Status of the myocardium and infarct-related coronary artery in 19 necropsy patients with acute recanalization using pharmacologic (streptokinase, r-tissue plasminogen activator), mechanical (percutaneous transluminal coronary angioplasty) or combined types of reperfusion therapy

Coronary No-Reflow after Primary Percutaneous Coronary Intervention-Current Knowledge on Pathophysiology, Diagnosis, Clinical Impact and Therapy

Coronary no-reflow (CNR) is a frequent phenomenon that develops in patients with ST-segment elevation myocardial infarction (STEMI) following reperfusion therapy. CNR is highly dynamic, develops gradually (over hours) and persists for days to weeks after reperfusion. Microvascular obstruction (MVO) developing as a consequence of myocardial ischemia, distal embolization and reperfusion-related injury is the main pathophysiological mechanism of CNR. The frequency of CNR or MVO after primary PCI differs widely depending on the sensitivity of the tools used for diagnosis and timing of examination. Coronary angiography is readily available and most convenient to diagnose CNR but it is highly conservative and underestimates the true frequency of CNR. Cardiac magnetic resonance (CMR) imaging is the most sensitive method to diagnose MVO and CNR that provides information on the presence, localization and extent of MVO. CMR imaging detects intramyocardial hemorrhage and accurately estimates the infarct size. MVO and CNR markedly negate the benefits of reperfusion therapy and contribute to poor clinical outcomes including adverse remodeling of left ventricle, worsening or new congestive heart failure and reduced survival. Despite extensive research and the use of therapies that target almost all known pathophysiological mechanisms of CNR, no therapy has been found that prevents or reverses CNR and provides consistent clinical benefit in patients with STEMI undergoing reperfusion. Currently, the prevention or alleviation of MVO and CNR remain unmet goals in the therapy of STEMI that continue to be under intense research.

Reperfusion therapy-What's with the obstructed, leaky and broken capillaries?

Microvascular dysfunction is well established as an early and rate-determining factor in the injury response of tissues to ischemia and reperfusion (I/R). Severe endothelial cell dysfunction, which can develop without obvious morphological cell injury, is a major underlying cause of the microvascular abnormalities that accompany I/R. While I/R-induced microvascular dysfunction is manifested in different ways, two responses that have received much attention in both the experimental and clinical setting are impaired capillary perfusion (no-reflow) and endothelial barrier failure with a transition to hemorrhage. These responses are emerging as potentially important determinants of the severity of the tissue injury response, and there is growing clinical evidence that they are predictive of clinical outcome following reperfusion therapy. This review provides a summary of animal studies that have focused on the mechanisms that may underlie the genesis of no-reflow and hemorrhage following reperfusion of ischemic tissues, and addresses the clinical evidence that implicates these vascular events in the responses of the ischemic brain (stroke) and heart (myocardial infarction) to reperfusion therapy. Inasmuch as reactive oxygen species (ROS) and matrix metalloproteinases (MMP) are frequently invoked as triggers of the microvascular dysfunction elicited by I/R, the potential roles and sources of these mediators are also discussed. The available evidence in the literature justifies the increased interest in the development of no-reflow and hemorrhage in heart and brain following reperfusion therapy, and suggests that these vascular events may be predictive of poor clinical outcome and warrant the development of targeted treatment strategies.

Simplifying electrocardiographic assessment in STEMI reperfusion management: Pros and cons

Current guidelines on STEMI reperfusion management do not incorporate further electrocardiographic details over the presence of significant ST elevation. Fibrinolysis is considered an alternative therapy to primary PCI if there is a long PCI-related delay, but the 2 therapies should not be combined. Meanwhile, reperfusion for ischemic stroke has evolved on mechanistic understanding - reperfusion benefit being greatest in the patient with small "core" infarct and large ischemic "penumbra". Fibrinolysis is not regarded as an alternative to mechanical thrombectomy, and the 2 therapies can be combined. In this article describing how reperfusion regimes have evolved along different paths for STEMI and for ischemic stroke, a new concept is made that in STEMI infarct lead Q waves can be the counterpart of the "core" and ST elevation the "penumbra". Suggestions to modify STEMI treatment algorithms are made, exploring further the relative role of (pre-hospital) fibrinolysis versus PCI particularly in younger patients presenting at the onset of their STEMI (no Q waves). In contrast, some patients particularly the older ones with more evolved STEMI (large Q waves present) may be much more suited for PCI despite expecting a long delay. The article finishes by describing potential future alterations in the method of reperfusion. Despite primary PCI being the well-established therapy, there are rooms for further research to optimize STEMI outcomes.

Trends in the clinical and pathological characteristics of cardiac rupture in patients with acute myocardial infarction over 35 years

Background

There is little known about whether the clinical and pathological characteristics and incidence of cardiac rupture (CR) in patients with acute myocardial infarction (AMI) have changed over the years.

Methods and Results

The incidence and clinical characteristics of CR were investigated in patients with AMI, who were divided into 3 cohorts: 1977–1989, 1990–2000, and 2001–2011. Of a total of 5699 patients, 144 were diagnosed with CR and 45 survived. Over the years, the incidence of CR decreased (1977–1989, 3.3%; 1990–2000, 2.8%; 2001–2011, 1.7%; P=0.002) in association with the widespread adoption of reperfusion therapy. The mortality rate of CR decreased (1977–1989, 90%; 1990–2000, 56%; 2001–2011, 50%; P=0.002) in association with an increase in the rate of emergent surgery. In multivariable analysis, first myocardial infarction, anterior infarct, female sex, hypertension, and age >70 years were significant risk factors for CR, whereas impact of hypertension on CR was weaker from 2001 to 2011. Primary percutaneous coronary intervention (PPCI) was a significant protective factor against CR. In 64 autopsy cases with CR, myocardial hemorrhage occurred more frequently in those who underwent PPCI or fibrinolysis than those who did not receive reperfusion therapy (no reperfusion therapy, 18.0%; fibrinolysis, 71.4%; PPCI, 83.3%; P=0.001).

