Solid state, pulsed-wave 355 nm UV laser atherectomy debulking in the treatment of infrainguinal peripheral arterial disease: The Pathfinder Registry.

BACKGROUND: Atherectomy is an important option for debulking atherosclerotic plaque from diseased arteries in patients with infrainguinal arterial disease. Laser atherectomy uses a high-powered laser to remove the plaque from the arteries to restore blood flow. AIMS: The Pathfinder multicenter registry was initiated to evaluate the safety and efficacy of the 355 nm laser atherectomy system in a real-world setting for the treatment of de novo, re-stenotic and in-stent restenosis (ISR) lesions in infrainguinal arteries of patients with peripheral artery disease (PAD). METHODS: The study was a prospective, single-arm, multicenter, open-label registry study for patients treated with the 355 nm laser system. Clinical and lesion characteristics, procedural safety and efficacy data, and baseline, 6-, and 12-month outcomes data, including Ankle Brachial Index (ABI), Rutherford class, and Walking Impairment Questionnaires (WIQ), were collected. The primary efficacy endpoint was the achievement of ≤30% final residual stenosis at the index lesion postatherectomy and adjunctive therapy evaluated by an angiographic Core Lab. The primary safety endpoint was the percentage of subjects who did not experience periprocedural major adverse events (PPMAEs) before discharge. RESULTS: One hundred and two subjects with 121 lesions treated with the 355 nm laser device at 10 centers were included in the analysis. Mean age was 68.4 ± 10.21 years, 61.8% of subjects were male, 44.6% had critical limb ischemia (CLI), and 47.3% had tibial lesions. The mean residual stenosis at the end of the procedure was 24.4 ± 15.5 with 69 lesions (69.0%) achieving technical procedural success (<30% stenosis); similar rates were observed for subjects with ISR (25.5 ± 14.9), chronic total occlusion (CTO) (28.1 ± 17.0), and severe calcification (36.5 ± 21.6) lesions. Mean ABI, Rutherford, and WIQ scores were improved at both 6 and 12 months. Ninety-seven of 102 subjects (95.1%) met the primary safety endpoint of not experiencing a PPMAE before discharge. CONCLUSIONS: The initial data from the Pathfinder Registry demonstrates the 355 nm laser system is safe and effective in a real-world setting for performing atherectomy in patients with infrainguinal PAD.

Workflow and Patient Satisfaction in Treating Peripheral Arterial Disease in the Office-Based Setting.

Contemporary concepts in health-care reform promote a shift in the provision of care away from hospitals in favor of the more cost-effective and efficient use of outpatient facilities including ambulatory surgery centers and office-based procedure centers particularly in the care of cardiovascular disease. This article reviews the experience of patients and specialists in caring for patients with peripheral arterial disease in an office-based care setting.

Initial experience with the ambulatory management of acute iliofemoral deep vein thrombosis with May-Thurner syndrome with percutaneous mechanical thrombectomy, angioplasty and stenting.

OBJECTIVE: Patients undergoing intervention for acute iliofemoral deep vein thrombosis (IFDVT) with May-Thurner syndrome (MTS) typically require inpatient (IP) hospitalization for initial treatment with anticoagulation and management with pharmacomechanical thrombectomy. Direct oral anticoagulants and percutaneous mechanical thrombectomy (PMT) devices offer the opportunity for outpatient (OP) management. We describe our approach with these patients. METHODS: Patients receiving intervention for acute IFDVT from January 2020 through October 2022 were retrospectively reviewed. Patients undergoing unilateral thrombectomy, venous angioplasty, and stenting for IFDVT with MTS comprised the study population and were divided into two groups: (1) patients admitted to the hospital and treated as IPs and (2) patients who underwent therapy as OPs. The two groups were compared regarding demographics, risk factors, procedural success, complications, and follow-up. RESULTS: A total of 92 patients were treated for IFDVT with thrombectomy, angioplasty, and stenting of whom 58 comprised the IP group and 34 the OP group. All 92 patients underwent PMT using the Inari ClotTriever (Inari Medical), intravascular ultrasound, angioplasty, and stenting with 100% technical success. Three patients in the IP group required adjuvant thrombolysis. There was no difference in primary patency of the treated IFDVT segment at 12 months between the two groups (IP, 73.5%; OP, 86.7%; P = .21, log-rank test). CONCLUSIONS: Patients with acute IFDVT and MTS deemed appropriate for thrombectomy and iliac revascularization can be managed with initiation of ambulatory direct oral anticoagulant therapy and subsequent return for ambulatory PMT, angioplasty, and stenting. This approach avoids the expense of IP care and allows for effective use of resources at a time when staffing and supply chain shortages have led to inefficiencies in the provision of IP care for nonemergent conditions.

