J.C. Matthews

The Right Ventricular Failure Risk Score: A Pre-Operative Tool for Assessing the Risk of Right Ventricular Failure in Left Ventricular Assist Device Candidates

OBJECTIVESnThis study sought to develop a model that estimates the post-operative risk of right ventricular (RV) failure in left ventricular assist device (LVAD) candidates.nnnBACKGROUNDnRight ventricular failure after LVAD surgery is associated with increased morbidity and mortality, but identifying LVAD candidates at risk for RV failure remains difficult.nnnMETHODSnA prospectively collected LVAD database was evaluated for pre-operative clinical, laboratory, echocardiographic, and hemodynamic predictors of RV failure. Right ventricular failure was defined as the need for post-operative intravenous inotrope support for >14 days, inhaled nitric oxide for > or =48 h, right-sided circulatory support, or hospital discharge on an inotrope. An RV failure risk score (RVFRS) was created from multivariable logistic regression model coefficients, and a receiver-operating characteristic curve of the score was generated.nnnRESULTSnOf 197 LVADs implanted, 68 (35%) were complicated by post-operative RV failure. A vasopressor requirement (4 points), aspartate aminotransferase > or =80 IU/l (2 points), bilirubin > or =2.0 mg/dl (2.5 points), and creatinine > or =2.3 mg/dl (3 points) were independent predictors of RV failure. The odds ratio for RV failure for patients with an RVFRS < or =3.0, 4.0 to 5.0, and > or =5.5 were 0.49 (95% confidence interval [CI] 0.37 to 0.64), 2.8 (95% CI 1.4 to 5.9), and 7.6 (95% CI 3.4 to 17.1), respectively, and 180-day survivals were 90 +/- 3%, 80 +/- 8%, and 66 +/- 9%, respectively (log rank for linear trend p = 0.0045). The area under the receiver-operating characteristic curve for the RVFRS (0.73 +/- 0.04) was superior to that of other commonly used predictors of RV failure (all p < 0.05).nnnCONCLUSIONSnThe RVFRS, composed of routinely collected, noninvasive pre-operative clinical data, effectively stratifies the risk of RV failure and death after LVAD implantation.

Patient selection for left ventricular assist devices

Heart transplantation (HTx) improves symptoms and prolongs life in advanced heart failure (HF), but organ supply is limited. In recent years, mechanical circulatory support and specifically implantable left ventricular assist devices (LVADs) have undergone technical improvements, and outcomes have improved dramatically. Left ventricular assist devices are now viable options for patients with severe HF as bridge to transplantation, destination therapy, or as bridge to recovery. Many believe that LVADs may soon provide outcomes similar to, or better than, HTx, launching a new era of end‐stage HF management. The key to improving outcomes is patient selection, but the field is changing rapidly and guidelines and consensus are limited. This review summarizes recent reports of predictors of poor outcomes and provides an overview of selection for LVAD therapy.

Model for End-Stage Liver Disease Score Predicts Left Ventricular Assist Device Operative Transfusion Requirements, Morbidity, and Mortality

Background— The Model for End-Stage Liver Disease (MELD) predicts events in cirrhotic subjects undergoing major surgery and may offer similar prognostication in left ventricular assist device candidates with comparable degrees of multisystem dysfunction. Methods and Results— Preoperative MELD scores were calculated for subjects enrolled in the University of Michigan Health System (UMHS) mechanical circulatory support database. Univariate and multiple regression analyses were performed to investigate the ability of patient characteristics, laboratory data (including MELD scores), and hemodynamic measurements to predict total perioperative blood product exposure and operative mortality. The ability of preoperative MELD scores to predict operative mortality was evaluated in subjects enrolled in the Interagency Registry of Mechanically Assisted Circulatory Support (INTERMACS), and results were compared with those from the UMHS cohort. The mean±SD MELD scores for the UMHS (n=211) and INTERMACS (n=324) cohorts were 13.7±6.1 and 15.2±5.8, respectively, with 29 (14%) and 19 (6%) perioperative deaths. In the UMHS cohort, median total perioperative blood product exposure was 74 units (25th and 75th percentiles, 44 and 120 units). Each 5-unit MELD score increase was associated with 15.1±3.8 units (&bgr;±SE) of total perioperative blood product exposure. Each 10-unit increase in total perioperative blood product exposure increased the odds of operative death (odds ratio, 1.05; 95% confidence interval, 1.01 to 1.10). Odds ratios, measuring the ability of MELD scores to predict perioperative mortality, were 1.5 (95% confidence interval, 1.1 to 2.0) and 1.5 (95% confidence interval, 1.1 to 2.1) per 5 MELD units for the UMHS and INTERMACS cohorts, respectively. When MELD scores were dichotomized as ≥17 and <17, risk-adjusted Cox proportional-hazard ratios for 6-month mortality were 2.5 (95% confidence interval, 1.2 to 5.3) and 2.5 (95% confidence interval, 1.1 to 5.4) for the UMHS and INTERMACS cohorts, respectively. Conclusion— The MELD score identified left ventricular assist device candidates at high risk for perioperative bleeding and mortality.

