Surveillance and Management of Troponin Elevation after Vascular Surgery.

BACKGROUND: Postopertive troponin elevation may occur without typical or atypical cardiac symptoms and is associated with an increased 30-day morbidity and mortality. The objective of the study was to implement a quality improvement initiative of postoperative troponin surveillance algorithm aimed at intensifying medical management after vascular surgery. METHODS: We conducted a single-center study of postoperative troponin surveillance after vascular surgery (n = 201) at a tertiary care, academic medical center from January to December 2016. Troponin surveillance was performed on postoperative days 1-3 after carotid endarterectomy, endovascular aortic repair, infrainguinal bypass, open abdominal aortic aneurysm repair, peripheral vascular intervention, and suprainguinal bypass, regardless of cardiac symptoms. Patients with troponin I elevation (>0.034 ng/mL) were managed with a treatment algorithm which included single or dual antiplatelet (AP) agent, high-intensity statin therapy, smoking cessation consultation, and outpatient cardiology consultation and stress testing. Patients with troponin elevation ≥1.0 ng/mL received inpatient cardiology consultation. We assessed adherence to the protocol for intensification of best medical therapy defined as high-dose statin therapy, increase in AP therapy, and smoking cessation consultation according to the established algorithm. RESULTS: Troponin elevation was recorded in 17% (34/201) of patients and was associated with cardiac symptoms in 8 patients (24%), while 26 (76%) patients had an asymptomatic abnormal troponin on postoperative surveillance. One patient was excluded due to death immediately after SUPRA, resulting in 200 patients. Troponin elevation ≥1.0 ng/mL occurred in 11 asymptomatic patients (5.5%). Any intensification of medical therapy was instituted in 76% of patients with elevated troponin and included high-intensity statin therapy (58%), increase in AP therapy (18%), and smoking cessation consultation (66%). Once an elevated troponin level was recognized, 52% of our patients received cardiology consultation with an increased likelihood (100%) in patients with troponin ≥1 ng/mL (P < 0.001). Adherence to outpatient stress testing was 66%. Intensification of medical therapy was not significantly different between patients with abnormal troponin values, >0.034-1.0 (n = 23) versus ≥1.0 ng/mL (n = 10); statin therapy (P = 1.0), AP (P = 0.34), and smoking cessation (P = 1.0). One-year mortality was higher in patients with postoperative troponin elevation than those with normal postoperative troponin levels (12% vs. 2.4%; P = 0.03). CONCLUSIONS: Routine postoperative troponin surveillance results in intensification of statin therapy in patients with asymptomatic troponin elevation. Further study is needed to determine if this approach reduces long-term cardiovascular morbidity and mortality.

Postoperative opioid prescribing patterns and use after vascular surgery.

The aim of this study was to assess postoperative opioid prescribing patterns, usage, and pain control after common vascular surgery procedures in order to develop patient centered best-practice guidelines. We performed a prospective review of opioid prescribing after seven common vascular surgeries at a rural, academic medical center from December 2016 to July 2017. A standardized telephone questionnaire was prospectively administered to patients ( n = 110) about opioid use and pain management perceptions. For comparison we retrospectively assessed opioid prescribing patterns ( n = 939) from July 2014 to June 2016 normalized into morphine milligram equivalents (MME). Prescribers were surveyed regarding opioid prescription attitudes, perceptions, and practices. Opioids were prescribed for 78% of procedures, and 70% of patients reported using opioid analgesia. In the prospective group, the median MMEs prescribed were: VEIN (31, n = 16), CEA (40, n = 14), DIAL (60, n = 17), EVAR (108, n = 8), INFRA (160, n = 16), FEM TEA (200, n = 11), and OA (273, n = 4). The median proportion of opioids used by patients across all procedures was only 30% of the amount prescribed across all procedures (range 14-64%). Patients rated the opioid prescribed as appropriate (59%), insufficient (16%), and overprescribed (25%), and pain as very well controlled (47%), well controlled (47%), poorly controlled (4%), and very poorly controlled (2%). In conclusion, we observed significant variability in opioid prescribing after vascular procedures. The overall opioid use was substantially lower than the amount prescribed. These data enabled us to develop guidelines for opioid prescribing practice for our patients.

