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Featured researches published by Iwao Kuwajima.


American Heart Journal | 1992

Diminished nocturnal decline in blood pressure in elderly hypertensive patients with left ventricular hypertrophy

Iwao Kuwajima; Yasuko Suzuki; Tatsuo Shimosawa; Akiko Kanemaru; Satoshi Hoshino; Kizuku Kuramoto

To assess the circadian blood pressure (BP) changes in elderly hypertensive patients with left ventricular hypertrophy (LVH), the ambulatory BP was measured noninvasively every 30 minutes for 24 hours in those patients with LVH (n = 15) and without LVH (n = 23), and in normotensive elderly subjects (n = 11). Although the daytime systolic BP (SBP) was comparable in the two hypertensive groups, the nighttime SBP in patients with LVH tended to be higher than in patients without LVH (149.0 +/- 15.1 versus 138.4 +/- 20.1 mm Hg, p less than 0.10). The LV mass index correlated significantly with the nighttime SBP (r = 0.43, p less than 0.01), but not with the daytime SBP (r = 0.24, ns), with clinic SBP (r = 0.14, p = ns) or the SBP after handgrip exercise (r = 0.31, p = ns). The difference in the systolic BP between daytime and nighttime (D-N SBP) in patients with LVH (2.8 +/- 9.4 mm Hg) was significantly less than that in patients without LVH (12.8 +/- 16.0 mm Hg) (p less than 0.02). In addition, the D-N SBP correlated inversely with the left ventricular mass index (r = -0.33, p less than 0.05). It was concluded that hypertension in the elderly with LVH was associated with a diminished nocturnal decline in blood pressure.


American Journal of Hypertension | 1995

Cardiac implications of the morning surge in blood pressure in elderly hypertensive patients: Relation to arising time

Iwao Kuwajima; Kenichi Mitani; Mariko Miyao; Yasuko Suzuki; Kizuku Kuramoto; Toshio Ozawa

Although morning surge in blood pressure has been shown to be associated with the occurrence of myocardial ischemic events and stroke, few studies have been done regarding its pathogenesis, probably because of a lack of method for the quantitative assessment of awakening time. We conducted an echocardiographic study and ambulatory blood pressure monitoring in 23 elderly hypertensive patients to evaluate the relationship between the hypertensive cardiac change and morning surge in blood pressure. Of note was that the time of arising from bed was assessed quantitatively by an activetracer equipped with an internal acceleration sensor to monitor the physical activity. The change in systolic blood pressure after arising from bed was correlated significantly with the left ventricular mass index (r = 0.51, P < .02) and the A/E ratio, which represents the diastolic function (r = 0.70, P < .01). In contrast, the change in systolic blood pressure before rising from bed was not correlated with any echocardiographic parameters. We conclude that the magnitude of morning surge in blood pressure after arising from bed was related with the severity of hypertensive target organ damage.


Cardiovascular Research | 2001

Measurement of plasma brain natriuretic peptide level as a guide for cardiac overload.

Yasunobu Hirata; Akihiro Matsumoto; Teruhiko Aoyagi; Kazuhide Yamaoki; Issei Komuro; Toru Suzuki; Terunao Ashida; Takuro Sugiyama; Yoshiyuki Hada; Iwao Kuwajima; Masanori Nishinaga; Hisashi Akioka; Osamu Nakajima; Ryozo Nagai; Yoshio Yazaki

OBJECTIVES We examined whether measurement of the plasma BNP concentrations might be useful for the early diagnosis of the existence and severity of disease in patients with heart disease in daily clinical practice. METHODS AND RESULTS The plasma BNP and ANP concentrations in 415 patients with heart disease and hypertension and 65 control subjects were measured. Patients with heart disease had higher plasma BNP and ANP concentrations than did those with hypertension or control subjects. Among the etiology of cardiac diseases, specifically dilated cardiomyopathy and hypertrophic cardiomyopathy, was associated with the highest plasma BNP concentrations, whereas dilated cardiomyopathy was associated with the highest plasma ANP concentrations. Plasma BNP concentrations showed an increase as the severity of the heart disease, as graded according to the NYHA classification of cardiac function, increased. In both patients with heart disease and hypertension, the plasma BNP values were higher in those who had abnormalities in their echocardiogram and electrocardiogram as compared to those without any abnormalities. The plasma BNP levels also showed a significant correlation with left ventricular wall thickness and left ventricular mass. On the other hand, the plasma ANP levels showed significant correlations with left ventricular dimension. Receiver operative characteristic analysis revealed that plasma BNP levels showed substantially high sensitivity and specificity to detect the existence of heart diseases. CONCLUSION Measurements of the plasma BNP concentrations is useful to detect the existence of the diseases, and abnormalities of left ventricular function and hypertrophy in patients with heart disease in daily clinical practice.


