Effects of continuous-flow left ventricular assist devices on cerebral hemodynamics

Continuous-flow left ventricular assist devices (LVADs) reduce peak systolic flow, increase diastolic flow, and eliminate pulsatility of circulation. Altered blood flow may lead to a change in end-organ perfusion. Analysis of the flow dynamics of the arteries of end organs, such as the brain, may indicate whether an organ is perfused sufficiently. The aim of this study is to evaluate and identify the flow pattern changes of carotid (CA) and middle cerebral arteries (MCA) in LVAD patients and to compare with heart failure patients and healthy volunteers. Eighty-nine individuals were included in this cross-sectional study. Participants were divided into three groups: LVAD patients (n = 31), heart failure patients (n = 26), and healthy volunteers (n = 27). Carotid and transcranial Doppler ultrasonography were performed for all study groups for peak systolic velocity (PSV), end-diastolic velocity (EDV), pulsatility (PI), and resistive (RI) indices of CA and MCA. Flow dynamics were compared between the groups. Doppler ultrasonographic data were analyzed at a median 12 (3-47) months after LVAD implantation. CA-PSV was lower in LVAD group compared with the other two groups (P < .001), MCA-PSV of LVAD and heart failure groups were similar and lower than healthy volunteers (P < .05). The highest values for CA-EDV were found in the LVAD group (P < .05). MCA-EDV values were found to be lowest in heart failure group (P < .05). For PI and RI, in all CA and MCA, the LVAD group had lower indices compared with the other two groups (P < .001). In addition, MCA flow analysis in patients with LVADs was identified for the first time with this study.     

Mitral valve repair for severe mitral valve regurgitation during left ventricular assist device implantation

Background

The management of severe mitral regurgitation (MR) at the time of left ventricular assist device (LVAD) implantation is controversial. We adopted an approach of systematic repair of severe MR at the time of LVAD implantation and report our experience.

Prediction of acute kidney injury after left ventricular assist device implantation: Evaluation of clinical risk scores

Acute kidney injury (AKI) is frequent in patients scheduled for implantation of a left ventricular assist device (LVAD) and associated with increased mortality. Although several risk models for the prediction of postoperative renal replacement therapy (RRT) have been developed for cardiothoracic patients, none of these scoring systems have been validated in LVAD patients. A retrospective, single center analysis of all patients undergoing LVAD implantation between September 2013 and July 2016 was performed. Primary outcome was AKI requiring RRT within 14 days after surgery. The predictive capacity of the Cleveland Clinic Score (CCS), the Society of Thoracic Surgeons Score (STS), and the Simplified Renal Index Score (SRI) were evaluated. 76 patients underwent LVAD implantation, 19 patients were excluded due to preoperative RRT. RRT was associated with a prolonged ventilation time, length of stay on the ICU and 180 day mortality (14(60.9%) vs 6(17.6%), P < .01). Whereas the Thakar Score (7.43 ± 1.75 vs 6.44 ± 1.44, P = .02) and the Mehta Score (28.12 ± 15.08 vs 21.53 ± 5.43, P = .02) were significantly higher in patients with RRT than in those without RRT, the SRI did not differ between these groups (3.96 ± 1.15 vs 3.44 ± 1.05, P = .08). Using ROC analyses, CCS, STS, and SRI showed moderate predictive capacity for RRT with an AUC of 0.661 ± 0.073 (P = .040), 0.637 ± 0.079 (P = .792), and 0.618 ± 0.075 (P = .764), respectively, with comparable accuracy in the Delong test. Using univariate logistic regression analysis, only the De Ritis Ratio (OR 2.67, P = .034) and MELD (OR 1.11, P = .028) were identified as predictors of postoperative RRT. Risk scores which are predictive in general cardiac surgery cannot predict RRT in patients after LVAD implantation. Therefore, it seems to be necessary to develop a specific risk score for this patient population.     

