Duplex scan characteristics of bypass grafts to mesenteric arteries.

BACKGROUND: Mesenteric bypass grafts may be followed postoperatively with duplex scanning. It is unknown, however, if duplex-derived velocity measurements vary over time or if the type of procedure (antegrade vs retrograde) and the caliber of graft affect velocity measurements. The purpose of this study was to characterize duplex findings in mesenteric bypass grafts with respect to the type of revascularization, graft caliber, and changes over time. This study also sought to identify duplex characteristics that could predict subsequent graft failure. METHODS: Duplex examinations of mesenteric bypass grafts were reviewed. Peak systolic velocities (PSV) from the inflow artery, proximal anastomosis, mid graft, distal anastomosis, and outflow arteries were analyzed with respect to timing of the examination (index study vs follow-up exam), inflow source, distal target, and graft diameter. The results were compared with analysis of variance (P < .05). Univariate and multivariate analyses were used to determine any association with mid-graft PSV. RESULTS: Fasting postoperative duplex scans were reviewed from 43 mesenteric bypass grafts in 38 patients (28 superior mesenteric artery [SMA] alone, 3 celiac alone, 5 celiac and SMA, 2 SMA and renal). A total of 167 duplex exams were analyzed (mean of 4.5 studies per patient; range, 1 to 14). Inflow artery velocities were significantly lower in antegrade vs retrograde configurations (93 +/- 73 cm/s vs 154 +/- 73 cm/s, P < .05); however, proximal and mid-graft PSVs were not significantly different between the two groups. In addition, no effect was noted on mid-graft PSV when distal targets were compared (SMA vs celiac, 149 +/- 42 cm/s vs 160 +/- 78 cm/s, P = NS). An association between smaller graft diameter and higher mid-graft PSV was seen with univariate analysis (P = .03), with a trend toward significance with multivariate analysis (P = .06). In 18 bypass grafts where a follow-up examination was available >1 year (mean 38 +/- 25 months) after the index postoperative exam, velocity did not significantly change over time. No duplex scan characteristics were predictive of graft thrombosis. CONCLUSION: This is the first study, to our knowledge, to fully characterize duplex-derived flow velocities in mesenteric artery bypass grafts. Although surveillance duplex scans after mesenteric bypass procedures may be affected by graft diameter, they are not significantly affected by the choice of inflow artery. These data can serve as standards for postoperative surveillance of mesenteric bypass grafts.

Prospective evaluation of the relationship between C-reactive protein, D-dimer and progression of peripheral arterial disease.

OBJECTIVE: Elevated levels of C-reactive protein (CRP) and D-dimer (DD) have been associated with the presence and progression of various forms of atherosclerotic disease, particularly coronary heart disease. We hypothesize that there is a relationship between elevated levels of baseline CRP and DD and progression of peripheral arterial disease (PAD) in patients with symptomatic PAD. The current study is a prospective evaluation of this hypothesis. METHODS: Between 1996 and 2003, 384 subjects were enrolled in a National Institutes of Health-sponsored blinded, prospective trial evaluating the effects of multiple atherosclerotic risk factors on progression of symptomatic PAD. Baseline levels of CRP and D-dimer were obtained in 332 subjects. Subjects were followed every 6 months with clinical history and exam, ankle-brachial pressure index (ABI), and carotid artery duplex scanning (CDS). The primary study end point was a composite of ABI progression, CDS progression, stroke, myocardial infarction, amputation, and death from cardiovascular disease. Secondary end points included each of the components of the primary end point. The relationship between time to the various endpoints and baseline CRP and DD levels was examined by life-table analysis and Cox proportional hazards analysis. RESULTS: Adequate baseline samples for CRP and DD were available in 332 subjects (mean age, 67 years; 57.8% men) with mean follow-up of 38.4 months (range, 1 to 99 months). Mean baseline levels (+/- SD) for CRP were 0.8 +/- 1.14 (range, 0.03 to 13.0), and mean DD levels were 227.4 +/- 303.3 (range, 1.9 to 2744.8). Progression, as defined by the primary end point, occurred in 48.5% of subjects. Subjects with elevated CRP (highest tertile) were no more likely to have any of the progression end points than those with the lowest values (lowest tertile) (P = NS, log-rank test, for all comparisons). By univariate analysis, subjects with elevated DD (highest tertile) were significantly more likely to die from any cause compared with subjects with the lowest DD values (lowest tertile) (P = .03, log-rank test). They were, however, no more likely to reach any of the other progression end points, including the primary end point (P = NS, log-rank test for all other comparisons). Multivariate analysis showed that DD level was a significant independent variable associated with occurrence of myocardial infarction (hazard ratio, 2.3; P = .02). CONCLUSIONS: In subjects with symptomatic PAD, elevated baseline DD, a marker of thrombotic activity, was significantly associated with the occurrence of myocardial infarction. This study did not confirm a relationship between progression of PAD and baseline DD or CRP during the first 3 years. Baseline DD and CRP do not provide useful risk stratification in patients at high risk for progression of symptomatic PAD. Future studies should evaluate serial levels of these markers to assess their utility in predicting progression of symptomatic PAD.

