Daihiko Eguchi

Surgical strategy of abdominal aortic aneurysm with preoperative renal failure

OBJECTIVES To determine the effect of preoperative renal failure on the outcome of patients suffering from infrarenal abdominal aortic aneurysm (AAA). METHOD During the period from January 1979 to August 1995, 364 patients with AAA were admitted to our hospital and 323 underwent elective repair. The patients were retrospectively analysed in three groups. Group I was composed of 273 patients with a normal renal function who underwent an aneurysm repair. Group II was composed of 50 patients who demonstrated a preoperative renal dysfunction (creatinine above 2.0 mg/dl or creatinine clearance below 40 ml/min) and underwent an operation, including three patients maintained on chronic haemodialysis. Group III was composed of 18 patients with a renal dysfunction who did not undergo repair, including one patients maintained on chronic haemodialysis. RESULTS The operative mortality rate of groups I and II were 0.4% and 2.0%, respectively, although no significant difference was observed. The incidence of postoperative cardiac and pulmonary complications were also comparable in two groups. No patients required acute haemodialysis. The 5-year survival rate of group II (44%) was significantly higher than that of group III (20%), and seven of the 18 patients (39%) in group III ultimately died of a rupture of the AAA. CONCLUSIONS Patients with chronic renal failure can undergo an abdominal aortic aneurysm repair based on the same indications as those without renal failure.

Acceleration of impairment of endothelium-dependent responses under poor runoff conditions in canine autogenous vein grafts

OBJECTIVES To assess the effects of changes in shear stress on endothelium-dependent responses. MATERIALS AND METHODS Autologous vein grafts were implanted in poor or normal distal runoff limbs of 10 mongrel dogs. Six weeks after grafting the vein grafts were removed, cut into rings, and suspended in organ chambers for isometric tension recording. RESULTS The average value of intimal thickening was 110.7 +/- 45.2 microns in poor runoff limbs and 65.5 +/- 27.9 microns in control limbs, respectively. There was a significant difference between the two groups. Acetylcholine caused comparable endothelium-independent contractions in both groups. In the control group, adenosine diphosphate, thrombin and A23187 caused endothelium-dependent relaxations. In the poor runoff group, the endothelium-dependent relaxations caused by adenosine diphosphate and thrombin were impaired, while A23187 caused comparable endothelium-dependent relaxations. Direct relaxations in response to sodium nitroprusside were comparable between the two groups. CONCLUSIONS This dysfunction of the endothelium under conditions of abnormal flow may accelerate intimal thickening of the vein graft and result in late graft failure.

The effect of overweight status on the short-term and 20-y outcomes after hepatic resection in patients with hepatocellular carcinoma

BACKGROUND We aimed to evaluate the impact of body mass index (BMI) on the short- and long-term outcomes of hepatic resection in patients with hepatocellular carcinoma (HCC). METHODS We performed 371 hepatic resections in HCC patients whom we categorized into two groups based on BMI: BMI ≥ 25 (n = 77) and BMI <25 (n = 294). We compared surgical outcomes between groups. RESULTS The incidence of postoperative complications in the BMI ≥ 25 group was comparable to those in the BMI <25 group. However, patients in the BMI <25 group showed a significantly worse long-term prognosis than those in the BMI ≥ 25 group (P < 0.01). The results of multivariate analyses showed that BMI <25 was an independent and prognostic indicator of long-term outcome after hepatic resection in HCC patients. CONCLUSIONS A BMI ≥ 25 is not a risk factor for mortality or postoperative complications, and is considered to provide a better long-term prognosis (>20 y) than a BMI <25 in patients with HCC after hepatic resection. Further studies are needed to determine whether these results apply to other patient populations outside Japan where BMI ≥ 30 is more prevalent.

The effect of probucol on intimal thickening of autologous vein grafts in hyperlipidemic rabbit