Prospective Study of Postoperative Glycemic Control with a Standardized Insulin Infusion Protocol after Infrainguinal Bypass and Open Abdominal Aortic Aneurysm Repair.

BACKGROUND: The aim of this study is to examine the effect of moderate postoperative glycemic control in diabetic and nondiabetic patients undergoing infrainguinal bypass (INFRA) or open abdominal aortic aneurysm (OAAA) repair. METHODS: In a single center prospective study, we investigated postoperative glycemic control using a standardized insulin infusion protocol after elective INFRA bypass (n = 53, 62%) and OAAA repair (n = 33, 38%) between January 2013 and March 2015. The primary end point was optimal glycemic control, defined as having ≥85% of blood glucose values within the 80-150 mg/dL target range. Suboptimal glycemic control was defined as <85% of blood glucose values within the blood glucose target range. Secondary end points included in-hospital and 30-day surgical site infection (SSI) rates, composite adverse events, length of stay (LOS), and hospital cost. RESULTS: Optimal glycemic control was achieved more commonly after OAAA repair than INFRA bypass (85% vs. 64%, P = 0.04). Moderate hypoglycemia (<70 mg/dL) was observed in 32 (37%) patients, while severe hypoglycemia (<50 mg/dL) was observed in 6 (7%) patients. SSI at 30 days was more common after INFRA bypass (n = 15, 29%) than OAAA repair (n = 2, 6%) (P = 0.01). In-hospital (6% vs. 6%, P = 1.0) and 30-day (24% vs. 22%, P = 1.0) SSI rates were similar for optimal versus suboptimal glycemic control patients after INFRA bypass. In-hospital (4% vs. 0%, P = 1.0) and 30-day (4% vs. 0%, P = 1.0) SSI rates were similar for optimal versus suboptimal glycemic control patients after OAAA repair. The percentage of blood glucose > 250 mg/dL was similar for patients with and without SSI (3% vs. 2%, P = 0.36). Adverse cardiac and pulmonary events after INFRA bypass were similar between groups (9% vs. 21%, P = 0.23; 0% vs. 5%, P = 0.36, respectively). Adverse cardiac and pulmonary events after OAAA repair were similar between groups (2% vs. 0%, P = 1.0; 4% vs. 0%, P = 1.0, respectively). Mean LOS was significantly lower in patients with optimal glycemic control after INFRA bypass (4.2 vs. 7.3 days, P = 0.02). Mean LOS was similar after OAAA repair for patients with optimal and suboptimal control (5.8 vs. 6.4 days, P = 0.46). Inpatient hospital costs after INFRA bypass were lower for the group with optimal (median $25,012, interquartile range [IQ] range $21,726-28,331) versus suboptimal glycemic control (median $28,944, IQ range 24,773-41,270, P = 0.02). CONCLUSIONS: Postoperative hyperglycemia is common after INFRA bypass and OAAA repair and can be effectively ameliorated with an insulin infusion protocol. The protocol was low risk with reduced LOS and cost after INFRA bypass. Complications including SSI were not reduced in patients with optimal perioperative glycemic control.

An Algorithm to Analyze Cost Heterogeneity using Counterfactual Scenarios in Endovascular versus Open Repair of Abdominal Aortic Aneurysm: Predicting Costs for Subsequent Patients.

Objectives: We examined patient-specific predictors of high cost for endovascular (EVAR) and open (OPEN) repair of abdominal aortic aneurysm (AAA). Methods: Vascular Study Group of Northern New England data specific to Fletcher Allen Health Care were merged with cost data from the same source. We retrospectively analyzed 389 elective AAA repairs (230 EVAR, 159 OPEN) between 2003 and 2011 to determine clinical characteristics that contribute to membership in the upper quartile of cost (UQC) versus the remaining three quartiles. For the purpose of this exercise, it was assumed that clinical outcomes were equally good with EVAR versus OPEN repair. Results: Significant predictors of UQC for OPEN repair procedures were: history of treated chronic obstructive pulmonary disease (COPD), previous bypass surgery, transfer from hospital and age >70 (area under receiver operating curve [ROC] = 0.726). Predictors of UQC for EVAR were: presence of iliac aneurysm(s), coronary artery bypass graft surgery or percutaneous transluminal coronary angioplasty within the past 5 years, ejection fraction ≤30%, absence of beta blockers, creatinine ≥1.5mg/dL, and current use of tobacco (area under ROC = 0.784). The mean length of stay for EVAR and OPEN repair were 2.22 and 8.55 days, respectively. Costs for EVAR and OPEN repair were $32,656 (standard error of the mean [SEM] $591) and $28,183 (SEM $1,571), respectively. Conclusions: Certain risk factors at the individual patient level are predictive of UQC. Under such circumstances, it is our expectation that such algorithms may be used to select the most cost-efficient treatment.

