Early and Late Surgical Outcomes after Geometrical Infarct Exclusion for Post-Infarct Ventricular Septal Perforation

PURPOSE

Ventricular septal perforation (VSP) is a critical complication of acute myocardial infarction. Various surgical procedures for it have been developed; however, surgical outcomes remain unsatisfactory. In 2010, we introduced geometrical infarct exclusion (GIE) as a modification of the Komeda-David technique. This retrospective study compared the surgical outcomes of our geometric infarct exclusion technique to those of other surgical procedures.

METHODS

This study included 38 patients who underwent surgery for VSP. They were divided into patients who underwent GIE (GIE group; n = 17) and those who underwent other procedures (non-GIE group; n = 21). The clinical outcomes of the two groups were compared.

RESULTS

Operation, cardiopulmonary bypass, and cardiac arrest times in the GIE group were significantly longer than those in the non-GIE group (p <0.001). A residual shunt was observed in one patient (5.8%) in the GIE group and eight (38.0%) in the non-GIE group (p = 0.026). No patients in the GIE group required a reoperation for the residual shut, while two patients required it in the non-GIE group (p = 0.492). Operative mortality was insignificantly different between the two groups.

CONCLUSION

Geometric infarct exclusion has a longer procedural time than does other surgical procedures but can reduce the rates of residual shunts and reoperations.

Validity of direct bilateral axillary arterial cannulation in emergency surgery for acute type A aortic dissection

BACKGROUND AND AIM OF THE STUDY

To assess the validity and long-term outcomes of direct bilateral axillary arterial cannulation for acute type A aortic dissection.

METHODS

Between 2003 and 2020, 208 consecutive patients with acute type A aortic dissection underwent emergency surgical repair. Cardiopulmonary bypass was attempted to establish direct bilateral axillary arterial cannulation and bicaval drainage. Antegrade selective cerebral perfusion was established by axillary perfusion and direct cannulation of the left common carotid artery.

RESULTS

Ascending aortic, partial arch, and extended total aortic arch replacement were performed in 50 (24.0%), 7 (3.4%), and 151 (72.6%) patients, respectively. Aortic root surgery and coronary artery bypass grafting were performed concomitantly in 23 and seven patients, respectively. Cardiopulmonary bypass was attempted only through bilateral axillary cannulation in all patients but was successful in 13 (6.3%) patients without bilateral axillary cannulation. No postoperative complications occurred related to this technique. There were seven hospital deaths (early mortality rate, 3.4%). Five patients had postoperative reoperation for bleeding, and nine (4.3%) were transferred to other hospitals due to postoperative permanent cerebral infarction, particularly two with arm ischemia. The 10-year survival rate of patients who underwent emergency surgical repair with this technique was 71.4%.

CONCLUSIONS

Direct bilateral axillary arterial cannulation followed by selective cerebral perfusion was successful in 93.7% of patients and this may be an optimal solution for providing stable outcomes after emergency surgery for acute type A aortic dissection. However, we experienced two complications of arm ischemia, attention should be paid to potential arm ischemia.

Impact of the no-touch harvesting technique on the vessel diameter of saphenous vein grafts for coronary artery bypass grafting

Objectives

To explore the impact of the no-touch harvesting technique on the vessel diameter of saphenous vein grafts.

Methods

This retrospective, single-center study enrolled 166 patients who underwent isolated coronary artery bypass grafting using saphenous vein grafts. Saphenous vein grafts were harvested conventionally in 83 patients (conventional group) and using the no-touch technique in 83 patients (no-touch group). We analyzed graft patency and the vessel diameters of saphenous vein grafts in the pre- and postoperative states. The diameter mismatch between the saphenous vein grafts and the coronary artery at the anastomotic site was also measured; preoperative diameter was measured using ultrasound imaging, and the postoperative diameter was measured using electrocardiogram-gated enhanced computed tomography.

Results

A total of 135 saphenous vein grafts (66 and 69 grafts in the conventional and no-touch groups, respectively) were evaluated for postoperative patency. Graft patency was equivalent in the 2 groups (conventional, 96.9% vs no-touch, 100%; P = .24). A detailed evaluation was performed in 109 saphenous vein grafts (52 and 57 grafts in the conventional and no-touch groups, respectively). Saphenous vein graft diameter was significantly distended in the conventional group (preoperative, 2.6 ± 0.7 mm vs postoperative, 3.4 ± 0.5 mm; P < .0001). However, saphenous vein graft diameter did not change in the no-touch group (preoperative, 2.9 ± 0.4 mm vs postoperative 2.8 ± 0.4 mm, P = .33). The diameter mismatch was significantly smaller in the no-touch group (conventional 1.4 ± 0.6 mm vs no-touch 1.0 ± 0.4 mm, P < .0001).

Conclusions

The no-touch technique avoids the expansion of graft diameter and diameter mismatch between the saphenous vein grafts and coronary artery.

Intimal-protected adventitial inversion technique accelerates the obliteration of a patent false lumen

BACKGROUND AND AIMS

The optimal procedure for reconstructing the dissected aortic stump for acute type A dissection remains controversial. We routinely used the intimal-protected adventitial inversion technique (iPAIT), a modified adventitial inversion technique, to protect the fragile intima by inserting a graft and assessed the safety and efficacy of this technique.

METHODS

Between August 2008 and April 2020, 146 consecutive patients with acute type A dissections underwent thoracic aortic surgery in our hospital. Extended total aortic arch replacement was performed in 119 patients (81.5%). Sixty-nine patients underwent treatment for distal aortic anastomosis with the iPAIT. To compare the iPAIT to a historical control, we assessed 69 iPAIT patients and 25 patients who underwent total arch replacement using gelatin-resorcinol-formaldehyde (GRF) glue.

