William L. Holman

Berlin Heart EXCOR Pediatric Ventricular Assist Device for Bridge to Heart Transplantation in US Children

Background— Recent data suggest that the Berlin Heart EXCOR Pediatric ventricular assist device is superior to extracorporeal membrane oxygenation for bridge to heart transplantation. Published data are limited to 1 in 4 children who received the device as part of the US clinical trial. We analyzed outcomes for all US children who received the EXCOR to characterize device outcomes in an unselected cohort and to identify risk factors for mortality to facilitate patient selection. Methods and Results— This multicenter, prospective cohort study involved all children implanted with the Berlin Heart EXCOR Pediatric ventricular assist device at 47 centers from May 2007 through December 2010. Multiphase nonproportional hazards modeling was used to identify risk factors for early (<2 months) and late mortality. Of 204 children supported with the EXCOR, the median duration of support was 40 days (range, 1–435 days). Survival at 12 months was 75%, including 64% who reached transplantation, 6% who recovered, and 5% who were alive on the device. Multivariable analysis identified lower weight, biventricular assist device support, and elevated bilirubin as risk factors for early mortality and bilirubin extremes and renal dysfunction as risk factors for late mortality. Neurological dysfunction occurred in 29% and was the leading cause of death. Conclusions— Use of the Berlin Heart EXCOR has risen dramatically over the past decade. The EXCOR has emerged as a new treatment standard in the United States for pediatric bridge to transplantation. Three-quarters of children survived to transplantation or recovery; an important fraction experienced neurological dysfunction. Smaller patient size, renal dysfunction, hepatic dysfunction, and biventricular assist device use were associated with mortality, whereas extracorporeal membrane oxygenation before implantation and congenital heart disease were not.

Preoperative and postoperative comparison of patients with univentricular and biventricular support with the thoratec ventricular assist device as a bridge to cardiac transplantation

OBJECTIVES The goal of this study was to determine whether there are differences in populations of patients with heart failure who require univentricular or biventricular circulatory support. METHODS Two hundred thirteen patients who were in imminent risk of dying before donor heart procurement and who received Thoratec left (LVAD) and right (RVAD) ventricular assist devices at 35 hospitals were divided into three groups: group 1 (n = 74), patients adequately supported with isolated LVADs; group 2 (n = 37), patients initially receiving an LVAD and later requiring an RVAD; and group 3 (n = 102), patients who received biventricular assistance (BiVAD) from the beginning. RESULTS There were no significant differences in any preoperative factors between the two BiVAD groups. In the combined BiVAD groups, pre-VAD cardiac index (BiVAD, 1.4 +/- 0.6 L/min per square meter, vs LVAD, 1.6 +/- 0.6 L/min per square meter) and pulmonary capillary wedge pressure (BiVAD, 27 +/- 8 mm Hg, vs LVAD, 30 +/- 8 mm Hg) were significantly lower than those in the LVAD group, and pre-VAD creatinine levels were significantly higher (BiVAD, 1.9 +/- 1.1 mg/dl, vs LVAD, 1.4 +/- 0.6 mg/dl). In addition, greater proportions of patients in the BiVAD groups required mechanical ventilation before VAD placement (60% vs 35%) and were implanted under emergency conditions than in the LVAD group (22% vs 9%). The survival of patients through heart transplantation was significantly better in patients who had an LVAD (74%) than in those who had BiVADs (58%). However, there were no significant differences in posttransplantation survival through hospital discharge (LVAD, 89%; BiVAD, 81%). CONCLUSION Patients who received LVADs were less severely ill before the operation and consequently were more likely to survive after the operation. As the severity of illness increases, patients are more likely to require biventricular support.

Usefulness of transesophageal echocardiography in assessment of aortic dissection.

