Vitamin D and Vulnerable Carotid Plaque.

BACKGROUND AND PURPOSE: MR imaging-detected carotid intraplaque hemorrhage indicates vulnerable plaque with high stroke risk. Angiotensin II stimulates intraplaque hemorrhage in animal models, and the angiotensin system is highly regulated by vitamin D. Our purpose was to determine whether low vitamin D levels predict carotid intraplaque hemorrhage in humans. MATERIALS AND METHODS: In this cross-sectional study, 65 patients with carotid disease underwent carotid MR imaging and blood draw. Systemic clinical confounders and local lumen imaging markers were recorded. To determine the association of low vitamin D levels with MR imaging detected intraplaque hemorrhage, we performed multivariable Poisson regression by using generalized estimating equations to account for up to 2 carotid arteries per patient and backward elimination of confounders. MR imaging detected intraplaque hemorrhage volume was also correlated with vitamin D levels and maximum plaque thickness. Thirty-five patients underwent carotid endarterectomy, and histology-detected intraplaque hemorrhage was correlated with vitamin D levels and total plaque area. RESULTS: Low vitamin D levels (<30 ng/mL, prevalence ratio = 2.05, P = .03) were a significant predictor of MR imaging detected intraplaque hemorrhage, along with plaque thickness (prevalence ratio = 1.40, P < .001). MR imaging detected intraplaque hemorrhage volume linearly correlated with plaque thickness (partial r = 0.45, P < .001) and low vitamin D levels (partial r = 0.26, P = .003). Additionally, histology-detected intraplaque hemorrhage area linearly correlated with plaque area (partial r = 0.46, P < .001) and low vitamin D levels (partial r = 0.22, P = .03). The association of intraplaque hemorrhage volume with low vitamin D levels was also higher with ischemic stroke. CONCLUSIONS: Low vitamin D levels and plaque thickness predict carotid intraplaque hemorrhage and outperform lumen markers of vulnerable plaque. This research demonstrates a significant link between low vitamin D levels and carotid intraplaque hemorrhage.

Prediction of Carotid Intraplaque Hemorrhage Using Adventitial Calcification and Plaque Thickness on CTA.

BACKGROUND AND PURPOSE: Carotid intraplaque hemorrhage is associated with stroke, plaque thickness, stenosis, ulceration, and adventitial inflammation. Conflicting data exist on whether calcification is a marker of plaque instability, and no data exist on adventitial calcification. Our goal was to determine whether adventitial calcification and soft plaque (a rim sign) help predict carotid intraplaque hemorrhage. MATERIALS AND METHODS: This was a retrospective cohort study of 96 patients who underwent carotid MRA and CTA within 1 month, from 2009 to 2016. We excluded occlusions (n = 4) and near occlusions (n = 0), leaving 188 carotid arteries. Intraplaque hemorrhage was detected by using MPRAGE. Calcification, adventitial pattern, stenosis, maximum plaque thickness (total, soft, and hard), ulceration, and intraluminal thrombus on CTA were recorded. Atherosclerosis risk factors and medications were recorded. We used mixed-effects multivariable Poisson regression, accounting for 2 vessels per patient. For the final model, backward elimination was used with a threshold of P < .10. Receiver operating characteristic analysis determined intraplaque hemorrhage by using the area under the curve. RESULTS: Our final model included the rim sign (prevalence ratio = 11.9, P < .001) and maximum soft-plaque thickness (prevalence ratio = 1.2, P = .06). This model had excellent intraplaque hemorrhage prediction (area under the curve = 0.94), outperforming the rim sign, maximum soft-plaque thickness, NASCET stenosis, and ulceration (area under the curve = 0.88, 0.86, 0.77, and 0.63, respectively; P < .001). Addition of the rim sign performed better than each marker alone, including maximum soft-plaque thickness (area under the curve = 0.94 versus 0.86, P < .001), NASCET stenosis (area under the curve = 0.90 versus 0.77, P < .001), and ulceration (area under the curve = 0.90 versus 0.63, P < .001). CONCLUSIONS: The CTA rim sign of adventitial calcification with internal soft plaque is highly predictive of carotid intraplaque hemorrhage.

Optimal Prediction of Carotid Intraplaque Hemorrhage Using Clinical and Lumen Imaging Markers.

BACKGROUND AND PURPOSE: MR imaging detects intraplaque hemorrhage with high accuracy by using the magnetization-prepared rapid acquisition of gradient echo sequence. Still, MR imaging is not readily available for all patients, and many undergo CTA instead. Our goal was to determine essential clinical and lumen imaging predictors of intraplaque hemorrhage, as indicators of its presence and clues to its pathogenesis. MATERIALS AND METHODS: In this retrospective cross-sectional study, patients undergoing stroke work-up with MR imaging/MRA underwent carotid intraplaque hemorrhage imaging. We analyzed 726 carotid plaques, excluding vessels with non-carotid stroke sources (n = 420), occlusions (n = 7), or near-occlusions (n = 3). Potential carotid imaging predictors of intraplaque hemorrhage included percentage diameter and millimeter stenosis, plaque thickness, ulceration, and intraluminal thrombus. Clinical predictors were recorded, and a multivariable logistic regression model was fitted. Backward elimination was used to determine essential intraplaque hemorrhage predictors with a thresholded 2-sided P < .10. Receiver operating characteristic analysis was also performed. RESULTS: Predictors of carotid intraplaque hemorrhage included plaque thickness (OR = 2.20, P < .001), millimeter stenosis (OR = 0.46, P < .001), ulceration (OR = 4.25, P = .020), age (OR = 1.11, P = .001), and male sex (OR = 3.23, P = .077). The final model discriminatory value was excellent (area under the curve = 0.932). This was significantly higher than models using only plaque thickness (area under the curve = 0.881), millimeter stenosis (area under the curve = 0.830), or ulceration (area under the curve= 0.715, P < .001). CONCLUSIONS: Optimal discrimination of carotid intraplaque hemorrhage requires information on plaque thickness, millimeter stenosis, ulceration, age, and male sex. These factors predict intraplaque hemorrhage with high discriminatory power and may provide clues to the pathogenesis of intraplaque hemorrhage. This model could be used to predict the presence of intraplaque hemorrhage when MR imaging is contraindicated.

