Direct stenting versus stenting after predilatation in STEMI patients with high thrombus burden: a subanalysis from the randomized COMPARE CRUSH trial

Background/Introduction

Direct stenting has been proposed to reduce vessel wall damage and distal embolization in patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI). However, studies comparing direct stenting with stenting after predilatation have shown mixed results so far. Patients presenting with high thrombus burden in the culprit lesion represent a subgroup of STEMI patients that may particularly benefit from direct stenting, as high thrombus burden is associated with suboptimal reperfusion and poor clinical outcomes.

Purpose

We sought to determine the efficacy of direct stenting compared with stenting after predilatation in STEMI patients presenting with high thrombus burden.

Methods

The randomized COMPARE CRUSH trial assessed the efficacy of pre-hospital administration of crushed versus integral prasugrel tablets in patients presenting with STEMI planned for primary PCI. We assessed Thrombolysis In Myocardial Infarction (TIMI) flow, corrected TIMI frame count (cTFC) and myocardial blush grade at the end of primary PCI, as well as the occurrence of complete (≥70%) ST-segment resolution 1 hour post-PCI in STEMI patients presenting with high thrombus burden in the culprit lesion (defined as a TIMI thrombus grade ≥3).

Results

A total of 417 STEMI patients were included in the current analysis of which 336 (81%) presented with high thrombus burden on initial angiography with 144 patients (43%) being treated with direct stenting. Patients undergoing direct stenting exhibited significantly lower cTFC post-PCI compared with stenting after predilatation (16 [12–24] vs. 20 [13–29], p=0.02). Moreover, direct stenting patients more frequently exhibited complete ST-segment resolution 1 hour post-PCI compared with stenting after predilatation (72% vs. 59%, OR 1.82 [95% CI, 1.11–2.99], p=0.02). In contrast, we found no differences in the occurrence of TIMI 3 flow (DS 92% vs. 92%, OR 1.02 [0.47–2.22], p=0.97) or myocardial blush grade 3 (DS 63% vs. 54%, OR 1.45 [95% CI, 0.83–2.52], p=0.19) post-PCI between groups.

Conclusion

STEMI patients presenting with high thrombus burden treated with direct stenting showed improved markers of early myocardial reperfusion compared with patients treated with stenting after predilatation, indicating that a direct stenting strategy may benefit the subgroup of STEMI patients that present with high thrombus burden. Randomized trials are warranted to further investigate whether the potential benefits of direct stenting outweigh potential hazards over the long-term.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): Daiichi-Sankyo and Shanghai MicroPort Medical

Platelet reactivity and bleeding outcomes in female patients presenting with ST-segment elevation myocardial infarction: a COMPARE CRUSH substudy

Background/Introduction

Females presenting with ST-segment elevation myocardial infarction (STEMI) are characterized by an increased risk of bleeding after primary percutaneous coronary intervention (pPCI) compared with males. The reason for increased bleeding rates is multifactorial, including age, comorbidities, vessel anatomy and possible differences in platelet biology. Data about platelet reactivity levels in females versus males presenting with STEMI is scarce.

Purpose

Investigation of gender-driven variances in platelet reactivity and bleeding outcomes in STEMI patients planned to undergo pPCI.

Methods

The COMPARE CRUSH trial was a randomized multicenter ambulance trial assessing the effect of prehospital administration of P2Y12 inhibitor loading dose with crushed versus integral prasugrel tablets in STEMI patients. We assessed the occurrence of high platelet reactivity (HPR), predictors of HPR at baseline and bleeding outcomes between females and males. Blood samples were analyzed at four prespecified time points using VerifyNow.

Results

The COMPARE CRUSH trial included 633 STEMI patients in the period between November 2017 and March 2020. Females more frequently exhibited HPR at baseline than males (76% vs. 41%, odds ratio (OR), 4.58 [95% CI, 2.52 to 8.32], p<0.01). Moreover, female sex was a strong, independent predictor for HPR at baseline (OR, 4.93 [95% CI, 2.30 to 10.57], p<0.01). HPR rates at other time points were not significantly different between females and males. The risk of bleeding within the first 48 hours was significantly increased in females (OR, 6.02 [95% CI, 2.58 to 14.08], p<0.01), but after adjustment for baseline characteristics this increased risk was no longer statistically significant (OR, 2.61 [95% CI, 0.73 to 9.32], p=0.14).

Conclusion

Female sex is an independent predictor for occurrence of HPR at baseline in STEMI patients. However, females exhibit a stronger platelet inhibition effect by oral P2Y12 inhibitors than males, which may contribute to an increased bleeding risk. A more tailored antiplatelet therapy approach should be considered for female STEMI patients to reduce bleeding risk.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): Unrestricted grants from Daiichi-Sankyo and Shanghai MicroPort Medical.

P1022Upstream therapy using preoperative renin-angiotensin system inhibitors in prevention of postoperative atrial fibrillation and adverse events: a collaborative pooled-analysis over 27,000 patients

Background

Renin-angiotensin-system inhibitors (RASIs) have been suggested as an upstream therapy for selected AF patients; however, the evidence in surgical setting is limited.

Objective

We aimed to evaluate the role of preoperative RASIs in prevention of postoperative atrial fibrillation (POAF) and adverse events for patients undergoing cardiac surgery.

Methods

In this collaborative pooled-analysis, both randomized and nonrandomized controlled trials comparing preoperative RASIs with no preoperative RASIs treatment on the incidence of POAF were identified. Sensitivity and subgroup analyses of RCTs were performed to test the stability of the overall-effect, and meta-regression to explore the potential risk of bias. The primary outcome was POAF, and the secondary outcomes includes rate of stroke, mortality and duration of hospitalization.

Results

Eleven trials involving 27885 patients (male 74%, median age 65yrs) were included. As compared to the control group, preoperative RASIs did not significantly reduce the risk of POAF (OR: 1.04, 95% CI: 0.91–1.19), stroke (OR: 0.86, 95% CI: 0.62–1.19), death (OR: 1.07, 95% CI: 0.85–1.35), composite adverse cardiac events (OR: 1.04, 95% CI: 0.91–1.18), and hospital stay (WMD: −0.04, 95% CI: −1.05 to 0.98). Pooled-analysis of randomized trials showed consistent results. The primary overall-effect was maintained in sensitivity and subgroup analyses. Meta-regression showed that male-gender was a significant risk-factor of POAF and use of Beta-blockers was associated with a significantly reduced risk in developing POAF.

Conclusion and relevance

This study demonstrates that preoperative RASIs do not offer additional benefit in reducing the risk of postoperative AF, stroke, death and hospitalization in the setting of cardiac surgery. The results provide no support for use of RASIs for the prevention of POAF and adverse events in patients undergoing cardiac surgery.

Infarct size and left ventricular function in the PRoximal Embolic Protection in Acute myocardial infarction and Resolution of ST-segment Elevation (PREPARE) trial: ancillary cardiovascular magnetic resonance study

OBJECTIVES

The aim of the study was to evaluate whether primary percutaneous coronary intervention (PCI) with combined proximal embolic protection and thrombus aspiration results in smaller final infarct size and improved left ventricular function assessed by cardiovascular magnetic resonance (CMR) in ST-segment elevation myocardial infarction (STEMI) patients compared with primary PCI alone. Background Primary PCI with the Proxis system improves immediate microvascular flow post-procedure as measured by ST-segment resolution, which could result in better outcomes.

METHODS

The ancillary CMR study included 206 STEMI patients who were enrolled in the PRoximal Embolic Protection in Acute myocardial infarction and Resolution of ST-Elevation (PREPARE) trial. CMR imaging was assessed between 4 and 6 months after the index procedure.

