The Midterm Impact of Transcatheter Aortic Valve Replacement on Surgical Aortic Valve Replacement in Michigan.

BACKGROUND: We characterized the midterm impact of transcatheter aortic valve replacement (TAVR) on surgical aortic valve replacement (SAVR) volume, patient profiles, and outcomes in Michigan. METHODS: We analyzed data obtained after SAVR (n = 15,288) and TAVR (n = 1,783) using the Michigan Society of Thoracic and Cardiovascular Surgery Quality Collaborative from 2006 to 2015. During this period, 17 of 33 hospitals developed TAVR programs. RESULTS: Annual SAVR volume increased by 38.1% at TAVR hospitals and by 20.4% at non-TAVR hospitals, (p trend < 0.001). In TAVR hospitals, the Society of Thoracic Surgeons (STS) Predicted Risk of Mortality (PROM) decreased before (4.7% ± 5.1%) and after (3.5% ± 3.6%) initiation of TAVR (p < 0.001). Rates of 30-day mortality (pre-TAVR, 3.9% vs post-TAVR, 2.7%; p < 0.001) and renal failure (pre-TAVR, 5.2% vs post-TAVR, 3.3%; p < 0.001) but not stroke (pre-TAVR, 1.9% vs post-TAVR, 1.7%; p = 0.47) were lower after TAVR implementation. Length of stay decreased from 9.0 to 8.5 days (p < 0.001). When analyzing high-risk patients undergoing SAVR (ie, PROM >8%), neither mortality, stroke, nor renal failure was different (all p > 0.15). Despite a reduction in the STS-PROM, non-TAVR hospitals did not display changes in mortality, stroke, or renal failure for either the entire or the high-risk SAVR cohorts after initiation of TAVR in Michigan. CONCLUSIONS: TAVR implementation in Michigan has dramatically increased overall SAVR volume. This phenomenon has occurred with a concomitant decrease in preoperative risk profile and has improved early SAVR outcomes, particularly at TAVR hospitals, but surprisingly not in patients considered at high preoperative risk. As TAVR use increases, these issues may be further clarified and elucidated.

Red blood cells and mortality after coronary artery bypass graft surgery: an analysis of 672 operative deaths.

BACKGROUND: Prior studies have implicated transfusion as a risk factor for mortality in coronary artery bypass graft surgery (CABG). To further our understanding of the true association between transfusion and outcome, we specifically analyzed the subgroup of patients who died after undergoing CABG. METHODS: A total of 34,362 patients underwent isolated CABG between January 2008 and September 2013 and were entered into a statewide collaborative database; 672 patients (2.0%) died and form the basis for this study. Univariate analysis compared preoperative and intraoperative variables, as well as postoperative outcomes, between those with and without transfusion in both unadjusted cohorts and those matched by predicted risk of mortality (PROM). Mortality was further evaluated with phase of care analysis. RESULTS: Of the 672 deaths, 566 patients (84.2%) received a transfusion of red blood cells. The PROM was 7.5% for the transfused patients versus 4.3% for those not transfused (p < 0.001). Transfused patients were older, more often female, had more emergency, on-pump, and redo procedures, and had a lower preoperative and on-bypass nadir hematocrit. Most other demographics were similar between the groups. Postoperatively, transfused patients were ventilated longer, had more renal and multisystem organ failure, and were more likely to die of infectious and pulmonary causes after longer intensive care unit and overall lengths of stay. CONCLUSIONS: Significant differences in PROM and the postoperative course leading to death between those with and without transfusion suggest the role of transfusion may be secondary to other patient-related factors. Recognizing that the relationship between transfusion and outcome after CABG remains incompletely understood, these findings are suggestive of a complex interaction of many variables.

Transfusion of 1 and 2 units of red blood cells is associated with increased morbidity and mortality.