Conclusions

With the development of medical treatment, the incidence and mortality rate of CR have decreased. However, first myocardial infarction, anterior infarct, female sex, and old age remain important risk factors for CR. Adjunctive cardioprotection against reperfusion‐induced myocardial hemorrhage is emerging in the current PPCI era.

Effectiveness and safety of percutaneous coronary intervention after fibrinolytic therapy for ST-segment elevation acute myocardial infarction

The goal of treatment of an acute ST-segment elevation myocardial infarction is the timely restoration of myocardial blood flow to decrease myocardial necrosis and thereby preserve cardiac tissue and overall function. Mainstays of reperfusion treatment include fibrinolytic therapy and/or primary percutaneous coronary intervention. In those patients who are treated with fibrinolysis, there is debate as to whether and when they should also undergo subsequent percutaneous coronary intervention. In conclusion, the investigators review the published reports on systematic percutaneous coronary intervention after fibrinolytic therapy in the treatment of ST-segment elevation myocardial infarction and discuss the rationale behind this treatment strategy.

Early percutaneous coronary intervention after fibrinolysis for acute ST elevation myocardial infarction: results of two German multi‐centre registries (ACOS and GOAL)

OBJECTIVES

We evaluated the outcome of early percutaneous coronary intervention (PCI) after fibrinolysis in patients presenting with ST elevation myocardial infarction (STEMI) in clinical practice.

RESULTS

2230 consecutive patients with STEMI treated with fibrinolysis were divided into two groups: patients treated with fibrinolysis only (n = 1540) or with additional PCI (n = 690) within a median of 150 min. In-hospital mortality (9.3% versus 5.9%) and death/myocardial re-infarction (13.9% versus 9.7%) occurred significantly less often in the PCI group. After adjustment for the confounding factors in the propensity score analysis PCI did not significantly affect hospital mortality (OR 0.88, 95% CI 0.57-1.36) and death/myocardial re-infarction (OR 0.86, 95% CI 0.61-1.20) in the overall patients collective. Major bleeding complications were observed more often in the PCI group (7.3% versus 4.2%). In patients with a higher risk profile (TIMI risk score > or = 5) (n = 494) PCI was associated with a significant reduction of hospital mortality (OR 0.40, 95% CI 0.20-0.78) and death/myocardial re-infarction (OR 0.36, 95 % CI 0.19-0.67).

CONCLUSIONS

In the overall patients' collective early PCI after fibrinolysis is not associated with an improved clinical outcome. However, in patients with a higher risk profile an early invasive strategy is associated with a risk reduction for mortality and the combined endpoint of death/myocardial re-infarction.

Systematic review of fibrinolytic-facilitated percutaneous coronary intervention: potential benefits and future challenges

BACKGROUND

Facilitated percutaneous coronary intervention (PCI) is defined as the administration of fibrinolytic therapy and/or glycoprotein (GP) IIb/IIIa inhibitors to minimize myocardial ischemia time while waiting for PCI. A pooled meta-analysis suggested that facilitated PCI was associated with higher rates of mortality and morbidity compared with nonfacilitated PCI.

OBJECTIVE

The heterogeneous and complex trials of facilitated PCI were systematically reviewed to identify where this strategy may be beneficial and deserving of further research.

METHODS

MEDLINE, EMBASE, the Cochrane database, the Internet and conference proceedings were searched to obtain relevant trials. Human studies that randomly assigned patients to fibrinolytic-facilitated PCI (administration of fibrinolytic therapy alone or in combination with GP IIb/IIIa inhibitors before angiography) versus nonfacilitated PCI were included.

RESULTS

Nine trials encompassing 3836 patients were reviewed. The facilitated PCI strategy was fibrinolytic therapy alone in seven trials and half-dose fibrinolytic therapy plus GP IIb/IIIa inhibitors in two trials. In patients who had fibrinolysis less than 2 h after symptom onset (mainly in the prehospital setting) and/or slightly delayed PCI 3 h to 24 h after fibrinolysis, facilitated PCI was associated with the greatest Thrombolysis In Myocardial Infarction (TIMI) grade 3 flow and a trend toward reduced mortality. Overall, facilitated PCI was associated with increased intracranial hemorrhage and reinfarction. Combining half-dose fibrinolytic therapy and GP IIb/IIIa inhibitors reduced reinfarction but increased major bleeding.

CONCLUSIONS

Facilitated PCI cannot be recommended outside of experimental protocols at this time. Further research should focus on selecting patients with higher benefit-to-risk ratios and performing prehospital fibrinolysis with optimal antiplatelet or antithrombin therapy, as well as slightly delayed PCI in patients who are stable or geographically removed from PCI facilities.

Oxidative stress parameters in erythrocytes of post-reperfused patients with myocardial infarction

The effect of reperfusion of patients with myocardial infarction on the levels of some anti-oxidant enzymes, total thiols, malondialdehyde formation in erythrocytes and plasma ascorbate levels have been investigated. Significantly decreased activities of catalase and superoxide dismutase and decreased levels of total thiols in RBC's and ascorbic acid in plasma suggest that reperfusion of the infarcted myocardium leads to oxidative stress conditions wherein anti-oxidant mechanisms become less effective in coping with the oxidative insult. This view is further supported by the observation that in the post reperfused patients there is a highly significant enhancement in the levels of malondialdehyde.

Acute Coronary Care in the Elderly, Part II

Background— Age is an important determinant of outcomes for patients with acute coronary syndromes. However, community practice reveals a disproportionately lower use of cardiovascular medications and invasive treatment even among elderly patients who would stand to benefit. Limited trial data are available to guide care of older adults, which results in uncertainty about benefits and risks, particularly with newer medications or invasive treatments and in the setting of advanced age and complex health status.

