Percutaneous transluminal coronary angioplasty improves survival in acute myocardial infarction complicated by cardiogenic shock

Contemporary reperfusion therapy for cardiogenic shock: the GUSTO-I trial experience. The GUSTO-I Investigators. Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries

OBJECTIVES

This study sought to examine the incidence, temporal profile and clinical implications of shock in a large trial of thrombolytic therapy for acute myocardial infarction.

BACKGROUND

Despite advances in the treatment of acute ischemic syndromes, cardiogenic shock remains associated with significant morbidity and mortality.

METHODS

Patients who presented within 6 h of symptom onset were randomized to four treatment strategies: 1) streptokinase plus subcutaneous heparin; 2) streptokinase plus intravenous heparin; 3) accelerated recombinant tissue-type plasminogen activator (rt-PA) plus intravenous heparin; or 4) streptokinase and rt-PA plus intravenous heparin. The primary end point was 30-day all-cause mortality.

RESULTS

Shock occurred in 2,972 patients (7.2%): 315 (11%) had shock on arrival, and 2,657 (89%) developed shock after hospital admission. Reinfarction occurred in 11% of patients who developed shock compared with 3% of patients without shock. The mortality rate was significantly higher in patients who presented with (57%) or developed (55%) shock than in those without shock (3%) (p < 0.001). Shock developed significantly less frequently in patients receiving rt-PA. There were fewer deaths in patients who presented with shock and were treated with streptokinase plus intravenous heparin or who developed shock and were treated with streptokinase plus subcutaneous heparin. Patients who developed shock had a significantly lower 30-day mortality rate if angioplasty was performed.

CONCLUSIONS

Because cardiogenic shock occurred most often after admission and with recurrent ischemia and reinfarction, recognizing signs of incipient shock may improve outcome. Fewer patients treated with rt-PA developed shock, yet those developing shock had the same high mortality rate as those presenting with shock, regardless of treatment. Only angioplasty was associated with a significantly lower mortality rate.

Identification and treatment of complications of myocardial infarction

Mechanical complications of acute myocardial infarction include papillary muscle rupture with severe mitral regurgitation, ventricular septal rupture with acute ventricular septal defect, acute and subacute free-wall rupture, and hemodynamically significant right ventricular infarction. Although such complications are infrequent, their importance is underscored because of the potential ability to correct them with early diagnosis and appropriate treatment. The diagnosis necessitates a high degree of suspicion based on clinical clues and rapid diagnostic testing. Beside two-dimensional echocardiography, sometimes with transesophageal echocardiography, is most commonly used to diagnose or exclude these complications. Patients suspected of having a mechanical complication of myocardial infarction should be urgently transferred to a medical center experienced in the management of these problems. For deteriorating patients without identifiable mechanical complications, coronary angiography and reperfusion with direct angioplasty should be considered.

The role of angioplasty in acute myocardial infarction

The role of percutaneous transluminal coronary angioplasty (PTCA) in the management of acute myocardial infarction (AMI) has not yet been precisely defined. The longest experience with PTCA in this setting has been in patients who are not candidates for thrombolytic therapy and in patients in whom thrombolysis has failed. Clinical interest has recently focused on direct use of PTCA (instead of thrombolysis) as the initial approach to reperfusion in AMI. We review the conceptual bases for both thrombolytic therapy and PTCA in AMI, and we then detail the clinical experience with PTCA in a variety of patient populations with AMI to guide use of both therapies in this setting.

Comparison of front-loaded recombinant tissue-type plasminogen activator, anistreplase and combination thrombolytic therapy for acute myocardial infarction: results of the Thrombolysis in Myocardial Infarction (TIMI) 4 trial

OBJECTIVES

The aim of our study was to determine a superior thrombolytic regimen from three: anistreplase (APSAC), front-loaded recombinant tissue-type plasminogen activator (rt-PA) or combination thrombolytic therapy.

BACKGROUND

Although thrombolytic therapy has been shown to reduce mortality and morbidity after acute myocardial infarction, it has not been clear whether more aggressive thrombolytic-antithrombotic regimens could improve the outcome achieved with standard regimens.

METHODS

To address this issue, 382 patients with acute myocardial infarction were randomized to receive in a double-blind fashion (along with intravenous heparin and aspirin) APSAC, front-loaded rt-PA or a combination of both agents. The primary end point "unsatisfactory outcome" was a composite clinical end point assessed through hospital discharge.

