Residual flow to the infarct zone as a determinant of infarct size after direct angioplasty

Early versus late delayed percutaneous coronary intervention in elderly patients with ST-segment elevation myocardial infarction

BACKGROUND AND OBJECTIVE

There are a substantial proportion of elderly patients with ST-segment elevation myocardial infarction (STEMI) miss the optimal time window (12 h from symptom onset) of primary percutaneous coronary intervention (PCI). For these patients, the ideal timing of delayed PCI remains undetermined. Therefore, this study compared the clinical outcomes of early versus late delayed PCI in elderly patients with STEMI.

METHODS

From January 2014 to September 2019, 512 patients aged ≥ 65 years with STEMI who underwent delayed PCI after 12 h from symptom onset were included and then categorized into the early PCI group (12-48 h, n = 111) and late PCI group (48 h-28 days, n = 401) according to the timing of delayed PCI. Propensity score matching (PSM) was conducted to adjust the confounding factors between groups. The primary endpoint was major adverse cardiac and cerebrovascular events (MACCE), a composite of all-cause death, cardiac death, recurrent myocardial infarction (MI), stroke, and ischemia-driven revascularization.

RESULTS

During a mean follow-up of 77 months, 163 (31.8%) patients developed MACCE and 93 (18.2%) died. Early or late delayed PCI did not make a significant difference in clinical outcomes of MACCE (Before PSM: HR 0.773, 95% CI 0.520-1.149, P = 0.203; After PSM: HR 0.869, 95% CI 0.498-1.517, P = 0.622), all-cause death, cardiac death, recurrent MI, stroke, and ischemia-driven revascularization in both overall patients and the PSM cohorts.

CONCLUSION

Early delayed PCI (12-48 h from symptom onset), for elderly patients with STEMI who present > 12 h after symptom onset is not associated with better long-term clinical outcomes compared with late delayed PCI (48 h-28 days).

Coronary Intervention in ST-Segment Elevation Myocardial Infarction Patients With Symptom Onset >12 Hours: Data from China Acute Myocardial Infarction Registry

To determine whether late percutaneous coronary intervention (PCI) of an infarct-related artery >12 h after ST-segment elevation myocardial infarction onset is beneficial, patients were included from the prospective, nationwide, multicenter China Acute Myocardial Infarction registry. The number of patients who underwent PCI or received drug therapy alone was 4791 and 1149, respectively. Hazard ratio (HR) and associated 95% confidence interval (CI) were calculated. Compared with drug therapy, PCI was associated with lower incidences of 2-year major adverse cardiac and cerebrovascular events (MACCE; 6.43 vs 20.19%; HR, .27; 95% CI, .23-.32; P < .001), all-cause death (4.13 vs 15.74%; HR, .24; 95% CI, .20-.30; P < .001), myocardial infarction (1.73 vs 3.31%; HR, .49; 95% CI, .33-.72; P = .0003), stroke (1.02 vs 2.00%; HR, .47; 95% CI, .28-.77; P = .0026), and revascularization (10.96 vs 27.56%; HR, .32; 95% CI, .26-.39; P < .001). Subgroup analysis consistently indicated that PCI was superior to drug therapy. Moreover, the left ventricular ejection fraction in the PCI group was increased after 2-year follow-up, whereas there was no significant increase in the drug therapy group. In conclusion, late PCI is common in Chinese clinical practice, and it is associated with significant improvements in cardiac function and survival compared with drug therapy alone.

Mechanical complications in ST-elevation myocardial infarction: The impact of pre-hospital delay

AIMS

Mechanical complications (MC) (i.e., free wall rupture (FWR), papillary muscle rupture (PMR) and ventricular septal rupture (VSR)) are rare complications of ST- elevation acute myocardial infarction (STEMI). Incidence of MC according to pre-hospital delay remains unknown. We aimed to determine the rates of MC according to pre-hospital delay.

METHODS

Analysis was conducted on the MODIF registry data. Patients were allocated to four groups according to pre-hospital delay: 0 to 12 h, 12 to 24 h, 24 to 36 h and 36 to 48 h.

RESULTS

6185 patients with complete data were analyzed. Mean age was 64.1 years old and 75.7% of patients were males. Eighty-three patients (1.34%) presented with MC: 44 (0.71%) experienced a FWR, 17 (0.27%) a PMR, and 22 (0.36%) a VSR. Global rates of MC were 0.82%, 1.43%, 1.24% and 5.07% in the four groups of pre-hospital delays - 0 to 12 h, 12 to 24 h, 24 to 36 h and 36 to 48 h - respectively (p < 0.001). In-hospital mortality rates were high: 44.2%, 47.1% and 54.6% for FWR, PMR and VSR, respectively. In multivariate analysis, factors independently related to the occurrence of MC were older age, female sex, simultaneous COVID-19 infection, absence of dyslipidemia, initial TIMI flow 0 or 1 in the culprit artery, 36 to 48 h-pre-hospital delay and absence of revascularization by percutaneous coronary intervention (PCI) with stent implantation.

CONCLUSION

The probability of MC in STEMI increases with pre-hospital delay. Mechanical complications of STEMI remain associated with a very poor prognosis.

Percutaneous Myocardial Revascularization in Late-Presenting Patients With STEMI

BACKGROUND

The optimal management of patients with ST-segment elevation myocardial infarction (STEMI) presenting late->12 hours following symptom onset-is still under debate.

OBJECTIVES

The purpose of this study was to describe characteristics, temporal trends, and impact of revascularization in a large population of latecomer STEMI patients.

METHODS

The authors analyzed the data of 3 nationwide observational studies from the FAST-MI (French Registry of Acute ST-elevation and non-ST-elevation Myocardial Infarction) program, conducted over a 1-month period in 2005, 2010, and 2015. Patients presenting between 12 and 48 hours after symptom onset were classified as latecomers.

RESULTS

A total of 6,273 STEMI patients were included in the 3 cohorts, 1,169 (18.6%) of whom were latecomers. After exclusion of patients treated with fibrinolysis and patients deceased within 2 days after admission, 1,077 patients were analyzed, of whom 729 (67.7%) were revascularized within 48 hours after hospital admission. At 30-day follow-up, all-cause death rate was significantly lower among revascularized latecomers (2.1% vs 7.2%; P < 0.001). After a median follow-up of 58 months, the rate of all-cause death was 30.4 (95% CI: 25.7-35.9) per 1,000 patient-years in the revascularized latecomers group vs 78.7 (95% CI: 67.2-92.3) per 1,000 patient-years in the nonrevascularized latecomers group (P < 0.001). In multivariate analysis, revascularization of latecomer STEMI patients was independently associated with a significant reduction of mortality occurrence during follow-up (HR: 0.65 [95% CI: 0.50-0.84]; P = 0.001).

CONCLUSIONS

Coronary revascularization of latecomer STEMI patients is associated with better short and long-term clinical outcomes.

Adenosine-Induced Coronary Steal Is Observed in Patients Presenting With ST-Segment-Elevation Myocardial Infarction

Background Adenosine is used to treat no-reflow in the infarct-related artery (IRA) during ST-segment-elevation myocardial infarction intervention. However, the physiological effect of adenosine in the IRA is variable. Coronary steal-a reduction of blood flow to the distal coronary bed-can occur in response to adenosine and this is facilitated by collaterals. We investigated the effects of adenosine on coronary flow reserve (CFR) in patients presenting with ST-segment-elevation myocardial infarction to better understand the physiological mechanism underpinning the variable response to adenosine. Methods and Results Pressure-wire assessment of the IRA after percutaneous coronary intervention was performed in 93 patients presenting with ST-segment-elevation myocardial infarction to calculate index of microvascular resistance, CFR, and collateral flow index by pressure. Modified collateral Rentrop grade to the IRA was recorded, as was microvascular obstruction by cardiac magnetic resonance imaging. Coronary steal (CFR <0.9), no change in flow (CFR=0.9-1.1), and hyperemic flow (CFR >1.1) after adenosine occurred in 19 (20%), 15 (16%), and 59 (63%) patients, respectively. Patients with coronary steal had higher modified Rentrop score to the IRA (1 [0, 1.75] versus 0 [0, 1], P<0.001) and a higher collateral flow index by pressure (0.25±0.10 versus 0.15±0.10, P=0.004) than the hyperemic group. The coronary steal group also had significantly higher index of microvascular resistance (61.68 [28.13, 87.04] versus 23.93 [14.67, 37.00], P=0.006) and had more disease (stenosis >50%) in the donor arteries (52.63% versus 22.03%, P=0.02) than the hyperemic group. Conclusions Adenosine-induced coronary steal may be responsible for a reduction in coronary flow reserve in a proportion of patients presenting with ST-segment-elevation myocardial infarction. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT03145194. URL: https://www.isrctn.com; Unique identifier: ISRCTN3176727.

