Anton N. Sidawy

Revascularization of a Specific Angiosome for Limb Salvage: Does the Target Artery Matter?

Ischemic wounds of the lower extremity can fail to heal despite successful revascularization. The foot can be divided into six anatomic regions (angiosomes) fed by distinct source arteries arising from the posterior tibial (three), anterior tibial (one), and peroneal (two) arteries. This study investigated whether bypass to the artery directly feeding the ischemic angiosome had an impact on wound healing and limb salvage. Retrospective analysis was performed for 52 nonhealing lower extremity wounds (48 patients) requiring tibial bypass over a 2-year period. Preoperative arteriograms were reviewed to determine arterial anatomy relative to each wounds specific angiosome and bypass anatomy. Patients were divided into two groups; direct revascularization (DR, bypass to the artery directly feeding the ischemic angiosome) or indirect revascularization (IR, bypass unrelated to the ischemic angiosome). Wound outcome was analyzed with regard to the endpoints of complete healing, amputation, or death unrelated to the wound. Time to healing was also noted for healed wounds. Based on preoperative arteriography, 51% (n = 27) of the wounds received DR to the ischemic angiosome, while 49% (n = 25) underwent IR. There were no statistically significant differences in the comorbidities of the two groups. Revascularization was via tibial bypass using the saphenous vein (n = 34, 65%) or polytetrafluoroethylene with a distal vein patch (n = 18, 35%). Bypasses were performed to the anterior tibial (n = 22, 42%), posterior tibial (n = 17, 33%), or peroneal (n = 13, 25%) arteries based on the surgeons judgment. One bypass failed in the perioperative period and was excluded from the analysis. The remaining bypasses were patent at the time of wound analysis. Due to a 17% mortality rate during follow-up, 43 wounds were available for endpoint analysis. This analysis demonstrated that 77% of wounds (n = 33) progressed to complete healing and 23% of wounds (n = 10) failed to heal with resultant amputation. In the DR group, there was 91% healing with a 9% amputation rate. In the IR group, there was 62% healing with a 38% amputation rate (p = 0.03). In those wounds that did heal, total time to healing was not significantly different--DR 162.4 days versus IR 159.8 days (p = 0.95). Revascularization plays a crucial role in the treatment of ischemic lower extremity wounds. We believe that direct revascularization of the angiosome specific to the anatomy of the wound leads to a higher rate of healing and limb salvage. Although many factors must be considered in choosing the target artery for revascularization, consideration should be given to revascularization of the artery directly feeding the ischemic angiosome.

Complications of arteriovenous hemodialysis access: Recognition and management

English language citations reporting complications of arteriovenous access for hemodialysis are critically reviewed and discussed. Venous hypertension, arterial steal syndrome, and high-output cardiac failure occur as a result of hemodynamic alterations potentiated by access flow. Uremic and diabetic neuropathies are common but may obfuscate recognition of potentially correctable problems such as compression or ischemic neuropathy. Mechanical complications include pseudoaneurysm, which may develop from a puncture hematoma, degeneration of the wall, or infection. Dysfunctional hemostasis, hemorrhage, noninfectious fluid collections, and access-related infections are, in part, manifestations of the adverse effects of uremia on the function of circulating hematologic elements. Impaired erythropoiesis is successfully managed with hormonal stimulation; perhaps, similar therapies can be devised to reverse platelet and leukocyte dysfunction and reduce bleeding and infectious complications.

