Increasing healthcare resource utilization after coronary artery bypass graft surgery in the United States

Home Health Care Use and Outcomes After Coronary Artery Bypass Grafting Among Medicare Beneficiaries

BACKGROUND

Home health care (HHC) has been increasingly used to improve care transitions and avoid poor outcomes, but there is limited data on its use and efficacy following coronary artery bypass grafting. The purpose of this study was to describe HHC use and its association with outcomes among Medicare beneficiaries undergoing coronary artery bypass grafting.

METHODS

Retrospective analysis of 100% of Medicare fee-for-service files identified 77 331 beneficiaries undergoing coronary artery bypass grafting and discharged to home between July 2016 and December 2018. The primary exposure of HHC use was defined as the presence of paid HHC claims within 30 days of discharge. Hierarchical logistic regression identified predictors of HHC use and the percentage of variation in HHC use attributed to the hospital. Propensity-matched logistic regression compared mortality, readmissions, emergency department visits, and cardiac rehabilitation enrollment at 30 and 90 days after discharge between HHC users and nonusers.

RESULTS

A total of 26 751 (34.6%) of beneficiaries used HHC within 30 days of discharge, which was more common among beneficiaries who were older (72.9 versus 72.5 years), male (79.4% versus 77.4%), White (90.2% versus 89.2%), and not Medicare-Medicaid dual eligible (6.7% versus 8.8%). The median hospital-level rate of HHC use was 31.0% (interquartile range, 13.7%-54.5%) and ranged from 0% to 94.2%. Nearly 30% of the interhospital variation in HHC use was attributed to the discharging hospital (intraclass correlation coefficient, 0.296 [95% CI, 0.275-0.318]). Compared with non-HHC users, those using HHC were less likely to have a readmission or emergency department visit, were more likely to enroll in cardiac rehabilitation, and had modestly higher mortality within 30 or 90 days of discharge.

CONCLUSIONS

A third of Medicare beneficiaries undergoing coronary artery bypass grafting used HHC within 30 days of discharge, with wide interhospital variation in use and mixed associations with clinical outcomes and health care utilization.

Racial and Ethnic Disparities in Treatment of Critical Limb Ischemia: A National Perspective

Background Recent guidelines have emphasized the use of medical management, early diagnosis, and a multidisciplinary team to effectively treat patients with critical limb ischemia (CLI). Previous literature briefly highlighted the current racial disparities in its intervention. Herein, we analyze the trend over a 14-year time period to investigate whether the disparities gap in CLI management is closing. Methods and Results The National Inpatient Sample was queried between 2005 and 2018 for hospitalizations involving CLI. Nontraumatic amputations and revascularization were identified. Utilization trends of these procedures were compared between races (White, Black, Hispanic, Asian and Pacific Islander, Native American, and Other). Multivariable regression assessed differences in race regarding procedure usage. There were 6 904 562 admissions involving CLI in the 14-year study period. The rate of admissions in White patients who received any revascularization decreased by 0.23% (P<0.001) and decreased by 0.25% (P=0.025) for Asian and Pacific Islander patients. Among all patients, the annual rate of admission in White patients who received any amputation increased by 0.21% (P<0.001), increased by 0.19% (P=0.001) for Hispanic patients, and increased by 0.19% (P=0.012) for the Other race patients. Admissions involving Black, Hispanic, Asian and Pacific Islander, or Other race patients had higher odds of receiving any revascularization compared with White patients. All races had higher odds of receiving major amputation compared with White patients. Conclusions Our analysis highlights disparities in CLI treatment in our nationally representative sample. Non-White patients are more likely to receive invasive treatments, including major amputations and revascularization for CLI, compared with White patients.

Area Deprivation and Medicare Spending for Coronary Artery Bypass Grafting: Insights from Michigan

BACKGROUND

Prior work has established that high socioeconomic deprivation is associated with worse short- and long-term outcomes for coronary artery bypass graft (CABG) patients. The relationship between socioeconomic status and 90-day episode spending is poorly understood. In this observational cohort analysis, we evaluated whether socioeconomically disadvantaged patients were associated with higher expenditures during 90-day episodes of care following isolated CABG.

