You are called by the CCU nurses. They are concerned that one of a post primary angioplasty patient’s blood results has returned with platelets of 12 × 109 /L. Bloods taken at the time of procedure revealed platelets of 179 × 109 /L. The patient has no signs of bleeding and all other blood results, including haemoglobin, are stable and consistent. They have been loaded with aspirin 300 mg, prasugrel 60 mg, heparin 8000 units, and abciximab as a weight-adjusted bolus and current infusion for 12 hours. They had not previously received these agents. GP 2b/3a was recommended as the patient had a highly thrombotic right coronary artery occlusion with evidence of microvascular distal embolization and required a long length of drug-eluting stent.
What do you advise?
Inadequate platelet inhibition or platelet replacement will increase the chances of early stent thrombosis and should be avoided. This clinical scenario suggests an early immune-mediated response to abciximab with thrombocytopenia. The platelet count should gradually recover on stopping the agent, but the platelets should not be replaced unless there were signs of significant bleeding. Heparin-induced thrombocytopenia usually occurs after a few days with repeated exposure. Pseudo-thrombocytopenia (clumping) is possible and would be obvious on a blood film, but this should be excluded rather than assumed.
A patient arrives directly in the catheterization laboratory for primary angioplasty. They volunteer a previous serious allergic reaction to heparin called ‘HIT’ as you are consenting them.
What would be your anticoagulation strategy?
Bivalarudin is a direct thrombin inhibitor and a safe alternative in a patient with previous heparin-induced thrombocytopenia (HIT). The Horizons-AMI trial suggested a significant reduction in all-cause mortality and major bleeding compared with the combination of UFH and GP2b/3a in primary angioplasty patients. Fondaparinux is a synthetic inhibitor of factor Xa and has been shown not to be inferior to LMWH in ACS, with halved major bleeding (OASIS-5 trial).
You review a patient in clinic who has previously had bypass surgery and a recurrence of angina. They have three grafts (LIMA to LAD, vein graft to OM, and vein graft to RCA). You recommend a coronary angiogram. The patient asks you if the procedure will be carried out from the wrist or the leg as they have had vascular procedure to both groins. You can see bilateral inguinal scars, but the procedures were carried out at another hospital.
Although, based on the vascular procedure, it is often possible to access the femoral arteries, this is obviously best avoided as there is a greater risk of complications. The left radial will give direct access to the LIMA (comes off the left subclavian artery) and would be the route of choice. The right radial will not allow simple or safe access to the left subclavian artery. If the left radial has been harvested as a graft, then the femoral arteries may have to be considered.
Which of the following statements is true regarding non-ST elevation acute coronary syndromes (NSTE-ACS) compared with ST elevation myocardial infarctions (STEMI)?
NSTE-ACS is more frequent with older patients and more comorbidity. Mortality of NSTE-ACS is initially lower, but equal at 6 months and higher in the long term.
On your ward round you review a patient who is 48 hours post anterior STEMI treated successfully with primary angioplasty. He has type 2 diabetes and hypertension. He is gradually improving, having initially suffered with heart failure. He still feels ‘chesty’ and auscultation reveals minimal basal crepitations. Echocardiography has revealed an ejection fraction of 40%. Blood pressure is 110/70 mmHg with heart rate 55 bpm at rest. Ramipril has been titrated to 2.5 mg bd with bisoprolol 2.5mg od. U&Es have remained normal.
How would you improve his medical treatment?
Aldosterone antagonists are indicated if EF ≤ 40% (EPHESUS trial) or if there is heart failure or diabetes, provided that there is no renal failure or hyperkalaemia. The diuretic action should help with the mild residual congestion. Blood pressure will appear to limit further titration of the ACE inhibitor at this stage.