D-dimer and inflammatory markers as predictors of functional decline in men and women with and without peripheral arterial disease.

OBJECTIVES: To determine whether higher circulating levels of inflammatory and thrombotic markers are associated with greater decline in lower extremity performance. DESIGN: Prospective cohort. SETTING: Academic medical center. PARTICIPANTS: Three hundred thirty-seven men and women with lower extremity peripheral arterial disease (PAD) and 215 without PAD. MEASUREMENTS: Objective measures of leg function, including the 6-minute walk and Short Physical Performance Battery (SPPB), were obtained at baseline and annually for 3 years. D-dimer, high-sensitivity C-reactive protein, serum amyloid A, and fibrinogen levels were measured at baseline. Participants were categorized into one of three groups, ranging from low to high levels of inflammation, depending on the number of individual blood factors in the lowest and highest tertiles for each corresponding blood factor. RESULTS: Adjusting for age, sex, race, ankle brachial index, comorbidities, and other confounders, greater inflammation was associated with greater decline in the SPPB (P=.008). Results were similar when repeated in participants with and without PAD separately (P for trend=.04 for participants with PAD and .07 for participants without PAD). In fully adjusted analyses, there were no significant associations between inflammation group and decline in 6-minute walk performance. CONCLUSION: Higher baseline levels of inflammatory markers and D-dimer were associated with greater decline in the SPPB at 3-year follow-up in persons with and without PAD.

Inflammatory and thrombotic blood markers and walking-related disability in men and women with and without peripheral arterial disease.

OBJECTIVES: To determine whether higher circulating levels of thrombotic and inflammatory markers are associated with greater disability. DESIGN: Cross-sectional. SETTING: Academic medical center. PARTICIPANTS: A total of 346 men and women with peripheral arterial disease (PAD) and 203 without PAD. MEASUREMENTS: Disability measures were the Walking Impairment Questionnaire (WIQ) distance, speed, and stair-climbing scores and the 36-item Short-Form (SF-36) physical functioning score. The SF-36 and WIQ are scored on a 0 to 100 scale (100=best). RESULTS: In persons with PAD, higher D-dimer levels were associated with lower WIQ speed scores (P<.001), lower stair-climbing scores (P<.04), and poorer SF-36 physical functioning scores (P<.01), adjusting for known and potential confounders. In participants without PAD, higher D-dimer levels were associated with lower WIQ distance scores (P<.03), lower speed scores (P<.05), and poorer SF-36 physical functioning scores (P<.02). Higher high-sensitivity C-reactive protein (hsCRP) levels were associated with lower WIQ distance (P<.02) and speed scores (P<.001) in persons without PAD. Most of these associations were attenuated after additional adjustment for objectively measured functional limitations. CONCLUSION: Higher circulating D-dimer and hsCRP levels are associated with greater disability in walking and physical functioning in individuals with and without PAD. Physiological changes that result in walking disability may mediate these associations.

Outcomes after redo procedures for failed mesenteric revascularization.

