Cangrelor and Heparin for Pulmonary Thromboendarterectomy in Heparin-Induced Thrombocytopenia

Efficacy of Therapeutic Plasma Exchange or Cangrelor as an Adjunctive Strategy to Facilitate Cardiopulmonary Bypass in Patients with Heparin-Induced Thrombocytopenia: A Systematic Review and Meta-Analysis

OBJECTIVE

Conduct a systematic review and meta-analysis of the efficacy of therapeutic plasma exchange (TPE) or intravenous cangrelor to prevent thromboembolism in patients with heparin-induced thrombocytopenia (HIT) who undergo cardiopulmonary bypass (CPB) with heparin.

DESIGN

Systematic review and meta-analysis.

SETTING

N/A.

PARTICIPANTS

Adults having cardiac surgery with a history of HIT who received preoperative or intraoperative TPE or intravenous cangrelor as an adjunct to CPB with heparin.

INTERVENTIONS

None MEASUREMENTS AND MAIN RESULTS: A systematic review was performed using MEDLINE, PubMed, and Google Scholar. The primary outcome was avoidance of thromboembolism (venous or arterial) during or after CPB. Proportional meta-analysis with a random effects model was used to calculate a weighted-pooled proportion/efficacy for the study's primary outcome. Fifty-seven patients in 17 reports received TPE as an adjunctive treatment to prevent HIT-related thrombosis related to heparinization during CPB and 3 (5.3%) experienced thrombosis. Proportional meta-analysis suggested a weighted-pooled freedom from perioperative thromboembolism rate of 91.0% (95% CI 82.6%-96.9%). Fifteen patients in 6 reports received intravenous cangrelor as an adjunctive treatment to prevent HIT-related thrombosis related to heparinization during CPB and 2 (13.3%) experienced thrombosis. Proportional meta-analysis suggested a weighted-pooled freedom from perioperative thromboembolism rate of 83.0% (95% CI 61.2%- 97.6%).

CONCLUSIONS

TPE and cangrelor are feasible strategies to prevent thromboembolism in adults with HIT who require CPB with heparin. Given the relatively small number of cases in the published literature and a high likelihood for publication and detection biases, prudence remains warranted when using these strategies.

Cangrelor for cardiopulmonary bypass in patients with heparin-induced thrombocytopenia: it is not so easy

Anticoagulation management for cardiopulmonary bypass (CPB) is challenging in patients with acute heparin-induced thrombocytopenia (HIT). The strategy of combining cangrelor intraoperatively with heparin for CPB anticoagulation is of increasing interest but exposes to specific unresolved problems. We report the case of a patient requiring surgical pulmonary embolectomy for pulmonary embolism at the very acute phase of HIT, with a high titre of anti-PF4/heparin antibodies and severe thrombocytopenia. For CPB management, cangrelor was administered in combination with heparin prescribed and monitored as usual. Surgery was successfully performed, but postoperatively, the patient developed a new thrombotic event. We discussed the specific problems associated with such strategy, including the dose of cangrelor and its monitoring, the management of the cell-saver, the risk of heparin rebound and the risk of platelet transfusion. These issues must be addressed before considering the combination of cangrelor and unfractionated heparin as a standard of care for CBP.

Thrombocytopenia: Perioperative Considerations for Patients Undergoing Cardiac Surgery

The etiologies of thrombocytopenia in patients presenting for cardiac surgery are extensive, but clinically relevant conditions generally can be categorized by those related to decreased platelet production or increased platelet destruction. Many causes require mere acknowledgment and availability of allogeneic platelet transfusion; others have unique considerations for which providers should be familiar. The purpose of this review is to provide an overview of the common causes of thrombocytopenia, summarize the literature, and discuss perioperative considerations for patients undergoing cardiac surgery.