Clinical Implications of Respiratory Failure in Patients Receiving Durable Left Ventricular Assist Devices for End-Stage Heart Failure

Outcome after left ventricular assist device exchange

OBJECTIVES

Left ventricular assist device (LVAD) therapy has evolved from a short-term bridge-to-transplant strategy into a long-term and often chronic therapy due to long waiting times for heart transplantation and application as destination therapy. Consequently, patients are at risk of developing complications necessitating LVAD exchange. The aim of this study is to assess patient outcomes after LVAD exchange.

METHODS

Patients who underwent LVAD exchange between January 2010 and December 2022 were included. Logistic and cox regression analyses were used to identify potential risk factors for short and long-term adverse events, respectively. Survival after exchange was assessed using Kaplan-Meier estimates.

RESULTS

Sixty-one patients underwent a total of 80 LVAD exchanges. Most frequently observed short-term complications were pulmonary infections (16.3%) and right heart failure (16.3%). Exit-site infections (34.7%) and device malfunctions (25.3%) were the most often observed long-term complications. HeartWare ventricular assist device as index device was associated with a higher risk of right heart failure [hazard ratio 6.42, 95% confidence interval (CI) 1.80-22.90] and respiratory failure (hazard ratio 7.81, 95% CI 1.95-31.23) compared to HeartMate II and HeartMate 3. Survival was 83% (95% CI 75.5-95.3%) at 1 year and 67% (95% CI 53.9-84.7%) at 6 years after exchange. After 5 years, 25.0% was transplanted, 23.8% had undergone a re-exchange and 32.5% was alive without new intervention.

CONCLUSIONS

Although LVAD exchange can be performed with a relatively low mortality, other post-operative adverse events are common. Patients with the HeartWare ventricular assist device as index device may be at higher risk of developing right heart failure and respiratory failure after exchange.

Long-term predictors of morbidity and mortality in patients following LVAD replacement

BACKGROUND

As heart transplant guidelines evolve, the clinical indication for 73% of durable left ventricular assist device (LVAD) implants is now destination therapy. Although completely magnetically levitated LVAD devices have demonstrated improved durability relative to previous models, LVAD replacement procedures are still required for a variety of indications. Thus, the population of patients with a replaced LVAD is growing. There is a paucity of data regarding the outcomes and risk factors for those patients receiving first-time LVAD replacements.

METHODS

The study cohort consisted of all consecutive patients between 2006 and 2020 that received a first-time LVAD replacement at a single institution. Preoperative clinical and laboratory variables were collected retrospectively. The primary endpoint was death or need for an additional LVAD replacement. Data were subjected to Kaplan-Meier, univariate, and multivariate Cox hazard ratio analyses.

RESULTS

In total, 152 patients were included in the study, of which 101 experienced the primary endpoint. On multivariate analysis, patients receiving HeartMate 3 (HM3) LVADs as the replacement device showed superior outcomes (HR 0.15, 95% CI 0.065-0.35, p < 0.0001). Independent risk factors for death or need for additional replacement included preoperative extracorporeal membrane oxygenation (ECMO) (HR 4.44, 95% CI 1.87-14.45, and p = 0.00042), increased number of sternotomies (HR 5.20, 95% CI 1.87-14.45, and p = 0.0016), and preoperative mechanical ventilation (HR 1.98, 95% CI 1.01-3.86, and p = 0.045).

CONCLUSIONS

Replacement with HM3 showed superior outcomes compared to all other pump types when controlling for both initial pump type and other independent predictors of death or LVAD replacement. Preoperative ECMO, mechanical ventilation, and multiple sternotomies also increased the odds for death or the need for subsequent replacement.

Clinical Predictors and Outcomes After Left Ventricular Assist Device Implantation and Tracheostomy

BACKGROUND

Postoperative respiratory failure is a major complication that affects up to 10% of patients who undergo cardiac surgery and has a high in-hospital mortality rate. Few studies have investigated whether patients who require tracheostomy for postoperative respiratory failure after continuous-flow left ventricular assist device (CF-LVAD) implantation have worse survival outcomes than patients who do not.

OBJECTIVE

To identify risk factors for respiratory failure necessitating tracheostomy in CF-LVAD recipients and to compare survival outcomes between those who did and did not require tracheostomy.

