Stenting of the iliac arteries with the Palmaz stent: Experience from a multi-center trial

JOURNAL

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Interventional radiology in the maintenance of infrainguinal vein graft patency London NJM, SayersRD, Thompson MM, Naylor AR, Hartshorne T, Ratliff DA, Bell PRF, Bolia A. Br J Surg 1993;80:187-93 Backpound: This study was designed to assessthe value of close surveillance of infrainguinal autogenous vein bypass grafts and the utility of performing interventional radiologic procedures (percutaneous transluminal angioplasty [PTA] of stenoses, embolization of persistent arteriovenous fist&s and thrombolytic/aspiration therapy) to salvage failing grafts. Methods and Results: One hundred twelve consecutive infrainguinal bypass grafts were investigated. After a l-month baseline examination, patients were studied at 3-month intervals for the first year and every 6 months thereafter with use of ankle pressure indexes and duplex scanning. Arteriograms were obtained for 10% decreasesin ankle indexes (at rest or after exercise) or for a segmental duplex peak velocity ratio greater than 3, and all stenoses were treated by PTA. The Society for Vascular Surgery/International Society for Cardiovascular Surgery standards for reporting patency were used. Most grafts were in situ (71%), placed to the tibia1 vessels (68%), and performed for rest pain/tissue loss (87%). Twenty percent of grafts had irreversibly occluded by 1 month. Primary, primary assisted, and secondary patency rates at 42 months were 4096, 65%, and 69%, respectively. Overall, 33 stenosesin 30 grafts were identified and treated by PTA. Mean time of presentation was 7 (range 1 to 36) months. Most stenoses occurred in the distal third of the graft, half of these at the distal anastomosis; 94% of stenoseswere lessthan 2 cm in length. Primary PTA was successfulin 70% of cases;16% of grafts required one or more angioplasties, and operative revision was performed in four patients. Median follow-up after PTA was 19 (1 to 40) months, and 41% of stenosis did not recur after at least 2 years follow-up. Thrombolytic or emboliiation procedures were performed in four grafts. Summary The authors conclude that a strict policy of noninvasive surveillance of infrainguinal saphenous vein grafts is advisable becauseit disclosed a substantial number of asymptomatic stenoses. They contend that interventional radiology has a crucial role to play in the maintenance of bypass patency and that PTA is a highly effective treatment. Comnents: Although aggressivevein graft surveillance is rapidly gaining widespread acceptanceand use, this study does not provide convincing evidence for its conclusions. A very “mixed bag” of interventions is presented; the authors would have done well to eliminate the small number of tbrombolytic casesand emboliiations. An unusually high rate of early occlusions (20%) is described, raising the specter of technical misadventures. A mean follow-up time is not given, with only 28 grafts at risk at the 42-month surveillance, suggesting that a substantial number were assessedfor a relatively short period. The median follow-up

SURGERY October

Abstracts

1994

after PTA was 19 months with a wide range and the authors’ statement that “Twelve of the 29 stenoses(41%) had not recurred after at least 2-year follow-up” is confusing and leads one to wonder whether 59% did recur. Relatively short follow-up in conjunction with relatively short lesions ( < 2 cm) may explain the apparent successof PTA for vein graft stenoses. William

C. Knbpski,

Univmity of Colon& Denver, Co[o.

MD Health

Sciences Center

Stenting of the iliac arteries with the Palmaz stew Experience from a multi-center trial Palmaz JC, Lagorde JC, Rivera FJ, Encarnacion CE, Lutz JD, Moss JG. Cardiovasc Interv Radio1 1992;15:291-7. Background: Based on favorable results from preliminary studies, use of balloon-expandable endoluminal metallic stems has been approved for treatment of iliac artery occlusivedisease.This report further investigates the safety and utility of this form of treatment, presenting results of iliac artery stenting with the Palmaz endoluminal stent (Johnson & Johnson, New Brunswick, N.J.) in a large number of patients entered into a multicenter evaluation of this device. Although this study has been underway for 5 years, most patients have relatively short follow-up; therefore this must be considered an interim report. Methods and Restilts: The results of 486 patients undergoing 587 procedures were reviewed. Sixty-eight percent of patients were treated for claudication, and treated lesions were relatively short (mean length 3.2 cm). Initial improvement in symptoms was seen in 99.2% of patients, and ankle brachial indexes increasedfrom a mean of 0.62 before therapy to a mean of 0.8 immediately after the procedure. However, clinical improvement was maintained in only 69% of patients after 43 months of follow-up. Two hundred one patients had follow-up arteriograms and 92% of these patients were found to have patent stents without evidenceof restenosisor occlusion at a mean of 8.7 months after iliac artery stenting. Arteriography also demonstrated that the primary cause of recurrent symptoms after iliac artery stenting was disease progression proximal and distal to the area of stenting, which occurred at a rate of approximately 5% per year. Restenosis greater than 50% was seenin 15 stented common iliac arteries and one stented external iliac artery. Procedure related complications occurred in 9.9% of patients, primarily because of insertion site problems. Acute stent thrombosis occurred in five patients but resulted in lib lossin none. Long-term limb lossoccurred in 1.9% of patients becauseof progression of diseaserather than stent restenosis or occlusion. Summary: Initial results of iliac artery stenting with use of the Palmaz stent are good (initial clinical improvement in greater than 90% of patients), and the complication rate after stent placement is acceptable. However, disease progression in adjacent arteries continues so that longterm, clinical improvement is lesssatisfactory (69% at 43

