Creation and Validation of a Novel Sex-Specific Mortality Risk Score in LVAD Recipients

Special Considerations for Advanced Heart Failure Surgeries: Durable Left Ventricular Devices and Heart Transplantation

Heart transplantation and durable left ventricular assist devices (LVADs) represent two definitive therapies for end-stage heart failure in the modern era. Despite technological advances, both treatment modalities continue to experience unique risks that impact surgical and perioperative decision-making. Here, we review special populations and factors that impact risk in LVAD and heart transplant surgery and examine critical decisions in the management of these patients. As both heart transplantation and the use of durable LVADs as destination therapy continue to increase, these considerations will be of increasing relevance in managing advanced heart failure and improving outcomes.

Validation of the Minnesota Pectoralis Risk Score to predict mortality in the HeartMate 3 population

BACKGROUND

The Minnesota Pectoralis Risk Score (MPRS) utilizes computed tomography-quantified thoracic muscle and clinical variables to predict survival after left ventricular assist device (LVAD) implantation. The model has not been prospectively tested in HeartMate 3 recipients.

METHODS

A single-center HeartMate 3 cohort from July 2016 to July 2021 (n = 108) was utilized for this analysis. Cohort subjects with complete covariates for MPRS calculation (pectoralis muscle measures, Black race, creatinine, total bilirubin, body mass index, bridge to transplant status, and presence/absence of contrast) implanted after MPRS development were included. MPRS were calculated on each subject. Receiver operating characteristic curves were generated to test model discrimination at 30-day, 90-day, and 1-year mortality post-LVAD. Next, the performance of the 1-year post-LVAD outcome was compared to the HeartMate 3 survival risk score (HM3RS).

RESULTS

The mean age was 58 (15 years), 80% (86/108) were male, and 26% (28/108) were destination therapy. The area under the curve (AUC) for the MPRS model to predict post-LVAD mortality was 0.73 at 30 days, 0.78 at 90 days, and 0.81 at 1 year. The AUC for the HM3RS for the 1-year outcome was 0.693. Each 1-unit point of the MPRS was associated with a significant increase in the hazard rate of death after LVAD (hazard ratio 2.1, 95% confidence interval 1.5-3.0, p < 0.0001).

CONCLUSIONS

The MPRS had high performance in this prospective validation, particularly with respect to 90-day and 1-year post-LVAD mortality. Such a tool can provide additional information regarding risk stratification to aid informed decision-making.

How to select a patient for LVAD

Left ventricular assist device (LVAD) implantation leads to improvement in symptoms and survival in patients with advanced heart failure. An important factor in improving outcomes post-LVAD implantation is optimal preoperative patient selection and optimization. In this review, we highlight the latest on the evaluation of patients with advanced heart failure for LVAD candidacy, including discussion of patient selection, implantation timing, laboratory and other testing considerations, and the importance of psychosocial evaluation. Such thorough evaluation by multidisciplinary team can serve to improve the outcomes of a complex group of patients with advanced heart failure being evaluated for LVAD.

Sex disparities in left ventricular assist device implantation outcomes: A systematic review and meta-analysis of over 50 000 patients

BACKGROUND

Left ventricular assist devices (LVAD) represent an important therapeutic option for patients progressing to end-stage heart failure. Women have been historically underrepresented in LVAD studies, and have been reported to have worse outcomes despite technological optimisation. We aimed to systematically explore the evidence on sex disparities in the use and outcomes of LVAD implantation.

METHODS

A systematic database search with meta-analysis was conducted of comparative original articles of men versus women undergoing LVAD implantation, in EMBASE, MEDLINE, Cochrane database and Google Scholar, from inception to July 2022. Primary outcomes were stroke (haemorrhagic and ischaemic) and early/overall mortality. Secondary outcomes were LVAD thrombosis, right VAD implantation, major bleeding, kidney dysfunction, and device/driveline infection.

RESULTS

Our search yielded 137 relevant studies, including 22 meeting the inclusion criteria with a total of 53 227 patients (24.2% women). Overall mortality was higher in women (odds ratio [OR] 1.35, 95% confidence interval [CI] 1.05-1.62, p = 0.02), as was overall stroke (OR 1.32, 95%CI 1.06-1.66, p = 0.01), including ischemic (OR 1.80, 95%CI 1.22-2.64, p = 0.003) and haemorrhagic (OR 1.72, 95%CI 1.09-2.70, p = 0.02). Women had more frequent right VAD implantation (OR 2.11, 95%CI 1.24-3.57, p = 0.006) and major bleeding (OR 1.40, 95%CI 1.06-1.85, p = 0.02). Kidney dysfunction, LVAD thrombosis, and device/driveline infections were comparable between sexes.

CONCLUSIONS

Our analysis suggests that women face a greater risk of adverse events and mortality post-LVAD implantation. Although the mechanisms remain unclear, the difference in outcomes is thought to be multifactorial. Further research, that includes comprehensive pre-operative characteristics and post-operative outcomes, is encouraged.

