Manifestations of Prosthetic Valve Endocarditis: Lessons From Multimodality Imaging and Pathological Correlation.

Heart valve replacement has steadily increased over the past decades due to improved surgical mortality, an aging population, and the increasing use of transcatheter valve technology. With these developments, prosthetic valve complications, including prosthetic valve endocarditis, are increasingly encountered. In this review, we aim to characterize the manifestations of prosthetic valve endocarditis using representative case studies from our institution to highlight the advances and contributions of modern multimodality imaging techniques.

Patient-Prosthesis Mismatch After Surgical Aortic Valve Replacement: Analysis of the PARTNER Trials.

BACKGROUND: Our objective was to compare the impact of patient-prosthesis mismatch (PPM) for 2 years after surgical aortic valve replacement within the prospective, randomized Placement of Aortic Transcatheter Valves (PARTNER) trials. METHODS: Surgical aortic valve replacement patients from the PARTNER 1, 2, and 3 trials were included. PPM was classified as moderate (indexed effective orifice area ≤0.85 cm2/m2) or severe (indexed effective orifice area ≤0.65 cm2/m2). The primary endpoint was the composite of all-cause death and heart failure rehospitalization at 2 years. RESULTS: By the predicted PPM method (PPMP), 59.1% had no PPM, 38.8% moderate PPM, and 2.1% severe PPM; whereas by the measured PPM method (PPMM), 42.4% had no PPM, 36.0% moderate, and 21.6% severe. Patients with no PPMP (23.6%) had a lower rate of the primary endpoint compared with patients with moderate (28.2%, P = .03) or severe PPMP (38.8%, P = .02). Using the PPMM method, there was no difference between the no (17.7%) and moderate PPMM groups (21.1%) in the primary outcome (P = .16). However, those with no PPMM or moderate PPMM were improved compared with severe PPMM (27.4%, P < .001 and P = .02, respectively). CONCLUSIONS: Severe PPM analyzed by PPMP was only 2.1% for surgical aortic valve replacement patients. The PPMM method overestimated the incidence of severe PPM relative to PPMP, but was also associated with worse outcome. There was higher all-cause mortality in patients with severe PPM, thus surgical techniques to minimize PPM remain critical.

Frequency of screening for cardiac allograft vasculopathy: warranty period of initial low risk positron emission tomography.

AIMS: The short-term risk of moderate-severe cardiac allograft vasculopathy (CAV) after a low-risk positron emission tomography/computed tomography (PET/CT) is unknown, and therefore, there is no guidance on how frequently to perform screening. The aim of this study was to assess the rate of progression to moderate-severe CAV as part of an annual screening programme. METHODS AND RESULTS: Patients with no history of CAV 2/3 and a low-risk result on initial screening PET/CT (CAV 0/1) were enrolled in the study. The primary outcome was the progression to CAV 2/3 as part of an annual screening programme (within 6-18 months of initial scan). PET CAV results were graded according to a published and externally validated diagnostic criterion for CAV. Over the study period, 231 patients underwent an initial PET/CT and had a subsequent evaluation for CAV. In this cohort, 4.3% of patients progressed to CAV 2/3 at a median of 374 days (interquartile range 363-433). Initial PET CAV grade was the most significant patient characteristic associated with the progression of CAV, with 17% of patients with PET CAV 1 progressing to CAV 2/3 compared with 1.6% with PET CAV 0 (odds ratio 12.4, 95% confidence interval 3.06-50.3). CONCLUSION: The rate of progression to moderate-severe CAV at 1 year after the lowest-risk PET/CT is low, but approximately 1/6 patients with PET CAV 1 progress to CAV 2/3. Annual screening with PET/CT for select patients with PET CAV 0 may not be warranted. The optimal screening interval awaits confirmation of our findings in multi-centre registries.

Changes in Left Ventricular Ejection Fraction and Clinical Trajectories of Transthyretin Cardiac Amyloidosis with Systolic Dysfunction.

