ACCF/AHA/SCAI 2007 Update of the Clinical Competence Statement on Cardiac Interventional Procedures

Impact of hospital volume on outcomes of percutaneous ASD/PFO closure in pediatric patients

BACKGROUND

We investigated the effect of hospital volume on percutaneous closure of atrial septal defect/patent foramen ovale (ASD) among pediatric patients.

METHODS

We identified patients undergoing percutaneous closure of ASD with device using International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) procedure code 35.52 from the National Inpatient Sample, years 2002-2011. Patients with age ≤ 18 years and primary diagnosis code 745.5 for ASD were included. Hospital volume was calculated using unique identification numbers and divided into tertiles for analysis. Multivariate regression analysis was performed to determine independent predictors of procedure-related complications which were coded using specific codes released by Healthcare Cost and Utilization Project.

RESULTS

6162 percutaneous ASD closure procedures were analyzed. There was no mortality associated with percutaneous ASD closure. Cardiac complications (9.5%) were most common. On multivariate analysis, age increment of 3 years decreased the odds of developing complications (OR 0.83, 95% CI 0.79-0.87, P < 0.001). Odds of developing complications in the 2nd (OR 0.74, 95% CI 0.62-0.89, P = 0.007) and 3rd tertiles (OR 0.34, 95% CI 0.27-0.42, P < 0.001) were lower as compared to the 1st tertile of hospital volume.

CONCLUSION

Increasing annual hospital volume is an independent predictor of lower complication rates in percutaneous ASD closure cases with no associated mortality in pediatric patients.

Remote ischaemic conditioning reduces infarct size in animal in vivo models of ischaemia-reperfusion injury: a systematic review and meta-analysis

Aims

The potential of remote ischaemic conditioning (RIC) to ameliorate myocardial ischaemia-reperfusion injury (IRI) remains controversial. We aimed to analyse the pre-clinical evidence base to ascertain the overall effect and variability of RIC in animal in vivo models of myocardial IRI. Furthermore, we aimed to investigate the impact of different study protocols on the protective utility of RIC in animal models and identify gaps in our understanding of this promising therapeutic strategy.

Methods and results

Our primary outcome measure was the difference in mean infarct size between RIC and control groups in in vivo models of myocardial IRI. A systematic review returned 31 reports, from which we made 22 controlled comparisons of remote ischaemic preconditioning (RIPreC) and 21 of remote ischaemic perconditioning and postconditioning (RIPerC/RIPostC) in a pooled random-effects meta-analysis. In total, our analysis includes data from 280 control animals and 373 animals subject to RIC. Overall, RIPreC reduced infarct size as a percentage of area at risk by 22.8% (95% CI 18.8–26.9%), when compared with untreated controls (P < 0.001). Similarly, RIPerC/RIPostC reduced infarct size by 22.2% (95% CI 17.1–25.3%; P < 0.001). Interestingly, we observed significant heterogeneity in effect size (T2 = 92.9% and I2 = 99.4%; P < 0.001) that could not be explained by any of the experimental variables analysed by meta-regression. However, few reports have systematically characterized RIC protocols, and few of the included in vivo studies satisfactorily met study quality requirements, particularly with respect to blinding and randomization.

Conclusions

RIC significantly reduces infarct size in in vivo models of myocardial IRI. Heterogeneity between studies could not be explained by the experimental variables tested, but studies are limited in number and lack consistency in quality and study design. There is therefore a clear need for more well-performed in vivo studies with particular emphasis on detailed characterization of RIC protocols and investigating the potential impact of gender. Finally, more studies investigating the potential benefit of RIC in larger species are required before translation to humans.

Effect of Remote Ischaemic Preconditioning on Liver Injury in Patients Undergoing Major Hepatectomy for Colorectal Liver Metastasis: A Pilot Randomised Controlled Feasibility Trial

Background

Liver resection produces excellent long-term survival for patients with colorectal liver metastases but is associated with significant morbidity and mortality from ischaemia reperfusion injury (IRI). Remote ischaemic preconditioning (RIPC) can reduce the effect of IRI. This pilot randomised controlled trial evaluated RIPC in patients undergoing major hepatectomy at the Royal Free Hospital, London.

Methods

Sixteen patients were randomised to RIPC or sham control. RIPC was induced through three 10-min cycles of alternate ischaemia and reperfusion to the leg. At baseline and immediately post-resection, transaminases and indocyanine green (ICG) clearance were measured.

Findings

The RIPC group had lower ALT and AST levels immediately post-resection (ALT: 43% lower 497 ± 165 vs 889 ± 170 IU/L; p = 0.019 AST: 54% lower 408 ± 166 vs 836 ± 167 IU/L; p = 0.001) and at 24 h (ALT: 41% lower 412 ± 144 vs 698 ± 137 IU/L; p = 0.026 AST: 50% lower 316 ± 116 vs 668 ± 115 IU/L; p = 0.02). ICG clearance was reduced in controls versus RIPC immediately after resection (ICG-PDR: 11.1 ± 1.1 vs 16.5 ± 1.4%/min; p = 0.035).

Conclusions

This pilot study shows that RIPC has potential to reduce liver injury following hepatectomy justifying a prospective RCT powered to demonstrate clinical benefits.

