G. Gaudio

Twenty-Four–Hour Noninvasive Blood Pressure Monitoring and Pain Perception

Although a hypertension-related hypalgesia has been described, the relation between pain perception and the 24-hour blood pressure trend is still unknown. The ambulatory blood pressure monitoring parameters and dental pain sensitivity were correlated in 67 male subjects. The pulpar test (graded increase of test current of 0 to 0.03 mA) was performed on three healthy teeth, and mean dental pain threshold (occurrence of pulp sensation) and pain tolerance (time when the subjects asked for the test to be stopped) were evaluated. Three groups of subjects with normal (n = 34), intermediate (n = 13), and high (n = 20) blood pressure values were identified according to ambulatory monitoring results. Pain threshold differed among the three groups (P < .02), being higher in the group with highest blood pressure. The groups of hypertensive subjects showed higher pain tolerance than the normotensive group (P < .02). Pain threshold was correlated with 24-hour, diurnal, and nocturnal blood pressure values. Pain tolerance was also related to 24-hour blood pressure and to diurnal and nocturnal diastolic and mean arterial pressure values. Systolic and diastolic blood pressure loads were significantly associated with pain threshold, and diastolic load was also associated with tolerance. The blood pressure variability (SD) did not relate to pain perception. The 24-hour arterial pressure was more closely associated with pain perception than the blood pressure values obtained before the pulpar test. A close correlation between pain perception and 24-hour ambulatory blood pressure was demonstrated.(ABSTRACT TRUNCATED AT 250 WORDS)

Treatment with enalapril modifies the pain perception pattern in hypertensive patients.

The cardiovascular system shares numerous anatomic and functional pathways with the antinociceptive network. The aim of this study was to investigate whether angiotensin-converting enzyme (ACE) inhibitor treatment could affect hypertension-related hypalgesia. Twenty-five untreated hypertensive patients, together with a control group of 14 normotensive subjects, underwent dental pain perception evaluation by means of a pulpar test (graded increase of test current applied to healthy teeth). After the evaluation of the dental pain threshold (occurrence of pulp sensation) and tolerance (time when the subjects asked for the test to be stopped), all the subjects underwent a 24-hour ambulatory blood pressure monitoring. The hypertensive group then was treated with 20 mg/d enalapril, whereas the normotensive subjects remained without any treatment. After a time interval of 6+/-2 months, the dental pain sensitivity was retested in all the subjects, and ambulatory blood pressure was recorded during treatment in the hypertensive patients. At the first assessment, hypertensive patients showed a higher pain threshold than normotensive subjects (P<.001). On retesting of pain sensitivity in hypertensive patients, a significant decrease of both pain threshold and tolerance, leading to their normalization, was observed during treatment (P<.001 and P<.005, respectively), in the presence of reduced 24-hour and office blood pressure values. A slight, though significant, correlation was observed between variations in pain tolerance and baseline blood pressure changes occurring during treatment. During follow-up, the normotensive subjects did not show any significant pain perception or office blood pressure changes. Hypertension-related hypalgesia was confirmed. Mechanisms acting both through lowering of blood pressure and specific pharmacodynamic properties may account for the normalization of pain sensitivity observed in hypertensive patients during treatment with ACE inhibitors.

Endogenous beta-endorphins in hypertension: Correlation with 24-hour ambulatory blood pressure

OBJECTIVES The aims of this study were to determine whether hypertensive patients showed increased endogenous opioid tone and to find a possible correlation between beta-endorphin levels and 24-h ambulatory blood pressure. We also investigated whether circulating beta-endorphin levels were associated with pain perception at rest. BACKGROUND Experimental studies suggest an involvement of the endogenous opioid system in cardiovascular control mechanisms. METHODS We determined baseline beta-endorphin plasma levels by radioimmunoassay in 81 consecutive subjects (48 hypertensive, 33 normotensive) after a 30-min rest and before 24-h ambulatory blood pressure monitoring. In 72 of 81 subjects with a dental formula suitable for the pulpar test (graded increase of test current -0 to 0.03 mA applied to three healthy teeth), pain perception was also investigated. RESULTS Hypertensive patients showed higher beta-endorphin plasma levels than normotensive subjects (p < 0.002). Circulating endogenous opioid levels correlated with 24-h diastolic blood pressure (p < 0.01), whereas the relation with systolic pressure did not reach statistical significance. When 24-h blood pressure recordings were divided into daytime and nighttime values, and blood pressure loads (percent of measurements > or = 140 mm Hg for systolic blood pressure and > or = 90 mm Hg for diastolic pressure) were calculated, a significant correlation was found between beta-endorphin levels and diastolic pressures and load. Similarly, presampling diastolic blood pressure was significantly correlated with beta-endorphin levels. Of the 72 subjects tested, hypertensive patients showed a lower pain sensitivity than normotensive subjects. A positive correlation was found between pain threshold and circulating beta-endorphin levels (p < 0.05). CONCLUSIONS Sustained arterial pressure is probably involved in the tonic activation of cardiovascular mechanisms linked to endogenous opioid tone. Circulating plasma endorphins may account, at least in part, for the pain perception pattern relating to blood pressure levels at rest.

