P744 The main influencing factors of cardiac adaptation effecting the diastolic and right ventricular function in peripubertic athletes

Introduction

Several studies examined the effects of regular training in peripubertic athletes’ heart, focusing on the left ventricle (LV). Their normal LV values are showing significant differences from adult athletes. In contrast, there are no specific normal ranges of the diastolic function and the right ventricular (RV) parameters in this age group. Moreover, the results of the latest studies are inconsistent through the different inclusion criteria and influencing factors.

Purpose, methods: The purpose of our study was to examine the specific diastolic and RV parameters of peripubertic athletes and compare them to the available normal values of adult athletes or healthy age-matched non-athletes. Furthermore, we were looking for the effects of the main influencing factors [lean body mass (LBM), body surface area (BSA), age, gender, training time, sporting discipline] on the echocardiographic parameters. 146 children and young adults (athletes, triathletes, basketball players, soccer players) were included between the age of 9 and 20 years (119 males, 27 females, 16,1 ±2,55 years). Specific 2D and tissue Doppler echocardiographic examinations were performed with one-lead continuous ECG gating.

Results

Examining the LV we did not find any significant differences comparing to the latest normal LV values by age. Significant positive correlation was found between the LV parameters, age and LBM. In comparison to adult athletes’ diastolic parameters, significantly (p< 0,001) higher E, lower A values and higher E/A ratio was detected. However, we found significantly (p< 0,001) higher lateral, septal and average e’ values and significantly (p< 0,001) lower E/e’ ratio compared to both reference groups. Therefore, the supernormal diastolic values of our athletes exceeded not only the diastolic performance of the age-matched non-athletes but also the adult professionals. Moreover, significantly (p< 0,001) lower structural and functional RV parameters were detected in the young athletes than the adult ones. In comparison to the peripubertic non-athletes significantly (p< 0,001) higher structural parameters, higher tricuspid S wave, RV end-diastolic and end-systolic area values were found. Contrary, there was no differences between the tricuspid annular plan excursion (TAPSE) values. Based on multivariate analysis we found remarkable correlation (r= 0,527, p< 0,001) between the diastolic or RV parameters and the common effect of the main influencing factors: LBM, BSA, age and training time.

Conclusion

There are no clearly defined normal values of diastolic and RV parameters in peripubertic athletes, however we also detected remarkable left and right ventricular changes in this young age group. Well-defined cut-off values should be applied to differentiate pathological conditions. The main influencing factors of the echocardiographic parameters are LBM, BSA, age and training time having additive effects on the cardiac adaptation.

P1539Aortic pulse wave velocity measured by an oscillometric device independently predicts all-cause mortality in a cohort of 4146 subjects

Objectives

Assessment of carotid-femoral pulse wave velocity by applanation tonometry independently predicts all-cause and cardiovascular mortality. However, there has been a need for a simpler, user-independent measurement with a validated device, that is applicable even in the primary care setting.

Methods and subjects

4146 subjects (49% men) aged 35–75 years were measured in multiple centers in Hungary. Subjects visited the outpatient department of these centers on their own initiative. The measurement of aortic pulse wave velocity (PWVao) with Arteriograph was performed in addition to taking past medical history, physical examination and laboratory tests. The mean follow-up time of the study was 5.5 years. The number of events (all cause mortality) were provided by the Hungarian National Health Insurance Fund. Cox regression analyses were used to identify predictive factors for this endpoint.

Results

The mean age of the study population was 53 years, brachial systolic and diastolic blood pressure were 137±20 and 82±11 mmHg, and heart rate was 70±10 1/min. The mean value of SCORE was 3 in this large cohort. 410 subjects had a registered cerebro-or cardiovascular event before the measurement, the number of smokers was 656 (16%), 1974 subjects were treated with at least one anti-hypertensive drug (48%), while the number of subjects on lipid-lowering, antidiabetic or antiplatelet medication were 807 (19%), 352 (8%) and 398 (17%), respectively. There were 116 fatal events during a mean follow-up of 5.5 years. According to the Cox regression, PWVao is a significant and independent predictor of all cause-mortality and in univariate analysis, a 1.0 m/s increase in PWVao was associated with HR 1.7 [1.47–1.98; p<0.001], for this endpoint.

Conclusion

Aortic pulse wave velocity measured by an invasively validated, simple, oscillometric device predicted all-cause mortality in a large cohort of relatively young subjects of the general population that may improve risk stratification even in the everyday clinical practice or primary care setting.

