Leo Simpson

Use of the Percutaneous Left Ventricular Assist Device in Patients with Severe Refractory Cardiogenic Shock as a Bridge to Long-term Left Ventricular Assist Device Implantation

BACKGROUND For patients with persistent cardiogenic shock refractory to intraaortic balloon pump (IABP) support, there are only limited means of resuscitation and bridging to surgical left ventricular assist device (LVAD) implantation. Extracorporeal membrane oxygenation and emergency surgical approaches have been attempted but are associated with significant morbidity and mortality. We evaluated the efficacy of a percutaneous left ventricular assist device (PVAD) as a bridge to LVAD implantation in patients in cardiogenic shock refractory to IABP and pressor support. METHODS Between May 2003 and April 2006, at our institution, 18 patients in severe refractory cardiogenic shock received a PVAD as a bridge to LVAD placement or orthotopic heart transplantation. Six patients had ischemic cardiomyopathy, and 12 had nonischemic cardiomyopathy. At the time of PVAD placement, 17 were receiving IABP support, and 10 were undergoing cardiopulmonary resuscitation. RESULTS The mean duration of PVAD support was 4.2 +/- 2.5 days. During this time, the cardiac index improved from 0.86 +/- 0.66 to 2.50 +/- 0.93 liters/min/m2 (p < 0.001), systolic blood pressure improved from 72 +/- 11 to 98 +/- 15 mm Hg (p = 0.001), and systemic mixed venous oxygenation improved from 37 +/- 7 to 62 +/- 6 mm Hg (p < 0.001). We terminated life support in 4 of the 18 patients before LVAD placement; 14 were successfully bridged to LVAD or heart transplantation. The mortality rate was 27% at 30 days and 33% at 6 months. There were no PVAD-associated deaths. CONCLUSION In patients with terminal hemodynamic collapse, PVAD support is an effective bridging therapy to LVAD and appears to be a viable alternative to other invasive methods of support.

Clinical outcomes after ventricular assist device implantation in adults with complex congenital heart disease

BACKGROUND There are minimal data regarding ventricular assist device (VAD) implantation in adult patients with complex congenital heart disease (CHD). METHODS The medical records of 6 adult patients with complex CHD who underwent VAD implantation were retrospectively analyzed to characterize pre-operative clinical status, implantation techniques and challenges, post-operative management, and post-operative outcomes. RESULTS All patients had a systemic right ventricle, including 2 with single-ventricle physiology. The average age at VAD implantation was 41 years. The implanted VADs included 1 HeartMate XVE, 3 HeartMate II (Thoratec Corp, Pleasanton, CA), 1 Jarvik 2000 (Jarvik Heart, New York, NY), and 1 HeartWare HVAD (HeartWare Inc, Framingham, MA). In-hospital outcomes included no sub-pulmonic ventricular failure, no VAD thrombosis or mechanical failure, 30-day mortality in 1 patient, non-fatal sub-arachnoid hemorrhage in 1 patient, and sustained ventricular tachycardia requiring unsynchronized direct current cardioversion in 1 patient. Of the 5 patients who survived to discharge, 1 patient received 171 days of VAD support before cardiac transplantation and survived for 1,484 days after transplantation; 1 patient received 262 days of VAD support before out-of-hospital death of unknown etiology; 1 patient had received VAD support for 988 days as of December 1, 2012, while awaiting a transplant; and 2 patients who received VADs as destination therapy had received 577 and 493 days of VAD support, respectively, and were still alive as of December 1, 2012. CONCLUSIONS This case series characterizes important post-operative management challenges and clinical outcomes associated with VAD implantation as a bridge-to-transplant or as destination therapy in adult patients with complex CHD.

