Impact of early (<24h) versus delayed (>24h) intervention in patients with non ST segment elevation myocardial infarction (an observational study of 20882 patients)

Background

In patients presenting with non ST-segment elevation acute coronary syndromes (NSTE-ACS) an invasive approach has been shown to be superior to conservative management.

Purpose

We aimed to investigate the optimal timing of invasive coronary angiography and subsequent intervention.

Methods

We examined the impact ofearly (≤24h) versus delayed (>24h) intervention in a large observational cohort of 20882 consecutive patients with acute NSTE myocardial infarction (NSTEMI) treated with PCI between 2005 and 2015 at 9 tertiary cardiac centers in London (UK) using Cox-regression analysis and propensity matching.

Results

Mean age was 64.5±12.7 years and 26.1% were females. A quarter (27.6%), were treated within 24h.Patients treated within 24h were slightly younger (62.8±12.8 vs. 65.2±12.6, p<0.001), most commonly male (76% vs. 72.9%, p<0.001) and were more frequently ventilated (2.3% vs. 1.4%, p<0.001) and in cardiogenic shock (3.6% vs. 1.4%, p<0.001) with dynamic changes on their ECG (84.5% vs. 76.1% p<0.001). At a median follow up of 4.2 years (interquartile range 1.8 to 7) 17.7% of patients had died. Estimated 5-year survival in patients treated within 24h was 84.6% vs. 81% for those treated >24h following their presentation (p<0.001). This survival benefit remained following adjustment for confounders; HR (delayed vs. early management)1.11 (95% CI 1.003 to 1.23, p=0.046). In the propensity matched cohort of 4356 patients in each group, there remained a trend for higher survival in the early intervention group (p=0.061).

Conclusions

Notwithstanding the limitations of the retrospective design, this real-world cohort of NSTEMI patients suggests that an early intervention (≤24h) may improve mid term survival.

Figure 1

Funding Acknowledgement

Type of funding source: None

Patient consent in emergency cardiovascular medicine: lessons from the ARREST trial in out-of-hospital cardiac arrest

Introduction

Randomised trials in emergency cardiovascular medicine are challenging but vital for improving patient care. Obtaining informed consent in such an environment is a particular issue and can be controversial. The ARREST trial is assessing whether out-of-hospital cardiac arrest patients without an obvious cause should be taken to a specialist heart centre or the closest emergency department in London, UK. This patient group presents specific difficulties: patients lack capacity to consent, presentation is unpredictable, care must not be delayed, and mortality rates can be >50%.

Purpose

Within existing consent and methodological frameworks we aimed to design a randomised clinical trial to pragmatically, safely and ethically recruit cardiac arrest patients pre-hospital.

Methods

During the set-up of ARREST we accessed the following sources of information: 1) ARREST research team; 2) cardiovascular patient groups; 3) researchers running similar trials; 4) regulatory bodies; and, 5) published literature on research in emergency contexts. The information that we collected guided the design of the trial with a focus on patient consent, documentation and follow-up.

Results

The ARREST trial uses deferred consent with remote online randomisation to enrol patients without delaying care. To minimise the risk of bias, baseline and primary endpoint data are collected on patients who die or are discharged prior to consent. Remote follow-up using electronic health records reduces the burden on the patients and researchers. Full ethical approval was received in January 2018 and the first patient was enrolled in February 2018. ARREST is recruiting to target and is on track to finish within the projected timelines.

Conclusions

Deferred consent has been key to the success of ARREST and patients have been receptive. However, further research into the experience of patients in emergency cardiovascular medicine trials using deferred consent is needed to better understand when it is an appropriate model. More broadly, there is a shortfall in high quality research in challenging environments such as emergency cardiovascular care. Innovation in consent methods and proportional research governance would facilitate higher quality research and benefit patient care.