RESULTS

Hospital mortality was 2.9% in the iPAIT group and 8.0% in the GRF group. Perioperative characteristics were similar between the two groups. However, postoperative computed tomography revealed that the obliteration rate was significantly higher in the iPAIT group (60/66, 90.9%) than in the GRF group (15/23, 65.2%) (p = .01), not including the patients who had died or developed severe renal dysfunction. The 8-year aortic event-free survival rate in the iPAIT group (81.3%) was significantly higher than that in the GRF group (47.4%).

CONCLUSIONS

The use of this technique for acute type A dissections resulted in a low mortality rate and demonstrated promising midterm survival and may accelerate the obliteration of a patent false lumen and prevent late aortic events.

Early and Long-Term Outcomes of Transcatheter Aortic Valve Replacement for Selected Nonagenarians in Japan

BACKGROUND

Transcatheter aortic valve implantation (TAVI) is increasingly being performed in very elderly patients, although its efficacy and validity remain unclear. This study evaluated real-world TAVI outcomes in Japanese nonagenarians with severe aortic stenosis.Methods and Results:This single-center study retrospectively assessed the early and long-term clinical outcomes of TAVI in nonagenarians (n=35) and in patients aged <90 years (group Y; n=171). There were no in-hospital deaths in either group. The device success rate and early safety were comparable between the 2 groups. The 5-year rates of freedom from cardiac events and deaths were equivalent in both groups. The cumulative survival rate at 5 years was non-significantly lower in nonagenarians (32.6% in nonagenarians vs. 57.5% in patients aged <90 years, P=0.49). There were no differences in the 5-year survival between nonagenarians after TAVI and the sex- and age-matched populations (P=0.18). The Cox regression model revealed that lower hemoglobin levels were associated with all-cause mortality (P=0.02), and age ≥90 years was not associated with all-cause mortality.

CONCLUSIONS

The early and long-term clinical outcomes of TAVI for selected Japanese nonagenarians were comparable to those in patients aged <90 years. Nonagenarians who underwent TAVI achieved an acceptable prognosis compared to the sex- and age-matched population; thus, TAVI appears to be effective for treating aortic stenosis in Japanese nonagenarians.

[Subcutaneous Bronchogenic Cyst in the Anterior Chest Diagnosed before Coronary Artery Bypass Grafting:Report of a Case]

A 65-year-old woman was transported to our hospital by ambulance because of severe dyspnea. She had had a subcutaneous tumor on her anterior chest since her childhood. Coronary angiography revealed three vessel disease with significant stenosis in the left main trunk. Excision of anterior chest tumor, 70×60×50 mm in size, was performed before coronary artery bypass grafting( CABG). It was a unilocular cyst adhering to the sternum, and was composed of ciliated epitheliums, goblet cells and smooth muscle cells. Based upon the existence of smooth muscle cells, the tumor was diagnosed as bronchogenic cyst. CABG was performed through mid-sternum about two months after the tumor excision, and the postoperative course was uneventful.

Perivascular Adipose Tissue Is a Major Source of Nitric Oxide in Saphenous Vein Grafts Harvested via the No-Touch Technique

Background

Saphenous vein grafts (SVGs) are broadly used in coronary artery bypass grafting despite their inferior patency compared with arterial grafts. Recently, the no‐touch technique (NT), in which an SVG is harvested with a pedicle of perivascular adipose tissue (PVAT) without conduit distension, was shown to improve long‐term patency compared with conventional preparation (CV), wherein outer tissue is removed with distension. The NT was also reportedly associated with reduced atherosclerosis. Although endothelial damage provoked by conventional distension may underlie poor patency when CV is performed, the precise mechanisms underlying the salutary effects of the NT have been unclear.

Methods and Results

Residual SVGs prepared with CV (CV‐SVGs) or NT (NT‐SVGs) were obtained during coronary artery bypass grafting. Nitric oxide (NO₂⁻/NO₃⁻ (NO_x)) levels after 24 hours of tissue culture were quantified. The protein expression and localization were analyzed. The isometric force of SVG strips was measured. NT‐SVGs showed superior NO_x production to CV‐SVGs. PVAT generated the majority of NO_x in NT‐SVGs. PVAT highly expressed arginosuccinate synthase 1, a rate‐limiting enzyme in the molecular circuit for NO synthesis, thereby continuously providing the substrate for NO. A substantial level of endothelial NO synthase was also expressed in PVAT. Pharmacological inhibition of arginosuccinate synthase 1 or endothelial NO synthase significantly suppressed the NO_x production in NT‐SVGs. PVAT induced vasorelaxation through NO production, even in the endothelium‐denuded SVG strips.

Conclusions

Preserving PVAT was predominantly involved in the superior NO_x production in NT‐SVGs. Since NO plays crucial roles in suppressing atherosclerosis, this mechanism may greatly contribute to the excellent patency in NT‐SVGs.

OUP accepted manuscript

OBJECTIVES

METHODS

RESULTS

CONCLUSIONS

Clinical registration number

Preoperative evaluation of aortic calcification by computed tomography in thoracic aortic disease

BACKGROUND

Computed tomography (CT) is a useful tool for the identification of calcified lesions in the aorta. However, no quantitative evaluation has been established to assess the applicability of simple anastomosis preoperatively. We conducted this retrospective study to establish a reference range of maximal CT attenuation values for application of simple anastomosis.

METHODS

A total of 122 consecutive patients underwent replacement of the thoracic aorta between 2007 and 2011, excluding those with acute aortic dissection. The patients were divided into two groups: those who underwent simple anastomosis (simple group: n = 105), and those who required endarterectomy before anastomosis (manipulation group: n = 17). The maximal CT attenuation values at the anastomosis site were calculated by imaging software.

RESULTS

The mean maximal CT attenuation values (Hounsfield unit [HU]) was significantly higher in the manipulation group (638.1 ± 269.5 [166-1304]) than in the simple group (94.7 ± 171.5 [0-790]; p < .0001). The maximal CT attenuation values enabled us to predict the simple anastomosis with the area under the receiver operating characteristic curve of 0.96 (p < .0001). The cut-off value was 325 HU (sensitivity 94.1%, specificity 81.7%). The 10-year survival rate was significantly lower in the manipulation group (11.8%) than in the simple group (43.2%). In the multivariate analysis, age (hazard ratio [HR]: 1.073), hypertension (HR: 2.382), and maximal CT attenuation values (HR: 1.001) were independently associated with long-term mortality.