Factors influencing ulcer healing in patients with combined arterial and venous insufficiency.

PURPOSE: The purpose of this study was to determine the effectiveness of treatment of patients with combined arterial and venous insufficiency (CAVI), evaluate variables associated with successful ulcer healing, and better define criteria for interventional therapy. STUDY DESIGN: We retrospectively reviewed the records of patients treated at four institutions from 1995 to 2000 with lower extremity ulcers and CAVI. Arterial disease was defined as an ankle/brachial index less than 0.9, absent pedal pulse, and at least one in-line arterial stenosis > 50% by arteriography. Venous insufficiency was defined as characteristic clinical findings and duplex findings of either reflux or thrombus in the deep or superficial system. Clinical, demographic, and hemodynamic parameters were statistically analyzed with multiple regression analysis and correlated with ulcer healing and limb salvage. RESULTS: Fifty-nine patients with CAVI were treated for nonhealing ulcers that had been present from 1 to 39 months (mean, 6.4 months). All patients had edema. The mean ankle/brachial index was 0.55 (range, 0-0.86). Treatment included elastic compression and leg elevation in all patients and greater saphenous vein stripping in patients with superficial venous reflux. Fifty-two patients underwent arterial bypass grafting, three underwent an endarterectomy, one underwent superficial femoral artery percutaneous transluminal angioplasty, and three underwent primary below-knee amputation. For purposes of analysis, patients were divided into four groups according to the pattern of arterial and venous disease and the success of arterial reconstruction. Group 1 consisted of 22 patients with a patent arterial graft, superficial venous incompetence, and normal deep veins. Group 2 consisted of seven patients with a patent graft, superficial reflux, and deep venous reflux. Group 3 included 22 patients with a patent graft and deep venous thrombosis (DVT), and group 4 included eight patients with an occluded arterial graft. Follow-up ranged from 2 to 47 months (mean, 21.6 months). Forty-nine patients remained alive, and 10 died of unrelated causes. During follow-up, 48 of the 56 treated arteries remained patent and eight occluded. Thirty-four ulcers (58%) healed, 18 ulcers (31%) did not heal, and 7 patients (12%) required below-knee amputation for nonhealed ulcers and uncontrolled infection. No patient with graft occlusion was healed, and 12 ulcers persisted despite successful arterial reconstruction. Twenty-one (78%) of 27 patients undergoing greater saphenous vein stripping were healed, but none of these patients had DVT. The mean interval from bypass graft to healing was 7.9 months. Thirty-two (68%) of 46 patients without prior DVT were healed, whereas only two (15%) of 13 patients with prior DVT were healed, and this variable, in addition to graft patency, was the only factor statistically significant in predicting healing (P <.05). CONCLUSIONS: Ulcers may develop anywhere on the calf or foot in patients with CAVI, and healing requires correction of arterial insufficiency. Patients with prior DVT are unlikely to heal, even with a patent bypass graft. Ulcer healing is a lengthy process and requires aggressive treatment of edema and infection, and successful arterial reconstruction. Patients with a prior DVT are unlikely to benefit from aggressive arterial or venous reconstruction.

Wound infections involving infrainguinal autogenous vein grafts: a current evaluation of factors determining successful graft preservation.

