Cardiopulmonary Exercise Testing for Cardiac Risk Assessment Prior to Kidney Transplantation
Mayo Clinic Arizona, Phoenix
Meeting: 2013 American Transplant Congress
Abstract number: 332
Background: The American Heart Association recommends achievement of 4 METS (equivalent of climbing a flight of stairs), as adequate for cardiac clearance prior to non-cardiac surgery. However, most transplant (tx) centers perform at a minimum non-invasive stress testing (NIST) to clear high risk cardiac patients for kidney tx. Cardiopulmonary exercise testing (CPX) is an effective strategy to risk stratifying patients for heart tx.
Our center has adopted CPX in the algorithm for screening before kidney tx in high cardiac risk (1 or more criteria: diabetes mellitus (DM), coronary artery disease (CAD), age >50 yrs) patients. If CPX results indicate VO2 <17 mL/kg/min (∼METS <5.5), NIST (stress MIBI) is performed and if VO2 ≥17 mL/kg/min, no further testing unless prior angioplasty or CABG wherein NIST is performed.
Aims: (1) determine the frequency of patients requiring NIST after CPX (2) compare characteristics & early post-tx outcomes among those with VO2 <17 to ≥17 mL/kg/min
Results: N= 29 patients with 2-6 month post-tx follow-up. Mean age: 57±11 yrs, 52% DM, 14% CAD, 86% HTN, 40% smokers, mean pre-tx BMI 30 ±5 kg/m2, 34% pre-tx troponin >0.03 ng/mL.
| VO2 <17 mL/kg/min (n=20) | VO2 ≥17 mL/kg/min (n=9) | p value | |
| DM (%) | 70 | 11 | 0.003 |
| Living donor (%) | 15 | 78 | 0.001 |
| Preemptive tx (%) | 15 | 56 | 0.02 |
| CAD (%) | 20 | 0 | 0.14 |
| Pre-tx ejection fraction* | 58±16 | 65±4 | 0.05 |
| Troponin >0.03 ng/mL (%) | 45 | 11 | 0.07 |
| Delayed graft function (%) | 5 | 0 | 0.09 |
| Days post-tx hospital stay* | 4.4±1.5 | 3.1±0.6 | 0.03 |
No significant differences in age, sex, BMI, % CAD, HTN and smokers between the 2 groups. 4 of 9 with VO2 ≥ 17 inadvertently received MIBI (was normal). Only 2 patiens had abnormal MIBI (with ischemia) both with VO2 of <17.
No cardiac event, graft loss or mortality post-tx was noted in this albeit short follow-up period.
Conclusions:
(1) Incorporation of CPX is potentially a safe and cost-saving risk stratification strategy for pre-kidney tx cardiac screening. In our center, MIBI costs ∼$2000 and CPX ∼$200. Elimination of MIBI in patients with good VO2 (>17ml/kg/min) in this small but representative cardiac high risk cohort represents:(i) potential cost savings of ∼ $1800 per patient (ii) avoidance of radiation exposure from the MIBI.
(2) Lower VO2 correlated to longer hospital stay post-tx; however, our sample size was not robust to perform multivariate analyses adjusting for cofounders.
To cite this abstract in AMA style:
Chakkera H, Roy S, Steidley E, Kalya A, Reddy K, Mulligan D, Heilman R, Hewitt W, Khamash H, Huskey J, Moss A, Katariya N, Scott R. Cardiopulmonary Exercise Testing for Cardiac Risk Assessment Prior to Kidney Transplantation [abstract]. Am J Transplant. 2013; 13 (suppl 5). https://atcmeetingabstracts.com/abstract/cardiopulmonary-exercise-testing-for-cardiac-risk-assessment-prior-to-kidney-transplantation/. Accessed May 17, 2025.« Back to 2013 American Transplant Congress