CONCLUSIONS

Preoperative evaluation of the maximal CT attenuation values is a useful tool in predicting whether simple anastomosis is applicable or not. Maximal CT attenuation values is a risk factor for long-term mortality.

Preserving the endothelium in saphenous vein graft with both conventional and no-touch preparation

Background

Despite the inferior patency compared to arterial grafts, a saphenous vein graft (SVG) is widely used for coronary artery bypass grafting (CABG). A lower atherosclerosis rate and higher patency have been reported for SVG obtained via the no-touch technique (NT) than via conventional preparation (CV). Although CV-mediated endothelial dysfunction is implied, the precise mechanism underlying the higher patency with NT is poorly understood.

Methods

Human residual SVGs during CABG and SVG sections after autopsy were analyzed. The endothelial surface was observed using scanning electron microscopy (SEM) and blindly compared between CV and NT. The endothelial integrity was also analyzed with immunohistochemistry.

Results

Unexpectedly, the hyperfine structure on SEM was comparable between CV and NT before grafting, and microvillus, a characteristic of endothelium, was indistinguishable between them. Von Willebrand Factor, an endothelial marker, was equally detected throughout the vascular wall in both groups from residual and postmortem sections.

Conclusions

The morphological integrity of the endothelium was successfully preserved in SVG with CV, even at an ultrastructural level. Although its functionality remains to be addressed, other factors than the endothelium may be involved in the high patency obtained by NT. The present findings suggest that the characteristics of NT and surgical methodology should be reconsidered.

Impact of acute kidney injury on prognosis of chronic kidney disease after aortic arch surgery

OBJECTIVES

Postoperative acute kidney injury (AKI) is a common complication associated with increased long-term mortality after cardiothoracic surgery. However, AKI after total aortic arch replacement (TAR) is not well studied. This study aimed to investigate the prognosis and impact of AKI on the long-term outcomes of chronic kidney disease (CKD) patients undergoing TAR.

METHODS

We included 208 patients who underwent TAR between September 2003 and December 2014. Patients were divided into a CKD (n = 83, 40%) and non-CKD (n = 125, 60%) group. The definition of AKI followed the Risk, Injury, Failure, Loss of kidney function and End-stage kidney disease (RIFLE) criteria. Independent risk factors for all-cause death and AKI were identified with multivariable analysis.

RESULTS

Postoperative AKI was observed in 24 patients (29%) and 39 patients (31%) of CKD and non-CKD groups, respectively. The survival rate of CKD patients was significantly lower than that of non-CKD patients (P = 0.02). Among CKD patients, the 5-year survival rate was 57% in those with AKI group and 92% in those without AKI; prognosis was significantly poorer in patients with AKI (P = 0.001). In the non-CKD group, there was no difference in prognosis between patients with or without AKI (P = 0.77). Multivariable logistic regression analysis revealed that intraoperative blood loss of ≥600 ml was the only predictor of AKI in the CKD group (odds ratio 4.32, P = 0.04).

CONCLUSIONS

CKD is associated with reduced long-term survival after TAR. Postoperative AKI strongly influences long-term survival in CKD patients only.

Hypoxic-conditioned cardiosphere-derived cell sheet transplantation for chronic myocardial infarction

OBJECTIVES

Cell therapy provides a suitable environment for regeneration through paracrine effects such as secretion of growth factors. Cardiosphere-derived cells (CDCs) have a high capacity for growth factor secretion and are an attractive target for clinical applications. In particular, a cell sheet technique was reported to have clinical advantages by covering a specific region. Here, we examined the effect of the hypoxic-conditioned (HC) autologous CDC sheet therapy on a rabbit chronic myocardial infarction model.

METHODS

CDC sheet function was assessed by the enzyme-linked immunosorbent assay and quantified by polymerase chain reaction in vitro (days 1-3 of conditioning). The rabbit chronic myocardial infarction model was established by left coronary ligation. Autologous CDCs were isolated from the left atrial specimen; CDC sheets with or without 2-day HC were transplanted onto the infarcted hearts at 4 weeks. The cardiac function was assessed by an echocardiography at 0, 4 and 8 weeks. A histological analysis of the host hearts was performed by tomato lectin staining at 8 weeks.

RESULTS

The optimal HC duration was 48 h. HC significantly increased the mRNA expression levels of VEGF and ANG2 on day 2 compared to the normoxic-conditioned (NC) group. The HC group showed significant improvement in the left ventricular ejection fraction (64.4% vs 58.8% and 53.4% in the NC and control) and a greater lectin-positive area in the ischaemic region (HC:NC:control = 13:8:2).

CONCLUSIONS

HC enhances the paracrine effect of a CDC sheet on angiogenesis to improve cardiac function in the chronic myocardial infarction model, which is essential for cardiomyocyte proliferation during cardiac regeneration.

Effect of Autotransfusion Using Intraoperative Predonated Autologous Blood on Coagulopathy during Thoracic Aortic Surgery: A Randomized Controlled Trial

Background: Intraoperative predonated autologous blood transfusion is thought to replenish platelets and coagulation factors and ameliorate coagulopathy. This study aimed to evaluate whether intraoperative predonated autotransfusion improves coagulopathy during thoracic aortic surgery.

Methods: Patients who underwent thoracic aortic surgery were randomized into two groups as follows: those who received intraoperative predonated blood (group A: n = 31) and those who did not receive (group N: n = 22). In group A, autologous blood was retransfused immediately after cessation of cardiopulmonary bypass (c-CPB).

