L. Truby

Clinical outcome of mechanical circulatory support for refractory cardiogenic shock in the current era

BACKGROUND Mortality for refractory cardiogenic shock (RCS) remains high. However, with improving mechanical circulatory support device (MCSD) technology, the treatment options for RCS patients are expanding. We report on a recent 5-year single-center experience with MCSD for treatment of RCS. METHODS This study was a retrospective review of adult patients who required an MCSD due to RCS in the past 5 years. We excluded those patients with post-cardiotomy shock and post-transplant cardiac graft dysfunction. In the setting of RCS, a short-term ventricular assist device (VAD) was inserted as a bridge-to-decision device. Veno-arterial extracorporeal membrane oxygenation (VA ECMO) was chosen in cases of unknown neurologic status, complete hemodynamic collapse or severe coagulopathy. RESULTS From January 2007 through January 2012, 90 patients received an MCSD for RCS, 21 (23%) of whom had active cardiopulmonary resuscitation (CPR). The etiology of RCS included acute myocardial infarction in 49% and acute decompensated heart failure in 27%. Mean age was 53±14 years, 71% were male, and 60% had an intra-aortic balloon pump. The initial approach utilized was short-term VAD in 49% and VA ECMO in 51%. Median length of support was 8 days (IQR 4 to 18 days). Exchange to implantable VAD was performed in 26% of patients. Other destinations included myocardial recovery in 18% and heart transplantation in 11%. Survival to hospital discharge was 49%. Multivariate analysis showed ongoing CPR to be an independent risk factor for mortality (OR = 5.79, 95% CI 1.285 to 26.08, p = 0.022). CONCLUSIONS In the current era, roughly half of the patients who need an MCSD for RCS survive, and roughly half of these survivors require an implantable VAD. Ongoing CPR is predictive of in-hospital mortality.

Bridge-to-Decision Therapy With a Continuous-Flow External Ventricular Assist Device in Refractory Cardiogenic Shock of Various Causes

Background—Mortality for refractory cardiogenic shock remains high. In this patient cohort, there have been mixed results in mechanical circulatory support device use as a bridge-to-decision therapy. We evaluated a continuous-flow external ventricular assist device (VAD), CentriMag VAD (Thoratec Corp., Pleasanton, CA), in patients with various causes of refractory cardiogenic shock. Methods and Results—This is a retrospective review of adult patients who underwent surgical CentriMag VAD insertion as bridge-to-decision therapy. From January 2007 through June 2012, 143 patients received CentriMag VAD. The cause of refractory cardiogenic shock was failure of medical management in 71 patients, postcardiotomy shock in 37, graft failure post–heart transplantation in 22, and right ventricular failure post–implantable left VAD in 13. Mean age was 52±16 years, and 71% were in INTERMACS (Interagency Registry for Mechanically Assisted Circulatory Support) profile 1. Among 158 device runs, device configuration was BiVAD in 67%, isolated right VAD in 26%, and isolated left VAD in 8%. Median duration of support was 14 days (interquartile range, 8–26). Survival was 69% at 30 days and 49% at 1 year. The next destination after the CentriMag VAD was myocardial recovery in 30%, device exchange to an implantable VAD in 15%, and heart transplantation in 18%. The failure of medical management and the graft failure post–heart transplantation groups had higher 30-day survival compared with the postcardiotomy shock group. Major bleeding events occurred in 33% and cerebrovascular accidents in 14%. There was no CentriMag pump failure or thrombosis. Conclusions—Bridge-to-decision therapy with CentriMag VAD is feasible in a variety of refractory cardiogenic shock settings. Patients with postcardiotomy shock have inferior survival.

Contemporary Outcomes of Venoarterial Extracorporeal Membrane Oxygenation for Refractory Cardiogenic Shock at a Large Tertiary Care Center.

