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Abstract

  1. Top of page
  2. Abstract
  3. Introduction
  4. Patients and Methods
  5. Results
  6. Discussion
  7. Author Contributions
  8. Acknowledgements
  9. References

Splenectomy is considered the second-line of treatment in patients with chronic primary immune thrombocytopenia (ITP) in whom glucocorticoids have failed. Some patients do not respond to splenectomy or they have postoperative complications. Based on our previous experience using kinetic and scintigraphic parameters, we did a retrospective study with the aim of comparing all these parameters as a means of predicting the success of splenectomy in persistent and chronic primary ITP. Forty-one consecutive patients with chronic primary ITP refractory to prednisone, who had been splenectomized, were included in the study. The response to splenectomy was assessed by evaluating bleeding and platelet counts before and at different times after surgery. A complete platelet kinetic study was performed before the splenectomy using autologous 111In-labeled platelets. The scintigraphic parameters measured included different indices between spleen/heart, liver/hearth, and spleen/liver. Thirty-six patients gave a complete response after splenectomy and five patients did not respond. A statistically significant difference between both groups was found with initial platelet recovery and with some scintigraphic indices which also showed a variable prediction value for the success of splenectomy. Among these indices, the spleen/liver at 30 minutes demonstrated a predictive value with a 100% of sensitivity and a 100% of specificity. Conclusion: some platelet kinetic parameters and scintigraphic indices, in particular the spleen/liver at 30 minutes, were useful to predict the outcome of splenectomy in persistent and chronic primary ITP and, therefore, they should be taken into account when deciding whether or not to perform a splenectomy. Am. J. Hematol. 2011. © 2011 Wiley-Liss, Inc.


Introduction

  1. Top of page
  2. Abstract
  3. Introduction
  4. Patients and Methods
  5. Results
  6. Discussion
  7. Author Contributions
  8. Acknowledgements
  9. References

Immune thrombocytopenia (ITP) is a disorder characterized by an accelerated platelet destruction, mainly in the spleen, caused by antiplatelet autoantibodies [1, 2]. Bone marrow megakaryocytes generally respond generating a higher number of platelets, but sometimes, the antibodies inhibit their thrombopoietic function. The typical picture of acute primary ITP is the sudden presentation of cutaneous purpura and/or mucous bleeding and severe thrombocytopenia with a favorable outcome [1, 3]. In the chronic form, the disease persists for more than 6 months [2, 4]. Moreover, some cases of ITP do not show the acute clinical episode and only present slight or moderate chronic bleeding; in this type of ITP, the thrombocytopenia might be an incidental finding [1].

When platelet counts are less than 30 × 109/L (considered the minimum haemostatic count) and there is a bleeding tendency, the first treatment of choice is prednisone (1 mg/Kg/day). Prednisone achieves a complete or partial short-term response in 50–90% of patients, but only about 30–60% of responders have a long-term response [1, 2, 5–8].

Some authors consider that splenectomy is the best treatment for chronic primary ITP; indeed, before the introduction of prednisone, splenectomy was the only treatment for the disease [2, 9]. From the beginning of the 2000s, rituximab has been successful for treating ITP and, more recently, a new approach using thrombopoietic factors seems to be promising [10, 11]. However, today, splenectomy is still considered the second-line of treatment when prednisone fails, when the doses required for maintaining a haemostatic platelet count is unacceptably high, or when the side effects are severe [1, 3–6, 12]. Moreover, as the spleen is not only the main site of platelet destruction, but is an organ containing autoantibody-producing B-cells, splenectomy is also a curative treatment [1, 3].