JOURNAL OF VASCULAR Volume 20, Number 4

SURGERY

months) despite minimal vesselrestenosisor reocdusion at the site of the stent. Comments: This study confirms the initial efficacy and safety of iliac artery stenting with use of the Palmaz stent. In addition, as the delivery system for the Palmaz stent has been reduced in size, it is expected that the complication rate associated with the procedure is now lower than that reported in this study. However, these good results with use of metallic endoluminal stems in iliac arteries cannot be generalized to use of such stents in infrainguinal arteries where the acute thrombosis rate has been high. The decline in clinical successover time associatedwith progression of diseaseat untreated sites also demonstrates the problems associatedwith local treatment of aortoiliac arterial occlusive disease, particularly when compared with results of surgical bypass with use of an aortobifemoral graft. M. Seeger,MD of Fhidu Gainesville, Flu.

James

lJni9edy

Effects of oxygen inhalation on skin microcirculation in patients with peripheral arterial occlusive disease Bongard 0, Bounameaus H, Fagell B. Circulation 1992; 86878-86.

Backgroznd: Supplemental oxygen is used clinically to improve oxygen delivery to peripheral tissues. Oxygen delivery is determined by the oxygen content and the blood flow. However, maldistribution or vasoconstriction of lower extremity circulation may occur with increased oxygen tension, thus lowering both skin perfusion and oxygen delivery. Because conflicting results have been reported on the circulatory effects of oxygen on ischemic tissues,this study was designed to investigate the effect of 40% oxygen inhalation on the skin microcirculation and oxygen delivery in the feet of patients with peripheral arterial occlusive disease(PAOD). Methods and Res&: Transcutaneous oxygen tension (tc PoJ was measured on the dorsal skin at the level of the first metatarsal, whereas skin temperature, laser Doppler flow, and capillary blood cell velocity were measured in the nailfold area of the first toe in 17 legs of 11 patients with PAOD. Similar measurements in 13 legs of eight control subjects provided control data. After equilibration, continuous measurements were made with the patient breathing room air, fractional concentration of oxygen in inspired gas of 40%, and room air. Inhalation of oxygen in normal subjects significantly increased tc PO, at both fractional concentration of oxygen in inspired gas of 40% and 100% (p < 0.002). In patients with PAOD, oxygen inhalation changed tc PO, to a variable extent. Two groups were identified - those whose tc PO, increasedand those whose tc PO, did not. The ability to increasetc PO, was correlated with a more severe degree of ischemia (angiographic and systolic toe pressure criteria) (x” = 7.13, p < 0.008). Inhalation of oxygen induced a significant decreaseof both the total (ALDF, -307%, p < 0.02) and nutritional (ACBV, - 17%, p < 0.002) skin microcirculation in

Abstracts 673

normal legs compared with baseline values. A similar response was observed in 10 legs of patients who showed a significant increaseof the tc PO, ( > 10 mm Hg) (ALDF, - 14%, NS; ACBV, - 13%,p < 0.005). By contrast, both the total (+21%, p < 0.03) and nutritional (+ 5296, p < 0.05) circulations significantly increased in the seven legs without significant tc PO, increase. Summary: Inhalation of 40% oxygen induced a dosedependent reduction in blood flow to the skin microcirculation of toes of the normal subjects, confirming the vasoconstrictive effects of increased oxygen tension. In patients with moderate ischemia, vasomotor reactivity is impaired but not abolished. Cutaneous blood flow decreasedin these patients, but not to the same extent as in control subjects. In patients with severe ischemia, the vasoconstrictor responseto oxygen is lost and a paradoxical increase in blood flow occurs with oxygen supplementation. This may be the result of blood being shunted from the normal to the ischemic tissue after oxygen-induced vasoconstriction of the normal tissue. Cumments: This intriguing report addressesthe cutaneous microvascular response of normal versus ischemic toes to supplemental oxygen inhalation. The disparity between transcutaneous oxygen measurements and blood flow responsesto oxygen inhalation is postulated to be due to the abolishment of normal vasomotor responses by severe ischemia. However, because some of the patients with PAOD had diabetes mellitus, this conclusion could be strengthened by studying patients with diabetes to assess the relative effects of diabetic microvascular changes versus proximal atherosclerosis. Certainly the observation that oxygen inhalation may be detrimental to cutaneous circulation may have practical application in patients with cutaneous ischemia or ulcers. Hawy L. Bush, Jr., MD New York Hozpital-Cm11 New York, N.T

Medic& Center

Renal artery aneurysm: Surgical indications and results Hupp T, Allenberg JR, Post K, Roeren T, Meier M, Clorius JH. Eur J Vast Surg 1992;6:477-486. Background: By reporting 28 renal artery aneurysms treated over 10 yearsin 23 consecutive patients, the authors foster credibility in their conclusions and recommendations. All patients were included and the lesionshad a wide variety of presentations and causes; the series comprised “all-comers” in a way that resembles the practice of the average practicing vascular surgeon. In fact, the clinical, angiographic, and pathologic features characterizing these lesions were so diverse that they could be categorized into as many groups as there were patients. So much heterogeneity was a strength of the study, but, because the population was relatively small, it was also one of its weaknesses. Metbodr and Reszks: Thirty-five percent of the aneurysms were detected during the investigation of hypertension, whereas 26% were incidental discoveries during