Jack Andrews

Comparison of the Efficacy and Safety of Early Rule Out Pathways for Acute Myocardial Infarction

Background: High-sensitivity cardiac troponin assays enable myocardial infarction to be ruled out earlier, but the optimal approach is uncertain. We compared the European Society of Cardiology rule-out pathway with a pathway that incorporates lower cardiac troponin concentrations to risk stratify patients. Methods: Patients with suspected acute coronary syndrome (n=1218) underwent high-sensitivity cardiac troponin I measurement at presentation and 3 and 6 or 12 hours. We compared the European Society of Cardiology pathway (<99th centile at presentation or at 3 hours if symptoms <6 hours) with a pathway developed in the High-STEACS study (High-Sensitivity Troponin in the Evaluation of Patients With Acute Coronary Syndrome) population (<5 ng/L at presentation or change <3 ng/L and <99th centile at 3 hours). The primary outcome was a comparison of the negative predictive value of both pathways for index type 1 myocardial infarction or type 1 myocardial infarction or cardiac death at 30 days. We evaluated the primary outcome in prespecified subgroups stratified by age, sex, time of symptom onset, and known ischemic heart disease. Results: The primary outcome occurred in 15.7% (191 of 1218) patients. In those less than the 99th centile at presentation, the European Society of Cardiology pathway ruled out myocardial infarction in 28.1% (342 of 1218) and 78.9% (961 of 1218) at presentation and 3 hours, respectively, missing 18 index and two 30-day events (negative predictive value, 97.9%; 95% confidence interval, 96.9–98.7). The High-STEACS pathway ruled out 40.7% (496 of 1218) and 74.2% (904 of 1218) at presentation and 3 hours, missing 2 index and two 30-day events (negative predictive value, 99.5%; 95% confidence interval, 99.0–99.9; P<0.001 for comparison). The negative predictive value of the High-STEACS pathway was greater than the European Society of Cardiology pathway overall (P<0.001) and in all subgroups, including those presenting early or known to have ischemic heart disease. Conclusions: Use of the High-STEACS pathway incorporating low high-sensitivity cardiac troponin concentrations rules out myocardial infarction in more patients at presentation and misses 5-fold fewer index myocardial infarctions than guideline-approved pathways based exclusively on the 99th centile. Clinical Trial Registration: URL: http://clinicaltrials.gov. Unique identifier: NCT01852123.

New methods to image unstable atherosclerotic plaques

Atherosclerotic plaque rupture is the primary mechanism responsible for myocardial infarction and stroke, the top two killers worldwide. Despite being potentially fatal, the ubiquitous prevalence of atherosclerosis amongst the middle aged and elderly renders individual events relatively rare. This makes the accurate prediction of MI and stroke challenging. Advances in imaging techniques now allow detailed assessments of plaque morphology and disease activity. Both CT and MR can identify certain unstable plaque characteristics thought to be associated with an increased risk of rupture and events. PET imaging allows the activity of distinct pathological processes associated with atherosclerosis to be measured, differentiating patients with inactive and active disease states. Hybrid integration of PET with CT or MR now allows for an accurate assessment of not only plaque burden and morphology but plaque biology too. In this review, we discuss how these advanced imaging techniques hold promise in redefining our understanding of stable and unstable coronary artery disease beyond symptomatic status, and how they may refine patient risk-prediction and the rationing of expensive novel therapies.

Progressive breathlessness following transcatheter aortic valve replacement

An 84-year-old man presented urgently to the cardiology clinic with rapid onset exertional dyspnoea while walking on the flat. Five months previously, he underwent implantation of a balloon-expandable 26 mm transcatheter heart valve (SAPIEN 3, Edwards Lifesciences) for severe aortic stenosis. On clinical examination, the jugular venous pressure was elevated and a mid-late ejection systolic murmur was audible in the aortic region. ECG demonstrated sinus rhythm with a left ventricular (LV) strain pattern. Transthoracic echocardiography and cardiac CT were performed (figure 1). Figure 1 (A) Transthoracic continuous wave Doppler through the transcatheter AV. ECG-gated cardiac CT oblique reconstruction of the LV outflow tract and aortic root in mid-diastole (B) with axial reconstruction of the transcatheter AV in end-systole (inset). AT, acceleration time; AV, aortic valve; LV, left ventricular. Question Which aetiology best explains this presentation? Pannus formation Transcatheter bioprosthetic valve endocarditis Patient-prosthesis mismatch Transcatheter bioprosthetic valve leaflet thrombosis Structural valve degeneration

