Pagani, Francis D.

Background Postoperative atrial fibrillation occurs in ~40% after cardiac surgery. Mineralocorticoid receptor antagonists (MRA) are known to reduce chronic atrial fibrillation (AF) development and burden. We evaluated the association of preoperative MRA use with postoperative atrial fibrillation and investigated atrial cell types modulated by MRAs during cold preservation. Methods We studied 19 042 cardiac surgery patients at Mayo Clinic. Propensity 1:3 matching identified 298 MRA users and 894 non‐users. A subgroup analysis of patients on any preoperative diuretic was performed to isolate cardiac‐specific effects of MRAs, matching 298 MRA users to 894 non‐MRA diuretic users. AF recurrence was assessed for up to 6‐years. Single‐nucleus RNA sequencing (snRNA‐seq) was performed on human donor atria exposed to canrenone (a water‐soluble MRA) during cold preservation with ex‐vivo reperfusion, and expression profiles were compared with atria from patients with AF. Results After matching, preoperative MRA use was associated with a lower incidence of postoperative atrial fibrillation (19.8% versus 31.8%, P <0.001). In the diuretic‐only subgroup, MRA users also had lower postoperative atrial fibrillation (19.8% versus 33.2%, P <0.001). MRA use was associated with a reduced incidence of paroxysmal and chronic AF at 6‐years. snRNA‐seq identified a cardiomyocyte subpopulation, CM2, with high mineralocorticoid receptor expression where canrenone suppressed cold preservation‐induced mineralocorticoid receptor target gene expression, which was conversely elevated in chronic AF. Canrenone also attenuated stress‐response in atrial macrophages and pericytes. Conclusions Preoperative MRAs were associated with reduced postoperative and long‐term AF after cardiac surgery. Mechanistically, our ex‐vivo human atrial model revealed that MRAs suppress mineralocorticoid receptor ‐driven atrial stress responses, particularly in conduction‐relevant cardiomyocytes.

Abstract Background New postoperative atrial fibrillation (POAF) occurs in about 40% after cardiac surgery. Mineralocorticoid receptor antagonists (MRA) are known to reduce chronic atrial fibrillation (AF) development and burden. We examined the impact of preoperative MRA use on POAF and also examine the atrial cell type impacted by MRA treatment during cold cardiac preservation. Methods Retrospective study of 19,042 patients who underwent cardiac surgery at Mayo Clinic in Minnesota, and performed 1:3 propensity matching to obtain 298 patients on preoperative MRA matched to 894 who were not. We also separately matched patients using preoperative diuretics. Single-nuclei RNA sequencing (snRNA-seq) examined MRA’s effects on different atrial cell types in canrenone (water soluble MRA) treated human donor hearts undergoing cold preservation followed by ex-vivo reperfusion and compared gene expression to the atria of patients with AF. Results Propensity matched preoperative MRA group had less new onset POAF (19.8% vs 31.5%, P<0.001). To account for the possibility that preoperative diuretic use and volume reduction may impact POAF, we propensity matched 298 preop diuretic users that included MRA use to another 894 patients who used a non-MRA diuretic preoperatively. Those who used preoperative MRA similarly had a lower incidence of POAF (19.8% vs 33.2%, P<0.001). No survival difference was present between the propensity matched groups that used preoperative diuretics (P=0.079). Preoperative MRA use also reduced the development of paroxysmal and chronic AF at 6 years of follow up. From our snRNA-seq data, we identified a subpopulation of atrial cardiomyocytes (CM2) that had high MR expression where canrenone suppressed the increase in MR target gene expression associated with cold preservation-reperfusion. These MR targets were conversely elevated in patients with chronic AF. Canrenone also suppressed other cardiac preservation associated genes that show elevated expression in atrial macrophages and pericytes from chronic AF atria. Conclusions Our studies show that preoperative MRA use is associated with 40% reduction in POAF as well as lowering long standing AF development by about 41%. Our cold cadiac preservation-reperfusion model showed that canrenone reduced expression of MR target genes associated with chronic AF, particular in cardiomyocytes with important roles in electrical conduction. Clinical Perspective What is New? This study shows that preoperative use of mineralocorticoid receptors antagonists (MRA) is associated with a reduced incidence of new onset perioperative atrial fibrillation after cardiac surgery utilizing cardiopulmonary bypass. We show that preoperative MRA use is associated with a lower incidence of developing more chronic paroxymal or sustained atrial fibrillation. Addition of canrenone, a clinically utilized water soluble MRA, to cardioplegia solution used during cardiac preservation can attenuate atrial inflammatory reponses and reduce signaling through molecular pathways that promote atrial fibrillation. What are the clinical implications? Perioperative use of MRAs may be considered to reduce early postoperative atrial fibrillation as well as lowering the risk of developing more chronic atrial arrhythmias. These findings support pursuing a clinical trial to determine the impact of MRA use on atrial arrhythmias following cardiac surgery in the setting of cardiopulmonary bypass with cold cardiac preservation.