Shared quality data are associated with increased protamine use and reduced bleeding complications after carotid endarterectomy in the Vascular Study Group of New England.

OBJECTIVE: The goal of this study was to evaluate whether protamine usage after carotid endarterectomy (CEA) increased within the Vascular Study Group of New England (VSGNE) in response to studies indicating that protamine reduces bleeding complications associated with CEA without increasing the risk of stroke. METHODS: We reviewed 10,059 CEAs, excluding concomitant coronary bypass, performed within the VSGNE from January 2003 to July 2012. Protamine use and reoperation for bleeding were evaluated monthly using statistical process control. Twelve centers and 77 surgeons entering the VSGNE between 2003 and 2008 were classified as original participants, and 14 centers and 60 surgeons joining after May 2009 were considered new. Protamine use for surgeons was categorized as rare (<10%), selective (10%-80%), or routine (>80%). Outcome measures were in-hospital reoperation for bleeding, postoperative myocardial infarction (POMI), and stroke or death. RESULTS: Two significant increases occurred in protamine use for all VSGNE centers over time. From 2003 to 2007, the protamine rate remained stable at 43%. In 2008, protamine usage increased to 52% (P < .01), coincident with new centers joining the VSGNE. Protamine usage then increased to 62% in 2010 (P < .01), shortly after the presentations of the data showing a benefit of protamine. This effect was due to 10 surgeons in the original VSGNE centers who increased their usage of protamine: six surgeons from rare use to selective use and four surgeons to routine use. Reoperation for bleeding was reduced by 0.84% (relative risk reduction, 57.2%) in patients who received protamine (0.6% vs 1.44%; P < .001). There were no differences in POMI (1.1% vs 1.09%) or stroke or death (1.1% vs 1.03%) between protamine treated and untreated patients, respectively. Reoperation for bleeding was decreased for surgeons who used protamine routinely (0.5%; P < .001) compared with selective (1.4%) and rare users (1.5%) of protamine. There were no differences in POMI (0.9%, 1.2%, 1.1%; P = .720) and stroke or death rates (1.0%, 1.2%, 1.0%; P = .656) for rare, selective, and routine users of protamine. CONCLUSIONS: Protamine use increased over time by VSGNE surgeons, most significantly after the presentations of VSGNE-derived data showing the benefit of protamine, and was associated with a decrease in reoperation for bleeding. Improvements in processes of care and outcomes can be achieved in regional quality groups by sharing safety and efficacy data.

Variation in smoking cessation after vascular operations.