METHODS

We linked clinical registry data from 8,728 isolated CABG procedures from January 1st, 2012 to December 31st, 2018 to Medicare fee-for-service claims data. Our primary exposure variable was patients in the top decile of the Area Deprivation Index. Linear regression was used to compare risk-adjusted, price-standardized 90-day episode spending for deprived against non-deprived patients, as well as component spending categories: index hospitalization, professional services, post-acute care, and readmissions.

RESULTS

A total of 872 patients were categorized as being in the top decile. Mean 90-day episode spending for the 8,728 patients in the sample was $55,258 (standard deviation = $26,252). Socioeconomically deprived patients had higher overall 90-day spending compared to non-deprived patients ($61,579 vs. $54,557, difference = $3,003, p = 0.001). Spending was higher in socioeconomically deprived patients for index hospitalizations (difference = $1,284, p = 0.005), professional services (difference = $379, p = 0.002) and readmissions (difference = $1,188, p = 0.008). Inpatient rehabilitation was the only significant difference in post-acute care spending (difference = $469, p = 0.011).

CONCLUSIONS

Medicare spending was higher for socioeconomically deprived CABG in Michigan, indicating systemic disparities over and above patient demographic factors.

Dextran-based priming solution during cardiopulmonary bypass attenuates renal tubular injury-A secondary analysis of randomized controlled trial in adult cardiac surgery patients

BACKGROUND

Acute kidney injury (AKI) is a well-known complication after cardiac surgery and cardiopulmonary bypass (CPB). In the present secondary analysis of a blinded randomized controlled trial, we evaluated the effects of a colloid-based versus a conventional crystalloid-based prime on tubular injury and postoperative renal function in patients undergoing cardiac surgery with CPB.

METHODS

Eighty-four adult patients undergoing cardiac surgery with CPB were randomized to receive either a crystalloid- or colloid- (dextran 40) based CPB priming solution. The crystalloid solution was based on Ringer-Acetate plus mannitol. The tubular injury biomarker, N-acetyl-b-D-glucosaminidase (NAG), serum creatinine and diuresis were measured before, during and after CPB. The incidence of AKI was assessed according to the KDIGO criteria.

RESULTS

The urinary-NAG/urinary-creatinine ratio rose in both groups during and after CPB, with a more pronounced increase in the crystalloid group (p = .038). One hour after CPB, the urinary-NAG/urinary-creatinine ratio was 88% higher in the crystalloid group (4.7 ± 6.3 vs. 2.5 ± 2.7, p = .045). Patients that received the dextran 40-based priming solution had a significantly lower intraoperative diuresis (p < .001) compared to the crystalloid group. The incidence of AKI was 18% in the colloid and 22% in the crystalloid group (p = .66). Postoperative serum creatinine did not differ between groups.

CONCLUSIONS

In patients undergoing cardiac surgery with CPB, colloid-based priming solution (dextran 40) induced less renal tubular injury compared to a crystalloid-based priming solution. Whether a colloid-based priming solution will improve renal outcome in high-risk cardiac surgery, or not, needs to be evaluated in future studies on higher risk cardiac surgery patients.

IMPROV-ED trial: eHealth programme for faster recovery and reduced healthcare utilisation after CABG

Background

After coronary artery bypass grafting (CABG), healthcare utilisation is high and is partly unplanned. eHealth applications have been proposed to reduce healthcare consumption and to enable patients to get actively involved in their recovery. This way, healthcare expenses can be reduced and the quality of care can be improved.

Objectives

We aim to evaluate whether the use of an eHealth programme can reduce unplanned healthcare utilisation and improve mental and physical health in the first 6 weeks after discharge in patients who underwent CABG. In addition, patient satisfaction and use of the eHealth programme will be evaluated.

Methods

For this single-centre randomised controlled trial, at least 280 patients referred for CABG will be included at the preoperative outpatient clinic and randomised to an intervention or control group. The intervention group will have access to an eHealth programme, which consists of online educational videos developed by the Dutch Heart Foundation and postoperative video consultations with a physician. The control group will receive standard care and will not have access to the eHealth programme. The primary endpoint is healthcare utilisation; other endpoints include anxiety, duration of recovery, quality of life and patient satisfaction. Participants will complete several questionnaires at 6 time points during the study.

Results

Patient enrolment started in February 2020 and completion of the follow-up period is expected in August 2021.

