Percutaneous transluminal revascularization for renal artery stenosis: Veterans Affairs Puget Sound Health Care System experience.

PURPOSE: The safety and efficacy of percutaneous transluminal intervention for renal artery stenosis is improving. This study evaluates the immediate and long-term anatomic and functional outcomes of percutaneous transluminal angioplasty and stenting for atherosclerotic renal artery stenosis in a Veterans Affairs population. METHODS: We performed a retrospective analysis of records from patients who underwent renal artery angioplasty with or without stenting at the Veterans Affairs Puget Sound Health Care System between January 1990 and June 1999. Indications for intervention included hypertension (78%) and rising serum creatinine (78%). Seventy-six patients (74 men, average age of 67 years, range 42-83 years) underwent 88 attempted interventions. Seventy-two percent of contralateral kidneys had significant disease (47% had a >60% stenosis; 16% were nonfunctioning or absent). RESULTS: Of the 88 planned interventions, 86 were successfully performed with placement of 46 stents (52%). Technical success (defined by <30% residual stenosis) was achieved in 78 vessels (89%). The procedure-related complication rate was 5%. Patient mortality by life table analysis was 49% at 5 years. Assisted primary patency rate at 5 years was 100%. Primary and secondary restenosis rates were 37% +/- 8% and 31% +/- 8% at 5 years, respectively. Sixty-eight percent of patients treated for hypertension demonstrated clinical benefit (improved or cured hypertension). This clinical benefit was maintained in 52% of the patients at 5 years, as measured by life table analysis. Serum creatinine was lowered or maintained in 88% of the patients, but this clinical benefit was only maintained in 25% of patients at 5 years. CONCLUSIONS: Transluminal intervention for clinically symptomatic atherosclerotic renal artery stenosis is technically successful and safe. There are excellent assisted-patency and low restenosis rates. There is immediate clinical benefit for most patients, as evidenced by improved control of hypertension and preservation of renal function. However, within 5 years the benefit is not maintained for either hypertension (50%) or renal function (20%). Therefore, although technically successful, functional outcomes after endoluminal intervention are not maintained in the long term.

Vascular access survival and incidence of revisions: a comparison of prosthetic grafts, simple autogenous fistulas, and venous transposition fistulas from the United States Renal Data System Dialysis Morbidity and Mortality Study.

OBJECTIVE: The study's aim was to evaluate access patency and incidence of revisions in patients initiating hemodialysis and to determine differences in access performance by type of access among patient subgroups. METHODS: The study used data from the United States Renal Data System Dialysis Morbidity and Mortality Study Wave 2, which contained a random sample of dialysis patients initiating dialysis in 1996 and early 1997. Failures and revisions were evaluated among 2247 newly placed hemodialysis accesses by using Cox proportional hazards regression model and Poisson regression. Primary and secondary patency rates were estimated using the Kaplan-Meier method. RESULTS: Fifteen hundred seventy-four prosthetic grafts, 492 simple autogenous fistulas, and 181 venous transposition fistulas were available for evaluation. Prosthetic grafts had a 41% greater risk of primary failure compared with simple fistulas (relative risk, 1.41; 95% CI, 1.22-1.64; P < .001) and a 91% higher incidence of revision (relative risk, 1.91; 95% CI, 1.60-2.28; P <.001). At 2 years, autogenous fistulas demonstrated superior primary patency (39.8% versus 24.6%, P < .001) and equivalent secondary patency (64.3% versus 59.5%, P = .24) compared with prosthetic grafts. When compared with simple fistulas, vein transpositions demonstrated equivalent secondary patency at 2 years (61.5% versus 64.3%, P = .43) but inferior primary patency (27.7% versus 39.8%, P = .008) and had a 32% increased incidence of revision (P = .04). Autogenous fistulas had superior primary patency compared with prosthetic grafts in all patient subgroups except for patients with previously failed access. Vein transpositions showed the greatest benefit in terms of patency and incidence of revision in women and in patients with previously failed access. CONCLUSIONS: The preferential placement of autogenous fistulas may increase primary patency and decrease the incidence of revisions. Vein transpositions had similar secondary patency compared with simple fistulas, but required more revisions. The greatest benefit of a vein transposition fistula was seen in women and in patients with a history of access failure.

