Predictive value of noninvasively determined endothelial dysfunction for long-term cardiovascular events in patients with peripheral vascular disease

OBJECTIVES

The goal of this study was to prospectively examine the long-term predictive value of brachial-artery endothelial dysfunction for future cardiovascular events.

BACKGROUND

Brachial-artery endothelial function is impaired in individuals with atherosclerosis and coronary risk factors. The prospective relation between endothelial function determined by brachial-artery ultrasound and long-term cardiovascular risk is unknown.

METHODS

We examined brachial-artery endothelial function using ultrasound in 199 patients with peripheral arterial disease before elective vascular surgery. Patients were prospectively followed with an average follow-up of 1.2 years after surgery.

RESULTS

Thirty-five patients had an event during follow-up, including cardiac death (5 patients), myocardial infarction (17 patients), unstable angina (10 patients), or stroke (3 patients). Preoperative endothelium-dependent flow-mediated dilation (FMD) was significantly lower in patients with an event (4.4 +/- 2.8%) compared with those without an event (7.0 +/- 4.9%, p < 0.001), whereas endothelium-independent vasodilation to nitroglycerin was similar in both groups. In a Cox proportional-hazards model, independent predictors of events included age (p = 0.003), more invasive surgery (surgery other than carotid endarterectomy, p = 0.02), and impaired brachial-artery endothelial function (p = 0.002). Risk was approximately nine-fold higher in patients with FMD <8.1% (lower two tertiles) compared with those in the upper tertile (odds ratio 9.5; 95% confidence interval 2.3 to 40).

CONCLUSIONS

Impaired brachial-artery endothelial function independently predicts long-term cardiovascular events in patients with peripheral arterial disease. The findings suggest that noninvasive assessment of endothelial function using brachial-artery FMD may serve as a surrogate end point for cardiovascular risk.

Peripheral arterial disease in diabetic and nondiabetic patients: a comparison of severity and outcome

OBJECTIVE

The aim of this study was to quantify the distribution of peripheral arterial disease in the diabetic and nondiabetic population attending for angiography and to compare severity and outcome between both groups of patients.

RESEARCH DESIGN AND METHODS

Randomly selected lower-extremity angiograms were examined according to the Bollinger system. Patient demographics and medical history were recorded and case notes were examined to determine which patients later underwent a revascularization procedure or amputation and which patients had died.

RESULTS

A total of 136 arteriograms obtained between 1992 and 1996 were analyzed. The age (mean +/- SD) of the patients was 64.7 +/- 10.8 years. Diabetic patients (43%) and nondiabetic patients were of similar age (63.9 +/- 10.4 vs. 65.3 +/- 11.1 years, P = 0.43), with a similar history of smoking (81.0 vs. 76.9%, P = 0.26), ischemic heart disease (41.4 vs. 37.2%, P = 0.54), and hypercholesterolemia (24.4 vs. 30.8%, P = 0.48). However, there were a greater proportion of hypertensive patients in the diabetic group (63.8 vs. 39.7%, P = 0.006). Diabetic patients had greater severity of arterial disease in the profunda femoris and all arterial segments below the knee (P = 0.02). A greater number of amputations occurred in the diabetic group: diabetic patients were five times more likely to have an amputation (41.4 vs. 11.5%, odds ratio [OR] 5.4, P < 0.0001). Mortality was higher in the diabetic group (51.7 vs. 25.6%, OR 3.1, P = 0.002), and diabetic patients who died were younger at presentation than nondiabetic patients (64.7 +/- 11.4 vs. 71.1 +/- 8.7 years, P = 0.04).

CONCLUSIONS

In patients with peripheral arterial disease, diabetic patients have worse arterial disease and a poorer outcome than nondiabetic patients.

Results of PREVENT III: A multicenter, randomized trial of edifoligide for the prevention of vein graft failure in lower extremity bypass surgery

OBJECTIVE

The PREVENT III study was a prospective, randomized, double-blinded, multicenter phase III trial of a novel molecular therapy (edifoligide; E2F decoy) for the prevention of vein graft failure in patients undergoing infrainguinal revascularization for critical limb ischemia (CLI).

METHODS

From November 2001 through October 2003, 1404 patients with CLI were randomized to a single intraoperative ex vivo vein graft treatment with edifoligide or placebo. After surgery, patients underwent graft surveillance by duplex ultrasonography and were followed up for index graft and limb end points to 1 year. A blinded Clinical Events Classification committee reviewed all index graft end points. The primary study end point was the time to nontechnical index graft reintervention or major amputation due to index graft failure. Secondary end points included all-cause graft failure, clinically significant graft stenosis (>70% by angiography or severe stenosis by ultrasonography), amputation/reintervention-free survival, and nontechnical primary graft patency. Event rates were based on Kaplan-Meier estimates. Time-to-event end points were compared by using the log-rank test.

RESULTS

Demographics, comorbidities, and procedural details reflected a population with CLI and diffuse atherosclerosis. Tissue loss was the presenting symptom in 75% of patients. High-risk conduits were used in 24% of cases, including an alternative vein in 20% (15% spliced vein and 5% non-great saphenous vein) and 6% less than 3 mm in diameter; 14% of the cases were reoperative bypass grafts. Most (65%) grafts were placed to infrapopliteal targets. Perioperative (30-day) mortality occurred in 2.7% of patients. Major morbidity included myocardial infarction in 4.7% and early graft occlusion in 5.2% of patients. Ex vivo treatment with edifoligide was well tolerated. There was no significant difference between the treatment groups in the primary or secondary trial end points, primary graft patency, or limb salvage. A statistically significant improvement was observed in secondary graft patency (estimated Kaplan-Meier rates were 83% edifoligide and 78% placebo; P = .016) within 1 year. The reduction in secondary patency events was manifest within 30 days of surgery (the relative risk for a 30-day event for edifoligide was 0.45; 95% confidence interval, 0.27-0.76; P = .005). For the overall cohort at 1 year, the estimated Kaplan-Meier rate for survival was 84%, that for primary patency was 61%, that for primary assisted patency was 77%, that for secondary patency was 80%, and that for limb salvage was 88%.