From Protecting the Heart to Improving Athletic Performance - the Benefits of Local and Remote Ischaemic Preconditioning

Remote Ischemic Preconditioning (RIPC) is a non-invasive cardioprotective intervention that involves brief cycles of limb ischemia and reperfusion. This is typically delivered by inflating and deflating a blood pressure cuff on one or more limb(s) for several cycles, each inflation-deflation being 3-5 min in duration. RIPC has shown potential for protecting the heart and other organs from injury due to lethal ischemia and reperfusion injury, in a variety of clinical settings. The mechanisms underlying RIPC are under intense investigation but are just beginning to be deciphered. Emerging evidence suggests that RIPC has the potential to improve exercise performance, via both local and remote mechanisms. This review discusses the clinical studies that have investigated the role of RIPC in cardioprotection as well as those studying its applicability in improving athletic performance, while examining the potential mechanisms involved.

Clinical applications of remote ischaemic preconditioning in native and transplant acute kidney injury

Ischaemia-reperfusion (IR) injury is a composite of the injury sustained during a period of reduced or absent blood flow to a tissue or organ and the additional insult sustained upon reperfusion that limits the amount of tissue that can be salvaged. IR injury plays a central role in both native and transplant acute kidney injury (AKI). Native AKI is associated with increased morbidity and mortality in hospital inpatients, and transplant AKI contributes to graft dysfunction, ultimately limiting graft longevity. In this review, we discuss the potential therapeutic benefits of a cost-effective and low-risk intervention, remote ischaemic preconditioning (RIPC), and its applicability in the prevention and reduction of AKI.

Influence of hospital volume on outcomes of percutaneous atrial septal defect and patent foramen ovale closure: a 10-years US perspective

BACKGROUND

Contemporary data regarding percutaneous closure of atrial septal defect/patent foramen ovale (ASD/PFO) are lacking. We evaluated the current trends in utilization of ASD/PFO closure in adults and investigated the effect of annual hospital volume on in-hospital outcomes.

METHODS

We queried the Nationwide Inpatient Sample between the years 2001 and 2010 using the International Classification of Diseases (ICD-9-CM) procedure code for percutaneous closure of ASD/PFO with device. Hierarchical mixed effects models were generated to identify the independent multivariate predictors of outcomes.

RESULTS

A total of 7,107 percutaneous ASD/PFO closure procedures (weighted n = 34,992) were available for analysis. A 4.7-fold increase in the utilization of this procedure from 3/million in 2001 to 14/million adults in 2010 in US (P < 0.001) was noted. Overall, percutaneous ASD/PFO closure was associated with 0.5% mortality and 12% in-hospital complications. The utilization of intracardiac echocardiography (ICE) increased 15 fold (P < 0.001) during the study period. The procedures performed at the high volume hospitals [2nd (14-37 procedures/year) and 3rd (>38 procedures/year) tertile] were associated with significant reduction in complications, length of stay and cost of hospitalization when compared to those performed at lowest volume centers (<13 procedures/year). Majority (70.5%) of the studied hospitals were found to be performing <10 procedures/year hence deviating from the ACC/AHA/SCAI clinical competency guidelines.

CONCLUSIONS

Low hospital volume is associated with an increased composite (mortality and procedural complications) adverse outcome following ASD/PFO closure. In the interest of patient safety, implementation of the current guidelines for minimum required annual hospital volume to improve clinical outcomes is warranted.

Remote ischemic conditioning: from experimental observation to clinical application: report from the 8th Biennial Hatter Cardiovascular Institute Workshop

In 1993, Przyklenk and colleagues made the intriguing experimental observation that ‘brief ischemia in one vascular bed also protects remote, virgin myocardium from subsequent sustained coronary artery occlusion’ and that this effect ‘…. may be mediated by factor(s) activated, produced, or transported throughout the heart during brief ischemia/reperfusion’. This seminal study laid the foundation for the discovery of ‘remote ischemic conditioning’ (RIC), a phenomenon in which the heart is protected from the detrimental effects of acute ischemia/reperfusion injury (IRI), by applying cycles of brief ischemia and reperfusion to an organ or tissue remote from the heart. The concept of RIC quickly evolved to extend beyond the heart, encompassing inter-organ protection against acute IRI. The crucial discovery that the protective RIC stimulus could be applied non-invasively, by simply inflating and deflating a blood pressure cuff placed on the upper arm to induce cycles of brief ischemia and reperfusion, has facilitated the translation of RIC into the clinical setting. Despite intensive investigation over the last 20 years, the underlying mechanisms continue to elude researchers. In the 8th Biennial Hatter Cardiovascular Institute Workshop, recent developments in the field of RIC were discussed with a focus on new insights into the underlying mechanisms, the diversity of non-cardiac protection, new clinical applications, and large outcome studies. The scientific advances made in this field of research highlight the journey that RIC has made from being an intriguing experimental observation to a clinical application with patient benefit.

Ischaemic conditioning strategies for the nephrologist: a promise lost in translation?

Over the last quarter of a century, a huge effort has been made to develop interventions that can minimise ischaemia reperfusion injury. The most potent of these are the ischaemic conditioning strategies, which comprise ischaemic preconditioning, remote ischaemic preconditioning and ischaemic postconditioning. While much of the focus for these interventions has been on protecting the myocardium, other organs including the kidney can be similarly protected. However, translation of these beneficial effects from animal models into routine clinical practice has been less straightforward than expected. In this review, we examine the role of ischaemic conditioning strategies in reducing tissue injury from the 'bench to the bedside' and discuss the barriers to their greater translation.

