Portopulmonary venous anastomosis in balloon-occluded retrograde transvenous obliteration for the treatment of gastric varices.

BACKGROUND AND AIM: Several reports have described portopulmonary venous anastomosis (PPVA). However, in balloon-occluded retrograde transvenous obliteration (BRTO), attention has not been paid to paradoxical embolism. The objective of this study was to investigate the existence of a right-left shunt due to PPVA when the drainage vein is occluded by a balloon during BRTO. METHODS: The subjects were 19 patients who underwent BRTO. Whether PPVA was present was confirmed on balloon-occluded retrograde transvenous venography (BRTV). After BRTV, a retrograde bolus injection of 20 mL of carbon dioxide (CO2 ) via the balloon catheter was performed under balloon occlusion, and the flow of bubbles into both ventricles was observed with four-chamber view echocardiography. During the same balloon occlusion, bolus injection of CO2 into the inferior vena cava was performed, followed by echocardiography. RESULTS: PPVA was confirmed on BRTV in four patients (21.1%). On echocardiography with retrograde CO2 injection, bubbles were confirmed in the left ventricle in six patients (31.6%). On echocardiography with CO2 injection into the inferior vena cava, bubbles were not confirmed in the left ventricle in any cases. CONCLUSIONS: When the draining vein was occluded with a balloon and blood flow in a gastrorenal or gastrocaval shunt was stopped during BRTO, PPVA was confirmed in 21.1% of cases on retrograde angiography, and a right-left shunt was confirmed in 31.6% of cases on echocardiography.

Efficacy of carbon dioxide for diagnosis and intervention in patients with failing hemodialysis access.

BACKGROUND: Carbon dioxide (CO2) is the only proven safe intravascular contrast agent in renal failure and contrast allergy. The use of CO2 as a contrast agent for the evaluation of failing dialysis fistulas has the potential to preserve residual renal function by eliminating the use of contrast material or decreasing the amount used for fistulograms. PURPOSE: To evaluate the feasibility of fistulography using CO2 for diagnosis and intervention in patients with failing hemodialysis access. MATERIAL AND METHODS: Dialysis access failure occurred in 94 patients (54 men, 40 women; mean age, 65 years; range, 32­89 years) on 146 occasions. CO2 was used as the first-choice contrast agent for fistulography and PTA. Fistulography was performed with the injection of CO2 in the brachial artery using a power injector. RESULTS: Interventional treatment was indicated in 141 accesses. In 115 of these 141 cases, intervention was performed using CO2 fistulography alone. When the access flow stopped or decreased very much due to an occlusion and severe stenosis, we could not visualize the access by CO2 fistulography, or could not perform CO2 fistulography. For those cases, iodinated contrast fistulography was performed. When the vascular rupture, dissection, or clot formation occurred during intervention, iodinated contrast fistulography was performed. In three patients with arteriovenous fistula, manual injection of CO2 into the brachial artery resulted in reflux of the gas into the thoracic aorta causing transient loss of consciousness. CONCLUSION: CO2 is a useful contrast agent in the diagnosis and intervention of failing hemodialysis access, eliminating or limiting the use of iodinated contrast material. Caution should be exercised to prevent CO2 reflux into the aorta when injecting the gas into the brachial artery.

Transcatheter embolization for peripheral pseudoaneurysms with n-butyl cyanoacrylate.

The purpose of this study is to evaluate the clinical efficacy of transcatheter embolization for pseudoaneurysms of peripheral arteries with n-butyl cyanoacrylate (NBCA). From November 2000 to February 2008, 17 patients with 18 pseudoaneurysms were treated by transcatheter embolization at our affiliated hospitals. The locations of the pseudoaneurysms were right hepatic artery (n=3), renal artery (n=5), splenic artery (n=2), gastroduodenal artery (n=2), common hepatic artery (n=1), pancreatic arcade (n=1), external iliac artery (n=1), internal iliac artery (n=1), internal thoracic artery (n=1), and left gastric artery (n=1). We assessed technical success rate, embolization methods, and clinical course in this study. The technical success rate was 94.4% (17/18 cases). Embolization methods were isolation (n=17) and packing (n=1). Only NBCA was used in 14 cases, both coils and NBCA were used in four cases. Six patients were in shock prior to the procedure, but all patients recovered immediately after embolization procedure including transfusion. None of the patients died of procedure-related factors or had notable postoperative complications, but three patients died within a week of the procedure because of deterioration of the underlying disease. In conclusion, transcatheter embolization of pseudoaneurysms with NBCA is a safe and effective technique for treatment.

Residual stenosis after conventional balloon angioplasty for hemodialysis shunt failure: treatment with metallic stent placement and post-balloon dilatation.

