG were performed in-hospital in 28%, 12% and 5% of patients, respectively. Their use was independently associated with recurrent infarction or ischemia, on-site catheterization or CABG facilities, non-Q-wave AMI and anterior infarct location. In the entire study population, and in patients with a non-Q-wave AMI, performance of ICP was associated with lower 30-day mortality (odds ratio [OR] = 0.53, 95% CI 0.25 to 0.98, and OR = 0.21, 0.03 to 0.84, respectively), but not thereafter.

CONCLUSIONS

This survey demonstrates the extent of implementation in daily practice of ART and ICP and their impact on early and long-term prognosis in an unselected population after AMI.

Cardiogenic shock complicating acute myocardial infarction: predictors of death. GUSTO Investigators. Global Utilization of Streptokinase and Tissue-Plasminogen Activator for Occluded Coronary Arteries

BACKGROUND

Current knowledge of predictors of death among patients with cardiogenic shock complicating myocardial infarction is limited. We aimed to develop a risk assessment prognostic algorithm of 30-day mortality, including clinical and hemodynamic data prospectively collected among patients with cardiogenic shock in the 41,021-patient Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries (GUSTO-I) trial.

METHODS

We used logistic regression modeling techniques to evaluate the relations between demographic, clinical, and hemodynamic characteristics and 30-day mortality rate for the entire shock population (n = 2968) and for patients who underwent right-heart catheterization (n = 995).

RESULTS

The odds (95% confidence interval) of dying were 1.49 times higher (1.27-1.74) for patients 10 years older and 1.70 times higher (1.19-2.44) for patients with prior infarction. Findings derived from physical examination, such as altered sensorium and cold, clammy skin, were important independent predictors of prognosis (odds of dying 1.68 times higher for each [1.19-2.39 and 1.15-2.46]). The odds of dying were also 2.25 times higher (1.61-3.15) in patients with oliguria. Mortality rate was lowest for cardiac output and pulmonary capillary wedge measurements of 5.1 L/min and 20 mm Hg, respectively, and increased with either higher or lower values. Patients with shock had better outcomes than patients in whom shock developed later, although for the latter subgroup, prognosis was worse in patients who had heart failure (Killip class II to III).

CONCLUSIONS

We devised a prognostic algorithm for patients with cardiogenic shock complicating acute myocardial infarction. In addition to demographic and easily derived physical examination features, data derived from right-heart catheterization added valuable information that increased the ability to predict outcome in this high-risk population.

Primary percutaneous transluminal coronary angioplasty for acute myocardial infarction in patients not included in randomized studies. Maximal Individual Therapy in Acute Myocardial Infarction (MITRA) Study Group

Patients with acute myocardial infarction included in randomized trials comparing primary percutaneous transluminal coronary angioplasty (pPTCA) with thrombolysis represent a special subgroup of patients with a low event rate. Patients excluded from these trials represent a variety of different subgroups, with different patient characteristics and possibly different clinical event rates. Primary PTCA was performed in 491 consecutive patients with acute myocardial infarction in the prospective multicenter observational Maximal Individual Therapy in Acute Myocardial Infarction trial. They were divided into the following groups: group I, patients fulfilling the inclusion criteria of the randomized trials (284 of 491, 58%); group II, patients not included in these trials (207 of 491, 42%). Of group II the following subgroups were defined: group IIa, patients in cardiogenic shock (20 of 491, 4.1%); group IIb, patients with a left bundle branch block (12 of 491, 2,4%); group IIc, patients with contraindications for thrombolysis (42 of 491, 8.6%); group IId, patients with a nondiagnostic first electrocardiogram (95 of 491, 19.3%); group IIe, patients with a prehospital delay of > 12 hours (72 of 491, 14.7%); group IIf, patients with an unknown prehospital delay (30 of 491, 6.1%). A comparison of groups I and II showed similar baseline characteristics but a higher clinical event rate during hospitalization was seen in group II: combined end point of death, reinfarction, heart failure equal to or greater than NYHA class III, any stroke or postinfarction angina, 26.6% versus 18%; p = 0.022. Hospital deaths were nearly twice as high in these patients, without reaching statistical significance (10.6% vs 6%; p = 0.06). The subgroups of group II showed quite different rates of clinical events. In-hospital death rates were: IIa, 40% (8 of 20); IIb, 8% (1 of 12); IIc, 12% (5 of 42); IId, 5% (5 of 95); IIe, 6% (4 of 72); and IIf, 13% (4 of 30). The incidence of the combined end point was 60% (12 of 20) in IIa, 33% (4 of 12) in IIb, 29% (12 of 42) in IIc, 16% (15 of 95) in IId, 26% (19 of 72) in IIe, and 33% (10 of 30) in IIf. Thus, in clinical practice, about half of the patients treated with pPTCA would not have been included in randomized trials comparing pPTCA with thrombolysis. These patients represent a population at higher risk for in hospital clinical events. However, they do represent very different nonhomogenous subgroups with different clinical event rates.

