Analysis of the postoperative hemodynamic changes in varicose vein surgery using air plethysmography
Article Outline
Objectives
This study used air plethysmographic parameters to evaluate the changes in venous hemodynamics after the surgical treatment of primary varicose veins.
Methods
We retrospectively analyzed 1756 limbs of 1620 patients who had undergone surgery for great saphenous vein (GSV) reflux from January 1996 to June 2009 at Samsung Medical Center. Venous hemodynamic changes were evaluated by performing air plethysmography preoperatively and 1 month postoperatively and assessing the venous volume (VV), the venous filling index (VFI), the residual volume fraction (RVF), and the ejection fraction (EF).
Results
Preoperatively, median (interquartile range) values were VV, 121.6 (94.7-160.6) mL; VFI, 4.8 (2.9-7.6) mL/s; RVF, 40.6% (29.7%-50.0%); and EF, 53.5% (44.3%-64.1%). Postoperatively, the median (interquartile range) values were VV, 90.6 (69.1-116.8) mL; VFI, 1.4 (0.9-1.9) mL/s; RVF, 28.4% (17.5%-38.7%); and EF, 65.2% (54.5%-77.2%). VV, VFI, and RVF were reduced 25.2%, 71.5%, and 29.9%, respectively; EF was increased 20.3%. The results were significant for all four variables (P < .001). We compared the degree of hemodynamic changes according to the treatment modalities: the high ligation and stripping group , 1578 cases; the GSV valvuloplasty group, 124 cases; and the VNUS group (VNUS Medical Technologies Inc, San Jose, CA), 54 cases. The reduction of the VV, VFI, and RVF was greater in the GSV stripping group and in the VNUS group than in the valvuloplasty group (P < .001), yet no difference was noted in the EF increase among the surgical modalities (P = .157).
Conclusion
Our results show that the venous hemodynamic parameters of primary varicose veins were improved after surgical treatment.
The objectives of varicose vein tests are anatomic localization and quantification of the reflux. Ambulatory venous pressure (AVP) has been used for the evaluation of venous hemodynamics. AVP is measured by inserting a needle into a vein on the dorsum of the foot that is connected through a pressure transducer, and the hemodynamic parameters are measured. Because of invasiveness, it cannot be repeated frequently or be used as a screening test.
Air plethysmography (APG), first introduced by Christopoulos et al,1 is a noninvasive technique for measuring relative volume changes in the lower limb in response to postural alterations and muscular exercise. The results of APG correlate well with AVP, and it has been used for measuring the quantitative hemodynamic information of varicose veins.1, 2 APG can be used in conjunction with duplex ultrasound imaging to provide better information about venous function. Duplex ultrasound imaging is the most useful examination for evaluating venous valvular incompetence but provides relatively little quantitative hemodynamic information.3, 4, 5, 6, 7
Several studies have been shown that APG is useful to diagnose and quantify venous reflux and to evaluate the clinical severity of chronic venous insufficiency.4, 8, 9 APG provides reproducible hemodynamic measurements that can be evaluated noninvasively in serial examinations.1, 9 APG is now widely used for the preoperative examination of varicose veins, but only a few studies have compared the hemodynamic changes in varicose veins before and after operation.1, 10 Published results documenting comparative data of hemodynamic improvement between treatment modalities are limited.10, 11, 12, 13 This study was conducted to assess the early hemodynamic changes one month after varicose vein surgery by means of air plethysmography and to compare the hemodynamic changes according to the treatment modalities.
Methods
We operated on 2120 limbs of 1949 patients for primary varicose veins in Samsung Medical Center from January 1996 to June 2009. Among these patients, 1756 limbs of 1620 patients who underwent great saphenous vein (GSV) surgery were analyzed. We excluded patients with a history of deep vein thrombosis, congenital malformation, deep vein valvular insufficiency, previous venous surgery, or sclerotherapy. Because 99% limbs in this study were CEAP class C2 and only 1% limbs were C3 and C4, the C3 or C4 limbs were excluded due to disparity of sample size. Consequently, all of 1756 limbs were classified as C2EPASPR and the analysis was performed for these limbs.
Hemodynamic changes were assessed by the preoperative and postoperative differences of the APG variables of venous volume (VV), venous filling index (VFI), residual volume fraction (RVF), and ejection fraction (EF). Preoperative color Doppler ultrasound (CDU) imaging was performed in all patients by sonographers certificated by the American Registry for Diagnostic Medical Sonography. The examination was performed with the patient standing using a 5 to 9-MHz linear probe (Antares, Siemens, San Diego, Calif, and Logiq 9, GE Medical System,Waukesha, Wisc). Venous valvular insufficiency was examined for the superficial, deep, and perforating veins by using the manual calf compression maneuver. For diagnosis of venous reflux, the cutoff values >500 ms were used for all venous systems.14
The venous hemodynamic variables for all the limbs were assessed with APG (ACI300, ACI Medical Inc, San Marcos, Calif). The VV, the VFI, the RVF, and the EF were checked preoperatively and at 1 month postoperatively. Three certificated vascular examiners performed the examinations according to the standard protocol. The patient was fitted with an air-filled cuff, and the leg was elevated to about 45°. After the venous blood was emptied from the leg and a stable baseline had been reached, the patient quickly stood without putting any weight on the leg being studied and the parameters were recorded. The venous volume and filling time and the VFI on standing from the recumbent position were measured.
