Hidekazu Hirai

Risk Factor Analysis in Patients With Liver Cirrhosis Undergoing Cardiovascular Operations

BACKGROUND Variable outcomes of cardiac operations have been reported in cirrhotic patients, but no definitive predictive prognostic factors have been established. This retrospective study assessed operative results to identify risk factors associated with morbidity after cardiovascular operations in cirrhotic patients. METHODS The study comprised 42 cirrhotic patients who underwent cardiovascular operations from January 1991 to January 2009. Thirty patients were Child-Turcotte-Pugh class A, and 12 were class B. Hospital morbidity occurred in 13 patients (31.0%; M group), including 4 who died in-hospital. Patients without severe complications (N group) were compared with the M group patients. The Model for End-Stage Liver Disease (MELD) score was evaluated in 25 patients. RESULTS Significant differences in hospital morbidity between the M vs N groups were identified for platelet count (8.7 +/- 3.8 vs 12.1 +/- 4.2 x 10(4)/microL), MELD score (17.8 +/- 5.3 vs 9.8 +/- 4.9), operation time (370 +/- 88 vs 313 +/- 94 minutes), and cardiopulmonary bypass time (174 +/- 46 vs 149 +/- 53 minutes) in univariate analyses (p < 0.005). Platelet count, operation time, and age were significantly associated with hospital morbidity in multivariate analyses (p < 0.005). Platelet count of 9.6 x 10(4)/microL and MELD score of 13 were cutoff values for hospital morbidity. CONCLUSIONS Careful consideration of operative indications and methods are necessary in cirrhotic patients with low platelet counts or high MELD scores. A high incidence of hospital morbidity is predicted in patients with platelet counts of less than 9.6 x 10(4)/microL or MELD scores exceeding 13.

Therapeutic Potential of Unrestricted Somatic Stem Cells Isolated from Placental Cord Blood for Cardiac Repair Post Myocardial Infarction

Objective—Unrestricted somatic stem cells (USSCs) were successfully identified from human cord blood. However, the efficacy of USSC transplantation for improving left ventricular (LV) function post myocardial infarction (MI) is still controversial. Methods and Results—PBS, 1×106 human fibroblasts (Fbr), 1×105 USSCs (LD), or 1×106 USSCs (HD) were transplanted intramyocardially 20 minutes after ligating the LAD of nude rats. Echocardiography and a microtip conductance catheter at day 28 revealed a dose-dependent improvement of LV function after USSC transplantation. Necropsy examination revealed dose-dependent augmentation of capillary density and inhibition of LV fibrosis. Dual-label immunohistochemistry for cardiac troponin-I and human nuclear antigen (HNA) demonstrated that human cardiomyocytes (CMCs) were dose-dependently generated in ischemic myocardium 28 days after USSC transplantation. Similarly, dual-label immunostaining for smooth muscle actin and class I human leukocyte antigen or that for von Willebrand factor and HNA also revealed a dose-dependent vasculogenesis after USSC transplantation. RT-PCR indicated that expression of human-specific genes of CMCs, smooth muscle cells, and endothelial cell markers in infarcted myocardium were significantly augmented in USSC-treated animals compared with control groups. Conclusions—USSC transplantation leads to functional improvement and recovery from MI and exhibits a significant and dose-dependent potential for concurrent cardiomyogenesis and vasculogenesis.

Synchrotron Radiation Coronary Microangiography for Morphometric and Physiological Evaluation of Myocardial Neovascularization Induced by Endothelial Progenitor Cell Transplantation

Background—Therapeutic effect of stem cell transplantation (SCTx) for myocardial neovascularization has been evaluated by histological capillary density in small animals. However, it has been technically difficult to obtain imaging evidence of collateral formation by conventional angiography. Methods and Results—Peripheral blood CD34+ and CD34− cells were isolated from patients with critical limb ischemia. PBS, CD34− cells, or CD34+ cells were intramyocardially transplanted after ligating LAD of nude rats. Coronary angiography of ex vivo beating hearts 5 and 28 days after the treatment was performed using the third generation synchrotron radiation microangiography (SRM), which has potential to visualize vessels as small as 20 &mgr;m in diameter. The SRM was performed pre and post sodium nitroprusside (SNP) to examine vascular physiology at each time point. Diameter of most collateral vessels was 20 to 120 &mgr;m, apparently invisible size in conventional angiography. Rentrop scores at day 28 pre and post SNP were significantly greater in CD34+ cell group than other groups (P<0.01). To quantify the extent of collateral formation, angiographic microvessel density (AMVD) in the occluded LAD area was analyzed. AMVD on day 28 post SNP, not pre SNP, was significantly augmented in CD34+ cell group than other groups (P<0.05). AMVD post SNP closely correlated with histological capillary density (R=0.82, P<0.0001). Conclusions—The SRM, capable of visualizing microvessels, may be useful for morphometric and physiological evaluation of coronary collateral formation by SCTx. The novel imaging system may be an essential tool in future preclinical/translational research of stem cell biology.