CONCLUSIONS

In this prospective, randomized, placebo-controlled clinical trial, ex vivo treatment of lower extremity vein grafts with edifoligide did not confer protection from reintervention for graft failure.

Bypass versus Angioplasty in Severe Ischaemia of the Leg (BASIL) trial: An intention-to-treat analysis of amputation-free and overall survival in patients randomized to a bypass surgery-first or a balloon angioplasty-first revascularization strategy

BACKGROUND

A 2005 interim analysis of the Bypass versus Angioplasty in Severe Ischaemia of the Leg (BASIL) trial showed that in patients with severe lower limb ischemia (SLI; rest pain, ulceration, gangrene) due to infrainguinal disease, bypass surgery (BSX)-first and balloon angioplasty (BAP)-first revascularization strategies led to similar short-term clinical outcomes, although BSX was about one-third more expensive and morbidity was higher. We have monitored patients for a further 2.5 years and now report a final intention-to-treat (ITT) analysis of amputation-free survival (AFS) and overall survival (OS).

METHODS

Of 452 enrolled patients in 27 United Kingdom hospitals, 228 were randomized to a BSX-first and 224 to a BAP-first revascularization strategy. All patients were monitored for 3 years and more than half for >5 years.

RESULTS

At the end of follow-up, 250 patients were dead (56%), 168 (38%) were alive without amputation, and 30 (7%) were alive with amputation. Four were lost to follow-up. AFS and OS did not differ between randomized treatments during the follow-up. For those patients surviving 2 years from randomization, however, BSX-first revascularization was associated with a reduced hazard ratio (HR) for subsequent AFS of 0.85 (95% confidence interval [CI], 0.5-1.07; P = .108) and for subsequent OS of 0.61 (95% CI, 0.50-0.75; P = .009) in an adjusted, time-dependent Cox proportional hazards model. For those patients who survived for 2 years after randomization, initial randomization to a BSX-first revascularization strategy was associated with an increase in subsequent restricted mean overall survival of 7.3 months (95% CI, 1.2-13.4 months, P = .02) and an increase in restricted mean AFS of 5.9 months (95% CI, 0.2-12.0 months, P = .06) during the subsequent mean follow-up of 3.1 years (range, 1-5.7 years).

CONCLUSIONS

Overall, there was no significant difference in AFS or OS between the two strategies. However, for those patients who survived for at least 2 years after randomization, a BSX-first revascularization strategy was associated with a significant increase in subsequent OS and a trend towards improved AFS.

Bypass versus Angioplasty in Severe Ischaemia of the Leg (BASIL) trial: Analysis of amputation free and overall survival by treatment received

BACKGROUND

An intention-to-treat analysis of randomized Bypass versus Angioplasty in Severe Ischaemia of the Leg (BASIL) trial data showed that initial randomization to a bypass surgery (BSX)-first strategy was associated with improvements in subsequent overall survival (OS) and amputation-free survival (AFS) of about 7 and 6 months, respectively. We describe the nature and timing of first, crossover, and reinterventions and examine AFS and OS by first treatment received. We also compare vein with prosthetic BSX and transluminal with subintimal balloon angioplasty (BAP) and examine outcomes from BSX after failed BAP.

METHODS

We randomly assigned 452 patients with SLI due to infrainguinal disease in 27 United Kingdom hospitals to a BSX first (n = 228) or a BAP first (n = 224) revascularization strategy. All patients have been monitored for 3 years and more than half for >5 years. We prospectively collected data on every procedure, major amputation, and death.

RESULTS

Patients randomized to BAP were more likely to have their assigned treatment first (94% vs 85%, P = .01, chi(2)test). BAP had a higher immediate technical failure rate of 20% vs 2.6% (P = .01, chi(2)test). By 12 weeks after randomization 9 BAP (4%) vs 23 BSX (10%) patients had not undergone revascularization; 3 BAP (1.3%) vs 13 BSX (5.8%) had undergone the opposite treatment first; and 35 BAP (15.6%) and 2 (0.9%) BSX had received the assigned treatment and then undergone the opposite treatment. BSX distal anastomoses were divided approximately equally between the above and below knee popliteal and crural arteries; most originated from the common femoral artery. About 25% of the grafts were prosthetic and >90% of vein BSX used ipsilateral great saphenous vein. Most (80%) BAP patients underwent treatment of the SFA alone (38%) or combined with the popliteal artery (42%) and crural arteries (20%). Outcome of vein BSX was better for AFS (P = 0.003) but not OS (P = 0.38, log-rank tests) than prosthetic BSX. There were no differences in outcome between approximately equal numbers of transluminal and subintimal BAP. AFS (P = 0.006) but not OS (P = 0.06, log rank test) survival was significantly worse after BSX after failed BAP than after BSX as a first revascularization attempt.

CONCLUSIONS

BAP was associated with a significantly higher early failure rate than BSX. Most BAP patients ultimately required surgery. BSX outcomes after failed BAP are significantly worse than for BSX performed as a first revascularization attempt. BSX with vein offers the best long term AFS and OS and, overall, BAP appears superior to prosthetic BSX.

Epidemiology of lower extremity amputation in centres in Europe, North America and East Asia

BACKGROUND

This study was established to enable a comparison of lower extremity amputation incidence rates between different centres around the world.

METHODS

Ten centres, all with populations greater than 200 000, in Japan, Taiwan, Spain, Italy, North America and England collected data on all amputations done between July 1995 and June 1997. Patients were identified from at least two data sources (to allow checks on ascertainment); denominator populations were based on census figures.