ImportanceThe advanced ambulatory heart failure (HF) population comprises patients who have progressed beyond the pillars of recommended stage C HF therapies but can still find meaningful life-years ahead. Although these patients are commonly encountered in practice, national databases selectively capture the small groups accepted for heart transplant listing or left ventricular assist devices. The epidemiology, trajectories, and therapies for other ambulatory patients with advanced HF are poorly understood.ObservationsIn December 2022, the National Heart, Lung and Blood Institute convened a team of experts to identify knowledge gaps and research priorities for the ambulatory population with limiting daily symptoms and transition toward refractory end-stage D HF, designated as stage C2D. This article summarizes the findings from that 3-day workshop. Workshop participants surveyed the initial challenges and knowledge gaps for (1) recognition of ambulatory C2D HF, (2) estimation of the magnitude of the affected population and identifiable subpopulations, and (3) physiologic phenotypes, such as low cardiac output, right HF, cardiorenal syndromes, congestive hepatopathy and frailty, which offer distinct targets for existing and emerging therapies. Social drivers of HF and patient preferences for quality/length of survival were highlighted as essential modifiers for personalization of therapies.Conclusions and RelevanceTen key points summarized workshop findings, with target cohorts for study proposed as a crucial next step. This workshop summary is intended as a call for action to address knowledge gaps and develop new strategies to improve outcomes in the large ambulatory population with C2D HF.

Introduction: Age ≥ 70 is used to exclude patients from cardiac transplantation. Elderly patients may be offered left ventricular assist device (LVAD) therapy as an alternative. It remains poorly defined how they respond to LVAD support. Hypothesis: Elderly patients have LVAD outcomes that are non-inferior to younger patients. Methods: Data on 1,149 continuous-flow LVAD recipients from May 2004 to May 2015 was pooled from the Mechanical Circulatory Support Research Network (MCSRN). Groups were assigned based on Age ≥ 70 (n = 163) and < 70 (n = 986). Results: Patients age ≥ 70 were more likely to be male (91%), have an ischemic cardiomyopathy (71%), atrial fibrillation (41%), hypertension (66%), diabetes (38%) and prior sternotomy (45%). Older patients also had a lower BMI and higher creatinine, 26.7 ± 0.4 v. 29.9 ± 0.5 and 1.46 ± 0.04 v. 1.35 ± 0.02, p < 0.05. The hazard ratio for mortality was highest in elderly patients in the early post-operative period and stabilized over time with no long-term differences in survival, p = 0.18, Figure 1a. Elderly patients had equivalent rates of device thrombosis and stroke, p = 0.47 and 0.44, Figures 1b-c. Survival free of gastrointestinal bleeding (GIB) at 1-year was 58% in elderly patients compared to 69% in younger patients, Figure 1d, p < 0.01. Multivariate cox regression revealed that age ≥ 70 was not a significant predictor of mortality (HR 0.93, 95% CI 0.69 - 1.25, p = 0.62), but pre-operative creatinine (HR 1.54, 95% CI 1.28 - 1.86, p < 0.01) and bilirubin (HR 1.2, 95% CI 1.03 - 1.4, p = 0.02) were. When age was considered a continuous variable, the HR was 1.2 (95% CI 1.07 - 1.3 per 10y, p < 0.01). Conclusions: Elderly patients, age ≥ 70, have equivalent long-term survival after LVAD implantation with similar rates of device thrombosis and stroke. Rates of GIB were higher in the elderly and this finding warrants caution when choosing anti-coagulation protocols in the elderly. Overall age ≥ 70 does not portend a poorer survival after LVAD implant.