OBJECTIVE: Smoking is the most important modifiable risk factor for patients with vascular disease. The purpose of this study was to examine smoking cessation rates after vascular procedures and delineate factors predictive of postoperative smoking cessation. METHODS: The Vascular Study Group of New England registry was used to analyze smoking status preoperatively and at 1 year after carotid endarterectomy, carotid artery stenting, lower extremity bypass, and open and endovascular abdominal aortic aneurysm repair between 2003 and 2009. Of 10,734 surviving patients after one of these procedures, 1755 (16%) were lost to follow-up and 1172 (11%) lacked documentation of their smoking status at follow-up. The remaining 7807 patients (73%) were available for analysis. Patient factors independently associated with smoking cessation were determined using multivariate analysis. The relative contribution of patient and procedure factors including treatment center were measured by χ-pie analysis. Variation between treatment centers was further evaluated by calculating expected rates of cessation and by analysis of means. Vascular Study Group of New England surgeons were surveyed regarding their smoking cessation techniques (85% response rate). RESULTS: At the time of their procedure, 2606 of 7807 patients (33%) were self-reported current smokers. Of these, 1177 (45%) quit within the first year of surgery, with significant variation by procedure type (open abdominal aortic aneurysm repair, 50%; endovascular repair, 49%; lower extremity bypass, 46%; carotid endarterectomy, 43%; carotid artery stenting, 27%). In addition to higher smoking cessation rates with more invasive procedures, age >70 years (odds ratio [OR], 1.90; 95% confidence interval [CI], 1.30-2.76; P < .001) and dialysis dependence (OR, 2.38; 95% CI, 1.04-5.43; P = .04) were independently associated with smoking cessation, whereas hypertension (OR, 1.23; 95% CI, 1.00-1.51; P = .051) demonstrated a trend toward significance. Treatment center was the greatest contributor to smoking cessation, and there was broad variation in smoking cessation rates, from 28% to 62%, between treatment centers. Cessation rates were higher than expected in three centers and significantly lower than expected in two centers. Among survey respondents, 78% offered pharmacologic therapy or referral to a smoking cessation specialist, or both. The smoking cessation rate for patients of these surgeons was 48% compared with 33% in those who did not offer medications or referral (P < .001). CONCLUSIONS: Patients frequently quit smoking after vascular surgery, and multiple patient-related and procedure-related factors contribute to cessation. However, we note significant influence of treatment center on cessation as well as broad variation in cessation rates between treatment centers. This variation indicates an opportunity for vascular surgeons to impact smoking cessation at the time of surgery.

Evaluation of simulation-based training model on vascular anastomotic skills for surgical residents.

INTRODUCTION: Reduced work hours and concerns over patient safety have encouraged surgical educators to find methods to advance resident skills more efficiently. Simulation provides the opportunity to improve technical surgical skills outside the operating room. We hypothesized that practice on surgical task simulators would improve residents' technical performance of vascular anastomotic technique. METHODS: Senior general surgery residents at an academic medical center completed pretests and posttests on 3 vascular surgery simulators: femoral-popliteal bypass, carotid endarterectomy, and abdominal aortic aneurysm repair. The initial training sessions began with a 15-minute instructional video on how to perform the procedures, followed by supervised sessions in anastomotic technique with attending vascular surgeons. Initial individual sessions were videotaped as a pretest, and the final attempt was videotaped as the posttest. Each test was evaluated by a single experienced attending vascular surgeon blinded to the examinees. Anastomoses were graded using a performance rating and a modified objective structured assessment of technical skill rating. Results were analyzed using mixed model P values. RESULTS: The residents showed statistically significant improvement between the pretest and the posttest in both their performance rating (1.9 vs. 2.4, P = 0.02) and the objective structured assessment of technical skill (2.6 vs. 3.1, P = 0.01), as well as in most subsets of each assessment scale. CONCLUSIONS: We conclude that practice using simulated anastomotic models leads to measurable improvement in vascular anastomotic technique in senior general surgery residents.

The impact of diabetes on postoperative outcomes following lower-extremity bypass surgery.

OBJECTIVE: The effect of diabetes type (noninsulin dependent vs insulin dependent) on outcomes after lower-extremity bypass (LEB) has not been clearly defined. Therefore, we analyzed associations between diabetes type and outcomes after LEB in patients with critical limb ischemia. METHODS: We performed a retrospective analysis of 1977 infrainguinal LEB operations done for critical limb ischemia between 2003 and 2010 within the Vascular Study Group of New England. Patients were categorized as nondiabetic (ND), noninsulin-dependent diabetic (NIDD), or insulin-dependent diabetic (IDD) based on their preoperative medication regimen. Our main outcome measures were in-hospital mortality and major adverse events (MAEs)--a composite outcome, including myocardial infarction, dysrhythmia, congestive heart failure, wound infection, renal insufficiency, and major amputation. We compared crude and adjusted rates of mortality and MAEs using logistic regression across diabetes categories. RESULTS: Overall, 41% of patients were ND, 28% were NIDD, and 31% were IDD. Crude rates of in-hospital mortality were similar across these groups (1.7% vs 3.1% vs 2.1%; P = .211). Adjusted analyses accounting for differences in patient characteristics showed that diabetes is not associated with increased risk of in-hospital mortality. However, type of diabetes was associated with a higher risk of MAEs in both crude (15.1% for ND; 21.1% for NIDD; and 25.2% for IDD; P < .001) and adjusted analyses (odds ratio for NIDD, 1.41; 95% confidence interval, 1.2-1.7; odds ratio for IDD, 1.53; 95% confidence interval, 1.3-1.8). CONCLUSIONS: Diabetes is a significant contributor to the risk of postoperative complications after LEB surgery, and insulin dependence is associated with higher risk. Quality measures aimed at limiting complications after LEB may have the most impact if these initiatives are focused on patients who are IDD.