The RIPOST-MI study, assessing remote ischemic perconditioning alone or in combination with local ischemic postconditioning in ST-segment elevation myocardial infarction

Local ischemic postconditioning (IPost) and remote ischemic perconditioning (RIPer) are promising cardioprotective therapies in ST-elevation myocardial infarction (STEMI). We aimed: (1) to investigate whether RIPer initiated at the catheterization laboratory would reduce infarct size, as measured using serum creatine kinase-MB isoenzyme (CK-MB) release as a surrogate marker; (2) to assess if the combination of RIPer and IPost would provide an additional reduction. Patients (n = 151) were randomly allocated to one of the following groups: (1) control group, percutaneous transluminal coronary angioplasty (PTCA) alone; (2) RIPer group, PTCA combined with RIPer, consisting of three cycles of 5-min inflation and 5-min deflation of an upper-arm blood-pressure cuff initiated before reperfusion; (3) RIPer+IPost group, PTCA combined with RIPer and IPost, consisting of four cycles of 1-min inflation and 1-min deflation of the angioplasty balloon. The CK-MB area under the curve (AUC) over 72 h was reduced in RIPer, and RIPer+IPost groups, by 31 and 29 %, respectively, compared to the Control group; however, CK-MB AUC differences between the three groups were not statistically significant (p = 0.06). Peak CK-MB, CK-MB AUC to area at risk (AAR) ratio, and peak CK-MB level to AAR ratio were all significantly reduced in the RIPer and RIPer+IPost groups, compared to the Control group. On the contrary, none of these parameters was significantly different between RIPer+IPost and RIPer groups. To conclude, starting RIPer therapy immediately prior to revascularization was shown to reduce infarct size in STEMI patients, yet combining this therapy with an IPost strategy did not lead to further decrease in infarct size.

Preconditioning the human brain: practical considerations for proving cerebral protection

Ischemic preconditioning has evolved as one of the most powerful strategies for cerebral protection in laboratory models of ischemia. Translating the success of laboratory studies to human cerebral protection will necessitate an approximation of laboratory conditions. This would require a practical, easily implemented method of preconditioning and clinical settings in which cerebral ischemia is anticipated, thereby allowing cerebral preconditioning prior to ischemia onset. Remote limb ischemic preconditioning is readily instituted and used in several ongoing cardiac studies for ischemic myocardial protection. It is a potentially promising intervention for brain protection as well. Suitable clinical settings, in which a preliminary study of ischemic preconditioning in neurological disorders appears feasible, include carotid endarterectomy or stenting, cardiac surgery, and subarachnoid hemorrhage with the accompanying risk of vasospasm. These are settings, in which there is substantial risk of brain ischemia, which occurs over a short and predictable period, allowing for preconditioning to be implemented prior to ischemia onset.

Remote ischemic preconditioning and renoprotection: from myth to a novel therapeutic option?

There is currently no effective prophylactic regimen available to prevent contrast-induced AKI (CI-AKI), a frequent and life-threatening complication after cardiac catheterization. Therefore, novel treatment strategies are required to decrease CI-AKI incidence and to improve clinical outcomes in these patients. Remote ischemic preconditioning (rIPC), defined as transient brief episodes of ischemia at a remote site before a subsequent prolonged ischemia/reperfusion injury of the target organ, is an adaptational response that protects against ischemic and reperfusion insult. Indeed, several studies demonstrated the tissue-protective effects of rIPC in various target organs, including the kidneys. In this regard, rIPC may offer a novel noninvasive and virtually cost-free treatment strategy for decreasing CI-AKI incidence. This review evaluates the current experimental and clinical evidence for rIPC as a potential renoprotective strategy, and discusses the underlying mechanisms and key areas for future research.

Does remote ischaemic preconditioning with postconditioning improve clinical outcomes of patients undergoing cardiac surgery? Remote Ischaemic Preconditioning with Postconditioning Outcome Trial

AIMS

The aim of this study was to evaluate whether remote ischaemic preconditioning (RIPC) combined with remote ischaemic postconditioning (RIPostC) improves the clinical outcomes of patients undergoing cardiac surgery.

METHODS AND RESULTS

From June 2009 to November 2010, 1280 patients who underwent elective cardiac surgery were randomized into the RIPC with RIPostC group or the control group in the morning of the surgery. In the RIPC with RIPostC group, four cycles of 5-min ischaemia and 5-min reperfusion were administered twice to the upper limb-before cardiopulmonary bypass (CPB) or coronary anastomoses for RIPC and after CPB or coronary anastomoses for RIPostC. The primary endpoint was the composite of major adverse outcomes, including death, myocardial infarction, arrhythmia, stroke, coma, renal failure or dysfunction, respiratory failure, cardiogenic shock, gastrointestinal complication, and multiorgan failure. Remote ischaemic preconditioning with RIPostC did not reduce the composite outcome compared with the control group (38.0 vs. 38.1%, respectively; P = 0.998) and there was no difference in each major adverse outcome. The intensive care unit and hospital stays were not different between the two groups. However, in the off-pump coronary artery bypass surgery subgroup, multivariate logistic regression analysis revealed that RIPC with RIPostC was related to increased composite outcome (odds ratio: 1.54; 95% confidence interval: 1.02-2.30; P = 0.038).

CONCLUSION

Remote ischaemic preconditioning with RIPostC by transient upper limb ischaemia did not improve clinical outcome in patients who underwent cardiac surgery.