Background The value of transesophageal echocardiography in the assessment of patients with aortic dissection was studied. Methods and Results Group 1 (34 patients) represented all patients studied at our institution with this technique in whom aortic dissection was proven by aortography, surgery, or autopsy. Group 2 (27 patients) represented all patients studied with this technique at our institution in whom aortic dissection was excluded by aortography. Transesophageal echocardiography made a correct diagnosis of aortic dissection in 33 of 34 patients (sensitivity, 97%; specificity, 100%). It also correctly demonstrated the type of dissection in all 29 patients with aortographic or surgical proof. On the other hand, computed tomography scanning, performed in 24 of 34 patients in group 1, made a correct diagnosis in only 67% of patients and misclassified the type of dissection in 33%. Transesophageal echocardiography correctly identified involvement of the coronary arteries by aortic dissection in six of seven patients as well as absence of both left and right coronary artery involvement in 10 patients with aortic dissection. This technique was also useful in detecting communications between the true and false lumens, presence of thrombi in the false lumen, and, in two patients, localized dissection rupture with formation of a false aneurysm. In both groups 1 and 2, transesophageal echocardiography correctly identified patients with moderate to aortic regurgitation. Conclusions Transesophageal echocardiography is very useful in the assessment of aortic dissection.

Predictors of Death and Transplant in Patients With a Mechanical Circulatory Support Device: A Multi-institutional Study

BACKGROUND INTERMACS is a registry of FDA-approved durable mechanical circulatory support (MCS) devices used for the strategies of destination therapy (DT) and bridge to transplantation (BTT) or recovery. This study identifies predictors for death and transplantation based on initial results from INTERMACS. METHODS From June 23, 2006 to December 31, 2007, 420 patients from 75 institutions were prospectively entered into the INTERMACS database in which pre-implant data, indication for MCS device use, adverse events, demographics, hemodynamics, laboratory values and outcomes were recorded. Using competing outcomes methodology, risk factors were identified for the events of death and transplantation. RESULTS The devices included 314 left ventricular assist devices (LVADs), 5 right VADs (RVADs), 77 biventricular VADs (biVADs) and 24 total artificial hearts (TAHs) for a total of 497 pumps in 420 patients. Among the BTT patients at 6 months, 33% were alive with a device in place, 42% were transplanted, 22% had died, and 3% were explanted for recovery. Among the DT patients at 6 months, 68% were alive with a device in place, 5% were transplanted, 25% had died, and 2% were explanted for recovery. The risk factors identified for death across all patient groups include older age (relative risk [RR] = 1.41, p < 0.001), ascites (RR = 2.04, p = 0.003), increased bilirubin (RR = 1.49, p < 0.05) and INTERMACS Level 1 (cardiogenic shock) (RR = 1.59, p = 0.02). The most common causes of death were central nervous system (CNS) event (18.3% of deaths), multiple-organ failure (16.4%) and cardiac cause (right ventricular failure and arrhythmias, 15.4%). CONCLUSIONS Cardiogenic shock, advanced age and severe right heart failure manifested as ascites or increased bilirubin are risk factors for death after MCS therapy. BTT patients who require biVAD support have a transplant rate similar to that of LVAD-only patients, but their mortality at 6 and 12 months exceeds that of LVAD-only patients. Consideration should be given to MCS referral before the sequelae of right ventricular failure dominate the advanced heart failure syndrome.

Radial Artery Grafts vs Saphenous Vein Grafts in Coronary Artery Bypass Surgery: A Randomized Trial

CONTEXT Arterial grafts are thought to be better conduits than saphenous vein grafts for coronary artery bypass grafting (CABG) based on experience with using the left internal mammary artery to bypass the left anterior descending coronary artery. The efficacy of the radial artery graft is less clear. OBJECTIVE To compare 1-year angiographic patency of radial artery grafts vs saphenous vein grafts in patients undergoing elective CABG. DESIGN, SETTING, AND PARTICIPANTS Multicenter, randomized controlled trial conducted from February 2003 to February 2009 at 11 Veterans Affairs medical centers among 757 participants (99% men) undergoing first-time elective CABG. INTERVENTIONS The left internal mammary artery was used to preferentially graft the left anterior descending coronary artery whenever possible; the best remaining recipient vessel was randomized to radial artery vs saphenous vein graft. MAIN OUTCOME MEASURES The primary end point was angiographic graft patency at 1 year after CABG. Secondary end points included angiographic graft patency at 1 week after CABG, myocardial infarction, stroke, repeat revascularization, and death. RESULTS Analysis included 733 patients (366 in the radial artery group, 367 in the saphenous vein group). There was no significant difference in study graft patency at 1 year after CABG (radial artery, 238/266; 89%; 95% confidence interval [CI], 86%-93%; saphenous vein, 239/269; 89%; 95% CI, 85%-93%; adjusted OR, 0.99; 95% CI, 0.56-1.74; P = .98). There were no significant differences in the secondary end points. CONCLUSION Among Veterans Affairs patients undergoing first-time elective CABG, the use of a radial artery graft compared with saphenous vein graft did not result in greater 1-year patency. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00054847.

