A Validated Practical Risk Score to Predict the Need for RVAD after Continuous-flow LVAD SK Singh MD MSc, DK Pujara MBBS, J Anand MD, WE Cohn MD, OH Frazier MD, HR Mallidi MD Division of Transplant & Assist Devices, Baylor College of Medicine Houston, Texas, USA 95 th Annual AATS Meeting, Seattle, WA April 28 th, 2015
Disclosures The authors have NO disclosures relevant to this research project.
Background RV failure after LVAD implant occurs in 20-50% of patients. Severe RV failure post-lvad, requiring RVAD support has an incidence of 10-25%. The causes are multifactorial. RV failure & RVAD after LVAD are well described as significant, independent risk factors for morbidity & mortality. Kormos et al. JTCVS 2010;139:1316-24
Background Identifying patients high risk for RVAD after LVAD, may improve outcomes via: Peri-operative RV optimization Lower threshold for RVAD support Alternate strategies (Transplant, TAH, planned BiVAD) Existing risk scores are limited: RV failure outcome, vs RVAD Inconsistent variables Few reproduced Small sample sizes Based on univariate analyses Include obsolete pulsatile LVADs None have been robustly validated
Objective To review the largest single-center experience with CF LVADS to create a simple, portable & robustly validated risk score, that accurately predicts patients at risk for a RVAD after CF LVAD.
Methods A retrospective review of consecutive patients implanted with a CF LVAD at our single institution (1999 2013) N = 469 patients. Stratified by RVAD required during admission for CF LVAD. n = 42 RVADs (9.0%) Univariate summary statistics & Kaplan-Meier survival. Multivariable logistic regression identified predictors of requiring RVAD.
Methods Risk Score: Predictors dichotomized at clinically relevant thresholds; weighted odds ratios Created simple acronym & simple to remember risk coefficients ROC AUC c-statistics were calculated for accuracy Validated internally Bootstrapping (case resampling) Validated prospectively - 2014 patient cohort (N=78)
Results
RVAD Incidence Era
RVAD Survival
Baseline Characteristics CF LVAD (n=427) +RVAD (n=42) Age (years) 54 + 14 54 + 15 Ischemic Etiology 175 (41%) 20 (48%) Bridge-to-transplant 254 (59%) 26 (62%) INTERMACS 1 or 2 219 (53%)* 31 (77%)* Inotropic Support 361 (84%)* 41 (98%)* Vasopressor Support 59 (14%)* 12 (29%)* Pre-operative temporary circulatory support Extra-corporal membrane oxygenation (ECMO)** Abiomed Impella or TandemHeart** Intra-aortic balloon pump (IABP)** 214 (50%)* 1 (0.2%) 63 (14.8%)* 184 (43.1%)* 30 (71%)* 2 (4.8%) 12 (28.6%)* 24 (57.1%)*
Baseline Characteristics CF LVAD (n=427) +RVAD (n=42) Diabetes 178 (42%) 15 (36%) Chronic Obstructive Pulmonary Disease 55 (13%) 3 (7%) Renal Replacement Therapy 20 (5%)* 9 (21%)* Hemoglobin (g/dl) 11.7+2.1 11.1+1.9 White blood count (10 6 /ml) 9.0+4.1* 11.6+5.4* Sodium (meq/l) 135+4.5 136+6.2 Creatinine (mg/dl) 1.4+0.7 1.6+0.8 Albumin (g/dl) 3.7 + 1.4* 3.2 + 0.5*
Hemodynamics CF LVAD (n=427) +RVAD (n=42) CI (L/min/m 2 ) 1.9 + 0.6 1.9 + 0.6 PCWP (mmhg) 25 + 10 23 + 9 CVP (mmhg) 12 + 7 14 + 9 PVR (Wood s Units) 3.5 + 2.7 4.4 + 2.7 LVEDD (cm) 6.7 + 1.1* 6.1 + 1.3* TR (mod sev) 170 (43%)* 24 (60%)* MR (mod sev) 230 (57%) 25 (63%) RV depression (mod-sev) 287 (73%) 32 (86%)
Operative CF LVAD (n=427) +RVAD (n=42) Previous Sternotomy 144 (34%)* 21 (50%)* Operative Approach Sternotomy Thoracotomy Subcostal/Other 366 (86%) 37 (9%) 19 (5%) 35 (83%) 6 (14%) 1 (2%) CPB (minutes) 84 + 48* 128 + 66* Concomitant Procedure Atrial septal defect repair** Tricuspid valve repair/replacement** Mitral valve repair/replacement** Aortic valve repair/replacement** Left ventricle geometry restoration** Coronary artery bypass grafting** 159 (37%) 45 (10.5%) 7 (1.6%)* 49 (11.5%) 16 (3.7%) 29 (6.8%) 14 (3.3%) 22 (52%) 7 (16.7%) 3 (7.1%)* 4 (9.5%) 2 (4.8%) 4 (9.5%) 3 (7.1%)
Predictors of RVAD OR (95% CI) P-value Tricuspid regurgitation (1-4) 1.6 (1.1-2.5) 0.03 Renal Replacement Therapy (yes/no) 2.9 (1.1-8.2) 0.04 Albumin (g/dl) 0.3 (0.1-0.6) <0.001 LVEDD (cm) 0.6 (0.4-0.8) 0.01 Previous sternotomy 1.7 (0.8-3.5) 0.2 Vasopressor use preoperatively 1.4 (0.6-3.6) 0.5
TRAPPS Predictor Odds Ratio TRAPPS Score (Total = 27) Tricuspid regurgitation (any) 2.5 5 Renal Replacement Therapy (yes/no) 3.5 7 Albumin (low; <3.5 g/dl) 2.6 5 Previous sternotomy (yes/no) 1.7 3 VasoPressor required (yes/no) 1.8 4 Small LV cavity size (LVEDD <6 cm) 1.5 3 TRAPPS SCORE Low risk (0-5) Intermediate risk (6-16) High risk (17-27) Probability of RVAD 2.5% 10% 25%
Accuracy (N=469) TRAPPS (continuous) TRAPPS (risk groups)
Validation - Bootstrapping
Validation Prospective (n=78) TRAPPS (continuous) TRAPPS (risk groups)
Conclusions Severe RV failure requiring RVAD after CF LVAD is a significant risk factor for considerable early mortality. This review of the largest, single-center CF LVAD experience found a 9% incidence of RVAD after CF LVAD. The TRAPPS risk score, is a simple, portable, accurate & validated, pre-operative score to identify patients at risk for RVAD after CF LVAD. TR (any) Renal replacement therapy Albumin (<normal) Previous sternotomy Pressor requirement Small LV cavity (<6cm)
Conclusions The TRAPPS variables are intuitive & reproduced in literature. The score is novel in its robust validation retrospectively, prospectively & derived from a large cohort of solely CF LVADs. Limitations include external validation (pending), and exclusion of important intra-operative variables (i.e. transfusions). While TRAPPS accurately identifies those at risk for RVAD, there remains a large margin where further aspects of a heart failure program s practice may impact RVAD incidence.
A Validated Practical Risk Score to Predict the Need for RVAD after Continuous-flow LVAD SK Singh MD MSc, DK Pujara MBBS, J Anand MD, WE Cohn MD, OH Frazier MD, HR Mallidi MD Division of Transplant & Assist Devices, Baylor College of Medicine Houston, Texas, USA 95 th Annual AATS Meeting, Seattle, WA April 28 th, 2015