BACKGROUND: This study examined the relationship between transfusion of 1 or 2 units of red blood cells (RBCs) and the risk of morbidity and mortality after isolated on-pump coronary artery bypass grafting (CABG). METHODS: A total of 22,785 consecutive patients underwent isolated on-pump CABG between January 1, 2008, and December 31, 2011 in Michigan. We excluded 5,950 patients who received three or more RBC units. Twenty-one preoperative variables significantly associated with transfusion by univariate analysis were included in a logistic regression model predicting transfusion, and propensity scores were calculated. Transfusion and the propensity score covariate were included in additional logistic regression models predicting mortality and each of 11 postoperative outcomes. RESULTS: Operative mortality for the study cohort of 16,835 patients was 0.8% overall, 0.5% for the 10,884 patients with no transfusion, and 1.3% for the 5,951 patients who received transfusion of 1 or 2 units (odds ratio 2.44; confidence interval 1.74 to 3.42; p < 0.0001). The association between transfusion and mortality lessened after propensity adjustment but remained highly significant (odds ratio 1.86; confidence interval 1.21 to 2.87; p = 0.005). Of the 11 postoperative outcomes studied, all but sternal wound infection and need for dialysis were also significantly associated with transfusion. CONCLUSIONS: Transfusion of as little as 1 or 2 units of RBCs is common and is significantly associated with increased morbidity and mortality after on-pump CABG. The relationship persists after adjustment for preoperative risk factors. These results suggest that aggressive attempts at blood conservation and avoidance of even small amounts of RBC transfusion may improve outcomes after CABG.

Morbidity but not mortality is decreased after off-pump coronary artery bypass surgery.

BACKGROUND: Off-pump coronary bypass surgery (CABG) has been advocated to avoid the physiologic perturbations related to cardiopulmonary bypass and improve outcomes compared with on-pump CABG. Previous reports have been inconsistent, and thus its benefits remain uncertain. This retrospective study compared outcomes between on-pump and off-pump CABG from a large multicenter cohort of propensity-matched patients. METHODS: The study consisted of 21,640 patients (19,639 [90.8%] on-pump, 2,001 [9.2%] off-pump) who underwent isolated CABG between January 1, 2008, and June 30, 2011, and were entered into a statewide collaborative database. Univariate analysis compared 37 baseline characteristics between on-pump and off-pump procedures. Patients were matched 1:1 based on similarities in propensity scores derived from statistically significant baseline characteristics. Propensity scores and surgery type were used in conditional logistic regression models for predicting each of 14 postoperative outcomes using the sample of 3,898 matched procedures. RESULTS: Patients undergoing off-pump CABG had significantly fewer complications overall, including decreased red blood cell transfusion, stroke, intensive care unit and ventilator time, reoperation for bleeding, and length of stay. There was no difference in renal failure, wound infection, discharge location, or 30-day readmission rate. Although off-pump patients received fewer bypass grafts per patient (2.5 ± 1.2 versus 3.0 ± 1.1; p < 0.001), operative mortality was similar for the two groups (1.8% on-pump versus 2.3% off-pump; p = 0.30). CONCLUSIONS: Off-pump CABG was associated with less morbidity, shorter length of stay, and similar mortality compared with on-pump procedures, suggesting that it can be a safe and effective alternative to standard on-pump CABG. However, the limited use of off-pump CABG in this multicenter analysis may restrict the generalizability of these results, and realistically defines the limited degree of acceptance of this technique in a real-world environment.

Aortic valve replacement: using a statewide cardiac surgical database identifies a procedural volume hinge point.

