Coronary artery disease and nuclear imaging in renal failure

[The degree of chronic renal failure is associated with the rate of pro-inflammatory cytokines, hyperhomocysteinemia and with oxidative stress]

AIM

To evaluate pro-inflammatory cytokines, homocysteinemia and markers of oxidative status in the course of chronic renal failure.

PATIENTS AND METHODS

One hundred and two patients (male/female: 38/64; age: 45±07 years) with chronic renal failure were divided into 4 groups according to the National Kidney Foundation classification. They included 28 primary stage renal failure patients, 28 moderate stage renal failure, 28 severe stage renal failure and 18 end stage renal failure. The inflammatory status was evaluated by the determination of pro-inflammatory cytokines (tumor necrosis factor-α, interleukin-1β, interleukin-6) and total homocysteine. Pro-oxidant status was assessed by assaying thiobarbituric acid reactive substances, hydroperoxides, and protein carbonyls. Antioxidant defence was performed by analysis of superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase.

RESULTS

Inflammatory markers were elevated in the end stage renal failure group compared to the other groups (P<0.001). Indeed, an increase in thiobarbituric acid reactive substances, hydroperoxides and protein carbonyls was noted in the end stage renal failure group in comparison with the other groups (P<0.001), while the levels of antioxidants enzymes activity were decreased in the study population (P<0.001).

CONCLUSION

Impaired renal function is closely associated with the elevation of inflammatory markers leading to both increased markers of oxidative stress and decreased antioxidant defense.

Patients with end-stage renal disease: optimal diagnostic and prognostic performance of myocardial gated-SPECT, initial results

PURPOSE

We investigated the role of Tc-99m sestamibi myocardial perfusion gated single photon emission computed tomography (GSPECT) in identifying those patients with end-stage renal disease (ESRD) in whom optimal diagnosis of coronary artery disease and prediction of cardiac events (CEs) could be achieved.

METHODS

This was a prospective study that included 41 asymptomatic ESRD patients who had been undergoing hemodialysis for 12 months or less (22 men and 19 women) with restricted selection criteria (asymptomatic traditional risk). Tc-99m sestamibi GSPECT was carried out for all patients, whereas coronary angiography (Cath) was carried out only for abnormal GSPECT patients, with a 2-year follow-up for CEs. Twenty individuals matched for age, sex, and BMI formed the control group.

RESULTS

Of the 41 ESRD patients, 13 showed abnormal GSPECT [11/13 with myocardial perfusion defects and left ventricular dysfunction in concordance with Cath and 2/13 with only left ventricular dysfunction (i.e. stunning)] compared with 1/20 in the control group. None of the patients with negative results experienced CEs (negative predictive value 100%); these patients had a 2-year CE-free survival rate of 100% compared with 46% for patients with positive results on GSPECT (P<0.0001; seven GSPECT-positive patients developed CEs during their follow-up). Patients with positive results were more frequently male (P<0.001), were significantly older (P=0.01), and had highly sensitive C-reactive protein levels (P=0.002). Abnormal GSPECT was the only independent predictor of CEs (95% confidence interval, 7.1-46.7; hazard ratio, 46.1; P<0.001).

CONCLUSION

GSPECT exhibited optimum performance for coronary artery disease detection and risk stratification in asymptomatic ESRD patients during their first year of regular hemodialysis who were selected according to our modification of the traditional risk category. This may help in selecting suitable candidates for Cath, revascularization, and future renal transplantation.

Clinical utility of estimated glomerular filtration rate in patients undergoing gated SPECT

BACKGROUND

Chronic kidney disease is a major risk factor for coronary artery disease (CAD). The aim of the study was to examine the association between estimated glomerular filtration rate (GFR), presence of CAD, and prognosis in patients with reversible perfusion defects at gated single-photon emission computed tomography (g-SPECT).

METHODS

Six hundred fifty-eight subjects who had undergone stress/rest g-SPECT for evaluation of myocardial ischemia were divided into two groups according to the presence of CAD, defined by a 70% diameter stenosis in at least one major vessel or principal side branch at coronary angiography.

RESULTS

GFR was lower in patients with CAD and after adjusting for several clinical characteristics through multivariate logistic regression analysis, reduced (<60 mL/min/1.73 m(2)) GFR remained a significant predictor of CAD (HR 1.80, 95% CI 1.04 to 3.12, P = .036). In addition, reduced GFR was associated with a greater extent of myocardial ischemia, assessed through the summed difference score, as well as with an increase in both total and cardiac mortality.

CONCLUSIONS

In patients with a positive g-SPECT scan, GFR is an accurate marker of CAD and is directly correlated to the extent of myocardial ischemia. Furthermore, reduced GFR had an adverse impact on survival in this particular population.