Kazuhiko Hanzawa

Association between paroxysmal atrial fibrillation and the left atrial appendage ejection fraction during sinus rhythm in the acute stage of stroke: a transesophageal echocardiographic study.

BACKGROUND This study aimed to investigate whether left atrial appendage (LAA) dysfunction evaluated by transesophageal echocardiography (TEE) during sinus rhythm is predictable of paroxysmal atrial fibrillation (PAF) as an embolic source in the acute stage of stroke. METHODS AND RESULTS We measured and analyzed LAA flow velocity (LAA-FV) and LAA ejection fraction (LAA-EF) in 300 acute ischemic stroke patients by TEE. We divided the acute ischemic stroke patients into 3 groups. The atrial fibrillation (AF) group (n=58) comprised patients whose TEE was performed during AF rhythm. The PAF group (n=42) comprised patients with a history of AF but with normal sinus rhythm when TEE was performed. The normal sinus (sinus) group (n=200) did not have any history of AF. We found that mean LAA-FV and LAA-EF values in the PAF group were significantly lower than those in the sinus group (P<.001). The diagnostic accuracy of LAA-FV for the diagnosis of PAF calculated as the area under receiver operating characteristic curves was low (.582, 95% confidence interval [CI]=.498-.665) but that of LAA-EF was modest (.721, 95% CI=.653-.789), with an optimal cutoff point of 49.1%. CONCLUSIONS LAA dysfunction as determined by TEE (LAA-EF<49.1%) in the acute stage of stroke is predictive of PAF with moderate accuracy. Long-term electrocardiographic monitoring is recommended for cryptogenic stroke patients with LAA dysfunction.

“Tail Sign” Associated With Microembolic Signals

BACKGROUND AND PURPOSE Transcranial Doppler ultrasound (TCD) can detect circulating microembolic signals (MES). We focused our attention on tail signs (TS), a signal associated with MES that appeared as a small reversal signal after MES on the high time resolution spectral display. We examined MES and artifacts in an animal study to determine whether TS were specific changes associated with MES and investigated the characteristics of TS in both animal and clinical studies. METHODS In an animal study, adult pigs with venoarterial extracorporeal membrane oxygenation and minimal anticoagulation therapy were used as a model for cerebral embolism. After performing TCD monitoring with a multigated approach, we did an offline analysis to investigate several parameters concerning MES and TS. We also examined TS in patients in a clinical study. RESULTS From a total of 362 MES investigated in the animal study, 72.9% were followed by TS. We could not find any TS associated with artifacts. The time delay between TS and MES was negatively correlated with the velocity of MES. MES almost always appeared first in the proximal channel, whereas TS conversely appeared first in the distal channel. In the clinical study, we were also able to observe TS associated with MES. CONCLUSIONS TS may represent emboli passing down a branch vessel or twisted downstream vessel. TS are specific for MES and can be used as another criterion for MES identification.

The effect of fibrin glue on inhibition of pericardial adhesions

The effect of fibrin glue on inhibition of pericardial adhesions was tested using 26 beagle dogs. Dacron patches were sutured to the heart and tincture of iodine was applied to promote adhesions. Fibrin glue (3 ml) was sprayed over the patches in 15 dogs (test group), and was not separated in the remaining 11 dogs (control group). All animals in the test group had minimal adhesions between the pericardium and the epicardium or patched region, and an accumulation of gelatinous material was found in the subpericardial space. Marked fibrosis and a poor demarcation of the subpericardial space were found in the control group. The adhesion score and the visibility of coronary anatomy in the test group were significantly better than in the control group. The tension strength in the test group was significantly less than in the control group. We concluded, therefore, that fibrin glue may also be useful as an adhesion inhibitor.

Deep venous thrombosis among disaster shelter inhabitants following the March 2011 earthquake and tsunami in Japan: a descriptive study

Objectives A retrospective analysis of data collected during subject screening following Japans March 2011 earthquake and tsunami was performed. We aimed to determine the incidence of deep venous thrombosis (DVT) among screened subjects and to identify risk factors associated with the development of DVT as independent variables. Methods Calf ultrasonography was undertaken in 269 subjects living in 21 shelters in Miyagi prefecture during the one-month period immediately following the March 2011 disaster. Information regarding the health and risk factors of subjects was collected by questionnaire and assessment of physical signs. Results Of the 269 evacuees screened, 65 (24%) met the criteria for calf DVT. We found lower limb trauma, reduced frequency of urination and sleeping in a vehicle to be independent positive predictors of DVT. Conclusions Evacuees had an increased risk of developing DVT, associated with tsunami-related lower limb injury, immobility and dehydration.