Introduction: Advanced age is a risk factor for poor outcomes following left ventricular assist device (LVAD) implant. A means of identifying elderly patients with acceptable mortality risk following LVAD surgery is not currently available. The HeartMate II (HMII) Risk Score (HMRS) was recently developed and validated, providing good risk discrimination for predicting survival in patients undergoing HMII implant. Independent survival predictors in the model included age and markers of renal function, coagulopathy and nutrition. We hypothesize that the HMRS will provide utility for risk stratification of the elderly LVAD candidate. Methods: Elderly patients (age >65 years) enrolled into the HMII Destination Therapy (DT) and Bridge to Transplant trials were selected for the study (n=444). Complete data for HMRS calculation was available in 98% (n=435). Preoperative patient HMRS was calculated according to the formula: HMRS = ln(1.29)*decade of age + ln(0.71)*Albumin + ln(1.37)*Cr + ln(1.86)*INR + ln(0.52)*LVAD Center Volume >=15 + ln(0.67)*Implant after 2007. Patients were trichotimized into high (HMRS >1.0), medium (HMRS 0.50-1.0), and low (HMRS <=0.50) risk categories (as previously defined in model development) based on HMRS. The primary endpoint was survival at 1 year following LVAD implant, estimated using Kaplan-Meier methods. Results: The mean cohort age was 71±4 years and 84% (n=372) had devices implanted for DT. The table shows the HMRS along with mean±stddev values for the score's components. All between-group differences were statistically significant (Kruskal-Wallis p<0.05), although differences in age were not clinically significant. Survival based on HMRS strata is shown in the figure. Patients in the low and medium risk groups had survivals >80% at 1 year following LVAD implant. Conclusions: The HMRS can be used to identify elderly patients with survivals comparable to that of the general LVAD population.

Abstract Background Hemocompatibility‐related adverse events (HRAE) negatively influence survival. However, no study has examined the impact of these events on health‐related quality of life (HRQOL) and functional outcomes following continuous‐flow left ventricular assist device implantation (CF‐LVAD). We assessed the impact of HRAE events on HRQOL and hypothesized that HRAE's adversely impact HRQOL and functional outcomes. Methods INTERMACS database identified patients undergoing primary CF‐LVAD implantation from 2008 to 2017. HRAEs included stroke, non‐surgical bleeding, hemolysis, and pump thrombosis and were identified as defined in the literature. HRAEs were further stratified as Tier 1–2 and disabling stroke events. Time‐series analysis was executed for HRAE patients with values pre‐HRAE, post‐HRAE, and closest to 12 months follow up. Local polynomial regression curves modeling individual patients were superimposed into “spaghetti” plots. Results All HRQOL and functional metrics improved in patients over time, despite HRAE complications. However, these patient metrics were significantly reduced compared to the non‐HRAE cohort. Advanced data visualization techniques noted a decline after experiencing an HRAE with a subsequent recovery to baseline levels or higher. Six‐minute walk test (6MWT) was noted to be most affected in the post‐HRAE period but recovered similar to other metrics. Conclusions The burden of HRAE following CF‐LVAD implantation did not negatively impact the quality of life. However, the 6MWT did not increase in the post‐HRAE period in all HRAE patients. Improvement of heart failure symptoms after CF‐LVAD coupled with optimal management following the HRAE act to preserve the enhanced quality of life.

Introduction: Various risk models have been used to predict mortality after implantation of continuous-flow ventricular assist devices (CF-VADs). Discriminatory power and predictive accuracy vary, and there is a need to develop and validate a contemporary risk score in a large multicenter patient cohort. Hypothesis: We sought to develop an early mortality risk score utilizing a large voluntary research registry of patients implanted with CF-VADs, with the focus on increased discriminatory power. Methods: From May 2004 to May 2015, 1150 patients in the Mechanical Circulatory Support Research Network (MCSRN) registry were randomly divided into equal-sized derivation and validation samples (n=575, each group). Candidate predictors from the derivation sample were subjected to backward stepwise logistic regression until the model with lowest Akaike information criterion value was identified for predicting 90-day mortality. A risk score was developed based on the variables and their respective regression coefficients in the final model. Discriminatory power of the risk score was evaluated using receiver operating characteristic analysis, and calibration was assessed using Hosmer-Lemeshow goodness of fit test. Results: Overall 90-day mortality was 9.4% (n=99). The final logistic regression model consisted of 9 predictors: Age at implant, preoperative mechanical ventilation, serum total bilirubin, hemoglobin, tricuspid valve regurgitation severity, left ventricular end-diastolic diameter, cardiac index, pulmonary capillary wedge pressure, and destination therapy (DT) as an indication for pump placement. The area under the curve was 0.86 in the derivation sample (95% CI, 0.75-0.97) and 0.75 in the validation sample (95% CI, 0.63-0.86). Hosmer-Lemeshow goodness of fit test yielded insignificant values in both samples (p=0.75, p=0.58) consistent with good calibration. Conclusions: The proposed 90-day mortality MCSRN risk score provides highest-to-date discriminatory power when compared to already published models. The risk score is applicable to a contemporary large cohort of patients implanted with CF-VADs for either indication (bridge or DT).