This report examines results of mesenteric revascularization following a failed splanchnic revascularization. Patients undergoing repeat mesenteric revascularization from January 1985 to July 2002 were identified from a prospectively maintained registry. Data recorded included procedures performed, perioperative mortality, complications, and operative indications. Patients who had embolic events were excluded. Eighty-six patients underwent 105 mesenteric interventions in this time period; 22 patients underwent 33 repeat mesenteric revascularization procedures. There were 25 single-vessel bypasses, 3 multivessel reconstructions, 3 angioplasty procedures (1 open, 2 percutaneous), and 2 graft thrombectomies. Complications occurred in 33.3%. Perioperative mortality was 6.1%, all in patients with acute mesenteric ischemia. One- and 4-year primary patency for repeat mesenteric revascularization was 73.5% and 62.2%, respectively, and survival for repeat mesenteric revascularization was 85.9% and 75.5%, respectively. Patients surgically treated for mesenteric ischemia can require additional interventions. Repeat revascularization effectively prolongs survival when an earlier intervention fails.

Functional decline in peripheral arterial disease: associations with the ankle brachial index and leg symptoms.

CONTEXT: Among individuals with lower-extremity peripheral arterial disease (PAD), specific leg symptoms and the ankle brachial index (ABI) are cross-sectionally related to the degree of functional impairment. However, relations between these clinical characteristics and objectively measured functional decline are unknown. OBJECTIVE: To define whether PAD, ABI, and specific leg symptoms predict functional decline at 2-year follow-up. DESIGN, SETTING, AND PARTICIPANTS: Prospective cohort study among 676 consecutively identified individuals (aged > or =55 years) with and without PAD (n = 417 and n = 259, respectively), with baseline functional assessments occurring between October 1, 1998, and January 31, 2000, and follow-up assessments scheduled 1 and 2 years thereafter. PAD was defined as ABI less than 0.90, and participants with PAD were categorized at baseline into 1 of 5 mutually exclusive symptom groups. MAIN OUTCOME MEASURES: Mean annual changes in 6-minute walk performance and in usual-paced and fast-paced 4-m walking velocity, adjusted for age, sex, race, prior-year functioning, comorbid diseases, body mass index, pack-years of cigarette smoking, and patterns of missing data. RESULTS: Lower baseline ABI values were associated with greater mean (95% confidence interval) annual decline in 6-minute walk performance (-73.0 [-142 to -4.2] ft for ABI <0.50 vs -58.8 [-83.5 to -34.0] ft for ABI 0.50 to <0.90 vs -12.6 [-40.3 to 15.1] ft for ABI 0.90-1.50, P =.02). Compared with participants without PAD, PAD participants with leg pain on exertion and rest at baseline had greater mean annual decline in 6-minute walk performance (-111 [-173 to -50.0] ft vs -8.67 [-36.9 to 19.5] ft, P =.004), usual-pace 4-meter walking velocity (-0.06 [-0.09 to -0.02] m/sec vs -0.01 (-0.03 to 0.003] m/sec, P =.02), and fastest-pace 4-meter walking velocity (-0.07 [-0.11 to -0.03] m/sec vs -0.02 [-0.04 to -0.006] m/sec, P =.046). Compared with participants without PAD, asymptomatic PAD was associated with greater mean annual decline in 6-minute walk performance (-76.8 (-135 to -18.6] ft vs -8.67 (-36.9 to 19.5] ft, P =.04) and an increased odds ratio for becoming unable to walk for 6 minutes continuously (3.63; 95% confidence interval, 1.58-8.36; P =.002). CONCLUSIONS: Baseline ABI and the nature of leg symptoms predict the degree of functional decline at 2-year follow-up. Previously reported lack of worsening in claudication symptoms over time in patients with PAD may be more related to declining functional performance to than lack of disease progression.

Iatrogenic arterial injury is an increasingly important cause of arterial trauma.