Impact of Residual Mitral Regurgitation on Right Ventricular Systolic Function After Left Ventricular Assist Device Implantation

Significant mitral regurgitation (MR) is thought to decrease after left ventricular assist device (LVAD) implantation, and therefore repair of mitral valve is not indicated in current practice. However, residual moderate and severe MR leads to pulmonary artery pressure increase, thereby resulting in right ventricular (RV) dysfunction during follow‐up. We examined the impact of residual MR on systolic function of the right ventricle by echocardiography after LVAD implantation. This study included 90 patients (mean age: 51.7 ± 10.9 years, 14.4% female) who underwent LVAD implantation (HeartMate II = 21, HeartWare = 69) in a single center between December 2010 and June 2014. Echocardiograms obtained at 3–6 months and over after implantation were analyzed retrospectively. RV systolic function was graded as normal, mild, moderate, and severely depressed. MR (≥moderate) was observed in 43 and 44% of patients at early and late period, respectively. Systolic function of the RV was severely depressed in 16 and 9% of all patients. Initial analysis (mean duration of support 174.3 ± 42.5 days) showed a statistically significant correlation between less MR and improved systolic function of RV (P = 0.01). Secondary echocardiographic analysis (following a mean duration of support of 435.1 ± 203 days) was also statistically significant for MR degree and RV systolic dysfunction (P = 0.008). Residual MR after LVAD implantation may cause deterioration of RV systolic function and cause right‐sided heart failure symptoms. Repair of severe MR, in selected patients such as those with severe pulmonary hypertension and depressed RV, may be considered to improve the patient's clinical course during pump support.     

Temporal trends and outcomes of patients waiting on left ventricular assist devices and inotropes for heart transplantation

We sought to evaluate the trends and outcomes of patients with left ventricular assist devices (LVADs) and inotropes at the time of listing for heart transplantation. Adults with an LVAD implanted and listed with 1A status were identified in the United Network for Organ Sharing (UNOS) registry between 2010 and 2017. Patients were grouped according to the presence or absence of inotropes at the time of listing and transplantation. A total of 2714 patients were included in the study including 664 patients on inotropes at the time of listing, 235 at the time of transplantation, and 118 on inotropes both at listing and at the time of transplantation. Patients on LVAD and inotropes at the time of listing were more frequently supported with a right ventricular assist device (RVAD) (P < .001), had higher risk of death in the waiting list (sub-hazard ratio [SHR] = 1.48, 95% CI 1.14-1.90, P = .002), and were less likely to be transplanted (SHR = 0.70, 95% CI 0.63-0.78, P < .001) compared with those not on inotropes, after adjusting for described confounders. Approximately 1 in 10 LVAD recipients listed as status 1A are on inotropic therapy at the time of heart transplantation. Patients on LVAD and inotropes have worse outcomes in terms of survival and lower rates of transplantation.     

Outcomes in Patients With HeartMate3 Versus HeartWare Ventricular Assist Device Implanted as Destination Therapy

BackgroundDonor organ shortage caused a growing interest in mechanical circulatory support not only as a bridge to transplant but also as a destination therapy. Improved results and increased applicability and durability of left ventricular assist devices (LVADs) have established this treatment option as an alternative for patients with end-stage heart failure.MethodsThe aim of the study was to compare the early results, major complications, and the follow up of all patients undergoing HeartMate3 (HM3) LVAD and HeartWare Ventricular Assist Device (HVAD) system implantation in one of the most experienced Clinic in Poland between 2015 and 2020.ResultsThere were 78 individuals (72 male, 92%; 6 female, 8%), with median age 57 years (range, 50-62 years). Until 2020 we implanted 47 (60%) HVADs and 31 (40%) HM3 LVADs. Patient characteristics were comparable between both groups apart from median left ventricle diameter (8.2 cm [range, 7.4-8.4 cm] in HM3 group vs 7.2 cm [range, 6.7-7.9 cm] in HVAD group; P < .01) The overall survival was 53.2% in the HVAD group and 77.4% in the HM3 group (P =.03). Mean survival time was higher in HM3 group (2.97 years [range, 2.43-3.5 years] vs 2.51 years [range, 1.94-3.08 years]; P < .05). Mean complication-free survival time was also higher in the HM3 group (2.16 years [range, 1.55-2.76] vs 1.61 [range, 1.16-2.06 years]; P < .05), with overall complication-free rate of 54.8% for HM3 vs 29.8% for HVAD (P = .27). Median hospitalization time was comparable (31 days [range, 25-39 days] in the HM3 group vs 32 days [range, 24-38 days] in the HVAD group; P = .49).ConclusionsPatients supported with the HM3 had significantly fewer major complications than HVAD. Moreover, the HVAD was associated with higher mortality.     

