Surgical treatment of a patient with idiopathic portal hypertension and hepatic encephalopathy

Idiopathic portal hypertension is clinically characterized by splenomegaly and portal hypertension. Hepatic encephalopathy is rare in cases with idiopathic portal hypertension. In a 59-year-old man with recurrent hepatic encephalopathy for one year, a large splenorenal shunt was detected in the computed tomography and angiography, and liver biopsy revealed a portal fibrosis consistent with idiopathic portal hypertension. Devascularization of the upper stomach, splenectomy and closure of the splenorenal shunt were done. The patient has had no experience of encephalopathy since the operation even without drug treatment. Surgery should be considered for treatment of chronic hepatic encephalopathy in patients with idiopathic portal hypertension and portosystemic shunts.

An aneurysm of the right gastroepiploic artery

A palpable mass was unexpectedly found in the upper abdomen of a 67-year-old woman. Computed tomography (CT) and abdominal angiography both indicated an aneurysm of the right gastroepiploic artery. An aneurysmectomy was performed, and the aneurysm was found to be spherical with a diameter of 7.5 x 7.7 cm. The patient was eventually discharged in good condition. The histological findings of the aneurysmal wall revealed medial fibrosis and atherosclerosis. Gastroepiploic artery aneurysms are rare among splanchnic artery aneurysms and most such aneurysms are found to be ruptured. The present report described a quite rare case of an asymptomatic giant gastroepiploic artery aneurysm and also includes a review of the 10 reported cases of gastroepiploic artery aneurysms in the English literature to date. Since gastroepiploic artery aneurysms have a high risk of rupture it is essential that appropriate surgical measures be taken immediately.

Anterior chest wall axillary artery to contralateral axillary vein graft for vascular access in hemodialysis

Patients with end-stage renal failure and peripheral vascular disease pose a difficult management problem in establishing long-term angioaccess for hemodialysis. In 4 patients with access problems, we created axillary artery to contralateral axillary vein Goretex grafts. The grafts were cannulated regularly for periods ranging from 29 to 66 months without difficulty. There was one episode of thrombosis and one of congestive heart failure. The mean venous pressure was 120 mm Hg with a mean arterial flow of 220 ml/min. This type of vascular access can provide adequate blood flow in difficult patients and maintain efficient dialysis. It should be a useful addition to the armamentarium of the vascular surgeon.

Isotopic study of the effects of platelets on development of intimal thickening in autologous vein grafts in dogs

The effects of platelets on the development of intimal thickening of arterially transplanted autologous vein grafts was investigated using canine poor run-off models. A new apparatus consisting of a shielding lead block to measure in vivo platelet adherence only on the intima of the vein graft was developed. In 23 dogs, 51Cr-labelled platelets (20 microCi/kg) were injected and isotope emission over the grafts was counted. Platelet adherence was expressed as the thrombocyte accumulation index (TAI), i.e. the ratio of counts over the graft under an abnormal flow condition in the poor run-off model to those over the graft under normal flow conditions of the contralateral leg. The TAI of the total graft (TTAI) was significantly high immediately and on the first and third days after implantation. The TAIs of the proximal (PTAI) and distal (DTAI) portions of the vein graft were also high at these same times. At 7, 10, 14 and 21 days, the TAI was almost equal to 1.0, a time at which endothelial regeneration was complete as confirmed by scanning electron microscopy. Thus, the prominent intimal thickening of arterially transplanted autologous vein grafts in dogs, induced under an abnormal flow condition, correlates well with the enhanced platelet adherence on the intima of the vein grafts in an early period after implantation.

Ultrastructural evidence of the effects of shear stress variation on intimal thickening in dogs with arterially transplanted autologous vein grafts

Based on our findings that changes in wall shear stress, not the rate of blood flow, were the main hemodynamic factor related to intimal hyperplasia of autologous vein grafts, we further investigated the effect of wall shear stress variation on sequential ultrastructural changes in the intimal hyperplasia of arterially transplanted autovein grafts, using canine models. As noted, wall shear stress variation (tau-variation) could be defined by the variation in wall shear stress within a cardiac cycle, using a desktop flow waveform analyzer. In Group I, which had a high flow rate of 78.4 +/- 4.6 ml/min and low tau-variation of 36.1 +/- 2.2 dynes/cm2, intimal hyperplasia was significant. Ultrastructurally, there was a marked transformation of intimal smooth muscle cells to secretory cells 2 to 4 weeks after implantation. The surface of the intima was lined with modified smooth muscle cells at 2 weeks after implantation. In Group II, which had a low flow rate of 5.6 +/- 2.2 ml/min and normal tau-variation value (174.6 +/- 13.0 dynes/cm2), intimal hyperplasia was minimal, and there were several layers of contractile type smooth muscle cells, with characteristic myofibrillae. The surface of the intima was lined with endothelial cells at 2 weeks after implantation. These findings suggest that, in regions of low wall shear stress variation, intimal smooth muscle cells of autovein grafts may well become secretory cells, and enhanced platelet adherence could occur during early intimal repair, causing intimal hyperplasia to develop.

