Increased Aortic Stiffness Is Associated With Higher Rates of Stroke, Gastrointestinal Bleeding and Pump Thrombosis in Patients With a Continuous Flow Left Ventricular Assist Device.

BACKGROUND: In the general population, increased aortic stiffness is associated with an increased risk of cardiovascular events. Previous studies have demonstrated an increase in aortic stiffness in patients with a continuous flow left ventricular assist device (CF-LVAD). However, the association between aortic stiffness and common adverse events is unknown. METHODS AND RESULTS: Forty patients with a HeartMate II (HMII) (51 $ 11 years; 20% female; 25% ischemic) implanted between January 2011 and September 2017 were included. Two-dimensional transthoracic echocardiograms of the ascending aorta, obtained before HMII placement and early after heart transplant, were analyzed to calculate the aortic stiffness index (AO-SI). The study cohort was divided into patients who had an increased vs decreased AO-SI after LVAD support. A composite outcome of gastrointestinal bleeding, stroke, and pump thrombosis was defined as the primary end point and compared between the groups. While median AO-SI increased significantly after HMII support (AO-SI 4.4-6.5, P = .012), 16 patients had a lower AO-SI. Patients with increased (n = 24) AO-SI had a significantly higher rate of the composite end point (58% vs 12%, odds ratio 9.8, P < .01). Similarly, those with increased AO-SI tended to be on LVAD support for a longer duration, had higher LVAD speed and reduced use of angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers. CONCLUSIONS: Increased aortic stiffness in patients with a HMII is associated with a significantly higher rates of adverse events. Further studies are warranted to determine the causality between aortic stiffness and adverse events, as well as the effect of neurohormonal modulation on the conduit vasculature in patients with a CF-LVAD.

Carotid artery structure and hemodynamics and their association with adverse vascular events in left ventricular assist device patients.

Left ventricular assist devices (LVADs) are associated with major vascular complications including stroke and gastrointestinal bleeding (GIB). These adverse vascular events may be the result of widespread vascular dysfunction resulting from pre-LVAD abnormalities or continuous flow during LVAD therapy. We hypothesized that pre-existing large artery atherosclerosis and/or abnormal blood flow as measured in carotid arteries using ultrasonography are associated with a post-implantation composite adverse outcome including stroke, GIB, or death. We retrospectively studied 141 adult HeartMate II patients who had carotid ultrasound duplex exams performed before and/or after LVAD surgery. Structural parameters examined included plaque burden and stenosis. Hemodynamic parameters included peak-systolic, end-diastolic, and mean velocity as well as pulsatility index. We examined the association of these measures with the composite outcome as well as individual subcomponents such as stroke. After adjusting for established risk factors, the composite adverse outcome was associated with pre-operative moderate-to-severe carotid plaque (OR 5.08, 95% CI 1.67-15.52) as well as pre-operative internal carotid artery stenosis (OR 9.02, 95% CI 1.06-76.56). In contrast, altered hemodynamics during LVAD support were not associated with the composite outcome. Our findings suggest that pre-existing atherosclerosis possibly in combination with LVAD hemodynamics may be an important contributor to adverse vascular events during mechanical support. This encourages greater awareness of carotid morphology pre-operatively and further study of the interaction between hemodynamics, pulsatility, and structural arterial disease during LVAD support.

Gut microbial diversity, inflammation, and oxidative stress are associated with tacrolimus dosing requirements early after heart transplantation.

