Normothermia is protective during infrarenal aortic surgery

AbstractPurpose: Mild hypothermia has been suggested to be protective against tissue ischemia during aortic operations. However, recent studies have documented detrimental cardiac effects of hypothermia during a variety of operative procedures. The influence of different warming methods and the impact of hypothermia during standard aortic procedures was assessed. Methods: One hundred patients who underwent repair of infrarenal aortic aneurysms or aortoiliac occlusive disease were prospectively randomized into 2 groups, receiving either a circulating water mattress or a forced air warming blanket. Adjuvant warming methods were standardized. The day before surgery, 48-hour Holter monitors were applied and interpreted by a cardiologist blinded to the treatment. Randomization resulted in equivalent groups with regard to patient history, indications for surgery, body mass index, length of surgery, and fluid requirements. Results: Core temperatures were significantly warmer during surgery (36.3°C ± 0.7°C vs 35.4 ± 0.8°C) and after surgery (36.4°C ± 0.7°C vs 35.6°C ± 0.9°C) in patients with forced air warming (P < .001). The circulating water mattress group had significantly more metabolic acidosis perioperatively (P = .03). Postoperative length of stay, cardiac complications, and death rates were not significantly different. Subgroup analysis of 83 aneurysm patients comparing normothermia with hypothermia (temperature less than 36°C) on arrival to the recovery room identified decreased cardiac output (P = .02), thrombocytopenia (P = .02), elevated prothrombin time (P = .04), and inferior Acute Physiology and Chronic Health Evaluation (APACHE) II scores (P < .001) in the hypothermic group. Holter analysis revealed more sinus tachycardia (ST) segment changes and ventricular tachycardia in hypothermic aneurysm patients (P = .05). Conclusion: Patients treated with forced air blankets had significantly less metabolic acidosis and were kept significantly warmer than those treated with circulating water mattresses. Patients with aneurysms that were kept normothermic had a significantly improved clinical profile, with fewer cardiac events on the Holter recordings. We therefore conclude that (1) normothermia is protective for infrarenal aortic surgical patients; and (2) forced air warming blankets provide improved temperature maintenance compared with circulating water mattresses. (J Vasc Surg 1998;28:984-94.

Prosthetic thigh arteriovenous access: outcome with SVS/AAVS reporting standards

AbstractPurposeDifferences in the reporting methods of results for arteriovenous (AV) access can dramatically affect apparent outcome. To enable meaningful comparisons in the literature, the Society for Vascular Surgery and the American Association for Vascular Surgery (SVS/AAVS) recently published reporting standards for dialysis access. The purpose of the present study was to determine infection rates, patency rates, and possible predictive factors for prosthetic thigh AV access outcomes with the reporting standards of the SVS/AAVS.MethodsA retrospective analysis was performed of all patients who underwent placement of thigh AV access by the Surgical Teaching Service at Greenville Memorial Hospital between 1989 and 2001. Outcomes were determined based on SVS/AAVS Standards for Reports Dealing with AV Accesses. The rate of revision per year of access patency was also determined; this end point more accurately reflects the true cost and morbidity associated with AV access than do patency or infection rates alone.ResultsOne hundred twenty-five polytetrafluoroethylene thigh AV accesses were placed in 100 patients. Nine accesses were excluded from the study, six because there was no patient follow-up and 3 as a result of deaths unrelated to the access procedure and which occurred less than 30 days after access placement. There were six (4%) late access-related deaths. There were 18 (15%) early access failures, related to infection in 14 cases (12%), thrombosis in three cases (2%), and steal in one case (1%). Early failure was more common in patients with diabetes mellitus (P = .036). The primary and secondary functional patency rates were 19% and 54%, respectively, at 2 years. Infection occurred in 48 (41%) accesses. The patency and infection rates were not influenced by patient age, gender, body mass index, or diabetes mellitus. The median number of interventions per year of access patency was 1.68, and this outcome was positively correlated with body mass index (P < .001).ConclusionsProsthetic AV access in the thigh is associated with higher morbidity compared with that reported for the upper extremity, and should be considered only if no upper extremity AV access option is available. Early access failure and the requirement for an increased number of interventions to reestablish and maintain access patency are more common in patients with diabetes mellitus and obesity. The number of interventions per year of access patency is a valuable end point when assessing the outcome of AV access procedures

