Leaflet immobility and thrombosis in transcatheter aortic valve replacement.

Transcatheter aortic valve replacement (TAVR) has grown exponentially worldwide in the last decade. Due to the higher bleeding risks associated with oral anticoagulation and in patients undergoing TAVR, antiplatelet therapy is currently considered first-line antithrombotic treatment after TAVR. Recent studies suggest that some patients can develop subclinical transcatheter heart valve (THV) thrombosis after the procedure, whereby thrombus forms on the leaflets that can be a precursor to leaflet dysfunction. Compared with echocardiography, multidetector computed tomography is more sensitive at detecting THV thrombosis. Transcatheter heart valve thrombosis can occur while on dual antiplatelet therapy with aspirin and thienopyridine but significantly less with anticoagulation. This review summarizes the incidence and diagnostic criteria for THV thrombosis and discusses the pathophysiological mechanisms that may lead to thrombus formation, its natural history, potential clinical implications and treatment for these patients.

The Prevalence of Pacing-Induced Cardiomyopathy (PICM) in Patients With Long Term Right Ventricular Pacing - Is it a Matter Of Definition?

BACKGROUND: Chronic right ventricular pacing may contribute to deterioration in left ventricular ejection fraction (LVEF). The aim of the study was to identify the prevalence of pacing-induced cardiomyopathy (PICM) in patients with chronic right ventricular pacing. METHODS: Patients attending a pacemaker clinic were retrospectively identified as having had transthoracic echocardiographic LVEF measurement during the 12 months prior to device implantation. Those with cardioverter-defibrillators or biventricular devices were excluded. The remaining patients were invited back for a repeat echocardiogram. Three (3) different definitions of PICM were employed: 1) follow-up LVEF of ≤40% if baseline LVEF was ≥50%, or an absolute reduction in LVEF ≥5% if baseline LVEF was <50%; 2) follow-up LVEF of ≤40% if baseline LVEF was ≥50%, or an absolute reduction in LVEF ≥10% if baseline LVEF was ≤50%; 3) absolute reduction in LVEF ≥10% irrespective of baseline LVEF. Alternate causes of cardiomyopathy were excluded following a chart review. RESULTS: The study cohort of 118 included 67 males (mean age 77.8±10.5years) and 51 females (mean age 76.8±11.2years). The mean time between baseline and follow-up echocardiograms was 3.5+1.4years (range 1.5-6.4 years). The prevalence of PICM ranged from 5.9 to 39.0% depending on PICM definition. Multivariate analysis found that PICM was significantly associated with ventricular pacing burden (p=0.013). CONCLUSIONS: The prevalence of pacing induced cardiomyopathy is dependent on current accepted clinical definitions. A clear definition of PICM is required for a better understanding of the clinical implications of right ventricular pacing.

Application of left ventricular strain in patients with aortic and mitral valve disease.

PURPOSE OF REVIEW: Left ventricular (LV) global longitudinal strain (GLS) is widely recognized as a more sensitive measure of LV systolic function compared with LV ejection fraction (LVEF). In addition, the measurement of LVGLS is more reproducible than two-dimensional LVEF. Current guidelines for diagnosis and treatment of valvular heart disease include LVEF as one of the parameters to take into consideration in the clinical decision-making. However, a large body of evidence is showing that LVGLS may be a better prognosticator than LVEF in various valvular heart diseases. In this timely state-of-the-art review, the evidence and role of LVGLS as a clinical tool in patients with aortic and mitral valve disease is appraised. RECENT FINDINGS: Majority of research on LVGLS and valvular heart disease focused on high-gradient aortic stenosis. Increasingly, LVGLS has also been shown to be prognostic in low-flow, low-gradient severe aortic stenosis with preserved LVEF, and in low-flow, low-gradient severe aortic stenosis with reduced LVEF. The role of LV GLS in patients with aortic regurgitation and mitral regurgitation is less well established. SUMMARY: LVGLS is increasingly used to identify subclinical myocardial dysfunction in patients with valvular heart disease to identify optimal timing for surgery and prognosticate outcomes after surgery.

An Unusual Cause of Out-of-Hospital Cardiac Arrest Recorded on a Heartrate Monitor.