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): British Heart Foundation

Mitral regurgitation in acute heart failure: prevalence and response to treatment

 

Heart failure (HF) affects an estimated 90 000 people within the UK. As a consequence of ventricular remodelling, mitral regurgitation (MR) is common in patients with HF, further contributing to poor prognosis, frequent hospitalisation, and higher rates of mortality. Conventional treatment options include medical therapy, cardiac resynchronisation and conventional mitral valve surgery, with transcatheter mitral valve repair (TMVR) reserved for symptomatic patients with left ventricular dysfunction and multiple comorbidities, considered high surgical risk.

Aim

Our objectives were to determine: (1) the proportion of patients with an acute HF admission, ejection fraction (EF) of <50% and moderate or more MR; (2) the effectiveness of optimal medical therapy (OMT) in reducing the severity of MR and symptoms; (3) the number of patients with moderate or more MR, EF <50% and symptoms despite OMT.

Method

We performed a retrospective analysis of patients who presented with acute HF to two large tertiary centres over a five-year period. Based on a combination of electronic care records, and national registry and mortality data, we determined baseline symptoms, symptom progression, and co-morbidities. Echocardiography data was used to assess the degree of MR and EF. Where patients underwent a subsequent echocardiogram on OMT, the change in the degree of MR, EF and symptoms (NYHA class) was examined.

Results

Over a five-year period (Jan 2012–Dec 2017), 1884 patients presented with acute HF. Of this cohort, 302 (16%) had moderate or more MR and EF of <50%. Mortality amongst patients with moderate or more MR was 29.9% at one year (compared to 26.9% for those with less than moderate MR, p=0.058). Of this cohort, 45% had sufficient clinical and echocardiographic paired follow up data to enable assessment of the effects of OMT (Age 78±20.78; Male n=76 (56.3%). This analysis showed, despite OMT, all 135 patients still had moderate or more MR. When compared with previous echocardiography data, 11 (8%) patients showed a reduction in the severity of MR which meant 92% (124) of patient with MR either saw no improvement or worsening of their MR severity. Of those with severe MR, 23% (7) demonstrated an improvement in the degree of MR following OMT. Clinically 70 (51.4%) patients had an improvement in symptoms. There was significant improvement in the NYHA class pre and post optimisation of medical therapy (p<0.001) across all grades of MR. Despite OMT, 124 (92%) patients with moderate or more MR and EF <50% remained symptomatic.

Conclusions

A large portion of patients who present with acute HF have moderate or more MR. Although medical therapy is effective in providing some relief from symptoms, the large majority of patients continue to have moderate or more MR. We propose a portion of these patients are potential candidates for TMVR, and should be considered for further intervention.

Funding Acknowledgement

Type of funding source: None

P6516The association between prior coronary artery bypass graft surgery and outcome after percutaneous coronary intervention (PCI): an observational study of 123,780 patients

Background

Limited information exists regarding procedural success and clinical outcomes in patients with previous CABG undergoing percutaneous coronary intervention (PCI). We sought to compare outcomes in patients undergoing PCI with or without previous coronary artery bypass grafts (CABG).

Methods

This was an observational cohort study of 123,780 consecutive PCI procedures from the Pan-London (United Kingdom) PCI registry, from January 2005 to December 2015. The primary end-point was all-cause mortality at a median follow-up of 3.0 years (interquartile range 1.2–4.6 years).

Results

12,641 (10.2%) patients had a history of previous CABG, of whom 29.3% (n=3,703) underwent PCI to native vessels and 70.7% (n=8,938) to bypass grafts. There were significant differences in the demographic, clinical, and procedural characteristics of these groups. The risk of mortality during follow-up was significantly higher in patients with prior CABG (23.2%) (p=0.0005) compared to patients with no history of prior CABG (12.1%) and was seen for patients who underwent either native vessel (20.1%) or bypass graft PCI (24.2%, p<0.0001). However, after adjustment for baseline characteristics, there was no significant difference in outcomes seen between the groups when PCI was performed in native vessels in patients with previous CABG (HR 1.02, 95% CI 0.77–1.34; P=0.89) but a significant increase in mortality among patients with PCI to bypass grafts (HR 1.33 95% CI 1.03–1.71, P=0.026). This was seen after multivariate adjustment and propensity matching.

