Pig kidney xenotransplantation: Progress toward clinical trials

Pig organ xenotransplantation offers a solution to the shortage of deceased human organs for transplantation. The pathobiological response to a pig xenograft is complex, involving antibody, complement, coagulation, inflammatory, and cellular responses. To overcome these barriers, genetic manipulation of the organ-source pigs has largely been directed to two major aims-(a) deletion of expression of the known carbohydrate xenoantigens against which humans have natural (preformed) antibodies, and (b) transgenic expression of human protective proteins, for example, complement- and coagulation-regulatory proteins. Conventional (FDA-approved) immunosuppressive therapy is unsuccessful in preventing an adaptive immune response to pig cells, but blockade of the CD40:CD154 costimulation pathway is successful. Survival of genetically engineered pig kidneys in immunosuppressed nonhuman primates can now be measured in months. Non-immunological aspects, for example, pig renal function, a hypovolemia syndrome, and rapid growth of the pig kidney after transplantation, are briefly discussed. We suggest that patients on the wait-list for a deceased human kidney graft who are unlikely to receive one due to long waiting times are those for whom kidney xenotransplantation might first be considered. The potential risk of infection, public attitudes to xenotransplantation, and ethical, regulatory, and financial aspects are briefly addressed.

Ten-year all-cause death after percutaneous or surgical revascularization for men and women with multivessel or left main coronary artery disease: insights from the SYNTAX extended survival study

Background

In patients with complex coronary artery disease (CAD), women favored coronary artery bypass grafting surgery (CABG) compared to percutaneous coronary intervention (PCI) at 5 years in the SYNTAX trial, whereas mortality rates after PCI and CABG were not different in men. On the other hand, poor outcomes of women undergoing PCI were not observed in the PRECOMBAT and BEST trials.

The long-term optimal revascularization strategy according to gender has not been fully evaluated.

Purpose

In the SYNTAX Extended Survival (SYNTAXES) study, no significant difference existed in all-cause death between PCI and CABG at 10 years. This study aimed to assess treatment effect of PCI and CABG for 10-year all-cause death according to gender.

Methods

The SYNTAXES study evaluated vital status up to 10 years in 1,800 patients with de novo three-vessel disease (3VD) and/or left main coronary artery disease (LMCAD) randomized to treatment with CABG or PCI in the SYNTAX trial, and the pre-specified primary endpoint was all-cause death at 10 years. In this prespecified analysis, all-cause death at 10 years according to gender in patients undergoing PCI or CABG was evaluated.

Results

Of 1800 patients, 402 (22.3%) were women and 1398 (77.7%) were men. In women, the rate of mortality was significantly higher in the PCI arm at 5 years than in the CABG arm (19.3% vs. 10.3%; Log-rank p=0.010, Figure A), but the rates of mortality were not different at 10 years between the PCI and CABG arms (33.0% vs. 32.5%; Log-rank p=0.600, Figure A). In men, the mortality rate tended to be higher in the PCI arm at 10 years than in the CABG arm (27.0% vs. 22.5%; Log-rank p=0.082, Figure B), although the mortality rates were not different at 5 years between the PCI and CABG arms (12.4% vs. 12.3%; Log-rank p=0.957, Figure B).

Conclusion

The efficacy of CABG observed at 5 years disappeared at 10 years in women, whereas the efficacy of CABG became apparent after 5 years in men.

Figure 1

Funding Acknowledgement

Type of funding source: Public Institution(s). Main funding source(s): Erasmus University Medical Centre, Rotterdam, Netherlands, reference: MEC-2016-716

Impact of pulmonary wave reflection in heart failure: right ventricular-arterial coupling

Background

Pulmonary wave reflection, an important loading component on RV, would help better describe right ventricular (RV) – arterial uncouplingin type II pulmonary hypertension (PH).

Methods

This study included 105patients with type II PH (age = 72±13 years old, ejection fraction = 47±21%). Pulmonary wave reflection was characterised by estimating pressure and velocity profiles from Doppler measurement and separating pressure waveform into forward (Pf) and backward pressure (Pb) waves based on the concept of wave intensity. The relationship of RV strain against Pb or pulmonary artery systolic pressure (PASP) was compared between patients with and without subsequent event of worsening heart failure, using discriminant analysis.

Results

Sample profiles of pressure waveforms illustrated Pb accounted for a significant proportion of total pressure (figure A). When RV strain was plotted against Pb, the distribution of both group were clearly separated, indicating significant uncoupling in patients with events, whereas when plotted against PASP, the both groups were overlapped (figure B and C).

