Psoas Muscle Area as a Predictor of Transcatheter Aortic Valve Implantation Outcomes.

BACKGROUND: Frailty is a well-recognised predictor of outcomes after transcatheter aortic valve implantation (TAVI). Psoas muscle area (PMA) is a surrogate marker for sarcopaenia and is a validated assessment tool for frailty. The objective of this study was to examine frailty as a predictor of outcomes in TAVI patients and assess the prognostic usefulness of adding PMA to established frailty assessments. METHODS: Frailty assessments were performed on 220 consecutive patients undergoing TAVI. These assessments used four markers (serum albumin, handgrip strength, gait speed, and a cognitive assessment), which were combined to form a composite frailty score. Preprocedural computed tomography scans were used to calculate cross-sectional PMA for each patient. The primary outcomes were all-cause mortality at 1-year and post-procedure length of hospital stay. RESULTS: Frailty status, as defined by the composite frailty score, was independently predictive of length of hospital stay (p=0.001), but not predictive of 1-year mortality (p=0.161). Albumin (p=0.036) and 5-metre walk test (p=0.003) were independently predictive of 1-year mortality. The PMA, when adjusted for gender, and normalised according to body surface area, was not predictive of 1-year mortality. Normalised PMA was associated with increased post-procedure length of stay within the female population (p=0.031). CONCLUSIONS: A low PMA is associated with increased length of hospital stay in female TAVI patients but does not provide additional predictive value over traditional frailty scores. The PMA was not shown to correlate with TAVI-related complications or 1-year mortality.

Aortic valve replacement reduces mortality in moderate aortic stenosis: a systematic review and meta-analysis.

BACKGROUND: With the introduction of transcatheter aortic valve replacement and an evolving understanding of the natural progression and history of aortic stenosis, the potential for earlier intervention in appropriate patients is promising; however, the benefit of aortic valve replacement in moderate aortic stenosis remains unclear. METHODS: Pubmed, Embase, and the Cochrane Library databases were searched up until 30th of December 2021 using keywords including moderate aortic stenosis and aortic valve replacement. Studies reporting all-cause mortality and outcomes in early aortic valve replacement (AVR) compared to conservative management in patients with moderate aortic stenosis were included. Hazard ratios were generated using random-effects meta-analysis to determine effect estimates. RESULTS: 3470 publications were screened with title and abstract review, which left 169 articles for full-text review. Of these studies, 7 met inclusion criteria and were included, totalling 4,827 patients. All studies treated AVR as a time-dependent co-variable in cox-regression multivariate analysis of all-cause mortality. Intervention with surgical or transcatheter AVR was associated with a 45% decreased risk of all-cause mortality (HR = 0.55 [0.42-0.68], I 2 = 51.5%, P < 0.001). All studies were representative of the overall cohort with appropriate sample sizes, with no evidence of publication, detection, or information biases in any of the studies. CONCLUSION: In this systematic review and meta-analysis, we report a 45% reduction in all-cause mortality in patients with moderate aortic stenosis who were treated with early aortic valve replacement compared to a strategy of conservative management. Randomised control trials are awaited to determine the utility of AVR in moderate aortic stenosis.

Trends in myocardial infarction and coronary revascularisation procedures in Australia, 1993-2017.

OBJECTIVE: Prior data have shown rising acute myocardial infarction (MI) trends in Australia; whether these increases have continued in recent years is not known. This study thus sought to characterise contemporary nationwide trends in MI hospitalisations and coronary procedures in Australia and their associated economic burden. METHODS: The primary outcome measure was the incidence and time trends of total MI, ST-elevation myocardial infarction (STEMI) and non-ST-elevation myocardial infarction (NSTEMI) hospitalisations from 1993 to 2017. The incidence and time trends of coronary procedures were additionally collected, alongside MI hospitalisation costs. RESULTS: Adjusted for population changes, annual MI incidence increased from 216.2 cases per 100 000 to a peak of 270.4 in 2007 with subsequent decline to 218.7 in 2017. Similarly, NSTEMI incidence increased from 68.0 cases per 100 000 in 1993 to a peak of 192.6 in 2007 with subsequent decline to 162.6 in 2017. STEMI incidence decreased from 148.3 cases per 100 000 in 1993 to 56.2 in 2017. Across the study period, there were annual increases in MI hospitalisations of 0.7% and NSTEMI hospitalisations of 5.6%, and an annual decrease in STEMI hospitalisations of 4.8%. Angiography and percutaneous coronary intervention increased by 3.4% and 3.3% annually, respectively, while coronary artery bypass graft surgery declined by 2.2% annually. MI hospitalisation costs increased by 100% over the study period, despite a decreased average length of stay by 45%. CONCLUSIONS: The rising incidence of MI hospitalisations appear to have stabilised in Australia. Despite this, associated healthcare expenditure remains significant, suggesting a need for continual implementation of public health policies and preventative strategies.

Surgical and percutaneous management of Aboriginal Australians with rheumatic heart disease: Timeliness and concordance between practice and guidelines.

