Myocardial infarction with non-obstructive coronary arteries (MINOCA) complicating myocarditis

Myocarditis can lead to myocardial infarction in the absence of coronary artery obstruction. We report a case of probable myocarditis, complicated by myocardial infarction with non-obstructive coronary arteries. A 19-year-old man presented with chest pain typical of myocarditis. He was a smoker but was otherwise well. Electrocardiogram revealed diffuse ST-elevation and echocardiography revealed a thin, akinetic apex. Troponin-T levels on admission were raised leading to an initial diagnosis of myocarditis being made. However, late gadolinium enhancement study on cardiac magnetic resonance imaging demonstrated transmural enhancement typical of ischaemia. Coronary angiogram was normal, leading to a likely diagnosis of myocardial infarction with non-obstructive coronary arteries. It is important to highlight that coronary assessment remains important when working up for myocarditis, as myocardial infarction with non-obstructive coronary arteries can often complicate myocarditis in cases of normal angiography. Another important lesson was on how cardiac magnetic resonance imaging provided vital evidence to support underlying ischaemia despite normal coronary angiogram, leading to a diagnosis of myocardial infarction with non-obstructive coronary arteries. Myocardial infarction with non-obstructive coronary arteries remains a broad 'umbrella' term and cardiac magnetic resonance imaging, as well as more invasive coronary imaging techniques during angiography, can further assist in its diagnosis. Our case provides a reminder that myocardial infarction with non-obstructive coronary arteries, although increasingly recognised, remains under-diagnosed and can often overlap with peri-myocarditis, highlighting the need to employ multi-modality imaging in guiding management.Copyright © The Author(s) 2021.

Coronary Microvascular Dysfunction and Prior Covid-19 Infection: Do Variants Matter?

Background Prior Coronavirus Disease 2019 (COVID-19) infection has been associated with endothelial injury and coronary microvascular dysfunction (CMD). We aimed to assess if there was an association between SARS-CoV-2 variants and the magnitude of CMD. Methods A prospective cohort of consecutive patients undergoing clinically indicated positron emission tomography (PET) myocardial perfusion imaging were included. Cases that had a polymerase chain reaction (PCR)-confirmed prior COVID-19 infection matched 1:3 on clinical and cardiovascular risk factors to controls with no prior COVID-19. Variants were estimated by the temporal prevalence at time of diagnosis based national reporting. Myocardial flow reserve (MFR) was determined by PET and CMD was defined as MFR<2. Results A total of 282 cases were matched to 869 controls;mean (+/-SD) age 65 (+/-12), 48% female. Most patients with prior COVID-19 infection were diagnosed when the Alpha/Beta variants were dominant (60.6% Alpha/Beta, 19.9% Omicron, 19.5% Delta). The highest rate of CMD was seen with patients diagnosed during the Delta dominance (56.4% Delta, 50% Omicron, 48.5% Alpha/Beta vs 27.7% controls, P for trend<0.001). Conclusion Our analysis shows the magnitude of COVID-19-associated CMD may differ based on the SARS-CoV-2 variant. [Formula presented]Copyright © 2023 American College of Cardiology Foundation

Extreme Angiographic-Physiologic Mismatch With Elevated Left Ventricular End-Diastolic Pressure.

Translesional coronary pressure measures the hemodynamic significance of epicardial coronary artery disease. Angiographic-physiologic mismatching is attributed mainly to imaging limitations. We present a patient with extreme visual-physiologic functional mismatch and a markedly elevated left ventricular end diastolic pressure (LVEDP) as a potential contributory mechanism.

CT fractional flow reserve: an alternative to stress ECHO for gatekeeping to invasive coronary angiography

