Chuntao Wu

Drug-Eluting Stents vs. Coronary-Artery Bypass Grafting in Multivessel Coronary Disease

BACKGROUND Numerous studies have compared the outcomes of two competing interventions for multivessel coronary artery disease: coronary-artery bypass grafting (CABG) and coronary stenting. However, little information has become available since the introduction of drug-eluting stents. METHODS We identified patients with multivessel disease who received drug-eluting stents or underwent CABG in New York State between October 1, 2003, and December 31, 2004, and we compared adverse outcomes (death, death or myocardial infarction, or repeat revascularization) through December 31, 2005, after adjustment for differences in baseline risk factors among the patients. RESULTS In comparison with treatment with a drug-eluting stent, CABG was associated with lower 18-month rates of death and of death or myocardial infarction both for patients with three-vessel disease and for patients with two-vessel disease. Among patients with three-vessel disease who underwent CABG, as compared with those who received a stent, the adjusted hazard ratio for death was 0.80 (95% confidence interval [CI], 0.65 to 0.97) and the adjusted survival rate was 94.0% versus 92.7% (P=0.03); the adjusted hazard ratio for death or myocardial infarction was 0.75 (95% CI, 0.63 to 0.89) and the adjusted rate of survival free from myocardial infarction was 92.1% versus 89.7% (P<0.001). Among patients with two-vessel disease who underwent CABG, as compared with those who received a stent, the adjusted hazard ratio for death was 0.71 (95% CI, 0.57 to 0.89) and the adjusted survival rate was 96.0% versus 94.6% (P=0.003); the adjusted hazard ratio for death or myocardial infarction was 0.71 (95% CI, 0.59 to 0.87) and the adjusted rate of survival free from myocardial infarction was 94.5% versus 92.5% (P<0.001). Patients undergoing CABG also had lower rates of repeat revascularization. CONCLUSIONS For patients with multivessel disease, CABG continues to be associated with lower mortality rates than does treatment with drug-eluting stents and is also associated with lower rates of death or myocardial infarction and repeat revascularization.

Off-pump versus on-pump coronary artery bypass graft surgery: differences in short-term outcomes and in long-term mortality and need for subsequent revascularization.

Background— Off-pump coronary artery bypass graft surgery (OPCAB) has been performed for many years, but its use is increasing in frequency, and it remains an open question whether OPCAB is associated with better outcomes than on-pump coronary artery bypass graft (CABG) surgery. Methods and Results— New York State patients who underwent either OPCAB with median sternotomy (13 889 patients) or on-pump CABG surgery (35 941 patients) between 2001 and 2004 were followed up via New York databases. Short- and long-term outcomes were compared after adjustment for patient risk factors and after patients were matched on the basis of significant predictors of type of CABG surgery. OPCAB had a significantly lower inpatient/30-day mortality rate (adjusted OR 0.81, 95% confidence interval [CI] 0.68 to 0.97), lower rates for 2 perioperative complications (stroke: adjusted OR 0.70, 95% CI 0.57 to 0.86; respiratory failure: adjusted OR 0.80, 95% CI 0.68 to 0.93), and a higher rate of unplanned operation in the same admission (adjusted OR 1.47, 95% CI 1.01 to 2.15). In the matched samples, no difference existed in 3-year mortality (hazard ratio 1.08, 95% CI 0.96 to 1.22), but OPCAB patients had higher rates of subsequent revascularization (hazard ratio 1.55, 95% CI 1.33 to 1.80). The 3-year OPCAB and on-pump survival rates for matched patients were 89.4% and 90.1%, respectively (P=0.20). For freedom from subsequent revascularization, the respective rates were 89.9% and 93.6% (P<0.0001). Conclusions— OPCAB is associated with lower in-hospital mortality and complication rates than on-pump CABG, but long-term outcomes are comparable, except for freedom from revascularization, which favors on-pump CABG.

Do Hospitals and Surgeons With Higher Coronary Artery Bypass Graft Surgery Volumes Still Have Lower Risk-Adjusted Mortality Rates?