RESULTS

Patency of the infarct-related artery (Thrombolysis in Myocardial Infarction [TIMI] grade 2 or 3 flow) at 60 min after the start of thrombolysis was significantly higher in rt-PA-treated patients (77.8% vs. 59.5% for APSAC-treated patients and 59.3% for combination-treated patients [rt-PA vs. APSAC, p = 0.02; rt-PA vs. combination, p = 0.03]). At 90 min, the incidence of both infarct-related artery patency and TIMI grade 3 flow was significantly higher in rt-PA-treated patients (60.2% had TIMI grade 3 flow vs. 42.9% and 44.8% of APSAC- and combination-treated patients, respectively [rt-PA vs. APSAC, p < 0.01; rt-PA vs. combination, p = 0.02]). The incidence of unsatisfactory outcome was 41.3% for rt-PA compared with 49% for APSAC and 53.6% for the combination (rt-PA vs. APSAC, p = 0.19; rt-PA vs. combination, p = 0.06). The mortality rate at 6 weeks was lowest in the rt-PA-treated patients (2.2% vs. 8.8% for APSAC and 7.2% for combination thrombolytic therapy [rt-PA vs. APSAC, p = 0.02; rt-PA vs. combination, p = 0.06]).

CONCLUSIONS

Front-loaded rt-PA achieved significantly higher rates of early reperfusion and was associated with trends toward better overall clinical benefit and survival than those achieved with a standard thrombolytic agent or combination thrombolytic therapy. These findings support the concept that more rapid reperfusion of the infarct-related artery is associated with improved clinical outcome.

Coronary angioplasty in the patient with acute myocardial infarction

In patients with acute myocardial infarction, percutaneous transluminal coronary angioplasty (PTCA) may be used (1) to restore antegrade flow in the infarct artery (so called "primary" PTCA) instead of thrombolytic therapy, (2) to establish antegrade coronary flow after unsuccessful thrombolytic therapy (so called "rescue" or "salvage" PTCA), and (3) to reduce the residual infarct artery stenosis after successful thrombolysis. This review examines the prospective, randomized studies that have addressed the use of PTCA for each of these purposes. In selected circumstances, PTCA is a reasonable alternative to thrombolytic therapy in patients with evolving or recent Q-wave myocardial infarction. In those patients with acute myocardial infarction complicated by cardiogenic shock, PTCA may be the preferred treatment. After thrombolytic therapy, the use of PTCA in the absence of spontaneous or provocable ischemia offers no benefit with regard to left ventricular function or survival. In this circumstance, its use is associated with an excessive risk of bleeding, transfusions, and emergent coronary artery bypass surgery when performed within hours of infarction.

Treatment strategies for acute myocardial infarction complicated by cardiogenic shock in a community hospital

The risk and benefits of three treatment strategies were examined in 64 consecutive patients with acute myocardial infarction and cardiogenic shock. Thirteen patients received thrombolytic therapy (group 1), 29 patients received intra-aortic balloon pump counterpulsation support (group 2), and 22 patients were treated with combined thrombolytic therapy and intra-aortic balloon pump counterpulsation support (group 3). The groups were similar in regard to age, sex, medical history, hemodynamic data, and extent of coronary artery disease. Survival was improved in patients treated with combined thrombolytic therapy and intra-aortic balloon pump counterpulsation support (group 1, 23 percent; group 2, 28 percent; and group 3, 68 percent; p = 0.0049). Seven percent of the patients who remained at the community hospital survived vs 69 percent who were transferred to a tertiary care center (p < 0.001), and 17 percent survived who were treated medically vs 71 percent who received revascularization (p < 0.001). These findings suggest that patients who present to a community hospital in cardiogenic shock can have their conditions stabilized, and they can then be transferred to a tertiary care hospital for revascularization and have the same outcome as patients who initially present to tertiary care hospitals.

