The recent success of continuous-flow circulatory support devices has led to the growing acceptance of these devices as a viable therapeutic option for end-stage heart failure patients who are not ...responsive to current pharmacologic and electrophysiologic therapies. This article defines and clarifies the major classification of these pumps as axial or centrifugal continuous-flow devices by discussing the difference in their inherent mechanics and describing how these features translate clinically to pump selection and patient management issues. Axial vs centrifugal pump and bearing design, theory of operation, hydrodynamic performance, and current vs flow relationships are discussed. A review of axial vs centrifugal physiology, pre-load and after-load sensitivity, flow pulsatility, and issues related to automatic physiologic control and suction prevention algorithms is offered. Reliability and biocompatibility of the two types of pumps are reviewed from the perspectives of mechanical wear, implant life, hemolysis, and pump deposition. Finally, a glimpse into the future of continuous-flow technologies is presented.
Heart transplant allocation in the United States is made on the basis of coarse tiers, defined by mechanical circulatory devices and therapy for advanced heart failure, updated infrequently as a ...patient’s condition deteriorates. Thus, many patients die awaiting heart transplantation. What is needed is a tool that continuously updates risk of mortality as a patient’s condition changes to inform clinical decision making.
This study sought to develop a decision aid that aggregates adverse events and measures of end-organ function into a continuously updated waitlist mortality estimate.
From 2008 to 2013, 414 patients were listed for heart transplantation at Cleveland Clinic, Cleveland, Ohio. The endpoint was waitlist death. Pre-listing patient characteristics and events and laboratory results during listing were analyzed. At each event or measurement change, mortality was recomputed from the resulting model.
There were 77 waitlist deaths, with 1- and 4-year survival of 85% and 57%, respectively. When time-varying events and measurements were incorporated into a mortality model, pre-listing patient characteristics became nonsignificant. Neurological events (hazard ratio HR: 13.5; 95% confidence interval CI: 7.63 to 23.8), new requirement for dialysis (HR: 3.67; 95% CI: 1.88 to 7.14), more respiratory complications (HR: 1.79 per episode; 95% CI: 1.23 to 2.59), and higher serum bilirubin (p < 0.0001) and creatinine (p < 0.0001) yielded continuously updated estimates of patient-specific mortality across the waitlist period.
Mortality risk for patients with advanced heart failure who are listed for transplantation is related to adverse events and end-organ dysfunction that change over time. A continuously updated mortality estimate, combined with clinical evaluation, may inform status changes that could reduce mortality on the heart transplant waiting list.
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To compare durability of tricuspid valve annuloplasty techniques, identify risk factors for repair failure, and characterize survival, reoperation, and functional class of surviving patients.
From ...1990 to 1999, 790 patients (mean age 65 ± 12 years, 51% New York Heart Association functional class III or IV, and mean right ventricular systolic pressure 56 ± 18 mm Hg) underwent tricuspid valve annuloplasty for functional regurgitation using 4 techniques: Carpentier-Edwards semi-rigid ring, Cosgrove-Edwards flexible band, De Vega procedure, and customized semicircular Peri-Guard annuloplasty. Of these patients, 89% had concomitant mitral valve surgery. A total of 2245 follow-up transthoracic echocardiograms were retrieved. Tricuspid regurgitation was analyzed, and risk factors for worsening regurgitation were identified, by multivariable ordinal longitudinal methods.
Tricuspid regurgitation 1 week after annuloplasty was 3+ or 4+ in 14% of patients. Regurgitation severity was stable across time with the Carpentier-Edwards ring (
P = .7), increased slowly with the Cosgrove-Edwards band (
P = .05), and rose more rapidly with the De Vega (
P = .002) and Peri-Guard (
P = .0009) procedures. Risk factors for worsening regurgitation included higher preoperative regurgitation grade, poor left ventricular function, permanent pacemaker, and repair type other than ring annuloplasty. Right ventricular systolic pressure, ring size, preoperative New York Heart Association functional class, and concomitant surgery were not risk factors. Tricuspid reoperation was rare (3% at 8 years), and hospital mortality after reoperation was 37%.
Tricuspid valve annuloplasty did not consistently eliminate functional regurgitation, and across time regurgitation increased importantly after Peri-Guard and De Vega annuloplasties. Therefore, these repair techniques should be abandoned, and transtricuspid pacing leads should be replaced with epicardial leads.
Insertion of an implantable left ventricular assist device (LVAD) complicated by early right ventricular (RV) failure has a poor prognosis and is largely unpredictable. Prediction of RV failure after ...LVAD placement would lead to more precise patient selection and optimal device selection.