The time in seconds required to reach a stable plateau on the APG test is called the venous filling time, and the VFI was calculated by dividing the VV at 90% refilling by the venous filling time required to reach 90% refilling. The ejected volume (EV) and the ejection fraction (EF = EV × [100/VV]) with one tiptoe movement, and the residual volume and residual volume fraction (RVF = RV × [100/VV]) after 10 tiptoe movements were measured.1 In this study, the reference values were 100 to 150 mL for VV, <2 mL/s for VFI, <35% for RVF, and <60% for the EF.1, 9, 11
The surgical procedures included (1) high ligation and stripping (HL-stripping) of the GSV and varicosectomy, (2) external banding valvuloplasty of the GSV and varicosectomy using Dacron-tailored mesh (LARS Mesh, Meadox Medical Inc, Wayne, NJ), and (3) obliteration of the GSV using the VNUS system (VNUS Medical Technologies Inc, San Jose, CA, USA) and varicosectomy. Duplex scan mapping was performed preoperatively. All procedures were performed under spinal anesthesia or general anesthesia.
Statistical analysis was done with SPSS 17.0 software (SPSS Inc, Chicago, Ill). The descriptive data are reported as median and interquartile range (IQR). The change of the APG results after treatment was tested by the Wilcoxon signed rank test, and the difference of the results between the treatment modalities was tested by the Kruskal-Wallis test. Values of P < .05 were considered significant.
Results
We analyzed 1756 limbs of 1620 patients, consisting of 607 men (35%) and 1149 women (65%; male/female ratio, 1:1.9). The mean age was 49.1 years (IQR, 42-57 years).
According to the CEAP classification, 773 (44%) limbs were assigned to C2A (asymptomatic) and 983 (56%) limbs to C2S (symptomatic). All limbs had primary etiology and had reflux as their pathophysiology. For the reflux pattern of the CEAP classification, all the limbs had GSV insufficiency and 579 limbs (33%) had concomitant perforating vein insufficiency.
High ligation and stripping of the GSV and varicosectomy were done in 1578 limbs (90%). External banding valvuloplasty of the GSV and varicosectomy were performed in 124 limbs (7%). Obliteration of the GSV using VNUS and varicosectomy were done in 54 limbs (3%). Epifascial ligation was performed in the limbs with incompetent perforating veins.
The median (IQR) preoperative values in limbs with varicose veins were VV, 121.6 (94.7-160.6) mL; VFI, 4.8 (2.9-7.6) mL/s; RVF, 40.6% (29.7%-50.0%), and EF, 53.5% (44.3%-64.1%). The median (IQR) postoperative values were VV, 90.6 (69.1-116.8) mL; VFI, 1.4 (0.9-1.9) mL/s; RVF, 28.4% (17.5%-38.7%); and EF, 65.2% (54.5%-77.2%). The VV, VFI, and RVF were reduced 25.2%, 71.5%, and 29.9%, respectively. The EF was increased 20.3%. The results were significant for all four variables (P < .001; Table I).
Table I. Changes in venous hemodynamics before and after operation
| Variable | Preoperative Median (IQR) | Postoperative Median (IQR) | Reduction ratea % | Pb |
|---|---|---|---|---|
| VV, mL | 121.6 (94.7-160.6) | 90.6(69.1-116.8) | 25.2 | <.001 |
| VFI, mL/s | 4.8(2.9-7.6) | 1.4(0.9-1.9) | 71.5 | <.001 |
| EF, % | 53.5(44.3-64.1) | 65.2(54.5-77.2) | –20.3 | <.001 |
| RVF, % | 40.6(29.7-50.0) | 28.4(17.5-38.7) | 29.9 | <.001 |
aReduction rate, % = (1 – postoperative/preoperative) × 100. |
bWilcoxon signed rank test. |
We analyzed the hemodynamic variables according to the operation. The group that had HL-stripping of the GSV with varicosectomy showed a decrease in the VV, VFI, and RVF, and an increase in EF, and these changes were statistically significant (P < .001). These changes were also observed for the external banding valvuloplasty of the GSV with varicosectomy (valvuloplasty group) and the obliteration of the GSV using the VNUS system and varicosectomy (VNUS group). Their changes were also statistically significant (P < .001; Fig. 1).
Fig 1.