BACKGROUND: Iatrogenic arterial injuries (IAI) may result from any invasive diagnostic or therapeutic procedure. The relative occurrence and severity of IAI compared with those of penetrating and blunt vascular trauma is unknown. A review of arterial trauma at a university hospital level 1 trauma center, with a focus on iatrogenic injury, forms the basis of this report. METHODS: Patients treated for arterial trauma from January 1994 through October 2002 were identified from prospectively maintained registries. Record review included injury etiology, type of repair, 30-day all-cause mortality, and permanent morbidity. Permanent morbidity was defined as amputation or loss of extremity function. RESULTS: In all, 252 patients required treatment, 85 (33.7%) from IAI, 86 (34.1 %) from penetrating trauma, and 81 (32.1%) from blunt trauma. During the study period, the number of IAIs per year increased. Femoral artery injury from percutaneous intervention (50, 58.8%) was the most frequent IAI; intraoperative injury (including 14 tumor resections and 5 orthopedic procedures) was next most frequent (23, 27.1%). Three patients (3.5%) with IAI had permanent morbidity. The 30-day all-cause mortality was 7.1% (6) for patients with IAI. CONCLUSIONS: Iatrogenic arterial injury is increasingly frequent and caused one third of the arterial trauma at our level 1 trauma center. These data suggest education and training regarding IAI deserves equal priority with the study of penetrating vascular trauma.

Risk factors for autogenous infrainguinal bypass occlusion in patients with prosthetic inflow grafts.

OBJECTIVE: In patients with prosthetic inflow (PI) grafts the proximal anastomosis of autogenous infrainguinal bypass (AIB) can be placed on the PI or on a distal native vessel in the groin. This study was performed to determine the effect of placement of an AIB proximal anastomotic site in a patient with ipsilateral PI. METHODS: Patients undergoing AIB and PI between January 1990 and July 2002 were included in the study. They were classified into two groups on the basis of location of the proximal anastomosis. In group 1 the AIB proximal anastomosis was placed on the PI in the groin, whereas in group 2 the AIB proximal anastomosis was placed on a distal native groin artery. Patency, limb salvage, and patient survival in the two groups were calculated with the Kaplan-Meier method. The Cox proportional hazards model was used to determine independent risk factors affecting AIB patency. RESULTS: Two hundred twenty-nine patients underwent AIB and PI. In group 1, 23 AIBs became thrombosed concurrent with 26 PI occlusions, and in group 2, 7 AIBs became thrombosed concurrent with 36 PI occlusions (P <.001). Five-year assisted primary patency, limb salvage, and patient survival in groups 1 and 2 were 50% and 75% (P <.001, log-rank test), 78% and 90% (P =.005, log-rank test), and 56% and 69% (P = NS, log-rank test), respectively. Factors independently associated with AIB occlusion are hypertension (hazard ratio [HR], 3.41; 95% confidence interval [CI], 1.65-7.05; P =.001), postoperative warfarin sodium therapy (HR, 1.86; 95% CI, 1.07-3.23; P =.03), continued smoking (HR, 1.72; 95% CI, 0.93-3.18; P =.08), AIB arising from PI (HR, 2.38; 95% CI, 1.35-4.18; P =.003), and PI occlusion (HR, 3.70; 95% CI, 2.15-6.36; P <.001). CONCLUSION: A proximal AIB anastomosis located directly on the PI is an independent risk factor for decreased AIB patency of equal or greater importance than current smoking, hypertension, or PI occlusion. The proximal anastomosis of an AIB in a patient with an ipsilateral PI should be placed on a distal native artery.

Prospective randomized multicenter trial of fibrin sealant versus thrombin-soaked gelatin sponge for suture- or needle-hole bleeding from polytetrafluoroethylene femoral artery grafts.