RESULTS

The highest amputation rates were in the Navajo population (43.9 per 100 000 population per year for first major amputation in men) and the lowest in Madrid, Spain (2.8 per 100 000 per year). The incidence of amputation rose steeply with age; most amputations occurred in patients over 60 years. In most centres the incidence was higher in men than women and the incidence of major amputations was greater than that of minor amputations. Diabetes was associated with between 25 and 90 per cent of amputations.

CONCLUSION

Apart from the Navajo centre, differences in the known prevalence of diabetes could not account for the differences in overall incidence of amputation. Differences in the prevalence of peripheral vascular disease are likely to be important, but this and the role of other factors, including availability of health care, are worthy of further investigation.

The Timed "up and go" test: reliability and validity in persons with unilateral lower limb amputation

OBJECTIVE

To determine the interrater and intrarater reliability and the validity of the Timed "up and go" test as a measure for physical mobility in elderly patients with an amputation of the lower extremity.

DESIGN

To test interrater reliability, the test was performed for two observers at different times of the same day in an alternating order. To test intrarater reliability, the patients performed the test for one observer on two consecutive visits with an interval of 2 weeks. To test validity, the results of the Timed "up and go" test were compared with the results on the Sickness Impact Profile, 68-item version (SIP68), and the Groningen Activity Restriction Scale (GARS).

PATIENTS

Thirty-two patients, age 60 yrs or older, with unilateral transtibial or transfemoral amputation because of peripheral vascular disease.

RESULTS

The Timed "up and go" test showed good intrarater and interrater reliability (r = .93 and .96, respectively). A moderate relationship exists between the Timed "up and go" test and the GARS, a good relationship exists with the "physical subscales" of the SIP68, and there is no relationship with the "mental subscales" of the SIP68.

CONCLUSIONS

The Timed "up and go" test is a reliable instrument with adequate concurrent validity to measure the physical mobility of patients with an amputation of the lower extremity.

Trends, complications, and mortality in peripheral vascular surgery

BACKGROUND

The recent evolution in treatments for peripheral vascular disease has dated available mortality statistics for vascular intervention. Moreover, many of our current mortality statistics are derived from single-institution studies that are often not reflective of outcomes in general practice. To provide current and generalizable data regarding mortality and trends for peripheral vascular interventions, we examined two national data sets (Nationwide Inpatient Sample, 1998-2003, and National Hospital Discharge Survey, 1979-2003) and four states (New York, California, Florida, and New Jersey, 1998-2003).

METHODS

Four procedures--abdominal aortic aneurysm repair (nonruptured), lower extremity revascularization, amputation, and carotid revascularization--were selected by cross-referencing International Classification of Diseases, 9th Revision, diagnostic and procedural codes. For significance, the t test was used for continuous variables, the chi2 test was used for dichotomous variables, and the chi2 test was used for mortality trends.

RESULTS

From 1998 to 2003, there was a progressive decrease in the national per capita rate of amputations: 13.2% overall and 21.2% for major amputations (P < .0001). Nationally and regionally, mortality has only slightly declined. For lower extremity revascularization, after a sharp increase during the 1980s to 100,000 open procedures, the volume remained constant for 10 years and began to decline in 1998, reaching 70,000 cases in 2003. In contrast, since 1996, endovascular interventions have increased 40%. Mortality during the 1998 to 2003 period remained virtually stable at 1.5% to 2% for endovascular procedures and 3% to 4% for open procedures. The overall volume of abdominal aortic aneurysm repair has not changed substantially for the past 6 years; however, endovascular repair is now used for nearly half the cases (46.5% regional and 43.0% national). Mortality for open repair has not changed, remaining at approximately 5%, whereas for endovascular repair, mortality has declined from 2.6% in 2000 to less than 1.5% in 2003. After the rapid increase in open carotid revascularization in the early 1990s, the total volume has declined 5% nationally from 1998 to 2003. Regional data demonstrated an overall 12% reduction in carotid revascularization volume since 1998; this reduction was due to a 16% decline in open carotid revascularization. During this same period, the use of angioplasty-stent carotid revascularization doubled. Mortality for the open procedures is 0.5% and is significantly higher (2%-3%) for endovascular carotid revascularization. Stroke rates for endovascular carotid revascularization are also higher: 2.13% vs 1.28% for open procedures (P < .0001).

CONCLUSIONS

Dramatic shifts in the management of peripheral vascular disease have occurred together with an overall decline in mortality. There seems to be a significant mortality advantage for endovascular as compared with traditional surgery except for carotid endarterectomy. The increasing safety of vascular interventions should be considered when deciding which patients to treat but with the caveat that endovascular interventions are not always safer than open repair.

Treatment with Intramuscular Vascular Endothelial Growth Factor Gene Compared with Placebo for Patients with Diabetes Mellitus and Critical Limb Ischemia: A Double-Blind Randomized Trial

Despite advances in revascularization techniques, limb salvage and relief of pain cannot be achieved in many diabetic patients with diffuse peripheral vascular disease. Our objective was to determine the effect of intramuscular administration of phVEGF165 (vascular endothelial growth factor gene-carrying plasmid) on critical limb ischemia (CLI) compared with placebo (0.9% NaCl). A double-blind, placebo-controlled study was performed in 54 adult diabetic patients with CLI. The primary end point was the amputation rate at 100 days. Secondary end points were a 15% increase in pressure indices (ankle-to-brachial index and toe-to-brachial index), clinical improvement (skin, pain, and Quality of Life score), and safety. In patients (n=27) treated with placebo versus phVEGF165-treated patients (n=27) the following results were found: 6 amputations versus 3 (p=not significant [NS]); hemodynamic improvement in 1 versus 7 (p=0.05); improvement in skin ulcers, 0 versus 7 (p=0.01); decrease in pain, 2 versus 5 (p=NS); and overall, 3 versus 14 responding patients (p=0.003). No grade 3 or 4 adverse effects were seen in these patients. We conclude that this small, randomized gene therapy study failed to meet the primary objective of significant amputation reduction. However, significant and meaningful improvement was found in patients treated with a VEGF165-containing plasmid. There were no substantial adverse events.

