Kratkotrajna potpora cirkulaciji i izmjeni plinova u krvi

Heart failure continues to be an ever-growing public health concern. The continued aging of the population has contributed to the increasing incidence and prevalence of heart failure. Mechanical circulatory support is used to treat patients with advanced heart failure. A mechanical pump is surgically implanted to provide pulsatile or non-pulsatile flow of blood to supplement or replace the blood flow generated by the native heart. The main purpose of a mechanical circulatory support is to unload the failing heart and help maintain forward cardiac output and vital organ perfusion. A big variety of devices exists: from the percutaneous and short-term support, which can be used in the operating room or the cath-lab and afterwards in the intensive or coronary care units, to the internal and long-term devices, which can be used as a bridge-to-recovery or cardiac transplant, or as definitive therapy in patients with contraindication to cardiac transplant. This treatment involves not only the cardiac surgeons, but also the cardiologists, anaesthesiologists, intensivists and perfusionists. Appropriate patient selection represents the critical determinant of successful outcomes with the VAD therapy. The predictive risk stratification is extremely important for achieving the minimal peri-operative mortality rate. As VAD technology progresses, the collaboration of multidisciplinary teams composed of engineers, scientists, physicians, and nurses will continue to refine the technology and improve patient care and operation outcomes. Advances in device design will allow for an easier implantation and create smaller, more efficient, durable, and reliable units.Zatajenje srca s porastom incidencije i prevalencije u sve starijoj populaciji polako postaje javno zdravstveni problem. Mehanička cirkulacijska potpora se koristi kao oblik liječenja u skupini bolesnika s uznapredovalim zatajenjem srca. Mehanička crpka se kirurški implantira kako bi osigurala, bilo pulsatilni, bilo nepulsatilni protok krvi koji služi kao supplement ili kao zamjena protoku krvi kojeg bi trebalo generirati srce. Glavni cilj i namjena mehaničke cirkulacijske potpore je volumno rasteretiti srce u terminalnom zatajenju i pomoći u održavanju protoka vitalnih organa održavajući minutni volumen. Prisutna je široka paleta uređaja: od onih koji se mogu perkutano implantirati, uređaja za kratkoročnu potporu koji se mogu koristiti u operacijskoj sali, u laboratoriju za kateterizaciju kao i u jedinici intenzivnog liječenja do potpuno implantibilnih uređaja za dugoročnu potporu. Uređaji mogu biti korišteni kao terapija premoštenja do oporavka ili do transplantacije srca ili, u pojedinim slučajevima, uređaji predstavljaju definitivnu terapiju, npr. kod bolesnika u kojih je kontraindicirana transplantacija. Ovaj oblik liječenja ne uključuje samo kardiokirurge, već i kardiologe, anesteziologe kao i perfuzioniste. Pravilna trijaža bolesnika predstavlja ključnu točku uspjeha u ishodu liječenja volesnika s mehaničkom cirkulacijskom potporom. Prijeoperacijska stratifikacija rizika je iznimno važna u minimaliziranju stope perioperacijsakog mortaliteta. Istovremeni tehnološki razvoj, kao i multidisciplinarna suradnja konstruktora uređaja, znanstvenika, liječnika i ostalog medicinskog osoblja dovest će do unaprijeđenja cjelokupnog procesa liječenja ove skupine bolesnika. Daljnji tehnološki razvoj ide u smjeru pojednostavljenja procesa implantacije, s manjim, efikasnijim, trajnijim i još više pouzdanijim uređajima