Conclusion

This randomised trial was initiated to test the hypothesis that patients who are partaking in our eHealth programme use less unplanned care and experience a better quality of life, less anxiety and a faster recovery than controls.

Cell transfer-based immunotherapies in cancer: A review

In cell transfer therapy (CTT), immune cells such as innate immune-derived natural killer cells and dendritic cells as well as acquired immune-related T lymphocytes such as tumor-infiltrating lymphocytes and cytokine-activated or genetically modified peripheral blood T cells are used in the management of cancer. These therapies are increasingly becoming the most used treatment modality in cancer after tumor resection, chemotherapy, and radiotherapy. In adoptive cell transfer, the lymphocytes isolated from either a donor or the patient are modified ex vivo and reinfused to target malignant cells. Transferring in vitro-manipulated immune cells produces a continuous antitumor immune response. In this review, we evaluate the recent advances in CTT for the management of various malignancies.

Renal tubular injury during cardiopulmonary bypass as assessed by urinary release of N-acetyl-ß-D-glucosaminidase

BACKGROUND

Acute kidney injury (AKI) is a common complication with a major impact on morbidity and mortality after cardiac surgery with cardiopulmonary bypass (CPB). The aim of the present study was to perform a detailed analysis on the release of the tubular injury biomarker N-acetyl-b-D-glucosaminidase (NAG) during and early after CPB and to describe independent predictors of maximal tubular injury. We hypothesized that renal tubular injury occurs early after the onset of CPB.

METHODS

In this prospective observational study, we included 61 patients undergoing open cardiac surgery with an expected CPB duration exceeding 60 min. The urinary NAG levels were measured at 30 min intervals during CPB, as well as early (30 min) after CPB and post-operatively. Independent predictors of tubular injury were identified using an Interquantile multivariate regression model.

RESULTS

Already 30 min after the onset of CPB, NAG excretion was significantly increased (P < 0.001), followed by a sixfold peak increase after discontinuation of CPB (P < 0.001). In the multivariable regression model, CPB duration (P < 0.05) and the degree of rewarming during CPB (P < 0.05), were independent predictors of peak NAG excretion.

CONCLUSION

In cardiac surgery, a renal tubular cell injury is seen early after onset of CPB with a peak biomarker increase early after end of CPB. The magnitude of this tubular injury is independently related to CPB duration and the degree of rewarming. Efforts made to decrease the CPB duration and to avoid hypothermia and the need for rewarming may decrease the risk for tubular injury.

Effects of Cardiopulmonary Bypass on Renal Perfusion, Filtration, and Oxygenation in Patients Undergoing Cardiac Surgery

Background

Acute kidney injury is a common complication after cardiac surgery with cardiopulmonary bypass. The authors evaluated the effects of normothermic cardiopulmonary bypass on renal blood flow, glomerular filtration rate, renal oxygen consumption, and renal oxygen supply/demand relationship, i.e., renal oxygenation (primary outcome) in patients undergoing cardiac surgery.

Methods

Eighteen patients with a normal preoperative serum creatinine undergoing cardiac surgery procedures with normothermic cardiopulmonary bypass (2.5 l · min−1 · m−2) were included after informed consent. Systemic and renal hemodynamic variables were measured by pulmonary artery and renal vein catheters before, during, and after cardiopulmonary bypass. Arterial and renal vein blood samples were taken for measurements of renal oxygen delivery and consumption. Renal oxygenation was estimated from the renal oxygen extraction. Urinary N-acetyl-β-d-glucosaminidase was measured before, during, and after cardiopulmonary bypass.

Results

Cardiopulmonary bypass induced a renal vasoconstriction and redistribution of blood flow away from the kidneys, which in combination with hemodilution decreased renal oxygen delivery by 20%, while glomerular filtration rate and renal oxygen consumption were unchanged. Thus, renal oxygen extraction increased by 39 to 45%, indicating a renal oxygen supply/demand mismatch during cardiopulmonary bypass. After weaning from cardiopulmonary bypass, renal oxygenation was further impaired due to hemodilution and an increase in renal oxygen consumption, accompanied by a seven-fold increase in the urinary N-acetyl-β-d-glucosaminidase/creatinine ratio.