Methods and Results— Part II of this American Heart Association scientific statement summarizes evidence on presentation and treatment of ST-segment–elevation myocardial infarction in relation to age (<65, 65 to 74, 75 to 84, and ≥85 years). The purpose of this statement is to identify areas in which the evidence is sufficient to guide practice in the elderly and to highlight areas that warrant further study. Treatment-related benefits should rise in an elderly population, yet data to confirm these benefits are limited, and the heterogeneity of older populations increases treatment-associated risks. Elderly patients with ST-segment–elevation myocardial infarction more often have relative and absolute contraindications to reperfusion, so eligibility for reperfusion declines with age, and yet elderly patients are less likely to receive reperfusion even if eligible. Data support a benefit from reperfusion in elderly subgroups up to age 85 years. The selection of reperfusion strategy is determined more by availability, time from presentation, shock, and comorbidity than by age. Additional data are needed on selection and dosing of adjunctive therapies and on complications in the elderly. A “one-size-fits-all” approach to care in the oldest old is not feasible, and ethical issues will remain even in the presence of adequate evidence. Nevertheless, if the contributors to treatment benefits and risks are understood, guideline-recommended care may be applied in a patient-centered manner in the oldest subset of patients.

Conclusions— Few trials have adequately described treatment effects in older patients with ST-segment–elevation myocardial infarction. In the future, absolute and relative risks for efficacy and safety in age subgroups should be reported, and trials should make efforts to enroll the elderly in proportion to their prevalence among the treated population. Outcomes of particular relevance to the older adult, such as quality of life, physical function, and independence, should also be evaluated, and geriatric conditions unique to this age group, such as frailty and cognitive impairment, should be considered for their influence on care and outcomes. With these efforts, treatment risks can be minimized, and benefits can be placed within the health context of the elderly patient.

Thrombolysis Increases the Risk of Free Wall Rupture in Patients with Acute Myocardial Infarction Undergoing Percutaneous Coronary Intervention

In spite of the progress made in acute angiographic evaluation and obtaining durable reperfusion of acute myocardial infarction (AMI) in the past two decades, cardiac free wall rupture (FWR) is still one of the causes of mortality following AMI. In this study, we evaluated the role of thrombolysis in the risk of FWR in AMI patients treated with acute percutaneous coronary intervention (PCI). Among 3,786 consecutive AMI patients seen between 1985 and 2003, 3,066 patients were treated by primary PCI or rescue PCI, with or without additional thrombolysis. FWR occurred in 24 of 3,066 patients (0.8%) treated by PCI; female gender (1.4% vs 0.6%, P=0.001), age >75 years, (1.4% vs 0.6%, P=0.001) left main coronary artery (LMCA)-related infarction, (4.5% vs all other arteries, P=0.015), and thrombolytic use (3.1% vs 0.4%, P<0.001) were all associated with higher rates of FWR by univariate analysis. In patients treated with PCI and thrombolysis, FWR occurred in 2.7% with optimal PCI results but in only 4.9% if PCI was unsuccessful (P=NS). The incidence of FWR in patients with optimal PCI without thrombolysis was 0.4% (P<0.001). Multivariable analysis identified thrombolytic use (odds ratio [OR]: 8.49, 95% confidence interval [CI]: 3.66-19.7, P<0.001), LMCA-related infarction (OR: 7.06, 95% CI: 1.89-26.4, P=0.004), and female gender (OR: 3.02, 95% CI: 1.27-7.21, P=0.013) as independent predictors of FWR. Thrombolysis is one of the contributing causes of FWR in AMI patients undergoing PCI, even when PCI is successful.

Ventricular septal rupture masquerading as coronary perforation during intervention for acute myocardial infarction

Ventricular septal rupture is a serious complication of acute myocardial infarction. We experienced a case of septal rupture immediately after primary angioplasty with thrombolysis, whose angiographic findings were similar to those of coronary perforation. The progression of septal rupture was delineated by the serial angiograms.

Moderate Systemic Hypotension During Reperfusion Reduces the Coronary Blood Flow and Increases the Size of Myocardial Infarction in Pigs

STUDY OBJECTIVE

s: To examine the effects of low arterial BP (ABP) during reperfusion on the extent of myocardial infarction and on coronary blood flow (CBF) in an occlusion/reperfusion experimental model.

DESIGN

Prospective, randomized animal study.

SETTING

University hospital.

PARTICIPANTS

Normal pigs that were anesthetized, intubated, and mechanically ventilated.

INTERVENTIONS

Twenty-seven open-chest pigs underwent occlusion of the mid left anterior descending (LAD) coronary artery for 1 h followed by reperfusion for 2 h. During reperfusion, the animals were randomly assigned to either continuous infusion of nitroglycerin in therapeutic doses and fluid infusion at rates to maintain a mean ABP >or= 80 mm Hg (group 1, n = 13), or continuous nitroglycerin infusion at rates to maintain a mean ABP between 60 mm Hg and 75 mm Hg (group 2, n = 14).

MEASUREMENTS AND RESULTS

The hemodynamics and the coronary ABP distal to the occlusion were recorded throughout the experiment. In addition, the LAD CBF and peak hyperemia CBF before occlusion and during reperfusion periods were measured by transit-time flowmetry. At the end of the experiment, the infarcted left ventricular myocardial size was measured. There were no significant hemodynamic differences, including the distal coronary arterial pressure, between the two groups before or during the LAD artery occlusion period. During reperfusion, mean ABP was 90 +/- 3 mm Hg in group 1 vs 69 +/- 3 mm Hg in group 2 (p < 0.001). In group 1, the infarcted myocardium represented 50.3 +/- 4.3% of the myocardium at risk, vs 69.4 +/- 7.2% in group 2 (p < 0.001). During reperfusion, CBF and peak hyperemia CBF were significantly higher in group 1 than in group 2.

CONCLUSIONS

Low ABP during reperfusion increases the size of myocardial infarction and decreases CBF.