Introduction: Stress echocardiography (SE) can assess the significance of moderate/severe stenoses found on CT coronary angiography (CTCA), as a gatekeeper to invasive coronary angiography (ICA). In 2017, the UK National Institute for Health and Care Excellence (NICE), recommended CT fractional flow reserve (CTFFR) on all patients with coronary stenoses on CTCA to reduce downstream ICA and reduce costs. Aim We describe our experience of using CTFFR and compare this with previously accepted practice of judicious use of SE in patients with moderate/ severe CTCA stenosis, and subsequent rate of ICA. Method: An electronic patient record identified patients undergoing CTFFR between January 2019 and March 2020, and CTCA between January 2017 and June 2018, at our centre. We assessed downstream testing following CT evidence of moderate/severe stenoses and undertook a cost analysis per patient (PP) with the following NHS tariffs;CTCA=£220, CTFFR=£530, SE=£177, ICA=£1000. Results: 140 patients were referred for CTFFR with 125 analysed (rejection rate 11%) of which 81 had moderate/severe stenoses. The baseline audit comprised 652 patients undergoing CTCA of which 92 had moderate/severe stenoses. Moderate CTCA stenosis: Baseline audit: 58 had moderate stenosis, 18 (31%) underwent SE, with 1 positive and subsequent ICA. 36 (62%) were referred directly for ICA. In total 17 (46%) were revascularised. Cost of £1224 PP. CTFFR audit: 44 had moderate stenosis, with 35 negative and 9 positive CTFFR. 9 (26%) and 7 (78%) following negative and positive CTFFR respectively, were subsequently referred for ICA. In total 16 (36%) were referred for ICA, and 44% revascularised. Cost of £1425 PP. Severe CTCA stenosis: Baseline audit: 34 had severe stenosis, 1 (3%) underwent SE. 33 (97%) were referred directly for ICA. In total 18 (60%) were revascularised. Cost of £1418 PP. CTFFR audit: 37 had severe stenoses, with 10 negative CTFFR and 27 positive CTFFR. 5 (50%) and 22 (81%) following negative and positive CTFFR respectively were referred for ICA. In total 27 (73%) were referred for ICA and 70% revascularised. Cost of £1719 PP. Importantly 14 patients underwent ICA following negative CTFFR with 29% revascularised. Conclusion: CTFFR use in all patients with moderate/severe stenosis reduced the rate of downstream ICA compared with previous judicious use of SE, albeit at greater cost and similar revascularisation rates. A small number of patients underwent ICA despite negative CTFFR due to clinical concerns. The NICE guidance recommending CTFFR on all patients with moderate/severe CTCA stenosis reduces ICA. However, assuming equal efficacy, based on the non-invasive arm of the Platform trial1, SE would achieve this at lower cost. Notably, CTFFR benefits from completing assessment within a single visit, which is pertinent in the COVID-19 era and negates inherent delays between multiple tests.

FIRST REPORTED CASE OF TAKOTSUBO CARDIOMYOPATHY INDUCED BY PERCUTANEOUS CORONARY INTERVENTION

Background: We report an unusual case of Takotsubo cardiomyopathy (TTC) caused by radial spasm during percutaneous coronary intervention (PCI), resulting in a fatal outcome. Case: A 70-year-old Caucasian female presented with an acute anterior myocardial infarction (MI) with anterior ST segment elevation. Coronary angiography showed critical proximal left anterior descending artery stenosis, and she underwent successful PCI via the right radial artery. Post-MI echocardiogram showed anterior wall hypokinesis with a left ventricular ejection fraction (LVEF) of 45%. The right coronary artery (RCA) had 70% stenosis in the mid-vessel and a staged outpatient intervention was planned. Decision-making: The staged procedure was delayed by seven months due to the COVID-19 pandemic. The same right radial access was selected but she developed significant radial spasm. Despite vasodilators, radial spasm persisted, so balloon-assisted tracking technique was used to advance guiding catheter. Fractional flow reserve of the RCA stenosis was positive at 0.76. PCI was then successfully performed using a 3x48 mm Xience stent. Thirty minutes later, she developed severe chest pain with widespread ST segment elevation. Repeat angiography via the right femoral artery showed patent coronary arteries. Echocardiography showed new apical ballooning pattern, typical of TTC with LVEF was 35%. She was discharged after 48 hours, but she re-presented a week later with cardiogenic shock. She had florid pulmonary oedema and an echo showed new torrential mitral regurgitation due anterior mitral leaflet chordal rupture. The apical ballooning that was observed a week earlier had resolved. An intra-aortic balloon pump was inserted, and the patient underwent emergency repair of the mitral valve. The procedure was technically successful, but the patient died on postoperative day one, due to multi-organ failure. Conclusion: We believe that TTC in our patient was caused by radial artery spasm. To our knowledge, this is the first case of TTC caused by radial spasm. Furthermore, chordal rupture secondary to TTC has been reported only once before.