METHODS

Consecutive patients who underwent primary CF-LVAD placement at a single institution between August 1, 2002, and December 31, 2019, were retrospectively reviewed. Propensity score matching accounted for baseline differences between the tracheostomy and nontracheostomy groups. Multivariate logistic regression was used to identify tracheostomy risk factors and 90-day survival; Kaplan-Meier analysis was used to assess midterm survival.

RESULTS

During the study period, 664 patients received a CF-LVAD; 106 (16.0%) underwent tracheostomy for respiratory failure. Propensity score matching produced 103 matched tracheostomy-nontracheostomy pairs. Patients who underwent tracheostomy were older (mean [SD] age, 57.9 [12.3] vs 54.6 [13.9] years; P = .02) and more likely to need preoperative mechanical circulatory support (61.3% vs 47.8%; P = .01) and preoperative intubation (27.4% vs 8.8%; P < .001); serum creatinine was higher in the tracheostomy group (mean [SD], 1.7 [1.0] vs 1.4 [0.6] mg/dL; P < .001), correlating with tracheostomy need (odds ratio, 1.76; 95% CI, 1.21-2.56; P = .003). Both before and after propensity matching, 30-day, 60-day, 90-day, and 1-year survival were worse in patients who underwent tracheostomy. Median follow-up was 0.8 years (range, 0.0-11.2 years). Three-year Kaplan-Meier survival was significantly worse for the tracheostomy group before (22.0% vs 61.0%; P < .001) and after (22.4% vs 48.3%; P < .001) matching.

CONCLUSION

Given the substantially increased probability of death in patients who develop respiratory failure and need tracheostomy, those at high risk for respiratory failure should be carefully considered for CF-LVAD implantation. Comprehensive management to decrease respiratory failure before and after surgery is critical.

Relation of Ischemic Heart Disease to Outcomes in Patients With Acute Respiratory Distress Syndrome

Patients with ischemic heart disease (IHD) are often excluded from acute respiratory distress syndrome (ARDS) clinical trials. As a result, little is known about the impact of IHD in this population. We sought to assess the association between IHD and clinical outcomes in patients with ARDS. Participants from 4 ARDS randomized controlled trials with shared study criteria, definitions, and end points were included. Using multivariable logistic regression, we assessed for the association between IHD and a primary outcome of 60-day mortality. Secondary outcomes included 90-day mortality, 28-day ventilator-free days, and 28-day organ failure. Among 1,909 patients, 102 had a history of IHD (5.4%). Patients with IHD were more likely to be older and male (p <0.05). Noncardiac co-morbidities, severity of illness, and other markers of ARDS severity were not statistically different (all, p >0.05). Patients with IHD had a higher 60-day (39.2% vs 23.3%, p <0.001) and 90-day (40.2% vs 24.0%, p <0.001) mortality, and experienced more frequent renal (45.1% vs 32.0%, p = 0.006) and hepatic (35.3% vs 25.2%, p = 0.023) failure. After multivariable adjustment, 60-day (odds ratio [OR] 1.76; 95% confidence interval [CI]: 1.07 to 2.89, p = 0.025) and 90-day (OR 1.74; 95% CI: 1.06 to 2.85, p = 0.028) mortality remained higher. IHD was associated with 10% fewer ventilator-free days (incidence rate ratio 0.90; 95% CI: 0.85 to 0.96, p = 0.001). In conclusion, co-morbid IHD was associated with higher mortality and fewer ventilator-free days in patients with ARDS. Future studies are needed to identify predictors of mortality and improve treatment paradigms in this critically ill subgroup of patients.

Successful recovery with venovenous ECMO for ARDS after LVAD HeartMate 3 implantation: A case report

Acute respiratory distress syndrome (ARDS) following left ventricular assist device (LVAD) implantation is a rare complication. Venovenous (VV) extracorporeal membrane oxygenation (ECMO) is used as a treatment for severe ARDS and pneumonia. We report the successful use of VV ECMO for ARDS Klebsiella pneumonia following urgent LVAD HeartMate 3 implantation.

Mechanical ventilation at the time of heart transplantation and associations with clinical outcomes

AIMS

The impact of mechanical ventilation (MV) at the time of heart transplantation is not well understood. In addition, MV was recently removed as a criterion from the new US heart transplantation allocation system. We sought to assess for the association between MV at transplantation and 1-year mortality.

