Prognostic value of myocardial viability detected by myocardial contrast echocardiography early after acute myocardial infarction.

OBJECTIVES: This study sought to determine whether residual myocardial viability determined by myocardial contrast echocardiography (MCE) after acute myocardial infarction (AMI) can predict hard cardiac events. BACKGROUND: Myocardial viability detected by MCE has been shown to predict recovery of left ventricular (LV) function in patients with AMI. However, to date no study has shown its value in predicting major adverse outcomes in AMI patients after thrombolysis. METHODS: Accordingly, 99 stable patients underwent low-power MCE at 7 +/- 2 days after AMI. Contrast defect index (CDI) was obtained by adding contrast scores (1 = homogenous; 2 = reduced; 3 = minimal/absent opacification) in all 16 LV segments divided by 16. At discharge, 65 (68%) patients had either undergone or were scheduled for revascularization independent of the MCE result. The patients were subsequently followed up for cardiac death and nonfatal AMI. RESULTS: Of the 99 patients, 95 were available for follow-up. Of these, 86 (87%) underwent thrombolysis. During the follow-up time of 46 +/- 16 months, there were 15 (16%) events (8 cardiac deaths and 7 nonfatal AMIs). Among the clinical, biochemical, electrocardiographic, echocardiographic, and coronary arteriographic markers of prognosis, the extent of residual myocardial viability was an independent predictor of cardiac death (p = 0.01) and cardiac death or AMI (p = 0.002). A CDI of < or = 1.86 and < or = 1.67 predicted survival and survival or absence of recurrent AMI in 99% and 95% of the patients, respectively. CONCLUSIONS: The extent of residual myocardial viability predicted by MCE is a powerful independent predictor of hard cardiac events in patients after AMI.     

Assessment of Myocardial Viability in Patients With Postischemic Left Ventricular Dysfunction: Role of Myocardial Contrast Echocardiography

The distinction between viable and nonviable dysfunctional left ventricular (LV) segments after acute myocardial infarction is very important, because revascularization increases survival only in patients with viable myocardial tissue. Recent studies have highlighted a mismatch between two highly specific investigations for viability assessment: dobutamine echocardiography, which measures inotropic reserve, and myocardial contrast echocardiography (MCE), which measures microvascular perfusion. Viability and functional reserve are not synonymous. Maintenance of microvascular perfusion, independently of functional reserve, attenuates left ventricular remodelling, reduces the risk of major cardiac events, and increases survival. MCE provides similar perfusion information as myocardial blush, but image quality is much higher. Quantitative analysis of digital data provides more accurate diagnostic MCE information than qualitative analysis of video signal intensity. In a recent study relating MCE findings to histologic data, MCE-derived quantitative data were closely correlated with microvascular density and capillary area, and inversely correlated with collagen content. One of the contrast agents routinely used for MCE is SonoVue, a second generation microbubble contrast agent, which is characterized by high response to ultrasound energy, ease of destruction at high energy, and strong harmonic signal at low energy. Recommendations for the assessment of postischemic LV dysfunction: routine use of MCE, followed by dobutamine echocardiography if perfusion is documented. If MCE is negative, revascularization is not indicated; if both tests are positive, revascularization is strongly recommended; if they are discordant, useful information can be obtained by assessing the extent of ²⁰¹T1 viability. (ECHOCARDIOGRAPHY, Volume 20, Supplement 1, 2003)     

Myocardial contrast echography. History, methodology and clinical applications

Recent studies have demonstrated the usefulness of myocardial contrast echocardiography (MCE) in studying myocardial perfusion. Several first and second generation contrast agent such as Levovist, Sonovue, Optison, Definity and Imagent are commercially available or close to be introduced into the market. Use of MCE allowed the clinical demonstration of no-reflow phenomenon in patients with acute myocardial infarction (AMI) after recanalization of the infarct related artery (IRA). Coronary angiography is unable to assess the microvascular damage as showed by the poor correlation between TIMI grading and perfusion score evaluated by MCE. Furthermore, the use of MCE is important to determine coronary stenosis, to identify microvascular damage during ischaemia-reperfusion and to evaluate the presence of collateral circulation in the area at risk. MCE seems to be the most effective technique for assessing microvascular integrity after reperfusion as compared to TIMI myocardial perfusion grade, nuclear myocardial perfusion imaging and magnetic resonance imaging. These techniques are expensive, invasive and not available in most of the hospitals. Furthermore, as compared to nuclear medicine and echo-dobutamine, MCE has greater specificity and higher accuracy in detecting coronary artery disease. Recent studies showed that not only primary percutaneous coronary intervention (PCI) but also rescue and delayed PCI reduced microvascular damage and that MCE play a key role in assessing myocardial salvage after reperfusion. The most exciting aspect of MCE is the independent role in predicting left ventricular (LV) remodelling and functional recovery. The extent on no-reflow is an important predictor of LV dysfunction and remodelling at follow-up. Several studies have demonstrated that the extent of infarct-zone viability is a powerful independent predictor of LV dilation. There is a close relationship between the extent of microvascular damage, the extension of necrosis, the site of AMI and LV remodelling. We demonstrated that MCE performed 24 hours after reperfusion, at 1 week and 6 months appears to provide important prognostic information. These data support the daily use of MCE in coronary care unit and could establish a strategy for clinical decision making in patients with AMI.     

