Cardiac computed tomography post-transcatheter aortic valve replacement.

Transcatheter aortic valve replacement (TAVR) is performed to treat aortic stenosis and is increasingly being utilised in the low-to-intermediate-risk population. Currently, attention has shifted towards long-term outcomes, complications and lifelong maintenance of the bioprosthesis. Some patients with TAVR in-situ may develop significant coronary artery disease over time requiring invasive coronary angiography, which may be problematic with the TAVR bioprosthesis in close proximity to the coronary ostia. In addition, younger patients may require a second transcatheter heart valve (THV) to 'replace' their in-situ THV because of gradual structural valve degeneration. Implantation of a second THV carries a risk of coronary obstruction, thereby requiring comprehensive pre-procedural planning. Unlike in the pre-TAVR period, cardiac CT angiography in the post-TAVR period is not well established. However, post-TAVR cardiac CT is being increasingly utilised to evaluate mechanisms for structural valve degeneration and complications, including leaflet thrombosis. Post-TAVR CT is also expected to have a significant role in risk-stratifying and planning future invasive procedures including coronary angiography and valve-in-valve interventions. Overall, there is emerging evidence for post-TAVR CT to be eventually incorporated into long-term TAVR monitoring and lifelong planning.

Artificial Intelligence-Enabled Quantitative Coronary Plaque and Hemodynamic Analysis for Predicting Acute Coronary Syndrome.

BACKGROUND: A lesion-level risk prediction for acute coronary syndrome (ACS) needs better characterization. OBJECTIVES: This study sought to investigate the additive value of artificial intelligence-enabled quantitative coronary plaque and hemodynamic analysis (AI-QCPHA). METHODS: Among ACS patients who underwent coronary computed tomography angiography (CTA) from 1 month to 3 years before the ACS event, culprit and nonculprit lesions on coronary CTA were adjudicated based on invasive coronary angiography. The primary endpoint was the predictability of the risk models for ACS culprit lesions. The reference model included the Coronary Artery Disease Reporting and Data System, a standardized classification for stenosis severity, and high-risk plaque, defined as lesions with ≥2 adverse plaque characteristics. The new prediction model was the reference model plus AI-QCPHA features, selected by hierarchical clustering and information gain in the derivation cohort. The model performance was assessed in the validation cohort. RESULTS: Among 351 patients (age: 65.9 ± 11.7 years) with 2,088 nonculprit and 363 culprit lesions, the median interval from coronary CTA to ACS event was 375 days (Q1-Q3: 95-645 days), and 223 patients (63.5%) presented with myocardial infarction. In the derivation cohort (n = 243), the best AI-QCPHA features were fractional flow reserve across the lesion, plaque burden, total plaque volume, low-attenuation plaque volume, and averaged percent total myocardial blood flow. The addition of AI-QCPHA features showed higher predictability than the reference model in the validation cohort (n = 108) (AUC: 0.84 vs 0.78; P < 0.001). The additive value of AI-QCPHA features was consistent across different timepoints from coronary CTA. CONCLUSIONS: AI-enabled plaque and hemodynamic quantification enhanced the predictability for ACS culprit lesions over the conventional coronary CTA analysis. (Exploring the Mechanism of Plaque Rupture in Acute Coronary Syndrome Using Coronary Computed Tomography Angiography and Computational Fluid Dynamics II [EMERALD-II]; NCT03591328).

Early SGLT2 inhibitor use is associated with improved left atrial strain following acute coronary syndrome.