The evaluation of the response to splenectomy includes the increase of platelet counts and the reduction of bleeding at different periods of time after surgery [4, 13–15]. The success of splenectomy in primary ITP is estimated to be about 60–80% in the different series of cases studied [2, 7–9, 16]. However, this surgical procedure involves 0–24.3% morbidity, and 0–6.0% mortality [17, 18]. Laparoscopic splenectomy is a safer procedure and has several advantages as compared to open splenectomy. The patients have less discomfort, lower morbility and earlier recovery [7, 19]. However, postoperative complications (wound infections or dehiscences, hemorrhages, pancreatic fistulas or edema, pneumonia or pleuritis, pulmonary thrombosis) may occur (0–23.5%), although less often than in open splenectomy. Moreover, it seems that mortality is not definitely reduced when laparoscopy (0–4.7%) is compared to open splenectomy. The major cause of perioperative death is intrabdominal bleeding, mainly in patients with severe thrombocytopenia [9, 17–20]. Overwhelming bacterial sepsis, mainly pneumococcal, and thrombosis are long-term complications that may occur also with laparoscopy [2, 5, 9].

With the aim to improve the success of splenectomy, the predictive value of several clinical and biological parameters has been investigated (age, sex, response to prednisone, or postsplenectomy platelet counts) and gave variable results [2, 9, 18, 19]. The predictive value of the platelet kinetic parameters has been analyzed also, including mean platelet lifespan, initial platelet recovery, and platelet production rate (PPR) or turnover [8, 21].

A systematic review to assess the long-term responses to splenectomy in primary ITP as well as the complications related to surgery was published by Kojouri et al. [9]. None of the preoperative characteristics (age, previous response to glucocorticoids or intravenous immunoglobulins, etc.) predicted the response to splenectomy. In contrast, there was a significant consensus in considering that the scintigraphic proof of the spleen as the main site of platelet destruction was the most valuable parameter for predicting a favorable outcome of splenectomy. Different scintigraphic indices have been proposed for this evaluation, such as spleen/liver [15, 22–24], spleen/heart [14] and spleen/spleen [13, 25] at different times after the injection of autologous 111In-platelets. All of them exhibited some predictive value but there was not one parameter with a high level of prediction.

The platelet kinetic parameters and scintigraphic indices have been used in our hospitals for years to know if there was increased destruction of platelets and whether or not the destruction pattern was mainly splenic. The final decision to perform splenectomy, as a second-line treatment, was made considering both the pattern of platelet destruction and the clinical condition. In recent years, we have noticed that the scintigraphic index spleen/liver at 30 minutes (S/L-30) predicted the outcome of splenectomy in a number of patients, because of its capacity to represent the pattern of platelet destruction. Therefore, the aim of the present study was to analyze the predictive value of this index compared with other scintigraphic indices and with the platelet kinetic parameters in predicting the success of splenectomy in chronic primary ITP.

Patients and Methods

  1. Top of page
  2. Abstract
  3. Introduction
  4. Patients and Methods
  5. Results
  6. Discussion
  7. Author Contributions
  8. Acknowledgements
  9. References

Patients

A total of 41 consecutive patients that underwent splenectomy for chronic primary ITP were included in our study. All of the data were taken retrospectively from the Hospital de Bellvitge (L'Hospitalet de Llobregat, Barcelona, Spain) clinical archives. The study was performed according to the principles outlined in the Declaration of Helsinki of 1975, and all procedures were approved by the Ethics Committee of the Hospital de Bellvitge.

For the diagnosis of primary ITP, the exclusion of other causes of thrombocytopenia was required: malignant or deficitary hemopathy, aplasia, hepatopathy and/or hypersplenism, disseminated intravascular coagulation or thrombotic thrombocytopenic purpura, alloimmune, genetic or drug-related thrombocytopenias, and pseudothrombocytopenia. In addition, one of the following inclusion criteria was also required: (1) the finding of antiplatelet antibodies fixed on the platelet surface, demonstrated in the eluate by the indirect platelet immunofluorescence test [26], or (2) a platelet kinetic study demonstrating an increased platelet destruction, based on a shorter than normal platelet lifespan. The cases of secondary ITP, associated with other disorders, were not included.

