Short- and long-term outcomes of coronary artery bypass grafting or drug-eluting stent implantation for multivessel coronary artery disease in patients with chronic kidney disease

Optimal revascularization for complex coronary artery disease

Patients with major or symptomatic coronary artery disease (CAD) commonly undergo revascularization--either with CABG surgery, which has been the mainstay of revascularization for more than half a century, or with percutaneous coronary intervention (PCI), which has become the more-commonly used strategy in the past decade. PCI has been tested in more randomized clinical trials than any other procedure in contemporary practice. In general, PCI is the preferred option for treating patients with simple coronary artery lesions and CABG surgery remains the standard of care for patients with complex CAD. Technical advancements in PCI and CABG surgery make comparisons of historical data for these strategies difficult. In this Review, we evaluate the evidence-based use of PCI and CABG surgery in treating patients with multivessel and unprotected left main stem disease and for specific patient groups, including those with diabetes mellitus, chronic heart failure, or chronic kidney disease. Finally, we highlight the available tools to aid decision-making, including clinical guidelines, risk scoring systems, and the role of the 'heart team'.

Chronic kidney disease and cardiovascular risk: epidemiology, mechanisms, and prevention

Since the first description of the association between chronic kidney disease and heart disease, many epidemiological studies have confirmed and extended this finding. As chronic kidney disease progresses, kidney-specific risk factors for cardiovascular events and disease come into play. As a result, the risk for cardiovascular disease is notably increased in individuals with chronic kidney disease. When adjusted for traditional cardiovascular risk factors, impaired kidney function and raised concentrations of albumin in urine increase the risk of cardiovascular disease by two to four times. Yet, cardiovascular disease is frequently underdiagnosed and undertreated in patients with chronic kidney disease. This group of patients should, therefore, be acknowledged as having high cardiovascular risk that needs particular medical attention at an individual level. This view should be incorporated in the development of guidelines and when defining research priorities. Here, we discuss the epidemiology and pathophysiological mechanisms of cardiovascular risk in patients with chronic kidney disease, and discuss methods of prevention.

Optimal strategy of coronary revascularization in chronic kidney disease patients: a meta-analysis

BACKGROUND

Patients with chronic kidney disease (CKD) have high risks of coronary artery disease (CAD). Coronary revascularization is beneficial for long-term survival, but the optimal strategy remains still controversial.

METHODS

We searched studies that have compared percutaneous coronary intervention (PCI) and coronary artery bypass graft (CABG) for revascularization of the coronary arteries in CKD patients. Short-term (30 days or in-hospital) mortality, long-term (at least 12 months) all-cause mortality, cardiac mortality and the incidence of late myocardial infarction and recurrence of revascularization were estimated.

RESULTS

28 studies with 38,740 patients were included. All were retrospective studies from 1977 to 2012. Meta-analysis showed that PCI group had lower short-term mortality (OR 0.55, 95% CI 0.41 to 0.73, P<0.01), but had higher long-term all-cause mortality (OR 1.29, 95% CI 1.23 to 1.35, P<0.01). Higher cardiac mortality (OR 1.08, 95% CI 1.01 to 1.15, P<0.05), higher incidence of late myocardial infarction (OR 1.78, 95% CI 1.65 to 1.91, P<0.01) and recurring revascularization rate (OR 2.94, 95%CI 2.15 to 4.01, P<0.01) is found amongst PCI treated patients compared to CABG group.

CONCLUSIONS

CKD patients with CAD received CABG had higher risk of short-term mortality but lower risks of long-term all-cause mortality, cardiac mortality and late myocardial infarction compared to PCI. This could be due to less probable repeated revascularization.

Comparative effectiveness of coronary artery bypass grafting and percutaneous coronary intervention for multivessel coronary disease in a community-based population with chronic kidney disease

BACKGROUND

Randomized clinical trials comparing coronary artery bypass grafting (CABG) with percutaneous coronary intervention (PCI) have largely excluded patients with chronic kidney disease (CKD), leading to uncertainty about the optimal coronary revascularization strategy. We sought to test the hypothesis that an initial strategy of CABG would be associated with lower risks of long-term mortality and cardiovascular morbidity compared with PCI for the treatment of multivessel coronary heart disease in the setting of CKD.

METHODS

We created a propensity score-matched cohort of patients aged ≥30 years with no prior dialysis or renal transplant who received multivessel coronary revascularization between 1996 and 2008 within a large integrated health care delivery system in northern California. We used extended Cox regression to examine death from any cause, acute coronary syndrome, and repeat revascularization.

RESULTS

Coronary artery bypass grafting was associated with a significantly lower adjusted rate of death than PCI across all strata of estimated glomerular filtration rate (eGFR) (in mL/min per 1.73 m(2)): the adjusted hazard ratio (HR) was 0.81, 95% CI 0.68 to 1.00 for patients with eGFR ≥60; HR 0.73 (CI 0.56-0.95) for eGFR of 45 to 59; and HR 0.87 (CI 0.67-1.14) for eGFR <45. Coronary artery bypass grafting was also associated with significantly lower rates of acute coronary syndrome and repeat revascularization at all levels of eGFR compared with PCI.

CONCLUSIONS

Among adults with and without CKD, multivessel CABG was associated with lower risks of death and coronary events compared with multivessel PCI.

Long-term survival and repeat coronary revascularization in dialysis patients after surgical and percutaneous coronary revascularization with drug-eluting and bare metal stents in the United States

BACKGROUND

Few published data describe long-term survival of dialysis patients undergoing surgical versus percutaneous coronary revascularization in the era of drug-eluting stents (DES).

