Improvement in cardiac function and regional LV strain following intramyocardial injection of a theranostic hydrogel early postmyocardial infarction in a porcine model.

Myocardial infarction (MI) is often complicated by left ventricular (LV) remodeling and heart failure. We evaluated the feasibility of a multimodality imaging approach to guide delivery of an imageable hydrogel and assessed LV functional changes with therapy. Yorkshire pigs underwent surgical occlusions of branches of the left anterior descending and/or circumflex artery to create an anterolateral MI. We evaluated the hemodynamic and mechanical effects of intramyocardial delivery of an imageable hydrogel in the central infarct area (Hydrogel group, n = 8) and a Control group (n = 5) early post-MI. LV and aortic pressure and ECG were measured and contrast cineCT angiography was performed at baseline, 60 min post-MI, and 90 min post-hydrogel delivery. LV hemodynamic indices, pressure-volume measures, and normalized regional and global strains were measured and compared. Both Control and Hydrogel groups demonstrated a decline in heart rate, LV pressure, stroke volume, ejection fraction, and pressure-volume loop area, and an increase in myocardial performance (Tei) index and supply/demand (S/D) ratio. After hydrogel delivery, Tei index and S/D ratio were reduced to baseline levels, diastolic and systolic functional indices either stabilized or improved, and radial strain and circumferential strain increased significantly in the MI regions (ENrr: +52.7%, ENcc: +44.1%). However, the Control group demonstrated a progressive decline in all functional indices to levels significantly below those of Hydrogel group. Thus, acute intramyocardial delivery of a novel imageable hydrogel to MI region resulted in rapid stabilization or improvement in LV hemodynamics and function.NEW & NOTEWORTHY Our study demonstrates that contrast cineCT imaging can be used to evaluate the acute effects of intramyocardial delivery of a therapeutic hydrogel to the central MI region early post MI, which resulted in a rapid stabilization of LV hemodynamics and improvement in regional and global LV function.

Co-attention spatial transformer network for unsupervised motion tracking and cardiac strain analysis in 3D echocardiography.

Myocardial ischemia/infarction causes wall-motion abnormalities in the left ventricle. Therefore, reliable motion estimation and strain analysis using 3D+time echocardiography for localization and characterization of myocardial injury is valuable for early detection and targeted interventions. Previous unsupervised cardiac motion tracking methods rely on heavily-weighted regularization functions to smooth out the noisy displacement fields in echocardiography. In this work, we present a Co-Attention Spatial Transformer Network (STN) for improved motion tracking and strain analysis in 3D echocardiography. Co-Attention STN aims to extract inter-frame dependent features between frames to improve the motion tracking in otherwise noisy 3D echocardiography images. We also propose a novel temporal constraint to further regularize the motion field to produce smooth and realistic cardiac displacement paths over time without prior assumptions on cardiac motion. Our experimental results on both synthetic and in vivo 3D echocardiography datasets demonstrate that our Co-Attention STN provides superior performance compared to existing methods. Strain analysis from Co-Attention STNs also correspond well with the matched SPECT perfusion maps, demonstrating the clinical utility for using 3D echocardiography for infarct localization.

Massive Air Embolism Following Necrotizing Pancreatitis and COVID-19 Infection-The Role of Postmortem Computed Tomography.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that caused the COVID-19 pandemic raised important questions about workplace exposures to the virus, including postmortem exposures. The complexity of COVID-19 disease and its numerous unanticipated complications made autopsy even more vital in determining the pathophysiology of the disease. Performing traditional autopsy, however, carries risk of exposure. The following report describes an unusual case in which a patient diagnosed with COVID-19 and necrotizing pancreatitis underwent postmortem computed tomography (PMCT) prior to limited traditional autopsy and was unexpectedly found via PMCT to have large and diffuse venous air emboli and a new peripancreatic hematoma. In this case, not only did PMCT play a crucial role in determining the cause of death but also it allowed for a limited autopsy, thereby reducing the exposure to SARS-CoV-2 and associated risk to the autopsy staff and pathologists.

Heart and kidney transplant: should they be combined or subsequent?

AIMS: End-stage heart failure patients often present with severe kidney failure and have limited treatment options. We compared the clinical characteristics and outcomes among end-stage heart and kidney failure patients who underwent combined heart and kidney transplant (HKTx) with those who underwent kidney transplant after heart transplant (KAH). METHODS AND RESULTS: All patients from 2007-2016 who underwent combined HKTx (n = 715) and those who underwent KAH (n = 130) using the United Network for Organ Sharing database were included. Kaplan-Meier curves and Cox models compared survivals and identified predictors of death. Number of combined HKTx performed annually in United States increased from 59 in 2007 to 146 in 2016 whereas KAH decreased from 34 in 2007 to 6 in 2016. Among KAH patients, average wait time for kidney transplant was 3.0 years, time to dialysis or to kidney transplant after heart transplant did not differ with varying severity of kidney disease at baseline (P for both >0.05). Upon follow-up (mean 3.5 ± 2.7 years), 151 patients died. In multivariable models, patients who underwent combined HKTx had 4.7-fold greater risk of death [95% confidence interval (CI) 2.4-9.4) than KAH patients upon follow up. A secondary analysis using calculation of survival only after kidney transplant for KAH patients still conferred higher risk for combined HKTx patients [hazard ratio (HR) 2.6 95% CI 1.33-5.15]. In subgroup analyses after excluding patients on dialysis (HR 3.99 95% CI 1.98-8.04) and analysis after propensity matching for age, gender, and glomerular filtration rate (HR 3.01 95% CI 1.40-6.43) showed similar and significantly higher risk for combined HKTx patients compared with KAH patients. Lastly, these results also remained unchanged after excluding transplant centres who performed only one type of procedure preferentially, i.e. HKTx or KAH (HR 4.70 95% CI 2.35-9.42). CONCLUSIONS: National registry data show continual increase in combined HKTx performed annually in the United States but inferior survival compared with KAH patients. Differences in patient characteristics or level of kidney dysfunction at baseline do not explain these poor outcomes among HKTx patients compared with KAH patients. Consensus guidelines are greatly needed to identify patients who may benefit more from dual organ transplants.