Special Considerations in the Care of Women With Advanced Heart Failure

Advanced heart failure (AHF) is associated with increased morbidity and mortality, and greater healthcare utilization. Recognition requires a thorough clinical assessment and appropriate risk stratification. There are persisting inequities in the allocation of AHF therapies. Women are less likely to be referred for evaluation of candidacy for heart transplantation or left ventricular assist device despite facing a higher risk of AHF-related mortality. Sex-specific risk factors influence progression to advanced disease and should be considered when evaluating women for advanced therapies. The purpose of this review is to discuss the role of sex hormones on the pathophysiology of AHF, describe the clinical presentation, diagnostic evaluation and definitive therapies of AHF in women with special attention to pregnancy, lactation, contraception and menopause. Future studies are needed to address areas of equipoise in the care of women with AHF.

Sex Differences in Recovery and Device Replacement After Left Ventricular Assist Device Implantation as Destination Therapy

Background The relevance of sex and preimplant factors for clinical outcomes among patients with left ventricular assist devices intended for destination therapy is unclear. Methods and Results INTERMACS (Interagency Registry for Mechanically Assisted Circulatory Support) data (2006-2017) from 6771 men and 1690 women with left ventricular assist devices as destination therapy were analyzed to evaluate the contribution of preimplant clinical, demographic, and clinically judged psychosocial characteristics to time until death, heart transplant, device explant due to recovery, or complication-related device replacement. Associations of sex with time until each competing outcome were evaluated using cumulative incidence functions and event-specific Cox proportional hazards models. Women were younger, more likely to have nonischemic diagnoses, and reported less substance abuse but were more likely to be unmarried, not working for an income, overweight, and depressed than men. After 2 years, women had higher probabilities for recovery (3.7% versus 1.6%, P<0.001) and device replacement (12.1% versus 10%, P=0.019) than men but not for death and transplant (P>0.12). The sex differences remained after controlling for covariates (adjusted hazard ratio [HR_adj] recovery, 1.85; 95% CI, 1.30-2.70; P<0.001; HR_adj device replacement, 1.22; 95% CI, 1.04-1.33; P=0.015). Female-specific diagnoses (eg, postpartum heart failure) contributed to women's enhanced rate of recovery. Demographic and psychosocial factors were unrelated to women's increased event rates. Conclusions In destination therapy, women have higher rates of device replacement and recovery than men. The latter was partly explained by female-specific diagnoses. Standardized assessments of psychosocial characteristics are needed to elucidate their association with sex differences in outcomes.

Sex Differences in Heart Failure

Heart failure (HF) continues to be a major contributor of morbidity and mortality for men and women alike, yet how the predisposition for, course and management of HF differ between men and women remains underexplored. Sex differences in traditional risk factors as well as sex-specific risk factors influence the prevalence and manifestation of HF in unique ways. The pathophysiology of HF differs between men and women and may explain sex-specific differences in clinical presentation and diagnosis. This in turn contributes to variation in response to both pharmacologic and device/surgical therapy. This review examines sex-specific differences in HF spanning prevalence, risk factors, pathophysiology, presentation, and therapies with a specific focus on highlighting gaps in knowledge with calls to action for future research efforts.

Creation and Validation of a Novel Sex-Specific Mortality Risk Score in LVAD Recipients

Background

Prior studies have shown that women have worse 3‐month survival after receiving a left ventricular assist device compared with men. Currently used prognostic scores, including the Heartmate II Risk Score, do not account for the increased residual risk in women. We used the IMACS (International Society for Heart and Lung Transplantation Mechanically Assisted Circulatory Support) registry to create and validate a sex‐specific risk score for early mortality in left ventricular assist device recipients.

Methods and Results

Adult patients with a continuous‐flow LVAD from the IMACS registry were randomly divided into a derivation cohort (DC; n=9113; 21% female) and a validation cohort (VC; n=6074; 21% female). The IMACS Risk Score was developed in the DC to predict 3‐month mortality, from preoperative candidate predictors selected using the Akaike information criterion, or significant sex × variable interaction. In the DC, age, cardiogenic shock at implantation, body mass index, blood urea nitrogen, bilirubin, hemoglobin, albumin, platelet count, left ventricular end‐diastolic diameter, tricuspid regurgitation, dialysis, and major infection before implantation were retained as significant predictors of 3‐month mortality. There was significant ischemic heart failure × sex and platelet count × sex interaction. For each quartile increase in IMACS risk score, men (odds ratio [OR], 1.86; 95% CI, 1.74–2.00; P<0.0001), and women (OR, 1.93; 95% CI, 1.47–2.59; P<0.0001) had higher odds of 3‐month mortality. The IMACS risk score represented a significant improvement over Heartmate II Risk Score (IMACS risk score area under the receiver operating characteristic curve: men: DC, 0.71; 95% CI, 0.69–0.73; VC, 0.69; 95% CI, 0.66–0.72; women: DC, 0.73; 95% CI, 0.70–0.77; VC, 0.71 [95% CI, 0.66–0.76; P<0.01 for improvement in receiver operating characteristic) and provided excellent risk calibration in both sexes. Removal of sex‐specific interaction terms resulted in significant loss of model fit.

Conclusions

A sex‐specific risk score provides excellent risk prediction in LVAD recipients.