Haemodynamic and clinical outcomes at 5 years according to predicted prosthesis-patient mismatch after transcatheter aortic valve replacement.

BACKGROUND/PURPOSE: Although the impact of predicted prosthesis-patient mismatch (PPMP) on outcomes after surgical aortic valve replacement is well established, studies on PPMP in transcatheter aortic valve replacement (TAVR) are limited. This study investigated the effects of PPMp on haemodynamic and 5-year clinical outcomes after TAVR. METHODS/MATERIALS: We analysed 1733 patients who underwent TAVR. PPMp was defined using two different methods: 1) normal reference values of the effective orifice area for each valve type and size indexed to body surface area (PPMp1; n = 1733) and 2) reference values for aortic annulus area or perimeter assessed with pre-procedural computed tomography indexed to body surface area (PPMp2; n = 1227). The primary endpoint was the composite of all-cause death and/or rehospitalisation for heart failure at 5 years. RESULTS: The incidence of PPMp1 was 11.7 % and 0.8 % in moderate and severe cases, respectively. PPMp2 was classified as either moderate (3.8 %) or severe (0 %). Rates of residual mean aortic gradient ≥20 mmHg significantly increased depending on PPMp1 severity (no PPMp1: 3.1 % vs. moderate PPMp1: 26.8 % vs. severe PPMp1: 53.9 %, p < 0.0001) and PPMp2 (no PPMp2: 4.1 % vs. moderate PPMp2: 12.8 %, p = 0.0049). Neither of PPMP methods were associated with the composite outcome in total cohort; however, PPMP1 was significantly related to worse clinical outcomes at 5 years among patients with reduced left ventricular ejection fraction (LVEF) in multivariate analysis (HR: 1.87; 95 % CI: 1.02-3.43). CONCLUSIONS: The impact of PPMP on TAVR clinical outcomes may not be negligible in patients with low LVEF.

Long-Term Assessment of Survival After Transcatheter Aortic Valve Implantation　- Insights From the International Transcatheter Aortic Valve Implantation Registry.

BACKGROUND: Transcatheter aortic valve implantation (TAVI) is an established treatment for severe aortic stenosis (AS), but despite estimates of life expectancy after TAVI being essential in heart team discussion, these data are scarce. Therefore, the current study sought to assess long-term survival and its trends in relation to chronological age, surgical risk, and treatment period.Methods and Results: We included 2,414 consecutive patients who underwent TAVI for severe symptomatic AS between 2008 and 2021 at 2 international centers. For the analysis, long-term survival was evaluated according to age, surgical risk, and treatment period categorized into 3 groups, respectively. The longest follow-up was 13.5 years. Overall survival was 67.6% at 5 years and 26.9% at 10 years. Younger patients, lower surgical risk, and later treatment period showed better survival (log-rank P<0.001, respectively). In the multivariate analysis, age <75years, lower surgical risk, and later time period were significantly associated with better survival. The incidence of paravalvular leakage ≥moderate, red blood cell transfusion, and acute kidney injury were independently associated with increasing risk of 5-year death. CONCLUSIONS: In a real-world registry, survival was substantial following TAVI, especially in younger and lower surgical-risk patients, with improving outcomes over time. This should be considered in heart team discussions of life-long management for AS patients after TAVI.

Risk Assessment of Permanent Pacemaker Implantation After Transcatheter Aortic Valve Implantation in Patients With Preexisting Right Bundle Branch Block.