We reviewed data from 245 patients (mean age, 54+/-11 years; 85% male) with 189 HeartMate (77%) and 56 Novacor (23%) LVADs. Ischemic cardiomyopathy predominated (65%), and 29% had dilated cardiomyopathy. Overall, RV assist device (RVAD) support was required after LVAD insertion for 23 patients (9%). We compared clinical and hemodynamic parameters before LVAD insertion between RVAD (n=23) and No-RVAD patients (n=222) to determine preoperative risk factors for severe RV failure. By univariate analysis, female gender, small body surface area, nonischemic etiology, preoperative mechanical ventilation, circulatory support before LVAD insertion, low mean and diastolic pulmonary artery pressures (PAPs), low RV stroke work (RVSW), and low RVSW index (RVSWI) were significantly associated with RVAD use. Elevated PAP and pulmonary vascular resistance were not risk factors. Risk factors by multivariable logistic regression were preoperative circulatory support (odds ratio OR, 5.3), female gender (OR, 4.5), and nonischemic etiology (OR, 3.3).
The need for circulatory support, female gender, and nonischemic etiology were the most significant predictors for RVAD use after LVAD insertion. Regarding hemodynamics, low PAP and low RVSWI, reflecting low RV contractility, were important parameters. This information may lead to better patient selection for isolated LVAD implantation.
The incidence of valvular heart disease is expected to increase over the next several decades as a large proportion of the US demographic advances into the later decades of life. At the same time, ...the next several years can be anticipated to bring a broad transition of surgical therapy to minimally invasive (minithoracotomy and small port) access and the more gradual introduction of percutaneous approaches for the correction of valvular heart disease. Broad acceptance of these technologies will require careful and sometimes perplexing comparisons of the outcomes of these new technologies with existing standards of care. The validation of percutaneous techniques, in particular, will require the collaboration of cardiologists and cardiac surgeons in centers with excellent surgical and catheter experience and a commitment to trial participation. For the near term, percutaneous techniques will likely remain investigational and will be limited in use to patients considered to be high risk or to inoperable surgical candidates. Although current-generation devices and techniques require significant modification before widespread clinical use can be adopted, it must be expected that less invasive and even percutaneous valve therapies will likely have a major impact on the management of patients with valvular heart disease over the next several years.
Optimal timing of heart transplantation in patients supported with second-generation left ventricular assist devices (LVADs) is unknown. Despite this, patients with LVADs continue to receive priority ...on the heart transplant waiting list. Our objective was to determine the optimal timing of transplantation for patients bridged with continuous-flow LVADs.
A total of 301 HeartMate II LVADs (Thoratec Corp, Pleasanton, CA) were implanted in 285 patients from October 2004 to June 2013, and 86 patients underwent transplantation through the end of follow-up. Optimal transplantation timing was the product of surviving on LVAD support and surviving transplant.
Three-year survival after both HeartMate II implantation and heart transplantation was unchanged when transplantation occurred within 9 months of implantation. Survival decreased as the duration of support exceeded this. Preoperative risk factors for death on HeartMate II support were prior valve operation, prior coronary artery bypass grafting, low albumin, low glomerular filtration rate, higher mean arterial pressure, hypertension, and earlier date of implant. Survival for patients without these risk factors was lowest when transplant was performed within 3 months but was relatively constant with increased duration of support. Longer duration of support was associated with poorer survival for patients with many of these risk factors. Device reimplantation, intracranial hemorrhage, and postimplant dialysis during HeartMate II support were associated with decreased survival.
Survival of patients supported by the HeartMate II is affected by preoperative comorbidities and postoperative complications. Transplantation before complications is imperative in optimizing survival.
The purpose of this study was to identify potential areas for quality improvement and cost containment. We investigated readmissions after HeartMate II left ventricular assist device (LVAD) ...implantation by characterizing their type, temporal frequency, causative factors, and resource use and survival after readmission.
The HeartMate II LVAD provides enhanced survival and quality of life to end-stage heart failure patients. Whether these improved outcomes are accompanied by a similar reduction in unplanned hospital readmissions is largely unknown.
From October 2004 to January 2010, 118 patients received a HeartMate II, of whom 92 were discharged on device support. Subsequent readmissions were analyzed using prospectively maintained clinical and financial databases.
Forty-eight patients (52%) had 177 unplanned hospital readmissions, 87 non-LVAD- and 90 LVAD-associated. Reasons for non-LVAD-associated readmissions included medical management of comorbidities and progression of cardiac pathology (n = 48), neuropsychiatric/psychosocial issues (n = 22), and infections (n = 17). Those for LVAD-associated readmissions included device component infection (n = 51), management of nontherapeutic anticoagulation or device malfunction (n = 22), and bleeding (n = 15). Cumulative incidence of unplanned readmissions was higher (p < 0.0001) for destination therapy than bridge-to-transplant patients (9/patient vs. 4/patient at 24 months). Cumulative hospital days overall were 25 and 42 at 12 and 18 months, respectively, and the costs were 18% and 29% of initial implantation costs. Increased number of unplanned readmissions was predictive of mortality.