Coronary vasospasm is an uncommon, but perhaps under-recognised, cause of cardiac arrest. We present a novel case of an exercise-induced out-of-hospital cardiac arrest due to coronary vasospasm, captured on a heartrate monitor, and discuss the management options for this condition.

Exploring Noninvasive Tricuspid dP/dt as a Marker of Right Ventricular Function.

BACKGROUND: Right ventricular (RV) function assumes prognostic significance in various disease states, but RV geometry is not amenable to volumetric assessment by two-dimensional echocardiography. Intra-ventricular pressure rate of rise (dP/dt) predicts myocardial contractility and adjusting for the maximal regurgitant velocity (Vmax) corrects for preload. We examined the relationship of noninvasive tricuspid dP/dt and dP/dt/Vmax with RV ejection fraction (RVEF) by cardiac magnetic resonance imaging (CMR) as a measure of RV function. METHODS: Fifty CMRs and echocardiograms performed within 30 days were included. Tricuspid regurgitation (TR) spectral Doppler trace was analyzed offline. TR dP/dt was calculated using simplified Bernoulli equation (dP/dt between 1 and 2 m/sec). dP/dt/Vmax was calculated as a ratio of dP/dt and TR Vmax . RV end-diastolic (EDV) and end-systolic volumes (ESV) were obtained from contouring of steady-state-free precession axial stack CMR images; RVEF was calculated as [(RVEDV - RVESV)/RVEDV] × 100. RVEF >42% was considered normal. RESULTS: Majority of studies were suitable for analysis. Median age was 48 years (IQR = 36-63); 56.4% were female (n = 22/39). There was correlation between dP/dt and RVEF (r(2) = 0.51, P < 0.01) which improved with dP/dt/Vmax (r(2) = 0.59, P < 0.01). dP/dt >400 mmHg/sec had a positive predictive value of 91%, sensitivity and specificity of 74% and 84% respectively for normal RVEF. Inter-observer agreement and repeatability analysis showed no significant difference. CONCLUSION: Tricuspid dP/dt correlates well with CMR RVEF. A dP/dt of more than 400 mmHg/sec strongly predicts normal RVEF. Adjusting for preload (dP/dt/Vmax) further improves this correlation.

Effects of a culturally informed model of care for Aboriginal and Torres Strait Islander patients with acute coronary syndrome in a tertiary hospital in Australia: a pre-post, quasi-experimental, interventional study.

BACKGROUND: Aboriginal and Torres Strait Islander (Indigenous) peoples with cardiac disease in Australia have worse outcomes than non-Indigenous people with cardiac disease. We hypothesised that the implementation of a culturally informed model of care for Indigenous patients hospitalised with acute coronary syndrome (ACS) would improve their clinical outcomes. METHODS: For this pre-post, quasi-experimental, interventional study, cohorts of Indigenous patients before and after the implementation of a model of care were compared. The novel, culturally informed, multidisciplinary-team model of care was a local programme of care developed to reduce morbidity and mortality from cardiac conditions among Indigenous Australians. All index admissions in the 24-month pre-implementation period (Jan 1 2013, to Dec 31, 2014) were analysed, as were all index admissions in the 12-month post-implementation period (Oct 1, 2015, to Sept 30, 2016). Comparisons were also made with non-Indigenous cohorts in the same timeframes. Admissions were excluded if the patient did not survive to hospital discharge. The study was conducted at Princess Alexandra Hospital, a tertiary hospital in metropolitan Brisbane (QLD, Australia). Data on presentation, comorbidities, investigations, treatment, and for outcomes were manually collected from a consolidated clinical information application. Mortality data were obtained from the Queensland Registry of Births, Deaths, and Marriages. The primary outcome was a composite of death, acute myocardial infarction, unplanned revascularisation, and cardiac readmission at 90 days after index admission, assessed in all patients. FINDINGS: The Indigenous cohorts included 199 patients admitted with ACS before the model of care was implemented (85 [43%] were female and 114 [57%] were male) and 119 admitted post-implementation (62 [52%] were female and 57 [48%] were male). The non-Indigenous cohorts included 440 patients with ACS before the model of care was implemented (140 [32%] were female and 300 [68%] were male) and 467 admitted post-implementation (143 [31%] were female and 324 [69%] were male). Compared with the pre-implementation group, Indigenous patients admitted post-implementation had a significant reduction in the primary outcome (67 [34%] of 199 vs 24 [20%] of 119; hazard ratio 0·60, 95% CI 0·40-0·90; p=0·012), which was driven by a reduction in unplanned cardiac readmissions (64 [32%] of 199 vs 21 [18%] of 119; 0·55, 0·35-0·85; p=0·0060). There was no significant change in non-Indigenous patients between the pre-implementation and post-implementation timeframes in the composite endpoint at 90 days (81 [18%] of 440 vs 93 [20%] of 467; 1·08, 0·83-1·41; p=0·54). Pre-implementation, there was significantly more incidence of the primary outcome in Indigenous patients than non-Indigenous patients (p<0·0001), with no significant difference in the post-implementation period (p=0·92). INTERPRETATION: Clinical outcomes for Indigenous patients admitted to a tertiary hospital in Australia improved after implementation of a culturally informed model of care, with a reduction in the disparity in incidence of primary endpoints that existed between Indigenous and non-Indigenous patients before implementation. FUNDING: Queensland Department of Health Aboriginal and Torres Strait Islander Health Division (now First Nations Health Office).