BACKGROUND: Transthyretin cardiac amyloidosis (ATTR-CM) is classically thought of as a progressive disease with preserved systolic function. The longitudinal clinical trajectories of ATTR-CM with impaired left ventricular ejection fraction (LVEF) remain unclear. METHODS: This is a single-center retrospective cohort study of consecutive patients with ATTR-CM who underwent two or more echocardiograms with baseline LVEF < 50%. Patients were stratified according to the presence of ≥5% change in LVEF. A Cox proportional hazard model examined hazard of a composite outcome of death, transplant, or LVAD insertion over the two years following diagnosis. RESULTS: In our study cohort of 179 patients, 62 patients (34.6%) experienced an increase in LVEF while 33 (18.4%) experienced a decrease in LVEF. After adjusting for covariates, patients with a decrease in EF experienced increased hazard of death (HR 2.15, 95% CI 1.05-4.40, p = 0.038) compared to those with stable or an increase in LVEF. Changes in LVEF corresponded with significant differences in NT proBNP trajectories, but initial biomarker levels or clinical staging were not predictive of LVEF trajectory. CONCLUSIONS: in ATTR-CM patients with impaired LVEF, over a third demonstrated improved LVEF over time, while those with a decrease in LVEF had worse long-term outcomes.

Optimal left ventricular ejection fraction in risk stratification of patients with cardiac sarcoidosis.

AIMS: Identifying patients with cardiac sarcoidosis (CS) who are at an increased risk of sudden cardiac death (SCD) poses a clinical challenge. We sought to identify the optimal cutoff for left ventricular ejection fraction (LVEF) in predicting ventricular arrhythmia (VA) and all-cause mortality and to identify clinical and imaging risk factors in patients with known CS. METHODS AND RESULTS: This retrospective cohort included 273 patients with well-established CS. The primary endpoint was a composite of VA and all-cause mortality. A modified receiver operating curve analysis was utilized to identify the optimal cutoff for LVEF in predicting the primary composite endpoint. Cox proportional hazard regression analysis was used to identify independent risk factors of the outcomes. At median follow-up of 7.9 years, the rate of the primary endpoint was 38% (83 VAs and 32 all-cause deaths). The 5-year overall survival rate was 97%. The optimal cutoff LVEF for the primary composite endpoint was 42% in the entire cohort and in subjects without a history of VA. Younger age, history of VA, lower LVEF, and any presence of scar by cardiac magnetic resonance (CMR) imaging and/or positron emission tomography (PET) were found to be independent risk factors for the primary endpoint and for VA, whereas lower LVEF, baseline NT-proBNP, and any presence of scar were independent risk factor of all-cause mortality. CONCLUSION: Among patients with CS, a mild reduction in LVEF of 42% was identified as the optimal cutoff for predicting VA and all-cause mortality. Prior VA and scar by CMR or PET are strong risk factors for future VA and all-cause mortality.

Enhanced Thromboresistance and Endothelialization of a Novel Fluoropolymer-Coated Left Atrial Appendage Closure Device.

BACKGROUND: Device-related thrombus (DRT) after left atrial appendage closure (LAAC) procedures is a rare but potentially serious event. Thrombogenicity and delayed endothelialization play a role in the development of DRT. Fluorinated polymers are known to have thromboresistant properties that may favorably modulate the healing response to an LAAC device. OBJECTIVES: The goal of this study was to compare the thrombogenicity and endothelial coverage (EC) after LAAC between the conventional uncoated WATCHMAN FLX (WM) and a novel fluoropolymer-coated WATCHMAN FLX (FP-WM). METHODS: Canines were randomized for implantation with WM or FP-WM devices and given no postimplant antithrombotic/antiplatelet agents. The presence of DRT was monitored by using transesophageal echocardiography and verified histologically. The biochemical mechanisms associated with coating were assessed by using flow loop experiments to quantify albumin adsorption, platelet adhesion, and porcine implants to quantify EC and the expression of markers of endothelial maturation (ie, vascular endothelial-cadherin/p120-catenin). RESULTS: Canines implanted with FP-WM exhibited significantly less DRT at 45 days than those implanted with WM (0% vs 50%; P < 0.05). In vitro experiments showed significantly greater albumin adsorption (52.8 [IQR: 41.0-58.3] mm2 vs 20.6 [IQR: 17.2-26.6] mm2; P = 0.03) and significantly less platelet adhesion (44.7% [IQR: 27.2%-60.2%] vs 60.9% [IQR: 39.9%-70.1%]; P < 0.01) on FP-WM. Porcine implants showed significantly greater EC by scanning electron microscopy (87.7% [IQR: 83.4%-92.3%] vs 68.2% [IQR: 47.6%-72.8%]; P = 0.03), and higher vascular endothelial-cadherin/p120-catenin expression after 3 months on FP-WM compared with WM. CONCLUSIONS: The FP-WM device showed significantly less thrombus and reduced inflammation in a challenging canine model. Mechanistic studies indicated that the fluoropolymer-coated device binds more albumin, leading to reduced platelet binding, less inflammation, and greater EC.

