Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Meta-Analysis
. 2015 Jun 29;2015(6):CD009648.
doi: 10.1002/14651858.CD009648.pub3.

CHIVA method for the treatment of chronic venous insufficiency

Sergi Bellmunt-Montoya  1 , Jose Maria Escribano, Jaume Dilme, Maria José Martinez-Zapata
Affiliations
Meta-Analysis

CHIVA method for the treatment of chronic venous insufficiency

Sergi Bellmunt-Montoya et al. Cochrane Database Syst Rev. .

Update in

  • CHIVA method for the treatment of chronic venous insufficiency.
    Bellmunt-Montoya S, Escribano JM, Pantoja Bustillos PE, Tello-Díaz C, Martinez-Zapata MJ. Bellmunt-Montoya S, et al. Cochrane Database Syst Rev. 2021 Sep 30;9(9):CD009648. doi: 10.1002/14651858.CD009648.pub4. Cochrane Database Syst Rev. 2021. PMID: 34590305 Free PMC article.

Abstract

Background: Many surgical approaches are available to treat varicose veins secondary to chronic venous insufficiency. One of the least invasive techniques is the ambulatory conservative hemodynamic correction of venous insufficiency method (cure conservatrice et hémodynamique de l'insuffisance veineuse en ambulatoire (CHIVA)), an approach based on venous hemodynamics with deliberate preservation of the superficial venous system. This is an update of the review first published in 2013.

Objectives: To compare the efficacy and safety of the CHIVA method with alternative therapeutic techniques to treat varicose veins.

Search methods: The Trials Search Co-ordinator of the Cochrane Peripheral Vascular Diseases Group searched the Specialised Register (April 2015), the Cochrane Register of Studies (2015, Issue 3) and clinical trials databases. The review authors searched PubMed (April 2015). There was no language restriction. We contacted study authors to obtain more information when necessary.

Selection criteria: We included randomized controlled trials (RCTs) that compared the CHIVA method versus any other treatments. Two review authors independently selected and evaluated the studies. One review author extracted data and performed the quantitative analysis.

Data collection and analysis: Two independent review authors extracted data from the selected papers. We calculated the risk ratio (RR), mean difference (MD), the number of people needed to treat for an additional beneficial outcome (NNTB), and the number of people needed to treat for an additional harmful outcome (NNTH), with 95% confidence intervals (CI) using Review Manager 5.

Main results: No new studies were identified for this update. We included four RCTs with 796 participants (70.5% women). Three RCTs compared the CHIVA method with vein stripping, and one RCT compared the CHIVA method with compression dressings in people with venous ulcers. We judged the quality of the evidence of the included studies as low to moderate due to imprecision caused by the low number of events and because the studies were open. The overall risk of bias across studies was high because neither participants nor outcome assessors were blinded to the interventions. The primary endpoint, clinical recurrence, pooled between studies over a follow-up of 3 to 10 years, showed more favorable results for the CHIVA method than for vein stripping (721 people; RR 0.63; 95% CI 0.51 to 0.78; I(2) = 0%, NNTB 6; 95% CI 4 to 10) or compression dressings (47 people; RR 0.23; 95% CI 0.06 to 0.96; NNTB 3; 95% CI 2 to 17). Only one study reported data on quality of life (presented graphically) and these results significantly favored the CHIVA method.The vein stripping group had a higher risk of side effects than the CHIVA group; specifically, the RR for bruising was 0.63 (95% CI 0.53 to 0.76; NNTH 4; 95% CI 3 to 6) and the RR for nerve damage was 0.05 (95% CI 0.01 to 0.38; I(2) = 0%; NNTH 12; 95% CI 9 to 20). There were no statistically significant differences between groups regarding the incidence of limb infection and superficial vein thrombosis.

Authors' conclusions: The CHIVA method reduces recurrence of varicose veins and produces fewer side effects than vein stripping. However, we based these conclusions on a small number of trials with a high risk of bias as the effects of surgery could not be concealed and the results were imprecise due to low number of events. New RCTs are needed to confirm these results and to compare CHIVA with approaches other than open surgery.