Relationship between postoperative anemia and cardiac morbidity in high-risk vascular patients in the intensive care unit

OBJECTIVE

To determine if postoperative anemia is associated with postoperative myocardial ischemia and morbid cardiac events

DESIGN

Case control study.

SETTING

Postanesthesia care unit and surgical intensive care unit.

PATIENTS

A total of 27 high-risk patients undergoing infra-inguinal arterial bypass procedures.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

After informed consent, patients were continuously monitored by ambulatory electrocardiographic recorders from the evening before surgery up to 80 hrs during the postoperative period. Myocardial ischemia was defined as > or = 1 mm of horizontal or downsloping ST depression or > or = 2 mm ST segment elevation persisting for at least 60 secs on the ambulatory electrocardiogram. Morbid cardiac events were defined as: cardiac death, myocardial infarction, unstable angina, and ischemic pulmonary edema. Using a receiver operating characteristic curve, a hematocrit of 28% was determined to be the best threshold hematocrit value below which morbid cardiac events were most likely to occur. Statistical significance between hematocrit and cardiac outcome was determined by Fisher's exact test where appropriate. Thirteen of 27 patients had a hematocrit < 28%. Of these 13 patients, ten demonstrated postoperative myocardial ischemia and six sustained a morbid cardiac event. Of 14 patients with a hematocrit > or = 28%, two displayed myocardial ischemia and none sustained a morbid cardiac event. A hematocrit of < 28% was significantly associated with myocardial ischemia (p = .001) and morbid cardiac events (p = .0058). No significant differences in baseline heart rate and heart rate at the onset of myocardial ischemia were noted between the anemic and nonanemic patients.

CONCLUSIONS

This study suggests that postoperative anemia may play a role in postoperative myocardial ischemia and cardiac morbidity.

Predictive value of reactive hyperemia for cardiovascular events in patients with peripheral arterial disease undergoing vascular surgery

OBJECTIVE

Reactive hyperemia is the compensatory increase in blood flow that occurs after a period of tissue ischemia, and this response is blunted in patients with cardiovascular risk factors. The predictive value of reactive hyperemia for cardiovascular events in patients with atherosclerosis and the relative importance of reactive hyperemia compared with other measures of vascular function have not been previously studied.

METHODS AND RESULTS

We prospectively measured reactive hyperemia and brachial artery flow-mediated dilation by ultrasound in 267 patients with peripheral arterial disease referred for vascular surgery (age 66+/-11 years, 26% female). Median follow-up was 309 days (range 1 to 730 days). Fifty patients (19%) had an event, including cardiac death (15), myocardial infarction (18), unstable angina (8), congestive heart failure (6), and nonhemorrhagic stroke (3). Patients with an event were older and had lower hyperemic flow velocity (75+/-39 versus 95+/-50 cm/s, P=0.009). Patients with an event also had lower flow-mediated dilation (4.5+/-3.0 versus 6.9+/-4.6%, P<0.001), and when these 2 measures of vascular function were included in the same Cox proportional hazards model, lower hyperemic flow (OR 2.7, 95% CI 1.2 to 5.9, P=0.018) and lower flow-mediated dilation (OR 4.2, 95% CI: 1.8 to 9.8, P=0.001) both predicted cardiovascular events while adjusting for other risk factors.

CONCLUSIONS

Thus, lower reactive hyperemia is associated with increased cardiovascular risk in patients with peripheral arterial disease. Furthermore, flow-mediated dilation and reactive hyperemia incrementally relate to cardiovascular risk, although impaired flow-mediated dilation was the stronger predictor in this population. These findings further support the clinical relevance of vascular function measured in the microvasculature and conduit arteries in the upper extremity.

Cardiac troponin I predicts short-term mortality in vascular surgery patients

BACKGROUND

Cardiac troponin I (cTnI) is a highly sensitive and specific marker for myocardial injury that predicts outcomes in patients with acute coronary syndromes. Cardiovascular complications are the leading cause of morbidity and mortality in patients who have undergone vascular surgery. However, postoperative surveillance with cardiac enzymes is not routinely performed in these patients. We evaluated the association between postoperative cTnI levels and 6-month mortality and perioperative myocardial infarction (MI) after vascular surgery.

METHODS AND RESULTS

Two hundred twenty-nine patients having aortic or infrainguinal vascular surgery or lower extremity amputation were included in this study. Blood samples were analyzed for cTnI immediately after surgery and the mornings of postoperative days 1, 2, and 3. An elevated cTnI was defined as serum concentrations >1.5 ng/mL in any of the 4 samples. Twenty-eight patients (12%) had postoperative cTnI >1.5 ng/mL, which was associated with a 6-fold increased risk of 6-month mortality (adjusted OR, 5.9; 95% CI, 1.6 to 22.4) and a 27-fold increased risk of MI (OR, 27.1; 95% CI, 5.2 to 142.7). Furthermore, we observed a dose-response relation between cTnI concentration and mortality. Patients with cTnI >3.0 ng/mL had a significantly greater risk of death compared with patients with levels < or =0.35 ng/mL (OR, 4.9; 95% CI, 1.3 to 19.0).

CONCLUSIONS

Routine postoperative surveillance for cTnI is useful for identifying patients who have undergone vascular surgery who have an increased risk for short-term mortality and perioperative MI. Further research is needed to determine whether intervention in these patients can improve outcome.