Modern tools in cardiac imaging to assess myocardial inflammation and infection.

Myocardial forms of infection and inflammation are highly heterogeneous in clinical course and presentation but associated with diagnostic and treatment uncertainty, high morbidity, mortality, and financial burden. Historically, these pathologies were diagnosed invasively with biopsy, surgical pathology, or explanted hearts. However, in the current era, the diagnosis has been aided by a variety of non-invasive imaging tools in the appropriate clinical presentation. This review provides a comprehensive understanding of the available imaging modalities for guiding the diagnosis, treatment, and prognosis of cardiac infection and inflammation.

Anticoagulation after pulmonary vein isolation for atrial fibrillation: Associations with CHA2DS2-VASc score, sex, and rhythm.

Guidelines recommend using the CHA2DS2-VASc score to determine anticoagulation decisions in atrial fibrillation (AF) patients, including those who undergo pulmonary vein isolation (PVI), however this may not consistently occur in the real-world setting because of other clinical factors. We sought to evaluate the anticoagulation prescription rates patterns in AF patients 1 year PVI at our institution. Consecutive AF patients undergoing PVI in our prospective registry during 2014-2018 who were alive at 1-year post-PVI were studied. Anticoagulation prescription rates at this time-point were adjudicated, and correlated to CHA2DS2-VASc score, sex, and heart rhythm status at 1 year. Amongst 4596 patients undergoing PVI, mean age was 64.2 ± 10.0 years, 1328 (28.9%) were female, and based on CHA2DS2-VASc score anticoagulation was not indicated, can be considered and indicated in 872 (19.0%), 1183 (25.7%), and 2541 (55.3%) patients, respectively. At 1-year after PVI, 3504 (76.2%) patients were on anticoagulation, and 792 (17.2%) had recurrence of AF. Anticoagulation was continued in over half of AF patients without classic CHA2DS2-VASc indication particularly in those with AF recurrence and women, while they were mildly under-prescribed in those with indication, especially for those without AF recurrence and men. In a large real world cohort of patients after PVI, anticoagulation prescription is not solely depending on the CHA2DS2-VASc score and sex, but also heart rhythm status and other clinical or imaging factors.

Negative Predictive Value and Prognostic Associations of Rb-82 PET/CT with Myocardial Blood Flow in CAV.

BACKGROUND: Invasive coronary angiography (ICA) is the traditional screening modality for cardiac allograft vasculopathy (CAV). Positron emission tomography/computed tomography (PET/CT) scan with myocardial blood flow (MBF) quantification has emerged as a potential noninvasive alternative. OBJECTIVES: The aim of the study was to validate the diagnostic and prognostic value of a previously published algorithm for diagnosing CAV via PET/CT scans with MBF in a larger population. The study also sought to assess the downstream use of ICA when using PET/CT scanning as a screening modality. METHODS: Patients with heart transplantation without prior revascularization who underwent PET/CT scans with MBF were identified retrospectively. The accuracy of the algorithm was assessed in patients who underwent PET/CT scanning within 1 year of ICA. The prognostic value was assessed via a composite outcome of heart failure hospitalization, myocardial infarction, retransplantation, and all-cause mortality. RESULTS: A total of 88 patients for the diagnostic portion and 401 patients for the prognostic portion were included. PET CAV 0 had high negative predictive value for moderate to severe CAV (97%) and PET CAV 2/3 had a high positive predictive value for moderate to severe CAV (68%) by ICA. The cohort was followed for a median of 1.2 (IQR: 1.0-1.8) years with 46 patients having an adverse event. The annualized event rates were 6.9%, 9.3%, and 30.8% for PET CAV 0, 1, and 2/3, respectively (P < 0.001). CONCLUSIONS: An algorithm using PET/CT scanning with MBF demonstrates high a negative predictive value for CAV. PET CAV 2/3 is associated with a higher risk of adverse events and need for revascularization. PET/CT scanning with MBF is a reasonable alternative to ICA for screening for CAV.