Use of a postoperative insulin protocol decreases wound infection in diabetics undergoing lower extremity bypass.

OBJECTIVE: Strict glucose control in patients undergoing coronary bypass grafting has been shown to decrease infectious complications, arrhythmias, and mortality. Our objective was to determine if strict glucose control reduced morbidity after lower extremity bypass (LEB). METHODS: A prospective pilot study at a single institution within the Vascular Study Group of New England was conducted from January 2009 to December 2010. Patients with diabetes and without undergoing LEB were placed on an intravenous (IV) insulin infusion for 3 days after surgery with titration of blood glucose from 80 to 150 mg/dL. The IV insulin study group (n = 104) was compared to a historic control group (n = 189) that received standard insulin treatment from the preceding 3 years. The Fisher exact test, t-tests, Wilcoxon rank-sum tests, χ(2), and logistic regression analyses were used to compare in-hospital morbidity. Stratified analyses were conducted to determine if findings differed based on the presence or absence of diabetes. RESULTS: There was no difference in postoperative complications between the two groups with regard to graft infection, myocardial infarction, dysrhythmia, primary patency at discharge, or mortality. Patients in the IV insulin group had significantly fewer in-hospital wound infections (4% vs 11%; odds ratio [OR], 0.32; 95% confidence interval [CI], 0.11-0.96; P = .047). This association strengthened after adjusting for potentially confounding baseline differences in gender, body mass index, and smoking status (adjusted OR, 0.22; 95% CI, 0.05-0.84; P = .03). When stratified by presence of diabetes, wound infections were decreased in the IV insulin group (0/44 [0%] vs 9/90 [10%]; P = .03). In patients without diabetes treated with IV insulin, there was no significant difference in wound infections (7% vs 12%; P = .42). CONCLUSIONS: Strict glucose control with a postoperative insulin infusion protocol significantly decreased the incidence of postoperative in-hospital wound infection in the diabetic population. These previously unreported findings from this single-institution prospective study warrant further investigation.

Factors associated with death 1 year after lower extremity bypass in Northern New England.

BACKGROUND: Using 30-day operative mortality reported with lower extremity bypass (LEB) in preoperative decision making may underestimate the actual death rate encountered before patients have truly recovered from surgery, especially in elderly, debilitated patients with significant tissue loss. Therefore, we examined preoperative, patient-level risk factors that predict survival within the first year following LEB. METHODS: Using our regional quality improvement initiative in 11 hospitals in Northern New England, we studied 2306 LEB procedures performed in 2031 patients between January 2003 and December 2007. Sixty surgeons contributed to our database, and over 100 demographic and clinical variables were abstracted by trained researchers. Cox proportional hazards models were used to generate hazard ratios (HR) and surrounding 95% confidence intervals (CI) for our combined outcome measure of death occurring within the first year postoperatively. RESULTS: We found that within our cohort of 2306 bypass procedures, 11% of patients died within 1 year of surgery (2% prior to discharge, 9% prior to 1-year follow-up). We identified six preoperative patient characteristics associated with higher risk of death in multivariate analysis: congestive heart failure (HR 1.3, 95% CI 1.0-1.8), diabetes (HR 1.5, 95% CI 1.1-2.1), critical limb ischemia (CLI) (HR 1.7, 95% CI 1.3-2.4), lack of single-segment saphenous vein (HR 1.9, 95% CI 1.5-2/5), age over 80 (HR 2.0, 95% CI 1.5-2.7), dialysis dependence (HR 2.7, 95% CI 1.9-3.6), and emergent nature of the procedure (HR 3.4, 95% CI 1.7-6.8). While patients with no risk factors had 1-year death rates that were less than 5%: patients with three or more risk factors had a 28% chance of dying before 1 year postoperatively. When we compared risk-adjusted survival across centers, we found that one center in our region performed significantly better than expected (observed-to-expected outcome ratio 0.7, 95% CI 0.6-0.9, P = .04). CONCLUSIONS: Preoperative risk factors allow surgeons to predict survival in the first year following LEB, and to more precisely inform patients about their operative risk with LEB. Additionally, our model facilitates benchmarking comparison of risk-adjusted outcomes across our region. We believe quality improvement measures such as these will allow surgeons to identify best practices and thereby improve outcomes with LEB across centers.