PubMed Disclaimer

Conflict of interest statement

SB: reports he received payment from Sanofi‐Aventis for presenting to an Internal expert class and from Otsuka/Ferrer for consultancy at EMA. These activities were not related to this review JME: none known JD: none known MJM: reports that Associazione "Umanizazione" della Chirurgia, Italy paid money to her institution to finance this review

Figures

1
1
Study flow diagram.
2
2
Risk of bias graph: review authors' judgements about each risk of bias item presented as percentages across all included studies.
3
3
Risk of bias summary: review authors' judgements about each risk of bias item for each included study.
4
4
Forest plot of comparison: 1 CHIVA versus stripping, outcome: 1.1 Recurrence of varicose veins.
5
5
Forest plot of comparison: 1 CHIVA versus stripping, outcome: 1.9 Side effects.
1.1
1.1. Analysis
Comparison 1 CHIVA versus stripping, Outcome 1 Recurrence of varicose veins.
1.2
1.2. Analysis
Comparison 1 CHIVA versus stripping, Outcome 2 Re‐treatment.
1.3
1.3. Analysis
Comparison 1 CHIVA versus stripping, Outcome 3 Free from reflux.
1.4
1.4. Analysis
Comparison 1 CHIVA versus stripping, Outcome 4 Esthetic improvement assessed by the participant.
1.5
1.5. Analysis
Comparison 1 CHIVA versus stripping, Outcome 5 Esthetic improvement assessed by the participant.
1.6
1.6. Analysis
Comparison 1 CHIVA versus stripping, Outcome 6 Esthetic improvement assessed by the investigator.
1.7
1.7. Analysis
Comparison 1 CHIVA versus stripping, Outcome 7 Cure or no clinical symptoms.
1.8
1.8. Analysis
Comparison 1 CHIVA versus stripping, Outcome 8 Clinical improvement.
1.9
1.9. Analysis
Comparison 1 CHIVA versus stripping, Outcome 9 Side effects.
1.10
1.10. Analysis
Comparison 1 CHIVA versus stripping, Outcome 10 Recurrence of varicose veins. Sensitivity analysis..
2.1
2.1. Analysis
Comparison 2 CHIVA versus compression dressing, Outcome 1 Recurrence of venous ulcer.
2.2
2.2. Analysis
Comparison 2 CHIVA versus compression dressing, Outcome 2 Cure of venous ulcer.
See this image and copyright information in PMC

Update of

References

References to studies included in this review

Carandina 2008 {published data only}
    1. Carandina S, Mari C, Palma M, Marcellino MG, Cisno C, Legnaro A, et al. Varicose vein stripping vs haemodynamic correction (CHIVA): a long term randomised trial. European Journal of Vascular and Endovascular Surgery 2008;35(2):230‐7. - PubMed
    1. Carandina S, Mari C, Palma M, Marcellino MG, Legnaro A, Liboni A, et al. Stripping vs haemodynamic correction (CHIVA): a long term randomised trial. Phlebology 2006;21(3):151. - PubMed
Iborra‐Ortega 2006 {published data only}
    1. Iborra E. Comparative clinical study: CHIVA vs phlebectomy [Ensayo clínico comparativo: Fleboextracción versus CHIVA]. Anales de Cirugía Cardíaca y Vascular 2006;12(2):109.
    1. Iborra E, Linares P, Hernández E, Vila R, Cairols MA. Clinical and random study comparing two surgical techniques for varicose veins treatment: immediate results [Estudio cínico y aleatorio que compara dos técnicas quirúrgicas para el tratamiento de las varices: resultados inmedatos]. Angiología 2000;6:253‐8.
    1. Iborra E, Vila R, Barjau E, Cairols MA. Surgical treatment of varicose veins: comparative study between two different techniques. Phlebology 2006;21(3):152.
    1. Iborra‐Ortega E, Barjau‐Urrea E, Vila‐Coll R, Ballon‐Carazas H, Cairols‐Castellote MA. Comparative study of two surgical techniques in the treatment of varicose veins of the lower extremities: results after five years of follow up [Estudio comparativo de dos técnicas quirúrgicas en el tratamiento de las varices de las extremidades inferiores: resultados tras cinco años de seguimiento]. Angiología 2006;58(6):459‐68.
Pares 2010 {published data only}
    1. Pares JO, Juan J, Tellez R, Mata A, Moreno C, Quer FX, et al. Varicose vein surgery: stripping versus the CHIVA method: a randomized controlled trial. Annals of Surgery 2010;251(4):624‐31. - PubMed
    1. Pares JO, Juan J, Tellez R, Mata A, Moreno C, Quer FX, et al. Varicose vein surgery: stripping versus the CHIVA method: a randomized controlled trial. Vasomed 2011;23(2):98. - PubMed
    1. Pares O, Juan J, Moreno C, Tellez R, Codony I, Mata A, et al. Randomized clinical trial on surgical techniques for the treatment of varicose veins in legs: non‐conservative treatment compared with a conservative one. Five years follow‐up. Phlebology 2008;23(5):243.
Zamboni 2003 {published data only}
    1. Zamboni P, Cisno C, Marchetti F, Mazza P, Fogato L, Carandina S, et al. Minimally invasive surgical management of primary venous ulcers vs. compression treatment: a randomized clinical trial. European Journal of Vascular and Endovascular Surgery 2003;25(4):313‐8. - PubMed

