F. Lee Lucas

Hospital volume, length of stay, and readmission rates in high-risk surgery.

Objective Aimed at reducing surgical deaths, several recent initiatives have attempted to establish volume-based referral strategies in high-risk surgery. Although payers are leading the most visible of these efforts, it is unknown whether volume standards will also reduce resource use. Methods We studied postoperative length of stay and 30-day readmission rate after 14 cardiovascular and cancer procedures using the 1994-1999 national Medicare database (total n = 2.5 million). We used regression techniques to examine the relationship between length of stay, 30-day readmission, and hospital volume, adjusting for age, gender, race, comorbidity score, admission acuity, and mean social security income. Results Mean postoperative length of stay ranged from 3.4 days (carotid endarterectomy) to 19.6 days (esophagectomy). There was no consistent relationship between volume and mean length of stay; it significantly increased across volume strata for 7 of the 14 procedures and significantly decreased across volume strata for the other 7. Mean length of stay at very-low-volume and very-high-volume hospitals differed by more than 1 day for 6 procedures. Of these, the mean length of stay was shorter in high-volume hospitals for 3 procedures (pancreatic resection, esophagectomy, cystectomy), but longer for other procedures (aortic and mitral valve replacement, gastrectomy). The 30-day readmission rate also varied widely by procedure, ranging from 9.9% (nephrectomy) to 22.2% (mitral valve replacement). However, volume was not related to 30-day readmission rate with any procedure. Conclusion Although hospital volume may be an important predictor of operative mortality, it is not associated with resource use as reflected by length of stay or readmission rates.

Hospital-level racial disparities in acute myocardial infarction treatment and outcomes

Background:Previous studies have documented racial disparities in treatment of acute myocardial infarction (AMI) among Medicare beneficiaries. However, the extent to which unobserved differences between hospitals explains some of these differences is unknown. Objective:The objective of this study was to determine whether the observed racial treatment disparities for AMI narrow when analyses account for differences in where blacks and whites are hospitalized. Research Design:Retrospective observational cohort study using Medicare claims and medical record review. Subjects:This study included 130,709 white and 8286 black Medicare patients treated in 4690 hospitals in 50 US states for confirmed AMI in 1994 and 1995. Measures:Measures in this study were receipt of reperfusion, aspirin, and smoking cessation counseling during hospitalization; prescription of aspirin, angiotensin-converting enzyme inhibitor, and beta-blocker at hospital discharge; receipt of cardiac catheterization, percutaneous coronary intervention (PCI), or bypass surgery (CABG) within 30 days of AMI; and 30-day and 1-year mortality. Results:Within-hospital analyses narrowed or erased black–white disparities for medical treatments received during the acute hospitalization, widened black–white disparities for follow-up surgical treatments, and augmented the survival advantage among blacks. These findings indicate that, on average, blacks went to hospitals that had lower rates of evidence-based medical treatments, higher rates of cardiac procedures, and worse risk-adjusted mortality after AMI. Conclusions:Incorporating the hospital effect altered the findings of racial disparity analyses in AMI and explained more of the disparities than race. A policy of targeted hospital-level interventions may be required for success of national efforts to reduce disparities.

Surgeon Volume and Operative Mortality in the United States

Objectives:Although recent studies suggest that physician age is inversely related to clinical performance in primary care, relationships between surgeon age and patient outcomes have not been examined systematically. Methods:Using national Medicare files, we examined operative mortality in approximately 461,000 patients undergoing 1 of 8 procedures between 1998 and 1999. We used multiple logistic regression to assess relationships between surgeon age (≤40 years, 41–50 years, 51–60 years, and >60 years) and operative mortality (in-hospital or within 30 days), adjusting for patient characteristics, surgeon procedure volume, and hospital attributes. Results:Although older surgeons had slightly lower procedure volumes than younger surgeons for some procedures, there were few clinically important differences in patient characteristics by surgeon age. Compared with surgeons aged 41 to 50 years, surgeons over 60 years had higher mortality rates with pancreatectomy (adjusted odds ratio [OR], 1.67; 95% confidence interval [CI], 1.12–2.49), coronary artery bypass grafting (OR, 1.17; 95% CI, 1.05–1.29), and carotid endarterectomy (OR, 1.21; 95% CI, 1.04–1.40). The effect of surgeon age was largely restricted to those surgeons with low procedure volumes and was unrelated to mortality for esophagectomy, cystectomy, lung resection, aortic valve replacement, or aortic aneurysm repair. Less experienced surgeons (≤40 years of age) had comparable mortality rates to surgeons aged 41 to 50 years for all procedures. Conclusions:For some complex procedures, surgeons older than 60 years, particularly those with low procedure volumes, have higher operative mortality rates than their younger counterparts. For most procedures, however, surgeon age is not an important predictor of operative risk.