Preexisting right bundle branch block (RBBB) is the strongest predictor for permanent pacemaker implantation (PPI) after transcatheter aortic valve implantation (TAVI). However, the risk assessment for new PPI and effective procedural strategy for preventing new PPI in patients with preexisting RBBB are still unclear. This study stratified the new PPI risk after TAVI and investigated the impact of implantation strategy in a preexisting RBBB cohort. We analyzed 237 patients with preexisting RBBB who underwent TAVI. The primary endpoint was the incidence of new PPI. Multivariate analyses investigating predictors for new PPI were performed. The overall PPI rate was 33.3%. Significant baseline predictors for new PPI were combination of RBBB, left anterior or posterior fascicular block, and first-degree atrioventricular block (odds ratio [OR] 2.55, 95% confidence interval [CI] 1.09 to 5.04), high calcium volume of noncoronary cusp (OR 2.08, 95% CI 1.05 to 4.10), and membranous septum (MS) length <2 mm (OR 2.02, 95% CI 1.09 to 3.75) in the univariate analysis and MS length <2 mm (OR 2.25, 95% CI 1.06 to 4.82) in the multivariate analysis. On the multivariate analysis including procedural variables, predilatation (OR 2.41, 95% CI 1.01 to 5.83), self-expanding valves (Corevalve, Evolut R, and Evolut Pro/Pro+; Medtronic Inc., Minneapolis, Minnesota) or mechanical expanding valves (Lotus/Lotus Edge; Boston Scientifics, Marlborough, Massachusetts) (OR 3.00, 95% CI 1.31 to 6.91), and implantation depth > MS length (OR 4.27, 95% CI 1.81 to 10.08) were significantly associated with new PPI. The incidence of new PPI increased according to the number of baseline predictors (0: 20.9%, 1: 34.3%, and ≥2: 52.0%) and procedural predictors (0: 3.7%, 1: 20.9%, 2: 40.5%, and 3: 60.0%). New PPI risk in a preexisting RBBB subset could be stratified by baseline factors. Device selection and implantation strategy considering MS length could prevent new PPI even in these high-risk population.

Hemodynamics and Conduction Disturbance After Transcatheter Aortic Valve Implantation With SAPIEN3 Ultra Versus SAPIEN3: The HomoSAPIEN 2 Study.

The optimal percent oversizing (%OS) using the SAPIEN3 Ultra (S3U) weighing the incidence of paravalvular regurgitation (PVR) ≥ mild against the risk of conduction disturbance (CD) is not known. This study sought to define an optimal extent of the annulus area %OS suitable for transcatheter aortic valve implantation with the S3U compared with the SAPIEN3 (S3). A total of 350 patients with the S3U were compared with 606 patients with the S3. Patients were categorized depending on the degree of %OS. PVR ≥ mild was observed in 8.9% of patients with the S3U and in 21.8% of those with the S3 (p <0.001). The S3U demonstrated a sustainably lower incidence of PVR ≥ mild than the S3 in any extent of %OS. There was an inverse proportional relation between the extent of %OS and frequency of PVR ≥ mild in the S3, whereas the S3U group provided little change. The incidences of PVR ≥ mild were steady >5%OS in the S3 (5% to 10%OS: 13.3%, and >10%OS: 12.1%) and >0%OS in the S3U (0% to 5%OS: 5.9%, 5% to 10%OS: 6.0%, and >10%OS: 6.1%). An increasing %OS was independently associated with the occurrence of CD (<0%OS: 9.8%, 0% to 5%OS: 13.1%, 5% to 10%OS: 16.6%, and >10%OS: 19.2%, p = 0.012). The incidence of PVR ≥ mild and/or CD was the lowest (10.1%) in the 0% to 5%OS in patients with the S3U. In conclusion, the HomoSAPIEN2 study suggests that the S3U tolerates a lesser degree of %OS for mitigating PVR ≥ mild than the S3. Minimal %OS, ranging from 0% to 5%, may be optimal for the S3U with balancing the risk of PVR and CD. Trial Identifier: UMIN000040413/URL: https://center6.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000046115.

Conduction Disturbance After Transcatheter Aortic Valve Implantation With Self- or Balloon-Expandable Valve According to the Implantation Depth.