Impact of Renal Insufficiency on Short-Term Morbidity and Mortality after Lower Extremity Revascularization: Data from the Department of Veterans Affairs’ National Surgical Quality Improvement Program

Few data are available on the impact of renal insufficiency on short-term operative outcomes after lower extremity surgical revascularization. We used prospectively collected data from the Department of Veterans Affairs National Surgical Quality Improvement Program (NSQIP) to explore the association with renal dysfunction of adverse outcomes occurring within 30 d of lower extremity surgical revascularization in a cohort of all patients undergoing at least one lower extremity surgical revascularization from 1/1/94 to 9/30/01 (n = 18,217). Even moderate renal insufficiency (estimated GFR 30-59cc/min/1.73m(2)) was associated with an increased incidence of postoperative death (adjusted odds ratio (OR) 1.44, 95% confidence interval (CI), 1.17 to 1.77, P = 0.001), cardiac arrest (OR 1.43, CI 1.09 to 1.88, P = 0.011), myocardial infarction (OR 1.68, 1.39 to 2.16, P < 0.001), unplanned intubation (OR 1.69, CI 1.39 to 2.07, P < 0.001) and prolonged intubation (OR 1.57, CI 1.28 to 1.94, P < 0.001) within 30 d of lower extremity revascularization. However, the incidence of wound infection and graft failure requiring return to the operating room did not appear to be substantially higher in this group. Our data also show that patients with renal insufficiency undergoing revascularization were more likely to require distal procedures and to present with limb-threatening infection compared to those with normal renal function. Efforts to improve pre-and post-operative care in patients with renal insufficiency undergoing lower extremity revascularization should take into account the increased incidence of postoperative death and cardiopulmonary complications in this group in addition to more traditional concerns about operative site complications. Further studies are needed to explore reasons for the higher rate of limb-threatening infection in patients with renal insufficiency undergoing revascularization.

Insulin action enhancement normalizes brachial artery vasoactivity in patients with peripheral vascular disease and occult diabetes

PURPOSEnBrachial artery vasoactivity (BAVA) evaluation is a reliable, noninvasive method of assessing arterial endothelial function in vivo. We previously have shown that patients with peripheral vascular disease (PVD) and occult diabetes have abnormal BAVA results when fasting and after oral glucose intake during oral glucose tolerance test (OGTT). Troglitazone is an oral hypoglycemic agent that enhances the action of insulin. The effect of troglitazone on BAVA in patients with occult diabetes and PVD is not known.nnnMETHODSnPatients with PVD, normal fasting glucose levels, and abnormal OGTT results were identified. With a duplex ultrasound scan, BAVA was evaluated by measuring the brachial artery (BA) flow (in millimeters per minute) before and after 5 minutes of BA occlusion during fasting and at 30 minutes, 1 hour, and 2 hours after the administration of 75 g of glucose during OGTT. Troglitazone therapy (400 mg/day) was begun, and the BAVA evaluation was repeated after 2 and 4 months. These results were compared with the results of the control group who had normal fasting glucose levels, normal OGTT results, and no evidence of PVD. A paired t test was used to compare the BA flow before and after BA occlusion, with a P value of less than.05 considered significant.nnnRESULTSnThe control group had a normal hyperemic response with a significantly increased BA flow after 5 minutes of BA occlusion during fasting and at all stages of the OGTT. The occult diabetic group had an abnormal response to hyperemia before the treatment with troglitazone and showed little change in flow after BA occlusion. After 2 months of troglitazone therapy, BAVA results improved after oral glucose intake but not during fasting. After 4 months, BAVA results normalized both while fasting and after oral glucose intake during the OGTT.nnnCONCLUSIONnPatients with occult diabetes and PVD have impaired BAVA, which normalizes after treatment with troglitazone. Insulin-action enhancers may slow the progression of PVD in patients with diabetes by improving endothelial cell function. Agents that are aimed at enhancing the action of insulin may have an advantage over the other traditional therapies for diabetes.

Autogenous versus prosthetic vascular access for hemodialysis: a systematic review and meta-analysis.