Clinical and Echocardiographic Characteristics of Flow-Based Classification Following Balloon-Expandable Transcatheter Heart Valve in PARTNER Trials.

BACKGROUND: Current expected normal echocardiographic measures of transcatheter heart valve (THV) function were derived from pooled cohorts of the randomized trials; however, THV function by flow state before or following transcatheter aortic valve replacement (TAVR) has not been previously reported. OBJECTIVES: This study sought to assess the expected normal echocardiographic hemodynamics for the balloon-expandable THV grouped by stroke volume index (SVI). METHODS: Patients with severe aortic stenosis enrolled in PARTNER (Placement of Aortic Transcatheter Valves) 1 (high/extreme surgical risk), PARTNER 2 (intermediate surgical risk), or PARTNER 3 (low surgical risk) trials with complete core laboratory echocardiography were included. Patients were grouped by low-flow (SVILOW <35 mL/m2) and normal-flow (SVINORMAL ≥35 mL/m2). Mean gradient, effective orifice area (EOA), and Doppler velocity index (DVI) were collected at baseline and at 30 days post-TAVR. Prosthesis-patient mismatch (PPM) was both calculated and predicted from normative data, using defined criteria. RESULTS: In the entire population (N = 4,991), mean age was 81.8 years, 58% of patients were male, and 42% had low flow. Compared with patients with baseline SVINORMAL, those with SVILOW were more likely to be male; have more comorbidities; and lower left ventricular ejection fraction, mean gradient, and EOA. Post-TAVR, SVILOW increased to SVINORMAL in 17.3% and SVINORMAL decreased to SVILOW in 12.3% of patients. Using baseline SVI, follow-up EOA, mean gradient, and DVI for patients with SVILOW tended to be lower than for patients with SVINORMAL. Using the post-TAVR SVI, follow-up EOA, mean gradient, and DVI were significantly lower for patients with SVILOW than for those with SVINORMAL (P < 0.001 for all). The incidence of calculated, but not predicted, severe PPM was higher in patients with low flow than it was in patients with normal flow, suggesting pseudo-PPM in the presence of low flow. CONCLUSIONS: This study demonstrates that flow affects THV hemodynamics and both baseline and follow-up SVI should be considered when predicting THV hemodynamics prior to TAVR, as well as assessing valve function following valve implantation.

Utility of nuclear cardiovascular imaging in the cardiac intensive care unit.

The contemporary Cardiac Intensive Care Unit (CICU) has evolved into a complex unit that admits a heterogeneous mix of patients with a wide range of acute cardiovascular diseases often complicated by multi-organ failure. Although electrocardiography (ECG) and echocardiography are well-established as first-line diagnostic modalities for assessing patients in the CICU, nuclear cardiology imaging has emerged as a useful adjunctive diagnostic modality. The versatility, safety and accuracy of nuclear imaging (e.g., perfusion, metabolism, inflammation) for the assessment of patient with coronary artery disease, ventricular arrhythmias, infiltrative cardiomyopathies, infective endocarditis and inflammatory aortopathies has been proven useful and now often incorporated into the best practices for the management of critically ill cardiac patients. Thus, clinicians must familiarize themselves with the value and current and future applications of nuclear imaging in the management of the cardiac patient in the CICU.