Hypertension Research | 2012

The Japanese Society of Hypertension Guidelines for Self-monitoring of Blood Pressure at Home (Second Edition)

Yutaka Imai; Kazuomi Kario; Kazuyuki Shimada; Yuhei Kawano; Naoyuki Hasebe; Hideo Matsuura; Takuya Tsuchihashi; Takayoshi Ohkubo; Iwao Kuwajima; Masaaki Miyakawa

The Japanese Society of Hypertension Guidelines for Self-monitoring of Blood Pressure at Home (Second Edition)


Journal of Hypertension | 1992

The cardiac functional reserve in elderly hypertensive patients with abnormal diurnal change in blood pressure

Yasuko Suzuki; Iwao Kuwajima; Akiko Kanemaru; Tatsuo Shimosawa; Satoshi Hoshino; Makoto Sakai; Satoru Matsushita; Keiji Ueda; Kizuku Kuramoto

Objective: To evaluate the left ventricular function of hypertensive patients with abnormal diurnal change in blood pressure. Design: We compared left ventricular structural and functional characteristics between hypertensive patients with a normal diurnal change in blood pressure (H2 group) and those with a nocturnal blood pressure increment (H1 group) using echocardiography. Methods: The study group consisted of 36 hypertensives and 16 normotensives whose 24-h ambulatory blood pressure monitorings were measured non-invasively. The hypertensive group was subdivided into the H1 group, consisting of 11 patients (76 ± 7 years), and the H2 group with 25 patients (73 ±7 years). The normotensive control group had a mean age of 73 ± 6 years. Echocardiographic examinations were performed before and at the end of isometric exercise (handgrip for 3 min) and isoproterenol infusion (0.02 ug/kg per min for 5 min). Results: The left ventricular mass index in the H1 group was significantly greater than in the H2 or control group. Left ventricular fractional shortening (LVFS) at rest in the H1 group was also significantly greater than in the other two groups. However, the peak late: early diastolic filling ratio, which indicated diastolic function, significantly deteriorated in the H1 group compared with the H2 and control groups. Furthermore, changes in LVFS after isometric exercise in the H1 group were more supressed than in the H2 or control group. In addition, a significantly lower increment in LVFS after isoproterenol was observed in the H1 group compared with the H2 or control group. Conclusion: The H1 group had greater left ventricular mass and impaired left ventricular functional reserve than the H2 group.


Hypertension Research | 2005

The Japanese trial to assess optimal systolic blood pressure in elderly hypertensive patients (JATOS): Protocol, patient characteristics, and blood pressure during the first 12 months

Yoshio Goto; Masao Ishii; Takao Saruta; Tadashi Kawakami; Kanemi Kawabe; Toshio Ogihara; Yuhei Kawano; Kenjiro Kikuchi; Kazuaki Shimamoto; Masayuki Sakurai; Makoto Sugahara; Sadayoshi Ito; Hiroaki Matsuoka; Yoshihiko Sato; Seishiro Ono; Satoshi Umemura; Yoshiro Shiota; Masaaki Miyagawa; Kenichi Doniwa; Genjiro Kimura; Yutaka Tada; Masayoshi Nakao; Takeshi Takami; Mikio Arita; Mitunori Okamoto; Kunio Hiwada; Masunori Matsuzaki; Akira Takeshita; Kozaburo Abe; Takashi Honda