Factors associated with amputation or graft occlusion one year after lower extremity bypass in northern New England.

BACKGROUND: Optimal patient selection for lower extremity bypass surgery requires surgeons to predict which patients will have durable functional outcomes following revascularization. Therefore, we examined risk factors that predict amputation or graft occlusion within the first year following lower extremity bypass. METHODS: Using our regional quality-improvement initiative in 11 hospitals in northern New England, we studied 2,306 lower extremity bypass procedures performed in 2,031 patients between January 2003 and December 2007. Sixty surgeons contributed to our database, and over 100 demographic and clinical variables were abstracted by trained researchers. Cox proportional hazards models were used to generate hazard ratios and surrounding 95% confidence intervals (CIs) for our combined outcome measure of major amputation (above-knee or below-knee) or permanent graft occlusion (loss of secondary patency) occurring within the first year postoperatively. RESULTS: We found that within our cohort of 2,306 bypass procedures 17% resulted in an amputation or graft occlusion within 1 year of surgery. Of the 143 amputations performed (8% of all limbs undergoing bypasses), 17% occurred in the setting of a patent graft. Similarly, of the 277 graft occlusions (12% of all bypasses), 42% resulted in a major amputation. We identified eight preoperative patient characteristics associated with amputation or graft occlusion in multivariate analysis: age <50, nonambulatory status preoperatively, dialysis dependence, diabetes, critical limb ischemia, need for venovenostomy, tarsal target, and living preoperatively in a nursing home. While patients with no risk factors had 1-year amputation/occlusion rates that were <1%, patients with three or more risk factors had a nearly 30% chance of suffering amputation or graft occlusion by 1 year postoperatively. When we compared risk-adjusted rates of amputation/occlusion across centers, we found that one center in our region performed significantly better than expected (observed/expected ratio 0.7, 95% CI 0.6-0.9, p < 0.04). CONCLUSION: Preoperative risk factors allow surgeons to predict the risk of amputation or graft occlusion following lower extremity bypass and to more precisely inform patients about their operative risk and functional outcomes. Additionally, our model facilitates comparison of risk-adjusted outcomes across our region. We believe quality-improvement measures such as these will allow surgeons to identify best practices and thereby improve outcomes across centers.

A regional registry for quality assurance and improvement: the Vascular Study Group of Northern New England (VSGNNE).