The Use of Re-Entry Devices Through Pedal Arterial Access in the Management of Chronic Limb-Threatening Ischemia.

Infra-inguinal arterial chronic total occlusions remain a challenging scenario for the endovascular practitioner. Retrograde access has quickly become an essential tool in approaching such lesions, increasing the chances of crossing success. When antegrade and retrograde access techniques fail in achieving lesion crossing, re-entry devices have proven to be useful. Their use is however, somewhat limited by the size of the sheaths required to accommodate their passage. As newer and slimmer profiled sheaths become available, the possibilities of interventions available from minimally invasive approaches increases. We present 2 complex arterial revascularization cases that required intravascular ultrasound-based re-entry devices utilizing a pedal retrograde access.

A case of leiomyosarcoma of the common femoral artery.

Leiomyosarcomas are rare malignant tumors of smooth muscle cell origin with those originating from blood vessels accounting for <1%. We report the unusual case of a leiomyosarcoma originating in the wall of the common femoral artery, highlighting the management decisions for vascular tumors and providing a brief literature review for these unusual malignancies.

Hybrid Approach with Angiography and Limited Open Exposure to Treat Type Ia Endoleaks after Endovascular Aortic Aneurysm Repair.

BACKGROUND: Type Ia endoleaks after endovascular aortic repair (EVAR) almost always mandate secondary percutaneous reinterventions. Several patients, however, will require conversion to open surgical repair with complete graft explant, which is associated with significant morbidity and mortality. We herein present 3 cases of hybrid surgical repair for type Ia endoleaks, using a limited open exposure for proximal stent graft edge revision to achieve graft preservation and effective aneurysm sac exclusion. METHODS: Angiography was used to confirm type Ia endoleak in 3 patients (2 males) who had previous EVAR between October 2017 and October 2019. Time to the endoleak after the index EVAR was immediate in 1 patient during repair of a ruptured aneurysm, 2 months in 1 patient and 2 years in 1 patient. The aorta was exposed through a limited transabdominal (n = 1) or retroperitoneal (n = 2) approach and circumferential aortic control was achieved below the renal arteries. A row of interrupted horizontal mattress sutures of 3-0 polypropylene reinforced with Teflon pledgets was placed along the aortic neck circumference. Multi-planar angiography was then repeated to verify the absence of sac filling and successful type Ia endoleak exclusion. Follow-up abdominal duplex was obtained for all 3 patients after discharge to monitor the stent graft and confirm endoleak resolution. Furthermore, there were no instances of acute renal failure. RESULTS: In the period of review, 77 patients underwent EVAR. In the 3 patients described, we were able to achieve complete aneurysm sac exclusion and stent graft preservation in all cases. Follow-up imaging was available on 2 patients at 4-6 weeks after surgery demonstrating sustained exclusion of the endoleak. Two patients died during follow-up: one from a myocardial infarction 7 weeks after surgery and one from metastatic lung cancer at 8 months after surgery. Follow up duplex imaging at one year on the single survivor demonstrated sac shrinkage and absence of endoleak. CONCLUSIONS: Type Ia endoleaks represent a significant source of morbidity and mortality after EVAR and typically require repair to avoid aneurysm rupture. Our use of limited proximal revision without explant provides an alternative approach to resolve the endoleaks while reducing the magnitude of physiological stress when compared to an open explant. It represents a feasible option for high-risk patients.