Cluster analysis of preoperative echocardiographic findings and outcomes following left ventricular device implantation

Objective

To investigate whether preoperative echocardiography findings determine postoperative continuous-flow left ventricular assist device outcomes.

Outcomes in Patients Receiving HeartMate II Versus HVAD Left Ventricular Assist Device as a Bridge to Transplantation

Objective

Ventricular assist devices have become a standard treatment for patients with advanced heart failure. We present data comparing results after implantation of HeartMate II (HM II) versus HVAD (HW) left ventricular assist devices (LVADs) for the past 7 years at our institution.

Methods

From July 2006 to August 2012, 121 consecutive patients underwent LVAD implantation: 70 (57.9%) received HM II and 51 (42.1%) HW. Patient demographics, perioperative characteristics, and laboratory parameters as well as postoperative outcome were compared retrospectively.

Results

Patients in the HM II group were significantly younger (P < .01), with more deranged liver function (higher bilirubin [P = .02] and alanine aminotransferase [P = .01] levels), and had a significantly higher rate of preoperative infections requiring antibiotic treatment (P = .02) and a higher body core temperature (P < .01). Other demographic and preoperative parameters did not show statistical differences. Most postoperative characteristics were also similar between the two groups. HM II patients had a significantly higher transfusion rate, but there were no differences in incidence of resternotomy (P = .156). Recovery and VAD explantation were more likely in the HM II group (P = .02). Although there was no significant difference in survival (log rank test: P = .986; Breslow test: P = .827), HM II patients were more likely to develop a percutaneous site infection (P = .01).

Conclusions

Both HM II and HW provide similar early postoperative outcome and good long-term survival. The differences observed between the groups may be related to demographic and preoperative factors rather than the type of the device used.     

Clinical characteristics and outcomes of patients requiring prolonged inotropes after left ventricular assist device implantation

Limited data exist regarding patients with continuous-flow left ventricular assist device (LVAD) support who require long-term inotropes. Our primary objective was to evaluate the clinical characteristics and all-cause mortality of LVAD recipients with prolonged inotrope use (PIU). Secondary endpoints were to compare predictors of PIU, mortality, risk of late re-initiation of inotropes, time to gastrointestinal bleed (GIB), infection, and arrhythmias. Retrospective cohort study was conducted on adult patients with primary continuous-flow LVADs implanted from January 2008 to February 2017 and the patients were followed up through February 2018. We defined PIU as ≥14 days of inotrope support. Kaplan–Meier method, competing risk models and Cox proportional hazard models were used. Final analytic sample was 203 patients, 58% required PIU, and 10% were discharged on inotropes. There was no difference in preimplant characteristics. One-year survival rate was 87% if no PIU required, 74% if PIU required, and 72% if discharged on inotropes. PIU was associated with longer length of stay and higher incidence of GIB. We found no association between PIU and late re-initiation of inotropes, infection or arrhythmias. Adjusted hazard risk of death was increased in patients with PIU (HR = 1.66, P = .046), older age (HR = 1.28, P = .031), and higher creatinine levels (HR = 1.60, P = .007). Prolonged inotrope use is frequently encountered following LVAD implantation and is associated with adverse prognosis but remains a therapeutic option. Inability to wean inotropes prior to hospital discharge is a marker of patients at particularly higher risk of mortality following LVAD implantation.     