Quantification of pulmonary capillary endothelium-bound angiotensin converting enzyme inhibition in man

Angiotensin converting enzyme (ACE, kininase II) is an endothelial luminal ectoenzyme expressed abundantly on the pulmonary capillary endothelium and recognized as the site for the conversion of circulating angiotensin I to II. In the present study, we have applied recently developed methodologies for assaying pulmonary capillary endothelium-bound (PCEB) ACE activity in man, to estimate the interaction of an ACE inhibitor (enalaprilat) with PCEB ACE in human subjects. Trace amounts of the specific ACE substrate, 3H-benzoyl-Phe-Ala-Pro (3H-BPAP; 40 Ci or 2 nmol), was injected as a bolus into the subclavian vein and immediately blood was withdrawn from a radial arterial catheter. Plasma concentrations of surviving substrate and product (3H-benzoyl-Phe) were estimated and BPAP utilization was calculated during a single transpulmonary passage, at baseline (T(0)) and at 15 min (T(15)) and 2 h (T(120)) after intravenous administration of 1.5 g/kg enalaprilat in 12 normotensive subjects. This treatment had no significant effect on mean arterial pressure (91+/- 6 vs. 84 +/- 7 vs. 88 +/- 6 mm Hg for T(0), T(15) and T(120), respectively), but significantly decreased serum and PCEB ACE activities. When normalized to predrug (T(0)) activity levels, enalaprilat inhibited PCEB and serum ACE activities at T(15) 74 +/- 6% and 68 +/- 6%, respectively. However, 2 h after enalaprilat (T(120)), PCEB ACE inhibition was maintained at 66 +/- 7%, whereas serum ACE inhibition was reduced to 46 +/- 8% (P<.01 from PCEB ACE), suggesting a preferential PCEB ACE inhibitory effect of enalaprilat.

Effect of acute coronary occlusion on the size of the dynamically perfused coronary capillary bed in the dog

The aim of the present study was to investigate the influence of reduced left anterior descending (LAD) coronary arterial blood flow on the size of the perfused coronary capillary surface area (CCSA) in dogs. The transcoronary hydrolysis (v) of the specific ACE substrate, [3H]benzoyl-Phe-Ala-Pro, was estimated and the parameter Amax/Km (proportional to the size of the perfused CCSA) was calculated. By means of a ligature placed around the LAD, LAD blood flow was transiently reduced to 36.0 +/- 4.1 (E1) and 17.4 +/- 4.3% (E2) of control; in a separate maneuver the first diagonal branch of the LAD was ligated to achieve 40.0 +/- 6.7% (E3) of control flow. The v values remained unchanged at around 0.7 for E1, E2, and E3 determinations, suggesting unaltered substrate transit time through the coronary capillary bed. Amax/Km values decreased to 36 +/- 5, 17 +/- 4, and 47 +/- 10% of control for E1, E2, and E3 determinations, respectively, reflecting a flow-proportional decrease in CCSA. Values of the transpulmonary measures of v and Amax/Km performed at the beginning and end of the protocol were unchanged. These results support the hypothesis that reduction in coronary blood flow will produce proportional decreases in the size of the CCSA. This new procedure can thus serve as a useful tool for investigating alterations in the size of the CCSA in different species and under various pathophysiologic challenges.

Unaltered pulmonary capillary surface area in the presence of changing arterial resistance

We hypothesized that capillary recruitment may not be solely dependent on extracapillary factors. To test this hypothesis, rabbits were anesthetized and placed on total cardiac bypass at a constant, physiological pulmonary blood flow. Vascular occlusion techniques were combined with measurement of the transpulmonary metabolism of an angiotensin-converting enzyme substrate, allowing the concomitant assessment of changes in segmental resistances and dynamically perfused capillary surface area. Intra-arterial serotonin infusion increased upstream pulmonary vascular resistances without affecting dynamically perfused capillary surface area. Intra-arterial isoproterenol infusion diminished serotonin-induced increased upstream resistances, also without affecting capillary surface area. These findings support the hypothesis that pulmonary capillary recruitment may not be solely dependent on extracapillary factors.

cGMP accumulation and gene expression of soluble guanylate cyclase in human vascular tissue

Gene expression of soluble guanylate cyclase (sGC) and cGMP accumulation in response to sodium nitroprusside (SNP) were studied in cultured human vascular cells and freshly harvested vascular tissue. As revealed by reverse transcriptase-polymerase chain reaction, cultured smooth muscle and endothelial cells, as well as freshly isolated human vascular tissue, express mRNA for the alpha 3 and beta 3 subunits but not for the alpha 2 and beta 3 subunits is evident even in the absence of increased cGMP accumulation in response to SNP. cGMP accumulation in human cells cultured from different vascular beds typically increased two- to five-fold (maximum of 11.4-fold) over baseline following stimulation with 100 microM SNP. Bovine, murine, canine, and avian vascular smooth muscle cells accumulated similar or lower amounts of cGMP than human cells, whereas porcine, rat, and rabbit smooth muscle cells accumulated greater amounts of cGMP. In freshly harvested human vessels, cGMP accumulation in response to SNP was found to increase fifteen-fold over baseline. In contrast to the SNP-induced cGMP accumulation, cGMP levels in response to particulate guanylate cyclase activator atriopeptin II were equal to or greater in cultured human cells than in fresh human vascular tissue. We conclude that human vascular cells (fresh and cultured) express the mRNA for both a large (alpha 3) and a small (beta 3) sGC subunit and that fresh human cells are more sensitive to SNP stimulation.