Conclusions

Pulmonary wave reflection can better describe RV-arterial uncoupling in type II PH.

Funding Acknowledgement

Type of funding source: None

The immune system in infants: Relevance to xenotransplantation

Despite the improvement in surgical interventions in the treatment of congenital heart disease, many life-threatening lesions (eg, hypoplastic left heart syndrome) ultimately require transplantation. However, there is a great limitation in the availability of deceased human cardiac donors of a suitable size. Hearts from genetically engineered pigs may provide an alternative source. The relatively immature immune system in infants (eg, absence of anti-carbohydrate antibodies, reduced complement activation, reduced innate immune cell activity) should minimize the risk of early antibody-mediated rejection of a pig graft. Additionally, recipient thymectomy, performed almost routinely as a preliminary to orthotopic heart transplantation in this age-group, impairs the T-cell response. Because of the increasing availability of genetically engineered pigs (eg, triple-knockout pigs that do not express any of the three known carbohydrate antigens against which humans have natural antibodies) and the ability to diagnose congenital heart disease during fetal life, cardiac xenotransplantation could be preplanned to be carried out soon after birth. Because of these several advantages, prolonged graft survival and even the induction of tolerance, for example, following donor-specific pig thymus transplantation, are more likely to be achieved in infants than in adults. In this review, we summarize the factors in the infant immune system that would be advantageous in the success of cardiac xenotransplantation in this age-group.

Impact of periprocedural myocardial infarction on 10-year mortality after percutaneous coronary intervention or coronary artery bypass grafting for multivessel or left main coronary artery disease

Background

Periprocedural myocardial infarction (PMI) occurs frequently after both percutaneous coronary intervention (PCI) and bypass grafting surgery (CABG) in patients with complex coronary artery disease (CAD), and PMI has been shown to have a detrimental impact on mortality. On the other hand, long-term impact of PMI on mortality has not been fully evaluated.

Purpose

This study aimed to assess the impact of PMI according to SCAI definition on 10-year all-cause death in patients with complex CAD.

Methods

The SYNTAX Extended Survival (SYNTAXES) study evaluated vital status up to 10 years in 1800 patients with de novo three-vessel disease and/or left main coronary artery disease randomized to treatment with CABG or PCI in the SYNTAX trial. Blood was sampled for creatine kinase (CK) pre- and post-revascularisation, and the cardiac specific MB iso-enzyme (CK-MB) was determined only if the CK ratio ≥2 x the upper limit of normal (ULN). If the CK ratio <2 ULN, CK-MB assessment was not mandated. In this analysis, patients with at least one blood sampling within 48 hours of the procedure were included. PMI was defined as follows; peak CK-MB measured within 48 hours of the procedure ≥10 x ULN, or ≥5 x ULN with new Q-waves in 2 contiguous leads or new persistent left bundle branch block.

Results

Of 1800 patients, 1679 (93.2%) patients were included. Of 877 patients treated with PCI, PMI occurred in 26 patients (3.0%), whereas 14 (1.7%) PMIs were observed in 802 patients treated with CABG. Compared with patients without PMI, patients with PMI presented with unstable angina more frequently (45.0% vs. 28.7, p=0.033), and had a higher rate of bifurcation lesion (87.5% vs. 72.5, p=0.046). PMI was associated with a higher all-cause mortality at 10 years compared with no PMI (55.3% vs. 25.4%; Log-rank p<0.001, Figure), which was mainly driven by a high mortality rate within 1 year. In patients undergoing PCI, the mortality rates were significantly higher in patients with PMI not only within 1 year (Log-rank p<0.001) but also beyond one year (Log-rank p=0.016), compare to patients without PMI (Figure). On the other hand, in patients undergoing CABG, a higher mortality rate in patients with PMI was observed until 1 year (Log-rank p<0.001), but the impact of PMI on mortality beyond one year after CABG subsided (Log-rank p=0.308) (Figure 1).

Conclusion

PMI was associated with a poor prognosis at 10 years. The impact of PMI on mortality was strong within one year. Of note, the impact of PMI on mortality persisted beyond 1 year only in patients undergoing PCI. Patients who were treated with PCI and suffered PMI need careful follow-up beyond one year after revascularization.