PURPOSE: The purpose of this study was to review the natural history and clinical outcome of patients with infrainguinal autogenous graft infection (IAGI), to evaluate the effectiveness of attempted graft preservation, to determine those variables associated with graft salvage, and to better determine optimal treatment. STUDY DESIGN: We retrospectively reviewed the records of patients undergoing infrageniculate vein grafts at three hospitals between 1994 and 2000 who had a wound infection involving the graft. Clinical and bacteriologic variables were analyzed and correlated with graft salvage, limb salvage, and clinical outcome. RESULTS: During this 7-year period, 487 patients underwent an infrageniculate vein graft, and 68 (13%) had clinical evidence of IAGI. Twenty-seven patients presented with drainage from the wound, 15 with wound separation and cellulitis, 18 with soft tissue infection extending to the graft, 4 with an abscess and cellulitis, and 4 with bleeding. Ten patients (15%) had systemic symptoms (defined as a white blood cell count > 15,000 and temperature > 38.5 degrees C). Forty infections developed in the thigh, 17 in the groin, and 11 in the lower leg. An anastomosis was exposed in 15 patients. Wound cultures were positive for bacteria in 52 patients, and most infections were due to Staphylococcus aureus (18 patients) and S epidermidis (12 patients). Pseudomonas was cultured from seven infections. Twelve patients had polymicrobial infections. The interval from operation to infection ranged from 7 to 180 days. All patients were treated with oral antibiotics, 48 after intravenous antibiotics. Forty-five patients had operative debridement, including 18 who had muscle flap coverage. Four patients presented with hemorrhage, and three had immediate graft ligation and one graft excision. Follow-up ranged from 5 to 68 months (mean, 24.3 months), with 61 patients currently alive. Two patients died as a result of the IAGI (mortality rate, 2.9%). One had undergone a below-knee amputation, and one had a nonhealed wound but intact limb. Overall, 61 wounds (91%) healed, 4 patients required below-knee amputations, and 3 wounds did not heal. Fifty-eight grafts remained patent, 6 thrombosed, and 4 were ligated to control hemorrhage. Of the 61 wounds that healed, the time required for healing ranged from 7 to 63 days. No patient with bleeding died because of the acute episode. No patient had delayed hemorrhage. All 18 patients treated with a muscle flap healed. Bleeding (P <.001), elevated white blood cell count (P <.029), fever (P <.001), and renal insufficiency (creatinine level > 1.5; P <.056) were the only variables statistically significant in predicting graft failure or limb loss. With the use of life-table analysis, graft patency was 94%, 72%, and 72% at 1, 3, and 5 years, and limb salvage was 97%, 92%, and 92% at the same intervals, respectively. CONCLUSIONS: Most patients with an IAGI can be successfully treated with graft and limb preservation. In contrast to earlier studies, an exposed anastomosis, interval to infection, or Pseudomonas infection is not associated with graft failure. Graft salvage is less likely in patinets with fever, leukocytosis, and renal insufficency, but because most grafts remained patent, graft preservation is recommended for these patients. Graft ligation or excision should be reserved for patients presenting with bleeding or sepsis.

Incidentally detected stenoses proximal to grafts originating below the common femoral artery: do they affect graft patency or warrant repair in asymptomatic patients?

OBJECTIVE: Stenoses in infrageniculate arteries proximal to a lower extremity vein graft may reduce flow velocity through the bypass graft and are thought to predispose to graft occlusion. Repair of these lesions has been recommended to preserve graft function. This study was undertaken to better define the natural history of grafts below inflow lesions and to evaluate the necessity of repair to preserve graft patency. METHODS: From 1994 through 1999, patients undergoing lower extremity vein grafts by a single surgeon at a university hospital and an affiliated teaching hospital were placed in a prospective protocol for proximal infrageniculate native artery and graft surveillance through use of duplex scanning. The records of those patients with grafts originating distal to the common femoral artery were evaluated; they form the basis for this report. Arteriograms were obtained before bypass grafting, and no patient had a stenosis greater than 50% diameter reduction proximal to the graft origin. Follow-up scans were obtained from the common femoral artery through the graft and outflow artery. The peak systolic velocity and velocity ratio in an infrageniculate native artery proximal to the graft origin were recorded, as were the location and the time interval since the bypass graft. Repair of these proximal lesions was not performed during the course of this study. Revision of the bypass graft or its anastomoses was undertaken according to preestablished duplex scan criteria. RESULTS: During this time, 288 autogenous infrainguinal bypass grafts were performed, of which 159 originated below the common femoral artery; of these, 74 were from the superficial femoral artery, 29 from the profunda femoris artery, 49 from the popliteal artery, and 7 from a tibial artery. The maximum peak systolic velocity proximal to the graft origin was more than 250 in 38 arteries (25%) and more than 300 in 26 arteries (16%). The velocity ratio was 3.0 or more in 32 arteries at the same location as the peak systolic velocity and 3.5 or more in 23 arteries (15%), confirming hemodynamically significant stenoses at these sites. The location of peak systolic velocity was the common femoral artery in 81 patients (51%), the superficial femoral artery in 50 (31%), the popliteal artery in 22 (14%), and a tibial artery in 6 (4%). Follow-up ranged from 8 to 60 months (mean, 35 months). During follow-up, 19 patients died, 18 with patent grafts. Overall, nine grafts occluded. One of the occluded grafts had a velocity ratio greater than 3.0; this may have contributed to graft thrombosis. The other occlusions resulted from an unrepaired graft lesion in 2 patients, graft infection in 2 patients, and graft ligation necessitated by below-knee amputation in 2 patients. No cause for the occlusion could be identified in two of the grafts (neither had evidence of proximal arterial stenosis). Assisted primary patency rates were 95% and 91% at 3 and 5 years, respectively. CONCLUSIONS: For grafts originating distal to the common femoral artery, stenoses proximal to the graft do not affect bypass graft patency and do not require repair to prevent graft occlusion. Surveillance of these lesions may therefore be unnecessary, inasmuch as the repair of proximal lesions should not be undertaken to preserve graft function.

Stent placement for treatment of central and peripheral venous obstruction: a long-term multi-institutional experience.