Preoperative clinical factors predict postoperative functional outcomes after major lower limb amputation: An analysis of 553 consecutive patients

BackgroundDespite being a major determinant of functional independence, ambulation after major limb amputation has not been well studied. The purpose, therefore, of this study was to investigate the relationship between a variety of preoperative clinical characteristics and postoperative functional outcomes in order to formulate treatment recommendations for patients requiring major lower limb amputation.MethodsFrom January 1998 through December 2003, 627 major limb amputations (37.6% below knee amputations, 4.3% through knee amputations, 34.5% above knee amputations, and 23.6% bilateral amputations) were performed on 553 patients. Their mean age was 63.7 years; 55% were men, 70.2% had diabetes mellitus, and 91.5% had peripheral vascular disease. A retrospective review was performed correlating various preoperative presenting factors such as age at presentation, race, medical comorbidities, preoperative ambulatory status, and preoperative independent living status, with postoperative functional endpoints of prosthetic usage, survival, maintenance of ambulation, and maintenance of independent living status. Kaplan-Meier survival curves were constructed and compared by using the log-rank test. Odds ratios (OR) and hazard ratios (HR) with 95% confidence intervals were constructed by using multiple logistic regressions and Cox proportional hazards models.ResultsStatistically significant preoperative factors independently associated with not wearing a prosthesis in order of greatest to least risk were nonambulatory before amputation (OR, 9.5), above knee amputation (OR, 4.4), age >60 years (OR, 2.7), homebound but ambulatory status (OR, 3.0), presence of dementia (OR, 2.4), end-stage renal disease (OR, 2.3), and coronary artery disease (OR, 2.0). Statistically significant preoperative factors independently associated with death in decreasing order of influence included age ≥70 years (HR, 3.1), age 60 to 69 (HR, 2.5), and the presence of coronary artery disease (HR, 1.5). Statistically significant preoperative factors independently associated with failure of ambulation in decreasing order of influence included age ≥70 years (HR, 2.3), age 60 to 69 (HR, 1.6), bilateral amputation (HR, 1.8), and end-stage renal disease (HR, 1.4). Statistically significant preoperative factors independently associated with failure to maintain independent living status in decreasing order of influence included age ≥70 years (HR, 4.0), age 60 to 69 (HR, 2.7), level of amputation (HR, 1.8), homebound ambulatory status (HR, 1.6), and the presence of dementia (HR, 1.6).ConclusionsPatients with limited preoperative ambulatory ability, age ≥70, dementia, end-stage renal disease, and advanced coronary artery disease perform poorly and should probably be grouped with bedridden patients, who traditionally have been best served with a palliative above knee amputation. Conversely, younger healthy patients with below knee amputations achieved functional outcomes similar to what might be expected after successful lower extremity revascularization. Amputation in these instances should probably not be considered a failure of therapy but another treatment option capable of extending functionality and independent living

A comparison of percutaneous transluminal angioplasty versus amputation for critical limb ischemia in patients unsuitable for open surgery