INTRODUCTION: Effective tacrolimus (TAC) dosing is hampered by complex pharmacokinetics and significant patient variability. The gut microbiome, a key mediator of endotoxemia, inflammation and oxidative stress in advanced heart failure (HF) patients, is a possible contributor to interindividual variations in drug efficacy. The effect of alterations in the gut microbiome on TAC dosing requirements after heart transplant (HT) has not been explored. METHODS: We enrolled 24 patients (mean age = 55.8 ±2.3 years) within 3 months post-HT. Biomarkers of endotoxemia ((lipopolysaccharide (LPS)), inflammation (tumor necrosis factor-α (TNF-α)) and oxidative stress (8,12-iso-Isoprostane F-2alpha-VI) were measured in 16 blood samples. 22 stool samples were analyzed using 16S rRNA sequencing. TAC dose and serum trough level were measured at the time of stool and blood collection. TAC doses were reported in mg/kg/day and as level-to-dose (L/D) ratio, and categorized as ≤ vs. > median. RESULTS: The median TAC dose was 0.1 mg/kg/day and L/D ratio was 100.01. Above the median daily weight-based TAC dose was associated with higher gut microbial alpha diversity (p = 0.03); similarly, TNF-α and 8,12-iso-Isoprostane F-2alpha-VI levels were lower and LPS levels were higher in the above median TAC group, although these findings were only marginally statistically significant and dependent on BMI adjustment. We observed n = 37 taxa to be significantly enriched among patients with > median TAC dose (all FDR<0.05), several of which are potential short-chain fatty acid producers with anti-inflammatory properties, including taxa from the family Subdoligranulum. CONCLUSIONS: Our pilot study observed gut microbial alpha diversity to be increased while inflammation and oxidative stress were reduced among patients requiring higher TAC doses early after HT.

Cystatin C- Versus Creatinine-Based Assessment of Renal Function and Prediction of Early Outcomes Among Patients With a Left Ventricular Assist Device.

BACKGROUND: Estimated glomerular filtration rate (eGFR) based on serum creatinine (sCr) improves early after left ventricular assist device (LVAD) implantation but subsequently declines. Although sCr is a commonly accepted clinical standard, cystatin C (CysC) has shown superiority in assessment of renal function in disease states characterized by muscle wasting. Among patients with an LVAD, we aimed to (1) longitudinally compare CysC-eGFR and sCr-eGFR, (2) assess their predictive value for early postoperative outcomes, and (3) investigate mechanisms which might explain potential discrepancies. METHODS: A prospective cohort (n=116) with CysC and sCr concurrently measured at serial time points, and a retrospective cohort (n=91) with chest computed tomography performed within 40 days post-LVAD were studied. In the prospective cohort, the primary end point was a composite of in-hospital mortality, renal replacement therapy, or severe right ventricular failure. In the retrospective cohort, muscle mass was estimated using pectoralis muscle area indexed to body surface area (pectoralis muscle index). RESULTS: In the prospective cohort, sCr-eGFR significantly improved early post-LVAD and subsequently declined, whereas CysC-eGFR remained stable. CysC-eGFR but not sCr-eGFR predicted the primary end point: odds ratio per 5 mL/(min·1.73 m2) decrease 1.16 (1.02-1.31) versus 0.99 (0.94-1.05). In retrospective cohort, for every 5 days post-LVAD, a 6% decrease in pectoralis muscle index was observed (95% CI, 2%-9%, P=0.003). After adjusting for time on LVAD, for every 1 cm2/m2 decrease in pectoralis muscle index, there was a 4% decrease in 30-day post-LVAD sCr (95% CI, 1%-6%, P=0.004). CONCLUSIONS: Initial improvement in sCr-eGFR is likely due to muscle wasting following LVAD surgery. CysC may improve assessment of renal function and prediction of early postoperative outcomes in patients with an LVAD.

Gut microbiota, endotoxemia, inflammation, and oxidative stress in patients with heart failure, left ventricular assist device, and transplant.

BACKGROUND: Gut microbial imbalance may contribute to endotoxemia, inflammation, and oxidative stress in heart failure (HF). Changes occurring in the intestinal microbiota and inflammatory/oxidative milieu during HF progression and following left ventricular assist device (LVAD) or heart transplantation (HT) are unknown. We aimed to investigate variation in gut microbiota and circulating biomarkers of endotoxemia, inflammation, and oxidative stress in patients with HF (New York Heart Association, Class I-IV), LVAD, and HT. METHODS: We enrolled 452 patients. Biomarkers of endotoxemia (lipopolysaccharide and soluble [sCD14]), inflammation (C-reactive protein, interleukin-6, tumor necrosis factor-α, and endothelin-1 adiponectin), and oxidative stress (isoprostane) were measured in 644 blood samples. A total of 304 stool samples were analyzed using 16S rRNA sequencing. RESULTS: Gut microbial community measures of alpha diversity were progressively lower across worsening HF class and were similarly reduced in patients with LVAD and HT (p < 0.05). Inflammation and oxidative stress were elevated in patients with Class IV HF vs all other groups (all p < 0.05). Lipopolysaccharide was elevated in patients with Class IV HF (vs Class I-III) as well as in patients with LVAD and HT (p < 0.05). sCD14 was elevated in patients with Class IV HF and LVAD (vs Class I-III, p < 0.05) but not in patients with HT. CONCLUSIONS: Reduced gut microbial diversity and increased endotoxemia, inflammation, and oxidative stress are present in patients with Class IV HF. Inflammation and oxidative stress are lower among patients with LVAD and HT relative to patients with Class IV HF, whereas reduced gut diversity and endotoxemia persist in LVAD and HT.