PURPOSE: The clinical success and patency of central and peripheral venous stents in patients with symptomatic venous obstruction (SVO) were assessed. METHODS: The records of patients with SVO treated with venous stents from 1992 to 1999 were reviewed. Demographic and procedural variables were analyzed to determine their effect on clinical success, primary patency, and secondary patency. Patency was determined by means of a follow-up duplex scan or venogram. RESULTS: Forty central venous (CV) and 14 peripheral venous (PV) obstructions were treated in 49 patients. Sixty-five stents were placed (50 CV and 15 PV), 54 in previously unstented lesions and 11 in previously stented lesions. Causes of CV lesions included catheter placement (82%), tumor compression (6%), arteriovenous fistula (AVF) and no prior catheter (2%), and other (10%). All PV lesions resulted from complications of dialysis. Indications for CV stents included limb edema (46%), AVF malfunction (30%), both limb edema and AVF malfunction (14%), and other (10%). PV stent indications were AVF malfunction (86%) and limb edema (14%). Thirteen CV stents indicated to treat tumor compression (three cases), May-Thurner syndrome (one case), deep venous thrombosis (three cases), superior vena cava syndrome (one case), and lower-extremity catheter-related lesions (five cases) were excluded from the analysis of clinical outcome. Fifty-two stents (37 CV and 15 PV) were included in the analysis of clinical outcome. All CV lesions included in the analysis were complications of prolonged catheterization. Eighty-nine percent of patients had end-stage renal disease and an AVF. Complications developed in 26% of patients with PV stents and in no patients with CV stents (P <.002). The mean follow-up period was 16 months. Sixty-two percent of patients required a reintervention for recurrent SVO. Only 32% of the interventions resulted in sustained symptomatic improvement. For CV stents, the primary patency rate was 85%, 27%, and 9% at 3, 12, and 24 months, respectively; the secondary patency rate was 91%, 71%, and 39% at 3, 12, and 24 months, respectively; and the clinical success rate was 94%, 94%, and 79%, at 3, 12, and 24 months, respectively. For PV stents, the primary patency rate was 73%, 17% and 17% at 3, 12, and 24 months, respectively; the secondary patency rate was 80%, 56%, and 35% at 3, 12, and 24 months, respectively; and the clinical success rate was 92%, 75%, and 42% at 3, 12 and 24 months, respectively. CONCLUSION: Stents provide a temporary benefit in most patients with central or peripheral upper-extremity SVO. Regular follow-up and reinterventions are required to maintain patency and achieve long-term clinical success. Stents used for CV lesions have higher clinical success rates than stents used for PV lesions. Patients with a reasonable life expectancy or who are unable to return for subsequent procedures should be considered for undergoing alternative therapy.

Autogenous arterial bypass grafts: durable patency and limb salvage in patients with inframalleolar occlusive disease and end-stage renal disease.

OBJECTIVE: The purposes of this study were to determine whether autogenous arterial grafts to distal pedal arteries improve the patency of grafts and limb salvage in patients with end-stage renal disease and nonhealing ischemic wounds and to better define the indications for autogenous arterial grafts. DESIGN: A review of consecutive patients with end-stage renal disease undergoing autogenous arterial grafts from 1994 through 1999 was carried out. The setting was a university hospital. All 11 patients with end-stage renal disease and nonhealing, ischemic wounds (stage IV SVS-ISCVS classification) undergoing autogenous arterial grafting from 1994 to 1999 were evaluated. Noninvasive studies confirmed inadequate perfusion pressures in all patients. Pre-bypass arteriography identified no major arteries patent at the level of the malleolus, with reconstitution of only a distal or branch pedal or plantar vessel less than 1 mm in diameter. Five patients with patent tibial vessels to just above the ankle underwent bypass surgery with autogenous arterial grafts alone. Six patients also had proximal occlusive disease that required grafts longer than the autogenous arterial grafts; in each of these six patients, an autogenous vein graft proximal to the autogenous arterial graft was placed through use of a composite technique. Inflow was from the common femoral artery in one patient, the popliteal artery in five patients, and a tibial artery in five patients. Outflow was to the medial plantar artery in five patients, the distal dorsalis pedis artery in three patients, the lateral plantar artery in two patients, and the superficial arch in one patient. The conduit was the subscapular artery in four patients, the deep inferior epigastric artery in four patients, the superficial inferior epigastric artery in two patients, and the radial artery in one patient. The main outcome measures were assisted primary graft patency and functional limb salvage rate. RESULTS: Follow-up ranged from 6 to 63 months (mean, 20 months); graft patency was determined by means of duplex scanning. All 11 patients are alive, and nine grafts are patent, including three after revision for graft stenosis. Assisted primary patency was 82% at 3 years. All nine patients with patent grafts remained ambulatory and had healed wounds or limited forefoot amputations. CONCLUSION: Autogenous arterial grafts were effective in treating limb-threatening ischemia in patients with end-stage renal disease and inframalleolar arterial insufficiency. Graft patency and limb salvage rates were higher than those reported for autogenous vein graft in these patients. Autogenous arterial grafting may therefore prove to be an effective alternative to autogenous vein grafting in selected patients.

Management of ischemic heel ulceration and gangrene: An evaluation of factors associated with successful healing.