Trends in peripheral vascular procedures in the Veterans Health Administration, 1989-1998.

OBJECTIVE: To assess trends in peripheral vascular procedures performed in Veterans Health Administration (VHA) facilities. METHODS: All discharges with peripheral vascular procedures recorded for 1989-1998 were analyzed. The VHA user population was used to calculate age-specific rates. Trends were evaluated using frequency tables and Poisson regression. RESULTS: The VHA had 55,916 discharges with peripheral vascular procedures performed almost exclusively in men. Indications included peripheral vascular disease (53.7%), gangrene (19.3%), surgical complications (13.3%), and ulcers and infection (9.6%). The VHA age-specific rates were higher than US population rates for persons 45 to 64 years, similar for those 65 to 74 years, and lower for those 75 years and older. The age-specific rates declined slightly over the 10 years of observation, with the greatest decline noted in men age 45 to 65. CONCLUSION: The VHA provides almost 8% of all US peripheral vascular procedures in males. The VHA age-specific rates differ from the US rates with a shift to younger patients. The rates decreased for all age groups between 1989-1998.

Survival following lower-limb amputation in a veteran population.

GOAL: We sought to describe the common demographic and comorbid conditions that affect survival following nontraumatic amputation. METHODS: Veterans Administration hospital discharge records for 1992 were linked with death records. The most proximal level during the first hospitalization in 1992 was used for analysis. Demographic information (age, race) and comorbid diagnosis (cardiovascular, cerebrovascular, and renal disease) were used for Kaplan-Meier curves to describe survival following amputation. MAIN OUTCOME MEASURE: Death. RESULTS: Mortality risk increased with advanced age, more proximal amputation level, and renal and cardiovascular disease, and decreased for African Americans. No increased risk for persons with diabetes was noted in the first year following amputation but the risk increased thereafter. A higher risk of mortality in the first year was noted for renal disease, cardiovascular disease, and proximal amputation level. CONCLUSION: Survival following lower-limb amputation is impaired by advancing age, cardiovascular and renal disease, and proximal amputation level. Also, a small survival advantage is seen for African Americans and those with diabetes.

Assessment of a policy to reduce placement of prosthetic hemodialysis access.

BACKGROUND: The aim of this study was to evaluate the determinants of access patency and revision, including the effects of reducing the placement of prosthetic hemodialysis access. METHODS: A retrospective cohort study of all hemodialysis accesses placed at the Veteran's Administration Puget Sound Health Care System between 1992 and 1999 was conducted. A policy was instituted in 1996 that maximized the use of autogenous hemodialysis access. The impacts of the policy change, demographics, and comorbid factors on access type and patency, were examined. Primary and secondary patency rates were examined using the Kaplan--Meier method, and factors associated with failure and revision were examined using Cox proportional hazard models and Poisson regression. RESULTS: During the study, 104 accesses (61 prosthetic grafts and 43 autogenous fistulas) were placed prior to 1996, and 118 (31 prosthetic grafts and 87 autogenous fistulas) were placed after 1996. There was a significant increase in autogenous fistulas placed after 1996 (87 out of 118) compared with before 1996 (43 out of 104, P < 0.001). At one year, autogenous fistulas demonstrated superior primary patency (56 vs. 36%, P = 0.001) and secondary patency (72 vs. 58%, P = 0.003) compared with prosthetic grafts. After adjustment for age, race, side of access placement, and history of prior access placement, patients with a prosthetic graft were estimated to experience a 78% increase in the risk of primary access failure when compared with similar patients having an autogenous access [adjusted relative risk (aRR) = 1.78, 95% CI 1.21--2.62, P = 0.003)]. Similarly, the adjusted relative risk of secondary access failure for comparing prosthetic grafts with autogenous fistulas was estimated to be 2.21 (95% CI 1.38--3.54, P = 0.001). The adjusted risk of access revision was 2.89-fold higher for prosthetic grafts than for autogenous fistulas (95% CI 1.88--4.44, P < 0.001). CONCLUSIONS: Autogenous conduits demonstrated superior performance when compared with prosthetic grafts in terms of primary and secondary patency and number of revisions. A policy emphasizing the preferential placement of autogenous fistulas over prosthetic grafts may result in improved patency and a reduction in the number of procedures required to maintain dialysis access patency.