Usefulness of frequent arrhythmias after epicardial recanalization in anterior wall acute myocardial infarction as a marker of cellular injury leading to poor recovery of left ventricular function

Ventricular arrhythmias are associated with epicardial reperfusion but may also be a sign of cellular injury, which affects recovery of left ventricular (LV) function. To assess the correlation between reperfusion arrhythmias and the change in LV function after the acute phase in reperfused acute myocardial infarction (AMI), 62 patients with reperfused anterior wall AMI were studied. All patients underwent 24-hour Holter recording, echocardiography, and coronary angiography during the acute phase of AMI. Echocardiography was repeated at 1 to 2 months after AMI. Correlations between ventricular arrhythmias in the reperfusion phase and the change in LV wall motion score (WMS) during follow-up were studied. The number of reperfusion arrhythmias was significantly higher in patients with further deterioration of LV function; there were 5-, 14-, 131-, and 11-fold increases in isolated premature ventricular complexes (PVCs), PVCs in couplets, PVCs in bigeminy, and total PVCs, respectively, in patients with further increases in WMS after the acute phase. The incidence of repetitive, frequent, and early accelerated idioventricular rhythms (AIVRs) was correlated significantly with the change in LV function, with 129- and 105-fold increases in numbers of early AIVRs and total AIVRs, respectively, in patients with further worsening of LV function during follow-up. The incidence and the number of long-lasting nonsustained ventricular tachycardias as well as the number of rapid ventricular tachycardias and total ventricular tachycardia episodes were also correlated significantly with further deterioration. Thus, frequent arrhythmias associated with epicardial reperfusion strongly correlate with further worsening of LV function after the acute phase of AMI. This supports the hypothesis that these reperfusion arrhythmias are probably a noninvasive marker of cellular injury.

Beneficial effects of immediate stenting after thrombolysis in acute myocardial infarction

OBJECTIVES

The Southwest German Interventional Study in Acute Myocardial Infarction (SIAM III) investigated potentially beneficial effects of immediate stenting after thrombolysis as opposed to a more conservative treatment regimen.

BACKGROUND

Treatment of acute myocardial infarction (AMI) by thrombolysis is compromised by Thrombolysis In Myocardial Infarction (TIMI) 3 flow rates of only 60% and high re-occlusion rates of the infarct-related artery (IRA). Older studies showed no benefit of coronary angioplasty after thrombolysis compared with thrombolytic therapy alone. This observation has been challenged by the superiority of primary stenting over balloon angioplasty in AMI.

METHODS

The SIAM III study was a multicenter, randomized, prospective, controlled trial in patients receiving thrombolysis in AMI (<12 h). Patients of group I were transferred within 6 h after thrombolysis for coronary angiography, including stenting of the IRA. Group II received elective coronary angiography two weeks after thrombolysis with stenting of the IRA.

RESULTS

A total of 197 patients were randomized, 163 patients fulfilled the secondary (angiographic) inclusion criteria (82 in group I, 81 in group II). Immediate stenting was associated with a significant reduction of the combined end point after six months (ischemic events, death, reinfarction, target lesion revascularization 25.6% vs. 50.6%, p = 0.001).

CONCLUSIONS

Immediate stenting after thrombolysis leads to a significant reduction of cardiac events compared with a more conservative approach including delayed stenting after two weeks.

Outcomes of primary coronary angioplasty and angioplasty after initial thrombolysis in the treatment of 374 consecutive patients with acute myocardial infarction

BACKGROUND

In patients with acute myocardial infarction (MI), the efficacy of thrombolysis is low. Angioplasty after failed thrombolysis (rescue percutaneous coronary angioplasty [PTCA]) has been associated with an increase in the incidence of inhospital complications. It has been proposed that these complications result from the procedure itself. Thus, the aim of this study was to compare the efficacy, inhospital complications, and mortality rate of patients with MI who are treated with primary PTCA and PTCA after initial thrombolysis (rescue or immediate rescue) in an experienced clinical center specializing in percutaneous coronary interventions.

METHODS AND RESULTS

The study group consisted of consecutive patients with MI treated with primary PTCA (n = 195) or PTCA after initial thrombolysis (n = 179). The study was performed in a referral center with a 24-hour catheter-laboratory service. The success rate of the procedure was 90.5% and 88.2% in the PTCA after initial thrombolysis group and primary PTCA group, respectively. The groups did not differ in the frequency of reocclusion, emergency surgical revascularization (coronary artery bypass grafting), or stroke. In patients without cardiogenic shock, the inhospital mortality rates were 3.2% and 0.6% in the rescue and immediate rescue group and primary PTCA group, respectively (not significant). In a subgroup of patients with cardiogenic shock, the mortality rate was 36.0% in the initial thrombolysis PTCA group and 30.8% in the primary PTCA group. However, after successful PTCA in this subgroup, the mortality rate dropped to 18% and 10%, respectively.

CONCLUSIONS

After initial thrombolysis, PTCA is safe, effective, and likely to restore grade 3 Thrombolysis In Myocardial Infarction flow in about 90% of patients. When available, immediate rescue PTCA should be performed in all patients, including patients with cardiogenic shock.

Safety of coronary stenting early after thrombolysis in patients with acute myocardial infarction: one- and six-month clinical and angiographic evolution

To determine the feasibility and safety of early posthrombolysis coronary stenting and the incidence of further reocclusion, we followed 99 consecutive patients with acute myocardial infarction thrombolyzed with rt-PA 2.0 +/- 0.8 hr after onset. Culprit artery was stented 14.0 +/- 7.0 hr after thrombolysis. All patients underwent clinical and angiographic follow-up at 1 and 6 months. Angiographic success was achieved in 99% of cases. Neither major cardiac events nor bleeding or vascular complications occurred during hospital stay. At 30 days, no events occurred and normal flow persisted in all stented arteries. At 6 months, only one artery reoccluded (1%), resulting in a nonfatal reinfarction. Restenosis rate was 21%. Contribution of the infarcted area to left ventricular function significantly increased from baseline to 30-day and to 6-month evaluations. Thus, early posthrombolysis stenting is a safe strategy with a low reocclusion rate, which seems to allow functional recovery of the infarcted area. Further studies are necessary to define its impact on survival and cost-effectiveness.

Long-term follow-up of a randomized study of primary stenting versus angioplasty in acute myocardial infarction

PURPOSE

Primary stenting leads to better short-term outcomes than does balloon angioplasty among patients with acute myocardial infarction, but there are no data available on long-term follow-up.

SUBJECTS AND METHODS

We designed a randomized study with long-term follow-up to compare primary angioplasty with angioplasty accompanied by implantation of a silicon carbide-coated stent in patients within 24 hours after the onset of acute myocardial infarction. All 88 patients had lesions that were suitable for coronary stenting.