PURPOSE: The usefulness of metallic stent placement and post-balloon dilatation was investigated for patients with residual stenosis after conventional percutaneous transluminal balloon angioplasty (balloon PTA) of dialysis shunt vessels. MATERIALS AND METHODS: Among 92 patients who had received balloon PTA for dialysis shunt vessels, seven patients who showed a residual waist on the balloon even under maximum inflation were enrolled in this study. In these patients with residual stenosis after balloon PTA, we inserted a stent in the residual stenosis, and post-balloon dilatation was immediately applied using the same balloon catheter. RESULTS: After balloon PTA, the average percent diameter stenosis declined to 45.5 +/- 7.30%, and the stenosis was further improved to an average of 19.3 +/- 7.09% after the placement of a stent and the additional balloon PTA. The average percent diameter dilatation of the balloon before the placement of a stent was 65.8 +/- 12.7%, while the average dilatation increased to 84.1 +/- 8.96% after the placement of a stent. Dialysis became possible immediately after the procedure in all cases. CONCLUSION: Metallic stent placement and post-balloon dilatation was effective for patients with residual stenosis after conventional balloon PTA of dialysis shunt vessels.

Peripheral stent placement in hemodialysis grafts.

The purpose of the present study was to evaluate the clinical outcome of peripheral stent placement after failed balloon angioplasty in patients with grafts who are on hemodialysis. We examined 30 Wallstents that were placed in 26 patients because balloon angioplasty failed or early restenosis (<3 months) occurred within 3 months. We retrospectively reviewed 267 consecutive balloon angioplasties performed in 71 patients with graft access between August 2000 and March 2007. Stent placements accounted for 30 (11.2%) of the 267 balloon angioplasties. The clinical success rate of stent placement was 93.3% (28 of 30 stent placements). The 3-, 6-, and 12-month primary patency rates were 73.3%, 39.3%, and 17.7%, respectively. The 1-, 2-, and 3-year secondary patency rates were 90.2%, 83.8%, and 83.8%, respectively. Primary patency was significantly prolonged by stent placement after early restenosis compared with previous balloon angioplasty alone (P = 0.0059). Primary patency after stent placement was significantly lower than after successful balloon angioplasty without indications for stent placement (P = 0.0279). Secondary patency rates did not significantly differ between stent placement and balloon angioplasty alone. The mean number of reinterventions required to maintain secondary patency after stent placement was significantly larger than that after balloon angioplasty alone (Mann-Whitney U test, P = 0.0419). We concluded that peripheral stent placement for graft access is effective for salvaging vascular access after failed balloon angioplasty and for prolonging patency in early restenosis after balloon angioplasty. However, reinterventions are required to maintain secondary patency after stent placement. Furthermore, peripheral stent placement for graft access cannot achieve the same primary patency as balloon angioplasty alone.

Primary patency with cutting and conventional balloon angioplasty for different types of hemodialysis access stenosis.

PURPOSE: To compare primary patency rates of cutting balloon percutaneous transluminal angioplasty (PTA) (hereafter, cutting PTA) and conventional balloon PTA (hereafter, conventional PTA) in the treatment of different types of hemodialysis access stenosis. MATERIALS AND METHODS: The institutional review board approved this study. Written informed consent was obtained for the prospective component of this study and waived for the retrospective component. Patients in whom treatment with cutting PTA alone or conventional PTA alone was clinically successful formed the two study groups. Primary patency for the lesion was defined as uninterrupted patency of the treated site after balloon PTA. A site was no longer considered patent when the patient underwent treatment for hemodialysis access failure due to restenosis of the treated site. Primary patency rates for lesions were calculated with the Kaplan-Meier method according to the type of stenosis. We compared the two groups by using the log-rank test to determine statistical significance. RESULTS: In the cutting PTA group, 62 patients with 77 stenoses (32 men, 30 women; mean age, 65.5 years +/- 10.1 [standard deviation]) achieved clinical success. In the conventional PTA group, 52 patients with 68 stenoses (23 men, 29 women; mean age, 61.9 years +/- 10.2) achieved clinical success. In patients with autogenous venous stenosis, no significant difference in the primary patency rate was noted between groups (P = .369). In patients with graft-to-vein anastomotic stenosis, the primary patency rate was significantly higher for cutting PTA than for conventional PTA (P = .39). In patients with intragraft stenosis, no significant difference in the primary patency rate was noted between groups (P = .379). In patients with in-stent restenosis, no significant difference in the primary patency rate was noted between groups (P = .923). CONCLUSION: Primary patency rates are significantly higher for cutting PTA in the treatment of graft-to-vein anastomotic stenosis; however, no significant differences in primary patency rates exist between these PTAs in the treatment of autogenous venous stenosis, intragraft stenosis, or in-stent restenosis.

Radiofrequency ablation combined with CO2 injection for treatment of retroperitoneal tumor: protecting surrounding organs against thermal injury.

OBJECTIVE: The objective of this study was to separate target tumors from adjacent structures by injecting carbon dioxide (CO2) around the tumor to avoid thermal injury and the heat-sink effect from the blood vessel during percutaneous radiofrequency ablation. CONCLUSION: We successfully achieved complete ablation of a retroperitoneal tumor without thermal injury. Imaging-guided percutaneous CO2 injection is useful for preventing thermal injury while achieving complete ablation of the tumor during radiofrequency ablation.