A Fully Magnetically Levitated Circulatory Pump for Advanced Heart Failure

BACKGROUND

Continuous-flow left ventricular assist systems increase the rate of survival among patients with advanced heart failure but are associated with the development of pump thrombosis. We investigated the effects of a new magnetically levitated centrifugal continuous-flow pump that was engineered to avert thrombosis.

METHODS

We randomly assigned patients with advanced heart failure to receive either the new centrifugal continuous-flow pump or a commercially available axial continuous-flow pump. Patients could be enrolled irrespective of the intended goal of pump support (bridge to transplantation or destination therapy). The primary end point was a composite of survival free of disabling stroke (with disabling stroke indicated by a modified Rankin score >3; scores range from 0 to 6, with higher scores indicating more severe disability) or survival free of reoperation to replace or remove the device at 6 months after implantation. The trial was powered for noninferiority testing of the primary end point (noninferiority margin, -10 percentage points).

RESULTS

Of 294 patients, 152 were assigned to the centrifugal-flow pump group and 142 to the axial-flow pump group. In the intention-to-treat population, the primary end point occurred in 131 patients (86.2%) in the centrifugal-flow pump group and in 109 (76.8%) in the axial-flow pump group (absolute difference, 9.4 percentage points; 95% lower confidence boundary, -2.1 [P<0.001 for noninferiority]; hazard ratio, 0.55; 95% confidence interval [CI], 0.32 to 0.95 [two-tailed P=0.04 for superiority]). There were no significant between-group differences in the rates of death or disabling stroke, but reoperation for pump malfunction was less frequent in the centrifugal-flow pump group than in the axial-flow pump group (1 [0.7%] vs. 11 [7.7%]; hazard ratio, 0.08; 95% CI, 0.01 to 0.60; P=0.002). Suspected or confirmed pump thrombosis occurred in no patients in the centrifugal-flow pump group and in 14 patients (10.1%) in the axial-flow pump group.

CONCLUSIONS

Among patients with advanced heart failure, implantation of a fully magnetically levitated centrifugal-flow pump was associated with better outcomes at 6 months than was implantation of an axial-flow pump, primarily because of the lower rate of reoperation for pump malfunction. (Funded by St. Jude Medical; MOMENTUM 3 ClinicalTrials.gov number, NCT02224755 .).

Amiodarone use in patients listed for heart transplant is associated with increased 1-year post-transplant mortality

BACKGROUND

Pre-transplant amiodarone use has been postulated as a risk factor for morbidity and mortality after orthotopic heart transplantation (OHT). We assessed pre-OHT amiodarone use and tested the hypothesis that it is associated with impaired post-OHT outcomes.

METHODS

We performed a retrospective cohort analysis of adult OHT recipients from the registry of the International Society for Heart and Lung Transplantation (ISHLT). All patients had been transplanted between 2005 and 2013 and were stratified by pre-OHT amiodarone use. We derived propensity scores using logistic regression with amiodarone use as the dependent variable, and assessed the associations between amiodarone use and outcomes with Kaplan-Meier analysis after matching patients 1:1 based on propensity score, and with Cox regression with adjustment for propensity score.

RESULTS

Of the 14,944 OHT patients in the study cohort, 32% (N = 4,752) received pre-OHT amiodarone. Amiodarone use was higher in recent years (29% in 2005 to 2007, 32% in 2008 to 2010, 35% in 2011 to 2013). Amiodarone-treated patients were older and more frequently had a history of sudden cardiac death (27% vs 13%) and pre-OHT mechanical circulatory support. Key donor characteristics and allograft ischemia times were similar between groups. In propensity-matched analyses, amiodarone-treated patients had higher rates of cardiac reoperation (15% vs 13%) and permanent pacemaker (5% vs 3%) after OHT and before discharge. Amiodarone-treated patients also had higher 1-year mortality (hazard ratio 1.15, 95% confidence interval 1.02 to 1.30), but the risks of early graft failure, retransplantation and rehospitalization were similar between groups.

CONCLUSIONS

Amiodarone use before OHT was independently associated with increased 1-year mortality. The need for amiodarone therapy should be carefully and continuously assessed in patients awaiting OHT.

