Masahiro Aizaki

Screening for abdominal aortic aneurysm and occlusive peripheral vascular disease in Japanese residents

To evaluate the prevalence of abdominal aortic aneurysm (AAA) and occlusive peripheral vascular disease (PVD) in Japanese residents, and to examine the correlations between these diseases and the risk factors of atherosclerosis, 348 residents of a village in central Japan aged between 60 and 79 years were screened. The screening for AAA was performed using ultrasonography (US) and that for PVD was performed by palpation and Doppler US. No AAA was found, and a right common iliac arterial aneurysm was detected in a 79-year-old man (0.3%). The mean diameter of the infrarenal abdominal aorta was 18.7 mm and an abdominal aorta of 25 mm or greater in diameter was seen in 16 participants (4.6%), all of whom need to be followed up. PVD was suspected in two patients (0.6%) with a low ankle brachial pressure index. Of a total of five patients diagnosed or suspected of having a common iliac arterial aneurysm or PVD, four (80%) had at least one risk factor for atherosclerosis. Thus, we conclude that Japanese residents with risk factors predisposing them to atherosclerosis such as hypertension, obesity, abnormal serum lipid levels, and a history of smoking should be selectively screened for AAA and PVD due to the low prevalence of these diseases and from the viewpoint of cost-effectiveness.

The optimal pressure for initial flush with UW solution in heart procurement

OBJECTIVE University of Wisconsin (UW) solution is widely used in organ preservation. Some investigators have reported that high pressure during initial flush with UW solution may induce vasoconstriction and endothelial damage, because of its high potassium content and high viscosity. However, using lower pressure during the initial flush may lead to irregular distribution of the solution and incomplete flushing of blood components from coronary vascular beds. This experimental study evaluated the effects of a range of initial flush pressures during heart procurement, followed by orthotopic transplantation of the graft after 12 hours of preservation. MATERIALS AND METHODS Twelve pairs of adult mongrel dogs, weighing 9 to 14 kg, formed the recipient-donor combinations. After determining hemodynamic status by measuring cardiac output, left ventricular pressure (LVP), and maximum positive and negative change in LVP (+/-LVdP/dt), donor hearts were excised. Coronary vascular beds were flushed with 4 degrees C UW solution at a pressure of 60 mm Hg in the low-pressure group (n = 6) and at 120 mm Hg in the high-pressure group (n = 6). After 12 hours of cold preservation, orthotopic transplantation was performed using cardiopulmonary bypass (CPB). The hemodynamics of the transplanted graft were assessed by comparing recovery rates (%) from donor hearts 2 hours after weaning from CPB. Endothelin-1 (ET-1) levels were measured in the blood obtained from the coronary sinus 30 minutes after reperfusion. The transplanted grafts were then harvested for histologic study and measurement of adenosine triphosphate (ATP) content. RESULTS Cardiac output, LVP, LVdP/dt and myocardial tissue ATP content were significantly better (p < 0.05) in the high-pressure group than in the low-pressure group. We found no significant differences in ET-1 levels between the groups. Transmission electron microscopic findings revealed that degeneration of the mitochondria was less extensive in the high-pressure group than in the low-pressure group. We observed no obvious ultrastructural damage to the endothelial cells in either group. CONCLUSION When using UW solution in heart procurement, high pressure is better to completely wash out the blood components and distribute the solution.

The effect of coronary perfusion with an oxygenated celsior solution on 12-hour cardiac preservation

Celsior is a new extracellular-type cardiac preservation solution. We recently developed an apparatus for preservation using low-pressure continuous coronary perfusion. The purpose of this study was to investigate the efficacy of coronary perfusion with an oxygenated Celsior solution using the new apparatus for prolonged cardiac preservation. Adult mongrel dogs weighing 9–13 kg were divided into two groups: the coronary perfusion group (CP; n=5) and the simple immersion group (SI; n=7). The coronary vascular beds were washed out with a 4°C Celsior solution following cardiac arrest using the same solution, and their hearts were excised. In the CP group, the graft was immersed in a 4°C Celsior solution and perfused with the same oxygenated solution. In the SI group, the graft was simply immersed in a 4°C Celsior solution. β-adenosine triphosphate (β-ATP), phosphocreatine (Pcr), inorganic phosphate (Pi) levels and myocardial pH (pHi) were measured immediately after excising the heart, and at 3, 6, and 12 hours after preservation. β-ATP, Pcr, and Pi values were expressed as a percentage of control values, which were measured immediately after excising the heart. β-ATP/Pi and Pcr/Pi levels were significantly higher in the CP group than in the SI group at 6 and at 12 hours after preservation. The pHi levels during preservation were significantly higher in the CP group than in the SI group. Low-pressure hypothermic coronary perfusion with an oxygenated Celsior solution is effective for long-term heart preservation.