RESULTS

There were no significant differences in final infarct size (6.1 g/m(2) vs 6.3 g/m(2), p = 0.78) and left ventricular ejection fraction (50% vs 50%, p = 0.46) between both groups. Also, systolic wall thickening in the infarct area (44% vs 45%, p = 0.93) or the extent of transmural segments (8.3% of segments vs 8.3% of segments, p = 0.60) showed no significant differences. The incidence of major adverse cardiac and cerebral events at 6 months was similar in the Proxis and control group (8% vs 10%, respectively, p = 0.43). Conclusions Primary PCI with combined proximal embolic protection and thrombus aspiration in STEMI patients did not result in significant differences in final infarct size or left ventricular function at follow-up CMR. In addition, there was no difference in the incidence of major adverse cardiac and cerebral events at 6 months.

TRIAL REGISTRATION

number ISRCTN71104460.

Slowed ST segment recovery despite early infarct artery patency in patients with Q waves at presentation with a first acute myocardial infarction. Implications of initial Q waves on myocyte reperfusion

BACKGROUND

The presence of Q waves at presentation with a first acute myocardial infarction reflects a more advanced stage of the infarction process. When infarct-related artery patency (Thrombolysis in Myocardial Infarction 2 or 3 flow) is restored, resolution of ST segment elevation indicating successful myocyte reperfusion may differ according to how far the infarction process has progressed.

METHODS AND RESULTS

In 144 patients with a first acute myocardial infarction treated with streptokinase in the first Hirulog Early Reperfusion Occlusion trial, information was obtained from continuous ST segment monitoring, the presenting electrocardiogram and early angiography performed at a median time of 99 min after the commencement of streptokinase (interquartile range 89-108 min). We determined how many patients had 50% ST recovery within 120 min and in how many cases it was sustained over 4h. In the 109 patients with patent infarct-related arteries, 50% ST recovery occurred in 95% of patients without vs 80% of those with initial Q waves (P=0.03), and sustained ST recovery occurred in 67% of patients without vs 47% of those with initial Q waves (P=0.03). On multivariate analysis including the time from symptom onset to streptokinase therapy, the presence of Q waves at presentation was the only predictor of failure to achieve 50% ST recovery (odds ratio 5.08, 95% confidence interval 1.29-20.01, P=0.02). TIMI 2 flow, as opposed to TIMI 3 flow, was the only predictor of failure to achieve stable ST recovery (odds ratio 2.63, 95% confidence interval 1.15-5.88,P =0.02).

CONCLUSION

The presence of initial Q waves predicts slower and less complete ST recovery, reflecting reduced myocyte reperfusion, even in those with early infarct artery patency. These patients may be targeted for new therapeutic strategies to improve microvascular reperfusion.

Integrative noetic therapies as adjuncts to percutaneous intervention during unstable coronary syndromes: Monitoring and Actualization of Noetic Training (MANTRA) feasibility pilot

BACKGROUND

Patients undergoing percutaneous coronary intervention (PCI) for unstable coronary syndromes have substantial emotional and spiritual distress that may promote procedural complications. Noetic (nonpharmacologic) therapies may reduce anxiety, pain and distress, enhance the efficacy of pharmacologic agents, or affect short- and long-term procedural outcomes.

METHODS

The Monitoring and Actualization of Noetic Training (MANTRA) pilot study examined the feasibility of applying 4 noetic therapies-stress relaxation, imagery, touch therapy, and prayer-to patients in the setting of acute coronary interventions. Eligible patients had acute coronary syndromes and invasive angiography or PCI. Patients were randomized across 5 treatment groups: the 4 noetic and standard therapies. Questionnaires completed before PCI reflected patients' religious beliefs and anxiety. Index hospitalization end points included post-PCI ischemia, death, myocardial infarction, heart failure, and urgent revascularization. Mortality was followed up for 6 months after hospitalization.

RESULTS

Of eligible patients, 88% gave informed consent. Of 150 patients enrolled, 120 were assigned to noetic therapy; 118 (98%) completed their therapeutic assignments. All clinical end points were available for 100% of patients. Results were not statistically significant for any outcomes comparisons. There was a 25% to 30% absolute reduction in adverse periprocedural outcomes in patients treated with any noetic therapy compared with standard therapy. The lowest absolute complication rates were observed in patients assigned to off-site prayer. All mortality by 6-month follow-up was in the noetic therapies group. In patients with questionnaire scores indicating a high level of spiritual belief, a high level of personal spiritual activity, a low level of community-based religious involvement, or a high level of anxiety, noetic therapies appeared to show greater reduction in absolute in-hospital complication rates compared with standard therapy.

CONCLUSIONS

Acceptance of noetic adjuncts to invasive therapy for acute coronary syndromes was excellent, and logistics were feasible. No outcomes differences were significant; however, index hospitalization data consistently suggested a therapeutic benefit with noetic therapy. Of all noetic therapies, off-site intercessory prayer had the lowest short- and long-term absolute complication rates. Definitive demonstration of treatment effects of this magnitude would be feasible in a patient population about 4 times that of this pilot study. Absolute mortality differences make safety considerations a mandatory feature of future clinical trials in this area.

Association of noninvasive markers of coronary artery reperfusion to assess microvascular obstruction in patients with acute myocardial infarction treated with primary angioplasty

Early restoration of coronary artery patency through primary angioplasty limits infarct size and improves survival. Increasing evidence, however, suggests that microvascular obstruction is often present despite coronary artery recanalization. This may limit the benefits of reperfusion therapy. We studied the use of noninvasive markers of coronary artery reperfusion as indicators of microvascular obstruction and determinants of prognosis in 98 patients with acute myocardial infarction (AMI) who were successfully treated with primary angioplasty (Thrombolysis In Myocardial Infarction grade 3 flow and residual stenosis <30%). Plasma creatine kinase (CK) levels and 12-lead electrocardiograms were performed on admission, at 90 minutes, and at 6, 12, and 24 hours after treatment. We defined: (1) reperfusion as resolution of ST-segment elevation >50% at 90 minutes, with peak CK levels within 12 hours, and T-wave inversion within 24 hours; and (2) failed reperfusion, as the absence of these parameters. Of the 98 patients studied, 87 (88.8%) had reperfusion and 11 (11.2%) had failed reperfusion. Infarct location was anterior (versus inferior) in 9 patients in the failed reperfusion group (81.8%) compared with 41 patients in the reperfusion group (47.1%) (p <0.01). Congestive heart failure >24 hours after presentation or in-hospital death occurred in 11 patients (12.6%) in the reperfusion group versus 5 (45.5%) in the failed reperfusion group (p <0.01). One-year survival was 96.1% for the reperfusion group and 60.6% for the failed reperfusion group (p <0.0001). We conclude that the association of noninvasive markers of reperfusion better identifies patients with microvascular obstruction among those who had a "successful" primary angioplasty. Evidence of impaired microvascular reperfusion is associated with a poor in-hospital and 1-year outcome.