Left ventricular assist without thoracotomy: clinical experience with the Dennis method

A method to provide left ventricular circulatory assistance without thoracotomy was developed and implemented in 2 patients. The left atrium is cannulated from the neck by passing a catheter across the interatrial septum (Dennis technique) using fluoroscopic and echocardiographic imaging. To facilitate ambulation, the arterial catheter is connected to the right axillary artery. Left atrial to axillary arterial flow is produced by a centrifugal pump. Two patients were perfused at 2.7 to 3.5 L/min for 5 and 6.5 days. One patient had successful coronary angioplasty during perfusion and remains alive 1 year later. The other patient died of sepsis and anuria that preceded implementation of circulatory assistance. The Dennis method of continuous left ventricular circulatory assistance avoids thoracotomy, requires a minimal operation, is portable and inexpensive, uses widely available equipment, and is particularly suitable for patients in cardiogenic shock after acute myocardial infarction. The method is safe and cost-effective, and merits wider application in selected patients.

Primary angioplasty for acute myocardial infarction in 1,000 consecutive patients. Results in an unselected population and high-risk subgroups

Primary angioplasty (direct angioplasty without antecedent thrombolytic therapy) has remained an exclusive and consistent method of infarct intervention at our institution over the past 13 years. A total of 1,000 consecutive patients were prospectively enrolled in our primary angioplasty database. Of patients presenting to our group with an acute myocardial infarction, 96% of those eligible received immediate angioplasty. Cardiogenic shock was noted in 79 patients (7.9%). The mean time from pain onset to reperfusion was 5.4 +/- 4.0 hours. Infarct-vessel recanalization was accomplished in 94% of patients. Recanalization rates were similar among the 3 native epicardial coronary systems but were lower in bypass grafts (86%; p < 0.0001). Overall in-hospital mortality was 7.8%; mortality with cardiogenic shock was 44%. Global ejection fraction increased from 49.7% preangioplasty to 57.4% at the time of dismissal. The amount of myocardial salvage was highly dependent on the size of the initial infarction (the largest infarctions benefiting the most). Patients reperfused in < 2 hours experienced a very low mortality (4%) and impressive myocardial salvage. Complications included stroke in 0.5%, significant bleeding in 2.8%, and early reocclusion of the infarct vessel in 13%. Primary angioplasty is broadly applicable to patients presenting with acute myocardial infarction and results in a very high rate of infarct vessel recanalization, with a mortality rate of 7.8%. This strategy may be uniquely effective in patients presenting with cardiogenic shock, large infarctions, contraindications to thrombolytic therapy, and prior bypass surgery.

Late outcome after percutaneous transluminal coronary angioplasty during acute myocardial infarction

Early reperfusion for acute myocardial infarction (AMI) results in improved ventricular function and survival. There is a dearth of data on long-term survival (> 5 years) after percutaneous transluminal coronary angioplasty (PTCA) performed either as a primary procedure or in conjunction with thrombolytic therapy. We studied 160 patients who underwent PTCA during AMI between 1981 and 1987 either with (n = 101) or without (n = 59) streptokinase therapy. Mean time to reperfusion was 4.6 hours, and patency was achieved in 134 patients (84%). Mean discharge ejection fraction was 46 +/- 14%. Coronary artery bypass grafting was performed before dismissal in 34 patients (21%), including 21 of 130 patients (16%) with 1- or 2-vessel disease and 13 of 30 patients (43%) with 3-vessel disease (p < 0.05). Eleven patients (7%) died in the hospital. The 149 hospital survivors were followed for a mean of 69 +/- 21 months (median 72). During follow-up, 22 patients (15%) died, 21 (14%) had reinfarction, 23 (15%) underwent coronary artery bypass grafting, and 21 (14%) underwent repeat PTCA of the infarct-related artery. On univariate analysis, age > or = 62 years, multivessel disease, ejection fraction < or = 40%, previous AMI, and being a nonsmoker at the time of AMI were predictive of late mortality (p < 0.05 each variable). On multivariate analysis, only ejection fraction < or = 40% and prior AMI were predictive of late death. In patients treated with PTCA for AMI, late survival is excellent. Early surgical revascularization of high-risk patients may contribute to these encouraging results.

Failed direct coronary angioplasty for acute myocardial infarction: in-hospital outcome and predictors of death

OBJECTIVES

The purpose of this study was to compare the mechanisms, predictors and outcome of patients with failed direct coronary angioplasty of the infarct-related artery with those in patients with successful direct angioplasty.