Figure 1. Kaplan-Meier Curves

Conclusion

Patients with prior CABG are older, with a greater comorbid burden and more complex procedural characteristics, but after adjustment for these differences clinical outcomes are similar to patients undergoing PCI without prior CABG. In these patients, native vessel PCI was associated with better outcomes compared to the treatment of vein grafts.

3326Infective endocarditis after transcatheter aortic valve implantation: findings from a UK nationwide linkage study

Introduction

Infective endocarditis (IE) is a potentially fatal complication of prosthetic valve replacement and increasing use of transcatheter aortic valve implantation (TAVI) has resulted in a new elderly and frail population at increased risk of IE. The incidence of IE after TAVI and factors that influence the risk and subsequent outcome are relatively unknown.

Purpose

To describe the incidence, predictors, echocardiographic findings, microbiology and clinical outcomes of IE following TAVI in the United Kingdom (UK).

Methods

Patients who underwent TAVI between Jan 1 2007 and Dec 31 2016 were identified from the UK TAVI database held by the National Institute for Cardiovascular Outcomes Research. For this cohort, all hospital admissions with a primary diagnosis of IE were identified by linkage with the NHS Hospital Episode Statistics Admitted Patient Care database, or by contact with regional TAVI centres. Additional information concerning clinical presentation, imaging findings, microbiology, management and patient outcome were obtained where possible from the treating physician.

Results

A total of 16,014 patients underwent TAVI, of whom 157 developed IE over a median follow-up of 23.8 (IQR 7.8–52.4) months - an overall incidence of 0.98% (0.53% at one year post-TAVI). The mean age of patients with IE was 79.2±7.8 years, and 69% were male. The median time to IE following TAVI was 10.0 (IQR 4.0–22.3) months.

On multivariate analysis, IE was significantly more common in men (HR 2.05, 95% CI 1.35–3.11, p=0.001) and in patients receiving mechanically-expandable (HR 2.15, 95% CI 1.16–4.01, p=0.015) or balloon-expandable valves (HR 1.60, 95% CI 1.01–2.52, p=0.045) compared to self-expanding valves. IE was also more common in those with an aortic valve peak gradient following TAVI deployment greater than median (HR 1.81, 95% CI 1.23–2.67, p=0.003).

The most common presenting symptom was fever (present in 67.1%). The most frequent causal organisms were enterococci (25.9%), followed by oral streptococci (16.4%) and Staphylococcus aureus (11.8%). Transoesophageal echocardiography demonstrated vegetations in 72.5% of patients, most commonly on the TAVI valve leaflets (58.8%). Only 8.24% of patients underwent surgical valve intervention.

Survival rates at hospital discharge and one year follow up were 61.4% and 54.4%, respectively. Specific factors associated with one-year mortality were cardiogenic shock (HR 4.6, 95% CI 2.1–10.3, p=0.0002), septic shock (HR 3.4, 95% CI 1.4–8.3, p=0.006) and stroke (HR 4.9, 95% CI 1.46–16.7, p=0.01).

Conclusions

The incidence of IE one year after TAVI was 0.53% and greater risk was associated with male sex, mechanically-expandable and balloon-expandable valves, and elevated post-deployment valve gradient. Enterococci were the most common causative organism. Overall survival at one year was 54.4%, with adverse outcome predicted by cardiogenic shock, septic shock or stroke.

P6484Invasive and non-invasive characterisation of low gradient aortic stenosis

Background

Low gradient severe aortic stenosis (LGAS) is associated with unfavourable outcomes when compared to high gradient aortic stenosis (HGAS), yet the contributing pathophysiology is poorly understood.