Aldehyde dehydrogenase-2 inhibition blocks remote preconditioning in experimental and human models

Mitochondrial aldehyde dehydrogenase-2 (ALDH-2) is involved in preconditioning pathways, but its role in remote ischaemic preconditioning (rIPC) is unknown. We investigated its role in animal and human models of rIPC. (i) In a rabbit model of myocardial infarction, rIPC alone reduced infarct size [69 ± 5.8 % (n = 11) to 40 ± 6.5 % (n = 12), P = 0.019]. However, rIPC protection was lost after pre-treatment with the ALDH-2 inhibitor cyanamide (62 ± 7.6 % controls, n = 10, versus 61 ± 6.9 % rIPC after cyanamide, n = 10, P > 0.05). (ii) In a forearm plethysmography model of endothelial ischaemia-reperfusion injury, 24 individuals of Asian ethnic origin underwent combined rIPC and ischaemia-reperfusion (IR). 11 had wild-type (WT) enzyme and 13 carried the Glu504Lys (ALDH2*2) polymorphism (rendering ALDH-2 functionally inactive). In WT individuals, rIPC protected against impairment of response to acetylcholine (P = 0.9), but rIPC failed to protect carriers of Glu504Lys polymorphism (P = 0.004). (iii) In a second model of endothelial IR injury, 12 individuals participated in a double-blind placebo-controlled crossover study, receiving the ALDH-2 inhibitor disulfiram 600 mg od or placebo for 48 h prior to assessment of flow-mediated dilation (FMD) before and after combined rIPC and IR. With placebo, rIPC was effective with no difference in FMD before and after IR (6.18 ± 1.03 % and 4.76 ± 0.93 % P = 0.1), but disulfiram inhibited rIPC with a reduction in FMD after IR (7.87 ± 1.27 % and 3.05 ± 0.53 %, P = 0.001). This study demonstrates that ALDH-2 is involved in the rIPC pathway in three distinct rabbit and human models. This has potential implications for future clinical studies of remote conditioning.

Remote ischemic preconditioning in percutaneous coronary revascularization: a double-blind randomized controlled clinical trial

OBJECTIVE

To assess the impact of pre-procedural remote ischemic preconditioning on the incidence of myocardial complications following percutaneous coronary intervention.

BACKGROUND

Ischemic preconditioning of a remote vascular territory improves the subsequent ischemic tolerance of distant organs.

METHOD

The Myocardial Event Reduction with Ischemic Preconditioning Therapy (MERIT) trial recruited 80 consecutive patients undergoing elective angioplasty with drug-eluting stents to receive two 5-min lower limb tourniquet occlusions or an un-inflated tourniquet (controls) 1 h before the procedure. The primary outcome was troponin T level at 24 h. Secondary outcomes were intra-procedural chest pain and ST-segment deviation.

RESULTS

6 patients in the control group and 2 in the ischemic preconditioning group had pre-procedural raised troponin T (p = 0.23). This increased to 16 (40%) in the control group and 5 (12.5%) in the study group at 24 h (p = 0.01). Fewer patients in the study group experienced intra-procedural chest pain (1 vs. 7, p = 0.056). Mean ST-segment deviation time was 13 ± 35 s in the study group and 58 ± 118 s in the control group (p = 0.02). At a mean follow-up of 11 months, the major adverse cardiac event rate did not differ significantly between the groups.

CONCLUSION

These data suggest that ischemic preconditioning reduces the absolute risk of post-procedure cardiomyocyte necrosis by 27.5%, and reduces intra-procedural chest pain and ST-segment deviation in patients undergoing percutaneous coronary interventions. We suggest its routine use in percutaneous coronary intervention, although the long-term prognostic impact in this patient group warrants further investigation.

Peri-operative interventions, but not inflammatory mediators, increase risk of acute kidney injury after cardiac surgery: a prospective cohort study

PURPOSE

Cardiopulmonary bypass (CPB)-related inflammatory response might be one mechanism by which cardiac surgery associated acute kidney injury (CS-AKI) occurs. Interventions that may attenuate inflammation, including glucocorticoids or phosphodiesterase inhibitors, could therefore have a role in its prevention. We aimed to determine the role of inflammatory mediators in CS-AKI in children and the efficacy of commonly used peri-operative interventions to reduce CS-AKI risk.

METHODS

We prospectively studied 109 children undergoing heart surgery. Using regression modeling (adjusting for covariates), we (1) evaluated the association between inflammatory mediators [interleukin (IL)-6, IL-8, C-reactive protein, and tumor necrosis factor-α levels] and CS-AKI, and (2) evaluated risk/prevention factors for CS-AKI including glucocorticoid and milrinone administration. CS-AKI was defined based on pRIFLE methods.

RESULTS

CS-AKI occurred in 68% of children. No inflammatory mediator measured had an independent association with CS-AKI. Higher pre-operative glomerular filtration rate (GFR), sustained decrease in mean arterial pressure during CPB, post-operative single ventricle physiology, deep hypothermic circulatory arrest, and milrinone use at 24 h post-operatively were significant independent predictors of CS-AKI. Intra-operative steroid administration had no effect on the rate of CS-AKI.

CONCLUSIONS

Although inflammatory mediators are up-regulated following CPB, we found no association between levels of inflammatory cytokines and CS-AKI. CS-AKI has complex pathophysiology and the observation that milrinone was associated with increased AKI risk (and that higher GFR predicts more injury) suggests that mechanisms beyond inflammation play a significant role. Intra-operative administration of glucocorticoid does not appear to be an effective intervention for reducing the risk of CS-AKI.

