Using a quality improvement initiative to reduce acute kidney injury during on-pump coronary artery bypass grafting.

INTRODUCTION: In response to a perceived high incidence of acute kidney injury following cardiopulmonary bypass at our institution, a quality improvement initiative consisting of a systematic change to a delivered oxygen (DO2) goal-directed perfusion practice was implemented. We sought to maintain DO2 > 270 mL/min/m2 to reduce the incidence of acute kidney injury. METHODS: 'The study population included all patients receiving isolated, non-emergent, on-pump coronary artery bypass grafting from January 2015 through December 2018, excluding patients requiring preoperative hemodialysis. DO2 goal-directed perfusion was instituted in February 2017. Acute kidney injury was defined using Acute Kidney Injury Network criteria. RESULTS: The pre-goal-directed perfusion cohort included 257 patients, and the post-goal-directed perfusion cohort included 226 patients. The DO2 was significantly higher in the post-goal-directed perfusion group (p < 0.001). Postoperative change in serum creatinine and incidence of acute kidney injury were significantly lower in the post-goal-directed perfusion group (p < 0.001, p = 0.001, respectively). Estimation with probit and ordered probit models support these findings. CONCLUSION: This initiative confirms previous assertions that DO2 is a critical intraoperative parameter and should direct perfusion intervention accordingly.

Serious mental illnesses associated with receipt of surgery in retrospective analysis of patients in the Veterans Health Administration.

BACKGROUND: The STOPP study (Surgical Treatment Outcomes for Patients with Psychiatric Disorders) analyzed variation in rates and types of major surgery by serious mental illness status among patients treated in the Veterans Health Administration (VA). VA patients are veterans of United States military service who qualify for federal care by reason of disability, special service experiences, or poverty. METHODS: STOPP conducted a secondary data analysis of medical record extracts for seven million VA patients treated Oct 2005-Sep 2009. The retrospective study aggregated inpatient surgery events, comorbid diagnoses, demographics, and postoperative 30-day mortality. RESULTS: Serious mental illness -- schizophrenia, bipolar disorder, posttraumatic stress disorder, or major depressive disorder, was identified in 12 % of VA patients. Over the 4-year study period, 321,131 patients (4.5 %) underwent surgery with same-day preoperative or immediate post-operative admission including14 % with serious mental illness. Surgery patients were older (64 vs. 61 years) and more commonly African-American, unmarried, impoverished, highly disabled (24 % vs 12 % were Priority 1), obese, with psychotic disorder (4.3 % vs 2.9 %). Among surgery patients, 3.7 % died within 30 days postop. After covariate adjustment, patients with pre-existing serious mental illness were relatively less likely to receive surgery (adjusted odds ratios 0.4-0.7). CONCLUSIONS: VA patients undergoing major surgery appeared, in models controlling for comorbidity and demographics, to disproportionately exclude those with serious mental illness. While VA preferentially treats the most economically and medically disadvantaged veterans, the surgery subpopulation may be especially ill, potentially warranting increased postoperative surveillance.

Clinical and angiographic risk stratification and differential impact on treatment outcomes in the Bypass Angioplasty Revascularization Investigation 2 Diabetes (BARI 2D) trial.

BACKGROUND: The Bypass Angioplasty Revascularization Investigation 2 Diabetes (BARI 2D) trial assigned patients with type 2 diabetes mellitus to prompt coronary revascularization plus intensive medical therapy versus intensive medical therapy alone and reported no significant difference in mortality. Among patients selected for coronary artery bypass graft surgery, prompt coronary revascularization was associated with a significant reduction in death/myocardial infarction/stroke compared with intensive medical therapy. We hypothesized that clinical and angiographic risk stratification would affect the effectiveness of the treatments overall and within revascularization strata. METHODS AND RESULTS: An angiographic risk score was developed from variables assessed at randomization; independent prognostic factors were myocardial jeopardy index, total number of coronary lesions, prior coronary revascularization, and left ventricular ejection fraction. The Framingham Risk Score for patients with coronary disease was used to summarize clinical risk. Cardiovascular event rates were compared by assigned treatment within high-risk and low-risk subgroups. Overall, no outcome differences between the intensive medical therapy and prompt coronary revascularization groups were seen in any risk stratum. The 5-year risk of death/myocardial infarction/stroke was 36.8% for intensive medical therapy compared with 24.8% for prompt coronary revascularization among the 381 coronary artery bypass graft surgery-selected patients in the highest angiographic risk tertile (P=0.005); this treatment effect was amplified in patients with both high angiographic and high Framingham risk (47.3% intensive medical therapy versus 27.1% prompt coronary revascularization; P=0.010; hazard ratio=2.10; P=0.009). Treatment group differences were not significant in other clinical-angiographic risk groups within the coronary artery bypass graft surgery stratum, or in any subgroups within the percutaneous coronary intervention stratum. CONCLUSION: Among patients with diabetes mellitus and stable ischemic heart disease, a strategy of prompt coronary artery bypass graft surgery significantly reduces the rate of death/myocardial infarction MI/stroke in those with extensive coronary artery disease or impaired left ventricular function. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00006305.