RESULTS

There were 44 patients in each of the randomization groups. During long-term follow-up (mean +/- SD: 710+/-282 days), primary stenting was associated with a reduction in the combined endpoint of death, reinfarction, or target vessel revascularization (10 [23%] versus 19 [43%], P = 0.03); death (4 [9%] versus 8 [18%], P = 0.18); reinfarction (1 [2%] versus 4 [9%], P = 0.18); and target lesion revascularization (7 [16%] versus 15 [34%], P = 0.04). Rehospitalization due to ischemic events (unstable angina or reinfarction) was also less frequent in the stent group (6 [14%] versus 10 [23%], P = 0.20).

CONCLUSION

Primary stenting in acute myocardial infarction is significantly superior to angioplasty alone in both short-term and long-term follow-up.

Primary angioplasty for acute myocardial infarction in the elderly

Elderly patients with acute myocardial infarction present a formidable therapeutic challenge. Although there appears to be a survival benefit from thrombolytic therapy for the eligible elderly patient, persistent concerns regarding the risk of intracranial hemorrhage impedes utilization in this age group. Primary or direct angioplasty of the infarct artery has been proven to be an effective modality for reperfusion. Randomized comparisons suggest an advantage over thrombolysis in terms of achieving superior patency and mitigating recurrent ischemic events. Primary angioplasty expands the reperfusion population by including many patients ineligible for thrombolysis and is more effective for treating patients at high risk, such as those with cardiogenic shock. Acute angiography accumulates important prognostic and decision-facilitating information. The benefits of primary angioplasty are more impressive for the aging patient. The survival gain and reduction in intracranial hemorrhage may combine to magnify the advantages of performing angioplasty on patients in this group. Emerging evidence concerning the aging population validates continued examination of this invasive reperfusion approach.

Thrombolytic therapy can reduce the arrhythmogenic substrate after acute myocardial infarction: a study using the signal-averaged electrocardiogram, endocardial catheter mapping and programmed ventricular stimulation

Thrombolytic therapy improves survival after acute myocardial infarction (AMI) primarily by preserving left ventricular function. Its influence on the arrhythmogenic substrate remains uncertain. To investigate the electrophysiologic effects of thrombolytic therapy, signal-averaged electrocardiography, endocardial catheter mapping and programmed stimulation were performed in 93 consecutive patients with their first AMI who underwent thrombolytic therapy. Early reperfusion was achieved in 75 patients (group 1), but not in 18 patients (group 2). The incidence of the signal-averaged electrocardiogram abnormality was 11% in group 1 (8 of 75 patients) and 33% in group 2 (6 of 18 patients) (p<0.02). Catheter mapping detected delayed endocardial electrograms in 30 group 1 patients and 10 group 2 patients (p=NS). The spatial distribution of these electrograms was smaller, and the longest duration of endocardial electrograms was shorter in group 1 than in group 2 (p<0.01). Sustained monomorphic ventricular tachycardia was induced less commonly in group 1 (20%) than in group 2 (44%) (p<0.05). In conclusion, thrombolytic therapy can reduce the arrhythmogenic substrate and improve electrical stability after AMI. This antiarrhythmic effect may contribute, in part, to the improved survival of patients treated with thrombolytic drugs.

Limitation of myocardial infarct size after primary angioplasty: is a higher patency the only mechanism?

BACKGROUND

Several studies demonstrate a better outcome after primary angioplasty compared with thrombolysis. The mechanism is assumed to be a higher rate of open infarct-related vessels.

METHODS AND RESULTS

We conducted a randomized trial of primary coronary angioplasty compared with thrombolysis. A total of 401 patients with acute myocardial infarction were randomly assigned to either primary angioplasty or thrombolytic therapy. Radionuclide left ventricular ejection fraction was performed before hospital discharge. Infarct size was estimated by measurement of serial lactate dehydrogenase activity (LDH Q72). Separate analyses were performed in patients with an open infarct-related vessel, either after thrombolysis or angioplasty. Baseline characteristics were comparable between the 2 treatment groups. Of the 197 patients treated with angioplasty, 176 (89%) had an open infarct-related vessel compared with 126 (62%) of the 204 patients treated with thrombolysis (P <.001). In patients with an open infarct-related vessel, those treated with primary angioplasty had a lower enzyme release compared with those treated with thrombolysis: LDH Q72 949 (748) and 1200 (1117), respectively (P <.05). Compared with angioplasty, patients treated with thrombolysis had a lower left ventricular ejection fraction. In the subgroup of patients with an open infarct-related vessel, after thrombolysis or angioplasty, patients treated with thrombolysis still had a lower ejection fraction (47% vs 50%, P <.05). Multivariate analysis, adjusting for differences in several clinical variables, did not change these results. Patients with an open infarct-related vessel and thrombolysis had a higher risk of an ejection fraction <40% compared with patients treated with primary angioplasty (relative risk 1.9, 95% confidence interval 1.0 to 2.7).

CONCLUSIONS

Despite successful thrombolysis, with sustained patency of the infarct-related vessel, primary angioplasty remains superior to thrombolytic therapy with regard to left ventricular function and enzymatic infarct size. This may be caused by adverse effects of fibrinolytics on infarcted myocardium.

Percutaneous transluminal coronary angioplasty, alone or in combination with urokinase therapy, during acute myocardial infarction

To investigate the effect of pre-treatment of a thrombus with a low dose of urokinase on establishing patency in a persistent infarct-related artery (IRA) during direct percutaneous coronary angioplasty (PTCA), the frequency of acute restenosis during direct PTCA, alone, or in combination with the intracoronary administration of urokinase, was examined in a consecutive nonrandomized series of patients with acute myocardial infarction (AMI). Two hundred and seventy-two successful PTCA patients (residual stenosis <50%) were divided into 2 groups: 88 patients received pre-treatment with intracoronary urokinase following PTCA (combination group); 184 received only direct PTCA without thrombolytic therapy (PTCA group). In the present study, after achievement of a residual stenosis of less than 50%, IRA was visualized every 15 min to assess the frequency of acute restenosis, which was defined as an acute progression of IRA with more than 75% restenosis after initially successful PTCA. In the patients with a large coronary thrombus, the frequency (times) of acute restenosis was significantly lower in the combination group than in the PTCA group (0.98+/-0.19 vs 2.92+/-0.32, p<0.0001). On the other hand, in the patients with a small coronary thrombus, the frequency of acute restenosis showed no difference in either group. The present study indicates that in patients with AMI, PTCA combined with pre-treatment of a low dose of urokinase is much more effective than PTCA alone, especially for those patients who have a large coronary thrombus.