Hyperinsulinemia, family history of hypertension, and essential hypertension

The aim of this study was the evaluation of the relationships among hyperinsulinemia, a family history of hypertension, and essential hypertension. Insulin and C-peptide responses to an oral glucose load were studied in 175 lean normotensives (N) and untreated hypertensives (H) with (F+) and without (F-) a family history of hypertension: 30 NF-, 30 NF+, 45 HF-, and 70 HF+. The groups were comparable for age, sex, body mass index, and blood pressure. The following parameters were evaluated: plasma glucose (G), serum insulin (I), and C-peptide (Cp) before and 30, 60, 90, and 120 min after the glucose load, fasting glucose/insulin ratio (ISI), fasting insulin/C-peptide ratio (I/Cp), and 24-h ambulatory blood pressure monitoring. Plasma glucose was measured, fasting and during the test, and it and I/Cp were similar in the four groups. Serum insulin and Cp, both fasting and stimulated, were significantly higher and ISI lower in normotensives and hypertensives with hypertensive parents. Grouping the subjects first on the basis of blood pressure and then on the basis of family history, no differences were found between normotensives and hypertensives, whereas I and Cp, fasting and stimulated, were significantly higher and ISI lower in subjects with positive as compared to negative family history. The closest correlations between insulin and ambulatory blood pressure were found in normotensive with hypertensive parents; in hypertensives with hypertensive parents we only found a direct correlation between fasting Cp and nocturnal blood pressure fall; in hypertensives with normotensive parents insulin inversely correlated with nocturnal blood pressure fall. Insulin resistance seems to have a familial basis, independently of the presence of hypertension. Instead of showing a causal relationship between insulin resistance and hypertension, our results indicate that the two are partly independent components of a common familial pattern.

Influence of family history of hypertension on insulin sensitivity in lean and obese hypertensive subjects

We evaluated the influence of family history of hypertension on insulin sensitivity in lean and obese hypertensive subjects (H): 40 lean [body mass index (BMI)  25 kg m−2] H with normotensive parents (F−), 50 lean H with one or two parents hypertensive (F+), 30 obese HF− (BMI  30 kg m−2) and 35 obese HF+. The four groups were comparable in terms of age, sex and ambulatory blood pressure values. We evaluated glucose, insulin and C‐peptide before and 30, 60, 90 and 120 min after an oral glucose load, insulin sensitivity index (ISI, fasting glucose/insulin ratio), fasting insulin/C‐peptide ratio (I/Cp). Glucose, fasting and during test, and I/Cp were similar among the four groups; insulin and C‐peptide, fasting and stimulated, were significantly higher and ISI lower in obese H than in lean H; at similar BMI, insulin and C‐peptide were significantly higher in F+ than in F−. Insulin directly correlated with night‐time blood pressure only in lean HF−. The correlation between insulin and BMI was significantly closer in F− than in F+. In conclusion, family history of hypertension appears to play a relevant role in insulin sensitivity in hypertensive subjects also in the presence of obesity.

Effects of sustained-release isradipine on left ventricular anatomy and function in systemic hypertension

With use of digitized M-mode echocardiograms and 24-hour noninvasive ambulatory blood pressure (BP) monitoring, the effects of chronic treatment with sustained-release isradipine on left ventricular (LV) morphology and function in hypertensive patients were evaluated. We selected 12 patients with LV hypertrophy and normal LV diastolic diameter. Echocardiograms and 24-hour BP monitoring were performed after 2 weeks of placebo and after 6 months of oral treatment with sustained-release isradipine (5 mg once daily). Therapy significantly reduced BP without changes in heart rate. LV mass decreased in all patients and peak lengthening rate of LV diameter, index of diastolic function, increased in all, with normalization in 7 of the 9 with basal diastolic impairment. Peak shortening rate of LV diameter, index of systolic function, was normal in all patients at basal evaluation and did not change after therapy. Reduction in LV mass significantly (p < 0.05) correlated with the decrease in average 24-hour and daytime systolic and diastolic BP. Sustained-release isradipine administered once daily is an effective antihypertensive agent; the drug also induces regression of LV hypertrophy, with significant improvement in LV diastolic function and no deterioration in systolic function.

Clinical Feasibility of Echocardiographic Automated Border Detection in Monitoring Left Ventricular Response to Acute Changes of Preload in Normal Subjects

Echocardiographic automated border detection (ABD) provides an instantaneous measurement of left ventricular (LV) volume and its rate of change. We tested the clinical feasibility of ABD in monitoring on-line LV response to acute changes in preload. We examined 20 healthy males in the supine position, with legs elevated, back in the supine position, 5 min after the inflation of blood pressure cuffs at the root of the four limbs, 5 min after the deflation of cuffs. End-diastolic and end-systolic LV volumes significantly increased with elevated legs and decreased during cuff inflation; ejection fraction remained unchanged. Peak filling and peak emptying rates did not change with elevated legs and increased significantly during cuff inflation. The values of LV parameters were stable in the three resting conditions, demonstrating a good reproducibility of the ABD technique. Our results demonstrate that ABD may be useful in clinical practice for monitoring on-line small acute changes in LV volume and function.