Figure 1

Funding Acknowledgement

Type of funding source: None

Evaluation of temporal changes in longitudinal strain distribution during the systolic period to determine left ventricular activation sequence: a study using 2D speckle-tracking echocardiography

Background

Evaluation of two-dimensional (2D) speckle-tracking longitudinal strain (LS) is useful for assessing global and regional left ventricular (LV) dysfunction.

Purpose

The purpose of this study was to test the hypothesis that temporal changes in regional 2D-LS distribution, (i.e., changes in area and intensity of the negative strain), during the systolic period may reflect the LV activation sequence.

Methods

We studied 52 patients with an ejection fraction <35% who were classified into four groups: complete left bundle branch block (LBBB, QRS 162±17 ms, n=17); right ventricular pacing from inferior septum (RVP, QRS 180±29 ms, n=16); left VP from lateral branch of the coronary sinus (LVP, QRS 182±21 ms, n=9); and no conduction block (Narrow QRS, QRS 100±9 ms, n=19). Longitudinal strain was evaluated in three standard apical views, and then bulls-eye distribution maps were constructed every 50 ms from the QRS onset to aortic valve closing (AVC) and at the time of the end of QRS. Segments indicating negative strain at the end of QRS were regarded as an early contraction site. Segments with intensifying negativity of strain as it got closer to the AVC were regarded as a late contraction site.

Results

In patients with LBBB, negative strain appeared initially in the septum region. Then, the contracted area enlarged including the apical region, and the basal lateral region contracted late. On the other hand, Narrow QRS showed a few regional differences in strain at the end of QRS (standard deviation in 17-segments: Narrow QRS 1.3±0.4%*, LBBB 3.3±1.1%, RVP 3.2±1.0%, LVP 3.3±1.1%, *p<0.001), and contracted homogeneously during the systolic period. RVP and LVP showed negative strain at the end of QRS in septum and lateral regions respectively, with the contracted area becoming enlarged towards the opposite regions of the early contracted regions.

Conclusion

The 2D-LS distribution during the systolic period reflects the LV contraction process in patients with an altered ventricular activation sequence, and may have potential for identifying the regions of early activation site and subsequent activation propagation.

Funding Acknowledgement

Type of funding source: None

Ten-year all-cause death in elderly patients undergoing percutaneous coronary intervention or coronary artery bypass grafting: a prespecified subgroup analysis of the SYNTAX Extended Survival study

Background

Coronary artery disease is the leading cause of death among elderly men and women worldwide. The aging society worldwide will lead to increasing numbers of elderly patients with multivessel coronary artery disease. Although age is recognized as one of the most important factors in a decision-making for revascularization of multivessel coronary artery disease, the very long-term outcomes in patients undergoing revascularization by percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG) is still unclear.

Objectives

The aim of the present study was to investigate the association between revascularization strategies and 10-year outcomes in elderly patients.

Methods

The SYNTAX Extended Survival (SYNTAXES) study (NCT 03417050) is an investigator-driven extension of follow-up of a multicentre, randomised controlled trial done in 85 hospitals across 18 North American and European countries, enrolling 1,800 patients with de novo three-vessel disease (3VD) and/or left main coronary artery disease (LMCAD) randomized to revascularization strategy with CABG versus PCI in the SYNTAX trial. Patients were divided into two groups according to the prespecified threshold of 70 years old; elderly patients (>70 years) and non-elderly patients (≤70 years). The primary endpoint of this study was all-cause death at 10 years.

Results

Out of 1,800 patients, 575 patients (31.9%) were classified as elderly (>70 years). The mean age ± standard deviation (SD) of the elderly patients and the non-elderly patients was 75.8±3.6 years and 60.1±7.4 years, respectively. Of note, elderly patients were more frequently female than non-elderly patients (33.6% vs. 17.1%, p<0.001). As expected, the elderly patients had higher prevalence of chronic kidney disease (43.4% vs. 7.9%, p<0.001), had higher anatomical SYNTAX score (30.2±11.8 vs 28.0±11.2 p<0.001) when compared to those of the non-elderly patients.

Up to 10 years, all-cause death occurred in 42.7% and 18.9% in the elderly and non-elderly patients, respectively (Log-rank p<0.001). The cubic spline curve showed an exponentially increase in all-cause death at 10 years according to the increase of age both in the PCI arm and the CABG arm. At 10 years, there was no significant difference in the risk of all-cause death between CABG vs. PCI either in elderly patients (41.5% vs. 44.0%; Log-rank p=0.53) or non-elderly patients (16.6% vs. 21.1%; Log-rank p=0.051).

