Branch Vessel Occlusion Research Articles

Use of a Self-expanding Vascular Occluder for Embolization during Endovascular Aortic Aneurysm Repair

Repair of aortic aneurysms with use of stent-graft techniques may require occlusion of large branch vessels to prevent back-bleeding into the excluded aneurysmal sac. The authors describe their experience using a self-expanding vascular occluder (SEVO) to occlude flow in branch arteries during aortic stent-grafting. Eighty-four patients (65 men, 19 women; mean age, 64 years) underwent thoracic (n = 72) or abdominal aortic (n = 12) stent-grafting. Aneurysm repair was performed using nonbifurcated Z stents covered with polyester or polytetrafluoroethylene (PTFE) fabric. SEVOs constructed from a Z stent (10-20 mm diameter) and PTFE were deployed through a separate catheter (14-20 F). Ten of 84 patients required embolization of large branch arteries with use of a SEVO during aortic stent-grafting (thoracic, n = 1; abdominal, n = 9). The SEVO was placed in the common iliac (n = 9) or subclavian artery (n = 1). The mean SEVO diameter was 14.7 mm (range, 10-20 mm). Eight patients undergoing SEVO embolization had immediate thrombosis of the treated artery. One patient required additional embolization with use of conventional coils. No patients had back-bleeding into the aneurysm, device migration, microembolization, or limb ischemia (mean follow-up, 140 days; range, 50-200). All 10 patients had complete thrombosis of the aortic aneurysm. Use of a novel self-expanding vascular occluding device is a safe and effective supplementary technique to occlude high-flow, large-diameter arterial branch vessels during endovascular aortic aneurysm repair.

Functional outcome for patients with hemiparesis, hemihypesthesia, and hemianopsia. Does lesion location matter?

Patients with hemiparesis, hemisensory loss, and hemianopsia ("HHH" deficits) due to stroke may have large cortical lesions caused by middle cerebral trunk vessel occlusion or smaller subcortical lesions due to lenticulostriate involvement. We studied the usefulness of lesion location in predicting functional recovery within this syndrome. We reviewed our records and found 41 patients who had a single ischemic hemispheric stroke, HHH deficits, and an available CT scan performed more than 24 hours after the onset of symptoms. CT scans were read independently and blindly by the authors. Lesions were initially categorized by arterial distribution on the basis of CT templates published by Kinkel. The numerous combinations of arterial branch vessel occlusions observed did not allow for statistical analyses because of the small number of subjects within each subgroup. Lesions were therefore classified as cortical (C), subcortical (S), or mixed (M). There were no significant differences among the three anatomic groups for age, sex, interval after stroke, Mini-Mental Status Examination score, or admission Barthel Index score. Functional outcome measures did not differ significantly for the three groups: mean +/- SD discharge Barthel score (C, 64 +/- 31; S, 47 +/- 20; M, 57 +/- 21), length of stay ([days] C, 64 +/- 25; S, 77 +/- 24; M, 73 +/- 28), and frequency of nursing home placement (C, 4/8; S, 3/6; M, 2/16). For patients with HHH deficits, the anatomic location of the lesion (C versus S versus M) does not affect functional outcome.

Case report: Critical lower limb ischaemia due to aortic dissection relieved by percutaneous transfemoral fenestration

Acute dissection of the aorta has a very high mortality and morbidity, even with optimum treatment. Without therapy, the mortality at three months is reported as 90% [1]. With therapy, the overall in-hospital mortality rate reaches 15% to 20%. Occlusion of aortic branch vessels is a well known and serious complication of acute and chronic aortic dissection, usually requiring urgent surgical intervention. This is associated with a large increase in mortality [2,3]. We have recently performed a percutaneous transfemoral fenestration of the aortic septum in a chronic dissection of the abdominal aorta to relieve unilateral lower limb ischaemia.

Optimizing technical success of renal revascularization: The impact of intraoperative color-flow duplex ultrasonography

Purpose: Technical problems with renal revascularization can be difficult to detect, especially with end points of transaortic renal endarterectomies or anastomosis of bypass grafts to small distal renal arteries. If missed, such technical mishaps may not be recognized until after operation, when the chance for timely renal salvage has often been lost.Methods: To evaluate the value of newer color-flow duplex imaging, we performed intraoperative ultrasonography on 35 patients undergoing revascularization of 64 renal arteries, 29 patients undergoing transaortic endarterectomy, and 6 undergoing bypass grafting. Most patients (2435; 69%) underwent concomitant aortic reconstruction. Ninety-four percent had hypertension, whereas 66% had associated chronic renal insufficiency.Results: Technical abnormalities prompting operative revision were identified during surgery in 10.9% of reconstructed main renal arteries (764). These included two occlusions, three intimal defects, and one extrinsic tissue band after endarterectomy plus one graft anastomotic stenosis. Color-flow imaging revealed all of them. Technical defects were also associated with higher peak-systolic flow velocities (mean 2.62 m/sec; range 2.00 to 3.50 m/sec) than normal-appearing arteries (mean 1.34 m/sec; range 0.40 to 2.50 m/sec) (p = 0.004). Eighty-six percent of the defects (67) were immediately correctable. One patient required nephrectomy. Postoperative angiograms revealed two asymptomatic small branch-vessel occlusions (3%). Compared with preoperative levels (p < 0.01), both hypertension and renal insufficiency improved initially. The clinical outcome of patients requiring intraoperative revision did not differ from that of patients undergoing normal intraoperative studies.Conclusion: Intraoperative color-flow duplex detection and surgical correction of technical problems with renal revascularization have enhanced our technical success and been associated with long-term results comparable to those of patients undergoing normal intraoperative studies.