Membranous septum (MS) length, in conjunction with implantation depth (ID), is known as a determinant of conduction disturbance (CD) after transcatheter aortic valve implantation (TAVI). However, its impact might be dissimilar among valve types because each valve has a different platform. This study sought to investigate the different impacts of ID and MS length on the new-onset CD between ACURATE neo and SAPIEN 3. This study included patients without a previous permanent pacemaker implantation who underwent TAVI with ACURATE neo and SAPIEN 3 and divided them into 2 groups based on the ID according to MS length (deep and shallow implantation group). Deep implantation was defined as transcatheter heart valve implantation deeper than MS length. The primary endpoint was new-onset CD (new permanent pacemaker implantation or new-onset complete left bundle branch block). A total of 688 patients (deep implantation: n = 373, shallow implantation: n = 315) were identified as a study cohort. New-onset CD developed more frequently in the deep implantation group (16.6% vs 7.0%; p = 0.0001). Deep implantation was revealed as a predictor of new-onset CD. Moreover, deep implantation was significantly associated with new-onset CD after SAPIEN 3 implantation but not after ACURATE neo. Among patients with MS shorter than 2 mm, ACURATE neo was superior in terms of avoiding new-onset CD. In conclusion, the deep implantation was associated with new-onset CD after TAVI with SAPIEN 3 but not with ACURATE neo. These results may impact device selection in patients with a preexisting high risk of CD.

Impact of Mild Paravalvular Regurgitation on Long-Term Clinical Outcomes After Transcatheter Aortic Valve Implantation.

The impact of mild paravalvular regurgitation (PVR) after transcatheter aortic valve implantation (TAVI) remains controversial. We evaluated the impact of mild PVR after TAVI on long-term clinical outcomes. We included patients who underwent TAVI for severe symptomatic aortic stenosis between December 2008 and June 2019 at 2 international centers and compared all-cause death between the group with mild PVR (group 1) and the group with none or trace PVR (group 2). PVR was categorized using a 3-class grading scheme, and patients with PVR ≧ moderate and those who were lost to follow-up were excluded. This retrospective analysis included 1,404 patients (mean age 81.7 ± 6.5 years, 58.0% women). Three hundred fifty eight patients (25.5%) were classified into group 1 and 1,046 patients (74.5%) into group 2. At baseline, group 1 was older and had a lower body mass index, worse co-morbidities, and more severe aortic stenosis. To account for these differences, propensity score matching was performed, resulting in 332 matched pairs. Within these matched groups, during a mean follow-up of 3.2 years, group 1 had a significantly lower survival rate at 5 years (group 1: 62.0% vs group 2: 68.0%, log-rank p = 0.029, hazard ratio: 1.41 [95% confidence interval: 1.04 to 1.91]). In the matched cohort, patients with mild PVR had a significant 1.4-fold increased risk of mortality at 5 years after TAVI compared with those with none or trace PVR. Further studies with more patients are needed to evaluate the impact of longer-term outcomes.

Ultrasound-Guided Versus Conventional MANTA Vascular Closure Device Deployment After Transcatheter Aortic Valve Implantation.

Despite the development of device technology and operators' experience, access site vascular complications (VCs) remain one of the major concerns after transcatheter aortic valve implantation (TAVI). MANTA (Teleflex, Wayne, Pennsylvania) is a large-bore vascular closure device (VCD) with promising incidence of VC. Previously, we demonstrated that the ultrasound-guided MANTA (US-MANTA) technique further improved the outcomes compared with conventional MANTA (C-MANTA) without ultrasound guidance. The present study was established to prove the effectiveness of the technique in a larger population. In this study, we included 1,150 patients (335 patients with C-MANTA and 815 with US-MANTA) who received MANTA after TAVI from April 2017 to September 2021. The primary endpoint was MANTA-related VC. Overall VC, VCD failure, and bleeding complications were also assessed based on the Valve Academic Research Consortium 3 criteria. MANTA-related VC occurred in 12.5% in the C-MANTA group and 6.8% in the US-MANTA group (p = 0.001). VCD failure rate were 7.5% and 3.9%, respectively (p = 0.012). Valve Academic Research Consortium 3 major and minor VC were more frequent in C-MANTA group (major: 7.8% vs 4.4%, p = 0.023; minor: 8.1% vs 4.4%, p = 0.022). Multivariate analysis revealed US-MANTA as the negative predictor of MANTA-related VC (odds ratio 0.57, 95% confidence interval 0.36 to 0.89, p = 0.013). However, subgroup analysis showed the efficacy of the US-MANTA technique was limited to the patients without severely calcified puncture site (Pinteraction = 0.048). In conclusion, the US-MANTA technique was an effective strategy to reduce VC after transfemoral TAVI compared with C-MANTA.