References to studies excluded from this review

Maeso 2001 {published data only}
    1. Maeso J, Juan J, Escribano J, Allegue NM, Matteo A, Gonzalez E, et al. Comparison of clinical outcome of stripping and CHIVA for treatment of varicose veins in the lower extremities. Annals of Vascular Surgery 2001;15(6):661‐5. - PubMed
Solis 2009 {published data only}
    1. Solís JV, Ribé L, Portero JL, Rio J. Stripping saphenectomy, CHIVA and laser ablation for the treatment of the saphenous vein insufficiency. Ambulatory Surgery 2009;15(1):11‐4.
Zamboni 1995 {published data only}
    1. Zamboni P, Marcellino MG, Feo CV, Pisano L, Vasquez G, Bertasi M, et al. Alternative saphenous vein sparing surgery for future grafting. Panminerva Medica 1995;37(4):190‐7. - PubMed
Zamboni 1996 {published data only}
    1. Zamboni P, Feo CV, Marcellino MG, Vasquez G, Mari C. Haemodynamic correction of varicose veins (CHIVA): an effective treatment?. Phlebology 1996;11(3):98‐101.
Zamboni 1998 {published data only}
    1. Zamboni P, Marcellino MG, Cappelli M, Feo CV, Bresadola V, Vasquez G, et al. Saphenous vein sparing surgery: principles, techniques and results. Journal of Cardiovascular Surgery 1998;39(2):151‐62. - PubMed