OBJECTIVE: The objective of this study was to determine the effectiveness of treatment of nonhealing heel ulcers and gangrene and to define those variables that are associated with success. METHODS: A multi-institutional review was undertaken at four university or university-affiliated hospitals of all patients with wounds of the heel and arterial insufficiency, which was defined as absent pedal pulses and a decreased ankle/brachial index (ABI). Risk factors, hemodynamic parameters, and arteriographic findings were statistically analyzed to determine their effect on wound healing. Life-table analysis was used to assess graft patency and wound healing. RESULTS: Ninety-one patients (57 men, 34 women) were treated for heel wounds that did not heal for 1 to 12 months (62% of nonhealing wounds, 3 months or longer). The mean preoperative ABI was 0.51, and 31% of wounds were infected. Of the patients, 55% had impaired renal function (Cr > 1.5), with 24% undergoing dialysis, 70% had diabetes, and 64% smoked cigarettes. Treatment was topical wound care for all patients and operative wound débridement in 50%. Infrainguinal bypass was performed for 81 patients, 4 had inflow procedures, 3 had superficial femoral artery percutaneous transluminal angioplasty, and 3 had primary below-knee amputation. Postoperatively, 85% of patients had in-line flow to the foot with at least a single patent vessel, 66% had a pedal pulse, and the mean ABI improved by 0.40, to 0.91. Follow-up ranged from 1 to 60 months (mean, 21 months), and 77 patients (85%) are currently alive. In 66 patients (73%), the wounds healed-all within 6 months (mean, 3 months). For 14 (16%) the wounds had not healed, and 11 patients (11%) underwent below-knee amputation. By life-table analysis, limb salvage was 86% at 3 years. During follow-up, 75 infrainguinal bypasses (91%) remained patent (3 secondarily) and 6 occluded, with primary assisted patency of 87% at 3 years. All wounds in patients with occluded grafts failed to heal. Variables found to be statistically significant in predicting healing included normal renal function (95% healed vs 55% nonhealed, P <.002), a palpable pedal pulse (85% healed vs 42%, P <.0015), a patent posterior tibial artery past the ankle (86% healed vs 57%, P <.02), and the number of patent tibial arteries after bypass to the ankle (P <.0001). Neither the ABI nor the presence of infection (defined as positive tissue cultures or the presence of osteomyelitis), diabetes, or other cardiovascular risk factors influenced the outcome. CONCLUSIONS: Complete wound healing of ischemic heel ulcers or gangrene may require up to 6 months, and short-term graft patency is of minimal benefit. Successful arterial reconstruction, especially a patent posterior tibial artery after bypass, is effective in treating most heel ulcers or gangrene. Patients with impaired renal function are at increased risk for failure of treatment, but their wounds may successfully heal and they should not be denied revascularization procedures.

Tourniquet occlusion technique for tibial artery reconstruction.

The pneumatic compression tourniquet for tibial artery reconstruction reduces the necessary dissection, decreasing the risk of arterial and venous injury. It provides effective control of side branches, often expedites the operation, and provides a bloodless operative field with elimination of the need for clamps or vessel loops and their risk of arterial injury. They are easy to use, readily available, and, when used after leg elevation and esmarch compression, very effective. Despite the theoretical risks of muscle injury, nerve damage, or reperfusion syndrome, complications are rare. Overall results with the tourniquet in all recent reports have been excellent, and it can greatly facilitate tibial artery bypass.

Effect of outflow level and maximum graft diameter on the velocity parameters of reversed vein bypass grafts.

OBJECTIVE: The objective of this study was to define a normal range of distal graft velocity (DGV) and peak systolic velocity (PSV) on the basis of outflow level and maximum graft diameter for infrainguinal reversed vein bypass grafting (RVG). METHODS: This study was designed as a prospective study of consecutive patients who underwent infrainguinal RVG from 1994 to 1997 in a university hospital and university-affiliated teaching hospital. All patients who underwent infrainguinal bypass grafting from 1994 to 1997 were placed in a prospective protocol with duplex scanning to better define the hemodynamics of normally functioning RVG. Graft revisions were performed for patients with velocity ratios of more than 2.5. One hundred twenty-one patients were entered into this protocol, and 114 were followed more than 3 months after RVG. Seven patients were excluded: five for death within 3 months, one for graft infection, and one for graft occlusion before the baseline duplex scanning. DGV and PSV were determined for each type of outflow (popliteal, crural, and pedal) and for ranges of maximum graft diameter. These then were correlated with subsequent graft occlusion or graft revision (graft failure). RESULTS: Grafts with larger diameters were associated with lower DGVs (P <.001), and more proximal outflow arteries were associated with higher DGVs (popliteal, 75 cm/s; crural, 50 cm/s; and pedal, 40 cm/s; P <.01). The mean PSVs were 150, 140, and 122 cm/s for popliteal, crural, and pedal grafts, respectively, but the difference was not statistically significant. The assisted primary patency rates for the grafts in this series were 99%, 92%, and 92% at 1, 2, and 3 years. CONCLUSION: Graft diameter and location of the distal anastomosis significantly affect the flow velocity in RVG. Other variables did not influence these parameters. Currently established criteria for arteriography or graft repair on the basis of graft velocity parameters may be improved if they can be modified depending on diameter and outflow.

An assessment of the current applicability of the EVT endovascular graft for treatment of patients with an infrarenal abdominal aortic aneurysm.