Shifting the open-artery hypothesis downstream: the quest for optimal reperfusion

Successful reperfusion after acute myocardial infarction (MI) has traditionally been considered to be restoration of epicardial patency, but increasing evidence suggests that disordered microvascular function and inadequate myocardial tissue perfusion are often present despite infarct vessel patency. Thus, optimal reperfusion is being redefined to include intact microvascular flow and restored myocardial perfusion, as well as sustained epicardial patency. Coronary angiography has been used as the gold standard to define failed reperfusion, according to the Thrombolysis In Myocardial Infarction (TIMI) flow grades. However, new angiographic techniques, including the corrected TIMI frame count and myocardial blush grade, have been used to show that epicardial TIMI flow grade 3 may be an incomplete measure of reperfusion success. Furthermore, evolving noninvasive diagnostic techniques, including measurement of infarct size with cardiac marker release patterns or technetium-99m-sestamibi single-photon emission computed tomographic imaging and analysis of ST segment resolution appear to be useful complements to angiography for the assessment of myocardial tissue reperfusion. Promising adjunctive therapies that target microvascular dysfunction, including platelet glycoprotein IIb/IIIa inhibitors, and agents designed to improve tissue perfusion and attenuate reperfusion injury are being evaluated to further improve clinical outcomes after acute MI. To accelerate development of these new reperfusion regimens, an integrated approach to phase II clinical trials that incorporates multiple efficacy variables, including angiography and noninvasive biomarkers of microvascular dysfunction, should be considered. Thus, as the reperfusion era moves into the next millennium, the open-artery hypothesis is expected to shift downstream and guide efforts to further improve myocardial salvage and clinical outcomes after acute MI.

A randomized trial of the effects of early cardiac serum marker availability on reperfusion therapy in patients with acute myocardial infarction: the serial markers, acute myocardial infarction and rapid treatment trial (SMARTT)

OBJECTIVES

The purpose of this study was to assess whether the immediate availability of serum markers would increase the appropriate use of thrombolytic therapy.

BACKGROUND

Serum markers such as myoglobin and creatine kinase, MB fraction (CK-MB) are effective in detecting acute myocardial infarction (AMI) in the emergency setting. Appropriate candidates for thrombolytic therapy are not always identified in the emergency department (ED), as 20% to 30% of eligible patients go untreated, representing 10% to 15% of all patients with AMI. Patients presenting with chest pain consistent with acute coronary syndrome were evaluated in the EDs of 12 hospitals throughout North America.

METHODS

In this randomized, controlled clinical trial, physicians received either the immediate myoglobin/CK-MB results at 0 and 1 h after enrollment (stat) or conventional reporting of myoglobin/CK-MB 3 h or more after hospital admission (control). The primary end point was the comparison of the proportion of patients within the stat group versus control group who received appropriate thrombolytic therapy. Secondary end points included the emergent use of any reperfusion treatment in both groups, initial hospital disposition of patients (coronary care unit, monitor or nonmonitor beds) and the proportion of patients appropriately discharged from the ED.

RESULTS

Of 6,352 patients enrolled, 814 (12.8%) were diagnosed as having AMI. For patients having AMI, there were no statistically significant differences in the proportion of patients treated with thrombolytic therapy between the stat and control groups (15.1% vs. 17.1%, p = 0.45). When only patients with ST segment elevation on their initial electrocardiogram were compared, there were still no significant differences between the groups. Also, there was no difference in the hospital placement of patients in critical care and non- critical care beds. The availability of early markers was associated with more hospital admissions as compared to the control group, as the number of patients discharged from the ED was decreased in the stat versus control groups (28.4% vs. 31.5%, p = 0.023).

CONCLUSIONS

The availability of 0- and 1-h myoglobin and CK-MB results after ED evaluation had no effect on the use of thrombolytic therapy for patients presenting with AMI, and it slightly increased the number of patients admitted to the hospital who had no evidence of acute myocardial necrosis.

Acute results, complications, and effect of lesion characteristics on outcome with the solid-state, pulsed-wave, mid-infrared laser angioplasty system: final multicenter registry report. Holmium:YAG Laser Multicenter Investigators

BACKGROUND AND OBJECTIVE

The solid-state, mid-infrared holmium:YAG laser (2.1 microm wavelength) is a relatively new percutaneous device that has recently been evaluated in a multicenter study. Because of its unique wavelength and photoacoustic effects on atherosclerotic plaques, this laser may be useful in treatment of symptomatic patients with coronary artery disease. This study sought to evaluate the safety and efficacy of mid-infrared laser angioplasty in the treatment of coronary artery lesions.

PATIENTS AND METHODS

Laser angioplasty was performed on 2,038 atherosclerotic lesions in 1,862 consecutive patients with a mean age of 61 +/- 11 years. Clinical indications included unstable angina (69%), stable angina (20%), acute infarction (6%), and positive exercise test (5%). Complex lesion morphology included eccentricity (62%), thrombus (30%), total occlusion (27%), long lesions (14%), and saphenous vein grafts (11%).

RESULTS

This laser catheter alone successfully reduced stenosis (>20%) in 87% of lesions. With adjunct balloon angioplasty, 93% procedural success was achieved. The presence of thrombus within the target lesion was a predictor of procedural success (OR = 2.0 [95% confidence interval 2.0, 4.0], P = .04). Bifurcation lesions (OR = 0.5 [95% confidence interval 0.2, 1.0], P = .05) and severe tortuosity of the treated vessel (OR = 0.4 [95% confidence interval 0.2, 0.9], P = .02) were identified as significant predictors of decreased laser success. Calcium within the lesion was associated with reduced procedural success (OR = 0.57 [95% confidence interval 0.34, 0.97], P = .03), and calcified lesions required significantly more energy pulses than noncalcified lesions (119 +/- 91 pulses vs. 101 +/- 86 pulses, respectively, P = .0002). Complications included in-hospital bypass surgery 2.5%, Q-wave myocardial infarction 1.2%, and death 0.8%. Perforation occurred in 2.2% of patients; major dissection in 5.8% of patients, and spasm in 12% of patients. No predictor of major complications was identified. Six-month angiographic restenosis was documented in 54% of patients, and clinical restenosis occurred in 34% of patients.

CONCLUSION

Mid-infrared laser has a safety profile similar to that of other debulking devices. This laser may be useful in select patients presenting with acute ischemic syndromes associated with intracoronary thrombus; however, like other coronary lasers, it is limited by the need for adjunctive balloon angioplasty and/or stenting to achieve adequate final luminal diameter. No beneficial effects on reducing 6-month restenosis rates were observed.

ST-Segment recovery adds to the assessment of TIMI 2 and 3 flow in predicting infarct wall motion after thrombolytic therapy

BACKGROUND

Early resolution of ST-segment elevation (ST-segment recovery) is associated with an improved outcome after infarction. Whether this relation is present in patients with Thrombolysis In Myocardial Infarction (TIMI) grade 2 or 3 flow (ie, patent) infarct-related arteries is not known.

METHODS AND RESULTS

To examine the associations between time to achieve stable 50% ST-segment recovery assessed by continuous ECG monitoring, infarct artery flow, and infarct zone wall motion (at 48 hours), we studied 134 patients who underwent angiography at 99 (interquartile range 92 to 110) minutes after commencing streptokinase, initiated within 12 hours of onset of symptoms of myocardial infarction. Patients with TIMI 2 or 3 flow who failed to achieve early stable ST-segment recovery (50% ST-segment recovery sustained for > or 4 hours with <100 microV change in the peak lead) by 60 or 90 minutes had a higher fraction of chords in the infarct zone >2 SD below normal wall motion (TIMI 2: 55.5% vs 15.3%, P=0.006; and 56.5% vs 26.8%, P=0.01, respectively; and TIMI 3: 48.8% vs 28.3%, P=0.07; and 51.8% vs 29.9%, P=0.03, respectively). Time to stable ST-segment recovery was a multivariate predictor of infarct zone wall motion (P=0.04) independent of TIMI flow grade and the time from symptom onset to streptokinase therapy.

CONCLUSIONS

In patients with TIMI 2 or 3 flow in infarct-related artery, early stable ST-segment recovery is associated with improved infarct zone wall motion at 48 hours. ST-segment recovery may provide additional information about the degree of myocyte reperfusion achieved in patients with a patent epicardial infarct-related artery after thrombolytic therapy.