Surgical and Transcatheter Mitral Valve Therapy: Medicare Utilization and Reimbursement.

BACKGROUND: We aimed to examine trends in the utilization and reimbursement of surgical and transcatheter mitral valve therapies and their changing relationship. METHODS: A query of administrative data on US Medicare beneficiaries undergoing mitral valve therapy was conducted from 2015 to 2020 using the Centers for Medicare and Medicaid Services Part B National Summary Data File. Inflation adjustment was to the 2020 Consumer Price Index. Trend analysis was quantified with growth rate and simple linear regression calculations. RESULTS: The annual number of all mitral valve procedures remained constant. Transcatheter mitral valve therapies increased by 313% with an increase of 1552 cases per year (P < .001), whereas surgical mitral valve therapies decreased by 31.4% with a decline of 1446 procedures per year (P = .004). As a proportion of all mitral valve therapies, surgical therapies decreased from 91.8% to 65.0%. Annual Medicare reimbursements for transcatheter and surgical mitral valve therapies mirrored the annual procedural trends. For transcatheter mitral valve therapies, per-case reimbursement decreased by 14.1% ($1283.18 to $1102.88), and for surgical mitral valve therapies, per-case reimbursement decreased by 3.8% ($1480.65 to $1424.57). CONCLUSIONS: Medicare utilization of mitral valve therapies has been stable in recent years, with growth of transcatheter volumes offset by a decrease in surgical volumes. This suggests that transcatheter therapy availability has not expanded the pool of patients with access to therapy. Nonetheless, case reimbursements decreased for both modalities.

A randomized trial of therapies for type 2 diabetes and coronary artery disease.

BACKGROUND: Optimal treatment for patients with both type 2 diabetes mellitus and stable ischemic heart disease has not been established. METHODS: We randomly assigned 2368 patients with both type 2 diabetes and heart disease to undergo either prompt revascularization with intensive medical therapy or intensive medical therapy alone and to undergo either insulin-sensitization or insulin-provision therapy. Primary end points were the rate of death and a composite of death, myocardial infarction, or stroke (major cardiovascular events). Randomization was stratified according to the choice of percutaneous coronary intervention (PCI) or coronary-artery bypass grafting (CABG) as the more appropriate intervention. RESULTS: At 5 years, rates of survival did not differ significantly between the revascularization group (88.3%) and the medical-therapy group (87.8%, P=0.97) or between the insulin-sensitization group (88.2%) and the insulin-provision group (87.9%, P=0.89). The rates of freedom from major cardiovascular events also did not differ significantly among the groups: 77.2% in the revascularization group and 75.9% in the medical-treatment group (P=0.70) and 77.7% in the insulin-sensitization group and 75.4% in the insulin-provision group (P=0.13). In the PCI stratum, there was no significant difference in primary end points between the revascularization group and the medical-therapy group. In the CABG stratum, the rate of major cardiovascular events was significantly lower in the revascularization group (22.4%) than in the medical-therapy group (30.5%, P=0.01; P=0.002 for interaction between stratum and study group). Adverse events and serious adverse events were generally similar among the groups, although severe hypoglycemia was more frequent in the insulin-provision group (9.2%) than in the insulin-sensitization group (5.9%, P=0.003). CONCLUSIONS: Overall, there was no significant difference in the rates of death and major cardiovascular events between patients undergoing prompt revascularization and those undergoing medical therapy or between strategies of insulin sensitization and insulin provision. (ClinicalTrials.gov number, NCT00006305.)

Smart Drain for Post-Cardiac Surgery Left Ventricular Volumes Evaluated in Large Animal Models.

