Cardiac stereotactic ablative radiotherapy for control of refractory ventricular tachycardia: initial UK multicentre experience.

BACKGROUND: Options for patients with ventricular tachycardia (VT) refractory to antiarrhythmic drugs and/or catheter ablation remain limited. Stereotactic radiotherapy has been described as a novel treatment option. METHODS: Seven patients with recurrent refractory VT, deemed high risk for either first time or redo invasive catheter ablation, were treated across three UK centres with non-invasive cardiac stereotactic ablative radiotherapy (SABR). Prior catheter ablation data and non-invasive mapping were combined with cross-sectional imaging to generate radiotherapy plans with aim to deliver a single 25 Gy treatment. Shared planning and treatment guidelines and prospective peer review were used. RESULTS: Acute suppression of VT was seen in all seven patients. For five patients with at least 6 months follow-up, overall reduction in VT burden was 85%. No high-grade radiotherapy treatment-related side effects were documented. Three deaths (two early, one late) occurred due to heart failure. CONCLUSIONS: Cardiac SABR showed reasonable VT suppression in a high-risk population where conventional treatment had failed.

A Novel Quadripolar Active Fixation Left-Ventricular Pacing Lead for Cardiac Resynchronization Therapy: Initial United Kingdom Experience.

OBJECTIVES: This study sought to assess immediate and short-term performance of the Medtronic Attain Stability Quadripolar 4798 lead (Medtronic, Dublin, Ireland). BACKGROUND: Cardiac resynchronization therapy (CRT) is an established treatment for appropriately selected patients with left ventricular (LV) systolic dysfunction. The most common reason for failure to implant a lead is the lack of a suitable epicardial vein, due either to an absent vessel in the target site, an unacceptably high threshold, lead instability, phrenic nerve stimulation, or a combination of reasons. In August 2017, a novel quadripolar active fixation LV lead (Medtronic) was released. This paper reports the initial clinical experience with lead implantation and specifically immediate and short-term pacing parameters across 3 United Kingdom centers. METHODS: Consecutive patients eligible for CRT were deemed suitable for this lead. Immediate and short-term lead performance data regarding LV threshold, impedance, and displacement rates were collected at standard pacing checks (1 day, 5 weeks, 3 months, and 9 months post-implantation). RESULTS: CRT using this lead was attempted in 82 cases and was successful in 81 cases (98.8%). LV thresholds and impedance levels were 1.22 ± 0.75 V and 737 ± 319 Ω at implantation; 1.16 ± 0.71 V and 597 ± 218 Ω at day 1; 1.02 ± 0.48 V and 579 ± 148 Ω at week 6; 0.98 ± 0.49 V and 569 ± 133 Ω at 3 months; and 1.06 ± 0.48 V and 570 ± 140 Ω at 9 months. As of the publication of this paper, no LV lead has been displaced. CONCLUSIONS: CRT using the Medtronic lead was successful in more than 98% of the patients. Short-to-medium-term data regarding lead performance and stability were excellent, with zero displacements as of the publication of this paper.

The use of a single chamber leadless pacemaker for the treatment of cardioinhibitory vasovagal syncope.

BACKGROUND: The use of pacemakers in the treatment of cardioinhibitory vasovagal syncope is controversial with a mixed message from the limited evidence base. Single chamber leadless pacemakers have been shown to be an effective alternative option to conventional pacemakers. OBJECTIVE: This study examines the use of leadless pacemakers in a cardioinhibitory vasovagal population in the United Kingdom. METHODS: Observational data on 32 patients implanted with the Micra Transcatheter Pacemaker System for vasovagal syncope are presented. Data was collected on implant indications, implant procedure and follow up data from 12 centres across the United Kingdom that had elected to use a Micra leadless pacemaker in this patient population. RESULTS: 32 patients aged 37 ±â€¯14 years (range 18 to 64 years) with 62% of the patients being female were recruited to the study. Vasovagal syncope was diagnosed clinically and with the support of Holter monitoring, tilt table testing and implantable loop recorders. The duration of symptoms was 8 ±â€¯8 yrs. with an average frequency of syncope being 4 ±â€¯6 times/year. The Micra pacemaker was successfully implanted in all patients with a major complication rate of 3.1%. Patients were followed up for 404 ±â€¯237 days (range 63-928 days). At follow up 28 (87%) patients were free from symptoms. CONCLUSIONS: This observational study suggests that the use of a single chamber leadless pacemaker in the treatment of cardioinhibitory vasovagal syncope might be a reasonable clinical option.

