Can we improve length of hospitalization in ST elevation myocardial infarction patients treated with primary percutaneous coronary intervention?

BACKGROUND:

Patients with ST elevation myocardial infarction have traditionally been hospitalized for five to seven days to monitor for serious complications such as heart failure, arrhythmias, reinfarction and death. The Zwolle primary percutaneous coronary intervention (PCI) index is an externally validated risk score that has been used to identify low-risk primary PCI patients who can safely be discharged from the hospital within 48 h to 72 h.

METHODS:

The Zwolle score was retrospectively applied to all ST elevation myocardial infarction patients treated with primary PCI between April 2004 and February 2006 at a large Canadian teaching hospital. The goal was to characterize length of stay (LOS) in low-risk patients and to identify variables that correlate with patients who were hospitalized longer than expected.

RESULTS:

Data were collected on 255 patients. The mean LOS was 7.2±7.7 days (median 5.0 days [interquartile range 3.5 days]). A total of 179 patients (70%) had a Zwolle score of 3 or lower, identifying them as low risk. There was one death in the low-risk group (0.6% 30-day mortality) and 15 deaths in the higher-risk group (19.7% 30-day mortality), validating the Zwolle score in the population. A contraindication to early discharge was identified in 34 of the low-risk patients. Among the 144 remaining low-risk patients, the mean LOS was 5.1±3.3 days (median 4.0 days [interquartile range 3.0 days]). Only 8% were discharged within 48 h and only 28% within 72 h. It was determined that fewer patients were discharged on weekends and Wednesdays (when medical residents were away for teaching) than on other weekdays. LOS was longer among patients who were discharged on warfarin (7.6 days versus 4.6 days, P=0.006), and among patients who were transferred back to their presenting hospital rather than being discharged directly from the hospital where PCI was performed (5.6 days versus 4.0 days, P<0.001).

CONCLUSIONS:

Seventy-two per cent of low-risk primary PCI patients were hospitalized longer than 72 h. The following three factors were identified as correlating with prolonged LOS in this population: fewer discharges on days when there was less resident staffing; the use of warfarin at discharge; and transfer of patients back to their presenting hospital rather than discharging them directly from the PCI-performing hospital. A programmed approach to the identification and early discharge of low-risk patients could have significant cost savings and should be investigated prospectively.     

Primary percutaneous coronary intervention for every patient with ST-segment elevation myocardial infarction: what stands in the way?

According to data from randomized, controlled trials, primary percutaneous coronary intervention (PCI) is the treatment of choice for ST-segment elevation myocardial infarction (MI). In these trials, 1 life was saved and 2 other life-threatening complications, including stroke and reinfarction, were prevented for every 50 patients with ST-segment elevation MI treated with primary PCI rather than thrombolytic therapy. Only 1 major bleeding episode occurred. How can these superior results be realized outside the context of randomized trials? We anticipate 4 obstacles to instituting primary PCI as the universal treatment of ST-segment elevation MI: 1) lack of timely availability, 2) technical expertise of center and operator, 3) the need to address patient subgroups that are not studied in randomized trials, and 4) comparisons of primary PCI to newer pharmacologic regimens. We propose 3 strategies to increase the availability of this procedure: 1) perform primary PCI in qualified community hospitals without surgical back-up; 2) transfer patients from community hospitals without primary PCI capability to hospitals with primary PCI capability; and 3) develop a universal system in which ambulances directly transfer patients to a regional primary PCI center, not necessarily to the closest hospital, similar to the system used for trauma patients. We contend that, in light of the superior clinical outcomes seen with primary PCI for treating ST-segment elevation MI, this procedure should be available to all patients with ST-segment elevation MI and efforts should be made to institute these measures.     

Does glucose level at hospital discharge predict one-year mortality in patients with diabetes mellitus treated with percutaneous coronary intervention for ST-segment elevation myocardial infarction?

