PI and RI correlated to the severity of the renal disease, as reflected by the rate of decline in reciprocal serum creatinine during antihypertensive treatment. The median RI or PI value could separate the patients into groups one of slow and another of fast progression.

The hypothesis was tested that changing the direction of the transverse gravitational stress in horizontal humans modulates cardiovascular and renal variables. On different study days, 14 healthy males were placed for 6 h in either the horizontal supine or prone position following 3 h of being supine. Eight of the subjects were in addition investigated in the horizontal left lateral position. Compared with supine, the prone position slightly increased free water clearance (349 Ϯ 38 vs. 447 Ϯ 39 ml/6 h, P ϭ 0.05) and urine output (1,387 Ϯ 55 vs. 1,533 Ϯ 52 ml/6 h, P ϭ 0.06) with no statistically significant effect on renal sodium excretion (69 Ϯ 3 vs. 76 Ϯ 5 mmol/6 h, P ϭ 0.21). Mean arterial pressure and left atrial diameter were similar comparing effects of supine with prone. The prone position induced an increase in heart rate (54 Ϯ 2 to 58 Ϯ 2 beats/min, P Ͻ 0.05), total peripheral vascular resistance (13 Ϯ 1 to 16 Ϯ 1 mmHg ⅐ min Ϫ1 ⅐ l Ϫ1 , P Ͻ 0.05), forearm venous plasma concentration of norepinephrine (97 Ϯ 9 to 123 Ϯ 16 pg/ml, P Ͻ 0.05), and atrial natriuretic peptide (49 Ϯ 4 to 79 Ϯ 12 pg/ml, P Ͻ 0.05), whereas stroke volume decreased (122 Ϯ 5 to 102 Ϯ 3 ml, P Ͻ 0.05, n ϭ 6). The left lateral position had no effect on renal variables, whereas left atrial diameter increased (32 Ϯ 1 to 35 Ϯ 1 mm, P Ͻ 0.05) and mean arterial pressure decreased (90 Ϯ 2 to mean value of 85 Ϯ 2 mmHg, P Ͻ 0.05). In conclusion, the prone position reduced stroke volume and increased sympathetic nervous activity, possibly because of mechanical compression of the thorax with slight impediment of arterial filling. The mechanisms of the slightly augmented urine output in prone position require further experimentation. blood pressure; diuresis; gravitation; natriuresis IT IS WELL KNOWN that a change in posture along the z-axis (long axis) of the human body has a pronounced effect on cardiovascular, endocrine, and renal variables (20). A 12-h posture change in humans from upright seated to 3°head-down tilt induces an increase in central blood volume with a simultaneous decrease in arterial pressures (23). Furthermore, renal sodium excretion (U Na V), urine flow rate (V), and solute free water clearance (C H2O ) increase within the initial 3-4 h of the antiorthostatic posture change, and plasma concentrations of norepinephrine (NE) and aldosterone and plasma renin activity (PRA) decrease. These effects are thought to be initiated by the increase in central blood volume through neuroendocrine reflexes. Thus a decrease in gravitational stress (G-stress) along the z-axis of the human body (G z ) leads to depletion of fluid and electrolytes.It is noteworthy that the effects of changing the G z -stress on cardiovascular, endocrine, and renal variables have been thoroughly investigated (3,20,26), whereas the effects of changing the transverse G-stress (front to back or back to front: ϮG x ; right to left or left to right: ϮG y ) in horizontal healthy humans are virtually unknown. Some investigations in this regard have been initiated as a co...

The limit of agreement between GFR(DTPA) and GFR(EDTA) are acceptable and, therefore, GFR estimated from 99mTc-DTPA renography is acceptable for clinical use in patients with reduced renal function. Furthermore, the method is simple and less time consuming compared with renal clearance techniques.

The higher daytime BP and HR as well as microalbuminuria in smokers may contribute to their increased cardiovascular risk. Furthermore, the higher ambulatory BP in smokers implicates that these patients tend to be underdiagnosed and undertreated if only clinic BP is used.

Aims Myocardial perfusion imaging with 82-rubidium positron emission tomography (82Rb-PET) is increasingly used to assess stable coronary artery disease (CAD). We aimed to evaluate the prognostic value of 82Rb-PET-derived parameters in patients with symptoms suggestive of CAD but no significant reversible or irreversible perfusion defects. Methods and results Among 3726 consecutive patients suspected of stable CAD who underwent 82Rb-PET between January 2018 and August 2020, 2175 had no regional perfusion defects. Among these patients, we studied the association of 82Rb-PET-derived parameters with a composite endpoint of all-cause mortality, hospitalization for unstable angina pectoris, acute myocardial infarction, heart failure, or ischaemic stroke. During a median follow up of 1.7 years (interquartile range 1.1–2.5 years), there were 148 endpoints. Myocardial blood flow (MBF) reserve (MFR), MBF during stress, left ventricular ejection fraction (LVEF), LVEF-reserve, heart rate reserve, and Ca score were associated with adverse outcomes. In multivariable Cox model adjusted for patient and 82Rb-PET characteristics, MFR < 2 (hazard ratio (HR) 1.75, 95% confidence interval (CI) 1.24–2.48), LVEF (HR 1.38 per 10% decrease, 95% CI 1.24–1.54), and LVEF-reserve (HR 1.19 per 5% decrease, 95% CI 1.07–1.31) were significant predictors of endpoints. Results were consistent in subgroups defined by gender, history of ischaemic heart disease, low LVEF, and atrial fibrillation. Conclusion MFR, LVEF, and LVEF-reserve derived from 82Rb-PET provide prognostic information on cardiovascular outcomes in patients with no perfusion defects. This may aid in identifying patients at risk and might provide an opportunity for preventive interventions.