Cardioprotection by an anti-MASP-2 antibody in a murine model of myocardial infarction

Background

Myocardial ischaemia-reperfusion injury is a major cause of mortality and morbidity in the developed world. Many approaches have been investigated to counteract the pathological consequences associated with acute myocardial infarction (AMI) and cardiac remodelling. It is accepted that inflammation, and therefore activation of the complement pathway, is a crucial step in the pathogenesis of this injury, and many attempts have been made to ameliorate the infarction and consequent dysfunction using anticomplement therapy, with mixed success. Recently, the lectin complement activation pathway involving the mannose-binding lectin-associated serine protease 2 (MASP-2) has been shown to be an important mediator of the inflammatory response in ischaemia/reperfusion injury in the heart. In this study, therefore, we aimed to investigate the feasibility of using monoclonal antibodies raised against MASP-2 in a murine model of AMI.

Methods

Mice were injected with anti-MASP-2 antibody or control 18 hours prior to experimental infarction by ligation of the left anterior descending coronary artery for 30 min followed by 120 min reperfusion. The developed infarct was measured, and blood was collected for analysis of lectin pathway functional activity.

Results and conclusions

We found that mice treated with anti-MASP-2 antibody had smaller infarcts than those treated with control antibody. We believe this may represent a valuable step forward in the protection of the myocardium against ischaemia-reperfusion injury.

[Cardiac remodeling after myocardial infarction : Clinical practice update]

Heart failure remains a frequent cause of death and is the leading reason for hospitalization in Germany although therapeutic options have significantly increased over the past years particularly in heart failure with reduced ejection fraction. Clinical symptoms are usually preceded by cardiac remodeling, which was originally defined only by left ventricular dilatation and depressed function but is also associated with typical cellular and molecular processes. Healing after acute myocardial infarction is characterized by inflammation, cellular migration and scar formation. Cardiac remodeling is accompanied by adaptive changes of the peripheral cardiovascular system. Since prevention is the primary goal, rapid diagnosis and treatment of myocardial infarction are mandatory. Early reperfusion therapy limits infarct size and enables the best possible preservation of left ventricular function. Standard pharmacotherapy includes angiotensin-converting enzyme inhibitors, angiotensin-1-receptor blockers and beta blockers. In addition, mineralocorticoid receptor antagonists have proven beneficial. Compounds specifically targeting infarct healing processes are currently under development.

Randomized controlled trial of TY-51924, a novel hydrophilic NHE inhibitor, in acute myocardial infarction

BACKGROUND

In patients with ST-elevation acute myocardial infarction (STEMI), reperfusion therapy limits infarct size, but can directly evoke myocardial reperfusion injury. Activation of the Na(+)/H(+) exchanger (NHE) plays an important role in reperfusion injury. TY-51924, a novel NHE inhibitor, significantly reduced infarct size in animal studies and was well tolerated in early-phase clinical trials. This study aim was to evaluate the efficacy and safety of TY-51924 in patients with STEMI.

METHODS

In this multicenter, randomized, double-blind, placebo-controlled Phase II trial, 105 patients with first anterior STEMI undergoing primary percutaneous coronary intervention (pPCI) were randomly assigned to receive an intravenous infusion of either TY-51924 or placebo. Primary endpoints were myocardial salvage index (MSI) as determined by single photon emission computed tomography (SPECT) 3-5 days after pPCI and safety up to 7 days.

RESULTS

Baseline characteristics were similar in the two groups. MSI 3-5 days after pPCI (0.200 vs. 0.290, p=0.56), 3 months after pPCI (0.470 vs. 0.500, p=0.76), and the incidences of side effects did not differ between the two groups as a whole. However, on post hoc analysis of 52 patients with a large area at risk (AAR) (≥38%) and no antegrade coronary flow, MSI by SPECT at 3 months after pPCI was significantly higher in TY-51924 group (0.450 vs. 0.320, p=0.03). TY-51924 did not adversely influence hemodynamics.

CONCLUSIONS

TY-51924 did not improve MSI or increase side effects as a whole. However, TY-51924 is potentially cardioprotective in the presence of a large AAR and no antegrade coronary flow.

Prognostic significance of the distortion of terminal portion of QRS complex on admission electrocardiogram in ST segment elevation myocardial infarction

BACKGROUND

ECG on admission has been used in predicting prognosis and risk stratification in ST segment elevation acute myocardial infarction (STEMI).

OBJECTIVE

To analyze the admission ECG in STEMI based on abnormality observed in terminal portion of QRS and its correlation to hospital mortality.

METHOD

160 consecutive patients of STEMI were classified into subjects without (Group I) and with distortion of terminal QRS (Group II), Pattern A--Emergence of J point at ≥50% of the R wave amplitude in leads with qR configuration or Pattern B--Absence of the S waves, in leads with Rs configuration in two consecutive leads.

RESULTS

Out of 160 patients of STEMI, 69 (43.1%) had distortion of QRS. There were 13 deaths (8.1%). Hospital mortality was found to be significantly more in subjects with distortion than those without (15.9% V/S 2.1%, p < 0.001). Patients with QRS distortion tended to have larger infarction as assessed by Killip class on admission (p < 0.05), anterior location of MI (p < 0.01) and presence of significant Q waves in leads with ST segment elevation (p < 0.0001). With multiple logistic regression analysis using hospital mortality as a dependent variable and all studied risk factors as independent variables, QRS distortion on admission ECG was the only variable found to be statistically significant (Adjusted OR = 7.161, p < 0.05).

CONCLUSION

ECG on admission is a simple, cheap, universally available investigation that can predict the short term prognosis in STEMI and would help in deciding which patients should go for other myocardial revascularization procedures.

The presence of angiographic collaterals in non-ST elevation myocardial infarction is a predictor of long-term clinical outcomes

OBJECTIVES

To determine whether the presence of angiographic coronary collaterals is a predictor of long-term clinical outcomes in patients with non-ST elevation myocardial infarction (NSTEMI).

BACKGROUND

The presence of coronary collaterals on angiography provides prognostic information in patients with STEMI, but it is unknown whether they provide prognostic information in patients with NSTEMI.

METHODS

This was a prospective cohort study of 931 consecutive patients undergoing coronary angiography of which 269 (29%) had a NSTEMI. Baseline characteristics, angiographic details, and long-term clinical outcomes including death, recurrent MI, coronary artery bypass graft surgery (CABG), percutaneous coronary intervention (PCI), stroke, and congestive heart failure (CHF) were collected. Each clinical outcome as well as the combined endpoint of death, recurrent MI, CABG, PCI stroke and CHF was compared in subjects with and without collaterals.

RESULTS

At one year, individuals with collaterals had significantly increased rates of the combined endpoint compared with those without (25% vs. 16%, P = 0.0001). On multivariate analysis, the presence of collaterals was a strong predictor of the combined endpoint of death, recurrent MI, CABG, PCI, stroke and CHF (HR 1.95, CI 95% 1.08-3.52; P = 0.027). Similarly, in the subset of 115 patients (43%) in whom the culprit artery was identified, the presence of collaterals was a strong negative predictor (HR 3.71, CI 1.31-10.57, P = 0.014), driven by a 13-fold increase in subsequent CABG.

CONCLUSIONS

In patients with NSTEMI the presence of angiographic coronary collaterals is a predictor of long-term clinical outcomes primarily driven by increased rates of surgical revascularization.

The predictive value of an ECG-estimated Acute Ischemia Index for prognosis of myocardial salvage and infarct healing 3months following inferior ST-elevated myocardial infarction

BACKGROUND AND PURPOSE

Identification of prognostic markers can be used to stratify patients in the acute phase of ST-elevated myocardial infarction (STEMI) according to their potential to retain viable myocardium after reperfusion. The percentage of the myocardial area at risk (MaR) that is ischemic at admission, defined as the Acute Ischemia Index, is potentially salvageable. The percentage of the MaR viable at 3months post-reperfusion, by salvage and healing, was defined as the Chronic Salvage Index. A positive relationship between the Acute Ischemia Index and the Chronic Salvage Index was hypothesized.

METHODS

Both indices were assessed by using the ECG indices Aldrich ST and Selvester QRS scores estimating the ischemic and infarcted myocardium. The study population comprised inferior STEMI patients. (N=59).

RESULTS

A correlation of 0.253 (P=0.053) was found.

CONCLUSIONS

These results are relevant and suggest evidence of a trend in the association between these indices.

Prolonged door-to-balloon time: is treatment delayed always treatment denied?

Rapid reperfusion following the onset of ST-segment elevation myocardial infarction has been shown to provide life-saving benefit. Both systemic fibrinolytic therapy and percutaneous coronary intervention have been shown to be effective in reducing mortality, and their effectiveness is greater the sooner they are applied. Percutaneous coronary intervention has become the dominant method of reperfusion and may offer benefit over systemic fibrinolysis in some patients. Accordingly, physicians, hospitals, and professional organizations have developed guidelines and algorithms to both speed and standardize care. In addition, the institutional rapidity of therapy-the mean or median door-to-balloon time-is often publically reported providing further impetus to rapid triage and treatment of ST-segment elevation myocardial infarction. However, some patients do not receive reperfusion within the time guidelines set out by professional organizations. In many instances, this delay relates to medical issues that exist in addition to the patient's myocardial infarction. These data raise the question of whether the most rapid reperfusion is always superior to more delayed but potentially more comprehensive therapy.