All patients had been treated previously with standard doses of oral prednisone (1–1.5 mg/Kg/day) for a minimum of 2–4 weeks as first-line treatment. Prednisone was always tapered gradually during a minimum period of 12 weeks. The patients were considered refractory to prednisone when after one or two courses of treatment the response was incomplete, transitory or null, or they presented severe side effects. Then, the platelet kinetic study was performed, if it was not performed previously. The decision to perform the splenectomy as second-line treatment was based on the kinetic and scintigraphic parameters, mainly the platelet destruction pattern (splenic or not), and the clinical aspects. The general and hematological characteristics of the patients are described in Table I.

Table I. Clinical Characteristics of Patients, Including Pre-and Postsplenectomy Platelet Counts, and Response to Splenectomy
PatientAgeSexPAAPC prePC postResponse
  1. Sex: M, male; F, female; PAA, platelet autoantibodies and its Ig class; PC, platelet counts (×109/L) pre-splenectomy and 3 months post-splenectomy; CR, patients with complete response; NR, patients with no response.

167FIgM26278CR
239MIgM35130CR
365F51251CR
452F3012NR
532M43338CR
647M23338CR
766MIgM59200CR
872MIgG + IgM12126CR
972MIgM19370CR
1041F15537CR
1171F17315CR
1251M15430CR
1334MIgM20282CR
1455M40170CR
1518F1445CR
1656F315NR
1729MIgG4132NR
1862MIgG59264CR
1924MIgM45154CR
2065F6312CR
2131M4357CR
2258M16347CR
2370M36434CR
2422M14301CR
2571F24283CR
2671FIgG24214CR
2747MIgM17133CR
2819FIgG35344CR
2936FIgG + IgM77305CR
3049M2542NR
3153M2130NR
3216F28651CR
3321MIgG89452CR
3430F27515CR
3519M48304CR
3649M65403CR
3718M53507CR
3833M99250CR
3946MIgG + IgM15192CR
4038FIgG2277CR
4151MIgG26124CR

Evaluation of the response to splenectomy

The controls were assayed at 24–48 hrs, 7 days, 30 days, 3 months, 6 months, and 12 months, and the assay included a clinical evaluation of bleeding and a platelet count. The results were compared to the baseline parameters obtained before splenectomy.

For evaluating the quality of the response to splenectomy we applied the criteria established by an International Working Group [27] that defined three types of response: (1) Complete response (CR): platelet count ≥ 100 × 109/L and no bleeding; (2) Response: platelet count ≥ 30 × 109/L, or at least twofold of the baseline count, and no bleeding; (3) No response (NR): platelet count < 30 × 109/L, or less than twofold of the baseline count, or persistence of bleeding. Using this criteria, 36 (87.8%) of our patients had a successful outcome, all of them with a CR response, and 5 (12.2%) did not respond and were classified as NR (Table I).

Platelet kinetic procedures

A complete platelet kinetic study was performed on all the patients before splenectomy, using autologous 111In-labeled platelets. The labeling procedure has been described in detail previously [28] and was based on the method of Thakur et al. [29]. Briefly, platelet-rich plasma was obtained from 68 mL of blood, collected with 18 mL of ACD-A, after a sedimentation step (10 min) and a slow centrifugation (180g × 15 min). The platelet pellet was isolated from platelet-rich plasma after its rapid centrifugation (640g × 10 min). Platelets were washed and resuspended in a modified Thyrode solution and then they were incubated with 4 MBq of 111In-oxine for 10 min at 37°C. After incubation, the platelets were washed and resuspended in 4 mL of platelet-poor plasma. Labeling efficiency was measured and a standard of 111In-oxine was made to calculate the initial platelet recovery.

Measurement of kinetic parameters

  • Platelet survival time was determined from radioactive counts of 5 mL venous blood obtained at 30 min, 2, 4, 6, 24, 48, 72, and 144 hr postinjection. A multiple hit method was used to calculate the mean platelet survival following the International Committee for Standardization in Hematology (ICSH) [30]. The normal values range from 7.3 to 9.5 days.

  • Initial labeled platelet recovery was defined as the value at the y-intercept radioactivity (zero time) obtained by back-extrapolation [30]. The normal values range from 55 to 72% of the dose injected, owing to pooling of about one-third of the platelets in the spleen and in the liver [31].

