Appleton, Christopher P.

Background: The progression of CHF after MI has been traditionally evaluated by serial changes in EF. However, mechanical parameters can provide a greater insight into cardiac function. Wall strain measures myocardial deformation, and reflects contractile function as a percentage change in length. Wall stress represents the force per unit area on the myocardium, as an evaluation of LV afterload. The relationship between wall stress and wall strain is termed Young’s modulus, and it represents cardiac elasticity. This study leverages in-vivo Young’s modulus analysis derived from cardiac MRI, which has the potential to quantify the extent of myocardial remodeling, and aid in early detection of heart failure progression. Hypothesis: We hypothesize that Young’s modulus offers a more detailed assessment of regional wall motion abnormality than conventional imaging measures alone. Methods: Male Yucatan mini-swine underwent 90-minute balloon occlusion-reperfusion of the left anterior descending coronary artery to induce MI (N=13). Cardiac MRIs were obtained at baseline and 1-month post-MI. Cardiac wall stress and wall strain were calculated separately in the anteroseptal (infarcted) and inferolateral (non-infarcted) regions, and in the longitudinal and circumferential fiber orientations. These measurements were correlated to determine the Young’s modulus of the LV. Results: Anteroseptal and inferolateral longitudinal Young’s modulus increased from 28.01±8.14 to 67.14±15.08 kPa (p < 0.05) from 13.88±1.92 to 38.80±7.29 kPa (p < 0.001), respectively. Anteroseptal and inferolateral circumferential Young’s modulus increased from 34.61±10.33 to 119.17±30.94 kPa (p < 0.05) and from 16.77±1.32 to 58.76±18.98 kPa (p < 0.001), respectively. The regional changes were accompanied by a decrease in EF from 60.6±1.5 to 50.9±3.3% (p < 0.01). Discussion: Our findings show that Young’s modulus is a valuable parameter in quantifying regional changes that occur with LV systolic dysfunction after ischemic insult; specifically that regional abnormalities occur in the non-infarcted area as well as the infarcted area––a change that would not be picked up by global LV EF. Thus, quantifying regional and directional cardiac elasticity non-invasively is a novel parameter that warrants further study. Prior research has explored the in-vitro characteristics of cardiac elasticity, but there is limited research that details the in-vivo changes within any disease affecting myocardial fiber contractility.

Background: Post-transcatheter aortic valve replacement (TAVR) patient outcome is an important research topic. To accurately assess post-TAVR mortality, we examined a family of new echo parameters (augmented systolic blood pressure (AugSBP) and arterial mean pressure (AugMAP)) derived from blood pressure and aortic valve gradients. Methods: Patients in the Mayo Clinic National Cardiovascular Diseases Registry-TAVR database who underwent TAVR between 1 January 2012 and 30 June 2017 were identified to retrieve baseline clinical, echocardiographic and mortality data. AugSBP, AugMAP and valvulo-arterial impedance (Zva) (Zva) were evaluated using Cox regression. Receiver operating characteristic curve analysis and the c-index were used to assess the model performance against the Society of Thoracic Surgeons (STS) risk score. Results: The final cohort contained 974 patients with a mean age of 81.4 ± 8.3 years old, and 56.6% were male. The mean STS risk score was 8.2 ± 5.2. The median follow-up duration was 354 days, and the one-year all-cause mortality rate was 14.2%. Both univariate and multivariate Cox regression showed that AugSBP and AugMAP parameters were independent predictors for intermediate-term post-TAVR mortality (all p < 0.0001). AugMAP1 < 102.5 mmHg was associated with a 3-fold-increased risk of all-cause mortality 1-year post-TAVR (hazard ratio 3.0, 95%confidence interval 2.0–4.5, p < 0.0001). A univariate model of AugMAP1 surpassed the STS score model in predicting intermediate-term post-TAVR mortality (area under the curve: 0.700 vs. 0.587, p = 0.005; c-index: 0.681 vs. 0.585, p = 0.001). Conclusions: Augmented mean arterial pressure provides clinicians with a simple but effective approach to quickly identify patients at risk and potentially improve post-TAVR prognosis.