Off-pump coronary bypass surgery adversely affects alveolar gas exchange

While the introduction of off-pump myocardial revascularization (OPCAB) has initially shown promise in reducing respiratory complications inherent to conventional coronary surgery, it has failed to eradicate them. Our study focused on quantifying the lactate release from the lungs and the dysfunction at the level of the alveolar-capillary membrane precipitated by OPCAB at different time points after the insult. Furthermore, we aimed to determine the impact of pulmonary lactate production on systemic lactic acid concentrations. The study was conducted in a prospective observational fashion. Forty consecutive patients undergoing OPCAB were analyzed. The mean patient age was 60 +/- 10 years. The mean EUROScore was 3.8 +/- 2.9. The alveolar-arterial O2 gradient increased from 19 [range 9 to 30] to 26 [range 20 to 34] kPa (P < 0.001) and remained elevated up to 6 hours after surgery. It rapidly declined again by 18 hours postoperatively. The observed increase in the pulmonary lactate release (PLR) from a baseline value of 0.022 [range -0.074 to 0.066] to 0.089 [range 0.016 to 0.209] mmol/min/m2 at six hours postoperatively did not reach statistical significance (P = 0.105). The systemic arterial lactate (Ls) concentration increased from 0.94 [range 0.78 to 1.06] to 1.39 [range 0.97 to 2.81] mmol/L (P < 0.001). The venoarterial pCO2 difference showed no significant change in comparison to baseline values. The mortality in the studied group was 2.5% (1/40). The pulmonary lactate production showed a statistically significant correlation with the systemic lactate concentration (R = 0.46; P = 0.003). Pulmonary injury following off pump myocardial revascularization was evidenced by a prompt increase in the alveolar-arterial oxygen gradient. The alveolar-arterial O2 gradient correlated with the duration of mechanical ventilation

Rezultati ugradnje Levitronix Centrimag mehaničke potpore srcu u Kliničkom bolničkom centru Zagreb

Background: The management of end stage heart failure has been revolutionized by the use of mechanical circulatory support. The Levitronix Centrimag ventricular assist device (VAD) is designed for short-term cardiac assistance as a bridge to a more permanent solution to the hemodynamic problem. It has been used as bridge-to-transplantation, bridge-to-bridge, bridge-to-recovery, and bridge-to-decision. Methods: In the period between September 2008 and November 2009, six patients received mechanical cardiac assistance with the Levitronix Centrimag device at our institution. In one patient, the indication was postcardiotomy cardiogenic shock. In the remaining five patients, the device was implanted electively, due to progressive decompensation of chronic heart failure unresponsive to medical therapy. Results: The patient having received a biventricular assist device (BIVAD) in the postcardiotomy setting was 65 years of age. His ejection fraction and EuroSCORE were 20 % and 25, respectively. His NT-pro-BNP was 9,428 pg/ml and his pre-implantation lactate was 8.8 mmol/L. The mean age in the group of patients, in whom the VAD was placed due to decompensated severe heart failure (DSHF ), was 46 ± 11 years. Their ejection fraction and logistic EuroSCORE were 16 ± 2 % and 28 ± 7, respectively. The preoperative serum lactate and NT-pro-BNP concentrations were 1.7±0.8 mmol/L and 9577 ± 3674 pg/ml, respectively. Of these, three patients had evidence of end organ dysfunction. The low cardiac output was responsible for acute renal failure, requiring renal replacement therapy in one patient. Neurocognitive dysfunction and renal failure not requiring dialysis was seen in another. The third patient had long standing primary hepatic insufficiency. A reversal of end organ dysfunction was seen in the former two patients, whereas the hepatic insufficiency was not caused by hemodynamic compromise and was, therefore, not relieved by circulatory support. The single patient, who had suffered from postcardiotomy cardiogenic shock, died shortly after receiving mechanical circulatory support. Three of five patients, in whom Levitronix Centrimag was placed electively, were successfully transplanted. The remaining two died of septic complications. In the cohort of patients, in whom ventricular assistance was placed due to DSHF , two required BIVAD placement, and three left ventricular assist devices (LVAD). Conclusion: The Levitronix Centrimag VAD is useful in supporting circulation in patients with acute decompensation of congestive heart failure. It may also be used in patients with postcardiotomy shock. It is an imperative for the device to be placed before irreversible organ dysfunction occurs as the aftermath of malperfusion.Uvod: Liječenje terminalne faze srčanog popuštanja je revolucionarizirano uvođenjem mehaničke potpore srcu. Levitronix Centrimag je uređaj dizajniran u svrhu kratkoročne hemodinamske potpore prije nego što trajnije rješenje cirkulatornog problema postane moguće. Do sad se primijenjivao kao podrška srcu do transplantacije srca, do oporavka srčane funkcije ili do ugradnje trajnijeg oblika mehaničke potpore srcu. Metode: U periodu između rujna 2008 i studenog 2009 Levitronix Centrimag je u našoj ustanovi ugrađen u 6 bolesnika. U jednog bolesnika radilo se o postkardiotomijskom sindromu niskog minutnog volumena. U preostalih pet bolesnika ovaj je oblik mehaničke potpore srcu ugrađen elektivno radi progresivnog kliničkog pogoršanja bolesnika u terminalnoj fazi srčanog popuštanja koje je postalo rezistentno na konzervativnu terapiju. Rezultati: Bolesnik u kojeg je indikacija za mehaničkom potporom srcu bila postavljena hitno u postkardiotomijskom srčanom popuštanju bio je 65 godina star. Imao je ejekcijsku frakciju od 20% dok mu je logistički EuroSCORE bio 25. Prijeoperacijski NT-pro-BNP bio je 9428 pg/ ml dok su serumske vrijednosti laktata prije implantacije Centrimaga bile 8.8 mmol/L. Prosječna dob u skupini bolesnika u kojih je indikacija za mehaničku potporu srcu bila progresivna dekompenzacija srčane funkcije bila je 46 ± 11 godinu. Navedeni bolesnici su imali prosječnu ejekcijsku frakciju od 16 ± 2% dok im je logistički EuroSCORE bio 28 ± 7. Prijeoperacijske vrijednosti serumskog laktata i NT-pro-BNP bile su 1.7±0.8 mmol/L i 9577 ± 3674 pg/ml. U troje bolesnika bila je evidentna kompromitacija funkcije nekog od ostalih organskih sustava. U jednog bolesnika se radilo o akutnom renalnom zatajenju ovisnog o hemodijalizi, u drugog o neurokognitivnoj disfunkciji praćenog sa bubrežnim zatajenjem ali bez potrebe za dijalizom. U trećeg bolesnika radilo se o primarnoj hepatalnoj insuficijenciji. U prva dva bolesnika došlo je do poboljšanja organskih funkcija nakon uspostave mehaničke potpore srcu, dok u trećeg bolesnika nije došlo do promjene hepatalne funkcije budući da ista nije bila uzrokovana malperfuzijom. Bolesnik u kojeg je mehanička potpora srcu stavljena zbog postkardiotomijskog kardiogenog šoka je umro. Troje od pet bolesnika kod kojih je Levitronix Centrimag ugrađen radi dekompenzacije kroničnog zatajenja srca su uspješno transplantirani. Preostalo dvoje bolesnika je umrlo od septičnih komplikacija. U kohorti bolesnika u kojoj je mehanička potpora srcu ugrađena elektivno, dvoje bolesnika je zahtijevalo potporu oba ventrikula dok je u troje ugrađena potpora samo lijevom. Zaključak: Levitronix Centrimag pruža efikasnu hemodinamsku potporu bolesnicima sa kompromitiranom srčanom funkcijom. Neophodno je započeti sa mehaničkom potporom srcu prije nego što se pojave ireverzibilne disfunkcije ostalih organskih sustava