AIM: Left atrial (LA) strain, a novel marker of LA function, reliably predicts diastolic dysfunction. SGLT2 inhibitors improve heart failure outcomes, but limited data exists regarding their use in the immediate aftermath of acute coronary syndrome (ACS). We studied the effect of empagliflozin on LA strain in patients with type 2 diabetes (T2D) and ACS. METHODS: Patients with ACS and T2D were identified and empagliflozin was initiated in eligible patients prior to discharge. Patients not initiated on empagliflozin were analysed as a comparator group. A blinded investigator assessed LA strain using baseline and 3-6 month follow-up echocardiograms. RESULTS: Forty-four participants (n = 22 each group) were included. Baseline characteristics and LA strain were similar in the two groups. LA reservoir, conduit and contractile strain increased in empagliflozin group (28.0 ± 8.4% to 34.6 ± 12.2% p < 0.001, 14.5 ± 5.4% to 16.7 ± 7.0% p = 0.034, 13.5 ± 5.2% to 17.9 ± 7.2% p = 0.005, respectively) but remained unchanged in comparison group (29.2 ± 6.7% to 28.8 ± 7.0%, 12.8 ± 4.2% to 13.3 ± 4.7%, 16.7 ± 5.3% to 15.5 ± 4.5%, respectively, p = NS). The difference in change between groups was significant for LA reservoir (p = 0.003) and contractile strain (p = 0.005). CONCLUSION: In patients with ACS and T2D, addition of empagliflozin to standard ACS therapy prior to discharge is associated with improved LA function.

Telehealth during COVID-19 restrictions in patients with cardiovascular disease: impact on medication prescriptions and patient satisfaction.

BACKGROUND AND AIMS: Telehealth plays an integral part in healthcare delivery. The impact of telehealth and the COVID-19 pandemic on medication prescribing and patient satisfaction with telehealth in cardiology clinics remains unknown. METHODS: A retrospective study of cardiology clinic patients at an Australian tertiary hospital was conducted; 630 patients seen before the COVID-19 pandemic (0.6% telehealth) and 678 during the pandemic (91.2% telehealth) were included. Medication changes, new prescriptions and time to obtaining prescriptions after clinic were compared. To evaluate patients' experiences, cardiology clinic patients reviewed during the pandemic were prospectively invited to participate in an electronic survey sent to their mobile phones. RESULTS: The overall rates of medication changes made in the clinic between the prepandemic and the pandemic periods did not differ significantly (26.9% vs 25.8%). Compared with prepandemic, new cardiac medication prescriptions during clinic were significantly less (9.3% vs 2.5%; P < 0.0001) and recommendations to general practitioners (GP) to initiate cardiac medications were significantly more (2.6% vs 9.1%; P < 0.0001). Time to obtaining new prescriptions was significantly longer in the pandemic cohort (median 0 days (range: 0-32) vs 10.5 days (range: 0-231); P < 0.0001). Two hundred forty-three (32.7%) patients participated in the survey; 50% reported that telehealth was at least as good as face-to-face consultations. Most patients (61.5%) were satisfied with telehealth and most (62.9%) wished to see telehealth continued postpandemic. CONCLUSION: Telehealth during the COVID-19 pandemic was associated with greater reliance on GP to prescribe cardiac medications and delays in obtaining prescriptions among cardiology clinic patients. Although most patients were satisfied with telehealth services, nearly half of the cardiac patients expressed preference towards traditional face-to-face consultations.

3D printing of heart valves.

3D printing technologies have the potential to revolutionize the manufacture of heart valves through the ability to create bespoke, complex constructs. In light of recent technological advances, we review the progress made towards 3D printing of heart valves, focusing on studies that have utilised these technologies beyond manufacturing patient-specific moulds. We first overview the key requirements of a heart valve to assess functionality. We then present the 3D printing technologies used to engineer heart valves. By referencing International Organisation for Standardisation (ISO) Standard 5840 (Cardiovascular implants - Cardiac valve prostheses), we provide insight into the achieved functionality of these valves. Overall, 3D printing promises to have a significant positive impact on the creation of artificial heart valves and potentially unlock full complex functionality.

Evaluation of stable chest pain following emergency department presentation: Impact of first-line cardiac computed tomography diagnostic strategy in an Australian setting.