Aims:Increased left ventricular (LV) wall thickness is frequently encountered in transthoracic echocardiography (TTE). While accurate and early diagnosis is clinically important, given the differences in available therapeutic options and prognosis, an extensive workup is often required to establish the diagnosis. We propose the first echo-based, automated deep learning model with a fusion architecture to facilitate the evaluation and diagnosis of increased left ventricular (LV) wall thickness. Methods and Results: Patients with an established diagnosis of increased LV wall thickness (hypertrophic cardiomyopathy (HCM), cardiac amyloidosis (CA), and hypertensive heart disease (HTN)/others) between 1/2015 and 11/2019 at Mayo Clinic Arizona were identified. The cohort was divided into 80%/10%/10% for training, validation, and testing sets, respectively. Six baseline TTE views were used to optimize a pre-trained InceptionResnetV2 model. Each model output was used to train a meta-learner under a fusion architecture. Model performance was assessed by multiclass area under the receiver operating characteristic curve (AUROC). A total of 586 patients were used for the final analysis (194 HCM, 201 CA, and 191 HTN/others). The mean age was 55.0 years, and 57.8% were male. Among the individual view-dependent models, the apical 4-chamber model had the best performance (AUROC: HCM: 0.94, CA: 0.73, and HTN/other: 0.87). The final fusion model outperformed all the view-dependent models (AUROC: HCM: 0.93, CA: 0.90, and HTN/other: 0.92). Conclusion: The echo-based InceptionResnetV2 fusion model can accurately classify the main etiologies of increased LV wall thickness and can facilitate the process of diagnosis and workup.

Background: Pectus excavatum (PE) deformity involves posterior depression of the sternum and adjacent costal cartilages. The relationship of CT/MRI chest cardiac compression indices used as indications for surgical repair of PE with echocardiographic findings and with improvement in cardiac chamber compression and function post PE repair is unknown. Methods: We evaluated right atrial (RA) size, tricuspid annulus (TA size, right ventricular (RV) outflow tract size as well as RV 2D strain on intra-operative trans-esophageal echocardiography (TEE) immediately pre and post surgical PE repair. Inspiratory and expiratory Haller Index (HI) and cardiac compression indices (CCI) were measured on pre op CT/MR scans (Figure). Offline measurement of chamber dimensions on TEE images was performed and Speckle tracking strain measurements were made using Syngo US Workplace software (Siemens). P<0.05 was considered significant. Results: 60 patients, 73% male, 27% female, age 33.6±10.3 yrs underwent PE repair following CT/MRI from 2010-2014 (Figure). There was a strong correlation between expiratory CT/MRI chest AP diameter and pre-op RA size (panel A). Pre op RA and TA compression on TEE inversely correlated with pre op RV global longitudinal strain rate(RVGLSR) (panels B & C). CCI predicted improvement in RA size post PE repair (panels D & E). In addition pre op RA size on TEE correlated with improvement in RVGLSR post PE repair surgery (panel F). Conclusion: In patients with PE deformity, pre surgical CCI correlated with right-sided cardiac chamber compression on pre op TEE. Severity of chest and cardiac compression also predicted magnitude of improvement in right-sided chamber size and RV longitudinal deformation post PE repair. Our findings provide insight regarding the beneficial effects of PE surgery on right heart chamber compression and improvement in RV function and the important role of intraoperative TEE for patients undergoing PE repair surgery.

BackgroundThe development of a left ventricular (LV) apical pouch in patients with apical hypertrophic cardiomyopathy (aHCM) has been thought to be the transition point that can become an apical aneurysm, which is linked to higher risk of adverse events. In our study, we sought to compare the ability of transthoracic echocardiography (echo) and cardiac magnetic resonance imaging (cMRI) to accurately identify the presence of an apical pouch or aneurysm in patients with aHCM.MethodsWe retrospectively reviewed the charts of all consecutive patients that had features of aHCM on imaging. Data from cMRI and echo examinations were abstracted, and the ability of these diagnostic modalities to identify the presence of a LV apical pouch and aneurysm was analyzed.ResultsOf 31 patients with aHCM, 17 (54.8%) had an apical pouch and 2 were found to have apical aneurysm (6.5%) on cMRI. Echo with and without perflutren contrast was able to accurately identify both aneurysms, but only 47.1% (8/17) of apical pouches seen by cMRI. Two patients had apical thrombus that was identified by cMRI, but not by echo.ConclusionOur findings indicate that cMRI is superior to echo in identifying apical pouches in patients with aHCM. Our results also suggest that in patients undergoing echo, the use of perflutren contrast for LV opacification increases the diagnostic yield. Further study is necessary to delineate whether earlier identification of an apical pouch will be of clinical benefit for patients with aHCM by altering clinical management and avoiding adverse cardiovascular events.