Background—Studies that are the basis of recommended volume thresholds for CABG surgery are outdated and not reflective of recent advances in the field. This study examines both hospital and surgeon volume-mortality relations for CABG surgery through the use of a population-based clinical data set. Methods and Results—Data from New York’s clinical CABG surgery registry from 1997 to 1999 (total number of procedures, 57 150) were used to examine the individual and combined impact of annual hospital volume and annual surgeon volume on in-hospital mortality rates after adjusting for differences in severity of illness. Significantly lower risk-adjusted mortality rates occurred above all annual hospital volume thresholds between 200 and 800 and above all surgeon volume thresholds between 50 and 200. The number needed to treat (NNT) at higher-volume providers to avoid a death was minimized for a hospital threshold volume of 100 (NNT=50) and a surgeon threshold volume of 50 (NNT=118). The risk-adjusted mortality rate (RAMR) for patients undergoing surgery performed by surgeons with volumes of ≥125 in hospitals with volumes of ≥600 was 1.89%. The RAMR was significantly higher (2.67%) for patients undergoing surgery performed by surgeons with volumes of <125 in hospitals with volumes of <600. Conclusions—Higher-volume surgeons and hospitals continue to have lower risk-adjusted mortality rates, and patients undergoing surgery performed by higher-volume surgeons in higher-volume hospitals have the lowest mortality rates.

Volume-outcome relationships for percutaneous coronary interventions in the stent era.

Background—Most studies that are the basis of recommended volume thresholds for percutaneous coronary interventions (PCIs) predate the routine use of stent placement. Methods and Results—Data from New York’s Percutaneous Coronary Interventions Reporting System in 1998 to 2000 (n=107 713) were used to examine the impact of annual hospital volume and annual operator volume on in-hospital mortality, same-day coronary artery bypass graft (CABG) surgery, and same- stay CABG surgery after adjustment for differences in patients’ severity of illness. For a hospital-volume threshold of 400, the odds ratios for low-volume hospitals versus high-volume hospitals were 1.98 (95% CI, 1.17, 3.35) for in-hospital mortality, 2.07 (95% CI, 1.36, 3.15) for same-day CABG surgery, and 1.51 (95% CI, 1.03, 2.21) for same-stay CABG surgery. For an operator-volume threshold of 75, the odds ratios for low-volume versus high-volume operators were 1.65 (95% CI, 1.05, 2.60) for same-day CABG surgery and 1.55 (95% CI, 1.10, 2.18) for same-stay CABG surgery. Operator volume was not significantly associated with mortality. Also, for hospital volumes below 400 and operator volumes below 75, the respective odds of mortality, same-day CABG surgery, and same-stay CABG surgery were 5.92, 4.02, and 3.92 times the odds for hospital volumes of 400 or higher and operator volumes of 75 or higher. Conclusions—Higher-volume operators and hospitals continue to experience lower risk-adjusted PCI outcome rates.

Incomplete Revascularization in the Era of Drug-Eluting Stents: Impact on Adverse Outcomes

OBJECTIVES We sought to compare outcomes for percutaneous coronary intervention patients undergoing complete revascularization (CR) and incomplete revascularization (IR) in the drug-eluting stent era. BACKGROUND There have been relatively few studies that have examined the impact of IR in patients undergoing coronary stenting, particularly in the era of drug-eluting stents. METHODS New York States Percutaneous Coronary Intervention Reporting System was used to identify 11,294 stent patients with multivessel disease undergoing either IR or CR in 39 hospitals between October 1, 2003, and December 31, 2004. These patients were followed through December 31, 2005, and IR patients were subdivided based on the number of IR vessels and presence of a chronic total occlusion. Risk-adjusted mortality and mortality/myocardial infarction (MI) for CR and IR patients were compared at 18 months. RESULTS Incomplete revascularization was performed in a total of 7,795 patients (69.0%). Incomplete revascularization was associated with higher 18-month mortality (adjusted hazard ratio [HR]: 1.23, 95% confidence interval [CI]: 1.04 to 1.45) and higher 18-month MI/mortality (adjusted HR: 1.27, 95% CI: 1.09 to 1.47). The risk-adjusted survival rates for CR and IR were 94.9% and 93.8% (p = 0.01). The risk-adjusted survival/freedom from MI rates were 93.3% and 91.7% (p = 0.002). Patients with 2 diseased vessels unattempted with a total occlusion were at highest risk (adjusted survival HR: 1.44, 95% CI: 1.14 to 1.82, risk-adjusted survival 94.9% vs. 92.9%, p = 0.002; and adjusted survival/freedom from MI: 1.50, 95% CI: 1.21 to 1.86, rates 93.3% vs. 90.3%, p < 0.001). CONCLUSIONS Patients undergoing coronary stenting who receive IR experience more adverse outcomes even in the era of drug-eluting stents. This has implications for choice of procedure and post-procedural monitoring.