OBJECTIVE: We evaluated the safety and efficacy of the fibrin sealant Beriplast P (FSBP; Aventis-Behring) for hemostasis in anastomosis of polytetrafluoroethylene (PTFE) grafts to the femoral artery. METHODS: In a single-blinded randomized prospective multicenter clinical trial, FSBP was compared with thrombin-soaked gelatin sponge (TSG) for efficacy in stopping bleeding from needle or suture holes in PTFE grafts after anastomosis to the femoral artery. Patients were randomized to FSBP application, which requires a 3-minute period of arterial clamping to enable the fibrin clot to adhere, or to TSG application, which requires pressure from gauze sponges, after completion of the femoral artery anastomosis. The primary end point was hemostasis, defined as absence of any detectable bleeding as judged by the operating surgeon, by 4 minutes after randomization. Secondary end points included actual time from randomization to hemostasis, time to beginning of wound closure, measured blood loss (weighed sponges), incidence of recurrent bleeding, stay in the intensive care unit, and hospital length of stay. Data were analyzed with the intention-to-treat method. RESULTS: Two hundred thirty-five subjects were enrolled at 26 medical centers; 34 were subsequently excluded from the study. Of the 201 randomized subjects, 100 received FSBP and 99 received TSG. Hemostasis was achieved by 4 minutes in 64 subjects (63%) in the FSBP group and 40 subjects (40%) in the TSG group (P =.0018). In the FSBP group, compared with the TSG group, time to hemostasis was shorter (median, 4.0 minutes; 95% confidence interval [CI], 3.8-4.18 minutes vs median, 5.6 minutes, 95% CI, 4.5-7.0; P =.008), blood loss was less (mean, 4.0 +/- 29.7 g vs mean, 15.6 +/- 28.4 g; P <.0001), and time to wound closure was shorter (median, 15 minutes; 95% CI, 10.47-18.67 minutes vs median, 22.8 minutes; 95% CI, 18.67-30.67; P =.005). There were no differences in recurrent bleeding or any other adverse events. There was no significant difference in ICU stay, but hospital length of stay was shorter in the FSBP group compared with the TSG group, and the difference approached significance (median, 6.5 days; 95% CI, 5.00-7.00 days vs median, 7.0 days; 95% CI,. 6.00-8.00 days; P =.0565). CONCLUSION: FSBP is more effective than TSG for achieving hemostasis of needle or suture hole bleeding from PTFE femoral artery grafts.

Elevated plasma homocysteine as risk factor for peripheral arterial disease--what is the evidence?

There is abundant evidence that elevated plasma homocysteine (HC) is independently associated with presence of atherosclerotic disease. There is credible evidence from a number of prospective studies that elevated HC is independently associated with progression of atherosclerotic disease. All studies to date agree that vitamin therapy, primarily folate, results in reliable decreases in HC, without recognized toxicity or side effects. Two small, randomized clinical trials have demonstrated clinically relevant benefit from folate treatment, which reduced HC in patients, compared to placebo. The results of multiple large scale clinical trials will be available within 2 to 5 years, and these have sufficient power to determine whether vitamin therapy intended to lower plasma HC will be established as the first effective therapy for atherosclerosis that does not involve expensive medication with toxic side effects and/or difficult changes in habits or lifestyle.

Comparison of procedural outcomes after lower extremity reversed vein grafting and secondary surgical revision.

OBJECTIVE: Many lower extremity vein graft procedures require revision. Although morbidity associated with revision procedures is assumed minimal, this has not been previously quantified and may be underestimated. In this study, patient outcome after initial vein graft procedures and revisions are compared. METHODS: Records for all patients undergoing vein graft revision from January 1995 to August 2002 were reviewed for operation time, estimated blood loss, blood transfusion, hospital length of stay, perioperative complications, and functional status at discharge and at 2-month follow-up. Revisions were compared with the original operation and by revision type. RESULTS: One hundred sixty-five vein graft revisions were performed in 137 patients. In comparison with the initial bypass procedure, mean operation time (3.35 +/- 1.41 hours vs 2.58 +/- 1.04 hours; P <.001), estimated blood loss (272.4 +/- 249.9 mL vs 174.8 +/- 140.8 mL; P <.001), hospital length of stay (10.15 +/- 4.85 days vs 7.05 +/- 5.14; P <.001), and overall complication rate (35.8% vs 22.4%; P =.015) were significantly less for revision procedures. Revision of more than one site on the graft resulted in longer operation time (P =.003) and estimated blood loss (P <.001), but similar complication rates (P = NS), compared with revision at only one site. Revisions that involved only the graft resulted in decreased hospital length of stay compared with revisions involving extension to native inflow or outflow vessels (P <.02). Return to preoperative ambulatory status at discharge was 71% after initial operation, and was 92% after revision (P <.001). Return to independent living at discharge was 66% after the initial operation, and was 80% after revision (P <.01). CONCLUSIONS: Operative revisions were better tolerated than initial vein graft procedures, but are still major procedures. Hospital length of stay is longer for patients undergoing proximal or distal extension of the graft to native vessels and in patients who are not ambulatory and living independently at discharge. Patients undergoing vein graft revision should be counseled about potential morbidity.