OBJECTIVE: To determine the percentage of elective abdominal aortic aneurysms (AAAs)/aortoiliac aneurysms that currently can be repaired with endovascular grafts (EVGs), the reasons for rejection of EVGs, and the future role of EVG in the treatment of AAA. METHODS: From January 1997 to May 1998, patients at three hospitals (a university hospital, a university-affiliated teaching hospital, and a Veterans Administration hospital with university faculty and residents) were evaluated for EVGs as part of a national clinical trial with grafts manufactured by Endovascular Technologies (EVT, Menlo Park, Calif). All patients at two hospitals and patients treated by the participating surgeons at the third hospital were screened for EVG. Patients with AAAs that were ruptured, symptomatic, or involved renal or mesenteric arteries and patients who declined treatment were excluded from the study. Evaluation included clinical examination, computed tomography scan, and selective arteriography. The decision to proceed with EVG was made by the vascular surgeon, with input and concurrence of medical personnel from a company with extensive experience in endograft repair. The main outcome measures were the determination of the percentage of elective AAAs currently being treated with an EVG and the reasons for exclusion of patients from EVG placement. RESULTS: A total of 162 patients underwent elective treatment of an AAA, 22 (14%) with an EVG (14 bifurcated, eight tube) and 140 (86%) with traditional resection. Indications for not proceeding with an EVG included insufficient proximal cuff in 29 patients (21%), distal common iliac aneurysm or insufficient distal iliac neck in 29 patients (21%), proximal neck too large for an EVG in 24 patients (17%), symptomatic iliac stenosis in 23 patients (16%), iliac stenosis precluding introducer passage in 17 patients (12%), patient preference in 11 patients (8%), and calcification, kink, or extensive thrombus involving the proximal neck precluding safe graft attachment in seven patients (5%). Of the 22 patients treated with an EVG, three were converted to open resection, because of iliac stenosis in two patients and premature stent deployment in one patient (initial technical success rate, 86%). CONCLUSION: Based on currently available technology, 80% of patients were not candidates for an EVG because of proximal calcification, short aortic or distal cuff, coexisting distal iliac aneurysm, and stenotic iliac disease. Even with the use of adjunctive procedures, most patients still require open repair. Significant changes in design will be necessary to apply these devices to most patients with an AAA.

Does stent placement improve the results of ineffective or complicated iliac artery angioplasty?

OBJECTIVE: This study was undertaken to determine the results and complications of stents placed for initially unsuccessful or complicated iliac percutaneous transluminal angioplasty (PTA), the effect of location (external iliac or common iliac) on outcome, and the influence of superficial femoral artery patency on benefit. DESIGN: From 1992 through 1997, 350 patients underwent iliac artery PTA at the authors' institutions. Of this group, 88 patients (88 arteries) had one or more stents placed after PTA (140 stents in total) for residual stenosis or pressure gradient (63 patients), iliac dissection (12 patients), long-segment occlusion (10 patients), or recurrent stenosis (3 patients). Thirty patients required the placement of more than one stent. The indications for PTA in these 88 patients were claudication (48 patients) and limb-threatening ischemia (40 patients). Forty-seven patients had stents placed in the common iliac, 29 patients had stents placed in the external iliac, and 12 patients had stents placed in both. Seventy-one arteries (81%) were stenotic, and 17 (19%) were occluded before PTA. Sixty-six arteries were treated by interventional radiologists, 15 by a vascular surgeon, and 7 jointly. MAIN OUTCOME MEASURE: Criteria for success included (1) increase of at least one clinical category of chronic limb ischemia from baseline or satisfactory wound healing, (2) maintenance of an ankle/brachial index increase of more than 0.10 above the preprocedure index, and (3) residual angiographic stenosis less than 25% and, for patients with pressure gradient measurements, a residual gradient less than 10 mm Hg. RESULTS: Stent placement was accomplished in all 88 patients with 16 (18%) major complications. Mean follow-up was 17 months (range, 3 to 48 months). By life-table analysis, success was 75% at 1 year, 62% at 2 years, and 57% at 3 years. No cardiovascular risk factor or independent variable was statistically significant in predicting success. There was no difference in success rates for common iliac or external iliac lesions. Superficial femoral artery patency did not correlate with outcome. CONCLUSIONS: Although stents can eliminate residual lesions and arterial dissection, these patients are likely to require adjuvant or subsequent procedures to attain clinical success. By controlling the PTA complication and treating the emergent problem, stents may allow for subsequent elective intervention.

Endovascular treatment of abdominal aortic aneurysms.

Abdominal aortic aneurysms (AAA) may now be treated by endovascular placement of an arterial graft. These grafts are inserted through the femoral artery and then secured to the aorta above and below the aneurysm. The procedure reduces the risk of many perioperative complications and reduces hospital costs and length of stay. Several FDA-approved clinical trials are currently in progress with a variety of different devices. None is available for general use at this time. Overall, more than 800 grafts have now been placed, with a primary success rate of greater than 80%. Several complications have been reported, but the incidence of complications has generally decreased as proficiency has improved. The most troublesome problem has been leak of blood around the graft with continued risk of aneurysm rupture; therefore, follow-up CT scans and clinical examinations are mandatory to allow for appropriate treatment. Future modifications of current devices and techniques for delivery can be expected to reduce the incidence of currently identified problems. Endovascular grafting for AAA offers important potential advantages over conventional repair and may become increasingly important in the management of patients who have an abdominal aortic aneurysm.

Revision of reversed infrainguinal bypass grafts without preoperative arteriography.