Prognostic Value of Real Time Myocardial Contrast Echocardiography after Percutaneous Coronary Intervention

Real time myocardial contrast echocardiography (RTMCE) is a cost‐effective and simple method to quantify coronary flow reserve (CFR). We aimed to determine the value of RTMCE to predict cardiac events after percutaneous coronary intervention (PCI). We have studied myocardial blood volume (A), velocity (β), flow indexes (MBF, A × β), and vasodilator reserve (stress‐to‐rest ratios) in 36 patients with acute coronary syndrome (ACS) who underwent PCI. CFR (MBF at stress/MBF at rest) was calculated for each patient. Perfusion scores were used for visual interpretation by MCE and correlation with TIMI flow grade. In qualitative RTMCE assessment, post‐PCI visual perfusion scores were higher than pre‐PCI (Z = ?7.26, P < 0.01). Among 271 arteries with TIMI flow grade 3 post‐PCI, 72 (36%) did not reach visual perfusion score 1. The β‐ and A × β‐reserve of the abnormal segments supplied by obstructed arteries increased after PCI comparing to pre‐PCI values (P < 0.01). Patients with adverse cardiac events had significantly lower β‐ and lower A × β‐reserve than patients without adverse cardiac events. In the former group, the CFR was ≥ 1.5 both pre‐ and post‐PCI. CFR estimation by RTMCE can quantify myocardial perfusion in patients with ACS who underwent PCI. The parameters β‐reserve and CFR combined might predict cardiac events on the follow‐up.     

Myocardial contrast echocardiography in ST elevation myocardial infarction: ready for prime time?

Acute myocardial infarction (AMI) continues to be a significant public health problem in industrialized countries and an increasingly significant problem in developing countries. ST elevation myocardial infarctions (STEMI) constitute approximately 40% of all AMIs with approximately 670,000 cases yearly in the United States alone. The risk of further cardiac complications such as re-infarction, sudden death, and heart failure for those who survive AMI is substantial. Thus, early assessment and risk stratification during the acute phase of STEMI is important. Furthermore, it is essential to assess the efficacy early after any initial therapeutic intervention, not only to facilitate further management, but also to enable development of new treatment algorithms/approaches to further improve the outcome. The aim of reperfusion therapy in AMI is not only to rapidly restore epicardial coronary blood flow but also to restore perfusion at the microcirculatory level. Myocardial contrast echocardiography (MCE) which utilizes microbubbles can assess myocardial perfusion in real time. Its ability to assess myocardial perfusion and function in one examination allows it to ascertain the extent of myocardial reperfusion achieved in the risk area. Furthermore, in stable patients after AMI, MCE allows assessment of LV function, residual myocardial viability, and ischaemia which are all powerful prognostic markers of outcome. Its portability, rapid acquisition and interpretation of data, and the absence of radiation exposure make it an ideal bedside technique.     

The Terminal Part of the QT Interval (T peak to T end): A Predictor of Mortality after Acute Myocardial Infarction

