DESPITE LIMITED BENEFIT, FUNDUSCOPIC EXAMINATION SHOULD BE CONTINUED FOR HYPERTENSION

Sonuçlar: Yetmiş dört NT vakası ve 46 HT hastası çalışmaya alındı. Gruplar arasında ortalama yaş, cinsiyet ve sigara, diyabet, hiperbetalipoproteinemi ve dislipidemi prevelansları açısından istatistiksel olarak anlamlı bir farklılık yoktu. Ancak obezite (%27.0’a karşılık %54.3, p<0.001) ve hipertrigliseridemi (%13.5’e karşılık %28.2, p<0.01) prevelansları HT grubunda anlamlı şekilde yüksekti. Her iki grupta da hiçbir grade III veya IV hipertansif retinopati (HR) vakasına rastlanmadı. Gruplar arasındaki fark grade I HR prevelansı açısından anlamsızdı, ancak grade 0 HR prevelansı HT grubunda anlamlı şekilde düşük iken (%55.4’e karşılık %32.6, p<0.01), grade II HR prevelansı anlamlı şekilde yüksekti (%4.0’a karşılık %13.0, p<0.01).


INTRODUCTION
Hypertension (HT) is one of the most important risk factors of mortality (1), and it affects majority of elders in the world (2)(3)(4). Thus blood pressure (BP) control is the mainstay for prevention of cardiovascular diseases, including myocardial infarction, cardiomyopathy, heart failure, peripheric artery disease, dissecting aortic aneurysm, and stroke. But management of HT is difficult due to fact that BP varies greatly depending on various stresses. Additionally, elder individuals tend to have an abnormal circadian rhythm and a normally higher systolic BP. Beside them, in doctor's office in particular, measurements are often too high, which is called as white coat hypertension (WCH), and prognostic significance of WCH remains unclear (5)(6)(7). Masked HT is another handicap of the office blood pressure (OBP) measurements, in which although the normal OBP values, home blood pressure (HBP) measurements are high, and it may even be together with already existing sequelae of HT (5). So conventional BP measurements may not identify some individuals at high or low risk for HT, and some additional supplementary procedures are required for the diagnosis and management of HT.
Although the whole afferent vasculature of body is probably affected from HT, one of the obvious results can be seen in eyes, and funduscopic examination is regularly performed to evaluate the effectiveness of antihypertensive therapies. Keith, Wagener, and Barker (KWB) classification of hypertensive retinopathy (HR) is used to define funduscopic findings, currently (8). By this way, beside the evaluation of effectiveness of the therapies, we can also catch some overlooked cases of HT. But there are various reports about the benefit of this procedure. We tried to understand significance of funduscopic examination for HT in the study.

MATERIAL AND METHODS
The study was performed on routine check up cases in the Internal Medicine Polyclinic of the Mustafa Kemal University between January and June 2010. We took consecutive patients aged between 35 and 70 years to be able to see the possible consequences of HT on retinal vasculature and to avoid debility induced weight loss in elders. Their medical histories including smoking habit and already used medications were learnt, and a routine check up procedure including fasting plasma glucose (FPG), low density lipoprotein cholesterol (LDL-C), triglyceride (TG), and high density lipoprotein cholesterol (HDL-C) was performed. Current regular smokers at least for 6 months and cases with a previous smoking history of at least five pack-years were accepted as smokers, and cigar and pipe smokers were excluded. Insulin using diabetics and patients with devastating illnesses including malignancies, acute or chronic renal failure, chronic liver diseases, hyper-or hypothyroidism, and heart failure were excluded to avoid their possible effects on weight. Body mass index (BMI) of each case was calculated by the measurements of the same physician instead of verbal expressions. Weight in kilograms is divided by height in meters squared, and obesity is defined as a BMI of 30 kg/m(2) or greater (9). OBP was checked after a 5-minute of rest in the seated position with a mercury sphygmomanometer, and no smoking was permitted during the previous 2-hour. A 14-day twice daily measurements of HBP was obtained in all cases (10), even in normotensives in the office due to the risk of masked HT after a 10minute education about proper BP measurement techniques. A 24-hour ambulatory blood pressure monitoring (ABPM) was not required due to its equal effectiveness with HBP measurements (3). HT was defined as a BP of 135/85 mmHg or greater on mean HBP measurements, and cases were subdivided into the normotension (NT) and HT groups. Cases with an overnight FPG level of greater than 125 mg/dL on two occasions or cases already taking antidiabetic medications were defined as diabetics. An oral glucose tolerance test with 75-gram glucose was performed in cases with a FPG level between 110 and 126 mg/dL, and diagnosis of cases with a 2-hour plasma glucose level of 200 mg/dL or higher is diabetes mellitus (DM).
Additionally, patients with dyslipidemia were detected, and we used the National Cholesterol Education Program Expert Panel's recommendations for defining dyslipidemic subgroups (9). Dyslipidemia is diagnosed when LDL-C is 160 or greater or TG is 200 or greater, or HDL-C is lower than 40 mg/dL. Funduscopic examination was performed via +90D lenses containing biomicroscope by the same ophthalmologist with or without dilatation of pupil according to severity of cases. The ophthalmologist was blind about the patients' subclassifications to prevent observer bias. HR was assessed according to KWB classification, and graded as shown in Table 1. Prevalences of smoking, obesity, DM, hyperbetalipoproteinemia, hypertriglyceridemia, dyslipidemia, and grades of HR were found in each group and compared in between. Mann-Whitney U test, Independent-Samples T test, and comparison of proportions were used as the methods of statistical analyses.