One-Year Overview of Deep Vein Thrombosis Prevalence in the Ishinomaki Area Since the Great East Japan Earthquake

After the Great East-Japan Earthquake, the prevalence of deep vein thrombosis (DVT) in disaster shelters in Ishinomaki (Pacific coast, Miyagi, Japan) was found much higher than that ever reported in Japan. In Ishinomaki, twelve patients were found to have pulmonary thromboembolism for one month since the earthquake and DVT was found in 10 of those patients. The calf DVT was examined using ultrasonography in the shelters (from March to July 2011) and in temporary emergency housings (from August to December 2011). Calf DVT was found in 190 of 701 evacuees. DVT prevalence was higher in the tsunami-flooded shelters (34.2%) than in that in the non-flooded shelters (19.1%). This indicated that deteriorated and crowded condition in the tsunami-flooded shelters might induce thrombogenesis in calf veins. Therefore, evacuees were recommended to leave tsunami-flooded areas. DVT prevalence in the shelters was gradually reduced, however, that was still higher in the temporary emergency housings (8.9%) than in the non-disaster area in Japan (2.2% in Yokohama city). The risk of calf DVT in the temporary emergency housings was increased because of reduced blood flow in the calf veins caused by immobility. The residents of the housings were required to be physically active to avoid calf DVT. (English translation of Jpn J Phlebol 2013; 24: 380-384).

Floating thrombus originating from an almost normal thoracic aorta

We present a case of floating thrombus originating from an almost normal thoracic aorta in a 54-year-old man who presented with acute arterial occlusion of his left leg. Transesophageal echocardiography (TEE), computed tomography, and magnetic resonance imaging showed two masses in an almost normal aorta after embolectomy for the acute arterial occlusion. Although the embolus was thrombus histologically, malignant tumors could not be ruled out. The masses did not decrease in size after 7 days of anticoagulant therapy, so they were extirpated under cardiopulmonary bypass (CPB) and TEE guidance. Frozen section examination during CPB indicated that there was no evidence of malignancy in the removed mass. TEE played an important role in the diagnosis and surgery of this condition, and it was useful when deciding on a surgical strategy. Because the treatment strategy for this disease remains controversial, further studies are needed.

Left Atrial ball thrombi without mitral valve disease treated by surgical removal

We describe two patients with free-floating left atrial ball thrombi with no evidence of cardiac disease except atrial fibrillation. One patient had experienced an embolic stroke, and the second patient had a history of stroke and peripheral thromboembolism. In each patient, the thrombi, which were not visible on transthoracic echocardiography, were detected by transesophageal echocardiography. Each patient underwent successful surgical removal using cardiopulmonary bypass.

Occurrence of Deep Vein Thrombosis among Hospitalized Non-Surgical Japanese Patients.

OBJECTIVE To estimate the frequency of deep vein thrombosis (DVT) among non-surgical inpatients, and to evaluate the D-dimer assay as a screening tool for DVT. METHODS Subjects were non-surgical inpatients aged 20 years or older who had been bedridden for at least 24 hours and had moderate-to-high risk factors for DVT. We assessed the presence of DVT by venous ultrasonography. Patients who received a diagnosis of venous thromboembolism (VTE) before admission, who had symptoms or findings of VTE at admission, or who had surgery or trauma within the past 3 months before admission were excluded. RESULTS DVT was confirmed in 96 of 525 patients (18.3%). In a logistic regression analysis, longer duration of hospitalization, higher D-dimer value, and history of cancer surgery were significantly associated with the occurrence of DVT. The D-dimer assay showed high sensitivity (96.1%) and high negative predictive value (97.6%). CONCLUSION Non-surgical inpatients with a long-term hospitalization or history of cancer surgery have a risk for DVT, and need to be considered for added DVT preventive measures as recommended in the prevention guidelines. In addition, the D-dimer assay is beneficial for the screening of DVT in medical practice.

Frequency analysis of high-intensity transient signals of transcranial Doppler ultrasound in patients supported with a left ventricular assist device

Left ventricular assist devices (LVADs) have become more important than ever for patients with terminal heart disease. The chronic shortage of donors for heart transplantation may enhance the importance of LVADs as destination therapy. To prevent cerebral complications, the evaluation of high-intensity transient signals (HITS) of transcranial Doppler (TCD) ultrasound is important. In the present study, HITS were measured on seven occasions in patients supported with LVADs. The high-frequency counts in HITS were greater than the low-frequency counts (47 ± 42 vs. 9 ± 9 in 3 min, P = 0.025), and declined further with oxygen delivery to the patient. The high frequency of signals may imply air microemboli, and the counts may increase with time.

Direct cardiac potential trigger for chronic control of a ventricular assist device.

As a new trigger method for chronic drive control of a ventricular assist device (VAD), a direct cardiac potential trigger was assessed under various conditions in a chronic experimental model. A pneumatic pulsatile VAD was implanted as circulatory support between the left ventricular apex and the ascending aorta in 12 adult pigs. Hemodynamic parameters and pump output were continuously monitored. Two tips of a bipolar electrode were set on the RV anterior wall and the LV posterior wall for recording direct cardiac potential. Counterpulsation drive of the VAD was applied by using the R wave in a standard electrocardiogram (ECG) or the direct cardiac potential as an ECG trigger. As special conditions, various artifacts on ECG, electromusculogram, arrhythmia, irregular ventilation, and passive vibration (simulation of exercise) were set for assessing the ECG trigger modes. Artifacts of irregular ventilation and passive vibration made the drive control poor using a standard ECG trigger. In contrast, the direct cardiac potential trigger maintained the counterpulsation control of the VAD well in all conditions of this study, and was a safe and reliable support for the native heart. It also supported animals for up to 48 hours after operation. The above results suggested that the direct cardiac potential trigger might be useful for monitoring native heart beats and adjusting the support cycle to the native heart cycle as a chronic control method for various VADs.