Relation of Aortic Arch Complex Plaques to Risk of Cerebral Infarction in Patients With Aortic Stenosis

Aortic stenosis (AS) and systemic atherosclerosis have been shown to be closely related. We evaluated the prevalence of aortic arch plaques and their possible association with the risk of cerebral infarction in patients with severe AS. Transesophageal echocardiography was performed in 116 patients with severe AS (55 men, mean age 71 ± 7 years, mean aortic valve area 0.68 ± 0.15 cm(2)) who were scheduled for aortic valve replacement. The presence, thickness, and morphology of the aortic arch plaques were evaluated using transesophageal echocardiography. Cerebral infarcts (chronic cerebral infarction and cerebral infarction after cardiac catheterization and aortic valve replacement) were assessed in all patients. Compared to age- and gender-matched control subjects, the patients with severe AS had a significantly greater prevalence of aortic arch plaques (74% vs 41%; p <0.0001) and complex arch plaques such as large plaques (≥4 mm), ulcerated plaques, or mobile plaques (30% vs 10%; p = 0.004). Multivariate logistic analyses showed that the presence of complex arch plaques was independently associated with cerebral infarction in patients with AS after adjusting for traditional atherosclerotic risk factors and coronary artery disease (odds ratio 8.46, 95% confidence interval 2.38 to 30.12; p = 0.001). In conclusion, the results from the present study showed that there is a greater prevalence of aortic arch plaques in patients with AS and that the presence of complex plaques is independently associated with cerebral infarction in these patients. Therefore, the identification of complex arch plaques using transesophageal echocardiography is important for risk stratification of cerebrovascular events in patients with severe AS.

Impact of Valve Prosthesis-Patient Mismatch on Long-Term Survival and Left Ventricular Mass Regression After Aortic Valve Replacement for Aortic Stenosis

Abstract  Background and Aim of the Study: The influence of prosthesis‐patient mismatch on long‐term results after aortic valve replacement remains controversial. The aim of this study was to evaluate the effect of prosthesis‐patient mismatch on survival and the extent of left ventricular mass regression after aortic valve replacement for aortic stenosis. Methods: We retrospectively reviewed 146 patients who underwent isolated aortic valve replacement for aortic stenosis between 1990 and 2005. Prosthesis‐patient mismatch was defined as an effective orifice area/body surface area ≤0.85 cm2/m2. Mean follow‐up was 4.5 ± 3.3 years, with a total follow‐up of 650.0 patient‐years. In 108 patients, follow‐up echocardiography was performed at least 6 months after surgery, and the extent of postoperative left ventricular mass regression was analyzed according to the presence of prosthesis‐patient mismatch. Results: Ten years after surgery, there was no significant difference between patients with mismatch and those without mismatch in overall survival (p = 0.345), actuarial freedom from cardiac‐related death (p = 0.576), and freedom from any valve‐related mortality or morbidity (p = 0.614). Using multivariate analysis, PPM was not a predictor of late cardiac‐related death or all deaths. Echocardiographic examination showed that left ventricular wall thickness and left ventricular mass was significantly decreased postoperatively in both groups. However, the absolute and relative left ventricular mass regression was significantly lower in patients with mismatch than in those without mismatch. Conclusions: This study showed no negative effects of prosthesis‐patient mismatch on survival at 10 years after aortic valve replacement for aortic stenosis. However, the extent of left ventricular mass regression was significantly lower in patients with mismatch.

Rectus abdominis myocutaneous flap after unsuccessful delayed sternal closure

Open chest management is one of the best options for severely impaired hearts after open-heart surgery. Reapproximation of sternal edges compresses the heart, so a less compressive method of chest wall reconstruction should be considered when sternal closure must be delayed. We applied a rectus abdominis myocutaneous flap approach in 3 patients after difficulties with delayed sternal closures. Two patients were weaned off intraaortic balloon pumping and survived without respiratory troubles or wound complications. This alternative method of chest reconstruction is useful in patients after an unsuccessful delayed sternal closure.

Evaluation of risk factors for hospital mortality and current treatment for poststernotomy mediastinitis.