Distal Retrograde Access for Infrainguinal Arterial Chronic Total Occlusions: A Prospective, Single Center, Observational Study in the Office-Based Laboratory Setting.

OBJECTIVE: To assess the safety and efficacy of retrograde arterial recanalization of infrainguinal CTOs in the OBL setting. METHODS: Consecutive patients who underwent interventions for lower extremity CTOs in the OBL setting by a single vascular surgeon were evaluated (January 2013-November 2017). If antegrade crossing was not possible, then a retrograde distal approach was used. Patient characteristics, CTO location, procedural time, contrast, anticoagulation and radiation doses and costs were recorded. Post-procedural complications were documented on post-procedure day 1 and 10-14 days post procedure. Three groups were compared: group 1-antegrade approach for femoropopliteal CTOs; group 2-antegrade approach for tibial CTOs, and; group 3-retrograde approach for femoropopliteal and tibial CTOs. RESULTS: Two hundred and thirty-seven patients were studied. In 39 (16.5%), the lesions could not be crossed. A successful antegrade approach was used in 185 of them, of which 69% (group 1, n = 128) patients had femoropopliteal CTOs and 31% (group 2, n = 57) had tibial CTOs. Fourteen patients (5.9%, group 3) were treated by retrograde distal approach. Group 3 patients received higher contrast doses than groups 1 and 2 (p = 0.01). However, patients in groups 1 and 2 received similar contrast doses. Group 3 patients had the highest operative time and treatment costs followed by group 1 and then group 2 (p = 0.01). Three femoral pseudoaneurysms were noted in group 1, and 2 in group 2. No complications were seen in group 3. CONCLUSIONS: Although the operative times, costs, radiation and contrast dose are higher with retrograde arterial access, it represents a safe and effective method for the crossing of CTO infrainguinal lesions in an ambulatory venue.

Analysis of endovascular therapy for femoropopliteal disease with the Supera stent.

BACKGROUND: The structural limitations of currently available laser-cut nitinol stents in the highly diseased arterial system of the lower extremity are well described. These devices are frequently used in long-segment occlusions, at the adductor hiatus, and across the knee into the popliteal artery and tibial-peroneal trunk despite concerns related to the high mobility of the knee joint and the potential for external stent compression, fractures, and occlusion. The Supera stent (Abbott Vascular, Santa Clara, Calif) was developed to provide superior radial strength, fracture resistance, and flexibility compared with laser-cut nitinol stents. This study represents the initial U.S. experience in the management of lower extremity artery atherosclerotic disease with the Supera interwoven wire stent. METHODS: Patients undergoing stent implantation in the 20-month period after the 2008 Food and Drug Administration clearance were included. Medical records, radiographic imaging, and procedural data were examined. Procedural angiograms were classified according to TransAtlantic Inter-Society Consensus criteria. Patency and limb loss rates were calculated using Kaplan-Meier analysis. RESULTS: There were 305 stents implanted in 147 patients. Clinical follow-up was a mean of 12.7 months (range, 0.2-33.7 months), and radiologic follow-up was a mean of 8.4 months (range, 0.2-26.8 months). Most patients had critical limb ischemia, with tissue loss (38.1%) or rest pain (28.6%) as the indication for intervention. Of the 147 patients, 75 (51.02%) underwent a concomitant adjunctive procedure in the treated extremity. Primary, assisted primary, and secondary patency rates at 12 months by duplex ultrasound imaging were 89.8%, 91.2%, and 93.2%, respectively, by Kaplan-Meier estimates, with a mean lesion length of 184.5 ± 131.80 mm and mean stented length of 197.5 ± 113.65 mm. Seventeen patients experienced an event requiring successful reintervention in the stented segment (13 for type I or II restenosis; four for type III). There were eight major amputations, with five of those eight having a patent stent at the time of limb sacrifice. The overall mortality was 11.6% during the study period. Knee radiography was performed in 47 patients with devices extending into the popliteal and tibial-peroneal segment, and no stent fractures were identified. CONCLUSIONS: Stenting of the superficial femoral and popliteal arteries using the Supera stent system appears to be safe and effective. The interwoven stent design may better serve areas under extreme mechanical stress. Our results with this population of highly diseased patients including very long lesion lengths are consistent with outcomes of other publications reporting the use of this device.