BACKGROUND

Direct coronary angioplasty of the infarct-related artery, without antecedent thrombolytic therapy, is an effective treatment for patients with acute myocardial infarction. Concern has been expressed over high mortality rates in patients with failed direct infarct angioplasty.

METHODS

All patients treated by angioplasty were prospectively entered into a computer data base. The characteristics and outcome of all patients with failed direct angioplasty were reviewed and compared with those of patients with successful direct angioplasty.

RESULTS

Direct angioplasty was successful in 705 (94%) of 750 patients and unsuccessful in 45 (6%). Patients in the failure group were more likely to be in cardiogenic shock (22% vs. 7%, p < 0.003), to have had a previous myocardial infarction (44% vs. 28%, p < 0.03) and to have three-vessel coronary artery disease (44% vs. 23%, p < 0.003). Age, gender, ejection fraction, previous bypass surgery and diabetes mellitus were similar in both groups. Only the presence of multivessel coronary artery disease (p < 0.004) and cardiogenic shock (p < 0.025) were independent predictors of failed direct angioplasty. In-hospital death (31% vs. 4.8%, p < 0.001) and the need for emergency coronary artery bypass surgery (27% vs. 0.5%, p < 0.0001) were more frequent in patients with unsuccessful than in patients with successful direct angioplasty. Patients with failed direct angioplasty and in-hospital death usually had multiple high risk characteristics, including cardiogenic shock (50%), previous myocardial infarction (43%) and multivessel coronary artery disease (93%).

CONCLUSIONS

Direct coronary angioplasty is an effective method for establishing reperfusion in acute myocardial infarction. Procedural failure is infrequent, usually occurring in patients with high risk baseline characteristics.

Clinical applications of coronary sinus retroperfusion during high risk percutaneous transluminal coronary angioplasty

OBJECTIVES

This study was designed to determine the efficacy of synchronized coronary sinus retroperfusion of arterial blood in reducing myocardial ischemia associated with the performance of high risk coronary angioplasty.

BACKGROUND

Previous animal and clinical work has demonstrated the efficacy of this technique in supporting ischemic myocardium.

METHODS

Twenty-one patients were randomized to alternately receive coronary sinus retroperfusion support during either the second or the third coronary angioplasty balloon inflation, after an initial unsupported brief control inflation. Myocardial ischemia was assessed by the extent of echocardiographic left ventricular wall motion abnormality, quantified ST segment deviation and hemodynamic and anginal variables during balloon inflations performed with and without coronary sinus retroperfusion support. Regional wall motion score was defined as hyperkinesia (-1), normokinesia (0), hypokinesia (+1), akinesia (+2) and dyskinesia (+3).

RESULTS

A reduction in the echocardiographic left anterior descending regional wall motion score in retroperfusion-supported (1.7 +/- 2.1) versus unsupported (2.7 +/- 1.6) inflations (p < 0.05) was noted. Twelve-lead electrocardiographic monitoring revealed no additional ST segment deviation during supported (173 +/- 95 s) compared with unsupported (129 +/- 87 s) angioplasty inflations despite a significantly longer duration of supported inflations (p < 0.004). Mean and peak systolic coronary sinus pressures differed during supported inflations (21 +/- 6 and 44 +/- 13 mm Hg) versus unsupported inflations (10 +/- 4 and 16 +/- 5 mm Hg) (p < 0.001). There was no difference in hemodynamic or anginal variables.

CONCLUSIONS

A reduction in ischemia as defined by wall motion abnormality during retroperfusion-supported compared with unsupported angioplasty balloon inflations was documented. No additional ST segment deviation occurred during retroperfusion-supported compared with unsupported balloon inflations despite a significantly longer duration of supported inflations. No difference in hemodynamic or anginal variables was noted.

Impaired coronary flow reserve immediately after coronary angioplasty in patients with acute myocardial infarction

OBJECTIVE

To examine coronary flow reserve immediately after emergency coronary angioplasty in patients with acute myocardial infarction.

DESIGN

A 3 F coronary Doppler catheter was used to measure coronary blood flow velocity in the infarct artery and in the non-infarct artery. Maximal hyperaemia was produced by 10 mg of intracoronary papaverine and coronary flow reserve was calculated.

PATIENTS

11 patients with acute myocardial infarction undergoing both emergency coronary angioplasty (4.7 (3.6) h after the onset of chest pain (mean (SD))) and at follow up catheterisation 16 (4) days after angioplasty.

