The everolimus eluting Synergy MegatronTM drug-eluting stent platform: Early outcomes from the European Synergy MegatronTM Implanters' Registry.

BACKGROUND: The Synergy MegatronTM is an everolimus-drug eluting stent that may offer advantages in the treatment of aorto-ostial disease and large proximal vessels. AIMS: To report the short- to medium-term clinical outcomes from the European Synergy MegatronTM Implanters' Registry. METHODS: This registry was an investigator-initiated study conducted at 14 European centers. The primary outcome was target lesion failure (TLF), defined as the composite of cardiovascular death, target vessel myocardial infarction (MI), and target lesion revascularisation. RESULTS: Five hundred seventy-five patients underwent PCI with MegatronTM between 2019 and 2021. Patients were 69 ± 12 years old, 26% had diabetes mellitus, 24% had moderate-severe left ventricular impairment and 59% presented with an acute coronary syndrome. 15% were deemed prohibitively high risk for surgical revascularisation. The target vessel involved the left main stem in 55%, the ostium of the RCA in 13% and was a true bifurcation (Medina 1,1,1) in 50%.  At 1 year, TLF was observed in 40 patients, with 26 (65%) occurring within the first 30 days. The cumulative incidence of TLF was 4.5% at 30 days and 8.6% (95% CI 6.3-11.7) at 1 year. The incidence of stent thrombosis was 0.5% with no late stent thromboses. By multivariate analysis, the strongest independent predictors of TLF were severe left ventricular impairment (HR 3.43, 95% CI: 1.67-6.76, p < 0.001) and a target vessel involving the left main (HR 4.00 95% CI 1.81-10.15 p = 0.001). CONCLUSIONS: Use of the Synergy MegatronTM everolimus eluting stent in a 'real-world' setting shows favorable outcomes at 30 days and 1 year.

Rethinking False Positive Exercise Electrocardiographic Stress Tests by Assessing Coronary Microvascular Function.

BACKGROUND: Exercise electrocardiographic stress testing (EST) has historically been validated against the demonstration of obstructive coronary artery disease. However, myocardial ischemia can occur because of coronary microvascular dysfunction (CMD) in the absence of obstructive coronary artery disease. OBJECTIVES: The aim of this study was to assess the specificity of EST to detect an ischemic substrate against the reference standard of coronary endothelium-independent and endothelium-dependent microvascular function in patients with angina with nonobstructive coronary arteries (ANOCA). METHODS: Patients with ANOCA underwent invasive coronary physiological assessment using adenosine and acetylcholine. CMD was defined as impaired endothelium-independent and/or endothelium-dependent function. EST was performed using a standard Bruce treadmill protocol, with ischemia defined as the appearance of ≥0.1-mV ST-segment depression 80 ms from the J-point on electrocardiography. The study was powered to detect specificity of ≥91%. RESULTS: A total of 102 patients were enrolled (65% women, mean age 60 ± 8 years). Thirty-two patients developed ischemia (ischemic group) during EST, whereas 70 patients did not (nonischemic group); both groups were phenotypically similar. Ischemia during EST was 100% specific for CMD. Acetylcholine flow reserve was the strongest predictor of ischemia during exercise. Using endothelium-independent and endothelium-dependent microvascular dysfunction as the reference standard, the false positive rate of EST dropped to 0%. CONCLUSIONS: In patients with ANOCA, ischemia on EST was highly specific of an underlying ischemic substrate. These findings challenge the traditional belief that EST has a high false positive rate.

Impact of Anatomical and Viability-guided Completeness of Revascularization on Clinical Outcomes in Ischemic Cardiomyopathy.