The benefits of a systolic blood pressure (BP) below 150–160 mmHg are well established; whether a systolic BP of less than 140 mmHg provides additional benefits remains controversial. This study was designed to compare the 2-year effect of a strict treatment to maintain systolic BP below 140 mmHg (group A) and that of a mild treatment to maintain systolic BP at between 140 and below 160 mmHg (group B). The study design followed the Prospective Randomized Open Blinded End-point (PROBE) study. The subjects were elderly patients (65–85 years old) who consistently had a systolic BP of 160 mmHg or higher. The baseline drug was efonidipine hydrochloride (efonidipine), a long-acting dihydropiridine calcium antagonist. The primary endpoints were stroke, cardiac disease, vascular disease, and renal failure. After a run-in period of 2 to 4 weeks, 2,165 patients were assigned to group A and 2,155 patients to group B. There were no significant differences between the groups in sex, age, baseline BP, or other cardiovascular risk factors. The systolic BP was 7.2 mmHg lower (p<0.0001) and the diastolic BP 2.4 mmHg lower (p<0.0001) in group A than in group B after 12 months of treatment. As of this interim analysis, primary endpoints have occurred in 87 patients (stroke in 58 patients, cardiac disease in 27 patients, occlusive arterial disease in 1 patient, and renal failure in 1 patient). Five patients have died of stroke and 2 patients of myocardial infarction. The primary-endpoint-related morbidity rate was 20.9/1,000 patient-years, and the mortality rate was 1.7/1,000 patient-years. Currently available results indicate that this study, one of the largest randomized trials of antihypertensive therapy in elderly patients in Japan, was conducted safely. The final results are expected to provide important and practical information for the management of hypertension in elderly patients.The benefits of a systolic blood pressure (BP) below 150–160 mmHg are well established; whether a systolic BP of less than 140 mmHg provides additional benefits remains controversial. This study was designed to compare the 2-year effect of a strict treatment to maintain systolic BP below 140 mmHg (group A) and that of a mild treatment to maintain systolic BP at between 140 and below 160 mmHg (group B). The study design followed the Prospective Randomized Open Blinded End-point (PROBE) study. The subjects were elderly patients (65–85 years old) who consistently had a systolic BP of 160 mmHg or higher. The baseline drug was efonidipine hydrochloride (efonidipine), a long-acting dihydropiridine calcium antagonist. The primary endpoints were stroke, cardiac disease, vascular disease, and renal failure. After a run-in period of 2 to 4 weeks, 2,165 patients were assigned to group A and 2,155 patients to group B. There were no significant differences between the groups in sex, age, baseline BP, or other cardiovascular risk factors. The systolic BP was 7.2 mmHg lower (p<0.0001) and the diastolic BP 2.4 mmHg lower (p<0.0001) in group A than in group B after 12 months of treatment. As of this interim analysis, primary endpoints have occurred in 87 patients (stroke in 58 patients, cardiac disease in 27 patients, occlusive arterial disease in 1 patient, and renal failure in 1 patient). Five patients have died of stroke and 2 patients of myocardial infarction. The primary-endpoint-related morbidity rate was 20.9/1,000 patient-years, and the mortality rate was 1.7/1,000 patient-years. Currently available results indicate that this study, one of the largest randomized trials of antihypertensive therapy in elderly patients in Japan, was conducted safely. The final results are expected to provide important and practical information for the management of hypertension in elderly patients.


Blood Pressure Monitoring | 2002

Blood pressure measurement in research.

Gianfranco Parati; Peter W. de Leeuw; Miklos Illyes; Stevo Julius; Iwao Kuwajima; Jean-Michel Mallion; Kuniaki Ohtsuka; Yutaka Imai

ObjectiveThe aim of this paper is to summarize the issues raised during a consensus conference on the role of different blood pressure (BP) monitoring techniques in research, including pathophysiological studies, clinical outcome trials and clinical pharmacology trials. MethodsThis review includes the contribution of the participants in a task force at the Eighth Consensus Conference on Ambulatory BP Monitoring (October 28–31, 2001, Sendai, Japan) and the results of a discussion open to all conference participants. Individual contributions have been summarized together with the points raised during the subsequent discussion, and the main statements are also presented in a table format. Points of consensus(1) BP monitoring in pathophysio-logical studies. The essential role played by continuous BP monitoring in this field had been acknowledged, and further development of non-invasive beat-by-beat monitoring techniques has been advocated.(2) BP monitoring in clinical trials. In clinical trials automated ambulatory BP monitoring (ABPM) and self BP measurements (SBPM) at home share similar advantages, with specific features that make these approaches not alternative solutions but rather approaches able to complement each other. A few examples of application of ABPM and SBPM in clinical trials include the Treatment of Hypertension according to Home or Office Blood Pressure (THOP) trial and the Trial of Preventing Hypertension (TROPHY).(3) Use of ABPM in clinical pharmacology studies. Use of ABPM is now an established routine, aimed at describing the 24-h effect of new antihypertensive drugs. An example of these applications that was discussed in the conference is the use of ABPM in the evaluation of a new long-acting calcium channel blocker (Barnidipine) (J-MUBA study).(4) Specific models for the analysis of BP fluctuations. The features characterizing the chronobiological approach to description of 24-h BP profiles and its limitations (mainly consisting of the high risk of data over-modelling) are discussed. Also the possible occurrence of a circaseptan (approximately with a 7-day period) rhythm in BP has been addressed, although repeated performance of 24-h ABPM over a week obviously faces a number of practical problems.(5) Progress in technology:BP monitoring and telemedicine. The possibility to implement an interactive telemonitoring system of home SBPM values and the perspectives for a clinical application of this technology in the Hypertension Objective treatment based on Measurement by Electrical Devices of Blood Pressure (HOMED-BP) trial is discussed.


