2025. gadā aizstāvētie promocijas darbi un kopsavilkumi

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Browsing 2025. gadā aizstāvētie promocijas darbi un kopsavilkumi by Author "Mamaja, Biruta"

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    Thromboelastometry for Microvascular Flap Thrombosis Risk Assessment in Trauma Patients Undergoing Reconstructive Surgery. Doctoral Thesis
    (Rīga Stradiņš University, 2025) Stepanovs, Jevgeņijs; Vanags, Indulis; Mamaja, Biruta
    Despite technical progress, microvascular flap thrombosis remains a concern in reconstructive surgery. Although microvascular thrombosis is most commonly secondary to technical mishaps and/or prolonged surgical time, a number of other preoperatively identifiable factors have a potential impact on anastomotic thrombosis rate and outcome of tissue transfer. In trauma patients, diagnosing a condition of posttraumatic hypercoagulability is complex. In recent years, viscoelastic methods, including rotational thromboelastometry (RTE) have been widely used for monitoring coagulant activity, but there is a scarcity of data on its use for predicting the risks of microvascular flap thrombotic complications. The aim of the present study was to evaluate the predictive capacity of rotational thromboelastometry for early risk assessment of microvascular flap thrombosis in trauma patients undergoing reconstructive surgery with particular interest in the time period passed from trauma to reconstruction, dividing patients into two subgroups – early surgery and late surgery. During the study, demographic data, type of surgery and surgical parameters were recorded for each patient. Preoperatively, a blood sample was taken to perform RTE and standard coagulation tests. We evaluated the major risk factors for microvascular flap thrombosis in the total population studied and compared the major risk factors for microvascular flap thrombosis in subgroups of early versus late surgery. The results showed that thrombogenic co-morbidities, prolonged surgical time, hyperfibrinogenaemia and hypercoagulability in RTE may lead to a higher rate of postoperative microvascular thrombosis, although the risk factors for free flap thrombosis differ between early and late surgery patients. RTE data can be a convenient tool for detecting hypercoagulability, although its prognostic value varies depending on the time elapsed after trauma. Hypercoagulability detected by RTE may increase the probability of microvascular flap thrombosis, especially in patients undergoing elective surgery (late surgery subgroup) – later than 30 days after a traumatic injury. The presence of thrombogenic co-morbidities, often associated with hypercoagulability, also increases the risk of flap thrombosis in the late post-trauma period. In contrast, in the early surgery subgroup, the duration of microvascular surgery seemed to play a more important role in estimating the risk of microvascular flap thrombosis during the first 30 days after a traumatic injury. We recommend that each patient scheduled for microvascular free flap surgery should be evaluated in a timely manner, with special attention to data on the time elapsed after the traumatic event, the patient’s medical history and preoperative coagulation tests, thus providing more careful preoperative assessment and individualised recommendations for anaesthesiologic and surgical management.
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    Thromboelastometry for Microvascular Flap Thrombosis Risk Assessment in Trauma Patients Undergoing Reconstructive Surgery. Summary of the Doctoral Thesis
    (Rīga Stradiņš University, 2025) Stepanovs, Jevgeņijs; Vanags, Indulis; Mamaja, Biruta
    Despite technical progress, microvascular flap thrombosis remains a concern in reconstructive surgery. Although microvascular thrombosis is most commonly secondary to technical mishaps and/or prolonged surgical time, a number of other preoperatively identifiable factors have a potential impact on anastomotic thrombosis rate and outcome of tissue transfer. In trauma patients, diagnosing a condition of posttraumatic hypercoagulability is complex. In recent years, viscoelastic methods, including rotational thromboelastometry (RTE) have been widely used for monitoring coagulant activity, but there is a scarcity of data on its use for predicting the risks of microvascular flap thrombotic complications. The aim of the present study was to evaluate the predictive capacity of rotational thromboelastometry for early risk assessment of microvascular flap thrombosis in trauma patients undergoing reconstructive surgery with particular interest in the time period passed from trauma to reconstruction, dividing patients into two subgroups – early surgery and late surgery. During the study, demographic data, type of surgery and surgical parameters were recorded for each patient. Preoperatively, a blood sample was taken to perform RTE and standard coagulation tests. We evaluated the major risk factors for microvascular flap thrombosis in the total population studied and compared the major risk factors for microvascular flap thrombosis in subgroups of early versus late surgery. The results showed that thrombogenic co-morbidities, prolonged surgical time, hyperfibrinogenaemia and hypercoagulability in RTE may lead to a higher rate of postoperative microvascular thrombosis, although the risk factors for free flap thrombosis differ between early and late surgery patients. RTE data can be a convenient tool for detecting hypercoagulability, although its prognostic value varies depending on the time elapsed after trauma. Hypercoagulability detected by RTE may increase the probability of microvascular flap thrombosis, especially in patients undergoing elective surgery (late surgery subgroup) – later than 30 days after a traumatic injury. The presence of thrombogenic co-morbidities, often associated with hypercoagulability, also increases the risk of flap thrombosis in the late post-trauma period. In contrast, in the early surgery subgroup, the duration of microvascular surgery seemed to play a more important role in estimating the risk of microvascular flap thrombosis during the first 30 days after a traumatic injury. We recommend that each patient scheduled for microvascular free flap surgery should be evaluated in a timely manner, with special attention to data on the time elapsed after the traumatic event, the patient’s medical history and preoperative coagulation tests, thus providing more careful preoperative assessment and individualised recommendations for anaesthesiologic and surgical management.