Left ventricular function after ST-elevation myocardial infarction in patients treated with primary percutaneous coronary intervention and abciximab or tirofiban (from the Facilitated Angioplasty with Tirofiban or Abciximab [FATA] Trial)

Abciximab therapy during primary percutaneous coronary intervention (PCI) has shown to ameliorate left ventricular (LV) function recovery in patients with ST elevated myocardial infarction. High-dose bolus tirofiban has similar effect on platelet inhibition. Whether this is associated with comparable efficacy on LV function recovery remains unclear. We sought to evaluate the impact on LV function of high-dose bolus tirofiban or abciximab in patients undergoing primary PCI with the predictors of favorable (> or = 50%) LV ejection fraction (EF) and LV function recovery at 30 days. We studied 314 patients (abciximab n = 154; tirofiban n = 160) undergoing primary PCI in the randomized Facilitated Angioplasty with Tirofiban or Abciximab (FATA) Trial. LVEF was assessed within 48 hours and at 30 days after primary PCI. In patients with systolic dysfunction at baseline, LV function recovery was defined by either increase of LVEF > or = 10% compared with baseline or LVEF > or = 50%. Similar LVEF was observed in the 2 groups postprocedure (abciximab 49.7 +/- 10.1% vs tirofiban 49.3 +/- 10.1%, p = 0.9) and at 30 days (abciximab 53.1 +/- 9.8% vs tirofiban 52.5 +/- 10.2%, p = 0.6). Independent predictors of 30-day LVEF > or = 50% were preprocedure Thrombolysis In Myocardial Infarction flow class >0 (odds ratio = 2.4, 95% confidence interval 1.32 to 4.34), anterior location (odds ratio = 0.25, 95% confidence interval 0.15 to 0.42), and age (odds ratio = 0.97, 95% confidence interval 0.95 to 0.99). Preprocedure Thrombolysis In Myocardial Infarction flow grade >0 was the only predictor of LV function recovery (odds ratio = 6.73, 95% confidence interval 2.69 to 16.88). In conclusion, this study showed no difference in LV function recovery in patients undergoing primary PCI treated either with abciximab or high-dose bolus tirofiban. Preprocedure Thrombolysis In Myocardial Infarction flow grade >0 seems to be the most important predictor of favorable LVEF and LV function recovery at 30 days.

Preservation of myocardial viability within the risk area by intravenous nicorandil before primary coronary intervention in patients with acute myocardial infarction

OBJECTIVE

To investigate the cardioprotective effect of intravenous nicorandil before primary percutaneous coronary intervention (PCI) on preservation of myocardial viability, we studied 199 consecutive patients with acute myocardial infarction.

METHODS

Nicorandil was given intravenously on admission (before primary PCI). Echocardiography and technetium-99m tetrofosmin perfusion imaging were performed before and 1 month after primary PCI. Echocardiographic asynergic score before primary PCI was used to define the size of risk area, whereas the sum of scintigraphic defect grade before primary PCI was used to estimate myocardial viability within the area at risk. The change (before primary PCI and 1 month after primary PCI) in asynergic score and scintigraphic salvage index were calculated.

RESULTS

Patients were divided into nicorandil (n=101) and control (n=98) groups. Although asynergic score before primary PCI was not different between the two groups (nicorandil=3.5+/-2.1 and control=3.9+/-1.5), myocardial viability was preserved in nicorandil group (defect score=11.0+/-4.0) than that in control group (defect score=14.0+/-4.7, P<0.0001). Multivariate analysis revealed that the presence of antegrade flow (P=0.015) and nicorandil (P<0.0001) were independently associated with preserved myocardial viability before primary PCI. Moreover, the greater reduction in asynergic score (66+/-41 vs. 49+/-23%, P=0.0006) and larger salvage index (65+/-25 vs. 53+/-26%, P=0.0015) were observed in nicorandil group compared with the control group.

CONCLUSION

Intravenous administration of nicorandil before primary PCI preserved myocardial viability within the risk area, which leads to greater myocardial salvage and better functional recovery after primary PCI.

Correlates of bundle-branch block in patients undergoing primary angioplasty for acute myocardial infarction

BACKGROUND

Early reperfusion therapy has reduced the infarct size and mortality rate in patients with acute myocardial infarction (AMI). The occurrence of bundle-branch block in AMI is related to the amount of myocardial damage and the insult to the conduction system.

HYPOTHESIS

To evaluate the clinical and angiographic factors related to the occurrence of bundle-branch block (BBB) in patients with primary percutaneous transluminal coronary angioplasty (PTCA), we investigated consecutive series of patients with their first Q-wave AMI and successful PTCA.

METHODS

Coronary angiogram at the time of admission, electrocardiogram, and echocardiogram were evaluated in 279 patients with their first Q-wave AMI and successful PTCA.

RESULTS

Bundle-branch block was detected in 26 patients (9%); 16 patients had transient and 10 patients had persistent block, while 16 patients had bifascicular block and 10 patients had right BBB. The patients with BBB had a significantly larger number of left ventricular asynergic segments, higher incidence of total occlusion of infarct-related artery, angiographic no reflow, and pericardial rub than those without BBB. When the multivariate analysis was performed using five clinical markers of infarct severity, angiographic no reflow (F = 20.2, p < 0.001) and total occlusion of infarct-re-lated artery (F = 4.2, p = 0.04) were found to be the significant variables related to BBB.

CONCLUSIONS

Despite successful primary PTCA, absence of antegrade flow in the infarct-related artery at the onset of AMI and/or angiographic no reflow resulted in more severe transmural myocardial damage and, hence, the occurrence of BBB.

Guidelines for therapy of ST-segment-elevation acute myocardial infarction in patients presenting to Partners Healthcare system hospital emergency departments

A major focus for individuals and organizations that study the quality of cardiovascular care is the timeliness of treatment for those patients who suffer an acute ST-elevation myocardial infarction (STEMI). We sought to develop guidelines that would inform the development and management of a more standardized approach to the treatment of STEMI within the 5 acute care hospitals that make up the Partners Healthcare acute care hospital network. In recent years much has been learned about how to deliver timely reperfusion therapy in STEMI and how to assess its outcome. As a component of the organization's mandate to promote the uniform high quality of care throughout the system, our group began studying the many aspects of the current treatment of STEMI within the system, we reviewed, summarized and debated the relevant literature, studied best practices and made recommendations for a system-wide approach to this problem. Our methods have included literature review, consultation with local and national experts, site visits throughout the system, web-based surveys of current attitudes within the system, interviews with stakeholders and consensus-development conferences. The result was not only the development of the following guidelines for therapy, but also an ongoing commitment to share patient-level data and outcomes for continuous quality assessment and improvement.

Impact of collateral flow on myocardial reperfusion and infarct size in patients undergoing primary angioplasty for acute myocardial infarction

BACKGROUND

The prognostic impact of baseline collateral flow of the infarct-related artery (IRA) in patients undergoing primary percutaneous coronary intervention (PCI) remains controversial. We sought to examine the impact of baseline collateral flow to the IRA on reperfusion success, infarct size, and clinical outcomes in patients undergoing primary PCI for acute myocardial infarction (AMI).

METHODS AND RESULTS

Acute procedural, 30-day, and 6-month clinical outcomes were assessed after primary PCI among patients enrolled in the EMERALD trial (n = 501 with AMI within 6 hours of onset). Patients with collateral flow to the IRA (Rentrop grade 2 or 3) more commonly had prior stable angina, less commonly had failed thrombolysis and left anterior descending artery occlusion, and presented with less ST-segment elevation. Myocardial reperfusion assessed by ST-segment recovery and myocardial blush was similar in patients with and without baseline collateral flow to the IRA. Infarct size (assessed by technetium Tc 99m sestamibi) was similar among patients with and without baseline collateral flow in anterior infarction (mean 28.5% vs 31.2%, respectively; P = .59) and nonanterior infarction (12.5% vs 12.1%, respectively; P = .81). There were no differences in the rates of major adverse cardiac events at 30 days or 6 months according to baseline IRA collateral flow.

CONCLUSIONS

Among patients undergoing primary PCI for AMI within 6 hours of symptom onset, we found no significant relationship between baseline collateral flow and either reperfusion success, infarct size, or subsequent clinical outcomes.