Temporal trends in cardiogenic shock complicating acute myocardial infarction

BACKGROUND

Limited information is available on trends in the incidence of and mortality due to cardiogenic shock complicating acute myocardial infarction. We studied the incidence of cardiogenic shock complicating acute myocardial infarction and in-hospital death rates among patients with this condition in a single community from 1975 through 1997.

METHODS

We conducted an observational study of 9076 residents of metropolitan Worcester, Massachusetts, who were hospitalized with confirmed acute myocardial infarction in all local hospitals during 11 one-year periods between 1975 and 1997. Our study included periods before and after the advent of reperfusion therapy.

RESULTS

The incidence of cardiogenic shock remained relatively stable over time, averaging 7.1 percent among patients with acute myocardial infarction. The results of a multivariable regression analysis indicated that the patients hospitalized during recent study years were not at a substantially lower risk for shock than patients hospitalized in the mid-to-late 1970s. Patients in whom cardiogenic shock developed had a significantly greater risk of dying during hospitalization (71.7 percent) than those who did not have cardiogenic shock (12.0 percent, P<0.001). A significant trend toward an increase in in-hospital survival among patients with cardiogenic shock in the mid-to-late 1990s was found in crude and adjusted analyses.

CONCLUSIONS

Our findings indicate no significant change in the incidence of cardiogenic shock complicating acute myocardial infarction over a 23-year period. However, the short-term survival rate has increased in recent years at the same time as the use of coronary reperfusion strategies has increased.

Efficacy of invasive strategy for the management of acute myocardial infarction complicated by cardiogenic shock

This retrospective study evaluates the influence of an invasive strategy of urgent coronary revascularization on the in-hospital mortality of patients with acute myocardial infarction (AMI) complicated early by cardiogenic shock. Among 1,981 patients with AMI admitted to our institution from 1994 to 1997, 162 patients (8.2%) developed cardiogenic shock unrelated to mechanical complications. The strategy of management was considered invasive if an urgent coronary angiography was indicated within 24 hours of symptom onset. Every other strategy was considered conservative. Fifty-seven patients who developed the shock late or after a revascularization procedure, or who died on admission, were excluded. The strategy was invasive in 73 patients (70%). Five of them died before angiography could be performed and 65 underwent angioplasty (success rate 72%). By univariate analysis the invasive strategy was associated with a lower mortality than conservative strategy (71% vs 91%, p = 0.03), but this association disappeared after adjustment for baseline characteristics. Older age, nonsmoking, and previous ischemic heart disease were independent predictors of mortality. In conclusion, we have failed to demonstrate that a strategy of urgent coronary revascularization within 24 hours of symptom onset for patients with AMI complicated by cardiogenic shock is independently associated with a lower in-hospital mortality. This strategy was limited by the high mortality within 1 hour of admission in patients with cardiogenic shock, the modest success rate of angioplasty in this setting, and the powerful influence of some adverse baseline characteristics on prognosis.