Is the Impact of Hospital and Surgeon Volumes on the In-Hospital Mortality Rate for Coronary Artery Bypass Graft Surgery Limited to Patients at High Risk?

Background—Restriction of volume-based referral for CABG surgery to high-risk patients has been suggested, and earlier studies have reached different conclusions regarding volume-based referral for low-risk patients. Methods and Results—Patients who underwent isolated CABG surgery in New York from 1997 through 1999 (n=57 150) were separated into low-risk and moderate-to-high-risk groups with a predicted probability of in-hospital death of 2% as the cutoff point. The provider volume-mortality relationship was examined for both groups. For annual hospital volume thresholds between 200 and 600 cases, the adjusted ORs of in-hospital mortality for high-volume to low-volume hospitals ranged from 0.45 to 0.77 and were all significant for the low-risk group; for the moderate-to-high-risk group, ORs ranged from 0.62 to 0.91, and most were significant. The number needed to treat at higher-volume hospitals to avoid 1 death was greater for the low-risk group (a range of 114 to 446 versus 37 to 184). As the annual surgeon volume threshold increased from 50 to 150 cases, the ORs for high- to low-volume surgeons increased from 0.43 to 0.74 for the low-risk group; for the moderate-to-high-risk group, ORs ranged from 0.79 to 0.86. Compared with patients treated by surgeons with volumes of <125 in hospitals with volumes of <600, patients treated by higher-volume surgeons in higher-volume hospitals had a significantly lower risk of death; in particular, the OR was 0.52 for the low-risk group. Conclusions—For both low-risk and moderate-to-high-risk patients, higher provider volume is associated with lower risk of death.

Predicting Risk-adjusted Mortality for Cabg Surgery: Logistic Versus Hierarchical Logistic Models

Background:In recent years, several studies in the medical and health service research literature have advocated the use of hierarchical statistical models (multilevel models or random-effects models) to analyze data that are nested (eg, patients nested within hospitals). However, these models are computer-intensive and complicated to perform. There is virtually nothing in the literature that compares the results of standard logistic regression to those of hierarchical logistic models in predicting future provider performance. Objective:We sought to compare the ability of standard logistic regression relative to hierarchical modeling in predicting risk-adjusted hospital mortality rates for coronary artery bypass graft (CABG) surgery in New York State. Design, Setting and Patients:New York State CABG Registry data from 1994 to 1999 were used to relate statistical predictions from a given year to hospital performance 2 years hence. Main Outcome Measures:Predicted and observed hospital mortality rates 2 years hence were compared using root mean square errors, the mean absolute difference, and the number of hospitals whose predicted mortality rate data was within a 95% confidence interval around the observed mortality rate. Results:In these data, standard logistic regression performed similarly to hierarchical models, both with and without a second level covariate Differences in the criteria used for comparison were minimal, and when the differences could be statistically tested no significant differences were identified. Conclusions:It is instructive to compare the predictive abilities of alternative statistical models in the process of assessing their relative performance on a specific database and application.