Preliminary results of the initial United States experience with the Supera woven nitinol stent in the popliteal artery.

BACKGROUND: Popliteal artery stenting is not routinely performed due to concerns related to the high mobility of the knee joint and the potential for external stent compression, fractures, and occlusion. Open bypass is traditionally considered the gold standard for popliteal artery atherosclerotic lesions. The Supera stent (IDEV Technologies Inc, Webster, Tex) was developed to provide superior radial strength, fracture resistance, and flexibility compared with laser-cut nitinol stents. This study represents the initial United States experience in the management of popliteal artery atherosclerotic disease with the Supera interwoven wire stent. METHODS: Patients undergoing stent implantation in the 20-month period after the 2008 Food and Drug Administration clearance were included. Medical records, radiographic imaging, and procedural data were examined. Procedural angiograms were classified according to Trans-Atlantic Inter-Society Consensus criteria. Patency and limb loss rates were calculated using Kaplan-Meier analysis. RESULTS: A total of 39 stents were placed in 34 patients due to isolated popliteal artery occlusive disease. Clinical follow-up was a mean of 12.7 months (range, 0.2-33.7 months), and radiologic follow-up was a mean of 8.4 months (range, 0-26.8 months). Most patients had critical limb ischemia (CLI), with tissue loss (38.2%) or rest pain (35.3%) as the indication for intervention. In 20 patients (58.8%), the most distal end of the stent(s) landed in the below-the-knee popliteal segment, 12 (35.3%) landed in the above-the-knee segment, and two (5.9%) landed precisely at the knee. Other than angioplasty and stenting, 47% of patients did not receive any adjuvant concomitant therapy in the treated leg. Two patients underwent concomitant atherectomy of the popliteal segment. Primary, primary assisted, and secondary patency rates by duplex ultrasound imaging were 79.2%, 88.1% and 93%, respectively, by Kaplan-Meier estimates, with a mean stented length of 12 cm. Six instances of stent occlusion were noted, and six patients were identified with hemodynamically significant in-stent stenosis. Three patients sustained limb loss (8.8%), two related to uncontrolled infections, and one due to perioperative ischemic complications (both with patent stents at the time of limb loss). The overall mortality was 8.8% during the study period. Knee roentgenography was performed in all but one patient, and no stent fractures were identified. CONCLUSIONS: Stenting of the popliteal artery using the Supera stent system appears to be safe and effective. The interwoven stent design may better serve areas under extreme mechanical stress. Our results with this highly diseased patient population justify a prospective trial in this subject.

Gram-negative groin sepsis treated with covered stents and systemic antibiotics.

Prosthetic graft infections are hazardous conditions. Those due to Gram-negative bacteria are particularly serious. When Gram-negative microorganisms are present, entire graft excision is recommended, with revascularization if needed, preferably with autogenous tissues or with prosthetic grafts via non-infected planes if autogenous options are not available. We herein report the case of a diabetic man with critical limb ischemia, who after lower-extremity revascularization with a prosthetic graft, developed an early graft infection due to Gram-negative and fungal organisms, and who was successfully treated with a covered stent placed across grossly infected tissues. A discussion on the pertinent literature is also offered.