Probucol is used to treat hypercholesterolemia and also has an anti-atherogenic effect. The effects of probucol on intimal thickening of autologous vein graft in hyperlipidemic rabbits with poor distal run-off were investigated. A poor distal run-off model was prepared in the right hindlimb of 18 rabbits allocated to four groups depending on diet: normolipidemic commercial diet, (NL group, n = 5); hyperlipidemic diet (HL group, n = 5); commercial diet with 1% probucol (NP group, n = 4); and hyperlipidemic diet with 1% probucol (HP group, n = 4). After 4 weeks the femoral vein grafts were implanted into normal (n = 18) or poor (n = 18) runoff limbs. Vein grafts were harvested 4 weeks after implantation. Intimal thickening of the graft was measured and macrophages therein examined immunohistochemically. The serum cholesterol level was not reduced by probucol treatment. The mean flow rate of the graft was significantly reduced in the poor run-off limb. On histological examination intimal thickening in the poor run-off limb was significantly greater than that of controls, while intimal thickening in the HL and HP groups was enhanced compared with that in the NL and NP groups, respectively. Mean intimal thickening in each limb in HP group rabbits was significantly lower than that in HL rabbits (microm): control (HL/HP): 99.4(7.4)/58.8(0.7) (P < 0.05); poor run-off (HL/HP): 155.3(9.6)/130.3(7.3) (P < 0.O5). There was no difference between NL and NP (microm): control (NL/NP): 44.6(24.7)/31.5(12.8); poor run-off (HL/HP): 115.3(13.8)/97.5(34.0). In addition, enhanced intimal thickening due to poor distal run-off was not suppressed. Immunohistochemical staining showed intimal macrophage infiltration in the HL and HP groups; however, macrophage infiltration in grafts in the HP group was less than in the HL group. In conclusion, under hyperlipidemic conditions, probucol decreased intimal thickening enhancement of the vein graft, and suppressed intimal macrophage infiltration. These findings were similar to the anti-atherogenic effect of probucol in the native artery. Hence, probucol administration after vascular reconstruction with vein grafts in patients with hyperlipidemia may be beneficial.

Mechanism of contraction induced by bradykinin in the rabbit saphenous vein

1 By using fura‐PE3 fluorometry and receptor‐coupled permeabilization by α‐toxin, the mechanism of the bradykinin (BK)‐induced contraction was determined in the rabbit saphenous vein (RSV). The receptor subtype responsible for the BK‐induced contraction of RSV was determined by means of a pharmacological blocker study and reverse transcription polymerase chain reaction (RT‐PCR). 2 In the presence of extracellular Ca2+ (1.25 mM), BK (10−11‐3 × 10−7 m) induced increases in both the cytosolic Ca2+ concentration ([Ca2+]i) and force, in a concentration‐dependent manner. Both the release of Ca2+ from the store site and the influx of extracellular Ca2+ contribute to an increase in [Ca2+]i induced by BK. 3 In the absence of extracellular Ca2+, the application of 10−7 M BK induced transient elevations of [Ca2+]i and force, both of which thereafter declined to the levels observed before the application of BK. When extracellular Ca2+ was replenished (1.25 mM), [Ca2+]i and force increased to form a peak, followed by a sustained elevation in the presence of BK. When an RSV strip was pretreated with 10−5 M thapsigargin for 20 min, the BK‐induced transient increases in both [Ca2+]i and force were markedly inhibited. 4 These responses induced by BK were inhibited by Hoe 140 (D‐Arg‐[Hyp3, Thi5, D‐Tic7, Oic8] bradykinin), a highly specific bradykinin B2 receptor antagonist, in a concentration‐dependent manner. In RT‐PCR, B2‐receptor mRNA was expressed in the smooth muscle of RSV. 5 The [Ca2+]i‐force relationships, which were determined by cumulative applications of extracellular Ca2+ (0–5 mM) during 118 mM K+‐depolarization, shifted to the upper left in the presence of BK, thus indicating that BK induced a greater force than 118 mM K+‐depolarization for a given level of [Ca2+]i. 6 In α‐toxin‐permeabilized preparations of RSV, application of 10−7 M BK after a steady state contraction had been induced by a mixture of 5 × 10−7 M Ca2+, 10−6 M GTP and 10−6 M captopril caused an additional force development at a constant [Ca2+]i. However, treatment with 1 mM guanosine‐5′‐O‐(β‐thiodiphosphate) (GDPβS) for 5 min before and during the application of BK (10−7 m), abolished this BK‐induced additional contraction. 7 These results indicated that in RSV: (1) BK elicits vasoconstriction by increasing the Ca2+ influx from the extracellular space, Ca2+ release from intracellular thapsigargin‐sensitive storage sites and increasing the Ca2+ sensitivity of the contractile apparatus, (2) the BK‐induced increase in Ca2+ sensitivity is mediated by G‐protein, (3) the BK‐induced contractions are mediated via B2‐receptors and (4) the smooth muscle cells express B2‐receptor mRNA.

Enhancement of nitric oxide production after arterial reconstruction in patients with arteriosclerosis obliterans.