Primary angioplasty for the treatment of acute myocardial infarction: experience at two community hospitals without cardiac surgery

OBJECTIVES

We sought to establish the safety and efficacy of primary percutaneous transluminal coronary angioplasty in patients with acute myocardial infarction (AMI) at two community hospitals without on-site cardiac surgery.

BACKGROUND

Though randomized studies indicate that primary angioplasty in AMI may result in superior outcomes compared with fibrinolytic therapy, the performance of primary angioplasty at hospitals without cardiac surgery is debated.

METHODS

Three experienced operators performed 506 consecutive immediate coronary angiograms with primary angioplasty when appropriate in patients with suspected AMI at two community hospitals without cardiac surgery, following established rigorous program criteria.

RESULTS

Clinical high risk predictors (Killip class 3 or 4, age > or = 75 years, anterior AMI, out-of-hospital ventricular fibrillation) and/or angiographic high risk predictors (left main or three-vessel disease or ejection fraction <45%) were present in 69.6%. Angioplasty was performed in 66.2%, with a median time from emergency department presentation to first angiogram of 94 min and a procedural success rate of 94.3%. The in-hospital mortality for the entire study population was 5.3%. Of those without initial cardiogenic shock, the in-hospital mortality was 3.0%. Of 300 patients who were discharged after primary angioplasty, only four died within the first 6 months, with 97.7% follow-up. No patient died or needed emergent aortocoronary bypass surgery because of new myocardial jeopardy caused by a complication of the cardiac catheterization or angioplasty procedure.

CONCLUSIONS

Immediate coronary angiography with primary angioplasty when appropriate in patients with AMI can be performed safely and effectively in community hospitals without on-site cardiac surgery when rigorous program criteria are established.

Echocardiographic Assessment of Complications Related to Left Ventricular Function in Acute Myocardial Infarction

Three complications of acute myocardial infarction without myocardial rupture are directly associated to the function of the myocardium: papillary muscle dysfunction, congestive heart failure, and cardiogenic shock. In this article, the pathophysiological mechanism of each complication is discussed, and the contribution of echocardiography to diagnosis and management is reviewed.

Differences in patients with acute myocardial infarction treated with primary angioplasty or thrombolytic therapy. Maximal Individual Therapy in Acute Myocardial Infarction (MITRA) Study Group

BACKGROUND

Little is known about the differences in patients with acute myocardial infarction (AMI) treated with primary angioplasty or intravenous thrombolysis in clinical practice.

METHODS

In all, 5,906 patients with AMI were registered by the Maximal Individual Therapy in Acute Myocardial Infarction (MITRA) study. Of these, 491 (8.3%) patients were treated with primary angioplasty and 2,817 (47.7%) with intravenous thrombolysis.

RESULTS

There were only minor differences in baseline characteristics between the two groups. Prehospital delay time (median) was longer in the angioplasty group than in the thrombolysis group (161 vs. 120, p = 0.001), as was door-to-treatment time (88 vs. 30 min; p = 0.001). Patients treated with primary angioplasty more often had contraindications for thrombolytic therapy (12.9 vs. 6%, p = 0.001) and received beta blockers (65 vs. 58.1%, p = 0.004), heparin (98.2 vs. 91.6%, p = 0.001), angiotensin-converting enzyme (ACE) inhibitors (64.8 vs. 50%, p = 0.001) and "optimal" concomitant medication (56.4 vs. 42.9%, p = 0.001) more often. Univariate analysis showed a significant lower incidence of heart failure (5.3 vs. 16.5%, p = 0.001), postinfarct angina (7.3 vs. 16.4%, p = 0.001), in-hospital death (7.9 vs. 11.7%, p = 0.015) and the combined end point (21.6 vs. 40.3%, p = 0.001) in these patients. Stepwise logistic regression analysis revealed optimal concomitant medication [odds ratio (OR) = 0.94, 95% confidence interval (CI): 0.89-0.98) and the type of revascularization (OR = 0.65, 95% CI: 0.58-0.73) to be associated with a significant reduction in the incidence of the combined end point. Similar results were obtained in all predefined subgroups.