OBJECTIVE: International guidelines provide increasing support for computed tomography coronary angiography (CTCA) in investigating chest pain. A pathway utilising CTCA first-line for outpatient stable chest pain evaluation was implemented in an Australian ED. METHODS: In pre-post design, the impact of the pathway was prospectively assessed over 6 months (August 2021 to January 2022) and compared with a 6-month pre-implementation group (February 2021 to July 2021). CTCA was recommended first-line in suspected stable cardiac chest pain, followed by chest pain clinic review. Predefined criteria were provided recommending functional testing in select patients. The impact of CTCA versus functional testing was evaluated. Data were obtained from digital medical records. RESULTS: Three hundred and fifteen patients were included, 143 pre-implementation and 172 post-implementation. Characteristics were similar except age (pre-implementation: 58.9 ± 12.0 vs post-implementation: 62.8 ± 12.3 years, P = 0.004). Pathway-guided management resulted in higher first-line CTCA (73.3% vs 46.2%, P < 0.001), lower functional testing (30.2% vs 56.6%, P < 0.001) and lower proportion undergoing two non-invasive tests (4.7% vs 10.5%, P = 0.047), without increasing investigation costs or invasive coronary angiography (ICA) (pre-implementation: 13.3% vs post-implementation: 9.3%, P = 0.263). In patients undergoing CTCA, 40.7% had normal coronaries and 36.2% minimal/mild disease, with no difference in disease burden post-implementation. More medication changes occurred following CTCA compared with functional testing (aspirin: P = 0.005, statin: P < 0.001). In patients undergoing ICA, revascularisation to ICA ratio was higher following CTCA compared with functional testing (91.7% vs 18.2%, P < 0.001). No 30-day myocardial infarction or death occurred. CONCLUSIONS: The pathway increased CTCA utilisation and reduced downstream investigations. CTCA was associated with medication changes and improved ICA efficiency.

A streamlined Emergency Department approach to moderate risk chest pain in patients with no pre-existing coronary artery disease: A pilot study.

OBJECTIVE: Moderate risk patients with chest pain and no previously diagnosed coronary artery disease (CAD) who present to ED require further risk stratification. We hypothesise that management of these patients by ED physicians can decrease length of stay (LOS), without increasing patient harm. METHODS: A prospective pilot study with comparison to a pre-intervention control group was performed on patients presenting with chest pain to an ED in Perth, Australia between May and October 2021, following the introduction of a streamlined guideline consisting of ED led decision making and early follow up. Patients had no documented CAD and were at moderate risk of major adverse cardiac events (MACE). Electronic data was used for comparison. Primary outcomes were total LOS and LOS following troponin. RESULTS: One hundred eighty-six patients were included. Median total LOS was reduced by 62 min, but this change was not statistically significant (482 [360-795] vs 420 [360-525] min, P = 0.06). However, a significant 60 min decrease in LOS was found following the final troponin (240 (120-571) vs 180 (135-270) min, P = 0.02). There was no difference in the rate of MACE (0% vs 2%, P = 0.50), with no myocardial infarction or death. CONCLUSIONS: Our study suggests that patients with no pre-existing CAD can be safely managed by emergency physicians streamlining their ED management and decreasing LOS. This pathway could be used in other centres following confirmation of the results by a larger study.

Enhancing Risk Stratification on Coronary Computed Tomography Angiography: The Role of Artificial Intelligence.