Histopathology of in-stent restenosis in patients with peripheral artery disease

BACKGROUND

Clinical studies have suggested that smooth muscle cell (SMC) hyperplasia is the most likely cause of in-stent restenosis. However, pathological data regarding this issue are limited. Specifically, direct evidence of proliferative activity in tissues excised from stenotic stents has not been previously reported.

METHODS AND RESULTS

Tissue specimens were retrieved by directional atherectomy from 10 patients in whom in-stent restenosis complicated percutaneous revascularization of peripheral artery disease. Analysis of cellular composition was performed quantitatively after cell-specific immunostaining. For specimens preserved in methanol (7 of 10), cellular proliferation was evaluated by use of antibodies to proliferating cell nuclear antigen (PCNA), cyclin E, and cdk2. TUNEL staining for apoptosis was performed on 8 paraformaldehyde-preserved specimens. Each of the 10 specimens contained extensive foci of hypercellularity composed predominantly of SMCs (mean+/-SEM, 59.3+/-3.0%). Evidence of ongoing proliferative activity was documented in all 7 methanol-preserved specimens: 24.6+/-2.3% of SMCs were PCNA-positive, 24.8+/-3.1% were cyclin E-positive, and 22.5+/-2.2% were cdk2-positive. Apoptotic cells were detected in all 8 specimens that had been appropriately preserved to permit DNA nick-end labeling. Macrophages and leukocytes were identified in each of the 10 specimens but accounted for a proportionately smaller number of cells (14.5+/-1.9% and 9.5+/-1.4%, respectively). Organized thrombus was observed in 6 of the 10 specimens.

CONCLUSIONS

These findings support the notion that in-stent restenosis results from SMC hyperplasia and suggest that adjunctive therapies designed to inhibit SMC proliferation may further enhance the utility of endovascular stents.

Performance goals and endpoint assessments for clinical trials of femoropopliteal bare nitinol stents in patients with symptomatic peripheral arterial disease

OBJECTIVE

This analysis proposes safety and performance goals for prospective single-arm trials of bare nitinol stents to treat patients with debilitating claudication associated with femoropopliteal (FP) atherosclerotic lesions.

BACKGROUND

To date there have been no analyses of clinical trials data to set efficacy and safety benchmarks for new bare nitinol stents in the treatment of claudication from FP disease. Industry has been reluctant to sponsor studies of nitinol stents due to logistical barriers.

METHODS

VIVA Physician's, Inc. (VPI) analyzed subject-level data from the PTA control arm of three randomized FDA device trials conducted by industry. Subjects with Rutherford category 2-4 claudication and FP lesion lengths 4-15 cm with 12 month duplex ultrasound (DUS) assessment were identified. These data were combined with the results of a survey of the medical literature (1990-2006) for similar subjects.

RESULTS

Analysis of the industry derived control arm PTA data identified 116 patients (mean lesion length 8.7 cm) with a 12 month DUS defined FP patency of 28%. A similar cohort of 191 patients was identified from the medical literature in which the 12-month vessel patency equaled 37%; from these combined patient cohorts, expected vessel patency for PTA was estimated to equal 33%.

CONCLUSION

Based on the PTA performance efficacy rate of 33% derived from industry clinical trial data and the medical literature, and the requirement that the bare nitinol stent 12-month efficacy performance goal be set to equal twice this rate, the patency efficacy goal equals 66%. Additional information is provided on safety and other reporting standards and stent integrity evaluation for bare metal stents.

Thrombolysis or peripheral arterial surgery: phase I results. TOPAS Investigators

PURPOSE

Thrombolytic therapy is widely used in the treatment of peripheral arterial occlusion, but prospective, randomized comparisons with standard therapy remain few. A multicenter trial of thrombolysis or peripheral arterial surgery (TOPAS) was organized to compare critically the use of recombinant urokinase (rUK) or surgery for the initial treatment of acute lower-extremity ischemia. Phase I of the trial was designed as a dose-ranging trial to evaluate the safety and efficacy of three doses of rUK in comparison with surgery.

METHODS

In a multicenter, prospective, double-blind comparison, 213 patients who had acute lower-extremity ischemia for 14 days or fewer were randomized to one of two groups. The first group received one of three dosages of rUK (catheter-directed at 2000, 4000, or 6000 IU/min for 4 hours, then 2000 IU/min to a maximum of 48 hours). The second group underwent surgery. Successful thrombolysis was followed by surgical or endovascular interventions when anatomic lesions responsible for the occlusion were unmasked. Patients were followed-up for 1 year; data were evaluated on an intent-to-treat basis.

RESULTS

The 4000 IU/min rUK dosage was chosen as the most appropriate thrombolytic regimen because it maximized lytic efficacy against the risk of bleeding. Complete (> 95%) lysis of thrombus was achieved in 71% of the 49 patients who were randomized to the 4000 IU/min group, with a mean infusion time of 23 hours. In contrast, complete lysis was achieved in 67% of patients who received 2000 IU/min and in 60% of patients who received 6000 IU/min. Hemorrhagic complications occurred in 2% of the 4000 IU/min group versus 13% of the 2000 IU/min group (p = 0.05) and 16% of the 6000 IU/min group (p = 0.03). In a comparison of the 4000 IU/min group with the surgical group, the 1-year mortality rate (14% vs 16%) or amputation-free survival rate (75% vs 65%) did not differ significantly. The frequency and magnitude of surgery in the patients randomized to rUK were decreased (p < 0.001).

CONCLUSION

The preliminary results suggest that an initial rUK dose of 4000 IU/min is safe and efficacious in the treatment of acute lower-extremity ischemia. rUK therapy is associated with limb salvage and patient survival rates similar to those achieved with surgery, concurrent with a reduced requirement for complex surgery after thrombolytic intervention.

