Polycythaemia rubra vera (PRV) is a chronic myeloproliferative disease characterized by excessive red blood cell production and in 50% of patients proliferation of all cell lines (i.e. thrombocytosis and leucocytosis). It is more common in men [1] with a prevalence of 4-16 per million [2]. PRV can cause both bleeding and thrombosis in the same patient [3]. Quantitative platelet derangement plays a role in the development of thrombosis and ischemia which leads to increased incidence of stroke, myocardial infarction and arterial or venous thrombosis [4]. Platelet abnormalities may also predispose patients to bleeding at virtually any site [2]. Myocardial infarction and sudden death are complications of newly diagnosed and untreated PRV, most often in the people >65 years old with underlying coronary artery disease [2].
The accepted treatment for acute myocardial infarction in patients with PRV is based on exchange phlebotomy and platelet pharesis [2]. Routine therapy such as aspirin, heparin, low molecular weight heparin and thrombolysis is still not clear [2]. Some authors have reported the use of oral anticoagulants with aspirin and clopidegrol as a means to prevent thrombosis in such patients [5]. Acceleration of atherosclerosis and thrombosis has been shown to occur as a complication of PRV [1]. Coronary artery bypass graft (CABG) surgery, in turn, has been performed very rarely in the setting of PRV [5]-[7]. One interesting finding in these reported cases is that the long term outcome for such patients is good in terms of clinical outcome and angiographic patency of the coronary grafts. Our case remained well 2 years later with no recurrence of angina.
The main perioperative concern with patients with PRV undergoing CABG is twofold. The first is the increased risk of graft thrombosis compared to normal population due to hyperviscosity [8] and the second is their increased risk of bleeding following cardiopulmonary bypass. The management of the increased thrombosis risk depends on adequate anticoagulation in such patients including a combination of antiplatelet agents (e.g. aspirin and clopidegrol) with addition of anticoagulants [5, 8], either orally (such as warfarin) or subcutaneously/intravenously (such as low molecular weight heparin/unfractionated heparin). Such management remains largely unknown, however, few reported cases have shown the success of such combination therapy [5]. The second main problem of bleeding tendency requires a dual control of polycythaemia disease process (through the use of cytoreductive therapy or exchange phlebotomy) and the adequate control of any coagulation derangements. Various polycythaemia medications have been used in varying time postoperatively following CABG (including hydroxyurea [5] and 32 P [7]. However, the exact timing of instituting these therapies in the postoperative course is unknown but assumed to be better in the immediate postoperative period [5, 7].
The spectrum of complications observed in our patient (i.e. hemorrhagic pleural effusion, acute renal failure with reactive thrombocytosis) responded well to increased dose of cytoreductive therapy (hydroxyurea) and combination of antiplatelet agents (aspirin and persantin) with low molecular weight heparin. We did not have to resort to oral anticoagulation partly because of the increased risk of bleeding in a PRV patient who has already developed hemorrhagic effusion. Although we started hydroxyurea medication to our patient on the 4th postoperative day (based on recommendation by a haematologist), we believe that earlier commencement of such medication might have prevented some of the observed complication in our patient. We believe that cases such as ours should have hydroxyurea commenced on day one and escalated in dosage according to clinical outcome.