Asymptomatic lower extremity acrocyanosis: report of two cases and review of the literature.

Vasospastic disorders affecting the lower extremities are unusual entities. Two cases of asymptomatic foot discoloration with lower extremity dependency are presented. In the first case, an elderly gentleman was admitted to the hospital with a contralateral foot infection. His physical exam revealed pulse examination within normal limits and his blood work failed to identify any known causes for vasospasm. His foot infection was successfully treated with sensitivity-directed antibiotics. The second case is that of a young man with a history of quadriplegia secondary to a remote diving accident, who presented with a three-month history of foot discoloration while sitting up in his wheelchair, which resolved with recumbent leg positioning. A review of the possible diagnoses for these patients' presentation is presented herein.

Vertebral artery aneurysms and cervical arteriovenous fistulae in patients with neurofibromatosis 1.

Vascular involvement in the setting of neurofibromatosis type 1(NF1) has been well described. However, the coexistence of NF1 with vertebral artery (VA) aneurysms and arteriovenous fistulae (AVFs) is a rare occurrence. A 60-year-old female with NF1 and other severe comorbidities presented with acute respiratory insufficiency caused by a ruptured large VA aneurysm and an associated AVF that required emergent intubation and eventual repair through endovascular techniques that resolved her symptoms. A detailed description of this case and a comprehensive review of the literature are also presented.

Coronary-subclavian steal: presentation and management: two case reports.

Subclavian stenosis is a highly prevalent and underrecognized clinical entity. In patients with a history of coronary artery bypass grafting utilizing a left internal mammary artery, subclavian artery stenosis can cause coronary-subclavian steal, leading to myocardial ischemia. Traditionally, this has been treated surgically with a vascular bypass operation. Two cases of coronary-subclavian steal syndrome are presented, 1 treated percutaneously with angioplasty and stent, and 1 treated with a combined endovascular-surgical procedure.

Renovascular hypertension.

Renal artery disease is the most common cause of potentially curable secondary hypertension, with atherosclerosis as the major cause of renal artery stenosis. Fibromuscular dysplasia is a less common cause of renal artery stenosis and is most frequently observed in premenopausal women. Renal artery stenosis is likely to be underappreciated and is more common in patients with other vascular disease (e.g., coronary or peripheral arterial disease). The diagnosis of renal artery stenosis requires a high clinical index of suspicion as well as an appropriate imaging strategy, with currently effective diagnostic modalities including magnetic resonance imaging, computed tomography and renal artery duplex ultrasonography. The current treatment of choice for atherosclerotic renal artery stenosis is balloon angioplasty and secondary stenting, whereas angioplasty alone is the treatment for renal artery stenosis secondary to fibromuscular dysplasia. Expected outcomes following revascularization include improved blood pressure control and possibly renal preservation. Ongoing studies will hopefully identify patient characteristics that will achieve the most benefit from percutaneous revascularization as well as the impact of percutaneous revascularization with drug-eluting stents and embolic protection devices.

Acute aortic syndromes: aortic dissections, penetrating aortic ulcers and intramural aortic hematomas.

Acute aortic syndromes, including dissections, intramural hematomas and penetrating aortic ulcers, are a catastrophic clinical entity that are relatively uncommon. A high index of clinical suspicion along with proper imaging modalities are critical in making a prompt and accurate diagnosis for immediate management and to improve survival of the patient.

Influence of type II endoleak volume on aneurysm wall pressure and distribution in an experimental model.