Impact of time to treatment on myocardial reperfusion and infarct size with primary percutaneous coronary intervention for acute myocardial infarction (from the EMERALD Trial)

The impact of time to treatment on outcomes after primary percutaneous coronary intervention (PCI) is controversial, and there are few data about time to treatment and infarct size. The EMERALD trial randomly assigned 501 high-risk patients with ST-elevation myocardial infarction undergoing primary PCI to stenting with or without GuardWire (Medtronic, Santa Rosa, California) distal protection. Infarct size using sestamibi imaging at 5 to 14 days and clinical outcomes were examined by time to treatment. There were no differences in outcomes between distal protection and control patients. Shorter time to reperfusion (<2 vs 2 to 3 vs >3 to 4 vs >4 hours) was associated with smaller infarct size (2% vs 9% vs 12% vs 11%, p=0.026), trends for better myocardial blush (p=0.08), and lower 6-month mortality rates (0% vs 0% vs 2.4% vs 5.3%, p=0.06). Incremental delays in reperfusion after 2 hours had little impact on infarct size. Shorter time to reperfusion impacted on infarct size in patients with anterior infarction (0% vs 17% vs 20.5% vs 30.5%, p=0.026), but not nonanterior infarction (3% vs 7% vs 7.5% vs 10%, p=0.23, p=0.022 for interaction). In conclusion, very early reperfusion with primary PCI is associated with smaller infarct size and has a much greater impact in anterior versus nonanterior infarction. Incremental delays in reperfusion after 2 hours have less effect on infarct size. These data have implications regarding the triage of patients for primary PCI.

The effects of facilitated primary PCI by guide wire on procedural and clinical outcomes in acute ST-segment elevation myocardial infarction

BACKGROUND

Reperfusion of the infarct related artery (IRA) prior to PCI is prognostically important in patients with acute ST segment elevation myocardial infarction (STEMI). Reperfusion is either achieved spontaneously, facilitated by GP IIb/ IIIa inhibitors, or mechanically by crossing the guide wire beyond the lesion. In order to test the hypothesis that a visible coronary anatomy is independently associated with procedural and clinical outcomes, we evaluated the frequency and prognostic impact of guide wire facilitated reperfusion of the IRA before primary PCI.

METHODS AND RESULTS

We enrolled 311 consecutive patients with successful primary PCI for STEMI (TIMI grade > or =2 flow) within 12 h after onset of symptoms. Among these, 90 patients (28.9%) had a spontaneously reperfused IRA on initial angiogram, 56 patients (18.0%) achieved reperfusion after crossing of the guide wire, and 165 patients (53.1%) successful reperfusion only after PCI. Variables associated with successful guide wire facilitated reperfusion were younger age, no history of arterial hypertension, active smoking status, negative cardiac troponin T on admission, and an infarct in the territory of the right coronary artery. Patients with spontaneous reperfusion or reperfusion after crossing of the guide wire required less fluoroscopic time and less contrast material during angiography and had higher procedural success rates (TIMI grade 3 flow 91.1 vs 79.4%, p=0.048) than patients without initial reperfusion. In addition, patients with reperfusion after crossing the lesion with the guide wire had lower mortality rates at 30 days (3.6 vs 9.1%) and after a median of 16 months (3.6 vs 13.9%, p=0.03) than those with reperfusion after PCI.

CONCLUSIONS

Reperfusion of an occluded IRA by crossing the guide wire is associated with higher procedural success rates and better outcomes. Better roadmapping and device selection represent potential reasons but the exact mechanism for these benefits is still illusive.

Residual flow to the infarct zone against lethal ventricular tachyarrhythmias during the acute phase of myocardial infarction

BACKGROUND

The benefits of residual flow to the infarct zone have been demonstrated in acute myocardial infarction (AMI), but its relation to ventricular tachyarrhythmias remains uncertain.

HYPOTHESIS

This study was undertaken to test the hypothesis that residual flow is an important determinant of lethal ventricular tachyarrhythmias (sustained ventricular tachycardia or ventricular fibrillation) during the acute phase of AMI.

METHODS

We investigated the determinants of lethal ventricular tachyarrhythmias within 24 h after the onset of symptoms in 310 consecutive patients (256 men; age 57.4 +/- 11.5 years) with AMI undergoing primary angioplasty. Patients were divided into two groups: those with (Group 1, n = 40) and those without (Group 2, n = 270) lethal ventricular tachyarrhythmias. Residual flow was defined as the presence of anterograde flow (> or = Thrombolysis in Myocardial Infarction [TIMI] 2 flow) or good angiographic collaterals (> or = grade 2) on a preintervention angiogram.

RESULTS

Univariate determinants of lethal ventricular tachyarrhythmias were cardiogenic shock, systolic blood pressure, peak level of creatine kinase, culprit artery, spontaneous reperfusion, and residual flow. In multivariate analysis, however, cardiogenic shock (odds ratio [OR] = 4.79, 95% confidence interval [CI] 1.63-14.11, p = 0.004), residual flow (OR = 0.34, 95% CI 0.14-0.81, p = 0.015), and the right coronary artery as the culprit artery (OR = 2.09,95% CI 1.03-4.22, p = 0.040) were independent determinants of these arrhythmias. In-hospital death occurred in 10 patients and was more common in Group 1 than in Group 2 (12.5% vs. 1.9%, respectively, p < 0.001).

CONCLUSION

The absence of residual flow was associated with greater risk of lethal ventricular tachyarrhythmias during the acute phase of AMI, suggesting a protective role of residual flow against these arrhythmias in AMI.

The effect of verapamil on the restoration of myocardial perfusion and functional recovery in patients with angiographic no-reflow after primary percutaneous coronary intervention

OBJECTIVE

Angiographic thrombolysis in myocardial infarction (TIMI) flow grade < or = 2 after primary percutaneous coronary intervention (PCI), defined as angiographic no-reflow, predicts poor functional recovery in patients with acute myocardial infarction. We investigated the effect of verapamil on the restoration of myocardial perfusion and functional recovery in patients with angiographic no-reflow after PCI.

METHODS

99mTc tetrofosmin single photon emission computed tomographic (SPECT) imaging was performed (before, immediately after and 1 month after PCI) in 101 consecutive patients with acute myocardial infarction. The defect score was calculated as the sum of perfusion defect in a 13-segment model (scores of 3, complete defect to 0, normal perfusion). The asynergic score, defined as the number of asynergic segments, was assessed by echocardiography before and 1 month later. Multiple logistic regression analysis was performed to elucidate the effect of verapamil administration.

RESULTS

Of 101 patients, 32 (31%) had angiographic no-reflow and were divided into two groups: 18 patients with verapamil (group 1) and 14 patients without verapamil (group 2). Sixty-nine patients had TIMI grade 3 reflow after PCI (group 3). The change in the defect score 1 month after PCI in group 1 was significantly larger than that in group 2 (P = 0.003). The asynergic score improved more at 1 month in group 1 compared to that in group 2 (P = 0.007). Moreover, logistic regression analysis revealed that TIMI grade reflow < or = 2 after PCI (P = 0.04, OR = 5.51), the defect score before PCI (P = 0.03, OR = 1.15), the asynergic score before PCI (P = 0.01, OR = 0.64) and the administration of verapamil (P = 0.002, OR = 22.4) were independently associated with successful myocardial reperfusion immediately after PCI.

CONCLUSIONS

Intracoronary verapamil restored myocardial perfusion in patients with angiographic no-reflow after PCI and lead to better functional recovery after acute myocardial infarction.

Impact of coronary collaterals on outcome following percutaneous coronary intervention (from the National Heart, Lung, and Blood Institute Dynamic Registry)

Coronary collateral circulation is beneficial in patients with coronary artery disease, but controversy still exists regarding the association between angiographic collaterals and outcome after percutaneous coronary intervention (PCI). We compared the baseline characteristics and cumulative 1-year event rates of consecutive patients undergoing PCI by target vessel collateral status-no angiographic evidence of collateral circulation (NC; n = 5051), treated artery supplied collaterals (SC; n = 239), and treated artery received collaterals (RC; n = 893)-using the National Heart, Lung, and Blood Institute Dynamic Registry. Patients in the SC group were older and had more previous coronary bypass surgery, myocardial infarction, co-morbid illness, and heart failure than the NC and RC groups and had less often undergone revascularization for acute myocardial infarction (p <0.01 for all). The total angiographic PCI success was comparable for the SC and NC groups but higher than for the RC group (94.1% vs 94.4% vs 83.9%, respectively; p <0.001). Overall stent use was 77.5% and was highest in the SC group (82.4%, p <0.001). At 1 year, significant differences in outcome were observed by collateral status. Compared with the NC group, patients with PCI of a SC artery had higher adjusted mortality (relative risk [RR] 1.95, 95% confidence interval [CI] 1.27 to 3.01, p = 0.002) and death/myocardial infarction (RR 1.75, 95% CI 1.26 to 2.45, p <0.001) rates. Patients with PCI of a RC vessel, conversely, had lower adjusted death/myocardial infarction (RR 0.72, 95% CI 0.54 to 0.96, p = 0.02) and repeat revascularization (RR 0.73, 95% CI 0.59 to 0.91, p = 0.005) rates. In conclusion, our results suggest that PCI on collateralized vessels is warranted, but that patients with PCI in arteries that supply collaterals are a high-risk group that may benefit from closer follow-up and complete revascularization.

Clinical factors associated with persistent pericardial effusion after successful primary coronary angioplasty

STUDY OBJECTIVE

To evaluate the incidence and clinical factors related to the persistence of infarct-associated pericardial effusion (PE) after primary angioplasty.