Additional references

Agus 2001
    1. Agus GB, Allegra C, Arpaia G, Botta G, Cataldi A, Gasbarro V, et al. Guidelines for the diagnosis and treatment of chronic venous insufficiency. International Angiology 2001;20(1):2‐37.
Allan 2000
    1. Allan PL, Bradbury AW, Evans CJ, Lee AJ, Vaughan Ruckley C, Fowkes FG. Patterns of reflux and severity of varicose veins in the general population ‐ Edinburgh Vein Study. European Journal of Vascular and Endovascular Surgery 2000;20(5):470‐7. - PubMed
Aziz 2011
    1. Aziz Z, Cullum NA, Flemming K. Electromagnetic therapy for treating venous leg ulcers. Cochrane Database of Systematic Reviews 2011, Issue 3. [DOI: 10.1002/14651858.CD002933.pub4] - DOI - PubMed
Blomgren 2004
    1. Blomgren L, Johansson G, Dahlberg‐Akerman A, Norén A, Brundin C, Nordström E, et al. Recurrent varicose veins: incidence, risk factors and groin anatomy. European Journal of Vascular and Endovascular Surgery 2004;27(3):269‐74. - PubMed
Carpentier 2004
    1. Carpentier PH, Maricq HR, Biro C, Ponçot‐Makinen CO, Franco A. Prevalence, risk factors, and clinical patterns of chronic venous disorders of lower limbs: a population‐based study in France. Journal of Vascular Surgery 2004;40(4):650‐9. - PubMed
Cavezzi 2007
    1. Cavezzi A, Labropoulos N, Partsch H, Ricci S, Caggiati A, Myers K, et al. Duplex ultrasound investigation of the veins in chronic venous disease of the lower limbs. UIP consensus document. Part II. Anatomy. Vasa 2007;36(1):62‐71. - PubMed
Chan 2011
    1. Chan CY, Chen TC, Hsieh YK, Huang JH. Retrospective comparison of clinical outcomes between endovenous laser and saphenous vein‐sparing surgery for treatment of varicose veins. World Journal of Surgery 2011;35(7):1679‐86. - PubMed
Coleridge‐Smith 2006
    1. Coleridge‐Smith P, Labropoulos N, Partsch H, Myers K, Nicolaides A, Cavezzi A. Duplex ultrasound investigation of the veins in chronic venous disease of the lower limbs. UIP consensus document. Part I. Basic principles. European Journal of Vascular and Endovascular Surgery 2006 ;31(1):83‐92. - PubMed
Cullum 2010
    1. Cullum NA, Al‐Kurdi D, Bell‐Syer SEM. Therapeutic ultrasound for venous leg ulcers. Cochrane Database of Systematic Reviews 2010, Issue 6. [DOI: 10.1002/14651858.CD001180.pub3] - DOI - PubMed
Escribano 2003
    1. Escribano JM, Juan J, Bofill R, Maeso J, Rodríguez‐Mori A, Matas M. Durability of reflux‐elimination by a minimal invasive CHIVA procedure on patients with varicose veins. A 3‐year prospective case study. European Journal of Vascular and Endovascular Surgery 2003;25(2):159‐63. - PubMed
Flemming 1999
    1. Flemming K, Cullum NA. Laser therapy for venous leg ulcers. Cochrane Database of Systematic Reviews 1999, Issue 1. [DOI: 10.1002/14651858.CD001182] - DOI - PubMed
Franceschi 1988
    1. Franceschi C. Theorie et pratique de la cure: conservatrice et hemodynamique de l'insuffisance veineuse en ambulatoire. Precy‐sous‐Thil, France: Editions de l’Armançon, 1988.
Franceschi 1997
    1. Franceschi C. Measures and interpretation of venous flow in stress tests. Manual compression and Parana manoeuver. Dynamic reflux index and Psatakis index [Mesures et interprétation des flux veineux lors des manoevres de stimulation. Compressions manuelles et manoeuvre de Paranà. Indice dynamique de reflux (IDR) et indice de Psatakis]. Journal des Maladies Vasculaires 1997;22(2):96‐136. - PubMed
Goren 1996
    1. Goren G, Yellin AE. Hemodynamic principles of varicose vein therapy. Dermatologic Surgery 1996;22(7):657‐62. - PubMed
GRADE 2004
    1. GRADE Working Group. Grading quality of evidence and strength of recommendations. BMJ 2004;328:1490‐4. - PMC - PubMed
Hamdan 2012
    1. Hamdan A. Management of varicose veins and venous insufficiency. JAMA 2012;308(24):2612‐21. - PubMed
Higgins 2011