Remote ischemic preconditioning regulates HIF-1α levels, apoptosis and inflammation in heart tissue of cardiosurgical patients: a pilot experimental study

Transient episodes of ischemia in a remote organ (remote ischemic preconditioning, RIPC) bears the potential to attenuate myocardial injury, but the underlying mechanisms are only poorly understood. In the pilot experimental study presented we investigated cellular and molecular effects of RIPC in heart tissue of cardiosurgical patients with cardiopulmonary bypass (CPB) and focussed on apoptotic events, local and systemic inflammation as well as the regulation of the hypoxia induced factor-1α (HIF-1α). RIPC was induced by four 5-min cycles of transient upper limb ischemia/reperfusion using a blood-pressure cuff. Right atrial tissue and serum were obtained from patients receiving RIPC (N = 32) and control patients (N = 29) before and after CPB. RIPC patients showed reduced troponin T serum concentrations in the first 48 h after surgery (P < 0.05 vs. control) indicating cardioprotective effects of RIPC. Samples from RIPC patients that were collected before CPB contained significantly increased amounts of HIF-1α and procaspase-3 (HIF-1α: P < 0.05 vs. control, procaspase-3: P < 0.05 vs. control), whereas activities of caspases 3 and 7 were by trend reduced. Samples from RIPC patients that were taken after CPB showed an increased activity of myeloperoxidase (P < 0.05 vs. control; P < 0.05 vs. RIPC before CPB) as well as elevated tissue concentrations of the interleukin (IL)-1β (P < 0.05 vs. RIPC before CPB). Serum levels of IL-8, IL-1β and TNFα were significantly increased in RIPC patients before CPB (P < 0.05 vs. control before CPB). In summary, RIPC regulates HIF-1α levels, apoptosis and inflammation in the myocardium of cardiosurgical patients and leads to increased concentrations of circulating cytokines.

Endogenous cardioprotection by ischaemic postconditioning and remote conditioning

Persistent myocardial ischaemia causes cell death if not rescued by early reperfusion. Millions of years in nature's laboratory have evolved protective responses that 'condition' the heart (and other tissues) to adapt to stressors, and these responses are applicable to the relatively new societal stress of myocardial ischaemia and reperfusion injury. Conditioning can be applied before (preconditioning), during (perconditioning), or after (postconditioning) the ischaemic stressor by imposing short periods of non-lethal ischaemia separated by brief periods of reperfusion. This conditioning protects multiple cell types and induces or rebalances a number of physiological and molecular pathways that ultimately attenuate necrosis and apoptosis. The seemingly disparate pathways may converge directly or indirectly on the mitochondria as a final effector, but other pathways not affecting mitochondria broaden the mechanisms of cardioprotection. The potential downsides of imposing even brief ischaemia directly on the heart somewhat tempered the enthusiasm for applying conditioning stimuli to the heart, but this hurdle was surmounted by applying ischaemia to remote organs and tissues in pre-, per-, and postconditioning. Although the clinical translation of remote per- and postconditioning has been rapid compared with classical preconditioning, there are numerous basic questions that require further investigation, and wider adoption awaits large-scale randomized clinical trials. Pharmacological mimetics may provide another important therapeutic approach by which to treat evolving myocardial infarction.

Effects of remote ischemic preconditioning with postconditioning in patients undergoing off-pump coronary artery bypass surgery--randomized controlled trial

BACKGROUND

Myocardial injury is associated with an adverse outcome after off-pump coronary artery bypass graft surgery (OPCAB). The authors conducted a randomized controlled trial to evaluate whether remote ischemic preconditioning (RIPC) with remote ischemic postconditioning (RIPostC) reduces myocardial injury in patients undergoing OPCAB.

METHODS AND RESULTS

Seventy patients scheduled for OPCAB were randomly assigned to an RIPC+RIPostC group (n=35) or a control group (n=35). In the RIPC+RIPostC group, 4 cycles of 5-min ischemia and 5-min reperfusion were done on a lower limb before anastomoses (RIPC) and after anastomoses (RIPostC). RIPC+RIPostC significantly reduced postoperative serum troponin I levels (P=0.001). The area under the curve for postoperative troponin I was 48.7% lower in the RIPC+RIPostC group (median [interquartile range], 21.3 h·ng⁻¹·ml⁻¹, 16.5-53.1 h·ng⁻¹·ml⁻¹ vs. 41.5 h·ng⁻¹·ml⁻¹, 24.6-90.2 h·ng⁻¹·ml⁻¹, P=0.020). There was no significant difference in creatinine levels and PaO₂/F(i)O₂ ratios between the 2 groups.

CONCLUSIONS

RIPC+RIPostC by lower limb ischemia decreased postoperative myocardial enzyme elevation by almost half postoperatively in patients undergoing OPCAB.

Effect of remote ischemic preconditioning on clinical outcomes in patients undergoing coronary artery bypass graft surgery (ERICCA): rationale and study design of a multi-centre randomized double-blinded controlled clinical trial

BACKGROUND

Novel cardioprotective strategies are required to improve clinical outcomes in high risk patients undergoing coronary artery bypass graft (CABG) ± valve surgery. Remote ischemic preconditioning (RIC), in which brief episodes of non-lethal ischemia and reperfusion are applied to the arm or leg, has been demonstrated to reduce perioperative myocardial injury following CABG ± valve surgery. Whether RIC can improve clinical outcomes in this setting is unknown and is investigated in the effect of remote ischemic preconditioning on clinical outcomes (ERICCA) trial in patients undergoing CABG surgery. (ClinicalTrials.gov Identifier: NCT01247545).

METHODS

The ERICCA trial is a multicentre randomized double-blinded controlled clinical trial which will recruit 1,610 high-risk patients (Additive Euroscore ≥ 5) undergoing CABG ± valve surgery using blood cardioplegia via 27 tertiary centres over 2 years. The primary combined endpoint will be cardiovascular death, non-fatal myocardial infarction, coronary revascularization and stroke at 1 year. Secondary endpoints will include peri-operative myocardial and acute kidney injury, intensive care unit and hospital stay, inotrope score, left ventricular ejection fraction, changes of quality of life and exercise tolerance. Patients will be randomized to receive after induction of anesthesia either RIC (4 cycles of 5 min inflation to 200 mmHg and 5 min deflation of a blood pressure cuff placed on the upper arm) or sham RIC (4 cycles of simulated inflations and deflations of the blood pressure cuff).