Local delivery of heparin post-PTCA: a multicenter randomized pilot study

Bailout stenting for major dissection and threatened closure has high rates of ischemic complications. We performed a randomized trial of local heparin delivery using the infusion sleeve before bailout stenting for suboptimal angioplasty results. In phase I, 20 patients were randomized to local delivery with either 40- or 100-psi infusion pressure. In phase II, 37 patients were randomized to local delivery at 100 psi or standard therapy. Local delivery succeeded in all but one patient; overall there was no significant worsening of intimal dissection. One patient treated with 100-psi drug infusion suffered a perforation after stent placement. There were no significant differences in the composite endpoint of death, MI, CABG, urgent repeat angioplasty, and stent thrombosis at 30 days (21% vs. 0%; P = 0.18). At 6 months, the rates of myocardial infarction in phase II were 27% with local delivery vs. 10% with standard treatment (P = 0.4). Local heparin delivery in dissected vessels may be associated with increased complications and should be approached with caution.

Recurrent ischemia during continuous 12-lead ECG-ischemia monitoring in patients with acute coronary syndromes treated with eptifibatide: relation with death and myocardial infarction. PURSUIT ECG-Ischemia Monitoring Substudy Investigators. Platelet glycoprotein IIb/IIIa in Unstable angina: Receptor Suppression Using Integrilin Therapy

Computer-assisted continuous monitoring of the ST-segment allows detection and quantification of recurrent ischemia in patients with acute coronary syndromes. In a substudy of the PURSUIT (Platelet glycoprotein IIb/IIIa in Unstable angina: Receptor Suppression Using Integrilin Therapy) trial, this technique was used to evaluate the effects of the glycoprotein IIb/IIIa inhibitor eptifibatide on the incidence and severity of recurrent ischemia, and to investigate the relationship between recurrent ischemia and the occurrence of subsequent death or myocardial (re)infarction. A total of 258 patients with unstable angina or evolving myocardial infarction without ST elevation were monitored for 24 hours during infusion with either eptifibatide or placebo with a computer-assisted 12-lead ECG-ischemia monitoring device. Recurrent ischemic episodes were identified by an automated computer algorithm. Two hundred and sixteen patients (84%) had ECG recordings suitable for analysis. Ischemic episodes were detected in 35 (33%) of the 105 eptifibatide patients and in 32 (29%) of the 111 placebo patients (not significant). No difference in ischemic burden was apparent between both treatment groups. Patients who exhibited 2 or more episodes of recurrent ischemia more frequently died or suffered a myocardial infarction, both at 7 and 30 days, as well as through the 6-month follow-up. A greater ischemic burden was significantly related to adverse outcome during the 6-month follow-up period. Real-time computer-assisted continuous multilead ECG-ischemia monitoring may help to identify patients with unstable coronary syndromes at increased risk of adverse outcome and, thus, allow for better prognostic triage and more appropriate selection of therapeutic strategies. Integration of these systems in coronary care units and emergency wards should, therefore, be recommended.

Myocardial ischemia correlates with reduced fibrinolytic activity following peripheral vascular surgery

STUDY OBJECTIVES

To evaluate the relationship between perioperative ischemia and serial concentrations of D-dimer, which is a sensitive and specific marker of fibrinolytic activity. Myocardial ischemia and infarction are well-recognized complications of peripheral vascular surgery. We hypothesized that patients at increased risk of perioperative myocardial ischemia might be identified preoperatively by abnormal hemostatic indices.

DESIGN

Prospective clinical outcomes study.

SETTING

A 1,124-bed tertiary care medical center.

PATIENTS

42 ASA physical status II, III, and IV patients undergoing peripheral vascular surgery.

INTERVENTIONS

Serial D-dimer concentrations were measured preoperatively, and at 24 and 72 hours postoperatively. Continuous 12-lead ST-segment monitoring (Mortara Instrument, Inc., Milwaukee, WI) was performed with the acquisition of a 12-lead ECG every 20 seconds for 72 hours.

MEASUREMENTS AND MAIN RESULTS

D-dimer measurements were performed in duplicate using the Dimer Gold assay (American Diagnostica, Greenwich CT). Ischemic episodes, as defined by continuous 12-lead ST-segment monitoring, occurred in 49% of patients. There were no demographic differences between ischemic and nonischemic groups. Although baseline D-dimer concentrations were not statistically significantly different between groups, patients experiencing perioperative myocardial ischemia generated significantly less D-dimer during the perioperative period (p = 0. 014).

CONCLUSIONS

PATIENTS with an impaired fibrinolytic response, as defined by reduced generation of D-dimer, experienced an increased incidence of perioperative myocardial ischemia.

Prognostic implications of TIMI flow grade in the infarct related artery compared with continuous 12-lead ST-segment resolution analysis. Reexamining the "gold standard" for myocardial reperfusion assessment

OBJECTIVE

To compare the prognostic significance of reperfusion assessment by Thrombolysis in Myocardial Infarction (TIMI) flow grade in the infarct related artery and ST-segment resolution analysis, by correlating with clinical outcomes in patients with acute myocardial infarction (AMI).

BACKGROUND

Angiographic assessment, based on epicardial coronary anatomy, has been considered the "gold standard" for reperfusion. The electrocardiogram (ECG) monitoring provides a noninvasive, real-time physiologic marker of cellular reperfusion and may better predict clinical outcomes.

METHODS

Two hundred fifty-eight AMI patients from the Thrombolytics and Myocardia Infarction phase 7 and Global Utilization of Streptokinase tPA for Occluded coronary arteries phase 1 trials were stratified based on blinded, simultaneous reperfusion assessment on the acute angiogram (divided into TIMI grades 0 & 1, TIMI grade 2 and TIMI grade 3) and ST-segment resolution analysis (divided into: <50% ST-segment elevation resolution or reelevation and > or =50% ST-segment elevation resolution). In-hospital mortality, congestive heart failure (CHF) and combined mortality or CHF were compared to determine the prognostic significance of reperfusion assessment by each modality using chi-square and Fisher's Exact tests for univariable correlation and logistic regression analysis for univariable and multivariable prediction models.

RESULTS

By logistic regression analysis, ST-segment resolution patterns were an independent predictor of the combined outcome of mortality or CHF (p = 0.024), whereas TIMI flow grade was not (p = 0.693). Among the patients determined to have failed reperfusion by TIMI flow grade assessment (TIMI flow grade 0 & 1), the ST-segment resolution of > or =50% identified a subgroup with relatively benign outcomes with the incidence of the combined end point of mortality or CHF 17.2% versus 37.2% in those without ST-segment resolution (p = 0.06).

CONCLUSION

Continuous 12-lead ECG monitoring can be an inexpensive and reliable modality for monitoring nutritive reperfusion status and to obtain prognostic information in patients with AMI.

Multilead ST-segment monitoring in patients with acute coronary syndromes: a consensus statement for healthcare professionals. ST- Segment Monitoring Practice Guideline International Working Group

BACKGROUND

ST-segment monitoring is underused by healthcare professionals for patients with acute coronary syndromes treated in emergency departments and intensive care units.

OBJECTIVE

To provide clinically practical consensus guidelines for optimal ST-segment monitoring.

METHODS

A working group of key nurses and physicians met in Dallas, Tex, in November 1998.

RESULTS

Consensus was reached on who should and should not have ST monitoring, goals and time frames for ST monitoring in various diagnostic categories, what electrocardiographic leads should be monitored, what equipment requirements are needed, what strategies improve accuracy and clinical usefulness of ST monitoring, and what knowledge and skills are required for safe and effective ST monitoring.