Survival After Open Versus Endovascular Thoracic Aortic Aneurysm Repair in an Observational Study of the Medicare Population

Background— The goal of this study was to describe short- and long-term survival of patients with descending thoracic aortic aneurysms (TAAs) after open and endovascular repair (TEVAR). Methods and Results— Using Medicare claims from 1998 to 2007, we analyzed patients who underwent repair of intact and ruptured TAA, identified from a combination of procedural and diagnostic International Classification of Disease, ninth revision, codes. Our main outcome measure was mortality, defined as perioperative mortality (death occurring before hospital discharge or within 30 days), and 5-year survival, from life-table analysis. We examined outcomes across repair type (open repair or TEVAR) in crude, adjusted (for age, sex, race, procedure year, and Charlson comorbidity score), and propensity-matched cohorts. Overall, we studied 12 573 Medicare patients who underwent open repair and 2732 patients who underwent TEVAR. Perioperative mortality was lower in patients undergoing TEVAR compared with open repair for both intact (6.1% versus 7.1%; P=0.07) and ruptured (28% versus 46%; P<0.0001) TAA. However, patients with intact TAA selected for TEVAR had significantly worse survival than open patients at 1 year (87% for open, 82% for TEVAR; P=0.001) and 5 years (72% for open; 62% for TEVAR; P=0.001). Furthermore, in adjusted and propensity-matched cohorts, patients selected for TEVAR had worse 5-year survival than patients selected for open repair. Conclusions— Although perioperative mortality is lower with TEVAR, Medicare patients selected for TEVAR have worse long-term survival than patients selected for open repair. The results of this observational study suggest that higher-risk patients are being offered TEVAR and that some do not benefit on the basis of long-term survival. Future work is needed to identify TEVAR candidates unlikely to benefit from repair.

Ischemic preconditioning at a remote site prevents acute kidney injury in patients following cardiac surgery

Acute kidney injury, a common complication of cardiac surgery with cardiopulmonary bypass, is associated with increased morbidity and mortality. Ischemic preconditioning at a remote site mitigates ischemia-reperfusion injury and may prevent acute kidney injury after cardiac surgery, thus providing clinical benefit. To further study this, we enrolled 120 adult patients undergoing elective cardiac surgery for whom cardiopulmonary bypass was anticipated in a randomized, single-blind, and controlled pilot trial. Patients were stratified for the type of surgery and equally assigned to a control group or to receive remote ischemic preconditioning by an automated thigh tourniquet consisting of three 5-min intervals of lower extremity ischemia separated by 5-min intervals of reperfusion. The primary end point was acute kidney injury defined as an elevation of serum creatinine of ≥0.3 mg/dl or ≥50% within 48 h after surgery. Fifty-nine patients in each group were analyzed on an intention-to-treat basis. Acute kidney injury occurred in 12 remote ischemic preconditioned and 28 control patients, reflecting an absolute risk reduction of 0.27 and a significantly reduced relative risk due to preconditioning of 0.43. Hence, remote ischemic preconditioning prevents acute kidney injury in patients undergoing cardiopulmonary bypass-assisted cardiac surgery.

Outcomes Following Coronary Stenting in the Era of Bare-Metal vs the Era of Drug-Eluting Stents