Evolving strategies for the repair of complex renovascular lesions.

Fifty-five patients with 59 complex renovascular lesions required two or more branch artery anastomoses during aortorenal grafting. Forty-five reconstructions involving 112 branches were facilitated using hypothermic ex vivo perfusion preservation, whereas 14 involving 28 branches were repaired in situ. Ex vivo repair was used whenever the kidney was considered unreconstructable by in situ techniques. Fibromuscular dysplasia predominated and the branched internal iliac artery was used for renal artery substitution. There were no deaths and only one kidney (ex vivo) was lost. Branch vessel occlusion occurred in two of 140 anastomoses (1.4%). Ninety-eight per cent (51/52) of the heparinized patients had cure or improvement at mean follow-up of 5 years. No late graft dysfunction occurred in postoperative angiographic follow-up. The branched internal iliac artery is uniquely suited and remains the preference of the authors for the replacement of the diseased renal artery and its branches. The in situ repair is ideally suited for lesions limited to the renal artery bifurcation. Ex vivo repair is reserved for complex or reoperative distal arterial lesions. Unique characteristics in the group include: bilateral lesions (25%), solitary kidney (22%), reoperative lesions (16%), children (9%), and coexisting significant aortic disease (7%). In situ and ex vivo repair meet all the challenges of complex renovascular disease. The strategies outlined will achieve outstanding long-term total and segmental renal salvage in the treatment of hypertension or aneurysmal disease. When ex vivo repair is required, it can be accomplished with only one additional simple maneuver, the reanastomosis of the renal vein.

Self-expanding metallic stents: preliminary evaluation in an atherosclerotic model.

The performance of the self-expanding stainless steel (Gianturco) stent in atherosclerotic arteries was examined in a rabbit model. Atherosclerosis was induced by supplementing rabbit chow with 6% peanut oil and 2% cholesterol followed by endothelial disruption of the abdominal aorta with a balloon catheter and continuation on the atherogenic diet for the remainder of the study. Eighteen stents, 1 cm in length and 4 or 5 mm in diameter when fully expanded, were placed in atherosclerotic stenotic lesions in six rabbits. Luminal distention was consistently achieved. At 8 weeks follow-up, no luminal narrowing, stent migration, thrombus formation or branch vessel occlusion had occurred. Atherosclerotic neointimal proliferation occurred around the stent wires following placement, but did not cause significant luminal narrowing.

Liver transplant rejection: angiographic findings in 35 patients.

Rejection, the leading cause of liver allograft dysfunction, is usually detected by liver biopsy. The purpose of this study was to determine if there are angiographic findings that correlate with this posttransplantation complication. In a retrospective study, the angiograms of 35 patients with histologically proven allograft rejection were reviewed. The examinations were done because of suspected posttransplantation vascular complications. Abnormal hepatic arteriograms were observed in 30 (86%). Eleven (37%) of the 30 had hepatic artery thrombosis (all had acute rejection). Nineteen (63%) of the 30 had varying degrees of intrahepatic arterial narrowing (14 had acute and five had chronic rejection). Additional findings in patients with acute rejection included stretching of the intrahepatic arterial tree (five cases) and slow flow, poor peripheral arterial filling, and a decrease in the number of intrahepatic arteries (10 cases total). Intrahepatic branch vessel stenoses and occlusions were seen in four patients with chronic rejection. We conclude that there is good correlations between the angiographic findings and histologic evidence of rejection. Although angiography is not advocated as a test for transplant rejection, detection of certain findings raises the possibility of rejection.

Creatine kinase release after successful percutaneous transluminal coronary angioplasty

After successful percutaneous transluminal coronary angioplasty (PTCA), 25 (20%) of 128 patients had elevation of creatine kinase MB isoenzyme (CK-MB). The increase was mild (mean 9% MB with total creatine kinase of 179 U/L). Three variables were significantly related to the enzyme elevation: chest pain, small branch vessel occlusion, and recent myocardial infarction. Of the patients with CK-MB elevation, 60% experienced chest pain and 32% sustained a small branch vessel occlusion during PTCA, compared with 11% and 8%, respectively, of the 103 patients without enzyme elevation ( p < 0.001 and p < 0.01). Of 16 patients with recent myocardial infarction, seven (44%) had release of CK-MB. Although mild enzyme elevation after successful PTCA is likely due to a small amount of myocardial necrosis, this phenomenon was not associated with increased cardiac morbidity or mortality. Therefore, release of CK-MB without other clinical evidence for myocardial infarction after successful PTCA does not in itself warrant longer hospitalization, and routine serial enzyme determinations are probably unnecessary. By reducing the number of laboratory tests and the duration of hospitalization, the cost effectiveness of PTCA may be increased.

Aortic dissection due to translumbar aortography, with recovery following surgery.

Renal and neurological complications are the commonest serious sequelae of abdominal aortography. It has become increasingly evident that in some cases these occasionally fatal complications have been brought about by aortic mural dissection following the injection of dye, with partial or complete occlusion of aortic branch vessels. That this sequence of events can occur was strongly suspected by Gaylis and Laws,¹who produced medial dissection experimentally in human abdominal aortas. However, McAfee,²in a review of data on over 12,000 aortograms, was able to collect only two cases of dissection following aortography, both of which ended fatally. On the other hand, Wolfman and Boblitt³reported four fatal cases from a series of 302 aortograms. In two of these the dissection directly contributed to the death. Fineberg and his associates⁴described a case of gangrene of the large intestine believed to have resulted from this mechanism. Since