Prognostic Role Of Cardiopulmonary Exercise Testing In Wild Type Transthyretin Amyloid Cardiomyopathy Patients Treated With Tafamidis

Abstract

<h3>Background</h3> Prognostic value of cardiopulmonary exercise test (CPET) in heart failure with reduced ejection fraction is well established, but it's utility in wild type transthyretin cardiac amyloidosis (wtATTR) patients treated with Tafamidis is unknown. <h3>Objective</h3> To determine the role of baseline CPET in Tafamidis treated wtATTR amyloid patients. <h3>Methods</h3> A retrospective study was conducted to identify wtATTR patients who were treated with Tafamidis and underwent baseline CPET at The University of Kansas Amyloid Clinic from 8/31/2018 until 3/31/2020. Univariate and multivariate logistic regression models were used to predict the occurrence of the primary outcome (composite of mortality, heart transplant, and palliative inotrope initiation). <h3>Results</h3> A total of 33 patients were included with a mean age of 81 ± 5.7 years. About 84% were Caucasians and 79% were males. Mean peak oxygen consumption (VO₂) and peak circulatory power (CP) were low at 11.88 ± 3.74 ml/kg/min and 1667.8 ± 804.2 mmHg/ml/min, respectively. Mean VE/VCO₂ (Ventilatory efficiency) was 36.65 ± 8.7. After 1 year follow-up, 11 patients had reached the primary outcome. Median exercise duration was significantly lower in patients with primary outcomes compared to those without as shown in figure 1 [4.4 (IQR 3.6-4.7) vs 6.9 (IQR 5.9-8.9), p <0.001]. Upon multivariate analysis; peak VO₂ [OR 0.25, CI(0.07-0.91), p=0.03], peak CP [OR 0.99,CI(0.98-0.99), p=0.03] and peak VO₂/HR (Oxygen pulse) [OR 0.44, CI(0.22-0.87), p=0.02] were significantly associated with the primary outcome. VE/VC0₂ (Ventilatory efficiency) was not significantly associated with the primary outcome. (Table 1) <h3>Conclusion</h3> Peak V02, peak CP, and peak VO₂/HR may have a prognostic role in selecting which wtATTR patients will benefit from Tafamidis treatment.