OBJECTIVESnThe autogenous arteriovenous access for chronic hemodialysis is recommended over the prosthetic access because of its longer lifespan. However, more than half of the United States dialysis patients receive a prosthetic access. We conducted a systematic review to summarize the best available evidence comparing the two accesses types in terms of patient-important outcomes.nnnMETHODSnWe searched electronic databases (MEDLINE, EMBASE, Cochrane CENTRAL, Web of Science and SCOPUS) and included randomized controlled trials and controlled cohort studies. We pooled data for each outcome using a random effects model to estimate the relative risk (RR) and its associated 95% confidence interval (CI). We estimated inconsistency caused by true differences between studies using the I(2) statistic.nnnRESULTSnEighty-three studies, of which 80 were nonrandomized, met eligibility criteria. Compared with the prosthetic access, the autogenous access was associated with a significant reduction in the risk of death (RR, 0.76; 95% CI, 0.67-0.86; I(2) = 48%, 27 studies) and access infection (RR, 0.18; 95% CI, 0.11-0.31; I(2) = 93%, 43 studies), and a nonsignificant reduction in the risk of postoperative complications (hematoma, bleeding, pseudoaneurysm and steal syndrome, RR 0.73; 95% CI, 0.48-1.16; I(2) = 65%, 31 studies) and length of hospitalization (pooled weighted mean difference -3.8 days; 95% CI, -7.8 to 0.2; P = .06). The autogenous access also had better primary and secondary patency at 12 and 36 months.nnnCONCLUSIONnLow-quality evidence from inconsistent studies with limited protection against bias shows that autogenous access for chronic hemodialysis is superior to prosthetic access.

Predictors of lower extremity arterial injury after total knee or total hip arthroplasty.

OBJECTIVEnLower extremity arterial injury is a rare complication following total knee (TKA) or total hip arthroplasty (THA). To date, no multi-institutional study has identified preoperative factors that may portend increased risk for these injuries. We queried a large clinical database for the incidence and predictors of arterial injury and/or compromise following lower extremity arthroplasty.nnnMETHODSnProspectively collected preoperative and postoperative data by the National Surgical Quality Improvement Program (NSQIP) of the Veterans Affairs Medical Centers were analyzed. All patients from 1996 to 2003 in the NSQIP database who underwent TKA or THA were identified via CPT codes. NSQIP defined, 30-day, postoperative outcomes were analyzed. Data were compared using bivariable analysis, as well as limited multivariable logistic regression.nnnRESULTSnA total of 41,633 arthroplasties (24,029 TKA, 2077 redo-TKA, 13,494 THA, 2033 redo-THA) were identified in the NSQIP database. A total of 34 (0.08%) lower extremity arterial injuries were recognized (0.08% TKA, 0.19% redo-TKA, 0.04% THA, 0.20% redo-THA). Eighteen injuries were repaired on the same day of surgery (seven intraop, 11 postop), eight between postoperative days 1 and 5, and 8 between days 6 and 30. Only two patients underwent lower extremity amputation (overall limb loss rate of 5.9% of patients who had arterial injury). Statistically significant predictors of lower extremity arterial injury identified on logistic regression analysis included redo procedure (odds ratio [OR] 2.7, 95% confidence interval [CI] 1.2-6.0, P = .013) and African American race (OR 2.5, 95% CI 1.2-5.3, P = .02).nnnCONCLUSIONnLower extremity arterial injury was exceedingly rare after total knee or total hip arthroplasty. There is an increased incidence in African American patients and those undergoing redo arthroplasty. Among patients who sustain vascular injury, excellent limb salvage rates can be achieved with close postoperative surveillance to achieve early detection and repair of injuries.