Bypass versus Angioplasty in Severe Ischaemia of the Leg (BASIL) trial: A survival prediction model to facilitate clinical decision making

BACKGROUND

An intention-to-treat analysis of the Bypass versus Angioplasty in Severe Ischaemia of the Leg (BASIL) trial showed that in patients with severe lower limb ischemia (SLI) due to infrainguinal disease who survived for 2 years after intervention, initial randomization to a bypass surgery (BSX)-first vs balloon angioplasty (BAP)-first revascularization strategy was associated with improvements in subsequent overall survival (OS) and amputation-free survival (AFS) of about 7 and 6 months, respectively. This study explored the value of baseline factors to estimate the likelihood of survival to 2 years for the trial cohort (Cox model) and for individual BASIL trial patients (Weibull model) as an aid to clinical decision making.

METHODS

Of 452 patients presenting to 27 United Kingdom hospitals, 228 were randomly assigned to a BSX-first and 224 to a BAP-first revascularization strategy. Patients were monitored for at least 3 years. Baseline factors affecting the survival of the entire cohort were examined with a multivariate Cox model. The chances of survival at 1 and 2 years for patients with given baseline characteristics were estimated with a Weibull parametric model.

RESULTS

At the end of follow-up, 172 patients (38%) were alive without major limb amputation of the trial leg, and 202 (45%) were alive. Baseline factors that were significant in the Cox model were BASIL randomization stratification group, below knee Bollinger angiogram score, body mass index, age, diabetes, creatinine level, and smoking status. Using these factors to define five equally sized groups, we identified patients with 2-year survival rates of 50% to 90%. The factors that contributed to the Weibull predictive model were age, presence of tissue loss, serum creatinine, number of ankle pressure measurements detectable, maximum ankle pressure measured, a history of myocardial infarction or angina, a history of stroke or transient ischemia attack, below knee Bollinger angiogram score, body mass index, and smoking status.

CONCLUSIONS

Patients in the BASIL trial were at high risk of amputation and death regardless of revascularization strategy. However, baseline factors can be used to stratify those risks. Furthermore, within a parametric Weibull model, certain of these factors can be used to help predict outcomes for individuals. It may thus be possible to define the clinical and anatomic (angiographic) characteristics of SLI patients who are likely-and not likely-to live for >2 years after intervention. Used appropriately in the context of the BASIL trial outcomes, this may aid clinical decision making regarding a BSX- or BAP-first revascularization strategy in SLI patients like those randomized in BASIL.

Physical, mental, and social predictors of functional outcome in unilateral lower-limb amputees

OBJECTIVE

To study the value of physical, mental, and social characteristics as predictors of functional outcome of elderly amputees.

DESIGN

Prospective, inception cohort study; comparisons with reference populations.

SETTING

Main hospitals, rehabilitation centers, nursing homes, patients' own residence settings in 1 of the 3 northern provinces in the Netherlands.

PARTICIPANTS

Forty-six patients older than 60 years, with unilateral transtibial or transfemoral amputation or knee disarticulation because of vascular disease.

INTERVENTIONS

Measurement of physical, mental, and social predictors 2 and 6 weeks postamputation.

MAIN OUTCOME MEASURES

The Sickness Impact Profile (SIP-68), Groningen Activity Restriction Scale (GARS), Timed up and go (TUG) test, and prosthetic use.

RESULTS

A total of 15% of amputees died within the first year after amputation. Seventy percent lived independently at home 1 year postamputation. The functional level of the patients was low, as shown by high scores on the SIP-68 (mean, 23.6), GARS (mean, 41.2), and TUG test (mean, 23.9s). Functionally effective prosthetic use, as measured with the classification of Narang and Pohjolainen, was reached by 49%. For the SIP-68 scores, age, comorbidity, 1-leg balance, and the 15-word test predicted functional outcome in 69% of amputees. For the GARS score, age, 1-leg balance, and the 15-word test predicted functional outcome in 64%. For the TUG test, age and 1-leg balance predicted functional outcome in 42% of amputees. After correction for age, the only significant predictor for prosthetic use was 1-leg balance.

CONCLUSIONS

Elderly patients with a leg amputation had a low functional level 1-year postamputation. An important part of functional outcome could be predicted 2 weeks after amputation by age at amputation, 1-leg balance on the unaffected limb, and cognitive impairment. Severe comorbidity probably also played a role. The results may be used in the general policy concerning leg amputees.

Contemporary management of aortic branch compromise resulting from acute aortic dissection

PURPOSE

In an earlier report, we documented the incidence and impact of aortic branch compromise complicating acute aortic dissection (AD) over a 21-year interval (1965-1986). In the current study, management of peripheral vascular complications (PVCs) of AD over the past decade was reviewed.

METHODS

Medical records of patients treated for AD over the interval January 1, 1990, to December 31, 1999, were reviewed. Patients with branch compromise confirmed with radiography or operation and patients with spinal cord ischemia that was based on results of a physical examination defined the study group. Comparisons between subgroups with and without PVC over a 30-year interval were analyzed with the chi(2) test.

RESULTS

A total of 187 patients (101 proximal and 86 distal) were treated for AD over the study interval. A total of 53 (28%) of these patients had clinical evidence of organ or limb malperfusion (7 cerebral, 3 upper extremity, 5 spinal cord, 11 mesenteric, 12 renal, and 24 lower extremity [sites inclusive]), and one of three (17 patients) of these underwent specific peripheral vascular intervention. The remaining 65% (36) of the PVC group had complete or partial malperfusion resolution after central aortic therapy (medical or surgical) alone. Open techniques for treating PVC included aortic fenestration (9), femorofemoral grafting (2), and aortofemoral grafting (1). All had favorable outcomes with no mortality. Endovascular procedures in five patients included abdominal aortic fenestration (3) or stenting of the renal (2), mesenteric (2), and iliac (1) arteries with clinical success in three patients and two deaths. The in-hospital mortality rate for the entire group of 187 patients was 18% (15% for proximal aortic operation, 8% in medically treated patients). The presence of aortic branch compromise was not a statistically significant predictor of the patient mortality rate (23% with and 16% without; P =.26). Overall mortality rate in the current study (18% vs 37%; P =.000006) and the mortality rate with PVC (23% vs 51%; P =.001), in particular with mesenteric ischemia (36% vs 87%; P =.026), decreased significantly when compared with prior experience.