Results: The mean intraoperative allogenic blood or blood product transfusion requirements were significantly lesser in group A than in group N (packed red blood cells [RBCs]: 6.3 ± 5.1 vs. 9.1 ± 4.3 units, p = 0.04; fresh frozen plasma [FFP]: 3.0 ± 4.1 vs. 6.1 ± 5.7 units, p = 0.03). After c-CPB, hemoglobin (Hb) level, platelet count, and coagulopathy became significantly worse than those at the start of surgery in both the groups. However, the values significantly improved 30 min after c-CPB only in group A. Renal function was significantly worse in group N.

Conclusions: Intraoperative predonated autotransfusion significantly improved coagulopathy, with reduced allogeneic blood transfusion volume during thoracic aortic surgery. Furthermore, reduction of allogeneic blood transfusion may reduce the adverse effects on renal function.

Relief of vasospasm with fasudil after off-pump coronary artery bypass grafting: a case study

Background

Coronary vasospasm after coronary artery bypass grafting (CABG) is a rare but potentially lethal complication. It is often refractory to several vasodilators. We report a case of refractory coronary vasospasm relieved by fasudil injection.

Case presentation

A 74-year-old woman who had three instances of in-stent stenosis at the left anterior descending artery (LAD) was referred for CABG treatment. Preoperative coronary angiography showed 90% in-stent stenosis of the proximal LAD and 75% stenosis of the diagonal branch. We performed a left internal thoracic artery (LITA)-LAD bypass and a right internal thoracic artery (RITA) diagonal branch bypass. After anastomosis, transit time flow measurement revealed poor blood flow of LITA-LAD bypass even after re-anastomosis. We performed coronary angiography and detected a vasospasm in the native coronary arteries, which was not relieved using conventional vasodilators (calcium channel blockers, isosorbide dinitrate, and nicorandil) However, we were able to relieve the coronary vasospasm by administering fasudil (a Rho kinase inhibitor) injection without causing systemic hypotension.

Conclusions

Fasudil may be an important vasodilator, especially in cases of coronary vasospasm after CABG.

Short- and long-term outcomes of intramyocardial implantation of autologous bone marrow-derived cells for the treatment of ischaemic heart disease

Objectives

Ischaemic heart disease remains a major cause of death in Japan. We have implanted autologous bone marrow-derived cells locally into the ischaemic region as a therapy in addition to coronary artery bypass grafting since 1999. We describe the outcomes of our cell therapy for ischaemic heart disease.

Methods

Eleven patients underwent local implantation of bone marrow-derived cells into the ischaemic region during coronary artery bypass grafting. Clinical outcomes during the acute and chronic phases were recorded.

Results

In the acute phase, no adverse effects were observed. Left ventricular ejection fraction values were not significantly different before and after treatment. Seven of the 11 patients showed improved blood perfusion in the area of cell therapy 1 month after treatment. In the chronic phase, 5 of 11 patients exhibited improved regional blood flow 1 year after treatment. Overall survival at 1, 5 and 10 years was 100%, 83.3% and 83.3%, respectively. Freedom from major adverse cardiac and cerebrovascular events at 1, 5 and 10 years was 100%, 80.8% and 80.8%, respectively. Death from all causes or freedom from major adverse cardiac and cerebrovascular events at 1, 5 and 10 years was 100%, 64.6% and 64.6%, respectively.

Conclusions

Local implantation of bone marrow-derived cells in patients with ischaemic heart disease is safe and feasible. Cell therapy is a therapeutic option for otherwise untreatable ischaemic heart disease.

Comparison of Cell Therapy and Cytokine Therapy for Functional Repair in Ischemic and Nonischemic Heart Failure

Although cell therapy shows great promise as a new therapeutic strategy for heart failure, its precise mechanisms remain unclear. Furthermore, the advantages of cell therapy over conventional cytokine therapy have yet to be clarified. This study was designed to compare the functional improvement achieved by cell therapy and cytokine therapy in both ischemic and nonischemic heart failure experimental models. Ischemic heart failure was induced by ligating the left anterior descending artery, and nonischemic heart failure was induced by an IP injection of doxorubicin, respectively, in mice. After establishing the heart failure models, mice were randomly given a single intramyocardial injection of 2 × 105 c-kit-positive bone marrow stem cells (cell therapy), hepatic growth factor (cytokine therapy), or PBS injection only (control). In the ischemic heart failure model, both cell therapy and cytokine therapy increased the vessel density significantly, inhibited apoptosis of myocytes, and decreased the fibrotic area in the ischemic myocardium, which resulted in a significant increase in the survival rate and enhancement of the cardiac function of these mice (p < 0.05 vs. control therapy). In the nonischemic heart failure model, significant increases in the survival rate and cardiac function were achieved by cell therapy (p < 0.05 vs. control therapy), but not by cytokine therapy, although cytokine therapy inhibited the fibrosis and apoptosis of the cardiomyocytes. Both cell therapy and cytokine therapy are alternative treatments for ischemic heart failure. However, cell therapy is more effective for the treatment of nonischemic heart failure than cytokine therapy achieved by the administration of a single growth factor.

Comparison of Intramyocardial and Intravenous Routes of Delivering Bone Marrow Cells for the Treatment of Ischemic Heart Disease: An Experimental Study

The implantation of bone marrow cells (BMCs) into ischemic heart after myocardial infarction can induce angiogenesis and improve heart function. We compared the advantages of delivering BMCs intramyocardially and intravenously. An acute myocardial infarction model was created by the ligation of left anterior descending artery in female Dark Agouti rats. The rats were then randomly divided into four treatment groups: one given an intramyocardial injection of phosphate-buffered saline (PBS group), one given an intravenous injection of 2 × 107 BMCs from male rats (IV group), one given an intramyocardial injection with total of 2 × 107 BMCs from male rats at four points in the infarction area (IM group), and one given an intravenous injection of 10-fold the number of BMCs from male rats (10xIV group). Quantitative analysis of the SRY gene by real-time PCR showed that the survival of BMCs in the infarcted area was significantly higher in the IM group than in the IV and 10xIV groups, 3 days after treatment (p < 0.05), but not thereafter. However, the blood flow in the infarcted myocardium was significantly better in the IM and 10xIV groups than in the PBS and IV groups 14 days after treatment (p < 0.05). Echocardiography showed that the LVEF continued to decrease in the PBS and IV groups, but was stable after 3 days in the IM and 10xIV groups. By 14 days after treatment, the LVEF was significantly higher in the IM and 10xIV groups than in the PBS and IV groups (p < 0.01). Our results showed that BMCs were more effective delivered intramyocardially than intravenously for inducing angiogenesis and repairing injured myocardium.