BACKGROUND: Expanding therapies for aortic stenosis have focused on high-risk and inoperable patients, suggesting that an evaluation of outcomes of conventional aortic valve replacement (AVR) or AVR and coronary artery bypass grafting (CABG) is timely and warranted. METHODS: Outcomes for 6,270 AVR (3,487) or AVR/CABG (2,783) procedures performed in Michigan (2008-2011) were analyzed using a statewide cardiothoracic surgical database. Hospital and surgeon volume-outcome relationships were assessed. RESULTS: Independent predictors of early mortality (all p < 0.05) included age, female sex, predicted risk of mortality, and hospital volume, with a hinge point of a 4-year volume of 390 procedures (high-volume hospital [HVH], 2.41% versus low-volume hospital [LVH], 4.34%; p < 0.001). At this hinge point, observed to expected ratio (O/E) for operative mortality after AVR was lower in HVHs for patients with a predicted risk of mortality (PRoM) greater than 4.7%. In contrast, no surgeon-volume outcome relationship was identified, even when stratified by preoperative patient-risk profile. With respect to other measures, HVHs reported lower rates of prolonged ventilation (24.9% versus LVH, 30.9%; p < 0.001), postoperative transfusion (46.1% versus LVH, 59.0%; p < 0.001), pneumonia (6.6% versus LVH, 9.0%; p = 0.01), and multisystem organ failure (0.7% versus LVH, 1.8%; p = 0.012). CONCLUSIONS: This population-based analysis suggests that volume-outcome relationships exist for AVR. The predominant effect on mortality appears based on the setting of the procedure and occurs primarily in the high-risk patient. These results provide an opportunity to review approaches for high-risk patients undergoing AVR, including resource availability and system experience as the spectrum of treatment options expands to transcatheter therapies.

Transfusion rate as a quality metric: is blood conservation a learnable skill?

BACKGROUND: Between January 2008 and December 2012, a multicenter quality collaborative initiated a focus on blood conservation as a quality metric, with educational presentations and quarterly reporting of institutional-level perioperative transfusion rates and outcomes. This prospective cohort study was undertaken to determine the effect of that initiative on transfusion rates after isolated coronary artery bypass grafting (CABG). METHODS: Between January 1, 2008, and December 31, 2012, 30,271 patients underwent isolated CABG in Michigan. Evaluated were annual crude and adjusted trends in overall transfusion rates for red blood cells (RBCs), fresh frozen plasma (FFP), and platelets, and in operative death. RESULTS: Transfusion rates continuously decreased for all blood products. RBC use decreased from 56.4% in 2008 (baseline) to 38.3% in 2012, FFP use decreased from 14.8% to 9.1%, and platelet use decreased from 20.5% to 13.4% (ptrend < 0.001 for all). A significant reduction occurred in deep sternal wound infection, reoperation for bleeding, renal failure, prolonged ventilation, initial ventilator time, and intensive care unit duration. The percentage of patients discharged home significantly increased (ptrend < 0.001). Mortality rates did not differ significantly (ptrend = 0.11). CONCLUSIONS: In a multicenter quality collaborative, increased attention to transfusion-related outcomes and blood conservation techniques, coincident with regular reporting and review of perioperative transfusion rates as a quality metric, was associated with a significant decrease in blood product utilization. These reductions were concurrent with significant improvement in most perioperative outcomes. This intervention was also safe, as it was not associated with any increases in mortality.

Analyzing "failure to rescue": is this an opportunity for outcome improvement in cardiac surgery?

BACKGROUND: In the setting of a statewide quality collaborative approach to the review of cardiac surgical mortalities in intensive care units (ICUs), variations in complication-related outcomes became apparent. Utilizing "failure to rescue" methodology (FTR; the probability of death after a complication), we compared FTR rates after adult cardiac surgery in low, medium, and high mortality centers from a voluntary, 33-center quality collaborative. METHODS: We identified 45,904 patients with a Society of Thoracic Surgeons predicted risk of mortality who underwent cardiac surgery between 2006 and 2010. The 33 centers were ranked according to observed-to-expected ratios for mortality and were categorized into 3 equal groups. We then compared rates of complications and FTR. RESULTS: Overall unadjusted mortality was 2.6%, ranging from 1.5% in the low-mortality group to 3.6% in the high group. The rate of 17 complications ranged from 19.1% in the low group to 22.9% in the high group while FTR rates were 6.6% in the low group, 10.4% in the medium group, and 13.5% in the high group (p < 0.001). The FTR rate was significantly better in the low mortality group for the majority of complications (11 of 17) with the most significant findings for cardiac arrest, dialysis, prolonged ventilation, and pneumonia. CONCLUSIONS: Low mortality hospitals have superior ability to rescue patients from complications after cardiac surgery procedures. Outcomes review incorporating a collaborative multi-hospital approach can provide an ideal opportunity to review processes that anticipate and manage complications in the ICU and help recognize and share "differentiators" in care.