Conclusion

CABG and PCI were equipoise in terms of risk of all-cause death at 10 years in patients with de novo 3VD and/or LMCAD irrespective of their age when stratified according to the prespecified threshold of 70 years old.

Kaplan-Meier curves

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): German Foundation of Heart Research

Does expression of a human complement-regulatory protein on xenograft cells protect them from systemic complement activation?

BACKGROUND

There are many causes of systemic complement activation, which may have detrimental effects on a pig xenograft. Transgenic expression of one or more human complement-regulatory proteins (hCRPs), e.g., hCD46, provides some protection to the xenograft, but it is not known whether it protects the xenograft from the effects of systemic complement activation. We used wild-type (WT) pig aortic endothelial cells (pAECs) to activate complement, and determined whether the expression of hCD46 on a1,3galactosyltransferase gene-knockout (GTKO) pAECs protected them from injury.

METHODS

CFSE-labeled and non-labeled pAECs from a WT, a GTKO, or a GTKO/hCD46 pig were separately incubated with heat-inactivated pooled human serum in vitro. Antibody pre-bonded CFSE-labeled and non-labeled pAECs were mixed, and then incubated with rabbit complement. The complement-dependent cytotoxicity was measured by flow cytometry.

RESULTS

There was significantly less lysis of GTKO/CD46 pAECs (6%) by 50% human serum compared to that of WT (91%, p<0.001) or GTKO (32%, p<0.01) pAECs. The lysis of GTKO pAECs was significantly increased when mixed with WT pAECs (p<0.05). In contrast, there was no significant change in cytotoxicity of GTKO/CD46 pAECs when mixed with WT pAECs.

CONCLUSIONS

The expression of hCD46 protected pAECs from systemic complement activation.

Evidence for GTKO/β4GalNT2KO Pigs as the Preferred Organ-source for Old World Nonhuman Primates as a Preclinical Model of Xenotransplantation

BACKGROUND

Triple-knockout (TKO) pigs (in which expression of the 3 known pig carbohydrate xenoantigens has been deleted) are likely to be an optimal source of organs for transplantation into human recipients, many of whom do not have natural antibodies against TKO pig cells. However, old world monkeys, for example, baboons, have natural antibodies directed to TKO cells (to a "fourth" xenoantigen that is exposed after TKO).

METHODS

We measured (1) anti-pig IgM/IgG binding, and (2) complement-dependent cytotoxicity (CDC), by flow cytometry to α1,3-galactosyltransfearse gene-knockout (GTKO), GTKO/β4GalNT2KO (that do not express the "fourth" xenoantigen), and TKO pig peripheral blood mononuclear cells (PBMCs) using 72 baboon sera (30 specific pathogen-free [SPF], and 42 non-SPF baboons).

RESULTS

Mean IgM antibody binding to GTKO/β4GalNT2KO pig PBMCs was significantly lower than to GTKO or TKO pig PBMCs (P < 0.01). Mean IgG antibody binding to GTKO/β4GalNT2KO pig PBMCs was significantly lower than to TKO PBMCs (P < 0.01). Mean CDC of GTKO/β4GalNT2KO pig PBMCs was significantly lower than of GTKO or TKO pig PBMCs (P < 0.01). SPF baboon serum IgM and IgG binding to, and CDC of, GTKO/β4GalNT2KO or TKO PBMCs were significantly lower than non-SPF baboon sera (P < 0.01).

CONCLUSIONS

Although TKO pigs form the basis for proposed clinical trials of xenotransplantation, it is difficult to identify baboons with a low or negative CDC to TKO pigs. For pig-to-baboon organ transplantation, the use of GTKO/β4GalNT2KO pigs would be preferable. The use of SPF baboons as recipients might be a minor advantage.