    1. Higgins JPT, Green S (editors). Cochrane Handbook for Systematic Reviews of Interventions Version 5.1.0 [updated March 2011]. The Cochrane Collaboration, 2011. Available from www.cochrane‐handbook.org.
Hobbs 1974
    1. Hobbs JT. Surgery and sclerotherapy in the treatment of varicose veins. A random trial. Archives of Surgery 1974;109:793‐6. - PubMed
Juan 2002
    1. Juan J, Escribano JM, Maeso J. Hemodynamic after stripping of varicose vein [Hämodynamik des Varizenrezidivs nach Strippingoperation]. 18 Jahreskongress 2002 der Deutschen Gessellschaft für GefäBchirurgie ‐ Gesellschaft für vaskuläre und endovaskuläre Chirurgie. Würzburg (Germany). 2002.
Jull 2008
    1. Jull AB, Rodgers A, Walker N. Honey as a topical treatment for wounds. Cochrane Database of Systematic Reviews 2008, Issue 4. [DOI: 10.1002/14651858.CD005083.pub2] - DOI - PubMed
Keller 1905
    1. Keller WL. A new method of extirpating the internal saphenous and similar veins in varicose conditions. A preliminary report. New York Medical Journal 1905;82:385‐6.
Kranke 2004
    1. Kranke P, Bennett MH, Debus SE, Roeckl‐Wiedmann I, Schnabel A. Hyperbaric oxygen therapy for chronic wounds. Cochrane Database of Systematic Reviews 2004, Issue 1. [DOI: 10.1002/14651858.CD004123.pub2] - DOI - PubMed
Kurz 1999
    1. Kurz X, Kahn SR, Abenhaim L, Clement D, Norgren L, Baccaglini U, et al. Chronic venous disorders of the leg: epidemiology, outcomes, diagnosis and management. Summary of an evidence‐based report of the VEINES task force. Venous Insufficiency Epidemiologic and Economic Studies. International Angiology 1999;18(2):83‐102. - PubMed
Labropoulos 2001
    1. Labropoulos N, Tiongson J, Pryor L, Tassiopoulos AK, Kang SS, Mansour MA, et al. Nonsaphenous superficial vein reflux. Journal of Vascular Surgery 2001;34(5):872‐7. - PubMed
Labropoulos 2005
    1. Labropoulos N, León L, Kwon S, Tassiopoulos A, González‐Fajardo JA, Kang SS, et al. Study of the venous reflux progression. Journal of Vascular Surgery 2005;41(2):291‐5. - PubMed
Lee 2003
    1. Lee AJ, Evans CJ, Allan PL, Ruckley CV, Fowkes FG. Lifestyle factors and the risk of varicose veins: Edinburgh Vein Study. Journal of Clinical Epidemiology 2003;56(2):171‐9. - PubMed
Lofgren 1977
    1. Lofgren EP. The operative treatment of varicose veins. In: Rutherford RB editor(s). Vascular Surgery. Philadelphia: WB Saunders, 1977:1169‐75.
Martinez‐Zapata 2005
    1. Martinez‐Zapata MJ, Bonfill Cosp X, Moreno RM, Vargas E, Capellà D. Phlebotonics for venous insufficiency. Cochrane Database of Systematic Reviews 2005, Issue 3. [DOI: 10.1002/14651858.CD003229.pub2] - DOI - PubMed
Mendoza 2008
    1. Mendoza E. CHIVA 1988‐2008: review of studies on the CHIVA method and its development in different countries. Gefasschirurgie 2008;13(4):249‐56.
Mendoza 2011
    1. Mendoza E, Berger V, Zollmann C, Bomhoff M, Amsler F. Diameter‐reduction of the great saphenous vein and common femoral vein after CHIVA [Kaliberreduktion der V saphena magna und der V femoralis communis nach CHIVA]. Phlebologie 2011;40(2):73‐8.
Milone 2011
    1. Milone M, Salvatore G, Maietta P, Sosa Fernandez LM, Milone F. Recurrent varicose veins of the lower limbs after surgery. Role of surgical technique (stripping vs. CHIVA) and surgeon's experience. Il Giornale di Chirurgia 2011;32(11‐12):460‐3. - PubMed
Mowatt‐Larssen 2012
    1. Mowatt‐Larssen E, Shortell CK. Treatment of primary varicose veins has changed with the Introduction of new techniques. Seminars in Vascular Surgery 2012;25(1):18‐24. - PubMed
Muller 1966
    1. Muller R. Treatment of varicose veins by ambulatory phlebectomy [Traitement des varices par phlébectomie ambulatoire]. Phlebologie 1966;19(4):277‐9. - PubMed
Nelson 2000
    1. Nelson EA, Bell‐Syer SEM, Cullum NA, Webster J. Compression for preventing recurrence of venous ulcers. Cochrane Database of Systematic Reviews 2000, Issue 4. [DOI: 10.1002/14651858.CD002303] - DOI - PubMed
Nelson 2011