CONTEXT Although drug-eluting stents reduce restenosis rates relative to bare-metal stents, concerns have been raised that drug-eluting stents may also be associated with an increased risk of stent thrombosis. Our study focused on the effect of stent type on population-based interventional outcomes. OBJECTIVE To compare outcomes of Medicare beneficiaries who underwent nonemergent coronary stenting before and after the availability of drug-eluting stents. DESIGN, SETTING, AND PATIENTS Observational study of 38,917 Medicare patients who underwent nonemergent coronary stenting from October 2002 through March 2003 when only bare-metal stents were available (bare-metal stent era cohort) and 28,086 similar patients who underwent coronary stenting from September through December 2003, when 61.5% of patients received a drug-eluting stent and 38.5% received a bare-metal stent (drug-eluting stent era cohort). Follow-up data were available through December 31, 2005. MAIN OUTCOME MEASURES Coronary revascularization (percutaneous coronary intervention, coronary artery bypass surgery), ST-elevation myocardial infarction, survival through 2 years of follow-up. RESULTS Relative to the bare-metal stent era, patients treated in the drug-eluting stent era had lower 2-year risks for repeat percutaneous coronary interventions (17.1% vs 20.0%, P < .001) and coronary artery bypass surgery (2.7% vs 4.2%, P < .01). The difference in need for repeat revascularization procedures between these 2 eras remained significant after risk adjustment (hazard ratio, 0.82; 95% confidence interval, 0.79-0.85). There was no difference in unadjusted mortality risks at 2 years (8.4% vs 8.4%, P =.98 ), but a small decrease in ST-elevation myocardial infarction existed (2.4% vs 2.0%, P < .001). The adjusted hazard of death or ST-elevation myocardial infarction at 2 years was similar (hazard ratio, 0.96; 95% confidence interval, 0.92-1.01). CONCLUSION The widespread adoption of drug-eluting stents into routine practice was associated with a decline in the need for repeat revascularization procedures and had similar 2-year risks for death or ST-elevation myocardial infarction to bare-metal stents.

Variation in the Use of Lower Extremity Vascular Procedures for Critical Limb Ischemia

Background— Many believe that variation in vascular practice may affect limb salvage rates in patients with severe peripheral arterial disease. However, the extent of variation in procedural vascular care obtained by patients with critical limb ischemia (CLI) remains unknown. Methods and Results— By using Medicare 2003 to 2006 data, we identified all patients with CLI who underwent major lower extremity amputation in the 306 hospital referral regions described in the Dartmouth Atlas of Healthcare. For each patient, we studied the use of lower extremity vascular procedures (open surgery or endovascular intervention) in the year before amputation. Our main outcome measure was the intensity of vascular care, defined as the proportion of patients in the hospital referral region undergoing a vascular procedure in the year before amputation. Overall, 20 464 patients with CLI underwent major lower extremity amputations during the study period, and collectively underwent 25 800 vascular procedures in the year before undergoing amputation. However, these procedures were not distributed evenly: 54% of patients had no vascular procedures performed in the year before amputation, 14% underwent 1 vascular procedure, and 32% underwent >1 vascular procedure. In the regions in the lowest quintile of vascular intensity, vascular procedures were performed in 32% of patients. Conversely, in the regions in the highest quintile of vascular intensity, revascularization was performed in 58% of patients in the year before amputation (P<0.0001). In analyses accounting for differences in age, sex, race, and comorbidities, patients in high-intensity regions were 2.4 times as likely to undergo revascularization in the year before amputation than patients in low-intensity regions (adjusted odds ratio, 2.4; 95% CI, 2.1–2.6; P<0.001). Conclusions— Significant variation exists in the intensity of vascular care provided to patients in the year before major amputation. In some regions, patients receive intensive care, whereas in other regions, far less vascular care is provided. Future work is needed to determine the association between intensity of vascular care and limb salvage.

National trends and regional variation of open and endovascular repair of thoracic and thoracoabdominal aneurysms in contemporary practice

OBJECTIVES Successful surgical management of thoracic aortic aneurysms (TAA) and thoracoabdominal aortic aneurysms (TAAA) has historically relied upon open surgical repair (OSR). More recently, the advent and application of thoracic endovascular stent graft aneurysm repair (TEVAR) permutations have become increasingly performed in contemporary practice. To better determine the effect of TEVAR techniques on OSR, we examined national and regional trends in treatment use. METHODS All Medicare patients from 1998 through 2007 undergoing isolated TAA and TAAA repair were analyzed using a clinically validated algorithm using diagnostic International Classification of Disease 9th revision (ICD-9; 441.1, 441.2, 441.6, 441.7, 441.9) codes and procedural (ICD-9 OSR: 38.35, 38.45 and TEVAR: 39.73, 39.79) codes. Differential rates of OSR and TEVAR were compared across census tract regions during the study interval. RESULTS Total complex aortic repairs increased by 60%, from 10.8 to 17.8/100,000, between 1998 and 2007 (P < .001). A dramatic increase occurred in TEVAR (not performed in 1998, 5.8/100,000 in 2007) during the study period, but OSR rates remained stable during the same interval (10.7 to 12.0/100,000 in 2007, P = NS). There was substantial regional variation for both OSR and TEVAR. This regional variation was greater in OSR (range, 8.8-16.7/100,000) than in TEVAR (range, 4.5-6.9/100,000). CONCLUSIONS Degenerative TAA and TAAA aneurysms are being repaired in the United States at an increasing rate. This reflects the rapid acceptance of TEVAR, which apparently supplements rather than supplants OSR. There appears to be greater regional variation in OSR compared with TEVAR. These data may have significant implications for those interested in the effect of new technologies on health care and cost containment.