  • PPR was defined as the number of platelets released into the circulation per unit of time. It was calculated from the platelet survival time, the initial platelet recovery and the blood platelet count. The normal values range from 28.8 to 38.4 × 109 platelets/L/day [22].

Measurement of scintigraphic parameters

The images were taken by means of a gamma camera using a medium-energy collimator and the 173 and 247 keV photo peaks. The images were acquired at 30 min, 24, 48, and 72 hr after the injection of 111In-platelets; the acquisition time was 10 min per view. Anterior and posterior images of the spleen, liver and heart were obtained, and regions of interest (ROI) were drawn to encompass the contours of the spleen, liver and heart respectively. Geometric means of the average ROI counts were calculated using anterior and posterior values to represent radiolabel platelet uptake by the spleen, liver and heart. The following scintigraphic indices were obtained:

  • Spleen/Heart indices (S/H): (1) the ratio between the spleen uptake and the heart uptake, both obtained at 30 min postinjection of the radiolabelled platelets (S/H-30), (2) the highest value of the ratio between the spleen uptake and the heart uptake, obtained at the same time (S/H-max), and (3) the ratio between S/H-max and S/H-30 (S/H-max/S/H-30).

  • Liver/Heart indices (L/H), and Spleen/Liver indices (S/L): The definition, nomenclature and measurement system of these indices were equivalent to the S/H indices.

  • Spleen/Spleen at 30 min index (S/S-30): This index is the highest value of the ratio between the spleen uptake obtained at 24, 48, and 72 hr, and the spleen uptake obtained at 30 min postinjection of the radiolabelled platelets.

  • Liver /Liver at 30 min index (L/L-30): The definition, nomenclature and measurement system of this index was equivalent to the S/S index.

Statistical analysis

We applied a parametric test of One-way Analysis of Variance, if Normality Test and Equal Variance Test passed; otherwise we used a nonparametric test of One-way Analysis of Variance on Ranks. The Sigma Stat Program was used to perform these tests.

The sensitivity and specificity for predicting the success of splenectomy were established for the parameters that demonstrated significant differences between CR and NR patients. For the kinetic parameter calculations, the lower levels of the normal ranges were taken as the predictive values. In contrast, in the scintigraphic indices, the values that showed 100% sensitivity were taken as predictive values and then its specificity was determined.

Results

  1. Top of page
  2. Abstract
  3. Introduction
  4. Patients and Methods
  5. Results
  6. Discussion
  7. Author Contributions
  8. Acknowledgements
  9. References

Neither age, sex, platelet count, detection of antiplatelet antibodies, nor the type of antibody detected, were statistically different between CR and NR patients.

The results of kinetic and scintigraphic parameters are shown in Table II. All of the patients had a platelet survival shorter than normal; there was no statistical difference between CR and NR patients. Twelve patients (4 of them NR) had a platelet recovery shorter than normal and one patient (CR) had a platelet recovery higher than normal; there was a statistically significant difference (P = 0.001) between CR and NR patients. Four patients (2 of them NR) had a PPR shorter than normal, and 11 patients (10 of them CR) had a PPR higher than normal; there was no statistical difference between CR and NR patients. Several scintigraphic indices showed significant differences between CR and NR patients. Among them, S/H-max/S/H-30, L/H-30, L/H-max, S/L-30, and S/L-max. However, there was no significant differences between the S/S-30 index of CR patients (mean 1.6, standard deviation 0.4) and NR patients (mean 1.4, standard deviation 0.3), and between the L/L-30 of CR patients (mean 1.2, standard deviation 0.5) and NR patients (mean 1.2, standard deviation 0.4).

Table II. Platelet Kinetic and Scintigraphic Results Before Splenectomy (Mean ± Standard Deviation and Minimum–Maximum Values) and Response to Splenectomy
ParametersCR (n = 36)NR (n = 5)P-value
  1. CR, patients with complete response; NR, patients with no response; PPR, platelet production rate or turnover; SH, spleen/heart indices; L/H, liver/heart indices; S/L, spleen/liver indices; Index-30, ratio at 30 minutes; Index-max, maximum ratio obtained; ns, nonsignificant.