Effect of 4% Albumin Solution vs Ringer Acetate on Major Adverse Events in Patients Undergoing Cardiac Surgery With Cardiopulmonary Bypass: A Randomized Clinical Trial.

Importance: In cardiac surgery, albumin solution may maintain hemodynamics better than crystalloids and reduce the decrease in platelet count and excessive fluid balance, but randomized trials are needed to compare the effectiveness of these approaches in reducing surgical complications. Objective: To assess whether 4% albumin solution compared with Ringer acetate as cardiopulmonary bypass prime and perioperative intravenous volume replacement solution reduces the incidence of major perioperative and postoperative complications in patients undergoing cardiac surgery. Design, Setting, and Participants: A randomized, double-blind, single-center clinical trial in a tertiary university hospital during 2017-2020 with 90-day follow-up postoperatively involving patients undergoing on-pump coronary artery bypass grafting; aortic, mitral, or tricuspid valve surgery; ascending aorta surgery without hypothermic circulatory arrest; and/or the maze procedure were randomly assigned to 2 study groups (last follow-up was April 13, 2020). Interventions: The patients received in a 1:1 ratio either 4% albumin solution (n = 693) or Ringer acetate solution (n = 693) as cardiopulmonary bypass priming and intravenous volume replacement intraoperatively and up to 24 hours postoperatively. Main Outcomes and Measures: The primary outcome was the number of patients with at least 1 major adverse event: death, myocardial injury, acute heart failure, resternotomy, stroke, arrhythmia, bleeding, infection, or acute kidney injury. Results: Among 1407 patients randomized, 1386 (99%; mean age, 65.4 [SD, 9.9] years; 1091 men [79%]; 295 women [21%]) completed the trial. Patients received a median of 2150 mL (IQR, 1598-2700 mL) of study fluid in the albumin group and 3298 mL (IQR, 2669-3500 mL) in the Ringer group. The number of patients with at least 1 major adverse event was 257 of 693 patients (37.1%) in the albumin group and 234 of 693 patients (33.8%) in the Ringer group (relative risk albumin/Ringer, 1.10; 95% CI, 0.95-1.27; P = .20), an absolute difference of 3.3 percentage points (95% CI, -1.7 to 8.4). The most common serious adverse events were pulmonary embolus (11 [1.6%] in the albumin group vs 8 [1.2%] in the Ringer group), postpericardiotomy syndrome (9 [1.3%] in both groups), and pleural effusion with intensive care unit or hospital readmission (7 [1.0%] in the albumin group vs 9 [1.3%] in the Ringer group). Conclusions and Relevance: Among patients undergoing cardiac surgery with cardiopulmonary bypass, treatment with 4% albumin solution for priming and perioperative intravenous volume replacement solution compared with Ringer acetate did not significantly reduce the risk of major adverse events over the following 90 days. These findings do not support the use of 4% albumin solution in this setting. Trial Registration: ClinicalTrials.gov Identifier: NCT02560519.

Device Failure in Bicuspid Aortic Stenosis Following Transcatheter Aortic Valve Implantation.