Background : The terminal part of the QT interval (T peak to T end; Tp‐e)—an index for dispersion of cardiac repolarization—is often prolonged in patients experiencing malignant ventricular arrhythmias after acute myocardial infarction (AMI). We wanted to explore whether high Tp‐e might predict mortality or fatal arrhythmia post‐AMI. Methods: Tp‐e was measured prospectively in 1359/1384 (98.2%) consecutive patients with ST elevation (n = 525) or non‐ST elevation (n = 859) myocardial infarction (STEMI or NSTEMI) admitted for coronary angiography. Results : Tp‐e was significantly correlated with age, heart rate (HR), heart failure, LVEF, creatinine, three‐vessel disease, previous AMI and QRS and QT duration. During a mean follow‐up of 1.3 years (range 0.4–2.3),109 patients (7.9%) died; 25, 45, and 39 from cardiac arrhythmia, nonarrhythmic cardiac causes and other causes, respectively. Long Tp‐e was strongly associated with increased risk of death, and Tp‐e remained a significant predictor of death in multivariable Cox analyses (RR 1.5, 95% CI[1.3–1.7]). HR‐corrected Tp‐e (cTp‐e) was the strongest predictor of death (RR 1.6 [1.4–1.9]). Tp‐e and cTp‐e were particularly strong predictors of fatal cardiac arrhythmia (RR 1.6 [1.2–2.1] and RR 1.8 [1.4–2.4]). Findings were similar in STEMI and NSTEMI. When comparing two methods for measuring Tp‐e, one including the tail of the T wave and one not, the former had markedly higher predictive power (P < 0.001). Conclusion : Tp‐e, and in particular cTp‐e, were strong predictors of mortality during the first year post‐AMI, and should be further evaluated as prognostic factors additional to established post‐AMI risk factors.     

Coronary flow reserve is reflective of myocardial perfusion status in acute anterior myocardial infarction.

Our objective was to determine whether coronary vasodilatory reserve (CVR) correlates with the perfusion state of infarct zone in early recovery phase of acute anterior myocardial infarction (AMI). We studied 14 patients (11 males; mean age, 46 years) who had AMI and 6 control subjects who had chest pain but normal coronary angiograms. All patients underwent successful percutaneous revascularization of left anterior descending (LAD) coronary artery. Coronary flow velocity was measured using intracoronary (IC) Doppler at baseline and following IC injection of 18 microg of adenosine. Myocardial perfusion was evaluated by myocardial contrast echocardiography (MCE). CVR was higher in patients without a perfusion defect on MCE than in those with (2.48 +/- 0.21 vs. 1.66 +/- 0.13, P = 0.001). Subjects with a perfusion defect had a lower CVR than controls (1.66 +/- 0.13 vs.2.40 +/- 0.18, P < 0.05). CVR was > 2.0 in all subjects without a perfusion defect. There was a strong correlation between the magnitude of myocardial opacification in the LAD territory and CVR (r = 0.80, P < 0.01). Increase in peak diastolic flow velocity after adenosine infusion, but not systolic flow velocity, correlated with myocardial opacification index (r = 0.63, P = 0.016). CVR of infarct-related artery correlated closely with the perfusion status of the myocardium in infarct zone and those with a CVR > 2.0 had normal myocardial perfusion. These data suggest that CVR may be used to determine the perfusion state of the myocardium in the infarct zone, which is a known predictor of myocardial viability. Cathet. Cardiovasc. Intervent. 51:281-286, 2000.     

NC100100, a new echo contrast agent for the assessment of myocardial perfusion--safety and comparison with technetium-99m sestamibi single-photon emission computed tomography in a randomized multicenter study

BACKGROUND AND HYPOTHESIS: Myocardial contrast echocardiography using second-generation agents has been proposed to study myocardial perfusion. A placebo-controlled, multicenter trial was conducted to evaluate the safety, optimal dose, and imaging mode for NC100100, a novel intravenous second-generation echo contrast agent, and to compare this technique with technetium-99m sestamibi (MIBI) single-photon emission computed tomography (SPECT). METHODS: In a placebo-controlled, multicenter trial, 203 patients with myocardial infarction > 5 days and < 1 year previously underwent rest SPECT and MCE. Fundamental and harmonic imaging modes combined with continuous and electrocardiogram-- (ECG) triggered intermittent imaging were used. Six dose groups (0.030, 0.100, and 0.300 microliter particles/kg body weight for fundamental imaging; and 0.006, 0.030, and 0.150 microliter particles/kg body weight for harmonic imaging) were tested. A saline group was also included. Safety was followed for 72 h after contrast injection. Myocardial perfusion by MCE was compared with myocardial rest perfusion imaging using MIBI as a tracer. RESULTS: NC100100 was well tolerated. No serious adverse events or deaths occurred. No clinically relevant changes in vital signs, laboratory parameters, and ECG recordings were noted. There was no significant difference between adverse events in the NC100100 (25.7%) and in the placebo group (17.9%, p = 0.3). Intermittent harmonic imaging using the intermediate dose was superior to all other modalities, allowing the assessment of perfusion in 76% of all segments. Eighty segments (96%) with normal perfusion by SPECT imaging also showed myocardial perfusion with MCE. However, a substantial percentage of segments (61-80%) with perfusion defects by SPECT imaging also showed opacification by MCE. This resulted in an overall agreement of 66-81% and a high specificity (80-96%), but in low sensitivity (20-39%) of MCE for the detection of perfusion defects. CONCLUSION: NC100100 is safe in patients with myocardial infarction. Intermittent harmonic imaging with a dose of 0.03 microliter particles/kg body weight can be proposed as the best imaging protocol. Myocardial contrast echocardiography with NC 100100 provides perfusion information in approximately 76% of segments and results in myocardial opacification in the vast majority of segments with normal perfusion as assessed by SPECT. Although the discrepancies between MCE and SPECT with regard to the definition of perfusion defects requires further investigation, MCE with NC 100100 is a promising technique for the noninvasive assessment of myocardial perfusion.     