SETTING

Hiroshima City Hospital.

RESULTS

There was no stenosis of > or = 50% in the coronary artery of interest. Immediately after coronary angioplasty the mean (1 SD) coronary flow reserve of the infarct artery was significantly less than that of the non-infarct artery (1.4 (0.4) v 2.8 (0.8), p < 0.001). At follow up catheterisation the coronary flow reserve of the infarct artery increased almost to the value of the non-infarct artery (2.8 (1.2) v 3.1 (0.8) p = NS).

CONCLUSION

The coronary flow reserve in the infarct region was severely impaired immediately after reperfusion, even with a widely patent infarct artery. This could restrict the beneficial effects of reperfusion therapy, especially when there is a severe residual stenosis.

Cardiogenic shock complicating acute myocardial infarction in patients without heart failure on admission: incidence, risk factors, and outcome. SPRINT Study Group

PURPOSE

Patients with large myocardial infarction (MI) presenting with clinical signs of heart failure are at increased risk for subsequent development of cardiogenic shock and death. Little is known, however, about the development of cardiogenic shock among patients with acute MI presenting without clinical signs of heart failure. The aim of the present study was to examine the incidence, predictors for occurrence, and outcome of in-hospital development of cardiogenic shock among patients with acute MI without heart failure on admission.

PATIENTS AND METHODS

Clinical data of 5,839 consecutive patients hospitalized with acute MI were analyzed.

RESULTS

Of 3,465 (59%) patients without heart failure on admission (Killip class I), 89 (2.6%) developed cardiogenic shock during their hospital stay. This represented 24% of all cases of in-hospital cardiogenic shock in the entire group. Cardiogenic shock developed more than 24 hours after admission in 66% of cases. All but three patients with cardiogenic shock died whereas a 5% in-hospital mortality was found among patients without cardiogenic shock. Independent predictors for in-hospital shock were age (for a 10-year increment, adjusted relative odds [RO] = 2.45, 90% confidence interval [CI] = 1.50 to 4.02); female gender (RO = 1.51, 90% CI = 0.91 to 2.50); history of angina (RO = 2.64, 90% CI = 1.36 to 3.76); history of stroke (RO = 2.12, 90% CI = 1.26 to 6.35); peripheral vascular disease (RO = 1.99, 90% CI = 0.95 to 4.18); peak lactate dehydrogenase (LDH) greater than four times the normal (RO = 3.16, 90% CI = 1.79 to 5.57); and hyperglycemia on admission (RO = 3.52, 90% CI = 2.13 to 5.84). Patients with six risk factors (excluding LDH values) had an estimated probability of 35% for developing in-hospital cardiogenic shock.

CONCLUSIONS

(1) A significant proportion of MI patients who developed cardiogenic shock during hospitalization were free of heart failure on admission. (2) Our study identified several risk factors facilitating early identification of subgroups at risk for cardiogenic shock within otherwise low-risk patients.

Cardiogenic shock: elements of etiology, diagnosis, and therapy

Cardiogenic shock usually is the result of marked depression in myocardial function. Rapid recognition and stabilization are essential if the patient is to survive. A variety of cardiovascular conditions can lead to cardiogenic shock; the most common of these is acute myocardial infarction. Once stabilization of the cardiogenic shock patient has been effected, hemodynamic monitoring and definitive therapy should be attempted if appropriate. Intra-aortic balloon counterpulsation is effective in stabilizing these patients temporarily. Definitive therapy may include surgical or catheterization interventions. Mortality, even under the best of circumstances, remains high.

Circulatory support with shock due to acute myocardial infarction

Cardiogenic shock after acute myocardial infarction develops according to the amount of lost myocardium, function of remote myocardium, and the phenomenon of infarct expansion. Patients treated with mechanical support alone, without additional measures, have a mortality rate of 80%, the same as patients treated medically. Emergency angioplasty and emergency coronary artery bypass grafting can reduce mortality in certain subsets of patients to 40%. Patients with more severe shock and secondary organ dysfunction may be treated with mechanical bridging to transplantation with survival rates varying between 45% and 76%. Percutaneous support systems may be used to resuscitate a patient or to temporize, allowing time to perform diagnostic studies to determine if the patient is suitable for revascularization or heart transplantation. Intravenous enoximone may improve cardiac function as well and thus allow better decision making for further therapy.