Intraoperative superficial femoral artery balloon angioplasty and popliteal to distal bypass graft: an option for combined open and endovascular treatment of diabetic gangrene.

PURPOSE: The purpose of this study was to evaluate the results of combining intraoperative balloon angioplasty (IBA) of the superficial femoral artery (SFA) with distal bypass graft originating from the popliteal artery as a method of lower extremity revascularization in diabetic patients with gangrene. METHODS: Among 380 infrainguinal bypass grafts performed over a 6-year period, there were 110 reversed saphenous vein bypass grafts to the tibial or pedal arteries to treat diabetic patients with gangrene. Diffuse infrainguinal disease was treated with femoral-distal bypass graft (long; n = 46). Popliteal-distal bypass graft was performed when the inflow femoral artery was not significantly diseased (short; n = 52). Focal SFA stenosis and severe infrageniculate disease were treated with combined IBA of the SFA and distal bypass graft originating from the popliteal artery (combined; n = 12). Follow-up was performed with duplex scan surveillance of both the bypass graft and IBA sites. Treatment groups were compared with life-table analysis. RESULTS: There were no perioperative graft failures or amputations. The perioperative mortality rate was 1% (1 of 110). The 2-year primary patency rates were similar in the three groups: 72% in the long bypass graft group, 82% in the short bypass graft group, and 76% in the combined group (P =.8, log-rank test). SFA IBA sites developed recurrent stenosis in two patients, at 7 and 48 months; both were detected with surveillance and treated with percutaneous transluminal balloon angioplasty. The overall 5-year rate of primary patency was 63%, secondary patency was 78%, limb salvage was 81%, and survival was 35%. There were no significant differences among the three treatment groups with respect to these outcomes. CONCLUSION: Results with the combined procedure were similar to those achieved with either femoral-distal bypass graft or popliteal-distal bypass graft without SFA IBA. These data suggest that IBA of the inflow SFA may be combined with popliteal to distal bypass graft and that this technique is a reasonable alternative to longer, femoral-origin bypass graft in selected diabetic patients with gangrene.

Identification of factors predictive of lower extremity vein graft thrombosis.

OBJECTIVE: The objective of this study was to assess the prognostic value of hemodynamic parameters measured with duplex ultrasound scan, together with other important graft and patient characteristics, in predicting lower extremity vein graft thrombosis. METHODS: A total of 165 lower extremity vein grafts were entered prospectively into a postoperative duplex ultrasound scan surveillance program with examinations performed at 1, 2, 3, 4, 6, 9, 12, 18, and 24 months, and annually thereafter. Duplex scan-derived blood flow velocity measurements were recorded at 1562 patient visits over 7 years. Graft patency was determined after each visit, and an analysis of factors predictive of vein graft thrombosis was performed with Poisson regression. RESULTS: Thirty-two episodes of first-time graft thrombosis occurred, 23 of which were permanent. One-, 3-, and 5-year secondary graft patency rates were 90%, 86%, and 79%, respectively. In multivariate analyses, duplex scan velocity measurements predictive of lower extremity graft thrombosis included the maximum velocity ratio (Vr) in association with a graft stenosis and the mean graft peak systolic velocity (MGV) within nonstenotic portions of the body of the graft. The incidence of graft thrombosis among grafts without inflow/outflow stenoses, with Vr less than 3.5, and with MGV 50 cm/s or more, was 2.9% per year. Incidence rates were considerably higher among grafts with a of Vr of 3.5 or more (incidence rate ratio = 7.0; 95% CI, 3.4-14.6) or an MGV less than 50 cm/s (incidence rate ratio = 6.5; 95% CI, 3.3-13.1). In grafts without identifiable inflow, outflow, or graft stenoses, there was no association between MGV and the risk of graft thrombosis. CONCLUSION: Duplex scan velocity measurements are valid predictors of impending graft thrombosis. A Vr of 3.5 or more and an MGV less than 50 cm/s are the best predictive measures. Repair of correctable graft lesions with a Vr of 3.5 or more, or inflow, outflow, or graft lesions associated with an MGV less than 50 cm/s are recommended. Grafts without detectable inflow, outflow, or graft stenoses, regardless of MGV, may be safely followed.

