Mechanical circulatory support for the failing heart: Continuous-flow left ventricular assist devices

Background: Heart transplantation remains the definitive therapy for patients with advanced heart failure; however, owing to limited donor organ availability and long wait times, continuous-flow left ventricular assist devices (LVADs) have become standard therapy. Methods: This review summarizes the history, progression, function, and basic management of LVADs. Additionally, we provide some clinical pearls and important caveats for managing this unique patient population. Results: Currently, the most common LVADs being implanted in the United States are second- and third-generation devices, the HeartMate II (Thoratec Corp., St. Jude Medical) and the HeartWare HVAD (HeartWare International, Inc.). A newer thirdgeneration pump, the HeartMate III (Thoratec Corp., St. Jude Medical), is designed to create an artificial pulse and is currently under investigation in the United States. Conclusion: LVAD use is promising, will continue to grow, and has become standard therapy for advanced heart failure as a bridge to recovery, as destination therapy, and as a bridge to transplantation

Percutaneous ventricular assist devices: A novel approach in the management of patients with acute cardiogenic shock

Background: Despite recent advances in the management of heart failure, cardiogenic shock remains a challenging and devastating condition with significant morbidity and mortality. Methods: We review currently available percutaneous mechanical circulatory support (MCS) devices and address each device’s characteristics, mechanism of action, specific clinical indications, and contraindications. Results: Four types of percutaneous MCS devices are currently available: the intraaortic balloon pump (IABP), Impella devices, the TandemHeart, and extracorporal membrane oxygenation (ECMO). IABPs provide less hemodynamic support compared to the Impella, TandemHeart, and ECMO devices. However, because of its ease of placement and relatively small access catheter size, the IABP remains the most commonly used MCS device for the treatment of cardiogenic shock. When full cardiopulmonary support is needed, ECMO is the best option. Conclusion: Temporary MCS has emerged as a therapeutic option in the management of patients with acute cardiogenic shock. However, clinician familiarity with the indications, limitations, and benefits of individual MCS devices and enhanced patient comfort with the placement are paramount to improve patient outcomes

Echocardiographic Parameters Associated with Clinical Heart Failure Due to Partial Left Ventricular Unloading in Patients with Continuous-Flow LVAD

Patients with continuous-flow LVAD may develop clinical heart failure (HF) due to partial LV unloading. We aimed to examine clinical and echocardiographic predictors of HF defined by symptoms/signs and invasive hemodynamics. Records of patients who received LVAD from 2008-12 in our center were reviewed. Patients with adverse events <30 days of implant were excluded. Those who had simultaneous echo and right heart catheterization (RHC) composed the comparison groups. HF was defined as a syndrome of symptoms/signs (e.g. dyspnea/fatigue and jugular venous distention/leg edema) requiring in- or out-patient augmentation of therapy (e.g. change in diuretics/LVAD pump speed) and confirmed by high wedge pressure (≥15 mmHg) on RHC. Of 140 patients who survived beyond 30 days post-LVAD, 11 (8%) had HF. Baseline pump speed (rpm) between subjects and controls: 9,091±466 vs 9,200±927. Patients with HF had higher echo-measured E/A ratio (2.0±1.1 vs 1.1±0.8, P=0.03) and right atrial pressure (RAP) (14.9±4.0 vs 5.0±1.3, P<0.001) compared to controls (no s/sx and normal wedge). No clinical characteristics including body mass index and hypertension were associated with HF (Table). Elevated E/A ratio and RAP, echo markers of diastolic dysfunction and high right-sided pressures, are associated with HF due to partial LV unloading in LVAD patients. These echo parameters may help guide diagnosis and appropriate management in this population. Echo parameters in LVAD patients with and without HFHF & PCWP ≥15 (N=11)No HF & PCWP <15 (N=13)P valueRAP (mmHg)14.9±4.05.0±1.3<0.001E/A2.0±1.11.1±0.80.03E/e’15.3±4.111.1±4.70.05E88.8±26.966.6±25.10.06LAVi (mL/m2)34.1±13.424.3±8.60.06TV PG (mmHg)27.6±7.621.5±5.20.07DT (ms)179.9±48.4194.5±66.90.5E/A=Early/late mitral inflow, E/e’=Mitral early peak velocity/annular velocity, DT=Mitral deceleration time, LAVi=Left atrial volume index, RAP=Right atrial pressure, TV PG=Tricuspid pressure gradien