Conclusions

Cardiopulmonary bypass impairs renal oxygenation due to renal vasoconstriction and hemodilution during and after cardiopulmonary bypass, accompanied by increased release of a tubular injury marker.

High Postoperative Blood Pressure After Cardiac Surgery Is Associated With Acute Kidney Injury and Death

OBJECTIVES

Gaps and uncertainty exist regarding the understanding of optimal clinical goals for perioperative (ie, preoperative, intraoperative, and postoperative) blood pressure (BP) management in patients undergoing cardiac surgery and the consequences of achieving or failing to achieve those goals. In this setting, it is understood that preoperative hypertension is predictive of poor postoperative outcomes, with a growing appreciation that current, clinically acceptable changes in intraoperative BP also may be associated independently with adverse short- and long-term outcomes. In contrast, the impact of postoperative BP on outcomes after cardiac surgery remains less clear.

DESIGN

This study was a retrospective outcome analysis.

SETTING

The study included all cardiac surgery patients cared for at a single institution over a 7-year period. Consequences of the success or failure of meeting postoperative BP targets on medical outcomes and health resource utilization were evaluated.

RESULTS

The study comprised 5,225 patients. Hypertensive postoperative patients experienced a higher in-hospital mortality rate compared with matched-case normotensive patients (4.97% v 1.32%, p<0.001) and a longer hospital stay (p = 0.024). In hypertensive patients, serum creatinine levels from postoperative day 1 through postoperative day 7 were increased compared with baseline and postoperative renal dysfunction according to the Kidney Disease: Improving Global Outcomes criteria occurred significantly more often (25.3% v 19.7%, p = 0.027).

CONCLUSIONS

Postoperative hypertension is associated with compromised outcome as reflected by higher mortality, longer length of stay, and higher incidence of renal dysfunction.

[Strategies for prevention of acute kidney injury in cardiac surgery: an integrative review]

Acute kidney injury is a common complication after cardiac surgery and is associated with increased morbidity and mortality and increased length of stay in the intensive care unit. Considering the high prevalence of acute kidney injury and its association with worsened prognosis, the development of strategies for renal protection in hospitals is essential to reduce the associated high morbidity and mortality, especially for patients at high risk of developing acute kidney injury, such as patients who undergo cardiac surgery. This integrative review sought to assess the evidence available in the literature regarding the most effective interventions for the prevention of acute kidney injury in patients undergoing cardiac surgery. To select the articles, we used the CINAHL and MedLine databases. The sample of this review consisted of 16 articles. After analyzing the articles included in the review, the results of the studies showed that only hydration with saline has noteworthy results in the prevention of acute kidney injury. The other strategies are controversial and require further research to prove their effectiveness.

National Trends in Hospital Readmission Rates among Medicare Fee-for-Service Survivors of Mitral Valve Surgery, 1999-2010

Background

Older patients who undergo mitral valve surgery (MVS) have high 1-year survival rates, but little is known about the experience of survivors. Our objective was to determine trends in 1-year hospital readmission rates and length of stay (LOS) in these individuals.

Methods

We included 100% of Medicare Fee-for-Service patients ≥65 years of age who underwent MVS between 1999–2010 and survived to 1 year (N = 146,877). We used proportional hazards regression to analyze the post-MVS 1-year readmission rate in each year, mean hospital LOS (after index admission), and readmission rates by subgroups (age, sex, race).

Results

The 1-year survival rate among patients undergoing MVS was 81.3%. Among survivors, 49.1% experienced a hospital readmission within 1 year. The post-MVS 1-year readmission rate declined from 1999–2010 (49.5% to 46.9%, P<0.01), and mean hospital LOS decreased from 6.2 to 5.3 (P<0.01). Readmission rates were highest in oldest patients, but declined in all age subgroups (65–74: 47.4% to 44.4%; 75–84: 51.4% to 49.2%, ≥85: 56.4% to 50.0%, all P<0.01). There were declines in women and men (women: 51.7% to 50.8%, P<0.01; men: 46.9% to 43.0%, P<0.01), and in whites and patients of other race, but not in blacks (whites: 49.0% to 46.2%, P<0.01; other: 55.0% to 48.9%, P<0.01; blacks: 58.1% to 59.0%, P = 0.18).