前列地尔对改善急性心肌梗死PCI术后微循环及患者预后的影响

目的:探讨前列地尔治疗急性心肌梗死经皮冠状动脉介入术(PCI)治疗后微循环障碍以及改善患者预后的临床效果。方法:将57例因ST段抬高型急性心肌梗死接受急诊PCI的患者随机分为2组,前列地尔组在术前30 min使用前列地尔注射液治疗,并在术后继续治疗7 d。通过检测校正的TIMI帧数计数(CTFC)、心肌声学造影(MCE)等多种方法评估心肌灌注,并观察患者在住院和随访期间心功能情况及主要心脏不良事件。结果:前列地尔组术后的TIMI 3级血流发生率明显高于对照组(P=0.038),术后CTFC值也较对照组明显升高(P0.001);在治疗6个月后前列地尔组的左室射血分数(LVEF)、舒张早期充盈最大速率(E峰)与心房收缩期最大充盈速率(A峰)的比值(E/A)、左室舒张末期内径(LVEDD)以及左室收缩末期内径(LVESD)均较治疗3 d后有明显改善(P均0.05),而室间隔厚度(IVST)以及左室后壁舒张末期厚度(LVPWD)则无明显变化;两组患者PCI术后48 h、术后7 d的MCE显示,前列地尔组的局部心肌血流量在术后7 d有显著升高(P0.05)。对照组在住院和随访期间发生6例严重心力衰竭以及1例死亡病例,前列地尔组在住院期间发生严重心力衰竭1例,在随访期间发生严重心力衰竭1例,无死亡病例,两组比较无统计学差异。结论:前列地尔可以有效地改善PCI术后的心脏血流灌注,减少无复流现象的发生,可能改善急性心肌梗死患者心功能及临床预后。     

Tissue-Type Plasminogen Activator Therapy Versus Primary Coronary Angioplasty: Impact on Myocardial Tissue Perfusion and Regional Function 1 Month After Uncomplicated Myocardial Infarction

Objectives. This study sought to compare the impact of primary coronary angioplasty and thrombolytic therapy for acute myocardial infarction (AMI) on 1-month infarct size and microvascular perfusion.Background. The effect of the reperfusion strategies of primary coronary angioplasty and thrombolytic therapy on microvascular integrity still remains to be determined.Methods. Sixty-two consecutive patients with a first AMI, undergoing intravenous tissue-type plasminogen activator (t-PA) therapy (32 patients, Group I) or primary angioplasty (30 patients, Group II), were studied. Only patients with 1-month Thrombolysis in Myocardial Infarction (TIMI) flow grade 2 or 3 were selected for the study. Patients in whom primary angioplasty was unsuccessful or those with clinical evidence of failed reperfusion were excluded. Microvascular perfusion was assessed at 1 month by intracoronary injection of sonicated microbubbles. Contrast score index (CSI) and wall motion score index (WMSI) were derived using qualitative methods.Results. At baseline there were no significant differences between groups for age, risk factors, time to hospital presentation, Killip class on admission, prevalence of multivessel disease or anterior infarct site, infarct area extension before reperfusion, peak creatine kinase levels and postinfarction treatment. Conversely, significant differences between groups were found at follow-up for percent residual infarct related-artery (IRA) stenosis (70 ± 12 vs 36 ± 14 [mean ± SD], p = 0.0001), CSI (1.02 ± 0.4 vs. 1.49 ± 0.5, p = 0.0003) and WMSI (1.67 ± 0.3 vs. 1.45 ± 0.3, p = 0.015). In particular, in the subset of patients with TIMI grade 3 flow, a perfusion defect occurred in one or more segments subtended by the IRA in 72% of Group I versus 31% of Group II patients (p < 0.00001) and in 27% of Group I versus 8% of Group II segments (p < 0.00001).Conclusions. The present study shows, in a highly selected cohort with successful IRA recanalization, that primary angioplasty is more effective than thrombolysis in preserving microvascular flow and preventing extension of myocardial damage at 1-month after AMI.     