OBJECTIVE: A regional cooperative data registry was organized for carotid endarterectomy (CEA), lower extremity bypass (LEB), and infrarenal abdominal aortic aneurysm (AAA) repair (open and endovascular) procedures in Northern New England to allow benchmarking among centers for quality assurance and improvement activities. METHODS: Since January 2003, 48 vascular surgeons from nine hospitals in Maine, New Hampshire, and Vermont (25 to 615 beds) have prospectively recorded patient, procedure, and in-hospital patient outcome data. Results plus 1-year follow-up data analyzed at a central site are reported anonymously to each center at semiannual meetings where care processes and regional benchmarks are discussed. Mortality and compliance with procedure entry were validated by independent comparison with hospital administrative data. Initial improvement efforts focused on optimizing preoperative medication usage. RESULTS: A total of 6143 operations were entered into the registry through December 2006. In-hospital stroke or death after CEA was 1.0%, major amputation or death after LEB was 3.8%, and mortality was 2.9% after elective open and 0.4% after endovascular repair. Variation in results between centers and surgeons provides opportunity for further quality improvement. Any postoperative complication increased median length of stay by > or =3 days. Process improvement efforts initiated in 2004 increased preoperative beta-blocker administration from 72% to 91%, antiplatelet agents from 73% to 83%, and statins from 54% to 72% (all P < .001). Procedure volume and discharge status validation with administrative data led to 99% of appropriate operations being reported to the registry. Mortality was accurately reported to the data registry for all patients. CONCLUSION: This validated regional data registry within a quality improvement initiative has been associated with improved preoperative medication usage. It provides a potential vehicle for future public and pay-for-performance reporting and has the potential to improve patient outcomes. It has been sustained for >4 years and is a model that could be adopted by other regions.

Toward optimal recording of surgical complications: concurrent tracking compared to the discharge data set.

BACKGROUND: Information extracted from the hospital discharge data set is used increasingly for outcomes research and for benchmarking hospital and provider performance. The accuracy of these data in detecting vascular complications has never been validated. METHODS: We compared morbidity and mortality data derived from the hospital discharge data set to similar data recorded concurrently by our Surgical Activity Tracking System (SATS) for 1 year on the vascular surgery service. RESULTS: Of 798 total admissions, no complications were detected by either system in 598 admissions (75%). In 200 admissions (25%), there were 335 complications, including 24 deaths (3.0%), that occurred either in-hospital or within 30 days of the date of operation or the date of discharge for nonoperative admissions. Of the 335 complications, 180 (53.7%) were recorded by both systems; the SATS missed 59 complications recorded in the hospital discharge data set (17.6%), whereas the hospital discharge data set missed 96 complications recorded in the SATS (28.7%, P = .003). Of the 289 in-hospital complications, the SATS recorded 230 (79.5%), whereas the hospital discharge data set recorded 229 (79.2%). Of the 24 deaths, the hospital discharge data set missed 6 that occurred after discharge but within the 30-day reporting period CONCLUSIONS: Both systems are not completely accurate for tracking inpatient complications. The SATS was more representative than the hospital discharge data set in capturing 30-day morbidity and mortality. An amalgamation of the 2 systems would provide more optimal tracking of complications.

Pressure elevation slows the fibroblast response to wound healing.

OBJECTIVE: Chronic venous insufficiency and venous ulceration are consequences of elevated pressure within affected limbs. We hypothesized that wounded cells maintained at different atmospheric pressures heal at different rates and that pressure would adversely affect the processes necessary for wound healing. METHODS: We have developed an in vitro model that replicates venous hypertension in a unique pressurized incubator using neonatal fibroblasts. Neonatal fibroblasts grown to confluence were wounded with a standardized linear incision and then placed in a unique pressure incubator at atmospheric pressure, atmospheric pressure plus 30 mm Hg, atmospheric pressure plus 60 mm Hg, and atmospheric pressure plus 120 mm Hg. Cells were observed daily until complete healing of the wound occurred. Twelve to 18 hours after wounding, proliferating cell nuclear antigen analysis was done by immunocytochemistry. RESULTS: Wounds at atmospheric pressure plus 30 mm Hg were healed by day 3, those at atmospheric pressure plus 60 mm Hg by day 4, and those grown at atmospheric pressure plus 120 mm Hg took > or =4 days for complete healing. Significantly less proliferating cell nuclear antigen activity was present in cells grown at atmospheric pressure plus 60 mm Hg (P < .0001) and atmospheric pressure plus 120 mm Hg (P < .02). Wound edge fluorescence analysis demonstrated less fluorescence in each group compared with atmospheric pressure. CONCLUSIONS: In this model of wound healing under pressure, neonatal fibroblasts grown to confluence and given a standardized wound displayed characteristics consistent with delayed healing. Elevated pressure has a role in the delayed migration and proliferation seen in this model. CLINICAL RELEVANCE: The elevated pressure in patients with venous insufficiency causes their wounds to heal less quickly. Understanding and quantifying the physiology and role of elevated tissue pressure due to venous hypertension will lead to a better understanding of wound healing in these patients.