BACKGROUND: Complete revascularization of coronary disease has been linked to improved outcomes in patients with preserved left ventricular (LV) function. OBJECTIVES: To identify the impact of complete revascularization in patients with severe LV dysfunction. METHODS: Patients enrolled in the REVIVED-BCIS2 trial were eligible if baseline/procedural angiograms and viability studies were available for analysis by independent core laboratories. Anatomical and viability-guided completeness of revascularization were measured by the coronary and myocardial revascularization indices (RIcoro and RImyo) respectively, where RIcoro=[change in BCIS Jeopardy Score (BCIS-JS)] / [baseline BCIS-JS] and RImyo=[number of revascularized viable segments] / [ number of viable segments supplied by diseased vessels]. The PCI group was classified as having complete or incomplete revascularization by median RIcoro and RImyo. The primary outcome was death or hospitalization for heart failure. RESULTS: Of 700 randomized patients, 670 were included. The baseline BCIS-JS and SYNTAX scores were 8 (6 to 10) and 22 (15 to 29) respectively. In those assigned to PCI, median RIcoro and RImyo values were 67% and 85%. Compared to the group assigned to optimal medical therapy alone, there was no difference in the likelihood of the primary outcome in those receiving complete anatomical or viability-guided revascularization (HR 0.90, 95% CI 0.62-1.32 and HR 0.95, 95% CI 0.66-1.35 respectively). A sensitivity analysis by residual SYNTAX score showed no association with outcome. CONCLUSIONS: In patients with severe left ventricular dysfunction, neither complete anatomical nor viability-guided revascularization were associated with improved event-free survival compared to incomplete revascularization or treatment with medical therapy alone.

Revascularisation for Ischaemic Cardiomyopathy.

Coronary artery disease is a leading cause of heart failure with reduced ejection fraction. Coronary artery bypass grafting appears to provide clinical benefits such as improvements in quality of life, reductions in readmissions and MI, and favourable effects on long-term mortality; however, there is a significant short-term procedural risk when left ventricular function is severely impaired, which poses a conundrum for many patients. Could percutaneous coronary intervention provide the same benefits without the hazard of surgery? There have been no randomised studies to support this practice until recently. The REVIVED-BCIS2 trial (NCT01920048) assessed the outcomes of percutaneous coronary intervention in addition to optimal medical therapy in patients with ischaemic left ventricular dysfunction and stable coronary artery disease. This review examines the trial results in detail, suggests a pathway for investigation and revascularisation in ischaemic cardiomyopathy, and explores some of the remaining unanswered questions.

The Impact of a Dedicated Chronic Total Occlusion PCI Program on Heart Team Decision Making.

BACKGROUND: Guidelines endorse a heart team (HT) approach to standardize the decision-making process for patients with complex coronary artery disease (CAD). With percutaneous treatment options for complex CAD increasing, we hypothesized that practice had changed over the past decade-and that more individuals, previously deemed too high risk for intervention, would now be referred for either surgical or percutaneous revascularization. METHODS: This observational study was conducted at St Thomas' Hospital (London, United Kingdom). All patients discussed at HT meetings were recorded and treatment recommendations audited. A subset of historic cases was selected for blinded, repeat discussion. RESULTS: From April 2018 to 2019, a total of 52 HT meetings discussing 375 cases were held. Patients tended to be male, with a majority demonstrating multivessel CAD in the context of preserved left ventricular function. SYNTAX scores were balanced across the tertiles. Thirty-five percent of patients had at least 1 chronic total occlusion (mean J-CTO, 3 [interquartile range, 2-3]), affecting the right coronary artery in 60%. Fifteen historic patients with isolated CTOs were re-presented an average of 8 years later; only 3 patients received the same outcome, with 80% now receiving a recommendation for revascularization over medical therapy. CONCLUSIONS: A dedicated program supporting complex coronary intervention is associated with a change in treatment recommendations issued by the local HT. In line with international guidelines, this might indicate that any complex or multivessel CAD should be discussed at HT meetings with, ideally, the presence of CTO operators.

FLOWER-MI and the root of the problem with non-culprit revascularisation.

How do we reduce cardiac death and myocardial infarction by percutaneous coronary intervention (PCI) in coronary heart disease? Although the interventional community continues to grapple with this question in stable angina, the benefits of PCI for non-culprit lesions found at ST-elevation myocardial infarction are established. Is it then wishful thinking that an index developed in stable coronary disease, for identifying lesions capable of causing ischaemia will show an incremental benefit over angiographically guided non-culprit PCI? This is the question posed by the recently published FLOW Evaluation to Guide Revascularization in Multi-vessel ST-elevation Myocardial Infarction (FLOWER-MI) trial. We examine the trial design and results; ask if there is any relationship between the baseline physiological significance of a non-culprit lesion and vulnerability to future myocardial infarction; and consider if more sophisticated methods can help guide or defer non-culprit revascularisation.

