|Year : 1992 | Volume
| Issue : 3 | Page : 169-172
Digital blood flow in systemic sclerosis
Sanjay Ghosh, A Biswas
Source of Support: None, Conflict of Interest: None
Digital vascular status in 10 untreated patients suffering from systemic sclerosis for 1 to 4 years was evaluated by a method called photoplethysmography (PPG). The PPG probe was attached serially to the distal phalanges of all the digits of four limbs with Velcro-strap at an ambient temperature of 28° C - 32° C and humidity of 60-65 percent to record PPG tracings. Six patients (Group A) had clinical symptoms and signs of vascular impairment whereas 4 patients (Group B) did not have. Diminished vascular flow was seen in all the patients of both the groups. On an average, 9 digits (45%) in Group A and 7 digits (35%) in Group B had reduced blood circulation. The difference between the two groups was not statistically significant (p>0.5). Degree of vascular impairment had no bearing upon the duration of the disease (rxy=+0.41). Impairment of digital blood flow may be due to organic narrowing of digital artery, functional vasomotor changes, endothelial proliferation and damage, blood hyperviscocity and less deformable red blood cells.
Keywords: Systemic sclerosis, Vascular changes, Photoplethysmography(PPG)
|How to cite this article:|
Ghosh S, Biswas A. Digital blood flow in systemic sclerosis. Indian J Dermatol Venereol Leprol 1992;58:169-72
| Introduction|| |
Vascular abnormalities have been implicated in the pathogenesis of systemic sclerosis.  Vascular manifestations are. frequently shown by the disease.  Digital blood vessels are particularly prone to be involved as represented clinically by Raynaud's phenomenon, periungual telangiectasia, ulceration at digital tips and sclerodactyly in this disease.  Electron microscopic examination revealed significant changes in small blood vessels in early stage of systemic sclerosis even when light microscopy showed no vascular changes.  Nevertheless, the dynamic visualisation of blood flow rather than biopsy or autopsy studies is more informative to assess the exact vascular status in the diseased state. Studies in digital arteriography  and nail-fold capillary abnormalities by capillary microscopy  in systemic scleroderma were memorable ventures in this pathway and yielded valuable results confirming vascular aetiopathogenesis of the di,ease. It was in this context that the present investigation was designed to assess the digital capillary flow in systemic scleroderma with or without obvious clinical vascular symptoms and signs by a highly sensitive, non-invasive method called photoplethysmography (PPG).
| Materials and Methods|| |
10 Untreated patients (7F,3M) of systemic sclerosis, age ranging from 22 to 46 years, were included in the study. They suffered from the disease' for 1 to 4 years.
Among them, 6 subjects (Group A) had certain obvious clinical symptoms and signs indicating vascular impairment whereas the rest 4 subjects (Group B) had no such clinical feature. Diagnosis of all the cases were confirmed as systemic sclerosis by scleroderma criteria (major or minor) of American Rheumatism Association  alongwith correlating histopathological, radiological and laboratory investigations.
Photoplethysmography (PPG) is recorded by a device (Vaslab-IV, Vascular recorder, designed by Messers Kodys, Madras, India) which possesses a probe containing a diode to emit infra-red light and an adjacent photosensor to absorb reflected light. The result is obtained graphically on a strip-chart. 
In the study method, PPG probe was attached with the supplied velcro-strap to the distal phalanges of all the fingers and toes one by one. The size (gain) control was adjusted to have stylus deflection for the pulse wave of about 20-25 mm and kept unchanged for each digit. The study was conducted at an ambient temperature of 28 ° C-32 ° C and humidity of 60-65 percent.
| Results|| |
Normal (Control; in non-diseased persons) [Figure - 1] and abnormal [Figure - 2][Figure - 3][Figure - 4][Figure - 5] PPG graphs of digital capillary flow in certain representative cases have been furnished herewith. The results have been tabulated in [Table 1].
Critical (almost `zero') digital blood flow was seen in one patient of Group A [Figure - 2] and another in Group B [Figure - 4]. Still they had no sign of gangrenous change in the affected digits with critical flow.