BACKGROUND: Open heart surgeries for coronary arterial bypass graft and valve replacements are performed on 400,000 Americans each year. Unexplained hypotension during recovery causes morbidity and mortality through cerebral, kidney, and coronary hypoperfusion. An early detection method that distinguishes between hypovolemia and decreased myocardial function before onset of hypotension is desirable. We hypothesized that admittance measured from a modified pericardial drain can detect changes in left ventricular end-systolic, end-diastolic, and stroke volumes. METHODS: Admittance was measured from 2 modified pericardial drains placed in 7 adult female dogs using an open chest preparation, each with 8 electrodes. The resistive and capacitive components of the measured admittance signal were used to distinguish blood and muscle components. Admittance measurements were taken from 12 electrode configurations in each experiment. Left ventricular preload was reduced by inferior vena cava occlusion. Physiologic response to vena cava occlusion was measured by aortic pressure, aortic flow, left ventricle diameter, left ventricular wall thickness, and electrocardiogram. RESULTS: Admittance successfully detected a drop in left ventricular end-diastolic volume (P < .001), end-systolic volume (P < .001), and stroke volume (P < .001). Measured left ventricular muscle resistance correlated with crystal-derived left ventricular wall thickness (R2 = 0.96), validating the method's ability to distinguish blood from muscle components. CONCLUSIONS: Admittance measured from chest tubes can detect changes in left ventricular end-systolic, end-diastolic, and stroke volumes and may therefore have diagnostic value for unexplained hypotension.

Trabecular cutting: a novel surgical therapy to increase diastolic compliance.

Heart failure with preserved ejection fraction (HFpEF) is a common cause of hospital admission in patients over 65 yr old and has high mortality. HFpEF is characterized by left ventricular (LV) hypertrophy that reduces compliance. Current HFpEF therapies control symptoms, but no existing medications or therapies can sustainably increase LV compliance. LV trabeculae develop hypertrophy and fibrosis that contribute to reduced LV compliance. This study expands our previous results in ex vivo human hearts to show that severing LV trabeculae increases diastolic compliance in an ex vivo working rabbit heart model. Trabecular cutting was performed in ex vivo rabbit hearts set up in a working heart perfusion system perfused with oxygenated Krebs-Henseleit buffer. A hook was inserted in the LV to cut trabeculae. End-systolic and end-diastolic pressure-volume relationships during transient preload reduction were recorded using an admittance catheter in the following three groups: control (no cutting; n = 9), mild cutting (15 cuts; n = 5), and aggressive cutting (30 cuts; n = 5). In a second experiment, each heart served as its own control. Hemodynamic data were recorded before and after trabecular cutting (n = 10) or sham cutting (n = 5) within the same heart. In the first experiments, trabecular cutting did not affect systolic function (P > 0.05) but significantly increased overall diastolic compliance (P = 0.009). Greater compliance was seen as trabecular cutting increased (P = 0.002, r2 = 0.435). In the second experiment, significant increases in systolic function (P = 0.048) and diastolic compliance (P = 0.002) were seen after trabecular cutting compared with baseline. In conclusion, trabecular cutting significantly increases diastolic compliance without reducing systolic function.NEW & NOTEWORTHY We postulate that, in mammalian hearts, free-running trabeculae carneae exist to provide tensile support to the left ventricle and minimize diastolic wall stress. Because of hypertrophy and fibrosis of trabeculae in patients with left ventricular hypertrophy, this supportive role can become pathologic, worsening diastolic compliance. We demonstrate a novel operation involving cutting trabeculae as a method to acutely increase diastolic compliance in patients presenting with heart failure and diastolic dysfunction to improve their left ventricle compliance.

BARI 2D: A Reanalysis Focusing on Cardiovascular Events.

OBJECTIVE: To reanalyze the Bypass Angioplasty Revascularization Investigation 2 Diabetes trial using a new composite cardiovascular disease (CVD) outcome to determine how best to treat patients with type 2 diabetes mellitus and stable coronary artery disease. PATIENTS AND METHODS: From January 1, 2001, to November 30, 2008, 2368 patients with type 2 diabetes mellitus and angiographically proven coronary artery disease were randomly assigned to insulin-sensitizing (IS) or insulin-providing (IP) therapy and simultaneously to coronary revascularization (REV) or no or delayed REV (intensive medical therapy [MED]), with all patients receiving intensive medical treatment. The outcome of this analysis was a composite of 8 CVD events. RESULTS: Four-year Kaplan-Meier rates for the composite CVD outcome were 35.8% (95% CI, 33.1%-38.5%) with IS therapy and 41.6% (95% CI, 38.7%-44.5%) with IP therapy (P=.004). Much of this difference was associated with lower in-trial levels of fibrinogen, C-reactive protein, and hemoglobin A1c with IS therapy. Four-year composite CVD rates were 32.7% (95% CI, 30.0%-35.4%) with REV and 44.7% (95% CI, 41.8%-47.6%) with MED (P<.001). A beneficial effect of IS vs IP therapy was present with REV (27.7%; 95% CI, 24.0%-31.4% vs 37.5%; 95% CI, 33.6%-41.4%; P<.001), but not with MED (43.6%; 95% CI, 39.5%-47.7% vs 45.7%; 95% CI, 41.6%-49.8%; P=.37) (homogeneity, P=.05). This interaction between IS therapy and REV was limited to participants preselected for coronary artery bypass grafting (CABG). The lowest composite CVD rates occurred in patients preselected for CABG and assigned to IS therapy and REV (17.3%; 95% CI, 11.8%-22.8%). CONCLUSION: In the Bypass Angioplasty Revascularization Investigation 2 Diabetes trial, the IS treatment strategy and the REV treatment strategy each reduces cardiovascular events. The combination of IS drugs and CABG results in the lowest risk of subsequent CVD events. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00006305.