Conclusions

Among older adults surviving MVS to 1 year, slightly fewer than half experience a hospital readmission. There has been a modest decline in both the readmission rate and LOS over time, with worse outcomes in women and blacks.

Risk of not being discharged home after isolated coronary artery bypass graft operations

BACKGROUND

The age and risk profile of patients undergoing isolated coronary artery bypass grafting (CABG) is increasing, which will likely increase the proportion of CABG patients discharged to nursing homes, rehabilitation, or long-term care. Because discharge disposition can be important to a patient's treatment goals, developing and using predictive tools will improve informed treatment decision making. We examined the utility of The Society of Thoracic Surgeons (STS) risk of mortality score in predicting discharge disposition after CABG.

METHODS

From January 1, 2004 to October 31, 2011, 5,119 patients underwent isolated CABG at The Heart Hospital Baylor Plano or Baylor University Medical Center (Texas) and were discharged alive. The association between STS risk of mortality and discharge to nursing home, rehabilitation, or long-term care was assessed using multivariable logistic regression, adjusted for age, body surface area, marital status, site, and year of operation.

RESULTS

At discharge, 216 patients (4.21%) went to nursing homes, 153 (2.99%) to rehabilitation, and 115 (2.25%) to long-term care. The STS risk of mortality score was significantly positively associated with discharge status (p < 0.001). Patients with 1%, 2%, 3%, 4%, and 5% STS risk of mortality had 11.25%, 22.10%, 29.45%, 35.00%, and 38.50% probability, respectively, of not being discharged home. When the STS risk of mortality was 5%, the risk of not being discharged home was 47.9% for off-pump patients and 38.10% for on-pump patients.

CONCLUSIONS

STS risk score is strongly associated with CABG discharge status. Patients with a risk score exceeding 2 are at high risk (>22%) of not being discharged home. This risk should be discussed when treatment decisions are being made.

Robotics in cardiac surgery: past, present, and future

Robotic cardiac operations evolved from minimally invasive operations and offer similar theoretical benefits, including less pain, shorter length of stay, improved cosmesis, and quicker return to preoperative level of functional activity. The additional benefits offered by robotic surgical systems include improved dexterity and degrees of freedom, tremor-free movements, ambidexterity, and the avoidance of the fulcrum effect that is intrinsic when using long-shaft endoscopic instruments. Also, optics and operative visualization are vastly improved compared with direct vision and traditional videoscopes. Robotic systems have been utilized successfully to perform complex mitral valve repairs, coronary revascularization, atrial fibrillation ablation, intracardiac tumor resections, atrial septal defect closures, and left ventricular lead implantation. The history and evolution of these procedures, as well as the present status and future directions of robotic cardiac surgery, are presented in this review.

Impact of length of stay after coronary bypass surgery on short-term readmission rate: an instrumental variable analysis

OBJECTIVE

: To determine the effect of postoperative length of stay (LOS) on 30-day readmission after coronary artery bypass surgery.

DATA SOURCES/STUDY SETTING

: We analyzed a final database consisting of Medicare claims of a cohort (N=157,070) of all fee-for-service beneficiaries undergoing bypass surgery during 2007-2008, the American Hospital Association annual survey file, and the rural urban commuting area file.

STUDY DESIGN

: We regressed the probability of 30-day readmission on postoperative LOS using (1) a (naive) logit model that controlled for observed patient and hospital covariates only; and (2) a residual inclusion instrumental variable (IV) logit model that further controlled for unobserved confounding. The IV was defined using a measure of the hospital's risk-adjusted LOS for patients admitted for gastrointestinal hemorrhage.

PRINCIPAL FINDINGS

: The naive logit model predicted that a 1-day reduction in median postoperative LOS (ie, from a median of 6-5 d) lowered the 30-day readmission rate by 2 percentage points. The IV model predicted that a 1-day reduction in median postoperative LOS increased 30-day readmission rate by 3 percentage points.

CONCLUSIONS

: The findings indicate that a reduction in postoperative LOS is associated with an increased risk for 30-day readmission among Medicare patients undergoing bypass surgery, after both observed and unobserved confounding effects are corrected.

