The study of hypertension in China.

It is an honor for me to be invited to contribute to this “personal review” of Blood Pressure. A prestigious journal focused on hypertension (HT) management and research, Blood Pressure is nowadays more relevant than ever, as an abundance of evidence has been accumulated which proves that blood pressure (BP) is linearly related to cardiovascular diseases (CVD) complications without a cut-off point between normal and abnormal. The study of HT in China started in early 1950s, a few years after the founding of the People’s Republic in 1949. However, during the next 30 years or so, from the 1950s to the 1970s, when China was isolated from international exchange or collaboration in medical sciences, Chinese studies were unknown to the outside world, and most papers were published only in Chinese and were even unsigned. As one of those who took part in the study of HT from the very beginning and witnessed its development and progress in those difficult years, I take it as an obligation to write a review on the range of scientific activities, both successful and unsuccessful, which were devoted to the study of HT in China in the 1950s to 1970s. Back in early 1950s, even when some infectious diseases were still prevalent, a group of cardiologists and epidemiologists had foreseen the threat of the growing HT on public health. In the Chinese Journal of Medicine, there started a heated discussion about HT criteria, differential diagnosis and clinical management, but the discussion centered mostly on severe and malignant cases, on “rice diet therapy”, etc. Since at that time only reserpine and diuretics were available, sedatives were used quite often followed by hydralasine, ganglion blockers or sympathectomy. All the patients in our HT ward of Fu Wai Hospital at that time were severe or malignant cases. In the period 1950–60, Huang & Liu [1] observed a group of malignant HT cases, mostly young females who were diagnosed as pulseless disease, or claudication, or atypical congenital coarctation of the aorta, but were actually suffering from partial or complete obstruction of the aorta and its main branches including renal arteries. The divergent clinical pictures were merely manifestations of a common pathological process, namely constrictive arteritis. This kind of arteritis is quite common in oriental populations, especially in young women. In the 1958–59, 13 provinces conducted BP surveys on a total of 740000 people. The average prevalence rate of HT was found to be 5.11%. One year later, in 1959, the 1st National Symposium on CVD was held in Xian. At this symposium, the HT diagnostic criterion for Chinese, based on a Chinese Academy of Medical Sciences (CAMS) BP survey, was proposed by Huang & Gao. The intersecting points – 140 systolic and 90 diastolic of two distribution curves, one for the population with target organ damage signs, the other for those without any target organ damage – were set as cut-off points. Though conservative, this criterion was still found to be more or less fit for Chinese people. An HT prevention and management collaborative group involving specialists of psychology, physiology, pharmacology, epidemiology, statistics and cardiology was subsequently organized by CAMS. This collaboration between basic sciences and clinical sciences was later found to be highly productive. At that time, psychological and central nervous system effects were given much attention. Chinese scientists believed that cerebral cortical activation had some impact on the pathogenesis of HT. In the 1950s, our pharmacologists used to employ renovascular HT (RVH) dog models for experiments, but in the 1960s, HT in dogs was developed by intensified tension of higher nervous activities by Jin & Zeng [2–4]. The co-authors named this model “neuropsychogenic HT”, which was found to be closer to essential HT in human beings. Plasma Ca determined by bioassay showed that the plasma Ca increased with daily stimulation. It was speculated that a disorder of the vasomotor center was involved in this experimental model development. The effects of reserpine [5] on BP, heart rate, higher nervous activity and plasma CA level during the development of neuropyschogenic HT induced by overstrain of central nervous system were also tested in this model. The result showed that reserpine had inhibitory influence on the development of HT in this model but could not prevent the development of HT completely.