PURPOSE Nitric oxide (NO) not only relaxes vascular smooth muscles, but it also reduces platelet adhesion and is itself a potent antiaggregatory substance. Experimental studies have shown that the release of NO is modulated by the blood flow. However, little clinical information is available about the effects of hemodynamic changes after arterial reconstruction on NO production. We therefore examined whether the plasma levels of nitrite (NO2-) and nitrate (NO3-) ions increased after arterial reconstruction in patients with arteriosclerosis obliterans (ASO). METHODS Blood samples were obtained from the femoral artery in seven patients who underwent arterial reconstruction and seven healthy individuals (control). NO2- and NO3- levels were measured using high-performance liquid chromatography before the operation and 1 hour and 14 days after the operation. In addition, the mean femoral artery blood flow and ankle-brachial pressure index (ABI) were also measured using a duplex and Doppler velocimeter both before and after the operations. RESULTS In the control subjects, the mean plasma NO2-, NO3-, and NOx (NO2- plus NO3-) levels in the femoral artery were 0.37 +/- 0.15 mumol/L, 45.6 +/- 10.8 mumol/L, and 46.0 +/- 10.9 mumol/L, respectively. Before the operation in the patients with ASO, the mean plasma NO3- (23.8 +/- 2.2 mumol/L) and NOx levels (24.0 +/- 2.3 mumol/L) were significantly lower than those in the control subjects, whereas the plasma NO2- levels (0.27 +/- 0.04 mumol/L) were comparable between the two groups. At 14 days after operation, the mean plasma NO3- and NOx levels in the femoral artery were significantly increased to 42.8 +/- 5.6 mumol/L and 43.4 +/- 5.6 mumol/L compared with those before the operation, whereas the mean plasma NO2- levels (0.50 +/- 0.05 mumol/L) changed significantly. The mean ABI and the mean flow rate before the operation were 0.32 +/- 0.07 and 344 +/- 145 ml/min, respectively. Both the ABI and the mean flow rate significantly increased to 1.04 +/- 0.06 and 627 +/- 141 ml/min after the operation. CONCLUSIONS In patients who have ASO, the mean plasma level of NO is significantly lower than that of healthy individuals. In patients with ASO, the mean blood flow increased significantly after arterial reconstruction. This hemodynamic improvement may thus enhance NO production and may also help to maintain the patency of the bypass graft or native artery.

Comparison of retroperitoneal and transperitoneal approach for reconstruction of abdominal aortic aneurysm in patients with previous laparotomy

Although the standard surgical approach for repair of infrarenal abdominal aortic aneurysm (AAA) has been the transperitoneal approach, several reports have suggested the usefulness of retroperitoneal aortic reconstruction. However, the superiority of the retroperitoneal compared with transperitoneal approach is still controversial. To compare the efficacy of the retroperitoneal with that of the transperitoneal approach in elective AAA resection, 19 consecutive cases with previous laparotomies were randomly reviewed. From January 1990 through December 1992, 94 consecutive patients underwent elective reconstructions of an infrarenal AAA. Among them, 75 patients had had no previous surgery of any kind. In all of them, the transperitoneal approach was used (Group I). Nineteen other patients who had various laparotomies were randomly divided into two groups. The transperitoneal approach was used in 10 patients (Group II), and the retroperitoneal approach was used in 9 patients (Group III). Thus, the patients were separated into three groups and the intra- and postoperative parameters were compared. Surgical data including operative time, intraoperative blood loss, and aortic cross-clamping time did not differ significantly between the transperitoneal approach in the patients without laparotomy (Group I) and the retroperitoneal approach (Group II). In addition, the postoperative recovery including the initiation of alimentation and postoperative hospitalization also did not differ significantly between the two groups. However, there was a significant difference in the operative time and the blood loss between the retroperitoneal approach (Group II) and transperitoneal approach (Group III) in the patients with previous laparotomy. In addition, the postoperative parameters including the initiation of oral intake was sooner and hospitalization was significantly shorter in the retroperitoneal group (Group II) than in the transperitoneal group (Group III) with previous laparotomy. There was no incidence of postoperative adhesive ileus in the patients with the retroperitoneal approach (Group II). The results demonstrated no important advantage for the retroperitoneal approach compared with routine transperitoneal approach in the patients without previous laparotomy. However, in the patients with previous laparotomies, the retroperitoneal approach is a preferable alternative to the transperitoneal route.