Concomitant Thoracic Aortobifemoral Bypass With Left Ventricular Assist Device Implantation

Improved quality of life for patients after left ventricular assist device (LVAD) implantation can be greatly limited by peripheral vascular disease even if heart failure symptoms are resolved by LVAD support. We present a case of concomitant thoracic aortobifemoral bypass and LVAD implantation in a patient with ischemic cardiomyopathy, severe peripheral vascular disease, and multiple previous failed revascularization attempts. In this patient, we used the LVAD outflow to provide the inflow to the femoral artery bypass graft. This graft has remained patent at a 2-year follow-up, without claudication symptoms. Performing concomitant major vascular operations safely and successfully is feasible in patients with LVADs. Quality of life after ventricular assist device placement can be limited by vascular disease, but it can be markedly improved after vascular surgical intervention.

Usefulness of Palliative Care to Complement the Management of Patients on Left Ventricular Assist Devices

Within the last decade, advancements in left ventricular assist device therapy have allowed patients with end-stage heart failure (HF) to live longer and with better quality of life. Like other life-saving interventions, however, there remains the risk of complications including infections, bleeding episodes, and stroke. The candidate for left ventricular assist device therapy faces complex challenges going forward, both physical and psychological, many of which may benefit from the application of palliative care principles by trained specialists. Despite these advantages, palliative care remains underused in many advanced HF programs. Here, we describe the benefits of palliative care, barriers to use within HF, and specific applications to the integrated care of patients on mechanical circulatory support.

The Diagnostic Yield of Repeated Endoscopic Evaluation in Patients with Gastrointestinal Bleeding and Left Ventricular Assist Devices

INTRODUCTION

Left ventricular assist devices (LVADs) are increasingly common in patients with advanced heart failure. GI bleeding (GIB) occurs in 20-30 % of these patients and can arise anywhere in the GI tract. Given the high rates of GIB in this population, our aim was to determine the diagnostic yield of repeated endoscopic evaluation in these patients.

METHODS

We performed a retrospective review of all 257 patients who had LVADs placed between 2008 and 2013 at Duke University Hospital and identified all patients who underwent any endoscopic evaluation for GIB.

RESULTS

Of the 257 patients with LVADs placed, 78 (30 %) underwent at least one endoscopy for GIB. A source was identified in 36 % of cases, most commonly angioectasias (53.6 %). Treatment was performed in 67.9 % of patients and hemostasis was achieved in all. 64.1 % of the cohort underwent a second endoscopy for GIB. 42.9 % of these exams revealed a bleeding source. Endoscopic treatment was employed in 76.2 %. 38.5 % of the cohort underwent a third endoscopic exam for bleeding and a source was identified in 53.3 % with angioectasias remaining most common (56.3 %). By Fisher's exact and Chi-square testing, only the presence of a bleeding source (p = 0.0034) and use of hemostatic therapy (p = 0.0127) on the index examination were significantly associated with re-bleeding.

CONCLUSIONS

GIB is common in patients with LVADs. The diagnostic and therapeutic yield of endoscopy is remains high with repeated interventions. Despite these high yields, a large portion of the cohort requires repeated interventions for recurrent bleeding.

Prognostic Implications of Long-Chain Acylcarnitines in Heart Failure and Reversibility With Mechanical Circulatory Support

BACKGROUND

Heart failure (HF) is characterized by perturbations in energy homeostasis and metabolism. The reversibility and prognostic value of circulating markers associated with these changes remain unclear.

OBJECTIVES

This study sought to describe the metabolomic profiles of patients along the spectrum of systolic HF, determine their association with adverse outcomes in a clinical trial of HF, and evaluate whether identified metabolites change with treatment for end-stage systolic HF.

METHODS

To assess association of metabolites with clinical outcomes, we evaluated a population of 453 chronic systolic HF patients who had been randomized to exercise training versus usual care. To assess change in metabolites with mechanical circulatory support, 41 patients with end-stage HF who underwent left ventricular assist device (LVAD) placement were studied. Targeted, quantitative profiling of 60 metabolites using tandem flow injection mass spectrometry was performed on frozen plasma samples obtained prior to randomization, as well as prior to and ≥90 days post-placement in the LVAD group. Principal components analysis was used for data reduction.

RESULTS

Five principal components analysis-derived factors were significantly associated with peak Vo2 levels at baseline in fully adjusted models. Of these, factor 5 (composed of long-chain acylcarnitines) was associated with increased risk of all 3 pre-specified clinical trial outcomes: all-cause mortality/all-cause hospitalization, all cause-hospitalization, and cardiovascular death or cardiovascular hospitalization. Individual components of factor 5 were significantly higher in patients with end-stage HF prior to LVAD placement and decreased significantly post-implantation.