Diminished vascular flow was seen in all the patients of both the groups in various number of digits. On an average, 9 digits (45%) in Group A and 7 digits (35%) in Group B patients showed reduced capillary flow. Chi square (x 2) test revealed that the difference between the two groups is not statistically significant (p > 0.5). Degree of vascular impairment had no correlation with the duration of the illness (correlation co-efficient r xy=+ 0.41) as shown in [Table 2].
| Comments|| |
Our study depicted that in all systemic scleroderma patients digital vascular flow was impaired independent of the fact that whether they had clinical vascular symptoms and signs or not. This observation can be substantiated by the previous works in this field. The occlusion of digital arteries through endothelial proliferation can often be demonstrated in early stages of systemic scleroderma.  Functional vasomotor changes are also frequently seen in the digital vessels in this disease. Blood hyperviscosity commonly occurs in scleroderma and thus increases the resistance to blood flow through narrowed vessels. Red blood cells from patients with systemic sclerosis are less deformable than normal.  Digital arteriography  also confirmed organic narrowing of the digital arteries in systemic scleroderma.
The present study revealed that the duration of the disease had no relation with the degree of vascular impairment. This finding also corroborates with the nail fold capillary microscopic observations  which showed no correlation between the disease severity or duration and the degree of capillary change.
The endothelial cells in systemic scleroderma may be the primary target of the disease-process. A reduction in number of capillaries and the presence of large gaps in between the endothelial cells have been described and a circulatory factor toxic for endothelial cells has been suggested. These vascular changes appear to occur early in the course of disease  The aetiology of reduction in capillary numbers in systemic sclerosis is unknown, but may be related to frequent capillary thromboses as observed in the nail fold by capillary microscopy. Such thromboses lead to micro-infarcts that heal by scarring.  Electron microscopical observations showed reduplication of the basement membrane, vacuolar degeneration, widened intercellular gaps and ultimate destruction of endothelial cells. Endothelial cell damage appears to precede the stage of fibrosis.  The result of our study also supports firmly the theory of vascular disorder as primary event in the aetiopathogenesis of systemic sclerosis.
Critical, i.e., almost `zero' blood flow in capillaries was seen in digits of certain patients without having obvious features of vascular obstruction. Hence, PPG, if . available, should be done in each case of systemic scleroderma to detect the impending gangrene of the digits in early phase.
Our study concludes that PPG is an objective, non-invasive and highly sensitive qualitative method of detecting digital vascular impairment in systemic scleroderma
| References|| |
|1.||Barun-Falco 0, Plewig G, Wolff H H, Winkelmann R K. Dermatology, 3rdedn. Berlin: Springer-Verlag, 1991; 556-62. |
|2.||Spittell Jr J A. Raynaud's phenomenon and allied vasospastic conditions. In: Peripheral Vascular Diseases (Fairbairn J F, Juergens J L, Spittell Jr J A, eds), 4th edn. Philadelphia: W B Saunders, 1972; 405-11. |
|3.||Falanga V. Scleroderma Syndromes. In: Principles and Practice of Dermatology, (Sams Jr WM, Lynch PJ, eds), 1st edn. New York: Churchill Livingstone, 1990; 589-94. |
|4.||Fleischmajer R, Perlish JS. Capillary alterations in scleroderma. J Amer Acad Dermatol, 1980; 2:161-70. |
|5.||Dabich L, Bookstein J J, Zweiflen A, Zarafenetics CJD. Digital arteries in patient with scleroderma- Arteriographic . and Plethysmographic study. Arch Int Med, 1972; 130: 708-14. |
|6.||Statham BN, Rowell NR. Quantification of the nail fold capillary abnormalities in systemic sclerosis and Raynaud's syndrome. Acta Dermatol Venereol, 1968; 66 : 139-43. |
|7.||American Rheumatism Association. Preliminary criteria for the classification of systemic sclerosis (scleroderma). Subcommittee for scleroderma criteria of the American Rheumatism Association diagnostic -and therapeutic criteria committee. Arthritis rheum, 1980; 23: 581-90. |
|8.||Ryan T J, Cherry G W. The assessment of vascular abnormalities of leg. In: Recent Advances in Dermatology, (Champion R H, ed), Number 7. Churchill Livingstone, 1986; 87-101. |
|9.||Rowell N R. Lupus erythematosus, Scleroderma and Dermatomyositis, The 'Collagen' or 'Connective Tissue' Diseases. In : Textbook of Dermatology (Rook A, Wilkinson DS, Ebling F J G, et al, eds), 4th edn. Bombay : Oxford University Press, 1987; 1347-66. |
|10.||Haustein U F, Hermann K, Bohme R J. Pathogenesis of Progressive Systemic Sclerosis. Internat J Dermatol, 1986; 25: 286-93. |
[Figure - 1], [Figure - 2], [Figure - 3], [Figure - 4], [Figure - 5]