Detection of functional recovery using low-dose dobutamine and myocardial contrast echocardiography after acute myocardial infarction treated with successful thrombolytic therapy

OBJECTIVE: We studied the value of low-dose dobutamine stress echocardiography (LDDE) and myocardial contrast echocardiography (MCE) in early prediction of left ventricular functional recovery (LVFR) after acute myocardial infarction (AMI) treated with successful thrombolysis. DESIGN: LDDE and MCE using second-harmonic intermittent imaging were performed in first week after AMI. LVFR was defined as an absolute > or =5% increase in ejection fraction, from early to 6 months of follow-up by Technetium-99m-Sestamibi single-photon emission computed tomography. PATIENTS: Out of 50 patients studied, 19 evolved with LVFR (group 1) and 31 without LVFR (group 2). Regional dysfunction was detected in 103 (37%) infarcted-related segments in group 1 and in 173 (63%) segments in group 2. RESULTS: Sensitivity, specificity, positive, and negative predictive values and accuracy for detecting LVFR by LDDE were 94.7% (18/19), 87.1% (27/31), 81.8% (18/22), 96.4% (27/28), and 90% (45/50), respectively, and by MCE were 94.7% (18/19), 51.6% (16/31), 54.5% (18/33), 94.1% (16/17), and 68% (34/50). In group 1, functional improvement was observed in 86.9% (53/61) of segments with contractile reserve by LDDE and in 65.8% (52/79) of segments with microvascular perfusion by MCE. In group 2, functional improvement was observed in 78.3% (18/23) of segments with contractile reserve by LDDE and in 25.5% (25/98) of segments with microvascular perfusion by MCE. All segments without perfusion by MCE evolved without functional recovery. CONCLUSION: LDDE was an accurate predictor of late left ventricular function recovery after AMI, while MCE was sensitive and has a high negative predictive value demonstrating that microvascular perfusion is essential for LVFR.     

Usefulness of myocardial contrast echocardiography using low-power continuous imaging early after acute myocardial infarction to predict late functional left ventricular recovery

Microvascular perfusion is a prerequisite for ensuring viability early after acute myocardial infarction (AMI). For adequate assessment of myocardial perfusion, both myocardial blood volume and velocity need to be evaluated. Due to its high frame rate, low-power continuous myocardial contrast echocardiography (MCE) can rapidly assess these parameters of myocardial perfusion. We hypothesized that the technique can accurately differentiate necrotic from viable myocardium after reperfusion therapy in AMI. Accordingly, 50 patients underwent low-power continuous MCE using intravenous Optison (Amersham Health, Amersham, Middlesex, United Kingdom) 7 to 10 days after AMI. Myocardial perfusion (contrast opacification assessed over 15 cardiac cycles after the destruction of microbubbles with high energy pulses) and wall thickening were assessed at baseline. Regional and global left ventricular (LV) function was reassessed after 12 weeks. Out of the 297 dysfunctional segments, MCE detected no contrast enhancement during 15 cardiac cycles in 172 segments, of which 160 (93%) failed to show improvement. MCE demonstrated contrast opacification during 15 cardiac cycles in 77 segments, of which 65 (84%) showed recovery of function. The greater the extent and intensity of contrast opacification, the better the LV function at 3 months (p <0.001, r = -0.91). Almost all patients (94%) with <20% perfusion in dysfunctional myocardium (assessing various cut-offs) failed to demonstrate an improvement in LV function. MCE and peak creatine kinase proved to be independent predictors of functional recovery (p <0.001). In conclusion, low-power continuous MCE is an accurate and rapid bedside technique to identify microvascular perfusion after AMI. This technique may be utilized to reliably predict late recovery of function in dysfunctional myocardium after AMI.     

