Renal Protection Using Remote Ischemic Peri‐Conditioning During Inter‐Facility Helicopter Transport of Patients With ST‐Segment Elevation Myocardial Infarction: A Retrospective Study

Objective

To assess the impact of remote ischemic peri‐conditioning (RIPC) during inter‐facility air medical transport of ST‐segment elevation myocardial infarction (STEMI) patients on the incidence of acute kidney injury (AKI) following primary percutaneous coronary intervention (pPCI).

Background

STEMI patients who receive pPCI have an increased risk of AKI for which there is no well‐defined prophylactic therapy in the setting of emergent pPCI.

Methods

Using the ACTION Registry‐GWTG, we evaluated the impact of RIPC applied during inter‐facility helicopter transport of STEMI patients from non‐PCI capable hospitals to 2 PCI‐hospitals in the United States between March, 2013 and September, 2015 on the incidence of AKI following pPCI. AKI was defined as ≥0.3 mg/dL increase in creatinine within 48–72 hours after pPCI.

Results

Patients who received RIPC (n = 127), compared to those who did not (n = 92), were less likely to have AKI (11 of 127 patients [8.7%] vs. 17 of 92 patients [18.5%]; adjusted odds ratio = 0.32, 95% CI 0.12–0.85, P = 0.023) and all‐cause in‐hospital mortality (2 of 127 patients [1.6%] vs. 7 of 92 patients [7.6%]; adjusted odds ratio = 0.14, 95% CI 0.02–0.86, P = 0.034) after adjusting for socio‐demographic and clinical characteristics. There was no difference in hospital length of stay (3 days [interquartile range, 2–4] vs. 3 days [interquartile range, 2–5], P = 0.357) between the 2 groups.

Conclusion

RIPC applied during inter‐facility helicopter transport of STEMI patients for pPCI is associated with lower incidence of AKI and in‐hospital mortality. The use of RIPC for renal protection in STEMI patients warrants further in depth investigation.

     

Impact of Scheduled Angiographic Follow‐Up in Patients Treated With Primary Percutaneous Coronary Intervention for ST‐Segment Elevation Myocardial Infarction

Routine scheduled angiographic follow‐up (SAF) after percutaneous coronary intervention (PCI) has been associated with a higher rate of target vessel revascularization (TVR). Its benefits are not known. SAF at 13 months after ST‐segment elevation myocardial infarction (STEMI) was planned in the first 1,800 successfully stented patients enrolled in the Harmonizing Outcomes with RevascularIZatiON and Stents in Acute Myocardial Infarction (HORIZONS‐AMI) trial. We compared the outcomes of patients with and without SAF at 1 year (before SAF) and at 3 years (after SAF). There were 1,197 patients (66.5% of expected) with and 2,207 patients without SAF. Prior to SAF, the 1‐year composite rate of death or myocardial infarction (MI) was not significantly different between the 2 groups (2.7% vs. 3.9%, respectively, P = 0.06), although the rate of death was lower (0.1% vs. 2.2%, P < 0.0001), nor were there differences in the 1‐year rates of TVR, stent thrombosis or major adverse cardiac and cerebral events). At 3 years, death or MI rates were again similar between the groups (8.3% vs. 9.5%, P = 0.22), but TVR was more common in the SAF group (17.0% vs. 8.6%, P < 0.0001), due to an increase in TVR at time of SAF. In the SAF group, patients in whom TVR was performed before or after the 13‐month SAF window had markedly higher 3‐year rates of MI and stent thrombosis than patients in whom TVR was performed during SAF or not at all. In conclusion, SAF after primary PCI in STEMI is associated with doubling of the rate of revascularization without an improvement in death or MI, and therefore cannot be recommended.

     

Preconditioning Reduces QTc Value in Patients with First Non‐ST‐Segment Elevation Myocardial Infarction (NSTEMI)

Background: Preinfarction angina (PA) consists a strong clinical correlate to ischemic preconditioning (PC) and seems to occur in a bimodal time course. The aim of the study is to evaluate the impact of both forms of PC on QTc value representing myocardial electric stability, in patients with a first NSTEMI. Methods: Forty‐eight patients, with first NSTEMI and poor or no collateral development were enrolled in the study. QTc at admission and discharge were recorded. All patients had comparable admission QTc values and were divided into three groups according to the absence or presence and exact timing of preinfarction angina. The first group consisted of 20 patients who did not report PA (PA?, representing no PC effect); the second group of 12 patients with reported PA within 12 hours prior to admission (12h PA+, representing the classic form of PC); and the third group of 16 patients reporting PA within 12 to 48 hours prior to admission (48‐hour PA+, representing the delayed form of PC). The primary outcome was determined as the effect of PA on QTc value at discharge. Results: Discharge QTc values were significantly reduced in both (PA+) groups compared to (PA?) group (412 ± 50 vs. 455 ± 53 ms, p = 0.015 and 417 ± 29 vs. 455 ± 53 ms, P = 0.033 , respectively). Both groups of (PA+) patients compared to (PA?) patients suffered no arrhythmic events during their hospitalization (0/12 vs. 6/20, P = 0.04 and 0/16 vs. 6/20, P = 0.02 ). Conclusions: Both forms of preconditioning, similarly and significantly reduce QTc value at discharge in patients experiencing a first NSTEMI, suggesting possible protection from future arrhythmic events.     