Is surgery getting safer? National trends in operative mortality.

BACKGROUND Although mortality rates for some cardiovascular procedures seem to have declined, it is unclear whether other high-risk procedures are becoming safer over time. STUDY DESIGN We examined national trends between 1994 and 1999 in operative mortality for 14 high-risk cardiovascular and cancer procedures in the national population of Medicare beneficiaries over age 65. Secular trends were examined using logistic regression adjusting for age, gender, race, socioeconomic status, admission acuity, comorbidities, and hospital volume. RESULTS Observed mortality rates varied widely across the 14 procedures, from 2% (carotid endarterectomy) to 16% (esophagectomy). Over the 6-year study period, average patient age increased for all procedures, and patients were more likely to undergo operation at high-volume hospitals for some procedures (pancreatic resection, esophagectomy, cystectomy, and pneumonectomy). After accounting for these changes, operative mortality declined significantly for three cardiovascular procedures, as evidenced by adjusted odds ratios (OR) for the 6-year effect on operative mortality (coronary artery bypass graft OR = 0.85, 95% confidence interval [CI] 0.81 to 0.88; carotid endarterectomy OR = 0.86,95% CI 0.80 to 0.93; mitral valve replacement OR = 0.89, 95% CI 0.81 to 0.97). In contrast, operative mortality did not decline for any of the cancer procedures. In fact, adjusted mortality increased for colectomy for colon cancer (OR= 1.13, 95% CI 1.07 to 1.19). CONCLUSIONS Although risks of some cardiovascular procedures are declining over time, there is no evidence that other types of high-risk surgery are becoming safer. These findings suggest the need for systematic efforts to monitor and improve surgical performance.

Regional Variation in Carotid Artery Stenting and Endarterectomy in the Medicare Population

Background—To describe geographic variation in population-based rates of carotid artery stenting (CAS) and carotid endarterectomy (CEA) performed in Medicare beneficiaries. Methods and Results—Medicare claims and enrollment data were used to calculate age, sex, and race-adjusted rates of CAS and CEA for Medicare beneficiaries in each of 306 hospital referral regions between 1998 and 2007. Procedures were identified using a combination of Current Procedural Terminology codes as well as diagnostic and procedural ICD-9 codes. Overall, the rate of carotid revascularization has fallen slightly over the last decade (3.8 procedures per 1000 in 1998, 3.1 procedures per 1000 in 2007; P<0.0001). Although the use of CEA decreased, from 3.6 to 2.5 procedures per 1000 beneficiaries in 2007 (P<0.0001), the use of CAS has increased >4-fold between 1998 and 2007, growing from 0.1 to 0.6 CAS procedures per 1000 beneficiaries (P<0.0001). Further, CAS rapidly disseminated across the country over the last decade. In 1998, 66% of hospital referral regions had a hospital that performed CAS; however, by 2007, nearly all (95%) hospital referral regions performed CAS (P<0.0001). Last, in regions with the highest utilization rates of CAS, it appeared that CAS was performed as a substitute for CEA. There was little evidence that CAS was being performed in addition to CEA, as no correlation existed between regional rates of CAS and CEA (r=0.06). Conclusions—Even though CEA was used less frequently in 2007 than 1998, the use of CAS has grown significantly. Although regional variation in the use of CEA has remained fairly constant, regional variation has increased in the use of CAS. Given these changes in practice patterns, careful examination of the efficacy and cost-effectiveness of CAS is necessary.