CONCLUSIONS

Because changes in the ST segment can shift among various electrocardiographic leads in the same person over time owing to different ischemic mechanisms, 12-lead ST monitoring is recommended. Recommended monitoring times are as follows: myocardial infarction or unstable angina, 24 to 48 hours or until patient is event-free for 12 to 24 hours; chest pain prompting a visit to an emergency department, 8 to 12 hours; catheter-based interventions with less definitive interventional outcomes requiring monitoring in an intensive unit, 6 to 12 hours; and cardiac surgery or noncardiac surgery in patients with coronary disease or risk factors, 24 to 48 hours. An ST measurement point of J + 60 ms makes it unlikely that measurement will coincide with the upslope of the T wave, even in patients with sinus tachycardia. Accurate and consistent lead placement and careful electrode and skin preparation are imperative to improve the clinical usefulness of ST monitoring.

Multilead ST-segment monitoring in patients with acute coronary syndromes: a consensus statement for healthcare professionals. ST- Segment Monitoring Practice Guideline International Working Group

BACKGROUND: ST-segment monitoring is underused by healthcare professionals for patients with acute coronary syndromes treated in emergency departments and intensive care units. OBJECTIVE: To provide clinically practical consensus guidelines for optimal ST-segment monitoring. METHODS: A working group of key nurses and physicians met in Dallas, Tex, in November 1998. RESULTS: Consensus was reached on who should and should not have ST monitoring, goals and time frames for ST monitoring in various diagnostic categories, what electrocardiographic leads should be monitored, what equipment requirements are needed, what strategies improve accuracy and clinical usefulness of ST monitoring, and what knowledge and skills are required for safe and effective ST monitoring. CONCLUSIONS: Because changes in the ST segment can shift among various electrocardiographic leads in the same person over time owing to different ischemic mechanisms, 12-lead ST monitoring is recommended. Recommended monitoring times are as follows: myocardial infarction or unstable angina, 24 to 48 hours or until patient is event-free for 12 to 24 hours; chest pain prompting a visit to an emergency department, 8 to 12 hours; catheter-based interventions with less definitive interventional outcomes requiring monitoring in an intensive unit, 6 to 12 hours; and cardiac surgery or noncardiac surgery in patients with coronary disease or risk factors, 24 to 48 hours. An ST measurement point of J + 60 ms makes it unlikely that measurement will coincide with the upslope of the T wave, even in patients with sinus tachycardia. Accurate and consistent lead placement and careful electrode and skin preparation are imperative to improve the clinical usefulness of ST monitoring.

Comparison of slow oscillating versus fast balloon inflation strategies for coronary angioplasty

Previous studies suggest that slow and/or oscillating balloon inflation during coronary angioplasty may decrease the incidence of coronary dissection and improve clinical outcomes. To compare the effect of slow oscillating versus conventional fast inflation techniques on the incidence of severe coronary dissection during angioplasty, 622 patients were randomized to slow oscillating inflation versus fast inflation. Angiographic outcomes of the procedures and in-hospital clinical events were recorded. The primary end point of severe (type C, D, E, F) dissection occurred in 7.7% of patients undergoing slow oscillation and 6.6% of patients undergoing fast inflation (p = 0.87). Major complications (death, urgent coronary artery bypass graft surgery, stroke, abrupt closure, or Q-wave myocardial infarction) occurred in 4.7% of patients undergoing slow oscillation and 3.5% of patients undergoing fast inflation (p = 0.45). The 2 inflation strategies did not differ in the pressure at which the balloon achieved full expansion, angiographic success rate, residual stenosis, and incidence of all minor and/or major complications. We conclude that there is no benefit of slow oscillating inflation over routine fast inflation in angioplasty. Slow oscillating inflation did not dilate lesions at lower pressures, decrease the incidence of dissection or severe dissection, or reduce the incidence of adverse clinical outcomes.

QT prolongation and dispersion in myocardial ischemia and infarction

The ability of QT interval dispersion to predict the occurrence of ventricular fibrillation (VF) after acute myocardial infarction treated with thrombolytic therapy is controversial. Continuous 12-lead electrocardiographic (ECG) monitoring for 48 hours or longer provides an opportunity to detect transient changes of QT dispersion and correlate such changes with the clinical outcome. In 543 consecutive patients enrolled in the TAMI-9 and GUSTO I studies, serial changes of the QT dispersion were analyzed in an attempt to predict the occurrence of VF with a system that monitored continuously the 12-lead ECG and stored it at least every 20 minutes. Measurements of QT dispersion were made at a median time of 2.37 hours after the onset of chest pain and at 24- and 48-hour intervals. A total of 43 patients experienced VF during the acute phase of myocardial infarction; of these patients, 33 (77%) had anterior infarcts. However, despite the higher preponderance of anterior myocardial infarcts in the VF group, patients with anterior infarcts did not have longer QT dispersion than those with other infarct locations. Similarly, no significant differences in the QT dispersion were observed at any time between the group with VF and that without. Women had increased QT dispersion in the initial and 24-hour ECG as compared with men (P = .005). However, this normalized at the 48-hour measurements. Despite this difference, there was no higher incidence of VF in female patients. In conclusion, the data suggest that QT dispersion alone is not sufficient to explain the occurrence of VF in the acute phase of myocardial infarction after thrombolytic therapy.

Device implementation, validation, and application assessment of two continuous 12-lead ECG monitors during percutaneous transluminal coronary angioplasty: description of the validation method and implications for clinical trials

Comparability of clinical and research data sets may be undermined if the instruments used to acquire them vary. Even when standard 12-lead electrocardiographic formats are used for monitoring, proprietary signal processing techniques and sampling intervals may differ among devices. In order to directly compare the two commercially available standard 12-lead devices with monitoring capabilities, bifurcated wires from a single standard lead set were attached to each device in elective angioplasty patients. Neither device was used as a standard; rather, a method was designed to analyze the output from each device independently, and then, if results differed, data from both monitors were reviewed by consensus to determine the source of the differences. Analysis endpoints for each study included study quality, baseline ST-segment levels, the presence of ischemia, number of ischemic episodes, peak lead location, and peak lead amplitude. Sources of differences in these endpoints visible to consensus review included variations between devices in baseline stability, noise/artifact levels, stability of the QRS complex onset, and temporal sampling intervals.

Incidence and long-term significance of transient ST segment deviation in hemodialysis patients

Coronary artery disease is a frequent complication of end-stage renal disease (ESRD). ST segment depression on ambulatory electrocardiography without patient awareness is a marker of what has been termed "silent ischemia". It has been suggested that in patients with coronary artery disease these transient ST segment depressions are associated with increased cardiovascular mortality. Up to 30% of patients with ESRD may display transient ST segment depression, however the significance of this finding in these group of patients who frequently have associated LV hypertrophy, and rapid electrolyte changes has not been clear. We therefore set out to determine the incidence of transient ST segment depression during ambulatory Holter monitoring in 70 consecutively studied hemodialysis patients. Sixty-seven patients wore the monitor for at least 12 hours and 16 patients (23%) demonstrated at least one minute of 1 mm ST segment depression. The presence of clinically apparent coronary artery disease, diabetes, left ventricular hypertrophy, sex or race were not significantly associated with the probability of demonstrating transient ST segment depression. The survival of patients with or without transient ST segment depression was the same at 2 years with 70% of patients remaining free of death, nonfatal myocardial infarction, or coronary bypass grafting. We conclude that patients with ESRD frequently demonstrate transient ST segment depression, however, the presence of these findings on ambulatory Holter monitoring does not appear to be associated with increased long-term mortality.

