Author + information
- Palak Shah,
- Vivek M. Mehta,
- Jennifer A. Cowger,
- Matthew A. Romano,
- Jonathan W. Haft,
- Keith D. Aaronson and
- Francis D. Pagani
Left ventricular assist device (LVAD) therapy is associated with a chronic low-grade hemolysis. More clinically significant hemolysis can occur in the setting of pump thrombus. Serum free hemoglobin (SFH) has been used to detect hemolysis within clinical trials. Lactate dehydrogenase (LDH) is also a recommended measure of hemolysis, but to date no threshold value for abnormal has been defined in LVAD recipients.
From 2003 to 2012 we implanted 254 continuous-flow LVADs. From this cohort we identified 188 patients who had no laboratory or clinical evidence of hemolysis (ie, heart failure, bilirubinuria) or suspected pump thrombosis (including sustained power elevations) to serve as our control group. Our control group was then further divided into those who had an axial-flow (AF, n = 147) v. centrifugal-flow (CF, n = 41) LVAD implanted. The mean LDH ± two standard deviations, was defined as the threshold for clinically significant hemolysis. To calculate the sensitivity and specificity of this newly defined LDH threshold, we identified an additional 23 AF LVAD patients with confirmed pump thrombosis and analyzed them with the 147 AF control patients.
The mean LDH in patients supported with an AF LVAD was higher than a CF LVAD (367 ± 103 v. 266 ± 76, P < 0.0001), but there was no difference in mean SFH (10.9 ± 13.3 v. 11.5 ± 18.9, P = 0.412). The mean LDH in AF LVAD patients who had confirmed pump thrombosis was higher than controls (1277 ± 849 v. 367 ± 103, P < 0.0001) as was the SFH (38.6 ± 43.6 v. 10.9 ± 13.3, P < 0.0001). The area under the receiver operating characteristic curve (AUC) for LDH as a marker of pump thrombosis was significantly higher (AUC = 0.94 ± 0.01) than SFH (AUC = 0.82 ± 0.01, p < 0.05). Using the mean LDH ± two standard deviations resulted in a threshold of 573 for AF LVADs and 418 for CF LVADs. In AF LVADs, a threshold for LDH of 573 resulted in a sensitivity of 85% and specificity of 95% for pump thrombosis. The modified Interagency Registry for Mechanically Assisted Circulatory Support threshold of SFH = 40 had a sensitivity of only 28% with a specificity of 97%.
Baseline LDH values differ between AF and CF LVADs. LDH was a superior predictor of clinically significant hemolysis than SFH.
Oral Contributions South, Room 102
Sunday, March 10, 2013, 8:45 a.m.-9:00 a.m.
Session Title: Cardiac Transplantation and Mechanical Support
Abstract Category: 15. Heart Failure: Clinical
Presentation Number: 915-6
- 2013 American College of Cardiology Foundation