Association between cell-derived microparticles and adverse events in patients with nonpulsatile left ventricular assist devices

BACKGROUND Continuous-flow left ventricular assist devices (LVADs) expose blood cells to high shear stress, potentially resulting in the production of microparticles that express phosphatidylserine (PS+) and promote coagulation and inflammation. In this prospective study, we attempted to determine whether PS+ microparticle levels correlate with clinical outcomes in LVAD-supported patients. METHODS We enrolled 20 patients undergoing implantation of the HeartMate II LVAD (Thoratec Corp, Pleasanton, CA) and 10 healthy controls who provided reference values for the microparticle assays. Plasma was collected before LVAD implantation, at discharge, at the 3-month follow-up, and when an adverse clinical event occurred. We quantified PS+ microparticles in the plasma using flow cytometry. RESULTS During the study period, 8 patients developed adverse clinical events: ventricular tachycardia storm in 1, non-ST-elevation myocardial infarction in 2, arterial thrombosis in 2, gastrointestinal bleeding in 2, and stroke in 3. Levels of PS+ microparticles were higher in patients at baseline than in healthy controls (2.11% ± 1.26% vs 0.69% ± 0.46%, p = 0.007). After LVAD implantation, patient PS+ microparticle levels increased to 2.39% ± 1.22% at discharge and then leveled to 1.97% ± 1.25% at the 3-month follow-up. Importantly, levels of PS+ microparticles were significantly higher in patients who developed an adverse event than in patients with no events (3.82% ± 1.17% vs 1.57% ± 0.59%, p < 0.001), even though the 2 patient groups did not markedly differ in other clinical and hematologic parameters. CONCLUSIONS Our results suggest that an elevation of PS+ microparticle levels may be associated with adverse clinical events. Thus, measuring PS+ microparticle levels in LVAD-supported patients may help identify patients at increased risk for adverse events.

Causes and management of drug-induced long QT syndrome.

Long QT syndrome (LQTS) is characterized by inherited or acquired prolonged QT interval on the surface electrocardiogram. This can lead to torsade de pointes ventricular tachycardia (TdP VT) and ventricular fibrillation. In the acquired form of the disease, medications from several classes can cause TdP VT or potentiate the electrocardiographic findings. These include class IA and III antiarrhythmics, antibiotics (macrolides and quinolones), antidepressants (tricyclics and selective serotonin reuptake inhibitors), antipsychotics (haloperidol and phenothiazines), and antiemetics (ondansetron and prochlorperazine). We present four cases of drug-induced LQTS resulting in life-threatening cardiac arrhythmias. Antiarrhythmic medications were the cause in two cases, and the other two cases involved noncardiac medications. All four patients had at least one risk factor for LQTS in addition to the offending drug, including female gender, hypokalemia, hypomagnesemia, and bradycardia. In one patient, amiodarone was administered for treatment of VT, although the correct diagnosis was actually TdP VT. In patients with polymorphic VT or ventricular fibrillation without a significant history of cardiovascular disease, drug-induced LQTS should be high in the differential diagnosis. Prompt diagnosis is key, as amiodarone, while often used to suppress VT, is potentially harmful in the setting of LQTS and TdP VT.

The State of the Art in Extracorporeal Membrane Oxygenation

Extracorporeal membrane oxygenation has evolved in design, technology, patient selection, insertion techniques, adjunct devices, and management in the past 45 years since it began. Outcomes have improved and indications have expanded. It continues to be an expeditious, cost-effective tool for rapid resuscitation of patients with cardiorespiratory failure, whose outcomes without extracorporeal membrane oxygenation intervention are predominately fatal. However, results are still moderately satisfactory, and the ethical aspects of ongoing care need to be at the forefront of daily family discussions in patients for whom a bridge to transplant or definitive device is not possible.

Unusual origin of type 1 atrioventricular block with comments on Wenckebach's contribution

We present a case that demonstrates the rare occurrence of type 1 second-degree atrioventricular block (Wenckebach or Mobitz type 1 block) as a result of block in the infranodal conduction system. This extremely rare occurrence often predicts progression to complete heart block and necessitates cardiac pacing. It also demonstrates the value of an electrophysiological study and exercise stress testing to identify the level of block, predict prognosis, and plan a management strategy.