The value of serial echocardiography in risk assessment of patients with paroxysmal atrial fibrillation.

Progression from paroxysmal to persistent atrial fibrillation (AF) is associated with increased morbidity and mortality. We examined the association of left atrial (LA) remodeling by serial echocardiography, and AF progression over an extended follow-up period. Two-hundred ninety patients (mean age 61  ±  11 years, 73% male) who underwent transthoracic echocardiography performed at first presentation for non-valvular paroxysmal AF (PAF) and repeat echocardiogram 1-year later, were followed for progression to persistent AF. LA and left ventricular (LV) dimensions, volumes, LA reservoir, conduit and booster pump strains, LV global longitudinal systolic strain (GLS) assessed by 2D speckle tracking, and PA-TDI (time delay between electrical and mechanical LA activation- reflecting the extent of LA fibrosis) were compared on serial echocardiography. Sixty-nine (24%) patients developed persistent AF over a mean follow-up period of 6.3 years. At baseline, patients with subsequent persistent AF had larger LA dimensions (46 mm vs. 42 mm, p < 0.001), indexed LA volumes (41 ml/m2 vs. 34 ml/m2, p < 0.001), lower LA reservoir and conduit strain (17.6% vs. 27.6%, p < 0.001; 10.5% vs. 16.3%, p < 0.001; respectively) and longer PA-TDI (155 ms vs. 132 ms, p < 0.001) compared to the PAF group. Patients with subsequent persistent AF showed over time significant enlargement in LA volumes (from 37.7 ml/m2 to 42.4 ml/m2, p < 0.001), lengthening of PA-TDI (from 142.2 ms to 162.2 ms, p = 0.002), and decline in LA reservoir function (from 21.9% to 18.1%, p = 0.024) after adjusting for age, gender, diabetes and LV GLS. There were no changes in LA diameter, LA conduit or booster pump function. Conversely, the PAF group showed no decline in LA function. Patients who developed persistent AF had larger LA size and impaired LA function and atrial conduction times at baseline, compared to patients who remained PAF. Over the 1-year time course of serial echocardiographic evaluation, there was progression of LA remodeling in patients who subsequently developed persistent AF, but not in patients who remained in PAF.

Effect of cardiac resynchronization therapy in patients without left intraventricular dyssynchrony.

