Acute limb ischaemia due to vasospasm: a rare presentation

A 30-year-old woman with active intravenous drug use presented with pain, blue discolouration, paresthesia and lack of grip strength of left hand for 1 week. Physical examination revealed blue discolouration, decreased sensation and cold to touch in the left hand. She had no palpable radial pulse. She admitted Heroin use only but the urine drug screen was also positive for amphetamine. CT angiogram of the left upper extremity was concerning for acute ischaemia due to arterial occlusion. The initial plan was for amputation. However, to salvage the limb with thrombolysis, an interventional radiology angiogram was performed. The angiogram demonstrated diffuse arterial spasm and response to nitroglycerin. She was treated with nitroglycerin drip and transitioned to a calcium channel blocker. She did improve significantly. To ensure no embolic sequelae, the patient was discharged with a month of oral anticoagulation.

Acute lower extremity ischaemia after surgical interventricular communication closure in a newborn

We report a 5-month-old infant who developed an unexpected acute ischaemia of the right lower limb following a surgical perimembranous interventricular communication closure. This rare case of ischaemia was due to an occlusive right common iliac artery dissection. It was early managed by angioplasty with two ABSORB® bioresorbable stents, resulted in complete revascularisation of the right leg.

Abstract P405: Cardioprotective Actions Of Nitroxyl Donor Angeli's Salt Are Preserved In The Diabetic Heart And Vasculature In The Face Of Nitric Oxide Resistance

Introduction: The risk of fatal cardiovascular events is increased in patients with type 2 diabetes mellitus (T2DM). A major contributor to poor prognosis is impaired nitric oxide (NO•) signalling at the level of tissue responsiveness, termed NO• resistance. Nitroxyl (HNO) induces positive inotropic and lusitropic effects in healthy and failing hearts. Hypothesis: We hypothesised that in a rodent model, T2DM will promote, and HNO will circumvent, NO• resistance in the myocardium and coronary vasculature. Methods: At 8 weeks of age, male Sprague-Dawley rats commenced a high-fat diet. After two weeks, the rats received low-dose streptozotocin (two intraperitoneal injections, 35 mg/kg, over two consecutive days), and continued the diet. Twelve weeks later, hearts were Langendorff-perfused to assess responses to the NO• donor diethylamine NONOate (DEA/NO) and the HNO donor Angeli’s salt. Results: Inotropic, lusitropic and coronary vasodilator responses to DEA/NO were impaired, and responses to Angeli’s salt were preserved or enhanced, in T2DM hearts compared with non-diabetic hearts. Conclusions: This is the first evidence that inotropic and lusitropic responses are preserved, and NO• resistance in the coronary vasculature is circumvented, by the HNO donor Angeli’s salt in T2DM. These findings highlight the cardiovascular therapeutic potential of HNO donors, especially in cardiac emergencies such as acute ischaemia or heart failure. Figure 1. Dose-response curves and maximal responses to DEA/NO or Angeli's salt in diabetic or non-diabetic hearts. (A-C) LV+dP/dt, (D-F) LV-dP/dt and (G-I) coronary flow rate. Data expressed as change from baseline (denoted by Δ), mean ± SEM. Data analysed by two-way RM ANOVA with Sidak's post-hoc test. *P<0.05 vs. non-diabetic. LV, left ventricular; LV+dP/dt, maximal rate of rise in LV pressure; LV-dP/dt, maximal rate of fall in LV pressure.

Complex case of COVID-19 and infective endocarditis

A 50-year-old man with no medical history of note presented with new onset of confusion and dyspnoea. He tested positive for coronavirus (COVID-19), and subsequently, was admitted to the intensive care unit due to severe sepsis and acute renal failure requiring haemodialysis. Shortly afterwards, he was intubated due to haemodynamic instability. His blood culture was positive for Staphylococcus aureus bacteraemia, and echocardiogram showed evidence of vegetation in the aortic valve area. He was commenced on intravenous antibiotics for infective endocarditis (IE). Following extubation, he underwent an MRI of the spine due to increasing back pain. This was suggestive of L5–S1 discitis, likely secondary to septic emboli from IE. A few days later, he developed acute ischaemia of the left toes and extensive thrombosis of the right cubital and left iliac veins. Following a prolonged hospital admission, he was discharged home and later underwent an elective forefoot amputation from which he made a good recovery.

