Epidemiological study of hypertension in natives of Spiti Valley in Himalayas and impact of hypobaric hypoxemia; a cross-sectional study.

Hypertension is the result of interaction between genetic vulnerability and exposure to unhealthy lifestyle. However, studies investigating the impact of cardiovascular adaptive response to hypobaric hypoxia and extreme cold in natives of high altitude on the development of hypertension have yielded conflicting results. A community based cross-sectional study was carried out in an unique population of Spiti valley of Greater Himalayas residing at an altitude of 3100-3500 m (group 1) and 3500 m and above (group 2) to evaluate the impact of altitude of residence on prevalence of hypertension. 413 subjects, age 20 years and above were selected by stratified cluster random sampling technique and screened for recording socio-demographic profile, anthropometrics, fasting blood sugar and blood pressure. There was no significant difference in the mean age (40.1 vs.38.0 years) and gender distribution (65.7% vs. 61.4% females) between the two groups. The overall prevalence of hypertension was 22.5% and achieved higher significance in group 1 (27.5%) compared to group 2 (19%); p < 0.041. The socioeconomic profile and lifestyle of group from higher altitude was significantly different with people being less educated, agriculture as main occupation compared to the group at lower altitude. On comparison, the same group had a lower prevalence of obesity 17.4% vs. 35.9% (p < 0.000), Diabetes 0.4% vs. 4.1% (p < 0.03) and impaired fasting glucose 5% vs. 11.1% (p < 0.06). Obesity, age and altitude of residence were significantly associated as independent predictors of prevalence of hypertension in this study. Hypobaric hypoxia thus appears to have a protective effect from developing hypertension. The prevalence of hypertension in natives of Spiti valley is thus influenced by lifestyle related risk factors, age and possibly altitude of residence.

Oral tadalafil in pulmonary artery hypertension: a prospective study.

BACKGROUND: Pulmonary artery hypertension is a disorder with limited treatment options and poor prognosis. We studied the effect of tadalafil, a selective phosphodiesterase type 5 inhibitor, in patients with this disease. METHODS AND RESULTS: In thirteen patients (5 males, 8 females) aged 15-70 years, with pulmonary artery hypertension (7 with congenital heart disease, 4 with chronic pulmonary thromboembolism and 2 with primary pulmonary hypertension), tadalafil was added to their baseline therapy at 10 mg OD for two weeks and if tolerated well, increased to 20 mg OD for the next two weeks. After four weeks of therapy, all thirteen patients had subjective improvement in the form of overall well being and objective improvement as measured by duration of exercise on treadmill following Bruce protocol from a baseline of 350.54+/-255.06 seconds to 479.54+/-195.00 seconds (p<0.01). There was improvement in NYHA functional class in eleven patients. Two patients, though showed no improvement in functional class, had subjective improvement in effort tolerance and objective improvement as measured by duration of exercise on TMT. Hemodynamic parameters showed a trend towards improvement, mean pulmonary artery mean pressure decreased from 63.5+/-26.2 mmHg to 62.2+/-24.8 mmHg (p>0.05), mean pulmonary blood flow increased from 3.26+/-1.04 L/min to 3.44+/-1.26 L/min (p>0.05), mean total pulmonary vascular resistance decreased from 1858.6+/-1138.9 dyne-sec.cm-5 to 1737.3+/-1017.2 dyne-sec.cm-5 (p>0.05). CONCLUSION: Oral tadalafil was well tolerated and had a beneficial effect in patients with pulmonary artery hypertension irrespective of age, sex and underlying etiology. Patient had improved effort tolerance and a trend towards improved pulmonary hemodynamics.

Prevalence of high altitude pulmonary hypertension among the natives of Spiti Valley--a high altitude region in Himachal Pradesh, India.

The study aimed to determine the prevalence of high altitude pulmonary hypertension (HAPH) and its predisposing factors among natives of Spiti Valley. A cross-sectional survey study was done on the permanent natives of Spiti Valley residing at an altitude of 3000 m to 4200 m. Demographic characteristics, health behavior, anthropometrics, and blood pressure were recorded. Investigations included recording of 12 lead electrocardiogram (ECG), SaO2 with pulse oximeter, spirometry and echocardiography study, and measurement of Hb levels using the cynmethhemoglobin method. HAPH was diagnosed using criteria; tricuspid regurgitation (TR) gradient of ≥46 mmHg. ECG evidence of RV overload on 12 lead ECG was documented based on presence of 2 out of 3 criteria; R>S in V1, right axis deviation or RV strain, T wave inversion in V1 and V2. Data of 1087 subjects were analyzed who were free of cardiorespiratory diseases to determine the prevalence of HAPH and its predisposing factors. HAPH was recorded in 3.23% (95% C.I. of 0.9-8.1%) and ECG evidence of right ventricular (RV) overload was 1.5% in the study population. Prevalence of HAPH was not different in men and women 2.63% vs. 3.54% p<0.2. Age (Z statistics of 3.4 p<0.0006), hypoxemia (Z statistics of 2.9 p<0.002), and erythrocythemia (Z statistics of 4.7 p<0.003) were independently associated with HAPH. Altitude of residence was not found to be significantly associated with HAPH, although there was a trend of increasing prevalence with increasing altitude. It can be concluded that HAPH is prevalent in 3.23% of natives of Spiti Valley. Increasing age, erythrocythemia and hypoxemia are independent predisposing factors.