Platelet survival (days)2.0 ± 1.50.7 ± 1.4ns
Platelet recovery (%)62.7 ± 18.136.3 ± 14.00.001
PPR (platelets × 109/L/day)50.1 ± 31.686.5 ± 130.0ns
S/H-306.4 ± 2.5 (2.9–13.1)5.0 ± 3.7 (1.9–10.5)ns
S/H-max16.4 ± 10.2 (3.2–54.3)7.5 ± 5.2 (3.7–15.3)ns
S/H-max/S/H-302.5 ± 1.1 (0.8–4.5)1.6 ± 0.2 (1.4–1.9)0.02
L/H-302.2 ± 1.2 (0.8–6.0)10.0 ± 7.0 (2.6–18.8)0.003
L/H-max3.8 ± 2.7 (1.0–11.9)11.4 ± 6.4 (3.9–20.3)0.003
L/H-max/L/H-301.6 ± 0.6 (0.9–3.9)1.4 ± 0.7 (1.0–2.6)ns
S/L-303.3 ± 1.4 (1.3–5.9)0.7 ± 0.4 (0.2–1.1)<0.001
S/L-max6.2 ± 3.9 (0.4–16.7)0.8 ± 0.5 (0.3–1.6)0.001
S/L-max/S/L-301.8 ± 0.9 (0.3–3.7)1.4 ± 0.6 (0.6–2.1)ns

The lower normal limit for initial platelet recovery (≥55%) gave a predictive value of 96.7% for the success of splenectomy with a specificity of 80.5% (Table III). The same predictive value was obtained for a platelet recovery value of ≥40%; in this case, the specificity was higher: 88.9%. The predictive values of the scintigraphic indices for the success of splenectomy with a sensitivity of 100% as well as its specificity are also exposed in Table III.

Table III. Sensitivity and Specificity of the Kinetic and Scintigraphic Parameters that Have Shown Statistical Significant Differences Between Patients with Complete Response and Patients with No Response to Splenectomy
ParametersPVSensitivity (%)Specificity (%)
  1. PV, predictive value for the success of splenectomy established for each parameter; SH, spleen/heart indices; L/H, liver/heart indices; S/L, spleen/liver indices; Index-30, ratio at 30 minutes; Index-max, maximum ratio obtained.

Initial platelet recovery≥55%96.780.5
Initial platelet recovery≥40%96.788.9
S/H-max/S/H-30≥1.910072.2
L/H-30≥2.610077.8
L/H-max≤3.910069.4
S/L-30≥1.1100100
S/L-max≥1.610086.1

Discussion

  1. Top of page
  2. Abstract
  3. Introduction
  4. Patients and Methods
  5. Results
  6. Discussion
  7. Author Contributions
  8. Acknowledgements
  9. References

The predictive value of several clinical and biological parameters for the success of splenectomy in chronic primary ITP has been investigated previously. For example, some reports indicate that young age is a predictor of success, but this is not replicated in other reports [2, 7, 9]. On the other hand, sex, time elapsed between diagnosis and splenectomy [7, 8] and time required to obtain the prednisone response [7, 19] did not have any predictive value. In our study, age, sex, detection of autoantibodies on the platelet surface and immunoglobulin class of these antibodies, had no predictive value.

Some correlation between the reduction of platelet survival time and the success of splenectomy has been reported, but these results were not statistically significant [21]. Likewise we found no correlation. Some authors [32] reported good response after splenectomy in patients with normal or increased PPR and decreased platelet survival time in comparison with patients who had decreased PPR and relatively less decreased platelet survival time. However, other authors [8] reported that an increase in the PPR affected the success of prednisone therapy, but this effect was not demonstrated with splenectomy. In our study, we did not find a significant difference between the PPR in CR patients and in NR patients.