Spleen size improvement in advanced heart failure patients using a left ventricular assist device

The spleen has been recognized as an important organ that holds a reserve of 20% to 30% of the total blood volume. Spleen contraction and splenic volume reduction occur in patients with hypovolemic shock. However, the change in the spleen volume and the association between spleen size and hemodynamic parameters remain unclear in patients with advanced heart failure (HF) who need left ventricular assist device (LVAD) support. This study was performed to investigate the change in spleen size and the relationship between spleen size and hemodynamic parameters before and after LVAD implantation in patients with advanced HF. We enrolled 20 patients with advanced HF on LVAD support. All patients underwent right heart catheterization and computed tomography before and after LVAD implantation. The spleen size was measured by computed tomography volumetry. We excluded patients with a mean right atrial pressure (RAP) of <5 mm Hg because of the possibility of hypovolemia and those with a cardiac index of >2.2 L/min/m² before LVAD implantation. The splenic volume significantly increased from 160.6 ± 46.9 mL before LVAD implantation to 224.6 ± 73.5 mL after LVAD implantation (P < .001). Before LVAD implantation, there was a significant negative correlation between spleen volume and systemic vascular resistance (SVR). After LVAD implantation, however, there were significant correlations between spleen volume and the cardiac index, RAP, and pulmonary capillary wedge pressure despite the absence of a significant correlation between spleen volume and SVR. Furthermore, one patient developed reworsening HF because of LVAD failure due to pump thrombosis. In this case, the splenic volume was 212 mL before LVAD implantation and increased to 418 mL after LVAD implantation, although it decreased to 227 mL after LVAD failure. The spleen size may change depending on hemodynamics in patients with advanced HF with LVAD support, reflecting sympathetic nerve activity and the systemic volume status.     

Durable left ventricular assist device implantation in extremely obese heart failure patients

Left ventricular assist devices (LVADs) have improved clinical outcomes and quality of life for those with end‐stage heart failure. However, the costs and risks associated with these devices necessitate appropriate patient selection. LVAD candidates are becoming increasingly more obese and there are conflicting reports regarding obesity’s effect on outcomes. Hence, we sought to evaluate the impact of extreme obesity on clinical outcomes after LVAD placement. Consecutive LVAD implantation patients at our center from June 2008 to May 2016 were studied retrospectively. We compared patients with a body mass index (BMI) ≥40 kg/m² (extremely obese) to those with BMI < 40 kg/m² with respect to patient characteristics and surgical outcomes, including survival. 252 patients were included in this analysis, 30 (11.9%) of whom met the definition of extreme obesity. We found that patients with extreme obesity were significantly younger (47[33, 57] vs. 60[52, 67] years, P < 0.001) with fewer prior sternotomies (16.7% vs. 36.0%, P = 0.04). They had higher rates of pump thrombosis (30% vs. 9.0%, P = 0.003) and stage 2/3 acute kidney injury (46.7% vs. 27.0%, P = 0.003), but there were no differences in 30‐day or 1‐year survival, even after adjusting for age and clinical factors. Extreme obesity does not appear to place LVAD implantation patients at a higher risk for mortality compared to those who are not extremely obese; however, extreme obesity was associated with an increased risk of pump thrombosis, suggesting that these patients may require additional care to reduce the need for urgent device exchange.     