Working formulation for the standardization of definitions of infections in patients using ventricular assist devices

In 2009, the International Society for Heart and Lung Transplantation (ISHLT) recognized the importance of infectionrelated morbidity and mortality in patients using ventricular assist devices (VADs) and the growing need for a consensusbased expert opinion to provide standard definitions of infections in these patients. The aim of these standard definitions is to improve clinical-investigator communication, allowing meaningful comparison in practice and outcomes between different centers and different VAD devices. In 2010, a core group of experts, including infectious diseases specialists, cardiologists, pathologists, radiologists, and cardiothoracic surgeons, formed an ISHLT Infectious Diseases Working Group to develop agreed criteria for definitions of infections in VAD patients. These definitions have been created by adapting and expanding on existing standardized definitions, which are based on the pathophysiology of equivalent infectious processes in prosthetic devices, such as cardiac prosthetic valve infections, intravascular catheter-related infections, and prosthetic joint infections. These definitions have been divided into 3 sections: VAD-specific infections, VAD-related infections, and non-VAD infections. Owing to the constant shortage of donor organs, new allocation systems, and improved medical therapies for congestive cardiac failure, the overwhelming trend in cardiac transplantation has been toward listing principally the most critically ill patients, that is, those requiring inpatient inotropic therapy for mechanical circulatory support (MCS). The ventricular assist device (VAD) has an expanding role in the management of these patients, both as a bridge to transplantation and as a destination therapy (ie, alternative to transplantation). According to United Network of Organ Sharing (UNOS) registry data, 9,000 transplant candidates have undergone MCS since 1999, comprising 33% of all listed patients and 75% of all listed inpatients. 1

Mechanical circulatory supportPredictors of Death and Transplant in Patients With a Mechanical Circulatory Support Device: A Multi-institutional Study

BACKGROUND INTERMACS is a registry of FDA-approved durable mechanical circulatory support (MCS) devices used for the strategies of destination therapy (DT) and bridge to transplantation (BTT) or recovery. This study identifies predictors for death and transplantation based on initial results from INTERMACS. METHODS From June 23, 2006 to December 31, 2007, 420 patients from 75 institutions were prospectively entered into the INTERMACS database in which pre-implant data, indication for MCS device use, adverse events, demographics, hemodynamics, laboratory values and outcomes were recorded. Using competing outcomes methodology, risk factors were identified for the events of death and transplantation. RESULTS The devices included 314 left ventricular assist devices (LVADs), 5 right VADs (RVADs), 77 biventricular VADs (biVADs) and 24 total artificial hearts (TAHs) for a total of 497 pumps in 420 patients. Among the BTT patients at 6 months, 33% were alive with a device in place, 42% were transplanted, 22% had died, and 3% were explanted for recovery. Among the DT patients at 6 months, 68% were alive with a device in place, 5% were transplanted, 25% had died, and 2% were explanted for recovery. The risk factors identified for death across all patient groups include older age (relative risk [RR] = 1.41, p < 0.001), ascites (RR = 2.04, p = 0.003), increased bilirubin (RR = 1.49, p < 0.05) and INTERMACS Level 1 (cardiogenic shock) (RR = 1.59, p = 0.02). The most common causes of death were central nervous system (CNS) event (18.3% of deaths), multiple-organ failure (16.4%) and cardiac cause (right ventricular failure and arrhythmias, 15.4%). CONCLUSIONS Cardiogenic shock, advanced age and severe right heart failure manifested as ascites or increased bilirubin are risk factors for death after MCS therapy. BTT patients who require biVAD support have a transplant rate similar to that of LVAD-only patients, but their mortality at 6 and 12 months exceeds that of LVAD-only patients. Consideration should be given to MCS referral before the sequelae of right ventricular failure dominate the advanced heart failure syndrome.