CONCLUSIONS

In clinical practice, patients treated with primary angioplasty are more often treated with beta blockers and ACE inhibitors than patients treated with intravenous thrombolysis. Thus, the selection of patients and the type of revascularization contributes to the reduction in mortality, overt heart failure, and postinfarct angina in these patients.

Comparison of primary angioplasty with conservative therapy in patients with acute myocardial infarction and contraindications for thrombolytic therapy. Maximal Individual Therapy in Acute Myocardial Infarction (MITRA) Study Group

The benefit of primary angioplasty in patients with acute myocardial infarction (AMI) and contraindications for thrombolysis compared to a conservative regimen is still unclear. Out of 5,869 patients with AMI registered by the MITRA trial, 337 (5.7%) patients had at least one strong contraindication for thrombolytic therapy. Out of these 337 patients 46 (13.6%) were treated with primary angioplasty and 276 (86.4%) were treated conservatively. Patients treated conservatively were older (70 years vs. 60 years; P=0.001), had a higher rate of a history with chronic heart failure (14.8% vs. 4.4%; P=0.053), a higher heart rate at admission (86 beats/min vs. 74 beats/min; P=0.001), and a higher prevalence of diabetes mellitus (27.1% vs. 12.8%; P=0.056). Patients treated with primary angioplasty received more often aspirin (91.3% vs. 74.6%; P=0.012), beta-blockers (60.9% vs. 46.1%; P = 0.062), angiotensin converting enzyme (ACE) inhibitors (71.7% vs. 44%; P=0.001), and the so-called optimal adjunctive medication (54.4% vs. 32.3%; P=0.004). Hospital mortality was significantly lower in patients who received primary angioplasty (univariate: 2.2% vs. 24.7%; P=0.001; multivariate: OR=0.46; P=0.0230). In patients with AMI and contraindications for thrombolytic therapy, primary angioplasty was associated with a significantly lower mortality compared to conservative treatment. Therefore, hospitals without the facilities to perform primary angioplasty should try to refer such patients to centers with the facilities for such a service, if this is possible in an acceptable time.

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.

Cardiac rehabilitation in older coronary patients

The majority of patients presenting with acute coronary disease or undergoing coronary revascularization procedures are older than age 65. Disability rates are very high in these patient populations, particularly in women, the older-old, and patients with clinical manifestations of angina pectoris or chronic heart failure. The presence of mental depression is also an important determinant of poor physical functioning. Cardiac rehabilitation has been demonstrated to safely increase aerobic capacity, muscular strength, and endurance in older coronary populations.

Benefits, risks and alternatives of pulmonary artery catheterization

Twenty-five years after the introduction of the pulmonary artery catheter in clinical practice, its effectiveness in improving patient outcome is seriously questioned. Experts still recommend to use pulmonary artery catheters in selected critically ill patients, although evidence supporting these recommendations is lacking. The risks and the unclear benefits associated with this procedure should prompt the search for alternative, noninvasive monitoring techniques.

The use of intraaortic balloon counterpulsation as an adjunct to reperfusion therapy in cardiogenic shock

Modern coronary care unit interventions have not reduced the high mortality rate associated with cardiogenic shock due to acute myocardial infarction. Results with thrombolytic therapy have also been disappointing because of poor infarct artery patency rates in a low coronary flow state. Percutaneous transluminal coronary angioplasty appears to be a beneficial intervention, but the technique is not available at most hospitals. Intraaortic balloon counterpulsation provides temporary hemodynamic and clinical improvement in the majority of patients with cardiogenic shock. The use of intraaortic counterpulsation to augment patency rates with thrombolytic therapy or to stabilize patients for transfer to a hospital with angioplasty services appears to be a promising strategy for hospitals without an interventional cardiac catheterization laboratory.

Early assessment and in-hospital management of patients with acute myocardial infarction at increased risk for adverse outcomes: a nationwide perspective of current clinical practice. The National Registry of Myocardial Infarction (NRMI-2) Participants

BACKGROUND

Therapeutic decision making in critically ill patients requires both prompt and comprehensive analysis of available information. Data derived from randomized clinical trials provide a powerful tool for risk assessment in the setting of acute myocardial infarction (MI); however, timely and appropriate use of existing therapies and resources are the key determinants of outcome among high-risk patients.