Fatal cardiac rupture among patients treated with thrombolytic agents and adjunctive thrombin antagonists: observations from the Thrombolysis and Thrombin Inhibition in Myocardial Infarction 9 Study

OBJECTIVES

The purpose of this study was to determine the incidence and demographic characteristics of patients experiencing cardiac rupture after thrombolytic and adjunctive anticoagulant therapy and to identify possible associations between the mechanism of thrombin inhibition (indirect, direct) and the intensity of systemic anticoagulation with its occurrence. BACKGROUND Cardiac rupture is responsible for nearly 15% of all in-hospital deaths among patients with myocardial infarction (MI) given thrombolytic agents. Little is known about specific patient- and treatment-related risk factors. METHODS Patients (n = 3,759) with MI participating in the Thrombolysis and Thrombin Inhibition in Myocardial Infarction 9A and B trials received intravenous thrombolytic therapy, aspirin and either heparin (5,000 U bolus, 1,000 to 1,300 U/h infusion) or hirudin (0.1 to 0.6 mg/kg bolus, 0.1 to 0.2 mg/kg/h infusion) for at least 96 h. A diagnosis of cardiac rupture was made clinically in patients with sudden electromechanical dissociation in the absence of preceding congestive heart failure, slowly progressive hemodynamic compromise or malignant ventricular arrhythmias. RESULTS A total of 65 rupture events (1.7%) were reported-all were fatal, and a majority occurred within 48 h of treatment Patients with cardiac rupture were older, of lower body weight and stature and more likely to be female than those without rupture (all p < 0.001). By multivariable analysis, age >70 years (odds ratio [OR] 3.77; 95% confidence interval [CI] 2.06, 6.91), female gender (OR 2.87; 95% CI 1.44, 5.73) and prior angina (OR 1.82; 95% CI 1.05, 3.16) were independently associated with cardiac rupture. Independent predictors of nonrupture death included age >70 years (OR 3.68; 95% CI 2.53, 5.35) and prior MI (OR 2.14; 95%, CI 1.45, 3.17). There was no association between the type of thrombin inhibition, the intensity of anticoagulation and cardiac rapture. CONCLUSIONS Cardiac rupture following thrombolytic therapy tends to occur in older patients and may explain the disproportionately high mortality rate among women in prior dinical trials. Unlike major hemorrhagic complications, there is no evidence that the intensity of anticoagulation associated with heparin or hirudin administration influences the occurrence of rupture.

Long-term prognostic significance of ventricular late potentials after a first acute myocardial infarction

Ventricular late potentials (VLP) have been shown to be independent predictors of arrhythmic events after myocardial infarction. However, many studies have had one or more limitations: limited follow-up period, small study group, possible selection bias, inadequate statistical analysis, or inclusion of patients with previous infarction. The purpose of this study was to assess the long-term prognostic value of VLP in a large group of unselected patients after a first acute myocardial infarction. Time-domain signal averaging was performed in 458 patients (380 male, 78 female, mean age 59 +/- 11 years) a mean of 10 days (range 7 to 13 days) after a first acute myocardial infarction. The overall prevalence of VLP was 20% (90 of 458 patients). By univariate analysis a left ventricular ejection fraction <40% (p = 0.002) and the presence of an occluded infarct-related artery (p = 0.006) were the only statistically significant predictors for the development of VLP. During a median follow-up of 70 months, 21 (5%) patients died suddenly, and 11 (2%) patients had documented sustained ventricular tachycardia. The presence of VLP (p < 0.0001), older age (p = 0.02), and an occluded infarct-related artery (p = 0.045) were the only variables significantly associated with the occurrence of serious arrhythmic events during follow-up. The probability of having no arrhythmic events was 99% at 1 year and 96% at 5 years in the absence of VLP and 87% at 1 year and 80% at 5 years in the presence of VLP (4.6-fold increase in arrhythmic risk; 95% confidence interval: 2.3 to 9.1). VLPs are powerful predictors of serious arrhythmic events in patients after a first acute myocardial infarction, and their prognostic value, although waning with time, persists for at least 7 years. This study also provides further evidence that an open infarct-related artery may reduce the arrhythmic risk after myocardial infarction.

Primary angioplasty reduces risk of myocardial rupture compared to thrombolysis for acute myocardial infarction

Although the mechanical complications of acute ventricular septal defect and acute mitral regurgitation are uncommon after acute myocardial infarction, these complications are associated with an extremely high morbidity and mortality. We hypothesized that the administration of thrombolytic drugs may result in hemorrhagic infarction as well as the potential for incomplete revascularization and thus may lead to an increased incidence of mechanical complications compared to primary angioplasty. Accordingly, we reviewed the data of the most contemporary thrombolytic and primary angioplasty trials and compared the incidence of mechanical complications among 36,303 patients treated with thrombolytics reported in the GUSTO trial to the incidence of mechanical complications among 1,295 patients treated with primary angioplasty obtained from the PAMI-1 and PAMI-2 trials. We found that angioplasty resulted in an overall 86% relative risk reduction in mechanical complications (2.20% vs. 0.31%, P < 0.001). In comparison to thrombolytic therapy, angioplasty resulted in an 82% decrease in acute mitral regurgitation (1.73% vs. 0.31%, P < 0.001) and a 100% decrease in acute ventricular septal defect (0.47% vs. 0.00%, P < 0.03). In conclusion, in patients with acute myocardial infarction, reperfusion with primary angioplasty is associated with less myocardial rupture and mechanical complications than thrombolytics. This finding may, in part, explain the improved prognosis observed in myocardial infarction patients treated with primary angioplasty.