IMPLICATIONS

The findings from the ERICCA trial have the potential to demonstrate that RIC, a simple, non-invasive and virtually cost-free intervention, can improve clinical outcomes in higher-risk patients undergoing CABG ± valve surgery.

Remote-conditioning ischemia provides a potential approach to mitigate contrast medium-induced reduction in kidney function: a retrospective observational cohort study

Contrast medium administration during imaging and therapeutic procedures can cause renal injury, partly due to ischemia. Therefore, we hypothesized that brief ischemia and reperfusion episodes applied at a distant site - multiple balloon inflations and deflations during angioplasty - may serve as a remote-conditioning (RC) stimulus and thereby protect against contrast-induced kidney injury. To test this hypothesis, we (1) utilized cases from a prior study in which patients undergoing emergent angioplasty for ST segment elevation myocardial infarction received either 1-3 balloon inflations (controls) or were 'conditioned' with multiple (≥4) inflations, and (2) assessed renal function for 3 days in patients with an estimated glomerular filtration rate (eGFR) of <90 ml/min/1.73 m(2) prior to revascularization (mild kidney disease). Both groups displayed increased eGFR at day 1 after angioplasty versus baseline; attributed to in-hospital hydration (control: 77 ± 14 vs. 68 ± 12 ml/min/1.73 m(2); p < 0.01; RC: 81 ± 21 vs. 69 ± 12 ml/min/1.73 m(2); p < 0.01). In controls, this improvement was transient: eGFR subsequently decreased to 70 ± 14 ml/min/1.73 m(2) at day 3 (p < 0.05). In contrast, the RC group (despite receiving 25% more contrast volume) showed no functional decline at day 3 (80 ± 14 ml/min/1.73 m(2)). These results are consistent with remote ischemic conditioning providing a novel potential approach to attenuate contrast-associated renal injury.

Middle-term results of percutaneous coronary intervention with standard metallic stent “Ephesos II” implantation in patients with coronary heart disease

Aim. In a non-randomised study, to assess middle-term (9 months) effectiveness and safety of percutaneous coronary intervention (PCI) with “Ephesos II” stent implantation. Material and methods. The study included 41 patients, treated at the Sani Konukoglu Medical Centre, Gaziantep, Turkey. Results. Immediate angiography-confirmed PCI success was achieved in 100 % of the participants. Nine months after the intervention, the percentage of survived patients without restenosis and repeat revascularization was 77,6 %. Control angiography at 9 months was performed in 95,1 % of the patients. The mean in-stent late loss was 0,32±0,25. Restenosis was observed in 22,4 % of the subjects. In all cases of in-stent restenosis, successful repeat PCI was performed. At 9 months, the proportion of the survived patients without moderate to severe cardiac complications and events reached 70,3 %. Conclusion. This non-randomised study demonstrated good short and middle-term results of PCI with standard metallic stent “Ephesos II” implantation.

RISK and SAFE signaling pathway interactions in remote limb ischemic perconditioning in combination with local ischemic postconditioning

Local ischemic postconditioning (IPost) and remote ischemic perconditioning (RIPer) are promising methods to decrease ischemia-reperfusion (I/R) injury. We tested whether the use of the two procedures in combination led to an improvement in cardioprotection through a higher activation of survival signaling pathways. Rats exposed to myocardial I/R were allocated to one of the following four groups: Control, no intervention at myocardial reperfusion; IPost, three cycles of 10-s coronary artery occlusion followed by 10-s reperfusion applied at the onset of myocardial reperfusion; RIPer, 10-min limb ischemia followed by 10-min reperfusion initiated 20 min after coronary artery occlusion; IPost+RIPer, IPost and RIPer in combination. Infarct size was significantly reduced in both IPost and RIPer (34.25 ± 3.36 and 24.69 ± 6.02%, respectively) groups compared to Control (54.93 ± 6.46%, both p < 0.05). IPost+RIPer (infarct size = 18.04 ± 4.86%) was significantly more cardioprotective than IPost alone (p < 0.05). RISK pathway (Akt, ERK1/2, and GSK-3β) activation was enhanced in IPost, RIPer, and IPost+RIPer groups compared to Control. IPost+RIPer did not enhance RISK pathway activation as compared to IPost alone, but instead increased phospho-STAT-3 levels, highlighting the crucial role of the SAFE pathway. In IPost+RIPer, a SAFE inhibitor (AG490) abolished cardioprotection and blocked both Akt and GSK-3β phosphorylations, whereas RISK inhibitors (wortmannin or U0126) abolished cardioprotection and blocked STAT-3 phosphorylation. In our experimental model, the combination of IPost and RIPer improved cardioprotection through the recruitment of the SAFE pathway. Our findings also indicate that cross talk exists between the RISK and SAFE pathways.

Peri-procedural myocardial injury during percutaneous coronary intervention: an important target for cardioprotection

Percutaneous coronary intervention (PCI) has become the predominant procedure for coronary revascularization in patients with both stable and unstable coronary artery disease (CAD). Over the past two decades, technical advances in PCI have resulted in a better and safer therapeutic procedure with minimal procedural complications. However, about 30% of patients undergoing elective PCI sustain myocardial injury arising from the procedure itself, the extent of which is significant enough to carry prognostic importance. The peri-procedural injury which accompanies PCI might therefore reduce some of the beneficial effects of coronary revascularization. The availability of more sensitive serum biomarkers of myocardial injury such as creatine phosphokinase MB isoenzyme (CK-MB), Troponin T, and Troponin I has enabled the quantification of previously undetectable myocardial injury. Peri-procedural myocardial injury (PMI) can also be visualized by cardiac magnetic resonance imaging, a technique which allows the detection and quantification of myocardial necrosis following PCI. The identification of CAD patients at greatest risk of sustaining PMI during PCI would allow targeted treatment with novel therapies capable of limiting the extent of PMI or reducing the number of patients experiencing PMI.