Depressive symptoms and lower extremity functioning in men and women with peripheral arterial disease.

OBJECTIVE: Factors associated with impaired functioning in patients with lower extremity peripheral arterial disease (PAD) are not fully understood. The purpose of this study was to determine the relationship between depressive symptoms and objective measures of lower extremity functioning in persons with PAD. DESIGN: Cross-sectional. PATIENTS/PARTICIPANTS: Four hundred twenty-three men and women with PAD identified from 3 Chicago area medical centers. MEASUREMENTS AND MAIN RESULTS: PAD was defined as ankle brachial index (ABI) <0.90. The Geriatric Depression Scale short form (GDS-S) (0-15 scale, 15 = worst) was completed by all participants. A clinically significant number of depressive symptoms was defined as a GDS-S score >or=6. Six-minute walk distance and usual-and fast-pace walking velocity were determined for all participants. A GDS-S score >or=6 was present in 21.7% of participants with PAD. Adjusting for age, increasing numbers of depressive symptoms were associated with an increasing prevalence of leg pain on exertion and rest (P =.004). Adjusting for age, sex, race, ABI, number of comorbidities, current smoking, and antidepressant medications, increasing numbers of depressive symptoms were associated with shorter 6-minute walk distance (P <.001), slower usual-pace walking velocity (P =.005), and slower fast-pace walking velocity (P =.005). These relationships were attenuated slightly after additional adjustment for presence versus absence of leg pain on exertion and rest and severity of exertional leg symptoms. CONCLUSIONS: Among men and women with PAD, the prevalence of a clinically significant number of depressive symptoms is high. Greater numbers of depressive symptoms are associated with greater impairment in lower extremity functioning. Further study is needed to determine whether identifying and treating depressive symptoms in PAD is associated with improved lower extremity functioning.

Modifiable patient factors are associated with reverse vein graft occlusion in the era of duplex scan surveillance.

OBJECTIVE: Modifiable patient factors that contribute to graft occlusion may be addressed after surgery. To determine risk factors associated with reverse vein graft (RVG) occlusion, we examined the characteristics and duplex scan surveillance (DS) patterns of patients with RVGs. METHODS: Patients treated with RVG from January 1996 through December 2000 were identified from a prospective registry. The study population consisted of all patients with RVGs performed during the study period with grafts that subsequently occluded. Patients whose grafts remained patent served as age-matched and gender-matched control subjects. The prescribed DS regimen was every 3 months for the first postoperative year and every 6 months thereafter. Early DS failure was defined as having no DS within the first 3 months. Cox proportional hazards analysis was used to compare the two groups. Hazard ratios were calculated. RESULTS: During the study period, 674 patients underwent RVG. Fifty-five patients with occluded RVGs were compared with 118 with patent RVGs. The follow-up period for occluded grafts was 13.40 +/- 12.59 months and for patent grafts was 32.40 +/- 15.61 months. Dialysis therapy, a known hypercoagulable state, continued smoking, and DS failure were independent factors associated with RVG occlusion. The hazards ratio for dialysis was 6.45 (95% CI, 3.07 to 13.51; P <.001), for current smoking was 4.72 (95% CI, 2.5 to 8.85; P <.001), for hypercoagulable state was 2.99 (95% CI, 1.47 to 6.10; P =.003), and for early DS failure was 2.43 (95% CI, 1.29 to 4.59; P =.006). CONCLUSION: Continued smoking and failure to undergo DS within the first three postoperative months are modifiable factors associated with RVG occlusion. Smoking cessation and graft surveillance must be stressed to optimize patency of infrainguinal RVGs.