[Results of operations for ascending aortic aneurysm in Iceland 2000-2014].

INTRODUCTION: Thoracic aortic aneurysm (TAA) is an uncommon disease where treatment is complex and associated with significant comorbidity. The main aim of this study was to evaluate the outcomes of operations for TAA in Iceland with emphasis on postoperative complications, 30 day mortality and survival. MATERIALS AND METHODS: A retrospective study on 105 patients (mean age 60.7 yrs., 69.5% males) that underwent operations for TAA between 2000 and 2014 in Iceland. Patients with aortic injury or acute aortic dissection were excluded. Clinical information was collected from hospital charts and long-term survival estimated by Kaplan-Meier method. Mean follow-up was 5.7 yrs. RESULTS: Bicuspid aortic valve was present in 52 patients (51.0%) and family history was positive in 10 of the cases (9.5%). Every other patient (50.5%) was asymptomatic and diagnosed incidentally. The most common procedure was aortic root replacement using biological prosthesis. Two out of three patients had complications, that were regarded as major in 31.4% of cases, however, stroke was only detected in 2 (1.9%) patients. Two patients died within 30 days postoperatively (1.9%). The overall survival at one year was 95.1%; more favorable for males compared to females (97.2 vs. 90.4%, p=0.0012, log rank test) and at 5 years 90.3%. CONCLUSIONS: Outcome following surgery for TAA in Iceland is comparable to studies in neighbouring countries. The complications rate is high, however, the stroke rate was low, as was 30 day mortality. Longterm survival is favorable, and is more favorable for males than females. Key words: Thoracic aortic aneurysm, ascending aorta, open heart surgery, complications, operative mortality, survival. Correspondance: Arnar Geirsson, arnarge@landspitali.is.

The incidence and mortality of acute thoracic aortic dissection: results from a whole nation study.

OBJECTIVES: Acute thoracic aortic dissection (ATAD) is a devastating condition associated with a high mortality rate. Recent reports suggest that its incidence is rising. Utilizing nationwide data comprising the whole Icelandic population, we aimed to determine the incidence, mortality rate and time-dependent mortality risk of ATAD. METHODS: Data were retrospectively collected using centralized hospital discharge registries, autopsy records and Cause of Death Registry in Iceland from 1992 to 2013. RESULTS: Age- and gender-adjusted incidence of ATAD was 2.53/100 000/year, and no significant change in incidence was observed during the study period. The mean age was 66.9 ± 13.6 years and 66.0% (101/153) were Stanford type A. Of the whole group, 17.6% (27/153) died prior to hospital arrival, whereas the risk of death for patients who arrived alive to a hospital was 21.4% (27/126) within 24 h and 45.2% (57/126) at 30 days. During the course of the study, patients with type A dissection were more likely to undergo an operation and the management of type B dissection changed from open to endovascular repair. The 30-day mortality rate declined every year and the 5-year survival rate improved in the last third of the study. CONCLUSIONS: The incidence of ATAD was 2.53/100 000/year and remained constant throughout the study, contradicting recent perceptions of a rising incidence. ATAD, type A in particular, remains a highly lethal condition: Over half of all patients die within 30 days of the index event. A reduced 30-day mortality rate and an increased long-term survival rate indicate improved overall outcomes in patients with this complex condition.

[Outcomes of acute type A aortic dissection repairs in Iceland].

OBJECTIVES: Acute type A aortic dissection is a life-threatening disease associated with significant morbidity and mortality. Treatment is challenging and requires emergency surgery. This study presents for the first time the short- and long-term outcome of acute type A aortic dissection repairs in Iceland. MATERIALS AND METHODS: A retrospective review of 45 patients (mean age 60.7 ± 13.9 years, 68.9% male) treated for type A aortic dissection at Landspitali University Hospital between 1992 and 2014. Data was gathered from medical records about known risk factors, presenting symptoms, type of procedure, complications and operative mortality. RESULTS: Out of 45 operations the majority (73.3%) was performed in the second half of the study period. Nearly all patients presented with chest pain and 46.7% were in shock on arrival. Malperfusion syndrome was apparent in 26.7% of cases. A variety of operative methods were used, including hypothermic circulatory arrest in 31.1% of the cases and one-third of patients needed aortic root replacement. Reoperation rate for postoperative bleeding was 29.3% and perioperative stroke occurred in 14.6% of patients. The 30-day mortality rate was 22.2% (10 patients) and 5- and 10-year survival was 71.4 ± 8.2% and 65.4 ± 9.4%, respectively. CONCLUSIONS: The short-term outcomes of surgical repair for acute type A aortic dissection in Iceland is comparable to neighbouring countries, including 30-day mortality and long-term survival. Complications, however, are common, especially reoperations for bleeding. 1Department of Cardiothoracic Surgery, Landspitali University Hospital, 2Faculty of Medicine, University of Iceland. KEY WORDS: Aortic dissection type A, aortic aneurysm, open heart surgery, complications, operative mortality, survival. Correspondence: Arnar Geirsson, arnarge@landspitali.is.