Utilization and Outcomes of Unprotected Left Main Coronary Artery Stenting and Coronary Artery Bypass Graft Surgery

BACKGROUND Limited contemporary information is available on outcomes for patients with unprotected left main coronary artery (LMCA) disease who are revascularized. METHODS We examined the relative frequency, severity of illness, and outcomes of stenting and coronary artery bypass graft (CABG) surgery for treating unprotected LMCA disease in New York between January 1, 2000 and December 31, 2004. A total of 16,336 (98.7%) patients who underwent CABG surgery and 212 (1.3%) who underwent stenting were included in this study. RESULTS Stent patients had higher preprocedural severity of illness (eg, they were older, more likely to be female, and had more comorbidities). A total of 135 stent patients were matched to 135 CABG patients on baseline characteristics identified by a propensity model as predictors of type of procedure received. At the end of follow-up on December 31, 2004, the respective 2-year survival rates were 94.1% and 82.0% (hazard ratio = 0.32, p = 0.005) for the 135 pairs of matched CABG and stent patients. The respective 2-year rates for freedom from subsequent revascularization were 93.7% and 62.7% (hazard ratio = 0.15, p < 0.001). In the drug-eluting stent era between October 1, 2003 and December 31, 2004, the same trends in mortality (hazard ratio = 0.73, p = 0.69) and repeat revascularization (hazard ratio = 0.10, p = 0.03) were observed among the 56 pairs of matched CABG and drug-eluting stent patients. CONCLUSIONS Most patients with LMCA disease who needed coronary revascularization received CABG surgery; stent patients were sicker. This study found that surgery patients experienced lower risk of long-term death and repeat revascularization. However, more studies comparing these procedures are needed, especially in the drug-eluting stent era.

Impact of Incomplete Revascularization on Long-Term Mortality After Coronary Stenting

Background— The impact of incomplete revascularization (IR) on adverse outcomes after percutaneous coronary intervention remains inconclusive, and few studies have examined mortality during follow-ups longer than 5 years. The objective of this study is to test the hypothesis that IR is associated with higher risk of long-term (8-year) mortality after stenting for multivessel coronary disease. Methods and Results— A total of 13 016 patients with multivessel disease who had undergone stenting procedures with bare metal stents in 1999 to 2000 were identified in the New York States Percutaneous Coronary Intervention Reporting System. A logistic regression model was fit to predict the probability of achieving complete revascularization (CR) in these patients using baseline risk factors; then, the CR patients were matched to the IR patients with similar likelihoods of achieving CR. Each patients vital status was followed through 2007 using the National Death Index, and the difference in long-term mortality between IR and CR was compared. It was found that CR was achieved in 29.2% (3803) of the patients. For the 3803 pair-matched patients, the respective 8-year survival rates were 80.8% and 78.5% for CR and IR (P=0.04), respectively. The risk of death was marginally significantly higher for IR (hazard ratio=1.12; 95% confidence interval, 1.01–1.26, P=0.04). The 95% bootstrap confidence interval for the hazard ratio was 0.98 to 1.32. Conclusions— IR may be associated with higher risk of long-term mortality after stenting with BMS in patients with multivessel disease. More prospective studies are needed to further test this association.

Long-term mortality of coronary artery bypass graft surgery and stenting with drug-eluting stents.

BACKGROUND Few studies have examined differences in long-term mortality between coronary artery bypass graft surgery and stenting with drug-eluting stents (DES) for multivessel disease without left main coronary artery stenosis. This study compares the risks of long-term mortality between these 2 procedures during a follow-up of up to 5 years. METHODS Patients who underwent isolated bypass surgery (n=13,212) and stenting with DES (n=20,161) between October 2003 and December 2005 in New York State were followed for their vital status through 2008. To control for treatment selection bias, bypass and stenting patients were matched on age, number of diseased coronary vessels, presence of proximal or nonproximal left anterior descending (LAD) artery disease, and propensity of undergoing bypass surgery. Five-year survival rates for the 2 procedures were compared and hazard ratios for death of bypass surgery compared with stenting were obtained. RESULTS The respective 5-year survival rates in the 8,121 pairs of matched bypass and stenting patients were 80.4% and 73.6% (p<0.001), and the risk of death after bypass surgery was 29% lower than for stenting (hazard ratio = 0.71, 95% confidence interval: 0.67 to 0.77, p<0.001). Significantly lower risks of death for bypass surgery were observed in patients with LAD artery disease but not in patients without LAD artery disease. Significantly lower risks of death for bypass surgery were also found in all patient subgroups defined by the presence of selected baseline risk factors. CONCLUSIONS Bypass surgery is associated with lower risk of death than stenting with DES for multivessel disease without left main stenosis.