Outcome analysis for prediction of intraaortic balloon pump support failure and long-term survival in high-risk patients undergoing mitral valve surgery

The outcome predictors of intra-aortic balloon pump (IABP) in patients who undergo mitral valve surgery remain unknown. This study aimed to retrospectively review valvular surgery in patients who received an IABP to identify the predictors of failure of IABP support and anticipate the necessary therapy. This retrospective observational study recruited a total of 157 consecutive patients who underwent open-heart mitral valve surgery with IABP implantation intraoperatively or postoperatively. Univariate and multivariate logistic regression analyses were performed to identify the risk factors attributed to 30-day mortality. Follow-up data of survivors were collected to investigate the effect of IABP support to evaluate long-term outcomes. The overall 30-day mortality was 35.7% (56 patients). The following factors that contributed to 30-day mortality included sepsis (P < .001, OR: 5.627, 95%CI: 2.422-11.683); IABP implantation postoperatively rather than intraoperatively (P = .001, OR: 6.395, 95%CI: 2.085-19.511); right heart failure (P = .042, OR: 3.419, 95%CI: 1.225-12.257); and lack of subvalvular apparatus preservation (P = .033, OR: 3.710, 95%CI: 1.094-13.167). Furthermore, follow-up data of these patients showed an estimation of 5-year and 10-year survival rates of 58.9% and 35.7%, respectively. Patients with intraoperative IABP demonstrated better long-term survival outcomes when compared to those with postoperative IABP (χ² = 4.291, P = .038). In summary, this study distinguished the preoperative predictors of 30-day mortality of IABP-support in mitral valve surgery patients. These results indicated that early intervention with IABP should be taken into consideration in case of hemodynamic instability in critically ill patients undergoing mitral valve surgery.     

Long-term clinical outcome of mitral valve repair in asymptomatic severe mitral regurgitation

Objective: To assess the long-term survival, the incidence of cardiac complications and the factors that predict outcome in asymptomatic patients with severe degenerative mitral regurgitation (MR) undergoing mitral valve repair. Methods: Up to 143 asymptomatic patients (mean age 63 ± 12 years) with severe degenerative MR who underwent mitral valve repair between 1990 and 2001 were subsequently followed up for a median of 8 years. The study population was subdivided into three subgroups: patients with left ventricular (LV) dysfunction and/or dilatation (n = 18), patients with atrial fibrillation and/or pulmonary hypertension (n = 44) and patients without MR-related complications (n = 81). Results: For the patients, 10-year overall and cardiovascular survival was 82 ± 4% and 90 ± 3%. At 10 years, patients without preoperative MR-related complications had significantly better overall survival than patients with preoperative LV dysfunction and/or dilatation (89 ± 4% vs 57 ± 13%, log rank p = 0.001). Patients without preoperative MR-related complications also tended to have a better 10-year overall and cardiovascular survival than patients with atrial fibrillation and/or pulmonary hypertension (overall survival of 79 ± 8%), although this did not reach statistical significance (log rank p = 0.17). Cox regression analysis identified the baseline left ventricular ejection fraction and age as the sole independent predictors of outcome. Conclusion: Our data indicate that in asymptomatic patients with severe degenerative MR, mitral valve repair is associated with an excellent long-term prognosis. Nonetheless, the presence of preoperative MR-related complications, in particular LV dysfunction and/or dilatation, greatly attenuates the benefits of surgery. This suggests that mitral valve repair should be performed early, before any MR-related complications ensue.     

Effect of tobacco smoking on outcomes after left ventricular assist device implantation

Despite the well-established correlation between the tobacco use and cardiovascular disease, little is known about postoperative outcomes following the left ventricular assist device (LVAD) implantation. We aimed to elucidate the effect of tobacco smoking on post-LVAD implant outcomes. Patients who received LVADs from 2013 to 2018 were retrospectively characterized as current, former, or never smokers at the time of implant. We examined 1-year survival, total hospital readmissions, and specific hospital readmissions for LVAD-related adverse events based on patient's smoking status. Of the enrolled patients (n = 292), 55% were former smokers, 33% were never smokers, and 11% were current smokers. The majority of patients were African-American (48%) with a median age of 58 years. Never smokers were younger and less likely to be Caucasian compared to former or current smokers (P < .05, for both). The category of former smokers had statistically comparable total readmission rates with never smokers (2.49 vs. 2.13 event/year), whereas current smokers had significantly higher rates compared to never smokers (2.81 events/year, P < .05), with odds ratio 2.12 (95% CI = 1.35-3.32) adjusted for age and Caucasian race for >5 times of total readmissions per year. The rates of driveline infection, stroke, and hemolysis were statistically comparable between the never smokers and former smokers, while current smokers had significantly higher rates compared to never smokers (P < .05 for all).     

