Usefulness of 500-m walk electrocardiogram test on clinical outcomes in patients with ST-segment elevation myocardial infarction

Impact of Excessive Increase in Systolic Blood Pressure after Exercise on Clinical Outcomes in Patients with ST-Segment Elevation Myocardial Infarction

OBJECTIVE

Although the clinical outcomes for patients with ST-elevation myocardial infarction (STEMI) have improved significantly, some patients still experience poor clinical outcomes. The available risk classifications focus on the short-term outcomes, and it remains important to find high-risk features among patients with STEMI. In Japan, the 200 m walk electrocardiogram (ECG) test is widely performed before discharge. The purpose of this study was to investigate the association between the excessive increase in systolic blood pressure (SBP) following a 200 m walk and the long-term clinical outcomes in patients with STEMI.

METHODS

We included 680 patients with STEMI and divided those into an excessive increase in SBP group (n = 144) and a non-excessive increase in SBP group (n = 536) according to the SBP increase after a 200 m walk ECG test. We defined an excessive increase in SBP as SBP ≥ 20 mmHg either just after or 3 min after a 200 m walk ECG test. The primary endpoint consisted of major cardiovascular events (MACE), defined as the composite of all-cause death, non-fatal myocardial infarction, readmission for heart failure, and ischemia-driven target vessel revascularization.

RESULTS

The median follow-up duration was 831 days. MACE was more frequently observed in the excessive increase in SBP group (24.3%) than in the non-excessive increase in SBP group (15.1%). Multivariate Cox hazard analysis revealed that the excessive increase in SBP was significantly associated with MACE (HR 1.509, 95% CI: 1.005-2.267, p = 0.047) after controlling for multiple confounding factors.

CONCLUSION

An excessive increase in SBP after the 200 m walk ECG test was significantly associated with MACE in patients with STEMI. The 200 m walk ECG test is simple and low-cost, but may help to identify high-risk patients with STEMI.

Factors associated with intensive care unit delirium in patients with acute myocardial infarction

Some patients admitted to intensive care units (ICU) would develop delirium, which is associated with poor prognosis. The purpose of this retrospective study was to identify factors associated with ICU delirium in patients with acute myocardial infarction (AMI). We included 753 AMI and divided those into the ICU-delirium group (n = 110) and the non-ICU-delirium group (n = 643) according to the presence of ICU delirium. The ICU delirium was evaluated by confusion assessment method for the intensive care unit. Patient characteristics and clinical outcomes were compared between the 2 groups, and factors associated with ICU delirium were sought by multivariate analysis. The prevalence of female sex was significantly higher in the ICU-delirium group (43.6%) than in the non-ICU-delirium group (20.2%) (p < 0.001). The incidence of in-hospital death was significantly higher in the ICU-delirium group (17.3%) than in the non-ICU-delirium group (0.5%) (p < 0.001). The multivariate logistic regression analysis revealed that age [every 10 years increase: odds ratio (OR) 1.439, 95% confidence interval (CI) 1.127-1.837, p = 0.004], female sex (OR 2.237, 95%CI 1.300-3.849, p = 0.004), triple vessel disease (OR 2.317, 95%CI 1.365-3.932, p = 0.002), body mass index < 18.5 kg/m² (OR 2.910, 95%CI 1.410-6.008, p = 0.004), use of mechanical support (OR 2.812, 95%CI 1.500-5.270, p = 0.001), respiratory failure (OR 5.342, 95%CI 3.080-9.265, p < 0.001), and use of continuous renal replacement therapy (OR 5.901, 95%CI 2.520-13.819, p < 0.001) were significantly associated with ICU delirium. In conclusion, ICU delirium was associated with in-hospital death. Older age, female sex, triple vessel disease, leanness, use of mechanical support, respiratory failure, and continuous renal replacement therapy were significantly associated with the occurrence of ICU delirium.

Comparison of in-hospital outcomes of acute myocardial infarction between patients with cardiogenic shock and with cardiac arrest

In-hospital mortality of acute myocardial infarction (AMI) complicated with cardiogenic shock (CS) remains high. Also, in-hospital mortality of AMI complicated with cardiac arrest (CA) has been reported to be highest among any AMI. However, there were few reports that compared in-hospital mortality directly between AMI complicated with CS and complicated with CA. The purpose of this study was to compare in-hospital outcomes between AMI complicated with CS and complicated with CA. We retrospectively included 195 AMI patients complicated by CS or CA, and divided those into the CA group (n = 109) and the CS group (n = 86). We also subdivided the CA group into CA with persistent CS (n = 83) and CA without persistent CS (n = 26). One-third of the study population died during the index admission. In-hospital death was more frequently observed in the CA group (45.0%) than in the CS group (20.9%) (p < 0.001). In-hospital mortality was highest in the CA with persistent CS group (68.7%), followed by the CS group (20.9%), and least in the CA without persistent CS group (11.5%) (p < 0.001). Favorable neurological function was more frequently observed in the CA without persistent CS group (76.9%) and the CS group (74.4%) than in the CA with persistent CS group (27.7%) (p < 0.001). In conclusion, in-hospital mortality was higher in AMI patients with CA than in those with CS. However, when we divided AMI patients with CA into those with and without persistent CS, in-hospital mortality was lowest in CA without persistent CS, followed by CS, and highest in CA with persistent CS.