Topical use of antifibrinolytic agents reduces postoperative bleeding: a double-blind, prospective, randomized study

Objective: Postoperative bleeding is still one of the most common complications of cardiac surgery. Antifibrinolytic agents successfully reduce bleeding, but there are controversies concerning adverse effects after their systemic use. By topical application of antifibrinolytic agents in pericardial cavity, most of these effects are avoided. We compared the effects of topically applied aprotinin, tranexamic acid and placebo on postoperative bleeding and transfusion requirements. - - - - - Methods: In this single-center prospective, randomized, double-blind trial, 300 adult cardiac patients were randomized into three groups to receive one million IU of aprotinin (AP group), 2.5g of tranexamic acid (TA group) or placebo (PL group) topically before sternal closure. Groups were comparable with respect to all preoperative and intraoperative variables. Postoperative bleeding, transfusion requirements and hematologic parameters were evaluated. - - - - - Results: Postoperative bleeding within first 12-h period (AP group 433+/-294 [350; 360]ml, TA group 391+/-255 [350; 305]ml, PL group 613+/-505 [525; 348]ml), as well as cumulative blood loss within 24h (AP group 726+/-432 [640; 525]ml, TA group 633+/-343 [545; 335]ml, PL group 903+/-733 [800; 445]ml), showed statistically significant inter-group differences (both p<0.001). Bleeding rates values were significantly higher in placebo group compared to the groups treated with antifibrinolytic agents (AP and TA groups) concerning both variables. Although TA group showed the lowest values, no statistical differences between TA and AP groups were found. Inter-group difference of blood product requirements was not statistically significant. - - - - - Conclusions: Topical use of either tranexamic acid or aprotinin efficiently reduces postoperative bleeding. TA seems to be at least as potent as aprotinin, but potentially safer and with better cost-effectiveness ratio