Effect of left ventricular assist device implantation on right ventricular function: Assessment based on right ventricular pressure–volume curves

Right ventricular (RV) failure is significantly associated with morbidity and mortality after left ventricular assist device (LVAD) implantation. However, it remains unclear whether LVAD implantation could worsen RV function. Therefore, we aimed to investigate the effect of LVAD implantation on RV function by comparing RV energetics derived from the RV pressure–volume curve between before and after LVAD implantation. This exploratory observational study was performed between September 2016 and January 2018 at a national center in Japan. Twenty-two patients who underwent LVAD implantation were included in the analysis. We measured RV energetics parameters: RV stroke work index (RVSWI), which was calculated by integrating the area within the RV pressure–volume curve; RV minute work index (RVMWI), which was calculated as RVSWI × heart rate; and right ventriculo–arterial coupling, which was estimated as RV stroke volume/RV end-systolic volume. We compared RV energetics between before and after LVAD implantation. Although RVSWI was similar [424.4 mm Hg · mL/m² (269.5-510.3) vs. 379.9 mm Hg · mL/m² (313.1-608.8), P = 0.485], RVMWI was significantly higher after LVAD implantation [29 834.1 mm Hg · mL/m²/min (18 272.2-36 357.1) vs. 38 544.8 mm Hg · mL/m²/min (29 016.0-57 282.8), P = 0.001], corresponding to a significantly higher cardiac index [2.0 L/min/m² (1.4-2.2) vs. 3.7 L/min/m² (3.3-4.1), P < 0.001] to match LVAD flow. Right ventriculo–arterial coupling was significantly higher after LVAD implantation [0.360 (0.224-0.506) vs. 0.480 (0.343-0.669), P = 0.025], suggesting that the efficiency of RV performance improved. In conclusion, higher RVMWI with higher cardiac index to match LVAD flow and improved efficiency of RV performance indicate that LVAD implantation might not worsen RV function.     

Concomitant Tricuspid Valve Repair or Replacement During Left Ventricular Assist Device Implant Demonstrates Comparable Outcomes in the Long Term

Abstract Introduction: Severe tricuspid regurgitation (TR) is present in nearly half the patients undergoing implant of a left ventricular assist device (LVAD) and its correction confers better long‐term outcome. Aim: To compare the early and late results of tricuspid valve repair (TVrpr) or replacement (TVR) with LVAD implant. Patient and Methods: Sixty‐four from a cohort of 126 patients had a concomitant tricuspid valve procedure; 48 (75%) underwent a TVrpr whereas 16 (25%) had TVR. All preoperative hemodynamic parameters including the mean TR grade (TVrpr; 3.6 vs. TVR; 3.7) were comparable (p = 0.7). The mean TR grade was 1.6 ± 1.5 for the remaining 62 patients who did not have a concomitant tricuspid valve procedure, with 4/62 (6%) having severe TR (p < 0.0001). Results: Cardiopulmonary bypass time was longer for patients undergoing TVR (p = 0.01). There was a significant reduction in right atrial pressure for the entire cohort (p < 0.01) and the postoperative right atrial pressure was not statistically different between TVrpr (13.6 ± 4.6) and TVR (11.6 ± 4.3; p = 0.6. Postoperative intensive care unit stay was comparable as was the duration of inotropic support (p = 0.5) or need for temporary right ventricular mechanical support. In‐hospital mortality (12%) was not different between groups. The mean time for LVAD support was 12.3 ± 9.71 months and the last transthoracic echocardiographic examination was performed at mean intervals of 13.8 ± 10.8 months (TVrpr) and 11.8 ± 7.6 months (TVR; p = 0.47). Reduction in TR grade was similar between groups (p = 0.27). Late mortality (p = 1.00) was comparable in both groups. Using log‐rank analysis, there was no significant difference in the estimated survival between TVrpr and TVR (p = 0.88). Conclusion: TVrpr repair at the time of LVAD implant is effective in correcting TR even at the end of one year of follow‐up. The choice to repair or replace does not affect the clinical outcome. (J Card Surg 2012;27:760‐766)     