CONCLUSIONS

The overall mortality rate from AD during the past decade has decreased significantly. Similar trends were noted in patients with PVCs, a previously identified high-risk subgroup. Increased awareness and prompt, specific management of PVCs, in particular when visceral ischemia is present, have contributed to improved outcomes in patients with AD.

Patients with early-onset peripheral vascular disease have increased levels of autoantibodies against oxidized LDL

Oxidative modification of LDL has been proposed as an early and crucial step in the development of atherosclerosis, and antibodies against such modified LDL are found in both healthy individuals and patients with atherosclerosis. In this study, 62 patients who were surgically treated for peripheral arterial occlusive disease below the age of 50 were investigated and compared with age- and sex-matched healthy individuals in a case-control study. Autoantibodies against oxidized LDL were measured with an enzyme-linked immunosorbent assay method. Risk factors such as smoking, hypertension, family history of premature cardiovascular events, and lipoprotein levels were also determined. The patients had significantly higher levels of autoantibodies against oxidized LDL; significantly higher levels of total cholesterol, LDL cholesterol, triglycerides, and apo A-I; and significantly lower levels of HDL cholesterol than did control subjects. In multivariate analyses autoantibodies against oxidized LDL discriminated better between patients and control subjects than did any of the different lipoprotein analyses. Among patients, the presence of hypertension and a family history of cardiovascular events were the only factors significantly associated with increased levels of autoantibodies against oxidized LDL.

Dobutamine stress echocardiography predicts surgical outcome in patients with an aortic aneurysm and peripheral vascular disease

OBJECTIVES

This study was conducted to assess the utility of dobutamine stress echocardiography for determining the presence of significant coronary artery disease and for predicting surgical outcome and long-term prognosis in patients scheduled to undergo peripheral vascular or aortic aneurysm surgery.

BACKGROUND

Assessment of coronary artery disease in patients scheduled to undergo peripheral vascular surgery can avoid perioperative complications.

METHODS

Dobutamine stress echocardiography was performed in 98 consecutive patients scheduled to undergo aortic or peripheral vascular surgery. Intravenous dobutamine was infused in a graded fashion, with two-dimensional digital echocardiographic monitoring of ventricular function and segmental wall motion. Group 1 (n = 70) consisted of patients who exhibited a normal response to dobutamine infusion (negative dobutamine study); group 2 (n = 23) comprised those patients with an abnormal response to dobutamine, characterized by the development of new or worsening wall motion abnormalities at rest, indicating the presence of myocardial ischemia (positive dobutamine study). Five patients with an inconclusive dobutamine study (because of inadequate heart rate) were excluded from analysis.

RESULTS

No major adverse effects occurred with testing in any patient. Sixty-eight of 70 patients with a negative study had peripheral vascular or aortic surgery performed without perioperative cardiac events (2 patients refused surgery). Nineteen of 23 patients with a positive study underwent coronary angiography and all had > 50% lumen narrowing in one or more major coronary artery distributions; 13 underwent coronary artery bypass grafting or angioplasty before peripheral vascular or aortic surgery and all had an uneventful perioperative period. Four of the 10 patients from group 2 who did not undergo coronary revascularization had a perioperative cardiac event (myocardial infarction in 2, an ischemic episode requiring urgent coronary bypass grafting in 1 and congestive heart failure in 1).

CONCLUSIONS

Positive and negative dobutamine study results are significant predictors of the presence or absence of perioperative events (20% vs. 0%, p = 0.003). A positive test warrants coronary angiography and further medical or surgical intervention, or both, but a negative test indicates a low likelihood of perioperative cardiac complications of aortic or peripheral vascular surgery. During the long-term follow-up period in this study (group 1 mean, 24 months; group 2 mean, 15 months), two patients (3%) from group 1 and three (15%) from group 2 developed cardiac complications (p = 0.038). Thus, dobutamine stress echocardiography is safe and can predict surgical outcome in patients undergoing aortic aneurysm repair or surgery for occlusive disease of the peripheral arteries. In addition, a negative test result is a strong predictor of decreased perioperative and long-term cardiac morbidity and mortality.

Patient recovery after infrainguinal bypass grafting for limb salvage

PURPOSE

The outcome of infrainguinal bypass surgery for limb salvage has traditionally been assessed by graft patency rates, limb salvage rates, and patient survival rates. Recently, functional outcome of limb salvage surgery has been assessed by patient ambulatory status and independent living status. These assessments fail to consider the adverse long-term patient effects of delayed wound healing, episodes of recurrent ischemia, and need for repeat operations. An ideal result of infrainguinal bypass surgery for limb salvage includes an uncomplicated operation, elimination of ischemia, prompt wound healing, and rapid return to premorbid functional status without recurrence or repeat surgery. The present study was performed to determine how often this ideal result is actually achieved.

METHODS

The records of 112 consecutive patients who underwent initial infrainguinal bypass surgery for limb salvage 5 to 7 years before the study were reviewed for operative complications, graft patency, limb salvage, survival, patient functional status, time to achieve wound healing, need for repeat operations, and recurrence of ischemia.

