Tuesday, October 16, 2012

Peripheral Vascular Disease and CKD

Seminars in Dialysis this month have published an excellent review of the diagnosis and treatment of peripheral vascular disease in patients with CKD. This is something that we deal with on a regular basis in the clinic and I was surprised to see that we had not dealt with this topic before on RFN. Some salient points from the article:

PVD is common in the US population and the prevalence increases with age - up to about 15% in patients over the age of 70. The prevalence of PVD in patients with CKD is far higher, one study from Italy found that 32% of patients attending a CKD clinic who were asymptomatic, had an ABI of less than 0.9 which is the traditional threshold for diagnosing PVD. Another study using NHANES data found that an eGFR of less than 60 was associated with an OR of 3.0 for PVD after full multivariable adjustment. PVD is independently associated with cardiovascular mortality and the cardiovascular risk increases as the ABI decreases. This suggests that the presence or absence of PVD could help further risk-stratify patients with moderate CKD.

Interestingly, the pathophysiology of PVD in patients with CKD (particularly those with ESRD) is different from the general population. In these patients, the primary culprit is medial calcification rather than atherosclerotic plaque formation and as a result, they often present with diffuse distal disease which is not necessarily amenable to surgical/radiological intervention. The current KDOQI guidelines recommend screening for PVD in all patients on initiation of dialysis although they do state that this guideline is not backed by much evidence and that "further research is needed". Results for primary revascularization in dialysis patients tend to be poor and there is a high rate of lower limb amputation. One issue is that dialysis patients (and those with advanced CKD) tend to have significant hardening of the arteries due to the degree of calcification and this can falsely elevate the ABI. For this reason, the authors of the review do not recommend screening of all patients with CKD and instead suggest a focused examination at each visit with a detailed history and aggressive treatment of cardiovascular risk factors. For patients who are symptomatic, an ABI followed by angiography (if refractory to medical therapy or critical ischemia) is the approach to take.

The authors have a number of nice flowcharts suggesting algorithms for the diagnosis and management of PVD in patients with CKD and I recommend giving the article a look.       

1 comment:

Darius said...

I am a medical resident on cardiology and I also wrote a few words about peripheral artery disease.