PURPOSE: To describe and outline the role of artificial intelligence (AI) in assisting coronary computed tomography angiography (CCTA) in enhancing risk stratification. METHODS: A comprehensive review of the literature was performed to identify published work investigating the utility of applying AI to CCTA. FINDINGS: CCTA is an excellent diagnostic tool for the detection of atherosclerotic cardiovascular disease. The noninvasive nature and high diagnostic accuracy have made CCTA a viable alternative to invasive coronary angiography to detect luminal stenosis. However, it is now understood that stenosis is just one factor that predicts cardiac risk and other factors need to be considered. CCTA-derived plaque biomarkers have since emerged as established predictors of cardiac events to improve risk stratification. Despite awareness of these biomarkers, they are still yet to be incorporated into routine clinical practice. The major barriers to implementation include the specialized skills required for image evaluation and the time intensive nature of analysis. With the many recent advancements in the technology, AI presents itself as a promising solution. AI is attractive because it has the potential to rapidly automate technically challenging tasks with exceptional accuracy. IMPLICATIONS: Developments in the field of AI are occurring at a rapid rate. There is already increasing evidence of the potential AI has to greatly improve the utility of CCTA by improving analysis time and extracting additional prognostic data from new plaque biomarkers. There are, however, technical and ethical challenges that need to be considered before implementing such technology into routine clinical practice.

Impact of Post-PCI FFR Stratified by Coronary Artery.

BACKGROUND: Low fractional flow reserve (FFR) after percutaneous coronary intervention (PCI) has been associated with adverse clinical outcomes. Hitherto, this assessment has been independent of the epicardial vessel interrogated. OBJECTIVES: This study sought to assess the predictive capacity of post-PCI FFR for target vessel failure (TVF) stratified by coronary artery. METHODS: We performed a systematic review and individual patient-level data meta-analysis of randomized clinical trials and observational studies with protocol-recommended post-PCI FFR assessment. The difference in post-PCI FFR between left anterior descending (LAD) and non-LAD arteries was assessed using a random-effect models meta-analysis of mean differences. TVF was defined as a composite of cardiac death, target vessel myocardial infarction, and clinically driven target vessel revascularization. RESULTS: Overall, 3,336 vessels (n = 2,760 patients) with post-PCI FFR measurements were included in 9 studies. The weighted mean post-PCI FFR was 0.89 (95% CI: 0.87-0.90) and differed significantly between coronary vessels (LAD = 0.86; 95% CI: 0.85 to 0.88 vs non-LAD = 0.93; 95% CI: 0.91-0.94; P < 0.001). Post-PCI FFR was an independent predictor of TVF, with its risk increasing by 52% for every reduction of 0.10 FFR units, and this was mainly driven by TVR. The predictive capacity for TVF was poor for LAD arteries (AUC: 0.52; 95% CI: 0.47-0.58) and moderate for non-LAD arteries (AUC: 0.66; 95% CI: 0.59-0.73; LAD vs non-LAD arteries, P = 0.005). CONCLUSIONS: The LAD is associated with a lower post-PCI FFR than non-LAD arteries, emphasizing the importance of interpreting post-PCI FFR on a vessel-specific basis. Although a higher post-PCI FFR was associated with improved prognosis, its predictive capacity for events differs between the LAD and non-LAD arteries, being poor in the LAD and moderate in the non-LAD vessels.

Clinical outcomes and health care costs of transferring rural Western Australians for invasive coronary angiography, and a cost-effective alternative care model: a retrospective cross-sectional study.