Deep venous thrombosis and superficial venous reflux.

OBJECTIVE: Although superficial venous reflux is an important determinant of post-thrombotic skin changes, the origin of this reflux is unknown. The purpose of this study was to evaluate the frequency and etiologic mechanisms of superficial venous reflux after acute deep venous thrombosis (DVT). METHODS: Patients with a documented acute lower extremity DVT were asked to return for serial venous duplex ultrasound examinations at 1 day, 1 week, 1 month, every 3 months for the first year, and every year thereafter. Reflux in the greater saphenous vein (GSV) and lesser saphenous vein (LSV) was assessed by standing distal pneumatic cuff deflation. RESULTS: Sixty-six patients with a DVT in 69 lower extremities were followed up for a mean of 48 (SD +/- 32) months. Initial thrombosis of the GSV was noted in 15 limbs (21.7%). At 8 years, the cumulative incidence of GSV reflux was 77.1% (SE +/- 0.11) in DVT limbs with GSV involvement, 28.9% (+/- 0.09%) in DVT limbs without GSV thrombosis, and 14.8% (+/- 0.05) in uninvolved contralateral limbs (P <.0001). For LSV reflux, the cumulative incidence in DVT limbs was 23.1% (+/- 0.06%) in comparison with 10% (+/- 0.06%) in uninvolved limbs (P =.06). In comparison with uninvolved contralateral limbs, the relative risk of GSV reflux for DVT limbs with and without GSV thrombosis was 8.7 (P <.001) and 1.4 (P =.5), respectively. The relative risk of LSV reflux in thrombosed extremities compared with uninvolved extremities was 3.2 (P =.07). Despite these observations, the fraction of observed GSV reflux that could be attributable to superficial thrombosis was only 49%. CONCLUSIONS: Superficial venous thrombosis frequently accompanies DVT and is associated with development of superficial reflux in most limbs. However, a substantial proportion of observed reflux is not directly associated with thrombosis and develops at a rate equivalent to that in uninvolved limbs.

Trends in lower limb amputation in the Veterans Health Administration, 1989-1998.

OBJECTIVE: To assess trends in lower limb amputation performed in Veterans Health Administration (VHA) facilities. METHODS: All lower limb amputations recorded in the Patient Treatment File for 1989-1998 were analyzed using the hospital discharge as the unit of analysis. Age-specific rates were calculated using the VHA user-population as the denominator. Frequency tables and linear, logistic, and Poisson regression were used respectively to assess trends in amputation numbers, reoperation rates, and age-specific amputation rates. RESULTS: Between 1989-1998, there were 60,324 discharges with amputation in VHA facilities. Over 99.9% of these were in men and constitute 10 percent of all US male amputations. The major indications were diabetes (62.9%) and peripheral vascular disease alone (23.6%). The age-specific rates of major amputation in the VHA are higher than US rates of major amputation. VHA rates of major and minor amputation declined an average of 5% each year, while the number of diabetes-associated amputations remained the same. CONCLUSION: The number and age-specific rates of amputations decreased over 10 years despite an increase in the number of veterans using VHA care.

Full-thickness grafting of acute eyelid burns should not be considered taboo.

Split-thickness skin grafts are commonly used for the treatment of acute eyelid burns; in fact, this is dogma for the upper lid. Ectropion, corneal exposure, and repeated grafting are common sequelae, almost the rule. It was hypothesized that for acute eyelid burns, the use of full-thickness skin grafts, which contract less than split-thickness skin grafts, would result in a lower incidence of ectropion with less corneal exposure and fewer recurrences. The records of all patients (n = 18) who underwent primary skin grafting of acutely burned eyelids (n = 50) between 1985 and 1995 were analyzed retrospectively. There were 10 patients who received full-thickness skin grafts (12 upper lids, 8 lower lids) and 8 patients who received split-thickness skin grafts (15 upper lids, 15 lower lids). Three of 10 patients (30 percent) who received full-thickness skin grafts and 7 of 8 patients (88 percent) who received split-thickness skin grafts developed ectropion and required reconstruction of the lids (p = 0.02). No articles were found substantiating the concept that only split-thickness grafts be used for acute eyelid burns. The treatment of acute eyelid burns with full-thickness rather than split-thickness skin grafts results in less ectropion and fewer reconstructive procedures. It should no longer be considered taboo and should be carried out whenever possible and appropriate.