The 7-year teesside experience of primary prevention ICD indications following primary PCI (PPCI) and the potential impact of a change in NICE guidance.

INTRODUCTION: The recovery of LV function in patients with severe LV impairment in the acute phase following primary percutaneous coronary intervention (PPCI) is not well established. The indication for a primary prevention ICD post-STEMI is dependent on which screening guidance, NICE or ESC, is followed. The potential impact of the new NICE guidance is estimated. METHODS: We performed a retrospective analysis of all patients presenting with a STEMI over a 7-year period (2005-2012) treated with PPCI to determine in-hospital mortality, LV function at index presentation, at 3 months and the predicted primary prevention ICD implantation rate using NICE (TA095) and ESC 2006 guidelines. Predicted implant rates using the new NICE guidance (TA314) and actual implantation rates were also assessed. RESULTS: 3902 patients with a mean age of 65±13 years underwent PPCI. Of those patients surviving until discharge, 332 (10%) had LVEF ≤35%. 254 of 332 patients (76%) with a severely impaired ventricle were followed up at participating centres. 210 of 254 (83%) patients had a repeat echocardiogram within 3 months post-MI; among these patients, 89 (42%) remained to have LVEF ≤35%. The number of patients fulfilling NICE and ESC criteria for primary prevention ICD implantation was 14 (16%) and 84 (94%), respectively. The actual number of patients receiving an ICD was 17 (19%). The number of patients fulfilling the new NICE (TA314) guidance was 84 (94%). CONCLUSIONS: A small proportion of patients with STEMIs undergoing PPCI have a severely impaired LV systolic function. A large proportion of these patients will have improved LV systolic function at 3 months. There is a five-fold difference in the predicted ICD implantation rates depending on which guidance is followed-NICE versus ESC. The potential impact of the new NICE (TA314) guidance on ICD implantation will be a significant increase in ICD implantation rates.

Secondary prevention following coronary artery bypass grafting has improved but remains sub-optimal: the need for targeted follow-up.

A focused review of secondary preventive medication following revascularisation provides an opportunity to ensure optimal use of these agents. A retrospective analysis of our in-house cardiothoracic surgical database was performed to identify patients undergoing non-emergency, elective surgical revascularisation discharged on four secondary preventive medications: aspirin; beta-blockers; ACE-inhibitors and statins. Of 2749 patients studied, 2302 underwent isolated coronary artery bypass grafting (CABG), mean age 65.5 years (S.D. 9.15). Overall, 2536 (92%) patients were prescribed aspirin. Beta-blockers were prescribed in 2171 (79%) patients overall, in 1096/1360 (81%) of patients with a history of myocardial infarction and in 465/619 (75%) of patients with left ventricular systolic dysfunction (LVSD). Overall, 1518 (55%) patients were prescribed an ACE-inhibitor and 179 (6.5%) an angiotensin receptor blocker (ARB); one of these agents was prescribed in 446/619 (72%) patients with LVSD and 915/1360 (67%) patients with a history of previous myocardial infarction. Overall, 2518 (92%) patients were prescribed a statin. Secondary preventive therapies are prescribed more commonly on discharge after CABG than in previous studies, but there is a continuing under-utilisation of ACE-inhibitors. To maximise the potential benefits of these agents, further study is required to understand why they are not prescribed.

Meta-analysis of valve hemodynamics and left ventricular mass regression for stentless versus stented aortic valves.