Comparison of the Hemodynamic Response to Intra-Aortic Balloon Counterpulsation in Patients With Cardiogenic Shock Resulting from Acute Myocardial Infarction Versus Acute Decompensated Heart Failure.

The intra-aortic balloon pump (IABP) neither benefits nor harms patients with acute myocardial infarction (AMI) with cardiogenic shock (CS) but may stabilize those with chronic heart failure who decompensate into CS. We sought to compare its hemodynamic effects in these 2 populations. We performed a retrospective analysis of the hemodynamic effects of IABP for AMI or acute decompensated heart failure (ADHF) patients with hemodynamic evidence of CS. The primary outcome was cardiac output (CO) change following insertion. In total, 205 patients were treated for CS resulting from AMI (73; 35.6%) or ADHF (132; 64.4%). At baseline, both cohorts had significant hemodynamic compromise with mean arterial pressure 75.6 ± 12.3 mm Hg, CO 3.02 ± 0.84 L/min, and cardiac power index 0.26 ± 0.06 W/m2; these parameters were nearly identical between groups though ADHF-CS patients had a higher pre-IABP mean pulmonary artery (PA) pressure than AMI-CS patients. After IABP insertion, ADHF-CS patients had moderate CO augmentation whereas AMI-CS experienced almost no improvement (0.58 ± 0.79 L/min vs 0.12 ± 1.00 L/min; p = 0.0009). Intracardiac filling pressures were reduced by similar amounts in both cohorts. Systemic vascular resistance was reduced in patients with ADHF-CS but not in those with AMI-CS. In conclusion, following IABP insertion, ADHF-CS patients experience roughly a 5-fold greater CO augmentation compared with AMI-CS patients. Pre-IABP PA pressure differences and differential systemic vascular resistance reduction may explain these results and shed light on recent evidence supporting IABP use in ADHF-CS and curbing it in AMI-CS.

Prognostic implications of serial outpatient blood pressure measurements in patients with an axial continuous-flow left ventricular assist device.

BACKGROUND: Elevated blood pressure (BP) has been linked to adverse events during left ventricular assist device support. In this study we investigated the association between outpatient BP and stroke or suspected pump thrombosis among HeartMate II (HMII) recipients. METHODS: We retrospectively studied 220 HMII patients. Serial outpatient BP measurements were averaged. Patients were categorized by: (1) mean arterial pressure (MAP), high (>90 mm Hg) vs intermediate (80 mm Hg ≤ MAP ≤ 90 mm Hg) vs low (<80 mm Hg); (2) systolic BP (SBP), high (≥101 mm Hg, median) vs low; and (3) pulse pressure (PP), high (≥22 mm Hg, median) vs low. To assess visit-to-visit BP variability, patients were divided in quartiles of standard deviation of MAP and SBP. The primary end-point was the composite of stroke or suspected pump thrombosis. RESULTS: The risk for the primary end-point was increased in the high MAP group (adjusted hazard ratio [HR] 2.75, 95% confidence interval [CI] 1.49 to 5.05, vs intermediate MAP; and 6.73, 1.9 to 23.9, vs low MAP). MAP had higher predictive value for the primary end-point compared with SBP (p = 0.05). Patients with high SBP had a higher rate of stroke (HR 2.8, 95% CI 1.09 to 7.17, vs low SBP). The combination of high SBP and low PP was associated with the highest risk for stroke. The lowest quartile of visit-to-visit MAP variability was associated with the highest risk for the primary end-point. CONCLUSIONS: Elevated outpatient BP is associated with increased risk for stroke or suspected pump thrombosis in HMII recipients. Reduced PP and low visit-to-visit BP variability may confer additional risk.