CONCLUSIONS

In chronic HF patients, circulating long-chain acylcarnitine metabolite levels were independently associated with adverse clinical outcomes and decreased after long-term mechanical circulatory support. These metabolites may serve as potential targets for new diagnostics or therapeutic interventions. (Exercise Training Program to Improve Clinical Outcomes in Individuals With Congestive Heart Failure; NCT00047437).

Two-Year Outcomes of Surgical Treatment of Moderate Ischemic Mitral Regurgitation

BACKGROUND

In a trial comparing coronary-artery bypass grafting (CABG) alone with CABG plus mitral-valve repair in patients with moderate ischemic mitral regurgitation, we found no significant difference in the left ventricular end-systolic volume index (LVESVI) or survival after 1 year. Concomitant mitral-valve repair was associated with a reduced prevalence of moderate or severe mitral regurgitation, but patients had more adverse events. We now report 2-year outcomes.

METHODS

We randomly assigned 301 patients to undergo either CABG alone or the combined procedure. Patients were followed for 2 years for clinical and echocardiographic outcomes.

RESULTS

At 2 years, the mean (±SD) LVESVI was 41.2±20.0 ml per square meter of body-surface area in the CABG-alone group and 43.2±20.6 ml per square meter in the combined-procedure group (mean improvement over baseline, -14.1 ml per square meter and -14.6 ml per square meter, respectively). The rate of death was 10.6% in the CABG-alone group and 10.0% in the combined-procedure group (hazard ratio in the combined-procedure group, 0.90; 95% confidence interval, 0.45 to 1.83; P=0.78). There was no significant between-group difference in the rank-based assessment of the LVESVI (including death) at 2 years (z score, 0.38; P=0.71). The 2-year rate of moderate or severe residual mitral regurgitation was higher in the CABG-alone group than in the combined-procedure group (32.3% vs. 11.2%, P<0.001). Overall rates of hospital readmission and serious adverse events were similar in the two groups, but neurologic events and supraventricular arrhythmias remained more frequent in the combined-procedure group.

CONCLUSIONS

In patients with moderate ischemic mitral regurgitation undergoing CABG, the addition of mitral-valve repair did not lead to significant differences in left ventricular reverse remodeling at 2 years. Mitral-valve repair provided a more durable correction of mitral regurgitation but did not significantly improve survival or reduce overall adverse events or readmissions and was associated with an early hazard of increased neurologic events and supraventricular arrhythmias. (Funded by the National Institutes of Health and Canadian Institutes of Health Research; ClinicalTrials.gov number, NCT00806988.).

Trends and outcomes of patients with adult congenital heart disease and pulmonary hypertension listed for orthotopic heart transplantation in the United States

BACKGROUND

Heart transplantation is increasing in patients with adult congenital heart disease (ACHD). In this population, the association of pulmonary hypertension (PH) with post-transplant outcomes is not well-defined.

METHODS

Using data from the United Network for Organ Sharing database (1987 to 2014), we identified ACHD patients listed for heart transplantation, and examined survival between those with and without PH (pre-transplant PH defined as transpulmonary pressure gradient >12 mm Hg).

RESULTS

Among 983 ACHD patients, 216 (22%) had PH. At time of listing, PH patients had a transpulmonary pressure gradient of 17.0 mm Hg vs 6.0 mm Hg (p < 0.01) in the no-PH group. Although left ventricular assist device (LVAD) use was infrequent, 3.1% of PH patients were treated with an LVAD versus 6.8% of the no-PH patients. Days from listing to transplant, days from listing to death on the waitlist and length of post-transplant hospitalization were not significantly different between the PH and no-PH groups. However, PH was associated with higher waitlist mortality (HR 1.73, CI 1.25 to 2.41). Pre-transplant PH was not associated with post-transplant mortality at 30 days (HR 0.51, CI 0.23 to 1.13), 1 year (HR 0.68, 95% CI 0.40 to 1.18) or 5 years (HR 0.84, 95% CI 0.55 to 1.29).

CONCLUSIONS

PH is common among ACHD patients listed for transplant and is associated with increased waitlist mortality. Conversely, PH was not associated with worse survival after transplant. Bridge-to-transplant LVAD therapy was uncommon in this ACHD population.

Resection of Carcinoid Tumor Metastatic to the Right Ventricle and Tricuspid Valve

Carcinoid tumors rarely metastasize to the heart, and previous reports involved the myocardium only. We present a case of carcinoid tumor metastatic to the right ventricle (RV) and tricuspid valve. Preoperative cardiac magnetic resonance imaging (CMR) showed the tumor arising from the right ventricular free wall and involving the tricuspid valve apparatus. The tumor was resected through a right atriotomy and required tricuspid valve replacement.