Acute Right Ventricular Failure in the Setting of Acute Pulmonary Embolism or Chronic Pulmonary Hypertension: A Detailed Review of the Pathophysiology, Diagnosis, and Management

The right ventricle (RV) is integral to normal cardiac function, but receives little attention in the medical literature. The etiologic causes of acute RV failure often differ from those encountered in left ventricular dysfunction. Thus, RV failure frequently requires diagnostic procedures and management strategies that differ from those routinely used in the management of intrinsic left ventricular dysfunction. In this summary, the structure and function of the RV will be reviewed, concentrating on the pathophysiologic mechanisms behind the development of RV dysfunction. We will then focus on two distinct populations of patients who are at risk for acute RV failure: those with chronic pulmonary arterial hypertension (PAH) and those with acute pulmonary embolism. In chronic PAH, we will examine clinical circumstances common to hospitalized patients that may provoke acute RV decompensation, as well as pharmacologic therapies that are unique to RV failure management in PAH. Individuals with acute RV failure in the setting of pulmonary embolism represent a group with particularly high mortality, and the specific diagnostic and management strategies that are important for improved survival will be discussed.

Adverse Interaction Between a Left Ventricular Assist Device and an Implantable Cardioverter Defibrillator

An increasing number of patients have a coexisting implantable cardioverter defibrillator (ICD) and left ventricular assist device (LVAD) to treat ventricular arrhythmias and refractory heart failure, respectively. To date, there have been no published reports of negative interactions between these devices that have impacted appropriate ICD or LVAD function. In this case report, we describe a patient with an LVAD‐ICD interaction that necessitated replacement of the implantable defibrillator.

Short- and Long-Term Survival of Patients Transferred to a Tertiary Care Center on Temporary Extracorporeal Circulatory Support

BACKGROUNDnMechanical circulatory support (MCS) with temporary, extracorporeal assist devices restores hemodynamics in patients with refractory cardiogenic shock. These devices are frequently used in community hospitals, with subsequent referral to tertiary care centers. We sought to determine the outcomes of such referrals and identify prognostic variables that may influence management decisions.nnnMETHODSnWe performed a single-institution retrospective review of 59 consecutive patients transferred on temporary, extracorporeal MCS from 1997 to 2008. Demographics, medical history, laboratory data, and clinical status were obtained, with survival determined from the medical record and the Social Security Death Index. Univariable and multivariable analysis were performed and survival estimates were determined using the Kaplan-Meier method.nnnRESULTSnMedian age was 49.6 years (range, 14 to 77 years). Forty-five patients (76%) were supported for postcardiotomy failure, and 34 (58%) required biventricular support. Twenty-five (42%) survived to hospital discharge, 11 after cardiac recovery (44%), 9 with long-term implantable MCS devices (39%), and 5 after heart transplantation (22%). Eight patients discharged with implantable MCS devices underwent heart transplantation and 1 remains alive on long-term implantable MCS support. Survival was 42% +/- 6% at 1 year and 38% +/- 6% at 5 years. Age and renal function were independent predictors of death.nnnCONCLUSIONSnNearly half of all patients transferred on temporary extracorporeal MCS survive to discharge. Most of the long-term survivors received a heart transplant. Age and renal function were independent predictors of death, suggesting that survival is maximized by considering eligibility for cardiac transplantation.

Sex Matters, But to What Clinical Avail?

Despite substantial advances in mechanical circulatory support, cardiac transplantation remains the “gold standard” treatment option for eligible patients with American Heart Association/American College of Cardiology class D end-stage heart failure. Transplant survival rates have progressively improved at all time points, with 55% of recipients now surviving 10 years after transplantation, despite an increase in donor and recipient age and comorbidity and greater recipient urgency. Survival has improved with every 5- to 10-year era, but most of the mortality aversion is in the first 6 to 12 months.1,2nnArticle see p 401 nnIn this issue of Circulation: Heart Failure , Weiss and colleagues3 from The Johns Hopkins University, evaluated United Network for Organ Sharing data on all first US adult heart transplantations from 1998 to 2007 (n=18,240). The authors show that female recipients had marginally ( P =0.06) worse 5-year survival than male recipients (absolute increase risk of 3.6%; 11% higher risk-adjusted mortality). However, the overall better survival in male recipients was present only in male recipients of a male donor; by using multivariable Cox modeling, they found that male recipients of a female donor (FD/MR) were 15% more likely to die than male recipients of a male donor (MD/MR). Moreover, after the addition of propensity adjustment for the likelihood of receiving a same-sex donor, the FD/MR group was 20% more likely to die than those male recipients who received a same-sex donor. The survivals of donor/recipient sex-matched female (FD/FR) and male (MD/MR) recipients were statistically indistinguishable after multivariable adjustment (with and without propensity adjustment), but when considered together, donor-recipient sex mismatches (FD/MR and MD/FR) were 14% ( P <0.001) more likely to have died at 5 years than the sex-matched group (MD/MR and FD/FR). However, among female recipients alone, the multivariable propensity-adjusted analysis revealed no increase in the risk of …