RESULTS
We studied 74 cases with NT and 46 with HT. Characteristic features of the study cases were shown in Table 2. There were nonsignificant differences according to the mean age, gender distribution, and prevalences of smoking, DM, hyperbetalipoproteinemia, and dyslipidemia between the groups, whereas differences were significant according to the prevalences of hypertriglyceridemia (13.5% versus 28.2%, p<0.01) and obesity (27.0% versus 54.3%, p<0.001), and both of which were higher in the HT group. The significant relationships between HT, hypertriglyceridemia, and obesity are probably components of the metabolic syndrome. No case of grade III or IV HRs was detected in any group.  Funduscopic examination according to classification of KWB is used to assess retinal damage in HT since 1939. But again there are various reports about benefits of the procedure. In one side, due to the high prevalences of retinal arteriosclerosis in untreated subjects with mild HT, it could not be considered as a proof of TOD in HT (12). Additionally, association of retinopathy with other predictive parameters of TOD was inconsistent, and its association with cardiovascular complications was weak (13). Parallel to our results, all abnormalities were mild (Grades I and II of KWB), which also caused some diagnostic difficulties to distinguish normal from pathological ones in another study (14). Similarly, severity of HT did not vary parallel to the grades I and II of KWB, and positive and negative predictive values of any fundoscopic abnormality to estimate the severity of HT were 59% and 60%, respectively (15). In the other side, although methods of ultrasonographic measurements of carotid IMT are not globally standardized, and it remains unclear whether conventional measurement of IMT represents TOD of HT, age and IMT were significantly associated with albuminuria, retinal arteriosclerosis, and left ventricular mass index in another study (16). Similarly, a multiple stepwise regression analysis showed that microalbuminuria depended on the following factors in nondiabetic but hypertensive patients: systolic BP, retinopathy, coronary heart disease, diastolic BP, and LVH in order of importance (p<0.0001 for all) (17). Additionally, degree of retinopathy was highly correlated with a mean 24-hour ABPM (r =0.31; p<0.0001), and left ventricular mass index was correlated with ABPM values but with a lower level of significance (r =0.19; p<0.001) compared to the degree of retinopathy (18). So ophthalmoscopy proved to be more sensitive than echocardiography in indexing 24-hour ABPM load while the more expensive echocardiography is not of great clinical value in borderline and mild HT cases (18). By using the Scheie's staging system, TOD of HT was found as an important factor for retinopathy in another study (19). Similarly, prevalences of grade I and II HRs were higher and grade 0 HR was lower in the HT group (p<0.001 for all) in a previous study of us (20).
As another supplementary finding to the hypertensive background of the retinopathy, there was no sign of persistent angiopathy in most normotensives, eventhough all of whom had suffered from HT in childhood in another study (14). Similarly, HT (mean BP of greater than 70 mmHg on three days) was noted in 1.2% of all neonatal admissions to intensive and intermediate care nurseries (21). Indirect ophthalmoscopy was performed in 21 neonates with elevated BP. Eleven of them demonstrated some or all of the following abnormalities, including increased ratio of venous to arterial caliber, vascular tortuosity (including arteriovenous crossing changes), and superficial and deep hemorrhages and exudates, but these findings appeared to resolve after controlling of HT. So HR may develop even in neonates and children in whom atherosclerosis of other causes is unlikely.
As a conclusion, although HR is not a specific sign of HT, the significantly lower prevalence of grade 0 and significantly higher prevalence of grade II HRs in the HT group indicate the effect of HT on retinal vasculature and probable benefits of funduscopic examination in the management of HT due to the limited number of available parameters in this field. Additionally, although the lower incidences and even additional atherosclerotic backgrounds of grade III and IV HRs, their specificity for HT is probably higher, especially for hypertensive crises. Therefore, funduscopic examination should be continued for HT at least until demonstration of some more accurate follow up criteria.