Non-invasive limb ischemic pre-conditioning reduces oxidative stress and attenuates myocardium ischemia-reperfusion injury in diabetic rats

This study was to explore whether repeated non-invasive limb ischemic pre-conditioning (NLIP) can confer an equivalent cardioprotection against myocardial ischemia-reperfusion (I/R) injury in acute diabetic rats to the extent of conventional myocardial ischemic pre-conditioning (MIP) and whether or not the delayed protection of NLIP is mediated by reducing myocardial oxidative stress after ischemia-reperfusion. Streptozotocin-induced diabetic rats were randomized to four groups: Sham group, the I/R group, the MIP group and the NLIP group. Compared with the I/R group, both the NLIP and MIP groups showed an amelioration of ventricular arrhythmia, reduced myocardial infarct size, increased activities of total superoxide dismutase (SOD), manganese-SOD and glutathione peroxidase, increased expression of manganese-SOD mRNA and decreased xanthine oxidase activity and malondialdehyde concentration (All p < 0.05 vs I/R group). It is concluded that non-invasive limb ischemic pre-conditioning reduces oxidative stress and attenuates myocardium ischemia-reperfusion injury in diabetic rats.

Role of the autonomic nervous system in cardioprotection by remote preconditioning in isoflurane-anaesthetized dogs

AIMS

Remote ischaemic preconditioning (rIPC) protects cardiac and non-cardiac tissues against ischaemic injury. Although there is increased demand to investigate its potential clinical applicability, fundamental mechanisms responsible for rIPC-mediated protection remain unresolved. We examined in isoflurane-anaesthetized dogs whether an intact cardiac nervous system was necessary to mediate rIPC protection against ischaemic injury.

METHODS AND RESULTS

Dogs were randomly allocated to six groups: 1, control (CON, no-rIPC); 2, rIPC (4 × 5 min renal artery occlusion/reperfusion); 3, autonomic ganglionic blockade with hexamethonium (HEX, no-rIPC; 20 mg/kg iv); 4, HEX + rIPC; 5, cardiac decentralization by surgical ablation of extracardiac nerves (DCN, no-rIPC); and 6, DCN + rIPC. All dogs underwent 60 min coronary occlusion and 180 min reperfusion; cardiac haemodynamic parameters were monitored. Regional blood flow (microspheres) in the heart and kidneys was assessed. Necrotic tissue was visualized using triphenyltetrazolium staining and related to anatomic risk zone size (area at risk; P = NS between groups) and coronary collateral blood flow. Infarct size (% AAR) was 29 ± 5 (mean ± 1 SD) in CON and 15 ± 4 in rIPC dogs (P = 0.001 vs. CON); 24 ± 3 in HEX vs. 12 ± 2 in HEX + rIPC (P = 0.001 vs. HEX); and 20 ± 2 in DCN vs. 12 ± 4 in DCN + rIPC (P = 0.001 vs. DCN). In CON dogs, infarct size was inversely related to coronary collateral flow; this relation was shifted downwards in all groups pre-treated with rIPC.

CONCLUSION

We report robust myocardial protection by rIPC against ischaemic injury in canines that was not abrogated by either pharmacological or surgical decentralization of cardiac nerves.

Percutaneous closure of patent foramen ovale and atrial septal defect in adults: the impact of clinical variables and hospital procedure volume on in-hospital adverse events

BACKGROUND

Percutaneous closure of patent foramen ovale/atrial septal defect (PFO/ASD) is an increasingly common procedure perceived as having minimal risk. There are no population-based estimates of in-hospital adverse event rates of percutaneous PFO/ASD closure.

METHODS

We used nationally representative data from the 2001-2005 Nationwide Inpatient Sample to identify patients >or-=20 years old admitted to an acute care hospital with an International Classification of Diseases, Ninth Revision code designating percutaneous PFO/ASD closure on the first or second hospital day. Variables analyzed included age, sex, number of comorbidities, year, same-day use of intracardiac or other echocardiography, same-day left heart catheterization, hospital size and teaching status, PFO/ASD procedural volume, and coronary intervention volume. Outcomes of interest included length of stay, charges, and adverse events.

RESULTS

The study included 2,555 (weighted to United States population: 12,544 +/- 1,987) PFO/ASD closure procedures. Mean age was 52.0 +/- 0.4 years, and 57.3% +/- 1.0% were women. Annual hospital volume averaged 40.8 +/- 7.7 procedures (range, 1-114). Overall, 8.2 +/- 0.8% of admissions involved an adverse event. Older patients and those with comorbidities were more likely to sustain adverse events. Use of intracardiac echocardiography was associated with fewer adverse events. The risk of adverse events was inversely proportional to annual hospital volume (odds ratio [OR] 0.91, 95% confidence interval [CI] 0.86-0.96, per 10 procedures), even after limiting the analysis to hospitals performing >or=10 procedures annually (OR 0.91, 95% CI 0.85-0.98). Adverse events were more frequent at hospitals in the lowest volume quintile as compared with the highest volume quintile (13.3% vs 5.4%, OR 2.42, 95% CI 1.55-3.78).