Methods

Symptomatic LGAS and HGAS patients undergoing trans-catheter aortic valve implantation (TAVI) underwent 3T stress perfusion cardiac magnetic resonance imaging (CMR) pre-(within 24 hours) and post-(4–6 months) TAVI. Left ventricular (LV) contractility and coronary flow/pressure were measured during hyperaemia and rapid pacing, immediately before and after TAVI, using a conductance LV catheter and dual-pressure and Doppler sensor–tipped guidewire in the mid-left anterior descending coronary artery.

Results

24 patients were recruited resulting in 19 suitable datasets (LGAS N=9, HGAS N=10, equally matched for comorbidities and B-natriuretic peptide level). LGAS patients had a smaller LV end diastolic volume index (p=0.035) and lower LV mass index (LVMI) (p=0.037). Pre-TAVI stress global endocardium-epicardium gradient was 0.88±0.09 and global myocardial perfusion reserve (MPR) 2.0±0.48 in 14 patients (6 LGAS and 8 HGAS patients, no difference between groups). Pre-TAVI, baseline coronary data demonstrated lower augmentation pressure (AP, p=0.035) and augmentation index (AIx, p=0.02) in the LGAS group. LGAS patients also exhibited a shorter ejection time (p=0.015), larger forward compression waves during rest, hyperaemia and rapid pacing, and smaller backward expansion waves (BEW) (p=0.001). Lower baseline end systolic pressure (p=0.004), inotropy (dP/dt+, p=0.045), lusitropy (dP/dt-, p=0.069), and stroke work (p=0.019) were observed in the LGAS group. Whilst LV size was smaller the LGAS group, rapid pacing induced a more significant drop in end systolic volume (p=0.045) and ejection fraction (p=0.015) in patients with HGAS. Post-TAVI, the hyperaemic BEW fell sharply (p<0.001), along with coronary VTI (p=0.02), and average pulse velocity (p=0.028), and AP and AIx remained lower (p=0.034 and p=0.031, respectively). The forward expansion wave was reduced in LGAS during rapid pacing. The HGAS group displayed a more profound drop in dP/dt+ (p=0.011) and dP/dt- p=0.014) at rest following intervention. Repeat CMR demonstrated statistically significant reduction in LV size and LVMI (p=0.012 and p<0.001, respectively) with significant increase in 3D global peak radial, circumferential and longitudinal strain (p=0.004, p=0.001 and p=0.018, respectively). Post-TAVI stress global endocardium-epicardium gradient was 0.88±0.13 and MPR 2.46±0.59 (improved from pre-TAVI, p=0.05). There was no difference in remodelling patterns or perfusion between the two groups.

Conclusion

This is the first study detailing the combined invasive and CMR pathophysiological changes in LGAS. Despite invasive parameters indicating a disease of less severe AS, the level of perfusion abnormality is disproportionate which may in part, relate to their adverse prognosis.

Acknowledgement/Funding

This research is funded by a Clinical Research Training Fellowship grant from the British Heart Foundation (FS/16/51/32365).

Timing and mode of intervention for patients with left sided valvular heart disease: an individualized approach

Left sided valvular heart disease poses major impact on life and lifestyle. Medical therapy merely palliates chronic severe valve disease and once symptoms or haemodynamic sequelae appear, life expectancy is markedly truncated. In this article, we review the mechanisms of valve pathology, latest evidence in the quest for pharmacological options, means by which to predict deterioration, and standard and novel treatment options.