Journal of Hypertension | 1990

Pseudohypertension in the elderly

Iwao Kuwajima; Eitetsu Hoh; Yasuko Suzuki; Satoru Matsushita; Kizuku Kuramoto

Pseudohypertension is a condition in which indirect blood pressure measured by the cuff method overestimates the true intra-arterial blood pressure. Despite the clinical importance of pseudohypertension, reports regarding its prevalence are scarce. We compared direct measurements of brachial arterial blood pressure with those measured indirectly by the cuff method in 59 healthy volunteers aged greater than 65 years, with or without hypertension, in order to investigate the prevalence of pseudohypertension in the elderly. The average systolic blood pressure of 161.5 mmHg obtained by the indirect method was significantly lower than the 169.2 mmHg obtained by the direct method was not significantly different from the 76.9 mmHg obtained by the direct method. Only one volunteer was observed in whom the indirect cuff method overestimated the diastolic blood pressure by greater than 10 mmHg, which was defined as pseudohypertension. Thus, the prevalence of pseudohypertension was only 1.7%. The difference in systolic blood pressure between the two methods was 8.7 mmHg in Osler-positive cases and was not significantly different from the 6.9 mmHg observed in Osler-negative cases. Pulse wave velocity was significantly correlated with the systolic blood pressure (y = 11.4x + 66.1, r = 0.65, P less than 0.05). No correlation was observed between the pulse wave velocity and direct/indirect pressure differences for either systolic or diastolic measurements. These results show that the prevalence of pseudohypertension is very low in a non-selected elderly population and that Oslers maneuver was not related to the pressure difference between the direct and indirect methods.


Hypertension Research | 2006

Workplace hypertension is associated with obesity and family history of hypertension.

Kazumasa Harada; Yuya Karube; Hirokazu Saruhara; Kazuhiro Takeda; Iwao Kuwajima

Job strain, which is a risk for hypertension and increased left ventricular mass, is thought to cause masked hypertension during work even if blood pressure (BP) is normal at health examinations. To study the prevalence of and factors related to workplace hypertension, 265 public officials (mean age, 41.4±10.7 years) measured their own BP at their workplace using semiautomated BP measurement devices. Factors related to workplace hypertension were assessed with multiple regression analysis. Workplace hypertension, defined as a BP no less than 140/90 mmHg, was observed in 23% of subjects (n=61). Compared with subjects without workplace hypertension (n=204), subjects with workplace hypertension were older (48.5±10.0 vs. 39.3±10.0 years), more likely to be men (69% vs. 46%), and had a higher body mass index (BMI) (23.4±2.7 vs. 21.6±3.2 kg/m2), higher cholesterol levels (214±33 vs. 194±36 mg/dl), and a higher Brinkman index (134±228 vs. 59±148). Subjects with workplace hypertension had higher BPs at checkup than did those without it (125±11/79±9 vs. 110±11/68±9 mmHg). The increases in BPs at the workplace were independently and significantly correlated with BMI, and a family history of hypertension. BP no less than 130/85 mmHg at health checkup was a good detector of workplace hypertension (sensitivity, 49%; specificity, 91%), suggesting that subjects with high-normal BPs at health checkup might have workplace hypertension. In conclusion, workplace hypertension was found to be associated with age, BMI, a family history of hypertension, and high-normal BPs at health checkup.


American Journal of Cardiology | 1994

Diagnostic value of electrocardiography and echocardiography for white coat hypertension in the elderly

Iwao Kuwajima; Mariko Miyao; Ayako Uno; Yasuko Suzuki; Satoru Matsushita; Kizuku Kuramoto

Abstract Although white coat hypertension is common in clinical practice, 1–3 its pathogenesis and clinical prognosis remain unknown. In elderly patients with office hypertension, white coat hypertension should be differentiated from true hypertension, since the excessive reduction in blood pressure (BP) caused by antihypertensive medication may induce an ischemic event in a vital organ. The present study assesses the sensitivity and specificity of electrocardiography in detection of white coat hypertension and quantitatively measures left ventricular hypertrophy in such patients using echocardiography. Results are compared with those in normotensive control subjects and in patients with true persistent hypertension.

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