Coronary revascularization in patients with renal dysfunction

Coronary revascularization in patients with renal dysfunction

Coronary revascularization in patients with renal dysfunction: When the glomerular filtration rate (GFR) comes down below 60 ml, mortality steadily increases. Most cardiovascular disease (CVD) patients with chronic kidney disease (CKD) have multiple comorbidities and have more periprocedural complications. They also have poor long-term outcome with conservative medical management. Till now coronary artery bypass grafting (CABG) had an edge over percutaneous coronary intervention (PCI) in most studies, probably because they have multivessel disease. Those with CKD have more calcification, more diffuse disease and more complex disease. Worsening of CKD is associated with progressively increased risk of bleeding and restenosis. 30 day outcome from ACUITY trial has demonstrated this fact. Even at one year outcome CKD patients fared worse. GRACE registry showed that renal failure patients have worse outcome. Still there is some improvement with PCI compared to fibrinolysis in ST elevation myocardial infarction (STEMI), though with a higher bleeding risk. Early intervention in non ST elevation myocardial infarction (NSTEMI) with PCI showed improvement in prognosis. Renal failure patients have a higher risk of stent thrombosis. TAXUS IV trial found that target vessel revascularization (TVR) was lower with drug eluting stents (DES) vs bare metal stents (BMS), but hard endpoints were not better. There is no dosage adjustment for aspirin, clopidogrel and abciximab in renal failure. The dose of small molecular weight GP IIb/IIIa blockers have to be reduced in renal failure. Tirofiban dosage is halved. Unfractionated heparin is better than low molecular weight heparin in the setting of renal failure.

Contrast nephropathy is defined as increase in serum creatinine of more than 0.5 mg% or 25% increase from the basal level after the use of contrast, generally with 48 hours. It can be reduced by adequate saline hydration, use of iso-osmolar contrast agents and N-acetyl cysteine. Limit the contrast volume as much as possible. Beyond 140 ml is considered as a high contrast load. Estimate the creatinine clearance rather than serum creatinine levels alone.
Maximum volume of contrast permissible: [5 ml x body weight (Kg)] / serum creatinine (mg/dl)

DES with biodegradable polymer stents may be better as they might permit reduction of dual antiplatelet regimen to reduce bleeding complications.

Off pump coronary artery bypass (OPCAB) fares better compared to on pump CABG in the setting CKD in the need for renal replacement therapy.