Trends in acute kidney injury, associated use of dialysis, and mortality after cardiac surgery, 1999 to 2008

BACKGROUND

The development of acute kidney injury (AKI) after cardiac surgery is associated with significant mortality, morbidity, and cost. The last decade has seen major changes in the complexity of cardiac surgical candidates and in the number and type of cardiac surgical procedures being performed.

METHODS

Using data from the Nationwide Inpatient Sample, we determined the annual rates of AKI, AKI requiring dialysis (AKI-D), and inpatient mortality after cardiac surgery in the United States in the years 1999 through 2008.

RESULTS

Inpatient mortality with AKI and AKI-D decreased from 27.9% and 45.9%, respectively, in 1999 to 12.8% and 35.3%, respectively, in 2008. Compared with 1999, the odds of AKI and AKI-D in 2008, adjusted for demographic and clinical factors, were 3.30 (95% confidence interval [CI]: 2.89 to 3.77) and 2.23 (95% CI: 1.78 to 2.80), respectively. Corresponding adjusted odds of death associated with AKI and AKI-D were 0.31 (95% CI: 0.26 to 0.36) and 0.47 (95% CI: 0.34 to 0.65.) Taken together, the attributable risks for death after cardiac surgery associated with AKI and AKI-D increased from 30% and 5%, respectively, in 1999 to 47% and 14%, respectively, in 2008.

CONCLUSIONS

In sum, despite improvements in individual patient outcomes over the decade 1999 to 2008, the population contribution of AKI and AKI-D to inpatient mortality after surgery increased over the same period.

Preoperative statin use and postoperative acute kidney injury

BACKGROUND

Acute kidney injury is a frequent postoperative complication that confers increased mortality, morbidity, and costs. The purpose of this study was to evaluate whether preoperative statin use is associated with a decreased risk of postoperative acute kidney injury.

METHODS

We assembled a retrospective cohort of 98,939 patients who underwent a major open abdominal, cardiac, thoracic, or vascular procedure between 2000 and 2010. Statin users were pair-matched to nonusers on the basis of surgery type, baseline kidney function, days from admission until surgery, and propensity score based on demographics, comorbid conditions, and concomitant medications. Acute kidney injury was defined based on changes in serum creatinine measurements applying Acute Kidney Injury Network and Risk-Injury-Failure staging systems, and on the need for renal replacement therapy. Associations between statin use and acute kidney injury were estimated by conditional logistic regression.

RESULTS

Across various acute kidney injury definitions, statin use was consistently associated with a decreased risk: adjusted odds ratios (95% confidence intervals) varied from 0.74 (0.58-0.95) to 0.80 (0.71-0.90). Associations were similar among diabetics and nondiabetics, and across strata of baseline kidney function. The protective association of statins was most pronounced among patients undergoing vascular surgery and least among patients undergoing cardiac surgery.

CONCLUSIONS

Preoperative statin use is associated with a decreased risk of postoperative acute kidney injury. Future randomized clinical trials are needed to determine causality.

Preventing acute kidney injury after cardiac surgery

PURPOSE OF REVIEW

Acute kidney injury (AKI) is a serious complication that significantly increases morbidity, mortality and cost of care after cardiac surgery. In this review we identify the current literature that addresses strategies for renal protection and the prevention of AKI after cardiac surgery.

RECENT FINDINGS

Even with aggressive medical care and renal replacement therapy (RRT) the morbidity, mortality and cost of postoperative AKI after cardiac surgery is substantial. An emphasis on preventive strategies would therefore appear to be the most cost-effective approach. Recent literature offers hope that as our understanding of the pathogenesis of AKI after cardiac surgery continues to improve, new directions for the prevention and amelioration of AKI will emerge. Approaches to the prevention of postoperative AKI include careful risk stratification of patients, allowing adequate recovery following a prior AKI, consideration of less extensive surgical procedures, avoidance of cardiopulmonary bypass, minimizing injury from radiocontrast dyes or other nephrotoxic agents, and optimizing cardiovascular function and oxygen delivery. Early identification of AKI and prompt, judicious application of RRT may also improve outcomes. Interest in pharmacologic renoprotection is currently directed toward statins and sodium bicarbonate.

SUMMARY

Postoperative AKI is a serious complication after cardiac surgery. Therapeutic interventions and RRT have limited influence on the outcome of AKI, and a preventive strategy remains the mainstay to attenuate its impact.