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    Tromboelastometrija mikrovaskulāro lēveru kājiņas trombozes riska novērtēšanā traumu pacientiem, kuriem tiek veikta ķirurģiska rekonstrukcija. Promocijas darba kopsavilkums
    (Rīgas Stradiņa universitāte, 2025) Stepanovs, Jevgeņijs; Vanags, Indulis; Mamaja, Biruta
    Neņemot vērā attīstību tehniskajā aspektā, mikrovaskulāro lēveru kājiņas tromboze tāpat rada nozīmīgu risku. Lai gan biežāk tieši ķirurģiskas problēmas veicina lēveru kājiņas trombozi, vairākiem preoperatīvi identificējamiem faktoriem ir potenciāls ietekmēt lēveru kājiņas trombožu biežumu un transpozīcijas iznākumu. Traumas izraisītas hiperkoagulācijas diagnostika ir sarežģīta. Pēdējos gados viskoelastiskās metodes, tā skaitā rotācijas tromboelastometrija (RTE), tiek daudz izmantotas koagulācijas sistēmas aktivitātes monitorēšanai, diemžēl nav daudz pētījumu, kuros apskatīta viskoelastisko testu spēja paredzēt mikrovaskulāro lēveru kājiņas trombozi. Mūsu darba mērķis bija izvērtēt RTE spēju agrīni prognozēt mikrovaskulāro lēveru kājiņas trombozes risku pacientiem ar traumām, kuriem tiek veikta ķirurģiska rekonstrukcija, ar īpašu interesi par laika periodu, kas pagājis no traumas līdz rekonstrukcijai, sadalot pacientus divās apakšgrupās – agrīnās ķirurģijas un vēlīnās ķirurģijas. Pētījuma laikā tika ievākti katra pacienta dati par operācijas veidu, ķirurģiskajiem parametriem un demogrāfiskajiem rādītājiem. Pirms operācijas tika iegūts asins paraugs RTE un standarta koagulācijas testiem. Mēs izvērtējām galvenos mikrovaskulāro lēveru trombozes riska faktorus visā pētītajā populācijā un salīdzinājām galvenos mikrovaskulāro lēveru trombozes riska faktorus agrīnās un vēlīnās ķirurģijas apakšgrupās. Mūsu rezultāti parādīja, ka trombogēnas blakusslimības, ilgs operācijas laiks, hiperfibrinogenēmija standarta asins analīzēs un hiperkoagulācija RTE testos var novest pie augstākas pēcoperācijas mikrovaskulāro lēveru kājiņas trombozes incidences, lai gan riska faktori lēveru kājiņas trombozei var atšķirties starp agrīnās un vēlīnās ķirurģijas pacientiem. Mēs parādījām, ka RTE datu novērtējums var būt ērts līdzeklis hiperkoagulācijas noteikšanai, lai gan tā prognostiskā vērtība mainās atkarībā no pagājušā pēctraumas laika perioda. RTE konstatētā hiperkoagulācija var palielināt mikrovaskulāro lēveru trombozes iespējamību, īpaši pacientiem, kuriem tiek veikta plānveida operācija (vēlīnās ķirurģijas apakšgrupa), vēlāk nekā 30 dienas pēc traumas. Pavadošās patoloģijas, saistītas ar paaugstināto tendenci uz trombu veidošanos, arī palielina lēveru trombozes risku. Pretstatā agrīnās ķirurģijas apakšgrupā pirmo 30 dienu periodā pēc traumas svarīgāka loma mikrovaskulāro lēveru trombozes riska noteikšanā bija tieši mikrovaskulāras operācijas ilgumam. Mēs rekomendējam laikus izvērtēt katru pacientu, kuram ieplānota mikrovaskulāra brīva lēvera ķirurģija, īpašu uzmanību pievēršot datiem par laiku, kas pagājis pēc traumatiskā notikuma, pacienta slimības vēsturei un pirmsoperācijas koagulācijas testu rezultātiem, tādējādi nodrošinot rūpīgāku pirmsoperācijas izvērtēšanu un individuālus ieteikumus anestezioloģiskai un ķirurģiskai taktikai.