Prognosis in cardiogenic shock after acute myocardial infarction in the interventional era

OBJECTIVES

The purpose of this study is to describe the outcome in cardiogenic shock treated with aggressive reperfusion therapy and to identify factors predictive of in-hospital and long-term mortality.

BACKGROUND

Cardiogenic shock is the most common cause of death in patients admitted to the coronary care unit. Although studies have reported lower mortality rates in shock treated with angioplasty, few studies have described a cohort of patients with shock who were not selected because they were most likely to benefit from reperfusion therapy.

METHODS

A consecutive series of 200 patients admitted with acute myocardial infarction complicated by cardiogenic shock were studied.

RESULTS

The in-hospital mortality rate was 53%. Variables with significant univariable association with in-hospital death included patency of the infarct-related artery, patient age, lowest cardiac index, highest arteriovenous oxygen difference and left main coronary artery disease. The most important independent predictors of in-hospital death were patency of the infarct-related artery, cardiac index and peak creatine kinase, MB fraction. The mortality rate in patients with patent infarct-related arteries was 33% versus 75% in those with closed arteries and 84% in those in whom arterial patency was unknown. Patients who survived to hospital discharge were followed up for a median of 2 years, with a mortality rate of 18% after 1 year. The best descriptors of the relation between these variables and postdischarge mortality included age, peak creatine kinase, ejection fraction and patency of the infarct-related artery.

CONCLUSIONS

In a large consecutive series of patients with cardiogenic shock with complete follow-up, patency of the infarct-related artery was most strongly associated with in-hospital and long-term mortality. This finding supports an aggressive interventional strategy in patients with cardiogenic shock.

Pathogenesis and management of acute heart failure and cardiogenic shock: role of inotropic therapy

Patients with acute heart failure or cardiogenic shock following myocardial infarction have a high mortality. The first priority is to salvage any remaining viable myocardium, either by thrombolytic agents or, if necessary, by coronary angioplasty. A mechanical cause for the heart failure or shock needs to be excluded. Thereafter, the optimal therapeutic regimen needs to be chosen on the basis of each patient's hemodynamic profile. Patients can be broadly classified into three groups: (1) patients with a high left ventricular filling pressure (> 18 mm Hg) and a cardiac index < 2.2 L/min/m2 but systolic arterial pressure > 100 mm Hg; (2) patients with a systolic arterial pressure < 90 mm Hg, left ventricular filling pressure > 18 mm Hg, and cardiac index < 2.2 L/min/m2; and (3) patients with an elevated right ventricular filling pressure (> 10 mm Hg) and cardiac index < 2.2 L/min/m2 and a systolic arterial pressure < 100 mm Hg. Patients in the first subset usually require the use of vasodilator therapy and/or dobutamine. The choice of inotropic agent in patients in the second hemodynamic subset depends on the degree of systemic hypotension; dopamine is usually preferred initially because it increases arterial pressure in addition to improving cardiac output. Once the systemic blood pressure has been stabilized, dobutamine can be substituted for superior augmentation of cardiac output and its additional beneficial effects on the left ventricular filling pressure. Norepinephrine may be indicated in cases of severe systemic hypotension. Patients in hemodynamic subset 3, ie, right ventricular infarction, are treated with volume expansion and dobutamine. Use of nonpharmacologic means of circulatory support, eg, intra-aortic balloon pump or left ventricular assist device may also be required in any of these subsets.

Myocardial revascularization. Coronary angioplasty and bypass surgery indications

Coronary artery bypass grafting (CABG) and percutaneous transluminal coronary angioplasty (PTCA) have been performed increasingly over the last 20 and 10 years, respectively. The growth in PTCA is both complementary and threatening to CABG. The controversy between cardiologists and cardiac surgeons over the role of each procedure will no doubt continue as new devices are developed for coronary interventions. This article reviews the controversy and provides information to internists so that they will be fully prepared to advise patients about their treatment options.

Acute myocardial infarction. An updated protocol for thrombolytic therapy

Only a small percentage of patients who have acute myocardial infarction receive the benefit of intravenous thrombolytic therapy, often because logistics result in unnecessary pre-hospital and in-hospital delays. Dr Selig therefore recommends that a streamlined protocol be available and that it be updated at regular intervals to ensure that this time-dependent therapy is more routinely utilized.