METHODS AND RESULTS

We utilized the United Network for Organ Sharing database and included all adult, single organ heart transplantations from 1990 to 2019. We utilized multivariable logistic regression adjusting for demographics, comorbidities, and markers of clinical acuity. We identified 60 980 patients who underwent heart transplantation, 2.4% (n = 1431) of which required MV at transplantation. Ventilated patients were more likely to require temporary mechanical support, previous dialysis, and had a shorter median waitlist time (21 vs. 95 days, P < 0.001). At 1 year, the mortality was 33.7% (n = 484) for ventilated patients and 11.7% (n = 6967) for those not ventilated at the time of transplantation (log-rank P < 0.001). After multivariable adjustment, patients requiring MV continued to have a substantially higher 90-day [odds ratio (OR) 3.20, 95% confidence interval (CI): 2.79-3.66, P < 0.001] and 1-year mortality (OR 2.67, 95% CI: 2.36-3.03, P < 0.001). For those that survived to 90 days, the adjusted mortality at 1 year continued to be higher (OR 1.48, 95% CI: 1.16-1.89, P = 0.002).

CONCLUSION

We found a strong association between the presence of MV at heart transplantation and 90-day and 1-year mortality. Future studies are needed to identify which patients requiring MV have reasonable outcomes, and which are associated with substantially poorer outcomes.

Outcomes in patients with anthracycline-induced cardiomyopathy undergoing left ventricular assist devices implantation

Aims

Improved cancer survivorship has led to a higher number of anthracycline‐induced cardiomyopathy patients with end‐stage heart failure. We hypothesize that outcomes following continuous‐flow LVAD (CF‐LVAD) implantation in those with anthracycline‐induced cardiomyopathy are comparable with other aetiologies of cardiomyopathy.

Methods and results

Using the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) from 2008 to 2017, we identified patients with anthracycline‐induced cardiomyopathy who received a CF‐LVAD and compared them with those with idiopathic dilated (IDM) and ischaemic cardiomyopathies (ICM). Mortality was studied using the Cox proportional hazards model. Other adverse events were evaluated using competing risk models. Overall, 248 anthracycline‐induced cardiomyopathy patients underwent CF‐LVAD implantation, with a median survival of 48 months, an improvement compared with those before 2012 [adjusted hazards ratio (aHR): 0.53; confidence interval (CI): 0.33–0.86]. At 12 months, 85.1% of anthracycline‐induced cardiomyopathy, 86.0% of IDM, and 80.2% of ICM patients were alive (anthracycline‐induced cardiomyopathy vs. IDM: aHR: 1.12; CI: 0.88–1.43 and anthracycline‐induced cardiomyopathy vs. ICM: aHR: 0.98; CI: 0.76–1.28). Anthracycline‐induced cardiomyopathy patients had a higher major bleeding risk compared with IDM patients (aHR: 1.23; CI: 1.01–1.50), and a lower risk of stroke and prolonged respiratory support compared to ICM patients (aHR: 0.31 and 0.67 respectively; both P < 0.05). There was no difference in the risk of major infection, acute kidney injury, and venous thromboembolism.

Conclusions

After receiving a CF‐LVAD, survival in patients with anthracycline‐induced cardiomyopathy is similar to those with ICM or IDM. Further research into differential secondary endpoints‐related disparities is warranted.

Prevalence of Noncardiac Multimorbidity in Patients Admitted to Two Cardiac Intensive Care Units and Their Association with Mortality

BACKGROUND

Current cardiac intensive care unit (CICU) practice has seen an increase in patient complexity, including an increase in noncardiac organ failure, critical care therapies, and comorbidities. We sought to describe the changing epidemiology of noncardiac multimorbidity in the CICU population.

METHODS

We analyzed consecutive unique patient admissions to 2 geographically distant tertiary care CICUs (n = 16,390). We assessed for the prevalence of 0, 1, 2, and ≥3 noncardiac comorbidities (diabetes, chronic lung, liver, and kidney disease, cancer, and stroke/transient ischemic attack) and their associations with hospital and postdischarge 1-year mortality using multivariable logistic regression.