Unplanned readmissions are common during HeartMate II support and negatively affect resource use and survival. Refining patient selection, especially in destination therapy patients, reducing infectious and bleeding complications, and increasing awareness about these devices might reduce unnecessary readmissions.
Bridge to transplant experience: Factors influencing survival to and after cardiac transplant Smedira, Nicholas G., MD; Hoercher, Katherine J., RN; Yoon, Dustin Y., MS ...
Journal of thoracic and cardiovascular surgery/The Journal of thoracic and cardiovascular surgery/The journal of thoracic and cardiovascular surgery,
05/2010, Letnik:
139, Številka:
5
Journal Article
Recenzirano
Odprti dostop
Objective Balancing longer duration of mechanical circulatory support while awaiting functional recovery against the increased risk of adverse events with each day on support is difficult. Therefore, ...we investigated the complex interplay of duration of mechanical circulatory support and patient and device factors affecting survival on support, as well as survival after transplantation. Methods From December 21, 1991, to July 1, 2006, mechanical circulatory support was used in 375 patients as a bridge to transplantation, with 262 surviving to transplant. Implantable pulsatile devices were used in 321 patients, continuous flow was used in 11 patients, a total artificial heart was used in 5 patients, external pulsatile devices were used in 34 patients, and extracorporeal membrane oxygenation was used in 68 patients. Two time-related models were developed: (1) a competing-risks multivariable model of death on mechanical circulatory support, with modulated renewal for each sequential support mode; and (2) a model of death after transplant in which patient factors and duration of mechanical circulatory support were investigated as risk factors. Results Survival after initiating mechanical circulatory support, irrespective of transplantation, was 86% at 30 days, 55% at 5 years, and 41% at 10 years; survival was 94%, 74%, and 58% at the same time intervals, respectively, after transplantation in those surviving the procedure. Risk factors for death included longer, but not shorter, duration of mechanical circulatory support, use of multiple devices, global sensitization, and poor renal function. Conclusion Initiating mechanical circulatory support early with a single definitive device may improve survival to and after cardiac transplantation. Early transplant, which avoids infection, sensitization, and neurologic complications, may improve bridge and transplant survival.
Improved Outcomes after Aortic Valve Surgery for Chronic Aortic Regurgitation With Severe Left Ventricular Dysfunction Sunil K. Bhudia, Patrick M. McCarthy, Ganesh S. Kumpati, Joe Helou, Katherine J. ...Hoercher, Jeevanantham Rajeswaran, Eugene H. Blackstone Patients with chronic aortic regurgitation and severe left ventricular dysfunction have been considered high risk for aortic valve surgery. We document important improvement in the safety of aortic valve surgery for these patients during the last 25 years. Eighty-eight such patients were propensity matched with an equal number having nonsevere left ventricular dysfunction undergoing aortic valve surgery. Hospital mortality decreased from 50% in 1975 to 0% in 1985, and time-related survival since then has been comparable (p = 0.96). Thus, aortic valve surgery for chronic aortic regurgitation and cardiomyopathy should no longer be considered a high-risk procedure for which transplantation is the best option.
Because duration of inotropic support after left ventricular assist device implantation has been recognized as a surrogate for right ventricular dysfunction, we sought to (1) identify its ...preimplantation risk factors, particularly its association with preimplantation right ventricular dysfunction, and (2) assess its impact on clinical outcomes.
Between 1991 and 2002, left ventricular assist devices were implanted in 207 patients, exclusive of those receiving preoperative mechanical circulatory support, which precluded measuring right ventricular stroke work. Duration of inotropic support was analyzed as a continuous variable, truncated by death or transplantation, and in turn as a risk factor for these 2 events.
Inotropic support decreased from 100% on the day of implantation to 57%, 33%, and 22% by days 7, 14, and 21. Its duration was strongly associated with lower preimplantation right ventricular stroke work index, older age, and nonischemic cardiomyopathy and was associated (
P < .04) with higher mortality before transplantation but not with transition to transplantation. We identified no preimplantation risk factors for right ventricular assist device use because of its relatively infrequent use in this population (18 patients, only 4 of whom survived to transplantation).
Duration of inotropic support after left ventricular assist device insertion is strongly correlated with low preimplantation right ventricular stroke work index. In turn, it was associated with reduced survival to transplantation. Thus, right ventricular stroke work measured before implantation might be useful in decision making for biventricular support, destination therapy, or total artificial heart.
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