BACKGROUND: Rheumatic heart disease (RHD) affects over 40 million people globally who are predominantly young and from impoverished communities. The barriers to valvular intervention are complex and contribute to the high morbidity and mortality associated with RHD. The rates of guideline indicated intervention in patients with significant RHD have not yet been reported. METHODS: From 2007 to 2017, we used the Australian Northern Territory Cardiac Database to identify patients with RHD who fulfilled at least one ESC/EACTS guideline indication for mitral valve intervention. Baseline clinical status, comorbidities, echocardiographic parameters, indication for intervention, referral and any interventions were recorded. RESULTS: 154 patients (mean age 38.5 ± 14.6, 66.1% female) were identified as having a class I or IIa indication for invasive management. Symptoms, atrial fibrillation and pulmonary hypertension were the most common indications for surgery (74.5%, 48.1%, 40.9%). From the onset of a guideline indication the actuarial rates of accepted referral and intervention within two-years were 66.0% ± 4.0% and 53.1% ± 4.4% respectively. Of those who were referred and accepted for intervention, 86% received it within 2 years. The rates of accepted referral for patients with class I indications were 72.5% ± 4.2% while class IIa indications were 42.5% ± 9.0% (p<0.001). CONCLUSIONS: Approximately half of Aboriginal patients with significant rheumatic mitral valve disease who met ESC/EACTS guideline indications for intervention received surgery or valvuloplasty within two-years. A significant difference in referral rates was found between Class I and Class IIa indications for valvular intervention.

Transcatheter aortic valve implantation: a new standard of care.

Aortic stenosis is the most common valvular lesion requiring intervention and with an ageing population, its burden is likely to increase. Increasing comorbidity and a desire for less invasive treatment strategies has facilitated the expansion of percutaneous aortic valve therapies. Robust clinical trial data are now available to support the role of transcatheter aortic valve implantation (TAVI) in patients of prohibitive, high and now intermediate surgical risk. The introduction of a Medicare Benefits Schedule reimbursement is likely to see TAVI use grow exponentially in Australia over the next 5 years. Clinical trials evaluating low risk patients may be the final frontier to see TAVI become the standard of care for most patients with severe aortic stenosis.

Transcatheter Aortic Valve Replacement: A Solution for the Young, Inoperable and Regurgitant.

Transcatheter aortic valve replacement (TAVR) has become an established treatment for patients with severe aortic stenosis and high surgical risk. Ten years of technological advances in valve structure and delivery systems alongside growing operator and centre experience has opened TAVR implantation to an increasingly broad range of patients. The extension to off-label use however needs careful consideration and monitoring. Through discussion of our case involving an inoperable 24-year-old male with severe aortic regurgitation (AR), we highlight the need for an experienced and multidisciplinary team, together with early and extensive patient and family disclosure and engagement, prior to considering any off-label application of TAVR.

MD: the new MB BS?

Having two types of medical degree in Australia runs the risk of creating a two-tiered system.

Atrial platelet reactivity in patients with atrial fibrillation.

BACKGROUND: Atrial fibrillation (AF) is associated with an increased risk of thrombus formation in the left but not the right atrium. The mechanisms underlying this differential effect on the atria are unknown. OBJECTIVE: The purpose of this study was to examine whether atrial-specific differences in platelet activation are present in patients with AF. METHODS: Nineteen patients (13 men and 6 women; age 60 +/- 2 years) with AF undergoing ablation in sinus rhythm were studied. Blood samples from the left atrium, right atrium, and femoral vein were obtained at the start of the procedure and analyzed by whole-blood flow cytometry for expression of platelet P-selectin (CD62P), vitronectin receptor (CD51/61), and active glycoprotein IIb/IIIa receptor (PAC-1). Platelet aggregation was evaluated using adenosine diphosphate (ADP)-induced whole-blood impedance aggregometry. Seven patients with left-sided accessory pathway also were studies as a reference group for the effect of transseptal puncture on platelet reactivity. RESULTS: Platelet P-selectin levels were significantly elevated in the left atrium compared to the right atrium (10.2% +/- 2.5% vs 8.6% +/- 2.3%, P <.05). CD51/61 and PAC-1 levels did not differ between sampling sites. ADP-induced platelet aggregation was significantly higher in the left atrium compared to the right atrium and femoral vein (P <.05 for both). Platelet P-selectin levels and ADP-induced platelet aggregation did not differ between sampling site in the reference group. CONCLUSION: In patients with AF, left atrial platelet reactivity is increased compared to the right atria and peripheral circulation. The study data suggest that the presence of chamber-specific platelet activation may explain, in part, the propensity for left atrial thrombus formation in patients with AF.

High-density mapping of atrial fibrillation in humans: relationship between high-frequency activation and electrogram fractionation.