Venous thrombus stability during acute phase of therapy.

The purpose of this study was to use serial venous duplex scans to document the status of deep venous thrombi during the early phase of therapy for acute, deep-vein thrombosis (DVT). A total of 71 consecutive participants treated for a first episode of acute DVT were monitored for new venous thrombosis using serial venous duplex scans. An average of 4.6 duplex scans were performed per patient (range, three to seven) during the 3-week study period. The cumulative incidence of contiguous/non-contiguous extension of the DVT at 3 weeks was 26% (95% CI = 14% to 38%). Nine of the 15 (60%) occurrences were asymptomatic. None of the classical risk factors for DVT was significantly associated with the development of new thrombi. The fraction of time during which the level of anticoagulation was considered 'adequate' (international normalized ratio > or =2.0 and/or heparin concentration > or =0.2 IU/ml) was inversely associated with the risk of extension/new thrombi (p = 0.01, Cox proportional hazards analysis). It was concluded that: (1) the frequency of contiguous/non-contiguous extension of venous thrombosis detectable during the first 3 weeks of therapy was higher than previously reported; (2) the majority of the occurrences were asymptomatic; and (3) the risk of developing this complication was inversely associated with the level of anticoagulation achieved.

Inhibition of the transcriptional activator protein nuclear factor kappaB prevents hemodynamic instability associated with the whole-body inflammatory response syndrome.

BACKGROUND: The transcription factor nuclear factor kappaB mediates the expression of a number of inflammatory genes involved in the whole-body inflammatory response to injury. We and others have found that dithiocarbamates specifically inhibit nuclear factor kappaB-mediated transcriptional activation in vitro. OBJECTIVE: We hypothesized that inhibition of nuclear factor kappaB with dithiocarbamate treatment in vivo would attenuate interleukin 1 alpha-mediated hypotension in a rabbit model of systemic inflammation. METHODS: New Zealand White rabbits were anesthetized and cannulated for continuous hemodynamic monitoring during 240 minutes. Rabbits were treated intravenously with either phosphate-buffered saline solution or 15 mg/kg of a dithiocarbamate, either pyrrolidine dithiocarbamate or proline dithiocarbamate, 60 minutes before the intravenous infusion of 5 micrograms/kg interleukin 1 alpha. Nuclear factor kappaB activation was evaluated by electrophoretic gel mobility shift assay of whole-tissue homogenates. RESULTS: Infusion of interleukin 1 alpha resulted in significant decreases in mean arterial pressure and systemic vascular resistance, both of which were prevented by treatment with dithiocarbamate. Pyrrolidine dithiocarbamate induced a significant metabolic acidosis, whereas proline dithiocarbamate did not. Nuclear factor kappaB-binding activity was increased within heart, lung, and liver tissue 4 hours after interleukin 1 alpha infusion. Treatment with dithiocarbamate resulted in decreased nuclear factor kappaB activation in lung and liver tissue with respect to that in control animals. CONCLUSIONS: These results demonstrate that nuclear factor kappaB is systemically activated during whole-body inflammation and that inhibition of nuclear factor kappaB in vivo attenuates interleukin 1 alpha-induced hypotension. Nuclear factor kappaB thus represents a potential therapeutic target in the treatment of hemodynamic instability associated with the whole-body inflammatory response.

Blood pressure, antihypertensive medication, and atherosclerotic renal artery stenosis.