Raison d'etre of Tibial Artery Bypass for Intermittent Claudication in the Era of Endovascular Therapy

BACKGROUND There is currently no positive opinion regarding infrapopliteal revascularization for intermittent claudication (IC) in any guidelines. The aim of this study was to analyze the outcomes of infragenicular bypass and verify the adequacy of tibial artery bypass for IC. METHODSANDRESULTS Over a 21-year period, 58 below-knee popliteal artery (BKPOP) bypasses and 35 tibial artery bypasses were performed for IC caused by arteriosclerosis obliterans. Graft patency and major amputation (MA) were examined as primary endpoints and the predictor of each outcome was estimated by multivariate analysis. The primary patency (PP), secondary patency (SP), and freedom from MA (ffMA) rates of a prosthetic/vein graft in all cases at 5 years were 19/68%, 22/86%, and 78/100% (P<0.01 in all). Limited to vein graft cases, PP and SP rates of popliteal/tibial bypass at 5 years were 73/62% (P=0.32) and 92/80% (P=0.22), respectively. In tibial artery bypass with a vein graft, the PP and SP rates of a single saphenous vein/spliced vein graft at 5 years were 71/46% (P=0.11) and 89/61% (P=0.03). A prosthetic graft was a common negative predictor for graft patency and MA by multivariate analysis. CONCLUSIONS Tibial artery bypass is an acceptable treatment option for IC when a single saphenous vein can be harvested as a graft conduit. (Circ J 2016; 80: 1460-1469).

Usefulness of duplex scanning for following prosthetic grafts in above-knee femoropopliteal bypass: A new indicator for identification of failing grafts

To assess the utility of routine duplex surveillance for prosthetic grafts in above-knee femoropopliteal bypass, 33 prosthetic grafts (expanded polytetrafluoroethylene; ePTFE 26, externally supported Dacron graft; EXS 7) were prospectively entered into a surveillance protocol from April 1990 through August 1994. Peak systolic flow velocity (PSFV), measured in two segments (midportion of the graft and host popliteal artery), was performed every 3 months. The mean value at the last point is compared between the patent group (n=28) and the occluded group (n=5). The means ± standard deviation (SD) of PSFV at the midportion of the graft are not significantly different in either group (patent group 36.4±7.0 cm/second, occlusive group 34.9±10.0 cm/second). For PSFV at the host popliteal artery, there is a tendency for the means ± SD of PSFV in the patent group to be superior to those in the occluded group (patent group 39.9±12.0 cm/second, occluded group, 29.6±7.4 cm/second). The mean rate of PSFV at the midgraft to PSFV at the popliteal artery (midgraft-popliteral artery index; MPI) in the occluded group is significantly lower than that of the patent group (patent group 1.2±0.3, occlusive group; 0.8±0.2,p<0.01), whereas all anklebrachial index (ABI) of the occluded group at the last point is higher than 0.85. Measurements of PSFV in two segments and calculation of MPI by using duplex scanning are more reliable in identifying failing prosthetic grafts than is determination of ABI.

Percutaneous cardiopulmonary support in surgery for descending thoracic aortic aneurysms

There is uncertainty regarding the optimal method of intraoperative management of patients with aneurysm of the descending thoracic aorta. Although the percutaneous cardiopulmonary support (PCPS) was developed for use in patients with severe heart failure, it has been applied during the resection of descending thoracic aortic aneurysms in our department since 1993. The purpose of this study was to retrospectively compare conventional axillo-iliac temporary bypass to PCPS in patients undergoing repair of a thoracic aortic aneurysm. We retrospectively reviewed 18 consecutive patients with thoracic aortic aneurysms who underwent repair between January 1989 and March 1995. There were 10 patients who underwent aneurysm resection using axillo-iliac temporary bypass (Group I) and 8 who underwent resection using PCPS (Group II). The clamp time, bypass time, estimated blood loss and transfusion requirement did not differ significantly between the two groups. The operating and anesthesia times in Group II (390±91 minutes and 598.8±26.3 minutes, respectively) were significantly shorter than those in Group I (514±100 minutes and 821.5±32.5 minutes, respectively). The duration of postoperative intubation, intensive care unit (ICU) stay, and postoperative hospitalization were significantly shorter in Group II (1.6±0.9, 5.3±1.0, and 17.6±5.6 days, respectively) than in Group I (5.0±2.4, 2.8±0.3, and 24.3±4.8 days, respectively). Percutaneous cardiopulmonary support is a useful technique in surgery for thoracic aortic aneurysms. The advantages of this technique over conventional axillo-iliac temporary bypass are shortened operative time, duration of intubation, ICU stay, and postoperative hospitalization. In addition, it is easy to maintain the bypass flow using a centrifugal pump, and to maintain the body temperature using a heating exchanger.