PURPOSE: To determine whether graft revision on the basis of a duplex scan alone without an arteriogram is effective in identifying graft stenosis and allowing for repair to preserve bypass graft patency. METHODS: From 1994 to 1997, all patients in whom infrainguinal grafts were placed at a University-affiliated teaching hospital were entered into a prospective protocol using duplex scanning to detect stenotic lesions. Studies were performed after the operation, at 1 month, at 3 months, and every 3 months thereafter. All grafts were composed of reversed autogenous vein and were placed subcutaneously to allow for easier monitoring and correction. Patients who had failing grafts underwent operative correction without preoperative arteriography. RESULTS: During this interval, 48 lesions in 31 grafts were repaired. The indication for repair was a velocity ratio greater than 2.5 in all patients and greater than 3.0 for 43 lesions. Forty-four lesions had a peak systolic velocity greater than 250 cm/sec. Twenty-nine lesions reduced the distal graft velocity to less than 45 cm/sec. Sixteen lesions involved the proximal anastomosis, 26 the body of the graft, three the distal anastomosis, two involved inflow arteries, and one affected the outflow vessel. Repair included patch angioplasty for 39 lesions, resection with interposition graft for five, a proximal jump graft for three, and a distal extension graft for one. The severity and location of the stenosis was confirmed at operation in all cases. Twenty-eight of the 31 patients (90%) are currently alive, and follow-up on these patients has ranged from 5 to 36 months (mean, 19 months). Twenty-nine of the 31 grafts (94%) remained patent, with a 92% patency rate by life table analysis at 3 years. Follow-up duplex scans found improvement in the ankle-brachial index (mean increase, 0.33) and distal graft velocity (mean increase, 43 cm/sec) in all patients. After repair, 27 patients had a distal graft velocity greater than 45 cm/sec and no patient had a velocity ratio greater than 1.5. Complications included wound infection in two patients and bleeding that required reoperation in one. All symptomatic patients had clinical improvement, and none required early reexploration for residual stenosis. CONCLUSIONS: Graft repair may be safely performed on the basis of duplex scanning alone with preservation of bypass patency and correction of hemodynamic deterioration. Duplex scanning can detect inflow or outflow disease in addition to intrinsic graft stenoses and can identify sequential lesions, eliminating the need for, expense of, and risk of arteriography.

Spontaneous dissection of the internal carotid artery: a nineteen-year clinical experience.

PURPOSE: This article reviews our experience with internal carotid artery dissection (ICAD), evaluates the usefulness of Duplex scanning in diagnosis, provides current recommendations for treatment, and better defines long-term prognosis. METHODS: The records from 1976 to 1995 of 24 patients who had 28 ICAD were reviewed. All diagnoses were confirmed by arteriography. Presenting symptoms, diagnostic tests, clinical management, and outcome were examined. RESULTS: Nine patients had visual symptoms or headache, 10 had transient focal neurologic symptoms (TIA), and five had stroke. Five of the 19 who had visual symptoms or TIA had a stroke before the diagnosis of ICAD. Seventeen patients who had 19 ICAD underwent a Duplex scan at the time of presentation. Duplex scan identified 18 arterial abnormalities consistent with ICAD (sensitivity, 95%). Three patients died from stroke during the initial hospitalization. Of the 21 who survived, 12 were treated with anticoagulation therapy, six with aspirin, and three with aspirin and anticoagulation therapy. None of the 21 patients had a subsequent stroke. Six patients subsequently had an operation for residual occlusive disease or aneurysm. The mean duration of follow-up was 9.3 years. Two patients developed contralateral ICAD. During follow-up, 19 arteries were studied with Duplex scan, and seven had no residual evidence of ICAD. CONCLUSIONS: Patients who have ICAD often have prodromal symptoms before stroke. If diagnosed early, treatment with anticoagulation may prevent stroke. Duplex scans are accurate for defining carotid abnormalities consistent with ICAD and for indicating the need for arteriography. Patients should undergo a follow-up Duplex scan to identify contralateral ICAD.

Should percutaneous transluminal angioplasty be recommended for treatment of infrageniculate popliteal artery or tibioperoneal trunk stenosis?

PURPOSE: The purpose of this study was to determine the effectiveness of percutaneous transluminal angioplasty (PTA) for treatment of patients with localized stenosis of the infrageniculate popliteal artery and tibio-peroneal trunk (IGPA). METHODS: The records of 25 patients undergoing IGPA PTA from 1983 to 1993 were reviewed. Patients underwent follow-up with clinical examinations, ankle-brachial indexes, Duplex scanning, and arteriography. Demographic variables and cardiovascular risk factors were analyzed and correlated with outcome. RESULTS: Mean follow-up was 44 months. With life-table analysis, clinical and hemodynamic success was 59%, 32%, and 20% at 1, 2, and 3 years, respectively. Average time to recurrence was 17 months. Sixteen patients required a subsequent procedure; two had only repeat PTA, six had repeat PTA followed by arterial bypass, and eight had bypass alone. The mean additional benefit of repeat PTA was 8 months. Eleven of the 14 patients treated with bypass became symptom-free with patent grafts at a mean follow-up of 52 months. No risk factor was statistically significant in predicting success of IGPA PTA. CONCLUSIONS: IGPA PTA is an expensive temporizing measure with a high rate of recurrence requiring subsequent intervention. The procedure should be restricted to patients with limited life expectancy or contraindications to operation.

Treatment of recurrent femoral or popliteal artery stenosis after percutaneous transluminal angioplasty.