The relationship between atherosclerotic renal artery stenosis (ARAS) and blood pressure control remains poorly understood. Duplex ultrasonography is a noninvasive method for detecting and grading ARAS. The purpose of this study was to characterize the relationship between the degree of ARAS, levels of blood pressure, and control of blood pressure with antihypertensive medication. A cross-sectional analysis was performed on 139 patients with ARAS. All patients had at least one diseased renal artery by duplex ultrasound. Renal arteries were classified as normal, less than 60% stenosis, or 60% or greater (high-grade) stenosis. Data regarding blood pressure, coexisting risk factors, and medications were collected. The extent of ARAS was significantly associated with progressive elevation of the systolic blood pressure, whereas the diastolic component was elevated in the case of unilateral high-grade stenosis: no high-grade stenoses, 153 +/- 22/81 +/- 10 mm Hg; unilateral high-grade stenosis, 162 +/- 22/86 +/- 9 mm Hg; and bilateral high-grade stenoses, 174 +/- 27/82 +/- 9 mm Hg (P = 0.002 systolic; P = 0.02 diastolic). Eighty-two percent of the patients were taking known antihypertensive medications. Angiotensin-converting enzyme inhibitor (ACEI) usage versus nonusage was associated with a significantly lower systolic (157 +/- 27 v 169 +/- 22 mm Hg; P = 0.03) and diastolic (79 +/- 9 v 85 +/- 9 mm Hg; P = 0.001) blood pressure. The effect of ACEI usage was observed in patients with high-grade ARAS. None of the other classes of antihypertensive medications were associated with significantly lower blood pressure. In patients with ARAS, blood pressure levels were correlated with the severity of renal artery disease. Patients taking ACEIs had significantly lower blood pressures, and the effect of ACEI usage was strongest among patients with unilateral ARAS.

Prospective study of atherosclerotic disease progression in the renal artery.

BACKGROUND: The aim of this study was to determine the incidence of and the risk factors associated with progression of renal artery disease in individuals with atherosclerotic renal artery stenosis (ARAS). METHODS AND RESULTS: Subjects with >/=1 ARAS were monitored with serial renal artery duplex scans. A total of 295 kidneys in 170 patients were monitored for a mean of 33 months. Overall, the cumulative incidence of ARAS progression was 35% at 3 years and 51% at 5 years. The 3-year cumulative incidence of renal artery disease progression stratified by baseline disease classification was 18%, 28%, and 49% for renal arteries initially classified as normal, <60% stenosis, and >/=60% stenosis, respectively (P=0.03, log-rank test). There were only 9 renal artery occlusions during the study, all of which occurred in renal arteries having >/=60% stenosis at the examination before the detection of occlusion. A stepwise Cox proportional hazards model included 4 baseline factors that were significantly associated with the risk of renal artery disease progression during follow-up: systolic blood pressure >/=160 mm Hg (relative risk [RR]=2.1; 95% CI, 1.2 to 3.5), diabetes mellitus (RR=2.0; 95% CI, 1.2 to 3.3), and high-grade (>60% stenosis or occlusion) disease in either the ipsilateral (RR=1.9; 95% CI, 1.2 to 3.0) or contralateral (RR=1.7; 95% CI, 1.0 to 2.8) renal artery. CONCLUSIONS: Although renal artery disease progression is a frequent occurrence, progression to total renal artery occlusion is not. The risk of renal artery disease progression is highest among individuals with preexisting high-grade stenosis in either renal artery, elevated systolic blood pressure, and diabetes mellitus.

Determinants of chronic venous disease after acute deep venous thrombosis.

PURPOSE: The purpose of this investigation was to evaluate the relationship between the presenting features of an acute deep venous thrombosis (DVT), the subsequent natural history of the thrombus, and the ultimate outcome as defined according to the Society for Vascular Surgery and the North American Chapter of the International Society for Cardiovascular Surgery reporting standards in venous disease. METHODS: Patients with an acute DVT were followed with serial clinical and ultrasound examinations. Thrombus extent within 7 venous segments was scored retrospectively according to the reporting standards (scores ranged from 0 to 3), and segmental reflux was scored as present (1) or not present (0). The initial and final thrombus scores, the rates of recanalization and rethrombosis, and the total reflux scores were then calculated from these grading scales and related to ultimate chronic venous disease (CVD) classification. RESULTS: Sixty-eight patients with an acute DVT in 73 limbs were followed for 18 to 110 months (mean, 55 +/- 26 months). At the completion of the follow-up period, 20 extremities (27%) were asymptomatic (class 0), 13 (18%) had pain or prominent superficial veins (class 1), 25 (34%) had manifested edema (class 3), 13 (18%) had developed hyperpigmentation (class 4), and 2 (3%) had developed ulceration (class 5). In a univariate analysis, CVD classification was correlated with the reflux score (P =.003) but not with the initial or final thrombus score or with the rate of recanalization or rethrombosis. In a multivariate model of features documented at presentation, only the tibial thrombosis score was a significant predictor of CVD classification (R2 =.06). Outcome was better predicted (R2 =.29) with a model that included variables defined during follow-up the final reflux score, the final popliteal score, and the rate of recanalization. CONCLUSION: The ability to predict the severity of CVD after an acute DVT is currently limited, although the natural history appears more important than the presenting features of the event. The extent of reflux, the presence of persistent popliteal obstruction, and the rate of recanalization are related to ultimate CVD classification, but other determinants remain to be identified.