Impact of turbulent blood flow in the aortic root on de novo aortic insufficiency during continuous-flow left ventricular-assist device support

Severe aortic insufficiency (AI) after implantation of continuous-flow left ventricular-assist device (LVAD) affects device performance and outcomes. However, the mechanism for the occurrence and progression of AI has not been elucidated. We investigated the impact of nonphysiological retrograde blood flow in the aortic root on AI after LVAD implantation. Blood flow pattern was analyzed in patients with and without AI (n = 3 each) who underwent LVAD implantation, by computational fluid dynamics with patient-specific geometries, which were reproduced using electrocardiogram-gated 320-slice computed tomographic images. The total volume of retrograde blood flow during one cardiac cycle (716 ± 88 mL) was higher and the volume of slow blood flow (<0.1 cm/s) (0.16 ± 0.04 cm³) was lower in patients with AI than in those without AI (360 ± 111 mL, P = .0495, and 0.49 ± 0.08 cm³, P = .0495, respectively). No significant difference in wall shear stress on the aortic valve was observed between the groups. Patients with AI had a perpendicular anastomosis at the distal ascending aorta and the simulation in the modified anastomosis model of patients with AI showed that the retrograde blood flow pattern depended on the angle and position of anastomosis. Computational fluid dynamics revealed strong retrograde blood flow in the ascending aorta and aortic root in patients with AI after LVAD implantation. The angle and position of LVAD outflow anastomosis might impact retrograde blood flow and de novo AI after LVAD implantation.     

Continuous LVAD monitoring reveals high suction rates in clinically stable outpatients

Suction of the left ventricle can lead to potentially life-threatening events in left ventricular assist device (LVAD) patients. With the resolution of currently available clinical LVAD monitoring healthcare professionals are unable to evaluate patients’ suction occurrences in detail. This study investigates occurrences and durations of suction events and their associations with tachycardia in stable outpatients. Continuous high-resolution LVAD data from HVAD patients were analyzed in the early outpatient period for 15 days. A validated suction detection from LVAD signals was used. Suction events were evaluated as suction rates, bursts of consecutive suction beats, and clusters of suction beats. The occurrence of tachycardia was analyzed before, during, and after suction clusters. Furthermore, blood work, implant strategy, LVAD speed setting, inflow cannula position, left ventricular diameters, and adverse events were evaluated in these patients. LVAD data of 10 patients was analyzed starting at 78 ± 22 postoperative days. Individuals’ highest suction rates per hour resulted in a median of 11% (range 3%-61%). Bursts categorized as consecutive suction beats with n = 2, n = 3-5, n = 6-15, and n > 15 beats were homogenously distributed with 10.3 ± 0.8% among all suction beats. Larger suction bursts were followed by shorter suction-free periods. Tachycardia during suction occurred in 12% of all suction clusters. Significant differences in clinical parameters between individuals with high and low suction rates were only observed in left ventricular end-diastolic and end-systolic diameters (P < .02). Continuous high-resolution LVAD monitoring sheds light on outpatient suction occurrences. Interindividual and intraindividual characteristics of longitudinal suction rates were observed. Longer suction clusters have higher probabilities of tachycardia within the cluster and more severe types of suction waveforms. This work shows the necessity of improved LVAD monitoring and the implementation of an LVAD speed control to reduce suction rates and their concomitant burden on the cardiovascular system.     