METHODS

Demographic, procedural, and outcome data from patients with MI were collected at 1073 U.S. hospitals collaborating in the National Registry of MI (NRMI 2). Patients were classified on hospital arrival as either "low risk" or "high risk" according to a modified Thrombolysis in Myocardial Infarction II Risk Scale based on predetermined demographic, electrocardiographic, and clinical features.

RESULTS

Among the 170,143 patients enrolled, 115,222 (67.5%) were classified as low risk and 55,521 (32.5%) as high risk for in-hospital death, recurrent ischemia, recurrent MI, congestive heart failure, and stroke. Using a composite unsatisfactory outcome measure, in-hospital adverse events were had by a greater proportion of patients initially classified as high risk compared with those classified as low risk. By multivariate analysis, age >70 years, prior MI, Killip class >1, anterior site of infarction, and the combination of hypotension and tachycardia were independent predictions of poor outcome in patients with or without ST-segment elevation on the presenting electrocardiogram. High-risk patients with ST-segment elevation were treated with thrombolytics (47.5%) or alternative forms of reperfusion therapy (9.3%) within 62 minutes and 226 minutes of hospital arrival, respectively. High-risk patients offered reperfusion therapy were also more likely to receive aspirin, beta-blockers (intravenous, oral) and angiotensin-converting enzyme inhibitors within 24 hours of infarction (all p < 0.0001), survive their event (8.4% versus 21.4% p < 0.0001), and leave the hospital sooner than those not reperfused.

CONCLUSIONS

This large registry experience included more than 150,000 nonselected patients with MI and suggests that high-risk patients can be identified on initial hospital presentation. The current use of reperfusion and adjunctive therapies among high-risk patients is suboptimal and may directly influence outcome. Randomized trials designed to test the impact of specific management strategies on outcome according to initial risk classification are warranted.

Systematic direct angioplasty and stent-supported direct angioplasty therapy for cardiogenic shock complicating acute myocardial infarction: in-hospital and long-term survival

OBJECTIVES

This prospective observational study was conducted to examine the apparent impact of a systematic direct percutaneous transluminal coronary angioplasty (PTCA) strategy on mortality in a series of 66 consecutive patients with acute myocardial infarction (AMI) complicated by cardiogenic shock, and to analyze the predictors of outcome after successful direct PTCA.

BACKGROUND

Previous studies have reported encouraging results with PTCA in patients with AMI complicated by cardiogenic shock, but a biased case selection for PTCA may have heavily influenced the observed outcomes.

METHODS

All patients admitted with AMI were considered eligible for direct PTCA, including those with the most profound shock, and no upper age limit was used. The treatment protocol also included stenting of the infarct-related artery for a poor or suboptimal angiographic result after conventional PTCA.

RESULTS

Between January 1995 and March 1997, 364 consecutive patients underwent direct PTCA, and in 66 patients AMI was complicated by cardiogenic shock. In patients with cardiogenic shock, direct PTCA had a success rate of 94%; an optimal angiographic result was achieved in 85%; primary stenting of the infarct-related artery was accomplished in 47%; and the in-hospital mortality rate was 26%. Univariate analysis showed that patient age, chronic coronary occlusion and completeness of revascularization were significantly related to in-hospital mortality. The mean follow-up period was 16 +/- 8 months. Survival rate at 6 months was 71%. Comparison of event-free survival in patients with a stented or nonstented infarct-related artery suggests an initial and long-term benefit of primary stenting.

CONCLUSIONS

Systematic direct PTCA, including stent-supported PTCA, can establish a Thrombolysis in Myocardial Infarction (TIMI) grade 3 flow in the great majority of patients presenting with AMI and early cardiogenic shock. High performance criteria, including new devices such as coronary stents, should be considered in randomized trials where mechanical revascularization therapy is being tested.