Recent studies showed the favorable outcomes of transcatheter aortic valve implantation (TAVI) in patients with bicuspid aortic valve (BAV) stenosis. However, data on the relation between BAV morphology and optimal transcatheter heart valve (THV) selection are limited. This study sought to evaluate the determinants of device performance in patients with BAV who underwent TAVI. Consecutive patients with BAV who underwent TAVI with the SAPIEN 3 from multicenters were evaluated. Outcomes were the incidence and predictors of device failure. Device failure was defined as peak aortic velocity >3.0 m/s, mean pressure gradient >20 mm Hg, moderate or severe paravalvular leakage and/or procedure mortality. A total of 187 patients with BAV were identified, aged 77 years, and 38.0% were women. A total of 37 patients (19.8%) were treated with 23-mm valve, 58 (31.0%) with 26-mm valve, and 92 (49.2%) with 29-mm valve. Predischarge echocardiogram demonstrated 37 patients (19.8%) with device failure. BAV with excessive leaflet calcification plus calcified raphe (EC-BAV) (OR 16.7, 95% CI 1.99 to 39.6) and smaller THV (OR 4.41, 95% CI 1.43 to 13.6) were independently associated with increased risk of device failure. In addition, 4.0%, 5.1%, and 11.1% of device failures were observed in patients without EC-BAV who underwent TAVI with 23-, 26- and 29-mm THV (p = 0.47), respectively, and 91.7%, 31.6% and 23.2% in those with EC-BAV, respectively (p <0.001). In conclusion, EC-BAV morphology was the major determinant of a device failure after TAVI. Moreover, TAVI in patients with EC-BAV requiring small SAPIEN 3 could be challenging. Further data on device and treatment selection in patients with BAV are still warranted.

Epitranscriptomics of Ischemic Heart Disease-The IHD-EPITRAN Study Design and Objectives.

Epitranscriptomic modifications in RNA can dramatically alter the way our genetic code is deciphered. Cells utilize these modifications not only to maintain physiological processes, but also to respond to extracellular cues and various stressors. Most often, adenosine residues in RNA are targeted, and result in modifications including methylation and deamination. Such modified residues as N-6-methyl-adenosine (m6A) and inosine, respectively, have been associated with cardiovascular diseases, and contribute to disease pathologies. The Ischemic Heart Disease Epitranscriptomics and Biomarkers (IHD-EPITRAN) study aims to provide a more comprehensive understanding to their nature and role in cardiovascular pathology. The study hypothesis is that pathological features of IHD are mirrored in the blood epitranscriptome. The IHD-EPITRAN study focuses on m6A and A-to-I modifications of RNA. Patients are recruited from four cohorts: (I) patients with IHD and myocardial infarction undergoing urgent revascularization; (II) patients with stable IHD undergoing coronary artery bypass grafting; (III) controls without coronary obstructions undergoing valve replacement due to aortic stenosis and (IV) controls with healthy coronaries verified by computed tomography. The abundance and distribution of m6A and A-to-I modifications in blood RNA are charted by quantitative and qualitative methods. Selected other modified nucleosides as well as IHD candidate protein and metabolic biomarkers are measured for reference. The results of the IHD-EPITRAN study can be expected to enable identification of epitranscriptomic IHD biomarker candidates and potential drug targets.

Assessment of myocardial viability with [15O]water PET: A validation study in experimental myocardial infarction.

BACKGROUND: Assessment of myocardial viability is often needed in patients with chest pain and reduced ejection fraction. We evaluated the performance of reduced resting MBF, perfusable tissue fraction (PTF), and perfusable tissue index (PTI) in the assessment of myocardial viability in a pig model of myocardial infarction (MI). METHODS AND RESULTS: Pigs underwent resting [15O]water PET perfusion study 12 weeks after surgical (n = 16) or 2 weeks after catheter-based (n = 4) occlusion of the proximal left anterior descending coronary artery. MBF, PTF, and PTI were compared with volume fraction of MI in matched segments as assessed by triphenyl tetrazolium chloride staining of LV slices. MBF and PTF were lower in infarcted than non-infarcted segments. Segmental analysis of MBF showed similar area under the curve (AUC) of 0.85, 0.86, and 0.90 with relative MBF, PTF, and PTI for the detection of viable myocardium defined as infarct volume fraction of < 75%. Cut-off values of relative MBF of ≥ 67% and PTF of ≥ 66% resulted in accuracies of 90% and 81%, respectively. CONCLUSIONS: Our results indicate that resting MBF, PTF, and PTI based on [15O]water PET perfusion imaging are useful for the assessment of myocardial viability.

Effect and safety of 4% albumin in the treatment of cardiac surgery patients: study protocol for the randomized, double-blind, clinical ALBICS (ALBumin In Cardiac Surgery) trial.