RESULTS

The mean patient age was 66 years. The mean postoperative follow-up was 42 months (range, 0 to 100.1 months). After operation 99 patients (88%) lived independently at home and 103 (92%) were ambulatory. There were seven perioperative deaths (6.3%), and wound complications occurred in 27 patients (24%). By life table, the assisted primary graft patency and limb salvage rates of the index extremity 5 years after operation were 77% and 87%, respectively, and the patient survival rate was 49%. At last follow-up or death, 73% of the patients (72 of 99) who lived independently at home before the operation were still living independently at home, and 70% (72 of 103) of those who were ambulatory before the operation remained ambulatory. Wound (operative and ischemic) healing required a mean of 4.2 months (range, 0.4 to 48 months), and 25 patients (22%) had not achieved complete wound healing at the time of last follow-up or death. Repeat operations to maintain graft patency, treat wound complications, or treat recurrent or contralateral ischemia were required in 61 patients (54%; mean, 1.6 reoperations/patient), and 26 patients (23.2%) ultimately required major limb amputation of the index or contralateral extremity. Only 16 of 112 patients (14.3%) achieved the ideal surgical result of an uncomplicated operation with long-term symptom relief, maintenance of functional status, and no recurrence or repeat operations.

CONCLUSIONS

Most patients who undergo infrainguinal bypass surgery for limb salvage require ongoing treatment and have persistent or recurrent symptoms until their death. A significant minority have major tissue loss despite successful initial surgery. Clinically important palliation is frequently achieved by bypass surgery, but ideal results are distinctly infrequent.

Disparity in outcomes of surgical revascularization for limb salvage: race and gender are synergistic determinants of vein graft failure and limb loss

BACKGROUND

Vein bypass surgery is an effective therapy for atherosclerotic occlusive disease in the coronary and peripheral circulations; however, long-term results are limited by progressive attrition of graft patency. Failure of vein bypass grafts in patients with critical limb ischemia results in morbidity, limb loss, and additional resource use. Although technical factors are known to be critical to the success of surgical revascularization, patient-specific risk factors are not well defined. In particular, the relationship of race/ethnicity and gender to the outcomes of peripheral bypass surgery has been controversial.

METHODS AND RESULTS

We analyzed the Project of Ex Vivo Vein Graft Engineering via Transfection III (PREVENT III) randomized trial database, which included 1404 lower extremity vein graft operations performed exclusively for critical limb ischemia at 83 North American centers. Trial design included intensive ultrasound surveillance of the bypass graft and clinical follow-up to 1 year. Multivariable modeling (Cox proportional hazards and propensity score) was used to examine the relationships of demographic variables to clinical end points, including perioperative (30-day) events and 1-year outcomes (vein graft patency, limb salvage, and patient survival). Final propensity score models adjusted for 16 covariates (including type of institution, technical factors, selected comorbidities, and adjunctive medications) to examine the associations between race, gender, and outcomes. Among the 249 black patients enrolled in PREVENT III, 118 were women and 131 were men. Black men were at increased risk for early graft failure (hazard ratio [HR], 2.832 for 30-day failure; 95% confidence interval [CI], 1.393 to 5.759; P=0.0004), even when the analysis was restricted to exclude high-risk venous conduits. Black patients experienced reduced secondary patency (HR, 1.49; 95% CI, 1.08 to 2.06; P=0.016) and limb salvage (HR, 2.02; 95% CI, 1.27 to 3.20; P=0.003) at 1 year. Propensity score models demonstrate that black women were the most disadvantaged, with an increased risk for loss of graft patency (HR, 2.02 for secondary patency; 95% CI, 1.27 to 3.20; P=0.003) and major amputation (HR, 2.38; 95% CI, 1.18 to 4.83; P=0.016) at 1 year. Perioperative mortality and 1-year mortality were similar across race/gender groups.

CONCLUSIONS

Black race and female gender are risk factors for adverse outcomes after vein bypass surgery for limb salvage. Graft failure and limb loss are more common events in black patients, with black women being a particularly high-risk group. These data suggest the possibility of an altered biological response to vein grafting in this population; however, further studies are needed to determine the mechanisms underlying these observed disparities in outcome.

Long-Segment SFA Stenting—The Dark Sides: In-Stent Restenosis, Clinical Deterioration, and Stent Fractures

PURPOSE

To determine and compare the rates of in-stent restenosis, late clinical deterioration, and stent fractures in nitinol stents versus Wallstents implanted for suboptimal angioplasty in the superficial femoral artery (SFA).

METHODS

Interrogation of an angioplasty database identified 286 consecutive patients (178 men; mean age 67+/-10 years, range 44-87) with severe claudication (n=254) or critical limb ischemia (n=32) who had stents implanted after suboptimal angioplasty over a 5-year period. Wallstents with a mean stented lesion length of 107+/-71 mm were implanted in 116 patients, while nitinol stents were used in 170 patients: 45 SMART stents (mean stented lesion length 139+/-88 mm) and 125 Dynalink/Absolute stents (mean stented lesion length 125+/-84 mm). Patients were followed for in-stent restenosis (>50%) by duplex ultrasound, clinical deterioration by at least 1 Fontaine stage compared to baseline, and stent fractures by biplanar radiography.

RESULTS

In-stent restenosis rates at 1, 2, and 3 years were 46%, 66%, and 72% for Wallstents compared to 20%, 36%, and 53% for nitinol stents (p<0.001), respectively, without significant difference between the 2 nitinol stent groups (p=0.59). Clinical deterioration at 1, 2, and 3 years was found in 10%, 15%, and 18% with Wallstents versus 4%, 5%, and 5% with nitinol stents (p=0.014), respectively, without difference between the 2 nitinol stent groups (p=0.47). Fracture rates were 19% for Wallstents after a mean 43+/-24 months, 28% for SMART stents after mean 32+/-16 months, and 2% for Dynalink/Absolute stents after a mean 15+/-9 months.

CONCLUSIONS

Intermediate-term in-stent restenosis remains a major problem even with current nitinol stent technology; however, clinical deterioration seems no matter of serious concern with SMART and Dynalink/Absolute stents. Stent fractures may be lower with Dynalink/Absolute stents, but randomized head-to-head comparisons are needed to validate these data.