The Index of Microcirculatory Resistance Postpercutaneous Coronary Intervention Predicts Left Ventricular Recovery in Patients With Thrombolyzed ST‐Segment Elevation Myocardial Infarction

Background

The index of microcirculatory resistance (IMR), an invasive measure of microvascular function, has been shown to correlate with clinical outcomes in patients with ST‐segment elevation myocardial infarction (STEMI). The aim of this study is to evaluate the predictive value of IMR on left ventricular recovery in patients undergoing a pharmacoinvasive strategy for STEMI.

Methods

The index of microcirculatory resistance was assessed following percutaneous coronary intervention (PCI) in 31 patients with STEMI who were initially managed with thrombolysis. Other markers of microvascular function such as coronary flow reserve (CFR), TIMI flow grade, corrected TIMI frame count (cTFC), and ST‐segment resolution were also recorded. All indices were evaluated against measures of left ventricular function and recovery 3 months postindex event.

Results

The IMR correlated with left ventricular function, as assessed by wall motion score and ejection fraction at 3‐month follow‐up (r = 0.652, P = 0.005; r = ?0.452, P = 0.011, respectively). The traditional methods of assessing microvascular function, such as CFR, TIMI flow grade, cTFC, and ST‐segment resolution did not correlate with wall motion score and ejection fraction at 3 months. Post‐PCI IMR was significantly lower in those patients with left ventricular recovery at 3 months (18 U vs 39 U, P < 0.001). The optimal cut‐off value for post‐PCI IMR and left ventricular recovery was 32 U. In patients in whom the IMR was greater than 32 U, the percent change in ejection fraction was significantly lower than in those patients in whom the IMR was less than 32 U (2 ± 11 vs 12 ± 8, P = 0.012).

Conclusions

In patients presenting with STEMI initially managed with thrombolysis and subsequently undergoing PCI, IMR correlates with measures of left ventricular function and has the potential to predict left ventricular recovery at 3 months. (J Interven Cardiol 2016;29:146–154)

     

Outcome of Early Revascularization Surgery in Patients with ST‐Elevation Myocardial Infarction

Objectives

To compare morbidity and mortality of patients with ST‐elevation myocardial infarction (MI) undergoing coronary artery bypass graft (CABG) surgery within 24 hours with those who had surgery delayed >24 hours.

Background

Patients with ST‐elevation MI are currently managed by emergency percutaneous coronary intervention (PCI). If PCI is unsuccessful, or if there is severe coronary artery disease not amenable to PCI, CABG is considered. If the patient is clinically stable, surgeons wait several days before performing surgery, as very early surgery carries a prohibitive risk.

Methods

One hundred and eighty‐four patients with acute ST elevation MI (STEMI) who had undergone CABG were divided into two groups based on their surgery timing (<24 hours vs. >24 hours). Mortality and complication rates were studied between the two groups by Fischer test. Time‐to‐event analyses were performed for five primary variables: all‐cause mortality, cardiac events, congestive heart failure, stroke, and renal failure.

Results

At one month post‐CABC, all‐cause mortality was noted in 10.6% of patients who had CABG within 24 hours of STEMI diagnosis, compared with 8.9% in patients who had CABG after 24 hours (P = 0.3). Cardiac events including re‐exploration, atrial fibrillation, graft occlusion, and arrhythmias requiring shock occurred in 17.1% versus 13.9% between the two groups, respectively (P = 0.68). One year post‐coronary artery bypass surgery, there was no difference in individual or combined events between the two groups.

Conclusions

In patients with ST‐elevation myocardial infarction who required emergency coronary artery bypass surgery, there was no difference in procedure complications or mortality between early (within 24 hours) or later (more than 24 hours). That was noted at one month and one year after the index myocardial infarction. (J Interven Cardiol 2015;28:14–23)

     

Culprit Vessel Only vs Immediate Complete Revascularization in Patients With Acute ST‐Segment Elevation Myocardial Infarction: Systematic Review and Meta‐Analysis

Although multivessel coronary artery disease has been associated with poor health outcomes in patients with acute ST‐segment elevation myocardial infarction (STEMI), the optimal approach to revascularization remains uncertain. The objective of this review was to determine the benefits and harms of culprit vessel only vs immediate complete percutaneous coronary intervention (PCI) in patients with acute STEMI. We searched MEDLINE, EMBASE, the Cochrane Register of Controlled Trials, and the Cumulative Index to Nursing and Allied Health Literature (CINAHL) for randomized controlled trials (RCTs). Teams of 2 reviewers, independently and in duplicate, screened titles and abstracts, completed full‐text reviews, and abstracted data. We calculated pooled risk ratios (RRs) and associated 95% confidence intervals (CIs) using random‐effect models for nonfatal myocardial infarction (MI), revascularization, cardiovascular mortality, all‐cause mortality, and adverse events, and used the GRADE approach to rate confidence in estimates of effect. Of 341 patients randomized to complete revascularization and followed to study conclusion, 31 experienced revascularization, as did 80 of 324 randomized to culprit vessel only revascularization (RR: 0.35, 95% CI: 0.24‐0.53). Ten patients in the complete revascularization group and 28 patients in the culprit vessel only revascularization group experienced nonfatal MI (RR: 0.35, 95% CI: 0.17‐0.72). All‐cause mortality and cardiac deaths did not differ between groups (RR: 0.69, 95% CI: 0.40‐1.21 for all‐cause mortality; RR: 0.48, 95% CI: 0.22‐1.04 for cardiac deaths). Pooled data from 3 RCTs suggest that immediate complete revascularization probably reduces revascularization in patients with acute STEMI; although results suggest possible benefits on MI and death, confidence in estimates is low.