Contrast echocardiography and acute coronary syndromes

Since microvascular perfusion parallels myocardial viability, myocardial contrast echocardiography (MCE) can provide informations regarding myocardial recovery after an acute myocardial infarction (AMI). Recent studies have demonstrated the role of MCE to evaluate the value of perfusion and function during rest and dobutamine stress echo in patients early after AMI in terms of risk stratification and management of these patients.     

Quantitative Myocardial Contrast Supine Bicycle Stress Echocardiography for Detection of Coronary Artery Disease

Background: If compared with two‐dimensional echocardiography (2DE), quantitative myocardial contrast echocardiography (MCE) improves detection of coronary artery disease (CAD) during pharmacological stress, but there is paucity of data regarding quantitative MCE performed during supine bicycle stress. Objectives: To determine the feasibility and accuracy of quantitative MCE and assess its incremental benefit over 2DE for detection of CAD during supine bicycle stress. Methods: Sixty‐one consecutive patients (47 males, 14 females, mean age 57 ± 12 years) with suspected CAD, who were scheduled for coronary angiography, underwent 2DE and MCE supine bicycle stress. The diagnosis of obstructive CAD (≥50% stenosis) was based on inducible wall‐motion and myocardial perfusion abnormalities. For quantitative myocardial perfusion analysis, A, β, and Aβ reserve were derived from myocardial contrast replenishment curves. Results: Quantitative coronary angiography revealed ≥50% stenosis in 41, ≥70% stenosis in 18, single vessel disease in 24, and multivessel disease in 17 patients. If compared with 2DE, quantitative MCE was more sensitive (71% vs. 93%; P < 0.05) and more accurate (74% vs. 89%; P < 0.05) to detect obstructive CAD. The sensitivity of 2DE and quantitative MCE was 61% and 91% (P < 0.05) in 50–69% stenosis, and 63% and 92% (P < 0.05) in single vessel disease. No difference in sensitivity between 2DE and quantitative MCE was found in subjects with ≥70% stenosis (83% vs. 94%, P = NS) and multivessel disease (82% vs. 94%, P = NS). Conclusions: Quantitative MCE enhances sensitivity and accuracy of supine bicycle stress 2DE for detection of obstructive CAD, and this incremental benefit is especially present in less severe disease.     

Myocardial perfusion assessed by contrast echocardiography correlates with angiographic perfusion parameters in patients with a first acute myocardial infarction successfully treated with angioplasty

BACKGROUND:

Angiographic flow in an epicardial artery does not define perfusion at the microvascular level.

AIM:

To compare myocardial contrast echocardiography (MCE) with angiographic methods of assessing microvascular reperfusion in patients with acute myocardial infarction (AMI).

METHODS:

One hundred consecutive patients with a first ST segment elevation myocardial infarction and single-vessel disease were successfully treated with primary percutaneous coronary intervention. Regional contrast score index (RCSI), corrected Thrombolysis In Myocardial Infarction (TIMI) frame count (cTFC), TIMI myocardial perfusion grade (TMPG) and myocardial blush grade were evaluated.

RESULTS:

Among 717 asynergic segments on MCE, 168 revealed a lack of perfusion. TMPG and cTFC correlated significantly with RCSI (P=0.031 and P=0.027, respectively). Myocardial blush grade did not correlate with RCSI (P=0.067). Patients with anterior AMI had significantly more segments with a perfusion defect on MCE than patients with inferior AMI (P=0.0001).

CONCLUSIONS:

MCE results correlate with angiographic methods of perfusion assessment such as TMPG and cTFC. Anterior AMI is associated with a greater extent of perfusion defect. MCE results correlate also with recovery of systolic left ventricular function and clinical outcome at six month follow-up.     

Association between pulse pressure at discharge and clinical outcomes in patients with acute myocardial infarction: From the KAMIR‐Korean‐NIH registry