The site of platelet destruction has been studied extensively as regards predicting the efficacy of splenectomy. This parameter is obtained by measuring the splenic and liver uptake of radiolabelled platelets at different times after injection. In normal individuals, the splenic activity remains constant over several days and this is interpreted as an indication of a dynamic equilibrium between destruction and pooling within the spleen. The increase of the platelet splenic uptake is defined as a progressive increase of radioactivity over the spleen for the duration of platelet survival time, corrected or not for the pooled platelet activity [33].

Using a solid crystal collimated probe, Najean et al. [34] measured the splenic, hepatic and precordial areas and analyzed the variation of the scintigraphic S/H and L/H indices and the increase between the S/L-30 and the S/L at the time that 80% of the circulating platelets were destroyed. These parameters were used to classify the patients according to the site of platelet destruction. Later, they studied the response to splenectomy in 268 ITP patients using this classification [14]. The results of splenectomy were excellent in 96.0% of the patients with exclusively splenic platelet destruction and successful in only 15.4% of the patients with predominantly or exclusively hepatic platelet destruction. However, these results are not exactly the same of those obtained with a gamma camera instead of a collimated probe; the gamma camera is the method universally used by almost all authors in the last 25 years. In fact, the dynamic images obtained with the patient supine and positioned above a gamma camera or anterior and posterior static views of each organ allows for more complete information of the radioactive uptake from each organ. Our scintigraphic results, obtained with a gamma camera, demonstrated that among the S/H indices, only the ratio between S/H-max and S/H-30 provided statistically significant differences between CR and NR patients (Table II). Moreover, the values greater than 1.9 of this ratio were only found in CR patients indicating a sensitivity of 100% as a predictive value for the success of splenectomy with a specificity of only 72.2% (Table III).

Among L/H indices, LH-30 and L/H-max provided significant differences between CR patients and NR patients (Table II). L/H-30 values below 2.6, and L/H-max values below 3.9 were found only in CR patients indicating a sensitivity of 100% for these indices. However, the specificities obtained were lower (Table III).

The S/L indices obtained at different times after the injection of the radiolabel platelets have been the parameters most used to predict the outcome of splenectomy. However, the lack of a methodology for labeling the platelets and of a unified standardization of the methods of obtaining this index have led to results that are not easy to compare. So, Siegel et al. [22] proposed the S/L at 24 hr postinjection and found a good response to splenectomy when this ratio was >1.2. They hypothesized that those patients in whom the primary mechanism of thrombocytopenia is rapid destruction benefits greatly from the removal of the spleen. Conversely, patients with moderately decreased platelet survival and impaired production benefit little from the splenectomy.

Other authors described other predictive indices. One of them, the S/L at 24 hr index, demonstrated a good prognostic for splenectomy when its value was >3 [23]. Another index was the normalized S/L ratio (S/L at 192 hr)/(S/L at 1 hr). It showed a significant difference between responder and nonresponder ITP patients to partial splenic embolization, but there was a substantial overlap among the individuals [15]. The proportion between the maximum increase in splenic platelet uptake and the maximum increase in liver platelet uptake [35] was also studied. After splenectomy, persistent relapse occurred in patients with lower S/L, but this result was not significantly different from those found in patients with a persistent response.

Recently, Sarpatwari et al. [24] applied the S/L ratio described by Najean et al. [34] in 72 patients after splenectomy. Between 6 and 12 month postsurgery a CR was observed in 87.0% of the patients with a purely or predominantly splenic destruction pattern and only in 27.8% of the patients with a mixed or hepatic destruction pattern.

Our results demonstrated that S/L indices were the most useful parameters in predicting the success of splenectomy, particularly the S/L-30 index. The values of S/L-30 were significantly different between CR patients and NR patients (Table II) and values of S/L-30 > 1.1 were found only in CR patients; this demonstrated a sensitivity of 100%. Moreover, values >1.1 were found in all CR patients indicating that the specificity of this index was also 100% (Table III). S/L-max values showed significant differences between CR patients and NR patients, and a result of S/L-max > 1.6 was found only in CR patients (sensitivity 100%) but its specificity was 86.1%.

