Protamine for Heparin Reversal After Carotid Endarterectomy is Significantly Underutilised: Results from a UK National Survey

Cumulative Risks for Reoperation Due to Bleeding After Carotid Endarterectomy and The Associated Clinical Impact of Bleeding Events

OBJECTIVE

The purpose of this study was to identify all preoperative and intraoperative variables in the Vascular Quality Initiative (VQI) carotid endarterectomy (CEA) module that have a statistically significant association with reoperation for bleeding. A weighted risk score was developed and validated to predict this event, with assessment of its impact on 30-day mortality and other adverse perioperative events.

METHODS

The VQI CEA module was queried between January 2003 and October 2023. Overall, 192,547 CEA procedures met study inclusion. An internal VQI validation cohort was created with the same exclusion criteria utilizing CEA performed between November 2023 and October 2024 over which time period 17,449 procedures met inclusion criteria.

RESULTS

The following variables had a statistically significant multivariable association (P<.05) with reoperation for bleeding after CEA : Black race (adjusted odds ratio (aOR) 1.53); BMI <20 kg/m2 (aOR 1.40); hypertension (aOR 1.19); history of CAD revascularization (aOR 1.16); CHF (aOR 1.37); COPD (aOR 1.19); dual antiplatelet at time of surgery (aOR 1.51); on anticoagulation baseline (aOR 1.23); preoperative Rankin score 2 or higher (aOR 1.41); urgent/emergent CEA (aOR 1.36); eversion CEA technique (aOR 1.33); surgeon selection for drain placement (aOR 1.17); and, lack of protamine utilization intraoperatively (aOR 2.08). The following variables had a significant (P<.05) protective effect versus reoperation for bleeding after CEA : female sex (aOR .84); BMI>35 kg/m2; and active smoking status (aOR 0.85). Patients with risk scores of zero or less had an only .006% risk of return to the operating room for bleeding. There was significant elevation in risk for return to the operating room for bleeding with escalating risk sores. Patients with risk scores 11 and higher had an absolute reoperation for bleeding event rate of 3.6% which was a total event rate 600 times higher than individuals with scores of 0 or less and 3.6 times as high as individuals with scores as high as 5. The internal VQI validation cohort experienced the event of return to the operating room for bleeding at very similar rates to the primary study source cohort with no statistically significant difference at any of the risk score points indicating consistency for the risk score. Patients who experienced return to the operating room for bleeding after CEA experienced a statistically significant increased rate of : 30 day mortality (OR 1.59); cranial nerve injury (OR 2.03); perioperative neurological event (OR 5.80); myocardial infarction (MI) (OR 6.56); cardiac dysrhythmia (OR 4.20); perioperative congestive heart failure (CHF) (OR 5.26); and skin-soft tissue infection (SSI) postoperatively (OR 12.61) with P<.001 for all.

CONCLUSIONS

A validated quantitative risk score has been developed to predict reoperation for bleeding after carotid endarterectomy (CEA). The most impactful variables, which are also largely modifiable, include intraoperative protamine utilization and avoidance of dual antiplatelet therapy. Patients who experience reoperation for bleeding after CEA experience significantly higher rates of 30-day mortality, MI, CHF, cranial nerve injury, SSI, and adverse perioperative neurological events.

Perprocedural Heparinization in Non-cardiac Arterial Procedures: The Current Practice in the Netherlands

PURPOSE

Heparin is the most widely-used anticoagulant to prevent thrombo-embolic complications during non-cardiac arterial procedures (NCAP). Unfortunately, there is a lack of evidence and consequently non-uniformity in guidelines on perprocedural heparin management. Detailed insight into the current practice of antithrombotic strategies during NCAP in the Netherlands is important, aiming to identify potential optimal protocols and local differences concerning perprocedural heparinization.

MATERIALS AND METHODS

A comprehensive online survey was distributed electronically to vascular surgeons of every hospital in the Netherlands in which NCAP were performed. Data were collected from September 2020 to October 2021.

RESULTS

The response rate was 90% (53/59 hospitals). During NCAP, all surgeons generally administered heparin before arterial clamping. In 74% (39/54) of hospitals, a single heparin dosing protocol was used for all types of patients and vascular procedures. In 40%, there was no uniformity in heparin dosing between vascular surgeons. Depending on the procedure, a fixed bolus heparin, predominantly 5000 IU, was administered in 73% to 93%. In the remaining hospitals (7%-27%), a bodyweight-based heparin protocol was used, with an initial dose of 70 or 100 IU/kg. A minority (28%) monitored the effect of heparin in patients using the activated clotting time add (ACT) after activated clotting time. Target values varied between 180 and 250 seconds or 2 times the baseline ACT.

CONCLUSION

This survey demonstrates considerable variability in perprocedural heparinization during NCAP in the Netherlands. Future research on heparin dosing is needed to harmonize and optimize heparin dosage protocols and contemporary guidelines during NCAP, and thereby improve vascular surgical care and patient safety.

CLINICAL IMPACT

This survey demonstrated persisting intra- and inter-hospital variability in perprocedural heparinization during non-cardiac arterial procedures (NCAP) in the Netherlands. The observed variability in heparinization strategies highlights the need for high quality evidence on perprocedural anticoagulation strategies. This is needed in order to harmonize and optimize heparin dosage protocols and contemporary guidelines and thereby improve vascular surgical patient care. Based on the current results, an international survey will be conducted by the authors to gain additional insight into the antithrombotic strategies used during NCAP, aiming to harmonize anticoagulation protocols worldwide.