AIMS: To evaluate the effects of cardiac resynchronization therapy (CRT) on long-term survival of patients without baseline left ventricular (LV) mechanical dyssynchrony. METHODS AND RESULTS: A total of 290 heart failure patients (age 67 ± 10 years, 77% males) without significant baseline LV dyssynchrony (<60 ms as assessed with tissue Doppler imaging) were treated with CRT. Patients were divided according to the median LV dyssynchrony measured after 48 h of CRT into two groups. All-cause mortality was compared between the subgroups. In addition, the all-cause mortality rates of these subgroups were compared with the all-cause mortality of 290 heart failure patients treated with CRT who showed significant LV dyssynchrony (≥60 ms) at baseline. In the group of patients without significant LV dyssynchrony, median LV dyssynchrony increased from 22 ms (inter-quartile range 16-34 ms) at baseline to 40 ms (24-56 ms) 48 h after CRT. The cumulative mortality rates at 1-, 2-, and 3-year follow-up of patients with LV dyssynchrony ≥40 ms 48 h after CRT implantation were significantly higher when compared with patients with LV dyssynchrony <40 ms (10, 17, and 23 vs. 3, 8, and 10%, respectively; log-rank P< 0.001). Finally, the cumulative mortality rates at 1-, 2-, and 3-year follow-up of patients with baseline LV dyssynchrony were 3, 8, and 11%, respectively (log-rank P= 0.375 vs. patients with LV dyssynchrony <40 ms). Induction of LV dyssynchrony after CRT was an independent predictor of mortality (hazard ratio: 1.247; P= 0.009). CONCLUSION: In patients without significant LV dyssynchrony, the induction of LV dyssynchrony after CRT may be related to a less favourable long-term outcome.

Cardiac "hypertrophy" phenotyping: differentiating aetiologies with increased left ventricular wall thickness on echocardiography.

Aims: Differentiating phenotypes of cardiac "hypertrophy" characterised by increased wall thickness on echocardiography is essential for management and prognostication. Transthoracic echocardiography is the most commonly used screening test for this purpose. We sought to identify echocardiographic markers that distinguish infiltrative and storage disorders that present with increased left ventricular (LV) wall thickness, namely, cardiac amyloidosis (CA) and Anderson-Fabry disease (AFD), from hypertensive heart disease (HHT). Methods: Patients were retrospectively recruited from Westmead Hospital, Sydney, and Princess Alexandra Hospital, Brisbane. LV structural, systolic, and diastolic function parameters, as well as global (LVGLS) and segmental longitudinal strains, were assessed. Previously reported echocardiographic parameters including relative apical sparing ratio (RAS), LV ejection fraction-to-strain ratio (EFSR), mass-to-strain ratio (MSR) and amyloidosis index (AMYLI) score (relative wall thickness × E/e') were evaluated. Results: A total of 209 patients {120 CA [58 transthyretin amyloidosis (ATTR) and 62 light-chain (AL) amyloidosis], 31 AFD and 58 HHT patients; mean age 64.1 ± 13.7 years, 75% male} comprised the study cohort. Echocardiographic measurements differed across the three groups, The LV mass index was higher in both CA {median 126.6 [interquartile range (IQR) 106.4-157.9 g/m2]} and AFD [median 134 (IQR 108.8-152.2 g/m2)] vs. HHT [median 92.7 (IQR 79.6-102.3 g/m2), p < 0.05]. LVGLS was lowest in CA [median 12.29 (IQR 10.33-15.56%)] followed by AFD [median 16.92 (IQR 14.14-18.78%)] then HHT [median 18.56 (IQR 17.51-19.97%), p < 0.05]. Diastolic function measurements including average e' and E/e' were most impaired in CA and least impaired in AFD. Indexed left atrial volume was highest in CA. EFSR and MSR differentiated secondary (CA + AFD) from HHT [receiver operating curve-area under the curve (ROC-AUC) of 0.80 and 0.91, respectively]. RAS and AMYLI score differentiated CA from AFD (ROC-AUC of 0.79 and 0.80, respectively). A linear discriminant analysis with stepwise variable selection using linear combinations of LV mass index, average e', LVGLS and basal strain correctly classified 79% of all cases. Conclusion: Simple echocardiographic parameters differentiate between different "hypertrophic" cardiac phenotypes. These have potential utility as a screening tool to guide further confirmatory testing.

Prevalence and Prognostic Implications of Moderate or Severe Mitral Regurgitation in Patients with Bicuspid Aortic Valve.