Carotid and lower extremity arterial disease in patients with renal artery atherosclerosis.

BACKGROUND: Atherosclerotic lesions of the carotid and lower extremity arteries may be associated with renal artery stenosis and influence the management of patients with renal artery disease. OBJECTIVE: To document the prevalence and clinical features of carotid and lower extremity arterial disease in patients with renal artery atherosclerosis. METHODS: An analysis of baseline data on 149 patients enrolled in a prospective natural history study of atherosclerotic renal artery stenosis. Patients with at least 1 abnormal renal artery by duplex scanning were eligible. Carotid artery disease was evaluated by duplex scanning, and ankle/brachial indices were used to assess the lower extremity arteries. Disease at each of the 3 arterial sites was classified as mild, moderate, or severe based on the extent of involvement on both sides. Serum urea nitrogen, creatinine, and lipid levels were also measured. RESULTS: Severe renal, carotid, or lower extremity arterial disease was present in 44%, 19%, and 21% of the patients, respectively. There was a trend for patients with increasing degrees of renal artery disease to have increasing degrees of carotid and lower extremity arterial disease. The prevalence of severe carotid artery disease increased from 7% in the mild renal artery group to 28% in the severe renal artery group. Clinical factors that were most predictive of severe disease were elevated apolipoprotein B levels for the renal arteries, high serum urea nitrogen or creatinine levels for the carotid arteries, and smoking for the lower extremity arteries. CONCLUSIONS: There was a strong association between severe renal artery atherosclerosis and severe carotid artery disease. Patients with renal artery disease also had a high prevalence of lower extremity arterial disease. In this patient population, screening for lower extremity arterial disease can be reserved for those with signs or symptoms of peripheral ischemia. Noninvasive carotid screening is justified in patients with renal artery disease to detect asymptomatic lesions that require either immediate surgical treatment or serial follow-up for disease progression.

Risk of atrophy in kidneys with atherosclerotic renal artery stenosis.

The goal of this study was to determine the incidence of and risk factors for renal atrophy among kidneys with atherosclerotic renal artery stenosis (ARAS). Participants with at least one ARAS were followed prospectively with duplex scans performed every six months. Renal atrophy was defined as a reduction in renal length of greater than 1 cm. A total of 204 kidneys in 122 subjects were followed for a mean of 33 months. The two-year cumulative incidence (CI) of renal atrophy was 5.5%, 11.7%, and 20.8% in kidneys with a baseline renal artery disease classification of normal, <60% stenosis, and > or = 60% stenosis, respectively (P = 0.009, log rank test). Other baseline factors associated with a high risk of renal atrophy included a systolic blood pressure > 180 mm Hg (2-year CL = 35%, P = 0.01), a renal artery peak systolic velocity > 400 cm/second (2-year CI = 32%, P = 0.02), and a renal cortical end diastolic velocity < or = 5 cm/second (2-year CI = 29%, P = 0.046). The number of kidneys demonstrating atrophy per participant was correlated with elevations in the serum creatinine concentration (P = 0.03). In patients with ARAS, there is a significant risk of renal atrophy among kidneys exposed to elevated systolic blood pressure and among those with high-grade ARAS and low renal cortical blood flow velocity as assessed by renal duplex scanning. The occurrence of renal atrophy is well-correlated with changes in the serum creatinine concentration.