Pressure-induced cellular senescence: a mechanism linking venous hypertension to venous ulcers.

INTRODUCTION: Slow healing of ulcers in chronic venous insufficiency (CVI) has long been thought secondary to venous hypertension. Dermal fibroblasts isolated from venous ulcers have morphologies and protein production suggestive of premature aging. In this study, we hypothesized that neonatal fibroblasts (NNF) cultured under elevated pressure will demonstrate premature aging and that this effect will be augmented by an inflammatory mediator, transforming growth factor beta (TGF-beta). MATERIALS AND METHODS: A unique pressure incubator was used to culture NNF at atmospheric pressure (ATM), ATM + 30 mmHg, ATM + 60 mmHg, and ATM +120 mmHg. Some pressure-exposed NNF were also cultured with TGF- beta (1 ng/ml). Growth rates were determined by flow cytometry. Senescent cells were identified by staining with a marker for cellular senescence, beta-galactosidase (SA-beta-Gal). Light microscopy and digital imaging were used to evaluate cell morphology. Paired linear models and comparison of the slopes were used for statistical analysis of growth. chi2 analysis was used to compare senescence rates. RESULTS: NNF cultured at ATM + 60 mmHg and ATM + 120 mmHg showed increased SA-beta-Gal activity (P <0.05), and reduced growth rates (P <0.05) at 11 days. These effects were not seen at ATM + 30 mmHg. NNF grown with TGF-beta did not show augmented SA-beta-Gal staining. CONCLUSIONS: Pressure-exposed NNF demonstrated an accelerated aging phenomenon similar to fibroblasts isolated from venous ulcers. This aging effect was directly related to the level of pressure. TGF-beta did not augment the aging effect. This study suggests that pressure elevations result in altered cell function and accelerated aging that may contribute to the slowed healing seen in patients with venous insufficiency.

Evaluating chronic venous disease with a new venous severity scoring system.

BACKGROUND: The Venous Clinical Severity Score (VCSS) has been proposed by the American Venous Forum as an objective means to clinically assess venous disease more completely than with the clinical CEAP classification. However, validation of the VCSS against an objective test is lacking. The purpose of this study was to test the VCSS against abnormalities found on venous ultrasound (US) scans. METHODS: As part of a screening project in a large kindred population with protein C deficiency, VCSS and venous US scanning were performed in 210 patients (420 limbs). A single examiner scored the VCSS (0-3) clinically for pain, varicose veins, edema, skin pigmentation, inflammation, induration, ulcer duration and size, and compressive therapy. Another experienced examiner, blinded to the subject's medical history, performed a US examination of the deep and superficial venous system, with a hand-carried US system. The relationship between US and VCSS scores was analyzed by calculating an odds ratio (OR) and its 95% confidence interval (CI). RESULTS: Of the 420 limbs screened, VCSS was 0 in 283 limbs, and VCSS was 1 or greater in the following categories: pain, 63 limbs; varicose veins, 70 limbs; edema, 51 limbs; skin pigmentation, 17 limbs; inflammation, 2 limbs; induration, 8 limbs; and compressive therapy, 9 limbs. The highest total score in any limb was 8. A clear association was seen with the VCSS and abnormalities found on US scans. When the score was dichotomized (0 = normal, 1 = any abnormality), it was a strong predictor of US scan abnormalities; limbs with VCSS greater than 0 had a 26-fold greater chance of US scan abnormalities than did limbs with VCSS = 0 (OR, 26.5; 95% CI, 11-64). With ultrasonography as the standard, sensitivity of VCSS compared with US scans was 89.3%, and specificity was 76.1%. Negative predictive value of VCSS = 0 was 97.9%, and positive predictive value for any positive score was 36.5% CONCLUSIONS: The results of this study are based on a large kindred population with a higher risk for venous disease than found in the general population. Though the VCSS was devised to quantify the severity of chronic venous disease, this study found it a useful screening tool. The VCSS showed good association with abnormalities on US scans, and when VCSS = 0 there is a high likelihood that the patient does not have venous disease. This simple test may prove valuable in clinical practice.