BACKGROUND: Significant (moderate or greater) mitral regurgitation (MR) could augment the hemodynamic effects of aortic valvular disease in patients with bicuspid aortic valve (BAV), imposing a greater hemodynamic burden on the left ventricle and atrium, possibly culminating in a faster onset of left ventricular dilation and/or symptoms. The aim of this study was to determine the prevalence and prognostic implications of significant MR in patients with BAV. METHODS: In this large, multicenter, international registry, a total of 2,932 patients (mean age, 48 ± 18 years; 71% men) with BAV were identified. All patients were evaluated for the presence of significant primary or secondary MR by transthoracic echocardiography and were followed up for the end points of all-cause mortality and event-free survival. RESULTS: Overall, 147 patients (5.0%) had significant primary (1.5%) or secondary (3.5%) MR. Significant MR was associated with all-cause mortality (hazard ratio [HR], 2.80; 95% CI, 1.91-4.11; P < .001) and reduced event-free survival (HR, 1.97; 95% CI, 1.58-2.46; P < .001) on univariable analysis. MR was not associated with all-cause mortality (adjusted HR, 1.33; 95% CI, 0.85-2.07; P = .21) or event-free survival (adjusted HR, 1.10; 95% CI, 0.85-1.42; P = .49) after multivariable adjustment. However, sensitivity analyses demonstrated that significant MR not due to aortic valve disease retained an independent association with mortality (adjusted HR, 1.81; 95% CI, 1.04-3.15; P = .037). Subgroup analyses demonstrated an independent association between significant MR and all-cause mortality for individuals with significant aortic regurgitation (HR, 2.037; 95% CI, 1.025-4.049; P = .042), although this association was not observed for subgroups with significant aortic stenosis or without significant aortic valve dysfunction. CONCLUSIONS: Significant MR is uncommon in patients with BAV. Following adjustment for important confounding variables, significant MR was not associated with adverse prognosis in this large study of patients with BAV, except for the patient subgroup with moderate to severe aortic regurgitation. In addition, significant MR not due to aortic valve disease demonstrated an independent association with all-cause mortality.

Influence of left ventricular geometry and function on aortic annular dimensions as assessed with multi-detector row computed tomography: implications for transcatheter aortic valve implantation.

AIMS: Evaluate changes in aortic annular dimensions in relation to severe aortic stenosis (AS) and left ventricular (LV) dysfunction. METHODS AND RESULTS: Mean aortic annular diameters and geometries were compared between 90 severe AS patients and 111 controls by multi-detector row computed tomography (MDCT). All severe AS patients were also dichotomized into two groups based on the presence of preserved (≥ 50%) or impaired (<50%) LV ejection fraction (EF). The influence of LV geometry and function on changes in aortic annular dimensions was examined. Patients with severe AS had similar aortic annular dimensions and geometries compared with controls even after correcting for baseline differences in age and body surface area (BSA). However, severe AS patients with LV dysfunction (LVEF <50%) had significantly larger mean aortic annular diameter (26.4 ± 1.9 vs. 24.5 ± 2.1 mm, P < 0.001) compared with patients with preserved LVEF. The presence of LV dysfunction, male gender, and larger BSA were independent determinants of a larger aortic annulus on MDCT. CONCLUSION: In severe AS patients, the presence of LV dysfunction, not the presence of severe AS, was an independent determinant of a larger aortic annular diameter.

Alterations in multidirectional myocardial functions in patients with aortic stenosis and preserved ejection fraction: a two-dimensional speckle tracking analysis.

AIMS: To identify changes in multidirectional strain and strain rate (SR) in patients with aortic stenosis (AS). METHODS AND RESULTS: A total of 420 patients (age 66.1 ± 14.5 years, 60.7% men) with aortic sclerosis, mild, moderate, and severe AS with preserved left ventricular (LV) ejection fraction [(EF), ≥50%] were included. Multidirectional strain and SR imaging were performed by two-dimensional speckle tracking. Patients were more likely to be older (P < 0.001) and at a worse New York Heart Association functional class (P < 0.001) with increasing AS severity. There was a progressive stepwise impairment in longitudinal, circumferential, and radial strain and SR with increasing AS severity (all P < 0.001). The myocardial dysfunction appeared to start in the subendocardium with mild AS, to mid-wall dysfunction with moderate AS, and eventually transmural dysfunction with severe AS. Aortic valve area, as a measure of AS severity, was an independent determinant of multidirectional strain and SR on multiple linear regressions. CONCLUSIONS: Patients with AS have evidence of subclinical myocardial dysfunction early in the disease process despite normal LVEF. The myocardial dysfunction appeared to start in the subendocardium and progressed to transmural dysfunction with increasing AS severity. Symptomatic moderate and severe AS patients had more impaired multidirectional myocardial functions compared with asymptomatic patients.