Prognostic significance of ST segment shift early after resolution of ST elevation in patients with myocardial infarction treated with thrombolytic therapy: the GUSTO-I ST Segment Monitoring Substudy

OBJECTIVES

We sought to study the relation between recurrent ST segment shift within 6 to 24 h of initial resolution of ST elevation after thrombolytic therapy and 30-day and 1-year mortality.

BACKGROUND

Rapid and stable resolution of ST segment elevation in relation to thrombolytic therapy in patients with an acute myocardial infarction is an indicator of culprit artery patency. Whether recurrence of ST segment shift during continuous ST monitoring after initial resolution is related to poor prognosis has not been studied.

METHODS

ST segment monitoring was performed within 30 min after thrombolytic therapy for acute myocardial infarction. The predictive value of a new ST segment shift (assessed as > or = 0.1-mV deviation from the baseline) 6 to 24 h after thrombolytic therapy was studied with respect to 30-day and 1-year mortality.

RESULTS

Of 734 patients, 243 had a new ST segment shift (33%). The 30-day mortality rate in patients with an ST shift (7.8%) was significantly higher than that in patients without an ST shift (2.25%, p = 0.001), as was the 1-year mortality rate (10.3% vs. 5.7%, respectively, p = 0.025). Multivariable analysis revealed an independent predictive value of ST shift with respect to 30-day mortality (p = 0.008), even after consideration of multiple clinical risk factors in the overall Global Utilization of Streptokinase and TPA for Occluded Coronary Arteries (GUSTO)-I mortality model (p = 0.0001). Moreover, the duration of the ST shift bore a direct relation with 1-year mortality (p = 0.008).

CONCLUSIONS

Detection of ST segment shift early after thrombolytic therapy for acute myocardial infarction is a simple, noninvasive means of identifying patients at high risk and is superior to other commonly assessed clinical risk factors. Thus, patients with a new ST shift after the first 6 h, but within 24 h, represent a high risk group that may benefit from more aggressive intervention, whereas patients without evidence of an ST shift represent a low risk subgroup.

Comparative prognostic significance of simultaneous versus independent resolution of ST segment depression relative to ST segment elevation during acute myocardial infarction

OBJECTIVES

We sought to determine the prognostic significance of simultaneous versus independent resolution of ST segment depression that occurs concomitant with ST segment elevation during acute myocardial infarction (AMI).

BACKGROUND

ST segment depression in leads other than those showing ST segment elevation during AMI is a common phenomenon. Whether this indicates adverse outcomes remains controversial. We hypothesized that the timing of ST segment depression resolution relative to ST segment elevation resolution might differentiate between a high risk group and a low risk group of patients.

METHODS

Continuous 12-lead ST segment monitoring was performed after thrombolytic therapy for AMI in 413 patients, 261 of whom met technical criteria for analysis. Blinded analysis of ST segment depression resolution patterns was used to group patients as follows: 1) no ST segment depression at any time (control group); 2) ST segment depression resolving simultaneously with ST segment elevation (simultaneous group); and 3) ST segment depression persisting after ST segment elevation resolution (independent group). These patterns were correlated with the outcomes-recurrent angina, reinfarction, heart failure and death-using chi-square analysis and the Fisher exact test for categoric variables and the Wilcoxon rank-sum test for continuous variables.

RESULTS

The incidence of recurrent angina, reinfarction and heart failure was similar among the three groups. In-hospital mortality, however, was significantly higher in the independent group (13%) than either the simultaneous group (1%, p < 0.001) or the control group (0%, p = 0.002).

CONCLUSIONS

Continuous analysis of ST segment resolution identifies, among patients with AMI with concomitantly occurring ST segment elevation and depression, a subgroup with increased in-hospital mortality. The pathogenic mechanism of increased mortality is not currently known.

Electrocardiographic differentiation of the ST-segment depression of acute myocardial injury due to the left circumflex artery occlusion from that of myocardial ischemia of nonocclusive etiologies

Lead distributions of peak ST-segment depression were compared between patients undergoing left circumflex artery percutaneous transluminal coronary angioplasty and exercise tolerance test. Localization of peak ST-segment depression to leads V2 or V3 was 96% specific and 70% sensitive for differentiating ischemia due to occlusion of left circumflex artery occlusion from nonocclusive ischemia.

Combined accelerated tissue-plasminogen activator and platelet glycoprotein IIb/IIIa integrin receptor blockade with Integrilin in acute myocardial infarction. Results of a randomized, placebo-controlled, dose-ranging trial. IMPACT-AMI Investigators

BACKGROUND

Platelet activation and aggregation may be key components of thrombolytic failure to restore and maintain perfusion in acute myocardial infarction. We performed a placebo-controlled, dose-ranging trial of Integrilin, a potent inhibitor of platelet aggregation, with heparin, aspirin, and accelerated alteplase.

METHODS AND RESULTS

We assigned 132 patients in a 2:1 ratio to receive a bolus and continuous infusion of one of six Integrilin doses or placebo. Another 48 patients were randomized in a 3:1, double-blind fashion to receive the highest Integrilin dose from the first phase or placebo. All patients received accelerated alteplase, aspirin, and intravenous heparin infusion; all but two groups also received an intravenous heparin bolus. The highest Integrilin dose group from the nonrandomized phase and the randomized patients were pooled for analysis and compared with placebo-treated patients. The primary end point was Thrombolysis in Myocardial Infarction (TIMI) grade 3 flow at 90-minute angiography. Secondary end points were time to ST-segment recovery, an in-hospital composite (death, reinfarction, stroke, revascularization procedures, new heart failure, or pulmonary edema), and bleeding variables. The highest Integrilin dose groups had more complete reperfusion (TIMI grade 3 flow, 66% versus 39% for placebo-treated patients; P = .006) and a shorter median time to ST-segment recovery (65 versus 116 minutes for placebo; P = .05). The groups had similar rates of the composite end point (43% versus 42% for placebo-treated patients) and severe bleeding (4% versus 5%, respectively).

CONCLUSIONS

The incidence and speed of reperfusion can be enhanced when a potent inhibitor of the glycoprotein IIb/IIIa integrin receptor, such as Integrilin, is combined with accelerated alteplase, aspirin, and intravenous heparin.

Incidence and clinical relevance of the occurrence of bundle-branch block in patients treated with thrombolytic therapy

BACKGROUND

Whether thrombolytic therapy alters the incidence and clinical outcome of bundle-branch block is unclear.

METHODS AND RESULTS

We examined the occurrence of new-onset bundle-branch block, both transient and persistent, in 681 patients with acute myocardial infarction enrolled in the Thrombolysis and Angioplasty in Myocardial Infarction 9 and Global Utilization of Streptokinase and t-PA for Occluded Arteries 1 protocols. Each patient underwent continuous 12-lead ECG monitoring for 36 to 72 hours with the Mortara ST monitoring system. Bundle-branch block was characterized as right, left, alternating, transient, or persistent. The overall incidence of bundle-branch block was 23.6% (n = 161), with transient block in 18.4% (n = 125) and persistent block in 5.3% (n = 36). Right bundle-branch block was found in 13% (n = 89) of the population; left bundle-branch block was found in 7% (n = 48). Alternating bundle-branch block was seen in 3.5% (n = 24) of patients. Left anterior descending artery infarcts accounted for most bundles (54%, n = 79). Patients with bundle-branch block had lower ejection fractions, higher peak creatine phosphokinase levels (P < .0001), and more diseased vessels (P < .019). Mortality rates in patients with and without bundle-branch block were 8.7% and 3.5%, respectively (P < .007). A higher mortality rate was observed in the presence of persistent (19.4%) versus transient (5.6%) or no (3.5%) bundle-branch block (P < .001).