Effect of intravenous immunoglobulin (IVIg) on primate complement-dependent cytotoxicity of genetically engineered pig cells: relevance to clinical xenotransplantation

Triple-knockout (TKO) pigs may be ideal sources of organs for clinical xenotransplantation because many humans have no preformed antibody to TKO pig cells. Intravenous immunoglobulin (IVIg) is widely used for severe infection or the treatment/prevention of antibody-mediated rejection in allotransplantation. Anti-pig antibodies in IVIg could be harmful in clinical xenotransplantation. It is unknown whether anti-TKO pig antibodies are present in IVIg. The main aim of this study was to investigate in vitro whether IVIg contains anti-TKO pig antibodies with cytotoxic effect to pig cells. Undiluted pooled human serum (HS) and five different commercial preparations of IVIg were tested for IgM and IgG binding to red blood cells (RBCs) from wild-type (WT), α1,3-galactosyltransferase gene-knockout (GTKO), and TKO pigs by flow cytometry. Complement-dependent lysis of IVIg against these pig pRBCs was measured by hemolytic assay. Pooled HS and 4 of 5 IVIg commercial preparations contained anti-pig IgG that bound to WT and GTKO pRBCs, but not to TKO pRBCs. One preparation of IVIg contained antibodies that bound to TKO pRBCs, but there was no cytotoxicity of IVIg to TKO pRBCs. The results suggest that IVIg administration to human recipients of TKO pig grafts would be safe. However, the specific preparation of IVIg would need to be screened before its administration.

Efficacy of ATG and Rituximab in capuchin monkeys (a New World monkey)-An in vitro study relevant to xenotransplantation

While Old World monkeys, for example, baboons, have antibodies against triple-knockout (TKO) pig cells, thus complicating pig organ transplantation studies, capuchin monkeys (a New World monkey) do not, thus more closely mimicking humans in respect to the response to TKO pig cells. Whether drugs such as anti-thymocyte globulin (ATG) and Rituximab are effective in capuchin monkeys remains uncertain. We measured the binding and cytotoxicity of ATG and Rituximab to human (n = 7), baboon (n = 7), and capuchin monkey (n = 5) peripheral blood mononuclear cells (PBMCs), T cells or B cells by flow cytometry.The effect in vitro of ATG in depleting PBMCs in capuchin monkeys and baboons was significantly less than in humans, but the depletion in capuchin monkeys was not significantly different from that in baboons. In contrast, the effect in vitro of Rituximab in depleting B cells in capuchin monkeys was very limited, and significantly less than in humans and baboons.Although capuchin monkeys mimic the human antibody response to TKO pig cells more closely than baboons, Rituximab had a minimal effect in capuchin monkeys in vitro. This observation may limit the value of New World Monkeys as recipients of pig organs, tissues, or cells in experimental studies of xenotransplantation or, indeed, in allotransplantation.

Old World Monkeys are less than ideal transplantation models for testing pig organs lacking three carbohydrate antigens (Triple-Knockout)

Triple-knockout (TKO) pigs (with added protective human transgenes) are likely to be optimal sources of organs for clinical organ xenotransplantation because many humans have minimal or no natural antibody to TKO pig cells. However, Old World monkeys (OWMs) have naturally-existing antibodies directed to TKO cells. We measured anti-pig IgM/IgG binding, and complement-dependent cytotoxicity to wild-type (WT), α1,3-galactosyltransferase gene-knockout (GTKO), and TKO pig peripheral blood mononuclear cells (PBMCs) using sera from humans, several OWMs, and two New World monkeys (NWMs). Furthermore, we compared survival of GTKO (n = 5) and TKO (n = 3) pig kidneys in baboons. OWMs had significantly greater IgM binding and cytotoxicity to TKO PBMCs than humans or NWMs. Mean anti-TKO IgM was significantly higher in OWMs and significantly lower in NWMs than in humans. Cytotoxicity of OWM sera to TKO PBMCs was significantly greater than of human serum, but there was no significant difference between human and NWM sera. The median survival of TKO pig kidneys (4 days) in baboons was significantly shorter than that of GTKO kidneys (136 days) (p < 0.05). Even though considered ideal for clinical xenotransplantation, the presence of naturally-existing antibodies to TKO pig cells in OWMs complicates the transplantation of TKO pig kidneys in OWMs.

Is interleukin-6 receptor blockade (tocilizumab) beneficial or detrimental to pig-to-baboon organ xenotransplantation?