Cardiac arrest, chronic total occlusion, and occluded stent in a 16-year-old boy with Kawasaki disease: a case report.

BACKGROUND: Kawasaki disease is the leading cause of premature coronary artery disease in developed countries. As such, patients may require revascularisation as children. However, there are no randomized data guiding treatment so this must be individualized. This case report describes the decision-making in a young patient requiring revascularization who had already suffered stent occlusion. CASE SUMMARY: Our patient, a 16-year-old boy with Kawasaki disease, presented with cardiac arrest during exercise. Coronary angiography showed that a proximal left anterior descending artery stent implanted at the age of 8 years had occluded some time ago and his right coronary artery was also chronically occluded. He has discussed in several Heart Team meetings and with international colleagues and a consensus reached to revascularize him surgically. DISCUSSION: It is vital that young patients with complex coronary disease are discussed in an extensive multidisciplinary setting to determine the most suitable means of treatment. The previously occluded stent was crucial in the individualized decision-making in this patient.

Respiration driven excessive sinus tachycardia treated with clonidine.

A 26-year-old man presented to our syncope service with debilitating daily palpitations, shortness of breath, presyncope and syncope following a severe viral respiratory illness 4 years previously. Mobitz type II block had previously been identified, leading to a permanent pacemaker and no further episodes of frank syncope. Transthoracic echocardiography, electophysiological study and repeated urine metanepherines were normal. His palpitations and presyncope were reproducible on deep inspiration, coughing, isometric hand exercise and passive leg raises. We demonstrated rapid increases in heart rate with no change in morphology on his 12 lead ECG. His symptoms were resistant to fludrocortisone, flecainide, ß blockers and ivabradine. Initiation of clonidine in combination with ivabradine led to rapid resolution of his symptoms. We suggest that an excessive respiratory sinus arrhythmia was responsible for his symptoms and achieved an excellent response with the centrally acting sympatholytic clonidine, where previous peripherally acting treatments had failed.

A systematic approach to designing reliable VV optimization methodology: assessment of internal validity of echocardiographic, electrocardiographic and haemodynamic optimization of cardiac resynchronization therapy.

BACKGROUND: In atrial fibrillation (AF), VV optimization of biventricular pacemakers can be examined in isolation. We used this approach to evaluate internal validity of three VV optimization methods by three criteria. METHODS AND RESULTS: Twenty patients (16 men, age 75 ± 7) in AF were optimized, at two paced heart rates, by LVOT VTI (flow), non-invasive arterial pressure, and ECG (minimizing QRS duration). Each optimization method was evaluated for: singularity (unique peak of function), reproducibility of optimum, and biological plausibility of the distribution of optima. The reproducibility (standard deviation of the difference, SDD) of the optimal VV delay was 10 ms for pressure, versus 8 ms (p=ns) for QRS and 34 ms (p<0.01) for flow. Singularity of optimum was 85% for pressure, 63% for ECG and 45% for flow (Chi(2)=10.9, p<0.005). The distribution of pressure optima was biologically plausible, with 80% LV pre-excited (p=0.007). The distributions of ECG (55% LV pre-excitation) and flow (45% LV pre-excitation) optima were no different to random (p=ns). The pressure-derived optimal VV delay is unaffected by the paced rate: SDD between slow and fast heart rate is 9 ms, no different from the reproducibility SDD at both heart rates. CONCLUSIONS: Using non-invasive arterial pressure, VV delay optimization by parabolic fitting is achievable with good precision, satisfying all 3 criteria of internal validity. VV optimum is unaffected by heart rate. Neither QRS minimization nor LVOT VTI satisfy all validity criteria, and therefore seem weaker candidate modalities for VV optimization. AF, unlinking interventricular from atrioventricular delay, uniquely exposes resynchronization concepts to experimental scrutiny.