Validation of a perfusion registry: methodological approach and initial findings.

Although regional and national registries exist to measure and report performance of cardiac surgical programs, few registries exist dedicated to the practice of cardiopulmonary bypass (CPB). We developed and implemented a cardiovascular perfusion registry (Perfusion Measures and outcomes [PERForm] Registry) within the structure of the Michigan Society of Thoracic and Cardiovascular Surgeons (MSTCVS) to improve our understanding of the practice of CPB. The PERForm Registry comprises data elements describing the practice of CPB. Fourteen medical centers within MSTCVS have voluntarily reported these data on procedures in which CPB is used. We validated the case count among procedures performed between January 1, 2011 to December 31, 2011, and validated the values among 20 fields at three medical centers. We queried database managers at all 14 medical centers to identify the infrastructure that contributed to best overall data collection performance. We found that 98% of all records submitted to the PERForm and 95% of those submitted to the Society of Thoracic Surgeons (STS) matched. We found quite favorable agreement in our audit of select fields (95.8%). Those centers with the most favorable performance in this validation study were more likely to use electronic data capture, have a perfusionist as the STS database manager, and have involvement of the STS database manager in the PERForm or STS databases. We successfully and accurately collected data concerning cardiovascular perfusion among 14 institutions in conjunction with the MSTCVS. Future efforts will focus on expanding data collection to all MSTCVS participating institutions as well as more broadly outside of Michigan.

A method to evaluate cardiac surgery mortality: phase of care mortality analysis.

BACKGROUND: This is a study of a method of mortality review, adopted by the Michigan Society of Thoracic and Cardiovascular Surgeons, to enhance understanding of mortality and potentially avoidable deaths after cardiac surgery, utilizing a voluntary statewide database. METHODS: A system to categorize mortality was developed utilizing a phase of care mortality analysis approach as well as providing criteria to classify mortality as potentially "avoidable." For each mortality, the operating surgeon categorized a cardiac surgery mortality trigger into 1 of 5 time frames: preoperative, intraoperative, intensive care unit (ICU), postoperative floor, and discharge. RESULTS: A total of 53,674 adult cardiac operations were performed from January 1, 2006 to June 30, 2010 with a crude mortality of 3.5% (1,905 of 53,674). Of the mortalities analyzed, 35% (618 of 1,780) were preoperative, 25% (451 of 1,780) were ICU, 19% (333 of 1,780) were intraoperative, 11% (198 of 1,780) were floor, and 10% (180 of 1,780) were discharge phase. "Avoidable" mortality triggers occurred in 53% (174 of 333) of the intraoperative, 41% (253 of 618) and (184 of 451) of the preoperative and ICU phases, 42% (83 of 198) of the floor, and 19% (35 of 180) of the discharge phase. Overall potentially avoidable mortality was 41% (729 of 1780). Thirty-six percent (644 of 1,780) of the mortalities were coronary artery bypass grafting patients and 29% (188 of 644) of these were in the preoperative phase, with a mean predicted risk of 16%. CONCLUSIONS: This analysis identifies the occurrence of potentially avoidable mortalities in the 4 hospital phases of care, with the largest absolute number of avoidable mortalities occurring in the preoperative phase. A focus on these phases of care provides significant opportunity for quality improvement initiatives. Utilizing phase of care mortality analysis stimulates surgeons and hospitals to develop and refine mortality reviews and provides a structured statewide platform for discussion, education, quality improvement, and enhanced outcomes.

Preoperative predicted risk does not fully explain the association between red blood cell transfusion and mortality in coronary artery bypass grafting.