RESULTS

The prevalence of 0, 1, 2, and ≥3 noncardiac comorbidities was 37.7%, 31.4%, 19.9%, and 11.0%, respectively. Increasing noncardiac comorbidities were associated with a stepwise increase in mortality, length of stay, noncardiac indications for ICU admission, and increased utilization of critical care therapies. After multivariable adjustment, compared with those without noncardiac comorbidities, there was an increased hospital mortality for patients with 1 (odds ratio [OR] 1.30; 95% confidence interval [CI], 1.10-1.54, P = .002), 2 (OR 1.47; 95% CI, 1.22-1.77, P < .001), and ≥3 (OR 1.79; 95% CI, 1.44-2.22, P < .001) noncardiac comorbidities. Similar trends for each additional noncardiac comorbidity were seen for postdischarge 1-year mortality (P < .001, all).

CONCLUSIONS

In 2 large contemporary CICU populations, we found that noncardiac multimorbidity was highly prevalent and a strong predictor of short- and long-term adverse clinical outcomes. Further study is needed to define the best care pathways for CICU patients with acute cardiac illness complicated by noncardiac multimorbidity.

Trends in Therapy and Outcomes Associated With Respiratory Failure in Patients Admitted to the Cardiac Intensive Care Unit

PURPOSE

To describe the epidemiology, outcomes, and temporal trends of respiratory failure in the cardiac intensive care unit (CICU).

MATERIALS AND METHODS

Retrospective cohort analysis of 2,986 unique Mayo Clinic CICU patients from 2007 to 2018 with respiratory failure. Temporal trends were analyzed, along with hospital and 1-year mortality. Multivariable logistic regression was used to determine adjusted hospital mortality trends.

RESULTS

The prevalence of respiratory failure in the CICU increased from 15% to 38% during the study period (P < 0.001 for trend). Among patients with respiratory failure, the utilization of invasive ventilation decreased and noninvasive ventilation modalities increased over time. Hospital mortality and 1-year mortality were 24% and 54%, respectively, with variation according to the type of respiratory support (highest among patients receiving invasive ventilation alone: 35% and 46%, respectively). Hospital mortality was highest among patients with concomitant cardiac arrest and/or shock (52% for patients with both). Hospital mortality decreased in the overall population from 35% to 25% (P < 0.001 for trend), but was unchanged among patients receiving positive-pressure ventilation.

CONCLUSIONS

The prevalence of respiratory failure in CICU more than doubled during the last decade. The use of noninvasive respiratory support increased, while overall mortality declined over time. Cardiac arrest and shock accounted for the majority of deaths. Further research is needed to optimize the outcomes of high-risk CICU patients with respiratory failure.

Advanced Respiratory Support in the Contemporary Cardiac ICU

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The medical complexity and critical care needs of patients admitted to cardiac ICUs are increasing, and prospective studies examining the underlying cardiac and noncardiac diagnoses, the management strategies, and the prognosis of cardiac ICU patients with respiratory failure are needed.

Sex Differences in Patients Receiving Left Ventricular Assist Devices for End-Stage Heart Failure

OBJECTIVES

This study sought to use INTERMACS (Interagency Registry for Mechanically Assisted Circulatory Support) results to evaluate sex differences in the use and clinical outcomes of left ventricular assist devices (LVAD).

BACKGROUND

Despite a similar incidence of heart failure in men and women, prior studies have highlighted potential underuse of LVADs in women, and studies of clinical outcomes have yielded conflicting results.

METHODS

Patients were enrolled from the INTERMACS study who underwent implantation of their first continuous-flow LVAD between 2008 and 2017, and survival analyses stratified by sex were conducted.

RESULTS

Among the 18,868 patients, 3,984 (21.1%) were women. At 1 year, women were less likely to undergo heart transplantation than men (17.9% vs. 20.0%, respectively; p = 0.003). After multivariable adjustments, women had a higher risk of death (hazard ratio [HR]: 1.15; 95% confidence interval [CI]: 1.07 to 1.23; p < 0.001) and were more likely to incur post-implantation adverse events, including rehospitalization, bleeding, stroke, and pump thrombosis or device malfunction. Although women younger than 50 years of age had an increased risk of death compared to men of the same age (HR: 1.34; 95% CI: 1.12 to 1.6), men and women 65 years of age and older had a similar risk of death (HR: 1.09; 95% CI: 0.95 to 1.24).

CONCLUSIONS

This study found that women had a higher risk of mortality and adverse events after LVAD. Only 1 in 5 LVADs were implanted in women, and women were less likely to receive a heart transplant than men. Further investigation is needed to understand the causes of adverse events and potential underuse of advanced treatment options in women.