DESIGN

Consecutive case-series analysis.

SETTING

Coronary care unit in a university hospital.

PATIENTS

Three hundred ninety-one consecutive patients with acute myocardial infarction (AMI) who underwent successful primary percutaneous transluminal coronary angioplasty (PTCA) at hospital admission.

INTERVENTIONS

Coronary angiography and primary PTCA on hospital admission and serial echocardiography.

MEASUREMENTS AND RESULTS

The status of coronary flow before and after primary PTCA was evaluated by coronary angiography at hospital admission, while PE was studied by echocardiography within 24 h of admission and 1 month after the onset of AMI. PE was present in the acute phase in 76 patients (19%), and patients with PE had a significantly higher incidence of in-hospital death than those without PE (11% vs 2%, p < 0.001). Among 68 patients who had PE in the acute phase and underwent echocardiography 1 month later, PE persisted to 1 month after the onset of AMI (persistent PE) in 26 patients (38%). Patients with persistent PE had a significantly higher incidence of pericardial rub (p = 0.010), Killip class > 1 (p = 0.025), no reflow after PTCA (p = 0.026), lower incidence of collaterals (p = 0.024), and tended to have higher peak creatine kinase (CK) [p = 0.05] levels than those with transient PE. When five variables (peak CK, collaterals, no reflow, pericardial rub, and Killip class > 1) were used in the multivariate analysis, pericardial rub (p = 0.023; odds ratio [OR], 5.45), absence of collaterals (p = 0.011; OR, 0.16), and Killip class > 1 (p = 0.027; OR, 3.80) were the significant variables related to persistent PE.

CONCLUSIONS

PE remains a relatively common complication of AMI even in the era of reperfusion therapy and is associated with increased mortality. Furthermore, the presence of a pericardial rub, Killip class > 1, and absence of collateral flow in the early phase of the infarct are associated with persistence of the PE to 1 month after the onset of AMI.

Myocardial contrast echocardiography assessment of acute changes in collateral perfusion of contralateral coronary artery with coronary flow reserve after coronary angioplasty

BACKGROUND

Coronary flow velocity reserve (CFVR) is used to evaluate the severity of epicardial and intramyocardial coronary artery disease. Collateral flow to an adjacent compromised myocardial territory may influence the CFVR of a specific artery.

METHODS

To assess the impact of collateral flow on CFVR, we measured CFVR and assessed perfusion area (PA) with myocardial contrast echocardiography in the right coronary arteries of 18 patients with total/subtotal occlusion of the left anterior descending coronary artery before and after angioplasty. A total of 10 patients had well-developed collaterals emerging from the right coronary artery (group I) and 8 patients did not (group II). Using a Doppler-tipped guidewire, we measured CFVR, which is defined as the ratio of papaverine-induced hyperemic average peak velocity of coronary flow to baseline.

RESULTS

Before angioplasty of the left anterior descending coronary artery, CFVR was significantly reduced in group I compared with group II (2.35 +/- 0.47 vs 3.26 +/- 0.54, P < .01). Baseline average peak velocity in group I before angioplasty was significantly greater than that after angioplasty (23.7 +/- 11.6 vs 19.2 +/- 9.7 cm/s, P < .05). After angioplasty, CFVR immediately increased in group I to 3.46 +/- 0.54 ( P < .001). The increase in CFVR was well correlated with the decrement in PA after angioplasty (r = 0.883, P < .001).

CONCLUSION

The CFVR of an artery that supplies extensive collaterals is limited because of an elevation in the baseline resting flow velocity. This restriction in CFVR improves proportionally with decreases in PA that occurs after angioplasty of the ipsilateral coronary artery. These data suggest that PA, in addition to coronary artery structure, influences CFVR.

Grade 3 ischemia on the admission electrocardiogram predicts rapid progression of necrosis over time and less myocardial salvage by primary angioplasty

BACKGROUND

Among patients with ST-elevation acute myocardial infarction, those with terminal QRS distortion (grade 3 ischemia) have higher mortality and larger infarct size (IS) than patients without QRS distortion (grade 2 ischemia).

METHODS

We assessed the relation of baseline electrocardiographic ischemia grades to area at risk (AR) and myocardial salvage [100 (AR-IS)/AR] in 79 patients who underwent primary angioplasty for first ST-elevation acute myocardial infarction and had technetium Tc 99m sestamibi single-photon emission computed tomography before angioplasty (AR) and at predischarge (IS). Patients were classified as having grade 2 ischemia (ST elevation without terminal QRS distortion in any of the leads, n = 48), grade 2.5 ischemia (ST elevation with terminal QRS distortion in 1 lead, n = 16), or grade 3 ischemia (ST elevation with terminal QRS distortion in >2 adjacent leads, n = 15).

RESULTS

Time to treatment was comparable among groups. AR was comparable among groups (38% +/- 20%, 33% +/- 23%, and 34% +/- 23%, respectively; P = .70). There were no differences among groups in residual myocardial perfusion (severity index 0.28 +/- 0.12, 0.29 +/- 0.16, and 0.30 +/- 0.15 in grades 2, 2.5, and 3 ischemia, respectively; P = .97). In contrast, there was a trend toward lower myocardial salvage (45% +/- 32%) in the grade 3 group than in the grade 2 (65% +/- 33%) and grade 2.5 (65% +/- 40%) groups ( P = .16). Salvage was dependent on time only in the grade 3 group. Spearman rank correlation coefficients between time to treatment and percentage salvage were 0.003 ( P = .99), -0.24 ( P = .38), and -0.63 ( P = .022) for grades 2, 2.5, and 3, respectively.

CONCLUSIONS

Patients with grade 3 ischemia have rapid progression of necrosis over time and less myocardial salvage. This admission pattern is a predictor of myocardial salvage by primary angioplasty.

Angiographic perfusion score: an angiographic variable that integrates both epicardial and tissue level perfusion before and after facilitated percutaneous coronary intervention in acute myocardial infarction

BACKGROUND

Both epicardial and myocardial perfusion have been associated with clinical outcomes in the setting of ST elevation myocardial infarction (STEMI), and the performance of adjunctive/rescue percutaneous coronary intervention (PCI) may further improve clinical outcomes after fibrinolytic administration.

METHODS

The goal was to develop a simple, broadly applicable angiographic metric that takes into account indices of epicardial and myocardial perfusion both before and after PCI to arrive at a single perfusion grade in patients undergoing cardiac catheterization after fibrinolysis. The angiographic perfusion score (APS) is the sum of the Thrombolysis in Myocardial Infarction (TIMI) flow grade (TFG; 0-3) added to the TIMI myocardial perfusion grade (TMPG; 0-3) before and after PCI (total possible grade, 0-12). Failed perfusion was defined as an APS of 0 to 3, partial perfusion was defined as an APS of 4 to 9, and full perfusion was defined as an APS of 10 to 12. The APS was evaluated in patients from the Double-blind, Placebo-contolled, Multicenter Angiographic Trial of Rhumab CD18 in Acute Myocardial Infarction (LIMIT-AMI; n = 394) and Enoxaparin as Adjunctive Antithrombin Therapy for ST-Elevation Myocardial Infarction-Thrombolysis In Myocardial Infarction (ENTIRE-TIMI) 23 trials (n = 483), and infarct size (120-216 hours after AMI SPECT Technetium-99m Sestamibi data) was assessed in the LIMIT-AMI trial.

RESULTS

The APS was associated with the incidence of death or myocardial infarction (failed, 16.7% [n = 18]; partial, 2.5% [n = 155]; full, 2.4% [n = 82]; P =.039 for trend) and larger SPECT infarct sizes (failed, median 39% [n = 10]; partial, 12% [n = 79]; and full, 8% [n = 35]; P =.002). No patient with full APS died, whereas the mortality rate was 11.1% in patients with a failed APS (P =.03).

CONCLUSIONS

The APS combines grades of epicardial and tissue level perfusion before and after PCI or at the end of diagnostic cardiac catheterization to arrive at a single angiographic variable that is associated with infarct size and the rates of 30-day death or MI. Partial or full angiographic perfusion scores are associated with a halving of infarct size, and no patients with full angiographic perfusion died.