Adjuncts to transcatheter aortic valve implantation

INTRODUCTION

The appreciable rise in percutaneous valve procedures has been pursued by a wave of development in advanced technology to help guide straightforward, streamlined and safe intervention. This review article aims to highlight the adjunctive devices, tools and techniques currently used in transcatheter aortic valve implantation procedures to avoid potential pitfalls. Areas covered: The software and devices featured here are at the forefront of technological advances, most of which are not yet in widespread use. These products have been discussed in national and international structural intervention conferences and the authors felt it important to showcase particularly well designed adjuncts that improve procedural efficacy and safety. Whilst vascular pre-closure systems are used routinely and are an integral part of these complex cardiovascular procedures, these have been well summarised elsewhere and are beyond the scope of this article. Expert commentary: The rising volume of patients with aortic stenosis who are treatable with TAVI means that this exponential increase in procedures must be accompanied by a steady decline in procedural complications. This section provides an overview of our current perspective, and what we feel the direction of travel will be.

Impact of preprocedural mitral regurgitation upon mortality after transcatheter aortic valve implantation (TAVI) for severe aortic stenosis

Objective

To identify the effects of preprocedural significant mitral regurgitation (MR) and change in MR severity upon mortality after transcatheter aortic valve implantation (TAVI) using the Edwards SAPIEN system.

Methods

A retrospective analysis of 316 consecutive patients undergoing TAVI for aortic stenosis at a single centre in the UK between March 2008 and January 2013. Patients were stratified into two groups according to severity of MR: ≥grade 3 were classed as significant and ≤grade 2 were non-significant. Change in MR severity was assessed by comparison of baseline and 30-day echocardiograms.

Results

60 patients had significant MR prior to TAVI (19.0%). These patients were of higher perioperative risk (logistic EuroScore 28.7±16.6% vs 20.3±10.7%, p=0.004) and were more dyspnoeic (New York Heart Association class IV 20.0% vs 7.4%, p=0.014). Patients with significant preprocedural MR displayed greater 12-month and cumulative mortality (28.3% vs 20.2%, log-rank p=0.024). Significant MR was independently associated with mortality (HR 4.94 (95% CI 2.07 to 11.8), p<0.001). Of the 60 patients with significant MR only 47.1% had grade 3–4 MR at 30 days (p<0.001). Patients in whom MR improved had lower mortality than those in whom it deteriorated (log-rank p=0.05).

Conclusions

Significant MR is frequently seen in patients undergoing TAVI and is independently associated with increased all-cause mortality. Yet almost half also exhibit significant improvements in MR severity. Those who improve have better outcomes, and future work could focus upon identifying factors independently associated with such an improvement.

Detection of intracoronary thrombus by magnetic resonance imaging in patients with acute myocardial infarction

BACKGROUND

Persistent intracoronary thrombus after plaque rupture is associated with an increased risk of subsequent myocardial infarction and mortality. Coronary thrombus is usually visualized invasively by x-ray coronary angiography. Non-contrast-enhanced T1-weighted magnetic resonance (MR) imaging has been useful for direct imaging of carotid thrombus and intraplaque hemorrhage by taking advantage of the short T1 of methemoglobin present in acute thrombus and intraplaque hemorrhage. The aim of this study was to investigate the use of non-contrast-enhanced MR for direct thrombus imaging (MRDTI) in patients with acute myocardial infarction.

METHODS AND RESULTS

Eighteen patients (14 men; age, 61±9 years) underwent MRDTI within 24 to 72 hours of presenting with an acute coronary syndrome before invasive x-ray coronary angiography; MRDTI was performed with a T1-weighted, 3-dimensional, inversion-recovery black-blood gradient-echo sequence without contrast administration. Ten patients were found to have intracoronary thrombus on x-ray coronary angiography (left anterior descending, 4; left circumflex, 2; right coronary artery, 4; and right coronary artery-posterior descending artery, 1), and 8 had no visible thrombus. We found that MRDTI correctly identified thrombus in 9 of 10 patients (sensitivity, 91%; posterior descending artery thrombus not detected) and correctly classified the control group in 7 of 8 patients without thrombus formation (specificity, 88%). The contrast-to-noise ratio was significantly greater in coronary segments containing thrombus (n=10) compared with those without visible thrombus (n=131; mean contrast-to-noise ratio, 15.9 versus 2.6; P<0.001).