Changes of the hemodynamic parameters venous volume are shown before and after surgery according to the operative modalities. HL, High ligation.
We created the scatter plot using EF and VFI to determine how these variables were changed after surgery. Most of the dots were in the right lower quadrant preoperatively but were shifted to the left upper quadrant. Of the total limbs, the percentage of the VFI >2 mL/s was 89% preoperatively and improved postoperatively so that the percentage of the VFI <2 mL/s was 74% (Fig 2).
Fig 2.
Scatter plot shows hemodynamic changes in relation to the ejection fraction and venous filling index (Left) preoperatively and (Right) postoperatively.
In the HL-stripping group, the reduction rates of VV, VFI, and RVF were 25.9%, 72.6%, and 30.4%, and the increasing rate of EF was 21.4%. In the valvuloplasty group, the reduction rates of VV, VFI, and RVF were 14.2%, 60.7%, and 9.7%, and the increasing rate of EF was 14.7%. In the VNUS group, the reduction rates of VV, VFI, and RVF were 27.4%, 76.8%, and 35.5%, and the increasing rate of EF was 15.5%. All of these changes were statistically significant (P < .001).
As we compared the degree of reduction rates among the three operative modalities, the reduction rates of the VV, VFI, and RVF were higher in the HL-stripping group and in the VNUS group than those of the valvuloplasty group (P < .001). However, there was no difference of increasing rate of the EF among the surgical modalities (P = .157; Table II).
Table II. Difference of the reduction rates in the limbs with great saphenous vein reflux according to the operative modalities
| Reduction ratea | HL/stripping | Valvuloplasty | VNUS | Pb |
|---|---|---|---|---|
| Of VV, % | 25.9 | 14.2 | 27.4 | <.001 |
| Of VFI, % | 72.6 | 60.7 | 76.8 | <.001 |
| Of EF, % | –21.4 | –14.7 | –15.5 | .157 |
| Of RVF, % | 30.4 | 9.7 | 35.5 | <.001 |
aReduction rate (%) = (1 − postoperative/preoperative) × 100. |
bKruskal-Wallis test; the least significant difference using ranks for post hoc analysis. |
Discussion
The ultimate goal of treating varicose veins is to diminish the hemodynamic effect of the disease on the lower extremity and to relieve the patient of the symptoms of varicose veins. Various treatment options have been used to achieve this. Thus, objective testing for assessing the hemodynamic changes before and after treatment is meaningful.
AVP has been used as the hemodynamic standard in the development of noninvasive methods for screening and diagnostic evaluation. AVP has been supplanted by APG studies that indirectly measure the venous hemodynamics. After APG was introduced, several studies examined the role of APG and the implication of each of the variables in the diagnosis of chronic venous insufficiency.
The VV, which is the amount of blood in the venous reservoir, is reduced after varicose vein surgery.9, 15, 16 The VFI is a measure of the reflux flow through the incompetent venous valves and is considered a good predictor of venous reflux and a reliable indicator of calf pump function. The VFI is known as a parameter that correlated well with clinical outcome.15, 17 The EF and RVF are related to the function of the calf muscle pump.8, 11 Evaluation of the muscle pump function in patients with chronic venous disease is important because its impairment significantly contributes to the disease severity.18
In the present study, all the hemodynamic parameters were significantly improved after surgery in terms of reduction rates of the VV, VFI, RVF, and the increasing rate of the EF. The results represented an improvement in venous reflux, as demonstrated by a decrease in the VV and VFI. The favorable turns of the EF, RVF, and VFI suggest that the improvement in the overall function of the lower extremity venous function is associated not only with the abolition or venous reflux but also with the improved performance of the calf muscle pump. The measurements of venous reflux and calf pump function can be useful in determining the hemodynamic change responsible for varicose vein surgery. The EF and VFI measurements when used together have a good correlation with the severity.2 Overall hemodynamic changes were plotted on the graph in relation to the EF and VFI.
Although normalization was not achieved in all of the limbs postoperatively, most limbs did shift in a hemodynamically favorable direction. We determined that gross venous reflux and calf muscle pump function were improved after surgery. According to the results of the analysis that compared the degree of the hemodynamic changes among the treatment modalities, the HL-stripping group and the VNUS group showed a greater reduction of the VV, VFI, and RVF than the valvuloplasty group.
Conclusion
We assessed overall venous hemodynamic changes by APG before and after varicose vein surgery in patients with predominate GSV insufficiency. We found objective improvement of venous reflux and calf muscle function. We believe that the APG can well provide noninvasive, objective, and reproducible venous measurement before and after varicose vein surgery.
Author contributions
References
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Competition of interest: none.
The editors and reviewers of this article have no relevant financial relationships to disclose per the JVS policy that requires reviewers to decline review of any manuscript for which they may have a competition of interest.
PII: S0741-5214(09)02433-1
doi:10.1016/j.jvs.2009.11.061
© 2010 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.