The interleukin (IL)-6/IL-6 receptor-α (IL-6Rα)/signal transduction and activation of the transcription 3 (STAT3) pathway plays an important role in inflammation. Anti-human IL-6Rα blockade by tocilizumab (TCZ) has been used in pig-to-baboon organ xenotransplant models, but whether it is beneficial remains uncertain. After xenotransplant, there were significant increases in both baboon and pig IL-6 in the baboon serum, especially in baboons that received TCZ before xenotransplant. In vitro observations demonstrated that human, baboon, and pig IL-6 can activate the IL-6/IL-6Rα/STAT3 pathway in human, baboon, and pig cells, respectively. Activation of the IL-6/IL-6Rα/STAT3 pathway was blocked by TCZ in human and baboon cells but not in pig cells (ie, pig IL-6R). Siltuximab (human IL-6 inhibitor) bound to both human and baboon, but not pig, IL-6 and suppressed activation of the IL-6/IL-6Rα/STAT3 pathway. These results indicate that TCZ and siltuximab do not cross-react with pig IL-6R and pig IL-6, respectively. Rapamycin partially inhibited human, baboon, and pig IL-6/IL-6Rα/STAT3 pathways and suppressed inflammatory gene expression. TCZ treatment increased serum IL-6 because it could no longer bind to baboon IL-6Rα. We suggest that increased serum IL-6 may be detrimental to the pig xenograft because it is likely to bind to pig IL-6R, resulting in activation of pig cells.

Induction of diabetes in cynomolgus monkey with one shot of analytical grade streptozotocin

BACKGROUNDS

Streptozotocin (STZ)- induced diabetic monkey is a wide used preclinical animal model for the investigation of diabetes such as islet transplantation and development of diabetic drugs. There are serious side effects of this method, including nausea, emesis, weight loss, liver damage, renal failure, and metabolic acidosis. In order to reduce the side effects, diabetic monkeys were induced using clinical-grade STZ. However, clinical-grade STZ is not available in China. Here, we establised a method by using 100 mg/kg analytical-grade STZ to induce complete diabetes in cynomolgus monkey without generating adverse effects to liver and renal.

METHODS

Three cynomolgus monkeys were used in this study. 100 mg/kg STZ dissolved in normal saline and infused through vein line in 5 minutes after indwelling catheter in the carotid artery and jugular vein. After the STZ administration, blood glucose levels were examined every 1 or 2 hours in the first 48 hours. Then, blood glucose levels were examined twice per day during the first week after the STZ injection. Insulin and C-peptide levels were measured by ELISA. Blood chemistry of hepatic and renal function tests were performed. Insulin and glucagon expression in the islet of diabetic monkey and normal monkey were examined by immunohistochemistry assays.

RESULTS

The stimulated C-peptide level (Intravenous glucose tolerance test) which is less than 0.5 ng/mL, the triphasic blood glucose response and the destroyed β cell suggested the complete induction of diabetes model. No apparent adverse effects were observed including no signs of vomiting and toxicity after STZ injection.

CONCLUSION

In summary, we established a safe and reproducible STZ-induced diabetic cynomolgus monkey model for islet transplantation which will be used to develop novel approaches for the treatment of diabetes.

P1528 Prognostic impact of pulmonary arterial wave reflection in heart failure

Background

Pulmonary hypertension (PH) is prevalent and is associated with adverse outcomes in heart failure. The pathophysiology of PH is heterogeneous, including pre-capillary PH and combined pre- and post-capillary PH. The latter PH has been reported in experimental studies to cause wave reflection in pulmonary circulation, putting additional burden on right ventricle. This study tested the hypothesis that separating wave reflection would enhance risk stratification in heart failure.

Methods

This study included 152 patients with clinical stable heart failure associated with PH who were referred to echocardiography for hemodynamic assessment (age = 72 ± 13 years old, ejection fraction = 49 ± 21%). Pulmonary arterial wave reflection was characterised by separating PA pressure waveform into forward (Pf) and backward pressure (Pb) waves, based on the concept of wave intensity. PA pressure waveform was estimated from continuous Doppler tracing of tricuspid regurgitation. Flow velocity was measured by pulse Doppler at right ventricular outflow tract. Outcome data was obtained by reviewing medical charts. The endpoint was hospitalization for worsening heart failure (WHF).

Results

Figure A compares PA pressure waveforms (total and separated waves) obtained from 2 patients with and without WHF event. The patient with event had higher total pressure associated with late peak than the patient without event. Pb appeared later than Pf; it was markedly higher in the patient with event than the patient without event, although Pf was similar between both patients. Kaplan-Meier analysis demonstrated a significant separation of survival curves stratified by Pb (chi-square = 25.1, p &lt; 0.001, figure B). During follow-up period of 1.5 ± 1.8 years, 65 patients (43%) experienced the endpoint. Sequential Cox analysis revealed that PASP remained significant after adjusted for left ventricular ejection fraction and E/e’ (hazard ratio = 1.017, p = 0.019). Pb also remained significant after the same adjustment (hazard ratio = 1.066, p = 0.003); the addition of Pb to a baseline model resulted in greater increase in predictive power than the addition of PASP (model chi-square: from 27.4 (baseline), to 37.6 (p = 0.004) for Pb, to 31.6 (p = 0.027) for PASP, figure C)

Conclusions

Pressure wave reflection in pulmonary artery is associated with early decompensation in heart failure.