T cell–mediated rejection is a major determinant of inflammation in scarred areas in kidney allografts

Inflammation in fibrosis areas (i‐IF/TA) of kidney allografts is associated with allograft loss; however, its diagnostic significance remains to be determined. We investigated the clinicohistologic phenotype and determinants of i‐IF/TA in a prospective cohort of 1539 kidney recipients undergoing evaluation of i‐IF/TA and tubulitis in atrophic tubules (t‐IF/TA) on protocol allograft biopsies performed at 1 year posttransplantation. We considered donor, recipient, and transplant characteristics, immunosuppression, and histological diagnoses in 2260 indication biopsies performed within the first year posttransplantation. Nine hundred forty‐six (61.5%) patients presented interstitial fibrosis/tubular atrophy (IF/TA Banff grade > 0) at 1 year posttransplant, among whom 394 (41.6%) showed i‐IF/TA. i‐IF/TA correlated with concurrent t‐IF/TA (P < .001), interstitial inflammation (P < .001), tubulitis (P < .001), total inflammation (P < .001), peritubular capillaritis (P < .001), interstitial fibrosis (P < .001), and tubular atrophy (P = .02). The independent determinants of i‐IF/TA were previous T cell–mediated rejection (TCMR) (P < .001), BK virus nephropathy (P = .007), steroid therapy (P = .039), calcineurin inhibitor therapy (P = .011), inosine‐5′‐monophosphate dehydrogenase inhibitor therapy (P = .011), HLA‐B mismatches (P = .012), and HLA‐DR mismatches (P = .044). TCMR patients with i‐IF/TA on posttreatment biopsy (N = 83/136, 61.0%) exhibited accelerated progression of IF/TA over time (P = .01) and decreased 8‐year allograft survival (70.8% vs 83.5%, P = .038) compared to those without posttreatment i‐IF/TA. Our results support that i‐IF/TA may represent a manifestation of chronic active TCMR.     

A novel,highly discriminatory risk model predicting acute severe right ventricular failure in patients undergoing continuous‐flow left ventricular assist device implant

Various risk models with differing discriminatory power and predictive accuracy have been used to predict right ventricular failure (RVF) after left ventricular assist device (LVAD) placement. There remains an unmet need for a contemporary risk score for continuous flow (CF)‐LVADs. We sought to independently validate and compare existing risk models in a large cohort of patients and develop a simple, yet highly predictive risk score for acute, severe RVF. Data from the Mechanical Circulatory Support Research Network (MCSRN) registry, consisting of patients who underwent CF‐LVAD implantation, were randomly divided into equal‐sized derivation and validation samples. RVF scores were calculated for the entire sample, and the need for a right ventricular assist device (RVAD) was the primary endpoint. Candidate predictors from the derivation sample were subjected to backward stepwise logistic regression until the model with lowest Akaike information criterion value was identified. A risk score was developed based on the identified variables and their respective regression coefficients. Between May 2004 and September 2014, 734 patients underwent implantation of CF‐LVADs [HeartMate II LVAD, 76% (n = 560), HeartWare HVAD, 24% (n = 174)]. A RVAD was required in 4.5% (n = 33) of the patients [Derivation cohort, n = 15 (4.3%); Validation cohort, n = 18 (5.2%); P = 0.68)]. 19.5% of the patients (n = 143) were female, median age at implant was 59 years (IQR, 49.4–65.3), and median INTERMACS profile was 3 (IQR, 2–3). RVAD was required in 4.5% (n = 33) of the patients. Correlates of acute, severe RVF in the final model included heart rate, albumin, BUN, WBC, cardiac index, and TR severity. Areas under the curves (AUC) for most commonly used risk predictors ranged from 0.61 to 0.78. The AUC for the new model was 0.89 in the derivation and 0.92 in the validation cohort. Proposed risk model provides very high discriminatory power predicting acute severe right ventricular failure and can be reliably applied to patients undergoing placement of contemporary continuous flow left ventricular assist devices.