INTRODUCTION: Sites of complex fractionated atrial electrograms (CFAE) and dominant frequency (DF) have been implicated in maintaining atrial fibrillation (AF); however, their relationship is poorly understood. METHODS AND RESULTS: Twenty patients underwent biatrial high-density contact mapping (507 +/- 150 points/patient) during AF. CFAE were characterized using software to quantify electrogram complexity (CFE-mean). Spectral analysis determined the frequency with greatest power and sites of high DF with a frequency gradient. CFE-mean was higher (less fractionated) for right compared with left atria (P < 0.001) and in paroxysmal compared with persistent AF (P < 0.001). DF was lower for right compared with left atria (P = 0.02) and in paroxysmal compared with persistent AF (P < 0.001). There was significant regional variation in DF in paroxysmal (P < 0.001) but not persistent AF. Highest DF points clustered together with 5.2 +/- 1.7 clusters/patient. Correlation between CFE-mean and DF was poor on a point-by-point basis (r =-0.17, P < 0.001), but moderate on an individual basis (r =-0.50, P = 0.03). Exploration of their spatial relationship demonstrated CFAE areas in close proximity (median 5 mm, IQR 2-10) to high DF sites; within 10 mm in 80% and 10-20 mm in 10%. Simultaneous activation mapping at these sites further supports this observation. CONCLUSION: Greater fractionation and higher DF are seen in persistent AF and left atria during AF. Preferential areas of high DF are observed in paroxysmal but not persistent AF. CFAE and DF correlate within an individual but not point-by-point. Exploration of their spatial relationship demonstrates CFAE in areas adjacent to high DF, and this is supported by activation mapping at these sites.

Image integration using NavX Fusion: initial experience and validation.

BACKGROUND: Three-dimensional virtual anatomic navigation is increasingly used during mapping and ablation of complex arrhythmias. NavX Fusion software aims to mold the virtual anatomy to the patient's computed tomography (CT) image; however, the accuracy and clinical usefulness of this system have not been reported. OBJECTIVE: The purpose of this study was to assess the accuracy and describe the initial experience of CT image integration using NavX Fusion for atrial fibrillation ablation. METHODS: This study consisted of 55 consecutive patients undergoing atrial fibrillation ablation using NavX Fusion navigation. Left atrial NavX geometries were compared to a corresponding CT for geometric match. Geometric match, expressed as the difference in millimeters between CT and NavX geometry, was calculated for the original geometry (GEO-1), field scaled and primary fused geometry (GEO-2), and final secondary fused geometry (GEO-3). Navigational accuracy was assessed by moving the catheter to 10 discrete anatomic sites and determining the distance between the catheter tip and the closest GEO-2, GEO-3, and CT surface. Fusion integration time and procedural and fluoroscopic durations were recorded to assess clinical usefulness. RESULTS: GEO-1, GEO-2 and GEO-3 were associated with CT-GEO errors of 6.6+/-2.8 mm, 4.1+/-0.7 mm, 1.9+/-0.4 mm, respectively. Navigational accuracy was not significantly different for GEO-2, GEO-3, and CT at 3.4+/-1.6 mm to any surface. A significant (P < or =.001) inverse curvilinear relationship was present between case number and the time required for image integration (r(2) = 0.35) and the fluoroscopic time normalized for procedural duration (r(2) = 0.18). CONCLUSION: Image integration using the NavX Fusion software is highly accurate and is associated with a progressive reduction in fluoroscopic time relative to procedural duration.

The effect of electrogram duration on quantification of complex fractionated atrial electrograms and dominant frequency.

INTRODUCTION: Sites of complex fractionated atrial electrograms (CFAEs) and highest dominant frequency (DF) have been proposed as critical regions maintaining atrial fibrillation (AF). This study aimed to determine the minimum electrogram recording duration that accurately characterizes CFAE or DF sites for ablation without unduly lengthening the procedure. METHODS AND RESULTS: Fourteen patients with AF undergoing catheter ablation had high-density (498 +/- 174 points) biatrial mapping performed during AF before ablation. At each point, 8-second electrograms were recorded. CFAE characterization using the NavX software provided a representation of electrogram complexity (CFE-mean). CFE-mean for each point from 7-, 6-, 5-, 4-, 3-, 2-, and 1-second subsamples were compared with the index 8-second CFE-mean. Offline spectral analysis defined DF as the frequency with greatest power, and DF of subsamples were compared with index DF. Index 8-second electrogram CFE-mean was 114 +/- 20 ms for right atria and 102 +/- 17 ms for left atria (P = 0.01); DF was 5.7 +/- 0.8 Hz for right atria and 6.0 +/- 0.8 Hz for left atria (P = 0.02). Means from shorter electrograms were nonsignificantly decreased for CFE-mean and overestimated for DF (P < 0.001). Mean absolute differences between subsampled and index values ranged from 3.3 to 20.1 ms for CFE-mean and 0.11 to 1.18 Hz for DF. Subsampled electrograms deviating >10% from index values ranged from 2.5 to 56% for CFE-mean and 3.5 to 41% for DF. Intraclass correlation coefficients ranged from 0.992 to 0.788 for CFE-mean and 0.897 to 0.233 for DF. Unacceptable differences from index values were found with CFE-mean and DF from electrograms <5 seconds. CONCLUSION: Electrograms of >or=5-second duration are required to accurately characterize CFAE and DF sites for ablation.