Electrophysiological and anatomical factors determine arrhythmic risk in acute myocardial ischaemia and its modulation by sodium current availability

Acute myocardial ischaemia caused by coronary artery disease is one of the main causes of sudden cardiac death. Even though sodium current blockers are used as anti-arrhythmic drugs, decreased sodium current availability, also caused by mutations, has been shown to increase arrhythmic risk in ischaemic patients. The mechanisms are still unclear. Our goal is to exploit perfect control and data transparency of over 300 high-performance computing simulations to investigate arrhythmia mechanisms in acute myocardial ischaemia with variable sodium current availability. The human anatomically based torso-biventricular electrophysiological model used includes representation of realistic ventricular anatomy and fibre architecture, as well as ionic to electrocardiographic properties. Simulations show that reduced sodium current availability increased arrhythmic risk in acute regional ischaemia due to both electrophysiological (increased dispersion of refractoriness across the ischaemic border zone) and anatomical factors (conduction block from the thin right ventricle to thick left ventricle). The asymmetric ventricular anatomy caused high arrhythmic risk specifically for ectopic stimuli originating from the right ventricle and ventricular base. Increased sodium current availability was ineffective in reducing arrhythmic risk for septo-basal ectopic excitation. Human-based multiscale modelling and simulations reveal key electrophysiological and anatomical factors determining arrhythmic risk in acute ischaemia with variable sodium current availability.

Black blood vessel wall MRI to identify vulnerable atherosclerotic plaque in a non-stenotic intracranial vertebral artery as a cause of acute ischaemia

Conventional neuroimaging techniques for investigating the cause of stroke are mainly centred on investigating luminal stenosis. The pathophysiology of intracranial atherosclerotic disease (ICAD) and stroke is complex and extends beyond just vessel narrowing. The concept of the vulnerable atherosclerotic plaque, that can result in acute coronary syndromes, has been well described in the cardiac literature 1,2 although this concept is less well accepted among stroke physicians. We describe a case of a 61-year-old male with acute neurological sequelae from a non-stenotic atherosclerotic plaque of the intracranial vertebral artery. This case report describes the additional use of vessel wall MRI techniques to aid the radiologist in identifying such vulnerable lesions and therefore helping to tailor management and prevent further clinical deterioration.

Caloric restriction mimetics for the treatment of cardiovascular diseases

Caloric restriction mimetics (CRMs) are emerging as potential therapeutic agents for the treatment of cardiovascular diseases. CRMs include natural and synthetic compounds able to inhibit protein acetyltransferases, to interfere with acetyl coenzyme A biosynthesis, or to activate (de)acetyltransferase proteins. These modifications mimic the effects of caloric restriction, which is associated with the activation of autophagy. Previous evidence demonstrated the ability of CRMs to ameliorate cardiac function and reduce cardiac hypertrophy and maladaptive remodelling in animal models of ageing, mechanical overload, chronic myocardial ischaemia, and in genetic and metabolic cardiomyopathies. In addition, CRMs were found to reduce acute ischaemia–reperfusion injury. In many cases, these beneficial effects of CRMs appeared to be mediated by autophagy activation. In the present review, we discuss the relevant literature about the role of different CRMs in animal models of cardiac diseases, emphasizing the molecular mechanisms underlying the beneficial effects of these compounds and their potential future clinical application.

Brain imaging abnormalities and outcome after acute ischaemic stroke: the ENCHANTED trial

ObjectiveTo test the hypothesis that imaging signs of ‘brain frailty’ and acute ischaemia predict clinical outcomes and symptomatic intracranial haemorrhage (sICH) after thrombolysis for acute ischaemic stroke (AIS) in the alteplase dose arm of ENhanced Control of Hypertension ANd Thrombolysis strokE stuDy (ENCHANTED).MethodsBlinded assessors coded baseline images for acute ischaemic signs (presence, extent, swelling and attenuation of acute lesions; and hyperattenuated arteries) and pre-existing changes (atrophy, leucoaraiosis and old ischaemic lesions). Logistic regression models assessed associations between imaging features and death at 7 and 90 days; good recovery (modified Rankin Scale scores 0–2 at 90 days) and sICH. Data are reported with adjusted ORs and 95% CIs.Results2916 patients (67±13 years, National Institutes of Health Stroke Scale 8 (5–14)) were included. Visible ischaemic lesions, severe hypoattenuation, large ischaemic lesion, swelling and hyperattenuated arteries were associated with 7-day death (OR (95% CI): 1.52 (1.06 to 2.18); 1.51 (1.01 to 2.18); 2.67 (1.52 to 4.71); 1.49 (1.03 to 2.14) and 2.17 (1.48 to 3.18)) and inversely with good outcome. Severe atrophy was inversely associated with 7-day death (0.52 (0.29 to 0.96)). Atrophy (1.52 (1.08 to 2.15)) and severe leucoaraiosis (1.74 (1.20 to 2.54)) were associated with 90-day death. Hyperattenuated arteries were associated with sICH (1.71 (1.01 to 2.89)). No imaging features modified the effect of alteplase dose.ConclusionsNon-expert-defined brain imaging signs of brain frailty and acute ischaemia contribute to the prognosis of thrombolysis-treated AIS patients for sICH and mortality. However, these imaging features showed no interaction with alteplase dose.