60 M. Raguindin et al.: J Extra Corpor Technol 2026, 58, 57--64
Table 3. Institutional protocol nomogram for high-dose bivalirudin protocol.
|
MCS High Intensity Dosing Nomogram |
|
aPTT( seconds) |
Dosage Adjustments |
Repeat aPTT |
|
Hold infusion |
Drip change |
CrCl > 30 mL / min |
CrCl < 30 mL / min or CRRT / iHD |
aPTT < 45 |
n / a |
Increase infusion rate by 40 % |
aPTT in 2 h |
aPTT in 4 h |
aPTT 45--59.9 |
n / a |
Increase infusion rate by 20 % |
aPTT in 2 h |
aPTT in 4 h |
aPTT 60--80 |
n / a |
No Change( therapeutic) |
aPTT in 2 h |
aPTT in 4 h |
aPTT 80.1--100 |
Hold infusion |
Decrease infusion rate by 30 % |
aPTT in 2 h after resuming |
aPTT in 4 h after resuming |
|
for 30 mins |
|
|
|
aPTT 100.1--179.9 |
Hold infusion for 60 mins |
Decrease infusion rate by 40 % |
STAT aPTT every hour until aPTT < 100, then aPTT in 2 h after resuming |
STAT aPTT every hour until aPTT < 100, then aPTT in 4 h after resuming |
aPTT > 180 |
Recheck STAT aPTT as soon as infusion held to make sure the value is not an artifact due to bivalirudin contamination |
of specimen. After obtaining follow-up aPTT, adjust via nomogram if applicable. If aPTT remains > 180, contact CT |
Surgery provider to discuss recommendations |
Table 4. Baseline characteristics.
|
Pre-Group( N = 38) |
Post-Group( N = 35) |
P-Value |
Age, years, median( IQR) |
63.5( 57--70) |
55( 44.5--65.6) |
0.181 |
Sex, female, n(%) |
10( 26.3 %) |
9( 25.7 %) |
0.953 |
Weight, kg, median( IQR) |
97.1( 84.9--109.3) |
96.2( 85.3--107.1) |
0.395 |
BMI, kg / m 2, median( IQR) |
30( 26--34) |
33.1( 28.8--37.5) |
0.277 |
Baseline coagulopathy, n(%) |
16( 42.1 %) |
16( 45.7 %) |
0.756 |
Therapeutic anticoagulation prior to ECMO, n(%) |
N / A |
14( 40 %) |
N / A |
VTE |
|
7 |
|
ACS |
|
5 |
|
AFib |
|
1 |
|
HIT |
|
1 |
|
BMI: Body mass index; VTE: Venous thromboembolism; ACS: Acute coronary syndrome; AFib: Atrial fibrillation; HIT: Heparin-induced thrombocytopenia.
of patients in the post-group were receiving therapeutic anticoagulation prior to ECMO initiation.
While the pre-group was predominantly cannulated for veno-arterial( VA) ECMO, the post-group was treated equally with both VA and veno-venous( VV) ECMO, with the postgroup also having predominantly peripheral cannulation. The median duration of ECMO for both groups was about one week. Respiratory illness was a more common indication for ECMO in the post-group, with 25.7 % of all patients having COVID-19. Incidence of renal failure during ECMO was significantly lower in the pre-group( 54.3 % vs. 74.3 %, p = 0.033; Table 5).
Primary outcome
The median time to two consecutive aPTTs within therapeutic range for the initial goal range was 8.9 h in the pre-group and 14.2 h in the post-group( p = 0.517; Table 6). Excluding the nine COVID-19 patients from the post-group analysis, the mediantimewas8.6h( p = 0.615). Four patients in the pre-group and six patients in the post-group were not included in the analysis of the primary outcome due to only having a single aPTT drawn in the initial goal range, discontinuation of bivalirudin, or a change in the aPTT goal prior to two consecutive therapeutic aPTTs.
Secondary outcomes( post-group)
The post-group had further aPTT characterization( Table 6). The median percentage of aPTTs out of range after achieving two consecutive therapeutic aPTTs was 14.3 % including all patients and 9.1 % excluding COVID-19 patients. The median percentage of subtherapeutic aPTT values was higher at 8.3 % compared to 4.7 % supratherapeutic values. There was a median of one aPTT goal range adjustment while patients were on bivalirudin.
Twelve patients died while on ECMO in the post-group, three of whom were COVID-19 patients. Seventeen patients, including two COVID-19 patients, survived to hospital discharge.
Safety outcomes
Safety outcomes of bleeding and VTE are shown in Table 7. Bleeding occurred in 23.7 % of the pre-group compared to 11.4 % in the post-group( p = 0.172). Additional endpoints related to bleeding were collected for the post-group only. A major bleed occurred in 31.4 % of patients in the post-group. The most common type of major bleed was retroperitoneal.
Systemic VTE occurred in 7.9 % of the pre-group and 5.7 % of the post-group( p = 0.763). There was significantly more