Relationship between progressive microvascular damage and intramyocardial hemorrhage in patients with reperfused anterior myocardial infarction: myocardial contrast echocardiographic study

BACKGROUND

Recent studies indicated that ischemic microvascular damage may be reversible or progressive after coronary reflow. Intramyocardial hemorrhage is a phenomenon that reflects severe microvascular injury. We examined the relationship between temporal changes in microvascular perfusion patterns detected by myocardial contrast echocardiography (MCE) and intramyocardial hemorrhage detected by magnetic resonance imaging (MRI) in patients with acute myocardial infarction (AMI).

METHODS AND RESULTS

The study population consisted of 24 patients with anterior AMI. All patients underwent MCE shortly after reflow and in the chronic stage (a mean of 31 days after reflow). Wall motion score (WMS) was determined as the sum of 16 segmental scores (dyskinetic/akinetic=3 to normal=0) at days 1 and 31. Gradient-echo acquisition and gadolinium-DTPA-enhanced spin-echo MRI were performed within 10 days after reflow. In MCE shortly after reflow, 16 patients (67%) showed contrast enhancement and the other 8 patients (33%) showed a sizable contrast defect. In the chronic stage, a persistent contrast defect was observed in 7 of 8 patients with a contrast defect shortly after reflow. Consistent contrast enhancement was observed in 12 of 16 patients (75%) with contrast enhancement shortly after reflow, indicating that a contrast defect newly appeared in 4 patients (25%). Intramyocardial hemorrhage was detected in 9 patients (38%): 5 of 7 patients with a persistent contrast defect and in all 4 patients with a new appearance of a contrast defect during the chronic stage. The patients without hemorrhage showed a significant improvement in WMS compared with patients with hemorrhage at day 31 (5+/-5 versus 19+/-6, P<.0005).

CONCLUSIONS

These results suggest that irreversible microvascular damage to the ischemic myocardium may cause intramyocardial hemorrhage after reflow, associated with impaired recovery of left ventricular function. Contrast enhancement within the risk area shortly after reflow does not necessarily indicate long-term microvascular salvage.

Infarct size, myocardial hemorrhage, and recovery of function after mechanical versus pharmacological reperfusion: effects of lytic state and occlusion time

BACKGROUND

Whether myocardial reperfusion obtained with thrombolysis or primary angioplasty is associated with a similar recovery of function and with the same risk of hemorrhagic infarction is unknown. We evaluated the effects of mechanical and pharmacological reperfusion (with or without a plasma lytic state) on infarct size, myocardial hemorrhage, and left ventricular (LV) function in a canine model.

METHODS AND RESULTS

Six groups of six dogs were subjected to balloon occlusion of the left anterior descending coronary artery (LAD) followed by 2 hours of reperfusion. The study had a two-by-three factorial design with two occlusion periods (90 and 240 minutes) and three different reperfusion strategies (placebo, 0.4 mg/kg recombinant tissue plasminogen activator, and 40 microg/kg recombinant staphylokinase). In a seventh control group, LAD occlusion was maintained without reperfusion. All dogs received aspirin and heparin. A systemic lytic state was present in staphylokinase-treated dogs. Planimetry of LV slices showed larger infarcts (percent of area at risk) and more hemorrhage (percent of IA) after 240 minutes of occlusion than after 90 minutes of occlusion (54+/-17% versus 37+/-18% and 52+/-27% versus 29+/-27%, respectively; P<.01 for both comparisons), with no significant difference among treatments. Hemorrhage was not observed in the control group without reperfusion. LV angiography showed no differences in global and regional LV function between mechanical and pharmacological reperfusion.

CONCLUSIONS

In this experimental model, hemorrhagic infarctions of similar extent were observed after both pharmacological and mechanical reperfusion. The extent of hemorrhage was increased by the delay in reperfusion but not by the presence of a lytic state.

Timing and mechanism of death determined clinically after primary angioplasty for acute myocardial infarction

We reviewed the timing and mechanism of death in 1,184 consecutive patients with acute myocardial infarction (AMI) treated with primary angioplasty from 1984 to 1995. Of 98 deaths, 48 (49%) occurred early on day 0 or 1. The mechanisms of death were pump failure in 60 patients (61%), reinfarction in 7 patients (7.1%), left ventricular rupture in 5 patients (5.1%), arrhythmia in 3 patients (3.1%), other cardiac causes in 5 patients (5.1%), stroke in 6 patients (6.1%), anoxic encephalopathy in 7 patients (7.1%), and procedure-related deaths in 5 patients (5.1%). The strongest predictors of mortality were cardiogenic shock and unsuccessful reperfusion. Our data indicate that mortality after primary angioplasty, like thrombolytic therapy, is highest in the early hours and is usually due to pump failure. In contrast to thrombolytic therapy, the incidence of death from myocardial rupture and bleeding complications is low. Future treatment strategies will need to focus on the large number of patients with early death due to pump failure, especially patients with cardiogenic shock.

Coronary artery and saphenous vein graft remodeling: a review of histologic findings after various interventional procedures--Part IV

Catheter balloon angioplasty is a well accepted form of nonsurgical treatment of acutely and chronically obstructed coronary artery vessels. It is also the centerpiece for various new intervention techniques. Their morphologic effects on the site of obstruction has been termed "remodeling." Part IV of this six-part series focuses on morphologic correlates of coronary angiographic patterns of remodeling after balloon angioplasty and discusses effects of angioplasty on adjacent, nondilated vessels.

Results of percutaneous transluminal coronary angioplasty in unstable angina and non-Q-wave myocardial infarction. Observations from the TIMI IIIB Trial

BACKGROUND

This report describes the results of percutaneous transluminal coronary angioplasty (PTCA) in the Thrombolysis in Myocardial Ischemia (TIMI) IIIB Investigation.

