Simultaneous Cardiac and Renal Damage in a Hypertensive Population

Cardiovascular (CV) disease is a continuum,1 where clinicians can detect 3 main stages characterized by the discovery of CV risk factors in the absence of organ damage or established disease (stage 1), by the detection of some form of target organ damage (stage 2), or by the presence of established disease (stage 3). Classical risk factors present in stage 1 are hypertension and diabetes, which are simultaneously the most frequent causes of end-stage renal disease (ESRD); high serum cholesterol levels; and smoking, which accounts for three quarters of total CV risk.2 Chronic kidney disease (CKD) constitutes an epidemic for contemporary societies and is accompanied by a significant increase in CV risk.2 CKD can be initiated as a primary renal disease, eg, chronic glomerulonephritis or polycystic kidney disease, or can develop as a form of target organ damage, through predisposing risk factors (Table). In both cases, the disease progresses through the action of the perpetuating factors seen in the Table. Predisposing and perpetuating factors for CKD are simultaneously the most important promoters of CV disease.2, 3 Detection of CKD is made by the finding of albuminuria, either microalbuminuria or macroalbuminuria, and/or by an estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m2. Further progression of CV disease is facilitated when CKD appears as a consequence of new CV risk that appear simultaneously with a decrease in renal function, eg, anemia and calcium-phosphate and vitamin D alterations.4 The finding of target organ damage (stage 2) in a hypertensive patient indicates that CV disease is more advanced and that the time to the potential presentation of a fatal or nonfatal event is shorter than it was in stage 1. In the present issue of The Journal of Clinical Hypertension, Facila and colleagues5 have investigated the relationship between CKD and CV risk in patients with left ventricular hypertrophy (LVH), detected by electrocardiographic (ECG) criteria. A total of 3962 patients were included in the study and the authors found a higher prevalence of established CV disease in patients with a depressed glomerular filtration rate (68.3% vs 54.9%, P<.001). After adjusting for age, sex, body mass index, diabetes, smoking habits, and systolic and diastolic blood pressures, the stage of renal function was an independent predictor of the presence of CV disease. The authors conclude that the determination of eGFR or estimated creatinine clearance is simple and identifies a progressive and independent increase in CV risk. In other words, the simultaneous finding of LVH and CKD is not infrequent and is characterized by an increased probability of presenting with a CV event or death in the near future. The simultaneous presence of renal and cardiac damage in hypertensive patients has been recognized in recent publications. Early abnormalities of renal function are associated with reduced coronary flow reserve probably as a consequence of an increased left ventricular mass.6 In fact, the presence of LVH is particularly prevalent in patients with CKD7 and it has been demonstrated that renal damage of any origin facilitates the development of LVH.8 A recent Italian survey has shown that ECG abnormalities (rhythm abnormalities, intraventricular conduction defects, ventricular repolarization alterations, and left-axis deviation) are independently associated with the presence of CKD and in particular microalbuminuria.9 The finding of ECG abnormalities then forces the estimation of GFR and albuminuria in order to make accurate risk stratification. Longitudinal data have proved that both LVH10 and CKD11 are independent predictors of all-cause mortality and CV morbidity. Recent data12 have shown that the simultaneous finding of LVH and CKD is accompanied by an increased incidence of coronary artery disease, stroke, and all-cause mortality. In summary, detection of target organ damage must be attempted in every hypertensive patient to complete an adequate stratification of risk. Evaluation of ECG abnormalities and an adequate estimation of renal function greatly facilitate risk stratification and the simultaneous finding of LVH and CKD constitutes a situation of particularly elevated risk that will require an optimal pharmacologic intervention.