    1. Nelson EA, Mani R, Thomas K, Vowden K. Intermittent pneumatic compression for treating venous leg ulcers. Cochrane Database of Systematic Reviews 2011, Issue 2. [DOI: 10.1002/14651858.CD001899.pub3] - DOI - PubMed
Nesbitt 2011
    1. Nesbitt C, Eifell RK, Coyne P, Badri H, Bhattacharya V, Stansby G. Endovenous ablation (radiofrequency and laser) and foam sclerotherapy versus conventional surgery for great saphenous vein varices. Cochrane Database of Systematic Reviews 2011, Issue 10. [DOI: 10.1002/14651858.CD005624.pub2] - DOI - PubMed
Nicolaides 2000
    1. Nicolaides AN, Cardiovascular Disease Educational and Research Trust, European Society of Vascular Surgery, The International Angiology Scientific Activity Congress Organization, International Union of Angiology, Union Internationale de Phlebologie at the Abbaye des Vaux de Cernay. Investigation of chronic venous insufficiency. A consensus statement. Circulation 2000;102(20):E126‐63. - PubMed
O'Meara 2009
    1. O'Meara S, Cullum NA, Nelson EA. Compression for venous leg ulcers. Cochrane Database of Systematic Reviews 2009, Issue 1. [DOI: 10.1002/14651858.CD000265.pub2] - DOI - PubMed
O'Meara 2010
    1. O'Meara S, Al‐Kurdi D, Ologun Y, Ovington LG. Antibiotics and antiseptics for venous leg ulcers. Cochrane Database of Systematic Reviews 2010, Issue 1. [DOI: 10.1002/14651858.CD003557.pub3] - DOI - PubMed
Palfreyman 2006
    1. Palfreyman SSJ, Nelson EA, Lochiel R, Michaels JA. Dressings for healing venous leg ulcers. Cochrane Database of Systematic Reviews 2006, Issue 3. [DOI: 10.1002/14651858.CD001103.pub2] - DOI - PubMed
Perrin 2000
    1. Perrin MR, Guex JJ, Ruckley CV, Palma RG, Royle JP, Eklof B, et al. Recurrent varices after surgery (REVAS), a consensus document. REVAS Group. Cardiovascular Surgery 2000;8(4):233‐45. - PubMed
Porter 1995
    1. Porter JM, Moneta GL. Reporting standards in venous disease: an update. International Consensus Committee on Chronic Venous Disease. Journal of Vascular Surgery 1995;21(4):635‐45. - PubMed
RevMan 2011 [Computer program]
    1. The Nordic Cochrane Centre, The Cochrane Collaboration. Review Manager (RevMan). Version 5.1. Copenhagen: The Nordic Cochrane Centre, The Cochrane Collaboration, 2011.
Rigby 2004
    1. Rigby KA, Palfreyman SSJ, Beverley C, Michaels JA. Surgery versus sclerotherapy for the treatment of varicose veins. Cochrane Database of Systematic Reviews 2004, Issue 4. [DOI: 10.1002/14651858.CD004980] - DOI - PMC - PubMed
Sterne 2011
    1. Sterne JAC, Egger M, Moher D (Editors). Chapter 10: Addressing reporting bias. In: Higgins JPT, Green S (editors). Cochrane Handbook for Systematic Reviews of Interventions Version 5.1.0 [updated March 2011]. The Cochrane Collaboration, 2011. Available from www.cochrane‐handbook.org.
Tisi 2006
    1. Tisi PV, Beverley C, Rees A. Injection sclerotherapy for varicose veins. Cochrane Database of Systematic Reviews 2006, Issue 4. [DOI: 10.1002/14651858.CD001732.pub2] - DOI - PubMed
Vanhouette 1997
    1. Vanhoutte PM, Corcaud S, Montrion C. Venous disease: from pathophysiology to quality of life. Angiology 1997;48(7):559‐67. - PubMed
Winterborn 2004
    1. Winterborn RJ, Foy C, Earnshaw JJ. Causes of varicose vein recurrence: late results of a randomized controlled trial of stripping the long saphenous vein. Journal of Vascular Surgery 2004;40(4):634‐9. - PubMed

References to other published versions of this review

Bellmunt‐Montoya 2012
    1. Bellmunt‐Montoya S, Escribano JM, Dilme J, Martinez‐Zapata MJ. CHIVA method for the treatment of varicose veins. Cochrane Database of Systematic Reviews 2012, Issue 2. [DOI: 10.1002/14651858.CD009648] - DOI
Bellmunt‐Montoya 2013
    1. Bellmunt‐Montoya S, Escribano JM, Dilme J, Martinez‐Zapata MJ. CHIVA method for the treatment of chronic venous insufficiency. Cochrane Database of Systematic Reviews 2013, Issue 7. [DOI: 10.1002/14651858.CD009648.pub2] - DOI - PubMed

Publication types