Infection in ventricular assist devices: prevention and treatment

Infection is one of the most important challenges to the use of implanted mechanical circulatory support systems (MCSS), particularly as we enter the era of permanent device use in patients who are not candidates for cardiac transplantation. This paper describes the pathogenesis of MCSS infection, with particular attention to the role of biofilm-forming bacteria. Suggestions are presented for the prevention and treatment of infections in implanted MCSS.

Continuous-flow devices and percutaneous site infections: Clinical outcomes

BACKGROUND Although continuous-flow left ventricular assist device (LVAD) support has become standard therapy, the complexities of device and patient management remain a challenge. In particular, percutaneous site infections (PSI) are a serious complication during the post-implant course. We sought to study the incidence, risk factors, and clinical effect of PSI. METHODS Data were obtained from the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) Registry. All adult patients who received a primary intracorporeal continuous flow LVAD between June 2006 and September 2010 were included. Descriptive statistics, Kaplan-Meier depictions, and multivariable analysis in the parametric hazard domain were used for statistical analysis. RESULTS A total of 239 PSIs were documented in 197 of 2,006 recipients (9.8%) of a continuous-flow LVAD. Mean follow-up was 8.1 months. Mean time to development of a PSI was 6.6 months. At 1 year after implant, nearly 19% of continuous-flow LVAD recipients developed a PSI. Multivariate analysis showed younger age (hazard ratio, 1.20; p < 0.0001) was the only factor predicting a PSI. Continuous-flow LVAD recipients who did not develop a PSI had improved survival (p = 0.004). Twenty-three patients died after development of a PSI. Sepsis was the most common cause of death (26.1%). CONCLUSIONS PSIs occur in approximately 19% of continuous-flow LVAD recipients by 12 months after implant. Young age is the only predictor of PSI. Importantly, development of a PSI adversely affects survival. Efforts to enhance driveline integration and to develop future totally implantable systems are warranted.

Benefits of a novel percutaneous ventricular assist device for right heart failure: The prospective RECOVER RIGHT study of the Impella RP device

BACKGROUND Right ventricular failure (RVF) increases morbidity and mortality. The RECOVER RIGHT study evaluated the safety and efficacy of a novel percutaneous right ventricular assist device, the Impella RP (Abiomed, Danvers, MA), in a prospective, multicenter trial. METHODS Thirty patients with RVF refractory to medical treatment received the Impella RP device at 15 United States institutions. The study population included 2 cohorts: 18 patients with RVF after left ventricular assist device (LVAD) implantation (Cohort A) and 12 patients with RVF after cardiotomy or myocardial infarction (Cohort B). The primary end point was survival to 30 days or hospital discharge (whichever was longer). Major secondary end points included indices of safety and efficacy. RESULTS The patients (77% male) were a mean age of 59 ± 15 years, 53% had diabetes, 88.5% had a history of congestive heart failure, and 37.5% had renal dysfunction. Patients were on an average of 3.2 inotropes/pressors. Device delivery was achieved in all but 1 patient. Hemodynamics improved immediately after initiation of Impella RP support, with an increase in cardiac index from 1.8 ± 0.2 to 3.3 ± 0.23 liters/min/m(2) (p < 0.001) and a decrease in central venous pressure from 19.2 ± 4 to 12.6 ± 1 mm Hg (p < 0.001). Patients were supported for an average of 3.0 ± 1.5 days (range, 0.5-7.8 days). The overall survival at 30 days was 73.3%. All patients discharged were alive at 180 days. CONCLUSIONS In patients with life-threatening RVF, the novel percutaneous Impella RP device was safe, easy to deploy, and reliably resulted in immediate hemodynamic benefit. These data support its probable benefit in this gravely ill patient population.