BACKGROUND: Stentless aortic bioprostheses have been advocated as being superior to conventional bioprosthetic valves, with benefits including superior left ventricular mass regression and larger effective orifice area. Several high-quality randomized studies now exist on this topic, and we sought to summarize them by meta-analysis. METHODS: The literature was searched from 1995 to 2006, in MEDLINE, EMBASE, CRISP, metaRegister of Controlled Trials, and the Cochrane database. Experts were also contacted and reference lists searched. Studies were combined using the inverse variance fixed-effects model. Heterogeneity was assessed and a sensitivity analysis performed. Publication bias was also investigated. RESULTS: Ten studies were identified that included 919 patients in which the Freedom (Sorin Biomedica Cardio, Via Crescentino, Italy), Freestyle (Medtronic, Minneapolis, MN), Prima Plus (Edwards Life Sciences, Irvine, CA) and the Toronto and Biocor (St Jude Medical, St. Paul, MN) valves were used. The mean aortic valve gradient was lower in the stentless groups, with a weighted mean difference (WMD) of -3.57 mm Hg (95% confidence interval [CI], -4.36 to -2.78; p < 0.01). The left ventricular mass index was significantly lower in the stentless groups at 6 months (WMD, -6.42; 95% CI, -11.63 to -1.21; p = 0.02), but this improvement disappeared after 12 months (WMD, 1.19; 95% CI, -4.15 to 6.53; p = 0.66). The weighted mean increase in cross-clamp time was 23 minutes, and the increase in bypass time was 29 minutes with a stentless valve. CONCLUSIONS: This meta-analysis showed that stentless aortic valves provide an improved level of left ventricular mass regression at 6 months, reduced aortic gradients, and an improved effective orifice area index, at the expense of a 23-minute longer cross-clamp time and a 29-minute longer bypass time.

Should patients in cardiogenic shock undergo rescue angioplasty after failed fibrinolysis: comparison of primary versus rescue angioplasty in cardiogenic shock patients.

BACKGROUND: Trials of rescue angioplasty (rPCI) following failed fibrinolysis have excluded patients with cardiogenic shock and the benefit of rPCI in this setting is unknown. We compared the clinical, angiographic characteristics, 30-day and 1-year outcomes of cardiogenic shock patients undergoing rPCI with those undergoing primary percutaneous coronary intervention (PPCI). METHODS: Of the 171 patients undergoing PCI for cardiogenic shock between 1994 and 2005 at our institution, the indication was for PPCI in 65 and rPCI in 59 patients. Clinical, procedural, 30- day and 1-year mortality data were compared. RESULTS: There were no differences between the cohorts with regard to clinical and pre-PCI angiographic variables, except that patients who underwent rPCI were more likely to be interhospital transfers (64% vs. 43%; p = 0.02) and had a longer door-to-balloon time (median 298 [IQR 395 to 180] minutes in the rPCI group vs. 131 [IQR 215 to 90] minutes in the PPCI group; p <0.01). Glycoprotein IIb/IIIa inhibitors were used less often (20% vs. 42%; p = 0.01), but use of stents was similar in both groups. Patients undergoing rPCI had a lower rate of final TIMI 3 flow grade (56% vs. 74%; p = 0.04) and a higher 1-year mortality (71% vs. 49%; p = 0.01). In the patients with final TIMI flow 3, 1-year mortality was higher in the rPCI group (61% vs. 37%; p = 0.04). In patients with successful procedures (survived procedure, no emergency CABG, TIMI 3 flow), 1-year mortality was higher in the rPCI group (59% vs. 33%; p = 0.02). One-year mortality was 85% in both groups if the procedure was unsuccessful. One-year mortality in patients >70 years old with cardiogenic shock undergoing rPCI was 100% (n = 15) and 70% (n = 14) with PPCI. Rescue angioplasty, anterior myocardial infarction, multivessel disease and postprocedure TIMI flow grade <3 were found to be independent predictors of mortality at 30 days. CONCLUSIONS: In the setting of cardiogenic shock, rPCI patients were treated later than those undergoing PPCI. They had a lower final TIMI 3 flow and higher 1-year mortality. Even patients with a successful rPCI procedure had a higher 1-year mortality than those with a successful PPCI. Rescue angioplasty in the setting of cardiogenic shock was found be an independent predictor of mortality. Rescue angioplasty in elderly patients in cardiogenic shock (>75 years) may be a futile treatment. Efforts should be made to improve reperfusion and survival in these patients, possibly by either adopting PPCI for all patients presenting with ST-elevation acute myocardial infarction or, if this is not logistically possible, adopting PPCI for selected high-risk patients or early referral for rPCI in high-risk groups receiving fibrinolysis.