Scintigraphic indices comparing different activities in the same organ, spleen or liver, have been published as predictive factors for splenectomy. For example, the values of S/S-30 and L/L-30 indices were used to establish the predominant uptake site of platelets: splenic (S/S-30 > 1.2), hepatic (L/L-30 > 1.2) or mixed (S/S-30 and L/L-30 > 1.2) [13]. The majority of splenectomized patients with a splenic pattern obtained a CR. In contrast, the patients with a hepatic or mixed pattern showed an opposite result with a significant difference. Using the S/S and L/L indices we did not find any difference between CR and NR patients.

Other authors do not use scintigraphic indices to detect the site of platelet sequestration. One study [32] analyzed the increase of splenic and hepatic uptake by recording at every 60 one-minute frames, immediately after injection of labeled platelets, with a large-field-of-view gamma camera. These views were repeated several times up to the fifth day. However, the results of this study failed to predict the response to splenectomy in a group of chronic primary ITP patients.

After reviewing the literature, we have not found any publication about the initial platelet recovery as a predictive value for the success of splenectomy. In our study, the differences between CR and NR patients were statistically significant, and taking the values ≥40% as predictive for the success of splenectomy, both the sensitivity (96.7%) and the specificity (88.9%) were very high (Table III).

We have not found any study comparing the value of the different scintigraphic indices in predicting the success of splenectomy. In our study we obtained the predictive values for all of the indices that demonstrated significant differences between CR and NR patients (Table III). To find the best predictive value for each index, first, we searched the values that showed the 100% of sensitivity, i.e. those that occurred in all of the CR patients, and second, we calculated the specificity. We obtained the most interesting result with the SL-30 index that showed statistically significant differences between CR and NR patients and, moreover, it could predict the success of splenectomy with a 100% sensitivity and a 100% specificity. The predictive values found for the SL-30 index were those ≥1.1. These values represented the increased and progressive accumulation of platelets in the spleen together with a normal recruitment in the liver, demonstrating that the predominant destruction site of labeled platelets was the spleen.

In conclusion, our study showed that some platelet kinetic and scintigraphic parameters can help to predict the outcome of splenectomy in chronic primary ITP. The parameters that were useful were: initial platelet recovery, S/H-max/S/H-30, L/H-30, L/H-max, S/L-30, and S/L-max. It should be pointed out that, among them, the S/L-30 index gave the best results. We recommend the use of the S/L-30 index to predict the success of splenectomy since the difference between CR and NR patients was statistically significant and it showed 100% sensitivity and 100% specificity. The computation of the scintigraphic indices can increase the efficiency and diagnostic value of the kinetic study with 111In-platelets for predicting the success of splenectomy in persistent and chronic primary ITP.

Author Contributions

  1. Top of page
  2. Abstract
  3. Introduction
  4. Patients and Methods
  5. Results
  6. Discussion
  7. Author Contributions
  8. Acknowledgements
  9. References

M.R. and N.P.-M. coordinated the research, and wrote the article. J.M., I.R.-Z., O.R., I.R., and N.P.-M. (from the centers associated in the Catalan Network for Platelet and Megakaryocyte studies) recruited the patients. E.M.D. performed the immunohematologic analyses. J.M., M.R., and I.R.-Z. participated in the scintigraphic work. I.R.-Z. and M.R. participated in the statistical analyses.

Acknowledgements

  1. Top of page
  2. Abstract
  3. Introduction
  4. Patients and Methods
  5. Results
  6. Discussion
  7. Author Contributions
  8. Acknowledgements
  9. References

The authors thank Dr. Blanca Jimenez from the Servei Català de la Salut and Universitat Autònoma de Barcelona, Spain, for her technical help.

References

  1. Top of page
  2. Abstract
  3. Introduction
  4. Patients and Methods
  5. Results
  6. Discussion
  7. Author Contributions
  8. Acknowledgements
  9. References
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