Getting to a Man's Heart through His Colon

A 69-year-old man presented with a progressively enlarging pulsatile mass in the left side of his chest. Because of a history of an ischemic cardiomyopathy, he had been randomized in 2003 to undergo coronary artery bypass grafting with a Dor procedure, as part of the Surgical Treatment for Ischemic Heart Failure (STICH) trial. Our patient's imaging studies, including a thoracic computed tomogram and transthoracic echocardiogram, were now of concern for left ventricular pseudoaneurysm. He was taken immediately for surgical exploration. Purulent material, with empyema, extended from the anterior chest wall through the chest cavity into the mediastinum, with communication into the pericardial space. Notably, there was no compromise of the left ventricular cavity, and there was no pseudoaneurysm. The chest was copiously irrigated before closure. The epicardial patch placed 10 years earlier in the STICH trial was not thought to be the nidus of the abscess and was therefore not removed. Three months later, the patient presented again, this time with hemorrhagic shock and bleeding from his left anterior thoracotomy site, which we then re-entered. He was found to have a left ventricular pseudoaneurysm with disruption of the ventricular apex. The epicardial felt-and-Dacron patch, placed 10 years previously during his Dor procedure, was found to be infected with Clostridium difficile and was removed. The left ventricular apex was repaired. Whereas C. difficile bacteremia is rare, the seeding of prosthetic cardiac material with delayed presentation, as in this case, is extraordinarily uncommon.

Hemodynamic Predictors of Heart Failure Morbidity and Mortality: Fluid or Flow?

BACKGROUND

Patients with advanced heart failure may continue for prolonged times with persistent hemodynamic abnormalities; intermediate- and long-term outcomes of these patients are unknown.

METHODS AND RESULTS

We used ESCAPE (Evaluation Study of Congestive Heart Failure and Pulmonary Artery Catheterization Effectiveness) trial data to examine characteristics and outcomes of patients with invasive hemodynamic monitoring during an acute heart failure hospitalization. Patients were stratified by final measurement of cardiac index (CI; L/min/m2) and pulmonary capillary wedge pressure (PCWP; mmHg) before catheter removal. The study groups were CI ≥ 2/PCWP < 20 (n = 74), CI ≥ 2/PCWP ≥ 20 (n = 37), CI < 2/PCWP < 20 (n = 23), and CI < 2/PCWP ≥ 20 (n = 17). Final CI was not associated with the combined risk of death, cardiovascular hospitalization, and transplantation (hazard ratio [HR]1.03, 95% confidence interval 0.96-1.11 per 0.2 L/min/m2 decrease, P = .39), but final PCWP ≥ 20 mmHg was associated with increased risk of these events (HR 2.03, 95% confidence interval 1.31-3.15, P < .01), as was higher final right atrial pressure (HR 1.09, 95% confidence interval 1.06-1.12 per mmHg increase, P < .01).

CONCLUSION

Final PCWP and final right atrial pressure were stronger predictors of postdischarge outcomes than CI in patients with advanced heart failure. The ability to lower filling pressures appears to be more prognostically important than improving CI in the management of patients with advanced heart failure. ClinicalTrials.govIdentifier: NCT00000619.

Gene signatures of postoperative atrial fibrillation in atrial tissue after coronary artery bypass grafting surgery in patients receiving β-blockers