The Relationship between Prolonged Cerebral Oxygen Desaturation and Postoperative Outcome in Patients Undergoing Coronary Artery Bypass Grafting

58 patients who underwent on-pump coronary artery bypass graft surgery were evaluated for changes in regional cerebral oxygen saturation (rSO2) measured by near infrared spectroscopy (NIRS). If rSO2 during the operation fell to more than 20% under the baseline, standardized interventions were undertaken to maintain rSO2. Despite those interventions, in some cases we observed inability to maintain rSO2 above this threshold. Therefore we divided patients in two subgroups: 1. without prolonged rSO2 desaturation; 2. with prolonged rSO2 desaturation (area under the curve >150 min% for rSO250 min% for rSO2<50% of absolute value). The data were analyzed to determine whether there were major differences in outcome of these two groups. 18 out of 58 patients (31%) had prolonged rSO2 desaturation during operation. There was significantly higher number of diabetic patients in group with prolonged rSO2 desaturation (p=0.02). Intraoperative data revealed significantly more blood consumption during cardiopulmonary bypass (p=0.007) and the need for inotropes (p=0.04) in desaturation group. Three patients in prolonged desaturation group and no one in another group had stroke, coma or stupor (p=0.03). Logistic regression analysis revealed diabetes mellitus and age as predictors for prolonged rSO2 desaturation. We concluded that prolonged intraoperative rSO2 desaturation is significantly associated with worse neurological outcome in patients – nonresponders to standardized interventions for prevention of rSO2 desaturation

Postoperative atrial fibrillation is associated with high on-aspirin platelet reactivity

BACKGROUND: Atrial fibrillation (AF) contributes to a prothrombotic state through platelet activation. It is unclear whether increased platelet aggregability in patients with AF is caused by the underlying cardiovascular condition rather than the arrhythmia per se. We investigated the effect of postoperative atrial fibrillation (POAF) on platelet reactivity after coronary artery bypass grafting (CABG). ----- METHODS: This study is a post hoc analysis from a randomized controlled trial (ClinicalTrials.gov: NCT01159639) based on patients undergoing elective primary CABG. Patients were dichotomized according to POAF. Postoperative platelet function testing with arachidonic acid as the platelet agonist (ASPI test) was used to define high on-aspirin platelet reactivity (HAPR). ΔASPI presented the difference between pre- and postoperative ASPI test values. To account for the isolated effect of POAF on platelet reactivity, a propensity score analysis was applied. ----- RESULTS: Overall incidence of POAF was 23% (92 of 398 patients). HAPR was detected in 54% (214 of 398) of patients. HAPR was more prevalent among patients with POAF when compared with patients without POAF (64.1% versus 50.7%; odds ratio [OR], 1.74; 95% confidence interval [CI], 1.08-2.82; p = 0.023). The propensity score model produced a subcohort of patients that was well balanced for comorbidities. When compared with the matched group without POAF, the POAF group maintained its prevalence for HAPR (64.1% versus 45.7%; OR, 2.13; 95% CI, 1.18-3.85; p = 0.012) and had greater ΔASPI values (15.0 [IQR, 0.0-36.0] vs 8.0 [IQR, -5.5-19.5]; p = 0.030). ----- CONCLUSIONS: The main finding of our study indicates there is added platelet activation in patients with POAF after CABG before and after controlling for pathologic conditions through propensity matching. The present study does not prove a causal association between POAF and HAPR

Neopterin Kinetics after Cardiac Surgery with or without Cardiopulmonary Bypass

Cardiac surgery (CS) with cardiopulmonary bypass (CPB) induces systemic inflammatory response by activating plasma proteins and blood cells. Activated monocytes/macrophages produce inflammatory marker neopterin (NP). The aim was to explore the NP kinetics in first 24 hours after CS according to the CPB use. Significant difference between groups was found for NP levels 12 and 24 hrs after CS, being higher in on-pump group. Strong association was found between NP levels 12 hrs after CS and the length of ICU stay for on-pump group (r=0.744, p<0.001). Strong association was found between preoperative NP levels and the length of ICU stay for those on-pump patients with elevated preoperative NP (r=0.855, p=0.001; linear regression equation y=0.50x – 5.14, p<0.001). Preoperative NP levels higher than 10 nmol/L in on-pump group could predict prolonged ICU stay and outpoint patients at higher risk for developing postoperative complications and, therefore, help to determine the necessary therapeutic interventions