PurposePoststernotomy mediastinitis (PSM) following cardiovascular surgery remains an intractable complication associated with considerable mortality. It is therefore necessary to assess the risk factors associated with hospital mortality and evaluate the surgical treatment options for PSM.MethodsWe identified 59 (2.2%) patients who developed PSM after cardiovascular surgery between January 1991 and January 2010. PSM was defined as deep sternal wound infection requiring surgical treatment. In all, 31 patients were infected with methicillin-resistant Staphylococcus aureus (MRSA); and 14 patients died in hospital from PSM. A total of 51 patients were treated by simple closure or tissue flap reconstruction after débridement (traditional treatment), and 8 underwent closure or reconstruction after negative-pressure wound therapy (NPWT). The risk factors for in-hospital mortality due to PSM were analyzed by comparing the characteristics of survivors and nonsurvivors. The available surgical treatments for mediastinitis were also assessed.ResultsUnivariate analysis identified age, sex, pulmonary disease, MRSA infection, prolonged mechanical ventilation and prolonged intensive care unit stay as risk factors for in-hospital mortality (P < 0.05). Multiple logistic regression analysis identified MRSA infection (odds ratio 20.263, 95% confidence interval 1.580–259.814; P = 0.0208) as an independent risk factor for hospital mortality. NPWT was associated with significantly less surgical failure than traditional treatment (P = 0.0204). There were no deaths as a result of PSM in patients who underwent NPWT irrespective of the presence of MRSA infection.ConclusionMRSA infection was an independent risk factor for PSM-related in-hospital mortality. NPWT may improve the prognosis for patients with MRSA mediastinitis.

Platypnea-orthodeoxia diagnosed by sitting transesophageal echocardiography.

Platypnea-orthodeoxia is a rare syndrome presenting with dyspnea and cyanosis induced by an upright position and relieved by recumbency. We report a patient with an excessively enlarged aortic root who had critical hypoxia due to a paradoxical shunt through the patent foramen ovale only when seated. The postural changes of the shunt, caused by changes in posture, were dynamically detected by transesophageal Doppler echocardiography. We believe that this syndrome should be considered when patients with aortic root dilatation present with inexplicable hypoxia, and that transesophageal Doppler echocardiography in the sitting position can be useful for detecting platypnea-orthodeoxia syndrome.

Cardiotomy suction, but not open venous reservoirs, activates coagulofibrinolysis in coronary artery surgery

OBJECTIVES Closed and miniaturized cardiopulmonary bypass circuits, which eliminate cardiotomy suction and open venous reservoirs with a reduced priming volume, have been reported to be advantageous. We comparatively examined the respective contribution of cardiotomy suction and open venous reservoirs to perioperative activation in coagulofibrinolysis and inflammation systems, with identical conditions of priming volume and anticoagulation. METHODS A total of 75 consecutive coronary artery bypass grafting procedures were performed using 1 of the following 3 cardiopulmonary bypass circuits under identical conditions of priming volumes, heparin coating, and protocols of anticoagulation and transfusion, as follows: a circuit with an open venous reservoir and cardiotomy suction (open group, n = 25), a circuit with an open venous reservoir without cardiotomy suction (nonsuction group, n = 25), or a circuit without either (closed group, n = 25). Blood samples were collected at 8 points up to the first postoperative morning. RESULTS The thrombin-antithrombin III complex, fibrinogen degeneration products, D-dimer, plasmin-α2 plasmin inhibitor complex, and plasminogen activator inhibitor-1 levels were significantly greater in the open group than those in the other 2 groups (P < .0001, for all markers). The C3a and interleukin-6 levels were similar among all the groups. The incidences of perioperative transfusion and postoperative bleeding were increased and the early graft patency rate of saphenous veins was lower in the open group than those in the other 2 groups. CONCLUSIONS Cardiotomy suction, but not open venous reservoirs, causes perioperative coagulofibrinolysis activation, although neither affects the inflammation system. The use of cardiotomy suction needs to be examined further in association with postoperative PAI-1 elevation and early vein graft occlusion.

Outcome After the Modified Bentall Technique With a Long Interposed Graft to the Left Coronary Artery

BACKGROUND The modified Bentall technique, which was reported by Svensson in 1992, is an aortic root composite valve graft replacement involving reimplantation of the left coronary ostium with a long interposed graft wrapping behind the composite graft. The technique is technically advantageous, particularly for complicated or redo aortic roots. To justify the technique, the midterm outcome needs to be evaluated. METHODS Since 1992, 40 patients (4 with Marfan syndrome) underwent the modified Bentall technique (Svenssons modification). The mean age was 54.7 +/- 13.6 years, and 32 patients (80.0%) were male. All hospital survivors have been consecutively followed with annual echocardiographic evaluations. Furthermore, in 2007, multislice computed tomography was performed at 4.7 +/- 3.5 years (maximum, 14.9 years) postoperatively in 30 patients who had preserved renal function. RESULTS No patients have experienced any complications regarding the technique at the follow-up of 5.7 +/- 4.0 years (maximum, 14.9 years), although there were 2 hospital deaths of emergency cases and 5 late deaths owing to noncardiac causes. In 35 patients (92.1% of hospital survivors), no structural complications were detected by multislice computed tomographies of the 30 patients or coronary angiograms of the remaining 5 patients. The consecutive echocardiographic follow-ups showed well-preserved left ventricular function with the most recent ejection fraction being 0.581 +/- 0.078. CONCLUSIONS This Svenssons modification technique was associated with favorable midterm outcomes by multislice computed tomography and consecutive echocardiographic evaluations, indicating long-lasting advantages as well as technical benefits. Thus, the technique can be considered as a helpful and justifiable alternative method.