18 18F-flouride pet MR in valvular and coronary heart disease; a pilot investigational study

Introduction Recently, PET-MR has emerged as a novel imaging technique capable of assessing myocardial disease, inflammation and microcalcification. We aimed to investigate aortic valve and coronary 18F-NaF activity in subjects with aortic stenosis (AS) and coronary disease. Methods 25 patients underwent 18F-NaF PET-MR scanning. PET data was acquired in list mode with a standard Dixon attenuation correction technique. MR angiography was performed following infusion of Gadolinium. PET activity was quantified by calculating standardised uptake values (SUV) and tissue to background ratios (TBR) on fused PET-MR images. Culprit arteries were identified during preceding invasive coronary angiography. Results 22 of 25 patients completed the protocol. Patients with aortic stenosis had higher aortic valve SUVmax and TBRmax (Valve SUV max/left atrial SUV mean) than those without (SUVmax 1.89±0.60 vs 1.15±0.38, p=0.001 and TBRmax 2.87±0.98 vs 1.77±0.43, p=0.001). 13/13 patients with MI had focal 18F-NaF uptake in the culprit vessel with an SUV max and TBR max greater than the proximal referent vessel (SUV max 1.05±0.26 vs 0.74±0.13, p=0.002 and TBRmax 1.64±0.47 vs 1.16±0.26, p=0.004). Conclusion Similar to previous 18F-NaF PET CT studies, 18F-NaF PET-MR uptake is significantly greater in those with confirmed AS than those without. 18F-NaF uptake also accurately identifies culprit arteries in those with recent MI. The results share similarities with recently published valvular and coronary 18F-NaF PET-CT studies and thus promote further research into the utility of cardiovascular PET-MR as a complementary hybrid imaging technique.

Early detection of valvular calcification

The early stages of the formation of calcific nodules in the aortic valve can be detected by two-photon excited fluorescence microscopy.

IS IT SAFE TO USE HIGH-SENSITIVITY CARDIAC TROPONIN T TO RULE OUT MYOCARDIAL INFARCTION AT PRESENTATION?

Background: Whilst the majority of patients with chest pain presenting to the Emergency Department do not have myocardial infarction (MI), most are admitted for serial cardiac troponin testing. High-sensitivity cardiac troponin assays may improve the risk stratification of patients at presentation

47-year-old female with an apical mass

Clinical introduction A 47-year-old female with no medical history presented with a sudden collapse. Physical examination, chest X-ray and high-sensitivity cardiac troponin I were normal, however ECG demonstrated anterior T-wave inversion. CT pulmonary angiography was performed which ruled out pulmonary embolism but revealed a non-calcified, homogenous mass at the left ventricular (LV) apex. It was not clear whether this mass was intramyocardial or pericardial. Transthoracic echocardiography confirmed the apical mass but was unable to establish its aetiology. Subsequent cardiac MR (CMR) demonstrated a highly vascular intramyocardial mass on perfusion imaging (Figure 1A, online supplementary video A), with striking, homogenous late gadolinium enhancement (Figure 1B) consistent with a diagnosis of cardiac fibroma.1 The patient underwent successful surgical excision of the mass (see online supplementary image A) and made a good symptomatic recovery, quickly mobilising around the ward. On examination, the patient was afebrile but had a blood pressure of 90/40 mm Hg and raised venous pressure. Postoperative imaging with echocardiography (see online supplementary video B) and CMR (Figure 1C, D and online supplementary video C) revealed some unexpected findings. Study the provided images. Figure 1 (A) Preoperative cardiac MR (CMR) perfusion. (B) Preoperative late gadolinium enhancement

Endocarditis and monocular blindness

A man aged 77 years with postrenal transplant lymphoproliferative disease was admitted with high fever, elevated inflammatory markers and a heart murmur. Blood cultures grew Enterococcus faecalis and he was found to have mitral valve endocarditis on echocardiogram and subsequently started on appropriate antibiotics. 5 days into treatment, he developed ocular symptoms and 3 days later, he had irreversible monocular visual loss. He was seen by the ophthalmology team who diagnosed endogenous endopthalmitis secondary to bacteraemic spread from his endocarditis. Despite treatment with intravitreal antibiotics and prolonged systemic antibiotics, his sight did not recover. Although septic emboli are common in endocarditis, endogenous endophthalmitis is rarely reported and frequently results in visual loss. Early treatment confers an improved prognosis.