Effect of chronic renal insufficiency on outcomes of carotid endarterectomy

OBJECTIVEnConflicting data exist regarding the effect of chronic renal insufficiency (CRI) on carotid endarterectomy (CEA) outcomes. A large database was used to analyze the effect of CRI, defined by glomerular filtration rate (GFR), as an independent risk factor of CEA.nnnMETHODSnProspectively collected data regarding CEAs performed at 123 Veterans Affairs Medical Centers as part of the National Surgical Quality Improvement Program were retrospectively analyzed. Renal function was used to divide patients into three CRI groups: normal or mild (control; GFR >/=60 mL/min/1.73 m(2)), moderate (GFR 30 to 59), and severe (GFR <30). Bivariate analysis and multivariate logistic regression were used to characterize risk factors and their associations with 30-day morbidity and mortality.nnnRESULTSnBetween Jan 1, 1996, and Dec 31, 2003, 22,080 patients underwent CEA. Patients missing creatinine levels, already dialysis-dependent, or in acute renal failure just before surgery were excluded. This left 20,899 available for analysis, of which 13,965 had a GFR of >/=60, 6,423 had a GFR of 30 to 59, and 511 had a GFR of <30. The incidence of neurologic complications did not differ significantly (control, 1.7%; moderate CRI, 1.9%; severe CRI, 2.7%). The moderate CRI group experienced significantly more cardiac events (1.7% vs 0.9% for controls, P < .001). This remained predictive in the multivariate model even adjusting for all other risk factors (adjusted odds ratio [AOR], 1.6; 95% confidence interval [CI], 1.1-2.3; P = .009). The moderate CRI group also had higher rates of pulmonary complications (2.1% vs 1.3% control; P < .001; AOR, 1.3; 95% CI, 1.0-1.7; P = .031) but not 30-day mortality (P = .269). Those with severe CRI had a much higher mortality (3.1% vs 1.0% control, P < .001), which remained significant in the multivariate model (AOR, 2.7; 95% CI, 1.6-4.8; P < .001).nnnCONCLUSIONnAlthough impaired renal function does not independently increase the risk of neurologic or infectious complications, CRI is a significant negative independent risk factor in predicting other outcomes after CEA. Patients with moderate CRI (GFR, 30-59 mL/min/1.73 m(2)) are at increased risk for cardiac and pulmonary morbidity, but not death, and those with severe CRI (GFR <30 mL/min/1.73 m(2)) have a much higher operative mortality. Patients with CRI should be carefully evaluated before CEA to optimize existing cardiac and pulmonary disease. Understanding this increased risk may assist the surgeon in preoperative counseling and perioperative management.

Renal Insufficiency and Use of Revascularization among a National Cohort of Men with Advanced Lower Extremity Peripheral Arterial Disease

Although peripheral arterial disease is prevalent in patients with renal insufficiency, little is known about how the disease is managed in this patient group. The management of advanced limb ischemia was examined in a large cohort of male veterans (n = 6227). Patients were classified according to whether they underwent lower extremity revascularization, amputation, or no procedure within the first 6 mo after their first diagnosis of critical limb ischemia, defined as ischemic rest pain, ulceration, or gangrene. The association of renal insufficiency with revascularization and the association of management strategy with mortality within 1 yr of cohort entry were measured. Within 6 mo of initial diagnosis of critical limb ischemia, 39% of patients underwent lower extremity revascularization, 27% underwent major amputation, and 34% did not undergo either procedure. Patients with an estimated GFR 30 to 59 (adjusted odds ratio [OR] 0.84; 95% confidence interval [CI] 0.72 to 0.96), 15 to 29 ml/min per 1.73 m2 (OR 0.47; 95% CI 0.35 to 0.65), 15 ml/min per 1.73 m2 not on dialysis (OR 0.32; 95% CI 0.16 to 0.62), and dialysis patients (OR 0.62; 95% CI 0.47 to 0.84) were less likely to undergo revascularization than those with an estimated GFR > or = 60 ml/min per 1.73 m2. At all levels of renal function, mortality risk was lowest for patients who underwent revascularization. Patients with critical limb ischemia and concomitant renal insufficiency are less likely to be treated with revascularization. However, among patients with renal insufficiency, mortality is lowest for patients who receive a revascularization. Further studies are needed to determine the optimal care for this high-risk patient group.