Background Respiratory variation of ≥25% in mitral E velocity is a characteristic Doppler echocardiographic feature in constrictive pericarditis. However, a subset of patients with constriction do not exhibit the typical respiratory change, most likely because of marked increase in the left atrial pressure, and preload reduction may unmask the respiratory variation. Methods and Results In 12 patients with surgically confirmed constrictive pericarditis who had <25% respiratory variation in mitral E velocity during an initial preoperative examination, the Doppler study was repeated after an attempt to decrease left ventricular filling pressure. At baseline, mean mitral E velocity was similar after inspiration and expiration (0.81±0.24 and 0.84±0.21 m/s, respectively). On repeat Doppler examination, with the patient in a head-up tilt or sitting position, the decrease in mitral E velocity with inspiration (0.61±0.13 m/s) was significant ( P <.004), whereas it did not change significantly with expiration. The mean percent respiratory change in E velocity was 5±7% at baseline and 32±28% with preload reduction. Eight (75%) of the 12 patients developed respiratory variation of ≥25%. Conclusions When the respiratory variation in Doppler mitral E velocity is blunted or absent during the evaluation of suspected constrictive pericarditis, repeat Doppler recording of mitral flow velocities after maneuvers to decrease preload is recommended to unmask the characteristic respiratory variation in mitral E velocity.

Background Conventional cardiac catheterization criteria for the diagnosis of constrictive pericarditis (CP) rely on equalization of intracardiac pressures and have many recognized limitations. Recently, Doppler echocardiographic methods have been used to examine dynamic respiratory changes of increased ventricular interdependence and dissociation of intrathoracic and intracardiac pressures for the diagnosis of CP. These pathophysiological features may be best delineated by cardiac catheterization. Therefore, we studied the accuracy of these dynamic respiratory changes in left ventricular and right ventricular pressure for the diagnosis of CP at cardiac catheterization. Methods and Results High-fidelity manometric catheters and respirometry were used to study 36 patients: 15 patients with surgically proven CP (group 1) and 21 patients with other causes of heart failure (group 2). Conventional cardiac catheterization variables used to establish the diagnosis of CP lacked sensitivity and specificity and failed to distinguish between these groups. However, the finding of discordance between right ventricular and left ventricular pressures during inspiration, a sign of increased ventricular interdependence, accurately distinguished patients in group 1 from those in group 2 ( P <.05). Conclusions Examination of dynamic respiratory changes indicating increased ventricular interdependence may be helpful in the diagnosis of CP in the cardiac catheterization laboratory.

Objectives. To determine the importance of acute cardiac events as a cause of mortality compared to non-cardiac events in the four month period following liver transplantation (LT) using current preoperative cardiac screening strategies.Patients and Methods. We retrospectively reviewed timing, type, and outcome of adverse cardiac events, and all cause mortality in the 4 month postoperative period in 393 consecutive LT patients from October 1999 to February 2008.Results. Of 30 total deaths (7.6% overall mortality rate), 27 (90%) were due to surgical or medical complications and 3 (10%) were primary cardiac deaths (0.8% cardiac mortality rate). Acute cardiac events occurred in 26 patients (6.6%), including 13 arrhythmias (50%), 7 new onset heart failures (27%), and 6 myocardial infarctions (23%). Twelve of 13 intraoperative events were arrhythmias (92%) including two of three cardiac deaths.Conclusions. Using current preoperative screening recommendations, deaths from primary cardiac events within four months of LT are very uncommon (0.8%), especially compared with deaths related to medical and surgical complications (6.9%).