CONCLUSION

Use of MRDTI allows selective visualization of coronary thrombus in a patient population with a high probability of intracoronary thrombosis.

Vortex formation and recirculation zones in left anterior descending artery stenoses: computational fluid dynamics analysis

Flow patterns may affect the potential of thrombus formation following plaque rupture. Computational fluid dynamics (CFD) were employed to assess hemodynamic conditions, and particularly flow recirculation and vortex formation in reconstructed arterial models associated with ST-elevation myocardial infraction (STEMI) or stable coronary stenosis (SCS) in the left anterior descending coronary artery (LAD). Results indicate that in the arterial models associated with STEMI, a 50% diameter stenosis immediately before or after a bifurcation creates a recirculation zone and vortex formation at the orifice of the bifurcation branch, for most of the cardiac cycle, thus allowing the creation of stagnating flow. These flow patterns are not seen in the SCS model with an identical stenosis. Post-stenotic recirculation in the presence of a 90% stenosis was evident at both the STEMI and SCS models. The presence of 90% diameter stenosis resulted in flow reduction in the LAD of 51.5% and 35.9% in the STEMI models and 37.6% in the SCS model, for a 10 mmHg pressure drop. CFD simulations in a reconstructed model of stenotic LAD segments indicate that specific anatomic characteristics create zones of vortices and flow recirculation that promote thrombus formation and potentially myocardial infarction.

Does a well developed collateral circulation predispose to restenosis after percutaneous coronary intervention? An intravascular ultrasound study

OBJECTIVE

To evaluate whether a well developed collateral circulation predisposes to restenosis after percutaneous coronary intervention (PCI).

DESIGN

Prospective observational study.

PATIENTS AND SETTING

58 patients undergoing elective single vessel PCI in a tertiary referral interventional cardiac unit in the UK.

METHODS

Collateral flow index (CFI) was calculated as (Pw-Pv)/(Pa-Pv), where Pa, Pw, and Pv are aortic, coronary wedge, and right atrial pressures during maximum hyperaemia. Collateral supply was considered poor (CFI < 0.25) or good (CFI > or = 0.25).

MAIN OUTCOME MEASURES

In-stent restenosis six months after PCI, classified as neointimal volume > or = 25% stent volume on intravascular ultrasound (IVUS), or minimum lumen area < or = 50% stent area on IVUS, or minimum lumen diameter < or = 50% reference vessel diameter on quantitative coronary angiography.

RESULTS

Patients with good collaterals had more severe coronary stenoses at baseline (90 (11)% v 75 (16)%, p < 0.001). Restenosis rates were similar in poor and good collateral groups (35% v 43%, p = 0.76 for diameter restenosis, 27% v 45%, p = 0.34 for area restenosis, and 23% v 24%, p = 0.84 for volumetric restenosis). CFI was not correlated with diameter, area, or volumetric restenosis (r2 < 0.1 for each). By multivariate analysis, stent diameter, stent length, > 10% residual stenosis, and smoking history were predictive of restenosis.

CONCLUSION

A well developed collateral circulation does not predict an increased risk of restenosis after PCI.

Improving pain management: breaking down the invisible barrier

There is compelling evidence that despite growing research into the complex neurophysiology of pain, the development of acute pain services, increasing educational interest in pain management and the proliferation of literature, many patients continue to suffer from unrelieved acute pain while in hospital. Educational efforts to bring about a change in practice have been relatively unsuccessful or slow to have real impact. Although it is still recognized that poor knowledge of pain control by all healthcare professionals is the major barrier to improving pain management, contemporary studies show that other, more subtle barriers can just as effectively inhibit a timely and effective response to patients' reports of pain. These barriers are not just the ones created by poor knowledge, myth and misconception; the most powerful barriers to change may be the invisible institutional barriers that can be entrenched within hospital policies and nursing rituals.