Pulse pressure (PP) is affected by arterial stiffness and is a predictor of cardiovascular events. However, value and utility of PP assessment in patients with acute myocardial infarction (AMI) remain less clear. We aimed to evaluate the association between PP and cardiovascular events in surviving patients with AMI at discharge. A total of 11 944 surviving patients with AMI at discharge from a Korean nationwide registry were included. Blood pressure was checked just before discharge. Noncardiac death and major adverse cardiovascular events (MACEs) including cardiac death, AMI, and stroke after discharge were analyzed. The median follow‐up duration was 368 (IQR 339, 388) days. The rate of MACEs and cardiac death was higher in groups with the lowest PP (PP < 20 mm Hg) and highest PP (PP ≥ 71 mm Hg) and lowest in the group with PP of 31‐40 mm Hg. With PP of 31‐40 mm Hg as reference, univariate analysis showed a U‐shaped association between the risk of MACEs (PP ≤ 20 mm Hg: hazard ratio [HR] 2.3; PP ≥ 71 mm Hg: HR 2.7) or cardiac death (PP ≤ 20 mm Hg: HR 2.6; PP ≥ 71 mm Hg: HR 3.1) and PP. In multivariate analysis, the curve changed from being U‐shaped to J‐shaped, and HR for PP ≥ 71 mm Hg (1.2 for MACEs and 1.4 cardiac death) decreased and HR for PP < 20 (2.1 for MACEs and 2.4 for cardiac death) did not significantly decrease after adjustment for cardiovascular risk factors. Our findings indicate that PP is a strong independent prognostic factor of MACEs and cardiac death in surviving patients with AMI. Low PP is a more significant independent predictor of MACEs and cardiac death than high PP in surviving patients after AMI.     

Pro-Substance P for Evaluation of Risk in Acute Myocardial Infarction

Background

Pro-substance P (ProSP) is a stable surrogate marker for labile substance P, which has pro-inflammatory effects, increases platelet aggregation and clot strength, and reduces fibrinolysis.

Objectives

This study assessed whether ProSP was associated with poor prognosis after acute myocardial infarction (AMI) to identify novel pathophysiological mechanisms.

Methods

ProSP was measured in 1,148 AMI patients (825 men, mean age 66.2 ± 12.8 years). Endpoints were major adverse cardiac events (composite of death, reinfarction, and heart failure [HF] hospitalization), death/reinfarction, and death/HF. GRACE (Global Registry of Acute Coronary Events) scores were compared with ProSP for death and/or reinfarction at 6 months.

Results

During 2-year follow-up, there were 140 deaths, 112 HF hospitalizations, and 149 re-AMI. ProSP levels were highest on the first 2 days after admission and related to estimated glomerular filtration rate, age, history of diabetes, ischemic heart disease or hypertension, Killip class, left ventricular wall motion index, and sex. Multivariate Cox regression models showed ProSP level was a predictor of major adverse events (hazard ratio [HR]: 1.30; 95% confidence interval [CI]: 1.10 to 1.54; p < 0.002), death and/or AMI (HR: 1.42; 95% CI: 1.20 to 1.68; p < 0.0005), death and/or HF (HR: 1.38; 95% CI: 1.14 to 1.67; p < 0.001). ProSP levels with GRACE scores were independent predictors of 6-month death and/or reinfarction (p < 0.0005 for both). ProSP-adjusted GRACE scores reclassified patients significantly (overall category-free net reclassification improvement of 31.6 (95% CI: 14.3 to 49.0; p < 0.0005) mainly by down-classifying those without endpoints.

Conclusions

ProSP levels post-AMI are prognostic for death, recurrent AMI, or HF, and they improve risk prediction of GRACE scores, predominantly by down-classifying risk in those without events.     

Predictive value of markers of myocardial reperfusion in acute myocardial infarction for follow-up left ventricular function

This study evaluated recently suggested invasive and noninvasive parameters of myocardial reperfusion after acute myocardial infarction (AMI), assessing their predictive value for left ventricular function 4 weeks after AMI and reperfusion defined by myocardial contrast echocardiography (MCE). In 38 patients, angiographic myocardial blush grade, corrected Thrombolysis In Myocardial Infarction frame count, ST-segment elevation index, and coronary flow reserve (n = 25) were determined immediately after primary percutaneous transluminal coronary angioplasty (PTCA) for first AMI, and intravenous MCE was determined before, and at 1 and 24 hours after PTCA to evaluate myocardial reperfusion. Results were related to global wall motion index (GWMI) at 4 weeks. MCE 1 hour after PTCA showed good correlation with GWMI at 4 weeks (r = 0.684, p <0.001) and was in an analysis of variance the best parameter to predict GWMI 4 weeks after AMI. The ST-segment elevation index was close in its predictive value. Considering only invasive parameters of reperfusion myocardial blush grade was the best predictor of GWMI at 4 weeks (R² = 0.3107, p <0.001). A MCE perfusion defect size at 24 hours of ≥50% of the MCE perfusion defect size before PTCA was used to define myocardial nonreperfusion. In a multivariate analysis, low myocardial blush grade class was the best predictor of nonreperfusion defined by MCE. Thus, intravenous MCE allows better prediction of left ventricular function 4 weeks after AMI than other evaluated parameters of myocardial reperfusion. Myocardial blush grade is the best predictor of nonreperfusion defined by MCE and is the invasive parameter with the greatest predictive value for left ventricular function after AMI. Coronary flow parameters are less predictive.     

