Preoperative Exchange Transfusion for Sickle Cell Disease Patients Undergoing Open-Heart Surgery: An Exception to the Rule

Management of the Sickle Cell Trait: An Opinion by Expert Panel Members

The number of individuals with the sickle cell trait exceeds 300 million worldwide, making sickle cell disease one of the most common monogenetic diseases globally. Because of the high frequency of sickle cell disease, reproductive counseling is of crucial importance. In addition, unlike other carrier states, Sickle Cell Trait (SCT) seems to be a risk factor for several clinical complications, such as extreme exertional injury, chronic kidney disease, and complications during pregnancy and surgery. This expert panel believes that increasing knowledge about these clinical manifestations and their prevention and management can be a useful tool for all healthcare providers involved in this issue.

Simple open-heart surgery protocol for sickle-cell disease patients: a retrospective cohort study comparing patients undergoing mitral valve surgery

OBJECTIVES

Sickle-cell disease (SCD) patients are considered to be at high risk from open-heart surgery. This study assessed the role of a simple sickling-prevention protocol.

METHODS

Perioperative non-specific and SCD-specific morbidity and 30-day mortality are investigated in a retrospective cohort study on patients undergoing isolated mitral valve surgery. Patients with and without SCD were compared. In the SCD cohort, a bundle of interventions was applied to limit the risk of sickling: 'on-demand' transfusions to keep haemoglobin levels of around 7-8 g/dl, cardiopulmonary bypass (CPB) with higher blood flow and perfusion temperature, close monitoring of acid-base balance and oxygenation.

RESULTS

Twenty patients with and 40 patients without SCD were included. At baseline, only preoperative haemoglobin levels differed between cohorts (8.1 vs 11.8 g/dl, P < 0.001). Solely SCD patients received preoperative transfusions (45.0%). Intraoperative transfusions were significantly larger in SCD patients during CPB (priming: 300 vs 200 ml; entire length: 600 vs 300 ml and 20 vs 10 ml/kg). SCD patients had higher perfusion temperatures during CPB (34.7 vs 33.0°C, P = 0.01) with consequently higher pharyngeal temperature, both during cooling (34.1 vs 32.3°C, P = 0.02) and rewarming (36.5 vs 36.2°C, P = 0.02). No mortality occurred, and non-SCD-specific complications were comparable between groups, but one SCD patient suffered from perioperative cerebrovascular accident with seizures, and another had evident haemolysis.

CONCLUSIONS

SCD patients may undergo open-heart surgery for mitral valve procedures with an acceptable risk profile. Simple but thoughtful perioperative management, embracing 'on-demand' transfusions and less-aggressive CPB cooling is feasible and probably efficacious.

Aortic valve replacement in a patient with sickle cell disease-Are we justified to perform surgery in the TAVI era?

Not all variants of SCD need the same management and this should be decided on a case-by-case basis. Heterozygous SCD patients can undergo cardiac surgery without the need for intraoperative exchange transfusions with good clinical outcomes.

Perioperative care of children with sickle cell disease: A systematic review and clinical recommendations

Children with sickle cell disease (SCD) require specific perioperative care, and clinical practice in this area remains poorly defined. We aimed to conduct a systematic, PRISMA-based review of the literature, available clinical guidelines and practice recommendations. We also aimed to extract any valuable information for the "best of available-evidence"-based prevention of perioperative adverse events in children with SCD, and highlight the most urgent priorities in clinical research. As data sources, US National Library of Medicine, Medline, National Guideline Clearinghouse, International Guideline Network, TRIP databases were searched for any content until January 2019. We also included institutional, consortia and expert group guidelines. Included were reports/guidelines in English, French, German, and Italian. Excluded were reports on obstetrical and fetal management. We identified 202 reports/guidelines fulfilling the criteria outlined above. A majority focused on visceral, cardiovascular and orthopedic surgery procedures, and only five were multicenter randomized controlled trials and two prospective randomized studies. After grading of the quality of the evidence, the extracted data was summarized into clinical recommendations for daily practice. Additionally, we designed a risk-grading algorithm to identify contexts likely to be associated with adverse outcomes. In conclusion, we provide a systematic PRISMA-based review of the existing literature and ancillary practice and delineate a set of clinical recommendations and priorities for research.

Catastrophic sickling crisis in patient undergoing cardiac transplantation with sickle cell trait

There is debate in the literature regarding management of patients with sickle cell trait (SCT) undergoing cardiac surgery, since it is recognized that cardiopulmonary bypass presents many precipitating risk factors for a sickling crisis. Despite this, many report successful outcomes without any modification to perioperative management. A 49-year-old woman with SCT (HbS 38%) with postpartum cardiomyopathy underwent cardiac transplantation. The patient was cooled to 34.0°C and retrograde cold blood cardioplegia was infused continuously. The cold ischemic time was 219 minutes and warm ischemic time 46 minutes. After weaning from bypass, she developed global cardiac dysfunction requiring veno-arterial extracorporeal membrane oxygenation. The circuit suddenly stopped, requiring emergency reinstitution of bypass; the circuit had clotted. Transesophageal-echocardiogram revealed thrombus within the left atrium and ventricle. There was no recovery of cardiac function and the patient developed multiorgan failure. At postmortem there was extensive myocardial infarction with evidence of widespread catastrophic intravascular red-cell sickling. This case highlights the danger of complacency in patients with SCT, offering a learning opportunity for the cardiothoracic community to highlight the most serious complication that can occur in this group of patients. We have learned that SCT and cardiac surgery is not a benign combination.

Anesthetic and Cardiopulmonary Bypass Considerations for Cardiac Surgery in Unique Pediatric Patient Populations: Sickle Cell Disease and Cold Agglutinin Disease

Physiological disturbances induced by cardiopulmonary bypass (CPB) and hypothermia during cardiac surgery are particularly pronounced in certain unique patient populations, such as patients with sickle cell disease (SCD) and cold agglutinin disease. Red blood cells containing hemoglobin S (HbS) are at increased risk of sickling under conditions encountered during cardiac surgery, leading to SCD-related complications such as vaso-occlusive events. While a target level of HbS has not been determined for patients with SCD undergoing CPB, a safe practice includes increasing the Hb level to 10 g/dL and reducing the proportion of HbS to approximately 30%. This can be accomplished through simple or exchange transfusion prior to surgery or via the modification of the CPB circuit prime. There is no clear consensus on the formulation or the delivery temperature of the cardioplegia solution necessary to prevent sickling and microvascular occlusion. The presence of cold agglutinins is another entity requiring extra vigilance for the conduct of CPB, where hypothermia can lead to activation of cold agglutinins inducing massive hemagglutination, hemolysis, microvascular thrombosis, and possibly intracoronary thrombosis. Determination of thermal amplitude is important to provide a safe reference range of temperature during surgery. High-volume plasmapheresis may be warranted to reduce cold agglutinin titers. Both warm blood cardioplegia and cold crystalloid cardioplegia above the thermal amplitude have been utilized with success.