Perioperative Predictors of Unfavorable Outcome of Vascular Surgery

6 w w w . r e a n i m a t o l o g y . c o m Сопутствующая сердечная недостаточность является общепризнанным фактором риска у хирургичес& ких пациентов в кардиальной, так и в некардиальной хирургии. Цель работы состояла в поиске и выделении факторов или маркеров, позволяющих прогнозировать ранний (до 30 дней) и поздний (до 1 года) неблагоприятный исход у пациентов с острой сердечной недоста& точностью (ОСН) в сосудистой хирургии. Материалы и методы. Провели рандомизированное, мультицентровое, ретроспективно — проспектив& ное исследование, рандомизировали 89 пациентов, подписавших информированное согласие. На 4&х эта& пах проводимого исследования фиксировали значения сердечного индекса (СИ), фракцию изгнания лево& го желудочка (ФИлж), брали пробу крови для определения содержания NT&proBNP. Содержание Тропанина Т (TnT) определяли только на 3&ем этапе исследования. Фиксировали необходимое время пре& бывания в палате отделения анестезиологии&реаниматологии (ПИТ) и в стационаре, частоту развития ин& фарктов и инсультов в ранние (до 30 суток) сроки после перенесенной операции, 30&ти дневную и годовую летальность. Результаты. Предикторы неблагоприятных событий изучали в смешанной группе больных, для кото& рых использовали различные методы профилактики ОСН в периоперационном периоде. Частота развития острого инфаркта миокарда (ОИМ) составила 12%; инсульта 2%. Госпитальная летальность составила 2%; годовая летальность — 10%. Пациенты провели в палате интенсивной терапии 3 (2—4) дня; время пребы& вания в стационаре составило 11 (10—13) дней, неблагоприятный композитный исход оперативного лече& ния отметили у 15% пациентов. Единственным значимым предиктором оказалось содержание тропонина Т в 1&е сутки постопрерационного периода. При изучении прогностической значимости различных пока& зателей годовой летальности получили сходный результат. Для прогнозирования возможных сроков лече& ния наиболее значимым критерием оказался Vasoactive Inotropes Score (VIS). Заключение. Подтвердили прогностическую значимость определения ТнТ в ранние сроки после выпол& нения реконструктивных сосудистых операций у пациентов со сниженной фракцией изгнания левого желу& дочка. Диагностическая ценность расчета VIS требует дальнейшего подтверждения.

The aim of this study was to search for and identify factors or markers, which would permit to predict early (up to 30 days) or late (up to 1 year) adverse outcomes in patients with acute heart failure (AHF) in the vascular surgery.
As for other surgery related risks for patients with heart failure (HF), the anesthesiologist fre quently is not so well aware of them.At any rate, diagnosis and prevention of AHF receive consider ably less attention than prevention and treatment of perioperative myocardial infarction.
In the meantime, the perioperative mortality rate in non cardiac surgery of patients with AHF is 2-4 times as high as in patients with CAD [6][7][8].Concomitant AHF cannot be ignored also due to the incidence of this state: it comprises 8% to 15% of cases among in patients over 65 years [9].Since the age of surgical patients becomes more advanced, this problem cannot be called rare or insignificant [7].
In this connection, the search for adverse event markers in the selected population of patients becomes particularly significant.
The aim of this study was to search for and identify factors or markers, which would permit to predict early (up to 30 days) or late (up to 1 year) adverse outcomes in AHF patients in the vascular surgery.