PURPOSE: This study was undertaken to compare repeat percutaneous transluminal angioplasty (rPTA), arterial reconstruction, and noninvasive therapy for treatment of patients with recurrent stenosis after PTA of the superficial femoral or popliteal artery. METHODS: From 1983 to 1993, 93 patients were treated for recurrent femoropopliteal stenosis. Indication for treatment was claudication in 72 patients, rest pain in 9, and ischemic ulcer in 12. Thirty-six patients (38%) were treated with arterial bypass, 35 (38%) with rPTA, and 22 (24%) with exercise and medication. Patients were monitored with clinical examination, ankle-brachial indexes, and duplex scanning. Follow-up ranged from 6 to 110 months (mean 42 months). RESULTS: With life-table analysis, the clinical and hemodynamic success of patients treated with rPTA was 41% at 1 year, 20% at 2 years, and 11% at 3 years. For patients treated with arterial bypass, the primary graft patency rate was 84%, 72%, and 72% at 1, 2, and 3 years, respectively. The secondary graft patency rate was 94%, 88%, and 88% at the same intervals. All patients with patent grafts were symptom free. All 22 patients treated with noninvasive therapy continued to have symptoms, but none required amputation during follow-up (range 6 to 108 months). Overall, patients with claudication did better than those treated for rest pain or an ischemic lesion after either rPTA or arterial bypass, but no other variable was statistically significant in predicting outcome. CONCLUSIONS: This study finds that arterial bypass is safe and more effective than rPTA in treating patients with recurrent stenosis. Preoperative evaluation is unable to select patients likely to benefit from rPTA. Repeat PTA should be reserved for patients with limited life expectancy or contraindications to operation.

The influence of diabetes mellitus on the risk of abdominal aortic surgery.

Risk factors and postoperative complications of 153 diabetics (DM) who underwent an abdominal aortic operation for occlusive disease or an intact aneurysm from 1964 through June, 1988 were compared with 970 nondiabetics (nonDM) who underwent similar operations during the same time period. Heart disease, hypertension, cerebrovascular disease, and renal insufficiency were more prevalent in diabetics. Postoperatively, DM had a statistically significant increase in the incidence of myocardial infarction (DM 5.2%, nonDM 2.1%, P = .0434) and wound infection (DM 2.6%, nonDM 0.6%, P = .0359). The incidence of renal failure (DM 1.3%, nonDM 1.0%), stroke (DM 2.0%, nonDM 0.6%), and death (DM 3.9%, nonDM 2.9%) was higher in diabetics, but the differences were not statistically significant (P = NS). Operative mortality was greater for patients operated on for aneurysm (DM 5.3%, nonDM 3.2%) than for patients operated for occlusive disease (DM 3.3% versus nonDM 2.7%). Diabetics treated with insulin or oral agents had a higher complication rate than diabetics treated with diet alone or nondiabetics (insulin 13.0%, oral 13.4%, diet 4.2%, nonDM 8.6%). This study finds that diabetic patients can undergo an abdominal aortic operation with operative mortality comparable to that of nondiabetics. Diabetics have more postoperative complications than nondiabetics, but only myocardial infarction and wound infection are of statistical significance. Diabetics treated with insulin or oral agents have more complications than do diabetics treated by diet alone or nondiabetics.

Tourniquet occlusion technique for tibial artery reconstruction.

PURPOSE: Vascular clamps, vessel loops, and intraluminal occluding devices used to control tibial and pedal vessels can be injurious and may fail to occlude heavily calcified arteries. In an effort to prevent injury to these small arteries, we have investigated the safety and efficacy of thigh pneumatic tourniquet occlusion for distal vascular control during infrapopliteal reconstruction. METHODS: During an 18-month period, 88 tibial or pedal arterial reconstructions were performed on 80 patients (mean age 75 years) by the tourniquet technique. Data regarding indications for operation, preoperative evaluation, intraoperative findings, surgical technique, and early outcome were recorded prospectively. RESULTS: Sixty percent of patients were diabetic: 36% insulin dependent and 24% non-insulin dependent. The indications for operation were claudication in 6 (7%), ischemic ulcer in 24 (27%), rest pain in 25 (28%), and gangrene in 33 (38%) patients. Thirty-five percent of operations followed failed ipsilateral infrainguinal reconstructions. The peroneal artery was the target vessel in 38%, anterior tibial in 26%, posterior tibial in 23%, tibioperoneal trunk in 9%, and inframalleolar vessels in 4% of cases. Preoperative analog waveforms and ankle-brachial indexes were used to classify the tibial arteries as compliant, 49%; relatively noncompressible, 30%; and absolutely noncompressible, 9%. Twelve percent had no Doppler flow at the ankle level. At operation 36 of the target arteries (41%) had mural calcification. Tourniquet pressures of 200 to 400 mm Hg (mode 250 mm Hg) were applied from 13 to 55 minutes (mean 27.1 +/- 9.1 minutes). All patients were given systemic anticoagulants. In 19 limbs (22%) the tourniquet was used to occlude a patent superficial femoral artery above the proximal (inflow) anastomosis to either the superficial femoral artery (8%), the above-knee popliteal artery (5%), or the below-knee popliteal artery (9%). Hemostasis was adequate in all cases and no alternative occlusive devices were required. There were no significant complications attributable to the use of the pneumatic tourniquet. CONCLUSION: Tourniquet occlusion simplifies the infrapopliteal dissection, lessens operating time, improves visualization of the distal anastomosis, and removes the potential for arterial injury to the target vessel. Arterial calcification and noncompressible tibial arteries do not contraindicate the use of thigh tourniquet occlusion. This technique is preferred for all patients undergoing tibial or pedal artery reconstruction.