A patency-oriented strategy for early management of acute myocardial infarction using emergency coronary angiography and selective coronary angioplasty

From June 1988 to March 1991, an unselected cohort of 150 consecutive patients with acute myocardial infarction (AMI) (less than 6 hours) was managed according to a strategy designed to ensure early patency of the infarct-related artery in the maximum number of patients. The following procedures were used: (1) intravenous thrombolysis, which was the usual treatment (n = 103), followed in 98 cases by emergency coronary angiography 90 minutes after the beginning of thrombolysis. This identified 31 thrombolysis failures (32%) and led to 19 rescue angioplasties (18 successes). All patients were then scheduled for predischarge angiography. (2) Direct angioplasty, which was performed in 40 patients because of contraindications to thrombolysis (n = 23), cardiogenic shock (n = 3), diagnostic doubt (n = 7) or "ideal" conditions for direct angioplasty (n = 7). Success (defined as Thrombolysis in Myocardial Infarction [TIMI] flow greater than 1, with a residual stenosis less than 50% in the infarct-related artery) was achieved in 36 of 40 patients (90%). (3) The 7 remaining patients were given conventional medical treatment because of advanced age, contraindications to thrombolysis and angioplasty, or spontaneous reperfusion (confirmed by emergency angiography). In all, emergency angioplasty was performed in the acute phase in 39% of the 150 patients in this nonselected cohort.(ABSTRACT TRUNCATED AT 250 WORDS)

Mechanisms of early death despite thrombolytic therapy: Experience from the Thrombolysis in Myocardial Infarction Phase II (TIMI II) study

Mechanisms of death among patients who died within 18 h of enrollment in the Thrombolysis in Myocardial Infarction Phase II (TIMI II) study were analyzed. Of 3,339 patients enrolled, 32 died within the 1st 4 h and 31 died within the subsequent 14 h. Thirteen of the 63 patients had shock at enrollment; 22 had advanced hemodynamic compromise without shock and 28 initially had minimal to no compromise. Prior infarction was present in 16 patients (25%). Pump failure was responsible for 39 early deaths (62%), ventricular rupture for 10 (16%), arrhythmia for 8 (13%) and complications of therapy for 6 (10%). Nine of 720 patients randomized to immediate intravenous beta-adrenergic blocking agent therapy had an early death compared with 6 of 714 assigned to deferred beta-blocker therapy. Thus, mortality is highest in the early hours after myocardial infarction, even in patients treated with thrombolytic therapy and is most frequently due to pump failure. These results imply that efforts to reduce mortality during this critical time period should be directed at prevention, limitation or palliation of early pump failure.

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)

Cardiogenic shock complicating acute myocardial infarction: the use of coronary angioplasty and the integration of the new support devices into patient management

Conventional therapy for cardiogenic shock complicating acute myocardial infarction continues to be associated with a high in-hospital mortality rate. Hemodynamic support with new mechanical devices and emergency coronary revascularization may alter the long-term prognosis for patients with this complication. Between July 1985 and March 1990, 68 patients presented to the University of Michigan with acute myocardial infarction and cardiogenic shock. Interventions performed included thrombolytic therapy (46%), intraaortic balloon pump counterpulsation (70%), cardiac catheterization (86%), coronary angioplasty (73%), emergency coronary artery bypass grafting/ventricular septal defect repair (15%), Hemopump insertion (11%), percutaneous cardiopulmonary support (4%) and ventricular assist device (3%). The 30-day survival rate was significantly better in patients who had successful angioplasty of the infarct-related artery than in patients with failed angioplasty (61% vs. 7%, p = 0.002) or no attempt at angioplasty (61% vs. 14%, p = 0.003). This difference was maintained over the 1-year follow-up period. The only clinical variable that predicted survival was age less than 65 years. The early use of the new support devices in 10 patients was associated with death in 8 (80%), but this poor outcome may reflect a selection bias for an especially high risk population. Collectively, these recent data continue to suggest that emergency revascularization with angioplasty may reduce the mortality rate, but further study is required to define optimal utilization and integration of new support devices.

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.