B-mode and Color Doppler Ultrasound of the Forearm Arteries in the Preoperative Screening Prior to Coronary Artery Bypass Grafting

The objective of this paper was to establish the normal findings of B-mode and color Doppler ultrasound of the forearm arteries in candidates for coronary artery bypass grafting with radial artery graft. Examination of radial and ulnar arteries was performed in 127 patients. The vessel diameters and peak systolic velocities were measured and the presence of atherosclerotic changes, calcifications and anatomical variants was assessed. Radial artery proved to be dominant forearm artery with non-significant sideto- side asymmetry. The luminal changes were present in 30% of the patients. Ulnar arteries were more prone to these changes than radial arteries (28.4% vs. 24.4%). The anatomical variants found included ulnar artery hypoplasia in 3.9% of patients and high brachial artery bifurcation in 2.4% of patients. No cases of high-grade stenosis or occlusion were found. The results of the present study indicate that B-mode and color Doppler are valuable methods for preoperative screening as they enable morphological and functional evaluation of the forearm circulation

Off-Pump Coronary Bypass Surgery Adversely affects Alveolar Gas Exchange

While the introduction of off-pump myocardial revascularization (OPCAB) has initially shown promise in reducing respiratory complications inherent to conventional coronary surgery, it has failed to eradicate them. Our study focused on quantifying the lactate release from the lungs and the dysfunction at the level of the alveolar-capillary membrane precipitated by OPCAB at different time points after the insult. Furthermore, we aimed to determine the impact of pulmonary lactate production on systemic lactic acid concentrations. The study was conducted in a prospective observational fashion. Forty consecutive patients undergoing OPCAB were analyzed. The mean patient age was 6010 years. The mean EUROScore was 3.82.9. The alveolar-arterial O2 gradient increased from 19 range 9 to 30 to 26 range 20 to 34 kPa (P<0.001) and remained elevated up to 6 hours after surgery. It rapidly declined again by 18 hours postoperatively. The observed increase in the pulmonary lactate release (PLR) from a baseline value of 0.022 range –0.074 to 0.066 to 0.089 range 0.016 to 0.209 mmol/min/m2 at six hours postoperatively did not reach statistical significance (P=0.105). The systemic arterial lactate (LS) concentration increased from 0.94 range 0.78 to 1.06 to 1.39 range 0.97 to 2.81 mmol/L (P<0.001). The venoarterial pCO2 difference showed no significant change in comparison to baseline values. The mortality in the studied group was 2.5% (1/40). The pulmonary lactate production showed a statistically significant correlation with the systemic lactate concentration (R=0.46; P=0.003). Pulmonary injury following off pump myocardial revascularization was evidenced by a prompt increase in the alveolar-arterial oxygen gradient. The alveolar-arterial O2 gradient correlated with the duration of mechanical ventilation

Cardiac allograft vasculopathy: diagnosis, therapy, and prognosis

Development of cardiac allograft vasculopathy represents the major determinant of long-term survival in patients after heart transplantation. Due to graft denervation, these patients seldom present with classic symptoms of angina pectoris, and the first clinical presentations are progressive heart failure or sudden cardiac death. Although coronary angiography remains the routine technique for coronary artery disease detection, it is not sensitive enough for screening purposes. This is especially the case in the first year after transplantation when diffuse and concentric vascular changes can be easily detected only by intravascular ultrasound. The treatment of the established vasculopathy is disappointing, so the primary effort should be directed toward early prevention and diagnosis. Due to diffuse vascular changes, revascularization procedures are restricted only to a relatively small proportion of patients with favorable coronary anatomy. Percutaneous coronary intervention is preferred over surgical revascularization since it leads to better acute results and patient survival. Although there is no proven long-term advantage of drug-eluting stents for the treatment of in-stent restenosis, they are preferred over bare-metal stents. Severe vasculopathy has a poor prognosis and the only definitive treatment is retransplantation. This article reviews the present knowledge on the pathogenesis, diagnosis, treatment, and prognosis of cardiac allograft vasculopathy