BACKGROUND: In cardiac surgery with cardiopulmonary bypass (CPB), large amounts of fluids are administered. CPB priming with crystalloid solution causes marked hemodilution and fluid extravasation. Colloid solutions may reduce fluid overload because they have a better volume expansion effect than crystalloids. The European Medicines Agency does not recommend the use of hydroxyethyl starch solutions (HES) due to harmful renal effects. Albumin solution does not impair blood coagulation but the findings on kidney function are conflicting. On the other hand, albumin may reduce endothelial glycocalyx destruction and decrease platelet count during CPB. No large randomized, double-blind, clinical trials have compared albumin solution to crystalloid solution in cardiac surgery. METHODS/DESIGN: In this single-center, double-blind, randomized controlled trial comprising 1386 adult cardiac surgery patients, 4% albumin solution will be compared to Ringer's acetate solution in CPB priming and volume replacement up to 3200 mL during surgery and the first 24 h of intensive care unit stay. The primary efficacy outcome is the number of patients with at least one major adverse event (MAE) during 90 postoperative days (all-cause death, acute myocardial injury, acute heart failure or low output syndrome, resternotomy, stroke, major arrhythmia, major bleeding, infection compromising post-procedural rehabilitation, acute kidney injury). Secondary outcomes are total number of MAEs, incidence of major adverse cardiac events (MACE; cardiac death, acute myocardial injury, acute heart failure, arrhythmia), amount of each type of blood product transfused (red blood cells, fresh frozen plasma, platelets), total fluid balance at the end of the intervention period, total measured blood loss, development of acute kidney injury, days alive without mechanical ventilation in 90 days, days alive outside intensive care unit at 90 days, days alive at home at 90 days, and 90-day mortality. DISCUSSION: The findings of this study will provide new evidence regarding efficacy and safety of albumin solution in adult patients undergoing cardiac surgery with CPB. TRIAL REGISTRATION: EudraCT (clinicaltrialsregister.eu) 2015-002556-27 Registered 11 Nov 2016 and ClinicalTrials.gov NCT02560519. Registered 25 Sept 2015.

Ultrasound-Navigated Manta Deployment After Removal of Extracorporeal Membrane Oxygenation Cannula.

The case provided suggests that an ultrasound-navigated Manta device works well in closing percutaneously the peripheral arterial extracorporeal membrane oxygenation cannulation site. Ultrasonography use during extracorporeal membrane oxygenation decannulation can further diminish the possible device-related technical failures (toggle or collagen protrusion through the vessel wall, toggle stacking into calcifications, or delivery failure of the collagen pad) leading to bleeding and vascular complications. Further studies are needed on this topic.

Determinants of Myocardial Strain in Experimental Chronic Myocardial Infarction.

We evaluated the relationships between regional myocardial strain measured by speckle tracking echocardiography and viability, fibrosis, hypertrophy and oxygen consumption in the infarcted or remote myocardium in a pig model of chronic myocardial infarction (MI). Thirteen farm pigs with surgical occlusion of the left anterior descending coronary artery and five sham-operated pigs were studied 3 mo post-MI. Computed tomography revealed significant left ventricle remodeling. Reduced radial or circumferential strain identified areas of transmural infarction (area under the curve: 0.82 and 0.79, respectively). In the remote non-infarcted area, radial strain correlated inversely with the amount of fibrosis (r = -0.66, p = 0.04) and myocyte hypertrophy (r = -0.68, p = 0.03). Radial strain rate inversely correlated with myocardial resting oxygen consumption assessed with 11C-labeled acetate positron emission tomography (r = -0.71, p = 0.006). In conclusion, myocardial strain and strain rate reflect fibrosis, hypertrophy and oxygen consumption of the remote areas after MI.

Accuracy of echocardiographic area-length method in chronic myocardial infarction: comparison with cardiac CT in pigs.