METHODS AND RESULTS

PTCA was performed before hospital discharge in 444 of 1473 patients with either unstable angina pectoris or non-Q-wave myocardial infarction (NQWMI) enrolled in TIMI IIIB. Angiographic success was observed in 96.1% of patients. For the entire cohort, the cumulative incidences of death and infarction at 1 year were 2.0% and 8.2%, respectively. The periprocedural incidence of myocardial infarction was 2.7%; emergency coronary bypass surgery, 1.4%; and death, 0.5%. By 1 year of follow-up, 122 patients (28.0%, Kaplan-Meier) had an additional revascularization procedure, 75 (61.5%) had PTCA only, 30 (24.6%) had coronary bypass surgery only, and 17 (13.9%) had both procedures. The results of PTCA were not improved by routine pretreatment with intravenous tissue plasminogen activator (TPA). Periprocedural myocardial infarction was more common among patients receiving TPA than placebo (odds ratio [OR], 2.19; P = .03) and among those with unstable angina than those with NQWMI (OR, 15.5; P = .007). No difference in outcome was observed when patients were analyzed according to age (OR, 1.06; P = .092) or sex (OR, 1.54; P = .51). Variables predictive of poor outcome were PTCA within the first 24 hours of enrollment, PTCA site being the left anterior descending coronary artery, and unsuccessful angiography.

CONCLUSIONS

In TIMI IIIB, PTCA was performed for patients with unstable angina and NQWMI with a very high rate of angiographic success and a low incidence of complications. By 1 year, repeat revascularization was performed in 28.0% of patients. Routine pretreatment with thrombolysis did not enhance outcome.

Abrupt (< 1 day), acute (< 1 week), and early (< 1 month) vessel closure at the angioplasty site. Morphologic observations and causes of closure in 130 necropsy patients undergoing coronary angioplasty

While abundant clinical and angiographic data are available regarding features of acute or abrupt closure at the site of balloon angioplasty, little morphologic information is available. This study discusses morphologic-histologic causes for acute closure after angioplasty in 130 necropsy patients. Intimal-medial flaps, elastic recoil, and primary thrombosis were the three leading morphologic causes for closure. Data were subdivided into time categories: abrupt (< 1 day), acute (< 1 week), and early (< 1 month). Intimal-medial flaps remained the most common cause for angioplasty closure despite time from angioplasty to documented occlusion. Morphologic recognition of types and frequencies of angioplasty closure are discussed, and specific mechanical, pharmacologic, or combined treatments are reviewed.

Coronary artery and saphenous vein graft remodeling: a review of histologic findings after various interventional procedures--Part II

Catheter balloon angioplasty is a well accepted form of nonsurgical treatment of acutely and chronically obstructed coronary artery vessels. It is also the centerpiece for various new intervention techniques. Their morphologic effects on the site of obstruction has been termed "remodeling." Part II of this six-part series focuses on morphologic causes of acute closure after remodeling and discusses findings late after successful balloon angioplasty remodeling.

Use of c7E3 Fab in conjunction with primary coronary stenting for acute myocardial infarctions complicated by cardiogenic shock

Although use of thrombolytic therapy during primary angioplasty is controversial, the development of a monoclonal antibody (c7E3 Fab) to the platelet glycoprotein IIb/IIIa receptor has been a tremendous breakthrough in the field of interventional cardiology. Use of the antibody during high-risk angioplasty or atherectomy procedures has been shown to significantly reduce the incidence of death, MI, or emergent repeat revascularization. We describe four cases in which c7E3 Fab was used as an adjunct to coronary stenting in the peri-infarct period in patients with cardiogenic shock. To our knowledge, no other reports have addressed the use of glycoprotein IIb/IIIa receptor inhibitors with coronary stent implantation. Our experience in this small population suggests that coronary stenting for myocardial infarctions may be a feasible option in selected patients to allow maximal luminal dilation and successful reperfusion. We emphasize that our results are preliminary, and we eagerly await the results of the EPILOG study which will provide more definitive data on the safety and efficacy of c7E3 Fab and coronary stenting from the perspective of a large, randomized trial.

Coronary artery and saphenous vein graft remodeling: a review of histologic findings after various interventional procedures--Part I

Catheter balloon angioplasty is a well accepted form of nonsurgical treatment of acutely and chronically obstructed coronary artery vessels. It is also the centerpiece for various new intervention techniques. Their morphologic effects on the site of obstruction has been termed "remodeling." Part I of this six-part series focuses on mechanisms of remodeling after various interventional techniques, particularly balloon angioplasty.

Adjunctive intracoronary urokinase therapy during percutaneous transluminal coronary angioplasty

Uncontrolled studies have suggested that intracoronary urokinase may be beneficial in patients undergoing percutaneous transluminal coronary angioplasty (PTCA). Therefore, 280 consecutive patients undergoing PTCA were prospectively randomized to receive a bolus injection of 12,500 U of heparin followed by a continuous intracoronary infusion via the guiding catheter of either 250 U heparin per minute or 250 U heparin plus 5,000 U urokinase per minute during the procedure. Procedural success rates (<50% final diameter stenosis by quantitative angiography and no major ischemic complications during in-hospital follow-up) were similar, with 87% in the heparin group (n=135) and 86% in the heparin plus urokinase group (n=127). Percent diameter stenosis after PTCA was 39 +/- 12% in the heparin group plus urokinase group (p=NS). There were no difference between groups with respect to PTCA-related acute vessels occlusion, angiographic evidence of intracoronary thrombus formation, creatine kinase increase after the procedure, Q-wave myocardial infarction, or emergency coronary artery bypass surgery. High-risk subgroup analysis revealed no beneficial effect of adjunctive intracoronary urokinase in patients with acute coronary insufficiency syndromes (n=86) or in stenoses with an irregular luminal contour (n=134). In addition, although risk stratification according to the criteria of the American College of Cardiology/American Heart Association Task Force classification proved to be very useful for the entire study population, no beneficial effect of intracoronary urokinase infusion was observed in any of the different risk groups. Thus, compared with heparin alone, adjunctive intracoronary urokinase therapy does not appear to have any beneficial effect upon procedural outcome or on type and frequency of acute complications during PTCA, even in subgroups of patients with high risk for thrombotic complications.