Introduction: Recent reports have documented an abrupt increase in 3-month confirmed HeartMate II left ventricular assist device (LVAD) thrombosis beginning in 2011 without a plateau observed to date. Because very little data exist from multi-institutional efforts, we report our experience. Methods: From January 2004 to December 2013, 516 pt underwent HeartMate II LVAD implant at three institutions (University of Michigan (n=254), Mayo Clinic Rochester (n=205), and Vanderbilt Heart and Vascular Institute (n=57)). Median age at implant was 60 yr (range, 18-82) and 428 (83%) were male. Confirmed pump thrombosis at 3 months was defined as thrombus found in the blood-contacting surfaces of the pump at the time of urgent transplant, device exchange or autopsy. Pt without at least 3 months of follow-up were excluded. Results: Confirmed pump thrombosis occurred in 9 pt within 3 months post implant. The incidence was greatest in the year 2012 (5.3%). Following this peak, the incidence of 3-month confirmed pump thrombosis decreased significantly to 2.9% (Figure). Significant differences in preoperative characteristics between patients with pump thrombosis and without thrombosis included female sex (36% vs. 16%, p=0.01), bridge to transplant (77% vs. 54%, p=0.03), atrial fibrillation (55% vs. 32%, p=0.04), and preop platelet count (231,000 vs. 172,000, p<0.001). Follow-up was available in all for a total of 857 patient years of support. At a median follow-up of 1.2 years (max., 9.8 years), a similar proportion of patients were alive (73% vs. 74%, p=0.9). Conclusions: We report a recent decrease in early, confirmed HeartMate II LVAD thrombosis to historically observed levels, which is disparate to recent reports. While we identified several differences in clinical characteristics between patient groups, the issue of pump thrombosis is complex and multifactorial. Most importantly, our findings demonstrate the need for more granular analyses from collaborative efforts.

Introduction: Axial and centrifugal-flow left ventricular assist devices (LVAD) have varied response to changes in loading conditions. Whether ventricular size modulates the response to LVAD therapy between the axial flow Heartmate II (HMII) and centrifugal flow Heartware (HVAD) is unknown. Hypothesis: Adverse event and survival rates between devices are affected by recipient pre-op left ventricular end-diastolic diameter (LVEDD). Methods: Data on 1,149 continuous-flow LVAD recipients from May 2004 to May 2015 was pooled from the Mechanical Circulatory Support Research Network (MCSRN). The effect of pre-op LVEDD on the instantaneous hazard of death and adverse events was evaluated between HMII (n=864) and HVAD (n=283). Results: The average LVEDD was 7.0cm and did not differ between the device recipients. Patients with a smaller LVEDD (≤ 6.3cm) were more likely female 39% v. 24% (p < 0.0001) and to have an ischemic cardiomyopathy (30% v. 24%, p = 0.045). For every 1cm increase in pre-op LVEDD, the adjusted hazard ratio (HR) for mortality increased with HVAD (HR 1.31, 95% CI 0.94-1.82, p = 0.005) and decreased with HMII (HR 0.78, 95% CI 0.67-0.92, p = 0.005), Figure 1a. Other predictors of mortality included age (HR 1.31, 95% CI 1.12 - 1.53 per 10y, p < 0.001) and bilirubin (HR 1.15, 95% CI 0.94-1.42 per mg/dL, p = 0.027). LVEDD by device type interaction was not a significant predictor of gastrointestinal bleeding or pump thrombosis. The risk of stroke increased with LVEDD for HVAD and decreased for HMII, but this did not reach statistical significance, Figure 1b. Ischemic etiology of heart failure (HR 1.7 95% CI 1.14 - 2.55, p = 0.01) and HVAD device use (HR 1.47 95% CI 1.00 - 2.17, p = 0.03) were significant predictors of stroke. Conclusions: Our data suggest important differences exist in patient outcomes between HMII and HVAD based on pre-op ventricular size. Studies are needed to determine if these differences in outcome are due to device or flow-specific differences in patient support.