Quality of life of patients with Takayasu’s arteritis

OBJECTIVEnTakayasus arteritis (TA) is a chronic immune vasculitis that causes inflammation of the aorta and its branches and is clinically characterized by exacerbations and remissions. This study examined the quality of life (QoL) of patients with TA using the Medical Outcomes Study Short Form 36 (SF-36) Health Survey, a validated health related QoL questionnaire.nnnMETHODSnQuestionnaires that included the SF-36 and demographic related variables were mailed to 392 patients enrolled in the Takayasus Arteritis Research Association. Raw SF-36 scores, as well as Physical Health Summary (PHS) and Mental Health Summary (MHS) scores, were calculated according to standard protocols. Data were analyzed for predictors of superior QoL using univariate and stepwise logistic regression analysis. SF-36 scores were also compared with those of other chronic diseases associated with peripheral vascular disease (PVD) published in the literature. Results are reported as mean +/- standard error of the mean.nnnRESULTSnA total of 158 patients (144 women, 14 men) with average age of 42.2 +/- 1.1 years responded to the questionnaire. Mean onset of symptoms occurred at 30.5 +/- 1.2 years, with a mean age at diagnosis of 34.7 +/- 1.2, and a median of four doctors were seen before diagnosis. The group underwent 299 TA-related surgical procedures (1.9 +/- 0.3), including coronary (38%), carotid (35%), upper extremity (30%), and lower extremity (26%) revascularization. PHS and MHS summary scores (39.2 +/- 1.0 and 44.5 +/- 1.0, respectively) were worse than mean scores for an age-matched healthy population as well as nationally reported scores for diabetes mellitus, hypertension, and coronary artery disease (all P < .0001). Multivariate predictors of better physical QoL were younger age (P = .003) and remission of the disease (P = .0002). The use of immunomodulating medications was associated with inferior physical QoL (P = .02). The sole predictor of better mental QoL was remission of disease (P = .002).nnnCONCLUSIONnTA is a rare disease with profound consequences on QoL. Scores for physical and mental health are worse compared with many other chronic diseases associated with PVD. Superior physical QoL is seen in younger patients, whereas inferior physical QoL is encountered in those who take immunomodulating medications. Because the only factor to influence positively both physical and mental QoL is disease remission, every effort should be directed to attenuate disease activity.

Surveillance of arteriovenous hemodialysis access: A systematic review and meta-analysis

OBJECTIVESnHemodialysis centers regularly survey arteriovenous (AV) accesses for signs of dysfunction. In this review, we synthesize the available evidence to determine to what extent proactive vascular access monitoring affects the incidence of AV access thrombosis and abandonment compared with clinical monitoring.nnnMETHODSnWe searched electronic databases (MEDLINE, EMBASE, Cochrane CENTRAL, Web of Science, and SCOPUS) and sought references from experts, bibliographies of included trials, and articles that cited included studies. Two reviewers independently assessed trial quality and extracted data. We used random effects meta-analysis to estimate the pooled relative risk (RR) and 95% confidence interval (CI) across studies and conducted subgroup analyses to explain heterogeneity. The I(2) statistic was used to assess heterogeneity of treatment effect among trials.nnnRESULTSnNine studies (1363 patients) compared a strategy of surveillance vs clinical monitoring. A vascular intervention to maintain or restore patency was provided to both groups if needed. Surveillance followed by intervention led to a nonsignificant reduction of the risk of access thrombosis (RR, 0.82; 95% CI, 0.58-1.16; I(2) = 37%) and access abandonment (RR, 0.80; 95% CI, 0.51-1.25; I(2) = 60%). Three studies (207 patients) compared the effect of vascular interventions vs observation in patients with abnormal surveillance result. Vascular interventions after an abnormal AV access surveillance led to a significant reduction of the risk of access thrombosis (RR, 0.53; 95% CI, 0.36-0.76) and a nonsignificant reduction of the risk of access abandonment (RR, 0.76; 95% CI, 0.43-1.37).nnnCONCLUSIONnVery low quality evidence yielding imprecise results suggests a potentially beneficial effect of AV access surveillance followed by interventions to restore patency. This inference, however, is weak and will require randomized trials of AV access surveillance vs clinical monitoring for rejection or confirmation.