Early invasive versus conservative treatment in patients with failed fibrinolysis--no late survival benefit: the final analysis of the Middlesbrough Early Revascularisation to Limit Infarction (MERLIN) randomized trial.

BACKGROUND: Early (30 days) and midterm (6 months) clinical outcomes in trials comparing rescue angioplasty (rescue percutaneous coronary intervention [rPCI]) with conservative treatment of failed fibrinolysis complicating ST-segment elevation myocardial infarction have shown variable results. Whether early rPCI confers late (up to 3 years) clinical benefits is not known. METHODS: The MERLIN trial compared rPCI and a conservative strategy in patients with failed fibrinolysis complicating ST-segment elevation myocardial infarction. Three hundred seven patients with electrocardiographic evidence of failure to reperfuse at 60 minutes were included. Patients in cardiogenic shock were excluded. Thirty-day and 1-year results have been reported. Results of 3 years of follow-up are presented. RESULTS: Three-year mortality in the conservative arm and rPCI, respectively, was 16.9% versus 17.6% (P = .9, relative difference [RD] -0.8, 95% CI [-9.3 to 7.8]). Death rates were similar (3.9% vs 3.2%) between 1- and 3-year follow-up, respectively. The incidence of the composite secondary end point of death, reinfarction, stroke, unplanned revascularization, or heart failure was significantly higher in the conservative arm (64.3% vs 49%, P = .01, RD 15.3, 95% CI [4.2-26]). There was no significant difference in the rate of reinfarction (0.7% vs 0.7%) or heart failure (1.3% vs 2.7%) between 1 and 3 years between the conservative and rPCI arms, respectively. The incidence of subsequent unplanned revascularization at 3 years was significantly higher in the conservative arm (33.8% vs 14.4%, P < .01, RD 19.4, 95% CI [10-28.7]), most of which occurred within 1 year; the rates between 1 and 3 years were 3.9% in the conservative arm versus 2% in the rPCI arm. There was a trend toward fewer strokes in the conservative arm at 3 years (conservative arm 2.6% vs rPCI 6.5%, P = .1, RD -3.9%, 95% CI [-9.4 to 0.8]), with similar stroke rates (1.3% vs 1.3%) between 1- and 3-year follow-up. CONCLUSIONS: Rescue angioplasty did not confer a late survival advantage at 3 years. The composite end point occurred less often in the rPCI arm mainly because of fewer unplanned revascularization procedures in the early phase of follow-up. The highest risk of clinical events in patients with failed reperfusion is in the first year, beyond which the rate of clinical events is low.

Meta-analysis of randomized trials comparing anti-embolic devices with standard PCI for improving myocardial reperfusion in patients with acute myocardial infarction.

