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

95th Annual AATS Meeting, Seattle, WAApril 28th, 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%.

Kormos et al. JTCVS 2010;139:1316-24

The causes are multi-factorial.

RV failure & RVAD after LVAD are well described as significant, independent risk factors for morbidity & mortality.

BackgroundIdentifying 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 (106/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/m2) 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 Probability of RVAD  

Low risk (0-5)

Intermediate risk (6-16)

High risk (17-27)

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. TR (any)

Renal replacement therapyAlbumin (<normal)

Previous sternotomyPressor requirementSmall LV cavity (<6cm)

The TRAPPS risk score, is a simple, portable, accurate & validated, pre-operative score to identify patients at risk for RVAD after CF LVAD.

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

95th Annual AATS Meeting, Seattle, WAApril 28th, 2015