EFFECT OF ACUTE INFLAMMATION ON ENDOTEHIAL FUNCTION, BLOOD PRESSURE. WASTED LEFT VENTRICUALR PRESSURE AND MYOCARDIAL MICROCIRCULATION IN OLDER HYPERTENSIVES

Objective: Acute inflammation increases the risk of mortality and morbidity and decreases endothelial function in older individuals, but the effect on myocardial microcirculation, subendocardial perfusion (SEVR) and wasted left ventricular pressure (Ew) is unknown in hypertensives. We investigated the effect of acute induced inflammation comparing older hypertensives and normotensives. Design and method: We recruited 54 older individuals (22 hypertensives: BP >130/80 using AHA definition; age=67 years; 32 normotensives age=67 years). Baseline data were obtained using standard shpygmomanometry, arterial tonometry (SphygmoCor) for central blood pressure, SEVR and Ew. Flow mediated dilation (FMD) of the brachial artery and carotid artery stiffness were measured using ultrasound (Aloka-Hitachi). Subjects then received an influenza vaccine to induce inflammation, with measurements at 24 and 48 hours after vaccination. Venous blood was collected at each time point and analyzed for CRP and IL-6. Results: At baseline, hypertensives had significantly higher (p<0.05) brachial BP (140/75 vs 116/68 mmHg), aortic SBP (132 vs 109 mmHg), carotid artery stiffness (Elastic modulus (EP) 133 vs 182 kPa), lower FMD (4.4 vs 6.7%) but there was no difference between groups for SEVR, Ew, CRP or IL-6 (p>.05). After vaccination, FMD decreased from baseline to 24 and 48 hrs (p < .05) similarly in hypertensives (4.4 to 4.1 to 2.9%) and normotensives (6.7 to 5.1 to 4.6%) (interaction p>.05), while brachial (140 to 135 to 134 mmHg) and aortic SBP (132 to 125 to 124 mmHg) decreased only in hypertensives (p<.05 for interaction). CRP and IL-6 increased (p<.05) similarly in both groups, while EP, SEVR and Ew did not change in either group. Conclusions: The older hypertensives in this study exhibited the expected increases in both brachial and aortic BP, coupled with increased carotid stiffness, and lower FMD. While FMD decreased in both groups following vaccination, brachial and aortic SBP decreased only in hypertensive, without changes in SEVR, Ew or EP in either group. Whether the very low FMD coupled with the decrease in SBP in response to inflammation constitutes higher risk for hypertensives remains to be determined.