Comparison of Long-Term Clinical Outcomes in Patients Stratified by a Novel Acute Myocardial Infarction Risk Stratification (nARS) System

BACKGROUND

As severity of acute myocardial infarction (AMI) varies widely, several risk stratifications for AMI have been reported. We have introduced a novel AMI risk stratification system linked to a rehabilitation program (novel AMI risk stratification; nARS), which stratified AMI patients into low (L)-, intermediate (I)-, and high (H)-risk groups. The purpose of this retrospective study was to compare the long-term clinical outcomes in patients with AMI among L-, I-, H-risk groups.

METHODS AND RESULTS

This study included 773 AMI patients, and assigned them into the L-risk group (n=332), the I-risk group (n=164), and the H-risk group (n=277). The primary endpoint was major cardiovascular events (MACE), defined as the composite of all-cause death, readmission for heart failure, non-fatal myocardial infarction, and target vessel revascularization after the discharge of index admission. The median follow-up duration was 686 days. MACE was most frequently observed in the H-risk group (39.4%), followed by the I-risk group (23.2%), and least in the L-risk group (19.9%) (P<0.001). The multivariate Cox hazard analysis revealed that the H-risk was significantly associated with MACE (HR 2.166, 95% CI 1.543-3.041, P<0.001) after controlling for multiple confounding factors.

CONCLUSIONS

H-risk according to nARS was significantly associated with long-term adverse events after hospital discharge for patients with AMI. These results support the validity of nARS as a risk marker for long-term outcomes.

Association of collateral flow with clinical outcomes in patients with acute myocardial infarction

Coronary collateral flow is an important prognostic marker in percutaneous coronary intervention (PCI) for chronic total occlusion. However, the role of collateral flow to the culprit lesion of acute myocardial infarction (AMI) has not been fully established yet. The purpose of this retrospective study was to examine the association between collateral flow and long-term clinical outcomes in patients with AMI. We included 937 patients with AMI, and divided those into the no-collateral group (n = 704) and the collateral group (n = 233) according to the presence or absence of collateral flow to the culprit lesion of AMI. The primary endpoint was the incidence of major adverse cardiac events (MACE), which was defined as a composite of all-cause death, non-fatal MI, re-admission for heart failure, and ischemia driven target vessel revascularization. The median follow-up duration was 473 days (Q1: 184 days- Q3: 1027 days), and a total of 263 MACE was observed during the study period. The incidence of MACE was significantly greater in the no-collateral group than in the collateral group (29.8% vs. 22.3%, p = 0.027). In the multivariate COX hazard model, the presence of collateral flow was inversely associated with MACE (HR 0.636, 95% CI 0.461-0.878, p = 0.006) after controlling multiple confounding factors. In conclusion, the presence of collateral flow to the culprit lesion of AMI was inversely associated with long-term adverse outcomes. Careful observation of collateral flow may be important in emergent coronary angiography to stratify a high-risk group among various patients with AMI.

Impact of accelerated washout of Technetium-99m-sestamibi on exercise tolerance in patients with acute coronary syndrome: single-center experience

Technetium-99m-sestamibi (^99mTc-sestamibi) single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) in patients with acute coronary syndrome (ACS) could be used to assess area-at-risks, as well as myocardial infarct or saved sizes. In patients with ACS, accelerated washout of ^99mTc-sestamibi during early and delayed imaging in the acute phase may suggest mitochondrial dysfunction in the injured but salvaged myocardium. However, the link between ^99mTc-sestamibi accelerated washout and exercise tolerance is unknown. The purpose of this study was to investigate a possible association between ^99mTc-sestamibi accelerated washout and exercise tolerance in acute ACS patients as they progressed into the chronic phase. One hundred and sixty-five patients with ACS who underwent ^99mTc-sestamibi SPECT MPI during the acute phase were recruited. On this basis, we calculated the total perfusion deficits (TPDs) for early (1 h after tracer injection) and delayed (4 h after tracer injection) images using automated quantification software. We then subtracted the early TPDs from the delayed TPDs to calculate the ΔTPD. We conducted a cardiopulmonary exercise test in acute and chronic phases. We divided two groups according to the median ΔTPD (the ΔTPD ≥ 4 group and the ΔTPD < 4 group) and compared anaerobic threshold (AT; ml/kg/min) between the groups. For anaerobic threshold (AT) improvement in data analysis, we employed multivariate logistic regression analysis. A total of 101 ST-segment elevation myocardial infarctions, 36 non-ST-elevation myocardial infarctions, and 28 unstable angina pectoris events were reported as ACS. From acute phase (10.8 ± 4.2 ml/kg/min) to chronic phase (11.9 ± 2.3 ml/kg/min), the AT in the ΔTPD ≥ 4 group was significantly increased (p < 0.0001). This trend was also seen in the ΔTPD < 4 group from acute (11.4 ± 1.8 ml/kg/min) to chronic phase (12.1 ± 2.2 ml/kg/min, p = 0.015). AT was lower in the ΔTPD ≥ 4 group in the acute phase (p = 0.027), but there was no difference in AT between the two groups in the chronic phase (p = 0.60). ΔTPD and the absence of diabetes were both independent predictors of AT improvement in multivariate logistic regression analysis. Receiver-operating characteristic curve analysis determined that ΔTPD = 6 was the best cut-off value, with 60.0% sensitivity and 71.4% specificity, respectively. The accelerated washout of ^99mTc-sestamibi in patients with ACS during the acute phase could help to predict improvement in exercise tolerance in the chronic phase.