Abstract P1528 Figure.

P1480 A case of triple left ventricular aneurysms diagnosed by CT and echocardiography

【Background】

Left ventricular aneurysms is complication of myocardial infarction (MI) that can lead to death or serious morbidity. False aneurysm is rare complications of myocardial infarction or iatrogenic perforation and represent a contained myocardial rupture. False aneurysm does not contain all the three layers of the myocardium and is frequently lined by pericardium and mural thrombus. Definitive diagnosis is achieved by echocardiography, computed tomography (CT), angiography, or magnetic resonance imaging. Coexistence of true and false aneurysms is rare.

【Case】 A 58 years old man with a history of hypertension and MI was referred to our hospital for aneurysmectomy. During the course of prior MI, he got fever and pericardial effusion.

CT revealed that three left ventricular aneurysms were present. Also, three aneurysms were connected by narrow ducts each other. Transthoracic echocardiography (TTE) revealed that three ventricular aneurysms were connected via acceleration blood flow which swirling in the spherical aneurysm. We determined that this triple ventricular aneurysms were at high risk for rupture, so we performed surgery.

The postoperative course was good and he was discharged without any complications.

【Discussion】

False aneurysms occur after hemorrhagic dissection into an area of transmural infarction and most commonly result in free intrapericardial rupture of the heart, cardiac tamponade, and death. Rarely, if the overlying pericardium becomes adherent to the epicardium along the surface of the infarct, it can contain the rupture.

We were able to evaluate the mechanism of development with triple left ventricular aneurysms using CT and TTE. We could know about spatial comprehension of triple aneurysms using CT. False aneurysms were restricted enlargement due to stiff pericardium because of complicating Dressler syndrome. We hypothesis that aneurysms were enlarging in the direction of the base of heart in the adhered pericardium space.

We were able to evaluate the thickness of aneurysms and blood flow condition using TTE. TTE revealed that the wall of aneurysm was fragile. Multimodality imaging like TTE or cardiac CT are useful diagnostic methods in this case.

Abstract P1480 Figure. Triple aneurysms

1638 A case of capturing changes in interatrial blood flow and anatomical structure during percutaneous PFO closure with platypnea orthodeoxia syndrome using intra-cardiac echocardiography

Background

Platypnea–orthodeoxia syndrome (POS) is an uncommon condition characterized by positional dyspnea and hypoxemia due to intracardiac right-to-left shunting through a patent foramen ovale (PFO). The most commonly associated conditions included pneumonectomy, ascending aortic dilation, and arch surgery, as previously reported. Percutaneous closure of PFO is useful treatment for POS.

Case

A 76 year old man used home oxygen therapy because of unexplained hypoxemia. A decrease in blood oxygen saturation was observed in sitting and standing positions. The patient was diagnosed as "POS" because a shunt blood flow with PFO and atrial septal aneurysm (ASA) and eustachian valve was observed at transesophageal echocardiography. He was admitted for the purpose of percutaneous PFO closure.

He was treated with intra-cardiac echocardiography (ICE) guidance under local anesthesia because of poor lung function.

PFO closure was performed successfully with 30mm AMPLATZER Cribriform. The ICE findings prior to PFO closure showed a right-to-left shunt blood flow through the PFO in the sitting position but almost disappeared after closure. Furthermore, it was observed that the aortic artery compression was stronger in the sitting position than in the supine position with right-to-left shunt blood flow. After PFO closure, hypoxia associated with postural change improved and patient’s symptom as shortness of breath also significantly improved.

Discussion

POS is a position-dependent condition of dyspnea and hypoxemia due to right-to-left shunting. It often remains unrecognized in clinical practice, possibly because of its complex underlying pathophysiology. It is considered that the cause of POS in this patient was multiple factors such as ASA, aortic displacement, and venous valve remnant. In addition, being able to observe the change of the atrium due to compression from the aortic artery using ICE during the operation was very significant to explain the mechanism of POS.

Abstract 1638 Figure. Intra-cardiac echocardiography