OBJECTIVE(S): We have previously shown that type II endoleak size is a predictor of aneurysm growth after aortic endografting. To better understand this observation, we investigated the influence of endoleak size on pressure transmitted to the aneurysm wall and its distribution within the aneurysm sac. METHODS: In an ex vivo model, an artificial aneurysm sac was incorporated within a mock circulation comprised of rubber tubing and a pulsatile pump. Three strain-gauge pressure transducers were placed in the aneurysm wall at different locations, including the site of maximum aneurysm diameter. The aneurysm was filled with either human aneurysm thrombus or dough that mimicked thrombus and simulated type II endoleaks of varying volumes (1 to 10 mL) were created. Aneurysm wall pressure (AWP) measurements were recorded at mean arterial pressures (MAPs) of 60, 80, and 100 mm Hg. Correlation coefficients ( r ) and analysis of variance were used to assess the relationship between endoleak volume and AWP. RESULTS: Increasing endoleak volume '3 cm 3 resulted in proportionally increased AWP at all levels of MAP and at all sites, with highest pressures recorded at the site of the maximum aneurysm diameter (r = 0.83 when MAP = 100 mm Hg; r = 0.85 when MAP = 80 mm Hg; r = 0.88 when MAP = 60 mm Hg; P < .001). AWP plateaued when the endoleak volume was >3 cm 3 . Pressure distribution within the sac was not uniform. Although the difference was within +/-10%, statistically significant higher AWPs were observed at the site of maximum aneurysm diameter (P <.001). AWP also correlated with MAP. CONCLUSIONS: Increasing type II endoleak volume results in proportionally higher AWP, which is greatest at the site of maximum aneurysm diameter. This study confirms the clinical observation that type II endoleak volume and MAP may be important predictors of aneurysm expansion. CLINICAL RELEVANCE: Our experimental model of a type II endoleak revealed that endoleak size is a significant factor that influences the magnitude of pressure transmission into the aneurysm wall. Increasing volume of the endoleak nidus was associated with proportionally higher aneurysm sac pressures. This mechanism may, in fact, account for the increased risk of aneurysm expansion observed in our clinical experience, thereby suggesting the need for more aggressive surveillance and possibly earlier intervention for patients with larger endoleaks.

Endovascular exclusion of saphenous vein graft aneurysms complicating abdominal aortic aneurysm repair--a case report.

A 64-year-old man was referred for vascular evaluation before renal transplantation for ischemic nephropathy. In the past he had undergone bilateral renal artery revascularizations using saphenous vein. At the time of transplant evaluation, he was found to have bilateral aneurysms of the saphenous veins used to bypass his renal artery stenoses. He underwent successful endovascular exclusion of the aneurysms with 2 endovascular AneuRx extension cuffs. This case highlights both the versatility of endovascular treatments as well as the importance of a comprehensive vascular examination.

Conservative vs. invasive treatment of aortocoronary saphenous vein graft aneurysms: Treatment algorithm based upon a large series.

BACKGROUND: The development of a saphenous vein graft aneurysm (SVGA) after coronary artery bypass graft surgery is a rare occurrence. There are approximately 60 cases reported in the literature, the majority being single case reports. There is no consensus on the treatment of SVGA. METHODS: Retrospective analysis of the patients treated with SVGA was performed at our institution. Demographic and co-morbidity data were acquired on the patients. Patients who underwent surgical treatment were compared to those treated conservatively with the primary outcome being survival time from diagnosis of the SVGA. RESULTS: Thirteen patients with 15 SVGA were identified. The average age at the time of the most recent coronary artery bypass grafting (CABG) was similar in the conservative and the surgically treated groups (55 vs. 56.5 years, respectively). The average number of grafts per patient at the most recent CABG was similar (3.83 vs. 4.0, respectively). The average time from CABG to diagnosis was similar in both the groups (12.6 vs. 15 years, respectively). The average survival from diagnosis was similar in both the groups (2.3 vs. 1.5 years, respectively, p>0.05). CONCLUSIONS: Early surgical treatment of SVGA does not provide longer short-term survival compared with conservative management. A treatment algorithm for SVGA based upon patient co-morbidities and aneurysm characteristics is proposed.

Distribution of sac pressure in an experimental aneurysm model after endovascular repair: the effect of endoleak types I and II.