BACKGROUND: It has been shown that diabetes mellitus (DM) is an independent prognostic factor in patients with myocardial infarction (MI). In addition to that fact the prognostic significance of blood glucose (BG) abnormalities in the acute phase of MI has also been suggested. Recently, a new prognostic factor has been evaluated - the glucose level at hospital discharge. AIM: To assess whether the glucose level at hospital discharge is associated with one-year mortality in patients with DM treated with percutaneous coronary intervention (PCI) for ST-segment elevation MI (STEMI), taking into account hypoglycaemic treatment. METHODS: Consecutive patients with STEMI and DM treated with PCI, who survived hospitalisation, were included in the analysis. Patients were assumed to have DM if previous diagnosis of DM or newly diagnosed DM during hospital stay was noted. Criteria of newly diagnosed DM were as follows: fasting BG >or=7 mmol/l at least twice after acute phase of STEMI, BG >or=11.1 mmol/l in a 2-hour glucose tolerance test performed before discharge. Fasting plasma glucose at hospital discharge was used for analysis. RESULTS: Out of 2762 consecutive patients with STEMI, 565 had DM. In-hospital mortality in this group was 9.4% (53 patients), so the final DM group consisted of 512 patients. After discharge 59 (11.5%) patients died during one-year follow-up. The glucose level at discharge was not an independent prognostic factor of one-year mortality in the whole analysed group, however insulin treatment at discharge was (HR 2.61, 95% CI 1.29-5.29; p=0.008). Afterwards, we undertook multivariate analysis separately in the group treated with insulin (253 patients) and in the group treated with oral drugs or diet only (259 patients). This analysis showed that in the group treated with insulin the glucose level at discharge was not an independent prognostic factor of one-year mortality (HR 1.07, 95% CI 0.95-1.22; p=0.27), whereas in patients treated with hypoglycaemic agents or diet it was significantly associated with a one-year mortality (HR 1.30, 95% CI 1.01-1.68; p=0.049). CONCLUSIONS: 1. Patients with STEMI and DM treated with insulin at hospital discharge have higher risk of death, probably because of more advanced DM and more severe complications, than patients treated with oral drugs or diet. 2. Elevated glucose level at hospital discharge predict one-year mortality only in patients with MI and DM treated with oral drugs or diet.     

Does lack of ST-segment resolution still have prognostic value 6 years after an acute myocardial infarction treated with coronary intervention?

Background

Limited data exist in regard to the correlation between ST-segment resolution (STR) in patients treated with primary percutaneous coronary intervention (pPCI) and very late mortality. The aim of the study was to determine the correlation between STR and 6-year mortality in patients successfully treated with pPCI.

Methods

We prospectively studied a group of 303 patients who had sustained an acute myocardial infarction with ST-segment elevation and subsequently exhibited TIMI 3 flow after pPCI. The patients were analyzed in 2 groups according to STR.

Results

There were 222 patients (73.3%) with STR and 81 patients (26.7%) without it. The mean “pain-to-balloon” time was 4.3 ± 2.1 hours in the former group vs 4.9 ± 2.8 hours in the latter (P = 0.016). In total, 64 people (21%) died during the 6-year follow-up period: 37 (17%) showed STR and 28 (35%) did not (P < 0.001). In multivariate analysis, STR, ejection fraction, and maximum creatine kinase and creatine kinase-MB levels were all associated with death. Anterior myocardial infarction, “pain-to-balloon” time, and ejection fraction were all further associated with lack of STR.

Conclusions

Lack of early STR is associated with significantly higher mortality rates after successful pPCI during a 6-year follow-up period. Absence of an early STR appears to identify patients who are less likely to benefit from the early restoration of infarct-affected artery, possibly due to microvascular damage. STR therefore appears to be a powerful prognostic marker for the occurrence of an acute myocardial infarction 6 years later.     

Impact of early abciximab administration on myocardial reperfusion in patients with ST-segment elevation myocardial infarction pretreated with 600 mg of clopidogrel before percutaneous coronary intervention

Early rapid platelet inhibition with abciximab before primary percutaneous coronary intervention (PPCI) for ST-segment elevation myocardial infarction (STEMI) is suggested as beneficial. In previous studies on early abciximab administration clopidogrel was administered in cathlab in low loading dose. We investigated the role of early abciximab administration on top of early clopidogrel 600 mg loading dose in patients with STEMI treated with PPCI. A total of 73 non-shock STEMI < 6 h patients admitted to remote hospitals with anticipated delay to PPCI < 90 min were randomly assigned to three study groups—24 pts received abciximab before transfer to cathlab (early = group EA), 27 in cathlab during PPCI (late = group LA) and in 22 abciximab administration was left to operator’s discretion during PPCI (selective = SA; given in 22.7% of patients). All patients received clopidogrel (600 mg), aspirin and heparin (70 U/kg) before transfer to cathlab. Angiography revealed more frequent infarct-related artery patency (TIMI 2 + 3: EA vs LA vs SA: 45.8 vs 18.5 vs 13.6%, P = 0.024), better myocardial tissue perfusion (MBG 2 + 3: EA vs LA vs SA: 45.8 vs 14.8 vs 13.6%, P = 0.02) in EA group in baseline angiography. There was no difference in these angiographic parameters and ECG ST-segment resolution after PPCI. In multivariate analysis early abciximab administration was an independent predictor of infarct-related artery patency in baseline angiography (OR 6.5; 95% CI 1.83–23.1; P = 0.004). Early abciximab administration before transfer for PPCI in patients with STEMI pretreated with 600 mg of clopidogrel results in more frequent infarct-related artery patency and better myocardial tissue perfusion before PPCI.     