Atrial tissue gene expression profiling may help to determine how differentially expressed genes in the human atrium before cardiopulmonary bypass (CPB) are related to subsequent biologic pathway activation patterns, and whether specific expression profiles are associated with an increased risk for postoperative atrial fibrillation (AF) or altered response to β-blocker (BB) therapy after coronary artery bypass grafting (CABG) surgery. Right atrial appendage (RAA) samples were collected from 45 patients who were receiving perioperative BB treatment, and underwent CABG surgery. The isolated RNA samples were used for microarray gene expression analysis, to identify probes that were expressed differently in patients with and without postoperative AF. Gene expression analysis was performed to identify probes that were expressed differently in patients with and without postoperative AF. Gene set enrichment analysis (GSEA) was performed to determine how sets of genes might be systematically altered in patients with postoperative AF. Of the 45 patients studied, genomic DNA from 42 patients was used for target sequencing of 66 candidate genes potentially associated with AF, and 2,144 single-nucleotide polymorphisms (SNPs) were identified. We then performed expression quantitative trait loci (eQTL) analysis to determine the correlation between SNPs identified in the genotyped patients, and RAA expression. Probes that met a false discovery rate<0.25 were selected for eQTL analysis. Of the 17,678 gene expression probes analyzed, 2 probes met our prespecified significance threshold of false discovery rate<0.25. The most significant probe corresponded to vesicular overexpressed in cancer - prosurvival protein 1 gene (VOPP1; 1.83 fold change; P=3.47×10(-7)), and was up-regulated in patients with postoperative AF, whereas the second most significant probe, which corresponded to the LOC389286 gene (0.49 fold change; P=1.54×10(-5)), was down-regulated in patients with postoperative AF. GSEA highlighted the role of VOPP1 in pathways with biologic relevance to myocardial homeostasis, and oxidative stress and redox modulation. Candidate gene eQTL showed a trans-acting association between variants of G protein-coupled receptor kinase 5 gene, previously linked to altered BB response, and high expression of VOPP1. In patients undergoing CABG surgery, RAA gene expression profiling, and pathway and eQTL analysis suggested that VOPP1 plays a novel etiological role in postoperative AF despite perioperative BB therapy.

Cardiac transplantation for older patients: Characteristics and outcomes in the septuagenarian population

BACKGROUND

With increasing age of patients with heart failure, it is important to understand the potential role for orthotopic heart transplant (OHT) in elderly patients. We examined recipient and donor characteristics and long-term outcomes of older recipients of OHT in the United States.

METHODS

Using the United Network for Organ Sharing database, we identified OHT recipients from the years 1987-2014 and stratified them by age 18-59 years old, 60-69 years old, and ≥70 years old. We compared baseline characteristics of recipients and donors and assessed outcomes across groups.

RESULTS

During this period, 50,432 patients underwent OHT; 71.8% (n = 36,190) were 18-59 years old, 26.8% (n = 13,527) were 60-69 years old, and 1.4% (n = 715) were ≥70 years old. Comparing the ≥70 years old group and 60-69 years old group, older patients had higher rates of ischemic etiology (53.6% vs 44.9%) and baseline renal dysfunction (61.4% vs 56.4%) and at the time of OHT were less likely to be currently hospitalized (45.0% vs 50.9%) or supported with left ventricular assist device therapy (21.0% vs 28.3%). Older recipients received organs from older donors (median age 36 years old vs 30 years old) who were more likely to have diabetes and substance use. After OHT, the median length of stay was similar between groups. At 1 year, of patients alive, patients ≥70 years old had fewer rejection episodes (17.8%) compared with patients 60-69 years old (29.5%). The 5-year mortality was 26.9% for recipients 18-59 years old, 29.3% for recipients 60-69 years old, and 30.8% for recipients ≥70 years old.

CONCLUSIONS

Despite advanced age and less ideal donors, OHT recipients in their 70s had similar outcomes to recipients in their 60s. Selected older patients should not routinely be excluded from consideration for OHT.

Elevated Cardiac Troponin I in Preservation Solution Is Associated With Primary Graft Dysfunction

BACKGROUND

Although primary graft dysfunction (PGD) is a leading cause of mortality and morbidity early post-heart transplant, relatively little is known regarding mechanisms involved in PGD development.

METHODS AND RESULTS

We examined the relationship between cardiac troponin I (cTnI) concentrations in the preservation solution from 43 heart transplant procedures and the development of PGD. Donor hearts were flushed with cold preservation solution (University of Wisconsin [UW] or Custodiol) and stored in the same solution. cTnI concentrations were measured utilizing the i-STAT System and normalized to left ventricular mass. Recipient medical records were reviewed to determine PGD according to the 2014 ISHLT consensus conference. Nineteen patients developed PGD following cardiac transplantation. For both UW and Custodiol, normalized cTnI levels were significantly increased (P = .031 and .034, respectively) for those cases that developed PGD versus no PGD. cTnI levels correlated with duration of ischemic time in the UW group, but not for the Custodiol group. Donor age and donor cTnI (obtained prior to organ procurement) did not correlate with preservation cTnI levels in either UW or Custodiol.

CONCLUSIONS

Increased preservation solution cTnI is associated with the development of PGD suggesting preservation injury may be a dominant mechanism for the development of PGD.

Genome-wide association study of new-onset atrial fibrillation after coronary artery bypass grafting surgery

BACKGROUND

Postoperative atrial fibrillation (AF) is a potentially life-threatening complication after coronary artery bypass graft (CABG) surgery. Genetic predisposition may predict risk for developing postoperative AF.