Thrombolytic therapy: adjuvant mechanical intervention for acute myocardial infarction

Following successful pharmacologic thrombolysis, early coronary angiography frequently shows a tight residual stenosis in the infarct-related artery at the site of recent occlusion. Approaches to the management of the residual stenosis have undergone a gradual evolution from an aggressive strategy of immediate balloon dilation to a more conservative approach. Randomized, controlled trials have indicated that immediate percutaneous transluminal coronary angioplasty (PTCA) is associated with no greater recovery in regional or global left ventricular function, and a tendency toward an increased incidence of complications, including the need for emergency coronary artery surgery and blood transfusion. The role of immediate rescue PTCA for failed thrombolysis has not been as rigorously investigated, but selected patients, including those with evidence of ongoing myocardial ischemia or hemodynamic instability, may benefit from this approach. A major source of current controversy is the value of routine coronary angiography after uncomplicated myocardial infarction. Two carefully conducted trials have indicated that a conservative strategy of clinically indicated, predischarge cardiac catheterization may be associated with an increased need for readmission and late, elective cardiac catheterization when compared with a more invasive strategy of routine coronary angiography, but that the conservative approach is not associated with an increased incidence of death or reinfarction. Provision was not made in these studies, however, for evaluating the positive economic and psychologic impact of early coronary angiography, early hospital discharge, and early return to work of patients with a favorable postinfarction prognosis. It is concluded that early mechanical revascularization following thrombolysis should be considered for ongoing myocardial ischemia, but should otherwise be deferred pending the results of predischarge functional studies. For most patients, routine coronary angiography is likely to remain an important diagnostic tool and an integral component of the management of the convalescent phase of acute myocardial infarction.

Congestive heart failure in acute myocardial infarction. Treating the spectrum from mild failure to cardiogenic shock

Congestive heart failure (CHF) accompanying acute myocardial infarction (MI) may have various manifestations, ranging from mild failure to cardiogenic shock. Initial treatment depends on the cause, which is usually determined through careful physical examination. The Forrester hemodynamic classification is useful in this determination. A practical working knowledge of the clinical correlates of left ventricular dysfunction in acute MI allows rational use of the several classes of drugs available to treat CHF. With severe CHF, invasive monitoring is usually required, and mechanical complications of MI need to be identified and managed appropriately.

Cardiogenic shock after acute myocardial infarction. Incidence and mortality from a community-wide perspective, 1975 to 1988

BACKGROUND

Cardiogenic shock resulting from acute myocardial infarction is a serious complication with a high mortality rate, but little is known about whether its incidence or outcome has changed over time. As part of an ongoing population-based study of acute myocardial infarction, we examined trends over time in the incidence and mortality rate of cardiogenic shock after acute myocardial infarction.

METHODS

We studied 4762 patients with acute myocardial infarction who were admitted to 16 hospitals in the Worcester, Massachusetts, metropolitan area between 1975 and 1988. We determined the incidence of and short-term and long-term mortality due to cardiogenic shock in each of six years during this study period.

RESULTS

The incidence of cardiogenic shock complicating acute myocardial infarction remained relatively constant, averaging 7.5 percent. Multivariate regression analysis that controlled for variables affecting incidence revealed significant though inconsistent temporal trends in the incidence of cardiogenic shock. As compared with the risk in 1975, the adjusted relative risk (with 95 percent confidence interval) was 0.83 (0.54 to 1.28) in 1978, 0.96 (0.63 to 1.48) in 1981, 0.68 (0.42 to 1.12) in 1984, 1.16 (0.70 to 1.92) in 1986, and 1.65 (0.99 to 2.77) in 1988. The overall in-hospital mortality rate among patients with cardiogenic shock was significantly higher than that among patients without this complication (77.7 percent vs. 13.5 percent, P less than 0.001). The in-hospital mortality among the patients with shock did not improve between 1975 (73.7 percent) and 1988 (81.7 percent). Long-term survival during the 14-year follow-up period was significantly worse among patients who survived cardiogenic shock during hospitalization than among patients who did not have shock (P less than 0.001).

CONCLUSIONS

The results of this observational, community-wide study suggest that neither the incidence nor the prognosis of cardiogenic shock resulting from acute myocardial infarction has improved over time. Both in-hospital and long-term survival remain poor for patients with this complication.

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.