PURPOSE: To study in an experimental aneurysm model the differential distribution of strain/pressure (S/P) on the aneurysm wall before and after endograft exclusion and in the presence of individual type I and type II endoleaks. METHODS: Two tapered elliptical Gore-Tex patches were sutured to an anterior and posterior longitudinal arteriotomy of an 8-mm Gore-Tex tube graft, thus creating a fusiform aneurysm. Two S/P transducers were placed at the proximal sac adjacent to the proximal neck, 2 at the site of the widest sac diameter, and 2 at the sac adjacent to the distal neck. The aneurysm, which was connected to a pulsatile pump system, was excluded using a 10-mm endograft. Type I and type II endoleaks were created and tested individually. S/P measurements were obtained at systemic systolic pressures (BP) of 80, 110, and 150 mmHg. Thrombosis of the sac contents was induced by injection of thrombin and calcium in the sac. Angiography was used to verify presence or absence of flow in the sac. RESULTS: Aneurysm exclusion resulted in significant S/P reductions at all 3 BP levels versus prior to exclusion (p<0.05). Thrombus in the sac did not alter S/P in the excluded sac (p>0.05 for all 3 BP levels). In the presence of a proximal type I endoleak, S/P distribution was not uniform, and S/P at the proximal neck was close to S/P prior to exclusion (p>0.05 no graft versus type I endoleak for all 3 BP levels). This was also true in the presence of thrombus. With a type II endoleak, S/P was more evenly distributed and was not significantly elevated compared to the pressure without an endoleak (p>0.05, graft versus type II endoleak for all 3 BP levels). Thrombus had no effect on intrasac S/P with a type II endoleak. Intrasac S/P was significantly higher in the presence of a type I endoleak compared to a type II endoleak when BP=150 mmHg (p=0.008). CONCLUSIONS: Endovascular exclusion of an aneurysm results in uniform S/P reduction in the aneurysm sac. Type I endoleak, but not type II endoleak, results in significantly higher S/P in an area of the sac adjacent to the proximal neck. Thrombus does not result in significantly different S/P distribution in the aneurysm sac.

Histopathological study of renal transplant artery stenosis: role of rejection and cold ischaemia time in the pathogenesis of intimal hyperplasia in an arterial allograft.

INTRODUCTION: Intimal hyperplasia of renal allograft arteries is a cause of hypertension and graft loss and the predisposing factors are poorly understood. We performed a histopathological study focusing on cold ischaemia time and immunological factors and their effect on the donor artery. METHODS: Primary renal artery branches were obtained from patients undergoing transplant nephrectomy for chronic rejection. Non-transplant patients undergoing nephrectomy served as controls. Clinical information including immunosuppression and rejection episodes, cold ischaemia time and graft survival were collected from the patients' charts. Collagen, smooth muscle cells, T cells, macrophages, and neutrophils were quantified using immunohistochemistry. The intima to media ratio was also calculated using imaging software. Statistical analysis was performed using linear regression and the Mann-Whitney test with P < 0.05 significant. RESULTS: Nine transplant patients and five controls were included. All transplant patients received maximum immunosuppression according to clinical standards. The median number of acute rejection episodes was 1 (range 0-5). Cold ischaemia time was 24.3 +/- 9.6 h (mean +/- SD). Mean allograft longeviy was 87.4 +/- 72.9 months (mean +/- SD). The intima/media ratio in the transplant group was higher as compared with the control (P = 0.002). The same was true for intima collagen content (P = 0.001) and intima smooth muscle content (P = 0.036). Cold ischaemia time was 19.6 +/- 11.1 h (mean +/- SD) and did not correlate with intima/media ratio. Also the number of rejection episodes did not correlate with the intima/media ratio. CONCLUSION: Intimal hyperplasia in the allograft artery has a multifactorial aetiology. We were not able to establish an association between intimal hyperplasia and acute rejection episodes or length of cold ischaemia time. It appears that immunosuppression does not prevent the development of intimal hyperplasia.