BACKGROUND: We evaluated echocardiographic area-length methods to measure left ventricle (LV) volumes and ejection fraction (EF) in parasternal short axis views in comparison with cardiac computed tomography (CT) in pigs with chronic myocardial infarction (MI). METHODS: Male farm pigs with surgical occlusion of the left anterior descending coronary artery (n = 9) or sham operation (n = 5) had transthoracic echocardiography and cardiac-CT 3 months after surgery. We measured length of the LV in parasternal long axis view, and both systolic and diastolic LV areas in parasternal short axis views at the level of mitral valve, papillary muscles and apex. Volumes and EF of the LV were calculated using Simpson's method of discs (tri-plane area) or Cylinder-hemiellipsoid method (single plane area). RESULTS: The pigs with coronary occlusion had anterior MI scars and reduced EF (average EF 42 ± 10%) by CT. Measurements of LV volumes and EF were reproducible by echocardiography. Compared with CT, end-diastolic volume (EDV) measured by echocardiography showed good correlation and agreement using either Simpson's method (r = 0.90; mean difference -2, 95% CI -47 to 43 mL) or Cylinder-hemiellipsoid method (r = 0.94; mean difference 3, 95% CI -44 to 49 mL). Furthermore, End-systolic volume (ESV) measured by echocardiography showed also good correlation and agreement using either Simpson's method (r = 0.94; mean difference 12 ml, 95% CI: -16 to 40) or Cylinder-hemiellipsoid method (r = 0.97; mean difference:13 ml, 95% CI: -8 to 33). EF was underestimated using either Simpson's method (r = 0.78; mean difference -6, 95% CI -11 to 1%) or Cylinder-hemiellipsoid method (r = 0.74; mean difference -4, 95% CI-10 to 2%). CONCLUSION: Our results indicate that measurement of LV volumes may be accurate, but EF is underestimated using either three or single parasternal short axis planes by echocardiography in a large animal model of chronic MI.

Systemic Dosing of Thymosin Beta 4 before and after Ischemia Does Not Attenuate Global Myocardial Ischemia-Reperfusion Injury in Pigs.

The use of cardiopulmonary bypass (CPB) and aortic cross-clamping causes myocardial ischemia-reperfusion injury (I-RI) and can lead to reduced postoperative cardiac function. We investigated whether this injury could be attenuated by thymosin beta 4 (TB4), a peptide which has showed cardioprotective effects. Pigs received either TB4 or vehicle and underwent CPB and aortic cross-clamping for 60 min with cold intermittent blood-cardioplegia and were then followed for 30 h. Myocardial function and blood flow was studied by cardiac magnetic resonance and PET imaging. Tissue and plasma samples were analyzed to determine the amount of cardiomyocyte necrosis and apoptosis as well as pharmacokinetics of the peptide. In vitro studies were performed to assess its influence on blood coagulation and vasomotor tone. Serum levels of the peptide were increased after administration compared to control samples. TB4 did not decrease the amount of cell death. Cardiac function and global myocardial blood flow was similar between the study groups. At high doses a vasoconstrictor effect on mesentery arteries and a vasodilator effect on coronary arteries was observed and blood clot firmness was reduced when tested in the presence of an antiplatelet agent. Despite promising results in previous trials the cardioprotective effect of TB4 was not demonstrated in this model for global myocardial I-RI.

Effect of levosimendan therapy on myocardial infarct size and left ventricular function after acute coronary occlusion.

BACKGROUND: Levosimendan is an inotropic agent with cardioprotective and vasodilating properties used for the management of acutely decompensated heart failure. We studied the effects of levosimendan treatment on the size of myocardial infarction (MI) and left ventricular (LV) function in experimental pig model of post MI heart failure. METHODS: After occlusion of the left anterior descending (LAD) coronary artery, animals received levosimendan 5 mg/kg/day orally for 8 weeks (n=7) or no treatment (n=18). One week after stopping treatment, transthoracic echocardiography, CT scan and positron emission tomography were performed to evaluate myocardial function, perfusion and oxidative metabolism. Histology was used to confirm the size of MI and features of LV remodelling. RESULTS: The size of MI was significantly smaller in the levosimendan group than in the controls (12±13% vs 27±15% of the LV, p=0.03). End-diastolic volume (EDV) and end-systolic volume (ESV) were smaller in the levosimendan than in the control group (EDV 161±29 mL vs 245±84 mL, p=0.06; ESV 81±18 mL vs 149±67 mL, p=0.03), whereas ejection fraction tended to be higher in the levosimendan group (50±6% vs 41±8%, p=0.06). CONCLUSIONS: Eight weeks of levosimendan therapy after recent LAD occlusion decreases the size of MI and leads to better preservation of LV function as well as reduced LV remodelling.