慢性完全闭塞病变对接受急诊介入治疗的急性心肌梗死患者远期预后的影响

目的:分析慢性完全闭塞(CTO)病变对接受急诊介入治疗的急性心肌梗死(AMI)患者远期预后的影响。方法:分析自2013年1月至2014年9月间纳入中国急性心肌梗死(CAMI)注册登记研究的接受急诊介入治疗的14176例AMI患者,根据冠状动脉造影的结果,将患者分为AMI合并CTO病变组(n=1235)和AMI不合并CTO病变组(n=12941)。随访2年,比较两组的临床预后,主要研究终点为死亡率,次要研究终点为包括心原性死亡、脑卒中、心力衰竭再入院、再次血运重建等的主要不良心血管事件。结果:合并CTO病变的AMI患者占8.7%(1235/14176)。随访2年,AMI合并CTO病变组的患者全因死亡率(9.9%vs.5.4%)和心原性死亡率(5.0%vs.2.6%)明显高于AMI不合并CTO病变组患者(P均<0.01)。单因素分析显示,CTO病变增加AMI患者死亡(HR=1.44,95%CI:1.02~2.03,P=0.04)和再次血运重建(HR=2.14,95%CI:1.55~2.96,P<0.01)风险。多因素回归分析显示,高龄(HR=1.07,95%CI:1.05~1.09)和就诊时存在心力衰竭(HR=2.05,95%CI:1.36~3.09)与患者2年死亡的不良预后明显相关(P均<0.01),而CTO病变不是2年死亡的独立危险因素(HR=1.33,95%CI:0.93~1.90,P=0.11)。结论:合并CTO病变的AMI患者的远期死亡率和心原性死亡率明显高于不合并CTO病变的患者。高龄和就诊时存在心力衰竭是远期死亡的独立危险因素,而CTO病变并不是远期死亡的独立危险因素。     

Serial evaluation of perfusion defects in patients with a first acute myocardial infarction referred for primary PTCA using intravenous myocardial contrast echocardiography.

AIMS: To investigate whether myocardial contrast echocardiography using Sonazoid could be used for the serial evaluation of the presence and extent of myocardial perfusion defects in patients with a first acute myocardial infarction treated with primary PTCA, and specifically, (1) to evaluate safety and efficacy of myocardial contrast echocardiography to detect TIMI flow grade 0--2, (2) to evaluate the success of reperfusion and (3) to predict left ventricular recovery after 4 weeks follow-up. METHODS AND RESULTS: Fifty-nine patients underwent serial myocardial contrast echocardiography, immediately before primary PTCA (MCE1), 1 h (MCE2) and 12--24 h after PTCA (MCE3). A perfusion defect was observed in 21 of 24 patients (88%) with anterior acute myocardial infarction. All but one had TIMI flow grade 0--2 prior to PTCA. Nine of 31 patients (29%) with inferior acute myocardial infarction showed a perfusion defect and all had TIMI flow grade 0-2 prior to PTCA. Restoration of TIMI flow grade 3 was achieved in 73% of the patients by primary PTCA. A reduction in size of the initial perfusion defect of at least one segment (16 segment model) or no defect vs persistent defect in patients with anterior acute myocardial infarction was associated with improved global left ventricular function at 4 weeks; mean global wall motion score index 1.29+/-0.21 vs 1.66+/-0.31 (P=0.009). Multiple regression analysis in patients with an anterior acute myocardial infarction revealed that the extent of the perfusion defect at MCE3 was a significant (P=0.0005) independent predictor for left ventricular recovery at 4 weeks follow-up. The only other independent predictor was TIMI flow grade 3 post PTCA (P=0.007). CONCLUSION: Intravenous myocardial contrast echocardiography immediately prior to primary PTCA seems safe and is capable of detecting the presence of a perfusion defect and its subsequent dynamic changes, particularly in patients with a first anterior acute myocardial infarction. A significant reduction in size of the initial perfusion defect using serial myocardial contrast echocardiography predicts functional recovery after 4 weeks and these findings underscore the potential diagnostic value of intravenous myocardial contrast echocardiography.