Contemporary surgical outcomes of venous tumour thrombectomy managed with intraoperative Doppler ultrasound for kidney cancer.

INTRODUCTION: Radical nephrectomy (RN) with venous tumour thrombectomy (VTT) carries a significant morbidity and mortality risk. Examination of a contemporary single-institution series permits the development of a management algorithm and an audit its results. We report outcomes following the use of intraoperative colour Doppler ultrasound and our surgical pathway. METHODS: We retrospectively reviewed the records of all patients who underwent RN with VTT for kidney cancer between January 1, 2013 and October 1, 2016. Surgical complications, postoperative complications (Clavien-Dindo classification ≥3), 90-day readmission rates, and outcomes are reported. Multivariate linear regression, logistic regression, and Cox proportional hazard modelling were used to identify associations. RESULTS: Fifty-eight patients underwent RN with VTT. Of these, 26 (45%) patients had Mayo Clinic level III or IV thrombus and nineteen required venovenous/cardiopulmonary bypass. Three patients required patch grafting. The median length of hospital stay was eight days and there were 20 major complications. The 30-day readmission rate was 21% and the 90-day mortality rate was 8.9%. In multivariate analysis, low serum albumin and age-adjusted Charlson comorbidity score predicted length of stay. Increased intraoperative blood loss was significantly associated with increasing body mass index, serum creatinine, tumour thrombus level, and a history of significant weight loss >9.1kg. Low serum hematocrit predicted 90-day mortality. CONCLUSIONS: Intraoperative colour Doppler ultrasound is a useful tool and can facilitate caval preservation. Caval grafting can be avoided in most cases. Venovenous bypass can be avoided in many level III cases. Early therapeutic anticoagulation should be instituted with caution.

On-pump versus off-pump coronary artery bypass graft surgery among patients with type 2 diabetes in the Bypass Angioplasty Revascularization Investigation 2 Diabetes trial.

OBJECTIVES: Conclusive evidence is lacking regarding the benefits and risks of performing off-pump versus on-pump coronary artery bypass graft (CABG) for patients with diabetes. This study aims to compare clinical outcomes after off-pump and on-pump procedures for patients with diabetes. METHODS: The Bypass Angioplasty Revascularization Investigation 2 Diabetes (BARI 2D) trial enrolled patients with type 2 diabetes and documented coronary artery disease, 615 of whom underwent CABG during the trial. The procedural complications, 30-day outcomes, long-term clinical and functional outcomes were compared between the off-pump and on-pump groups overall and within a subset of patients matched on propensity score. RESULTS: On-pump CABG was performed in 444 (72%) patients, and off-pump CABG in 171 (28%). The unadjusted 30-day rate of death/myocardial infarction (MI)/stroke was significantly higher after off-pump CABG (7.0 vs 2.9%, P = 0.02) despite fewer complications (10.3 vs 20.7%, P = 0.003). The long-term risk of death [adjusted hazard ratio (aHR): 1.41, P = 0.2197] and major cardiovascular events (death, MI or stroke) (aHR: 1.47, P = 0.1061) did not differ statistically between the off-pump and on-pump patients. Within the propensity-matched sample (153 pairs), patients who underwent off-pump CABG had a higher risk of the composite outcome of death, MI or stroke (aHR: 1.83, P = 0.046); the rates of procedural complications and death did not differ significantly, and there were no significant differences in the functional outcomes. CONCLUSIONS: Patients with diabetes had greater risk of major cardiovascular events long-term after off-pump CABG than after on-pump CABG.