Materials and Methods
A prospective -retrospective, multicenter, random ized control study was carried out.
2. Age: >45 years old and<75 years old; 3. Left ventricular ejection fraction <50%; Materials and Methods.A randomized, multicenter, prospective -retrospective study was performed.89 patients who had signed the Informed Consent Form were randomized.Throughout the four stages of the study, the cardiac index (CI) and the left ventricle ejection fraction (LVEF) values were recorded.At the same stages, blood was sampled to be tested for the NT proBNP level.The TnT level was tested only at the 3rd stage of the study.The required stay in the intensive care unit (ICU) and in the in patient hospital, the incidence of infarctions and strokes during the early postoperative period (up to 30 days), the 30 day and one year mortality rates were recorded.
Results.Different AHF prevention methods were used in patients included into this study in the postopera tive period.Predictors of adverse events were studied in a combined population.
The incidence of acute myocardial infarction (AMI) was 12% and that of stroke was 2%.
The in hospital mortality rate in the combined group was 2%; the one year mortality was 10%.Patients stayed in the intensive care unit for 3 (2-4) days; the hospital stay was 11 (10-13) days; the composite adverse outcome of the surgical treatment was registered in 15% of patients.As a result, the Troponin T level was the only signifi cant prognostic factor during the first 24 hours of the postoperative period.A study of the prognostic significance of different parameters in relation to their effect on the one year mortality rate demonstrated a similar result.Vasoactive Inotropes Score (VIS) turned out to be the most significant criterion for prediction of possible treat ment duration.
Conclusion.The study results confirmed the predictive value of early determination of TnT levels after repar ative vascular surgeries in patients with decreased left ventricular ejection fraction.The diagnostic value of the VIS calculation needs further confirmation.w w w .r e a n i m a t o l o g y .c o m Within the specified period of time, there were 125 patients eligible for the study.However, later on, 89 patients who signed the informed consent were random ized in the study.
General characteristics of patients in the compared groups are presented in Table 1.
A detailed description of anesthesia methods and study parameters is presented in the article we published earlier [10].
All patients underwent surgeries in the infrarenal part of aorta (aortofemoral bypass surgery or grafting) for life saving indications because of critical ischemia of the lower extremities and the risk of amputation.A low left ventricle ejection fraction was common for all patients.All patients treated with aspirin and beta blockers before the surgery continued administration of the drugs till the day of the surgery and resumed, when oral intake of fluids was allowed again.
There were four test stages identified: 1. 24 hours before the surgery.2. After induction of anesthesia prior to the surgery; 3. 2-4 hours after the surgery; 4. 26-30 hours after the surgery.At each stage, CI and LVEF values were recorded.At the same stages, blood samples were harvested to test the NT proBNP level.The TnT level was determined only at the 3rd stage of the study.
The required stay in the intensive care unit (ICU) and in patient hospital, the incidence of infarctions and strokes in the early postoperative period (up to 30 days), the 30 day and one year mortality rates were recorded.
The vasoactive inotropes score (VIS) was deter mined as the maximum sympathomimetic infusion rate
Logistic regression coefficients of potential predictors of an adverse composite outcome (NT proBNP (baseline outcome difference), cardiac index (baseline outcome dif ference), and LV ejection fraction (baseline outcome dif ference)) were calculated as a difference between the second stage and outcome stage data.
Quantitative parameters were analyzed for normal ity of distribution using Lilliefors and Shapiro Wilk tests.The t test was used for comparison of normally distributed quantitative parameters.Abnormally dis tributed findings were compared using the Whitney Mann U test.The χ 2 (chi square) test and Fisher's exact test were used for comparison of qualitative data.Friedman test with a posteriori analysis using the Wilcoxon rank sum test with Bonferroni's correctio was used to analyze the dynamics of abnormally distributed data.
Mean values of normally distributed quantitative para meters are represented by an arithmetical mean with a stan dard deviations, while those of not normal distributed -by a median with an interquartile interval.
The results were considered statistically significant at the level of Р<0.05.

Results and Discussion
Different AHF prevention methods were used in patients included into this study in the postopera tive period [10].However, we studied predictors of adverse events in a combined population.
The incidence of AMI was 12% and that of stroke was 2%.
The hospital (30 day) mortality in the mixed group was 2%; the one year mortality was 10%.Patients stayed in intensive therapy unit for 3 (2-4) days; the hospital stay was 11 (10-13) days; an adverse composite outcome of the surgical treatment was registered in 15% of patients.
There was an effort made to detect the most significant predictor of the adverse composite out come in the tested patient population (Table 2).
As a result, Troponin T level within the first 24 hours of the postoperative period turned out to be the only predictor with a statistically significant regression coefficient.It seems all the more sur prising that the comparison was performed with such important AHF diagnostic tests as CI, LVEF and NT proBNP.It appears that the risk of adverse outcomes after vascular surgeries performed on AHF patients is more likely related to the develop ment of a peri operative infarction than to AHF decompensation.
regarding their effect on the one year mortality (Table 2).
Our data prove the high predictive value of early Troponin tests in patients with concurrent heart failure [9,11].
However, VIS proved to be the most significant criterion for prediction of potential treatment dura tion (Table 2).
To explain this fact, one should recall that the physiological significance of VIS is the total dose of cardiotonics and vasoconstrictors used in the thera py of AHF and circulatory insufficiency.It is evident that the cardiovascular inefficiency is the most severe situation for an anesthesiologist, which demands intense and long term treatment.Therefore, the predictive value of the considered parameter is quite understandable.Incidentally, regarding the prediction of the composite outcome and the one year mortality, the parameter considered here comes second in significance (although statisti cally insignificant) following the TnT.One cannot exclude that in the case of a more profound study we would get a significant result here, as well.

Заключение
В результате проведенного исследования еще раз подтверждена прогностическая значи TnT again was the only predictor of the one year mortality with a statistically significant result (Table 2).
The result of performed study has again confirmed the predictive value of early determination of TnT after reparative vascular surgeries in patients with decreased left ventricular ejection fraction.The diagnostic value of VIS calculation still needs further studies.мость определения ТнТ в ранние сроки после вы полнения реконструктивных сосудистых опера ций у пациентов со сниженной ФИлж.

Table 1 . General patients' characteristics.
Prediction of Outcome in Critical StatesThe data are presented in the form of a mean value ± standard deviation or median [interquartile interval].
Note.w w w .r e a n i m a t o l o g y .c o m