A novel flow and pressure catheter for complete interventional cardiology physiology management

Ischemia with No Obstructive Coronary Artery (INOCA) in angina patients increases the risk of major cardiac events, with a 1.5x increased mortality rate. There is a link between COVID-19 infection and impairment in the myocardial micro-vasculation which may cause an increase of INOCA patients. Fractional Flow Reserve (FFR), is the standard of care in cardiology but its diagnostic function is only related to Obstructive Coronary Artery disease (or epicardial) and it is ineffective with INOCA. The lack of effective and accurate tools for timely evaluation of coronary impairments creates a clinical unmet need. The PhysioCath catheter was developed within the Eurostars project FPCatheter, E!113577 aims to resolve this need a provide an effective tool to interventional cardiologists. The main project outcome is a catheter prototype equipped with a blood flow velocity sensor based on a thermo-convection principle, and a fiber optic pressure sensor (based on Fabry-Perot principle). While the use of Fabry-Perot type of sensor is already standard in the industry, the use of a thermo-convection sensor represents a progress with respect the state of the art. The sensor creates an overheat of 7°C above the physiological blood's temperature (considered as being within the safety limits), and it exchanges thermal power with the blood stream. The power is then measured and converted to velocity by means of a calibration curve. The project encompassed interviews with 14 clinical experts, the summary of the interviews indicated that the preferred form of the device is an over the wire microcatheter, with rapid exchange. Within the project then, it was developed a 3Fr microcatheter, with a rapid exchange section of 24cm. Both pressure sensor and flow velocity sensor were integrated in this embodiment. Finally, the PhysioCath prototype was evaluated in a bench test study. The test setup was composed by an anatomical silicone phantom of the aortic root and the coronaries (Elastrat, Geneva, Switzerland), perfused with a peristaltic pump (Harvard Apparatus, Holliston MA, US). The measurements performed by the flow velocity sensor were compared against and external doppler flow velocity sensor. While the pressure measurement was assessed for stability and presence of drift. The data processing revealed and extreme accuracy in the measurement of flow based indexes like CFR (±6% variability), accuracy of the blood flow velocity measurement (±10%), and extreme stability in the measurement of both pressure and flow velocity. In the second part of the project (that is currently ongoing), it will be studied the performance of the device within an animal setting. In conclusion, the PhysioCath device is a microcatheter integrating bot pressure measurement and blood flow velocity measurement. Its performance is of very high accuracy and stability, that represent a main step ahead with respect the current state of the art, based mainly on thermodilution.

Relationship between adenosine A2a receptor polymorphism rs5751876 and fractional flow reserve during percutaneous coronary intervention.

Fractional flow reserve (FFR) assessed during adenosine-induced maximal hyperemia has emerged as a useful tool for the guidance of percutaneous coronary interventions (PCI). However, interindividual variability in the response to adenosine has been claimed as a major limitation to the use of adenosine for the measurement of FFR, carrying the risk of underestimating the severity of coronary stenoses, with potential negative prognostic consequences. Genetic variants of the adenosine receptor A2a (ADORA2A gene), located in the coronary circulation, have been involved in the modulation of the hyperemic response to adenosine. However, no study has so far evaluated the impact of the single nucleotide polymorphism rs5751876 of ADORA2A on the measurement of FFR in patients undergoing percutaneous coronary intervention that was, therefore, the aim of our study. We included patients undergoing coronary angiography and FFR assessment for intermediate (40-70%) coronary lesions. FFR measurement was performed by pressure-recording guidewire (Prime Wire, Volcano), after induction of hyperemia with intracoronary boli of adenosine (from 60 to 1440 µg, with dose doubling at each step). Restriction fragment length polymorphism (RFLP) analysis was performed to assess the presence of rs5751876 C>T polymorphism of ADORA2a receptor. We included 204 patients undergoing FFR measurement of 231 coronary lesions. A total of 134 patients carried the polymorphism (T allele), of whom 41 (30.6%) in homozygosis (T/T).Main clinical and angiographic features did not differ according to ADORA2A genotype. The rs5751876 C>T polymorphism did not affect mean FFR values (p = 0.91), the percentage of positive FFR (p = 0.54) and the duration of maximal hyperemia. However, the time to recovery to baseline FFR values was more prolonged among the T-allele carriers as compared to wild-type patients (p = 0.04). Based on these results, in patients with intermediate coronary stenoses undergoing FFR assessment with adenosine, the polymorphism rs5751876 of ADORA2A does not affect the peak hyperemic response to adenosine and the results of FFR. However, a more prolonged effect of adenosine was observed in T-carriers.