Sunday, December 20, 2009

Cardiovascular Complications of Kidney Disease

Question: Who is the most important medical subspecialist for a patient with CKD to have regular contact with? Is it the nephrologist? A case could be made, relying purely on mortality statistics, that it's actually the cardiologist. CKD/ESRD leads to a wide range of cardiovascular complications. A quick review:

1. Hypertension: it is rare to find the ESRD patient WITHOUT hypertension. Along with a high rate of essential hypertension afflicted the general Western population, ESRD patients are at the additional disadvantage of having to deal with hypervolemia and sodium retention, which can made BP very difficult to control. Common ESRD medications such as EPO is also associated with high blood pressure, as is secondary hyperparathyroidism.

2. CHF: Both systolic and diastolic dysfunction are commonly associated with CKD/ESRD; in particular, there is a very high rate of LVH (both concentric and eccentric LVH). Furthermore, patients with AV fistulas or severe anemia can develop high output CHF.

3. CAD: CAD is exceptionally high in the CKD/ESRD population, though the mechanism of cardiac ischemia is posited by some to be discretely different from the standard "rupture of an atherosclerotic plaque" model which has been studied primarily in non-CKD/ESRD populations. Although serum troponin levels may be slightly elevated in CKD/ESRD patients simply because it is cleared less efficiently, even small elevations of cardiac troponins in these patients are associated with poor outcomes. Many hypotheses have been put forth regarding the increased CV risk associated with dialysis; the currently favored ones include abnormal calcium-phosphate metabolism, chronic inflammatory state, dyslipidemias, the accumulation of hypothetical cardio-toxic uremic toxins, and the high rate of association between CKD and diabetes.

4. Arrhythmias/Sudden Cardiac Death: The dialysis unit is a great place to uncover underlying EP abnormalities: there are non-physiologic fluid shifts, rapid changes in electrolyte concentrations, and the patient is being closely monitored.

5. Pericardial Effusions: Both uremia and dialysis itself can be associated with pericardial effusion. Main intervention: intensify dialysis.

6. Valvular Abnormalities: in particular, valvular calcifications can result from abnormal calcium/phosphate metabolism. These patients tend to do poorly with valvuloplasty procedures.

7. Pulmonary Hypertension: it is important to be aware of pulmonary hypertension in the patient with CKD/ESRD as it may make the patient ineligible for renal transplantation if it is too severe.


Anonymous said...

Oh, get real. Remember your experience dealing with "Outside Hospital."

Your job as a nephrologist is to keep the patient away from the cardiologist and his dye and atheroembolic inducing caths.

The next cardiologist I see who can properly manage hypertension will be the first.

Anonymous said...

I agree with anonymous
Lately I have been getting consults for HTN from CARDIOLOGISTS?
This is really funny I think!
But what the heck, I feel we can manage CHF as well.

nathanhellman said...

To clarify: my point in the opening paragraph was more to state the importance of cardiovascular morbidity & mortality in the patient with CKD/ESRD than to comment on the need for patients to have a cardiologist to manage these complications. But your points are well-taken.

uk_trainee said...

I feel the role of the dialysis procedure itself is under-recognized. One of the unfortunate effects of the NCDS study was it led to nephrologists thinking only small solute clearance matters and ultrafiltration volumes and rates don't. Kt/V could be achieved using larger dialysers in shorter times and this likely contributes to CV morbidity as summarised in this review