Age-related increase in Wnt inhibitor causes a senescence-like phenotype in human cardiac stem cells

Aging of cardiac stem/progenitor cells (CSCs) impairs heart regeneration and leads to unsatisfactory outcomes of cell-based therapies. As the precise mechanisms underlying CSC aging remain unclear, the use of therapeutic strategies for elderly patients with heart failure is severely delayed. In this study, we used human cardiosphere-derived cells (CDCs), a subtype of CSC found in the postnatal heart, to identify secreted factor(s) associated with CSC aging. Human CDCs were isolated from heart failure patients of various ages (2-83 years old). Gene expression of key soluble factors was compared between CDCs derived from young and elderly patients. Among these factors, SFRP1, a gene encoding a Wnt antagonist, was significantly up-regulated in CDCs from elderly patients (≥65 years old). sFRP1 levels was increased significantly also in CDCs, whose senescent phenotype was induced by anti-cancer drug treatment. These results suggest the participation of sFRP1 in CSC aging. We show that the administration of recombinant sFRP1 induced cellular senescence in CDCs derived from young patients, as indicated by increased levels of markers such as p16, and a senescence-associated secretory phenotype. In addition, co-administration of recombinant sFRP1 could abrogate the accelerated CDC proliferation induced by Wnt3A. Taken together, our results suggest that canonical Wnt signaling and its antagonist, sFRP1, regulate proliferation of human CSCs. Furthermore, excess sFRP1 in elderly patients causes CSC aging.

Hypoxic preconditioning of human cardiosphere-derived cell sheets enhances cellular functions via activation of the PI3K/Akt/mTOR/HIF-1α pathway

Cell sheet technology is a promising therapeutic strategy for the treatment of ischemic diseases such as myocardial infarction. We recently developed a novel protocol, termed "hypoxic preconditioning," capable of augmenting the therapeutic efficacy of cell sheets. Following this protocol, the pro-angiogenic and anti-fibrotic activity of cell sheets were enhanced by brief incubation of cell sheets under hypoxic culture conditions. However, the precise molecular mechanism underlying the hypoxic preconditioning of cell sheets is unclear. In the present study, we examined signal transducers in cell sheets to identify those responsive to hypoxic preconditioning, using cardiosphere-derived cell (CDC) sheets. We initially tested whether sheet-like structures were suitable for hypoxic preconditioning by comparing them with individual cells. Hypoxic preconditioning was more effective in sheeted cells than in individual cells. Expression of hypoxia inducible factor-1α (HIF-1α) and mammalian target of rapamycin (mTOR) were induced upon hypoxic preconditioning of cell sheets, as was the phosphoinositide 3-kinase (PI3K)/Akt pathway. In addition, hypoxic preconditioning increased phosphorylation of epidermal growth factor receptor (EGFR) and heat shock protein 60 (HSP60) in CDC sheets. Our findings provide novel insights into the utility of hypoxic preconditioning in cell sheet-based technologies for the treatment of ischemic diseases.

Influence of aging on the quantity and quality of human cardiac stem cells

Advanced age affects various tissue-specific stem cells and decreases their regenerative ability. We therefore examined whether aging affected the quantity and quality of cardiac stem cells using cells obtained from 26 patients of various ages (from 2 to 83 years old). We collected fresh right atria and cultured cardiosphere-derived cells (CDCs), which are a type of cardiac stem cell. Then we investigated growth rate, senescence, DNA damage, and the growth factor production of CDCs. All samples yielded a sufficient number of CDCs for experiments and the cellular growth rate was not obviously associated with age. The expression of senescence-associated b-galactosidase and the DNA damage marker, gH2AX, showed a slightly higher trend in CDCs from older patients (≥65 years). The expression of VEGF, HGF, IGF-1, SDF-1, and TGF-b varied among samples, and the expression of these beneficial factors did not decrease with age. An in vitro angiogenesis assay also showed that the angiogenic potency of CDCs was not impaired, even in those from older patients. Our data suggest that the impact of age on the quantity and quality of CDCs is quite limited. These findings have important clinical implications for autologous stem cell transplantation in elderly patients.

Cardiosphere-derived cell sheet primed with hypoxia improves left ventricular function of chronically infarcted heart

Cardiosphere-derived cells (CDCs) isolated from postnatal heart tissue are a convenient and efficientresource for the treatment of myocardial infarction. However, poor retention of CDCs in infarcted hearts often causes less than ideal therapeutic outcomes. Cell sheet technology has been developed as a means of permitting longer retention of graft cells, and this therapeutic strategy has opened new avenues of cell-based therapy for severe ischemic diseases. However, there is still scope for improvement before this treatment can be routinely applied in clinical settings. In this study, we investigated whether hypoxic preconditioning enhances the therapeutic efficacy of CDC monolayer sheets. To induce hypoxia priming, CDC monolayer sheets were placed in an incubator adjusted to 2% oxygen for 24 hours, and then preconditioned mouse CDC sheets were implanted into the infarcted heart of old myocardial infarction mouse models. Hypoxic preconditioning of CDC sheets remarkably increased the expression of vascular endothelial growth factor through the PI3-kinase/Akt signaling pathway. Implantation of preconditioned CDC sheets improved left ventricular function inchronically infarcted hearts and reduced fibrosis. The therapeutic efficacy of preconditioned CDC sheets was higher than the CDC sheets that were cultured under normaxia condition. These results suggest that hypoxic preconditioning augments the therapeutic angiogenic and anti-fibrotic activity of CDC sheets. A combination of cell sheets and hypoxic preconditioning offers an attractive therapeutic protocol for CDC transplantation into chronically infarcted hearts.