Refractory cardiogenic shock (RCS) is associated with significant morbidity and mortality, and current mainstays of medical therapy appear inadequate. Venoarterial extracorporeal membrane oxygenation (VA-ECMO) represents an increasingly accepted therapy for RCS. Demographics, past medical history, preoperative characteristics, outcomes, and adverse events were collected for consecutive patients who received VA-ECMO support for RCS at our institution from March 2007 to December 2013. One hundred and seventy-nine patients with a mean age of 56.9 ± 16.1 years were included. Etiologies of RCS included postcardiotomy shock in 70 patients (39%), acute myocardial infarction in 46 patients (26%), primary graft failure in 17 patients (10%), and acute decompensated heart failure in 24 patients (13%). Mean arterial pressure before VA-ECMO support was 59.4 ± 22.8 mm Hg and 30.7% (n = 55) were undergoing active cardiopulmonary resuscitation at the time of cannulation. Overall, 38.6% of patients (n = 69) survived to discharge and 44.7% of patients (n = 80) survived to 30 days. Myocardial recovery was achieved in 79.7% of survivors (n = 55) and 39.1% were transitioned to a more durable device. Univariate analysis identified age (p = 0.002) and etiology of RCS (p = 0.041) as the most significant predictors of in-hospital mortality. Venoarterial extracorporeal membrane oxygenation for RCS appears successful as salvage therapy. Age and etiology should be considered when evaluating patients for VA-ECMO.

Important role of mechanical circulatory support in acute myocardial infarction complicated by cardiogenic shock

OBJECTIVES Acute myocardial infarction (AMI) complicated by cardiogenic shock (CS) remains associated with significant mortality despite the widespread application of early revascularization strategies. Recent evidence suggests that the use of intra-aortic balloon pump (IABP) counterpulsation does not improve mortality in this cohort of patients. We summarize our experience with mechanical circulatory support (MCS) therapy for AMI/CS. METHODS This is a retrospective review of 61 patients who received MCS therapy for AMI/CS at our institution between March 2007 and March 2013. RESULTS Mean age was 60.2 ± 10.3 years; mean ejection fraction was 24 ± 15% and 29% of patients were receiving active cardiopulmonary resuscitation at the time of support initiation. Prior to the initiation of MCS, 70.5% of patients had an IABP. Mean arterial pressure improved significantly with MCS (63 mmHg prior to MCS, 82 mmHg after MCS, P ≤ 0.01). Mean length of support was 9.5 ± 11.0 days, and overall survival to 30 days was 59.0%. Among 30-day survivors, 44.4% required device exchange to a durable MCS device. Ultimately, only 31% (52.8% of patients who survived to 30 days) achieved myocardial recovery. CONCLUSIONS Short-term MCS therapy with subsequent aggressive use of durable MCS device may improve the unacceptably high mortality rate in AMI/CS. Rigorous prospective studies of MCS therapy in AMI/CS are warranted.

Incidence and Implications of Left Ventricular Distention During Venoarterial Extracorporeal Membrane Oxygenation Support

Left ventricular distention (LVD) during venoarterial extracorporeal membrane oxygenation (VA-ECMO) support is increasingly recognized but seldom reported in the literature. The current study defined LVD as not present (LVD−); subclinical (LVD+, evidence of pulmonary edema on chest radiograph AND pulmonary artery diastolic blood pressure greater than 25 mm Hg within the first 2 hours of intensive care unit admission); or clinical (LVD++, need for decompression of the left ventricle immediately following VA-ECMO initiation). Among 226 VA-ECMO device runs, 121 had sufficient data to define LVD retrospectively. Nine patients (7%) developed LVD++ requiring immediate decompression, and 27 patients (22%) met the definition of LVD+. Survival to discharge was similar among groups (LVD++: 44%, LVD+: 41%, LVD−: 44%). However, myocardial recovery appeared inversely related to the degree of LVD (LVD++: 11%, LVD+: 26%, LVD−: 40%). When death or transition to device was considered as a composite outcome, event-free survival was diminished in LVD++ and LVD+ patients compared with LVD−. Multivariable analysis identified cannulation of VA-ECMO during extracorporeal cardiopulmonary resuscitation (ECPR) as a risk factor for decompression (odds ratio [OR]: 3.64, confidence interval [CI]: 1.21–10.98; p = 0.022). Using a novel definition of LVD, the severity LVD was inversely related to the likelihood of myocardial recovery. Survival did not differ between groups. Extracorporeal cardiopulmonary resuscitation was associated with need for mechanical intervention.