Blood flow velocity in donor coronary artery depends on the degree and pattern of collateral vessel development: A study using thrombolysis in myocardial infarction frame count method

To understand the influence of collateral vessels on the coronary flow, TIMI frame count (TFC) method was applied as a measure of mean coronary blood flow velocity in artery giving collateral blood supply to the other artery in angiograms of 76 patients with single occluded coronary artery: RCA giving collaterals to occluded LAD or LAD giving collaterals to occluded RCA. As a control group, TFC was applied in angiograms of 30 patients with mild or no coronary artery disease. TFC was lower (faster blood flow) in LAD giving collaterals to occluded RCA (43 patients) than in LAD in control group (21.8 +/- 10.5 vs. 33.9 +/- 20.8 frames; P < 0.01). Higher degree of collateral vessels (Rentrop classification) and mixed- and distal-type collaterals (through the interventricular septum and heart apex) was associated with lower TFC. There was no difference in TFC in the RCA giving collaterals to an occluded LAD (33 patients) compared to the TFC in RCA in control group (16.6 +/- 9.0 vs. 18.5 +/- 6.0; P = NS), even in angiograms with higher degree of collateral vessel development. TFC was lower (faster blood flow) only in subgroups with mixed (proximal and distal types together in the same patient) and distal (through the interventricular septum and the apex of the heart) collateral types. A delayed contrast appearance in occluded LAD compared to occluded RCA has been found (35.1 +/- 16.1 vs. 20.2 +/- 7.3 frames; P < 0.001) with earlier contrast appearance in occluded LAD when proximal collateral vessels (through the conal and acute marginal branches of RCA) were presented. The coronary flow in donor arteries depends not only on the degree but also on the pattern of collateral vessels. The simple TFC method may facilitate the study of collateral filling pattern and offer insight into the influence of collaterals on the ventricular function.

Statin use is associated with enhanced collateralization of severely diseased coronary arteries

BACKGROUND

The presence of coronary collateral vessels has been associated with improved clinical outcome in patients with coronary artery disease. Animal experiments have shown that hydroxymethyl glutaryl coenzyme A reductase inhibitors (statins) can promote angiogenesis in ischemic tissues in a cholesterol-independent manner. We hypothesized that statin therapy is associated with increased coronary collateral formation in patients with severe coronary artery disease.

METHODS AND RESULTS

Patients undergoing clinically indicated coronary angiography at the Tufts-New England Medical Center from September 2000 to April 2001 who had at least 1 major coronary artery occlusion, or a stenosis of > or =95% with Thrombolysis In Myocardial Infarction (TIMI) trial grade < or =1 anterograde flow on their angiograms, were included. Fifty-one patients were taking statins before admission, and 43 patients were not. Their angiograms were reviewed and coronary collaterals were graded from 0 to 3 according to the Cohen-Rentrop method. The statin-treated group had a significantly higher mean collateral score compared with the patients not taking statins (2.05 vs 1.52, P =.005). Multivariate analysis supported the significance of the effect of statin therapy on the collateral score. There was no relation between collateral score and low-density lipoprotein levels (r = -0.06, P =.64). The statin-treated group also had a significantly higher left ventricular ejection fraction compared to the patients not taking statins (51% vs 44%, P <.05).

CONCLUSIONS

Statin therapy is associated with enhanced coronary collateral formation in patients with severely diseased coronary arteries.

Left ventricular free wall rupture after reperfusion therapy for acute myocardial infarction

We evaluated the clinical significance of angiographic indexes and pericardial involvement in predicting increased risk of free wall rupture after reperfusion therapy and found that Thrombolysis In Myocardial Infarction (TIMI) <3 flow grade after reperfusion therapy was a significant variable related to the free wall rupture. Moreover, pericardial rub was found to be a significant variable related to TIMI <3 grade flow after reperfusion, which indicates that detection of pericardial rub is one of the clinical signs that predicts inadequate anterograde flow of the infarct-related artery after reperfusion and hence, higher risk for free wall rupture.

Evidence for association of coronary sinus levels of hepatocyte growth factor and collateralization in human coronary disease

The therapeutic use of angiogenic factors to protect ischemic myocardium is limited by our incomplete understanding of their endogenous production. We determined the association between angiogenic factors and collateral formation in patients with coronary artery disease (CAD). A total of 71 patients underwent catheterization with sampling of the pulmonary artery, aorta, and coronary sinus (CS) to determine the levels of vascular endothelial growth factor (VEGF) and hepatocyte growth factor (HGF). VEGF and HGF levels were not different in the three vascular sites, suggesting that the heart is not a major source of these cytokines in the circulation. CS VEGF and HGF levels were similar in patients with and without CAD. Elevated CS HGF levels were associated with collateral formation, whereas VEGF levels were not. Additionally, CS HGF was significantly elevated in patients with left ventricular dysfunction. These data map for the first time the concentration of endogenous angiogenic factors in the coronary circulation and support further studies to determine whether HGF may be an endogenous cardioprotective angiogenic factor.

Quantitative estimation of myocardial salvage after primary percutaneous transluminal coronary angioplasty in patients with angiographic no reflow

Angiographic Thrombolysis in Myocardial Infarction (TIMI) flow grade <or=2 after primary percutaneous transluminal coronary angioplasty (PTCA), defined as angiographic no reflow, predicts poor left ventricular functional recovery and survival in patients with acute myocardial infarction (MI). To determine the relation between angiographic coronary flow and myocardial salvage in the acute phase of MI, serial technetium-99m tetrofosmin imaging was performed before, immediately after and 1 month after PTCA in 117 patients. Angiographic no reflow was observed in 23 patients (20%; group 1), while 94 patients did not have angiographic no reflow (group 2). Although there was no significant difference in the defect score before PTCA between the two groups (group 1, 14.4+/-5.7; group 2, 13.5+/-4.6), the defect score immediately after PTCA in group 1 was significantly higher than that in group 2 (group 1, 12.8+/-5.1; group 2, 8.9+/-4.6; P<0.0001). A significantly smaller change in the defect score after PTCA (before minus immediately after PTCA) was observed in group 1 as compared with group 2 (group 1, 1.7+/-2.0; group 2, 4.5+/-2.9; P<0.0001). Twenty patients in group 1 (87%) had impaired myocardial reperfusion (<4 change in the defect score immediately after PTCA), as compared with 36 patients (38%) in group 2; this difference was significant (chi(2)=17.5, P<0.0001). The sensitivity, specificity and accuracy of angiographic no reflow in estimating impaired myocardial reperfusion were 36%, 95% and 67%, respectively. Thus, angiographic no reflow is a highly specific, although not sensitive, marker of impaired myocardial reperfusion immediately after primary PTCA.

Myocardial viability, coronary flow reserve, and in-hospital predictors of late recovery of contractility following successful primary stenting for acute myocardial infarction

OBJECTIVE

To assess the relation between myocardial viability, coronary flow reserve, and recovery of myocardial contractility after stenting for acute myocardial infarction.

DESIGN

Consecutive sample prospective study.

SETTING

University hospital.

PATIENTS

41 patients with single vessel disease and successful primary stenting for a first acute myocardial infarction.

INTERVENTIONS

(201)Tl single photon emission computed tomography, contrast ventriculography, and intracoronary Doppler performed 7 (1) days after primary stenting.

MAIN OUTCOME MEASURES

Regional contractility recovery assessed by contrast ventriculography at 6 (1) months' follow up.

RESULTS

On univariate analysis, contractility recovery was correlated to prereperfusion anterograde and collateral flow grades (r = 0.41, p = 0.03 and r = 0.55, p = 0.0004), viability index (r = 0.55, p = 0.04), peak creatine kinase concentrations (r = -0.55, p = 0.0005), left ventricular ejection fraction (r = 0.45, p = 0.005), end diastolic pressure (r = -0.62, p < 0.0001), end systolic volume index (r = -0.47, p = 0.01), and the extent of hypokinetic area (r = -0.48, p = 0.003), but not the coronary flow reserve. On multivariate analysis, independent predictors of late contractility recovery were prereperfusion anterograde and collateral flow grades and viability index. Relative coronary flow reserve, reflecting the culprit vessel's microvascular function, was correlated only to the extent of the infarct risk area (r = -0.45, p = 0.003).

CONCLUSIONS

Independent predictors of contractility recovery between the seventh day and the sixth month after successful stenting for acute myocardial infarction are prereperfusion anterograde and collateral flows and myocardial viability. The culprit vessel's microvascular dysfunction is independent of myocardial viability and contractility and correlated to the extent of "jeopardised microvasculature".

Clinical significance of coronary flow to the infarct zone before successful primary percutaneous transluminal coronary angioplasty in acute myocardial infarction

STUDY OBJECTIVE

To assess the effect of coronary flow to the infarct zone before primary coronary angioplasty on hospital complications in patients with acute myocardial infarction (MI).

DESIGN

Consecutive case series analysis.

SETTING

Coronary-care unit in a university hospital.

PATIENTS

Two hundred sixty-four consecutive patients with ST-elevation acute MIs who had successful primary percutaneous transluminal coronary angioplasty.

INTERVENTIONS

Coronary angiography on hospital admission and serial echocardiography.

MEASUREMENTS AND RESULTS

The status of infarct-related artery flow before primary angioplasty was evaluated on hospital admission. Left ventricular wall motion and pericardial effusions were studied by echocardiography. One hundred ninety patients had total occlusions (Thrombolysis in Myocardial Infarction [TIMI] flow grade, 0 to 1) in the infarct-related artery (group 1), and 74 patients had antegrade flow (TIMI flow grade, 2 to 3) [group 2] before undergoing primary angioplasty procedures. When group 1 was subdivided into two groups (for the presence and absence of collateral flow), the patients with total occlusions and no collateral flow had a higher incidence of left ventricular aneurysmal wall motion (11% vs 1%, respectively; p = 0.03) and pericardial friction rub (15% vs 3%, respectively; p = 0.03) than did those in group 2. Moreover, those patients with total occlusions and no collateral flow had higher incidences of pericardial effusion (34% vs 17%, respectively; p = 0.02; and 34% vs 9%, respectively; p < 0.01) and in-hospital mortality (8% vs 1%, respectively; p = 0.04; and 8% vs 1%, respectively; p = 0.06) than did those patients in the other two groups.

