Editorial Comment

Bad Kidneys are Bad for theHeart: But What Can We DoAbout It?

Timothy D. Henry,1* MD and Charles A. Herzog,2,3MD

1Minneapolis Heart Institute Foundation, AbbottNorthwestern Hospital, Minneapolis, Minnesota2Hennepin County Medical Center, University of Min-nesota, Minneapolis, Minnesota3Cardiovascular Special Studies Center, UnitedStates Renal Data System, Minneapolis, Minnesota

Chronic kidney disease (CKD) is a major risk factorin patients with cardiovascular disease [1–3]. Patientswith CKD who present with acute coronary syndromes,or undergo revascularization with either percutaneouscoronary intervention (PCI) or coronary artery bypassgraft surgery (CABG) have increased mortality. Patientswith end-stage renal disease (ESRD) on dialysis are atparticularly high risk.

In this issue of CCI, Parikh et al. report the in-hos-pital mortality on 25,018 patients undergoing PCI overa 4-year period at four New York state hospitals,stratified by renal function [4]. Nearly 30% of patientshad moderate CKD (estimated glomerular filtrationrate (eGFR) �60) (26.4%) or ESRD on dialysis(1.9%). All-cause in-hospital mortality was markedlyhigher in patients with ESRD (2.1%) and moderateCKD (1.3%) versus patients with preserved renal func-tion (0.3%). The results confirm previously reporteddata that patients with either CKD or ESRD have highrisk characteristics including age, higher rates of priorcoronary revascularization, peripheral arterial disease,previous stroke, congestive heart failure, and diabetes.These patients also have more complex coronary anat-omy including calcification and diffuse disease [5].Importantly, they are also less likely to receive guide-line recommended therapy including antiplateletagents, anticoagulants, and revascularization [6]. Inthis registry, they were less likely to receive drug-eluting stents even though they are at higher risk forrestenosis.

The authors concentrated on in-hospital mortality intheir report, but the real clinical issue is what happensafter the patient leaves the hospital, a problem notrestricted to PCI [7,8]. Long-term mortality for ESRD

remains extremely high in a wide spectrum of cardio-vascular disease (Figure 1). In 2009, there wereapproximately 399,000 dialysis patients. The overallmortality rate in 2009 for US dialysis patients was 200deaths/1,000 patient years. The five-year mortality ofdialysis patients has improved over time, but it remainsdepressingly high: 66% for a patient starting dialysis in2004. In contrast, the five-year mortality for renaltransplant recipients was 27% for the same time period[9]. Approximately, 45% of the mortality in dialysispatients is attributed to a cardiovascular etiology.About 14% of cardiac deaths are ascribed to acutemyocardial infarction; 66% of cardiac deaths (or 26%of all-cause mortality) are attributed to arrhythmicmechanisms [9]. Patients with ESRD are particularlyvulnerable to sudden cardiac death: the combination ofobstructive coronary artery disease, left ventricular hy-pertrophy (at least 75% of dialysis patients), myocar-dial fibrosis, autonomic dysfunction (including obstruc-tive sleep apnea), and microvascular dysfunction inpatients with diabetes places the ESRD patient atheightened risk for sudden death. Coronary revasculari-zation does not nullify the risk: even after surgical re-vascularization with a left internal mammary graft, thetwo-year mortality of dialysis patients is 43% [10].

Other adverse outcomes such as readmission, revas-cularization, myocardial infarction, and bleeding are allmarkedly higher in these patients as well. The authorsdiscuss the myriad of potential reasons for theincreased risk but the solution remains elusive.

As the prevalence of diabetes increases and the pop-ulation ages, the number of patients with CKD willcontinue to increase. Nearly, one-third of the patientsin this report had a eGFR <60. CKD presents a majorpublic health challenge in the US and abroad. It isestimated that about 12% of the US population (25million) have CKD, but even more importantly from

Conflict of interest: Nothing to report.

*Correspondence to: Timothy D. Henry, Minneapolis Heart Institute

Foundation, 920 East 28th Street, Suite 300, Minneapolis, MN

55407. E-mail: henry003@umn.edu

Received 16 July 2012; Revision accepted 16 July 2012

DOI 10.1002/ccd.24567

Published online 8 August 2012 in Wiley Online Library

(wileyonlinelibrary.com).

' 2012 Wiley Periodicals, Inc.

Catheterization and Cardiovascular Interventions 80:358–360 (2012)

an interventional cardiology perspective, 40% or moreof people over age 70 have CKD [11]. The cardiologyworld has become ‘‘comfortable’’ with CKD stagesand the concept of eGFR <60 as a ‘‘threshold ofrisk’’ but a single dichotomous cutpoint is actually adull discriminator. A more accurate and comprehensiverisk-based CKD staging system which takes intoaccount both eGFR and ranges of proteinuria will takeits place in the near future [11].