Correlation of long-term results of femoropopliteal autogenous vein grafts with shear stress variation. In situ or reversed graft?

To investigate the correlation between blood flow rate and shear stress variation (tau-variation), the integral of time differential of wall shear stress in one cardiac cycle and the outcome of the vein graft, 42 consecutive patients with femoropopliteal autovein grafts (24 in situ and 18 reversed grafts) were followed for 3 months to 5 years after surgical repair. No correlation was noted between the intraoperative blood flow rate and the outcome of the vein grafts with either procedure. In contrast, the tau-variation value of the vein grafts was closely related to their outcome with both procedures. The higher the tau-variation, the better the long-term results. Vein grafts with a tau-variation of over 60 dyn/cm2 showed good long-term results. The in situ grafts tended to have a higher tau-variation than the reversed grafts (67% in the in situ grafts vs 39% in the reversed grafts). Late failures were noted in vein grafts with low tau-variation value within 3 years after surgery. We recommend the in situ graft technique for patients undergoing femoropopliteal reconstruction, with careful follow-up in cases of vein grafts with a low tau-variation value.

Long-term results of arterial reconstruction of lower extremities determined by flow waveform analysis

Arterial reconstructions of the lower extremities were reviewed to assess the usefulness of flow waveform analysis. Six hundred and thirty-four arterial reconstructions were divided into two groups: a former (1965-1973) group of 218 reconstructions not assessed by flow waveform analysis and a recent (1974-1985) group of 416 reconstructions analyzed according to flow waveform. The cumulative patency rates of the former and the recent group at 5 years were as follows: aorto-femoral, 75.2% and 86.7% (P less than 0.05); femoral-distal, 34.6% and 61.5% (P less than 0.001); extra-anatomical, 63.6% and 80.2% (P = 0.06), respectively. Based on the various flow waveforms evidenced intraoperatively, the cumulative patency rate of cases in the recent group with type 0 and I flow waveform was compared to the rate of those with type II flow waveform. The cumulative patency rates at 5 years were as follows: aorto-femoral, 92% and 82.7% (P = 0.15); femoral-distal, 77.7% and 49.3% (P less than 0.001); extra-anatomical, 91.8% and 68.9% (P less than 0.05), respectively. These results indicate that intraoperative flow waveform analysis is a simple and useful indicator for predicting the long-term results of arterial reconstruction.

Flow waveform assessment of polytetrafluoroethylene grafts for reconstruction of lower extremity arteries. A preliminary report

On the basis of our findings that the outcome of reconstructive surgery for lower limbs could well be predicted by flow waveform analysis, we reviewed femoropopliteal arterial bypass operations involving the use of polytetrafluoroethylene (PTFE) grafts for 35 patients. Of 38 grafts, 26 were PTFE alone, and 12 were PTFE/vein composite grafts. Neither ankle pressure index nor angiographic distal runoff was of predictive value as a prognostic indicator. The cumulative patency rate, calculated by the life-table method, revealed the usefulness of flow waveform analysis for prediction of the outcome of PTFE grafts. In type 0 or I flow, the patency rate was 94% at 1 and 2 years and 79% at 3 years. In contrast, in type II flow, the patency rate was 74% at 1 year, 66% at 2 years, and 49% at 3 years, with a statistical significance at 2 and 3 years (p less than 0.05). Comparison of the result of PTFE grafts with that of PTFE/vein composite grafts showed superior results of composite grafts at 3 years after implantation (42% vs. 83%, p less than 0.05). These findings indicate that flow waveform analysis is useful for prediction of the outcome of PTFE grafts and that PTFE/vein composite grafts should probably be used, particularly in cases of abnormal blood flow.

Modified vein allograft for small arterial reconstruction in dogs

The ideal graft for peripheral arterial reconstruction has yet to be developed. We evaluated on the effectiveness of porosity to intimization of the graft. Modified vein allografts newly constructed through digestion of vein allografts with elastase, glutaraldehyde tanning and lyophilization were implanted in thirty-nine canine femoral arteries. These grafts had a higher porosity than conventional vein allografts and the overall patency rate was 70 per cent at 6 months after implantation. Microscopic examination showed that graft interstitial healing and subsequent intimization were completed by ingrowth of connective tissue from outside through the graft wall at 3 weeks and later. Aneurysmal change of the modified vein allografts was never evident. These results indicated that porosity of the graft is indeed an important factor for intimization and durability of grafts, even in bioderivative substitutes.

Esophageal stricture in Crohn's disease--a case report

We treated a 46-year-old Japanese man with Crohn's disease of the esophagus and for whom medical therapy was adequate. Crohn's disease of the esophagus is a rare disease without specific clinical features and establishment of the diagnosis with guided biopsy is extremely difficult. Therefore, Crohn's disease of the esophagus should be considered in the differential diagnosis of biopsy-negative carcinoma of the esophagus in order to avoid major surgery. Treatment of Crohn's disease of the esophagus should primarily be medical and esophagectomy should only be considered in cases of complications, intractability or a suspicion of malignancy in the biopsied specimen.