Dose-dependent association between amiodarone and severe primary graft dysfunction in orthotopic heart transplantation

BACKGROUND There is growing concern regarding the association between pre-transplant amiodarone exposure and post-transplant adverse outcomes. We hypothesized that amiodarone use would be associated with the development of severe primary graft dysfunction (PGD) in a dose-dependent manner. METHODS This was a retrospective review of 269 adult orthotopic heart transplantation (OHT) recipients at our institution between 2010 and 2014. At the time of OHT, 100 were receiving amiodarone therapy (Group 1) and 169 were not (Group 2). RESULTS Pre-OHT creatinine was higher in Group 1 (1.49 ± 0.63 vs 1.27 ± 0.68 mg/dl, p = 0.011). At time of listing, Group 1 had higher frequency of status 2 (42.0% vs 29.0%), and Group 2 had higher frequency of status 1A (20.7% vs 8.0%; p = 0.009). Severe PGD (mechanical circulatory support within 24 hours post-OHT) was significantly higher in Group 1 (20.0% vs 5.3%, p < 0.001). Pre-OHT amiodarone use was an independent risk factor for severe PGD (odds ratio [OR], 6.05; 95% confidence interval [CI], 2.47-14.83; p < 0.001) and in-hospital mortality (OR, 2.88; 95% CI, 1.05-7.88; p = 0.039) in multivariable analysis. Each 100-mg increase in the day-of-OHT amiodarone dose (OR, 1.55; 95% CI, 1.26-1.90) and each 18,300-mg increase in the 6-month cumulative dose (OR, 1.67; 95% CI, 1.31-2.15) was associated with increased odds of developing severe PGD (p < 0.001 for both). CONCLUSIONS Amiodarone use pre-OHT is independently associated with increased incidence of severe PGD and in-hospital mortality and linearly associated with increased incidence of severe PGD in a dose-dependent manner.

Durability and clinical impact of tricuspid valve procedures in patients receiving a continuous-flow left ventricular assist device

OBJECTIVE Patients evaluated for a continuous-flow left ventricular assist device frequently present with severe right ventricular dysfunction with tricuspid regurgitation. Long-term outcomes of concurrent tricuspid valve procedures in continuous-flow left ventricular assist device implantation are unclear. METHODS From May 2004 to December 2013, 336 patients received continuous-flow left ventricular assist devices. Among these, 8 patients with prior tricuspid valve procedures were excluded. At continuous-flow left ventricular assist device implantation, 76 patients underwent tricuspid valve procedures (group A), including 68 repairs and 8 replacements. The remaining 252 patients did not receive concurrent tricuspid valve procedures (group B). RESULTS Preoperatively, group A had higher central venous pressure/pulmonary capillary wedge pressure (P = .032), total bilirubin (P = .009), and percentage of moderate or greater tricuspid regurgitation (98.7% vs 18.8%; P < .001). In group A, cardiopulmonary bypass time (136 ± 52.0 minutes vs 83.9 ± 38.8 minutes; P < .001), intraoperative platelet use (13.6 ± 6.70 units vs 11.7 ± 5.92 units; P = .042), and bleeding requiring reoperation (27.5% vs 16.7%; P = .046) were significantly increased. In-hospital mortality was similar (10.5% vs 6.4%; P = .22). On-device 2-year survival was 73.9% in group A and 74.2% in group B (P = .24). At 2 years, mean cumulative readmissions for right heart failure was 0.21 in group A and 0.27 in group B (P = .95). A generalized linear mixed-effects model showed that tricuspid valve procedures are protective for developing future significant tricuspid regurgitation (odds ratio, 0.38; 95% confidence interval, 0.19-0.76; P = .006). CONCLUSIONS Concomitant tricuspid valve procedures at continuous-flow left ventricular assist device implantation can be performed safely and are protective against worsening tricuspid regurgitation during the first 2 years of support.

Importance of stratifying acute kidney injury in cardiogenic shock resuscitated with mechanical circulatory support therapy

