A COVID-19 patient with recurrent acute limb ischaemia despite two successive types of therapeutic dose anticoagulation and thrombolysis

COVID-19 is caused by the SARS-CoV-2, and its presentation ranges from mild upper respiratory illness to critical disease including acute respiratory distress syndrome and multiorgan dysfunction. While it was initially believed to primarily target the respiratory system, numerous studies have demonstrated it to cause a hypercoagulable state that predisposes to arterial and venous thrombosis. We present a case where a patient with COVID-19 developed acute lower limb ischaemia due to arterial thrombosis in the setting of full-dose enoxaparin, followed by heparin infusion protocol. The patient developed recurrent ischaemia despite thrombolysis in addition to anticoagulation, and eventually required open thrombectomy before making a full recovery.

Insights into the role of thrombin in the pathogenesis of recurrent ischaemia after acute coronary syndrome

SummaryAcute coronary syndrome (ACS) is a medical emergency. Patients who survive the initial event remain at risk of recurrent cardiovascular events. In most cases, ACS is triggered by thrombosis after rupture of an atherosclerotic plaque. Key to thrombus formation at this site is the generation of thrombin, which not only converts fibrinogen to fibrin but also serves as a potent platelet agonist and induces platelet aggregation at the site of vascular injury. Although dual antiplatelet therapy is more effective for the prevention of recurrent events than aspirin alone after ACS, there remains an approximately 10 % risk of recurrent ischaemic events at one year. Recent studies have evaluated whether the addition of an anticoagulant to antiplatelet therapy reduces the risk of recurrent ischaemia after an ACS event. Rivaroxaban, an oral factor Xa inhibitor, attenuates thrombin generation. When used in conjunction with dual antiplatelet therapy in patients with stabilised ACS, rivaroxaban 2.5 mg twice daily significantly reduced the risk of the composite endpoint of cardiovascular death, myocardial infarction and stroke compared with placebo. Although it increased the risk of bleeding, rivaroxaban was associated with a reduction in mortality; a finding that supports the use of a dual-pathway approach that combines anticoagulant and antiplatelet therapy. This review explores the pathophysiology of ACS to provide perspective on the results of recent clinical trials with novel oral anticoagulants for ACS and to identify their potential role in this setting.

Routine management after percutaneous coronary intervention

Following a technically successful procedure, it is the post-procedural care of the patient that will often dictate both short- and long-term outcomes. Post-procedural care involves close monitoring of the patient for early complications, which may be secondary to the procedure itself or the presenting complaint. Immediate complications following percutaneous coronary intervention (PCI) may occur due to bleeding, most commonly at the access site, or due to early cardiac complications, often related to technical issues during the procedure. Non-cardiac complications, such as the development of contrast nephropathy, will become apparent in the hours or days following the initial procedure. Prompt and accurate identification of post-procedural complications is essential if they are to be managed effectively, and identification of the ‘at risk’ patient may also facilitate early identification of problems when they do occur. Complication rates are higher in patients with acute coronary syndromes, often exacerbated by aggressive antithrombotic regimens, and also in older patients with comorbid conditions. The type of care and length of stay will also vary according to the clinical context and needs to be carefully considered once the PCI has been performed. Following discharge, the longer-term management of residual coronary disease and recurrent ischaemia along with appropriate secondary prevention may all affect longer-term outcome. This chapter will examine the issues surrounding the immediate and longer-term care of the patient following PCI.

No-reflow

The no-reflow phenomenon is associated with significant cardiac consequences: poor functional recovery, ongoing or recurrent ischaemia, and increased short-term mortality. It occurs rarely in elective percutaneous interventions, but far more frequently in patients who present with acute myocardial infarction (AMI). It is in these patients, where primary percutaneous coronary intervention (PPCI) has become the gold standard that has most recently highlighted the phenomenon as it is commonly visualized in real time by the interventional cardiologist.