[Aortic Arch-descending Aorta Bypass for Intraoperative Lower Body Malperfusion during Chronic Type A Aortic Dissection Repair]

We present a case of intraoperative lower body malperfusion in a 55-year-old woman who was undergoing total aortic arch replacement (TAR) for chronic type A aortic dissection. We planned 2-staged operation that consisted of total aortic arch replacement using the elephant trunk technique and thoracic endovascular aneurysm repair. During the 1st surgery, hemodynamic findings after TAR indicated lower body malperfusion, with the blood pressure of the upper body of 127/46 (68) mmHg and that of the lower body of 71/46 (51) mmHg. Transesophageal echocardiography showed narrowing of the true lumen and expansion of the false lumen of the proximal descending aorta. We performed aortic arch-descending aorta bypass using the branch for arterial return of the prosthetic arch graft. After the bypass procedure, lower body malperfusion improved. The postoperative course was uneventful. Extraanatomical aortic arch-descending aorta bypass may be an option for improving intraoperative malperfusion of the lower body due to true lumen narrowing.

[Radical nephrectomy and caval tumor thrombectomy with cardiopulmonary bypass combined with right anterior minithoracotomy;report of a case]

Renal cell carcinoma is a tumor with a distinct feature that it can invade the renal vein and grow intravascularly extending to the inferior vena cava (IVC). We herein report a case of a 71-year-old female who presented with a neoplasm that involved the right kidney and an intra-IVC tumor thrombus. We performed radical nephrectomy and tumor thrombectomy under cardiopulmonary bypass through a right anterior mini thoracotomy. The patient was discharged on the 13th day after the surgery without any complication, and is currently in good health at 7 months after the operation.

Mortality and morbidity after total aortic arch replacement

BACKGROUND

Total aortic arch replacement is associated with considerable mortality and morbidity. Although operative death is the most extreme adverse clinical end point, postoperative morbidity can also be devastating for survivors.

METHODS

We examined the short-term and long-term outcomes of 146 patients who underwent total aortic arch replacements between September 2003 and September 2011.

RESULTS

The overall in-hospital mortality was 4.8%, and major postoperative morbidity during hospitalization occurred in 29 patients (19.9%). Multivariate analyses demonstrated that risk factors for hospital death were left thoracotomy (odds ratio [OR], 51.92; p=0.01), high preoperative serum creatinine values (OR, 3.88; p=0.02), and intraoperative blood loss (OR, 1.01; p=0.04). Ruptured aorta (OR, 7.13; p=0.02) and previous myocardial infarction (OR, 5.13; p=0.04) were identified as independent risk factors for major postoperative morbidity. The postoperative survival of all patients at 5 years was 76.7%±5%. After hospital discharge, the standardized mortality ratios showed no significant difference between hospital survivors and a comparable Japanese population and were 1.09 (p=0.41) among patients without major morbidity and 1.82 (p=0.12) among those with major morbidity. The development of renal failure requiring hemodialysis increased the risk of long-term death (hazard ratio, 5.59; p=0.03), even among hospital survivors.

CONCLUSIONS

Our approach for total arch replacement resulted in low in-hospital mortality and morbidity. Long-term outcomes are stable in hospital survivors, especially in the absence of a postoperative requirement for dialysis.

Pseudoaneurysm of the ascending aorta 31 years after mitral valve replacement

We describe a rare case of an ascending aortic pseudoaneurysm 31 years after mitral valve replacement with a Björk-Shiley mechanical valve. The aneurysm presumably expanded gradually during the years following surgery. As the valve was functioning normally, it was left in situ while the ascending aorta was replaced. This report provides valuable information regarding the long-term nature of this patient's pseudoaneurysm, and the long-term durability of the Björk-Shiley spherical valve in the mitral position.

[Apico-aortic valved conduit for aortic stenosis in patients who could not tolerate median sternotomy]

This report presents 3 cases treated with an apico-aortic valved conduit. Cases 1, 2:A 67-year-old female patient and a 60-year-old male patient what had undergone coronary artery bypass grafting were admitted to our hospital for severe aortic stenosis. Computed tomography showed a severe calcified ascending aorta, and coronary angiography revealed patent bypass graft. Case 3:A 71-year-old male patient that had esophagectomy with retrosternal colonic interposition for esophagus cancer after distal gastrectomy. In addition, he had experienced anterior mediastinal drainagic therapy for anastomotic leak. All 3 patients were treated by implantation of an apico-aortic valved conduit. Operation:This procedure was performed through the 5th intercostal space under a beating heart with cardiopulmonary bypass.

RESULT

Postoperative courses were uneventful. All patients are still alive without procedure-related events.

CONCLUSION

This surgical procedure can be an effective alternative when conventional aortic valve replacement cannot be performed for aortic stenosis patients.

[Video-assisted thoracoscopic implantation of left ventricular pacing lead;usefulness of CARTO system;report of a case]

A 70-year-old man, with a history of broad anterior myocardial infarction and repeated several hospitalizations due to heart failure, was referred to our institution for cardiac resynchronization therapy. However, as intravenous implantation of the left ventricular pacemaker lead was not possible, the patient underwent video-assisted thoracoscopic (VAT) implantation. We noted broad myocardial scarring and patent grafts, along with previously bypassed left internal thoracic artery( LITA)-left anterior descending artery (LAD) and right internal thoracic artery (RITA)-D1;thus, the area suitable for implantation of the left ventricule (LV) pacemaker was believed to be restricted. Therefore, we decided to determine the viable myocardial area by using CARTO system and identify the appropriate access port positions for the subsequent VAT surgery. After the LV pacemaker lead was implanted, the recorded pacing threshold was found to be <1.2 V at 0.5 ms. Thus, the CARTO system might be useful to preoperatively identify an area suitable for surgical implantation of a LV pacemaker lead in patients with ischemic cardiomyopathy.