Objective: Although the outcomes of patients with cardiogenic shock remain poor, short‐term mechanical circulatory support has become an increasingly popular modality for hemodynamic assistance and organ preservation. Because the kidney is exquisitely sensitive to poor perfusion, acute kidney injury is a common sequela of cardiogenic shock. This study examines the incidence and clinical impact of acute kidney injury in patients with short‐term mechanical circulatory support for cardiogenic shock. Methods: Retrospective review was performed of 293 consecutive patients with cardiogenic shock who were treated with short‐term mechanical circulatory support. The well‐validated 2014 Kidney Disease Improving Global Outcomes criteria were used to stage acute kidney injury. Outcomes of interest were long‐term mortality and renal recovery. Results: Acute kidney injury developed in 177 of 293 patients (60.4%), of whom 113 (38.6%) were classified with stage 3 (severe). Kaplan–Meier survival estimates indicated a 1‐year survival of 49.2% in the nonsevere (stages 0‐2) acute kidney injury cohort versus 27.3% in the severe acute kidney injury cohort (P < .001). Multivariable Cox regression demonstrated that severe acute kidney injury was a predictor of long‐term mortality (hazard ratio, 1.54; confidence interval, 1.10‐2.14; P = .011). Among hospital survivors, renal recovery occurred more frequently (82.4% vs 63.2%, P = .069) and more quickly (5.6 vs 24.5 days, P < .0001) in the nonsevere than in the severe acute kidney injury group. Conclusions: Acute kidney injury is common and frequently severe in patients in cardiogenic shock treated with short‐term mechanical circulatory support. Milder acute kidney injury resolves with survival comparable to patients without acute kidney injury. Severe acute kidney injury is an independent predictor of long‐term mortality. Nonetheless, many surviving patients with acute kidney injury do experience gradual renal recovery.

Mechanical Circulatory Support Device Utilization and Heart Transplant Waitlist Outcomes in Patients With Restrictive and Hypertrophic Cardiomyopathy

Background: Patients with restrictive cardiomyopathy (RCM) and hypertrophic cardiomyopathy (HCM) generally are considered poor candidates for mechanical circulatory support devices (MCSDs) and often not able to be bridged mechanically to heart transplantation. This study characterized MCSD utilization and transplant waitlist outcomes in patients with RCM/HCM under the current allocation system and discusses changes in the era of the new donor allocation system. Methods and Results: Patients waitlisted from 2006 to 2016 in the United Network for Organ Sharing registry were stratified by RCM/HCM versus other diagnoses. MCSD utilization and waitlist duration were analyzed by propensity score models. Waitlist outcomes were assessed by cumulative incidence functions with competing events. Predictors of waitlist mortality or delisting for worsening status in patients with RCM/HCM were identified by proportional hazards model. Of 30 608 patients on the waitlist, 5.1% had RCM/HCM. Patients with RCM/HCM had 31 fewer waitlist days (P<0.01) and were ≈26% less likely to receive MCSD (P<0.01). Cumulative incidence of waitlist mortality was similar between cohorts; however, patients with RCM/HCM had higher incidence of heart transplantation. Predictors of waitlist mortality or delisting for worsening status in patients with RCM/HCM without MCSD support included estimated glomerular filtration rate <60 mL/min per 1.73 m2, pulmonary capillary wedge pressure >20 mm Hg, inotrope use, and subjective frailty. Conclusions: Patients with RCM/HCM are less likely to receive MCSD but have similar waitlist mortality and slightly higher incidence of transplantation compared with other patients. The United Network for Organ Sharing RCM/HCM risk model can help identify patients who are at high risk for clinical deterioration and in need of expedited heart transplantation.

Ventricular Assist Device Utilization in Heart Transplant Candidates: Nationwide Variability and Impact on Waitlist Outcomes

Background: Continuous-flow left ventricular assist devices (CF-LVADs) have become a standard treatment choice in advanced heart failure patients. We hypothesized that practice patterns with regards to CF-LVAD utilization vary significantly among transplant centers and impact waitlist outcomes. Methods and Results: The United Network for Organ Sharing registry was queried to identify adult patients who were waitlisted for heart transplantation (HT) between 2008 and 2015. Each patient was assigned a propensity score based on likelihood of receiving a durable CF-LVAD before or while waitlisted. The primary outcomes of interest were death or delisting for worsening status and HT at 1 year. A total of 22 863 patients from 92 centers were identified. Among these, 9013 (39.4%) were mechanically supported. CF-LVAD utilization varied significantly between and within United Network for Organ Sharing regions. Freedom from waitlist death or delisting was significantly lower in propensity-score–matched patients who were mechanically supported versus medically managed (83.5% versus 79.2%; P<0.001). However, cumulative incidence of HT was also lower in mechanically supported patients (53.3% versus 63.6%; P<0.001). Congruous mechanical and medical bridging strategies based on clinical risk profile were associated with lower risk of death or delisting (hazard ratio, 0.88; P=0.027) and higher likelihood of HT (hazard ratio, 1.14; P<0.001). Conclusions: CF-LVAD utilization may lower waitlist mortality at the expense of lower likelihood of HT. Decision to use CF-LVAD and timing of transition should be individualized based on patient-, center-, and region-level risk factors to achieve optimal outcomes.