BACKGROUND: Failure to achieve adequate myocardial reperfusion often occurs during PCI in patients with STEMI. This is in part due to atheromatous and thrombotic distal embolization. Several anti-embolic devices have been developed to protect against distal embolization during percutaneous coronary interventions (PCI) to improve myocardial reperfusion and enhance event free survival. Evidence from current studies has not shown a consistent benefit, but anti-embolic devices continue to be used. METHODS: We conducted a systemic overview (meta-analysis) of randomized trials of thrombectomy or distal protection devices versus standard PCI to evaluate the effects of reducing distal embolization during PCI for native vessel acute myocardial infarction (AMI). We identified randomized trials by searching PubMed, OVID, the Cochrane databases, references of articles, and abstracts of conference proceedings (all from September 2000 to October 2005). Each trial tested the hypothesis that anti-embolic therapy would result in better clinical or angiographic results than standard PCI alone. RESULTS: Fourteen trials (n = 2630) were identified comparing a distal protection device or a thrombectomy device (n = 1320) versus standard PCI (n = 1310). When the studies were combined, primary endpoints of death or reinfarction were not improved by the use of anti-embolic devices (4% [52/1309] vs. 4.5% [59/1303], odds ratio [OR] 0.82 [95% CI 0.55 to 1.24, P= 0.35]). In subgroup analysis, analyzing the class of device separately, use of thrombectomy devices (4.4% [33/758 vs. 4.2% [32/763], OR 0.98 CI 0.53 to 1.83, P = 0.95]), and the use of distal protection device 3.5% [19/551] vs. 5% [27/540], OR 0.68 CI 0.37 to 1.23, P = 0.20]) during PCI for native vessel AMI did not improve the clinical outcome of death or reinfarction. The secondary endpoints of death, reinfarction, and major adverse cardiac events did not improve with the use of anti-embolic devices. CONCLUSION: The combined experience from randomized trials suggests that the use of anti-embolic devices does not decrease early mortality or reinfarction during PCI for native vessel AMI. Whether their use improves longer term outcomes is unknown. Further research is needed to clarify the indication and optimal devices for anti-embolic protection.

Should clopidogrel be stopped prior to urgent cardiac surgery?

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was whether clopidogrel should be stopped prior to urgent cardiac surgery. Altogether 143 papers were identified using the below mentioned search and all major international guidelines were included. Fourteen presented the best evidence to answer the clinical question. The author, journal, date and country of publication, patient group, relevant outcomes and weaknesses were tabulated. We conclude that there are two issues to address when considering this topic. Firstly, whether recent clopidogrel administration causes an increase in blood loss during cardiac surgery, and secondly, whether there is a risk to the patient of withholding clopidogrel and delaying surgery. In answer to the first issue, a meta-analysis of 11 cohort studies and also many additional papers have clearly shown recent clopidogrel administration within 5-7 days of surgery is associated with an increased chest drainage of 30-100%, an increase in blood product usage, and a 2-5 times increase in the need for re-exploration. In answer to the second issue, data from the major trials that provide the basis for the current era of clopidogrel therapy also suggest that witholding clopidogrel prior to a revascularization procedure is associated with a 1% increase in the risk of myocardial infarction. Despite this small increased risk, The American College of Cardiology recommend witholding clopidogrel for 5-7 days when clinically feasible.

Should high risk patients receive clopidogrel as well as aspirin post coronary arterial bypass grafting?

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was whether clopidogrel should be given in addition to aspirin in high risk patients after coronary bypass surgery to reduce thrombotic complications. High risk patients would include patients recently post MI or patients with a patent stent in situ. Altogether 511 papers were identified using the below mentioned search and all major international guidelines were included. Eleven presented the best evidence to answer the clinical question. The author, journal, date and country of publication, patient group, relevant outcomes and weaknesses were tabulated. The 2004 American College of Chest Physicians (ACCP) guidelines recommend 9-12 months of clopidogrel in addition to aspirin for patients undergoing coronary arterial bypass grafting (CABG) for non-ST segment elevation acute coronary syndrome (grade 1C). This is based on subanalyses of the CURE and CAPRIE studies that showed significant reductions in the incidence of death, myocardial infarction and stroke in patients who had CABG during these trials. A randomised trial is currently underway to investigate this further. Thus, patients post CABG who have had a recent NSTEMI or have a stent not covered by a graft should have clopidogrel in addition to aspirin for 9-12 months.