CONCLUSIONS

The risk of adverse events of percutaneous PFO/ASD closure is inversely correlated with hospital volume. This relationship applies even to hospitals meeting the current guidelines, performing >or=10 procedures annually.

Protective ischaemia in patients: preconditioning and postconditioning

Infarct size can be limited by reducing the determinants of infarct size or increasing collateral blood flow by treatment initiated before the ischaemic event. Reperfusion is the definitive treatment for permanently reducing infarct size and restoring some degree of contractile function to the affected myocardium. Innate survival mechanisms in the heart can be stimulated by short, non-lethal periods of ischaemia and reperfusion, applied either before or after the ischaemic event. Preconditioning, a series of transient intervals of ischaemia and reperfusion applied before the lethal 'index' ischaemic event, sets in motion molecular and cellular mechanisms that increase cardiomyocyte survival to a degree that had not hitherto been seen before. The cardioprotective ischaemic-reperfusion protocol applied at onset of reperfusion, termed 'postconditioning' (Postcon), is also associated with significant cardioprotection that can be applied at the point of reperfusion treatment in the catheterization laboratory or operating room. Both preconditioning and Postcon have been successfully applied to the clinical setting and have been found to reduce infarct size and other attributes of post-ischaemic injury. This review will summarize the physiological preclinical data on preconditioning and Postcon that are relevant to their translation to clinical therapeutics and treatment.

Clinical cardioprotection and the value of conditioning responses

Adjunctive cardioprotective strategies for ameliorating the reversible and irreversible injuries with ischemia-reperfusion (I/R) are highly desirable. However, after decades of research, the promise of clinical cardioprotection from I/R injury remains poorly realized. This may arise from the challenges of trialing and effectively translating experimental findings from laboratory models to patients. One can additionally consider whether features of the more heavily focused upon candidates could limit or preclude therapeutic utility and thus whether we might shift attention to alternate strategies. The phenomena of preconditioning and postconditioning have proven fertile in identification of experimental means of cardioprotection and are the most intensely interrogated responses in the field. However, there is evidence these processes, which share common molecular signaling elements and end effectors, may be poor choices for clinical exploitation. This includes evidence of age dependence, limiting efficacy in target aged or senescent hearts; refractoriness to conditioning stimuli in diseased myocardium; interference from a variety of relevant pharmaceuticals; inadvertent induction of these responses by prior ischemia or commonly used drugs, precluding further benefit; and sex dependence of protective signaling. This review focuses on these features, raising questions about current research strategies, and the suitability of these widely studied phenomena as rational candidates for clinical translation.

Remote ischaemic preconditioning: underlying mechanisms and clinical application

Remote ischaemic preconditioning (RIPC) represents a strategy for harnessing the body's endogenous protective capabilities against the injury incurred by ischaemia and reperfusion. It describes the intriguing phenomenon in which transient non-lethal ischaemia and reperfusion of one organ or tissue confers resistance to a subsequent episode of lethal ischaemia reperfusion injury in a remote organ or tissue. In its original conception, it described intramyocardial protection, which could be relayed from the myocardium served by one coronary artery to another. It soon became apparent that myocardial infarct size could be dramatically reduced by applying brief ischaemia and reperfusion to an organ or tissue remote from the heart before the onset of myocardial infarction. The concept of remote organ protection has now been extended beyond that of solely protecting the heart to providing a general form of inter-organ protection against ischaemia-reperfusion injury. This article reviews the history and evolution of the phenomenon that is RIPC, the potential mechanistic pathways underlying its cardioprotective effect, and its emerging application in the clinical setting.

Cumulative funnel plots for the early detection of interoperator variation: retrospective database analysis of observed versus predicted results of percutaneous coronary intervention

OBJECTIVE

To use funnel plots and cumulative funnel plots to compare in-hospital outcome data for operators undertaking percutaneous coronary interventions with predicted results derived from a validated risk score to allow for early detection of variation in performance.

DESIGN

Analysis of prospectively collected data.

SETTING

Tertiary centre NHS hospital in the north east of England.

PARTICIPANTS

Five cardiologists carrying out percutaneous coronary interventions between January 2003 and December 2006.

MAIN OUTCOME MEASURES

In-hospital major adverse cardiovascular and cerebrovascular events (in-hospital death, Q wave myocardial infarction, emergency coronary artery bypass graft surgery, and cerebrovascular accident) analysed against the logistic north west quality improvement programme predicted risk, for each operator. Results are displayed as funnel plots summarising overall performance for each operator and cumulative funnel plots for an individual operator's performance on a case series basis.

RESULTS

The funnel plots for 5198 patients undergoing percutaneous coronary interventions showed an average observed rate for major adverse cardiovascular and cerebrovascular events of 1.96% overall. This was below the predicted risk of 2.06% by the logistic north west quality improvement programme risk score. Rates of in-hospital major adverse cardiovascular and cerebrovascular events for all operators were within the 3sigma upper control limit of 2.75% and 2sigma upper warning limit of 2.49%.

CONCLUSION

The overall in-hospital major adverse cardiovascular and cerebrovascular events rates were under the predicted event rate. In-hospital rates after percutaneous coronary intervention procedure can be monitored successfully using funnel and cumulative funnel plots with 3sigma control limits to display and publish each operator's outcomes. The upper warning limit (2sigma control limit) could be used for internal monitoring. The main advantage of these charts is their transparency, as they show observed and predicted events separately. By this approach individual operators can monitor their own performance, using the predicted risk for their patients but in a way that is compatible with benchmarking to colleagues, encapsulated by the funnel plot. This methodology is applicable regardless of variations in individual operator case volume and case mix.