METHODS AND RESULTS

Using United States Renal Data System data, we identified 23 033 dialysis patients who underwent coronary revascularization (6178 coronary artery bypass grafting, 5011 bare metal stents, 11 844 DES) from 2004 to 2009. Revascularization procedures decreased from 4347 in 2004 to 3344 in 2009. DES use decreased by 41% and bare metal stent use increased by 85% from 2006 to 2007. Long-term survival was estimated by the Kaplan-Meier method, and independent predictors of mortality were examined in a comorbidity-adjusted Cox model. In-hospital mortality for coronary artery bypass grafting patients was 8.2%; all-cause survival at 1, 2, and 5 years was 70%, 57%, and 28%, respectively. In-hospital mortality for DES patients was 2.7%; 1-, 2-, and 5-year survival was 71%, 53%, and 24%, respectively. Independent predictors of mortality were similar in both cohorts: age >65 years, white race, dialysis duration, peritoneal dialysis, and congestive heart failure, but not diabetes mellitus. Survival was significantly higher for coronary artery bypass grafting patients who received internal mammary grafts (hazard ratio, 0.83; P<0.0001). The probability of repeat revascularization accounting for the competing risk of death was 18% with bare metal stents, 19% with DES, and 6% with coronary artery bypass grafting at 1 year.

CONCLUSIONS

Among dialysis patients undergoing coronary revascularization, in-hospital mortality was higher after coronary artery bypass grafting, but long-term survival was superior with internal mammary grafts. In-hospital mortality was lower for DES patients, but the probability of repeat revascularization was higher and comparable to that in patients receiving a bare metal stent. Revascularization decisions for dialysis patients should be individualized.

Management of coronary artery disease in end-stage renal disease

Despite a substantial number of patients with end-stage renal disease who have coronary artery disease, the comparative effectiveness of revascularization procedures such as coronary artery bypass grafting and percutaneous coronary intervention remain unclear. Innovations in the field of coronary artery revascularization and concomitant changes in the standard of practice have improved outcomes in general. However, meaningful clinical decision-making remains difficult because it requires clinicians to extrapolate evidence derived from studies in the general population to patients with kidney disease for whom there is limited information from intervention trials. In non-randomized studies, this high-risk population for cardiovascular morbidity and mortality appear to derive substantial benefits from coronary revascularization. However, specific treatment decisions are often made based upon individual circumstances and contexts that are not well captured in these studies. This article reviews the available evidence, and its limitations, for deciding between various revascularization strategies for patients with end-stage renal disease. Several considerations that arise while making such decisions are discussed.

Presurgical serum cystatin C and risk of acute kidney injury after cardiac surgery

BACKGROUND

Acute kidney injury (AKI) after cardiac surgery is associated with poor outcomes, but is challenging to predict from information available before surgery.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

The TRIBE-AKI (Translational Research Investigating Biomarker Endpoints in Acute Kidney Injury) Consortium enrolled 1,147 adults undergoing cardiac surgery at 6 hospitals from 2007-2009; participants were selected for high AKI risk.

PREDICTORS

Presurgical values for cystatin C, creatinine, and creatinine-based estimated glomerular filtration rate (eGFR) were categorized into quintiles and grouped as "best" (quintiles 1-2), "intermediate" (quintiles 3-4), and "worst" (quintile 5) kidney function.

OUTCOMES

The primary outcome was AKI Network (AKIN) stage 1 or higher; ≥0.3 mg/dL or 50% increase in creatinine level.

MEASUREMENTS

Analyses were adjusted for characteristics used clinically for presurgical risk stratification.

RESULTS

Average age was 71 ± 10 years (mean ± standard deviation); serum creatinine, 1.1 ± 0.3 mg/dL; eGFR-Cr, 74 ± 9 mL/min/1.73 m(2); and cystatin C, 0.9 ± 0.3 mg/L. 407 (36%) participants developed AKI during hospitalization. Adjusted odds ratios for intermediate and worst kidney function by cystatin C were 1.9 (95% CI, 1.4-2.7) and 4.8 (95% CI, 2.9-7.7) compared with 1.2 (95% CI, 0.9-1.7) and 1.8 (95% CI, 1.2-2.6) for creatinine and 1.0 (95% CI, 0.7-1.4) and 1.7 (95% CI, 1.1-2.3) for eGFR-Cr categories, respectively. After adjustment for clinical predictors, the C statistic to predict AKI was 0.70 without kidney markers, 0.69 with creatinine, and 0.72 with cystatin C. Cystatin C also substantially improved AKI risk classification compared with creatinine, based on a net reclassification index of 0.21 (P < 0.001).

LIMITATIONS

The ability of these kidney biomarkers to predict risk of dialysis-requiring AKI or death could not be assessed reliably in our study because of a small number of patients with either outcome.

CONCLUSIONS

Presurgical cystatin C is better than creatinine or creatinine-based eGFR at forecasting the risk of AKI after cardiac surgery.

Cardiorenal Syndrome: The Clinical Cardiologists' Perspective

The term cardiorenal syndrome has evolved over the years. The understanding of the interactions between these two organ systems has led to better recognition and treatment strategies. As cardiovascular mortality is high in individuals with renal dysfunction, it is imperative to understand the pathophysiology behind the disease process. This knowledge may better serve these patients with this syndrome and improve their outcomes. In this review, we examine the key issues of the cardiorenal syndrome from a cardiologist's perspective.