Utilising pyrophosphate uptake imaging to establish the timing of acute myocardial infarction: An often-forgotten art.

INTRODUCTION: While pyrophosphate uptake imaging with Technetium-99 m pyrophosphate (Tc-99 m PYP) is frequently used for cardiac ATTR amyloid imaging, its role in determining the timing of acute myocardial infarction (AMI) is near forgotten. We present a case that demonstrates the clinical benefit of pyrophosphate uptake imaging in differentiating recent from remote infarction as a reminder of the continued utility of pyrophosphate uptake imaging for this indication. CASE AND OUTCOMES: A 68-year-old male was referred for surgical replacement of his bicuspid aortic valve with severe aortic regurgitation. He was clinically well, but an elective pre-operative electrocardiogram suggested an anteroseptal wall infarct of possibly recent onset. Troponin-I was elevated at 430 ng/L (N < 26 ng/L) but did not change significantly over several days. Coronary angiography confirmed an occluded left anterior descending artery. Tc-99 m PYP uptake imaging was then utilised to determine the age of infarct and demonstrated mild regional tracer uptake in the left ventricular apex, consistent with a recent infarction. As the infarct was recent, elective surgery was postponed. DISCUSSION: In this case, the age of the patient's AMI had an important bearing on the timing of his elective surgical aortic valve replacement. Given the recommendation to delay elective cardiac surgery in patients with recent myocardial infarction to reduce peri­operative morbidity and mortality, this now rare use of pyrophosphate uptake imaging was critical in helping determine when cardiac surgery could be performed safely. CONCLUSION: This case demonstrates the clinical utility of pyrophosphate uptake imaging in establishing the temporal profile of myocardial infarction to help guide appropriate clinical management.

Impact of Telehealth on Failure to Attend Rates and Patient Re-Engagement in Adult Congenital Heart Disease Clinic.

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic paved the way for telehealth consultations. We aimed to determine the impact of telehealth on rates of failure to attend (FTA) in adult congenital heart disease (ACHD) clinics and whether telehealth could re-engage patients with previous FTA face-to-face appointments. METHODS: This was a retrospective audit of a tertiary ACHD clinic over a 12-month pre-telehealth (26 March 2019-17 March 2020) and 12-month post-telehealth implementation period (24 March 2020-16 March 2021). Patients with one or more FTAs during the 24-month study period were included. Our ACHD clinic is run three times per month. Patients with ACHD are offered lifelong follow-up and reviewed annually on average. Re-engagement was defined as two or more consecutive face-to-face FTAs immediately before the telehealth period with subsequent attendance of their telehealth appointment. RESULTS: A total of 359 patients with a total of 623 FTAs were included. Complexity of congenital heart disease was moderate in 56% (202/359) and severe in 19% (69/359) of patients. Overall FTA rate was 18% (623/3,452). FTA rate was significantly lower in the post-telehealth period (15%, 257/1,664) compared with the pre-telehealth period (20%, 366/1,788) (p<0.00001). At study conclusion, 1% of patients had died (5/359). Of the 354 remaining patients, 42% (150/354) were considered lost to follow-up (two or more FTAs including telehealth), 37% (132/354) missed only one clinic appointment, and 20% (72/354) previously considered lost to follow-up had re-engaged in the telehealth period. CONCLUSIONS: Rates of FTA in a tertiary ACHD clinic significantly reduced after the introduction of telehealth consultation. A fifth of patients considered lost to follow-up were re-engaged with telehealth. Additional strategies to further reduce FTA should be explored.

Assessment of Coronary Artery Obstruction Risk During Transcatheter Aortic Valve Replacement Utilising 3D-Printing.

BACKGROUND: Current imaging techniques may inadequately rule out coronary artery obstruction (CAO), a potentially fatal complication during transcatheter aortic valve replacement (TAVR). Advancements in three-dimensional (3D)-printing allow the development of models capable of replicating cardiac anatomy and predicting CAO. We sought to simulate TAVR utilising 3D-printed cardiac models to improve CAO risk assessment and procedural safety. METHODS: Thirteen (13) patients with aortic stenosis at high-risk of CAO during TAVR were selected for 3D-printed modelling. The relevant anatomy for TAVR was precisely reconstructed with Materialise Heart Print-Flex (Materialse, Leuven, Belgium) technology. An appropriately sized valve prosthesis was deployed in each 3D-model and coronary ostia assessed for obstruction. RESULTS: Model-derived results were compared to clinical outcomes in 13 cases. One high-risk case underwent TAVR resulting in left main obstruction and subsequent stenting. This outcome was accurately predicted by the 3D-model simulation. Two (2) high-risk TAVR cases were abandoned following transient CAO during balloon aortic valvuloplasty (BAV). The 3D-model simulations correlated with these findings, demonstrating CAO either by a calcium nodule or the native valve leaflet. In another two cases, BAV was uncertain, however the 3D-simulation demonstrated patency and successful TAVR was undertaken. In remaining cases, no obstruction was demonstrated in-vitro, and all underwent uncomplicated TAVR. CONCLUSIONS: In this proof-of-concept study, 3D-model TAVR simulation correlates well to clinical outcomes. 3D-models of patients at high-risk of CAO may be utilised in pre-procedural planning to accurately predict this complication. As lower-risk surgical cohorts are considered for TAVR, 3D-models may minimise complications leading to safer patient outcomes.