OBJECTIVES: To examine the severity of coronary artery disease (CAD) in people from rural or remote Western Australia referred for invasive coronary angiography (ICA) in Perth and their subsequent management; to estimate the cost savings were computed tomography coronary angiography (CTCA) offered in rural centres as a first line investigation for people with suspected CAD. DESIGN: Retrospective cohort study. SETTING, PARTICIPANTS: Adults with stable symptoms in rural and remote WA referred to Perth public tertiary hospitals for ICA evaluation during the 2019 calendar year. MAIN OUTCOME MEASURES: Severity and management of CAD (medical management or revascularisation); health care costs by care model (standard care or a proposed alternative model with local CTCA assessment). RESULTS: The mean age of the 1017 people from rural and remote WA who underwent ICA in Perth was 62 years (standard deviation, 13 years); 680 were men (66.9%), 245 were Indigenous people (24.1%). Indications for referral were non-ST elevation myocardial infarction (438, 43.1%), chest pain with normal troponin level (394, 38.7%), and other (185, 18.2%). After ICA assessment, 619 people were medically managed (60.9%) and 398 underwent revascularisation (39.1%). None of the 365 patients (35.9%) without obstructed coronaries (< 50% stenosis) underwent revascularisation; nine patients with moderate CAD (50-69% stenosis; 7%) and 389 with severe CAD (≥ 70% stenosis or occluded vessel; 75.5%) underwent revascularisation. Were CTCA used locally to determine the need for referral, 527 referrals could have been averted (53%), the ICA:revascularisation ratio would have improved from 2.6 to 1.6, and 1757 metropolitan hospital bed-days (43% reduction) and $7.3 million in health care costs (36% reduction) would have been saved. CONCLUSION: Many rural and remote Western Australians transferred for ICA in Perth have non-obstructive CAD and are medically managed. Providing CTCA as a first line investigation in rural centres could avert half of these transfers and be a cost-effective strategy for risk stratification of people with suspected CAD.

Characteristics and Outcomes of Young Patients With ST-Elevation Myocardial Infarction Without Standard Modifiable Risk Factors.

Patients with ST-elevation myocardial infarction (STEMI) with no standard modifiable risk factors (SMuRFs: hypertension, diabetes mellitus, hypercholesterolemia, and smoking) have worse short-term mortality than those with SMuRFs. Whether this association extends to younger patients is unclear. A retrospective cohort study was performed of patients aged 18 to 45 years with STEMI at 3 Australian hospitals between 2010 and 2020. Nonatherosclerotic causes of STEMI were excluded. The primary outcome was 30-day all-cause mortality. Secondary outcomes included 1 and 2-year mortality. Cox proportional hazards analysis was used. Of 597 patients, the median age was 42 (interquartile range 38 to 44) years, 85.1% were men and 8.4% were SMuRF-less. Patients who are SMuRF-less were >2 times more likely to have cardiac arrest (28.0% vs 12.6%, p = 0.003); require vasopressors (16.0% vs 6.8%, p = 0.018), mechanical support (10.0% vs 2.3%, p = 0.046), or intensive care admission (20.0% vs 5.7%, p <0.001); and have higher rate of left anterior descending artery infarcts than those with SMuRFs (62.0% vs 47.2%, p = 0.045). No significant differences in thrombolysis or percutaneous intervention were observed. Guideline-directed medical therapy at discharge was high (>90%), and not different in the SMuRF-less. 30-day mortality was almost fivefold higher in the SMuRF-less (hazard ratio 4.70, 95% confidence interval 1.66 to 13.35, p = 0.004), remaining significant at 1 and 2 years. In conclusion, young patients who are SMuRF-less have a higher 30-day mortality after STEMI than their counterparts with SMuRFs. This may be partially mediated by higher rates of cardiac arrest and left anterior descending artery territory events. These findings further highlight the need for improved prevention and management of SMuRF-less STEMI.

Artificial Intelligence in Cardiology: An Australian Perspective.

Significant advances have been made in artificial intelligence technology in recent years. Many health care applications have been investigated to assist clinicians and the technology is close to being integrated into routine clinical practice. The high prevalence of cardiac disease in Australia places overwhelming demands on the existing health care system, challenging its capacity to provide quality patient care. Artificial intelligence has emerged as a promising solution. This discussion paper provides an Australian perspective on the current state of artificial intelligence in cardiology, including the benefits and challenges of implementation. This paper highlights some current artificial intelligence applications in cardiology, while also detailing challenges such as data privacy, ethical considerations, and integration within existing health infrastructures. Overall, this paper aims to provide insights into the potential benefits of artificial intelligence in cardiology, while also acknowledging the barriers that need to be addressed to ensure safe and effective implementation into an Australian health system.