Predictors of late aortic events after Stanford type B acute aortic dissection

OBJECTIVE

Patients with Stanford type B acute aortic dissection usually receive medical treatment during the acute phase. The present study aimed to elucidate the factors predicting late aortic events in patients treated conservatively for acute type B dissections.

METHODS

From March 1991 to March 2011, 117 patients were enrolled in the present study, with a mean follow-up period of 5.1 ± 4.1 years. The patients were divided into 4 groups according to their false lumen status at onset: group F, fully open (n = 26, 22.2%); group P, partially thrombosed (n = 23, 19.6%); group U, ulcer-like projections (n = 22, 18.9%); and group T, completely thrombosed (n = 46, 39.3%).

RESULTS

Long-term survival did not significantly differ among the groups. The Kaplan-Meier event-free rate curve showed that aortic events occurred less frequently in group T than in the other 3 groups; the 5-year event-free rate was 65.4%, 58.8%, 36.1%, and 95.7% for groups F, P, U, and T, respectively. Cox regression analysis showed that the presence of ulcer-like projections (P = .016) and a maximum aortic diameter of ≥ 40 mm (P = .003) were predictors of late aortic events.

CONCLUSIONS

When patients have a maximum aortic diameter of ≥40 mm or ulcer-like projections at onset, early surgical intervention should be considered to prevent positive remodeling of the aorta.

Transapical extirpation of a left ventricular thrombus in Takotsubo cardiomyopathy

A 58-year-old Japanese female was referred to our hospital. Although the electrocardiogram showed ST elevation, coronary angiography showed intact coronary artery. We diagnosed Takotsubo cardiomyopathy and a left ventricular thrombus. Anticoagulation was administered; however, the left ventricular thrombus had become mobile and protrusive. We extirpated the left ventricular thrombus via trans-apical approach. Left ventricular thrombus is rare in Takotsubo cardiomyopathy, but these patients are at a higher risk of thromboembolism, especially if the thrombi are mobile and protruding.

Ratio of preoperative atrial natriuretic peptide to brain natriuretic peptide predicts the outcome of the maze procedure in mitral valve disease

Background

Although the maze procedure is an established surgical treatment for eliminating atrial fibrillation (AF), its efficacy in patients with mitral valve disease has remained unsatisfactory. A useful predictive marker for the outcome of the maze procedure is needed. The aim of this study was to investigate whether the preoperative ratio of atrial natriuretic peptide (ANP) to brain natriuretic peptide (BNP) reflects atrial fibrosis and can be used to predict the maze procedure outcome in patients with mitral valve disease.

Methods

A total of 23 consecutive patients who underwent the radial approach to the maze procedure combined with mitral valve surgery were included in this study and were divided into a sinus rhythm (SR) group (n=16) and an AF group (n=7) based on postoperative cardiac rhythm. Plasma samples were obtained at rest before the operation and were analysed for ANP and BNP levels. Atrial tissue samples taken during surgery were used to quantify interstitial fibrosis.

Results

The preoperative ANP-to-BNP ratio in the SR group was significantly higher than that in the AF group (0.74 +/− 0.29 vs. 0.42 +/− 0.28, respectively; p=0.025). Receiver operating characteristic (ROC) curve analysis was used to identify factors that predict outcomes after the maze procedure. The area under the ROC curve for the ANP-to-BNP ratio (0.81) was greater than for any other preoperative factors. Moreover, the preoperative ANP-to-BNP ratio demonstrated a negative correlation with left atrial fibrosis (r=−0.69; p=0.003).

Conclusions

The preoperative ANP-to-BNP ratio can predict maze procedure outcome in patients with mitral valve disease, and it represents a potential biomarker for left atrial fibrosis.

Arch translocation and the intra-arch elephant-trunk technique with collared graft for extended chronic dissecting aortic aneurysm

Management of extensive, chronic, dissecting aortic aneurysms after prior repair of the ascending aorta presents a technical challenge for surgeons. A symptomatic 64-year-old patient was admitted for elective surgical repair of an aortic annular dilatation, causing severe aortic regurgitation, and a Crawford type II extended thoracoabdominal aneurysm, 4 years after he underwent primary repair of an acute aortic dissection. The aorta was diffusely dilated, and there were no sites beyond the distal aortic arch where anastomosis could be performed. We successfully performed total aortic replacement with a 2-stage strategy, using an arch translocation technique and an intra-arch elephant-trunk technique.

Important role of the angiotensin II pathway in producing matrix metalloproteinase-9 in human thoracic aortic aneurysms

BACKGROUND

The precise pathologic mechanisms underlying human thoracic aortic aneurysms (TAAs) remain uncertain, except that matrix metalloproteinase-9 (MMP-9) is considered a key enzyme for the degradation of extracellular matrix in aneurysm walls. The aim of this study was to elucidate the significance of the angiotensin II (AngII) pathway to MMP-9 production in human TAA walls.

METHODS AND RESULTS

We examined the activation of Smad2, a common downstream molecule of AngII and transforming growth factor β (TGF-β) pathways, and the expression of MMP-9 in human nonsyndromic TAA walls. We observed significant increases in Smad2 activation and MMP-9 expression, associated with disruption of elastic lamellae. Using human TAA walls in ex vivo culture, we investigated whether AngII and/or TGF-β pathways are essential for MMP-9 production. Unexpectedly, TGF-β receptor inhibitor had no effect on MMP-9 production. We used PD98059, an inhibitor of extracellular signal-regulated kinase (ERK) activation, and demonstrated that PD98059 dramatically reduced MMP-9 production with attenuation of Smad2 activation. Moreover, exogenous AngII resulted in increases in Smad2 activation and MMP-9 production, in an ERK-dependent manner.

CONCLUSION

Our findings indicate that the AngII/ERK pathway has an important role in the production of MMP-9 in human nonsyndromic TAA walls.