BackgroundPercutaneous transluminal angioplasty (PTA), although not the traditional therapy, seems to be a safe alternative for patients with critical limb ischemia who are believed to be unsuitable candidates for open surgery. However, the efficacy of PTA in this setting has not been analyzed. The purpose of this study was to compare the outcomes of PTA for limb salvage with outcomes of major limb amputation in physiologically impaired patients believed to be unsuitable for open surgery.MethodsFrom a prospective vascular registry, 314 patients (183 underwent amputation, and 131 underwent complex PTA for limb salvage) were identified as physiologically impaired or unsuitable for open surgery. This was defined as having at least one of the following: functional impairment (homebound ambulatory or transfer only), mental impairment (dementia), or medical impairment (two of the following: end-stage renal disease, coronary artery disease, and chronic obstructive pulmonary disease). Patients undergoing PTA were compared with patients undergoing amputation by examining the outcome parameters of survival, maintenance of ambulation, and maintenance of independent living status. Parameters were assessed by using Kaplan-Meier life-table curves (log-rank test and 95% confidence intervals [CIs]) and hazard ratios (HRs) from the Cox model.ResultsPTA resulted in a 12-month limb salvage rate of 63%. Thirty-day mortality was 4.4% for the amputation group and 3.8% for the PTA group. After adjustment for age, race, diabetes, prior vascular procedure, dementia, and baseline functional status, PTA patients had significantly lower rates of ambulation failure (HR, 0.44; P = .0002) and loss of independence (HR, 0.53; P = .025) but had significantly higher mortality (HR, 1.62; P = .006) than amputees. However, when life tables were examined, the maintenance of ambulation advantage lasted only 12 months (PTA, 68.6%; 95% CI, 59.6%-77.7%; amputation, 48%; 95% CI, 40.4%-55.5%) and was not statistically significant at 2 years (62.2% [95% CI, 48.8%-71.5%] and 44% [95% CI, 35.8%-52.2%], respectively). Maintenance of independent living status advantage lasted only 3 months, with no statistically significant difference at 2 years (PTA, 60.5%; 95% CI, 45.4%-75.6%; amputation, 52.6%; 95% CI, 40.4%-64.9%). Although mortality was high in both cohorts, patients who underwent amputation had a survival advantage for all time intervals examined (at 2 years: PTA, 29%; 95% CI, 19.9%-38.1%; amputation, 48.1%; 95% CI, 39.2%-56.9%).ConclusionsPatients who present with critical limb ischemia and physiologic impairments that preclude open surgery seem to have comorbidities that blunt any functional advantage achieved after PTA for limb salvage. PTA in this setting affords very little benefit compared with amputation alone

The LEGS Score: A Proposed Grading System to Direct Treatment of Chronic Lower Extremity Ischemia

OBJECTIVE: To prospectively compare the Lower Extremity Grading System (LEGS)-derived “recommended treatment” to the actual treatment performed and to analyze LEGS intergrader scoring consistency by comparing blinded scoring results between physician graders. SUMMARY BACKGROUND DATA: Due to technical advances and the increased medical complexity of the aging population, the most appropriate treatment for chronic lower extremity ischemia—open surgery versus endovascular—is again in flux. In an attempt to standardize management, the LEGS score, based on the best available outcomes data, was devised by the physicians of an established vascular service. METHODS: From March to June 2002, all chronically ischemic lower extremities that met standard indications for revascularization were prospectively enrolled and independently graded with the LEGS score by an “endovascular surgeon” and an “open surgeon” for comparative analysis. The results were then blindly evaluated to determine whether the LEGS-derived “recommended treatment” agreed with the actual treatment rendered and to assess for intergrader consistency. Agreement was assessed using kappa statistical analysis. RESULTS: Of the 137 presenting limbs (mean patient age 66.4 yo; 43% claudication, 57% limb-threatening ischemia), 107 were treated (65% endovascular, 30% open surgery, 5% amputation), 16 were pending treatment, and 14 were not treated because of patient refusal (n = 13) or death (n = 1). The LEGS score predicted the actual or offered clinical treatment in 90% of cases. The LEGS score comparison between physician graders resulted in identical “recommended treatment” in 116 of 128 cases for a 90.6% agreement. CONCLUSIONS: A reproducible scoring system to guide the treatment of patients with chronic lower extremity ischemia is possible. While systems like the LEGS score may have potential clinical application, their use as a treatment standardization tool for future prospective outcomes comparisons between open and endovascular surgery will be essential