CONCLUSIONS

Thrombolytic therapy reduces the overall mortality rate associated with persistent bundle-branch block. However, persistent bundle-branch block remains predictive of a higher mortality rate than either transient or no bundle-branch block. Continuous 12-lead ECG monitoring provides an accurate characterization of the incidence and type of conduction disturbances after acute myocardial infarction.

Performance of an automated real-time ST-segment analysis program to detect coronary occlusion and reperfusion

Continuously updated ST-segment recovery analysis has been shown to accurately predict infarct-related artery patency. Salient principles were converted into algorithms and incorporated into a portable ST monitor for optimal application. This study tested the automated program's ability to detect occlusion and reperfusion during balloon angioplasty. ST-segment recordings during 78 balloon occlusions in 31 patients were analyzed. The program requires at least one electrocardiogram with ST elevation of 200 microV or greater in the recording, caused by the current occlusion or by a previous occlusion, before it will yield a patency prediction. All 35 inflations causing peak ST elevation of 200 microV or more were indeed detected. All five inflations causing less than 200 microV ST elevation preceded by an inflation causing 200 microV or higher ST elevation were also detected. Occlusion was detected a median of 40 seconds after inflation, and reperfusion a median of 17 seconds after deflation. Peak ST elevation greater than 200 microV occurred in 19 of 26 left anterior descending artery inflations (73%), 1 of 22 left circumflex artery LCX inflations (5%), and 15 of 30 right coronary artery inflations (50%). Five different leads identified peak ST elevation through 12-lead surveillance. In this model of coronary occlusion during angioplasty balloon inflation, the automated patency assessment program appears to detect coronary angioplasty balloon occlusion and reperfusion within seconds in all occlusions causing a peak ST elevation of 200 microV or greater. Testing this automated patency assessment program as a noninvasive triage tool in myocardial infarction patients seems warranted.

A randomized factorial trial of reperfusion strategies and aspirin dosing in acute myocardial infarction. The DUCCS-II Investigators

The focus of new research efforts to improve the morbidity and mortality associated with acute myocardial infarction (AMI) has turned to adjuvant agents that show promise of improving outcomes following coronary thrombolysis. We enrolled 162 patients with AMI in a randomized trial comparing front-loaded tissue-plasminogen activator (t-PA) plus weight-adjusted heparin with anisoylated plasminogen streptokinase activator complex (APSAC) without heparin as well as standard-dose (325 mg) and low-dose (81 mg) aspirin. The primary end point was an in-hospital morbidity profile; secondary end points were clinical and angiographic potency and hemorrhagic events. Selected sites performed an electrocardiographic substudy to determine the time to 50% ST-segment recovery and the time to steady state. Although the trial was terminated when the Global Utilization of Streptokinase and t-PA for Occluded Coronary Arteries-I trial showed that t-PA had a significant mortality advantage over streptokinase, important trends were evident. Patients given t-PA and heparin were better anticoagulated (p = 0.001), yet AP-SAC-treated patients had more bleeding complications. The primary end point favored t-PA (25.4% vs 31.3%), and the secondary end points were similar in both groups. In the electrocardiographic substudy, the t-PA group achieved both 50% ST-segment recovery and steady-state recovery sooner than the APSAC group. Patients taking low-dose aspirin had lower in-hospital mortality and less recurrent ischemia but more strokes than the standard-dose aspirin group. Thus, this trial demonstrated trends favoring front-loaded t-PA with weight-adjusted heparin over APSAC without heparin in the treatment of AMI. The use of low-dose aspirin did not appear to impose a loss of protection from adverse events, nor did standard-dose aspirin increase serious bleeding.

Periprocedural myocardial ischemia in patients with severe symptomatic coronary artery disease undergoing endoscopy: prevalence and risk factors

PURPOSE

To determine the prevalence of and risk factors for periprocedural myocardial ischemia associated with gastrointestinal endoscopy in patients with severe symptomatic coronary artery disease.

PATIENTS AND METHODS

In this prospective observational study, myocardial ischemia (ST segment change > 100 microV in any 2 leads or > 200 microV in any 1 lead, lasting > 60 seconds) was assessed using a continuous 12-lead digital electrocardiographic monitor before, during, and after gastrointestinal endoscopy.

RESULTS

Between June 1992 and May 1993, 1,084 esophagogastroduodenoscopies and 588 colonoscopies were performed during 1,438 consecutive endoscopies on patients admitted to a university hospital. Seventy (18%) of 252 patients with prior angiography had significant coronary artery disease. Fifty-two (74%) were successfully enrolled, and satisfactory electrocardiographic recordings were obtained from 49 (median age 65 years, interquartile range 58 to 74). Thirty-six were men, 12 had myocardial infarctions within the 6 weeks (median 12.5 days, interquartile range 8 to 18), and 25 had unstable angina. The coronary artery disease involved 1 vessel in 14 subjects, 2 vessels in 21, and 3 vessels in 14. Nineteen episodes of ischemia (4 pre-, 6 intra-, 9 postprocedure) were detected in 8 patients (16%; 95% confidence interval, 6% to 26%) during the recording period (median duration 322 min, interquartile range 227 to 429). One patient became symptomatic with a myocardial infarction. Multivariable logistic regression showed that women experienced more periprocedural ischemia compared to men (31% versus 11%; P = 0.058).

CONCLUSIONS

Myocardial ischemia occurs during the periprocedural period in 16% of hospitalized patients with severe coronary artery disease undergoing gastrointestinal endoscopy. Endoscopy is safe in hemodynamically stable patients with recent myocardial infarction and/or unstable angina. Women appear to be at greater risk for periprocedural ischemia associated with endoscopy.

Noninvasive assessment of speed and stability of infarct-related artery reperfusion: results of the GUSTO ST segment monitoring study. Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries

OBJECTIVES

The ST segment monitoring substudy of the Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries (GUSTO-I) trial compared the speed and stability of ST segment recovery among four thrombolytic strategies for acute myocardial infarction.

BACKGROUND

Rapid resolution of ST segment elevation has been suggested as a noninvasive marker of infarct-related artery patency. We expected that patients treated with accelerated recombinant tissue-type plasminogen activator (rt-PA) would show a quicker recovery than that of other patients but that those treated with streptokinase would show greater stability of recovery.

METHODS

ST segment monitoring was initiated in 1,067 patients within 30 min of the start of thrombolysis and continued for > 18 h with the use of a three-channel continuous vectorcardiographic monitor, a 12-lead continuous electrocardiographic (ECG) monitor or a three-channel (V2, V5, aVF) Holter ambulatory ECG monitor.

RESULTS

Time to 50% recovery could be assessed in 618 patients and was similar in the four treatment groups: median 45 min with streptokinase/subcutaneous heparin, 45 min with streptokinse/intravenous heparin, 42 min with accelerated rt-PA and 47 min with combination therapy (p = 0.7). No significant difference among the thrombolytic regimens was shown with the three monitors used. Time to initiation of ST segment analysis was directly related to time to 50% recovery (p = 0.0001) and was its best predictor in a multiple regression model. ST segment elevation recurred equally in each treatment group (approximately 36%, p = 0.9) but was significantly more common in patients with a patent infarct-related artery (p = 0.033) or a low ejection fraction (p = 0.001).

CONCLUSIONS

The greater 90-min patency seen with accelerated rt-PA in the angiographic substudy did not correlate with a shorter time to 50% ST segment recovery, possibly because of technical limitations and study design. The similar rates of recurrent ischemia (as assessed by ST elevation) among the regimens support the similar infarction and reocclusion rates seen in the main trial and angiographic substudy.