Clinical evidence of contralateral renal parenchymal injury in patients with unilateral atherosclerotic renal artery stenosis.

It has been postulated that the kidney contralateral to a significant renal artery stenosis may be at risk for accelerated arteriolar nephrosclerosis. Duplex ultrasound is capable of detecting and classifying renal artery stenosis and examining parenchymal flow. Renal flow patterns are a reflection of resistance, which increases with parenchymal pathology. One-hundred fifty-one patients with atherosclerotic renal artery stenosis (ARAS) were prospectively studied with duplex ultrasonography. Renal arteries were classified as normal, <60% stenosis, > or =60% stenosis, or occluded. The renal artery end-diastolic ratio (EDR) (end-diastolic velocity/peak systolic velocity) was measured. EDR decreases as resistance to flow increases. There were 81 patients with a unilateral > or =60% ARAS. The EDR was significantly lower in the kidney contralateral to the > or =60% ARAS (0.27 +/- 0.08 versus 0.30 +/- 0.08; p = 0.001, paired t-test). The absolute difference in EDR was even more pronounced in the subgroup of 15 diabetic patients with a > or =60% ARAS (0.22 +/- 0.08 versus 0.27 +/- 0.08; p = 0.004). This study offers clinical evidence that a unilateral hemodynamically significant ARAS is associated with the development of arteriolar nephrosclerosis in the contralateral kidney. These results have important implications on blood pressure control, renal function, and response to renal revascularization in this patient population.

The epidemiology of vascular trauma.

The study of blood vessel injury has largely focused on diagnosis, treatment, and the outcome of treatment. Although the epidemiology of trauma in general has been extensively studied and reported, the specific epidemiology of vascular injury has not. This report includes a general discussion of the incidence of and risk factors associated with injury to blood vessels. Vascular injury epidemiology has been studied in three different settings: military conflicts, large urban centers, and to a lesser extent, in rural areas. There has been an increase in the incidence of vascular injury in the United States over the past four decades that has paralleled the increase in assault with firearms, motor vehicle crashes, and invasive medical procedures. Mortality and the utilization of medical resources is higher among patients with vascular injury than among trauma patients without blood vessel injuries. There are well-documented differences in the demographics of blood vessel injury in urban versus rural settings. The mechanisms of injury (penetrating, blunt, iatrogenic) are associated with characteristic anatomic patterns of vascular and other organ system injury.

Early outcome after isolated calf vein thrombosis.

PURPOSE: The clinical significance of isolated calf vein thrombosis (CVT), particularly with respect to development of the postthrombotic syndrome, remains controversial. The purpose of this study was to define the early natural history of CVT in relation to persistent lower extremity symptoms, propagation, recanalization, and the development of valvular incompetence. METHODS: Over a 116-month period, 499 patients with acute deep venous thrombosis (DVT) were referred to our research laboratory, of whom 58 (12%) had thrombosis confined to the calf veins of at least one extremity. The lower extremities of 268 patients (29 with isolated CVT) were followed-up clinically and with duplex ultrasonography at intervals of 1 day, 7 days, 1 month, every 3 months for the first year, and yearly thereafter. RESULTS: Seventy percent of extremities with CVT were symptomatic at presentation. Although the prevalence of clinical signs and symptoms decreased to 29% by 1 month, 23% of patients had persistent pain, edema, or both at 12 months. In contrast, 9% of uninvolved extremities contralateral to a CVT and 54% of extremities with proximal DVT remained symptomatic at 1 year (p = 0.004). Recanalization proceeded rapidly such that the mean thrombus load was reduced by 50% at 1 month and to zero at 1 year. The prevalence of valvular incompetence progressively increased such that reflux was present in 24% of extremities at 1 year. Although its investigation was not a primary goal of this study, pulmonary embolism was diagnosed at presentation and during follow-up in 11% and 3% of patients, respectively. CONCLUSIONS: The natural history of CVT is complicated by persistent symptoms and the development of valvular incompetence in approximately one-quarter of patients. This potential for persistent lower extremity symptoms should be considered in evaluating the clinical relevance of isolated calf vein DVT.