Heat shock factor 1 contributes to ischemia-induced angiogenesis by regulating the mobilization and recruitment of bone marrow stem/progenitor cells

Bone marrow (BM)-derived stem/progenitor cells play an important role in ischemia-induced angiogenesis in cardiovascular diseases. Heat shock factor 1 (HSF1) is known to be induced in response to hypoxia and ischemia. We examined whether HSF1 contributes to ischemia-induced angiogenesis through the mobilization and recruitment of BM-derived stem/progenitor cells using HSF1-knockout (KO) mice. After the induction of ischemia, blood flow and microvessel density in the ischemic hindlimb were significantly lower in the HSF1-KO mice than in the wild-type (WT) mice. The mobilization of BM-derived Sca-1- and c-kit-positive cells in peripheral blood after ischemia was significantly lower in the HSF1-KO mice than in the WT mice. BM stem/progenitor cells from HSF1-KO mice showed a significant decrease in their recruitment to ischemic tissue and in migration, adhesion, and survival when compared with WT mice. Blood flow recovery in the ischemic hindlimb significantly decreased in WT mice receiving BM reconstitution with donor cells from HSF1-KO mice. Conversely, blood flow recovery in the ischemic hindlimb significantly increased in HSF1-KO mice receiving BM reconstitution with donor cells from WT mice. These findings suggest that HSF1 contributes to ischemia-induced angiogenesis by regulating the mobilization and recruitment of BM-derived stem/progenitor cells.

[Surgical therapy for ischemic cardiomyopathy]

BACKGROUND

Surgical ventricular restoration (SVR) is considered as an effective surgical procedure for patients with ischemic myocardiopathy( ICM). However" surgical treatment for ischemic heart failure (STICH)" trial concluded that adding SVR to coronary artery bypass grafting (CABG) did not relieve symptoms and failed to lower death rate or cardiac rehospitalization as compared with CABG alone.

AIM

The aim of this study was to investigate the efficacy of CABG with SVR for ICM.

METHODS AND RESULTS

We retrospectively studied 24 patients who had undergone CABG with or with out SVR for ICM from October 1992 to June 2008. In CABG with SVR group, cardiac symptoms were relieved and the left ventricular end-systolic volume index (LVESVI) was reduced from the baseline significantly. However cardiac symptoms were relieved only in CABG-S [left ventricular end-diastolic dimension (LVDd)<60 mm] group, and not in CABG-L (LVDd≥60 mm) group. LVESVI was not reduced in CABG without SVR group.

CONCLUSION

SVR contributed to relieving the symptoms, and improving the left ventricular function and the long-term survival of patients with especially dilated ICM, which could not be achieved by CABG alone.

The effects of mechanical stress on the growth, differentiation, and paracrine factor production of cardiac stem cells

Stem cell therapies have been clinically employed to repair the injured heart, and cardiac stem cells are thought to be one of the most potent stem cell candidates. The beating heart is characterized by dynamic mechanical stresses, which may have a significant impact on stem cell therapy. The purpose of this study is to investigate how mechanical stress affects the growth and differentiation of cardiac stem cells and their release of paracrine factors. In this study, human cardiac stem cells were seeded in a silicon chamber and mechanical stress was then induced by cyclic stretch stimulation (60 cycles/min with 120% elongation). Cells grown in non-stretched silicon chambers were used as controls. Our result revealed that mechanical stretching significantly reduced the total number of surviving cells, decreased Ki-67-positive cells, and increased TUNEL-positive cells in the stretched group 24 hrs after stretching, as compared to the control group. Interestingly, mechanical stretching significantly increased the release of the inflammatory cytokines IL-6 and IL-1β as well as the angiogenic growth factors VEGF and bFGF from the cells in 12 hrs. Furthermore, mechanical stretching significantly reduced the percentage of c-kit-positive stem cells, but increased the expressions of cardiac troponin-I and smooth muscle actin in cells 3 days after stretching. Using a traditional stretching model, we demonstrated that mechanical stress suppressed the growth and proliferation of cardiac stem cells, enhanced their release of inflammatory cytokines and angiogenic factors, and improved their myogenic differentiation. The development of this in vitro approach may help elucidate the complex mechanisms of stem cell therapy for heart failure.

Validation of the JapanSCORE versus the logistic EuroSCORE for predicting operative mortality of cardiovascular surgery in Yamaguchi University Hospital

PURPOSE

Recent studies have shown that the European System for Cardiac Operative Risk Evaluation (Euro-SCORE) is a reliable risk model in cardiac surgery. In Japan, the JapanSCORE has been devised as the Japanese original risk model for cardiovascular surgery. We evaluated the validity of the JapanSCORE, especially in comparison with the logistic EuroSCORE METHODS: We calculated the predicted mortality according to two risk models for 523 consecutive patients who underwent cardiovascular surgery within a 6-year period (July 2003 to June 2009) at Yamaguchi University Hospital. We assessed the scores' validity by calculating the area under the receiver operating characteristics curve (C-index) and by the chi-squared test or Fisher's exact test.

RESULTS

The C-indexes were 0.688 with the logistic EuroSCORE and 0.770 with the JapanSCORE (P = 0.053). Although the difference was not significant, the JapanSCORE tended to be more accurate. The C-indexes limited to isolated coronary artery bypass grafting (CABG) were 0.564 with the logistic EuroSCORE and 0.790 with the JapanSCORE (P = 0.001). The Japan-SCORE was significantly more valid than the logistic EuroSCORE for isolated CABG. The actual mortality was 4.0%; the mean predictive mortality was 5.6% with the JapanSCORE and 15.1% with the logistic Euro-SCORE. The mortality predicted by the JapanSCORE was closer to the observed mortality. There was a significant difference between the observed mortality and the logistic EuroSCORE (P < 0.0001).

CONCLUSION

The JapanSCORE seems to be a more reliable risk model than the logistic EuroSCORE for patients undergoing cardiac or thoracic aortic surgery at Yamaguchi University Hospital.