[18F]FDG Accumulation in Early Coronary Atherosclerotic Lesions in Pigs.

OBJECTIVE: Inflammation is an important contributor to atherosclerosis progression. A glucose analogue 18F-fluorodeoxyglucose ([18F]FDG) has been used to detect atherosclerotic inflammation. However, it is not known to what extent [18F]FDG is taken up in different stages of atherosclerosis. We aimed to study the uptake of [18F]FDG to various stages of coronary plaques in a pig model. METHODS: First, diabetes was caused by streptozotocin injections (50 mg/kg for 3 days) in farm pigs (n = 10). After 6 months on high-fat diet, pigs underwent dual-gated cardiac PET/CT to measure [18F]FDG uptake in coronary arteries. Coronary segments (n = 33) were harvested for ex vivo measurement of radioactivity and autoradiography (ARG). RESULTS: Intimal thickening was observed in 16 segments and atheroma type plaques in 10 segments. Compared with the normal vessel wall, ARG showed 1.7±0.7 times higher [18F]FDG accumulation in the intimal thickening and 4.1±2.3 times higher in the atheromas (P = 0.004 and P = 0.003, respectively). Ex vivo mean vessel-to-blood ratio was higher in segments with atheroma than those without atherosclerosis (2.6±1.2 vs. 1.3±0.7, P = 0.04). In vivo PET imaging showed the highest target-to-background ratio (TBR) of 2.7. However, maximum TBR was not significantly different in segments without atherosclerosis (1.1±0.5) and either intimal thickening (1.2±0.4, P = 1.0) or atheroma (1.6±0.6, P = 0.4). CONCLUSIONS: We found increased uptake of [18F]FDG in coronary atherosclerotic lesions in a pig model. However, uptake in these early stage lesions was not detectable with in vivo PET imaging. Further studies are needed to clarify whether visible [18F]FDG uptake in coronary arteries represents more advanced, highly inflamed plaques.

Cardiac remodeling in a new pig model of chronic heart failure: Assessment of left ventricular functional, metabolic, and structural changes using PET, CT, and echocardiography.

AIMS: Large animal models are needed to study disease mechanisms in heart failure (HF). In the present study we characterized the functional, metabolic, and structural changes of myocardium in a novel pig model of chronic myocardial infarction (MI) by using multimodality imaging and histology. METHODS AND RESULTS: Male farm pigs underwent a two-step occlusion of the left anterior descending coronary artery with concurrent distal ligation and implantation of a proximal ameroid constrictor (HF group), or sham operation (control group). Three months after the operation, cardiac output and wall stress were measured by echocardiography. Left ventricle (LV) volumes and mass were measured by computed tomography (CT). Myocardial perfusion was evaluated by [(15)O]water and oxygen consumption using [(11)C]acetate positron emission tomography, and the efficiency of myocardial work was calculated. Histological examinations were conducted to detect MI, hypertrophy, and fibrosis. Animals in the HF group had a large anterior MI scar. CT showed larger LV diastolic volume and lower ejection fraction in HF pigs than in controls. Perfusion and oxygen consumption in the remote non-infarcted myocardium were preserved in HF pigs as compared to controls. Global LV work and efficiency were significantly lower in HF than control pigs and was associated with increased wall stress. Histology showed myocyte hypertrophy but not increased interstitial fibrosis in the remote segments in HF pigs. CONCLUSIONS: The chronic post-infarction model of HF is suitable for studies aimed to evaluate LV remodeling and changes in oxidative metabolism and can be useful for testing new therapies for HF.