Improved Systemic Saturation after Ventricular Assist Device Implantation in a Patient with Decompensated Dextro-Transposition of the Great Arteries after the Fontan Procedure

We report the successful implantation of a HeartMate II left ventricular assist device after a failed Fontan procedure in a patient with dextro-transposition of the great arteries. The patient had developed significant intrapulmonary arteriovenous shunting. Despite the theoretical risk of worsening intrapulmonary shunting due to the decrease in systemic vascular resistance after device implantation, our patient did well. He was discharged from the hospital in stable condition and had better oxygen saturation than before the device was implanted. To our knowledge, ours is the 2nd report of the use of a ventricular assist device after the failure of a Fontan procedure, and the first report concerning the effect of ventricular assist device implantation on intrapulmonary shunting.

Percutaneous Ventricular Assist Device in Hypertrophic Obstructive Cardiomyopathy With Cardiogenic Shock: Bridge to Myectomy

We present the case of a 69-year-old woman with end-stage hypertrophic obstructive cardiomyopathy who developed cardiogenic shock. She underwent emergent placement of a percutaneous left ventricular assist device (TandemHeart) in the catheterization lab as a bridge support device until a septal myectomy could be performed as definitive treatment. This case suggests a novel and promising use of the TandemHeart as a bridge to myectomy.

Percutaneous Interventions in Adults with Complex Cyanotic Congenital Heart Disease

BACKGROUND Adult patients with complex cyanotic heart disease present unique anatomic and physiological challenges. Changes in pulmonary blood flow over time may cause progressive cyanosis and exercise intolerance. The utility of percutaneous intervention in palliating adults with complex anatomy is unknown. METHODS This is a single-center case series of percutaneous interventions in adults with complex cyanotic heart disease. Six patients (5 males, 1 female) underwent a total of 9 percutaneous interventions. Three patients required a second intervention 2, 10, and 13 months after the first intervention. Patients were followed a mean of 35 months after the first intervention. RESULTS Eight interventions were performed for diminished pulmonary blood flow and 1 intervention was performed for excessive pulmonary blood flow. Age at first intervention ranged from 28 to 48 years. Procedural success rate was 100%. There were no procedure-related complications. Mean oxygen saturation increased from 77% prior to the procedure to 86% after the intervention. All patients experienced symptomatic improvement. There was 1 late sudden death 17 months post procedure. CONCLUSIONS Percutaneous intervention can be performed safely and improves symptoms and oxygenation in adults with complex cyanotic heart disease.

Acute kidney injury after implantation of a left ventricular assist device: a comparison of axial-flow (HeartMate II) and centrifugal-flow (HeartWare HVAD) devices

Continuous-flow left ventricular assist devices (CF-LVADs) are increasingly being used to treat advanced, refractory chronic heart failure. Herein, we sought to determine the incidence of postoperative acute kidney injury (AKI) in axial-flow (HeartMate II; HM-II) and centrifugal-flow (HVAD) CF-LVAD recipients, as well as the effect of AKI on mortality. The study cohort comprised 520 patients who received a HM-II (n = 398) or HVAD (n = 122) at our center between November 2003 and March 2016. Their records were reviewed to determine the incidence of RIFLE-defined AKI after LVAD implantation. We compared the perioperative characteristics, postoperative complications, and survival rates of the patients with and without AKI and differentiated the outcomes based on device type (HM-II or HVAD). Seventy-five patients (14.4%) developed AKI postoperatively. Patients with AKI after LVAD implantation had significantly reduced survival compared to patients without AKI (p = 0.01). Cox proportional hazards models showed that AKI was a significant independent predictor of mortality (HR = 1.54, p = 0.03). Preoperative mechanical circulatory support and prolonged cardiopulmonary bypass time were independent predictors of AKI. The incidence of AKI was similar for HM-II and HVAD recipients (p = 0.25). There was no significant difference in AKI rates for the HM-II and HVAD recipients. Developing AKI adversely affected survival.