CONCLUSIONS

Despite successful primary angioplasty, the absence of antegrade flow in the infarct-related artery and collateral flow to the infarct zone before angioplasty resulted in a higher incidence of in-hospital complications.

A nonischemic electrocardiogram does not always predict a small myocardial infarction: results with acute myocardial perfusion imaging

BACKGROUND

A nonischemic electrocardiogram (ECG) in association with myocardial infarction (MI) indicates a small MI in some but not all cases. Myocardial perfusion imaging using technetium-99m sestamibi offers the ability to better characterize these "electrically silent" infarctions.

METHODS

Patients considered low risk for myocardial infarction with a normal or nonischemic ECG (no significant ST elevation, ST depression, ischemic T-wave inversion, or left bundle branch block) underwent early emergency department perfusion imaging, followed by serial myocardial marker sampling. Risk area (defect size) was quantitated by use of a 50% threshold from multiple short-axis slices.

RESULTS

A total of 87 patients with nonischemic ECGs had myocardial infarction (mean peak creatine kinase [CK] 710 +/- 720 U/L, range 111-3196 U/L). Peak CKs were lower in the 7 patients with negative perfusion imaging (420 +/- 290 U/L vs 730 +/- 740 U/L, P =.06). Mean risk area was 18% +/- 11% of the left ventricle (range 0%-62%) and was not significantly different among the different infarct-related arteries. Patients with normal ECGs had a similar risk area compared with other patients (16% +/- 12% vs 19 +/- 12%, P =.25). Coronary angiography was performed in 81 patients, with significant stenoses in 74 (91%) (37 one-vessel, 19 two-vessel, 18 three-vessel), with the infarct related artery most commonly the left circumflex (n = 32 [38%]).

CONCLUSIONS

The ischemic risk area in patients with a nonischemic ECG was comparable to patients with inferior ST-elevation myocardial infarction found in previous studies. A nonischemic ECG does not predict a small ischemic risk area.

Functional significance of recruitable collaterals during temporary coronary occlusion evaluated by 99mTc-sestamibi single-photon emission computerized tomography

OBJECTIVES

The present study evaluated the impact of recruitable collaterals on regional myocardial perfusion measured by 99mtechnetium (Tc)-sestamibi single-photon emission computerized tomography (SPECT) during temporary coronary occlusion and related these estimates to the coronary wedge pressure and electrocardiographic (ECG) ST-segment changes.

BACKGROUND

Clinical variables (angina and ECG changes) and intracoronary flow and pressure recordings have indicated a protective role of recruitable collaterals on myocardial perfusion during percutaneous transluminal coronary angioplasty (PTCA).

METHODS

Thirty patients (mean age 55 years, SD 9; 20 men) with stable angina pectoris and proximal nonocluding single-vessel left anterior descending coronary artery (LAD)-stenosis scheduled for PTCA were included. Visualization of recruitable collaterals by ipsilateral and contralateral contrast injection, registration of coronary wedge pressure and injection of 99mTc-sestamibi during 90-s LAD occlusions were undertaken. A rest perfusion study was performed within four days before PTCA. As an estimate of the severity of regional hypoperfusion during occlusion, an occlusion/rest count ratio was calculated (mean defect pixel count during occlusion divided by mean pixel count in identical regions at rest).

RESULTS

The scintigraphic occlusion/rest count ratio was higher in patients with recruitable collaterals (n = 16), 67 +/- 11%, compared to patients without collaterals (n = 14), 60 +/- 6% (p < 0.05). The occlusion/rest count ratio correlated with the coronary wedge pressure (R2 = 0.34; p < 0.001). The occlusion/rest count ratio was lower, 61 +/- 6%, in patients with ST-segment elevation (n = 23) versus 74 +/- 9% in patients without ST-segment elevation (n = 7) (p < 0.0001).

CONCLUSIONS

Using 99mTc-sestamibi SPECT imaging during brief episodes of coronary occlusion, the severity of regional myocardial hypoperfusion was reduced by the presence of recruitable collaterals in a selected patient population with proximal LAD stenoses. Our results demonstrate a protective effect of recruitable collaterals on myocardial perfusion during temporary coronary occlusion.

Effect of pre-reperfusion residual flow on recovery from myocardial stunning: a myocardial contrast echocardiography study

BACKGROUND

Myocardial contrast echocardiography (MCE) may be used to assess coronary microvasculature in patients with myocardial infarction. Myocardial contrast echocardiography-no reflow suggests poor functional outcome; however, MCE with reflow does not necessarily indicate good myocardial salvage or sufficient functional recovery from myocardial stunning. In this study, MCE was performed to assess the effect of pre-reperfusion residual flow (PRF) on the recovery from myocardial stunning.

METHODS AND RESULTS

The size of the occluded bed, an area supplied with an infarct-related artery, was determined by comparing pre- and post-reperfusion MCE images in 40 patients with first acute myocardial infarction. Myocardial contrast echocardiography-no reflow was observed after reperfusion in 8 patients. Significant PRF was not recognizable in any of the 8 patients. The other patients with MCE reflow were subdivided into 2 groups on the basis of the ratio of the area perfused by PRF to that of the occluded bed: 14 patients with the ratio of more than 10% (PRF[+]), and the other 18 patients (PRF[-]). The wall motion score (0, normal to 4, dyskinetic) was obtained in the convalescent stage.

RESULTS

(1) Wall motion of the infarct area after day 3 was better in patients with PRF than in patients without PRF. (2) Left ventricular functional improvement in the long term was remarkable in patients with good reflow and PRF(+), modest in patients with good reflow but PRF(-), and not detectable in patients with MCE-no reflow. No significant correlation was found between angiographic collateral grades and PRF.

CONCLUSIONS

The presence of residual flow within the infarct area before reperfusion results in not only good myocardial salvage but also rapid functional recovery from myocardial stunning.

Adenosine as an adjunct to thrombolytic therapy for acute myocardial infarction: results of a multicenter, randomized, placebo-controlled trial: the Acute Myocardial Infarction STudy of ADenosine (AMISTAD) trial

OBJECTIVES

The Acute Myocardial Infarction STudy of ADenosine (AMISTAD) trial was designed to test the hypothesis that adenosine as an adjunct to thrombolysis would reduce myocardial infarct size.

BACKGROUND

Reperfusion therapy for acute myocardial infarction (MI) has been shown to reduce mortality, but reperfusion itself also may have deleterious effects.

METHODS

The AMISTAD trial was a prospective, open-label trial of thrombolysis with randomization to adenosine or placebo in 236 patients within 6 h of infarction onset. The primary end point was infarct size as determined by Tc-99 m sestamibi single-photon emission computed tomography (SPECT) imaging 6+/-1 days after enrollment based on multivariable regression modeling to adjust for covariates. Secondary end points were myocardial salvage index and a composite of in-hospital clinical outcomes (death, reinfarction, shock, congestive heart failure or stroke).

RESULTS

In all, 236 patients were enrolled. Final infarct size was assessed in 197 (83%) patients. There was a 33% relative reduction in infarct size (p = 0.03) with adenosine. There was a 67% relative reduction in infarct size in patients with anterior infarction (15% in the adenosine group vs. 45.5% in the placebo group) but no reduction in patients with infarcts located elsewhere (11.5% for both groups). Patients randomized to adenosine tended to reach the composite clinical end point more often than those assigned to placebo (22% vs. 16%; odds ratio, 1.43; 95% confidence interval, 0.71 to 2.89).

CONCLUSIONS

Many agents thought to attenuate reperfusion injury have been unsuccessful in clinical investigation. In this study, adenosine resulted in a significant reduction in infarct size. These data support the need for a large clinical outcome trial.

Spontaneous late improvement of myocardial viability in the chronic infarct zone is possible, depending on persistent TIMI 3 flow and a low grade stenosis of the infarct artery

OBJECTIVE

In the chronic phase of myocardial infarction, the relation between myocardial recovery and infarct related artery status remains unclear. The spontaneous changes in rest-redistribution thallium defect size were prospectively studied over six months in 52 patients with chronic Q wave myocardial infarction.

DESIGN

Changes in rest thallium defect size, thallium uptake in the infarct area, and radionuclide left ventricular ejection fraction were compared to the quantitative coronary angiogram data. Two groups of patients were considered: patients with a percentage of stenosis below 100% (group 1, n = 31); and patients with an occluded artery (group 2, n = 21).