Rebound increase in thrombin generation and activity after cessation of intravenous heparin in patients with acute coronary syndromes

BACKGROUND

The abrupt cessation of heparin and other thrombin inhibitors when used to treat acute coronary syndromes has been accompanied by a clustering of thrombotic events. It is unknown whether these events are the result of inadequate antithrombin therapy or whether they represent a rebound increase in thrombin activity. This study was designed to determine whether there is a true rebound, as defined by an increase followed by a subsequent decrease, in thrombin activity after discontinuation of intravenous heparin therapy.

METHODS AND RESULTS

Thirty-five patients with recent acute myocardial infarction or unstable angina who had received at least 48 hours of intravenous heparin were studied. Patients underwent ST-segment monitoring, and blood samples for determination of thrombin generation and activity were drawn at 0, 3, 6, 10, and 24 hours after heparin discontinuation. Median aPTT was 65 seconds before heparin discontinuation. Median fibrinopeptide A increased from 9.5 to 16.9 ng/mL at 3 hours (P < .0004) and returned to 10.5 by 24 hours. Prothrombin fragment 1.2 likewise transiently increased, from 0.34 to 0.51 nmol/L at 6 hours (P < .0002). Modified antithrombin III decreased over time (P < .002), and activated protein C increased from 2.3 to 4.5 ng/mL at 3 hours (P < .001). Although there were no clinical thrombotic events in the first 24 hours, 4 patients had evidence of ischemia by ST-segment monitoring at a median of 12 hours after heparin discontinuation. The degree of increase in fibrinopeptide A and prothrombin fragment 1.2 was not found to be associated with baseline diagnosis, duration of heparin therapy, baseline level of antithrombin III, or activated protein C.

CONCLUSIONS

This study demonstrates a transient rebound increase in thrombin activity as well as in activated protein C upon abrupt discontinuation of intravenous heparin. Clinicians should be vigilant for associated thrombotic events. Further investigation of the significance, mechanism, and possible prevention of this rebound phenomenon is needed.

Simultaneous ST-segment measurements using standard and monitoring-compatible torso limb lead placements at rest and during coronary occlusion

Electrocardiographic recordings used to assess ST-segment deviation are performed using both standard and torso limb lead positions, where bony prominences give more artifact-free signal. Whereas significant QRS artifact can be introduced by such changes in lead location, the impact on ST-segment measurements has never been assessed. Digital electrocardiographic recordings were performed in 29 patients throughout elective angioplasty balloon inflation in the left anterior descending (n = 12), right coronary (n = 14), and circumflex (n = 3) arteries. In all cases, unipolar leads V1, V4, and V6 were affixed to the torso lead positions, allowing reconstruction of simultaneously acquired standard and modified 9-lead electrocardiograms (ECGs). ST levels in the 26 patients who had ST deviation during angioplasty were compared at both baseline and peak ischemia of up to 1,046 microV in the anterior, and 551 microV in the inferior leads. Differences in recorded ST levels for modified versus standard lead locations were all < 100 microV, even at peak ischemia. Although ST-segment elevation in the inferior leads appeared to show slightly more pronounced differences between lead sets than did anterior elevation, all differences were < 100 microV. Thus, measurement of ST-segment levels appears unlikely to be importantly affected by the intermixture of ECGs recorded with standard lead positions and ECGs recorded with monitoring-compatible lead positions on the torso. Recalibration of ST-segment measurements may be necessary for meticulous quantification of ischemia, infarct size, or other measurements that might be affected by variations < 100 microV.

The impact of autoperfusion on quantitative electrocardiographic parameters of ischemia severity, extent, and "burden" during salvage of elective coronary angioplasty

Long angioplasty inflations have been reported using an autoperfusion system that delivers oxygenated blood distal to the balloon segment. The safety and efficacy of this system has been demonstrated in anatomically selected patients. The clinical use, however, is frequently to stabilize intimal dissection in unselected patients. We reviewed 12-lead continuous electrocardiographic (ECG) recordings in 40 patients in whom prolonged salvage with autoperfusion was attempted. Sub-optimal results were stabilized in 36 of 40, while 4 patients had urgent bypass. The presence of ischemia, as > or = 100 uV ST elevation over the 12 lead ECG, and the total ST deviation over all leads over the entire inflation period (total ischemic "burden") were compared within each patient between the longest standard balloon and autoperfusion inflations. Median duration of inflation was 3.03 min. with balloon vs. 15.6 min. with autoperfusion (p < 0.00002). Of the 40 patients, 35 (87%) had ECG ischemia with balloon vs. 18 (45%) with autoperfusion (p < .00002). Median severity of peak ST deviation was 321 uV with balloon vs. 132 uV with autoperfusion (p = 0.0001). Median extent of ST elevation was 3 leads with balloon vs. 0 leads with autoperfusion (p = 0.0001). Median total ischemic burden was similar with balloon (1173 uVmin) and autoperfusion (1083 uVmin, NS) despite the fivefold longer inflation duration with autoperfusion. Thus, in patients selected by clinical necessity rather than optimal anatomy, severity and extent of ST elevation were significantly reduced, although not entirely eliminated, by autoperfusion.

Randomized evaluation of coronary angioplasty for early TIMI 2 flow after thrombolytic therapy for the treatment of acute myocardial infarction: a new look at an old study. The Thrombolysis and Angioplasty in Myocardial Infarction (TAMI) Study Group

BACKGROUND

Patients who have suffered acute myocardial infarction (AMI) and have been treated with intravenous thrombolytic agents resulting in early 'patent' [Thrombolysis in Myocardial Infarction (TIMI) 2-3 flow grade] arteries have been shown not to benefit from early percutaneous transluminal coronary angioplasty (PTCA). Recent data, however, suggest that the clinical outcome of patients with early TIMI 2 flow is decidedly inferior to that of patients with TIMI 3 flow, raising the question whether early PTCA might be beneficial for patients with TIMI 2 flow. The clinical utility of PTCA for this particular subset of patients has never been assessed.

METHODS

We analyzed left ventricular ejection fraction (LVEF) recovery by contrast ventriculography and clinical outcome in Thrombolysis and Angioplasty in Myocardial Infarction Phase I (TAMI-I) study patients with initial TIMI 2 flow grade, determined by blinded core laboratory analysis.

RESULTS

No differences were observed between baseline demographic data for the 49 patients randomly assigned to undergo early PTCA compared with that from the 59 patients randomly assigned to receive early medical therapy. Patients were 56 +/- 11 years of age (mean +/- SD), 80% were men, the time from onset of chest pain to catheterization was 268 +/- 71 min, 42% had anterior AMI, and 42% had multivessel disease. Ninety minute baseline LVEF to prehospital discharge LVEF was minimally better in the group randomly assigned to undergo PTCA (51 +/- 12 to 52 +/- 11% versus 55 +/- 10 to 53 +/- 12%, P = 0.06). This contrasted with findings in patients with TIMI 3 flow grade at baseline, which showed a relative benefit for patients randomly assigned to receive early medical therapy (54 +/- 10 to 54 +/- 8% for PTCA, versus 55 +/- 10 to 58 +/- 8% for medical therapy, P = 0.01). Among patients with TIMI 2 flow grade there were no differences in in-hospital death or congestive heart failure (6.1 versus 1.7%, P = 0.25 and 18.4 versus 23.7%, P = 0.50, PTCA versus medical therapy, respectively).

CONCLUSION

We conclude that (1) PTCA of infarct-related arteries with TIMI 2 flow grade may modestly improve recovery of left ventricular function, and (2) widespread application of PTCA in this setting should be deferred, pending demonstration that this benefit outweighs the risks of PTCA.