Emergency physician accuracy in interpreting electrocardiograms with potential ST-segment elevation myocardial infarction: Is it enough?

Background: Electrocardiogram (ECG) interpretation is widely performed by emergency physicians. We aimed to determine the accuracy of interpretation of potential ST-segment elevation myocardial infarction (STEMI) ECGs by emergency physicians. Methods: Thirty-six ECGs resulted in putative STEMI diagnoses were selected. Participants were asked to focus on whether or not the ECG in question met the diagnostic criteria for an acutely blocked coronary artery causing a STEMI. Based on the coronary angiogram, a binary outcome of accurate versus inaccurate ECG interpretation was defined. We computed the overall sensitivity, specificity, accuracy and 95% confidence intervals (95%CIs) for ECG interpretation. Data on participant training level, working experience and place were collected. Results: 135 participants interpreted 4603 ECGs. Overall sensitivity to identify ‘true’ STEMI ECGs was 64.5% (95%CI: 62.8–66.3); specificity in determining ‘false’ ECGs was 78% (95%CI: 76–80.1). Overall accuracy was modest (69.1, 95%CI: 67.8–70.4). Higher accuracy in ECG interpretation was observed for attending physicians, participants working in tertiary care hospitals and those more experienced. Conclusion: The accuracy of interpretation of potential STEMI ECGs was modest among emergency physicians. The study supports the notion that ECG interpretation for establishing a STEMI diagnosis lacks the necessary sensitivity and specificity to be considered a reliable ‘stand-alone’ diagnostic test.     

Regionalization of care for ST-segment elevation myocardial infarction: is it too soon?

Interest in regionalization of the care of acute ST-segment elevation myocardial infarction (STEMI) has gained momentum recently. Optimal treatment of STEMI involves balancing time to treatment and reperfusion options. Primary percutaneous coronary intervention, when performed in a timely fashion, has been shown to be more effective than fibrinolysis. However, numerous practical barriers prevent many STEMI patients from receiving primary percutaneous coronary intervention. In an effort to increase beneficial primary percutaneous coronary intervention administration to STEMI patients, health care leaders have proposed regionalized STEMI care networks with advanced emergency medical services (EMS) involvement. Constructing regionalized STEMI networks presents a policy challenge because this shift in STEMI care would require changes in current EMS and emergency medicine practices. Therefore, we present various perspectives and issues that decisionmakers and system organizers must address properly before deciding whether to adopt this new model of care. Reorganizing STEMI care in a manner analogous to how trauma and stroke care are currently triaged and treated appeals intuitively; however, given the absence of evidence that STEMI regionalization actually improves patient outcomes and is cost-effective, more research is needed to determine whether STEMI regionalization is an efficient model for providing evidence-based care. The concept of STEMI regionalization represents an effort to inform policy according to evidence-based medicine, but real-world quality, geospatial, financial, cost, business, resource, and practice barriers present obstacles to implementing this concept efficiently and effectively.     

Is it possible to simplify risk stratification scores for patients with ST-segment elevation myocardial infarction undergoing primary angioplasty?

IntroductionThere are several risk scores for stratification of patients with ST-segment elevation myocardial infarction (STEMI), the most widely used of which are the TIMI and GRACE scores. However, these are complex and require several variables. The aim of this study was to obtain a reduced model with fewer variables and similar predictive and discriminative ability.MethodsWe studied 607 patients (age 62 years, SD=13; 76% male) who were admitted with STEMI and underwent successful primary angioplasty. Our endpoints were all-cause in-hospital and 30-day mortality. Considering all variables from the TIMI and GRACE risk scores, multivariate logistic regression models were fitted to the data to identify the variables that best predicted death.ResultsCompared to the TIMI score, the GRACE score had better predictive and discriminative performance for in-hospital mortality, with similar results for 30-day mortality. After data modeling, the variables with highest predictive ability were age, serum creatinine, heart failure and the occurrence of cardiac arrest. The new predictive model was compared with the GRACE risk score, after internal validation using 10-fold cross validation. A similar discriminative performance was obtained and some improvement was achieved in estimates of probabilities of death (increased for patients who died and decreased for those who did not).ConclusionIt is possible to simplify risk stratification scores for STEMI and primary angioplasty using only four variables (age, serum creatinine, heart failure and cardiac arrest). This simplified model maintained a good predictive and discriminative performance for short-term mortality.     