RESULTS

In the overall population, the mean (SD) defect size decreased from 28.2 (17.2)% to 24.9 (19.3)% of the whole myocardium (p = 0.01), while, in this area, the thallium uptake increased from 62.9 (13.7)% to 66. 9 (15.6)% (p < 0.001). At the time of inclusion, the defect size, thallium uptake, and ejection fraction were similar in both groups. In group 1 patients only, the reduction in defect size correlated with the improvement in ejection fraction (r = 0.41, p = 0.02) and was related to the percentage of coronary artery stenosis. TIMI 3 patients reduced the defect size while other patients increased this defect (-5.1 (7.0)% v +11.0 (14.4)%, p < 0.001). In contrast, no significant relations were found in group 2 patients.

CONCLUSION

Late spontaneous recovery in thallium defect can occur in patients with a patent infarct related artery, depending on the TIMI flow grade and a low grade stenosis of the infarct related artery, and is associated with functional improvement.

Prediction of short- and intermediate-term prognoses of patients with acute myocardial infarction using myocardial contrast echocardiography one day after recanalization

OBJECTIVES

This study sought to determine whether microvascular integrity in the risk area (RA) for myocardial infarction (MI) one day after recanalization predicts the outcome in patients with first acute MI.

BACKGROUND

Immediately after recanalization, microcirculation in the RA is modified by both hyperemic response and microvascular impairment.

METHODS

Fifty consecutive patients who underwent serial myocardial contrast echocardiography before and one day after recanalization (day 2) were studied. All patients had a completely occluded lesion in the left anterior descending coronary artery alone, and underwent successful reperfusion therapy. The relative size of the initial RA (RA ratio) and peak gray scale ratio (PGSR) within the RA on day 2 were determined. Patients were followed for a median of 22 months to evaluate clinical outcome.

RESULTS

On day 2, PGSR was a median of 0.46. Study patients were subdivided into two groups, group A of 24 patients with acceptable opacification (PGSR > 0.46 on day 2) and group B of 26 patients without it. Major cardiac events (cardiac death, nonfatal MI and repeat admission for congestive heart failure) were more frequently observed in group B (28% vs. 4%, Cox hazard ratio=8.5, p=0.05, 95% confidence interval [CI] 1.03 to 69.9). The median value of the RA ratio was 0.45. Patients (n=15) with RA ratio > 0.45 on day 1 and PGSR on day 2 < or = 0.46 exhibited a 10.7-fold relative risk for major cardiac events (p=0.005, 95% CI 2.06 to 55.8) and a 3.69-fold relative risk for composite cardiac events (major cardiac events and target lesion revascularizations) after the initial intervention (p=0.004, 95% CI 1.51 to 9.04).

CONCLUSIONS

The assessment of both the size of the initial RA and microvascular integrity on day 2 enables precise determination of the efficacy of reperfusion therapy and prediction of the short- and intermediate-term prognoses of patients with recanalized MI.

Prevalence of spontaneous reperfusion and associated myocardial salvage in patients with acute myocardial infarction

This study sought to determine the prevalence of spontaneous reperfusion of an infarct-related artery (IRA) and associated myocardial salvage in the absence of thrombolysis or angioplasty. Twenty-one patients with acute myocardial infarction received only heparin and aspirin. At a median of 18 hours after presentation, 12 patients (57%) had angiographic patency of the IRA. Technetium-99m sestamibi was injected acutely on presentation and again at hospital discharge. Acute and final perfusion defect sizes were measured. Their difference, myocardial salvage, was calculated along with salvage index (myocardial salvage/acute defect). Comparing patients with a patent versus occluded IRA, myocardium at risk was similar (16% +/- 12% vs 12% +/- 9% left ventricle, p = NS); however, myocardial salvage (9% +/- 9% vs -2% +/- 7% left ventricle, p = 0.01), and salvage index (0.62 +/- 0.37 vs 0.19 +/- 0.33, p = 0.01) were greater in patients with spontaneous reperfusion. Resolution of chest pain was greater in patients with a patent IRA (100% vs 55%, p = 0.003). Spontaneous reperfusion of the IRA occurs frequently in patients with acute myocardial infarction and is associated with significant myocardial salvage.

Noninvasive prediction of residual blood flow within the risk area during acute myocardial infarction: a multicenter validation study of patients undergoing direct coronary angioplasty

BACKGROUND

In a previous study from a single center, radionuclide measures of collateral flow with technetium 99m sestamibi have been shown to be significantly associated with angiographic residual (antegrade and collateral) flow and independent predictors of final infarct size in acute myocardial infarction. This study examined whether the previously described radionuclide measures of blood flow to the infarct zone were reproducible with different laboratories and imaging systems.

METHODS AND RESULTS

Residual flow to the infarct zone was assessed by both invasive and noninvasive methods in 77 patients with first-time myocardial infarction (32 anterior, 45 nonanterior). All patients underwent acute coronary angiography before any intervention within 8 hours of the onset of chest pain (4.0 +/- 1.5 hours; range 1.2 to 7.9 hours). 99mTc sestamibi was injected intravenously before reperfusion therapy, and tomographic imaging was performed 1 to 6 hours after injection. A central core laboratory processed the acquired images from three centers, each with a unique camera and computer system. Three previously published methods based on the severity of the acute perfusion defect were used to measure residual flow to the infarct zone (nadir, severity index, area). Antegrade (Thrombolysis in Myocardial Infarction flow) and collateral flow before direct angioplasty were blindly graded on a four-point scale (0 to 3) from the acute angiogram. The simple sum of the two grades was defined as the angiographic flow index, representing residual flow to the jeopardized zone. All three noninvasive measures of residual flow were highly associated with the angiographic flow index in a linear fashion: severity index (p = 0.0006), area (p = 0.003), and nadir (minimum/maximum counts; p = 0.004). This association was independent of the laboratory where the data were acquired.

CONCLUSIONS

Despite different laboratories and camera systems, radionuclide measures of residual flow were highly associated with the angiographic flow index before reperfusion therapy. These results suggest that these measures are applicable on a broader scale for the noninvasive determination of collateral and antegrade flow in acute myocardial infarction.

Significance of the Thrombolysis in Myocardial Infarction scoring system in assessing infarct-related artery reperfusion and mortality rates after acute myocardial infarction

Thrombolysis in Myocardial Infarction (TIMI) flow scores were originally devised as semiquantitative angiographic measures of coronary artery perfusion. Several studies have indicated an important relation between different TIMI flow grades at 90 minutes after thrombolysis and clinical outcome. To further evaluate this relation we conducted a metaanalysis of all angiographic, postinfarction trials that studied the relation between individual 90-minute TIMI flow grades and mortality rates. In 4687 pooled patients, the mortality rate was lowest in patients with TIMI grade 3 flow (3.7%) and significantly lower than those with TIMI 2 (6.6%, p = 0.0003; odds ratio 0.55; 95% confidence interval [CI] 0.4% to 0.76%) or TIMI 0/1 flow (9.2%, p < 0.0001; odds ratio 0.38; 95% CI 0.29% to 0.5%). The mortality rate difference between TIMI grade 2 and TIMI grade 0/1 patients was also significant (p = 0.02; odds ratio 0.7; 95% CI 0.51% to 0.94%). This study confirms the importance of achieving rapid and complete reperfusion after acute myocardial infarction with the best outcome associated with 90-minute TIMI 3 flow. Furthermore, it shows that although TIMI 2 flow (partial perfusion) is not equivalent to TIMI 3 flow, it nevertheless still confers a significant survival benefit compared with TIMI flow 0/1.

Incidence and importance of thrombolysis in myocardial infarction grade 3 flow after primary percutaneous transluminal coronary angioplasty for acute myocardial infarction

We analyzed angiographic flow and myocardial salvage in 180 patients who underwent primary percutaneous transluminal coronary angioplasty (PTCA) without antecedent thrombolytic therapy for acute myocardial infarction. Thrombolysis in Myocardial Infarction (TIMI) flow grade was analyzed visually before and after PTCA. All patients underwent paired baseline (before angioplasty) and predischarge quantitative tomographic perfusion imaging with technetium-99m (Tc-99m) sestamibi techniques for assessment of the initial area at risk and final infarct size. The myocardial salvage index was defined as the proportion of jeopardized myocardium that was salvaged. After primary PTCA, TIMI grade 3 flow was obtained in 163 patients (91%), TIMI grade 2 flow in 13 patients (7%), and TIMI grade 0 or 1 flow in 4 patients (2%). There was a significant association between TIMI flow and both infarct size and salvage index. Infarct size was significantly smaller in patients with TIMI grade 3 flow than in those with TIMI grade 2 flow (15 +/- 16% vs 29 +/- 21% of left ventricular mass, p = 0.007). The salvage index was 55 +/- 41% of the area at risk in the TIMI 3 group and 27 +/- 38% of the area at risk in the TIMI 2 group (p = 0.04). After primary PTCA, restoration of TIMI grade 3 flow was necessary for optimal myocardial salvage. TIMI grade 2 flow was associated with a larger final infarct size and a lower salvage index.