OBJECTIVE: Perioperative red blood cell transfusion is associated with increased morbidity and mortality after coronary artery bypass grafting (CABG). Whether transfusion is a cause of these outcomes or serves as a surrogate for a high-risk patient population remains uncertain. This retrospective study tested the hypothesis that increased preoperative risk profile of patients receiving transfusion would explain the relationship between red blood cell transfusion and operative mortality in isolated CABG. METHODS: A total of 31,818 patients undergoing isolated CABG were entered into a statewide collaborative database between January 2006 and June 2010. With the Society of Thoracic Surgeons risk calculator, patient cohorts were stratified into 4 groups by predicted risk of mortality (PROM) of less than 2%, 2% to 5%, more than 5% to 10% and more than 10%. The association between blood transfusion and mortality was tested at each stratum with a χ(2) test. A Breslow-Day test for homogeneity of odds ratios was used to test whether the 4 odds ratios of the strata were similar, and a Cochran-Mantel-Haenszel test was used to test the association between blood transfusion and mortality while controlling for predicted risk mortality strata. RESULTS: In all, 17,720 (55.7%) of all patients were transfused during the hospitalization. Incidence of transfusion increased stepwise with risk level; 93.3% of patients with PROM greater than 10% received blood. Operative mortality was 2.1% overall, 0.6% among the 44.3% of patients who were not transfused, and 3.3% in the transfused group (odds ratio, 6.19; P < .0001). The association between blood transfusion and mortality was significant within each predicted risk stratum. Increased mortality associated with transfusion was statistically equivalent across all predicted risk strata (P = .1778). The association between blood transfusion and mortality for all patients lessened somewhat when controlling for PROM (odds ratio, 2.99 vs 6.19), yet remained highly significant (P < .0001). CONCLUSIONS: The association between red blood cell transfusion and mortality after CABG is highly significant and independent of increased preoperative risk status. The correlation persists after controlling for increased PROM.

A statewide quality collaborative for process improvement: internal mammary artery utilization.

BACKGROUND: The Michigan Society of Thoracic and Cardiovascular Surgeons (MSTCVS) Quality Collaborative is a voluntary, surgeon-directed quality initiative involving all cardiac surgery programs in Michigan. Understanding that internal mammary artery (IMA) use during coronary artery bypass grafting is an important process measure associated with improved outcomes, this analysis reviews our methodology to understand IMA use and increase appropriate IMA use statewide. METHODS: Adult cardiac Society of Thoracic Surgeons data were collected at each Michigan site and submitted quarterly to the Duke Clinical Research Institute and the MSTCVS. Seven cardiac surgery programs with IMA use less than 90% in isolated coronary artery bypass grafting were identified as low IMA users. An improvement plan was adopted at the state level and included quarterly monitoring of IMA use, documenting the rationale for IMA exclusion, evidence-based lectures, feedback letters to sites, and physician-led site visits if no improvement was noted. RESULTS: From 2005 through 2008, 29,114 patients underwent coronary artery bypass grafting in Michigan. Internal mammary artery utilization varied widely at the beginning of this investigation, ranging from 66.2% to 98.4%. Seven Michigan programs were identified as low IMA users. Using the MSTCVS Quality Collaborative's process-improvement plan, collectively the seven low IMA users increased IMA grafting from 82.0% to 92.7% (p < 0.0001). Michigan IMA use increased from 91.9% to 95.8% (p < 0.0001) and is now higher than The Society of Thoracic Surgeons' average. CONCLUSIONS: The MSTCVS Quality Collaborative identified programs with low IMA use and created an environment to enhance IMA utilization during coronary artery bypass grafting, a significant operative process. These findings illustrate the value of a statewide surgeon-directed quality initiative in improving processes and outcomes for patients.

Cardiac surgeons and the quality movement: the Michigan experience.

The Michigan Society of Thoracic and Cardiovascular Surgeons created a voluntary quality collaborative with all the cardiac surgeons in the state and all hospitals doing adult cardiac surgery. Utilizing this collaborative over the last 3 years and creating a unique relationship with a payor, an approach to processes and outcomes has produced improvements in the quality of care for cardiac patients in the state of Michigan.