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.......................................................................................................... 3.4.8.6 Laboratory precautions

• Coagulation parameters: plasma volume is reduced due to secondary erythrocytosis; the amount of sodium citrate must be adjusted to haematocrit if haematocrit is >55%. • Haematocrit determined with automated electronic particle counts (micro-haematocrit centrifugation) results in falsely high haematocrit due to plasma trapping. • Glucose level can be reduced (increased in vitro glycolysis, which results from the increased number of erythrocytes). 3.4.8.7 Indications for intervention Risk and benefit must be carefully considered and require expertise. Cyanotic patients without PAH/Eisenmenger syndrome must be periodically evaluated for any procedure that may improve quality of life and reduce morbidity, or for eligibility for physiological repair (see section 4.15).

3.4.8.8 Medical therapy • Specific PAH treatment: see section 3.4.3. • Arrhythmias: sinus rhythm should be maintained whenever possible. Antiarrhythmic therapy must be individualized (medications, ablation, epicardial PM/ICD). Antiarrhythmic therapy is extremely difficult; drug therapy should be initiated with particular care and generally in a hospital. • Therapeutic phlebotomy should only be performed in the presence of moderate/severe hyperviscosity symptoms due to secondary erythrocytosis (haematocrit at least >65%), in the absence of dehydration and iron deficiency.82 Isovolumetric fluid replacement (7501000 mL of isotonic saline while removing 400500 mL of blood) should be undertaken. • Blood transfusion may be required in the presence of ironreplete anaemia (haemoglobin inadequate to oxygen saturation) and should not be based on conventional indications. • Iron supplementation should be performed in the presence of iron deficiency (MCV <80 fL, low iron stores) and carefully followed (rebound effect). • Routine anticoagulation/aspirin: currently available data do not support any benefit in cyanotic patients to prevent thromboembolic complications. There is, however, an increased risk of bleeding. • Indication for anticoagulation: atrial flutter/AF (target INR 22.5; higher target INR in the presence of other risk factors). Note laboratory precautions: false high INR values are measured due to the high haematocrit. There are no data and only anecdotal experiences about the use of NOACs (see also section 3.4.7). • Haemoptysis: requires chest computed tomography if there is an infiltrate on the chest X-ray. Bronchoscopy puts the patient at risk and seldom provides useful information. Therapy includes discontinuation of aspirin, non-steroidal anti-inflammatory agents, oral anticoagulants; treatment of hypovolaemia and anaemia; reduction of physical activity; and suppression of nonproductive cough. Selective embolization of bronchial arteries may be required for refractory intrapulmonary haemorrhage/ haemoptysis. Antifibrinolytic agents (e.g. inhaled tranexamic acid) are under investigation and may be a novel approach to treat haemoptysis.103 More trials are needed. • Hyperuricaemia: no indication to treat asymptomatic hyperuricaemia. • Acute gouty arthritis (atypical presentation) is treated with oral or intravenous colchicine, probenecid, and anti-inflammatory drugs, with attention paid to the risk of renal failure and bleeding. Uricosuric (e.g. probenecid) or uricostatic agents (e.g. allopurinol) avoid recurrence.

3.4.8.9 Follow-up recommendations All cyanotic patients require lifelong evaluation with follow-up visits every 612 months in a specialized ACHD centre in close collaboration with the family physician. Evaluation includes:

Table 9 Risk reduction strategies in patients with cyanotic congenital heart disease

Prophylactic measures are the mainstay of care to avoid complications.83 The following exposures/activities should be avoided: Other risk reduction strategies include: • Pregnancy in patients with Eisenmenger syndrome and in cyanotic

patients without PAH, but arterial oxygen saturation <90% • Use of an air filter in an intravenous line to prevent air embolism

• Iron deficiency and anaemia (no routine, inappropriate phlebotomies

to maintain a pre-determined haemoglobin)  treat iron deficiency and iron-deficient anaemia • Consultation with an ACHD cardiologist before administration of any agent

and performance of any surgical/interventional procedure

• Inappropriate anticoagulation • Prompt antibiotic therapy of upper respiratory tract infections • Dehydration • Cautious use or avoidance of agents that impair renal function • Infectious disease: administer influenza and pneumococcal vaccines • Contraceptive advice at each clinic visit • Cigarette smoking, recreational drug abuse including excessive alcohol • Transvenous PM/ICD leads • Strenuous exercise • Acute exposure to heat (sauna, hot tub, or hot shower) or extreme cold • Oestrogen-containing contraception CHD = congenital heart disease; ICD = implantable cardioverter defibrillator; PAH = pulmonary arterial hypertension; PM = pacemaker. Downloaded from academic.oup.com/eurheartj/article/42/6/563/5898606 by guest on 07 October 2026