Increased interleukin-1β levels are associated with left ventricular hypertrophy and remodelling following acute ST segment elevation myocardial infarction treated by primary percutaneous coronary intervention

Abstract. Ørn S, Ueland T, Manhenke C, Sandanger Ø, Godang K, Yndestad A, Mollnes TE, Dickstein K, Aukrust P (Stavanger University Hospital, Stavanger; Oslo University Hospital Rikshospitalet; University of Bergen, Bergen; University of Oslo; Oslo; Norway). Increased interleukin‐1β levels are associated with left ventricular hypertrophy and remodelling following acute ST segment elevation myocardial infarction treated by primary percutaneous coronary intervention. J Intern Med 2012; 272: 267–276. Objectives. To assess the relationship between interleukin (IL)‐1‐related molecules, infarct size and left ventricular (LV) remodelling following acute myocardial infarction (MI). Methods. Forty‐two patients with first‐time diagnosis of ST segment elevation MI (STEMI), with a single occluded vessel successfully revascularized by primary percutaneous coronary intervention (PCI), were recruited to this observational study conducted at a university teaching hospital and followed for 1 year. Main outcome measures. Plasma levels of IL‐1β, IL‐1 receptor antagonist (IL‐1Ra), IL‐18 and caspase‐1 were analysed before and 2 days, 1 week and 2 months after PCI. Serial cardiac magnetic resonance imaging (CMR) was used for the assessment of infarct size and LV remodelling. CMR findings at 1 year was the primary outcome variable. Results. Univariate analysis showed that IL‐1‐related mediators were strongly (IL‐1 β), moderately (caspase‐1) and weakly (IL‐1Ra) associated with impaired myocardial function and noninfarct mass, but not infarct size, 1 year after reperfused STEMI. In multivariate analyses, troponin T predicted LV ejection fraction (LVEF), infarct size and LV end‐diastolic (LVEDVi) and end‐systolic volume index (LVESVi). However, significant additional variance was explained by IL‐1β, IL‐18 and caspase‐1. IL‐1β levels at 2 months, IL‐18 at 2 days and pre‐PCI caspase‐1 were predictors of LVEF. Caspase‐1 and in particular IL‐1β at 2 days were the only predictors of noninfarct mass. IL‐1β and IL‐18 at 2 days were predictors of LVEDVi, whilst pre‐PCI levels of IL‐1β contributed to prediction of LVESVi. By contrast, pro‐B‐type natriuretic peptide, C‐reactive protein, IL‐6 and transforming growth factor‐β1 (TGF‐β1) had no or only a weak (TGF‐β1) association with these CMR parameters in multivariate analyses. Conclusions. IL‐1β levels after STEMI were strongly associated with impaired myocardial function and noninfarct LV mass after 1 year, suggesting a potential role for IL‐1β as a predictor of maladaptive myocardial remodelling following reperfused MI.     

ST-segment elevation in precordial leads: anterior or right ventricular myocardial infarction?

Isolated acute right ventricular (RV) infarction is rare, and ECG diagnosis may be difficult. We report two cases of acute myocardial infarction with ST-segment elevation in anterior precordial leads caused by such an RV involvement. Potential mechanisms for the relationship are given.     

Three-year clinical outcome with the Endeavor™ zotarolimus-eluting stent in primary percutaneous coronary intervention for ST elevation myocardial infarction: the Endeavor™ primary PCI study (E-PPCI)

Primary percutaneous coronary intervention (PPCI) is superior to thrombolysis in STEMI (ST segment elevation myocardial infarction) patients. Data on late stent thrombosis (ST) have raised concerns regarding the use of drug-eluting stents during PPCI. We report the first 3-year clinical evaluation of the zotarolimus-eluting stent (ZES) in patients undergoing PPCI for STEMI, a single-center, prospective cohort study of consecutive patients admitted with STEMI. All underwent PPCI within 12 hours of symptoms; each received one or more ZES in one or more target lesions. All patients received aspirin 300 mg, clopidogrel 600 mg, abciximab, and unfractionated heparin. A total of 102 STEMI patients (76 male, mean 62 years) received 162 ZES (mean 1.6 stents/patient). Median call-to-balloon time was 123 (102-152) minutes. Thirty-day combined major adverse cardiovascular event (MACE) rate was 3.9% (n = 4). Subacute ST occurred in 2 patients (1.96%). Combined MACE rates at 12 months and 3 years were 7.8% (n = 8) and 13.7% (n = 14). Late ST occurred in 1 patient (1%) with no occurrence of very late ST. This is the first 3-year report of the use of the ZES in an unselected, consecutive PPCI population. Overall 3-year incidence of MACE and target lesion revascularization (5.9%) was low, and was comparable to that seen with sirolimus- and paclitaxel-eluting stents in randomized controlled trials. At 3 years there was no occurrence of very late ST.