METHODS

Study subjects underwent CABG surgery with cardiopulmonary bypass at Duke University Medical Center. In a discovery cohort of 877 individuals from the Perioperative Genetics and Safety Outcomes Study, we performed a genome-wide association study using a logistic regression model with a covariate adjustment for AF risk index. Single-nucleotide polymorphisms (SNPs) that met a P < 5 × 10(-5) were further tested using a replication dataset of 304 individuals from the CATHeterization GENetics biorepository, followed by meta-analysis. Potential pathways related to postoperative AF were identified through gene enrichment analysis using the top genome-wide association study SNPs (P < 10(-4)).

RESULTS

Nineteen SNPs met the a priori defined discovery threshold for replication, but only 3 met nominal significance (P < .05) in the CATHeterization GENetics group, with only one-rs10504554, in the intronic region in lymphocyte antigen 96 (LY96)-showing the same direction of the effect for postoperative AF (odds ratio [OR] 0.48, 95% CI 0.34-0.68, P = 2.9 × 10(-5) vs OR 0.55, 95% CI 0.31-0.99, P = .046) and strong overall association by meta-analysis (meta-P = 4.0 × 10(-6)). Gene enrichment analysis highlighted the role of LY96 in pathways of biologic relevance to activation and modulation of innate immune responses. Our analysis also showed potential association between LY96 and nuclear factor κ-B interaction and postoperative AF through their relevance to inflammatory signaling pathways.

CONCLUSIONS

In patients undergoing CABG surgery, we found genetic polymorphisms in LY96 associated with decreased risk of postoperative AF.

RNA-Mediated Reprogramming of Primary Adult Human Dermal Fibroblasts into c-kit(+) Cardiac Progenitor Cells

Cardiovascular disease is the leading cause of death in the United States. Heart failure is a common, costly, and potentially fatal condition that is inadequately managed by pharmaceuticals. Cardiac repair therapies are promising alternative options. A potential cardiac repair therapy involves reprogramming human fibroblasts toward an induced cardiac progenitor-like state. We developed a clinically useful and safer reprogramming method by nonintegrative delivery of a cocktail of cardiac transcription factor-encoding mRNAs into autologous human dermal fibroblasts obtained from skin biopsies. Using this method, adult and neonatal dermal fibroblasts were reprogrammed into cardiac progenitor cells (CPCs) that expressed c-kit, Isl-1, and Nkx2.5. Furthermore, these reprogrammed CPCs differentiated into cardiomyocytes (CMs) in vitro as judged by increased expression of cardiac troponin T, α-sarcomeric actinin, RyR2, and SERCA2 and displayed enhanced caffeine-sensitive calcium release. The ability to reprogram patient-derived dermal fibroblasts into c-kit(+) CPCs and differentiate them into functional CMs provides clinicians with a potential new source of CPCs for cardiac repair from a renewable source and an alternative therapy in the treatment of heart failure.

Genome-wide association study of acute kidney injury after coronary bypass graft surgery identifies susceptibility loci

Acute kidney injury (AKI) is a common, serious complication of cardiac surgery. Since prior studies have supported a genetic basis for postoperative AKI, we conducted a genome-wide association study (GWAS) for AKI following coronary bypass graft (CABG) surgery. The discovery dataset consisted of 873 non-emergent CABG surgery patients with cardiopulmonary bypass (PEGASUS), while a replication dataset had 380 cardiac surgical patients (CATHGEN). Single nucleotide polymorphism (SNP) data were based on Illumina Human610-Quad (PEGASUS) and OMNI1-Quad (CATHGEN) BeadChips. We used linear regression with adjustment for a clinical AKI risk score to test SNP associations with the postoperative peak rise relative to preoperative serum creatinine concentration as a quantitative AKI trait. Nine SNPs meeting significance in the discovery set were detected. The rs13317787 in GRM7|LMCD1-AS1 intergenic region (3p21.6) and rs10262995 in BBS9 (7p14.3) were replicated with significance in the CATHGEN data set and exhibited significantly strong overall association following meta-analysis. Additional fine-mapping using imputed SNPs across these two regions and meta-analysis found genome wide significance at the GRM7|LMCD1-AS1 locus and a significantly strong association at BBS9. Thus, through an unbiased GWAS approach, we found two new loci associated with post-CABG AKI providing new insights into the pathogenesis of perioperative AKI.