So, bad kidneys are bad for the heart, but what canwe do about it? While earlier detection and subsequentprevention of CKD is clearly desirable, we suspect thiswill continue to be a major challenge. Clinical trialsdesigned specifically to address patients with CKD andESRD are sorely needed. Perhaps the best approachfor interventional cardiologists is to focus on the useof appropriate guideline-based medications and revas-cularization. This is not so simple as these patients areat increased risk for bleeding and are more likely topresent with atypical symptoms. The ideal method ofreperfusion in these patients also remains controversial.There are limited randomized clinical trials and it isextremely challenging to have comparable groups inregistries such as this [8]. Frequently, CKD and partic-ularly ESRD patients are not candidates for surgicalrevascularization. Reflecting this issue, patients in thisregistry with ESRD and CKD had higher rates of

intervention on bypass grafts, the LAD, and the leftmain than patients with normal renal function.

In summary, CKD is increasingly common and amajor risk factor for adverse outcomes in all cardio-vascular disease. An ongoing focus on prevention, clin-ical trials designed specifically for CKD and ESRD,use of guideline recommended therapies including re-vascularization and careful clinical follow-up remainour best hope to address this growing challenge.

REFERENCES

1. Collins AJ, Foley R, Herzog C, Chavers B, Gilbertson D, Ishani

A, Kasiske B, Liu J, Mau LW, McBean M, Murray A, St Peter

W, Xue J, Fan Q, Guo H, Li Q, Li S, Li S, Peng Y, Qiu Y,

Roberts T, Skeans M, Snyder J, Solid C, Wang C, Weinhandl E,

Zaun D, Zhang R, Arko C, Chen SC, Dalleska F, Daniels F,

Dunning S, Ebben J, Frazier E, Hanzlik C, Johnson R, Sheets D,

Wang X, Forrest B, Constantini E, Everson S, Eggers P, Agodoa

L. Excerpts from the United States Renal Data System 2007 an-

nual data report. Am J Kidney Dis 2008;51:S1–S320.

2. Go AS, Chertow GM, Fan D, McCulloch CE, Hsu CY. Chronic

kidney disease and the risks of death, cardiovascular events, and

hospitalization. N Engl J Med 2004,351:1296–1305.

3. Osten MD, Ivanov J, Eichhofer J, Seidelin PH, Ross JR, Barolet

A, Horlick EM, Ing D, Schwartz L, Mackie K, Dzavı́k V.

Impact of renal insufficiency on angiographic, procedural, and

in-hospital outcomes following percutaneous coronary interven-

tion. Am J Cardiol 2008;101:780–785.

Fig. 1. January 1, 2005 point prevalent ESRD patients, age 20 and older, with a first cardiovascular diagnosis or procedure in2005–2007. Modified from USRDS 2009 ADR.

Catheterization and Cardiovascular Interventions DOI 10.1002/ccd.Published on behalf of The Society for Cardiovascular Angiography and Interventions (SCAI).

Bad Kidneys Are Bad for the Heart 359

4. Parkih PB, Jeremias A, Naidu SS, Brener SJ, Lima F, Sholfmitz

RA, Pappas T, Marzo KP, Grubert L. Impact of severity of renal

disfunction on determinants of in-hospital morality among

patients undergoing percutaneous coronary intervention. Catheter

Cardiovasc Interv 2012;DOI 10.1002/ccd.23394.

5. Gruberg L, Rai P, Mintz GS, Canos D, Pinnow E, Satler LF,

Pichard AD, Kent KM, Laird JR Jr, Lindsay J Jr, Waksman R,

Weissman NJ. Impact of renal function on coronary plaque mor-

phology and morphometry in patients with chronic renal insuffi-

ciency as determined by intravascular ultrasound volumetric anal-

ysis. Am J Cardiol 2005;96:892–896.

6. Tsai TT, Maddox TM, Roe MT, Dai D, Alexander KP, Ho PM,

Messenger JC, Nallamothu BK, Peterson ED, Rumsfeld JS. Contra-

indicated medication use in dialysis patients undergoing percutaneous

coronary intervention. JAMA 2009;302:2458–2464.

7. Herzog CA, Ma JZ, Collins AJ. Poor long-term survival after

acute myocardial infarction among patients on long-term dialy-

sis. N Engl J Med 1998,339:799–805.

8. Herzog CA, Ma JZ, Collins AJ. Comparative survival of dialysis

patients in the United States after coronary angioplasty, coronary

artery stenting, and coronary artery bypass surgery and impact

of diabetes. Circulation 2002;106:2207–2211.

9. United States Renal Data System 2011 Annual Data Report:

Atlas of Chronic Kidney Disease and End-Stage Renal Disease

in the United States. Bethesda, MD: National Institutes of

Health, National Institute of Diabetes and Digestive and Kidney

Diseases, 2011. http://www.usrds.org/. Accessed July 13, 2012.

10. Herzog CA, Strief JW, Collins AJ, Gilbertson DT. Cause-specific

mortality of dialysis patients after coronary revascularization:

Why don’t dialysis patients have better survival after coronary

intervention? Nephrol Dial Transplant 2008;23:2629–2633.

11. Levey AS, de Jong PE, Coresh J, El Nahas M, Astor BC, Mat-

sushita K, Gansevoort RT, Kasiske BL, Eckardt KU. The defini-

tion, classification, and prognosis of chronic kidney disease: A

KDIGO Controversies Conference report. Kidney Int 2011;

80:17–28.

Catheterization and Cardiovascular Interventions DOI 10.1002/ccd.Published on behalf of The Society for Cardiovascular Angiography and Interventions (SCAI).

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